diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2019-01-04 14:07:47 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-01-04 14:07:47 +0300 |
| commit | d538d94f0ca86cfedc892cc427169219acb3c2f7 (patch) | |
| tree | 8363c4ff35907edb5245da737d7f6982bf22b945 /Documentation | |
| parent | f460772291f8171988b2b60141a45706123d0c69 (diff) | |
| parent | 96d4f267e40f9509e8a66e2b39e8b95655617693 (diff) | |
| download | linux-d538d94f0ca86cfedc892cc427169219acb3c2f7.tar.xz | |
Merge branch 'master' into fixes
We have a fix to apply on top of commit 96d4f267e40f ("Remove 'type'
argument from access_ok() function"), so merge master to get it.
Diffstat (limited to 'Documentation')
397 files changed, 14262 insertions, 3008 deletions
diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block index dea212db9df3..7710d4022b19 100644 --- a/Documentation/ABI/testing/sysfs-block +++ b/Documentation/ABI/testing/sysfs-block @@ -244,7 +244,7 @@ Description: What: /sys/block/<disk>/queue/zoned Date: September 2016 -Contact: Damien Le Moal <damien.lemoal@hgst.com> +Contact: Damien Le Moal <damien.lemoal@wdc.com> Description: zoned indicates if the device is a zoned block device and the zone model of the device if it is indeed zoned. @@ -259,6 +259,14 @@ Description: zone commands, they will be treated as regular block devices and zoned will report "none". +What: /sys/block/<disk>/queue/nr_zones +Date: November 2018 +Contact: Damien Le Moal <damien.lemoal@wdc.com> +Description: + nr_zones indicates the total number of zones of a zoned block + device ("host-aware" or "host-managed" zone model). For regular + block devices, the value is always 0. + What: /sys/block/<disk>/queue/chunk_sectors Date: September 2016 Contact: Hannes Reinecke <hare@suse.com> @@ -268,6 +276,6 @@ Description: indicates the size in 512B sectors of the RAID volume stripe segment. For a zoned block device, either host-aware or host-managed, chunk_sectors indicates the - size of 512B sectors of the zones of the device, with + size in 512B sectors of the zones of the device, with the eventual exception of the last zone of the device which may be smaller. diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram index c1513c756af1..9d2339a485c8 100644 --- a/Documentation/ABI/testing/sysfs-block-zram +++ b/Documentation/ABI/testing/sysfs-block-zram @@ -98,3 +98,35 @@ Description: The backing_dev file is read-write and set up backing device for zram to write incompressible pages. For using, user should enable CONFIG_ZRAM_WRITEBACK. + +What: /sys/block/zram<id>/idle +Date: November 2018 +Contact: Minchan Kim <minchan@kernel.org> +Description: + idle file is write-only and mark zram slot as idle. + If system has mounted debugfs, user can see which slots + are idle via /sys/kernel/debug/zram/zram<id>/block_state + +What: /sys/block/zram<id>/writeback +Date: November 2018 +Contact: Minchan Kim <minchan@kernel.org> +Description: + The writeback file is write-only and trigger idle and/or + huge page writeback to backing device. + +What: /sys/block/zram<id>/bd_stat +Date: November 2018 +Contact: Minchan Kim <minchan@kernel.org> +Description: + The bd_stat file is read-only and represents backing device's + statistics (bd_count, bd_reads, bd_writes) in a format + similar to block layer statistics file format. + +What: /sys/block/zram<id>/writeback_limit +Date: November 2018 +Contact: Minchan Kim <minchan@kernel.org> +Description: + The writeback_limit file is read-write and specifies the maximum + amount of writeback ZRAM can do. The limit could be changed + in run time and "0" means disable the limit. + No limit is the initial state. diff --git a/Documentation/ABI/testing/sysfs-bus-thunderbolt b/Documentation/ABI/testing/sysfs-bus-thunderbolt index 151584a1f950..b21fba14689b 100644 --- a/Documentation/ABI/testing/sysfs-bus-thunderbolt +++ b/Documentation/ABI/testing/sysfs-bus-thunderbolt @@ -21,6 +21,15 @@ Description: Holds a comma separated list of device unique_ids that If a device is authorized automatically during boot its boot attribute is set to 1. +What: /sys/bus/thunderbolt/devices/.../domainX/iommu_dma_protection +Date: Mar 2019 +KernelVersion: 4.21 +Contact: thunderbolt-software@lists.01.org +Description: This attribute tells whether the system uses IOMMU + for DMA protection. Value of 1 means IOMMU is used 0 means + it is not (DMA protection is solely based on Thunderbolt + security levels). + What: /sys/bus/thunderbolt/devices/.../domainX/security Date: Sep 2017 KernelVersion: 4.13 diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs index 3ac41774ad3c..a7ce33199457 100644 --- a/Documentation/ABI/testing/sysfs-fs-f2fs +++ b/Documentation/ABI/testing/sysfs-fs-f2fs @@ -92,6 +92,15 @@ Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com> Description: Controls the number of trials to find a victim segment. +What: /sys/fs/f2fs/<disk>/migration_granularity +Date: October 2018 +Contact: "Chao Yu" <yuchao0@huawei.com> +Description: + Controls migration granularity of garbage collection on large + section, it can let GC move partial segment{s} of one section + in one GC cycle, so that dispersing heavy overhead GC to + multiple lightweight one. + What: /sys/fs/f2fs/<disk>/dir_level Date: March 2014 Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com> diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt index ac66ae2509a9..e133ccd60228 100644 --- a/Documentation/DMA-API.txt +++ b/Documentation/DMA-API.txt @@ -60,15 +60,6 @@ the returned memory, like GFP_DMA). :: - void * - dma_zalloc_coherent(struct device *dev, size_t size, - dma_addr_t *dma_handle, gfp_t flag) - -Wraps dma_alloc_coherent() and also zeroes the returned memory if the -allocation attempt succeeded. - -:: - void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_handle) @@ -717,12 +708,15 @@ dma-api/num_errors The number in this file shows how many dma-api/min_free_entries This read-only file can be read to get the minimum number of free dma_debug_entries the allocator has ever seen. If this value goes - down to zero the code will disable itself - because it is not longer reliable. + down to zero the code will attempt to increase + nr_total_entries to compensate. dma-api/num_free_entries The current number of free dma_debug_entries in the allocator. +dma-api/nr_total_entries The total number of dma_debug_entries in the + allocator, both free and used. + dma-api/driver-filter You can write a name of a driver into this file to limit the debug output to requests from that particular driver. Write an empty string to @@ -742,10 +736,15 @@ driver filter at boot time. The debug code will only print errors for that driver afterwards. This filter can be disabled or changed later using debugfs. When the code disables itself at runtime this is most likely because it ran -out of dma_debug_entries. These entries are preallocated at boot. The number -of preallocated entries is defined per architecture. If it is too low for you -boot with 'dma_debug_entries=<your_desired_number>' to overwrite the -architectural default. +out of dma_debug_entries and was unable to allocate more on-demand. 65536 +entries are preallocated at boot - if this is too low for you boot with +'dma_debug_entries=<your_desired_number>' to overwrite the default. Note +that the code allocates entries in batches, so the exact number of +preallocated entries may be greater than the actual number requested. The +code will print to the kernel log each time it has dynamically allocated +as many entries as were initially preallocated. This is to indicate that a +larger preallocation size may be appropriate, or if it happens continually +that a driver may be leaking mappings. :: diff --git a/Documentation/EDID/1024x768.S b/Documentation/EDID/1024x768.S index 6f3e4b75e49e..4aed3f9ab88a 100644 --- a/Documentation/EDID/1024x768.S +++ b/Documentation/EDID/1024x768.S @@ -31,14 +31,13 @@ #define YBLANK 38 #define XOFFSET 8 #define XPULSE 144 -#define YOFFSET (63+3) -#define YPULSE (63+6) +#define YOFFSET 3 +#define YPULSE 6 #define DPI 72 #define VFREQ 60 /* Hz */ #define TIMING_NAME "Linux XGA" #define ESTABLISHED_TIMING2_BITS 0x08 /* Bit 3 -> 1024x768 @60 Hz */ #define HSYNC_POL 0 #define VSYNC_POL 0 -#define CRC 0x55 #include "edid.S" diff --git a/Documentation/EDID/1280x1024.S b/Documentation/EDID/1280x1024.S index bd9bef2a65af..b26dd424cad7 100644 --- a/Documentation/EDID/1280x1024.S +++ b/Documentation/EDID/1280x1024.S @@ -31,14 +31,13 @@ #define YBLANK 42 #define XOFFSET 48 #define XPULSE 112 -#define YOFFSET (63+1) -#define YPULSE (63+3) +#define YOFFSET 1 +#define YPULSE 3 #define DPI 72 #define VFREQ 60 /* Hz */ #define TIMING_NAME "Linux SXGA" /* No ESTABLISHED_TIMINGx_BITS */ #define HSYNC_POL 1 #define VSYNC_POL 1 -#define CRC 0xa0 #include "edid.S" diff --git a/Documentation/EDID/1600x1200.S b/Documentation/EDID/1600x1200.S index a45101c6160c..0d091b282768 100644 --- a/Documentation/EDID/1600x1200.S +++ b/Documentation/EDID/1600x1200.S @@ -31,14 +31,13 @@ #define YBLANK 50 #define XOFFSET 64 #define XPULSE 192 -#define YOFFSET (63+1) -#define YPULSE (63+3) +#define YOFFSET 1 +#define YPULSE 3 #define DPI 72 #define VFREQ 60 /* Hz */ #define TIMING_NAME "Linux UXGA" /* No ESTABLISHED_TIMINGx_BITS */ #define HSYNC_POL 1 #define VSYNC_POL 1 -#define CRC 0x9d #include "edid.S" diff --git a/Documentation/EDID/1680x1050.S b/Documentation/EDID/1680x1050.S index b0d7c69282b4..7dfed9a33eab 100644 --- a/Documentation/EDID/1680x1050.S +++ b/Documentation/EDID/1680x1050.S @@ -31,14 +31,13 @@ #define YBLANK 39 #define XOFFSET 104 #define XPULSE 176 -#define YOFFSET (63+3) -#define YPULSE (63+6) +#define YOFFSET 3 +#define YPULSE 6 #define DPI 96 #define VFREQ 60 /* Hz */ #define TIMING_NAME "Linux WSXGA" /* No ESTABLISHED_TIMINGx_BITS */ #define HSYNC_POL 1 #define VSYNC_POL 1 -#define CRC 0x26 #include "edid.S" diff --git a/Documentation/EDID/1920x1080.S b/Documentation/EDID/1920x1080.S index 3084355e81e7..d6ffbba28e95 100644 --- a/Documentation/EDID/1920x1080.S +++ b/Documentation/EDID/1920x1080.S @@ -31,14 +31,13 @@ #define YBLANK 45 #define XOFFSET 88 #define XPULSE 44 -#define YOFFSET (63+4) -#define YPULSE (63+5) +#define YOFFSET 4 +#define YPULSE 5 #define DPI 96 #define VFREQ 60 /* Hz */ #define TIMING_NAME "Linux FHD" /* No ESTABLISHED_TIMINGx_BITS */ #define HSYNC_POL 1 #define VSYNC_POL 1 -#define CRC 0x05 #include "edid.S" diff --git a/Documentation/EDID/800x600.S b/Documentation/EDID/800x600.S index 6644e26d5801..a5616588de08 100644 --- a/Documentation/EDID/800x600.S +++ b/Documentation/EDID/800x600.S @@ -28,14 +28,13 @@ #define YBLANK 28 #define XOFFSET 40 #define XPULSE 128 -#define YOFFSET (63+1) -#define YPULSE (63+4) +#define YOFFSET 1 +#define YPULSE 4 #define DPI 72 #define VFREQ 60 /* Hz */ #define TIMING_NAME "Linux SVGA" #define ESTABLISHED_TIMING1_BITS 0x01 /* Bit 0: 800x600 @ 60Hz */ #define HSYNC_POL 1 #define VSYNC_POL 1 -#define CRC 0xc2 #include "edid.S" diff --git a/Documentation/EDID/HOWTO.txt b/Documentation/EDID/HOWTO.txt index 835db332289b..539871c3b785 100644 --- a/Documentation/EDID/HOWTO.txt +++ b/Documentation/EDID/HOWTO.txt @@ -45,14 +45,5 @@ EDID: #define YPIX vdisp #define YBLANK vtotal-vdisp -#define YOFFSET (63+(vsyncstart-vdisp)) -#define YPULSE (63+(vsyncend-vsyncstart)) - -The CRC value in the last line - #define CRC 0x55 -also is a bit tricky. After a first version of the binary data set is -created, it must be checked with the "edid-decode" utility which will -most probably complain about a wrong CRC. Fortunately, the utility also -displays the correct CRC which must then be inserted into the source -file. After the make procedure is repeated, the EDID data set is ready -to be used. +#define YOFFSET vsyncstart-vdisp +#define YPULSE vsyncend-vsyncstart diff --git a/Documentation/EDID/Makefile b/Documentation/EDID/Makefile index 17763ca3f12b..85a927dfab02 100644 --- a/Documentation/EDID/Makefile +++ b/Documentation/EDID/Makefile @@ -15,10 +15,21 @@ clean: %.o: %.S @cc -c $^ -%.bin: %.o +%.bin.nocrc: %.o @objcopy -Obinary $^ $@ -%.bin.ihex: %.o +%.crc: %.bin.nocrc + @list=$$(for i in `seq 1 127`; do head -c$$i $^ | tail -c1 \ + | hexdump -v -e '/1 "%02X+"'; done); \ + echo "ibase=16;100-($${list%?})%100" | bc >$@ + +%.p: %.crc %.S + @cc -c -DCRC="$$(cat $*.crc)" -o $@ $*.S + +%.bin: %.p + @objcopy -Obinary $^ $@ + +%.bin.ihex: %.p @objcopy -Oihex $^ $@ @dos2unix $@ 2>/dev/null diff --git a/Documentation/EDID/edid.S b/Documentation/EDID/edid.S index ef082dcc6084..c3d13815526d 100644 --- a/Documentation/EDID/edid.S +++ b/Documentation/EDID/edid.S @@ -47,9 +47,11 @@ #define mfgname2id(v1,v2,v3) \ ((((v1-'@')&0x1f)<<10)+(((v2-'@')&0x1f)<<5)+((v3-'@')&0x1f)) #define swap16(v1) ((v1>>8)+((v1&0xff)<<8)) +#define lsbs2(v1,v2) (((v1&0x0f)<<4)+(v2&0x0f)) #define msbs2(v1,v2) ((((v1>>8)&0x0f)<<4)+((v2>>8)&0x0f)) #define msbs4(v1,v2,v3,v4) \ - (((v1&0x03)>>2)+((v2&0x03)>>4)+((v3&0x03)>>6)+((v4&0x03)>>8)) + ((((v1>>8)&0x03)<<6)+(((v2>>8)&0x03)<<4)+\ + (((v3>>4)&0x03)<<2)+((v4>>4)&0x03)) #define pixdpi2mm(pix,dpi) ((pix*25)/dpi) #define xsize pixdpi2mm(XPIX,DPI) #define ysize pixdpi2mm(YPIX,DPI) @@ -200,9 +202,9 @@ y_msbs: .byte msbs2(YPIX,YBLANK) x_snc_off_lsb: .byte XOFFSET&0xff /* Horizontal sync pulse width pixels 8 lsbits (0-1023) */ x_snc_pls_lsb: .byte XPULSE&0xff -/* Bits 7-4 Vertical sync offset lines 4 lsbits -63) - Bits 3-0 Vertical sync pulse width lines 4 lsbits -63) */ -y_snc_lsb: .byte ((YOFFSET-63)<<4)+(YPULSE-63) +/* Bits 7-4 Vertical sync offset lines 4 lsbits (0-63) + Bits 3-0 Vertical sync pulse width lines 4 lsbits (0-63) */ +y_snc_lsb: .byte lsbs2(YOFFSET, YPULSE) /* Bits 7-6 Horizontal sync offset pixels 2 msbits Bits 5-4 Horizontal sync pulse width pixels 2 msbits Bits 3-2 Vertical sync offset lines 2 msbits diff --git a/Documentation/Makefile b/Documentation/Makefile index 2ca77ad0f238..9786957c6a35 100644 --- a/Documentation/Makefile +++ b/Documentation/Makefile @@ -2,7 +2,7 @@ # Makefile for Sphinx documentation # -subdir-y := +subdir-y := devicetree/bindings/ # You can set these variables from the command line. SPHINXBUILD = sphinx-build diff --git a/Documentation/admin-guide/LSM/SELinux.rst b/Documentation/admin-guide/LSM/SELinux.rst index f722c9b4173a..520a1c2c6fd2 100644 --- a/Documentation/admin-guide/LSM/SELinux.rst +++ b/Documentation/admin-guide/LSM/SELinux.rst @@ -6,7 +6,7 @@ If you want to use SELinux, chances are you will want to use the distro-provided policies, or install the latest reference policy release from - http://oss.tresys.com/projects/refpolicy + https://github.com/SELinuxProject/refpolicy However, if you want to install a dummy policy for testing, you can do using ``mdp`` provided under diff --git a/Documentation/admin-guide/LSM/Smack.rst b/Documentation/admin-guide/LSM/Smack.rst index 6a5826a13aea..6d44f4fdbf59 100644 --- a/Documentation/admin-guide/LSM/Smack.rst +++ b/Documentation/admin-guide/LSM/Smack.rst @@ -818,6 +818,10 @@ Smack supports some mount options: specifies a label to which all labels set on the filesystem must have read access. Not yet enforced. + smackfstransmute=label: + behaves exactly like smackfsroot except that it also + sets the transmute flag on the root of the mount + These mount options apply to all file system types. Smack auditing diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 476722b7b636..7bf3f129c68b 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -56,11 +56,13 @@ v1 is available under Documentation/cgroup-v1/. 5-3-3-2. IO Latency Interface Files 5-4. PID 5-4-1. PID Interface Files - 5-5. Device - 5-6. RDMA - 5-6-1. RDMA Interface Files - 5-7. Misc - 5-7-1. perf_event + 5-5. Cpuset + 5.5-1. Cpuset Interface Files + 5-6. Device + 5-7. RDMA + 5-7-1. RDMA Interface Files + 5-8. Misc + 5-8-1. perf_event 5-N. Non-normative information 5-N-1. CPU controller root cgroup process behaviour 5-N-2. IO controller root cgroup process behaviour @@ -1610,6 +1612,176 @@ through fork() or clone(). These will return -EAGAIN if the creation of a new process would cause a cgroup policy to be violated. +Cpuset +------ + +The "cpuset" controller provides a mechanism for constraining +the CPU and memory node placement of tasks to only the resources +specified in the cpuset interface files in a task's current cgroup. +This is especially valuable on large NUMA systems where placing jobs +on properly sized subsets of the systems with careful processor and +memory placement to reduce cross-node memory access and contention +can improve overall system performance. + +The "cpuset" controller is hierarchical. That means the controller +cannot use CPUs or memory nodes not allowed in its parent. + + +Cpuset Interface Files +~~~~~~~~~~~~~~~~~~~~~~ + + cpuset.cpus + A read-write multiple values file which exists on non-root + cpuset-enabled cgroups. + + It lists the requested CPUs to be used by tasks within this + cgroup. The actual list of CPUs to be granted, however, is + subjected to constraints imposed by its parent and can differ + from the requested CPUs. + + The CPU numbers are comma-separated numbers or ranges. + For example: + + # cat cpuset.cpus + 0-4,6,8-10 + + An empty value indicates that the cgroup is using the same + setting as the nearest cgroup ancestor with a non-empty + "cpuset.cpus" or all the available CPUs if none is found. + + The value of "cpuset.cpus" stays constant until the next update + and won't be affected by any CPU hotplug events. + + cpuset.cpus.effective + A read-only multiple values file which exists on all + cpuset-enabled cgroups. + + It lists the onlined CPUs that are actually granted to this + cgroup by its parent. These CPUs are allowed to be used by + tasks within the current cgroup. + + If "cpuset.cpus" is empty, the "cpuset.cpus.effective" file shows + all the CPUs from the parent cgroup that can be available to + be used by this cgroup. Otherwise, it should be a subset of + "cpuset.cpus" unless none of the CPUs listed in "cpuset.cpus" + can be granted. In this case, it will be treated just like an + empty "cpuset.cpus". + + Its value will be affected by CPU hotplug events. + + cpuset.mems + A read-write multiple values file which exists on non-root + cpuset-enabled cgroups. + + It lists the requested memory nodes to be used by tasks within + this cgroup. The actual list of memory nodes granted, however, + is subjected to constraints imposed by its parent and can differ + from the requested memory nodes. + + The memory node numbers are comma-separated numbers or ranges. + For example: + + # cat cpuset.mems + 0-1,3 + + An empty value indicates that the cgroup is using the same + setting as the nearest cgroup ancestor with a non-empty + "cpuset.mems" or all the available memory nodes if none + is found. + + The value of "cpuset.mems" stays constant until the next update + and won't be affected by any memory nodes hotplug events. + + cpuset.mems.effective + A read-only multiple values file which exists on all + cpuset-enabled cgroups. + + It lists the onlined memory nodes that are actually granted to + this cgroup by its parent. These memory nodes are allowed to + be used by tasks within the current cgroup. + + If "cpuset.mems" is empty, it shows all the memory nodes from the + parent cgroup that will be available to be used by this cgroup. + Otherwise, it should be a subset of "cpuset.mems" unless none of + the memory nodes listed in "cpuset.mems" can be granted. In this + case, it will be treated just like an empty "cpuset.mems". + + Its value will be affected by memory nodes hotplug events. + + cpuset.cpus.partition + A read-write single value file which exists on non-root + cpuset-enabled cgroups. This flag is owned by the parent cgroup + and is not delegatable. + + It accepts only the following input values when written to. + + "root" - a paritition root + "member" - a non-root member of a partition + + When set to be a partition root, the current cgroup is the + root of a new partition or scheduling domain that comprises + itself and all its descendants except those that are separate + partition roots themselves and their descendants. The root + cgroup is always a partition root. + + There are constraints on where a partition root can be set. + It can only be set in a cgroup if all the following conditions + are true. + + 1) The "cpuset.cpus" is not empty and the list of CPUs are + exclusive, i.e. they are not shared by any of its siblings. + 2) The parent cgroup is a partition root. + 3) The "cpuset.cpus" is also a proper subset of the parent's + "cpuset.cpus.effective". + 4) There is no child cgroups with cpuset enabled. This is for + eliminating corner cases that have to be handled if such a + condition is allowed. + + Setting it to partition root will take the CPUs away from the + effective CPUs of the parent cgroup. Once it is set, this + file cannot be reverted back to "member" if there are any child + cgroups with cpuset enabled. + + A parent partition cannot distribute all its CPUs to its + child partitions. There must be at least one cpu left in the + parent partition. + + Once becoming a partition root, changes to "cpuset.cpus" is + generally allowed as long as the first condition above is true, + the change will not take away all the CPUs from the parent + partition and the new "cpuset.cpus" value is a superset of its + children's "cpuset.cpus" values. + + Sometimes, external factors like changes to ancestors' + "cpuset.cpus" or cpu hotplug can cause the state of the partition + root to change. On read, the "cpuset.sched.partition" file + can show the following values. + + "member" Non-root member of a partition + "root" Partition root + "root invalid" Invalid partition root + + It is a partition root if the first 2 partition root conditions + above are true and at least one CPU from "cpuset.cpus" is + granted by the parent cgroup. + + A partition root can become invalid if none of CPUs requested + in "cpuset.cpus" can be granted by the parent cgroup or the + parent cgroup is no longer a partition root itself. In this + case, it is not a real partition even though the restriction + of the first partition root condition above will still apply. + The cpu affinity of all the tasks in the cgroup will then be + associated with CPUs in the nearest ancestor partition. + + An invalid partition root can be transitioned back to a + real partition root if at least one of the requested CPUs + can now be granted by its parent. In this case, the cpu + affinity of all the tasks in the formerly invalid partition + will be associated to the CPUs of the newly formed partition. + Changing the partition state of an invalid partition root to + "member" is always allowed even if child cpusets are present. + + Device controller ----------------- @@ -1879,8 +2051,10 @@ following two functions. wbc_init_bio(@wbc, @bio) Should be called for each bio carrying writeback data and - associates the bio with the inode's owner cgroup. Can be - called anytime between bio allocation and submission. + associates the bio with the inode's owner cgroup and the + corresponding request queue. This must be called after + a queue (device) has been associated with the bio and + before submission. wbc_account_io(@wbc, @page, @bytes) Should be called for each data segment being written out. @@ -1899,7 +2073,7 @@ the configuration, the bio may be executed at a lower priority and if the writeback session is holding shared resources, e.g. a journal entry, may lead to priority inversion. There is no one easy solution for the problem. Filesystems can try to work around specific problem -cases by skipping wbc_init_bio() or using bio_associate_blkcg() +cases by skipping wbc_init_bio() and using bio_associate_blkg() directly. diff --git a/Documentation/admin-guide/devices.rst b/Documentation/admin-guide/devices.rst index 7fadc05330dd..d41671aeaef0 100644 --- a/Documentation/admin-guide/devices.rst +++ b/Documentation/admin-guide/devices.rst @@ -1,3 +1,4 @@ +.. _admin_devices: Linux allocated devices (4.x+ version) ====================================== diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst index fdf72429f801..252e5ef324e5 100644 --- a/Documentation/admin-guide/dynamic-debug-howto.rst +++ b/Documentation/admin-guide/dynamic-debug-howto.rst @@ -110,8 +110,8 @@ If your query set is big, you can batch them too:: ~# cat query-batch-file > <debugfs>/dynamic_debug/control -A another way is to use wildcard. The match rule support ``*`` (matches -zero or more characters) and ``?`` (matches exactly one character).For +Another way is to use wildcards. The match rule supports ``*`` (matches +zero or more characters) and ``?`` (matches exactly one character). For example, you can match all usb drivers:: ~# echo "file drivers/usb/* +p" > <debugfs>/dynamic_debug/control @@ -258,7 +258,7 @@ this boot parameter for debugging purposes. If ``foo`` module is not built-in, ``foo.dyndbg`` will still be processed at boot time, without effect, but will be reprocessed when module is -loaded later. ``dyndbg_query=`` and bare ``dyndbg=`` are only processed at +loaded later. ``ddebug_query=`` and bare ``dyndbg=`` are only processed at boot. @@ -301,7 +301,7 @@ The ``dyndbg`` option is a "fake" module parameter, which means: For ``CONFIG_DYNAMIC_DEBUG`` kernels, any settings given at boot-time (or enabled by ``-DDEBUG`` flag during compilation) can be disabled later via -the sysfs interface if the debug messages are no longer needed:: +the debugfs interface if the debug messages are no longer needed:: echo "module module_name -p" > <debugfs>/dynamic_debug/control diff --git a/Documentation/admin-guide/index.rst b/Documentation/admin-guide/index.rst index 965745d5fb9a..0a491676685e 100644 --- a/Documentation/admin-guide/index.rst +++ b/Documentation/admin-guide/index.rst @@ -76,6 +76,7 @@ configure specific aspects of kernel behavior to your liking. thunderbolt LSM/index mm/index + perf-security .. only:: subproject and html diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index ff4daa780ae8..408781ee142c 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -331,7 +331,7 @@ APC and your system crashes randomly. apic= [APIC,X86] Advanced Programmable Interrupt Controller - Change the output verbosity whilst booting + Change the output verbosity while booting Format: { quiet (default) | verbose | debug } Change the amount of debugging information output when initialising the APIC and IO-APIC components. @@ -486,10 +486,14 @@ cut the overhead, others just disable the usage. So only cgroup_disable=memory is actually worthy} - cgroup_no_v1= [KNL] Disable one, multiple, all cgroup controllers in v1 - Format: { controller[,controller...] | "all" } + cgroup_no_v1= [KNL] Disable cgroup controllers and named hierarchies in v1 + Format: { { controller | "all" | "named" } + [,{ controller | "all" | "named" }...] } Like cgroup_disable, but only applies to cgroup v1; the blacklisted controllers remain available in cgroup2. + "all" blacklists all controllers and "named" disables + named mounts. Specifying both "all" and "named" disables + all v1 hierarchies. cgroup.memory= [KNL] Pass options to the cgroup memory controller. Format: <string> @@ -1686,12 +1690,12 @@ By default, super page will be supported if Intel IOMMU has the capability. With this option, super page will not be supported. - ecs_off [Default Off] - By default, extended context tables will be supported if - the hardware advertises that it has support both for the - extended tables themselves, and also PASID support. With - this option set, extended tables will not be used even - on hardware which claims to support them. + sm_off [Default Off] + By default, scalable mode will be supported if the + hardware advertises that it has support for the scalable + mode translation. With this option set, scalable mode + will not be used even on hardware which claims to support + it. tboot_noforce [Default Off] Do not force the Intel IOMMU enabled under tboot. By default, tboot will force Intel IOMMU on, which diff --git a/Documentation/admin-guide/mm/concepts.rst b/Documentation/admin-guide/mm/concepts.rst index 291699c810d4..c2531b14bf46 100644 --- a/Documentation/admin-guide/mm/concepts.rst +++ b/Documentation/admin-guide/mm/concepts.rst @@ -4,13 +4,13 @@ Concepts overview ================= -The memory management in Linux is complex system that evolved over the -years and included more and more functionality to support variety of +The memory management in Linux is a complex system that evolved over the +years and included more and more functionality to support a variety of systems from MMU-less microcontrollers to supercomputers. The memory -management for systems without MMU is called ``nommu`` and it +management for systems without an MMU is called ``nommu`` and it definitely deserves a dedicated document, which hopefully will be eventually written. Yet, although some of the concepts are the same, -here we assume that MMU is available and CPU can translate a virtual +here we assume that an MMU is available and a CPU can translate a virtual address to a physical address. .. contents:: :local: @@ -21,10 +21,10 @@ Virtual Memory Primer The physical memory in a computer system is a limited resource and even for systems that support memory hotplug there is a hard limit on the amount of memory that can be installed. The physical memory is not -necessary contiguous, it might be accessible as a set of distinct +necessarily contiguous; it might be accessible as a set of distinct address ranges. Besides, different CPU architectures, and even -different implementations of the same architecture have different view -how these address ranges defined. +different implementations of the same architecture have different views +of how these address ranges are defined. All this makes dealing directly with physical memory quite complex and to avoid this complexity a concept of virtual memory was developed. @@ -48,8 +48,8 @@ appropriate kernel configuration option. Each physical memory page can be mapped as one or more virtual pages. These mappings are described by page tables that allow -translation from virtual address used by programs to real address in -the physical memory. The page tables organized hierarchically. +translation from a virtual address used by programs to the physical +memory address. The page tables are organized hierarchically. The tables at the lowest level of the hierarchy contain physical addresses of actual pages used by the software. The tables at higher @@ -121,8 +121,8 @@ Nodes Many multi-processor machines are NUMA - Non-Uniform Memory Access - systems. In such systems the memory is arranged into banks that have different access latency depending on the "distance" from the -processor. Each bank is referred as `node` and for each node Linux -constructs an independent memory management subsystem. A node has it's +processor. Each bank is referred to as a `node` and for each node Linux +constructs an independent memory management subsystem. A node has its own set of zones, lists of free and used pages and various statistics counters. You can find more details about NUMA in :ref:`Documentation/vm/numa.rst <numa>` and in @@ -149,9 +149,9 @@ for program's stack and heap or by explicit calls to mmap(2) system call. Usually, the anonymous mappings only define virtual memory areas that the program is allowed to access. The read accesses will result in creation of a page table entry that references a special physical -page filled with zeroes. When the program performs a write, regular +page filled with zeroes. When the program performs a write, a regular physical page will be allocated to hold the written data. The page -will be marked dirty and if the kernel will decide to repurpose it, +will be marked dirty and if the kernel decides to repurpose it, the dirty page will be swapped out. Reclaim @@ -181,8 +181,8 @@ pressure. The process of freeing the reclaimable physical memory pages and repurposing them is called (surprise!) `reclaim`. Linux can reclaim pages either asynchronously or synchronously, depending on the state -of the system. When system is not loaded, most of the memory is free -and allocation request will be satisfied immediately from the free +of the system. When the system is not loaded, most of the memory is free +and allocation requests will be satisfied immediately from the free pages supply. As the load increases, the amount of the free pages goes down and when it reaches a certain threshold (high watermark), an allocation request will awaken the ``kswapd`` daemon. It will @@ -190,7 +190,7 @@ asynchronously scan memory pages and either just free them if the data they contain is available elsewhere, or evict to the backing storage device (remember those dirty pages?). As memory usage increases even more and reaches another threshold - min watermark - an allocation -will trigger the `direct reclaim`. In this case allocation is stalled +will trigger `direct reclaim`. In this case allocation is stalled until enough memory pages are reclaimed to satisfy the request. Compaction @@ -200,7 +200,7 @@ As the system runs, tasks allocate and free the memory and it becomes fragmented. Although with virtual memory it is possible to present scattered physical pages as virtually contiguous range, sometimes it is necessary to allocate large physically contiguous memory areas. Such -need may arise, for instance, when a device driver requires large +need may arise, for instance, when a device driver requires a large buffer for DMA, or when THP allocates a huge page. Memory `compaction` addresses the fragmentation issue. This mechanism moves occupied pages from the lower part of a memory zone to free pages in the upper part @@ -208,15 +208,16 @@ of the zone. When a compaction scan is finished free pages are grouped together at the beginning of the zone and allocations of large physically contiguous areas become possible. -Like reclaim, the compaction may happen asynchronously in ``kcompactd`` -daemon or synchronously as a result of memory allocation request. +Like reclaim, the compaction may happen asynchronously in the ``kcompactd`` +daemon or synchronously as a result of a memory allocation request. OOM killer ========== -It may happen, that on a loaded machine memory will be exhausted. When -the kernel detects that the system runs out of memory (OOM) it invokes -`OOM killer`. Its mission is simple: all it has to do is to select a -task to sacrifice for the sake of the overall system health. The -selected task is killed in a hope that after it exits enough memory -will be freed to continue normal operation. +It is possible that on a loaded machine memory will be exhausted and the +kernel will be unable to reclaim enough memory to continue to operate. In +order to save the rest of the system, it invokes the `OOM killer`. + +The `OOM killer` selects a task to sacrifice for the sake of the overall +system health. The selected task is killed in a hope that after it exits +enough memory will be freed to continue normal operation. diff --git a/Documentation/admin-guide/perf-security.rst b/Documentation/admin-guide/perf-security.rst new file mode 100644 index 000000000000..f73ebfe9bfe2 --- /dev/null +++ b/Documentation/admin-guide/perf-security.rst @@ -0,0 +1,97 @@ +.. _perf_security: + +Perf Events and tool security +============================= + +Overview +-------- + +Usage of Performance Counters for Linux (perf_events) [1]_ , [2]_ , [3]_ can +impose a considerable risk of leaking sensitive data accessed by monitored +processes. The data leakage is possible both in scenarios of direct usage of +perf_events system call API [2]_ and over data files generated by Perf tool user +mode utility (Perf) [3]_ , [4]_ . The risk depends on the nature of data that +perf_events performance monitoring units (PMU) [2]_ collect and expose for +performance analysis. Having that said perf_events/Perf performance monitoring +is the subject for security access control management [5]_ . + +perf_events/Perf access control +------------------------------- + +To perform security checks, the Linux implementation splits processes into two +categories [6]_ : a) privileged processes (whose effective user ID is 0, referred +to as superuser or root), and b) unprivileged processes (whose effective UID is +nonzero). Privileged processes bypass all kernel security permission checks so +perf_events performance monitoring is fully available to privileged processes +without access, scope and resource restrictions. + +Unprivileged processes are subject to a full security permission check based on +the process's credentials [5]_ (usually: effective UID, effective GID, and +supplementary group list). + +Linux divides the privileges traditionally associated with superuser into +distinct units, known as capabilities [6]_ , which can be independently enabled +and disabled on per-thread basis for processes and files of unprivileged users. + +Unprivileged processes with enabled CAP_SYS_ADMIN capability are treated as +privileged processes with respect to perf_events performance monitoring and +bypass *scope* permissions checks in the kernel. + +Unprivileged processes using perf_events system call API is also subject for +PTRACE_MODE_READ_REALCREDS ptrace access mode check [7]_ , whose outcome +determines whether monitoring is permitted. So unprivileged processes provided +with CAP_SYS_PTRACE capability are effectively permitted to pass the check. + +Other capabilities being granted to unprivileged processes can effectively +enable capturing of additional data required for later performance analysis of +monitored processes or a system. For example, CAP_SYSLOG capability permits +reading kernel space memory addresses from /proc/kallsyms file. + +perf_events/Perf unprivileged users +----------------------------------- + +perf_events/Perf *scope* and *access* control for unprivileged processes is +governed by perf_event_paranoid [2]_ setting: + +-1: + Impose no *scope* and *access* restrictions on using perf_events performance + monitoring. Per-user per-cpu perf_event_mlock_kb [2]_ locking limit is + ignored when allocating memory buffers for storing performance data. + This is the least secure mode since allowed monitored *scope* is + maximized and no perf_events specific limits are imposed on *resources* + allocated for performance monitoring. + +>=0: + *scope* includes per-process and system wide performance monitoring + but excludes raw tracepoints and ftrace function tracepoints monitoring. + CPU and system events happened when executing either in user or + in kernel space can be monitored and captured for later analysis. + Per-user per-cpu perf_event_mlock_kb locking limit is imposed but + ignored for unprivileged processes with CAP_IPC_LOCK [6]_ capability. + +>=1: + *scope* includes per-process performance monitoring only and excludes + system wide performance monitoring. CPU and system events happened when + executing either in user or in kernel space can be monitored and + captured for later analysis. Per-user per-cpu perf_event_mlock_kb + locking limit is imposed but ignored for unprivileged processes with + CAP_IPC_LOCK capability. + +>=2: + *scope* includes per-process performance monitoring only. CPU and system + events happened when executing in user space only can be monitored and + captured for later analysis. Per-user per-cpu perf_event_mlock_kb + locking limit is imposed but ignored for unprivileged processes with + CAP_IPC_LOCK capability. + +Bibliography +------------ + +.. [1] `<https://lwn.net/Articles/337493/>`_ +.. [2] `<http://man7.org/linux/man-pages/man2/perf_event_open.2.html>`_ +.. [3] `<http://web.eece.maine.edu/~vweaver/projects/perf_events/>`_ +.. [4] `<https://perf.wiki.kernel.org/index.php/Main_Page>`_ +.. [5] `<https://www.kernel.org/doc/html/latest/security/credentials.html>`_ +.. [6] `<http://man7.org/linux/man-pages/man7/capabilities.7.html>`_ +.. [7] `<http://man7.org/linux/man-pages/man2/ptrace.2.html>`_ + diff --git a/Documentation/admin-guide/ras.rst b/Documentation/admin-guide/ras.rst index 197896718f81..c7495e42e6f4 100644 --- a/Documentation/admin-guide/ras.rst +++ b/Documentation/admin-guide/ras.rst @@ -54,7 +54,7 @@ those errors are correctable. Types of errors --------------- -Most mechanisms used on modern systems use use technologies like Hamming +Most mechanisms used on modern systems use technologies like Hamming Codes that allow error correction when the number of errors on a bit packet is below a threshold. If the number of errors is above, those mechanisms can indicate with a high degree of confidence that an error happened, but diff --git a/Documentation/admin-guide/security-bugs.rst b/Documentation/admin-guide/security-bugs.rst index 30187d49dc2c..dcd6c93c7aac 100644 --- a/Documentation/admin-guide/security-bugs.rst +++ b/Documentation/admin-guide/security-bugs.rst @@ -44,7 +44,7 @@ only valid reason for deferring the publication of a fix is to accommodate the logistics of QA and large scale rollouts which require release coordination. -Whilst embargoed information may be shared with trusted individuals in +While embargoed information may be shared with trusted individuals in order to develop a fix, such information will not be published alongside the fix or on any other disclosure channel without the permission of the reporter. This includes but is not limited to the original bug report diff --git a/Documentation/admin-guide/thunderbolt.rst b/Documentation/admin-guide/thunderbolt.rst index 35fccba6a9a6..898ad78f3cc7 100644 --- a/Documentation/admin-guide/thunderbolt.rst +++ b/Documentation/admin-guide/thunderbolt.rst @@ -133,6 +133,26 @@ If the user still wants to connect the device they can either approve the device without a key or write a new key and write 1 to the ``authorized`` file to get the new key stored on the device NVM. +DMA protection utilizing IOMMU +------------------------------ +Recent systems from 2018 and forward with Thunderbolt ports may natively +support IOMMU. This means that Thunderbolt security is handled by an IOMMU +so connected devices cannot access memory regions outside of what is +allocated for them by drivers. When Linux is running on such system it +automatically enables IOMMU if not enabled by the user already. These +systems can be identified by reading ``1`` from +``/sys/bus/thunderbolt/devices/domainX/iommu_dma_protection`` attribute. + +The driver does not do anything special in this case but because DMA +protection is handled by the IOMMU, security levels (if set) are +redundant. For this reason some systems ship with security level set to +``none``. Other systems have security level set to ``user`` in order to +support downgrade to older OS, so users who want to automatically +authorize devices when IOMMU DMA protection is enabled can use the +following ``udev`` rule:: + + ACTION=="add", SUBSYSTEM=="thunderbolt", ATTRS{iommu_dma_protection}=="1", ATTR{authorized}=="0", ATTR{authorized}="1" + Upgrading NVM on Thunderbolt device or host ------------------------------------------- Since most of the functionality is handled in firmware running on a diff --git a/Documentation/arm/Booting b/Documentation/arm/Booting index 259f00af3ab3..f1f965ce93d6 100644 --- a/Documentation/arm/Booting +++ b/Documentation/arm/Booting @@ -126,7 +126,7 @@ tagged list. The boot loader must pass at a minimum the size and location of the system memory, and the root filesystem location. The dtb must be placed in a region of memory where the kernel decompressor will not -overwrite it, whilst remaining within the region which will be covered +overwrite it, while remaining within the region which will be covered by the kernel's low-memory mapping. A safe location is just above the 128MiB boundary from start of RAM. diff --git a/Documentation/arm/Samsung-S3C24XX/GPIO.txt b/Documentation/arm/Samsung-S3C24XX/GPIO.txt index 0ebd7e2244d0..e8f918b96123 100644 --- a/Documentation/arm/Samsung-S3C24XX/GPIO.txt +++ b/Documentation/arm/Samsung-S3C24XX/GPIO.txt @@ -55,7 +55,7 @@ out s3c2410 API, then here are some notes on the process. as they have the same arguments, and can either take the pin specific values, or the more generic special-function-number arguments. -3) s3c2410_gpio_pullup() changes have the problem that whilst the +3) s3c2410_gpio_pullup() changes have the problem that while the s3c2410_gpio_pullup(x, 1) can be easily translated to the s3c_gpio_setpull(x, S3C_GPIO_PULL_NONE), the s3c2410_gpio_pullup(x, 0) are not so easy. diff --git a/Documentation/arm/Samsung-S3C24XX/Overview.txt b/Documentation/arm/Samsung-S3C24XX/Overview.txt index 359587b2367b..00d3c3141e21 100644 --- a/Documentation/arm/Samsung-S3C24XX/Overview.txt +++ b/Documentation/arm/Samsung-S3C24XX/Overview.txt @@ -17,7 +17,7 @@ Introduction versions. The S3C2416 and S3C2450 devices are very similar and S3C2450 support is - included under the arch/arm/mach-s3c2416 directory. Note, whilst core + included under the arch/arm/mach-s3c2416 directory. Note, while core support for these SoCs is in, work on some of the extra peripherals and extra interrupts is still ongoing. diff --git a/Documentation/arm/Samsung-S3C24XX/Suspend.txt b/Documentation/arm/Samsung-S3C24XX/Suspend.txt index 1ca63b3e5635..cb4f0c0cdf9d 100644 --- a/Documentation/arm/Samsung-S3C24XX/Suspend.txt +++ b/Documentation/arm/Samsung-S3C24XX/Suspend.txt @@ -87,7 +87,7 @@ Debugging suspending, which means that use of printascii() or similar direct access to the UARTs will cause the debug to stop. - 2) Whilst the pm code itself will attempt to re-enable the UART clocks, + 2) While the pm code itself will attempt to re-enable the UART clocks, care should be taken that any external clock sources that the UARTs rely on are still enabled at that point. diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt index 207eca58efaa..ac18b488cb5e 100644 --- a/Documentation/block/biodoc.txt +++ b/Documentation/block/biodoc.txt @@ -65,7 +65,6 @@ Description of Contents: 3.2.3 I/O completion 3.2.4 Implications for drivers that do not interpret bios (don't handle multiple segments) - 3.2.5 Request command tagging 3.3 I/O submission 4. The I/O scheduler 5. Scalability related changes @@ -708,93 +707,6 @@ is crossed on completion of a transfer. (The end*request* functions should be used if only if the request has come down from block/bio path, not for direct access requests which only specify rq->buffer without a valid rq->bio) -3.2.5 Generic request command tagging - -3.2.5.1 Tag helpers - -Block now offers some simple generic functionality to help support command -queueing (typically known as tagged command queueing), ie manage more than -one outstanding command on a queue at any given time. - - blk_queue_init_tags(struct request_queue *q, int depth) - - Initialize internal command tagging structures for a maximum - depth of 'depth'. - - blk_queue_free_tags((struct request_queue *q) - - Teardown tag info associated with the queue. This will be done - automatically by block if blk_queue_cleanup() is called on a queue - that is using tagging. - -The above are initialization and exit management, the main helpers during -normal operations are: - - blk_queue_start_tag(struct request_queue *q, struct request *rq) - - Start tagged operation for this request. A free tag number between - 0 and 'depth' is assigned to the request (rq->tag holds this number), - and 'rq' is added to the internal tag management. If the maximum depth - for this queue is already achieved (or if the tag wasn't started for - some other reason), 1 is returned. Otherwise 0 is returned. - - blk_queue_end_tag(struct request_queue *q, struct request *rq) - - End tagged operation on this request. 'rq' is removed from the internal - book keeping structures. - -To minimize struct request and queue overhead, the tag helpers utilize some -of the same request members that are used for normal request queue management. -This means that a request cannot both be an active tag and be on the queue -list at the same time. blk_queue_start_tag() will remove the request, but -the driver must remember to call blk_queue_end_tag() before signalling -completion of the request to the block layer. This means ending tag -operations before calling end_that_request_last()! For an example of a user -of these helpers, see the IDE tagged command queueing support. - -3.2.5.2 Tag info - -Some block functions exist to query current tag status or to go from a -tag number to the associated request. These are, in no particular order: - - blk_queue_tagged(q) - - Returns 1 if the queue 'q' is using tagging, 0 if not. - - blk_queue_tag_request(q, tag) - - Returns a pointer to the request associated with tag 'tag'. - - blk_queue_tag_depth(q) - - Return current queue depth. - - blk_queue_tag_queue(q) - - Returns 1 if the queue can accept a new queued command, 0 if we are - at the maximum depth already. - - blk_queue_rq_tagged(rq) - - Returns 1 if the request 'rq' is tagged. - -3.2.5.2 Internal structure - -Internally, block manages tags in the blk_queue_tag structure: - - struct blk_queue_tag { - struct request **tag_index; /* array or pointers to rq */ - unsigned long *tag_map; /* bitmap of free tags */ - struct list_head busy_list; /* fifo list of busy tags */ - int busy; /* queue depth */ - int max_depth; /* max queue depth */ - }; - -Most of the above is simple and straight forward, however busy_list may need -a bit of explaining. Normally we don't care too much about request ordering, -but in the event of any barrier requests in the tag queue we need to ensure -that requests are restarted in the order they were queue. - 3.3 I/O Submission The routine submit_bio() is used to submit a single io. Higher level i/o diff --git a/Documentation/block/cfq-iosched.txt b/Documentation/block/cfq-iosched.txt deleted file mode 100644 index 895bd3813115..000000000000 --- a/Documentation/block/cfq-iosched.txt +++ /dev/null @@ -1,291 +0,0 @@ -CFQ (Complete Fairness Queueing) -=============================== - -The main aim of CFQ scheduler is to provide a fair allocation of the disk -I/O bandwidth for all the processes which requests an I/O operation. - -CFQ maintains the per process queue for the processes which request I/O -operation(synchronous requests). In case of asynchronous requests, all the -requests from all the processes are batched together according to their -process's I/O priority. - -CFQ ioscheduler tunables -======================== - -slice_idle ----------- -This specifies how long CFQ should idle for next request on certain cfq queues -(for sequential workloads) and service trees (for random workloads) before -queue is expired and CFQ selects next queue to dispatch from. - -By default slice_idle is a non-zero value. That means by default we idle on -queues/service trees. This can be very helpful on highly seeky media like -single spindle SATA/SAS disks where we can cut down on overall number of -seeks and see improved throughput. - -Setting slice_idle to 0 will remove all the idling on queues/service tree -level and one should see an overall improved throughput on faster storage -devices like multiple SATA/SAS disks in hardware RAID configuration. The down -side is that isolation provided from WRITES also goes down and notion of -IO priority becomes weaker. - -So depending on storage and workload, it might be useful to set slice_idle=0. -In general I think for SATA/SAS disks and software RAID of SATA/SAS disks -keeping slice_idle enabled should be useful. For any configurations where -there are multiple spindles behind single LUN (Host based hardware RAID -controller or for storage arrays), setting slice_idle=0 might end up in better -throughput and acceptable latencies. - -back_seek_max -------------- -This specifies, given in Kbytes, the maximum "distance" for backward seeking. -The distance is the amount of space from the current head location to the -sectors that are backward in terms of distance. - -This parameter allows the scheduler to anticipate requests in the "backward" -direction and consider them as being the "next" if they are within this -distance from the current head location. - -back_seek_penalty ------------------ -This parameter is used to compute the cost of backward seeking. If the -backward distance of request is just 1/back_seek_penalty from a "front" -request, then the seeking cost of two requests is considered equivalent. - -So scheduler will not bias toward one or the other request (otherwise scheduler -will bias toward front request). Default value of back_seek_penalty is 2. - -fifo_expire_async ------------------ -This parameter is used to set the timeout of asynchronous requests. Default -value of this is 248ms. - -fifo_expire_sync ----------------- -This parameter is used to set the timeout of synchronous requests. Default -value of this is 124ms. In case to favor synchronous requests over asynchronous -one, this value should be decreased relative to fifo_expire_async. - -group_idle ------------ -This parameter forces idling at the CFQ group level instead of CFQ -queue level. This was introduced after a bottleneck was observed -in higher end storage due to idle on sequential queue and allow dispatch -from a single queue. The idea with this parameter is that it can be run with -slice_idle=0 and group_idle=8, so that idling does not happen on individual -queues in the group but happens overall on the group and thus still keeps the -IO controller working. -Not idling on individual queues in the group will dispatch requests from -multiple queues in the group at the same time and achieve higher throughput -on higher end storage. - -Default value for this parameter is 8ms. - -low_latency ------------ -This parameter is used to enable/disable the low latency mode of the CFQ -scheduler. If enabled, CFQ tries to recompute the slice time for each process -based on the target_latency set for the system. This favors fairness over -throughput. Disabling low latency (setting it to 0) ignores target latency, -allowing each process in the system to get a full time slice. - -By default low latency mode is enabled. - -target_latency --------------- -This parameter is used to calculate the time slice for a process if cfq's -latency mode is enabled. It will ensure that sync requests have an estimated -latency. But if sequential workload is higher(e.g. sequential read), -then to meet the latency constraints, throughput may decrease because of less -time for each process to issue I/O request before the cfq queue is switched. - -Though this can be overcome by disabling the latency_mode, it may increase -the read latency for some applications. This parameter allows for changing -target_latency through the sysfs interface which can provide the balanced -throughput and read latency. - -Default value for target_latency is 300ms. - -slice_async ------------ -This parameter is same as of slice_sync but for asynchronous queue. The -default value is 40ms. - -slice_async_rq --------------- -This parameter is used to limit the dispatching of asynchronous request to -device request queue in queue's slice time. The maximum number of request that -are allowed to be dispatched also depends upon the io priority. Default value -for this is 2. - -slice_sync ----------- -When a queue is selected for execution, the queues IO requests are only -executed for a certain amount of time(time_slice) before switching to another -queue. This parameter is used to calculate the time slice of synchronous -queue. - -time_slice is computed using the below equation:- -time_slice = slice_sync + (slice_sync/5 * (4 - prio)). To increase the -time_slice of synchronous queue, increase the value of slice_sync. Default -value is 100ms. - -quantum -------- -This specifies the number of request dispatched to the device queue. In a -queue's time slice, a request will not be dispatched if the number of request -in the device exceeds this parameter. This parameter is used for synchronous -request. - -In case of storage with several disk, this setting can limit the parallel -processing of request. Therefore, increasing the value can improve the -performance although this can cause the latency of some I/O to increase due -to more number of requests. - -CFQ Group scheduling -==================== - -CFQ supports blkio cgroup and has "blkio." prefixed files in each -blkio cgroup directory. It is weight-based and there are four knobs -for configuration - weight[_device] and leaf_weight[_device]. -Internal cgroup nodes (the ones with children) can also have tasks in -them, so the former two configure how much proportion the cgroup as a -whole is entitled to at its parent's level while the latter two -configure how much proportion the tasks in the cgroup have compared to -its direct children. - -Another way to think about it is assuming that each internal node has -an implicit leaf child node which hosts all the tasks whose weight is -configured by leaf_weight[_device]. Let's assume a blkio hierarchy -composed of five cgroups - root, A, B, AA and AB - with the following -weights where the names represent the hierarchy. - - weight leaf_weight - root : 125 125 - A : 500 750 - B : 250 500 - AA : 500 500 - AB : 1000 500 - -root never has a parent making its weight is meaningless. For backward -compatibility, weight is always kept in sync with leaf_weight. B, AA -and AB have no child and thus its tasks have no children cgroup to -compete with. They always get 100% of what the cgroup won at the -parent level. Considering only the weights which matter, the hierarchy -looks like the following. - - root - / | \ - A B leaf - 500 250 125 - / | \ - AA AB leaf - 500 1000 750 - -If all cgroups have active IOs and competing with each other, disk -time will be distributed like the following. - -Distribution below root. The total active weight at this level is -A:500 + B:250 + C:125 = 875. - - root-leaf : 125 / 875 =~ 14% - A : 500 / 875 =~ 57% - B(-leaf) : 250 / 875 =~ 28% - -A has children and further distributes its 57% among the children and -the implicit leaf node. The total active weight at this level is -AA:500 + AB:1000 + A-leaf:750 = 2250. - - A-leaf : ( 750 / 2250) * A =~ 19% - AA(-leaf) : ( 500 / 2250) * A =~ 12% - AB(-leaf) : (1000 / 2250) * A =~ 25% - -CFQ IOPS Mode for group scheduling -=================================== -Basic CFQ design is to provide priority based time slices. Higher priority -process gets bigger time slice and lower priority process gets smaller time -slice. Measuring time becomes harder if storage is fast and supports NCQ and -it would be better to dispatch multiple requests from multiple cfq queues in -request queue at a time. In such scenario, it is not possible to measure time -consumed by single queue accurately. - -What is possible though is to measure number of requests dispatched from a -single queue and also allow dispatch from multiple cfq queue at the same time. -This effectively becomes the fairness in terms of IOPS (IO operations per -second). - -If one sets slice_idle=0 and if storage supports NCQ, CFQ internally switches -to IOPS mode and starts providing fairness in terms of number of requests -dispatched. Note that this mode switching takes effect only for group -scheduling. For non-cgroup users nothing should change. - -CFQ IO scheduler Idling Theory -=============================== -Idling on a queue is primarily about waiting for the next request to come -on same queue after completion of a request. In this process CFQ will not -dispatch requests from other cfq queues even if requests are pending there. - -The rationale behind idling is that it can cut down on number of seeks -on rotational media. For example, if a process is doing dependent -sequential reads (next read will come on only after completion of previous -one), then not dispatching request from other queue should help as we -did not move the disk head and kept on dispatching sequential IO from -one queue. - -CFQ has following service trees and various queues are put on these trees. - - sync-idle sync-noidle async - -All cfq queues doing synchronous sequential IO go on to sync-idle tree. -On this tree we idle on each queue individually. - -All synchronous non-sequential queues go on sync-noidle tree. Also any -synchronous write request which is not marked with REQ_IDLE goes on this -service tree. On this tree we do not idle on individual queues instead idle -on the whole group of queues or the tree. So if there are 4 queues waiting -for IO to dispatch we will idle only once last queue has dispatched the IO -and there is no more IO on this service tree. - -All async writes go on async service tree. There is no idling on async -queues. - -CFQ has some optimizations for SSDs and if it detects a non-rotational -media which can support higher queue depth (multiple requests at in -flight at a time), then it cuts down on idling of individual queues and -all the queues move to sync-noidle tree and only tree idle remains. This -tree idling provides isolation with buffered write queues on async tree. - -FAQ -=== -Q1. Why to idle at all on queues not marked with REQ_IDLE. - -A1. We only do tree idle (all queues on sync-noidle tree) on queues not marked - with REQ_IDLE. This helps in providing isolation with all the sync-idle - queues. Otherwise in presence of many sequential readers, other - synchronous IO might not get fair share of disk. - - For example, if there are 10 sequential readers doing IO and they get - 100ms each. If a !REQ_IDLE request comes in, it will be scheduled - roughly after 1 second. If after completion of !REQ_IDLE request we - do not idle, and after a couple of milli seconds a another !REQ_IDLE - request comes in, again it will be scheduled after 1second. Repeat it - and notice how a workload can lose its disk share and suffer due to - multiple sequential readers. - - fsync can generate dependent IO where bunch of data is written in the - context of fsync, and later some journaling data is written. Journaling - data comes in only after fsync has finished its IO (atleast for ext4 - that seemed to be the case). Now if one decides not to idle on fsync - thread due to !REQ_IDLE, then next journaling write will not get - scheduled for another second. A process doing small fsync, will suffer - badly in presence of multiple sequential readers. - - Hence doing tree idling on threads using !REQ_IDLE flag on requests - provides isolation from multiple sequential readers and at the same - time we do not idle on individual threads. - -Q2. When to specify REQ_IDLE -A2. I would think whenever one is doing synchronous write and expecting - more writes to be dispatched from same context soon, should be able - to specify REQ_IDLE on writes and that probably should work well for - most of the cases. diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt index 2c1e67058fd3..39e286d7afc9 100644 --- a/Documentation/block/queue-sysfs.txt +++ b/Documentation/block/queue-sysfs.txt @@ -64,7 +64,7 @@ guess, the kernel will put the process issuing IO to sleep for an amount of time, before entering a classic poll loop. This mode might be a little slower than pure classic polling, but it will be more efficient. If set to a value larger than 0, the kernel will put the process issuing -IO to sleep for this amont of microseconds before entering classic +IO to sleep for this amount of microseconds before entering classic polling. iostats (RW) @@ -194,4 +194,31 @@ blk-throttle makes decision based on the samplings. Lower time means cgroups have more smooth throughput, but higher CPU overhead. This exists only when CONFIG_BLK_DEV_THROTTLING_LOW is enabled. +zoned (RO) +---------- +This indicates if the device is a zoned block device and the zone model of the +device if it is indeed zoned. The possible values indicated by zoned are +"none" for regular block devices and "host-aware" or "host-managed" for zoned +block devices. The characteristics of host-aware and host-managed zoned block +devices are described in the ZBC (Zoned Block Commands) and ZAC +(Zoned Device ATA Command Set) standards. These standards also define the +"drive-managed" zone model. However, since drive-managed zoned block devices +do not support zone commands, they will be treated as regular block devices +and zoned will report "none". + +nr_zones (RO) +------------- +For zoned block devices (zoned attribute indicating "host-managed" or +"host-aware"), this indicates the total number of zones of the device. +This is always 0 for regular block devices. + +chunk_sectors (RO) +------------------ +This has different meaning depending on the type of the block device. +For a RAID device (dm-raid), chunk_sectors indicates the size in 512B sectors +of the RAID volume stripe segment. For a zoned block device, either host-aware +or host-managed, chunk_sectors indicates the size in 512B sectors of the zones +of the device, with the eventual exception of the last zone of the device which +may be smaller. + Jens Axboe <jens.axboe@oracle.com>, February 2009 diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index 3c1b5ab54bc0..436c5e98e1b6 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -164,11 +164,14 @@ reset WO trigger device reset mem_used_max WO reset the `mem_used_max' counter (see later) mem_limit WO specifies the maximum amount of memory ZRAM can use to store the compressed data +writeback_limit WO specifies the maximum amount of write IO zram can + write out to backing device as 4KB unit max_comp_streams RW the number of possible concurrent compress operations comp_algorithm RW show and change the compression algorithm compact WO trigger memory compaction debug_stat RO this file is used for zram debugging purposes backing_dev RW set up backend storage for zram to write out +idle WO mark allocated slot as idle User space is advised to use the following files to read the device statistics. @@ -220,6 +223,17 @@ line of text and contains the following stats separated by whitespace: pages_compacted the number of pages freed during compaction huge_pages the number of incompressible pages +File /sys/block/zram<id>/bd_stat + +The stat file represents device's backing device statistics. It consists of +a single line of text and contains the following stats separated by whitespace: + bd_count size of data written in backing device. + Unit: 4K bytes + bd_reads the number of reads from backing device + Unit: 4K bytes + bd_writes the number of writes to backing device + Unit: 4K bytes + 9) Deactivate: swapoff /dev/zram0 umount /dev/zram1 @@ -237,11 +251,60 @@ line of text and contains the following stats separated by whitespace: = writeback -With incompressible pages, there is no memory saving with zram. -Instead, with CONFIG_ZRAM_WRITEBACK, zram can write incompressible page +With CONFIG_ZRAM_WRITEBACK, zram can write idle/incompressible page to backing storage rather than keeping it in memory. -User should set up backing device via /sys/block/zramX/backing_dev -before disksize setting. +To use the feature, admin should set up backing device via + + "echo /dev/sda5 > /sys/block/zramX/backing_dev" + +before disksize setting. It supports only partition at this moment. +If admin want to use incompressible page writeback, they could do via + + "echo huge > /sys/block/zramX/write" + +To use idle page writeback, first, user need to declare zram pages +as idle. + + "echo all > /sys/block/zramX/idle" + +From now on, any pages on zram are idle pages. The idle mark +will be removed until someone request access of the block. +IOW, unless there is access request, those pages are still idle pages. + +Admin can request writeback of those idle pages at right timing via + + "echo idle > /sys/block/zramX/writeback" + +With the command, zram writeback idle pages from memory to the storage. + +If there are lots of write IO with flash device, potentially, it has +flash wearout problem so that admin needs to design write limitation +to guarantee storage health for entire product life. +To overcome the concern, zram supports "writeback_limit". +The "writeback_limit"'s default value is 0 so that it doesn't limit +any writeback. If admin want to measure writeback count in a certain +period, he could know it via /sys/block/zram0/bd_stat's 3rd column. + +If admin want to limit writeback as per-day 400M, he could do it +like below. + + MB_SHIFT=20 + 4K_SHIFT=12 + echo $((400<<MB_SHIFT>>4K_SHIFT)) > \ + /sys/block/zram0/writeback_limit. + +If admin want to allow further write again, he could do it like below + + echo 0 > /sys/block/zram0/writeback_limit + +If admin want to see remaining writeback budget since he set, + + cat /sys/block/zram0/writeback_limit + +The writeback_limit count will reset whenever you reset zram(e.g., +system reboot, echo 1 > /sys/block/zramX/reset) so keeping how many of +writeback happened until you reset the zram to allocate extra writeback +budget in next setting is user's job. = memory tracking @@ -251,16 +314,17 @@ pages of the process with*pagemap. If you enable the feature, you could see block state via /sys/kernel/debug/zram/zram0/block_state". The output is as follows, - 300 75.033841 .wh - 301 63.806904 s.. - 302 63.806919 ..h + 300 75.033841 .wh. + 301 63.806904 s... + 302 63.806919 ..hi First column is zram's block index. Second column is access time since the system was booted Third column is state of the block. (s: same page w: written page to backing store -h: huge page) +h: huge page +i: idle page) First line of above example says 300th block is accessed at 75.033841sec and the block's state is huge so it is written back to the backing diff --git a/Documentation/core-api/assoc_array.rst b/Documentation/core-api/assoc_array.rst index 8231b915c939..792bbf9939e1 100644 --- a/Documentation/core-api/assoc_array.rst +++ b/Documentation/core-api/assoc_array.rst @@ -34,7 +34,7 @@ properties: 8. The array can iterated over. The objects will not necessarily come out in key order. -9. The array can be iterated over whilst it is being modified, provided the +9. The array can be iterated over while it is being modified, provided the RCU readlock is being held by the iterator. Note, however, under these circumstances, some objects may be seen more than once. If this is a problem, the iterator should lock against modification. Objects will not @@ -42,7 +42,7 @@ properties: 10. Objects in the array can be looked up by means of their index key. -11. Objects can be looked up whilst the array is being modified, provided the +11. Objects can be looked up while the array is being modified, provided the RCU readlock is being held by the thread doing the look up. The implementation uses a tree of 16-pointer nodes internally that are indexed @@ -273,7 +273,7 @@ The function will return ``0`` if successful and ``-ENOMEM`` if there wasn't enough memory. It is possible for other threads to iterate over or search the array under -the RCU read lock whilst this function is in progress. The caller should +the RCU read lock while this function is in progress. The caller should lock exclusively against other modifiers of the array. diff --git a/Documentation/core-api/memory-allocation.rst b/Documentation/core-api/memory-allocation.rst index f8bb9aa120c4..8954a88ff5b7 100644 --- a/Documentation/core-api/memory-allocation.rst +++ b/Documentation/core-api/memory-allocation.rst @@ -1,3 +1,5 @@ +.. _memory-allocation: + ======================= Memory Allocation Guide ======================= diff --git a/Documentation/core-api/mm-api.rst b/Documentation/core-api/mm-api.rst index 5ce1ec1dd066..aa8e54b85221 100644 --- a/Documentation/core-api/mm-api.rst +++ b/Documentation/core-api/mm-api.rst @@ -46,11 +46,20 @@ The Slab Cache .. kernel-doc:: mm/slab.c :export: +.. kernel-doc:: mm/slab_common.c + :export: + .. kernel-doc:: mm/util.c :functions: kfree_const kvmalloc_node kvfree -More Memory Management Functions -================================ +Virtually Contiguous Mappings +============================= + +.. kernel-doc:: mm/vmalloc.c + :export: + +File Mapping and Page Cache +=========================== .. kernel-doc:: mm/readahead.c :export: @@ -58,23 +67,28 @@ More Memory Management Functions .. kernel-doc:: mm/filemap.c :export: -.. kernel-doc:: mm/memory.c +.. kernel-doc:: mm/page-writeback.c :export: -.. kernel-doc:: mm/vmalloc.c +.. kernel-doc:: mm/truncate.c :export: -.. kernel-doc:: mm/page_alloc.c - :internal: +Memory pools +============ .. kernel-doc:: mm/mempool.c :export: +DMA pools +========= + .. kernel-doc:: mm/dmapool.c :export: -.. kernel-doc:: mm/page-writeback.c - :export: +More Memory Management Functions +================================ -.. kernel-doc:: mm/truncate.c +.. kernel-doc:: mm/memory.c :export: + +.. kernel-doc:: mm/page_alloc.c diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index ff48b55040ef..a7fae4538946 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -412,6 +412,24 @@ Examples:: Passed by reference. +Time and date (struct rtc_time) +------------------------------- + +:: + + %ptR YYYY-mm-ddTHH:MM:SS + %ptRd YYYY-mm-dd + %ptRt HH:MM:SS + %ptR[dt][r] + +For printing date and time as represented by struct rtc_time structure in +human readable format. + +By default year will be incremented by 1900 and month by 1. Use %ptRr (raw) +to suppress this behaviour. + +Passed by reference. + struct clk ---------- diff --git a/Documentation/crypto/api.rst b/Documentation/crypto/api.rst index 2e519193ab4a..b91b31736df8 100644 --- a/Documentation/crypto/api.rst +++ b/Documentation/crypto/api.rst @@ -1,15 +1,6 @@ Programming Interface ===================== -Please note that the kernel crypto API contains the AEAD givcrypt API -(crypto_aead_giv\* and aead_givcrypt\* function calls in -include/crypto/aead.h). This API is obsolete and will be removed in the -future. To obtain the functionality of an AEAD cipher with internal IV -generation, use the IV generator as a regular cipher. For example, -rfc4106(gcm(aes)) is the AEAD cipher with external IV generation and -seqniv(rfc4106(gcm(aes))) implies that the kernel crypto API generates -the IV. Different IV generators are available. - .. class:: toc-title Table of contents diff --git a/Documentation/crypto/architecture.rst b/Documentation/crypto/architecture.rst index ca2d09b991f5..ee8ff0762d7f 100644 --- a/Documentation/crypto/architecture.rst +++ b/Documentation/crypto/architecture.rst @@ -157,10 +157,6 @@ applicable to a cipher, it is not displayed: - rng for random number generator - - givcipher for cipher with associated IV generator (see the geniv - entry below for the specification of the IV generator type used by - the cipher implementation) - - kpp for a Key-agreement Protocol Primitive (KPP) cipher such as an ECDH or DH implementation @@ -174,16 +170,7 @@ applicable to a cipher, it is not displayed: - digestsize: output size of the message digest -- geniv: IV generation type: - - - eseqiv for encrypted sequence number based IV generation - - - seqiv for sequence number based IV generation - - - chainiv for chain iv generation - - - <builtin> is a marker that the cipher implements IV generation and - handling as it is specific to the given cipher +- geniv: IV generator (obsolete) Key Sizes --------- @@ -218,10 +205,6 @@ the aforementioned cipher types: - CRYPTO_ALG_TYPE_ABLKCIPHER Asynchronous multi-block cipher -- CRYPTO_ALG_TYPE_GIVCIPHER Asynchronous multi-block cipher packed - together with an IV generator (see geniv field in the /proc/crypto - listing for the known IV generators) - - CRYPTO_ALG_TYPE_KPP Key-agreement Protocol Primitive (KPP) such as an ECDH or DH implementation @@ -338,18 +321,14 @@ uses the API applicable to the cipher type specified for the block. The following call sequence is applicable when the IPSEC layer triggers an encryption operation with the esp_output function. During -configuration, the administrator set up the use of rfc4106(gcm(aes)) as -the cipher for ESP. The following call sequence is now depicted in the -ASCII art above: +configuration, the administrator set up the use of seqiv(rfc4106(gcm(aes))) +as the cipher for ESP. The following call sequence is now depicted in +the ASCII art above: 1. esp_output() invokes crypto_aead_encrypt() to trigger an encryption operation of the AEAD cipher with IV generator. - In case of GCM, the SEQIV implementation is registered as GIVCIPHER - in crypto_rfc4106_alloc(). - - The SEQIV performs its operation to generate an IV where the core - function is seqiv_geniv(). + The SEQIV generates the IV. 2. Now, SEQIV uses the AEAD API function calls to invoke the associated AEAD cipher. In our case, during the instantiation of SEQIV, the diff --git a/Documentation/dev-tools/coccinelle.rst b/Documentation/dev-tools/coccinelle.rst index aa14f05cabb1..00a3409b0c28 100644 --- a/Documentation/dev-tools/coccinelle.rst +++ b/Documentation/dev-tools/coccinelle.rst @@ -4,6 +4,8 @@ .. highlight:: none +.. _devtools_coccinelle: + Coccinelle ========== diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst index e313925fb0fa..b0522a4dd107 100644 --- a/Documentation/dev-tools/index.rst +++ b/Documentation/dev-tools/index.rst @@ -3,8 +3,8 @@ Development tools for the kernel ================================ This document is a collection of documents about development tools that can -be used to work on the kernel. For now, the documents have been pulled -together without any significant effot to integrate them into a coherent +be used to work on the kernel. For now, the documents have been pulled +together without any significant effort to integrate them into a coherent whole; patches welcome! .. class:: toc-title diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index aabc8738b3d8..b72d07d70239 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -4,15 +4,25 @@ The Kernel Address Sanitizer (KASAN) Overview -------- -KernelAddressSANitizer (KASAN) is a dynamic memory error detector. It provides -a fast and comprehensive solution for finding use-after-free and out-of-bounds -bugs. +KernelAddressSANitizer (KASAN) is a dynamic memory error detector designed to +find out-of-bound and use-after-free bugs. KASAN has two modes: generic KASAN +(similar to userspace ASan) and software tag-based KASAN (similar to userspace +HWASan). -KASAN uses compile-time instrumentation for checking every memory access, -therefore you will need a GCC version 4.9.2 or later. GCC 5.0 or later is -required for detection of out-of-bounds accesses to stack or global variables. +KASAN uses compile-time instrumentation to insert validity checks before every +memory access, and therefore requires a compiler version that supports that. -Currently KASAN is supported only for the x86_64 and arm64 architectures. +Generic KASAN is supported in both GCC and Clang. With GCC it requires version +4.9.2 or later for basic support and version 5.0 or later for detection of +out-of-bounds accesses for stack and global variables and for inline +instrumentation mode (see the Usage section). With Clang it requires version +7.0.0 or later and it doesn't support detection of out-of-bounds accesses for +global variables yet. + +Tag-based KASAN is only supported in Clang and requires version 7.0.0 or later. + +Currently generic KASAN is supported for the x86_64, arm64, xtensa and s390 +architectures, and tag-based KASAN is supported only for arm64. Usage ----- @@ -21,12 +31,14 @@ To enable KASAN configure kernel with:: CONFIG_KASAN = y -and choose between CONFIG_KASAN_OUTLINE and CONFIG_KASAN_INLINE. Outline and -inline are compiler instrumentation types. The former produces smaller binary -the latter is 1.1 - 2 times faster. Inline instrumentation requires a GCC -version 5.0 or later. +and choose between CONFIG_KASAN_GENERIC (to enable generic KASAN) and +CONFIG_KASAN_SW_TAGS (to enable software tag-based KASAN). + +You also need to choose between CONFIG_KASAN_OUTLINE and CONFIG_KASAN_INLINE. +Outline and inline are compiler instrumentation types. The former produces +smaller binary while the latter is 1.1 - 2 times faster. -KASAN works with both SLUB and SLAB memory allocators. +Both KASAN modes work with both SLUB and SLAB memory allocators. For better bug detection and nicer reporting, enable CONFIG_STACKTRACE. To disable instrumentation for specific files or directories, add a line @@ -43,85 +55,85 @@ similar to the following to the respective kernel Makefile: Error reports ~~~~~~~~~~~~~ -A typical out of bounds access report looks like this:: +A typical out-of-bounds access generic KASAN report looks like this:: ================================================================== - BUG: AddressSanitizer: out of bounds access in kmalloc_oob_right+0x65/0x75 [test_kasan] at addr ffff8800693bc5d3 - Write of size 1 by task modprobe/1689 - ============================================================================= - BUG kmalloc-128 (Not tainted): kasan error - ----------------------------------------------------------------------------- - - Disabling lock debugging due to kernel taint - INFO: Allocated in kmalloc_oob_right+0x3d/0x75 [test_kasan] age=0 cpu=0 pid=1689 - __slab_alloc+0x4b4/0x4f0 - kmem_cache_alloc_trace+0x10b/0x190 - kmalloc_oob_right+0x3d/0x75 [test_kasan] - init_module+0x9/0x47 [test_kasan] - do_one_initcall+0x99/0x200 - load_module+0x2cb3/0x3b20 - SyS_finit_module+0x76/0x80 - system_call_fastpath+0x12/0x17 - INFO: Slab 0xffffea0001a4ef00 objects=17 used=7 fp=0xffff8800693bd728 flags=0x100000000004080 - INFO: Object 0xffff8800693bc558 @offset=1368 fp=0xffff8800693bc720 - - Bytes b4 ffff8800693bc548: 00 00 00 00 00 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ........ZZZZZZZZ - Object ffff8800693bc558: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk - Object ffff8800693bc568: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk - Object ffff8800693bc578: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk - Object ffff8800693bc588: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk - Object ffff8800693bc598: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk - Object ffff8800693bc5a8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk - Object ffff8800693bc5b8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk - Object ffff8800693bc5c8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk. - Redzone ffff8800693bc5d8: cc cc cc cc cc cc cc cc ........ - Padding ffff8800693bc718: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ - CPU: 0 PID: 1689 Comm: modprobe Tainted: G B 3.18.0-rc1-mm1+ #98 - Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 - ffff8800693bc000 0000000000000000 ffff8800693bc558 ffff88006923bb78 - ffffffff81cc68ae 00000000000000f3 ffff88006d407600 ffff88006923bba8 - ffffffff811fd848 ffff88006d407600 ffffea0001a4ef00 ffff8800693bc558 + BUG: KASAN: slab-out-of-bounds in kmalloc_oob_right+0xa8/0xbc [test_kasan] + Write of size 1 at addr ffff8801f44ec37b by task insmod/2760 + + CPU: 1 PID: 2760 Comm: insmod Not tainted 4.19.0-rc3+ #698 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 Call Trace: - [<ffffffff81cc68ae>] dump_stack+0x46/0x58 - [<ffffffff811fd848>] print_trailer+0xf8/0x160 - [<ffffffffa00026a7>] ? kmem_cache_oob+0xc3/0xc3 [test_kasan] - [<ffffffff811ff0f5>] object_err+0x35/0x40 - [<ffffffffa0002065>] ? kmalloc_oob_right+0x65/0x75 [test_kasan] - [<ffffffff8120b9fa>] kasan_report_error+0x38a/0x3f0 - [<ffffffff8120a79f>] ? kasan_poison_shadow+0x2f/0x40 - [<ffffffff8120b344>] ? kasan_unpoison_shadow+0x14/0x40 - [<ffffffff8120a79f>] ? kasan_poison_shadow+0x2f/0x40 - [<ffffffffa00026a7>] ? kmem_cache_oob+0xc3/0xc3 [test_kasan] - [<ffffffff8120a995>] __asan_store1+0x75/0xb0 - [<ffffffffa0002601>] ? kmem_cache_oob+0x1d/0xc3 [test_kasan] - [<ffffffffa0002065>] ? kmalloc_oob_right+0x65/0x75 [test_kasan] - [<ffffffffa0002065>] kmalloc_oob_right+0x65/0x75 [test_kasan] - [<ffffffffa00026b0>] init_module+0x9/0x47 [test_kasan] - [<ffffffff810002d9>] do_one_initcall+0x99/0x200 - [<ffffffff811e4e5c>] ? __vunmap+0xec/0x160 - [<ffffffff81114f63>] load_module+0x2cb3/0x3b20 - [<ffffffff8110fd70>] ? m_show+0x240/0x240 - [<ffffffff81115f06>] SyS_finit_module+0x76/0x80 - [<ffffffff81cd3129>] system_call_fastpath+0x12/0x17 + dump_stack+0x94/0xd8 + print_address_description+0x73/0x280 + kasan_report+0x144/0x187 + __asan_report_store1_noabort+0x17/0x20 + kmalloc_oob_right+0xa8/0xbc [test_kasan] + kmalloc_tests_init+0x16/0x700 [test_kasan] + do_one_initcall+0xa5/0x3ae + do_init_module+0x1b6/0x547 + load_module+0x75df/0x8070 + __do_sys_init_module+0x1c6/0x200 + __x64_sys_init_module+0x6e/0xb0 + do_syscall_64+0x9f/0x2c0 + entry_SYSCALL_64_after_hwframe+0x44/0xa9 + RIP: 0033:0x7f96443109da + RSP: 002b:00007ffcf0b51b08 EFLAGS: 00000202 ORIG_RAX: 00000000000000af + RAX: ffffffffffffffda RBX: 000055dc3ee521a0 RCX: 00007f96443109da + RDX: 00007f96445cff88 RSI: 0000000000057a50 RDI: 00007f9644992000 + RBP: 000055dc3ee510b0 R08: 0000000000000003 R09: 0000000000000000 + R10: 00007f964430cd0a R11: 0000000000000202 R12: 00007f96445cff88 + R13: 000055dc3ee51090 R14: 0000000000000000 R15: 0000000000000000 + + Allocated by task 2760: + save_stack+0x43/0xd0 + kasan_kmalloc+0xa7/0xd0 + kmem_cache_alloc_trace+0xe1/0x1b0 + kmalloc_oob_right+0x56/0xbc [test_kasan] + kmalloc_tests_init+0x16/0x700 [test_kasan] + do_one_initcall+0xa5/0x3ae + do_init_module+0x1b6/0x547 + load_module+0x75df/0x8070 + __do_sys_init_module+0x1c6/0x200 + __x64_sys_init_module+0x6e/0xb0 + do_syscall_64+0x9f/0x2c0 + entry_SYSCALL_64_after_hwframe+0x44/0xa9 + + Freed by task 815: + save_stack+0x43/0xd0 + __kasan_slab_free+0x135/0x190 + kasan_slab_free+0xe/0x10 + kfree+0x93/0x1a0 + umh_complete+0x6a/0xa0 + call_usermodehelper_exec_async+0x4c3/0x640 + ret_from_fork+0x35/0x40 + + The buggy address belongs to the object at ffff8801f44ec300 + which belongs to the cache kmalloc-128 of size 128 + The buggy address is located 123 bytes inside of + 128-byte region [ffff8801f44ec300, ffff8801f44ec380) + The buggy address belongs to the page: + page:ffffea0007d13b00 count:1 mapcount:0 mapping:ffff8801f7001640 index:0x0 + flags: 0x200000000000100(slab) + raw: 0200000000000100 ffffea0007d11dc0 0000001a0000001a ffff8801f7001640 + raw: 0000000000000000 0000000080150015 00000001ffffffff 0000000000000000 + page dumped because: kasan: bad access detected + Memory state around the buggy address: - ffff8800693bc300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc - ffff8800693bc380: fc fc 00 00 00 00 00 00 00 00 00 00 00 00 00 fc - ffff8800693bc400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc - ffff8800693bc480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc - ffff8800693bc500: fc fc fc fc fc fc fc fc fc fc fc 00 00 00 00 00 - >ffff8800693bc580: 00 00 00 00 00 00 00 00 00 00 03 fc fc fc fc fc - ^ - ffff8800693bc600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc - ffff8800693bc680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc - ffff8800693bc700: fc fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb - ffff8800693bc780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb - ffff8800693bc800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb + ffff8801f44ec200: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb + ffff8801f44ec280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc + >ffff8801f44ec300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 03 + ^ + ffff8801f44ec380: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb + ffff8801f44ec400: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ================================================================== -The header of the report discribe what kind of bug happened and what kind of -access caused it. It's followed by the description of the accessed slub object -(see 'SLUB Debug output' section in Documentation/vm/slub.rst for details) and -the description of the accessed memory page. +The header of the report provides a short summary of what kind of bug happened +and what kind of access caused it. It's followed by a stack trace of the bad +access, a stack trace of where the accessed memory was allocated (in case bad +access happens on a slab object), and a stack trace of where the object was +freed (in case of a use-after-free bug report). Next comes a description of +the accessed slab object and information about the accessed memory page. In the last section the report shows memory state around the accessed address. Reading this part requires some understanding of how KASAN works. @@ -138,18 +150,24 @@ inaccessible memory like redzones or freed memory (see mm/kasan/kasan.h). In the report above the arrows point to the shadow byte 03, which means that the accessed address is partially accessible. +For tag-based KASAN this last report section shows the memory tags around the +accessed address (see Implementation details section). + Implementation details ---------------------- +Generic KASAN +~~~~~~~~~~~~~ + From a high level, our approach to memory error detection is similar to that of kmemcheck: use shadow memory to record whether each byte of memory is safe -to access, and use compile-time instrumentation to check shadow memory on each -memory access. +to access, and use compile-time instrumentation to insert checks of shadow +memory on each memory access. -AddressSanitizer dedicates 1/8 of kernel memory to its shadow memory -(e.g. 16TB to cover 128TB on x86_64) and uses direct mapping with a scale and -offset to translate a memory address to its corresponding shadow address. +Generic KASAN dedicates 1/8th of kernel memory to its shadow memory (e.g. 16TB +to cover 128TB on x86_64) and uses direct mapping with a scale and offset to +translate a memory address to its corresponding shadow address. Here is the function which translates an address to its corresponding shadow address:: @@ -162,12 +180,38 @@ address:: where ``KASAN_SHADOW_SCALE_SHIFT = 3``. -Compile-time instrumentation used for checking memory accesses. Compiler inserts -function calls (__asan_load*(addr), __asan_store*(addr)) before each memory -access of size 1, 2, 4, 8 or 16. These functions check whether memory access is -valid or not by checking corresponding shadow memory. +Compile-time instrumentation is used to insert memory access checks. Compiler +inserts function calls (__asan_load*(addr), __asan_store*(addr)) before each +memory access of size 1, 2, 4, 8 or 16. These functions check whether memory +access is valid or not by checking corresponding shadow memory. GCC 5.0 has possibility to perform inline instrumentation. Instead of making function calls GCC directly inserts the code to check the shadow memory. This option significantly enlarges kernel but it gives x1.1-x2 performance boost over outline instrumented kernel. + +Software tag-based KASAN +~~~~~~~~~~~~~~~~~~~~~~~~ + +Tag-based KASAN uses the Top Byte Ignore (TBI) feature of modern arm64 CPUs to +store a pointer tag in the top byte of kernel pointers. Like generic KASAN it +uses shadow memory to store memory tags associated with each 16-byte memory +cell (therefore it dedicates 1/16th of the kernel memory for shadow memory). + +On each memory allocation tag-based KASAN generates a random tag, tags the +allocated memory with this tag, and embeds this tag into the returned pointer. +Software tag-based KASAN uses compile-time instrumentation to insert checks +before each memory access. These checks make sure that tag of the memory that +is being accessed is equal to tag of the pointer that is used to access this +memory. In case of a tag mismatch tag-based KASAN prints a bug report. + +Software tag-based KASAN also has two instrumentation modes (outline, that +emits callbacks to check memory accesses; and inline, that performs the shadow +memory checks inline). With outline instrumentation mode, a bug report is +simply printed from the function that performs the access check. With inline +instrumentation a brk instruction is emitted by the compiler, and a dedicated +brk handler is used to print bug reports. + +A potential expansion of this mode is a hardware tag-based mode, which would +use hardware memory tagging support instead of compiler instrumentation and +manual shadow memory manipulation. diff --git a/Documentation/dev-tools/kselftest.rst b/Documentation/dev-tools/kselftest.rst index dad1bb8711e2..7756f7a7c23b 100644 --- a/Documentation/dev-tools/kselftest.rst +++ b/Documentation/dev-tools/kselftest.rst @@ -9,7 +9,7 @@ and booting a kernel. On some systems, hot-plug tests could hang forever waiting for cpu and memory to be ready to be offlined. A special hot-plug target is created -to run full range of hot-plug tests. In default mode, hot-plug tests run +to run the full range of hot-plug tests. In default mode, hot-plug tests run in safe mode with a limited scope. In limited mode, cpu-hotplug test is run on a single cpu as opposed to all hotplug capable cpus, and memory hotplug test is run on 2% of hotplug capable memory instead of 10%. @@ -89,9 +89,9 @@ Note that some tests will require root privileges. Install selftests ================= -You can use kselftest_install.sh tool installs selftests in default -location which is tools/testing/selftests/kselftest or a user specified -location. +You can use the kselftest_install.sh tool to install selftests in the +default location, which is tools/testing/selftests/kselftest, or in a +user specified location. To install selftests in default location:: @@ -109,7 +109,7 @@ Running installed selftests Kselftest install as well as the Kselftest tarball provide a script named "run_kselftest.sh" to run the tests. -You can simply do the following to run the installed Kselftests. Please +You can simply do the following to run the installed Kselftests. Please note some tests will require root privileges:: $ cd kselftest @@ -139,7 +139,7 @@ Contributing new tests (details) default. TEST_CUSTOM_PROGS should be used by tests that require custom build - rule and prevent common build rule use. + rules and prevent common build rule use. TEST_PROGS are for test shell scripts. Please ensure shell script has its exec bit set. Otherwise, lib.mk run_tests will generate a warning. diff --git a/Documentation/device-mapper/dm-raid.txt b/Documentation/device-mapper/dm-raid.txt index 52a719b49afd..2355bef14653 100644 --- a/Documentation/device-mapper/dm-raid.txt +++ b/Documentation/device-mapper/dm-raid.txt @@ -146,7 +146,7 @@ The target is named "raid" and it accepts the following parameters: [data_offset <sectors>] This option value defines the offset into each data device where the data starts. This is used to provide out-of-place - reshaping space to avoid writing over data whilst + reshaping space to avoid writing over data while changing the layout of stripes, hence an interruption/crash may happen at any time without the risk of losing data. E.g. when adding devices to an existing raid set during diff --git a/Documentation/devicetree/bindings/.gitignore b/Documentation/devicetree/bindings/.gitignore new file mode 100644 index 000000000000..ef82fcfcccab --- /dev/null +++ b/Documentation/devicetree/bindings/.gitignore @@ -0,0 +1,2 @@ +*.example.dts +processed-schema.yaml diff --git a/Documentation/devicetree/bindings/Makefile b/Documentation/devicetree/bindings/Makefile new file mode 100644 index 000000000000..6e5cef0ed6fb --- /dev/null +++ b/Documentation/devicetree/bindings/Makefile @@ -0,0 +1,27 @@ +# SPDX-License-Identifier: GPL-2.0 +DT_DOC_CHECKER ?= dt-doc-validate +DT_EXTRACT_EX ?= dt-extract-example +DT_MK_SCHEMA ?= dt-mk-schema +DT_MK_SCHEMA_FLAGS := $(if $(DT_SCHEMA_FILES), -u) + +quiet_cmd_chk_binding = CHKDT $(patsubst $(srctree)/%,%,$<) + cmd_chk_binding = $(DT_DOC_CHECKER) $< ; \ + $(DT_EXTRACT_EX) $< > $@ + +$(obj)/%.example.dts: $(src)/%.yaml FORCE + $(call if_changed,chk_binding) + +DT_TMP_SCHEMA := processed-schema.yaml +extra-y += $(DT_TMP_SCHEMA) + +quiet_cmd_mk_schema = SCHEMA $@ + cmd_mk_schema = $(DT_MK_SCHEMA) $(DT_MK_SCHEMA_FLAGS) -o $@ $(filter-out FORCE, $^) + +DT_DOCS = $(shell cd $(srctree)/$(src) && find * -name '*.yaml') +DT_SCHEMA_FILES ?= $(addprefix $(src)/,$(DT_DOCS)) + +extra-y += $(patsubst $(src)/%.yaml,%.example.dts, $(DT_SCHEMA_FILES)) +extra-y += $(patsubst $(src)/%.yaml,%.example.dtb, $(DT_SCHEMA_FILES)) + +$(obj)/$(DT_TMP_SCHEMA): $(DT_SCHEMA_FILES) FORCE + $(call if_changed,mk_schema) diff --git a/Documentation/devicetree/bindings/arm/altera.txt b/Documentation/devicetree/bindings/arm/altera.txt deleted file mode 100644 index 558735aacca8..000000000000 --- a/Documentation/devicetree/bindings/arm/altera.txt +++ /dev/null @@ -1,14 +0,0 @@ -Altera's SoCFPGA platform device tree bindings ---------------------------------------------- - -Boards with Cyclone 5 SoC: -Required root node properties: -compatible = "altr,socfpga-cyclone5", "altr,socfpga"; - -Boards with Arria 5 SoC: -Required root node properties: -compatible = "altr,socfpga-arria5", "altr,socfpga"; - -Boards with Arria 10 SoC: -Required root node properties: -compatible = "altr,socfpga-arria10", "altr,socfpga"; diff --git a/Documentation/devicetree/bindings/arm/altera.yaml b/Documentation/devicetree/bindings/arm/altera.yaml new file mode 100644 index 000000000000..49e0362ddc11 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/altera.yaml @@ -0,0 +1,20 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/altera.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Altera's SoCFPGA platform device tree bindings + +maintainers: + - Dinh Nguyen <dinguyen@kernel.org> + +properties: + compatible: + items: + - enum: + - altr,socfpga-cyclone5 + - altr,socfpga-arria5 + - altr,socfpga-arria10 + - const: altr,socfpga +... diff --git a/Documentation/devicetree/bindings/arm/altera/socfpga-clk-manager.txt b/Documentation/devicetree/bindings/arm/altera/socfpga-clk-manager.txt deleted file mode 100644 index 2c28f1d12f45..000000000000 --- a/Documentation/devicetree/bindings/arm/altera/socfpga-clk-manager.txt +++ /dev/null @@ -1,11 +0,0 @@ -Altera SOCFPGA Clock Manager - -Required properties: -- compatible : "altr,clk-mgr" -- reg : Should contain base address and length for Clock Manager - -Example: - clkmgr@ffd04000 { - compatible = "altr,clk-mgr"; - reg = <0xffd04000 0x1000>; - }; diff --git a/Documentation/devicetree/bindings/arm/altera/socfpga-clk-manager.yaml b/Documentation/devicetree/bindings/arm/altera/socfpga-clk-manager.yaml new file mode 100644 index 000000000000..e4131fa42b26 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/altera/socfpga-clk-manager.yaml @@ -0,0 +1,31 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/altera/socfpga-clk-manager.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Altera SOCFPGA Clock Manager + +maintainers: + - Dinh Nguyen <dinguyen@kernel.org> + +description: test + +properties: + compatible: + items: + - const: altr,clk-mgr + reg: + maxItems: 1 + +required: + - compatible + +examples: + - | + clkmgr@ffd04000 { + compatible = "altr,clk-mgr"; + reg = <0xffd04000 0x1000>; + }; + +... diff --git a/Documentation/devicetree/bindings/arm/amlogic,scpi.txt b/Documentation/devicetree/bindings/arm/amlogic,scpi.txt index 7b9a861e9306..5ab59da052df 100644 --- a/Documentation/devicetree/bindings/arm/amlogic,scpi.txt +++ b/Documentation/devicetree/bindings/arm/amlogic,scpi.txt @@ -17,4 +17,11 @@ Required sub-node properties: - compatible : should be "amlogic,meson-gxbb-scp-shmem" for SRAM based shared memory on Amlogic GXBB SoC. +Sensor bindings for the sensors based on SCPI Message Protocol +-------------------------------------------------------------- +SCPI provides an API to access the various sensors on the SoC. + +Required properties: +- compatible : should be "amlogic,meson-gxbb-scpi-sensors". + [0] Documentation/devicetree/bindings/arm/arm,scpi.txt diff --git a/Documentation/devicetree/bindings/arm/amlogic.txt b/Documentation/devicetree/bindings/arm/amlogic.txt index 4498292b833d..8dbc259081e4 100644 --- a/Documentation/devicetree/bindings/arm/amlogic.txt +++ b/Documentation/devicetree/bindings/arm/amlogic.txt @@ -91,8 +91,10 @@ Board compatible values (alphabetically, grouped by SoC): - "amlogic,p230" (Meson gxl s905d) - "amlogic,p231" (Meson gxl s905d) + - "phicomm,n1" (Meson gxl s905d) - "amlogic,p241" (Meson gxl s805x) + - "libretech,aml-s805x-ac" (Meson gxl s805x) - "amlogic,p281" (Meson gxl s905w) - "oranth,tx3-mini" (Meson gxl s905w) diff --git a/Documentation/devicetree/bindings/arm/atmel-sysregs.txt b/Documentation/devicetree/bindings/arm/atmel-sysregs.txt index 4b96608ad692..14f319f694b7 100644 --- a/Documentation/devicetree/bindings/arm/atmel-sysregs.txt +++ b/Documentation/devicetree/bindings/arm/atmel-sysregs.txt @@ -158,14 +158,24 @@ Security Module (SECUMOD) The Security Module macrocell provides all necessary secure functions to avoid voltage, temperature, frequency and mechanical attacks on the chip. It also -embeds secure memories that can be scrambled +embeds secure memories that can be scrambled. + +The Security Module also offers the PIOBU pins which can be used as GPIO pins. +Note that they maintain their voltage during Backup/Self-refresh. required properties: - compatible: Should be "atmel,<chip>-secumod", "syscon". <chip> can be "sama5d2". - reg: Should contain registers location and length +- gpio-controller: Marks the port as GPIO controller. +- #gpio-cells: There are 2. The pin number is the + first, the second represents additional + parameters such as GPIO_ACTIVE_HIGH/LOW. + secumod@fc040000 { compatible = "atmel,sama5d2-secumod", "syscon"; reg = <0xfc040000 0x100>; + gpio-controller; + #gpio-cells = <2>; }; diff --git a/Documentation/devicetree/bindings/arm/calxeda.txt b/Documentation/devicetree/bindings/arm/calxeda.txt deleted file mode 100644 index 25fcf96795ca..000000000000 --- a/Documentation/devicetree/bindings/arm/calxeda.txt +++ /dev/null @@ -1,15 +0,0 @@ -Calxeda Platforms Device Tree Bindings ------------------------------------------------ - -Boards with Calxeda Cortex-A9 based ECX-1000 (Highbank) SOC shall have the -following properties. - -Required root node properties: - - compatible = "calxeda,highbank"; - - -Boards with Calxeda Cortex-A15 based ECX-2000 SOC shall have the following -properties. - -Required root node properties: - - compatible = "calxeda,ecx-2000"; diff --git a/Documentation/devicetree/bindings/arm/calxeda.yaml b/Documentation/devicetree/bindings/arm/calxeda.yaml new file mode 100644 index 000000000000..aa5571d23c39 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/calxeda.yaml @@ -0,0 +1,22 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/calxeda.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Calxeda Platforms Device Tree Bindings + +maintainers: + - Rob Herring <robh@kernel.org> +description: |+ + Bindings for boards with Calxeda Cortex-A9 based ECX-1000 (Highbank) SOC + or Cortex-A15 based ECX-2000 SOCs + +properties: + $nodename: + const: '/' + compatible: + items: + - enum: + - calxeda,highbank + - calxeda,ecx-2000 diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt deleted file mode 100644 index b0198a1cf403..000000000000 --- a/Documentation/devicetree/bindings/arm/cpus.txt +++ /dev/null @@ -1,490 +0,0 @@ -================= -ARM CPUs bindings -================= - -The device tree allows to describe the layout of CPUs in a system through -the "cpus" node, which in turn contains a number of subnodes (ie "cpu") -defining properties for every cpu. - -Bindings for CPU nodes follow the Devicetree Specification, available from: - -https://www.devicetree.org/specifications/ - -with updates for 32-bit and 64-bit ARM systems provided in this document. - -================================ -Convention used in this document -================================ - -This document follows the conventions described in the Devicetree -Specification, with the addition: - -- square brackets define bitfields, eg reg[7:0] value of the bitfield in - the reg property contained in bits 7 down to 0 - -===================================== -cpus and cpu node bindings definition -===================================== - -The ARM architecture, in accordance with the Devicetree Specification, -requires the cpus and cpu nodes to be present and contain the properties -described below. - -- cpus node - - Description: Container of cpu nodes - - The node name must be "cpus". - - A cpus node must define the following properties: - - - #address-cells - Usage: required - Value type: <u32> - - Definition depends on ARM architecture version and - configuration: - - # On uniprocessor ARM architectures previous to v7 - value must be 1, to enable a simple enumeration - scheme for processors that do not have a HW CPU - identification register. - # On 32-bit ARM 11 MPcore, ARM v7 or later systems - value must be 1, that corresponds to CPUID/MPIDR - registers sizes. - # On ARM v8 64-bit systems value should be set to 2, - that corresponds to the MPIDR_EL1 register size. - If MPIDR_EL1[63:32] value is equal to 0 on all CPUs - in the system, #address-cells can be set to 1, since - MPIDR_EL1[63:32] bits are not used for CPUs - identification. - - #size-cells - Usage: required - Value type: <u32> - Definition: must be set to 0 - -- cpu node - - Description: Describes a CPU in an ARM based system - - PROPERTIES - - - device_type - Usage: required - Value type: <string> - Definition: must be "cpu" - - reg - Usage and definition depend on ARM architecture version and - configuration: - - # On uniprocessor ARM architectures previous to v7 - this property is required and must be set to 0. - - # On ARM 11 MPcore based systems this property is - required and matches the CPUID[11:0] register bits. - - Bits [11:0] in the reg cell must be set to - bits [11:0] in CPU ID register. - - All other bits in the reg cell must be set to 0. - - # On 32-bit ARM v7 or later systems this property is - required and matches the CPU MPIDR[23:0] register - bits. - - Bits [23:0] in the reg cell must be set to - bits [23:0] in MPIDR. - - All other bits in the reg cell must be set to 0. - - # On ARM v8 64-bit systems this property is required - and matches the MPIDR_EL1 register affinity bits. - - * If cpus node's #address-cells property is set to 2 - - The first reg cell bits [7:0] must be set to - bits [39:32] of MPIDR_EL1. - - The second reg cell bits [23:0] must be set to - bits [23:0] of MPIDR_EL1. - - * If cpus node's #address-cells property is set to 1 - - The reg cell bits [23:0] must be set to bits [23:0] - of MPIDR_EL1. - - All other bits in the reg cells must be set to 0. - - - compatible: - Usage: required - Value type: <string> - Definition: should be one of: - "arm,arm710t" - "arm,arm720t" - "arm,arm740t" - "arm,arm7ej-s" - "arm,arm7tdmi" - "arm,arm7tdmi-s" - "arm,arm9es" - "arm,arm9ej-s" - "arm,arm920t" - "arm,arm922t" - "arm,arm925" - "arm,arm926e-s" - "arm,arm926ej-s" - "arm,arm940t" - "arm,arm946e-s" - "arm,arm966e-s" - "arm,arm968e-s" - "arm,arm9tdmi" - "arm,arm1020e" - "arm,arm1020t" - "arm,arm1022e" - "arm,arm1026ej-s" - "arm,arm1136j-s" - "arm,arm1136jf-s" - "arm,arm1156t2-s" - "arm,arm1156t2f-s" - "arm,arm1176jzf" - "arm,arm1176jz-s" - "arm,arm1176jzf-s" - "arm,arm11mpcore" - "arm,cortex-a5" - "arm,cortex-a7" - "arm,cortex-a8" - "arm,cortex-a9" - "arm,cortex-a12" - "arm,cortex-a15" - "arm,cortex-a17" - "arm,cortex-a53" - "arm,cortex-a57" - "arm,cortex-a72" - "arm,cortex-a73" - "arm,cortex-m0" - "arm,cortex-m0+" - "arm,cortex-m1" - "arm,cortex-m3" - "arm,cortex-m4" - "arm,cortex-r4" - "arm,cortex-r5" - "arm,cortex-r7" - "brcm,brahma-b15" - "brcm,brahma-b53" - "brcm,vulcan" - "cavium,thunder" - "cavium,thunder2" - "faraday,fa526" - "intel,sa110" - "intel,sa1100" - "marvell,feroceon" - "marvell,mohawk" - "marvell,pj4a" - "marvell,pj4b" - "marvell,sheeva-v5" - "nvidia,tegra132-denver" - "nvidia,tegra186-denver" - "nvidia,tegra194-carmel" - "qcom,krait" - "qcom,kryo" - "qcom,kryo385" - "qcom,scorpion" - - enable-method - Value type: <stringlist> - Usage and definition depend on ARM architecture version. - # On ARM v8 64-bit this property is required and must - be one of: - "psci" - "spin-table" - # On ARM 32-bit systems this property is optional and - can be one of: - "actions,s500-smp" - "allwinner,sun6i-a31" - "allwinner,sun8i-a23" - "allwinner,sun9i-a80-smp" - "amlogic,meson8-smp" - "amlogic,meson8b-smp" - "arm,realview-smp" - "brcm,bcm11351-cpu-method" - "brcm,bcm23550" - "brcm,bcm2836-smp" - "brcm,bcm-nsp-smp" - "brcm,brahma-b15" - "marvell,armada-375-smp" - "marvell,armada-380-smp" - "marvell,armada-390-smp" - "marvell,armada-xp-smp" - "marvell,98dx3236-smp" - "mediatek,mt6589-smp" - "mediatek,mt81xx-tz-smp" - "qcom,gcc-msm8660" - "qcom,kpss-acc-v1" - "qcom,kpss-acc-v2" - "renesas,apmu" - "renesas,r9a06g032-smp" - "rockchip,rk3036-smp" - "rockchip,rk3066-smp" - "ste,dbx500-smp" - - - cpu-release-addr - Usage: required for systems that have an "enable-method" - property value of "spin-table". - Value type: <prop-encoded-array> - Definition: - # On ARM v8 64-bit systems must be a two cell - property identifying a 64-bit zero-initialised - memory location. - - - qcom,saw - Usage: required for systems that have an "enable-method" - property value of "qcom,kpss-acc-v1" or - "qcom,kpss-acc-v2" - Value type: <phandle> - Definition: Specifies the SAW[1] node associated with this CPU. - - - qcom,acc - Usage: required for systems that have an "enable-method" - property value of "qcom,kpss-acc-v1" or - "qcom,kpss-acc-v2" - Value type: <phandle> - Definition: Specifies the ACC[2] node associated with this CPU. - - - cpu-idle-states - Usage: Optional - Value type: <prop-encoded-array> - Definition: - # List of phandles to idle state nodes supported - by this cpu [3]. - - - capacity-dmips-mhz - Usage: Optional - Value type: <u32> - Definition: - # u32 value representing CPU capacity [4] in - DMIPS/MHz, relative to highest capacity-dmips-mhz - in the system. - - - rockchip,pmu - Usage: optional for systems that have an "enable-method" - property value of "rockchip,rk3066-smp" - While optional, it is the preferred way to get access to - the cpu-core power-domains. - Value type: <phandle> - Definition: Specifies the syscon node controlling the cpu core - power domains. - - - dynamic-power-coefficient - Usage: optional - Value type: <prop-encoded-array> - Definition: A u32 value that represents the running time dynamic - power coefficient in units of uW/MHz/V^2. The - coefficient can either be calculated from power - measurements or derived by analysis. - - The dynamic power consumption of the CPU is - proportional to the square of the Voltage (V) and - the clock frequency (f). The coefficient is used to - calculate the dynamic power as below - - - Pdyn = dynamic-power-coefficient * V^2 * f - - where voltage is in V, frequency is in MHz. - -Example 1 (dual-cluster big.LITTLE system 32-bit): - - cpus { - #size-cells = <0>; - #address-cells = <1>; - - cpu@0 { - device_type = "cpu"; - compatible = "arm,cortex-a15"; - reg = <0x0>; - }; - - cpu@1 { - device_type = "cpu"; - compatible = "arm,cortex-a15"; - reg = <0x1>; - }; - - cpu@100 { - device_type = "cpu"; - compatible = "arm,cortex-a7"; - reg = <0x100>; - }; - - cpu@101 { - device_type = "cpu"; - compatible = "arm,cortex-a7"; - reg = <0x101>; - }; - }; - -Example 2 (Cortex-A8 uniprocessor 32-bit system): - - cpus { - #size-cells = <0>; - #address-cells = <1>; - - cpu@0 { - device_type = "cpu"; - compatible = "arm,cortex-a8"; - reg = <0x0>; - }; - }; - -Example 3 (ARM 926EJ-S uniprocessor 32-bit system): - - cpus { - #size-cells = <0>; - #address-cells = <1>; - - cpu@0 { - device_type = "cpu"; - compatible = "arm,arm926ej-s"; - reg = <0x0>; - }; - }; - -Example 4 (ARM Cortex-A57 64-bit system): - -cpus { - #size-cells = <0>; - #address-cells = <2>; - - cpu@0 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x0 0x0>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@1 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x0 0x1>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@100 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x0 0x100>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@101 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x0 0x101>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@10000 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x0 0x10000>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@10001 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x0 0x10001>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@10100 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x0 0x10100>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@10101 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x0 0x10101>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@100000000 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x1 0x0>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@100000001 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x1 0x1>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@100000100 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x1 0x100>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@100000101 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x1 0x101>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@100010000 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x1 0x10000>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@100010001 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x1 0x10001>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@100010100 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x1 0x10100>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; - - cpu@100010101 { - device_type = "cpu"; - compatible = "arm,cortex-a57"; - reg = <0x1 0x10101>; - enable-method = "spin-table"; - cpu-release-addr = <0 0x20000000>; - }; -}; - --- -[1] arm/msm/qcom,saw2.txt -[2] arm/msm/qcom,kpss-acc.txt -[3] ARM Linux kernel documentation - idle states bindings - Documentation/devicetree/bindings/arm/idle-states.txt -[4] ARM Linux kernel documentation - cpu capacity bindings - Documentation/devicetree/bindings/arm/cpu-capacity.txt diff --git a/Documentation/devicetree/bindings/arm/cpus.yaml b/Documentation/devicetree/bindings/arm/cpus.yaml new file mode 100644 index 000000000000..298c17b327c6 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/cpus.yaml @@ -0,0 +1,507 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/cpus.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: ARM CPUs bindings + +maintainers: + - Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> + +description: |+ + The device tree allows to describe the layout of CPUs in a system through + the "cpus" node, which in turn contains a number of subnodes (ie "cpu") + defining properties for every cpu. + + Bindings for CPU nodes follow the Devicetree Specification, available from: + + https://www.devicetree.org/specifications/ + + with updates for 32-bit and 64-bit ARM systems provided in this document. + + ================================ + Convention used in this document + ================================ + + This document follows the conventions described in the Devicetree + Specification, with the addition: + + - square brackets define bitfields, eg reg[7:0] value of the bitfield in + the reg property contained in bits 7 down to 0 + + ===================================== + cpus and cpu node bindings definition + ===================================== + + The ARM architecture, in accordance with the Devicetree Specification, + requires the cpus and cpu nodes to be present and contain the properties + described below. + +properties: + $nodename: + const: cpus + description: Container of cpu nodes + + '#address-cells': + enum: [1, 2] + description: | + Definition depends on ARM architecture version and configuration: + + On uniprocessor ARM architectures previous to v7 + value must be 1, to enable a simple enumeration + scheme for processors that do not have a HW CPU + identification register. + On 32-bit ARM 11 MPcore, ARM v7 or later systems + value must be 1, that corresponds to CPUID/MPIDR + registers sizes. + On ARM v8 64-bit systems value should be set to 2, + that corresponds to the MPIDR_EL1 register size. + If MPIDR_EL1[63:32] value is equal to 0 on all CPUs + in the system, #address-cells can be set to 1, since + MPIDR_EL1[63:32] bits are not used for CPUs + identification. + + '#size-cells': + const: 0 + +patternProperties: + '^cpu@[0-9a-f]+$': + properties: + device_type: + const: cpu + + reg: + maxItems: 1 + description: | + Usage and definition depend on ARM architecture version and + configuration: + + On uniprocessor ARM architectures previous to v7 + this property is required and must be set to 0. + + On ARM 11 MPcore based systems this property is + required and matches the CPUID[11:0] register bits. + + Bits [11:0] in the reg cell must be set to + bits [11:0] in CPU ID register. + + All other bits in the reg cell must be set to 0. + + On 32-bit ARM v7 or later systems this property is + required and matches the CPU MPIDR[23:0] register + bits. + + Bits [23:0] in the reg cell must be set to + bits [23:0] in MPIDR. + + All other bits in the reg cell must be set to 0. + + On ARM v8 64-bit systems this property is required + and matches the MPIDR_EL1 register affinity bits. + + * If cpus node's #address-cells property is set to 2 + + The first reg cell bits [7:0] must be set to + bits [39:32] of MPIDR_EL1. + + The second reg cell bits [23:0] must be set to + bits [23:0] of MPIDR_EL1. + + * If cpus node's #address-cells property is set to 1 + + The reg cell bits [23:0] must be set to bits [23:0] + of MPIDR_EL1. + + All other bits in the reg cells must be set to 0. + + compatible: + items: + - enum: + - arm,arm710t + - arm,arm720t + - arm,arm740t + - arm,arm7ej-s + - arm,arm7tdmi + - arm,arm7tdmi-s + - arm,arm9es + - arm,arm9ej-s + - arm,arm920t + - arm,arm922t + - arm,arm925 + - arm,arm926e-s + - arm,arm926ej-s + - arm,arm940t + - arm,arm946e-s + - arm,arm966e-s + - arm,arm968e-s + - arm,arm9tdmi + - arm,arm1020e + - arm,arm1020t + - arm,arm1022e + - arm,arm1026ej-s + - arm,arm1136j-s + - arm,arm1136jf-s + - arm,arm1156t2-s + - arm,arm1156t2f-s + - arm,arm1176jzf + - arm,arm1176jz-s + - arm,arm1176jzf-s + - arm,arm11mpcore + - arm,armv8 # Only for s/w models + - arm,cortex-a5 + - arm,cortex-a7 + - arm,cortex-a8 + - arm,cortex-a9 + - arm,cortex-a12 + - arm,cortex-a15 + - arm,cortex-a17 + - arm,cortex-a53 + - arm,cortex-a57 + - arm,cortex-a72 + - arm,cortex-a73 + - arm,cortex-m0 + - arm,cortex-m0+ + - arm,cortex-m1 + - arm,cortex-m3 + - arm,cortex-m4 + - arm,cortex-r4 + - arm,cortex-r5 + - arm,cortex-r7 + - brcm,brahma-b15 + - brcm,brahma-b53 + - brcm,vulcan + - cavium,thunder + - cavium,thunder2 + - faraday,fa526 + - intel,sa110 + - intel,sa1100 + - marvell,feroceon + - marvell,mohawk + - marvell,pj4a + - marvell,pj4b + - marvell,sheeva-v5 + - marvell,sheeva-v7 + - nvidia,tegra132-denver + - nvidia,tegra186-denver + - nvidia,tegra194-carmel + - qcom,krait + - qcom,kryo + - qcom,kryo385 + - qcom,scorpion + + enable-method: + allOf: + - $ref: '/schemas/types.yaml#/definitions/string' + - oneOf: + # On ARM v8 64-bit this property is required + - enum: + - psci + - spin-table + # On ARM 32-bit systems this property is optional + - enum: + - actions,s500-smp + - allwinner,sun6i-a31 + - allwinner,sun8i-a23 + - allwinner,sun9i-a80-smp + - allwinner,sun8i-a83t-smp + - amlogic,meson8-smp + - amlogic,meson8b-smp + - arm,realview-smp + - brcm,bcm11351-cpu-method + - brcm,bcm23550 + - brcm,bcm2836-smp + - brcm,bcm63138 + - brcm,bcm-nsp-smp + - brcm,brahma-b15 + - marvell,armada-375-smp + - marvell,armada-380-smp + - marvell,armada-390-smp + - marvell,armada-xp-smp + - marvell,98dx3236-smp + - mediatek,mt6589-smp + - mediatek,mt81xx-tz-smp + - qcom,gcc-msm8660 + - qcom,kpss-acc-v1 + - qcom,kpss-acc-v2 + - renesas,apmu + - renesas,r9a06g032-smp + - rockchip,rk3036-smp + - rockchip,rk3066-smp + - ste,dbx500-smp + + cpu-release-addr: + $ref: '/schemas/types.yaml#/definitions/uint64' + + description: + Required for systems that have an "enable-method" + property value of "spin-table". + On ARM v8 64-bit systems must be a two cell + property identifying a 64-bit zero-initialised + memory location. + + cpu-idle-states: + $ref: '/schemas/types.yaml#/definitions/phandle-array' + description: | + List of phandles to idle state nodes supported + by this cpu (see ./idle-states.txt). + + capacity-dmips-mhz: + $ref: '/schemas/types.yaml#/definitions/uint32' + description: + u32 value representing CPU capacity (see ./cpu-capacity.txt) in + DMIPS/MHz, relative to highest capacity-dmips-mhz + in the system. + + dynamic-power-coefficient: + $ref: '/schemas/types.yaml#/definitions/uint32' + description: + A u32 value that represents the running time dynamic + power coefficient in units of uW/MHz/V^2. The + coefficient can either be calculated from power + measurements or derived by analysis. + + The dynamic power consumption of the CPU is + proportional to the square of the Voltage (V) and + the clock frequency (f). The coefficient is used to + calculate the dynamic power as below - + + Pdyn = dynamic-power-coefficient * V^2 * f + + where voltage is in V, frequency is in MHz. + + qcom,saw: + $ref: '/schemas/types.yaml#/definitions/phandle' + description: | + Specifies the SAW* node associated with this CPU. + + Required for systems that have an "enable-method" property + value of "qcom,kpss-acc-v1" or "qcom,kpss-acc-v2" + + * arm/msm/qcom,saw2.txt + + qcom,acc: + $ref: '/schemas/types.yaml#/definitions/phandle' + description: | + Specifies the ACC* node associated with this CPU. + + Required for systems that have an "enable-method" property + value of "qcom,kpss-acc-v1" or "qcom,kpss-acc-v2" + + * arm/msm/qcom,kpss-acc.txt + + rockchip,pmu: + $ref: '/schemas/types.yaml#/definitions/phandle' + description: | + Specifies the syscon node controlling the cpu core power domains. + + Optional for systems that have an "enable-method" + property value of "rockchip,rk3066-smp" + While optional, it is the preferred way to get access to + the cpu-core power-domains. + + required: + - device_type + - reg + - compatible + + dependencies: + cpu-release-addr: [enable-method] + rockchip,pmu: [enable-method] + +required: + - '#address-cells' + - '#size-cells' + +examples: + - | + cpus { + #size-cells = <0>; + #address-cells = <1>; + + cpu@0 { + device_type = "cpu"; + compatible = "arm,cortex-a15"; + reg = <0x0>; + }; + + cpu@1 { + device_type = "cpu"; + compatible = "arm,cortex-a15"; + reg = <0x1>; + }; + + cpu@100 { + device_type = "cpu"; + compatible = "arm,cortex-a7"; + reg = <0x100>; + }; + + cpu@101 { + device_type = "cpu"; + compatible = "arm,cortex-a7"; + reg = <0x101>; + }; + }; + + - | + // Example 2 (Cortex-A8 uniprocessor 32-bit system): + cpus { + #size-cells = <0>; + #address-cells = <1>; + + cpu@0 { + device_type = "cpu"; + compatible = "arm,cortex-a8"; + reg = <0x0>; + }; + }; + + - | + // Example 3 (ARM 926EJ-S uniprocessor 32-bit system): + cpus { + #size-cells = <0>; + #address-cells = <1>; + + cpu@0 { + device_type = "cpu"; + compatible = "arm,arm926ej-s"; + reg = <0x0>; + }; + }; + + - | + // Example 4 (ARM Cortex-A57 64-bit system): + cpus { + #size-cells = <0>; + #address-cells = <2>; + + cpu@0 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x0 0x0>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@1 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x0 0x1>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@100 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x0 0x100>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@101 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x0 0x101>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@10000 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x0 0x10000>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@10001 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x0 0x10001>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@10100 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x0 0x10100>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@10101 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x0 0x10101>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@100000000 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x1 0x0>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@100000001 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x1 0x1>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@100000100 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x1 0x100>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@100000101 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x1 0x101>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@100010000 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x1 0x10000>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@100010001 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x1 0x10001>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@100010100 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x1 0x10100>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + + cpu@100010101 { + device_type = "cpu"; + compatible = "arm,cortex-a57"; + reg = <0x1 0x10101>; + enable-method = "spin-table"; + cpu-release-addr = <0 0x20000000>; + }; + }; +... diff --git a/Documentation/devicetree/bindings/arm/davinci.txt b/Documentation/devicetree/bindings/arm/davinci.txt deleted file mode 100644 index 715622c36260..000000000000 --- a/Documentation/devicetree/bindings/arm/davinci.txt +++ /dev/null @@ -1,25 +0,0 @@ -Texas Instruments DaVinci Platforms Device Tree Bindings --------------------------------------------------------- - -DA850/OMAP-L138/AM18x Evaluation Module (EVM) board -Required root node properties: - - compatible = "ti,da850-evm", "ti,da850"; - -DA850/OMAP-L138/AM18x L138/C6748 Development Kit (LCDK) board -Required root node properties: - - compatible = "ti,da850-lcdk", "ti,da850"; - -EnBW AM1808 based CMC board -Required root node properties: - - compatible = "enbw,cmc", "ti,da850; - -LEGO MINDSTORMS EV3 (AM1808 based) -Required root node properties: - - compatible = "lego,ev3", "ti,da850"; - -Generic DaVinci Boards ----------------------- - -DA850/OMAP-L138/AM18x generic board -Required root node properties: - - compatible = "ti,da850"; diff --git a/Documentation/devicetree/bindings/arm/emtrion.txt b/Documentation/devicetree/bindings/arm/emtrion.txt new file mode 100644 index 000000000000..83329aefc483 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/emtrion.txt @@ -0,0 +1,12 @@ +Emtrion Devicetree Bindings +=========================== + +emCON Series: +------------- + +Required root node properties + - compatible: + - "emtrion,emcon-mx6", "fsl,imx6q"; : emCON-MX6D or emCON-MX6Q SoM + - "emtrion,emcon-mx6-avari", "fsl,imx6q"; : emCON-MX6D or emCON-MX6Q SoM on Avari Base + - "emtrion,emcon-mx6", "fsl,imx6dl"; : emCON-MX6S or emCON-MX6DL SoM + - "emtrion,emcon-mx6-avari", "fsl,imx6dl"; : emCON-MX6S or emCON-MX6DL SoM on Avari Base diff --git a/Documentation/devicetree/bindings/arm/freescale/fsl,imx7ulp-pm.txt b/Documentation/devicetree/bindings/arm/freescale/fsl,imx7ulp-pm.txt new file mode 100644 index 000000000000..75195bee116f --- /dev/null +++ b/Documentation/devicetree/bindings/arm/freescale/fsl,imx7ulp-pm.txt @@ -0,0 +1,23 @@ +Freescale i.MX7ULP Power Management Components +---------------------------------------------- + +The Multi-System Mode Controller (MSMC) is responsible for sequencing +the MCU into and out of all stop and run power modes. Specifically, it +monitors events to trigger transitions between power modes while +controlling the power, clocks, and memories of the MCU to achieve the +power consumption and functionality of that mode. + +The WFI or WFE instruction is used to invoke a Sleep, Deep Sleep or +Standby modes for either Cortex family. Run, Wait, and Stop are the +common terms used for the primary operating modes of Kinetis +microcontrollers. + +Required properties: +- compatible: Should be "fsl,imx7ulp-smc1". +- reg: Specifies base physical address and size of the register sets. + +Example: +smc1: smc1@40410000 { + compatible = "fsl,imx7ulp-smc1"; + reg = <0x40410000 0x1000>; +}; diff --git a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt index c20f38e56544..27784b6edfed 100644 --- a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt +++ b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt @@ -88,13 +88,16 @@ Pinctrl bindings based on SCU Message Protocol This binding uses the i.MX common pinctrl binding[3]. Required properties: -- compatible: Should be "fsl,imx8qxp-iomuxc". +- compatible: Should be one of: + "fsl,imx8qm-iomuxc", + "fsl,imx8qxp-iomuxc". Required properties for Pinctrl sub nodes: - fsl,pins: Each entry consists of 3 integers which represents the mux and config setting for one pin. The first 2 integers <pin_id mux_mode> are specified using a PIN_FUNC_ID macro, which can be found in + <dt-bindings/pinctrl/pads-imx8qm.h>, <dt-bindings/pinctrl/pads-imx8qxp.h>. The last integer CONFIG is the pad setting value like pull-up on this pin. @@ -106,6 +109,12 @@ Required properties for Pinctrl sub nodes: [2] Documentation/devicetree/bindings/power/power_domain.txt [3] Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt +RTC bindings based on SCU Message Protocol +------------------------------------------------------------ + +Required properties: +- compatible: should be "fsl,imx8qxp-sc-rtc"; + Example (imx8qxp): ------------- lsio_mu1: mailbox@5d1c0000 { @@ -148,6 +157,10 @@ firmware { compatible = "fsl,imx8qxp-scu-pd"; #power-domain-cells = <1>; }; + + rtc: rtc { + compatible = "fsl,imx8qxp-sc-rtc"; + }; }; }; diff --git a/Documentation/devicetree/bindings/arm/fsl.txt b/Documentation/devicetree/bindings/arm/fsl.txt index 5074aeecd327..7fbc42484001 100644 --- a/Documentation/devicetree/bindings/arm/fsl.txt +++ b/Documentation/devicetree/bindings/arm/fsl.txt @@ -101,6 +101,10 @@ i.MX7 SabreSD Board Required root node properties: - compatible = "fsl,imx7d-sdb", "fsl,imx7d"; +i.MX7ULP Evaluation Kit +Required root node properties: + - compatible = "fsl,imx7ulp-evk", "fsl,imx7ulp"; + Generic i.MX boards ------------------- @@ -123,6 +127,10 @@ i.MX6q generic board Required root node properties: - compatible = "fsl,imx6q"; +i.MX7ULP generic board +Required root node properties: + - compatible = "fsl,imx7ulp"; + Freescale Vybrid Platform Device Tree Bindings ---------------------------------------------- diff --git a/Documentation/devicetree/bindings/arm/idle-states.txt b/Documentation/devicetree/bindings/arm/idle-states.txt index 2c73847499ab..8f0937db55c5 100644 --- a/Documentation/devicetree/bindings/arm/idle-states.txt +++ b/Documentation/devicetree/bindings/arm/idle-states.txt @@ -142,7 +142,7 @@ characterised by the following graph: The graph is split in two parts delimited by time 1ms on the X-axis. The graph curve with X-axis values = { x | 0 < x < 1ms } has a steep slope -and denotes the energy costs incurred whilst entering and leaving the idle +and denotes the energy costs incurred while entering and leaving the idle state. The graph curve in the area delimited by X-axis values = {x | x > 1ms } has shallower slope and essentially represents the energy consumption of the idle diff --git a/Documentation/devicetree/bindings/arm/mrvl/mrvl.txt b/Documentation/devicetree/bindings/arm/mrvl/mrvl.txt index 117d741a2e4f..951687528efb 100644 --- a/Documentation/devicetree/bindings/arm/mrvl/mrvl.txt +++ b/Documentation/devicetree/bindings/arm/mrvl/mrvl.txt @@ -11,4 +11,4 @@ Required root node properties: MMP2 Brownstone Board Required root node properties: - - compatible = "mrvl,mmp2-brownstone"; + - compatible = "mrvl,mmp2-brownstone", "mrvl,mmp2"; diff --git a/Documentation/devicetree/bindings/arm/nspire.txt b/Documentation/devicetree/bindings/arm/nspire.txt deleted file mode 100644 index 4d08518bd176..000000000000 --- a/Documentation/devicetree/bindings/arm/nspire.txt +++ /dev/null @@ -1,14 +0,0 @@ -TI-NSPIRE calculators - -Required properties: -- compatible: Compatible property value should contain "ti,nspire". - CX models should have "ti,nspire-cx" - Touchpad models should have "ti,nspire-tp" - Clickpad models should have "ti,nspire-clp" - -Example: - -/ { - model = "TI-NSPIRE CX"; - compatible = "ti,nspire-cx"; - ... diff --git a/Documentation/devicetree/bindings/arm/primecell.txt b/Documentation/devicetree/bindings/arm/primecell.txt deleted file mode 100644 index 0df6acacfaea..000000000000 --- a/Documentation/devicetree/bindings/arm/primecell.txt +++ /dev/null @@ -1,46 +0,0 @@ -* ARM Primecell Peripherals - -ARM, Ltd. Primecell peripherals have a standard id register that can be used to -identify the peripheral type, vendor, and revision. This value can be used for -driver matching. - -Required properties: - -- compatible : should be a specific name for the peripheral and - "arm,primecell". The specific name will match the ARM - engineering name for the logic block in the form: "arm,pl???" - -Optional properties: - -- arm,primecell-periphid : Value to override the h/w value with -- clocks : From common clock binding. First clock is phandle to clock for apb - pclk. Additional clocks are optional and specific to those peripherals. -- clock-names : From common clock binding. Shall be "apb_pclk" for first clock. -- dmas : From common DMA binding. If present, refers to one or more dma channels. -- dma-names : From common DMA binding, needs to match the 'dmas' property. - Devices with exactly one receive and transmit channel shall name - these "rx" and "tx", respectively. -- pinctrl-<n> : Pinctrl states as described in bindings/pinctrl/pinctrl-bindings.txt -- pinctrl-names : Names corresponding to the numbered pinctrl states -- interrupts : one or more interrupt specifiers -- interrupt-names : names corresponding to the interrupts properties - -Example: - -serial@fff36000 { - compatible = "arm,pl011", "arm,primecell"; - arm,primecell-periphid = <0x00341011>; - - clocks = <&pclk>; - clock-names = "apb_pclk"; - - dmas = <&dma-controller 4>, <&dma-controller 5>; - dma-names = "rx", "tx"; - - pinctrl-0 = <&uart0_default_mux>, <&uart0_default_mode>; - pinctrl-1 = <&uart0_sleep_mode>; - pinctrl-names = "default","sleep"; - - interrupts = <0 11 0x4>; -}; - diff --git a/Documentation/devicetree/bindings/arm/primecell.yaml b/Documentation/devicetree/bindings/arm/primecell.yaml new file mode 100644 index 000000000000..5aae37f1c563 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/primecell.yaml @@ -0,0 +1,36 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/primecell.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: ARM Primecell Peripherals + +maintainers: + - Rob Herring <robh@kernel.org> + +description: |+ + ARM, Ltd. Primecell peripherals have a standard id register that can be used to + identify the peripheral type, vendor, and revision. This value can be used for + driver matching. + +properties: + compatible: + contains: + const: arm,primecell + description: + Should be a specific name for the peripheral followed by "arm,primecell". + The specific name will match the ARM engineering name for the logic block + in the form "arm,pl???" + + arm,primecell-periphid: + $ref: /schemas/types.yaml#/definitions/uint32 + description: Value to override the h/w ID value + clocks: + minItems: 1 + maxItems: 32 + clock-names: + contains: + const: apb_pclk + additionalItems: true +... diff --git a/Documentation/devicetree/bindings/arm/qcom.txt b/Documentation/devicetree/bindings/arm/qcom.txt deleted file mode 100644 index ee532e705d6c..000000000000 --- a/Documentation/devicetree/bindings/arm/qcom.txt +++ /dev/null @@ -1,57 +0,0 @@ -QCOM device tree bindings -------------------------- - -Some qcom based bootloaders identify the dtb blob based on a set of -device properties like SoC and platform and revisions of those components. -To support this scheme, we encode this information into the board compatible -string. - -Each board must specify a top-level board compatible string with the following -format: - - compatible = "qcom,<SoC>[-<soc_version>][-<foundry_id>]-<board>[/<subtype>][-<board_version>]" - -The 'SoC' and 'board' elements are required. All other elements are optional. - -The 'SoC' element must be one of the following strings: - - apq8016 - apq8074 - apq8084 - apq8096 - msm8916 - msm8974 - msm8992 - msm8994 - msm8996 - mdm9615 - ipq8074 - sdm845 - -The 'board' element must be one of the following strings: - - cdp - liquid - dragonboard - mtp - sbc - hk01 - -The 'soc_version' and 'board_version' elements take the form of v<Major>.<Minor> -where the minor number may be omitted when it's zero, i.e. v1.0 is the same -as v1. If all versions of the 'board_version' elements match, then a -wildcard '*' should be used, e.g. 'v*'. - -The 'foundry_id' and 'subtype' elements are one or more digits from 0 to 9. - -Examples: - - "qcom,msm8916-v1-cdp-pm8916-v2.1" - -A CDP board with an msm8916 SoC, version 1 paired with a pm8916 PMIC of version -2.1. - - "qcom,apq8074-v2.0-2-dragonboard/1-v0.1" - -A dragonboard board v0.1 of subtype 1 with an apq8074 SoC version 2, made in -foundry 2. diff --git a/Documentation/devicetree/bindings/arm/qcom.yaml b/Documentation/devicetree/bindings/arm/qcom.yaml new file mode 100644 index 000000000000..f6316ab66385 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/qcom.yaml @@ -0,0 +1,125 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/bindings/arm/qcom.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: QCOM device tree bindings + +maintainers: + - Stephen Boyd <sboyd@codeaurora.org> + +description: | + Some qcom based bootloaders identify the dtb blob based on a set of + device properties like SoC and platform and revisions of those components. + To support this scheme, we encode this information into the board compatible + string. + + Each board must specify a top-level board compatible string with the following + format: + + compatible = "qcom,<SoC>[-<soc_version>][-<foundry_id>]-<board>[/<subtype>][-<board_version>]" + + The 'SoC' and 'board' elements are required. All other elements are optional. + + The 'SoC' element must be one of the following strings: + + apq8016 + apq8074 + apq8084 + apq8096 + msm8916 + msm8974 + msm8992 + msm8994 + msm8996 + mdm9615 + ipq8074 + sdm845 + + The 'board' element must be one of the following strings: + + cdp + liquid + dragonboard + mtp + sbc + hk01 + + The 'soc_version' and 'board_version' elements take the form of v<Major>.<Minor> + where the minor number may be omitted when it's zero, i.e. v1.0 is the same + as v1. If all versions of the 'board_version' elements match, then a + wildcard '*' should be used, e.g. 'v*'. + + The 'foundry_id' and 'subtype' elements are one or more digits from 0 to 9. + + Examples: + + "qcom,msm8916-v1-cdp-pm8916-v2.1" + + A CDP board with an msm8916 SoC, version 1 paired with a pm8916 PMIC of version + 2.1. + + "qcom,apq8074-v2.0-2-dragonboard/1-v0.1" + + A dragonboard board v0.1 of subtype 1 with an apq8074 SoC version 2, made in + foundry 2. + +properties: + compatible: + oneOf: + - items: + - enum: + - qcom,apq8016-sbc + - const: qcom,apq8016 + + - items: + - enum: + - qcom,apq8064-cm-qs600 + - qcom,apq8064-ifc6410 + - const: qcom,apq8064 + + - items: + - enum: + - qcom,apq8074-dragonboard + - const: qcom,apq8074 + + - items: + - enum: + - qcom,apq8060-dragonboard + - qcom,msm8660-surf + - const: qcom,msm8660 + + - items: + - enum: + - qcom,apq8084-mtp + - qcom,apq8084-sbc + - const: qcom,apq8084 + + - items: + - enum: + - qcom,msm8960-cdp + - const: qcom,msm8960 + + - items: + - const: qcom,msm8916-mtp/1 + - const: qcom,msm8916-mtp + - const: qcom,msm8916 + + - items: + - const: qcom,msm8996-mtp + + - items: + - const: qcom,ipq4019 + + - items: + - enum: + - qcom,ipq8064-ap148 + - const: qcom,ipq8064 + + - items: + - enum: + - qcom,ipq8074-hk01 + - const: qcom,ipq8074 + +... diff --git a/Documentation/devicetree/bindings/arm/renesas,prr.txt b/Documentation/devicetree/bindings/arm/renesas,prr.txt new file mode 100644 index 000000000000..08e482e953ca --- /dev/null +++ b/Documentation/devicetree/bindings/arm/renesas,prr.txt @@ -0,0 +1,20 @@ +Renesas Product Register + +Most Renesas ARM SoCs have a Product Register or Boundary Scan ID Register that +allows to retrieve SoC product and revision information. If present, a device +node for this register should be added. + +Required properties: + - compatible: Must be one of: + "renesas,prr" + "renesas,bsid" + - reg: Base address and length of the register block. + + +Examples +-------- + + prr: chipid@ff000044 { + compatible = "renesas,prr"; + reg = <0 0xff000044 0 4>; + }; diff --git a/Documentation/devicetree/bindings/arm/rockchip.txt b/Documentation/devicetree/bindings/arm/rockchip.txt deleted file mode 100644 index 0cc71236d639..000000000000 --- a/Documentation/devicetree/bindings/arm/rockchip.txt +++ /dev/null @@ -1,240 +0,0 @@ -Rockchip platforms device tree bindings ---------------------------------------- - -- 96boards RK3399 Ficus (ROCK960 Enterprise Edition) - Required root node properties: - - compatible = "vamrs,ficus", "rockchip,rk3399"; - -- 96boards RK3399 Rock960 (ROCK960 Consumer Edition) - Required root node properties: - - compatible = "vamrs,rock960", "rockchip,rk3399"; - -- Amarula Vyasa RK3288 board - Required root node properties: - - compatible = "amarula,vyasa-rk3288", "rockchip,rk3288"; - -- Asus Tinker board - Required root node properties: - - compatible = "asus,rk3288-tinker", "rockchip,rk3288"; - -- Asus Tinker board S - Required root node properties: - - compatible = "asus,rk3288-tinker-s", "rockchip,rk3288"; - -- Kylin RK3036 board: - Required root node properties: - - compatible = "rockchip,kylin-rk3036", "rockchip,rk3036"; - -- MarsBoard RK3066 board: - Required root node properties: - - compatible = "haoyu,marsboard-rk3066", "rockchip,rk3066a"; - -- bq Curie 2 tablet: - Required root node properties: - - compatible = "mundoreader,bq-curie2", "rockchip,rk3066a"; - -- ChipSPARK Rayeager PX2 board: - Required root node properties: - - compatible = "chipspark,rayeager-px2", "rockchip,rk3066a"; - -- Radxa Rock board: - Required root node properties: - - compatible = "radxa,rock", "rockchip,rk3188"; - -- Radxa Rock2 Square board: - Required root node properties: - - compatible = "radxa,rock2-square", "rockchip,rk3288"; - -- Rikomagic MK808 v1 board: - Required root node properties: - - compatible = "rikomagic,mk808", "rockchip,rk3066a"; - -- Firefly Firefly-RK3288 board: - Required root node properties: - - compatible = "firefly,firefly-rk3288", "rockchip,rk3288"; - or - - compatible = "firefly,firefly-rk3288-beta", "rockchip,rk3288"; - -- Firefly Firefly-RK3288 Reload board: - Required root node properties: - - compatible = "firefly,firefly-rk3288-reload", "rockchip,rk3288"; - -- Firefly Firefly-RK3399 board: - Required root node properties: - - compatible = "firefly,firefly-rk3399", "rockchip,rk3399"; - -- Firefly roc-rk3328-cc board: - Required root node properties: - - compatible = "firefly,roc-rk3328-cc", "rockchip,rk3328"; - -- Firefly ROC-RK3399-PC board: - Required root node properties: - - compatible = "firefly,roc-rk3399-pc", "rockchip,rk3399"; - -- ChipSPARK PopMetal-RK3288 board: - Required root node properties: - - compatible = "chipspark,popmetal-rk3288", "rockchip,rk3288"; - -- Netxeon R89 board: - Required root node properties: - - compatible = "netxeon,r89", "rockchip,rk3288"; - -- GeekBuying GeekBox: - Required root node properties: - - compatible = "geekbuying,geekbox", "rockchip,rk3368"; - -- Google Bob (Asus Chromebook Flip C101PA): - Required root node properties: - compatible = "google,bob-rev13", "google,bob-rev12", - "google,bob-rev11", "google,bob-rev10", - "google,bob-rev9", "google,bob-rev8", - "google,bob-rev7", "google,bob-rev6", - "google,bob-rev5", "google,bob-rev4", - "google,bob", "google,gru", "rockchip,rk3399"; - -- Google Brain (dev-board): - Required root node properties: - - compatible = "google,veyron-brain-rev0", "google,veyron-brain", - "google,veyron", "rockchip,rk3288"; - -- Google Gru (dev-board): - Required root node properties: - - compatible = "google,gru-rev15", "google,gru-rev14", - "google,gru-rev13", "google,gru-rev12", - "google,gru-rev11", "google,gru-rev10", - "google,gru-rev9", "google,gru-rev8", - "google,gru-rev7", "google,gru-rev6", - "google,gru-rev5", "google,gru-rev4", - "google,gru-rev3", "google,gru-rev2", - "google,gru", "rockchip,rk3399"; - -- Google Jaq (Haier Chromebook 11 and more): - Required root node properties: - - compatible = "google,veyron-jaq-rev5", "google,veyron-jaq-rev4", - "google,veyron-jaq-rev3", "google,veyron-jaq-rev2", - "google,veyron-jaq-rev1", "google,veyron-jaq", - "google,veyron", "rockchip,rk3288"; - -- Google Jerry (Hisense Chromebook C11 and more): - Required root node properties: - - compatible = "google,veyron-jerry-rev7", "google,veyron-jerry-rev6", - "google,veyron-jerry-rev5", "google,veyron-jerry-rev4", - "google,veyron-jerry-rev3", "google,veyron-jerry", - "google,veyron", "rockchip,rk3288"; - -- Google Kevin (Samsung Chromebook Plus): - Required root node properties: - - compatible = "google,kevin-rev15", "google,kevin-rev14", - "google,kevin-rev13", "google,kevin-rev12", - "google,kevin-rev11", "google,kevin-rev10", - "google,kevin-rev9", "google,kevin-rev8", - "google,kevin-rev7", "google,kevin-rev6", - "google,kevin", "google,gru", "rockchip,rk3399"; - -- Google Mickey (Asus Chromebit CS10): - Required root node properties: - - compatible = "google,veyron-mickey-rev8", "google,veyron-mickey-rev7", - "google,veyron-mickey-rev6", "google,veyron-mickey-rev5", - "google,veyron-mickey-rev4", "google,veyron-mickey-rev3", - "google,veyron-mickey-rev2", "google,veyron-mickey-rev1", - "google,veyron-mickey-rev0", "google,veyron-mickey", - "google,veyron", "rockchip,rk3288"; - -- Google Minnie (Asus Chromebook Flip C100P): - Required root node properties: - - compatible = "google,veyron-minnie-rev4", "google,veyron-minnie-rev3", - "google,veyron-minnie-rev2", "google,veyron-minnie-rev1", - "google,veyron-minnie-rev0", "google,veyron-minnie", - "google,veyron", "rockchip,rk3288"; - -- Google Pinky (dev-board): - Required root node properties: - - compatible = "google,veyron-pinky-rev2", "google,veyron-pinky", - "google,veyron", "rockchip,rk3288"; - -- Google Speedy (Asus C201 Chromebook): - Required root node properties: - - compatible = "google,veyron-speedy-rev9", "google,veyron-speedy-rev8", - "google,veyron-speedy-rev7", "google,veyron-speedy-rev6", - "google,veyron-speedy-rev5", "google,veyron-speedy-rev4", - "google,veyron-speedy-rev3", "google,veyron-speedy-rev2", - "google,veyron-speedy", "google,veyron", "rockchip,rk3288"; - -- mqmaker MiQi: - Required root node properties: - - compatible = "mqmaker,miqi", "rockchip,rk3288"; - -- Phytec phyCORE-RK3288: Rapid Development Kit - Required root node properties: - - compatible = "phytec,rk3288-pcm-947", "phytec,rk3288-phycore-som", "rockchip,rk3288"; - -- Pine64 Rock64 board: - Required root node properties: - - compatible = "pine64,rock64", "rockchip,rk3328"; - -- Pine64 RockPro64 board: - Required root node properties: - - compatible = "pine64,rockpro64", "rockchip,rk3399"; - -- Rockchip PX3 Evaluation board: - Required root node properties: - - compatible = "rockchip,px3-evb", "rockchip,px3", "rockchip,rk3188"; - -- Rockchip PX5 Evaluation board: - Required root node properties: - - compatible = "rockchip,px5-evb", "rockchip,px5", "rockchip,rk3368"; - -- Rockchip PX30 Evaluation board: - Required root node properties: - - compatible = "rockchip,px30-evb", "rockchip,px30"; - -- Rockchip RV1108 Evaluation board - Required root node properties: - - compatible = "rockchip,rv1108-evb", "rockchip,rv1108"; - -- Rockchip RK3368 evb: - Required root node properties: - - compatible = "rockchip,rk3368-evb-act8846", "rockchip,rk3368"; - -- Rockchip R88 board: - Required root node properties: - - compatible = "rockchip,r88", "rockchip,rk3368"; - -- Rockchip RK3228 Evaluation board: - Required root node properties: - - compatible = "rockchip,rk3228-evb", "rockchip,rk3228"; - -- Rockchip RK3229 Evaluation board: - - compatible = "rockchip,rk3229-evb", "rockchip,rk3229"; - -- Rockchip RK3288 Fennec board: - Required root node properties: - - compatible = "rockchip,rk3288-fennec", "rockchip,rk3288"; - -- Rockchip RK3328 evb: - Required root node properties: - - compatible = "rockchip,rk3328-evb", "rockchip,rk3328"; - -- Rockchip RK3399 evb: - Required root node properties: - - compatible = "rockchip,rk3399-evb", "rockchip,rk3399"; - -- Rockchip RK3399 Sapphire board standalone: - Required root node properties: - - compatible = "rockchip,rk3399-sapphire", "rockchip,rk3399"; - -- Rockchip RK3399 Sapphire Excavator board: - Required root node properties: - - compatible = "rockchip,rk3399-sapphire-excavator", "rockchip,rk3399"; - -- Theobroma Systems RK3368-uQ7 Haikou Baseboard: - Required root node properties: - - compatible = "tsd,rk3368-uq7-haikou", "rockchip,rk3368"; - -- Theobroma Systems RK3399-Q7 Haikou Baseboard: - Required root node properties: - - compatible = "tsd,rk3399-q7-haikou", "rockchip,rk3399"; - -- Tronsmart Orion R68 Meta - Required root node properties: - - compatible = "tronsmart,orion-r68-meta", "rockchip,rk3368"; diff --git a/Documentation/devicetree/bindings/arm/rockchip.yaml b/Documentation/devicetree/bindings/arm/rockchip.yaml new file mode 100644 index 000000000000..b12958bda09c --- /dev/null +++ b/Documentation/devicetree/bindings/arm/rockchip.yaml @@ -0,0 +1,423 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/rockchip.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Rockchip platforms device tree bindings + +maintainers: + - Heiko Stuebner <heiko@sntech.de> + +properties: + $nodename: + const: '/' + compatible: + oneOf: + + - description: 96boards RK3399 Ficus (ROCK960 Enterprise Edition) + items: + - const: vamrs,ficus + - const: rockchip,rk3399 + + - description: 96boards RK3399 Rock960 (ROCK960 Consumer Edition) + items: + - const: vamrs,rock960 + - const: rockchip,rk3399 + + - description: Amarula Vyasa RK3288 + items: + - const: amarula,vyasa-rk3288 + - const: rockchip,rk3288 + + - description: Asus Tinker board + items: + - const: asus,rk3288-tinker + - const: rockchip,rk3288 + + - description: Asus Tinker board S + items: + - const: asus,rk3288-tinker-s + - const: rockchip,rk3288 + + - description: bq Curie 2 tablet + items: + - const: mundoreader,bq-curie2 + - const: rockchip,rk3066a + + - description: bq Edison 2 Quad-Core tablet + items: + - const: mundoreader,bq-edison2qc + - const: rockchip,rk3188 + + - description: ChipSPARK PopMetal-RK3288 + items: + - const: chipspark,popmetal-rk3288 + - const: rockchip,rk3288 + + - description: ChipSPARK Rayeager PX2 + items: + - const: chipspark,rayeager-px2 + - const: rockchip,rk3066a + + - description: Firefly Firefly-RK3288 + items: + - enum: + - firefly,firefly-rk3288 + - firefly,firefly-rk3288-beta + - const: rockchip,rk3288 + + - description: Firefly Firefly-RK3288 Reload + items: + - const: firefly,firefly-rk3288-reload + - const: rockchip,rk3288 + + - description: Firefly Firefly-RK3399 + items: + - const: firefly,firefly-rk3399 + - const: rockchip,rk3399 + + - description: Firefly roc-rk3328-cc + items: + - const: firefly,roc-rk3328-cc + - const: rockchip,rk3328 + + - description: Firefly ROC-RK3399-PC + items: + - const: firefly,roc-rk3399-pc + - const: rockchip,rk3399 + + - description: GeekBuying GeekBox + items: + - const: geekbuying,geekbox + - const: rockchip,rk3368 + + - description: Google Bob (Asus Chromebook Flip C101PA) + items: + - const: google,bob-rev13 + - const: google,bob-rev12 + - const: google,bob-rev11 + - const: google,bob-rev10 + - const: google,bob-rev9 + - const: google,bob-rev8 + - const: google,bob-rev7 + - const: google,bob-rev6 + - const: google,bob-rev5 + - const: google,bob-rev4 + - const: google,bob + - const: google,gru + - const: rockchip,rk3399 + + - description: Google Brain (dev-board) + items: + - const: google,veyron-brain-rev0 + - const: google,veyron-brain + - const: google,veyron + - const: rockchip,rk3288 + + - description: Google Gru (dev-board) + items: + - const: google,gru-rev15 + - const: google,gru-rev14 + - const: google,gru-rev13 + - const: google,gru-rev12 + - const: google,gru-rev11 + - const: google,gru-rev10 + - const: google,gru-rev9 + - const: google,gru-rev8 + - const: google,gru-rev7 + - const: google,gru-rev6 + - const: google,gru-rev5 + - const: google,gru-rev4 + - const: google,gru-rev3 + - const: google,gru-rev2 + - const: google,gru + - const: rockchip,rk3399 + + - description: Google Jaq (Haier Chromebook 11 and more) + items: + - const: google,veyron-jaq-rev5 + - const: google,veyron-jaq-rev4 + - const: google,veyron-jaq-rev3 + - const: google,veyron-jaq-rev2 + - const: google,veyron-jaq-rev1 + - const: google,veyron-jaq + - const: google,veyron + - const: rockchip,rk3288 + + - description: Google Jerry (Hisense Chromebook C11 and more) + items: + - const: google,veyron-jerry-rev7 + - const: google,veyron-jerry-rev6 + - const: google,veyron-jerry-rev5 + - const: google,veyron-jerry-rev4 + - const: google,veyron-jerry-rev3 + - const: google,veyron-jerry + - const: google,veyron + - const: rockchip,rk3288 + + - description: Google Kevin (Samsung Chromebook Plus) + items: + - const: google,kevin-rev15 + - const: google,kevin-rev14 + - const: google,kevin-rev13 + - const: google,kevin-rev12 + - const: google,kevin-rev11 + - const: google,kevin-rev10 + - const: google,kevin-rev9 + - const: google,kevin-rev8 + - const: google,kevin-rev7 + - const: google,kevin-rev6 + - const: google,kevin + - const: google,gru + - const: rockchip,rk3399 + + - description: Google Mickey (Asus Chromebit CS10) + items: + - const: google,veyron-mickey-rev8 + - const: google,veyron-mickey-rev7 + - const: google,veyron-mickey-rev6 + - const: google,veyron-mickey-rev5 + - const: google,veyron-mickey-rev4 + - const: google,veyron-mickey-rev3 + - const: google,veyron-mickey-rev2 + - const: google,veyron-mickey-rev1 + - const: google,veyron-mickey-rev0 + - const: google,veyron-mickey + - const: google,veyron + - const: rockchip,rk3288 + + - description: Google Minnie (Asus Chromebook Flip C100P) + items: + - const: google,veyron-minnie-rev4 + - const: google,veyron-minnie-rev3 + - const: google,veyron-minnie-rev2 + - const: google,veyron-minnie-rev1 + - const: google,veyron-minnie-rev0 + - const: google,veyron-minnie + - const: google,veyron + - const: rockchip,rk3288 + + - description: Google Pinky (dev-board) + items: + - const: google,veyron-pinky-rev2 + - const: google,veyron-pinky + - const: google,veyron + - const: rockchip,rk3288 + + - description: Google Scarlet - Kingdisplay (Acer Chromebook Tab 10) + items: + - const: google,scarlet-rev15-sku7 + - const: google,scarlet-rev15 + - const: google,scarlet-rev14-sku7 + - const: google,scarlet-rev14 + - const: google,scarlet-rev13-sku7 + - const: google,scarlet-rev13 + - const: google,scarlet-rev12-sku7 + - const: google,scarlet-rev12 + - const: google,scarlet-rev11-sku7 + - const: google,scarlet-rev11 + - const: google,scarlet-rev10-sku7 + - const: google,scarlet-rev10 + - const: google,scarlet-rev9-sku7 + - const: google,scarlet-rev9 + - const: google,scarlet-rev8-sku7 + - const: google,scarlet-rev8 + - const: google,scarlet-rev7-sku7 + - const: google,scarlet-rev7 + - const: google,scarlet-rev6-sku7 + - const: google,scarlet-rev6 + - const: google,scarlet-rev5-sku7 + - const: google,scarlet-rev5 + - const: google,scarlet-rev4-sku7 + - const: google,scarlet-rev4 + - const: google,scarlet-rev3-sku7 + - const: google,scarlet-rev3 + - const: google,scarlet + - const: google,gru + - const: rockchip,rk3399 + + - description: Google Scarlet - Innolux display (Acer Chromebook Tab 10) + items: + - const: google,scarlet-rev15-sku6 + - const: google,scarlet-rev15 + - const: google,scarlet-rev14-sku6 + - const: google,scarlet-rev14 + - const: google,scarlet-rev13-sku6 + - const: google,scarlet-rev13 + - const: google,scarlet-rev12-sku6 + - const: google,scarlet-rev12 + - const: google,scarlet-rev11-sku6 + - const: google,scarlet-rev11 + - const: google,scarlet-rev10-sku6 + - const: google,scarlet-rev10 + - const: google,scarlet-rev9-sku6 + - const: google,scarlet-rev9 + - const: google,scarlet-rev8-sku6 + - const: google,scarlet-rev8 + - const: google,scarlet-rev7-sku6 + - const: google,scarlet-rev7 + - const: google,scarlet-rev6-sku6 + - const: google,scarlet-rev6 + - const: google,scarlet-rev5-sku6 + - const: google,scarlet-rev5 + - const: google,scarlet-rev4-sku6 + - const: google,scarlet-rev4 + - const: google,scarlet + - const: google,gru + - const: rockchip,rk3399 + + - description: Google Speedy (Asus C201 Chromebook) + items: + - const: google,veyron-speedy-rev9 + - const: google,veyron-speedy-rev8 + - const: google,veyron-speedy-rev7 + - const: google,veyron-speedy-rev6 + - const: google,veyron-speedy-rev5 + - const: google,veyron-speedy-rev4 + - const: google,veyron-speedy-rev3 + - const: google,veyron-speedy-rev2 + - const: google,veyron-speedy + - const: google,veyron + - const: rockchip,rk3288 + + - description: Haoyu MarsBoard RK3066 + items: + - const: haoyu,marsboard-rk3066 + - const: rockchip,rk3066a + + - description: mqmaker MiQi + items: + - const: mqmaker,miqi + - const: rockchip,rk3288 + + - description: Netxeon R89 board + items: + - const: netxeon,r89 + - const: rockchip,rk3288 + + - description: Phytec phyCORE-RK3288 Rapid Development Kit + items: + - const: phytec,rk3288-pcm-947 + - const: phytec,rk3288-phycore-som + - const: rockchip,rk3288 + + - description: Pine64 Rock64 + items: + - const: pine64,rock64 + - const: rockchip,rk3328 + + - description: Pine64 RockPro64 + items: + - const: pine64,rockpro64 + - const: rockchip,rk3399 + + - description: Radxa Rock + items: + - const: radxa,rock + - const: rockchip,rk3188 + + - description: Radxa Rock2 Square + items: + - const: radxa,rock2-square + - const: rockchip,rk3288 + + - description: Rikomagic MK808 v1 + items: + - const: rikomagic,mk808 + - const: rockchip,rk3066a + + - description: Rockchip Kylin + items: + - const: rockchip,kylin-rk3036 + - const: rockchip,rk3036 + + - description: Rockchip PX3 Evaluation board + items: + - const: rockchip,px3-evb + - const: rockchip,px3 + - const: rockchip,rk3188 + + - description: Rockchip PX30 Evaluation board + items: + - const: rockchip,px30-evb + - const: rockchip,px30 + + - description: Rockchip PX5 Evaluation board + items: + - const: rockchip,px5-evb + - const: rockchip,px5 + - const: rockchip,rk3368 + + - description: Rockchip R88 + items: + - const: rockchip,r88 + - const: rockchip,rk3368 + + - description: Rockchip RK3228 Evaluation board + items: + - const: rockchip,rk3228-evb + - const: rockchip,rk3228 + + - description: Rockchip RK3229 Evaluation board + items: + - const: rockchip,rk3229-evb + - const: rockchip,rk3229 + + - description: Rockchip RK3288 Evaluation board + items: + - enum: + - rockchip,rk3288-evb-act8846 + - rockchip,rk3288-evb-rk808 + - const: rockchip,rk3288 + + - description: Rockchip RK3288 Fennec + items: + - const: rockchip,rk3288-fennec + - const: rockchip,rk3288 + + - description: Rockchip RK3328 Evaluation board + items: + - const: rockchip,rk3328-evb + - const: rockchip,rk3328 + + - description: Rockchip RK3368 Evaluation board (act8846 pmic) + items: + - const: rockchip,rk3368-evb-act8846 + - const: rockchip,rk3368 + + - description: Rockchip RK3399 Evaluation board + items: + - const: rockchip,rk3399-evb + - const: rockchip,rk3399 + + - description: Rockchip RK3399 Sapphire standalone + items: + - const: rockchip,rk3399-sapphire + - const: rockchip,rk3399 + + - description: Rockchip RK3399 Sapphire with Excavator Baseboard + items: + - const: rockchip,rk3399-sapphire-excavator + - const: rockchip,rk3399 + + - description: Rockchip RV1108 Evaluation board + items: + - const: rockchip,rv1108-evb + - const: rockchip,rv1108 + + - description: Theobroma Systems RK3368-uQ7 with Haikou baseboard + items: + - const: tsd,rk3368-uq7-haikou + - const: rockchip,rk3368 + + - description: Theobroma Systems RK3399-Q7 with Haikou baseboard + items: + - const: tsd,rk3399-q7-haikou + - const: rockchip,rk3399 + + - description: Tronsmart Orion R68 Meta + items: + - const: tronsmart,orion-r68-meta + - const: rockchip,rk3368 +... diff --git a/Documentation/devicetree/bindings/arm/shmobile.txt b/Documentation/devicetree/bindings/arm/shmobile.txt index 58c4256d37a3..7f91c2a8b54e 100644 --- a/Documentation/devicetree/bindings/arm/shmobile.txt +++ b/Documentation/devicetree/bindings/arm/shmobile.txt @@ -101,6 +101,10 @@ Boards: compatible = "iwave,g20d", "iwave,g20m", "renesas,r8a7743" - iWave Systems RZ/G1M Qseven System On Module (iW-RainboW-G20M-Qseven) compatible = "iwave,g20m", "renesas,r8a7743" + - iWave Systems RZ/G1N Qseven Development Platform (iW-RainboW-G20D-Qseven) + compatible = "iwave,g20d", "iwave,g20m", "renesas,r8a7744" + - iWave Systems RZ/G1N Qseven System On Module (iW-RainboW-G20M-Qseven) + compatible = "iwave,g20m", "renesas,r8a7744" - Kingfisher (SBEV-RCAR-KF-M03) compatible = "shimafuji,kingfisher" - Koelsch (RTP0RC7791SEB00010S) @@ -149,21 +153,3 @@ Boards: compatible = "renesas,v3msk", "renesas,r8a77970" - Wheat (RTP0RC7792ASKB0000JE) compatible = "renesas,wheat", "renesas,r8a7792" - - -Most Renesas ARM SoCs have a Product Register or Boundary Scan ID Register that -allows to retrieve SoC product and revision information. If present, a device -node for this register should be added. - -Required properties: - - compatible: Must be "renesas,prr" or "renesas,bsid" - - reg: Base address and length of the register block. - - -Examples --------- - - prr: chipid@ff000044 { - compatible = "renesas,prr"; - reg = <0 0xff000044 0 4>; - }; diff --git a/Documentation/devicetree/bindings/arm/sirf.txt b/Documentation/devicetree/bindings/arm/sirf.txt deleted file mode 100644 index 7b28ee6fee91..000000000000 --- a/Documentation/devicetree/bindings/arm/sirf.txt +++ /dev/null @@ -1,11 +0,0 @@ -CSR SiRFprimaII and SiRFmarco device tree bindings. -======================================== - -Required root node properties: - - compatible: - - "sirf,atlas6-cb" : atlas6 "cb" evaluation board - - "sirf,atlas6" : atlas6 device based board - - "sirf,atlas7-cb" : atlas7 "cb" evaluation board - - "sirf,atlas7" : atlas7 device based board - - "sirf,prima2-cb" : prima2 "cb" evaluation board - - "sirf,prima2" : prima2 device based board diff --git a/Documentation/devicetree/bindings/arm/sirf.yaml b/Documentation/devicetree/bindings/arm/sirf.yaml new file mode 100644 index 000000000000..0b597032c923 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/sirf.yaml @@ -0,0 +1,27 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/sirf.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: CSR SiRFprimaII and SiRFmarco device tree bindings. + +maintainers: + - Binghua Duan <binghua.duan@csr.com> + - Barry Song <Baohua.Song@csr.com> + +properties: + $nodename: + const: '/' + compatible: + oneOf: + - items: + - const: sirf,atlas6-cb + - const: sirf,atlas6 + - items: + - const: sirf,atlas7-cb + - const: sirf,atlas7 + - items: + - const: sirf,prima2-cb + - const: sirf,prima2 +... diff --git a/Documentation/devicetree/bindings/arm/uniphier/cache-uniphier.txt b/Documentation/devicetree/bindings/arm/socionext/cache-uniphier.txt index d27a646f48a9..d27a646f48a9 100644 --- a/Documentation/devicetree/bindings/arm/uniphier/cache-uniphier.txt +++ b/Documentation/devicetree/bindings/arm/socionext/cache-uniphier.txt diff --git a/Documentation/devicetree/bindings/arm/socionext/uniphier.txt b/Documentation/devicetree/bindings/arm/socionext/uniphier.txt new file mode 100644 index 000000000000..b3ed1033740e --- /dev/null +++ b/Documentation/devicetree/bindings/arm/socionext/uniphier.txt @@ -0,0 +1,47 @@ +Socionext UniPhier SoC family +----------------------------- + +Required properties in the root node: + - compatible: should contain board and SoC compatible strings + +SoC and board compatible strings: + (sorted chronologically) + + - LD4 SoC: "socionext,uniphier-ld4" + - Reference Board: "socionext,uniphier-ld4-ref" + + - Pro4 SoC: "socionext,uniphier-pro4" + - Reference Board: "socionext,uniphier-pro4-ref" + - Ace Board: "socionext,uniphier-pro4-ace" + - Sanji Board: "socionext,uniphier-pro4-sanji" + + - sLD8 SoC: "socionext,uniphier-sld8" + - Reference Board: "socionext,uniphier-sld8-ref" + + - PXs2 SoC: "socionext,uniphier-pxs2" + - Gentil Board: "socionext,uniphier-pxs2-gentil" + - Vodka Board: "socionext,uniphier-pxs2-vodka" + + - LD6b SoC: "socionext,uniphier-ld6b" + - Reference Board: "socionext,uniphier-ld6b-ref" + + - LD11 SoC: "socionext,uniphier-ld11" + - Reference Board: "socionext,uniphier-ld11-ref" + - Global Board: "socionext,uniphier-ld11-global" + + - LD20 SoC: "socionext,uniphier-ld20" + - Reference Board: "socionext,uniphier-ld20-ref" + - Global Board: "socionext,uniphier-ld20-global" + + - PXs3 SoC: "socionext,uniphier-pxs3" + - Reference Board: "socionext,uniphier-pxs3-ref" + +Example: + +/dts-v1/; + +/ { + compatible = "socionext,uniphier-ld20-ref", "socionext,uniphier-ld20"; + + ... +}; diff --git a/Documentation/devicetree/bindings/arm/spear.txt b/Documentation/devicetree/bindings/arm/spear.txt deleted file mode 100644 index 0d42949df6c2..000000000000 --- a/Documentation/devicetree/bindings/arm/spear.txt +++ /dev/null @@ -1,26 +0,0 @@ -ST SPEAr Platforms Device Tree Bindings ---------------------------------------- - -Boards with the ST SPEAr600 SoC shall have the following properties: -Required root node property: -compatible = "st,spear600"; - -Boards with the ST SPEAr300 SoC shall have the following properties: -Required root node property: -compatible = "st,spear300"; - -Boards with the ST SPEAr310 SoC shall have the following properties: -Required root node property: -compatible = "st,spear310"; - -Boards with the ST SPEAr320 SoC shall have the following properties: -Required root node property: -compatible = "st,spear320"; - -Boards with the ST SPEAr1310 SoC shall have the following properties: -Required root node property: -compatible = "st,spear1310"; - -Boards with the ST SPEAr1340 SoC shall have the following properties: -Required root node property: -compatible = "st,spear1340"; diff --git a/Documentation/devicetree/bindings/arm/spear.yaml b/Documentation/devicetree/bindings/arm/spear.yaml new file mode 100644 index 000000000000..f6ec731c9531 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/spear.yaml @@ -0,0 +1,25 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/spear.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: ST SPEAr Platforms Device Tree Bindings + +maintainers: + - Viresh Kumar <vireshk@kernel.org> + - Stefan Roese <sr@denx.de> + +properties: + $nodename: + const: '/' + compatible: + items: + - enum: + - st,spear600 + - st,spear300 + - st,spear310 + - st,spear320 + - st,spear1310 + - st,spear1340 +... diff --git a/Documentation/devicetree/bindings/arm/sti.txt b/Documentation/devicetree/bindings/arm/sti.txt deleted file mode 100644 index 8d27f6b084c7..000000000000 --- a/Documentation/devicetree/bindings/arm/sti.txt +++ /dev/null @@ -1,23 +0,0 @@ -ST STi Platforms Device Tree Bindings ---------------------------------------- - -Boards with the ST STiH415 SoC shall have the following properties: -Required root node property: -compatible = "st,stih415"; - -Boards with the ST STiH416 SoC shall have the following properties: -Required root node property: -compatible = "st,stih416"; - -Boards with the ST STiH407 SoC shall have the following properties: -Required root node property: -compatible = "st,stih407"; - -Boards with the ST STiH410 SoC shall have the following properties: -Required root node property: -compatible = "st,stih410"; - -Boards with the ST STiH418 SoC shall have the following properties: -Required root node property: -compatible = "st,stih418"; - diff --git a/Documentation/devicetree/bindings/arm/sti.yaml b/Documentation/devicetree/bindings/arm/sti.yaml new file mode 100644 index 000000000000..47f9b8eebaa0 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/sti.yaml @@ -0,0 +1,23 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/sti.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: ST STi Platforms Device Tree Bindings + +maintainers: + - Patrice Chotard <patrice.chotard@st.com> + +properties: + $nodename: + const: '/' + compatible: + items: + - enum: + - st,stih415 + - st,stih416 + - st,stih407 + - st,stih410 + - st,stih418 +... diff --git a/Documentation/devicetree/bindings/arm/sunxi.txt b/Documentation/devicetree/bindings/arm/sunxi.txt index e4beec3d9ad3..9254cbe7d516 100644 --- a/Documentation/devicetree/bindings/arm/sunxi.txt +++ b/Documentation/devicetree/bindings/arm/sunxi.txt @@ -14,8 +14,10 @@ using one of the following compatible strings: allwinner,sun8i-a83t allwinner,sun8i-h2-plus allwinner,sun8i-h3 - allwinner-sun8i-r40 + allwinner,sun8i-r40 + allwinner,sun8i-t3 allwinner,sun8i-v3s allwinner,sun9i-a80 allwinner,sun50i-a64 + allwinner,suniv-f1c100s nextthing,gr8 diff --git a/Documentation/devicetree/bindings/arm/tegra.txt b/Documentation/devicetree/bindings/arm/tegra.txt deleted file mode 100644 index c59b15f64346..000000000000 --- a/Documentation/devicetree/bindings/arm/tegra.txt +++ /dev/null @@ -1,65 +0,0 @@ -NVIDIA Tegra device tree bindings -------------------------------------------- - -SoCs -------------------------------------------- - -Each device tree must specify which Tegra SoC it uses, using one of the -following compatible values: - - nvidia,tegra20 - nvidia,tegra30 - nvidia,tegra114 - nvidia,tegra124 - nvidia,tegra132 - nvidia,tegra210 - nvidia,tegra186 - nvidia,tegra194 - -Boards -------------------------------------------- - -Each device tree must specify which one or more of the following -board-specific compatible values: - - ad,medcom-wide - ad,plutux - ad,tamonten - ad,tec - compal,paz00 - compulab,trimslice - nvidia,beaver - nvidia,cardhu - nvidia,cardhu-a02 - nvidia,cardhu-a04 - nvidia,dalmore - nvidia,harmony - nvidia,jetson-tk1 - nvidia,norrin - nvidia,p2371-0000 - nvidia,p2371-2180 - nvidia,p2571 - nvidia,p2771-0000 - nvidia,p2972-0000 - nvidia,roth - nvidia,seaboard - nvidia,tn7 - nvidia,ventana - toradex,apalis_t30 - toradex,apalis_t30-eval - toradex,apalis_t30-v1.1 - toradex,apalis_t30-v1.1-eval - toradex,apalis-tk1 - toradex,apalis-tk1-eval - toradex,apalis-tk1-v1.2 - toradex,apalis-tk1-v1.2-eval - toradex,colibri_t20 - toradex,colibri_t20-eval-v3 - toradex,colibri_t20-iris - toradex,colibri_t30 - toradex,colibri_t30-eval-v3 - -Trusted Foundations -------------------------------------------- -Tegra supports the Trusted Foundation secure monitor. See the -"tlm,trusted-foundations" binding's documentation for more details. diff --git a/Documentation/devicetree/bindings/arm/tegra.yaml b/Documentation/devicetree/bindings/arm/tegra.yaml new file mode 100644 index 000000000000..fbcde8a7e067 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/tegra.yaml @@ -0,0 +1,101 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/tegra.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: NVIDIA Tegra device tree bindings + +maintainers: + - Thierry Reding <thierry.reding@gmail.com> + - Jonathan Hunter <jonathanh@nvidia.com> + +properties: + compatible: + oneOf: + - items: + - enum: + - compal,paz00 + - compulab,trimslice + - nvidia,harmony + - nvidia,seaboard + - nvidia,ventana + - const: nvidia,tegra20 + - items: + - enum: + - ad,medcom-wide + - ad,plutux + - ad,tec + - const: ad,tamonten + - const: nvidia,tegra20 + - items: + - enum: + - toradex,colibri_t20-eval-v3 + - toradex,colibri_t20-iris + - const: toradex,colibri_t20 + - const: nvidia,tegra20 + - items: + - enum: + - nvidia,beaver + - const: nvidia,tegra30 + - items: + - enum: + - nvidia,cardhu-a02 + - nvidia,cardhu-a04 + - const: nvidia,cardhu + - const: nvidia,tegra30 + - items: + - const: toradex,apalis_t30-eval + - const: toradex,apalis_t30 + - const: nvidia,tegra30 + - items: + - const: toradex,apalis_t30-eval-v1.1 + - const: toradex,apalis_t30-eval + - const: toradex,apalis_t30-v1.1 + - const: toradex,apalis_t30 + - const: nvidia,tegra30 + - items: + - enum: + - toradex,colibri_t30-eval-v3 + - const: toradex,colibri_t30 + - const: nvidia,tegra30 + - items: + - enum: + - nvidia,dalmore + - nvidia,roth + - nvidia,tn7 + - const: nvidia,tegra114 + - items: + - enum: + - nvidia,jetson-tk1 + - nvidia,venice2 + - const: nvidia,tegra124 + - items: + - const: toradex,apalis-tk1-eval + - const: toradex,apalis-tk1 + - const: nvidia,tegra124 + - items: + - const: toradex,apalis-tk1-v1.2-eval + - const: toradex,apalis-tk1-eval + - const: toradex,apalis-tk1-v1.2 + - const: toradex,apalis-tk1 + - const: nvidia,tegra124 + - items: + - enum: + - nvidia,norrin + - const: nvidia,tegra132 + - const: nvidia,tegra124 + - items: + - enum: + - nvidia,p2371-0000 + - nvidia,p2371-2180 + - nvidia,p2571 + - const: nvidia,tegra210 + - items: + - enum: + - nvidia,p2771-0000 + - const: nvidia,tegra186 + - items: + - enum: + - nvidia,p2972-0000 + - const: nvidia,tegra194 diff --git a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra186-pmc.txt b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra186-pmc.txt index c9fd6d1de57e..2d89cdc39eb0 100644 --- a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra186-pmc.txt +++ b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra186-pmc.txt @@ -15,6 +15,9 @@ Required properties: Optional properties: - nvidia,invert-interrupt: If present, inverts the PMU interrupt signal. +- interrupt-controller: Identifies the node as an interrupt controller. +- #interrupt-cells: Specifies the number of cells needed to encode an + interrupt source. The value must be 2. Example: diff --git a/Documentation/devicetree/bindings/arm/ti/nspire.yaml b/Documentation/devicetree/bindings/arm/ti/nspire.yaml new file mode 100644 index 000000000000..e372b43da62f --- /dev/null +++ b/Documentation/devicetree/bindings/arm/ti/nspire.yaml @@ -0,0 +1,24 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/ti/nspire.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: TI-NSPIRE calculators + +maintainers: + - Daniel Tang <dt.tangr@gmail.com> + +properties: + $nodename: + const: '/' + compatible: + items: + - enum: + # CX models + - ti,nspire-cx + # Touchpad models + - ti,nspire-tp + # Clickpad models + - ti,nspire-clp +... diff --git a/Documentation/devicetree/bindings/arm/ti/ti,davinci.yaml b/Documentation/devicetree/bindings/arm/ti/ti,davinci.yaml new file mode 100644 index 000000000000..4326d2cfa15d --- /dev/null +++ b/Documentation/devicetree/bindings/arm/ti/ti,davinci.yaml @@ -0,0 +1,26 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/ti/davinci.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Texas Instruments DaVinci Platforms Device Tree Bindings + +maintainers: + - Sekhar Nori <nsekhar@ti.com> + +description: + DA850/OMAP-L138/AM18x based boards + +properties: + $nodename: + const: '/' + compatible: + items: + - enum: + - ti,da850-evm # DA850/OMAP-L138/AM18x Evaluation Module (EVM) board + - ti,da850-lcdk # DA850/OMAP-L138/AM18x L138/C6748 Development Kit (LCDK) board + - enbw,cmc # EnBW AM1808 based CMC board + - lego,ev3 # LEGO MINDSTORMS EV3 (AM1808 based) + - const: ti,da850 +... diff --git a/Documentation/devicetree/bindings/arm/vt8500.txt b/Documentation/devicetree/bindings/arm/vt8500.txt deleted file mode 100644 index 87dc1ddf4770..000000000000 --- a/Documentation/devicetree/bindings/arm/vt8500.txt +++ /dev/null @@ -1,22 +0,0 @@ -VIA/Wondermedia VT8500 Platforms Device Tree Bindings ---------------------------------------- - -Boards with the VIA VT8500 SoC shall have the following properties: -Required root node property: -compatible = "via,vt8500"; - -Boards with the Wondermedia WM8505 SoC shall have the following properties: -Required root node property: -compatible = "wm,wm8505"; - -Boards with the Wondermedia WM8650 SoC shall have the following properties: -Required root node property: -compatible = "wm,wm8650"; - -Boards with the Wondermedia WM8750 SoC shall have the following properties: -Required root node property: -compatible = "wm,wm8750"; - -Boards with the Wondermedia WM8850 SoC shall have the following properties: -Required root node property: -compatible = "wm,wm8850"; diff --git a/Documentation/devicetree/bindings/arm/vt8500.yaml b/Documentation/devicetree/bindings/arm/vt8500.yaml new file mode 100644 index 000000000000..7b25b6fa34e9 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/vt8500.yaml @@ -0,0 +1,23 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/vt8500.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: VIA/Wondermedia VT8500 Platforms Device Tree Bindings + +maintainers: + - Tony Prisk <linux@prisktech.co.nz> +description: test + +properties: + $nodename: + const: '/' + compatible: + items: + - enum: + - via,vt8500 + - wm,wm8505 + - wm,wm8650 + - wm,wm8750 + - wm,wm8850 diff --git a/Documentation/devicetree/bindings/arm/xilinx.txt b/Documentation/devicetree/bindings/arm/xilinx.txt deleted file mode 100644 index 26fe5ecc4332..000000000000 --- a/Documentation/devicetree/bindings/arm/xilinx.txt +++ /dev/null @@ -1,83 +0,0 @@ -Xilinx Zynq Platforms Device Tree Bindings - -Boards with Zynq-7000 SOC based on an ARM Cortex A9 processor -shall have the following properties. - -Required root node properties: - - compatible = "xlnx,zynq-7000"; - -Additional compatible strings: - -- Adapteva Parallella board - "adapteva,parallella" - -- Avnet MicroZed board - "avnet,zynq-microzed" - "xlnx,zynq-microzed" - -- Avnet ZedBoard board - "avnet,zynq-zed" - "xlnx,zynq-zed" - -- Digilent Zybo board - "digilent,zynq-zybo" - -- Digilent Zybo Z7 board - "digilent,zynq-zybo-z7" - -- Xilinx CC108 internal board - "xlnx,zynq-cc108" - -- Xilinx ZC702 internal board - "xlnx,zynq-zc702" - -- Xilinx ZC706 internal board - "xlnx,zynq-zc706" - -- Xilinx ZC770 internal board, with different FMC cards - "xlnx,zynq-zc770-xm010" - "xlnx,zynq-zc770-xm011" - "xlnx,zynq-zc770-xm012" - "xlnx,zynq-zc770-xm013" - ---------------------------------------------------------------- - -Xilinx Zynq UltraScale+ MPSoC Platforms Device Tree Bindings - -Boards with ZynqMP SOC based on an ARM Cortex A53 processor -shall have the following properties. - -Required root node properties: - - compatible = "xlnx,zynqmp"; - - -Additional compatible strings: - -- Xilinx internal board zc1232 - "xlnx,zynqmp-zc1232-revA", "xlnx,zynqmp-zc1232" - -- Xilinx internal board zc1254 - "xlnx,zynqmp-zc1254-revA", "xlnx,zynqmp-zc1254" - -- Xilinx internal board zc1275 - "xlnx,zynqmp-zc1275-revA", "xlnx,zynqmp-zc1275" - -- Xilinx internal board zc1751 - "xlnx,zynqmp-zc1751" - -- Xilinx 96boards compatible board zcu100 - "xlnx,zynqmp-zcu100-revC", "xlnx,zynqmp-zcu100" - -- Xilinx evaluation board zcu102 - "xlnx,zynqmp-zcu102-revA", "xlnx,zynqmp-zcu102" - "xlnx,zynqmp-zcu102-revB", "xlnx,zynqmp-zcu102" - "xlnx,zynqmp-zcu102-rev1.0", "xlnx,zynqmp-zcu102" - -- Xilinx evaluation board zcu104 - "xlnx,zynqmp-zcu104-revA", "xlnx,zynqmp-zcu104" - -- Xilinx evaluation board zcu106 - "xlnx,zynqmp-zcu106-revA", "xlnx,zynqmp-zcu106" - -- Xilinx evaluation board zcu111 - "xlnx,zynqmp-zcu111-revA", "xlnx,zynqmp-zcu111" diff --git a/Documentation/devicetree/bindings/arm/xilinx.yaml b/Documentation/devicetree/bindings/arm/xilinx.yaml new file mode 100644 index 000000000000..c73b1f5c7f49 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/xilinx.yaml @@ -0,0 +1,114 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/xilinx.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Xilinx Zynq Platforms Device Tree Bindings + +maintainers: + - Michal Simek <michal.simek@xilinx.com> + +description: | + Xilinx boards with Zynq-7000 SOC or Zynq UltraScale+ MPSoC + +properties: + $nodename: + const: '/' + compatible: + oneOf: + - items: + - enum: + - adapteva,parallella + - digilent,zynq-zybo + - digilent,zynq-zybo-z7 + - xlnx,zynq-cc108 + - xlnx,zynq-zc702 + - xlnx,zynq-zc706 + - xlnx,zynq-zc770-xm010 + - xlnx,zynq-zc770-xm011 + - xlnx,zynq-zc770-xm012 + - xlnx,zynq-zc770-xm013 + - const: xlnx,zynq-7000 + + - items: + - const: avnet,zynq-microzed + - const: xlnx,zynq-microzed + - const: xlnx,zynq-7000 + + - items: + - const: avnet,zynq-zed + - const: xlnx,zynq-zed + - const: xlnx,zynq-7000 + + - items: + - enum: + - xlnx,zynqmp-zc1751 + - const: xlnx,zynqmp + + - description: Xilinx internal board zc1232 + items: + - const: xlnx,zynqmp-zc1232-revA + - const: xlnx,zynqmp-zc1232 + - const: xlnx,zynqmp + + - description: Xilinx internal board zc1254 + items: + - const: xlnx,zynqmp-zc1254-revA + - const: xlnx,zynqmp-zc1254 + - const: xlnx,zynqmp + + - description: Xilinx internal board zc1275 + items: + - const: xlnx,zynqmp-zc1275-revA + - const: xlnx,zynqmp-zc1275 + - const: xlnx,zynqmp + + - description: Xilinx 96boards compatible board zcu100 + items: + - const: xlnx,zynqmp-zcu100-revC + - const: xlnx,zynqmp-zcu100 + - const: xlnx,zynqmp + + - description: Xilinx 96boards compatible board Ultra96 + items: + - const: avnet,ultra96-rev1 + - const: avnet,ultra96 + - const: xlnx,zynqmp-zcu100-revC + - const: xlnx,zynqmp-zcu100 + - const: xlnx,zynqmp + + - description: Xilinx evaluation board zcu102 + items: + - enum: + - xlnx,zynqmp-zcu102-revA + - xlnx,zynqmp-zcu102-revB + - xlnx,zynqmp-zcu102-rev1.0 + - const: xlnx,zynqmp-zcu102 + - const: xlnx,zynqmp + + - description: Xilinx evaluation board zcu104 + items: + - enum: + - xlnx,zynqmp-zcu104-revA + - xlnx,zynqmp-zcu104-rev1.0 + - const: xlnx,zynqmp-zcu104 + - const: xlnx,zynqmp + + - description: Xilinx evaluation board zcu106 + items: + - enum: + - xlnx,zynqmp-zcu106-revA + - xlnx,zynqmp-zcu106-rev1.0 + - const: xlnx,zynqmp-zcu106 + - const: xlnx,zynqmp + + - description: Xilinx evaluation board zcu111 + items: + - enum: + - xlnx,zynqmp-zcu111-revA + - xlnx,zynqmp-zcu11-rev1.0 + - const: xlnx,zynqmp-zcu111 + - const: xlnx,zynqmp + +... diff --git a/Documentation/devicetree/bindings/arm/zte.txt b/Documentation/devicetree/bindings/arm/zte.txt deleted file mode 100644 index 340612794a37..000000000000 --- a/Documentation/devicetree/bindings/arm/zte.txt +++ /dev/null @@ -1,14 +0,0 @@ -ZTE platforms device tree bindings - ---------------------------------------- -- ZX296702 board: - Required root node properties: - - compatible = "zte,zx296702-ad1", "zte,zx296702" - ---------------------------------------- -- ZX296718 SoC: - Required root node properties: - - compatible = "zte,zx296718" - -ZX296718 EVB board: - - "zte,zx296718-evb" diff --git a/Documentation/devicetree/bindings/arm/zte.yaml b/Documentation/devicetree/bindings/arm/zte.yaml new file mode 100644 index 000000000000..2d3fefdccdff --- /dev/null +++ b/Documentation/devicetree/bindings/arm/zte.yaml @@ -0,0 +1,26 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/arm/zte.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: ZTE platforms device tree bindings + +maintainers: + - Jun Nie <jun.nie@linaro.org> + +properties: + $nodename: + const: '/' + compatible: + oneOf: + - items: + - enum: + - zte,zx296702-ad1 + - const: zte,zx296702 + - items: + - enum: + - zte,zx296718-evb + - const: zte,zx296718 + +... diff --git a/Documentation/devicetree/bindings/bus/ti-sysc.txt b/Documentation/devicetree/bindings/bus/ti-sysc.txt index 91dc2333af01..85a23f551f02 100644 --- a/Documentation/devicetree/bindings/bus/ti-sysc.txt +++ b/Documentation/devicetree/bindings/bus/ti-sysc.txt @@ -35,6 +35,7 @@ Required standard properties: "ti,sysc-omap3-sham" "ti,sysc-omap-aes" "ti,sysc-mcasp" + "ti,sysc-dra7-mcasp" "ti,sysc-usb-host-fs" "ti,sysc-dra7-mcan" diff --git a/Documentation/devicetree/bindings/clock/amlogic,gxbb-aoclkc.txt b/Documentation/devicetree/bindings/clock/amlogic,gxbb-aoclkc.txt index 3a880528030e..79511d7bb321 100644 --- a/Documentation/devicetree/bindings/clock/amlogic,gxbb-aoclkc.txt +++ b/Documentation/devicetree/bindings/clock/amlogic,gxbb-aoclkc.txt @@ -11,6 +11,13 @@ Required Properties: - GXM (S912) : "amlogic,meson-gxm-aoclkc" - AXG (A113D, A113X) : "amlogic,meson-axg-aoclkc" followed by the common "amlogic,meson-gx-aoclkc" +- clocks: list of clock phandle, one for each entry clock-names. +- clock-names: should contain the following: + * "xtal" : the platform xtal + * "mpeg-clk" : the main clock controller mother clock (aka clk81) + * "ext-32k-0" : external 32kHz reference #0 if any (optional) + * "ext-32k-1" : external 32kHz reference #1 if any (optional - gx only) + * "ext-32k-2" : external 32kHz reference #2 if any (optional - gx only) - #clock-cells: should be 1. @@ -40,8 +47,9 @@ ao_sysctrl: sys-ctrl@0 { compatible = "amlogic,meson-gxbb-aoclkc", "amlogic,meson-gx-aoclkc"; #clock-cells = <1>; #reset-cells = <1>; + clocks = <&xtal>, <&clkc CLKID_CLK81>; + clock-names = "xtal", "mpeg-clk"; }; -}; Example: UART controller node that consumes the clock and reset generated by the clock controller: diff --git a/Documentation/devicetree/bindings/clock/amlogic,gxbb-clkc.txt b/Documentation/devicetree/bindings/clock/amlogic,gxbb-clkc.txt index e950599566a9..a6871953bf04 100644 --- a/Documentation/devicetree/bindings/clock/amlogic,gxbb-clkc.txt +++ b/Documentation/devicetree/bindings/clock/amlogic,gxbb-clkc.txt @@ -9,6 +9,9 @@ Required Properties: "amlogic,gxbb-clkc" for GXBB SoC, "amlogic,gxl-clkc" for GXL and GXM SoC, "amlogic,axg-clkc" for AXG SoC. +- clocks : list of clock phandle, one for each entry clock-names. +- clock-names : should contain the following: + * "xtal": the platform xtal - #clock-cells: should be 1. @@ -31,6 +34,8 @@ sysctrl: system-controller@0 { clkc: clock-controller { #clock-cells = <1>; compatible = "amlogic,gxbb-clkc"; + clocks = <&xtal>; + clock-names = "xtal"; }; }; diff --git a/Documentation/devicetree/bindings/connector/usb-connector.txt b/Documentation/devicetree/bindings/connector/usb-connector.txt index d90e17e2428b..a9a2f2fc44f2 100644 --- a/Documentation/devicetree/bindings/connector/usb-connector.txt +++ b/Documentation/devicetree/bindings/connector/usb-connector.txt @@ -14,6 +14,8 @@ Optional properties: - label: symbolic name for the connector, - type: size of the connector, should be specified in case of USB-A, USB-B non-fullsize connectors: "mini", "micro". +- self-powered: Set this property if the usb device that has its own power + source. Optional properties for usb-c-connector: - power-role: should be one of "source", "sink" or "dual"(DRP) if typec diff --git a/Documentation/devicetree/bindings/crypto/arm-cryptocell.txt b/Documentation/devicetree/bindings/crypto/arm-cryptocell.txt index 999fb2a810f6..6130e6eb4af8 100644 --- a/Documentation/devicetree/bindings/crypto/arm-cryptocell.txt +++ b/Documentation/devicetree/bindings/crypto/arm-cryptocell.txt @@ -1,8 +1,12 @@ Arm TrustZone CryptoCell cryptographic engine Required properties: -- compatible: Should be one of: "arm,cryptocell-712-ree", - "arm,cryptocell-710-ree" or "arm,cryptocell-630p-ree". +- compatible: Should be one of - + "arm,cryptocell-713-ree" + "arm,cryptocell-703-ree" + "arm,cryptocell-712-ree" + "arm,cryptocell-710-ree" + "arm,cryptocell-630p-ree" - reg: Base physical address of the engine and length of memory mapped region. - interrupts: Interrupt number for the device. diff --git a/Documentation/devicetree/bindings/crypto/fsl-dcp.txt b/Documentation/devicetree/bindings/crypto/fsl-dcp.txt index 76a0b4e80e83..4e4d387e38a5 100644 --- a/Documentation/devicetree/bindings/crypto/fsl-dcp.txt +++ b/Documentation/devicetree/bindings/crypto/fsl-dcp.txt @@ -6,6 +6,8 @@ Required properties: - interrupts : Should contain MXS DCP interrupt numbers, VMI IRQ and DCP IRQ must be supplied, optionally Secure IRQ can be present, but is currently not implemented and not used. +- clocks : Clock reference (only required on some SOCs: 6ull and 6sll). +- clock-names : Must be "dcp". Example: diff --git a/Documentation/devicetree/bindings/dma/8250_mtk_dma.txt b/Documentation/devicetree/bindings/dma/8250_mtk_dma.txt new file mode 100644 index 000000000000..3fe0961bcf64 --- /dev/null +++ b/Documentation/devicetree/bindings/dma/8250_mtk_dma.txt @@ -0,0 +1,33 @@ +* Mediatek UART APDMA Controller + +Required properties: +- compatible should contain: + * "mediatek,mt2712-uart-dma" for MT2712 compatible APDMA + * "mediatek,mt6577-uart-dma" for MT6577 and all of the above + +- reg: The base address of the APDMA register bank. + +- interrupts: A single interrupt specifier. + +- clocks : Must contain an entry for each entry in clock-names. + See ../clocks/clock-bindings.txt for details. +- clock-names: The APDMA clock for register accesses + +Examples: + + apdma: dma-controller@11000380 { + compatible = "mediatek,mt2712-uart-dma"; + reg = <0 0x11000380 0 0x400>; + interrupts = <GIC_SPI 63 IRQ_TYPE_LEVEL_LOW>, + <GIC_SPI 64 IRQ_TYPE_LEVEL_LOW>, + <GIC_SPI 65 IRQ_TYPE_LEVEL_LOW>, + <GIC_SPI 66 IRQ_TYPE_LEVEL_LOW>, + <GIC_SPI 67 IRQ_TYPE_LEVEL_LOW>, + <GIC_SPI 68 IRQ_TYPE_LEVEL_LOW>, + <GIC_SPI 69 IRQ_TYPE_LEVEL_LOW>, + <GIC_SPI 70 IRQ_TYPE_LEVEL_LOW>; + clocks = <&pericfg CLK_PERI_AP_DMA>; + clock-names = "apdma"; + #dma-cells = <1>; + }; + diff --git a/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt b/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt index a5a7c3f5a1e3..5a512c5ea76a 100644 --- a/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt +++ b/Documentation/devicetree/bindings/dma/renesas,rcar-dmac.txt @@ -1,6 +1,6 @@ * Renesas R-Car (RZ/G) DMA Controller Device Tree bindings -Renesas R-Car Generation 2 SoCs have multiple multi-channel DMA +Renesas R-Car (Gen 2/3) and RZ/G SoCs have multiple multi-channel DMA controller instances named DMAC capable of serving multiple clients. Channels can be dedicated to specific clients or shared between a large number of clients. @@ -20,6 +20,8 @@ Required Properties: - "renesas,dmac-r8a7744" (RZ/G1N) - "renesas,dmac-r8a7745" (RZ/G1E) - "renesas,dmac-r8a77470" (RZ/G1C) + - "renesas,dmac-r8a774a1" (RZ/G2M) + - "renesas,dmac-r8a774c0" (RZ/G2E) - "renesas,dmac-r8a7790" (R-Car H2) - "renesas,dmac-r8a7791" (R-Car M2-W) - "renesas,dmac-r8a7792" (R-Car V2H) diff --git a/Documentation/devicetree/bindings/dma/renesas,usb-dmac.txt b/Documentation/devicetree/bindings/dma/renesas,usb-dmac.txt index 1743017bd948..372f0eeb5a2a 100644 --- a/Documentation/devicetree/bindings/dma/renesas,usb-dmac.txt +++ b/Documentation/devicetree/bindings/dma/renesas,usb-dmac.txt @@ -6,6 +6,9 @@ Required Properties: - "renesas,r8a7743-usb-dmac" (RZ/G1M) - "renesas,r8a7744-usb-dmac" (RZ/G1N) - "renesas,r8a7745-usb-dmac" (RZ/G1E) + - "renesas,r8a77470-usb-dmac" (RZ/G1C) + - "renesas,r8a774a1-usb-dmac" (RZ/G2M) + - "renesas,r8a774c0-usb-dmac" (RZ/G2E) - "renesas,r8a7790-usb-dmac" (R-Car H2) - "renesas,r8a7791-usb-dmac" (R-Car M2-W) - "renesas,r8a7793-usb-dmac" (R-Car M2-N) diff --git a/Documentation/devicetree/bindings/dma/snps-dma.txt b/Documentation/devicetree/bindings/dma/snps-dma.txt index 39e2b26be344..db757df7057d 100644 --- a/Documentation/devicetree/bindings/dma/snps-dma.txt +++ b/Documentation/devicetree/bindings/dma/snps-dma.txt @@ -27,6 +27,10 @@ Optional properties: general purpose DMA channel allocator. False if not passed. - multi-block: Multi block transfers supported by hardware. Array property with one cell per channel. 0: not supported, 1 (default): supported. +- snps,dma-protection-control: AHB HPROT[3:1] protection setting. + The default value is 0 (for non-cacheable, non-buffered, + unprivileged data access). + Refer to include/dt-bindings/dma/dw-dmac.h for possible values. Example: diff --git a/Documentation/devicetree/bindings/dma/uniphier-mio-dmac.txt b/Documentation/devicetree/bindings/dma/uniphier-mio-dmac.txt new file mode 100644 index 000000000000..b12388dc7eac --- /dev/null +++ b/Documentation/devicetree/bindings/dma/uniphier-mio-dmac.txt @@ -0,0 +1,25 @@ +UniPhier Media IO DMA controller + +This works as an external DMA engine for SD/eMMC controllers etc. +found in UniPhier LD4, Pro4, sLD8 SoCs. + +Required properties: +- compatible: should be "socionext,uniphier-mio-dmac". +- reg: offset and length of the register set for the device. +- interrupts: a list of interrupt specifiers associated with the DMA channels. +- clocks: a single clock specifier. +- #dma-cells: should be <1>. The single cell represents the channel index. + +Example: + dmac: dma-controller@5a000000 { + compatible = "socionext,uniphier-mio-dmac"; + reg = <0x5a000000 0x1000>; + interrupts = <0 68 4>, <0 68 4>, <0 69 4>, <0 70 4>, + <0 71 4>, <0 72 4>, <0 73 4>, <0 74 4>; + clocks = <&mio_clk 7>; + #dma-cells = <1>; + }; + +Note: +In the example above, "interrupts = <0 68 4>, <0 68 4>, ..." is not a typo. +The first two channels share a single interrupt line. diff --git a/Documentation/devicetree/bindings/example-schema.yaml b/Documentation/devicetree/bindings/example-schema.yaml new file mode 100644 index 000000000000..9175d67f355d --- /dev/null +++ b/Documentation/devicetree/bindings/example-schema.yaml @@ -0,0 +1,170 @@ +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) +# Copyright 2018 Linaro Ltd. +%YAML 1.2 +--- +# All the top-level keys are standard json-schema keywords except for +# 'maintainers' and 'select' + +# $id is a unique idenifier based on the filename. There may or may not be a +# file present at the URL. +$id: "http://devicetree.org/schemas/example-schema.yaml#" +# $schema is the meta-schema this schema should be validated with. +$schema: "http://devicetree.org/meta-schemas/core.yaml#" + +title: An example schema annotated with jsonschema details + +maintainers: + - Rob Herring <robh@kernel.org> + +description: | + A more detailed multi-line description of the binding. + + Details about the hardware device and any links to datasheets can go here. + + Literal blocks are marked with the '|' at the beginning. The end is marked by + indentation less than the first line of the literal block. Lines also cannot + begin with a tab character. + +select: false + # 'select' is a schema applied to a DT node to determine if this binding + # schema should be applied to the node. It is optional and by default the + # possible compatible strings are extracted and used to match. + + # In this case, a 'false' schema will never match. + +properties: + # A dictionary of DT properties for this binding schema + compatible: + # More complicated schema can use oneOf (XOR), anyOf (OR), or allOf (AND) + # to handle different conditions. + # In this case, it's needed to handle a variable number of values as there + # isn't another way to express a constraint of the last string value. + # The boolean schema must be a list of schemas. + oneOf: + - items: + # items is a list of possible values for the property. The number of + # values is determined by the number of elements in the list. + # Order in lists is significant, order in dicts is not + # Must be one of the 1st enums followed by the 2nd enum + # + # Each element in items should be 'enum' or 'const' + - enum: + - vendor,soc4-ip + - vendor,soc3-ip + - vendor,soc2-ip + - enum: + - vendor,soc1-ip + # additionalItems being false is implied + # minItems/maxItems equal to 2 is implied + - items: + # 'const' is just a special case of an enum with a single possible value + - const: vendor,soc1-ip + + reg: + # The core schema already checks that reg values are numbers, so device + # specific schema don't need to do those checks. + # The description of each element defines the order and implicitly defines + # the number of reg entries. + items: + - description: core registers + - description: aux registers + # minItems/maxItems equal to 2 is implied + + reg-names: + # The core schema enforces this is a string array + items: + - const: core + - const: aux + + clocks: + # Cases that have only a single entry just need to express that with maxItems + maxItems: 1 + description: bus clock + + clock-names: + items: + - const: bus + + interrupts: + # Either 1 or 2 interrupts can be present + minItems: 1 + maxItems: 2 + items: + - description: tx or combined interrupt + - description: rx interrupt + description: + A variable number of interrupts warrants a description of what conditions + affect the number of interrupts. Otherwise, descriptions on standard + properties are not necessary. + + interrupt-names: + # minItems must be specified here because the default would be 2 + minItems: 1 + maxItems: 2 + items: + - const: tx irq + - const: rx irq + + # Property names starting with '#' must be quoted + '#interrupt-cells': + # A simple case where the value must always be '2'. + # The core schema handles that this must be a single integer. + const: 2 + + interrupt-controller: true + # The core checks this is a boolean, so just have to list it here to be + # valid for this binding. + + clock-frequency: + # The type is set in the core schema. Per device schema only need to set + # constraints on the possible values. + minimum: 100 + maximum: 400000 + # The value that should be used if the property is not present + default: 200 + + foo-gpios: + maxItems: 1 + description: A connection of the 'foo' gpio line. + + vendor,int-property: + description: Vendor specific properties must have a description + # 'allOf' is the json-schema way of subclassing a schema. Here the base + # type schema is referenced and then additional constraints on the values + # are added. + allOf: + - $ref: /schemas/types.yaml#/definitions/uint32 + - enum: [2, 4, 6, 8, 10] + + vendor,bool-property: + description: Vendor specific properties must have a description + # boolean properties is one case where the json-schema 'type' keyword + # can be used directly + type: boolean + + vendor,string-array-property: + description: Vendor specific properties should reference a type in the + core schema. + allOf: + - $ref: /schemas/types.yaml#/definitions/string-array + - items: + - enum: [ foo, bar ] + - enum: [ baz, boo ] + +required: + - compatible + - reg + - interrupts + - interrupt-controller + +examples: + # Examples are now compiled with dtc + - | + node@1000 { + compatible = "vendor,soc4-ip", "vendor,soc1-ip"; + reg = <0x1000 0x80>, + <0x3000 0x80>; + reg-names = "core", "aux"; + interrupts = <10>; + interrupt-controller; + }; diff --git a/Documentation/devicetree/bindings/firmware/intel,stratix10-svc.txt b/Documentation/devicetree/bindings/firmware/intel,stratix10-svc.txt new file mode 100644 index 000000000000..1fa66065acc6 --- /dev/null +++ b/Documentation/devicetree/bindings/firmware/intel,stratix10-svc.txt @@ -0,0 +1,57 @@ +Intel Service Layer Driver for Stratix10 SoC +============================================ +Intel Stratix10 SoC is composed of a 64 bit quad-core ARM Cortex A53 hard +processor system (HPS) and Secure Device Manager (SDM). When the FPGA is +configured from HPS, there needs to be a way for HPS to notify SDM the +location and size of the configuration data. Then SDM will get the +configuration data from that location and perform the FPGA configuration. + +To meet the whole system security needs and support virtual machine requesting +communication with SDM, only the secure world of software (EL3, Exception +Layer 3) can interface with SDM. All software entities running on other +exception layers must channel through the EL3 software whenever it needs +service from SDM. + +Intel Stratix10 service layer driver, running at privileged exception level +(EL1, Exception Layer 1), interfaces with the service providers and provides +the services for FPGA configuration, QSPI, Crypto and warm reset. Service layer +driver also manages secure monitor call (SMC) to communicate with secure monitor +code running in EL3. + +Required properties: +------------------- +The svc node has the following mandatory properties, must be located under +the firmware node. + +- compatible: "intel,stratix10-svc" +- method: smc or hvc + smc - Secure Monitor Call + hvc - Hypervisor Call +- memory-region: + phandle to the reserved memory node. See + Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt + for details + +Example: +------- + + reserved-memory { + #address-cells = <2>; + #size-cells = <2>; + ranges; + + service_reserved: svcbuffer@0 { + compatible = "shared-dma-pool"; + reg = <0x0 0x0 0x0 0x1000000>; + alignment = <0x1000>; + no-map; + }; + }; + + firmware { + svc { + compatible = "intel,stratix10-svc"; + method = "smc"; + memory-region = <&service_reserved>; + }; + }; diff --git a/Documentation/devicetree/bindings/fpga/intel-stratix10-soc-fpga-mgr.txt b/Documentation/devicetree/bindings/fpga/intel-stratix10-soc-fpga-mgr.txt new file mode 100644 index 000000000000..6e03f79287fb --- /dev/null +++ b/Documentation/devicetree/bindings/fpga/intel-stratix10-soc-fpga-mgr.txt @@ -0,0 +1,17 @@ +Intel Stratix10 SoC FPGA Manager + +Required properties: +The fpga_mgr node has the following mandatory property, must be located under +firmware/svc node. + +- compatible : should contain "intel,stratix10-soc-fpga-mgr" + +Example: + + firmware { + svc { + fpga_mgr: fpga-mgr { + compatible = "intel,stratix10-soc-fpga-mgr"; + }; + }; + }; diff --git a/Documentation/devicetree/bindings/fsi/ibm,p9-occ.txt b/Documentation/devicetree/bindings/fsi/ibm,p9-occ.txt new file mode 100644 index 000000000000..99ca9862a586 --- /dev/null +++ b/Documentation/devicetree/bindings/fsi/ibm,p9-occ.txt @@ -0,0 +1,16 @@ +Device-tree bindings for FSI-attached POWER9 On-Chip Controller (OCC) +--------------------------------------------------------------------- + +This is the binding for the P9 On-Chip Controller accessed over FSI from a +service processor. See fsi.txt for details on bindings for FSI slave and CFAM +nodes. The OCC is not an FSI slave device itself, rather it is accessed +through the SBE fifo. + +Required properties: + - compatible = "ibm,p9-occ" + +Examples: + + occ { + compatible = "ibm,p9-occ"; + }; diff --git a/Documentation/devicetree/bindings/gpio/cdns,gpio.txt b/Documentation/devicetree/bindings/gpio/cdns,gpio.txt new file mode 100644 index 000000000000..706ef00f5c64 --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/cdns,gpio.txt @@ -0,0 +1,43 @@ +Cadence GPIO controller bindings + +Required properties: +- compatible: should be "cdns,gpio-r1p02". +- reg: the register base address and size. +- #gpio-cells: should be 2. + * first cell is the GPIO number. + * second cell specifies the GPIO flags, as defined in + <dt-bindings/gpio/gpio.h>. Only the GPIO_ACTIVE_HIGH + and GPIO_ACTIVE_LOW flags are supported. +- gpio-controller: marks the device as a GPIO controller. +- clocks: should contain one entry referencing the peripheral clock driving + the GPIO controller. + +Optional properties: +- ngpios: integer number of gpio lines supported by this controller, up to 32. +- interrupts: interrupt specifier for the controllers interrupt. +- interrupt-controller: marks the device as an interrupt controller. When + defined, interrupts, interrupt-parent and #interrupt-cells + are required. +- interrupt-cells: should be 2. + * first cell is the GPIO number you want to use as an IRQ source. + * second cell specifies the IRQ type, as defined in + <dt-bindings/interrupt-controller/irq.h>. + Currently only level sensitive IRQs are supported. + + +Example: + gpio0: gpio-controller@fd060000 { + compatible = "cdns,gpio-r1p02"; + reg =<0xfd060000 0x1000>; + + clocks = <&gpio_clk>; + + interrupt-parent = <&gic>; + interrupts = <0 5 IRQ_TYPE_LEVEL_HIGH>; + + gpio-controller; + #gpio-cells = <2>; + + interrupt-controller; + #interrupt-cells = <2>; + }; diff --git a/Documentation/devicetree/bindings/gpio/gpio-omap.txt b/Documentation/devicetree/bindings/gpio/gpio-omap.txt index 8d950522e7fa..e57b2cb28f6c 100644 --- a/Documentation/devicetree/bindings/gpio/gpio-omap.txt +++ b/Documentation/devicetree/bindings/gpio/gpio-omap.txt @@ -5,6 +5,8 @@ Required properties: - "ti,omap2-gpio" for OMAP2 controllers - "ti,omap3-gpio" for OMAP3 controllers - "ti,omap4-gpio" for OMAP4 controllers +- reg : Physical base address of the controller and length of memory mapped + region. - gpio-controller : Marks the device node as a GPIO controller. - #gpio-cells : Should be two. - first cell is the pin number @@ -18,6 +20,8 @@ Required properties: 2 = high-to-low edge triggered. 4 = active high level-sensitive. 8 = active low level-sensitive. +- interrupts : The interrupt the controller is rising as output when an + interrupt occures OMAP specific properties: - ti,hwmods: Name of the hwmod associated to the GPIO: @@ -29,11 +33,13 @@ OMAP specific properties: Example: -gpio4: gpio4 { +gpio0: gpio@44e07000 { compatible = "ti,omap4-gpio"; - ti,hwmods = "gpio4"; + reg = <0x44e07000 0x1000>; + ti,hwmods = "gpio1"; gpio-controller; #gpio-cells = <2>; interrupt-controller; #interrupt-cells = <2>; + interrupts = <96>; }; diff --git a/Documentation/devicetree/bindings/gpio/gpio-vf610.txt b/Documentation/devicetree/bindings/gpio/gpio-vf610.txt index 0ccbae44019c..ae254aadee35 100644 --- a/Documentation/devicetree/bindings/gpio/gpio-vf610.txt +++ b/Documentation/devicetree/bindings/gpio/gpio-vf610.txt @@ -24,6 +24,12 @@ Required properties for GPIO node: 4 = active high level-sensitive. 8 = active low level-sensitive. +Optional properties: +-clocks: Must contain an entry for each entry in clock-names. + See common clock-bindings.txt for details. +-clock-names: A list of clock names. For imx7ulp, it must contain + "gpio", "port". + Note: Each GPIO port should have an alias correctly numbered in "aliases" node. diff --git a/Documentation/devicetree/bindings/gpio/nxp,lpc1850-gpio.txt b/Documentation/devicetree/bindings/gpio/nxp,lpc1850-gpio.txt index eb7cdd69e10b..627efc78ecf2 100644 --- a/Documentation/devicetree/bindings/gpio/nxp,lpc1850-gpio.txt +++ b/Documentation/devicetree/bindings/gpio/nxp,lpc1850-gpio.txt @@ -3,12 +3,24 @@ NXP LPC18xx/43xx GPIO controller Device Tree Bindings Required properties: - compatible : Should be "nxp,lpc1850-gpio" -- reg : Address and length of the register set for the device -- clocks : Clock specifier (see clock bindings for details) -- gpio-controller : Marks the device node as a GPIO controller. -- #gpio-cells : Should be two - - First cell is the GPIO line number - - Second cell is used to specify polarity +- reg : List of addresses and lengths of the GPIO controller + register sets +- reg-names : Should be "gpio", "gpio-pin-ic", "gpio-group0-ic" and + "gpio-gpoup1-ic" +- clocks : Phandle and clock specifier pair for GPIO controller +- resets : Phandle and reset specifier pair for GPIO controller +- gpio-controller : Marks the device node as a GPIO controller +- #gpio-cells : Should be two: + - The first cell is the GPIO line number + - The second cell is used to specify polarity +- interrupt-controller : Marks the device node as an interrupt controller +- #interrupt-cells : Should be two: + - The first cell is an interrupt number within + 0..9 range, for GPIO pin interrupts it is equal + to 'nxp,gpio-pin-interrupt' property value of + GPIO pin configuration, 8 is for GPIO GROUP0 + interrupt, 9 is for GPIO GROUP1 interrupt + - The second cell is used to specify interrupt type Optional properties: - gpio-ranges : Mapping between GPIO and pinctrl @@ -19,21 +31,29 @@ Example: gpio: gpio@400f4000 { compatible = "nxp,lpc1850-gpio"; - reg = <0x400f4000 0x4000>; + reg = <0x400f4000 0x4000>, <0x40087000 0x1000>, + <0x40088000 0x1000>, <0x40089000 0x1000>; + reg-names = "gpio", "gpio-pin-ic", + "gpio-group0-ic", "gpio-gpoup1-ic"; clocks = <&ccu1 CLK_CPU_GPIO>; + resets = <&rgu 28>; gpio-controller; #gpio-cells = <2>; + interrupt-controller; + #interrupt-cells = <2>; gpio-ranges = <&pinctrl LPC_GPIO(0,0) LPC_PIN(0,0) 2>, ... <&pinctrl LPC_GPIO(7,19) LPC_PIN(f,5) 7>; }; gpio_joystick { - compatible = "gpio-keys-polled"; + compatible = "gpio-keys"; ... - button@0 { + button0 { ... + interrupt-parent = <&gpio>; + interrupts = <1 IRQ_TYPE_EDGE_BOTH>; gpios = <&gpio LPC_GPIO(4,8) GPIO_ACTIVE_LOW>; }; }; diff --git a/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt b/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt index 2889bbcd7416..f3f2c468c1b6 100644 --- a/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt +++ b/Documentation/devicetree/bindings/gpio/renesas,gpio-rcar.txt @@ -8,6 +8,7 @@ Required Properties: - "renesas,gpio-r8a7745": for R8A7745 (RZ/G1E) compatible GPIO controller. - "renesas,gpio-r8a77470": for R8A77470 (RZ/G1C) compatible GPIO controller. - "renesas,gpio-r8a774a1": for R8A774A1 (RZ/G2M) compatible GPIO controller. + - "renesas,gpio-r8a774c0": for R8A774C0 (RZ/G2E) compatible GPIO controller. - "renesas,gpio-r8a7778": for R8A7778 (R-Car M1) compatible GPIO controller. - "renesas,gpio-r8a7779": for R8A7779 (R-Car H1) compatible GPIO controller. - "renesas,gpio-r8a7790": for R8A7790 (R-Car H2) compatible GPIO controller. diff --git a/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt b/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt index 7276b50c3506..839dd32ffe11 100644 --- a/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt +++ b/Documentation/devicetree/bindings/gpio/snps-dwapb-gpio.txt @@ -43,7 +43,7 @@ gpio: gpio@20000 { #address-cells = <1>; #size-cells = <0>; - porta: gpio-controller@0 { + porta: gpio@0 { compatible = "snps,dw-apb-gpio-port"; gpio-controller; #gpio-cells = <2>; @@ -55,7 +55,7 @@ gpio: gpio@20000 { interrupts = <0>; }; - portb: gpio-controller@1 { + portb: gpio@1 { compatible = "snps,dw-apb-gpio-port"; gpio-controller; #gpio-cells = <2>; diff --git a/Documentation/devicetree/bindings/gpu/arm,mali-utgard.txt b/Documentation/devicetree/bindings/gpu/arm,mali-utgard.txt index 63cd91176a68..3f128e4f95c6 100644 --- a/Documentation/devicetree/bindings/gpu/arm,mali-utgard.txt +++ b/Documentation/devicetree/bindings/gpu/arm,mali-utgard.txt @@ -11,6 +11,7 @@ Required properties: + allwinner,sun4i-a10-mali + allwinner,sun7i-a20-mali + allwinner,sun8i-h3-mali + + allwinner,sun50i-a64-mali + allwinner,sun50i-h5-mali + amlogic,meson-gxbb-mali + amlogic,meson-gxl-mali @@ -73,6 +74,10 @@ to specify one more vendor-specific compatible, among: Required properties: * resets: phandle to the reset line for the GPU + - allwinner,sun50i-a64-mali + Required properties: + * resets: phandle to the reset line for the GPU + - allwinner,sun50i-h5-mali Required properties: * resets: phandle to the reset line for the GPU diff --git a/Documentation/devicetree/bindings/hwmon/adm1275.txt b/Documentation/devicetree/bindings/hwmon/adm1275.txt new file mode 100644 index 000000000000..1ecd03f3da4d --- /dev/null +++ b/Documentation/devicetree/bindings/hwmon/adm1275.txt @@ -0,0 +1,25 @@ +adm1275 properties + +Required properties: +- compatible: Must be one of the supported compatible strings: + - "adi,adm1075" for adm1075 + - "adi,adm1272" for adm1272 + - "adi,adm1275" for adm1275 + - "adi,adm1276" for adm1276 + - "adi,adm1278" for adm1278 + - "adi,adm1293" for adm1293 + - "adi,adm1294" for adm1294 +- reg: I2C address + +Optional properties: + +- shunt-resistor-micro-ohms + Shunt resistor value in micro-Ohm + +Example: + +adm1272@10 { + compatible = "adi,adm1272"; + reg = <0x10>; + shunt-resistor-micro-ohms = <500>; +}; diff --git a/Documentation/devicetree/bindings/hwmon/lm90.txt b/Documentation/devicetree/bindings/hwmon/lm90.txt index 97581266e329..c76a7ac47c34 100644 --- a/Documentation/devicetree/bindings/hwmon/lm90.txt +++ b/Documentation/devicetree/bindings/hwmon/lm90.txt @@ -23,6 +23,7 @@ Required node properties: "onnn,nct1008" "winbond,w83l771" "nxp,sa56004" + "ti,tmp451" - reg: I2C bus address of the device diff --git a/Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt b/Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt index c3b9c4cfe8df..37f18d684f6a 100644 --- a/Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt +++ b/Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt @@ -4,6 +4,7 @@ NTC Thermistor hwmon sensors Requires node properties: - "compatible" value : one of "epcos,b57330v2103" + "epcos,b57891s0103" "murata,ncp15wb473" "murata,ncp18wb473" "murata,ncp21wb473" diff --git a/Documentation/devicetree/bindings/hwmon/tmp108.txt b/Documentation/devicetree/bindings/hwmon/tmp108.txt index 8c4b10df86d9..54d4beed4ee5 100644 --- a/Documentation/devicetree/bindings/hwmon/tmp108.txt +++ b/Documentation/devicetree/bindings/hwmon/tmp108.txt @@ -7,6 +7,10 @@ Requires node properties: - compatible : "ti,tmp108" - reg : the I2C address of the device. This is 0x48, 0x49, 0x4a, or 0x4b. +Optional properties: +- interrupts: Reference to the TMP108 alert interrupt. +- #thermal-sensor-cells: should be set to 0. + Example: tmp108@48 { compatible = "ti,tmp108"; diff --git a/Documentation/devicetree/bindings/i2c/i2c-gpio.txt b/Documentation/devicetree/bindings/i2c/i2c-gpio.txt deleted file mode 100644 index 38a05562d1d2..000000000000 --- a/Documentation/devicetree/bindings/i2c/i2c-gpio.txt +++ /dev/null @@ -1,46 +0,0 @@ -Device-Tree bindings for i2c gpio driver - -Required properties: - - compatible = "i2c-gpio"; - - sda-gpios: gpio used for the sda signal, this should be flagged as - active high using open drain with (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN) - from <dt-bindings/gpio/gpio.h> since the signal is by definition - open drain. - - scl-gpios: gpio used for the scl signal, this should be flagged as - active high using open drain with (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN) - from <dt-bindings/gpio/gpio.h> since the signal is by definition - open drain. - -Optional properties: - - i2c-gpio,scl-output-only: scl as output only - - i2c-gpio,delay-us: delay between GPIO operations (may depend on each platform) - - i2c-gpio,timeout-ms: timeout to get data - -Deprecated properties, do not use in new device tree sources: - - gpios: sda and scl gpio, alternative for {sda,scl}-gpios - - i2c-gpio,sda-open-drain: this means that something outside of our - control has put the GPIO line used for SDA into open drain mode, and - that something is not the GPIO chip. It is essentially an - inconsistency flag. - - i2c-gpio,scl-open-drain: this means that something outside of our - control has put the GPIO line used for SCL into open drain mode, and - that something is not the GPIO chip. It is essentially an - inconsistency flag. - -Example nodes: - -#include <dt-bindings/gpio/gpio.h> - -i2c@0 { - compatible = "i2c-gpio"; - sda-gpios = <&pioA 23 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>; - scl-gpios = <&pioA 24 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>; - i2c-gpio,delay-us = <2>; /* ~100 kHz */ - #address-cells = <1>; - #size-cells = <0>; - - rv3029c2@56 { - compatible = "rv3029c2"; - reg = <0x56>; - }; -}; diff --git a/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml b/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml new file mode 100644 index 000000000000..da6129090a8e --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-gpio.yaml @@ -0,0 +1,73 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/i2c/i2c-gpio.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Bindings for GPIO bitbanged I2C + +maintainers: + - Wolfram Sang <wolfram@the-dreams.de> + +allOf: + - $ref: /schemas/i2c/i2c-controller.yaml# + +properties: + compatible: + items: + - const: i2c-gpio + + sda-gpios: + description: + gpio used for the sda signal, this should be flagged as + active high using open drain with (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN) + from <dt-bindings/gpio/gpio.h> since the signal is by definition + open drain. + maxItems: 1 + + scl-gpios: + description: + gpio used for the scl signal, this should be flagged as + active high using open drain with (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN) + from <dt-bindings/gpio/gpio.h> since the signal is by definition + open drain. + maxItems: 1 + + i2c-gpio,scl-output-only: + description: scl as output only + type: boolean + + i2c-gpio,delay-us: + description: delay between GPIO operations (may depend on each platform) + $ref: /schemas/types.yaml#/definitions/uint32 + + i2c-gpio,timeout-ms: + description: timeout to get data + $ref: /schemas/types.yaml#/definitions/uint32 + + # Deprecated properties, do not use in new device tree sources: + gpios: + minItems: 2 + maxItems: 2 + description: sda and scl gpio, alternative for {sda,scl}-gpios + + i2c-gpio,sda-open-drain: + # Generate a warning if present + not: true + description: this means that something outside of our control has put + the GPIO line used for SDA into open drain mode, and that something is + not the GPIO chip. It is essentially an inconsistency flag. + + i2c-gpio,scl-open-drain: + # Generate a warning if present + not: true + description: this means that something outside of our control has put the + GPIO line used for SCL into open drain mode, and that something is not + the GPIO chip. It is essentially an inconsistency flag. + +required: + - compatible + - sda-gpios + - scl-gpios + +... diff --git a/Documentation/devicetree/bindings/i2c/ibm,p8-occ-hwmon.txt b/Documentation/devicetree/bindings/i2c/ibm,p8-occ-hwmon.txt new file mode 100644 index 000000000000..5dc5d2e2573d --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/ibm,p8-occ-hwmon.txt @@ -0,0 +1,25 @@ +Device-tree bindings for I2C-based On-Chip Controller hwmon device +------------------------------------------------------------------ + +Required properties: + - compatible = "ibm,p8-occ-hwmon"; + - reg = <I2C address>; : I2C bus address + +Examples: + + i2c-bus@100 { + #address-cells = <1>; + #size-cells = <0>; + clock-frequency = <100000>; + < more properties > + + occ-hwmon@1 { + compatible = "ibm,p8-occ-hwmon"; + reg = <0x50>; + }; + + occ-hwmon@2 { + compatible = "ibm,p8-occ-hwmon"; + reg = <0x51>; + }; + }; diff --git a/Documentation/devicetree/bindings/iio/accel/lis302.txt b/Documentation/devicetree/bindings/iio/accel/lis302.txt index dfdce67826ba..764e28ec1a0a 100644 --- a/Documentation/devicetree/bindings/iio/accel/lis302.txt +++ b/Documentation/devicetree/bindings/iio/accel/lis302.txt @@ -64,7 +64,7 @@ Optional properties for all bus drivers: Example for a SPI device node: - lis302@0 { + accelerometer@0 { compatible = "st,lis302dl-spi"; reg = <0>; spi-max-frequency = <1000000>; @@ -89,7 +89,7 @@ Example for a SPI device node: Example for a I2C device node: - lis331dlh: lis331dlh@18 { + lis331dlh: accelerometer@18 { compatible = "st,lis331dlh", "st,lis3lv02d"; reg = <0x18>; Vdd-supply = <&lis3_reg>; diff --git a/Documentation/devicetree/bindings/iio/adc/ad7949.txt b/Documentation/devicetree/bindings/iio/adc/ad7949.txt new file mode 100644 index 000000000000..c7f5057356b1 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/adc/ad7949.txt @@ -0,0 +1,16 @@ +* Analog Devices AD7949/AD7682/AD7689 + +Required properties: + - compatible: Should be one of + * "adi,ad7949" + * "adi,ad7682" + * "adi,ad7689" + - reg: spi chip select number for the device + - vref-supply: The regulator supply for ADC reference voltage + +Example: +adc@0 { + compatible = "adi,ad7949"; + reg = <0>; + vref-supply = <&vdd_supply>; +}; diff --git a/Documentation/devicetree/bindings/iio/adc/adc.txt b/Documentation/devicetree/bindings/iio/adc/adc.txt new file mode 100644 index 000000000000..5bbaa330a250 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/adc/adc.txt @@ -0,0 +1,23 @@ +Common ADCs properties + +Optional properties for child nodes: +- bipolar : Boolean, if set the channel is used in bipolar mode. +- diff-channels : Differential channels muxed for this ADC. The first value + specifies the positive input pin, the second value the negative + input pin. + +Example: + adc@0 { + compatible = "some,adc"; + ... + channel@0 { + bipolar; + diff-channels = <0 1>; + ... + }; + + channel@1 { + diff-channels = <2 3>; + ... + }; + }; diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7124.txt b/Documentation/devicetree/bindings/iio/adc/adi,ad7124.txt new file mode 100644 index 000000000000..416273dce569 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7124.txt @@ -0,0 +1,75 @@ +Analog Devices AD7124 ADC device driver + +Required properties for the AD7124: + - compatible: Must be one of "adi,ad7124-4" or "adi,ad7124-8" + - reg: SPI chip select number for the device + - spi-max-frequency: Max SPI frequency to use + see: Documentation/devicetree/bindings/spi/spi-bus.txt + - clocks: phandle to the master clock (mclk) + see: Documentation/devicetree/bindings/clock/clock-bindings.txt + - clock-names: Must be "mclk". + - interrupts: IRQ line for the ADC + see: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt + + Required properties: + * #address-cells: Must be 1. + * #size-cells: Must be 0. + + Subnode(s) represent the external channels which are connected to the ADC. + Each subnode represents one channel and has the following properties: + Required properties: + * reg: The channel number. It can have up to 4 channels on ad7124-4 + and 8 channels on ad7124-8, numbered from 0 to 15. + * diff-channels: see: Documentation/devicetree/bindings/iio/adc/adc.txt + + Optional properties: + * bipolar: see: Documentation/devicetree/bindings/iio/adc/adc.txt + * adi,reference-select: Select the reference source to use when + converting on the the specific channel. Valid values are: + 0: REFIN1(+)/REFIN1(−). + 1: REFIN2(+)/REFIN2(−). + 3: AVDD + If this field is left empty, internal reference is selected. + +Optional properties: + - refin1-supply: refin1 supply can be used as reference for conversion. + - refin2-supply: refin2 supply can be used as reference for conversion. + - avdd-supply: avdd supply can be used as reference for conversion. + +Example: + adc@0 { + compatible = "adi,ad7124-4"; + reg = <0>; + spi-max-frequency = <5000000>; + interrupts = <25 2>; + interrupt-parent = <&gpio>; + refin1-supply = <&adc_vref>; + clocks = <&ad7124_mclk>; + clock-names = "mclk"; + + #address-cells = <1>; + #size-cells = <0>; + + channel@0 { + reg = <0>; + diff-channels = <0 1>; + adi,reference-select = <0>; + }; + + channel@1 { + reg = <1>; + bipolar; + diff-channels = <2 3>; + adi,reference-select = <0>; + }; + + channel@2 { + reg = <2>; + diff-channels = <4 5>; + }; + + channel@3 { + reg = <3>; + diff-channels = <6 7>; + }; + }; diff --git a/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt b/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt index 54b823f3a453..325090e43ce6 100644 --- a/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt +++ b/Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt @@ -22,6 +22,12 @@ Required properties: - vref-supply: the regulator supply for the ADC reference voltage - #io-channel-cells: must be 1, see ../iio-bindings.txt +Optional properties: +- nvmem-cells: phandle to the temperature_calib eFuse cells +- nvmem-cell-names: if present (to enable the temperature sensor + calibration) this must contain "temperature_calib" + + Example: saradc: adc@8680 { compatible = "amlogic,meson-gxl-saradc", "amlogic,meson-saradc"; diff --git a/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt index b3c86f4ac7cd..c81993f8d8c3 100644 --- a/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt +++ b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.txt @@ -140,6 +140,10 @@ VADC_GND_REF and VADC_VDD_VADC. Example: +#include <dt-bindings/iio/qcom,spmi-vadc.h> +#include <linux/irq.h> +/* ... */ + /* VADC node */ pmic_vadc: vadc@3100 { compatible = "qcom,spmi-vadc"; @@ -151,7 +155,7 @@ Example: io-channel-ranges; /* Channel node */ - usb_id_nopull { + adc-chan@VADC_LR_MUX10_USB_ID { reg = <VADC_LR_MUX10_USB_ID>; qcom,decimation = <512>; qcom,ratiometric; diff --git a/Documentation/devicetree/bindings/iio/adc/samsung,exynos-adc.txt b/Documentation/devicetree/bindings/iio/adc/samsung,exynos-adc.txt index 6c49db7f8ad2..a10c1f89037d 100644 --- a/Documentation/devicetree/bindings/iio/adc/samsung,exynos-adc.txt +++ b/Documentation/devicetree/bindings/iio/adc/samsung,exynos-adc.txt @@ -11,7 +11,7 @@ New driver handles the following Required properties: - compatible: Must be "samsung,exynos-adc-v1" - for exynos4412/5250 and s5pv210 controllers. + for exynos4412/5250 controllers. Must be "samsung,exynos-adc-v2" for future controllers. Must be "samsung,exynos3250-adc" for @@ -28,6 +28,8 @@ Required properties: the ADC in s3c2443 and compatibles Must be "samsung,s3c6410-adc" for the ADC in s3c6410 and compatibles + Must be "samsung,s5pv210-adc" for + the ADC in s5pv210 and compatibles - reg: List of ADC register address range - The base address and range of ADC register - The base address and range of ADC_PHY register (every diff --git a/Documentation/devicetree/bindings/iio/adc/ti-adc128s052.txt b/Documentation/devicetree/bindings/iio/adc/ti-adc128s052.txt index daa2b2c29428..c07ce1a3f5c4 100644 --- a/Documentation/devicetree/bindings/iio/adc/ti-adc128s052.txt +++ b/Documentation/devicetree/bindings/iio/adc/ti-adc128s052.txt @@ -1,7 +1,14 @@ * Texas Instruments' ADC128S052, ADC122S021 and ADC124S021 ADC chip Required properties: - - compatible: Should be "ti,adc128s052", "ti,adc122s021" or "ti,adc124s021" + - compatible: Should be one of: + - "ti,adc128s052" + - "ti,adc122s021" + - "ti,adc122s051" + - "ti,adc122s101" + - "ti,adc124s021" + - "ti,adc124s051" + - "ti,adc124s101" - reg: spi chip select number for the device - vref-supply: The regulator supply for ADC reference voltage diff --git a/Documentation/devicetree/bindings/iio/dac/ti,dac7311.txt b/Documentation/devicetree/bindings/iio/dac/ti,dac7311.txt new file mode 100644 index 000000000000..e5a507db5e01 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/dac/ti,dac7311.txt @@ -0,0 +1,23 @@ +TI DAC7311 device tree bindings + +Required properties: +- compatible: must be set to: + * "ti,dac7311" + * "ti,dac6311" + * "ti,dac5311" +- reg: spi chip select number for the device +- vref-supply: The regulator supply for ADC reference voltage + +Optional properties: +- spi-max-frequency: Max SPI frequency to use + +Example: + + spi_master { + dac@0 { + compatible = "ti,dac7311"; + reg = <0>; /* CS0 */ + spi-max-frequency = <1000000>; + vref-supply = <&vdd_supply>; + }; + }; diff --git a/Documentation/devicetree/bindings/iio/imu/st_lsm6dsx.txt b/Documentation/devicetree/bindings/iio/imu/st_lsm6dsx.txt index 879322ad50fd..69d53d98d0f0 100644 --- a/Documentation/devicetree/bindings/iio/imu/st_lsm6dsx.txt +++ b/Documentation/devicetree/bindings/iio/imu/st_lsm6dsx.txt @@ -13,6 +13,7 @@ Required properties: Optional properties: - st,drdy-int-pin: the pin on the package that will be used to signal "data ready" (valid values: 1 or 2). +- st,pullups : enable/disable internal i2c controller pullup resistors. - drive-open-drain: the interrupt/data ready line will be configured as open drain, which is useful if several sensors share the same interrupt line. This is a boolean property. diff --git a/Documentation/devicetree/bindings/iio/light/vcnl4035.txt b/Documentation/devicetree/bindings/iio/light/vcnl4035.txt new file mode 100644 index 000000000000..c07c7f052556 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/light/vcnl4035.txt @@ -0,0 +1,18 @@ +VISHAY VCNL4035 - Ambient Light and proximity sensor + +Link to datasheet: https://www.vishay.com/docs/84251/vcnl4035x01.pdf + +Required properties: + + -compatible: should be "vishay,vcnl4035" + -reg: I2C address of the sensor, should be 0x60 + -interrupts: interrupt mapping for GPIO IRQ (level active low) + +Example: + +light-sensor@60 { + compatible = "vishay,vcnl4035"; + reg = <0x60>; + interrupt-parent = <&gpio4>; + interrupts = <11 IRQ_TYPE_LEVEL_LOW>; +}; diff --git a/Documentation/devicetree/bindings/iio/magnetometer/mag3110.txt b/Documentation/devicetree/bindings/iio/magnetometer/mag3110.txt new file mode 100644 index 000000000000..bdd40bcaaa1f --- /dev/null +++ b/Documentation/devicetree/bindings/iio/magnetometer/mag3110.txt @@ -0,0 +1,27 @@ +* FREESCALE MAG3110 magnetometer sensor + +Required properties: + + - compatible : should be "fsl,mag3110" + - reg : the I2C address of the magnetometer + +Optional properties: + + - interrupts: the sole interrupt generated by the device + + Refer to interrupt-controller/interrupts.txt for generic interrupt client + node bindings. + + - vdd-supply: phandle to the regulator that provides power to the sensor. + - vddio-supply: phandle to the regulator that provides power to the sensor's IO. + +Example: + +magnetometer@e { + compatible = "fsl,mag3110"; + reg = <0x0e>; + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_i2c3_mag3110_int>; + interrupt-parent = <&gpio3>; + interrupts = <16 IRQ_TYPE_EDGE_RISING>; +}; diff --git a/Documentation/devicetree/bindings/iio/magnetometer/pni,rm3100.txt b/Documentation/devicetree/bindings/iio/magnetometer/pni,rm3100.txt new file mode 100644 index 000000000000..497c932e9e39 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/magnetometer/pni,rm3100.txt @@ -0,0 +1,20 @@ +* PNI RM3100 3-axis magnetometer sensor + +Required properties: + +- compatible : should be "pni,rm3100" +- reg : the I2C address or SPI chip select number of the sensor. + +Optional properties: + +- interrupts: data ready (DRDY) from the chip. + The interrupts can be triggered on level high. + +Example: + +rm3100: rm3100@20 { + compatible = "pni,rm3100"; + reg = <0x20>; + interrupt-parent = <&gpio0>; + interrupts = <4 IRQ_TYPE_LEVEL_HIGH>; +}; diff --git a/Documentation/devicetree/bindings/iio/potentiometer/mcp41010.txt b/Documentation/devicetree/bindings/iio/potentiometer/mcp41010.txt new file mode 100644 index 000000000000..566711b9950c --- /dev/null +++ b/Documentation/devicetree/bindings/iio/potentiometer/mcp41010.txt @@ -0,0 +1,28 @@ +* Microchip MCP41010/41050/41100/42010/42050/42100 Digital Potentiometer + +Datasheet publicly available at: +http://ww1.microchip.com/downloads/en/devicedoc/11195c.pdf + +The node for this driver must be a child node of a SPI controller, hence +all mandatory properties described in + + Documentation/devicetree/bindings/spi/spi-bus.txt + +must be specified. + +Required properties: + - compatible: Must be one of the following, depending on the + model: + "microchip,mcp41010" + "microchip,mcp41050" + "microchip,mcp41100" + "microchip,mcp42010" + "microchip,mcp42050" + "microchip,mcp42100" + +Example: +potentiometer@0 { + compatible = "microchip,mcp41010"; + reg = <0>; + spi-max-frequency = <500000>; +}; diff --git a/Documentation/devicetree/bindings/iio/resolver/ad2s90.txt b/Documentation/devicetree/bindings/iio/resolver/ad2s90.txt new file mode 100644 index 000000000000..477d41fa6467 --- /dev/null +++ b/Documentation/devicetree/bindings/iio/resolver/ad2s90.txt @@ -0,0 +1,31 @@ +Analog Devices AD2S90 Resolver-to-Digital Converter + +https://www.analog.com/en/products/ad2s90.html + +Required properties: + - compatible: should be "adi,ad2s90" + - reg: SPI chip select number for the device + - spi-max-frequency: set maximum clock frequency, must be 830000 + - spi-cpol and spi-cpha: + Either SPI mode (0,0) or (1,1) must be used, so specify none or both of + spi-cpha, spi-cpol. + +See for more details: + Documentation/devicetree/bindings/spi/spi-bus.txt + +Note about max frequency: + Chip's max frequency, as specified in its datasheet, is 2Mhz. But a 600ns + delay is expected between the application of a logic LO to CS and the + application of SCLK, as also specified. And since the delay is not + implemented in the spi code, to satisfy it, SCLK's period should be at most + 2 * 600ns, so the max frequency should be 1 / (2 * 6e-7), which gives + roughly 830000Hz. + +Example: +resolver@0 { + compatible = "adi,ad2s90"; + reg = <0>; + spi-max-frequency = <830000>; + spi-cpol; + spi-cpha; +}; diff --git a/Documentation/devicetree/bindings/iio/st-sensors.txt b/Documentation/devicetree/bindings/iio/st-sensors.txt index 6f626f73417e..ddcb95509599 100644 --- a/Documentation/devicetree/bindings/iio/st-sensors.txt +++ b/Documentation/devicetree/bindings/iio/st-sensors.txt @@ -48,6 +48,7 @@ Accelerometers: - st,lis3l02dq - st,lis2dw12 - st,lis3dhh +- st,lis3de Gyroscopes: - st,l3g4200d-gyro @@ -67,6 +68,7 @@ Magnetometers: - st,lsm303dlm-magn - st,lis3mdl-magn - st,lis2mdl +- st,lsm9ds1-magn Pressure sensors: - st,lps001wp-press diff --git a/Documentation/devicetree/bindings/input/touchscreen/raspberrypi,firmware-ts.txt b/Documentation/devicetree/bindings/input/touchscreen/raspberrypi,firmware-ts.txt new file mode 100644 index 000000000000..2a1af240ccc3 --- /dev/null +++ b/Documentation/devicetree/bindings/input/touchscreen/raspberrypi,firmware-ts.txt @@ -0,0 +1,26 @@ +Raspberry Pi firmware based 7" touchscreen +===================================== + +Required properties: + - compatible: "raspberrypi,firmware-ts" + +Optional properties: + - firmware: Reference to RPi's firmware device node + - touchscreen-size-x: See touchscreen.txt + - touchscreen-size-y: See touchscreen.txt + - touchscreen-inverted-x: See touchscreen.txt + - touchscreen-inverted-y: See touchscreen.txt + - touchscreen-swapped-x-y: See touchscreen.txt + +Example: + +firmware: firmware-rpi { + compatible = "raspberrypi,bcm2835-firmware"; + mboxes = <&mailbox>; + + ts: touchscreen { + compatible = "raspberrypi,firmware-ts"; + touchscreen-size-x = <800>; + touchscreen-size-y = <480>; + }; +}; diff --git a/Documentation/devicetree/bindings/interrupt-controller/mrvl,intc.txt b/Documentation/devicetree/bindings/interrupt-controller/mrvl,intc.txt index 8b53273cb22f..608fee15a4cf 100644 --- a/Documentation/devicetree/bindings/interrupt-controller/mrvl,intc.txt +++ b/Documentation/devicetree/bindings/interrupt-controller/mrvl,intc.txt @@ -5,7 +5,7 @@ Required properties: "mrvl,mmp2-mux-intc" - reg : Address and length of the register set of the interrupt controller. If the interrupt controller is intc, address and length means the range - of the whold interrupt controller. If the interrupt controller is mux-intc, + of the whole interrupt controller. If the interrupt controller is mux-intc, address and length means one register. Since address of mux-intc is in the range of intc. mux-intc is secondary interrupt controller. - reg-names : Name of the register set of the interrupt controller. It's diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt b/Documentation/devicetree/bindings/iommu/arm,smmu.txt index 8a6ffce12af5..3133f3ba7567 100644 --- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt @@ -17,10 +17,20 @@ conditions. "arm,mmu-401" "arm,mmu-500" "cavium,smmu-v2" + "qcom,smmu-v2" depending on the particular implementation and/or the version of the architecture implemented. + Qcom SoCs must contain, as below, SoC-specific compatibles + along with "qcom,smmu-v2": + "qcom,msm8996-smmu-v2", "qcom,smmu-v2", + "qcom,sdm845-smmu-v2", "qcom,smmu-v2". + + Qcom SoCs implementing "arm,mmu-500" must also include, + as below, SoC-specific compatibles: + "qcom,sdm845-smmu-500", "arm,mmu-500" + - reg : Base address and size of the SMMU. - #global-interrupts : The number of global interrupts exposed by the @@ -71,6 +81,22 @@ conditions. or using stream matching with #iommu-cells = <2>, and may be ignored if present in such cases. +- clock-names: List of the names of clocks input to the device. The + required list depends on particular implementation and + is as follows: + - for "qcom,smmu-v2": + - "bus": clock required for downstream bus access and + for the smmu ptw, + - "iface": clock required to access smmu's registers + through the TCU's programming interface. + - unspecified for other implementations. + +- clocks: Specifiers for all clocks listed in the clock-names property, + as per generic clock bindings. + +- power-domains: Specifiers for power domains required to be powered on for + the SMMU to operate, as per generic power domain bindings. + ** Deprecated properties: - mmu-masters (deprecated in favour of the generic "iommus" binding) : @@ -137,3 +163,20 @@ conditions. iommu-map = <0 &smmu3 0 0x400>; ... }; + + /* Qcom's arm,smmu-v2 implementation */ + smmu4: iommu@d00000 { + compatible = "qcom,msm8996-smmu-v2", "qcom,smmu-v2"; + reg = <0xd00000 0x10000>; + + #global-interrupts = <1>; + interrupts = <GIC_SPI 73 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 320 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 321 IRQ_TYPE_LEVEL_HIGH>; + #iommu-cells = <1>; + power-domains = <&mmcc MDSS_GDSC>; + + clocks = <&mmcc SMMU_MDP_AXI_CLK>, + <&mmcc SMMU_MDP_AHB_CLK>; + clock-names = "bus", "iface"; + }; diff --git a/Documentation/devicetree/bindings/iommu/renesas,ipmmu-vmsa.txt b/Documentation/devicetree/bindings/iommu/renesas,ipmmu-vmsa.txt index 377ee639d103..b6bfbec3a849 100644 --- a/Documentation/devicetree/bindings/iommu/renesas,ipmmu-vmsa.txt +++ b/Documentation/devicetree/bindings/iommu/renesas,ipmmu-vmsa.txt @@ -14,6 +14,8 @@ Required Properties: - "renesas,ipmmu-r8a7743" for the R8A7743 (RZ/G1M) IPMMU. - "renesas,ipmmu-r8a7744" for the R8A7744 (RZ/G1N) IPMMU. - "renesas,ipmmu-r8a7745" for the R8A7745 (RZ/G1E) IPMMU. + - "renesas,ipmmu-r8a774a1" for the R8A774A1 (RZ/G2M) IPMMU. + - "renesas,ipmmu-r8a774c0" for the R8A774C0 (RZ/G2E) IPMMU. - "renesas,ipmmu-r8a7790" for the R8A7790 (R-Car H2) IPMMU. - "renesas,ipmmu-r8a7791" for the R8A7791 (R-Car M2-W) IPMMU. - "renesas,ipmmu-r8a7793" for the R8A7793 (R-Car M2-N) IPMMU. diff --git a/Documentation/devicetree/bindings/mailbox/nvidia,tegra186-hsp.txt b/Documentation/devicetree/bindings/mailbox/nvidia,tegra186-hsp.txt index b99d25fc2f26..ff3eafc5a882 100644 --- a/Documentation/devicetree/bindings/mailbox/nvidia,tegra186-hsp.txt +++ b/Documentation/devicetree/bindings/mailbox/nvidia,tegra186-hsp.txt @@ -15,12 +15,15 @@ Required properties: Array of strings. one of: - "nvidia,tegra186-hsp" + - "nvidia,tegra194-hsp", "nvidia,tegra186-hsp" - reg : Offset and length of the register set for the device. - interrupt-names Array of strings. Contains a list of names for the interrupts described by the interrupt property. May contain the following entries, in any order: - "doorbell" + - "sharedN", where 'N' is a number from zero up to the number of + external interrupts supported by the HSP instance minus one. Users of this binding MUST look up entries in the interrupt property by name, using this interrupt-names property to do so. - interrupts @@ -29,12 +32,29 @@ Required properties: in a matching order. - #mbox-cells : Should be 2. -The mbox specifier of the "mboxes" property in the client node should -contain two data. The first one should be the HSP type and the second -one should be the ID that the client is going to use. Those information -can be found in the following file. +The mbox specifier of the "mboxes" property in the client node should contain +two cells. The first cell determines the HSP type and the second cell is used +to identify the mailbox that the client is going to use. -- <dt-bindings/mailbox/tegra186-hsp.h>. +For doorbells, the second cell specifies the index of the doorbell to use. + +For shared mailboxes, the second cell is composed of two fields: +- bits 31..24: + A bit mask of flags that further specify how the shared mailbox will be + used. Valid flags are: + - bit 31: + Defines the direction of the mailbox. If set, the mailbox will be used + as a producer (i.e. used to send data). If cleared, the mailbox is the + consumer of data sent by a producer. + +- bits 23.. 0: + The index of the shared mailbox to use. The number of available mailboxes + may vary by instance of the HSP block and SoC generation. + +The following file contains definitions that can be used to construct mailbox +specifiers: + + <dt-bindings/mailbox/tegra186-hsp.h> Example: diff --git a/Documentation/devicetree/bindings/media/cedrus.txt b/Documentation/devicetree/bindings/media/cedrus.txt index b3c0635dcd0e..bce0705df953 100644 --- a/Documentation/devicetree/bindings/media/cedrus.txt +++ b/Documentation/devicetree/bindings/media/cedrus.txt @@ -33,7 +33,7 @@ reserved-memory { ranges; /* Address must be kept in the lower 256 MiBs of DRAM for VE. */ - cma_pool: cma@4a000000 { + cma_pool: default-pool { compatible = "shared-dma-pool"; size = <0x6000000>; alloc-ranges = <0x4a000000 0x6000000>; diff --git a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-emc.txt b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt index 4c33b29dc660..add95367640b 100644 --- a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-emc.txt +++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-emc.txt @@ -10,6 +10,8 @@ Properties: and chosen using the ramcode board selector. If omitted, only one set of tables can be present and said tables will be used irrespective of ram-code configuration. +- interrupts : Should contain EMC General interrupt. +- clocks : Should contain EMC clock. Child device nodes describe the memory settings for different configurations and clock rates. @@ -20,6 +22,8 @@ Example: #size-cells = < 0 >; compatible = "nvidia,tegra20-emc"; reg = <0x7000f4000 0x200>; + interrupts = <0 78 0x04>; + clocks = <&tegra_car TEGRA20_CLK_EMC>; } diff --git a/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt b/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt index 01fdc33a41d0..bb7e896cb644 100644 --- a/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt +++ b/Documentation/devicetree/bindings/misc/fsl,qoriq-mc.txt @@ -10,7 +10,7 @@ such as network interfaces, crypto accelerator instances, L2 switches, etc. For an overview of the DPAA2 architecture and fsl-mc bus see: -Documentation/networking/dpaa2/overview.rst +Documentation/networking/device_drivers/freescale/dpaa2/overview.rst As described in the above overview, all DPAA2 objects in a DPRC share the same hardware "isolation context" and a 10-bit value called an ICID diff --git a/Documentation/devicetree/bindings/misc/pvpanic-mmio.txt b/Documentation/devicetree/bindings/misc/pvpanic-mmio.txt new file mode 100644 index 000000000000..985e90736780 --- /dev/null +++ b/Documentation/devicetree/bindings/misc/pvpanic-mmio.txt @@ -0,0 +1,29 @@ +* QEMU PVPANIC MMIO Configuration bindings + +QEMU's emulation / virtualization targets provide the following PVPANIC +MMIO Configuration interface on the "virt" machine. +type: + +- a read-write, 16-bit wide data register. + +QEMU exposes the data register to guests as memory mapped registers. + +Required properties: + +- compatible: "qemu,pvpanic-mmio". +- reg: the MMIO region used by the device. + * Bytes 0x0 Write panic event to the reg when guest OS panics. + * Bytes 0x1 Reserved. + +Example: + +/ { + #size-cells = <0x2>; + #address-cells = <0x2>; + + pvpanic-mmio@9060000 { + compatible = "qemu,pvpanic-mmio"; + reg = <0x0 0x9060000 0x0 0x2>; + }; +}; + diff --git a/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt b/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt index e2effe17f05e..1edbb049cccb 100644 --- a/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt +++ b/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt @@ -16,6 +16,10 @@ Required Properties: - "rockchip,rk3399-sdhci-5.1", "arasan,sdhci-5.1": rk3399 eMMC PHY For this device it is strongly suggested to include arasan,soc-ctl-syscon. - "ti,am654-sdhci-5.1", "arasan,sdhci-5.1": TI AM654 MMC PHY + Note: This binding has been deprecated and moved to [5]. + + [5] Documentation/devicetree/bindings/mmc/sdhci-am654.txt + - reg: From mmc bindings: Register location and length. - clocks: From clock bindings: Handles to clock inputs. - clock-names: From clock bindings: Tuple including "clk_xin" and "clk_ahb" diff --git a/Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt b/Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt index 3e29050ec769..9201a7d8d7b0 100644 --- a/Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt +++ b/Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.txt @@ -16,6 +16,7 @@ Required properties: "fsl,imx6sl-usdhc" "fsl,imx6sx-usdhc" "fsl,imx7d-usdhc" + "fsl,imx8qxp-usdhc" Optional properties: - fsl,wp-controller : Indicate to use controller internal write protection diff --git a/Documentation/devicetree/bindings/mmc/sdhci-am654.txt b/Documentation/devicetree/bindings/mmc/sdhci-am654.txt new file mode 100644 index 000000000000..15dbbbace27e --- /dev/null +++ b/Documentation/devicetree/bindings/mmc/sdhci-am654.txt @@ -0,0 +1,36 @@ +Device Tree Bindings for the SDHCI Controllers present on TI's AM654 SOCs + +The bindings follow the mmc[1], clock[2] and interrupt[3] bindings. +Only deviations are documented here. + + [1] Documentation/devicetree/bindings/mmc/mmc.txt + [2] Documentation/devicetree/bindings/clock/clock-bindings.txt + [3] Documentation/devicetree/bindings/interrupt-controller/interrupts.txt + +Required Properties: + - compatible: should be "ti,am654-sdhci-5.1" + - reg: Must be two entries. + - The first should be the sdhci register space + - The second should the subsystem/phy register space + - clocks: Handles to the clock inputs. + - clock-names: Tuple including "clk_xin" and "clk_ahb" + - interrupts: Interrupt specifiers + - ti,otap-del-sel: Output Tap Delay select + - ti,trm-icp: DLL trim select + - ti,driver-strength-ohm: driver strength in ohms. + Valid values are 33, 40, 50, 66 and 100 ohms. + +Example: + + sdhci0: sdhci@4f80000 { + compatible = "ti,am654-sdhci-5.1"; + reg = <0x0 0x4f80000 0x0 0x260>, <0x0 0x4f90000 0x0 0x134>; + power-domains = <&k3_pds 47>; + clocks = <&k3_clks 47 0>, <&k3_clks 47 1>; + clock-names = "clk_ahb", "clk_xin"; + interrupts = <GIC_SPI 136 IRQ_TYPE_LEVEL_HIGH>; + sdhci-caps-mask = <0x80000007 0x0>; + mmc-ddr-1_8v; + ti,otap-del-sel = <0x2>; + ti,trm-icp = <0x8>; + }; diff --git a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt index 502b3b851ebb..da4edb146a98 100644 --- a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt +++ b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt @@ -4,15 +4,28 @@ This file documents differences between the core properties in mmc.txt and the properties used by the sdhci-msm driver. Required properties: -- compatible: Should contain: +- compatible: Should contain a SoC-specific string and a IP version string: + version strings: "qcom,sdhci-msm-v4" for sdcc versions less than 5.0 - "qcom,sdhci-msm-v5" for sdcc versions >= 5.0 + "qcom,sdhci-msm-v5" for sdcc version 5.0 For SDCC version 5.0.0, MCI registers are removed from SDCC interface and some registers are moved to HC. New compatible string is added to support this change - "qcom,sdhci-msm-v5". + full compatible strings with SoC and version: + "qcom,apq8084-sdhci", "qcom,sdhci-msm-v4" + "qcom,msm8974-sdhci", "qcom,sdhci-msm-v4" + "qcom,msm8916-sdhci", "qcom,sdhci-msm-v4" + "qcom,msm8992-sdhci", "qcom,sdhci-msm-v4" + "qcom,msm8996-sdhci", "qcom,sdhci-msm-v4" + "qcom,sdm845-sdhci", "qcom,sdhci-msm-v5" + "qcom,qcs404-sdhci", "qcom,sdhci-msm-v5" + NOTE that some old device tree files may be floating around that only + have the string "qcom,sdhci-msm-v4" without the SoC compatible string + but doing that should be considered a deprecated practice. + - reg: Base address and length of the register in the following order: - Host controller register map (required) - - SD Core register map (required) + - SD Core register map (required for msm-v4 and below) - interrupts: Should contain an interrupt-specifiers for the interrupts: - Host controller interrupt (required) - pinctrl-names: Should contain only one value - "default". @@ -29,7 +42,7 @@ Required properties: Example: sdhc_1: sdhci@f9824900 { - compatible = "qcom,sdhci-msm-v4"; + compatible = "qcom,msm8974-sdhci", "qcom,sdhci-msm-v4"; reg = <0xf9824900 0x11c>, <0xf9824000 0x800>; interrupts = <0 123 0>; bus-width = <8>; @@ -46,7 +59,7 @@ Example: }; sdhc_2: sdhci@f98a4900 { - compatible = "qcom,sdhci-msm-v4"; + compatible = "qcom,msm8974-sdhci", "qcom,sdhci-msm-v4"; reg = <0xf98a4900 0x11c>, <0xf98a4000 0x800>; interrupts = <0 125 0>; bus-width = <4>; diff --git a/Documentation/devicetree/bindings/mmc/sdhci-omap.txt b/Documentation/devicetree/bindings/mmc/sdhci-omap.txt index 393848c2138e..72c4dec7e1db 100644 --- a/Documentation/devicetree/bindings/mmc/sdhci-omap.txt +++ b/Documentation/devicetree/bindings/mmc/sdhci-omap.txt @@ -2,6 +2,8 @@ Refer to mmc.txt for standard MMC bindings. +For UHS devices which require tuning, the device tree should have a "cpu_thermal" node which maps to the appropriate thermal zone. This is used to get the temperature of the zone during tuning. + Required properties: - compatible: Should be "ti,dra7-sdhci" for DRA7 and DRA72 controllers Should be "ti,k2g-sdhci" for K2G diff --git a/Documentation/devicetree/bindings/mmc/tmio_mmc.txt b/Documentation/devicetree/bindings/mmc/tmio_mmc.txt index 27f2eab2981d..2b4f17ca9087 100644 --- a/Documentation/devicetree/bindings/mmc/tmio_mmc.txt +++ b/Documentation/devicetree/bindings/mmc/tmio_mmc.txt @@ -13,12 +13,14 @@ Required properties: - compatible: should contain one or more of the following: "renesas,sdhi-sh73a0" - SDHI IP on SH73A0 SoC "renesas,sdhi-r7s72100" - SDHI IP on R7S72100 SoC + "renesas,sdhi-r7s9210" - SDHI IP on R7S9210 SoC "renesas,sdhi-r8a73a4" - SDHI IP on R8A73A4 SoC "renesas,sdhi-r8a7740" - SDHI IP on R8A7740 SoC "renesas,sdhi-r8a7743" - SDHI IP on R8A7743 SoC "renesas,sdhi-r8a7744" - SDHI IP on R8A7744 SoC "renesas,sdhi-r8a7745" - SDHI IP on R8A7745 SoC "renesas,sdhi-r8a774a1" - SDHI IP on R8A774A1 SoC + "renesas,sdhi-r8a774c0" - SDHI IP on R8A774C0 SoC "renesas,sdhi-r8a77470" - SDHI IP on R8A77470 SoC "renesas,sdhi-mmc-r8a77470" - SDHI/MMC IP on R8A77470 SoC "renesas,sdhi-r8a7778" - SDHI IP on R8A7778 SoC @@ -56,7 +58,7 @@ Required properties: "core" and "cd". If the controller only has 1 clock, naming is not required. Devices which have more than 1 clock are listed below: - 2: R7S72100 + 2: R7S72100, R7S9210 Optional properties: - pinctrl-names: should be "default", "state_uhs" diff --git a/Documentation/devicetree/bindings/net/broadcom-bluetooth.txt b/Documentation/devicetree/bindings/net/broadcom-bluetooth.txt index 4194ff7e6ee6..c26f4e11037c 100644 --- a/Documentation/devicetree/bindings/net/broadcom-bluetooth.txt +++ b/Documentation/devicetree/bindings/net/broadcom-bluetooth.txt @@ -10,6 +10,8 @@ device the slave device is attached to. Required properties: - compatible: should contain one of the following: + * "brcm,bcm20702a1" + * "brcm,bcm4330-bt" * "brcm,bcm43438-bt" Optional properties: @@ -18,8 +20,13 @@ Optional properties: - shutdown-gpios: GPIO specifier, used to enable the BT module - device-wakeup-gpios: GPIO specifier, used to wakeup the controller - host-wakeup-gpios: GPIO specifier, used to wakeup the host processor - - clocks: clock specifier if external clock provided to the controller - - clock-names: should be "extclk" + - clocks: 1 or 2 clocks as defined in clock-names below, in that order + - clock-names: names for clock inputs, matching the clocks given + - "extclk": deprecated, replaced by "txco" + - "txco": external reference clock (not a standalone crystal) + - "lpo": external low power 32.768 kHz clock + - vbat-supply: phandle to regulator supply for VBAT + - vddio-supply: phandle to regulator supply for VDDIO Example: diff --git a/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt b/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt index bfc0c433654f..bc77477c6878 100644 --- a/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt +++ b/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt @@ -24,6 +24,14 @@ Optional properties: if this property is present then controller is assumed to be big endian. +- fsl,stop-mode: register bits of stop mode control, the format is + <&gpr req_gpr req_bit ack_gpr ack_bit>. + gpr is the phandle to general purpose register node. + req_gpr is the gpr register offset of CAN stop request. + req_bit is the bit offset of CAN stop request. + ack_gpr is the gpr register offset of CAN stop acknowledge. + ack_bit is the bit offset of CAN stop acknowledge. + Example: can@1c000 { diff --git a/Documentation/devicetree/bindings/net/can/xilinx_can.txt b/Documentation/devicetree/bindings/net/can/xilinx_can.txt index 060e2d46bad9..100cc40b8510 100644 --- a/Documentation/devicetree/bindings/net/can/xilinx_can.txt +++ b/Documentation/devicetree/bindings/net/can/xilinx_can.txt @@ -6,6 +6,7 @@ Required properties: - "xlnx,zynq-can-1.0" for Zynq CAN controllers - "xlnx,axi-can-1.00.a" for Axi CAN controllers - "xlnx,canfd-1.0" for CAN FD controllers + - "xlnx,canfd-2.0" for CAN FD 2.0 controllers - reg : Physical base address and size of the controller registers map. - interrupts : Property with a value describing the interrupt diff --git a/Documentation/devicetree/bindings/net/cpsw.txt b/Documentation/devicetree/bindings/net/cpsw.txt index b3acebe08eb0..3264e1978d25 100644 --- a/Documentation/devicetree/bindings/net/cpsw.txt +++ b/Documentation/devicetree/bindings/net/cpsw.txt @@ -22,7 +22,8 @@ Required properties: - cpsw-phy-sel : Specifies the phandle to the CPSW phy mode selection device. See also cpsw-phy-sel.txt for it's binding. Note that in legacy cases cpsw-phy-sel may be - a child device instead of a phandle. + a child device instead of a phandle + (DEPRECATED, use phys property instead). Optional properties: - ti,hwmods : Must be "cpgmac0" @@ -44,6 +45,7 @@ Optional properties: Slave Properties: Required properties: - phy-mode : See ethernet.txt file in the same directory +- phys : phandle on phy-gmii-sel PHY (see phy/ti-phy-gmii-sel.txt) Optional properties: - dual_emac_res_vlan : Specifies VID to be used to segregate the ports @@ -85,12 +87,14 @@ Examples: phy-mode = "rgmii-txid"; /* Filled in by U-Boot */ mac-address = [ 00 00 00 00 00 00 ]; + phys = <&phy_gmii_sel 1 0>; }; cpsw_emac1: slave@1 { phy_id = <&davinci_mdio>, <1>; phy-mode = "rgmii-txid"; /* Filled in by U-Boot */ mac-address = [ 00 00 00 00 00 00 ]; + phys = <&phy_gmii_sel 2 0>; }; }; @@ -114,11 +118,13 @@ Examples: phy-mode = "rgmii-txid"; /* Filled in by U-Boot */ mac-address = [ 00 00 00 00 00 00 ]; + phys = <&phy_gmii_sel 1 0>; }; cpsw_emac1: slave@1 { phy_id = <&davinci_mdio>, <1>; phy-mode = "rgmii-txid"; /* Filled in by U-Boot */ mac-address = [ 00 00 00 00 00 00 ]; + phys = <&phy_gmii_sel 2 0>; }; }; diff --git a/Documentation/devicetree/bindings/net/dsa/ksz.txt b/Documentation/devicetree/bindings/net/dsa/ksz.txt index ac145b885e95..0f407fb371ce 100644 --- a/Documentation/devicetree/bindings/net/dsa/ksz.txt +++ b/Documentation/devicetree/bindings/net/dsa/ksz.txt @@ -8,6 +8,10 @@ Required properties: - "microchip,ksz9477" - "microchip,ksz9897" +Optional properties: + +- reset-gpios : Should be a gpio specifier for a reset line + See Documentation/devicetree/bindings/net/dsa/dsa.txt for a list of additional required and optional properties. diff --git a/Documentation/devicetree/bindings/net/dwmac-sun8i.txt b/Documentation/devicetree/bindings/net/dwmac-sun8i.txt index 5bb3a18cc38d..54c66d0611cb 100644 --- a/Documentation/devicetree/bindings/net/dwmac-sun8i.txt +++ b/Documentation/devicetree/bindings/net/dwmac-sun8i.txt @@ -10,6 +10,7 @@ Required properties: "allwinner,sun8i-r40-gmac" "allwinner,sun8i-v3s-emac" "allwinner,sun50i-a64-emac" + "allwinner,sun50i-h6-emac", "allwinner-sun50i-a64-emac" - reg: address and length of the register for the device. - interrupts: interrupt for the device - interrupt-names: must be "macirq" diff --git a/Documentation/devicetree/bindings/net/icplus-ip101ag.txt b/Documentation/devicetree/bindings/net/icplus-ip101ag.txt new file mode 100644 index 000000000000..a784592bbb15 --- /dev/null +++ b/Documentation/devicetree/bindings/net/icplus-ip101ag.txt @@ -0,0 +1,19 @@ +IC Plus Corp. IP101A / IP101G Ethernet PHYs + +There are different models of the IP101G Ethernet PHY: +- IP101GR (32-pin QFN package) +- IP101G (die only, no package) +- IP101GA (48-pin LQFP package) + +There are different models of the IP101A Ethernet PHY (which is the +predecessor of the IP101G): +- IP101A (48-pin LQFP package) +- IP101AH (48-pin LQFP package) + +Optional properties for the IP101GR (32-pin QFN package): + +- icplus,select-rx-error: + pin 21 ("RXER/INTR_32") will output the receive error status. + interrupts are not routed outside the PHY in this mode. +- icplus,select-interrupt: + pin 21 ("RXER/INTR_32") will output the interrupt signal. diff --git a/Documentation/devicetree/bindings/net/mediatek-dwmac.txt b/Documentation/devicetree/bindings/net/mediatek-dwmac.txt new file mode 100644 index 000000000000..8a08621a5b54 --- /dev/null +++ b/Documentation/devicetree/bindings/net/mediatek-dwmac.txt @@ -0,0 +1,78 @@ +MediaTek DWMAC glue layer controller + +This file documents platform glue layer for stmmac. +Please see stmmac.txt for the other unchanged properties. + +The device node has following properties. + +Required properties: +- compatible: Should be "mediatek,mt2712-gmac" for MT2712 SoC +- reg: Address and length of the register set for the device +- interrupts: Should contain the MAC interrupts +- interrupt-names: Should contain a list of interrupt names corresponding to + the interrupts in the interrupts property, if available. + Should be "macirq" for the main MAC IRQ +- clocks: Must contain a phandle for each entry in clock-names. +- clock-names: The name of the clock listed in the clocks property. These are + "axi", "apb", "mac_main", "ptp_ref" for MT2712 SoC +- mac-address: See ethernet.txt in the same directory +- phy-mode: See ethernet.txt in the same directory +- mediatek,pericfg: A phandle to the syscon node that control ethernet + interface and timing delay. + +Optional properties: +- mediatek,tx-delay-ps: TX clock delay macro value. Default is 0. + It should be defined for RGMII/MII interface. +- mediatek,rx-delay-ps: RX clock delay macro value. Default is 0. + It should be defined for RGMII/MII/RMII interface. +Both delay properties need to be a multiple of 170 for RGMII interface, +or will round down. Range 0~31*170. +Both delay properties need to be a multiple of 550 for MII/RMII interface, +or will round down. Range 0~31*550. + +- mediatek,rmii-rxc: boolean property, if present indicates that the RMII + reference clock, which is from external PHYs, is connected to RXC pin + on MT2712 SoC. + Otherwise, is connected to TXC pin. +- mediatek,txc-inverse: boolean property, if present indicates that + 1. tx clock will be inversed in MII/RGMII case, + 2. tx clock inside MAC will be inversed relative to reference clock + which is from external PHYs in RMII case, and it rarely happen. +- mediatek,rxc-inverse: boolean property, if present indicates that + 1. rx clock will be inversed in MII/RGMII case. + 2. reference clock will be inversed when arrived at MAC in RMII case. +- assigned-clocks: mac_main and ptp_ref clocks +- assigned-clock-parents: parent clocks of the assigned clocks + +Example: + eth: ethernet@1101c000 { + compatible = "mediatek,mt2712-gmac"; + reg = <0 0x1101c000 0 0x1300>; + interrupts = <GIC_SPI 237 IRQ_TYPE_LEVEL_LOW>; + interrupt-names = "macirq"; + phy-mode ="rgmii"; + mac-address = [00 55 7b b5 7d f7]; + clock-names = "axi", + "apb", + "mac_main", + "ptp_ref", + "ptp_top"; + clocks = <&pericfg CLK_PERI_GMAC>, + <&pericfg CLK_PERI_GMAC_PCLK>, + <&topckgen CLK_TOP_ETHER_125M_SEL>, + <&topckgen CLK_TOP_ETHER_50M_SEL>; + assigned-clocks = <&topckgen CLK_TOP_ETHER_125M_SEL>, + <&topckgen CLK_TOP_ETHER_50M_SEL>; + assigned-clock-parents = <&topckgen CLK_TOP_ETHERPLL_125M>, + <&topckgen CLK_TOP_APLL1_D3>; + mediatek,pericfg = <&pericfg>; + mediatek,tx-delay-ps = <1530>; + mediatek,rx-delay-ps = <1530>; + mediatek,rmii-rxc; + mediatek,txc-inverse; + mediatek,rxc-inverse; + snps,txpbl = <32>; + snps,rxpbl = <32>; + snps,reset-gpio = <&pio 87 GPIO_ACTIVE_LOW>; + snps,reset-active-low; + }; diff --git a/Documentation/devicetree/bindings/net/renesas,ravb.txt b/Documentation/devicetree/bindings/net/renesas,ravb.txt index 3530256a879c..7ad36213093e 100644 --- a/Documentation/devicetree/bindings/net/renesas,ravb.txt +++ b/Documentation/devicetree/bindings/net/renesas,ravb.txt @@ -18,6 +18,7 @@ Required properties: R-Car Gen2 and RZ/G1 devices. - "renesas,etheravb-r8a774a1" for the R8A774A1 SoC. + - "renesas,etheravb-r8a774c0" for the R8A774C0 SoC. - "renesas,etheravb-r8a7795" for the R8A7795 SoC. - "renesas,etheravb-r8a7796" for the R8A7796 SoC. - "renesas,etheravb-r8a77965" for the R8A77965 SoC. diff --git a/Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt b/Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt index 2196d1ab3c8c..ae661e65354e 100644 --- a/Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt +++ b/Documentation/devicetree/bindings/net/wireless/qcom,ath10k.txt @@ -21,10 +21,22 @@ can be provided per device. SNOC based devices (i.e. wcn3990) uses compatible string "qcom,wcn3990-wifi". -Optional properties: - reg: Address and length of the register set for the device. - reg-names: Must include the list of following reg names, "membase" +- interrupts: reference to the list of 17 interrupt numbers for "qcom,ipq4019-wifi" + compatible target. + reference to the list of 12 interrupt numbers for "qcom,wcn3990-wifi" + compatible target. + Must contain interrupt-names property per entry for + "qcom,ath10k", "qcom,ipq4019-wifi" compatible targets. + +- interrupt-names: Must include the entries for MSI interrupt + names ("msi0" to "msi15") and legacy interrupt + name ("legacy") for "qcom,ath10k", "qcom,ipq4019-wifi" + compatible targets. + +Optional properties: - resets: Must contain an entry for each entry in reset-names. See ../reset/reseti.txt for details. - reset-names: Must include the list of following reset names, @@ -37,12 +49,9 @@ Optional properties: - clocks: List of clock specifiers, must contain an entry for each required entry in clock-names. - clock-names: Should contain the clock names "wifi_wcss_cmd", "wifi_wcss_ref", - "wifi_wcss_rtc". -- interrupts: List of interrupt lines. Must contain an entry - for each entry in the interrupt-names property. -- interrupt-names: Must include the entries for MSI interrupt - names ("msi0" to "msi15") and legacy interrupt - name ("legacy"), + "wifi_wcss_rtc" for "qcom,ipq4019-wifi" compatible target and + "cxo_ref_clk_pin" for "qcom,wcn3990-wifi" + compatible target. - qcom,msi_addr: MSI interrupt address. - qcom,msi_base: Base value to add before writing MSI data into MSI address register. @@ -55,14 +64,25 @@ Optional properties: - qcom,ath10k-pre-calibration-data : pre calibration data as an array, the length can vary between hw versions. - <supply-name>-supply: handle to the regulator device tree node - optional "supply-name" is "vdd-0.8-cx-mx". + optional "supply-name" are "vdd-0.8-cx-mx", + "vdd-1.8-xo", "vdd-1.3-rfa" and "vdd-3.3-ch0". - memory-region: Usage: optional Value type: <phandle> Definition: reference to the reserved-memory for the msa region used by the wifi firmware running in Q6. +- iommus: + Usage: optional + Value type: <prop-encoded-array> + Definition: A list of phandle and IOMMU specifier pairs. +- ext-fem-name: + Usage: Optional + Value type: string + Definition: Name of external front end module used. Some valid FEM names + for example: "microsemi-lx5586", "sky85703-11" + and "sky85803" etc. -Example (to supply the calibration data alone): +Example (to supply PCI based wifi block details): In this example, the node is defined as child node of the PCI controller. @@ -74,10 +94,10 @@ pci { #address-cells = <3>; device_type = "pci"; - ath10k@0,0 { + wifi@0,0 { reg = <0 0 0 0 0>; - device_type = "pci"; qcom,ath10k-calibration-data = [ 01 02 03 ... ]; + ext-fem-name = "microsemi-lx5586"; }; }; }; @@ -138,21 +158,25 @@ wifi@18000000 { compatible = "qcom,wcn3990-wifi"; reg = <0x18800000 0x800000>; reg-names = "membase"; - clocks = <&clock_gcc clk_aggre2_noc_clk>; - clock-names = "smmu_aggre2_noc_clk" + clocks = <&clock_gcc clk_rf_clk2_pin>; + clock-names = "cxo_ref_clk_pin"; interrupts = - <0 130 0 /* CE0 */ >, - <0 131 0 /* CE1 */ >, - <0 132 0 /* CE2 */ >, - <0 133 0 /* CE3 */ >, - <0 134 0 /* CE4 */ >, - <0 135 0 /* CE5 */ >, - <0 136 0 /* CE6 */ >, - <0 137 0 /* CE7 */ >, - <0 138 0 /* CE8 */ >, - <0 139 0 /* CE9 */ >, - <0 140 0 /* CE10 */ >, - <0 141 0 /* CE11 */ >; + <GIC_SPI 414 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 415 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 416 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 417 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 418 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 419 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 420 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 421 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 422 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 423 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 424 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 425 IRQ_TYPE_LEVEL_HIGH>; vdd-0.8-cx-mx-supply = <&pm8998_l5>; + vdd-1.8-xo-supply = <&vreg_l7a_1p8>; + vdd-1.3-rfa-supply = <&vreg_l17a_1p3>; + vdd-3.3-ch0-supply = <&vreg_l25a_3p3>; memory-region = <&wifi_msa_mem>; + iommus = <&apps_smmu 0x0040 0x1>; }; diff --git a/Documentation/devicetree/bindings/nvmem/amlogic-efuse.txt b/Documentation/devicetree/bindings/nvmem/amlogic-efuse.txt index e3298e18de26..2e0723ab3384 100644 --- a/Documentation/devicetree/bindings/nvmem/amlogic-efuse.txt +++ b/Documentation/devicetree/bindings/nvmem/amlogic-efuse.txt @@ -2,6 +2,8 @@ Required properties: - compatible: should be "amlogic,meson-gxbb-efuse" +- clocks: phandle to the efuse peripheral clock provided by the + clock controller. = Data cells = Are child nodes of eFuse, bindings of which as described in @@ -11,6 +13,7 @@ Example: efuse: efuse { compatible = "amlogic,meson-gxbb-efuse"; + clocks = <&clkc CLKID_EFUSE>; #address-cells = <1>; #size-cells = <1>; diff --git a/Documentation/devicetree/bindings/pci/host-generic-pci.txt b/Documentation/devicetree/bindings/pci/host-generic-pci.txt index 3f1d3fca62bb..614b594f4e72 100644 --- a/Documentation/devicetree/bindings/pci/host-generic-pci.txt +++ b/Documentation/devicetree/bindings/pci/host-generic-pci.txt @@ -56,7 +56,7 @@ For CAM, this 24-bit offset is: cfg_offset(bus, device, function, register) = bus << 16 | device << 11 | function << 8 | register -Whilst ECAM extends this by 4 bits to accommodate 4k of function space: +While ECAM extends this by 4 bits to accommodate 4k of function space: cfg_offset(bus, device, function, register) = bus << 20 | device << 15 | function << 12 | register diff --git a/Documentation/devicetree/bindings/pci/layerscape-pci.txt b/Documentation/devicetree/bindings/pci/layerscape-pci.txt index 66df1e81e0b8..9b2b8d66d1f4 100644 --- a/Documentation/devicetree/bindings/pci/layerscape-pci.txt +++ b/Documentation/devicetree/bindings/pci/layerscape-pci.txt @@ -13,11 +13,12 @@ information. Required properties: - compatible: should contain the platform identifier such as: - "fsl,ls1021a-pcie", "snps,dw-pcie" - "fsl,ls2080a-pcie", "fsl,ls2085a-pcie", "snps,dw-pcie" + "fsl,ls1021a-pcie" + "fsl,ls2080a-pcie", "fsl,ls2085a-pcie" "fsl,ls2088a-pcie" "fsl,ls1088a-pcie" "fsl,ls1046a-pcie" + "fsl,ls1043a-pcie" "fsl,ls1012a-pcie" - reg: base addresses and lengths of the PCIe controller register blocks. - interrupts: A list of interrupt outputs of the controller. Must contain an @@ -35,7 +36,7 @@ Required properties: Example: pcie@3400000 { - compatible = "fsl,ls1021a-pcie", "snps,dw-pcie"; + compatible = "fsl,ls1021a-pcie"; reg = <0x00 0x03400000 0x0 0x00010000 /* controller registers */ 0x40 0x00000000 0x0 0x00002000>; /* configuration space */ reg-names = "regs", "config"; diff --git a/Documentation/devicetree/bindings/perf/nds32v3-pmu.txt b/Documentation/devicetree/bindings/perf/nds32v3-pmu.txt new file mode 100644 index 000000000000..1bd15785b4ae --- /dev/null +++ b/Documentation/devicetree/bindings/perf/nds32v3-pmu.txt @@ -0,0 +1,17 @@ +* NDS32 Performance Monitor Units + +NDS32 core have a PMU for counting cpu and cache events like cache misses. +The NDS32 PMU representation in the device tree should be done as under: + +Required properties: + +- compatible : + "andestech,nds32v3-pmu" + +- interrupts : The interrupt number for NDS32 PMU is 13. + +Example: +pmu{ + compatible = "andestech,nds32v3-pmu"; + interrupts = <13>; +} diff --git a/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.txt b/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.txt new file mode 100644 index 000000000000..a22e853d710c --- /dev/null +++ b/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.txt @@ -0,0 +1,17 @@ +* Freescale i.MX8MQ USB3 PHY binding + +Required properties: +- compatible: Should be "fsl,imx8mq-usb-phy" +- #phys-cells: must be 0 (see phy-bindings.txt in this directory) +- reg: The base address and length of the registers +- clocks: phandles to the clocks for each clock listed in clock-names +- clock-names: must contain "phy" + +Example: + usb3_phy0: phy@381f0040 { + compatible = "fsl,imx8mq-usb-phy"; + reg = <0x381f0040 0x40>; + clocks = <&clk IMX8MQ_CLK_USB1_PHY_ROOT>; + clock-names = "phy"; + #phy-cells = <0>; + }; diff --git a/Documentation/devicetree/bindings/phy/phy-cadence-sierra.txt b/Documentation/devicetree/bindings/phy/phy-cadence-sierra.txt new file mode 100644 index 000000000000..6e1b47bfce43 --- /dev/null +++ b/Documentation/devicetree/bindings/phy/phy-cadence-sierra.txt @@ -0,0 +1,67 @@ +Cadence Sierra PHY +----------------------- + +Required properties: +- compatible: cdns,sierra-phy-t0 +- clocks: Must contain an entry in clock-names. + See ../clocks/clock-bindings.txt for details. +- clock-names: Must be "phy_clk" +- resets: Must contain an entry for each in reset-names. + See ../reset/reset.txt for details. +- reset-names: Must include "sierra_reset" and "sierra_apb". + "sierra_reset" must control the reset line to the PHY. + "sierra_apb" must control the reset line to the APB PHY + interface. +- reg: register range for the PHY. +- #address-cells: Must be 1 +- #size-cells: Must be 0 + +Optional properties: +- cdns,autoconf: A boolean property whose presence indicates that the + PHY registers will be configured by hardware. If not + present, all sub-node optional properties must be + provided. + +Sub-nodes: + Each group of PHY lanes with a single master lane should be represented as + a sub-node. Note that the actual configuration of each lane is determined by + hardware strapping, and must match the configuration specified here. + +Sub-node required properties: +- #phy-cells: Generic PHY binding; must be 0. +- reg: The master lane number. This is the lowest numbered lane + in the lane group. +- resets: Must contain one entry which controls the reset line for the + master lane of the sub-node. + See ../reset/reset.txt for details. + +Sub-node optional properties: +- cdns,num-lanes: Number of lanes in this group. From 1 to 4. The + group is made up of consecutive lanes. +- cdns,phy-type: Can be PHY_TYPE_PCIE or PHY_TYPE_USB3, depending on + configuration of lanes. + +Example: + pcie_phy4: pcie-phy@fd240000 { + compatible = "cdns,sierra-phy-t0"; + reg = <0x0 0xfd240000 0x0 0x40000>; + resets = <&phyrst 0>, <&phyrst 1>; + reset-names = "sierra_reset", "sierra_apb"; + clocks = <&phyclock>; + clock-names = "phy_clk"; + #address-cells = <1>; + #size-cells = <0>; + pcie0_phy0: pcie-phy@0 { + reg = <0>; + resets = <&phyrst 2>; + cdns,num-lanes = <2>; + #phy-cells = <0>; + cdns,phy-type = <PHY_TYPE_PCIE>; + }; + pcie0_phy1: pcie-phy@2 { + reg = <2>; + resets = <&phyrst 4>; + cdns,num-lanes = <1>; + #phy-cells = <0>; + cdns,phy-type = <PHY_TYPE_PCIE>; + }; diff --git a/Documentation/devicetree/bindings/phy/qcom-qmp-phy.txt b/Documentation/devicetree/bindings/phy/qcom-qmp-phy.txt index fbc198d5dd39..41a1074228ba 100644 --- a/Documentation/devicetree/bindings/phy/qcom-qmp-phy.txt +++ b/Documentation/devicetree/bindings/phy/qcom-qmp-phy.txt @@ -25,10 +25,6 @@ Required properties: - For all others: - The reg-names property shouldn't be defined. - - #clock-cells: must be 1 - - Phy pll outputs a bunch of clocks for Tx, Rx and Pipe - interface (for pipe based PHYs). These clock are then gate-controlled - by gcc. - #address-cells: must be 1 - #size-cells: must be 1 - ranges: must be present @@ -82,27 +78,33 @@ Required nodes: - Each device node of QMP phy is required to have as many child nodes as the number of lanes the PHY has. -Required properties for child node: +Required properties for child nodes of PCIe PHYs (one child per lane): - reg: list of offset and length pairs of register sets for PHY blocks - - - index 0: tx - - index 1: rx - - index 2: pcs - - index 3: pcs_misc (optional) + tx, rx, pcs, and pcs_misc (optional). + - #phy-cells: must be 0 +Required properties for a single "lanes" child node of non-PCIe PHYs: + - reg: list of offset and length pairs of register sets for PHY blocks + For 1-lane devices: + tx, rx, pcs, and (optionally) pcs_misc + For 2-lane devices: + tx0, rx0, pcs, tx1, rx1, and (optionally) pcs_misc - #phy-cells: must be 0 -Required properties child node of pcie and usb3 qmp phys: +Required properties for child node of PCIe and USB3 qmp phys: - clocks: a list of phandles and clock-specifier pairs, one for each entry in clock-names. - clock-names: Must contain following: "pipe<lane-number>" for pipe clock specific to each lane. - clock-output-names: Name of the PHY clock that will be the parent for the above pipe clock. - For "qcom,ipq8074-qmp-pcie-phy": - "pcie20_phy0_pipe_clk" Pipe Clock parent (or) "pcie20_phy1_pipe_clk" + - #clock-cells: must be 0 + - Phy pll outputs pipe clocks for pipe based PHYs. These clocks are then + gate-controlled by the gcc. Required properties for child node of PHYs with lane reset, AKA: "qcom,msm8996-qmp-pcie-phy" @@ -115,7 +117,6 @@ Example: phy@34000 { compatible = "qcom,msm8996-qmp-pcie-phy"; reg = <0x34000 0x488>; - #clock-cells = <1>; #address-cells = <1>; #size-cells = <1>; ranges; @@ -137,6 +138,7 @@ Example: reg = <0x35000 0x130>, <0x35200 0x200>, <0x35400 0x1dc>; + #clock-cells = <0>; #phy-cells = <0>; clocks = <&gcc GCC_PCIE_0_PIPE_CLK>; @@ -150,3 +152,54 @@ Example: ... ... }; + + phy@88eb000 { + compatible = "qcom,sdm845-qmp-usb3-uni-phy"; + reg = <0x88eb000 0x18c>; + #address-cells = <1>; + #size-cells = <1>; + ranges; + + clocks = <&gcc GCC_USB3_SEC_PHY_AUX_CLK>, + <&gcc GCC_USB_PHY_CFG_AHB2PHY_CLK>, + <&gcc GCC_USB3_SEC_CLKREF_CLK>, + <&gcc GCC_USB3_SEC_PHY_COM_AUX_CLK>; + clock-names = "aux", "cfg_ahb", "ref", "com_aux"; + + resets = <&gcc GCC_USB3PHY_PHY_SEC_BCR>, + <&gcc GCC_USB3_PHY_SEC_BCR>; + reset-names = "phy", "common"; + + lane@88eb200 { + reg = <0x88eb200 0x128>, + <0x88eb400 0x1fc>, + <0x88eb800 0x218>, + <0x88eb600 0x70>; + #clock-cells = <0>; + #phy-cells = <0>; + clocks = <&gcc GCC_USB3_SEC_PHY_PIPE_CLK>; + clock-names = "pipe0"; + clock-output-names = "usb3_uni_phy_pipe_clk_src"; + }; + }; + + phy@1d87000 { + compatible = "qcom,sdm845-qmp-ufs-phy"; + reg = <0x1d87000 0x18c>; + #address-cells = <1>; + #size-cells = <1>; + ranges; + clock-names = "ref", + "ref_aux"; + clocks = <&gcc GCC_UFS_MEM_CLKREF_CLK>, + <&gcc GCC_UFS_PHY_PHY_AUX_CLK>; + + lanes@1d87400 { + reg = <0x1d87400 0x108>, + <0x1d87600 0x1e0>, + <0x1d87c00 0x1dc>, + <0x1d87800 0x108>, + <0x1d87a00 0x1e0>; + #phy-cells = <0>; + }; + }; diff --git a/Documentation/devicetree/bindings/phy/sun4i-usb-phy.txt b/Documentation/devicetree/bindings/phy/sun4i-usb-phy.txt index 07ca4ec4a745..f2e120af17f0 100644 --- a/Documentation/devicetree/bindings/phy/sun4i-usb-phy.txt +++ b/Documentation/devicetree/bindings/phy/sun4i-usb-phy.txt @@ -14,13 +14,14 @@ Required properties: * allwinner,sun8i-r40-usb-phy * allwinner,sun8i-v3s-usb-phy * allwinner,sun50i-a64-usb-phy + * allwinner,sun50i-h6-usb-phy - reg : a list of offset + length pairs - reg-names : * "phy_ctrl" - * "pmu0" for H3, V3s and A64 + * "pmu0" for H3, V3s, A64 or H6 * "pmu1" * "pmu2" for sun4i, sun6i, sun7i, sun8i-a83t or sun8i-h3 - * "pmu3" for sun8i-h3 + * "pmu3" for sun8i-h3 or sun50i-h6 - #phy-cells : from the generic phy bindings, must be 1 - clocks : phandle + clock specifier for the phy clocks - clock-names : @@ -29,12 +30,13 @@ Required properties: * "usb0_phy", "usb1_phy" for sun8i * "usb0_phy", "usb1_phy", "usb2_phy" and "usb2_hsic_12M" for sun8i-a83t * "usb0_phy", "usb1_phy", "usb2_phy" and "usb3_phy" for sun8i-h3 + * "usb0_phy" and "usb3_phy" for sun50i-h6 - resets : a list of phandle + reset specifier pairs - reset-names : * "usb0_reset" * "usb1_reset" * "usb2_reset" for sun4i, sun6i, sun7i, sun8i-a83t or sun8i-h3 - * "usb3_reset" for sun8i-h3 + * "usb3_reset" for sun8i-h3 and sun50i-h6 Optional properties: - usb0_id_det-gpios : gpio phandle for reading the otg id pin value diff --git a/Documentation/devicetree/bindings/phy/ti-phy-gmii-sel.txt b/Documentation/devicetree/bindings/phy/ti-phy-gmii-sel.txt new file mode 100644 index 000000000000..50ce9ae0f7a5 --- /dev/null +++ b/Documentation/devicetree/bindings/phy/ti-phy-gmii-sel.txt @@ -0,0 +1,68 @@ +CPSW Port's Interface Mode Selection PHY Tree Bindings +----------------------------------------------- + +TI am335x/am437x/dra7(am5)/dm814x CPSW3G Ethernet Subsystem supports +two 10/100/1000 Ethernet ports with selectable G/MII, RMII, and RGMII interfaces. +The interface mode is selected by configuring the MII mode selection register(s) +(GMII_SEL) in the System Control Module chapter (SCM). GMII_SEL register(s) and +bit fields placement in SCM are different between SoCs while fields meaning +is the same. + +--------------+ + +-------------------------------+ |SCM | + | CPSW | | +---------+ | + | +--------------------------------+gmii_sel | | + | | | | +---------+ | + | +----v---+ +--------+ | +--------------+ + | |Port 1..<--+-->GMII/MII<-------> + | | | | | | | + | +--------+ | +--------+ | + | | | + | | +--------+ | + | | | RMII <-------> + | +--> | | + | | +--------+ | + | | | + | | +--------+ | + | | | RGMII <-------> + | +--> | | + | +--------+ | + +-------------------------------+ + +CPSW Port's Interface Mode Selection PHY describes MII interface mode between +CPSW Port and Ethernet PHY which depends on Eth PHY and board configuration. + +CPSW Port's Interface Mode Selection PHY device should defined as child device +of SCM node (scm_conf) and can be attached to each CPSW port node using standard +PHY bindings (See phy/phy-bindings.txt). + +Required properties: +- compatible : Should be "ti,am3352-phy-gmii-sel" for am335x platform + "ti,dra7xx-phy-gmii-sel" for dra7xx/am57xx platform + "ti,am43xx-phy-gmii-sel" for am43xx platform + "ti,dm814-phy-gmii-sel" for dm814x platform +- reg : Address and length of the register set for the device +- #phy-cells : must be 2. + cell 1 - CPSW port number (starting from 1) + cell 2 - RMII refclk mode + +Examples: + phy_gmii_sel: phy-gmii-sel { + compatible = "ti,am3352-phy-gmii-sel"; + reg = <0x650 0x4>; + #phy-cells = <2>; + }; + + mac: ethernet@4a100000 { + compatible = "ti,am335x-cpsw","ti,cpsw"; + ... + + cpsw_emac0: slave@4a100200 { + ... + phys = <&phy_gmii_sel 1 1>; + }; + + cpsw_emac1: slave@4a100300 { + ... + phys = <&phy_gmii_sel 2 1>; + }; + }; diff --git a/Documentation/devicetree/bindings/pinctrl/actions,s700-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/actions,s700-pinctrl.txt new file mode 100644 index 000000000000..d13ff82f8518 --- /dev/null +++ b/Documentation/devicetree/bindings/pinctrl/actions,s700-pinctrl.txt @@ -0,0 +1,170 @@ +Actions Semi S700 Pin Controller + +This binding describes the pin controller found in the S700 SoC. + +Required Properties: + +- compatible: Should be "actions,s700-pinctrl" +- reg: Should contain the register base address and size of + the pin controller. +- clocks: phandle of the clock feeding the pin controller +- gpio-controller: Marks the device node as a GPIO controller. +- gpio-ranges: Specifies the mapping between gpio controller and + pin-controller pins. +- #gpio-cells: Should be two. The first cell is the gpio pin number + and the second cell is used for optional parameters. +- interrupt-controller: Marks the device node as an interrupt controller. +- #interrupt-cells: Specifies the number of cells needed to encode an + interrupt. Shall be set to 2. The first cell + defines the interrupt number, the second encodes + the trigger flags described in + bindings/interrupt-controller/interrupts.txt +- interrupts: The interrupt outputs from the controller. There is one GPIO + interrupt per GPIO bank. The number of interrupts listed depends + on the number of GPIO banks on the SoC. The interrupts must be + ordered by bank, starting with bank 0. + +Please refer to pinctrl-bindings.txt in this directory for details of the +common pinctrl bindings used by client devices, including the meaning of the +phrase "pin configuration node". + +The pin configuration nodes act as a container for an arbitrary number of +subnodes. Each of these subnodes represents some desired configuration for a +pin, a group, or a list of pins or groups. This configuration can include the +mux function to select on those group(s), and various pin configuration +parameters, such as pull-up, drive strength, etc. + +PIN CONFIGURATION NODES: + +The name of each subnode is not important; all subnodes should be enumerated +and processed purely based on their content. + +Each subnode only affects those parameters that are explicitly listed. In +other words, a subnode that lists a mux function but no pin configuration +parameters implies no information about any pin configuration parameters. +Similarly, a pin subnode that describes a pullup parameter implies no +information about e.g. the mux function. + +Pinmux functions are available only for the pin groups while pinconf +parameters are available for both pin groups and individual pins. + +The following generic properties as defined in pinctrl-bindings.txt are valid +to specify in a pin configuration subnode: + +Required Properties: + +- pins: An array of strings, each string containing the name of a pin. + These pins are used for selecting the pull control and schmitt + trigger parameters. The following are the list of pins + available: + + eth_txd0, eth_txd1, eth_txd2, eth_txd3, eth_txen, eth_rxer, + eth_crs_dv, eth_rxd1, eth_rxd0, eth_rxd2, eth_rxd3, eth_ref_clk, + eth_mdc, eth_mdio, sirq0, sirq1, sirq2, i2s_d0, i2s_bclk0, + i2s_lrclk0, i2s_mclk0, i2s_d1, i2s_bclk1, i2s_lrclk1, i2s_mclk1, + pcm1_in, pcm1_clk, pcm1_sync, pcm1_out, ks_in0, ks_in1, ks_in2, + ks_in3, ks_out0, ks_out1, ks_out2, lvds_oep, lvds_oen, lvds_odp, + lvds_odn, lvds_ocp, lvds_ocn, lvds_obp, lvds_obn, lvds_oap, + lvds_oan, lvds_eep, lvds_een, lvds_edp, lvds_edn, lvds_ecp, + lvds_ecn, lvds_ebp, lvds_ebn, lvds_eap, lvds_ean, lcd0_d18, + lcd0_d2, dsi_dp3, dsi_dn3, dsi_dp1, dsi_dn1, dsi_cp, dsi_cn, + dsi_dp0, dsi_dn0, dsi_dp2, dsi_dn2, sd0_d0, sd0_d1, sd0_d2, + sd0_d3, sd1_d0, sd1_d1, sd1_d2, sd1_d3, sd0_cmd, sd0_clk, + sd1_cmd, sd1_clk, spi0_ss, spi0_miso, uart0_rx, uart0_tx, + uart2_rx, uart2_tx, uart2_rtsb, uart2_ctsb, uart3_rx, uart3_tx, + uart3_rtsb, uart3_ctsb, i2c0_sclk, i2c0_sdata, i2c1_sclk, + i2c1_sdata, i2c2_sdata, csi_dn0, csi_dp0, csi_dn1, csi_dp1, + csi_cn, csi_cp, csi_dn2, csi_dp2, csi_dn3, csi_dp3, + sensor0_pclk, sensor0_ckout, dnand_d0, dnand_d1, dnand_d2, + dnand_d3, dnand_d4, dnand_d5, dnand_d6, dnand_d7, dnand_wrb, + dnand_rdb, dnand_rdbn, dnand_dqs, dnand_dqsn, dnand_rb0, + dnand_ale, dnand_cle, dnand_ceb0, dnand_ceb1, dnand_ceb2, + dnand_ceb3, porb, clko_25m, bsel, pkg0, pkg1, pkg2, pkg3 + +- groups: An array of strings, each string containing the name of a pin + group. These pin groups are used for selecting the pinmux + functions. + rgmii_txd23_mfp, rgmii_rxd2_mfp, rgmii_rxd3_mfp, lcd0_d18_mfp, + rgmii_txd01_mfp, rgmii_txd0_mfp, rgmii_txd1_mfp, rgmii_txen_mfp, + rgmii_rxen_mfp, rgmii_rxd1_mfp, rgmii_rxd0_mfp, rgmii_ref_clk_mfp, + i2s_d0_mfp, i2s_pcm1_mfp, i2s0_pcm0_mfp, i2s1_pcm0_mfp, + i2s_d1_mfp, ks_in2_mfp, ks_in1_mfp, ks_in0_mfp, ks_in3_mfp, + ks_out0_mfp, ks_out1_mfp, ks_out2_mfp, lvds_o_pn_mfp, dsi_dn0_mfp, + dsi_dp2_mfp, lcd0_d2_mfp, dsi_dp3_mfp, dsi_dn3_mfp, dsi_dp0_mfp, + lvds_ee_pn_mfp, uart2_rx_tx_mfp, spi0_i2c_pcm_mfp, dsi_dnp1_cp_d2_mfp, + dsi_dnp1_cp_d17_mfp, lvds_e_pn_mfp, dsi_dn2_mfp, uart2_rtsb_mfp, + uart2_ctsb_mfp, uart3_rtsb_mfp, uart3_ctsb_mfp, sd0_d0_mfp, sd0_d1_mfp, + sd0_d2_d3_mfp, sd1_d0_d3_mfp, sd0_cmd_mfp, sd0_clk_mfp, sd1_cmd_mfp, + uart0_rx_mfp, clko_25m_mfp, csi_cn_cp_mfp, sens0_ckout_mfp, uart0_tx_mfp, + i2c0_mfp, csi_dn_dp_mfp, sen0_pclk_mfp, pcm1_in_mfp, pcm1_clk_mfp, + pcm1_sync_mfp, pcm1_out_mfp, dnand_data_wr_mfp, dnand_acle_ce0_mfp, + nand_ceb2_mfp, nand_ceb3_mfp + + These pin groups are used for selecting the drive strength + parameters. + + sirq_drv, rgmii_txd23_drv, rgmii_rxd23_drv, rgmii_txd01_txen_drv, + rgmii_rxer_drv, rgmii_crs_drv, rgmii_rxd10_drv, rgmii_ref_clk_drv, + smi_mdc_mdio_drv, i2s_d0_drv, i2s_bclk0_drv, i2s3_drv, i2s13_drv, + pcm1_drv, ks_in_drv, ks_out_drv, lvds_all_drv, lcd_d18_d2_drv, + dsi_all_drv, sd0_d0_d3_drv, sd0_cmd_drv, sd0_clk_drv, spi0_all_drv, + uart0_rx_drv, uart0_tx_drv, uart2_all_drv, i2c0_all_drv, i2c12_all_drv, + sens0_pclk_drv, sens0_ckout_drv, uart3_all_drv + +- function: An array of strings, each string containing the name of the + pinmux functions. These functions can only be selected by + the corresponding pin groups. The following are the list of + pinmux functions available: + + nor, eth_rgmii, eth_sgmii, spi0, spi1, spi2, spi3, seNs0, sens1, + uart0, uart1, uart2, uart3, uart4, uart5, uart6, i2s0, i2s1, + pcm1, pcm0, ks, jtag, pwm0, pwm1, pwm2, pwm3, pwm4, pwm5, p0, + sd0, sd1, sd2, i2c0, i2c1, i2c2, i2c3, dsi, lvds, usb30, + clko_25m, mipi_csi, nand, spdif, sirq0, sirq1, sirq2, bt, lcd0 + +Optional Properties: + +- bias-pull-down: No arguments. The specified pins should be configured as + pull down. +- bias-pull-up: No arguments. The specified pins should be configured as + pull up. +- input-schmitt-enable: No arguments: Enable schmitt trigger for the specified + pins +- input-schmitt-disable: No arguments: Disable schmitt trigger for the specified + pins +- drive-strength: Integer. Selects the drive strength for the specified + pins in mA. + Valid values are: + <2> + <4> + <8> + <12> + +Example: + + pinctrl: pinctrl@e01b0000 { + compatible = "actions,s700-pinctrl"; + reg = <0x0 0xe01b0000 0x0 0x1000>; + clocks = <&cmu CLK_GPIO>; + gpio-controller; + gpio-ranges = <&pinctrl 0 0 136>; + #gpio-cells = <2>; + interrupt-controller; + #interrupt-cells = <2>; + interrupts = <GIC_SPI 36 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 37 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 38 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 39 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SPI 40 IRQ_TYPE_LEVEL_HIGH>; + + uart3-default: uart3-default { + pinmux { + groups = "uart3_rtsb_mfp", "uart3_ctsb_mfp"; + function = "uart3"; + }; + pinconf { + groups = "uart3_all_drv"; + drive-strength = <2>; + }; + }; + }; diff --git a/Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt index 258a4648ab81..cf96b7c20e4d 100644 --- a/Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt +++ b/Documentation/devicetree/bindings/pinctrl/allwinner,sunxi-pinctrl.txt @@ -29,6 +29,7 @@ Required properties: "allwinner,sun50i-h5-pinctrl" "allwinner,sun50i-h6-pinctrl" "allwinner,sun50i-h6-r-pinctrl" + "allwinner,suniv-f1c100s-pinctrl" "nextthing,gr8-pinctrl" - reg: Should contain the register physical address and length for the @@ -43,6 +44,19 @@ Note: For backward compatibility reasons, the hosc and losc clocks are only required if you need to use the optional input-debounce property. Any new device tree should set them. +Each pin bank, depending on the SoC, can have an associated regulator: + +- vcc-pa-supply: for the A10, A20, A31, A31s, A80 and R40 SoCs +- vcc-pb-supply: for the A31, A31s, A80 and V3s SoCs +- vcc-pc-supply: for the A10, A20, A31, A31s, A64, A80, H5, R40 and V3s SoCs +- vcc-pd-supply: for the A23, A31, A31s, A64, A80, A83t, H3, H5 and R40 SoCs +- vcc-pe-supply: for the A10, A20, A31, A31s, A64, A80, R40 and V3s SoCs +- vcc-pf-supply: for the A10, A20, A31, A31s, A80, R40 and V3s SoCs +- vcc-pg-supply: for the A10, A20, A31, A31s, A64, A80, H3, H5, R40 and V3s SoCs +- vcc-ph-supply: for the A31, A31s and A80 SoCs +- vcc-pl-supply: for the r-pinctrl of the A64, A80 and A83t SoCs +- vcc-pm-supply: for the r-pinctrl of the A31, A31s and A80 SoCs + Optional properties: - input-debounce: Array of debouncing periods in microseconds. One period per irq bank found in the controller. 0 if no setup required. diff --git a/Documentation/devicetree/bindings/pinctrl/brcm,bcm4708-pinmux.txt b/Documentation/devicetree/bindings/pinctrl/brcm,bcm4708-pinmux.txt index 4fa9539070cb..8ab2d468dbdb 100644 --- a/Documentation/devicetree/bindings/pinctrl/brcm,bcm4708-pinmux.txt +++ b/Documentation/devicetree/bindings/pinctrl/brcm,bcm4708-pinmux.txt @@ -7,13 +7,15 @@ configure controller correctly. A list of pins varies across chipsets so few bindings are available. +Node of the pinmux must be nested in the CRU (Central Resource Unit) "syscon" +noce. + Required properties: - compatible: must be one of: "brcm,bcm4708-pinmux" "brcm,bcm4709-pinmux" "brcm,bcm53012-pinmux" -- reg: iomem address range of CRU (Central Resource Unit) pin registers -- reg-names: "cru_gpio_control" - the only needed & supported reg right now +- offset: offset of pin registers in the CRU block Functions and their groups available for all chipsets: - "spi": "spi_grp" @@ -37,16 +39,12 @@ Example: #size-cells = <1>; cru@100 { - compatible = "simple-bus"; + compatible = "syscon", "simple-mfd"; reg = <0x100 0x1a4>; - ranges; - #address-cells = <1>; - #size-cells = <1>; - pin-controller@1c0 { + pinctrl { compatible = "brcm,bcm4708-pinmux"; - reg = <0x1c0 0x24>; - reg-names = "cru_gpio_control"; + offset = <0xc0>; spi-pins { function = "spi"; diff --git a/Documentation/devicetree/bindings/pinctrl/fsl,imx7ulp-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/fsl,imx7ulp-pinctrl.txt index 44ad670ae11e..bfa3703a7446 100644 --- a/Documentation/devicetree/bindings/pinctrl/fsl,imx7ulp-pinctrl.txt +++ b/Documentation/devicetree/bindings/pinctrl/fsl,imx7ulp-pinctrl.txt @@ -7,55 +7,47 @@ Note: This binding doc is only for the IOMUXC1 support in A7 Domain and it only supports generic pin config. -Please also refer pinctrl-bindings.txt in this directory for generic pinctrl -binding. - -=== Pin Controller Node === +Please refer to fsl,imx-pinctrl.txt in this directory for common binding +part and usage. Required properties: -- compatible: "fsl,imx7ulp-iomuxc1" -- reg: Should contain the base physical address and size of the iomuxc - registers. - -=== Pin Configuration Node === -- pinmux: One integers array, represents a group of pins mux setting. - The format is pinmux = <PIN_FUNC_ID>, PIN_FUNC_ID is a pin working on - a specific function. - - NOTE: i.MX7ULP PIN_FUNC_ID consists of 4 integers as it shares one mux - and config register as follows: - <mux_conf_reg input_reg mux_mode input_val> - - Refer to imx7ulp-pinfunc.h in in device tree source folder for all - available imx7ulp PIN_FUNC_ID. - -Optional Properties: -- drive-strength Integer. Controls Drive Strength - 0: Standard - 1: Hi Driver -- drive-push-pull Bool. Enable Pin Push-pull -- drive-open-drain Bool. Enable Pin Open-drian -- slew-rate: Integer. Controls Slew Rate - 0: Standard - 1: Slow -- bias-disable: Bool. Pull disabled -- bias-pull-down: Bool. Pull down on pin -- bias-pull-up: Bool. Pull up on pin +- compatible: "fsl,imx7ulp-iomuxc1". +- fsl,pins: Each entry consists of 5 integers which represents the mux + and config setting for one pin. The first 4 integers + <mux_conf_reg input_reg mux_mode input_val> are specified + using a PIN_FUNC_ID macro, which can be found in + imx7ulp-pinfunc.h in the device tree source folder. + The last integer CONFIG is the pad setting value like + pull-up on this pin. + + Please refer to i.MX7ULP Reference Manual for detailed + CONFIG settings. + +CONFIG bits definition: +PAD_CTL_OBE (1 << 17) +PAD_CTL_IBE (1 << 16) +PAD_CTL_LK (1 << 16) +PAD_CTL_DSE_HI (1 << 6) +PAD_CTL_DSE_STD (0 << 6) +PAD_CTL_ODE (1 << 5) +PAD_CTL_PUSH_PULL (0 << 5) +PAD_CTL_SRE_SLOW (1 << 2) +PAD_CTL_SRE_STD (0 << 2) +PAD_CTL_PE (1 << 0) Examples: #include "imx7ulp-pinfunc.h" /* Pin Controller Node */ -iomuxc1: iomuxc@40ac0000 { +iomuxc1: pinctrl@40ac0000 { compatible = "fsl,imx7ulp-iomuxc1"; reg = <0x40ac0000 0x1000>; /* Pin Configuration Node */ pinctrl_lpuart4: lpuart4grp { - pinmux = < - IMX7ULP_PAD_PTC3__LPUART4_RX - IMX7ULP_PAD_PTC2__LPUART4_TX + fsl,pins = < + IMX7ULP_PAD_PTC3__LPUART4_RX 0x1 + IMX7ULP_PAD_PTC2__LPUART4_TX 0x1 >; - bias-pull-up; }; }; diff --git a/Documentation/devicetree/bindings/pinctrl/mscc,ocelot-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/mscc,ocelot-pinctrl.txt index 24a210e0c59a..32a8a8fa7805 100644 --- a/Documentation/devicetree/bindings/pinctrl/mscc,ocelot-pinctrl.txt +++ b/Documentation/devicetree/bindings/pinctrl/mscc,ocelot-pinctrl.txt @@ -2,7 +2,8 @@ Microsemi Ocelot pin controller Device Tree Bindings ---------------------------------------------------- Required properties: - - compatible : Should be "mscc,ocelot-pinctrl" + - compatible : Should be "mscc,ocelot-pinctrl" or + "mscc,jaguar2-pinctrl" - reg : Address and length of the register set for the device - gpio-controller : Indicates this device is a GPIO controller - #gpio-cells : Must be 2. diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-mt6797.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-mt6797.txt new file mode 100644 index 000000000000..bd83401e6179 --- /dev/null +++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-mt6797.txt @@ -0,0 +1,83 @@ +* MediaTek MT6797 Pin Controller + +The MediaTek's MT6797 Pin controller is used to control SoC pins. + +Required properties: +- compatible: Value should be one of the following. + "mediatek,mt6797-pinctrl", compatible with mt6797 pinctrl. +- reg: Should contain address and size for gpio, iocfgl, iocfgb, + iocfgr and iocfgt register bases. +- reg-names: An array of strings describing the "reg" entries. Must + contain "gpio", "iocfgl", "iocfgb", "iocfgr", "iocfgt". +- gpio-controller: Marks the device node as a gpio controller. +- #gpio-cells: Should be two. The first cell is the gpio pin number + and the second cell is used for optional parameters. + +Optional properties: +- interrupt-controller: Marks the device node as an interrupt controller. +- #interrupt-cells: Should be two. +- interrupts : The interrupt outputs from the controller. + +Please refer to pinctrl-bindings.txt in this directory for details of the +common pinctrl bindings used by client devices. + +Subnode format +A pinctrl node should contain at least one subnodes representing the +pinctrl groups available on the machine. Each subnode will list the +pins it needs, and how they should be configured, with regard to muxer +configuration, pullups, drive strength, input enable/disable and input schmitt. + + node { + pinmux = <PIN_NUMBER_PINMUX>; + GENERIC_PINCONFIG; + }; + +Required properties: +- pinmux: Integer array, represents gpio pin number and mux setting. + Supported pin number and mux varies for different SoCs, and are defined + as macros in dt-bindings/pinctrl/<soc>-pinfunc.h directly. + +Optional properties: +- GENERIC_PINCONFIG: is the generic pinconfig options to use, bias-disable, + bias-pull, bias-pull-down, input-enable, input-schmitt-enable, + input-schmitt-disable, output-enable output-low, output-high, + drive-strength, and slew-rate are valid. + + Valid arguments for 'slew-rate' are '0' for no slew rate controlled and + '1' for slower slew rate respectively. Valid arguments for 'drive-strength' + is limited, such as 2, 4, 8, 12, or 16 in mA. + + Some optional vendor properties as defined are valid to specify in a + pinconf subnode: + - mediatek,tdsel: An integer describing the steps for output level shifter + duty cycle when asserted (high pulse width adjustment). Valid arguments + are from 0 to 15. + - mediatek,rdsel: An integer describing the steps for input level shifter + duty cycle when asserted (high pulse width adjustment). Valid arguments + are from 0 to 63. + - mediatek,pull-up-adv: An integer describing the code R1R0 as 0, 1, 2 + or 3 for the advanced pull-up resistors. + - mediatek,pull-down-adv: An integer describing the code R1R0 as 0, 1, 2, + or 3 for the advanced pull-down resistors. + +Examples: + + pio: pinctrl@10005000 { + compatible = "mediatek,mt6797-pinctrl"; + reg = <0 0x10005000 0 0x1000>, + <0 0x10002000 0 0x400>, + <0 0x10002400 0 0x400>, + <0 0x10002800 0 0x400>, + <0 0x10002C00 0 0x400>; + reg-names = "gpio", "iocfgl", "iocfgb", + "iocfgr", "iocfgt"; + gpio-controller; + #gpio-cells = <2>; + + uart1_pins_a: uart1 { + pins1 { + pinmux = <MT6797_GPIO232__FUNC_URXD1>, + <MT6797_GPIO233__FUNC_UTXD1>; + }; + }; + }; diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-mt7622.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-mt7622.txt index 3b695131c51b..7a7aca1ed705 100644 --- a/Documentation/devicetree/bindings/pinctrl/pinctrl-mt7622.txt +++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-mt7622.txt @@ -3,6 +3,7 @@ Required properties for the root node: - compatible: Should be one of the following "mediatek,mt7622-pinctrl" for MT7622 SoC + "mediatek,mt7629-pinctrl" for MT7629 SoC - reg: offset and length of the pinctrl space - gpio-controller: Marks the device node as a GPIO controller. @@ -324,6 +325,136 @@ group. "uart4_2_rts_cts" "uart" 95, 96 "watchdog" "watchdog" 78 + +== Valid values for pins, function and groups on MT7629 == + + Pin #: Valid values for pins + ----------------------------- + PIN 0: "TOP_5G_CLK" + PIN 1: "TOP_5G_DATA" + PIN 2: "WF0_5G_HB0" + PIN 3: "WF0_5G_HB1" + PIN 4: "WF0_5G_HB2" + PIN 5: "WF0_5G_HB3" + PIN 6: "WF0_5G_HB4" + PIN 7: "WF0_5G_HB5" + PIN 8: "WF0_5G_HB6" + PIN 9: "XO_REQ" + PIN 10: "TOP_RST_N" + PIN 11: "SYS_WATCHDOG" + PIN 12: "EPHY_LED0_N_JTDO" + PIN 13: "EPHY_LED1_N_JTDI" + PIN 14: "EPHY_LED2_N_JTMS" + PIN 15: "EPHY_LED3_N_JTCLK" + PIN 16: "EPHY_LED4_N_JTRST_N" + PIN 17: "WF2G_LED_N" + PIN 18: "WF5G_LED_N" + PIN 19: "I2C_SDA" + PIN 20: "I2C_SCL" + PIN 21: "GPIO_9" + PIN 22: "GPIO_10" + PIN 23: "GPIO_11" + PIN 24: "GPIO_12" + PIN 25: "UART1_TXD" + PIN 26: "UART1_RXD" + PIN 27: "UART1_CTS" + PIN 28: "UART1_RTS" + PIN 29: "UART2_TXD" + PIN 30: "UART2_RXD" + PIN 31: "UART2_CTS" + PIN 32: "UART2_RTS" + PIN 33: "MDI_TP_P1" + PIN 34: "MDI_TN_P1" + PIN 35: "MDI_RP_P1" + PIN 36: "MDI_RN_P1" + PIN 37: "MDI_RP_P2" + PIN 38: "MDI_RN_P2" + PIN 39: "MDI_TP_P2" + PIN 40: "MDI_TN_P2" + PIN 41: "MDI_TP_P3" + PIN 42: "MDI_TN_P3" + PIN 43: "MDI_RP_P3" + PIN 44: "MDI_RN_P3" + PIN 45: "MDI_RP_P4" + PIN 46: "MDI_RN_P4" + PIN 47: "MDI_TP_P4" + PIN 48: "MDI_TN_P4" + PIN 49: "SMI_MDC" + PIN 50: "SMI_MDIO" + PIN 51: "PCIE_PERESET_N" + PIN 52: "PWM_0" + PIN 53: "GPIO_0" + PIN 54: "GPIO_1" + PIN 55: "GPIO_2" + PIN 56: "GPIO_3" + PIN 57: "GPIO_4" + PIN 58: "GPIO_5" + PIN 59: "GPIO_6" + PIN 60: "GPIO_7" + PIN 61: "GPIO_8" + PIN 62: "SPI_CLK" + PIN 63: "SPI_CS" + PIN 64: "SPI_MOSI" + PIN 65: "SPI_MISO" + PIN 66: "SPI_WP" + PIN 67: "SPI_HOLD" + PIN 68: "UART0_TXD" + PIN 69: "UART0_RXD" + PIN 70: "TOP_2G_CLK" + PIN 71: "TOP_2G_DATA" + PIN 72: "WF0_2G_HB0" + PIN 73: "WF0_2G_HB1" + PIN 74: "WF0_2G_HB2" + PIN 75: "WF0_2G_HB3" + PIN 76: "WF0_2G_HB4" + PIN 77: "WF0_2G_HB5" + PIN 78: "WF0_2G_HB6" + +Valid values for function are: + "eth", "i2c", "led", "flash", "pcie", "pwm", "spi", "uart", + "watchdog", "wifi" + +Valid values for groups are: + Valid value function pins (in pin#) + ---------------------------------------------------------------- + "mdc_mdio" "eth" 23, 24 + "i2c_0" "i2c" 19, 20 + "i2c_1" "i2c" 53, 54 + "ephy_leds" "led" 12, 13, 14, 15, 16, + 17, 18 + "ephy0_led" "led" 12 + "ephy1_led" "led" 13 + "ephy2_led" "led" 14 + "ephy3_led" "led" 15 + "ephy4_led" "led" 16 + "wf2g_led" "led" 17 + "wf5g_led" "led" 18 + "snfi" "flash" 62, 63, 64, 65, 66, 67 + "spi_nor" "flash" 62, 63, 64, 65, 66, 67 + "pcie_pereset" "pcie" 51 + "pcie_wake" "pcie" 55 + "pcie_clkreq" "pcie" 56 + "pwm_0" "pwm" 52 + "pwm_1" "pwm" 61 + "spi_0" "spi" 21, 22, 23, 24 + "spi_1" "spi" 62, 63, 64, 65 + "spi_wp" "spi" 66 + "spi_hold" "spi" 67 + "uart0_txd_rxd" "uart" 68, 69 + "uart1_0_txd_rxd" "uart" 25, 26 + "uart1_0_cts_rts" "uart" 27, 28 + "uart1_1_txd_rxd" "uart" 53, 54 + "uart1_1_cts_rts" "uart" 55, 56 + "uart2_0_txd_rxd" "uart" 29, 30 + "uart2_0_cts_rts" "uart" 31, 32 + "uart2_1_txd_rxd" "uart" 57, 58 + "uart2_1_cts_rts" "uart" 59, 60 + "watchdog" "watchdog" 11 + "wf0_2g" "wifi" 70, 71, 72, 73, 74, + 75, 76, 77, 78 + "wf0_5g" "wifi" 0, 1, 2, 3, 4, 5, 6, + 7, 8, 9, 10 + Example: pio: pinctrl@10211000 { diff --git a/Documentation/devicetree/bindings/pinctrl/qcom,pmic-gpio.txt b/Documentation/devicetree/bindings/pinctrl/qcom,pmic-gpio.txt index ab4000eab07d..759aa1732e48 100644 --- a/Documentation/devicetree/bindings/pinctrl/qcom,pmic-gpio.txt +++ b/Documentation/devicetree/bindings/pinctrl/qcom,pmic-gpio.txt @@ -92,7 +92,7 @@ to specify in a pin configuration subnode: gpio1-gpio26 for pm8998 gpio1-gpio22 for pma8084 gpio1-gpio10 for pmi8994 - gpio1-gpio11 for pms405 + gpio1-gpio12 for pms405 (holes on gpio1, gpio9 and gpio10) - function: Usage: required diff --git a/Documentation/devicetree/bindings/pinctrl/renesas,rza2-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/renesas,rza2-pinctrl.txt new file mode 100644 index 000000000000..a63ccd476cda --- /dev/null +++ b/Documentation/devicetree/bindings/pinctrl/renesas,rza2-pinctrl.txt @@ -0,0 +1,87 @@ +Renesas RZ/A2 combined Pin and GPIO controller + +The Renesas SoCs of the RZ/A2 series feature a combined Pin and GPIO controller. +Pin multiplexing and GPIO configuration is performed on a per-pin basis. +Each port features up to 8 pins, each of them configurable for GPIO +function (port mode) or in alternate function mode. +Up to 8 different alternate function modes exist for each single pin. + +Pin controller node +------------------- + +Required properties: + - compatible: shall be: + - "renesas,r7s9210-pinctrl": for RZ/A2M + - reg + Address base and length of the memory area where the pin controller + hardware is mapped to. + - gpio-controller + This pin controller also controls pins as GPIO + - #gpio-cells + Must be 2 + - gpio-ranges + Expresses the total number of GPIO ports/pins in this SoC + +Example: Pin controller node for RZ/A2M SoC (r7s9210) + + pinctrl: pin-controller@fcffe000 { + compatible = "renesas,r7s9210-pinctrl"; + reg = <0xfcffe000 0x1000>; + + gpio-controller; + #gpio-cells = <2>; + gpio-ranges = <&pinctrl 0 0 176>; + }; + +Sub-nodes +--------- + +The child nodes of the pin controller designate pins to be used for +specific peripheral functions or as GPIO. + +- Pin multiplexing sub-nodes: + A pin multiplexing sub-node describes how to configure a set of + (or a single) pin in some desired alternate function mode. + The values for the pinmux properties are a combination of port name, pin + number and the desired function index. Use the RZA2_PINMUX macro located + in include/dt-bindings/pinctrl/r7s9210-pinctrl.h to easily define these. + For assigning GPIO pins, use the macro RZA2_PIN also in r7s9210-pinctrl.h + to express the desired port pin. + + Required properties: + - pinmux: + integer array representing pin number and pin multiplexing configuration. + When a pin has to be configured in alternate function mode, use this + property to identify the pin by its global index, and provide its + alternate function configuration number along with it. + When multiple pins are required to be configured as part of the same + alternate function they shall be specified as members of the same + argument list of a single "pinmux" property. + Helper macros to ease assembling the pin index from its position + (port where it sits on and pin number) and alternate function identifier + are provided by the pin controller header file at: + <dt-bindings/pinctrl/r7s9210-pinctrl.h> + Integers values in "pinmux" argument list are assembled as: + ((PORT * 8 + PIN) | MUX_FUNC << 16) + + Example: Board specific pins configuration + + &pinctrl { + /* Serial Console */ + scif4_pins: serial4 { + pinmux = <RZA2_PINMUX(PORT9, 0, 4)>, /* TxD4 */ + <RZA2_PINMUX(PORT9, 1, 4)>; /* RxD4 */ + }; + }; + + Example: Assigning a GPIO: + + leds { + status = "okay"; + compatible = "gpio-leds"; + + led0 { + /* P6_0 */ + gpios = <&pinctrl RZA2_PIN(PORT6, 0) GPIO_ACTIVE_HIGH>; + }; + }; diff --git a/Documentation/devicetree/bindings/pinctrl/st,stm32-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/st,stm32-pinctrl.txt index ef4f2ff4a1aa..48df30a36b01 100644 --- a/Documentation/devicetree/bindings/pinctrl/st,stm32-pinctrl.txt +++ b/Documentation/devicetree/bindings/pinctrl/st,stm32-pinctrl.txt @@ -56,6 +56,7 @@ Optional properties: More details in Documentation/devicetree/bindings/gpio/gpio.txt. - st,bank-ioport: should correspond to the EXTI IOport selection (EXTI line used to select GPIOs as interrupts). + - hwlocks: reference to a phandle of a hardware spinlock provider node. Example 1: #include <dt-bindings/pinctrl/stm32f429-pinfunc.h> diff --git a/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt b/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt index 9acce75b29ab..7c947a996df1 100644 --- a/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt +++ b/Documentation/devicetree/bindings/power/fsl,imx-gpcv2.txt @@ -6,7 +6,9 @@ Control (PGC) for various power domains. Required properties: -- compatible: Should be "fsl,imx7d-gpc" +- compatible: Should be one of: + - "fsl,imx7d-gpc" + - "fsl,imx8mq-gpc" - reg: should be register base and length as documented in the datasheet @@ -22,7 +24,8 @@ which, in turn, is expected to contain the following: Required properties: - reg: Power domain index. Valid values are defined in - include/dt-bindings/power/imx7-power.h + include/dt-bindings/power/imx7-power.h for fsl,imx7d-gpc and + include/dt-bindings/power/imx8m-power.h for fsl,imx8mq-gpc - #power-domain-cells: Should be 0 diff --git a/Documentation/devicetree/bindings/power/reset/gpio-poweroff.txt b/Documentation/devicetree/bindings/power/reset/gpio-poweroff.txt index 6d8980c18c34..3e56c1b34a4c 100644 --- a/Documentation/devicetree/bindings/power/reset/gpio-poweroff.txt +++ b/Documentation/devicetree/bindings/power/reset/gpio-poweroff.txt @@ -27,6 +27,8 @@ Optional properties: it to an output when the power-off handler is called. If this optional property is not specified, the GPIO is initialized as an output in its inactive state. +- active-delay-ms: Delay (default 100) to wait after driving gpio active +- inactive-delay-ms: Delay (default 100) to wait after driving gpio inactive - timeout-ms: Time to wait before asserting a WARN_ON(1). If nothing is specified, 3000 ms is used. diff --git a/Documentation/devicetree/bindings/power/supply/axp20x_ac_power.txt b/Documentation/devicetree/bindings/power/supply/axp20x_ac_power.txt index 826e8a879121..7a1fb532abe5 100644 --- a/Documentation/devicetree/bindings/power/supply/axp20x_ac_power.txt +++ b/Documentation/devicetree/bindings/power/supply/axp20x_ac_power.txt @@ -4,6 +4,7 @@ Required Properties: - compatible: One of: "x-powers,axp202-ac-power-supply" "x-powers,axp221-ac-power-supply" + "x-powers,axp813-ac-power-supply" This node is a subnode of the axp20x PMIC. @@ -13,6 +14,8 @@ reading ADC channels from the AXP20X ADC. The AXP22X is only able to tell if an AC power supply is present and usable. +AXP813/AXP803 are able to limit current and supply voltage + Example: &axp209 { diff --git a/Documentation/devicetree/bindings/power/supply/battery.txt b/Documentation/devicetree/bindings/power/supply/battery.txt index f4d3b4a10b43..89871ab8c704 100644 --- a/Documentation/devicetree/bindings/power/supply/battery.txt +++ b/Documentation/devicetree/bindings/power/supply/battery.txt @@ -22,6 +22,18 @@ Optional Properties: - charge-term-current-microamp: current for charge termination phase - constant-charge-current-max-microamp: maximum constant input current - constant-charge-voltage-max-microvolt: maximum constant input voltage + - factory-internal-resistance-micro-ohms: battery factory internal resistance + - ocv-capacity-table-0: An array providing the open circuit voltage (OCV) + of the battery and corresponding battery capacity percent, which is used + to look up battery capacity according to current OCV value. And the open + circuit voltage unit is microvolt. + - ocv-capacity-table-1: Same as ocv-capacity-table-0 + ...... + - ocv-capacity-table-n: Same as ocv-capacity-table-0 + - ocv-capacity-celsius: An array containing the temperature in degree Celsius, + for each of the battery capacity lookup table. The first temperature value + specifies the OCV table 0, and the second temperature value specifies the + OCV table 1, and so on. Battery properties are named, where possible, for the corresponding elements in enum power_supply_property, defined in @@ -42,6 +54,11 @@ Example: charge-term-current-microamp = <128000>; constant-charge-current-max-microamp = <900000>; constant-charge-voltage-max-microvolt = <4200000>; + factory-internal-resistance-micro-ohms = <250000>; + ocv-capacity-celsius = <(-10) 0 10>; + ocv-capacity-table-0 = <4185000 100>, <4113000 95>, <4066000 90>, ...; + ocv-capacity-table-1 = <4200000 100>, <4185000 95>, <4113000 90>, ...; + ocv-capacity-table-2 = <4250000 100>, <4200000 95>, <4185000 90>, ...; }; charger: charger@11 { diff --git a/Documentation/devicetree/bindings/power/supply/bq24190.txt b/Documentation/devicetree/bindings/power/supply/bq24190.txt index 9e517d307070..ffe2be408bb6 100644 --- a/Documentation/devicetree/bindings/power/supply/bq24190.txt +++ b/Documentation/devicetree/bindings/power/supply/bq24190.txt @@ -3,7 +3,9 @@ TI BQ24190 Li-Ion Battery Charger Required properties: - compatible: contains one of the following: * "ti,bq24190" + * "ti,bq24192" * "ti,bq24192i" + * "ti,bq24196" - reg: integer, I2C address of the charger. - interrupts[-extended]: configuration for charger INT pin. @@ -19,6 +21,12 @@ Optional properties: - ti,system-minimum-microvolt: when power is connected and the battery is below minimum system voltage, the system will be regulated above this setting. +child nodes: +- usb-otg-vbus: + Usage: optional + Description: Regulator that is used to control the VBUS voltage direction for + either USB host mode or for charging on the OTG port. + Notes: - Some circuit boards wire the chip's "OTG" pin high (enabling 500mA default charge current on USB SDP ports, among other features). To simulate this on @@ -39,6 +47,8 @@ Example: interrupts-extended = <&gpiochip 10 IRQ_TYPE_EDGE_FALLING>; monitored-battery = <&bat>; ti,system-minimum-microvolt = <3200000>; + + usb_otg_vbus: usb-otg-vbus { }; }; &twl_gpio { diff --git a/Documentation/devicetree/bindings/power/supply/sc27xx-fg.txt b/Documentation/devicetree/bindings/power/supply/sc27xx-fg.txt new file mode 100644 index 000000000000..fc35ac577401 --- /dev/null +++ b/Documentation/devicetree/bindings/power/supply/sc27xx-fg.txt @@ -0,0 +1,56 @@ +Spreadtrum SC27XX PMICs Fuel Gauge Unit Power Supply Bindings + +Required properties: +- compatible: Should be one of the following: + "sprd,sc2720-fgu", + "sprd,sc2721-fgu", + "sprd,sc2723-fgu", + "sprd,sc2730-fgu", + "sprd,sc2731-fgu". +- reg: The address offset of fuel gauge unit. +- battery-detect-gpios: GPIO for battery detection. +- io-channels: Specify the IIO ADC channel to get temperature. +- io-channel-names: Should be "bat-temp". +- nvmem-cells: A phandle to the calibration cells provided by eFuse device. +- nvmem-cell-names: Should be "fgu_calib". +- monitored-battery: Phandle of battery characteristics devicetree node. + See Documentation/devicetree/bindings/power/supply/battery.txt + +Example: + + bat: battery { + compatible = "simple-battery"; + charge-full-design-microamp-hours = <1900000>; + constant-charge-voltage-max-microvolt = <4350000>; + ocv-capacity-celsius = <20>; + ocv-capacity-table-0 = <4185000 100>, <4113000 95>, <4066000 90>, + <4022000 85>, <3983000 80>, <3949000 75>, + <3917000 70>, <3889000 65>, <3864000 60>, + <3835000 55>, <3805000 50>, <3787000 45>, + <3777000 40>, <3773000 35>, <3770000 30>, + <3765000 25>, <3752000 20>, <3724000 15>, + <3680000 10>, <3605000 5>, <3400000 0>; + ...... + }; + + sc2731_pmic: pmic@0 { + compatible = "sprd,sc2731"; + reg = <0>; + spi-max-frequency = <26000000>; + interrupts = <GIC_SPI 31 IRQ_TYPE_LEVEL_HIGH>; + interrupt-controller; + #interrupt-cells = <2>; + #address-cells = <1>; + #size-cells = <0>; + + fgu@a00 { + compatible = "sprd,sc2731-fgu"; + reg = <0xa00>; + battery-detect-gpios = <&pmic_eic 9 GPIO_ACTIVE_HIGH>; + io-channels = <&pmic_adc 5>; + io-channel-names = "bat-temp"; + nvmem-cells = <&fgu_calib>; + nvmem-cell-names = "fgu_calib"; + monitored-battery = <&bat>; + }; + }; diff --git a/Documentation/devicetree/bindings/reserved-memory/xen,shared-memory.txt b/Documentation/devicetree/bindings/reserved-memory/xen,shared-memory.txt new file mode 100644 index 000000000000..d483a2103d70 --- /dev/null +++ b/Documentation/devicetree/bindings/reserved-memory/xen,shared-memory.txt @@ -0,0 +1,24 @@ +* Xen hypervisor reserved-memory binding + +Expose one or more memory regions as reserved-memory to the guest +virtual machine. Typically, a region is configured at VM creation time +to be a shared memory area across multiple virtual machines for +communication among them. + +For each of these pre-shared memory regions, a range is exposed under +the /reserved-memory node as a child node. Each range sub-node is named +xen-shmem@<address> and has the following properties: + +- compatible: + compatible = "xen,shared-memory-v1" + +- reg: + the base guest physical address and size of the shared memory region + +- xen,offset: (borrower VMs only) + 64 bit integer offset within the owner virtual machine's shared + memory region used for the mapping in the borrower VM. + +- xen,id: + a string that identifies the shared memory region as specified in + the VM config file diff --git a/Documentation/devicetree/bindings/rng/mtk-rng.txt b/Documentation/devicetree/bindings/rng/mtk-rng.txt index 366b99bff8cd..2bc89f133701 100644 --- a/Documentation/devicetree/bindings/rng/mtk-rng.txt +++ b/Documentation/devicetree/bindings/rng/mtk-rng.txt @@ -1,9 +1,10 @@ Device-Tree bindings for Mediatek random number generator -found in Mediatek SoC family +found in MediaTek SoC family Required properties: - compatible : Should be "mediatek,mt7622-rng", "mediatek,mt7623-rng" : for MT7622 + "mediatek,mt7629-rng", "mediatek,mt7623-rng" : for MT7629 "mediatek,mt7623-rng" : for MT7623 - clocks : list of clock specifiers, corresponding to entries in clock-names property; diff --git a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt index be789685a1c2..18b892d010d8 100644 --- a/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt +++ b/Documentation/devicetree/bindings/rtc/abracon,abx80x.txt @@ -27,4 +27,4 @@ and valid to enable charging: - "abracon,tc-diode": should be "standard" (0.6V) or "schottky" (0.3V) - "abracon,tc-resistor": should be <0>, <3>, <6> or <11>. 0 disables the output - resistor, the other values are in ohm. + resistor, the other values are in kOhm. diff --git a/Documentation/devicetree/bindings/rtc/nxp,rtc-2123.txt b/Documentation/devicetree/bindings/rtc/nxp,rtc-2123.txt index 811124a36d16..1994f601800a 100644 --- a/Documentation/devicetree/bindings/rtc/nxp,rtc-2123.txt +++ b/Documentation/devicetree/bindings/rtc/nxp,rtc-2123.txt @@ -2,6 +2,7 @@ NXP PCF2123 SPI Real Time Clock Required properties: - compatible: should be: "nxp,rtc-pcf2123" + or "microcrystal,rv2123" - reg: should be the SPI slave chipselect address Optional properties: diff --git a/Documentation/devicetree/bindings/rtc/pcf85363.txt b/Documentation/devicetree/bindings/rtc/pcf85363.txt index 76fdabc59742..94adc1cf93d9 100644 --- a/Documentation/devicetree/bindings/rtc/pcf85363.txt +++ b/Documentation/devicetree/bindings/rtc/pcf85363.txt @@ -1,8 +1,8 @@ -NXP PCF85363 Real Time Clock +NXP PCF85263/PCF85363 Real Time Clock ============================ Required properties: -- compatible: Should contain "nxp,pcf85363". +- compatible: Should contain "nxp,pcf85263" or "nxp,pcf85363". - reg: I2C address for chip. Optional properties: diff --git a/Documentation/devicetree/bindings/rtc/rtc-ds1307.txt b/Documentation/devicetree/bindings/rtc/rtc-ds1307.txt index eebfbe04207a..eaee19b60960 100644 --- a/Documentation/devicetree/bindings/rtc/rtc-ds1307.txt +++ b/Documentation/devicetree/bindings/rtc/rtc-ds1307.txt @@ -35,7 +35,7 @@ Optional properties: Should be given if internal trickle charger diode should be disabled Example: - rtc1: ds1339@68 { + ds1339: rtc@68 { compatible = "dallas,ds1339"; reg = <0x68>; interrupt-parent = <&gpio4>; diff --git a/Documentation/devicetree/bindings/rtc/rtc.txt b/Documentation/devicetree/bindings/rtc/rtc.txt new file mode 100644 index 000000000000..7c8da6926095 --- /dev/null +++ b/Documentation/devicetree/bindings/rtc/rtc.txt @@ -0,0 +1,64 @@ +Generic device tree bindings for Real Time Clock devices +======================================================== + +This document describes generic bindings which can be used to describe Real Time +Clock devices in a device tree. + +Required properties +------------------- + +- compatible : name of RTC device following generic names recommended practice. + +For other required properties e.g. to describe register sets, +clocks, etc. check the binding documentation of the specific driver. + +Optional properties +------------------- + +- start-year : if provided, the default hardware range supported by the RTC is + shifted so the first usable year is the specified one. + +The following properties may not be supported by all drivers. However, if a +driver wants to support one of the below features, it should adapt the bindings +below. +- trickle-resistor-ohms : Selected resistor for trickle charger. Should be given + if trickle charger should be enabled +- trickle-diode-disable : Do not use internal trickle charger diode Should be + given if internal trickle charger diode should be + disabled +- wakeup-source : Enables wake up of host system on alarm + +Trivial RTCs +------------ + +This is a list of trivial RTC devices that have simple device tree +bindings, consisting only of a compatible field, an address and +possibly an interrupt line. + + +Compatible Vendor / Chip +========== ============= +abracon,abb5zes3 AB-RTCMC-32.768kHz-B5ZE-S3: Real Time Clock/Calendar Module with I2C Interface +dallas,ds1374 I2C, 32-Bit Binary Counter Watchdog RTC with Trickle Charger and Reset Input/Output +dallas,ds1672 Dallas DS1672 Real-time Clock +dallas,ds3232 Extremely Accurate I²C RTC with Integrated Crystal and SRAM +epson,rx8010 I2C-BUS INTERFACE REAL TIME CLOCK MODULE +epson,rx8581 I2C-BUS INTERFACE REAL TIME CLOCK MODULE +emmicro,em3027 EM Microelectronic EM3027 Real-time Clock +isil,isl1208 Intersil ISL1208 Low Power RTC with Battery Backed SRAM +isil,isl1218 Intersil ISL1218 Low Power RTC with Battery Backed SRAM +isil,isl12022 Intersil ISL12022 Real-time Clock +microcrystal,rv3029 Real Time Clock Module with I2C-Bus +nxp,pcf2127 Real-time clock +nxp,pcf2129 Real-time clock +nxp,pcf8523 Real-time Clock +nxp,pcf8563 Real-time clock/calendar +nxp,pcf85063 Tiny Real-Time Clock +pericom,pt7c4338 Real-time Clock Module +ricoh,r2025sd I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC +ricoh,r2221tl I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC +ricoh,rs5c372a I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC +ricoh,rs5c372b I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC +ricoh,rv5c386 I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC +ricoh,rv5c387a I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC +sii,s35390a 2-wire CMOS real-time clock diff --git a/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt b/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt index 12c083c1140a..6b732c41392b 100644 --- a/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt +++ b/Documentation/devicetree/bindings/rtc/sun6i-rtc.txt @@ -3,25 +3,44 @@ RTC controller for the Allwinner A31 Required properties: -- compatible : Should be "allwinner,sun6i-a31-rtc" +- compatible : Should be one of the following combinations: + - "allwinner,sun6i-a31-rtc" + - "allwinner,sun8i-a23-rtc" + - "allwinner,sun8i-h3-rtc" + - "allwinner,sun8i-r40-rtc", "allwinner,sun8i-h3-rtc" + - "allwinner,sun8i-v3-rtc" + - "allwinner,sun50i-a64-rtc", "allwinner,sun8i-h3-rtc" + - "allwinner,sun50i-h5-rtc" + + Where there are two or more compatible strings, this + denotes the hardware covered by the most specific one + is backward-compatible with the latter ones, and the + implementation for the latter ones can be used, albeit + with reduced functionality. + - reg : physical base address of the controller and length of memory mapped region. - interrupts : IRQ lines for the RTC alarm 0 and alarm 1, in that order. Required properties for new device trees - clocks : phandle to the 32kHz external oscillator -- clock-output-names : names of the LOSC and its external output clocks created -- #clock-cells : must be equals to 1. The RTC provides two clocks: the - LOSC and its external output, with index 0 and 1 - respectively. +- clock-output-names : names of up to three clock outputs. See below. +- #clock-cells : must be equal to 1. + +The RTC provides the following clocks at the given indices: +- 0: LOSC +- 1: LOSC external output, known as X32KFOUT in the datasheet. + This clock is not available on the A31 and is deprecated for old + device trees still using the "allwinner,sun6i-a31-rtc" compatible. +- 2: InternalOSC, or internal RC oscillator (A64/H3/H5 only) Example: rtc: rtc@1f00000 { compatible = "allwinner,sun6i-a31-rtc"; - reg = <0x01f00000 0x54>; + reg = <0x01f00000 0x400>; interrupts = <0 40 4>, <0 41 4>; - clock-output-names = "osc32k", "osc32k-out"; + clock-output-names = "osc32k"; clocks = <&ext_osc32k>; #clock-cells = <1>; }; diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt index aeb6db4e35c3..da50321da34d 100644 --- a/Documentation/devicetree/bindings/serial/8250.txt +++ b/Documentation/devicetree/bindings/serial/8250.txt @@ -51,6 +51,7 @@ Optional properties: - tx-threshold: Specify the TX FIFO low water indication for parts with programmable TX FIFO thresholds. - resets : phandle + reset specifier pairs +- overrun-throttle-ms : how long to pause uart rx when input overrun is encountered. Note: * fsl,ns16550: diff --git a/Documentation/devicetree/bindings/serial/fsl-lpuart.txt b/Documentation/devicetree/bindings/serial/fsl-lpuart.txt index 6bd3f2e93d61..21483ba820bc 100644 --- a/Documentation/devicetree/bindings/serial/fsl-lpuart.txt +++ b/Documentation/devicetree/bindings/serial/fsl-lpuart.txt @@ -8,6 +8,8 @@ Required properties: on LS1021A SoC with 32-bit big-endian register organization - "fsl,imx7ulp-lpuart" for lpuart compatible with the one integrated on i.MX7ULP SoC with 32-bit little-endian register organization + - "fsl,imx8qxp-lpuart" for lpuart compatible with the one integrated + on i.MX8QXP SoC with 32-bit little-endian register organization - reg : Address and length of the register set for the device - interrupts : Should contain uart interrupt - clocks : phandle + clock specifier pairs, one for each entry in clock-names diff --git a/Documentation/devicetree/bindings/serial/lantiq_asc.txt b/Documentation/devicetree/bindings/serial/lantiq_asc.txt index 3acbd309ab9d..40e81a5818f6 100644 --- a/Documentation/devicetree/bindings/serial/lantiq_asc.txt +++ b/Documentation/devicetree/bindings/serial/lantiq_asc.txt @@ -6,8 +6,23 @@ Required properties: - interrupts: the 3 (tx rx err) interrupt numbers. The interrupt specifier depends on the interrupt-parent interrupt controller. +Optional properties: +- clocks: Should contain frequency clock and gate clock +- clock-names: Should be "freq" and "asc" + Example: +asc0: serial@16600000 { + compatible = "lantiq,asc"; + reg = <0x16600000 0x100000>; + interrupt-parent = <&gic>; + interrupts = <GIC_SHARED 103 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SHARED 105 IRQ_TYPE_LEVEL_HIGH>, + <GIC_SHARED 106 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&cgu CLK_SSX4>, <&cgu GCLK_UART>; + clock-names = "freq", "asc"; +}; + asc1: serial@e100c00 { compatible = "lantiq,asc"; reg = <0xE100C00 0x400>; diff --git a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt index e52e16c6bc57..20232ad05d89 100644 --- a/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt +++ b/Documentation/devicetree/bindings/serial/renesas,sci-serial.txt @@ -24,6 +24,10 @@ Required properties: - "renesas,hscif-r8a7745" for R8A7745 (RZ/G1E) HSCIF compatible UART. - "renesas,scif-r8a77470" for R8A77470 (RZ/G1C) SCIF compatible UART. - "renesas,hscif-r8a77470" for R8A77470 (RZ/G1C) HSCIF compatible UART. + - "renesas,scif-r8a774a1" for R8A774A1 (RZ/G2M) SCIF compatible UART. + - "renesas,hscif-r8a774a1" for R8A774A1 (RZ/G2M) HSCIF compatible UART. + - "renesas,scif-r8a774c0" for R8A774C0 (RZ/G2E) SCIF compatible UART. + - "renesas,hscif-r8a774c0" for R8A774C0 (RZ/G2E) HSCIF compatible UART. - "renesas,scif-r8a7778" for R8A7778 (R-Car M1) SCIF compatible UART. - "renesas,scif-r8a7779" for R8A7779 (R-Car H1) SCIF compatible UART. - "renesas,scif-r8a7790" for R8A7790 (R-Car H2) SCIF compatible UART. @@ -61,13 +65,13 @@ Required properties: - "renesas,scifa-sh73a0" for SH73A0 (SH-Mobile AG5) SCIFA compatible UART. - "renesas,scifb-sh73a0" for SH73A0 (SH-Mobile AG5) SCIFB compatible UART. - "renesas,rcar-gen1-scif" for R-Car Gen1 SCIF compatible UART, - - "renesas,rcar-gen2-scif" for R-Car Gen2 SCIF compatible UART, - - "renesas,rcar-gen3-scif" for R-Car Gen3 SCIF compatible UART, - - "renesas,rcar-gen2-scifa" for R-Car Gen2 SCIFA compatible UART, - - "renesas,rcar-gen2-scifb" for R-Car Gen2 SCIFB compatible UART, + - "renesas,rcar-gen2-scif" for R-Car Gen2 and RZ/G1 SCIF compatible UART, + - "renesas,rcar-gen3-scif" for R-Car Gen3 and RZ/G2 SCIF compatible UART, + - "renesas,rcar-gen2-scifa" for R-Car Gen2 and RZ/G1 SCIFA compatible UART, + - "renesas,rcar-gen2-scifb" for R-Car Gen2 and RZ/G1 SCIFB compatible UART, - "renesas,rcar-gen1-hscif" for R-Car Gen1 HSCIF compatible UART, - - "renesas,rcar-gen2-hscif" for R-Car Gen2 HSCIF compatible UART, - - "renesas,rcar-gen3-hscif" for R-Car Gen3 HSCIF compatible UART, + - "renesas,rcar-gen2-hscif" for R-Car Gen2 and RZ/G1 HSCIF compatible UART, + - "renesas,rcar-gen3-hscif" for R-Car Gen3 and RZ/G2 HSCIF compatible UART, - "renesas,scif" for generic SCIF compatible UART. - "renesas,scifa" for generic SCIFA compatible UART. - "renesas,scifb" for generic SCIFB compatible UART. diff --git a/Documentation/devicetree/bindings/serial/rs485.txt b/Documentation/devicetree/bindings/serial/rs485.txt index b7c29f74ebb2..b92592dff6dd 100644 --- a/Documentation/devicetree/bindings/serial/rs485.txt +++ b/Documentation/devicetree/bindings/serial/rs485.txt @@ -16,7 +16,7 @@ Optional properties: - linux,rs485-enabled-at-boot-time: empty property telling to enable the rs485 feature at boot time. It can be disabled later with proper ioctl. - rs485-rx-during-tx: empty property that enables the receiving of data even - whilst sending data. + while sending data. RS485 example for Atmel USART: usart0: serial@fff8c000 { diff --git a/Documentation/devicetree/bindings/serio/olpc,ap-sp.txt b/Documentation/devicetree/bindings/serio/olpc,ap-sp.txt index 0e72183f52bc..36603419d6f8 100644 --- a/Documentation/devicetree/bindings/serio/olpc,ap-sp.txt +++ b/Documentation/devicetree/bindings/serio/olpc,ap-sp.txt @@ -4,10 +4,14 @@ Required properties: - compatible : "olpc,ap-sp" - reg : base address and length of SoC's WTM registers - interrupts : SP-AP interrupt +- clocks : phandle + clock-specifier for the clock that drives the WTM +- clock-names: should be "sp" Example: ap-sp@d4290000 { compatible = "olpc,ap-sp"; reg = <0xd4290000 0x1000>; interrupts = <40>; + clocks = <&soc_clocks MMP2_CLK_SP>; + clock-names = "sp"; } diff --git a/Documentation/devicetree/bindings/soc/amlogic/clk-measure.txt b/Documentation/devicetree/bindings/soc/amlogic/clk-measure.txt new file mode 100644 index 000000000000..205a54bcd7c7 --- /dev/null +++ b/Documentation/devicetree/bindings/soc/amlogic/clk-measure.txt @@ -0,0 +1,18 @@ +Amlogic Internal Clock Measurer +=============================== + +The Amlogic SoCs contains an IP to measure the internal clocks. +The precision is multiple of MHz, useful to debug the clock states. + +Required properties: +- compatible: Shall contain one of the following : + "amlogic,meson-gx-clk-measure" for GX SoCs + "amlogic,meson8-clk-measure" for Meson8 SoCs + "amlogic,meson8b-clk-measure" for Meson8b SoCs +- reg: base address and size of the Clock Measurer register space. + +Example: + clock-measure@8758 { + compatible = "amlogic,meson-gx-clk-measure"; + reg = <0x0 0x8758 0x0 0x10>; + }; diff --git a/Documentation/devicetree/bindings/soc/bcm/brcm,bcm2835-vchiq.txt b/Documentation/devicetree/bindings/soc/bcm/brcm,bcm2835-vchiq.txt index 8dd7b3a7de65..f331316183f6 100644 --- a/Documentation/devicetree/bindings/soc/bcm/brcm,bcm2835-vchiq.txt +++ b/Documentation/devicetree/bindings/soc/bcm/brcm,bcm2835-vchiq.txt @@ -2,7 +2,8 @@ Broadcom VCHIQ firmware services Required properties: -- compatible: Should be "brcm,bcm2835-vchiq" +- compatible: Should be "brcm,bcm2835-vchiq" on BCM2835, otherwise + "brcm,bcm2836-vchiq". - reg: Physical base address and length of the doorbell register pair - interrupts: The interrupt number See bindings/interrupt-controller/brcm,bcm2835-armctrl-ic.txt diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smd-rpm.txt b/Documentation/devicetree/bindings/soc/qcom/qcom,smd-rpm.txt index 89e1cb9212f6..ec95705ba692 100644 --- a/Documentation/devicetree/bindings/soc/qcom/qcom,smd-rpm.txt +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smd-rpm.txt @@ -23,6 +23,7 @@ resources. "qcom,rpm-msm8916" "qcom,rpm-msm8974" "qcom,rpm-msm8998" + "qcom,rpm-qcs404" - qcom,smd-channels: Usage: required diff --git a/Documentation/devicetree/bindings/soc/rockchip/power_domain.txt b/Documentation/devicetree/bindings/soc/rockchip/power_domain.txt index 5d49d0a2ff29..8304eceb62e4 100644 --- a/Documentation/devicetree/bindings/soc/rockchip/power_domain.txt +++ b/Documentation/devicetree/bindings/soc/rockchip/power_domain.txt @@ -7,7 +7,9 @@ Required properties for power domain controller: - compatible: Should be one of the following. "rockchip,px30-power-controller" - for PX30 SoCs. "rockchip,rk3036-power-controller" - for RK3036 SoCs. + "rockchip,rk3066-power-controller" - for RK3066 SoCs. "rockchip,rk3128-power-controller" - for RK3128 SoCs. + "rockchip,rk3188-power-controller" - for RK3188 SoCs. "rockchip,rk3228-power-controller" - for RK3228 SoCs. "rockchip,rk3288-power-controller" - for RK3288 SoCs. "rockchip,rk3328-power-controller" - for RK3328 SoCs. @@ -23,7 +25,9 @@ Required properties for power domain sub nodes: - reg: index of the power domain, should use macros in: "include/dt-bindings/power/px30-power.h" - for PX30 type power domain. "include/dt-bindings/power/rk3036-power.h" - for RK3036 type power domain. + "include/dt-bindings/power/rk3066-power.h" - for RK3066 type power domain. "include/dt-bindings/power/rk3128-power.h" - for RK3128 type power domain. + "include/dt-bindings/power/rk3188-power.h" - for RK3188 type power domain. "include/dt-bindings/power/rk3228-power.h" - for RK3228 type power domain. "include/dt-bindings/power/rk3288-power.h" - for RK3288 type power domain. "include/dt-bindings/power/rk3328-power.h" - for RK3328 type power domain. diff --git a/Documentation/devicetree/bindings/sram/sunxi-sram.txt b/Documentation/devicetree/bindings/sram/sunxi-sram.txt index 62dd0748f0ef..ab5a70bb9a64 100644 --- a/Documentation/devicetree/bindings/sram/sunxi-sram.txt +++ b/Documentation/devicetree/bindings/sram/sunxi-sram.txt @@ -18,7 +18,9 @@ Required properties: - "allwinner,sun8i-h3-system-control" - "allwinner,sun50i-a64-sram-controller" (deprecated) - "allwinner,sun50i-a64-system-control" + - "allwinner,sun50i-h5-system-control" - "allwinner,sun50i-h6-system-control", "allwinner,sun50i-a64-system-control" + - "allwinner,suniv-f1c100s-system-control", "allwinner,sun4i-a10-system-control" - reg : sram controller register offset + length SRAM nodes @@ -54,10 +56,17 @@ The valid sections compatible for H3 are: The valid sections compatible for A64 are: - allwinner,sun50i-a64-sram-c + - allwinner,sun50i-a64-sram-c1, allwinner,sun4i-a10-sram-c1 + +The valid sections compatible for H5 are: + - allwinner,sun50i-h5-sram-c1, allwinner,sun4i-a10-sram-c1 The valid sections compatible for H6 are: - allwinner,sun50i-h6-sram-c, allwinner,sun50i-a64-sram-c +The valid sections compatible for F1C100s are: + - allwinner,suniv-f1c100s-sram-d, allwinner,sun4i-a10-sram-d + Devices using SRAM sections --------------------------- diff --git a/Documentation/devicetree/bindings/thermal/nvidia,tegra186-bpmp-thermal.txt b/Documentation/devicetree/bindings/thermal/nvidia,tegra186-bpmp-thermal.txt index 276387dd6815..e17c07be270b 100644 --- a/Documentation/devicetree/bindings/thermal/nvidia,tegra186-bpmp-thermal.txt +++ b/Documentation/devicetree/bindings/thermal/nvidia,tegra186-bpmp-thermal.txt @@ -15,7 +15,8 @@ Required properties: - compatible: Array of strings. One of: - - "nvidia,tegra186-bpmp-thermal". + - "nvidia,tegra186-bpmp-thermal" + - "nvidia,tegra194-bpmp-thermal" - #thermal-sensor-cells: Cell for sensor index. Single-cell integer. Must be <1>. diff --git a/Documentation/devicetree/bindings/timer/amlogic,meson6-timer.txt b/Documentation/devicetree/bindings/timer/amlogic,meson6-timer.txt index a092053f7902..a9da22bda912 100644 --- a/Documentation/devicetree/bindings/timer/amlogic,meson6-timer.txt +++ b/Documentation/devicetree/bindings/timer/amlogic,meson6-timer.txt @@ -4,12 +4,19 @@ Required properties: - compatible : should be "amlogic,meson6-timer" - reg : Specifies base physical address and size of the registers. -- interrupts : The interrupt of the first timer +- interrupts : The four interrupts, one for each timer event +- clocks : phandles to the pclk (system clock) and XTAL clocks +- clock-names : must contain "pclk" and "xtal" Example: timer@c1109940 { compatible = "amlogic,meson6-timer"; reg = <0xc1109940 0x14>; - interrupts = <0 10 1>; + interrupts = <GIC_SPI 10 IRQ_TYPE_EDGE_RISING>, + <GIC_SPI 11 IRQ_TYPE_EDGE_RISING>, + <GIC_SPI 6 IRQ_TYPE_EDGE_RISING>, + <GIC_SPI 29 IRQ_TYPE_EDGE_RISING>; + clocks = <&xtal>, <&clk81>; + clock-names = "xtal", "pclk"; }; diff --git a/Documentation/devicetree/bindings/timer/arm,arch_timer.txt b/Documentation/devicetree/bindings/timer/arm,arch_timer.txt deleted file mode 100644 index 68301b77e854..000000000000 --- a/Documentation/devicetree/bindings/timer/arm,arch_timer.txt +++ /dev/null @@ -1,112 +0,0 @@ -* ARM architected timer - -ARM cores may have a per-core architected timer, which provides per-cpu timers, -or a memory mapped architected timer, which provides up to 8 frames with a -physical and optional virtual timer per frame. - -The per-core architected timer is attached to a GIC to deliver its -per-processor interrupts via PPIs. The memory mapped timer is attached to a GIC -to deliver its interrupts via SPIs. - -** CP15 Timer node properties: - -- compatible : Should at least contain one of - "arm,armv7-timer" - "arm,armv8-timer" - -- interrupts : Interrupt list for secure, non-secure, virtual and - hypervisor timers, in that order. - -- clock-frequency : The frequency of the main counter, in Hz. Should be present - only where necessary to work around broken firmware which does not configure - CNTFRQ on all CPUs to a uniform correct value. Use of this property is - strongly discouraged; fix your firmware unless absolutely impossible. - -- always-on : a boolean property. If present, the timer is powered through an - always-on power domain, therefore it never loses context. - -- fsl,erratum-a008585 : A boolean property. Indicates the presence of - QorIQ erratum A-008585, which says that reading the counter is - unreliable unless the same value is returned by back-to-back reads. - This also affects writes to the tval register, due to the implicit - counter read. - -- hisilicon,erratum-161010101 : A boolean property. Indicates the - presence of Hisilicon erratum 161010101, which says that reading the - counters is unreliable in some cases, and reads may return a value 32 - beyond the correct value. This also affects writes to the tval - registers, due to the implicit counter read. - -** Optional properties: - -- arm,cpu-registers-not-fw-configured : Firmware does not initialize - any of the generic timer CPU registers, which contain their - architecturally-defined reset values. Only supported for 32-bit - systems which follow the ARMv7 architected reset values. - -- arm,no-tick-in-suspend : The main counter does not tick when the system is in - low-power system suspend on some SoCs. This behavior does not match the - Architecture Reference Manual's specification that the system counter "must - be implemented in an always-on power domain." - - -Example: - - timer { - compatible = "arm,cortex-a15-timer", - "arm,armv7-timer"; - interrupts = <1 13 0xf08>, - <1 14 0xf08>, - <1 11 0xf08>, - <1 10 0xf08>; - clock-frequency = <100000000>; - }; - -** Memory mapped timer node properties: - -- compatible : Should at least contain "arm,armv7-timer-mem". - -- clock-frequency : The frequency of the main counter, in Hz. Should be present - only when firmware has not configured the MMIO CNTFRQ registers. - -- reg : The control frame base address. - -Note that #address-cells, #size-cells, and ranges shall be present to ensure -the CPU can address a frame's registers. - -A timer node has up to 8 frame sub-nodes, each with the following properties: - -- frame-number: 0 to 7. - -- interrupts : Interrupt list for physical and virtual timers in that order. - The virtual timer interrupt is optional. - -- reg : The first and second view base addresses in that order. The second view - base address is optional. - -- status : "disabled" indicates the frame is not available for use. Optional. - -Example: - - timer@f0000000 { - compatible = "arm,armv7-timer-mem"; - #address-cells = <1>; - #size-cells = <1>; - ranges; - reg = <0xf0000000 0x1000>; - clock-frequency = <50000000>; - - frame@f0001000 { - frame-number = <0> - interrupts = <0 13 0x8>, - <0 14 0x8>; - reg = <0xf0001000 0x1000>, - <0xf0002000 0x1000>; - }; - - frame@f0003000 { - frame-number = <1> - interrupts = <0 15 0x8>; - reg = <0xf0003000 0x1000>; - }; - }; diff --git a/Documentation/devicetree/bindings/timer/arm,arch_timer.yaml b/Documentation/devicetree/bindings/timer/arm,arch_timer.yaml new file mode 100644 index 000000000000..6deead07728e --- /dev/null +++ b/Documentation/devicetree/bindings/timer/arm,arch_timer.yaml @@ -0,0 +1,103 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/timer/arm,arch_timer.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: ARM architected timer + +maintainers: + - Marc Zyngier <marc.zyngier@arm.com> + - Mark Rutland <mark.rutland@arm.com> +description: |+ + ARM cores may have a per-core architected timer, which provides per-cpu timers, + or a memory mapped architected timer, which provides up to 8 frames with a + physical and optional virtual timer per frame. + + The per-core architected timer is attached to a GIC to deliver its + per-processor interrupts via PPIs. The memory mapped timer is attached to a GIC + to deliver its interrupts via SPIs. + +properties: + compatible: + oneOf: + - items: + - enum: + - arm,cortex-a15-timer + - enum: + - arm,armv7-timer + - items: + - enum: + - arm,armv7-timer + - items: + - enum: + - arm,armv8-timer + + interrupts: + items: + - description: secure timer irq + - description: non-secure timer irq + - description: virtual timer irq + - description: hypervisor timer irq + + clock-frequency: + description: The frequency of the main counter, in Hz. Should be present + only where necessary to work around broken firmware which does not configure + CNTFRQ on all CPUs to a uniform correct value. Use of this property is + strongly discouraged; fix your firmware unless absolutely impossible. + + always-on: + type: boolean + description: If present, the timer is powered through an always-on power + domain, therefore it never loses context. + + fsl,erratum-a008585: + type: boolean + description: Indicates the presence of QorIQ erratum A-008585, which says + that reading the counter is unreliable unless the same value is returned + by back-to-back reads. This also affects writes to the tval register, due + to the implicit counter read. + + hisilicon,erratum-161010101: + type: boolean + description: Indicates the presence of Hisilicon erratum 161010101, which + says that reading the counters is unreliable in some cases, and reads may + return a value 32 beyond the correct value. This also affects writes to + the tval registers, due to the implicit counter read. + + arm,cpu-registers-not-fw-configured: + type: boolean + description: Firmware does not initialize any of the generic timer CPU + registers, which contain their architecturally-defined reset values. Only + supported for 32-bit systems which follow the ARMv7 architected reset + values. + + arm,no-tick-in-suspend: + type: boolean + description: The main counter does not tick when the system is in + low-power system suspend on some SoCs. This behavior does not match the + Architecture Reference Manual's specification that the system counter "must + be implemented in an always-on power domain." + +required: + - compatible + +oneOf: + - required: + - interrupts + - required: + - interrupts-extended + +examples: + - | + timer { + compatible = "arm,cortex-a15-timer", + "arm,armv7-timer"; + interrupts = <1 13 0xf08>, + <1 14 0xf08>, + <1 11 0xf08>, + <1 10 0xf08>; + clock-frequency = <100000000>; + }; + +... diff --git a/Documentation/devicetree/bindings/timer/arm,arch_timer_mmio.yaml b/Documentation/devicetree/bindings/timer/arm,arch_timer_mmio.yaml new file mode 100644 index 000000000000..c4ab59550fc2 --- /dev/null +++ b/Documentation/devicetree/bindings/timer/arm,arch_timer_mmio.yaml @@ -0,0 +1,120 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/timer/arm,arch_timer_mmio.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: ARM memory mapped architected timer + +maintainers: + - Marc Zyngier <marc.zyngier@arm.com> + - Mark Rutland <mark.rutland@arm.com> + +description: |+ + ARM cores may have a memory mapped architected timer, which provides up to 8 + frames with a physical and optional virtual timer per frame. + + The memory mapped timer is attached to a GIC to deliver its interrupts via SPIs. + +properties: + compatible: + items: + - enum: + - arm,armv7-timer-mem + + reg: + maxItems: 1 + description: The control frame base address + + '#address-cells': + enum: [1, 2] + + '#size-cells': + const: 1 + + clock-frequency: + description: The frequency of the main counter, in Hz. Should be present + only where necessary to work around broken firmware which does not configure + CNTFRQ on all CPUs to a uniform correct value. Use of this property is + strongly discouraged; fix your firmware unless absolutely impossible. + + always-on: + type: boolean + description: If present, the timer is powered through an always-on power + domain, therefore it never loses context. + + arm,cpu-registers-not-fw-configured: + type: boolean + description: Firmware does not initialize any of the generic timer CPU + registers, which contain their architecturally-defined reset values. Only + supported for 32-bit systems which follow the ARMv7 architected reset + values. + + arm,no-tick-in-suspend: + type: boolean + description: The main counter does not tick when the system is in + low-power system suspend on some SoCs. This behavior does not match the + Architecture Reference Manual's specification that the system counter "must + be implemented in an always-on power domain." + +patternProperties: + '^frame@[0-9a-z]*$': + description: A timer node has up to 8 frame sub-nodes, each with the following properties. + properties: + frame-number: + allOf: + - $ref: "/schemas/types.yaml#/definitions/uint32" + - minimum: 0 + maximum: 7 + + interrupts: + minItems: 1 + maxItems: 2 + items: + - description: physical timer irq + - description: virtual timer irq + + reg : + minItems: 1 + maxItems: 2 + items: + - description: 1st view base address + - description: 2nd optional view base address + + required: + - frame-number + - interrupts + - reg + +required: + - compatible + - reg + - '#address-cells' + - '#size-cells' + +examples: + - | + timer@f0000000 { + compatible = "arm,armv7-timer-mem"; + #address-cells = <1>; + #size-cells = <1>; + ranges; + reg = <0xf0000000 0x1000>; + clock-frequency = <50000000>; + + frame@f0001000 { + frame-number = <0>; + interrupts = <0 13 0x8>, + <0 14 0x8>; + reg = <0xf0001000 0x1000>, + <0xf0002000 0x1000>; + }; + + frame@f0003000 { + frame-number = <1>; + interrupts = <0 15 0x8>; + reg = <0xf0003000 0x1000>; + }; + }; + +... diff --git a/Documentation/devicetree/bindings/timer/arm,global_timer.txt b/Documentation/devicetree/bindings/timer/arm,global_timer.txt deleted file mode 100644 index bdae3a818793..000000000000 --- a/Documentation/devicetree/bindings/timer/arm,global_timer.txt +++ /dev/null @@ -1,27 +0,0 @@ - -* ARM Global Timer - Cortex-A9 are often associated with a per-core Global timer. - -** Timer node required properties: - -- compatible : should contain - * "arm,cortex-a5-global-timer" for Cortex-A5 global timers. - * "arm,cortex-a9-global-timer" for Cortex-A9 global - timers or any compatible implementation. Note: driver - supports versions r2p0 and above. - -- interrupts : One interrupt to each core - -- reg : Specify the base address and the size of the GT timer - register window. - -- clocks : Should be phandle to a clock. - -Example: - - timer@2c000600 { - compatible = "arm,cortex-a9-global-timer"; - reg = <0x2c000600 0x20>; - interrupts = <1 13 0xf01>; - clocks = <&arm_periph_clk>; - }; diff --git a/Documentation/devicetree/bindings/timer/arm,global_timer.yaml b/Documentation/devicetree/bindings/timer/arm,global_timer.yaml new file mode 100644 index 000000000000..21c24a8e28fd --- /dev/null +++ b/Documentation/devicetree/bindings/timer/arm,global_timer.yaml @@ -0,0 +1,46 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/timer/arm,global_timer.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: ARM Global Timer + +maintainers: + - Stuart Menefy <stuart.menefy@st.com> + +description: + Cortex-A9 are often associated with a per-core Global timer. + +properties: + compatible: + items: + - enum: + - arm,cortex-a5-global-timer + - arm,cortex-a9-global-timer + + description: driver supports versions r2p0 and above. + + reg: + maxItems: 1 + + interrupts: + maxItems: 1 + + clocks: + maxItems: 1 + +required: + - compatible + - reg + - clocks + +examples: + - | + timer@2c000600 { + compatible = "arm,cortex-a9-global-timer"; + reg = <0x2c000600 0x20>; + interrupts = <1 13 0xf01>; + clocks = <&arm_periph_clk>; + }; +... diff --git a/Documentation/devicetree/bindings/timer/mrvl,mmp-timer.txt b/Documentation/devicetree/bindings/timer/mrvl,mmp-timer.txt index 9a6e251462e7..b8f02c663521 100644 --- a/Documentation/devicetree/bindings/timer/mrvl,mmp-timer.txt +++ b/Documentation/devicetree/bindings/timer/mrvl,mmp-timer.txt @@ -5,9 +5,13 @@ Required properties: - reg : Address and length of the register set of timer controller. - interrupts : Should be the interrupt number. +Optional properties: +- clocks : Should contain a single entry describing the clock input. + Example: timer0: timer@d4014000 { compatible = "mrvl,mmp-timer"; reg = <0xd4014000 0x100>; interrupts = <13>; + clocks = <&coreclk 2>; }; diff --git a/Documentation/devicetree/bindings/timer/rockchip,rk-timer.txt b/Documentation/devicetree/bindings/timer/rockchip,rk-timer.txt index 16a5f4577a61..d65fdce7c7f0 100644 --- a/Documentation/devicetree/bindings/timer/rockchip,rk-timer.txt +++ b/Documentation/devicetree/bindings/timer/rockchip,rk-timer.txt @@ -2,6 +2,7 @@ Rockchip rk timer Required properties: - compatible: should be: + "rockchip,rv1108-timer", "rockchip,rk3288-timer": for Rockchip RV1108 "rockchip,rk3036-timer", "rockchip,rk3288-timer": for Rockchip RK3036 "rockchip,rk3066-timer", "rockchip,rk3288-timer": for Rockchip RK3066 "rockchip,rk3188-timer", "rockchip,rk3288-timer": for Rockchip RK3188 diff --git a/Documentation/devicetree/bindings/trivial-devices.txt b/Documentation/devicetree/bindings/trivial-devices.txt deleted file mode 100644 index 6ab001fa1ed4..000000000000 --- a/Documentation/devicetree/bindings/trivial-devices.txt +++ /dev/null @@ -1,190 +0,0 @@ -This is a list of trivial i2c devices that have simple device tree -bindings, consisting only of a compatible field, an address and -possibly an interrupt line. - -If a device needs more specific bindings, such as properties to -describe some aspect of it, there needs to be a specific binding -document for it just like any other devices. - - -Compatible Vendor / Chip -========== ============= -abracon,abb5zes3 AB-RTCMC-32.768kHz-B5ZE-S3: Real Time Clock/Calendar Module with I2C Interface -ad,ad7414 SMBus/I2C Digital Temperature Sensor in 6-Pin SOT with SMBus Alert and Over Temperature Pin -ad,adm9240 ADM9240: Complete System Hardware Monitor for uProcessor-Based Systems -adi,adt7461 +/-1C TDM Extended Temp Range I.C -adt7461 +/-1C TDM Extended Temp Range I.C -adi,adt7473 +/-1C TDM Extended Temp Range I.C -adi,adt7475 +/-1C TDM Extended Temp Range I.C -adi,adt7476 +/-1C TDM Extended Temp Range I.C -adi,adt7490 +/-1C TDM Extended Temp Range I.C -adi,adxl345 Three-Axis Digital Accelerometer -adi,adxl346 Three-Axis Digital Accelerometer (backward-compatibility value "adi,adxl345" must be listed too) -ams,iaq-core AMS iAQ-Core VOC Sensor -at,24c08 i2c serial eeprom (24cxx) -atmel,at97sc3204t i2c trusted platform module (TPM) -capella,cm32181 CM32181: Ambient Light Sensor -capella,cm3232 CM3232: Ambient Light Sensor -dallas,ds1374 I2C, 32-Bit Binary Counter Watchdog RTC with Trickle Charger and Reset Input/Output -dallas,ds1631 High-Precision Digital Thermometer -dallas,ds1672 Dallas DS1672 Real-time Clock -dallas,ds1682 Total-Elapsed-Time Recorder with Alarm -dallas,ds1775 Tiny Digital Thermometer and Thermostat -dallas,ds3232 Extremely Accurate I²C RTC with Integrated Crystal and SRAM -dallas,ds4510 CPU Supervisor with Nonvolatile Memory and Programmable I/O -dallas,ds75 Digital Thermometer and Thermostat -devantech,srf02 Devantech SRF02 ultrasonic ranger in I2C mode -devantech,srf08 Devantech SRF08 ultrasonic ranger -devantech,srf10 Devantech SRF10 ultrasonic ranger -dlg,da9053 DA9053: flexible system level PMIC with multicore support -dlg,da9063 DA9063: system PMIC for quad-core application processors -domintech,dmard09 DMARD09: 3-axis Accelerometer -domintech,dmard10 DMARD10: 3-axis Accelerometer -epson,rx8010 I2C-BUS INTERFACE REAL TIME CLOCK MODULE -epson,rx8581 I2C-BUS INTERFACE REAL TIME CLOCK MODULE -emmicro,em3027 EM Microelectronic EM3027 Real-time Clock -fsl,mag3110 MAG3110: Xtrinsic High Accuracy, 3D Magnetometer -fsl,mma7660 MMA7660FC: 3-Axis Orientation/Motion Detection Sensor -fsl,mma8450 MMA8450Q: Xtrinsic Low-power, 3-axis Xtrinsic Accelerometer -fsl,mpl3115 MPL3115: Absolute Digital Pressure Sensor -fsl,mpr121 MPR121: Proximity Capacitive Touch Sensor Controller -fsl,sgtl5000 SGTL5000: Ultra Low-Power Audio Codec -gmt,g751 G751: Digital Temperature Sensor and Thermal Watchdog with Two-Wire Interface -infineon,slb9635tt Infineon SLB9635 (Soft-) I2C TPM (old protocol, max 100khz) -infineon,slb9645tt Infineon SLB9645 I2C TPM (new protocol, max 400khz) -infineon,tlv493d-a1b6 Infineon TLV493D-A1B6 I2C 3D Magnetic Sensor -isil,isl1208 Intersil ISL1208 Low Power RTC with Battery Backed SRAM -isil,isl1218 Intersil ISL1218 Low Power RTC with Battery Backed SRAM -isil,isl12022 Intersil ISL12022 Real-time Clock -isil,isl29028 Intersil ISL29028 Ambient Light and Proximity Sensor -isil,isl29030 Intersil ISL29030 Ambient Light and Proximity Sensor -maxim,ds1050 5 Bit Programmable, Pulse-Width Modulator -maxim,max1237 Low-Power, 4-/12-Channel, 2-Wire Serial, 12-Bit ADCs -maxim,max6621 PECI-to-I2C translator for PECI-to-SMBus/I2C protocol conversion -maxim,max6625 9-Bit/12-Bit Temperature Sensors with I²C-Compatible Serial Interface -mcube,mc3230 mCube 3-axis 8-bit digital accelerometer -memsic,mxc6225 MEMSIC 2-axis 8-bit digital accelerometer -microchip,mcp4017-502 Microchip 7-bit Single I2C Digital POT (5k) -microchip,mcp4017-103 Microchip 7-bit Single I2C Digital POT (10k) -microchip,mcp4017-503 Microchip 7-bit Single I2C Digital POT (50k) -microchip,mcp4017-104 Microchip 7-bit Single I2C Digital POT (100k) -microchip,mcp4018-502 Microchip 7-bit Single I2C Digital POT (5k) -microchip,mcp4018-103 Microchip 7-bit Single I2C Digital POT (10k) -microchip,mcp4018-503 Microchip 7-bit Single I2C Digital POT (50k) -microchip,mcp4018-104 Microchip 7-bit Single I2C Digital POT (100k) -microchip,mcp4019-502 Microchip 7-bit Single I2C Digital POT (5k) -microchip,mcp4019-103 Microchip 7-bit Single I2C Digital POT (10k) -microchip,mcp4019-503 Microchip 7-bit Single I2C Digital POT (50k) -microchip,mcp4019-104 Microchip 7-bit Single I2C Digital POT (100k) -microchip,mcp4531-502 Microchip 7-bit Single I2C Digital Potentiometer (5k) -microchip,mcp4531-103 Microchip 7-bit Single I2C Digital Potentiometer (10k) -microchip,mcp4531-503 Microchip 7-bit Single I2C Digital Potentiometer (50k) -microchip,mcp4531-104 Microchip 7-bit Single I2C Digital Potentiometer (100k) -microchip,mcp4532-502 Microchip 7-bit Single I2C Digital Potentiometer (5k) -microchip,mcp4532-103 Microchip 7-bit Single I2C Digital Potentiometer (10k) -microchip,mcp4532-503 Microchip 7-bit Single I2C Digital Potentiometer (50k) -microchip,mcp4532-104 Microchip 7-bit Single I2C Digital Potentiometer (100k) -microchip,mcp4541-502 Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (5k) -microchip,mcp4541-103 Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (10k) -microchip,mcp4541-503 Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (50k) -microchip,mcp4541-104 Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (100k) -microchip,mcp4542-502 Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (5k) -microchip,mcp4542-103 Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (10k) -microchip,mcp4542-503 Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (50k) -microchip,mcp4542-104 Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (100k) -microchip,mcp4551-502 Microchip 8-bit Single I2C Digital Potentiometer (5k) -microchip,mcp4551-103 Microchip 8-bit Single I2C Digital Potentiometer (10k) -microchip,mcp4551-503 Microchip 8-bit Single I2C Digital Potentiometer (50k) -microchip,mcp4551-104 Microchip 8-bit Single I2C Digital Potentiometer (100k) -microchip,mcp4552-502 Microchip 8-bit Single I2C Digital Potentiometer (5k) -microchip,mcp4552-103 Microchip 8-bit Single I2C Digital Potentiometer (10k) -microchip,mcp4552-503 Microchip 8-bit Single I2C Digital Potentiometer (50k) -microchip,mcp4552-104 Microchip 8-bit Single I2C Digital Potentiometer (100k) -microchip,mcp4561-502 Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (5k) -microchip,mcp4561-103 Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (10k) -microchip,mcp4561-503 Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (50k) -microchip,mcp4561-104 Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (100k) -microchip,mcp4562-502 Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (5k) -microchip,mcp4562-103 Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (10k) -microchip,mcp4562-503 Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (50k) -microchip,mcp4562-104 Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (100k) -microchip,mcp4631-502 Microchip 7-bit Dual I2C Digital Potentiometer (5k) -microchip,mcp4631-103 Microchip 7-bit Dual I2C Digital Potentiometer (10k) -microchip,mcp4631-503 Microchip 7-bit Dual I2C Digital Potentiometer (50k) -microchip,mcp4631-104 Microchip 7-bit Dual I2C Digital Potentiometer (100k) -microchip,mcp4632-502 Microchip 7-bit Dual I2C Digital Potentiometer (5k) -microchip,mcp4632-103 Microchip 7-bit Dual I2C Digital Potentiometer (10k) -microchip,mcp4632-503 Microchip 7-bit Dual I2C Digital Potentiometer (50k) -microchip,mcp4632-104 Microchip 7-bit Dual I2C Digital Potentiometer (100k) -microchip,mcp4641-502 Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (5k) -microchip,mcp4641-103 Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (10k) -microchip,mcp4641-503 Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (50k) -microchip,mcp4641-104 Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (100k) -microchip,mcp4642-502 Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (5k) -microchip,mcp4642-103 Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (10k) -microchip,mcp4642-503 Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (50k) -microchip,mcp4642-104 Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (100k) -microchip,mcp4651-502 Microchip 8-bit Dual I2C Digital Potentiometer (5k) -microchip,mcp4651-103 Microchip 8-bit Dual I2C Digital Potentiometer (10k) -microchip,mcp4651-503 Microchip 8-bit Dual I2C Digital Potentiometer (50k) -microchip,mcp4651-104 Microchip 8-bit Dual I2C Digital Potentiometer (100k) -microchip,mcp4652-502 Microchip 8-bit Dual I2C Digital Potentiometer (5k) -microchip,mcp4652-103 Microchip 8-bit Dual I2C Digital Potentiometer (10k) -microchip,mcp4652-503 Microchip 8-bit Dual I2C Digital Potentiometer (50k) -microchip,mcp4652-104 Microchip 8-bit Dual I2C Digital Potentiometer (100k) -microchip,mcp4661-502 Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (5k) -microchip,mcp4661-103 Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (10k) -microchip,mcp4661-503 Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (50k) -microchip,mcp4661-104 Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (100k) -microchip,mcp4662-502 Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (5k) -microchip,mcp4662-103 Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (10k) -microchip,mcp4662-503 Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (50k) -microchip,mcp4662-104 Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (100k) -microchip,tc654 PWM Fan Speed Controller With Fan Fault Detection -microchip,tc655 PWM Fan Speed Controller With Fan Fault Detection -microcrystal,rv3029 Real Time Clock Module with I2C-Bus -miramems,da226 MiraMEMS DA226 2-axis 14-bit digital accelerometer -miramems,da280 MiraMEMS DA280 3-axis 14-bit digital accelerometer -miramems,da311 MiraMEMS DA311 3-axis 12-bit digital accelerometer -national,lm63 Temperature sensor with integrated fan control -national,lm75 I2C TEMP SENSOR -national,lm80 Serial Interface ACPI-Compatible Microprocessor System Hardware Monitor -national,lm85 Temperature sensor with integrated fan control -national,lm92 ±0.33°C Accurate, 12-Bit + Sign Temperature Sensor and Thermal Window Comparator with Two-Wire Interface -nuvoton,npct501 i2c trusted platform module (TPM) -nuvoton,npct601 i2c trusted platform module (TPM2) -nuvoton,w83773g Nuvoton Temperature Sensor -nxp,pca9556 Octal SMBus and I2C registered interface -nxp,pca9557 8-bit I2C-bus and SMBus I/O port with reset -nxp,pcf2127 Real-time clock -nxp,pcf2129 Real-time clock -nxp,pcf8523 Real-time Clock -nxp,pcf8563 Real-time clock/calendar -nxp,pcf85063 Tiny Real-Time Clock -oki,ml86v7667 OKI ML86V7667 video decoder -ovti,ov5642 OV5642: Color CMOS QSXGA (5-megapixel) Image Sensor with OmniBSI and Embedded TrueFocus -pericom,pt7c4338 Real-time Clock Module -plx,pex8648 48-Lane, 12-Port PCI Express Gen 2 (5.0 GT/s) Switch -pulsedlight,lidar-lite-v2 Pulsedlight LIDAR range-finding sensor -ricoh,r2025sd I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC -ricoh,r2221tl I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC -ricoh,rs5c372a I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC -ricoh,rs5c372b I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC -ricoh,rv5c386 I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC -ricoh,rv5c387a I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC -samsung,24ad0xd1 S524AD0XF1 (128K/256K-bit Serial EEPROM for Low Power) -sgx,vz89x SGX Sensortech VZ89X Sensors -sii,s35390a 2-wire CMOS real-time clock -silabs,si7020 Relative Humidity and Temperature Sensors -skyworks,sky81452 Skyworks SKY81452: Six-Channel White LED Driver with Touch Panel Bias Supply -st,24c256 i2c serial eeprom (24cxx) -taos,tsl2550 Ambient Light Sensor with SMBUS/Two Wire Serial Interface -ti,ads7828 8-Channels, 12-bit ADC -ti,ads7830 8-Channels, 8-bit ADC -ti,amc6821 Temperature Monitoring and Fan Control -ti,tsc2003 I2C Touch-Screen Controller -ti,tmp102 Low Power Digital Temperature Sensor with SMBUS/Two Wire Serial Interface -ti,tmp103 Low Power Digital Temperature Sensor with SMBUS/Two Wire Serial Interface -ti,tmp275 Digital Temperature Sensor -winbond,w83793 Winbond/Nuvoton H/W Monitor -winbond,wpct301 i2c trusted platform module (TPM) diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml new file mode 100644 index 000000000000..cc64ec63a6ad --- /dev/null +++ b/Documentation/devicetree/bindings/trivial-devices.yaml @@ -0,0 +1,342 @@ +# SPDX-License-Identifier: GPL-2.0 +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/trivial-devices.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Trivial I2C and SPI devices that have simple device tree bindings + +maintainers: + - Rob Herring <robh@kernel.org> + +description: | + This is a list of trivial I2C and SPI devices that have simple device tree + bindings, consisting only of a compatible field, an address and possibly an + interrupt line. + + If a device needs more specific bindings, such as properties to + describe some aspect of it, there needs to be a specific binding + document for it just like any other devices. + +properties: + reg: + maxItems: 1 + interrupts: + maxItems: 1 + compatible: + items: + - enum: + # SMBus/I2C Digital Temperature Sensor in 6-Pin SOT with SMBus Alert and Over Temperature Pin + - ad,ad7414 + # ADM9240: Complete System Hardware Monitor for uProcessor-Based Systems + - ad,adm9240 + # +/-1C TDM Extended Temp Range I.C + - adi,adt7461 + # +/-1C TDM Extended Temp Range I.C + - adt7461 + # +/-1C TDM Extended Temp Range I.C + - adi,adt7473 + # +/-1C TDM Extended Temp Range I.C + - adi,adt7475 + # +/-1C TDM Extended Temp Range I.C + - adi,adt7476 + # +/-1C TDM Extended Temp Range I.C + - adi,adt7490 + # Three-Axis Digital Accelerometer + - adi,adxl345 + # Three-Axis Digital Accelerometer (backward-compatibility value "adi,adxl345" must be listed too) + - adi,adxl346 + # AMS iAQ-Core VOC Sensor + - ams,iaq-core + # i2c serial eeprom (24cxx) + - at,24c08 + # i2c trusted platform module (TPM) + - atmel,at97sc3204t + # CM32181: Ambient Light Sensor + - capella,cm32181 + # CM3232: Ambient Light Sensor + - capella,cm3232 + # High-Precision Digital Thermometer + - dallas,ds1631 + # Total-Elapsed-Time Recorder with Alarm + - dallas,ds1682 + # Tiny Digital Thermometer and Thermostat + - dallas,ds1775 + # CPU Supervisor with Nonvolatile Memory and Programmable I/O + - dallas,ds4510 + # Digital Thermometer and Thermostat + - dallas,ds75 + # Devantech SRF02 ultrasonic ranger in I2C mode + - devantech,srf02 + # Devantech SRF08 ultrasonic ranger + - devantech,srf08 + # Devantech SRF10 ultrasonic ranger + - devantech,srf10 + # DA9053: flexible system level PMIC with multicore support + - dlg,da9053 + # DA9063: system PMIC for quad-core application processors + - dlg,da9063 + # DMARD09: 3-axis Accelerometer + - domintech,dmard09 + # DMARD10: 3-axis Accelerometer + - domintech,dmard10 + # MMA7660FC: 3-Axis Orientation/Motion Detection Sensor + - fsl,mma7660 + # MMA8450Q: Xtrinsic Low-power, 3-axis Xtrinsic Accelerometer + - fsl,mma8450 + # MPL3115: Absolute Digital Pressure Sensor + - fsl,mpl3115 + # MPR121: Proximity Capacitive Touch Sensor Controller + - fsl,mpr121 + # SGTL5000: Ultra Low-Power Audio Codec + - fsl,sgtl5000 + # G751: Digital Temperature Sensor and Thermal Watchdog with Two-Wire Interface + - gmt,g751 + # Infineon SLB9635 (Soft-) I2C TPM (old protocol, max 100khz) + - infineon,slb9635tt + # Infineon SLB9645 I2C TPM (new protocol, max 400khz) + - infineon,slb9645tt + # Infineon TLV493D-A1B6 I2C 3D Magnetic Sensor + - infineon,tlv493d-a1b6 + # Intersil ISL29028 Ambient Light and Proximity Sensor + - isil,isl29028 + # Intersil ISL29030 Ambient Light and Proximity Sensor + - isil,isl29030 + # 5 Bit Programmable, Pulse-Width Modulator + - maxim,ds1050 + # Low-Power, 4-/12-Channel, 2-Wire Serial, 12-Bit ADCs + - maxim,max1237 + # PECI-to-I2C translator for PECI-to-SMBus/I2C protocol conversion + - maxim,max6621 + # 9-Bit/12-Bit Temperature Sensors with I²C-Compatible Serial Interface + - maxim,max6625 + # mCube 3-axis 8-bit digital accelerometer + - mcube,mc3230 + # MEMSIC 2-axis 8-bit digital accelerometer + - memsic,mxc6225 + # Microchip 7-bit Single I2C Digital POT (5k) + - microchip,mcp4017-502 + # Microchip 7-bit Single I2C Digital POT (10k) + - microchip,mcp4017-103 + # Microchip 7-bit Single I2C Digital POT (50k) + - microchip,mcp4017-503 + # Microchip 7-bit Single I2C Digital POT (100k) + - microchip,mcp4017-104 + # Microchip 7-bit Single I2C Digital POT (5k) + - microchip,mcp4018-502 + # Microchip 7-bit Single I2C Digital POT (10k) + - microchip,mcp4018-103 + # Microchip 7-bit Single I2C Digital POT (50k) + - microchip,mcp4018-503 + # Microchip 7-bit Single I2C Digital POT (100k) + - microchip,mcp4018-104 + # Microchip 7-bit Single I2C Digital POT (5k) + - microchip,mcp4019-502 + # Microchip 7-bit Single I2C Digital POT (10k) + - microchip,mcp4019-103 + # Microchip 7-bit Single I2C Digital POT (50k) + - microchip,mcp4019-503 + # Microchip 7-bit Single I2C Digital POT (100k) + - microchip,mcp4019-104 + # Microchip 7-bit Single I2C Digital Potentiometer (5k) + - microchip,mcp4531-502 + # Microchip 7-bit Single I2C Digital Potentiometer (10k) + - microchip,mcp4531-103 + # Microchip 7-bit Single I2C Digital Potentiometer (50k) + - microchip,mcp4531-503 + # Microchip 7-bit Single I2C Digital Potentiometer (100k) + - microchip,mcp4531-104 + # Microchip 7-bit Single I2C Digital Potentiometer (5k) + - microchip,mcp4532-502 + # Microchip 7-bit Single I2C Digital Potentiometer (10k) + - microchip,mcp4532-103 + # Microchip 7-bit Single I2C Digital Potentiometer (50k) + - microchip,mcp4532-503 + # Microchip 7-bit Single I2C Digital Potentiometer (100k) + - microchip,mcp4532-104 + # Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (5k) + - microchip,mcp4541-502 + # Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (10k) + - microchip,mcp4541-103 + # Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (50k) + - microchip,mcp4541-503 + # Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (100k) + - microchip,mcp4541-104 + # Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (5k) + - microchip,mcp4542-502 + # Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (10k) + - microchip,mcp4542-103 + # Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (50k) + - microchip,mcp4542-503 + # Microchip 7-bit Single I2C Digital Potentiometer with NV Memory (100k) + - microchip,mcp4542-104 + # Microchip 8-bit Single I2C Digital Potentiometer (5k) + - microchip,mcp4551-502 + # Microchip 8-bit Single I2C Digital Potentiometer (10k) + - microchip,mcp4551-103 + # Microchip 8-bit Single I2C Digital Potentiometer (50k) + - microchip,mcp4551-503 + # Microchip 8-bit Single I2C Digital Potentiometer (100k) + - microchip,mcp4551-104 + # Microchip 8-bit Single I2C Digital Potentiometer (5k) + - microchip,mcp4552-502 + # Microchip 8-bit Single I2C Digital Potentiometer (10k) + - microchip,mcp4552-103 + # Microchip 8-bit Single I2C Digital Potentiometer (50k) + - microchip,mcp4552-503 + # Microchip 8-bit Single I2C Digital Potentiometer (100k) + - microchip,mcp4552-104 + # Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (5k) + - microchip,mcp4561-502 + # Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (10k) + - microchip,mcp4561-103 + # Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (50k) + - microchip,mcp4561-503 + # Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (100k) + - microchip,mcp4561-104 + # Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (5k) + - microchip,mcp4562-502 + # Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (10k) + - microchip,mcp4562-103 + # Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (50k) + - microchip,mcp4562-503 + # Microchip 8-bit Single I2C Digital Potentiometer with NV Memory (100k) + - microchip,mcp4562-104 + # Microchip 7-bit Dual I2C Digital Potentiometer (5k) + - microchip,mcp4631-502 + # Microchip 7-bit Dual I2C Digital Potentiometer (10k) + - microchip,mcp4631-103 + # Microchip 7-bit Dual I2C Digital Potentiometer (50k) + - microchip,mcp4631-503 + # Microchip 7-bit Dual I2C Digital Potentiometer (100k) + - microchip,mcp4631-104 + # Microchip 7-bit Dual I2C Digital Potentiometer (5k) + - microchip,mcp4632-502 + # Microchip 7-bit Dual I2C Digital Potentiometer (10k) + - microchip,mcp4632-103 + # Microchip 7-bit Dual I2C Digital Potentiometer (50k) + - microchip,mcp4632-503 + # Microchip 7-bit Dual I2C Digital Potentiometer (100k) + - microchip,mcp4632-104 + # Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (5k) + - microchip,mcp4641-502 + # Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (10k) + - microchip,mcp4641-103 + # Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (50k) + - microchip,mcp4641-503 + # Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (100k) + - microchip,mcp4641-104 + # Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (5k) + - microchip,mcp4642-502 + # Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (10k) + - microchip,mcp4642-103 + # Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (50k) + - microchip,mcp4642-503 + # Microchip 7-bit Dual I2C Digital Potentiometer with NV Memory (100k) + - microchip,mcp4642-104 + # Microchip 8-bit Dual I2C Digital Potentiometer (5k) + - microchip,mcp4651-502 + # Microchip 8-bit Dual I2C Digital Potentiometer (10k) + - microchip,mcp4651-103 + # Microchip 8-bit Dual I2C Digital Potentiometer (50k) + - microchip,mcp4651-503 + # Microchip 8-bit Dual I2C Digital Potentiometer (100k) + - microchip,mcp4651-104 + # Microchip 8-bit Dual I2C Digital Potentiometer (5k) + - microchip,mcp4652-502 + # Microchip 8-bit Dual I2C Digital Potentiometer (10k) + - microchip,mcp4652-103 + # Microchip 8-bit Dual I2C Digital Potentiometer (50k) + - microchip,mcp4652-503 + # Microchip 8-bit Dual I2C Digital Potentiometer (100k) + - microchip,mcp4652-104 + # Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (5k) + - microchip,mcp4661-502 + # Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (10k) + - microchip,mcp4661-103 + # Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (50k) + - microchip,mcp4661-503 + # Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (100k) + - microchip,mcp4661-104 + # Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (5k) + - microchip,mcp4662-502 + # Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (10k) + - microchip,mcp4662-103 + # Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (50k) + - microchip,mcp4662-503 + # Microchip 8-bit Dual I2C Digital Potentiometer with NV Memory (100k) + - microchip,mcp4662-104 + # PWM Fan Speed Controller With Fan Fault Detection + - microchip,tc654 + # PWM Fan Speed Controller With Fan Fault Detection + - microchip,tc655 + # MiraMEMS DA226 2-axis 14-bit digital accelerometer + - miramems,da226 + # MiraMEMS DA280 3-axis 14-bit digital accelerometer + - miramems,da280 + # MiraMEMS DA311 3-axis 12-bit digital accelerometer + - miramems,da311 + # Temperature sensor with integrated fan control + - national,lm63 + # I2C TEMP SENSOR + - national,lm75 + # Serial Interface ACPI-Compatible Microprocessor System Hardware Monitor + - national,lm80 + # Temperature sensor with integrated fan control + - national,lm85 + # ±0.33°C Accurate, 12-Bit + Sign Temperature Sensor and Thermal Window Comparator with Two-Wire Interface + - national,lm92 + # i2c trusted platform module (TPM) + - nuvoton,npct501 + # i2c trusted platform module (TPM2) + - nuvoton,npct601 + # Nuvoton Temperature Sensor + - nuvoton,w83773g + # Octal SMBus and I2C registered interface + - nxp,pca9556 + # 8-bit I2C-bus and SMBus I/O port with reset + - nxp,pca9557 + # OKI ML86V7667 video decoder + - oki,ml86v7667 + # OV5642: Color CMOS QSXGA (5-megapixel) Image Sensor with OmniBSI and Embedded TrueFocus + - ovti,ov5642 + # 48-Lane, 12-Port PCI Express Gen 2 (5.0 GT/s) Switch + - plx,pex8648 + # Pulsedlight LIDAR range-finding sensor + - pulsedlight,lidar-lite-v2 + # S524AD0XF1 (128K/256K-bit Serial EEPROM for Low Power) + - samsung,24ad0xd1 + # SGX Sensortech VZ89X Sensors + - sgx,vz89x + # Relative Humidity and Temperature Sensors + - silabs,si7020 + # Skyworks SKY81452: Six-Channel White LED Driver with Touch Panel Bias Supply + - skyworks,sky81452 + # i2c serial eeprom (24cxx) + - st,24c256 + # Ambient Light Sensor with SMBUS/Two Wire Serial Interface + - taos,tsl2550 + # 8-Channels, 12-bit ADC + - ti,ads7828 + # 8-Channels, 8-bit ADC + - ti,ads7830 + # Temperature Monitoring and Fan Control + - ti,amc6821 + # I2C Touch-Screen Controller + - ti,tsc2003 + # Low Power Digital Temperature Sensor with SMBUS/Two Wire Serial Interface + - ti,tmp102 + # Low Power Digital Temperature Sensor with SMBUS/Two Wire Serial Interface + - ti,tmp103 + # Digital Temperature Sensor + - ti,tmp275 + # Winbond/Nuvoton H/W Monitor + - winbond,w83793 + # i2c trusted platform module (TPM) + - winbond,wpct301 + +required: + - compatible + - reg + +... diff --git a/Documentation/devicetree/bindings/ufs/cdns,ufshc.txt b/Documentation/devicetree/bindings/ufs/cdns,ufshc.txt new file mode 100644 index 000000000000..a04a4989ec7f --- /dev/null +++ b/Documentation/devicetree/bindings/ufs/cdns,ufshc.txt @@ -0,0 +1,31 @@ +* Cadence Universal Flash Storage (UFS) Controller + +UFS nodes are defined to describe on-chip UFS host controllers. +Each UFS controller instance should have its own node. +Please see the ufshcd-pltfrm.txt for a list of all available properties. + +Required properties: +- compatible : Compatible list, contains the following controller: + "cdns,ufshc" + complemented with the JEDEC version: + "jedec,ufs-2.0" + +- reg : Address and length of the UFS register set. +- interrupts : One interrupt mapping. +- freq-table-hz : Clock frequency table. + See the ufshcd-pltfrm.txt for details. +- clocks : List of phandle and clock specifier pairs. +- clock-names : List of clock input name strings sorted in the same + order as the clocks property. "core_clk" is mandatory. + Depending on a type of a PHY, + the "phy_clk" clock can also be added, if needed. + +Example: + ufs@fd030000 { + compatible = "cdns,ufshc", "jedec,ufs-2.0"; + reg = <0xfd030000 0x10000>; + interrupts = <0 1 IRQ_TYPE_LEVEL_HIGH>; + freq-table-hz = <0 0>, <0 0>; + clocks = <&ufs_core_clk>, <&ufs_phy_clk>; + clock-names = "core_clk", "phy_clk"; + }; diff --git a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt index 2df00524bd21..8cf59452c675 100644 --- a/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt +++ b/Documentation/devicetree/bindings/ufs/ufshcd-pltfrm.txt @@ -33,6 +33,12 @@ Optional properties: - clocks : List of phandle and clock specifier pairs - clock-names : List of clock input name strings sorted in the same order as the clocks property. + "ref_clk" indicates reference clock frequency. + UFS host supplies reference clock to UFS device and UFS device + specification allows host to provide one of the 4 frequencies (19.2 MHz, + 26 MHz, 38.4 MHz, 52MHz) for reference clock. This "ref_clk" entry is + parsed and used to update the reference clock setting in device. + Defaults to 26 MHz(as per specification) if not specified by host. - freq-table-hz : Array of <min max> operating frequencies stored in the same order as the clocks property. If this property is not defined or a value in the array is "0" then it is assumed diff --git a/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt b/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt index 529e51879fb2..adae82385dd6 100644 --- a/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt +++ b/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt @@ -80,15 +80,19 @@ Optional properties: controller. It's expected that a mux state of 0 indicates device mode and a mux state of 1 indicates host mode. - mux-control-names: Shall be "usb_switch" if mux-controls is specified. -- pinctrl-names: Names for optional pin modes in "default", "host", "device" +- pinctrl-names: Names for optional pin modes in "default", "host", "device". + In case of HSIC-mode, "idle" and "active" pin modes are mandatory. In this + case, the "idle" state needs to pull down the data and strobe pin + and the "active" state needs to pull up the strobe pin. - pinctrl-n: alternate pin modes i.mx specific properties - fsl,usbmisc: phandler of non-core register device, with one argument that indicate usb controller index - disable-over-current: disable over current detect -- over-current-active-high: over current signal polarity is high active, - typically over current signal polarity is low active. +- over-current-active-low: over current signal polarity is active low. +- over-current-active-high: over current signal polarity is active high. + It's recommended to specify the over current polarity. - external-vbus-divider: enables off-chip resistor divider for Vbus Example: @@ -111,3 +115,29 @@ Example: mux-controls = <&usb_switch>; mux-control-names = "usb_switch"; }; + +Example for HSIC: + + usb@2184400 { + compatible = "fsl,imx6q-usb", "fsl,imx27-usb"; + reg = <0x02184400 0x200>; + interrupts = <0 41 IRQ_TYPE_LEVEL_HIGH>; + clocks = <&clks IMX6QDL_CLK_USBOH3>; + fsl,usbphy = <&usbphynop1>; + fsl,usbmisc = <&usbmisc 2>; + phy_type = "hsic"; + dr_mode = "host"; + ahb-burst-config = <0x0>; + tx-burst-size-dword = <0x10>; + rx-burst-size-dword = <0x10>; + pinctrl-names = "idle", "active"; + pinctrl-0 = <&pinctrl_usbh2_idle>; + pinctrl-1 = <&pinctrl_usbh2_active>; + #address-cells = <1>; + #size-cells = <0>; + + usbnet: smsc@1 { + compatible = "usb424,9730"; + reg = <1>; + }; + }; diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt index 636630fb92d7..8e5265e9f658 100644 --- a/Documentation/devicetree/bindings/usb/dwc3.txt +++ b/Documentation/devicetree/bindings/usb/dwc3.txt @@ -37,7 +37,11 @@ Optional properties: - phy-names: from the *Generic PHY* bindings; supported names are "usb2-phy" or "usb3-phy". - resets: a single pair of phandle and reset specifier + - snps,usb2-lpm-disable: indicate if we don't want to enable USB2 HW LPM - snps,usb3_lpm_capable: determines if platform is USB3 LPM capable + - snps,dis-start-transfer-quirk: when set, disable isoc START TRANSFER command + failure SW work-around for DWC_usb31 version 1.70a-ea06 + and prior. - snps,disable_scramble_quirk: true when SW should disable data scrambling. Only really useful for FPGA builds. - snps,has-lpm-erratum: true when DWC3 was configured with LPM Erratum enabled diff --git a/Documentation/devicetree/bindings/usb/nvidia,tegra124-xusb.txt b/Documentation/devicetree/bindings/usb/nvidia,tegra124-xusb.txt index 3eee9e505400..4156c3e181c5 100644 --- a/Documentation/devicetree/bindings/usb/nvidia,tegra124-xusb.txt +++ b/Documentation/devicetree/bindings/usb/nvidia,tegra124-xusb.txt @@ -59,6 +59,14 @@ For Tegra210: - avdd-pll-uerefe-supply: PLLE reference PLL power supply. Must supply 1.05 V. - dvdd-pex-pll-supply: PCIe/USB3 PLL power supply. Must supply 1.05 V. - hvdd-pex-pll-e-supply: High-voltage PLLE power supply. Must supply 1.8 V. +- power-domains: A list of PM domain specifiers that reference each power-domain + used by the xHCI controller. This list must comprise of a specifier for the + XUSBA and XUSBC power-domains. See ../power/power_domain.txt and + ../arm/tegra/nvidia,tegra20-pmc.txt for details. +- power-domain-names: A list of names that represent each of the specifiers in + the 'power-domains' property. Must include 'xusb_ss' and 'xusb_host' which + represent the power-domains XUSBA and XUSBC, respectively. See + ../power/power_domain.txt for details. Optional properties: -------------------- diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt index a2f4451cf3f9..3bbe3b87a1ff 100644 --- a/Documentation/devicetree/bindings/vendor-prefixes.txt +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt @@ -114,6 +114,7 @@ edt Emerging Display Technologies eeti eGalax_eMPIA Technology Inc elan Elan Microelectronic Corp. embest Shenzhen Embest Technology Co., Ltd. +emlid Emlid, Ltd. emmicro EM Microelectronic emtrion emtrion GmbH endless Endless Mobile, Inc. @@ -171,6 +172,7 @@ holtek Holtek Semiconductor, Inc. hwacom HwaCom Systems Inc. i2se I2SE GmbH ibm International Business Machines (IBM) +icplus IC Plus Corp. idt Integrated Device Technologies, Inc. ifi Ingenieurburo Fur Ic-Technologie (I/F/I) ilitek ILI Technology Corporation (ILITEK) @@ -297,6 +299,7 @@ panasonic Panasonic Corporation parade Parade Technologies Inc. pericom Pericom Technology Inc. pervasive Pervasive Displays, Inc. +phicomm PHICOMM Co., Ltd. phytec PHYTEC Messtechnik GmbH picochip Picochip Ltd pine64 Pine64 @@ -304,6 +307,7 @@ pixcir PIXCIR MICROELECTRONICS Co., Ltd plathome Plat'Home Co., Ltd. plda PLDA plx Broadcom Corporation (formerly PLX Technology) +pni PNI Sensor Corporation portwell Portwell Inc. poslab Poslab Technology Co., Ltd. powervr PowerVR (deprecated, use img) @@ -416,6 +420,7 @@ vamrs Vamrs Ltd. variscite Variscite Ltd. via VIA Technologies, Inc. virtio Virtual I/O Device Specification, developed by the OASIS consortium +vishay Vishay Intertechnology, Inc vitesse Vitesse Semiconductor Corporation vivante Vivante Corporation vocore VoCore Studio diff --git a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt index 859dee167b91..8682d6a93e5b 100644 --- a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt +++ b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt @@ -8,6 +8,7 @@ Required properties: "mediatek,mt6797-wdt", "mediatek,mt6589-wdt": for MT6797 "mediatek,mt7622-wdt", "mediatek,mt6589-wdt": for MT7622 "mediatek,mt7623-wdt", "mediatek,mt6589-wdt": for MT7623 + "mediatek,mt7629-wdt", "mediatek,mt6589-wdt": for MT7629 - reg : Specifies base physical address and size of the registers. diff --git a/Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt b/Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt new file mode 100644 index 000000000000..6fb984f31982 --- /dev/null +++ b/Documentation/devicetree/bindings/watchdog/qcom,pm8916-wdt.txt @@ -0,0 +1,28 @@ +QCOM PM8916 watchdog timer controller + +This pm8916 watchdog timer controller must be under pm8916-pon node. + +Required properties: +- compatible: should be "qcom,pm8916-wdt" + +Optional properties : +- interrupts : Watchdog pre-timeout (bark) interrupt. +- timeout-sec : Watchdog timeout value in seconds. + +Example: + + pm8916_0: pm8916@0 { + compatible = "qcom,pm8916", "qcom,spmi-pmic"; + reg = <0x0 SPMI_USID>; + + pon@800 { + compatible = "qcom,pm8916-pon"; + reg = <0x800>; + + watchdog { + compatible = "qcom,pm8916-wdt"; + interrupts = <0x0 0x8 6 IRQ_TYPE_EDGE_RISING>; + timeout-sec = <10>; + }; + }; + }; diff --git a/Documentation/devicetree/bindings/watchdog/renesas-wdt.txt b/Documentation/devicetree/bindings/watchdog/renesas-wdt.txt index a8ee29fd9ac8..ef2b97b72e08 100644 --- a/Documentation/devicetree/bindings/watchdog/renesas-wdt.txt +++ b/Documentation/devicetree/bindings/watchdog/renesas-wdt.txt @@ -9,6 +9,7 @@ Required properties: - "renesas,r8a7744-wdt" (RZ/G1N) - "renesas,r8a7745-wdt" (RZ/G1E) - "renesas,r8a774a1-wdt" (RZ/G2M) + - "renesas,r8a774c0-wdt" (RZ/G2E) - "renesas,r8a7790-wdt" (R-Car H2) - "renesas,r8a7791-wdt" (R-Car M2-W) - "renesas,r8a7792-wdt" (R-Car V2H) diff --git a/Documentation/devicetree/bindings/watchdog/sunxi-wdt.txt b/Documentation/devicetree/bindings/watchdog/sunxi-wdt.txt index ed11ce0ac836..46055254e8dd 100644 --- a/Documentation/devicetree/bindings/watchdog/sunxi-wdt.txt +++ b/Documentation/devicetree/bindings/watchdog/sunxi-wdt.txt @@ -6,6 +6,7 @@ Required properties: "allwinner,sun4i-a10-wdt" "allwinner,sun6i-a31-wdt" "allwinner,sun50i-a64-wdt","allwinner,sun6i-a31-wdt" + "allwinner,suniv-f1c100s-wdt", "allwinner,sun4i-a10-wdt" - reg : Specifies base physical address and size of the registers. Optional properties: diff --git a/Documentation/devicetree/todo.txt b/Documentation/devicetree/todo.txt deleted file mode 100644 index b5139d1de811..000000000000 --- a/Documentation/devicetree/todo.txt +++ /dev/null @@ -1,10 +0,0 @@ -Todo list for devicetree: - -=== General structure === -- Switch from custom lists to (h)list_head for nodes and properties structure - -=== CONFIG_OF_DYNAMIC === -- Switch to RCU for tree updates and get rid of global spinlock -- Document node lifecycle for CONFIG_OF_DYNAMIC -- Always set ->full_name at of_attach_node() time -- pseries: Get rid of open-coded tree modification from arch/powerpc/platforms/pseries/dlpar.c diff --git a/Documentation/devicetree/writing-schema.md b/Documentation/devicetree/writing-schema.md new file mode 100644 index 000000000000..a3652d33a48f --- /dev/null +++ b/Documentation/devicetree/writing-schema.md @@ -0,0 +1,130 @@ +# Writing DeviceTree Bindings in json-schema + +Devicetree bindings are written using json-schema vocabulary. Schema files are +written in a JSON compatible subset of YAML. YAML is used instead of JSON as it +considered more human readable and has some advantages such as allowing +comments (Prefixed with '#'). + +## Schema Contents + +Each schema doc is a structured json-schema which is defined by a set of +top-level properties. Generally, there is one binding defined per file. The +top-level json-schema properties used are: + +- __$id__ - A json-schema unique identifier string. The string must be a valid +URI typically containing the binding's filename and path. For DT schema, it must +begin with "http://devicetree.org/schemas/". The URL is used in constructing +references to other files specified in schema "$ref" properties. A $ref values +with a leading '/' will have the hostname prepended. A $ref value a relative +path or filename only will be prepended with the hostname and path components +of the current schema file's '$id' value. A URL is used even for local files, +but there may not actually be files present at those locations. + +- __$schema__ - Indicates the meta-schema the schema file adheres to. + +- __title__ - A one line description on the contents of the binding schema. + +- __maintainers__ - A DT specific property. Contains a list of email address(es) +for maintainers of this binding. + +- __description__ - Optional. A multi-line text block containing any detailed +information about this binding. It should contain things such as what the block +or device does, standards the device conforms to, and links to datasheets for +more information. + +- __select__ - Optional. A json-schema used to match nodes for applying the +schema. By default without 'select', nodes are matched against their possible +compatible string values or node name. Most bindings should not need select. + +- __allOf__ - Optional. A list of other schemas to include. This is used to +include other schemas the binding conforms to. This may be schemas for a +particular class of devices such as I2C or SPI controllers. + +- __properties__ - A set of sub-schema defining all the DT properties for the +binding. The exact schema syntax depends on whether properties are known, +common properties (e.g. 'interrupts') or are binding/vendor specific properties. + + A property can also define a child DT node with child properties defined +under it. + + For more details on properties sections, see 'Property Schema' section. + +- __patternProperties__ - Optional. Similar to 'properties', but names are regex. + +- __required__ - A list of DT properties from the 'properties' section that +must always be present. + +- __examples__ - Optional. A list of one or more DTS hunks implementing the +binding. Note: YAML doesn't allow leading tabs, so spaces must be used instead. + +Unless noted otherwise, all properties are required. + +## Property Schema + +The 'properties' section of the schema contains all the DT properties for a +binding. Each property contains a set of constraints using json-schema +vocabulary for that property. The properties schemas are what is used for +validation of DT files. + +For common properties, only additional constraints not covered by the common +binding schema need to be defined such as how many values are valid or what +possible values are valid. + +Vendor specific properties will typically need more detailed schema. With the +exception of boolean properties, they should have a reference to a type in +schemas/types.yaml. A "description" property is always required. + +The Devicetree schemas don't exactly match the YAML encoded DT data produced by +dtc. They are simplified to make them more compact and avoid a bunch of +boilerplate. The tools process the schema files to produce the final schema for +validation. There are currently 2 transformations the tools perform. + +The default for arrays in json-schema is they are variable sized and allow more +entries than explicitly defined. This can be restricted by defining 'minItems', +'maxItems', and 'additionalItems'. However, for DeviceTree Schemas, a fixed +size is desired in most cases, so these properties are added based on the +number of entries in an 'items' list. + +The YAML Devicetree format also makes all string values an array and scalar +values a matrix (in order to define groupings) even when only a single value +is present. Single entries in schemas are fixed up to match this encoding. + +## Testing + +### Dependencies + +The DT schema project must be installed in order to validate the DT schema +binding documents and validate DTS files using the DT schema. The DT schema +project can be installed with pip: + +`pip3 install git+https://github.com/robherring/yaml-bindings.git@master` + +dtc must also be built with YAML output support enabled. This requires that +libyaml and its headers be installed on the host system. + +### Running checks + +The DT schema binding documents must be validated using the meta-schema (the +schema for the schema) to ensure they are both valid json-schema and valid +binding schema. All of the DT binding documents can be validated using the +`dt_binding_check` target: + +`make dt_binding_check` + +In order to perform validation of DT source files, use the `dtbs_check` target: + +`make dtbs_check` + +This will first run the `dt_binding_check` which generates the processed schema. + +It is also possible to run checks with a single schema file by setting the +'DT_SCHEMA_FILES' variable to a specific schema file. + +`make dtbs_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/trivial-devices.yaml` + + +## json-schema Resources + +[JSON-Schema Specifications](http://json-schema.org/) + +[Using JSON Schema Book](http://usingjsonschema.com/) diff --git a/Documentation/doc-guide/kernel-doc.rst b/Documentation/doc-guide/kernel-doc.rst index 8db53cdc225f..51be62aa4385 100644 --- a/Documentation/doc-guide/kernel-doc.rst +++ b/Documentation/doc-guide/kernel-doc.rst @@ -77,7 +77,7 @@ The general format of a function and function-like macro kernel-doc comment is:: * Context: Describes whether the function can sleep, what locks it takes, * releases, or expects to be held. It can extend over multiple * lines. - * Return: Describe the return value of foobar. + * Return: Describe the return value of function_name. * * The return value description can also have multiple paragraphs, and should * be placed at the end of the comment block. diff --git a/Documentation/doc-guide/sphinx.rst b/Documentation/doc-guide/sphinx.rst index f0796daa95b4..02605ee1d876 100644 --- a/Documentation/doc-guide/sphinx.rst +++ b/Documentation/doc-guide/sphinx.rst @@ -1,3 +1,5 @@ +.. _sphinxdoc: + Introduction ============ diff --git a/Documentation/driver-api/dmaengine/dmatest.rst b/Documentation/driver-api/dmaengine/dmatest.rst index 7ce5e71c353e..8d81f1a7169b 100644 --- a/Documentation/driver-api/dmaengine/dmatest.rst +++ b/Documentation/driver-api/dmaengine/dmatest.rst @@ -11,6 +11,10 @@ This small document introduces how to test DMA drivers using dmatest module. capability of the following: DMA_MEMCPY (memory-to-memory), DMA_MEMSET (const-to-memory or memory-to-memory, when emulated), DMA_XOR, DMA_PQ. +.. note:: + In case of any related questions use the official mailing list + dmaengine@vger.kernel.org. + Part 1 - How to build the test module ===================================== @@ -26,28 +30,43 @@ Part 2 - When dmatest is built as a module Example of usage:: - % modprobe dmatest channel=dma0chan0 timeout=2000 iterations=1 run=1 + % modprobe dmatest timeout=2000 iterations=1 channel=dma0chan0 run=1 ...or:: % modprobe dmatest - % echo dma0chan0 > /sys/module/dmatest/parameters/channel % echo 2000 > /sys/module/dmatest/parameters/timeout % echo 1 > /sys/module/dmatest/parameters/iterations + % echo dma0chan0 > /sys/module/dmatest/parameters/channel % echo 1 > /sys/module/dmatest/parameters/run ...or on the kernel command line:: - dmatest.channel=dma0chan0 dmatest.timeout=2000 dmatest.iterations=1 dmatest.run=1 + dmatest.timeout=2000 dmatest.iterations=1 dmatest.channel=dma0chan0 dmatest.run=1 + +Example of multi-channel test usage: + % modprobe dmatest + % echo 2000 > /sys/module/dmatest/parameters/timeout + % echo 1 > /sys/module/dmatest/parameters/iterations + % echo dma0chan0 > /sys/module/dmatest/parameters/channel + % echo dma0chan1 > /sys/module/dmatest/parameters/channel + % echo dma0chan2 > /sys/module/dmatest/parameters/channel + % echo 1 > /sys/module/dmatest/parameters/run +Note: the channel parameter should always be the last parameter set prior to +running the test (setting run=1), this is because upon setting the channel +parameter, that specific channel is requested using the dmaengine and a thread +is created with the existing parameters. This thread is set as pending +and will be executed once run is set to 1. Any parameters set after the thread +is created are not applied. .. hint:: available channel list could be extracted by running the following command:: % ls -1 /sys/class/dma/ -Once started a message like "dmatest: Started 1 threads using dma0chan0" is -emitted. After that only test failure messages are reported until the test -stops. +Once started a message like " dmatest: Added 1 threads using dma0chan0" is +emitted. A thread for that specific channel is created and is now pending, the +pending thread is started once run is to 1. Note that running a new test will not stop any in progress test. @@ -112,3 +131,85 @@ Example:: The details of a data miscompare error are also emitted, but do not follow the above format. + +Part 5 - Handling channel allocation +==================================== + +Allocating Channels +------------------- + +Channels are required to be configured prior to starting the test run. +Attempting to run the test without configuring the channels will fail. + +Example:: + + % echo 1 > /sys/module/dmatest/parameters/run + dmatest: Could not start test, no channels configured + +Channels are registered using the "channel" parameter. Channels can be requested by their +name, once requested, the channel is registered and a pending thread is added to the test list. + +Example:: + + % echo dma0chan2 > /sys/module/dmatest/parameters/channel + dmatest: Added 1 threads using dma0chan2 + +More channels can be added by repeating the example above. +Reading back the channel parameter will return the name of last channel that was added successfully. + +Example:: + + % echo dma0chan1 > /sys/module/dmatest/parameters/channel + dmatest: Added 1 threads using dma0chan1 + % echo dma0chan2 > /sys/module/dmatest/parameters/channel + dmatest: Added 1 threads using dma0chan2 + % cat /sys/module/dmatest/parameters/channel + dma0chan2 + +Another method of requesting channels is to request a channel with an empty string, Doing so +will request all channels available to be tested: + +Example:: + + % echo "" > /sys/module/dmatest/parameters/channel + dmatest: Added 1 threads using dma0chan0 + dmatest: Added 1 threads using dma0chan3 + dmatest: Added 1 threads using dma0chan4 + dmatest: Added 1 threads using dma0chan5 + dmatest: Added 1 threads using dma0chan6 + dmatest: Added 1 threads using dma0chan7 + dmatest: Added 1 threads using dma0chan8 + +At any point during the test configuration, reading the "test_list" parameter will +print the list of currently pending tests. + +Example:: + + % cat /sys/module/dmatest/parameters/test_list + dmatest: 1 threads using dma0chan0 + dmatest: 1 threads using dma0chan3 + dmatest: 1 threads using dma0chan4 + dmatest: 1 threads using dma0chan5 + dmatest: 1 threads using dma0chan6 + dmatest: 1 threads using dma0chan7 + dmatest: 1 threads using dma0chan8 + +Note: Channels will have to be configured for each test run as channel configurations do not +carry across to the next test run. + +Releasing Channels +------------------- + +Channels can be freed by setting run to 0. + +Example:: + % echo dma0chan1 > /sys/module/dmatest/parameters/channel + dmatest: Added 1 threads using dma0chan1 + % cat /sys/class/dma/dma0chan1/in_use + 1 + % echo 0 > /sys/module/dmatest/parameters/run + % cat /sys/class/dma/dma0chan1/in_use + 0 + +Channels allocated by previous test runs are automatically freed when a new +channel is requested after completing a successful test run. diff --git a/Documentation/driver-api/firmware/other_interfaces.rst b/Documentation/driver-api/firmware/other_interfaces.rst index 36c47b1e9824..a4ac54b5fd79 100644 --- a/Documentation/driver-api/firmware/other_interfaces.rst +++ b/Documentation/driver-api/firmware/other_interfaces.rst @@ -13,3 +13,33 @@ EDD Interfaces .. kernel-doc:: drivers/firmware/edd.c :internal: +Intel Stratix10 SoC Service Layer +--------------------------------- +Some features of the Intel Stratix10 SoC require a level of privilege +higher than the kernel is granted. Such secure features include +FPGA programming. In terms of the ARMv8 architecture, the kernel runs +at Exception Level 1 (EL1), access to the features requires +Exception Level 3 (EL3). + +The Intel Stratix10 SoC service layer provides an in kernel API for +drivers to request access to the secure features. The requests are queued +and processed one by one. ARM’s SMCCC is used to pass the execution +of the requests on to a secure monitor (EL3). + +.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h + :functions: stratix10_svc_command_code + +.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h + :functions: stratix10_svc_client_msg + +.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h + :functions: stratix10_svc_command_reconfig_payload + +.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h + :functions: stratix10_svc_cb_data + +.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h + :functions: stratix10_svc_client + +.. kernel-doc:: drivers/firmware/stratix10-svc.c + :export: diff --git a/Documentation/driver-api/gpio/driver.rst b/Documentation/driver-api/gpio/driver.rst index a6c14ff0c54f..a92d8837b62b 100644 --- a/Documentation/driver-api/gpio/driver.rst +++ b/Documentation/driver-api/gpio/driver.rst @@ -434,7 +434,9 @@ try_module_get()). A GPIO driver can use the following functions instead to request and free descriptors without being pinned to the kernel forever:: struct gpio_desc *gpiochip_request_own_desc(struct gpio_desc *desc, - const char *label) + u16 hwnum, + const char *label, + enum gpiod_flags flags) void gpiochip_free_own_desc(struct gpio_desc *desc) diff --git a/Documentation/driver-api/pm/devices.rst b/Documentation/driver-api/pm/devices.rst index 1128705a5731..090c151aa86b 100644 --- a/Documentation/driver-api/pm/devices.rst +++ b/Documentation/driver-api/pm/devices.rst @@ -6,6 +6,8 @@ .. |struct wakeup_source| replace:: :c:type:`struct wakeup_source <wakeup_source>` .. |struct device| replace:: :c:type:`struct device <device>` +.. _driverapi_pm_devices: + ============================== Device Power Management Basics ============================== diff --git a/Documentation/driver-api/usb/index.rst b/Documentation/driver-api/usb/index.rst index 8fe995a1ec94..cfa8797ea614 100644 --- a/Documentation/driver-api/usb/index.rst +++ b/Documentation/driver-api/usb/index.rst @@ -19,6 +19,7 @@ Linux USB API dwc3 writing_musb_glue_layer typec + typec_bus usb3-debug-port .. only:: subproject and html diff --git a/Documentation/driver-api/usb/typec.rst b/Documentation/driver-api/usb/typec.rst index 48ff58095f11..201163d8c13e 100644 --- a/Documentation/driver-api/usb/typec.rst +++ b/Documentation/driver-api/usb/typec.rst @@ -1,3 +1,4 @@ +.. _typec: USB Type-C connector class ========================== diff --git a/Documentation/driver-api/usb/typec_bus.rst b/Documentation/driver-api/usb/typec_bus.rst index d5eec1715b5b..f47a69bff498 100644 --- a/Documentation/driver-api/usb/typec_bus.rst +++ b/Documentation/driver-api/usb/typec_bus.rst @@ -13,10 +13,10 @@ every alternate mode, so every alternate mode will need a custom driver. USB Type-C bus allows binding a driver to the discovered partner alternate modes by using the SVID and the mode number. -USB Type-C Connector Class provides a device for every alternate mode a port -supports, and separate device for every alternate mode the partner supports. -The drivers for the alternate modes are bound to the partner alternate mode -devices, and the port alternate mode devices must be handled by the port +:ref:`USB Type-C Connector Class <typec>` provides a device for every alternate +mode a port supports, and separate device for every alternate mode the partner +supports. The drivers for the alternate modes are bound to the partner alternate +mode devices, and the port alternate mode devices must be handled by the port drivers. When a new partner alternate mode device is registered, it is linked to the @@ -46,7 +46,7 @@ enter any modes on their own. ``->vdm`` is the most important callback in the operation callbacks vector. It will be used to deliver all the SVID specific commands from the partner to the alternate mode driver, and vice versa in case of port drivers. The drivers send -the SVID specific commands to each other using :c:func:`typec_altmode_vmd()`. +the SVID specific commands to each other using :c:func:`typec_altmode_vdm()`. If the communication with the partner using the SVID specific commands results in need to reconfigure the pins on the connector, the alternate mode driver @@ -67,15 +67,15 @@ Type-C Specification, and also put the connector back to ``TYPEC_STATE_USB`` after the mode has been exited. An example of working definitions for SVID specific pin configurations would -look like this: +look like this:: -enum { - ALTMODEX_CONF_A = TYPEC_STATE_MODAL, - ALTMODEX_CONF_B, - ... -}; + enum { + ALTMODEX_CONF_A = TYPEC_STATE_MODAL, + ALTMODEX_CONF_B, + ... + }; -Helper macro ``TYPEC_MODAL_STATE()`` can also be used: +Helper macro ``TYPEC_MODAL_STATE()`` can also be used:: #define ALTMODEX_CONF_A = TYPEC_MODAL_STATE(0); #define ALTMODEX_CONF_B = TYPEC_MODAL_STATE(1); diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt index fc4cc24dfb97..841c99529d27 100644 --- a/Documentation/driver-model/devres.txt +++ b/Documentation/driver-model/devres.txt @@ -132,6 +132,13 @@ devres. Complexity is shifted from less maintained low level drivers to better maintained higher layer. Also, as init failure path is shared with exit path, both can get more testing. +Note though that when converting current calls or assignments to +managed devm_* versions it is up to you to check if internal operations +like allocating memory, have failed. Managed resources pertains to the +freeing of these resources *only* - all other checks needed are still +on you. In some cases this may mean introducing checks that were not +necessary before moving to the managed devm_* calls. + 3. Devres group --------------- @@ -256,7 +263,6 @@ GPIO devm_gpiod_put() devm_gpiod_unhinge() devm_gpiochip_add_data() - devm_gpiochip_remove() devm_gpio_request() devm_gpio_request_one() devm_gpio_free() diff --git a/Documentation/early-userspace/README b/Documentation/early-userspace/README index 1e1057958dd3..955d667dc87e 100644 --- a/Documentation/early-userspace/README +++ b/Documentation/early-userspace/README @@ -52,7 +52,7 @@ user root (0). INITRAMFS_ROOT_GID can be set to a group ID that needs to be mapped to group root (0). A source file must be directives in the format required by the -usr/gen_init_cpio utility (run 'usr/gen_init_cpio --help' to get the +usr/gen_init_cpio utility (run 'usr/gen_init_cpio -h' to get the file format). The directives in the file will be passed directly to usr/gen_init_cpio. diff --git a/Documentation/features/core/jump-labels/arch-support.txt b/Documentation/features/core/jump-labels/arch-support.txt index 27cbd63abfd2..60111395f932 100644 --- a/Documentation/features/core/jump-labels/arch-support.txt +++ b/Documentation/features/core/jump-labels/arch-support.txt @@ -29,5 +29,5 @@ | um: | TODO | | unicore32: | TODO | | x86: | ok | - | xtensa: | TODO | + | xtensa: | ok | ----------------------- diff --git a/Documentation/features/io/sg-chain/arch-support.txt b/Documentation/features/io/sg-chain/arch-support.txt deleted file mode 100644 index 6554f0372c3f..000000000000 --- a/Documentation/features/io/sg-chain/arch-support.txt +++ /dev/null @@ -1,33 +0,0 @@ -# -# Feature name: sg-chain -# Kconfig: ARCH_HAS_SG_CHAIN -# description: arch supports chained scatter-gather lists -# - ----------------------- - | arch |status| - ----------------------- - | alpha: | TODO | - | arc: | ok | - | arm: | ok | - | arm64: | ok | - | c6x: | TODO | - | h8300: | TODO | - | hexagon: | TODO | - | ia64: | ok | - | m68k: | TODO | - | microblaze: | TODO | - | mips: | TODO | - | nds32: | TODO | - | nios2: | TODO | - | openrisc: | TODO | - | parisc: | TODO | - | powerpc: | ok | - | riscv: | TODO | - | s390: | ok | - | sh: | TODO | - | sparc: | ok | - | um: | TODO | - | unicore32: | TODO | - | x86: | ok | - | xtensa: | TODO | - ----------------------- diff --git a/Documentation/filesystems/caching/backend-api.txt b/Documentation/filesystems/caching/backend-api.txt index c0bd5677271b..c418280c915f 100644 --- a/Documentation/filesystems/caching/backend-api.txt +++ b/Documentation/filesystems/caching/backend-api.txt @@ -704,7 +704,7 @@ FS-Cache provides some utilities that a cache backend may make use of: void fscache_get_retrieval(struct fscache_retrieval *op); void fscache_put_retrieval(struct fscache_retrieval *op); - These two functions are used to retain a retrieval record whilst doing + These two functions are used to retain a retrieval record while doing asynchronous data retrieval and block allocation. diff --git a/Documentation/filesystems/caching/cachefiles.txt b/Documentation/filesystems/caching/cachefiles.txt index 748a1ae49e12..28aefcbb1442 100644 --- a/Documentation/filesystems/caching/cachefiles.txt +++ b/Documentation/filesystems/caching/cachefiles.txt @@ -45,7 +45,7 @@ filesystems are very specific in nature. CacheFiles creates a misc character device - "/dev/cachefiles" - that is used to communication with the daemon. Only one thing may have this open at once, -and whilst it is open, a cache is at least partially in existence. The daemon +and while it is open, a cache is at least partially in existence. The daemon opens this and sends commands down it to control the cache. CacheFiles is currently limited to a single cache. @@ -163,7 +163,7 @@ Do not mount other things within the cache as this will cause problems. The kernel module contains its own very cut-down path walking facility that ignores mountpoints, but the daemon can't avoid them. -Do not create, rename or unlink files and directories in the cache whilst the +Do not create, rename or unlink files and directories in the cache while the cache is active, as this may cause the state to become uncertain. Renaming files in the cache might make objects appear to be other objects (the diff --git a/Documentation/filesystems/caching/netfs-api.txt b/Documentation/filesystems/caching/netfs-api.txt index 2a6f7399c1f3..ba968e8f5704 100644 --- a/Documentation/filesystems/caching/netfs-api.txt +++ b/Documentation/filesystems/caching/netfs-api.txt @@ -382,7 +382,7 @@ MISCELLANEOUS OBJECT REGISTRATION An optional step is to request an object of miscellaneous type be created in the cache. This is almost identical to index cookie acquisition. The only difference is that the type in the object definition should be something other -than index type. Whilst the parent object could be an index, it's more likely +than index type. While the parent object could be an index, it's more likely it would be some other type of object such as a data file. xattr->cache = diff --git a/Documentation/filesystems/caching/operations.txt b/Documentation/filesystems/caching/operations.txt index a1c052cbba35..d8976c434718 100644 --- a/Documentation/filesystems/caching/operations.txt +++ b/Documentation/filesystems/caching/operations.txt @@ -171,7 +171,7 @@ Operations are used through the following procedure: (3) If the submitting thread wants to do the work itself, and has marked the operation with FSCACHE_OP_MYTHREAD, then it should monitor FSCACHE_OP_WAITING as described above and check the state of the object if - necessary (the object might have died whilst the thread was waiting). + necessary (the object might have died while the thread was waiting). When it has finished doing its processing, it should call fscache_op_complete() and fscache_put_operation() on it. diff --git a/Documentation/filesystems/cifs/TODO b/Documentation/filesystems/cifs/TODO index 852499aed64b..66b3f54aa6dc 100644 --- a/Documentation/filesystems/cifs/TODO +++ b/Documentation/filesystems/cifs/TODO @@ -1,4 +1,4 @@ -Version 2.11 September 13, 2017 +Version 2.14 December 21, 2018 A Partial List of Missing Features ================================== @@ -7,7 +7,7 @@ Contributions are welcome. There are plenty of opportunities for visible, important contributions to this module. Here is a partial list of the known problems and missing features: -a) SMB3 (and SMB3.02) missing optional features: +a) SMB3 (and SMB3.1.1) missing optional features: - multichannel (started), integration with RDMA - directory leases (improved metadata caching), started (root dir only) - T10 copy offload ie "ODX" (copy chunk, and "Duplicate Extents" ioctl @@ -21,8 +21,9 @@ using Directory Leases, currently only the root file handle is cached longer d) quota support (needs minor kernel change since quota calls to make it to network filesystems or deviceless filesystems) -e) Compounding (in progress) to reduce number of roundtrips, and also -better optimize open to reduce redundant opens (using reference counts more). +e) Additional use cases where we use "compoounding" (e.g. open/query/close +and open/setinfo/close) to reduce the number of roundtrips, and also +open to reduce redundant opens (using deferred close and reference counts more). f) Finish inotify support so kde and gnome file list windows will autorefresh (partially complete by Asser). Needs minor kernel @@ -43,11 +44,13 @@ exists. Also better integration with winbind for resolving SID owners k) Add tools to take advantage of more smb3 specific ioctls and features (passthrough ioctl/fsctl for sending various SMB3 fsctls to the server -is in progress) +is in progress, and a passthrough query_info call is already implemented +in cifs.ko to allow smb3 info levels queries to be sent from userspace) l) encrypted file support -m) improved stats gathering, tools (perhaps integration with nfsometer?) +m) improved stats gathering tools (perhaps integration with nfsometer?) +to extend and make easier to use what is currently in /proc/fs/cifs/Stats n) allow setting more NTFS/SMB3 file attributes remotely (currently limited to compressed file attribute via chflags) and improve user space tools for managing and @@ -76,6 +79,9 @@ and simplify the code. v) POSIX Extensions for SMB3.1.1 (started, create and mkdir support added so far). +w) Add support for additional strong encryption types, and additional spnego +authentication mechanisms (see MS-SMB2) + KNOWN BUGS ==================================== See http://bugzilla.samba.org - search on product "CifsVFS" for @@ -102,3 +108,11 @@ and when signing is disabled to request larger read sizes (larger than negotiated size) and send larger write sizes to modern servers. 4) More exhaustively test against less common servers + +5) Continue to extend the smb3 "buildbot" which does automated xfstesting +against Windows, Samba and Azure currently - to add additional tests and +to allow the buildbot to execute the tests faster. + +6) Address various coverity warnings (most are not bugs per-se, but +the more warnings are addressed, the easier it is to spot real +problems that static analyzers will point out in the future). diff --git a/Documentation/filesystems/configfs/configfs.txt b/Documentation/filesystems/configfs/configfs.txt index 3828e85345ae..16e606c11f40 100644 --- a/Documentation/filesystems/configfs/configfs.txt +++ b/Documentation/filesystems/configfs/configfs.txt @@ -216,7 +216,7 @@ be called whenever userspace asks for a write(2) on the attribute. [struct configfs_bin_attribute] - struct configfs_attribute { + struct configfs_bin_attribute { struct configfs_attribute cb_attr; void *cb_private; size_t cb_max_size; diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst index 46d1b1be3a51..605befab300b 100644 --- a/Documentation/filesystems/index.rst +++ b/Documentation/filesystems/index.rst @@ -359,3 +359,24 @@ encryption of files and directories. :maxdepth: 2 fscrypt + +Pathname lookup +=============== + + +This write-up is based on three articles published at lwn.net: + +- <https://lwn.net/Articles/649115/> Pathname lookup in Linux +- <https://lwn.net/Articles/649729/> RCU-walk: faster pathname lookup in Linux +- <https://lwn.net/Articles/650786/> A walk among the symlinks + +Written by Neil Brown with help from Al Viro and Jon Corbet. +It has subsequently been updated to reflect changes in the kernel +including: + +- per-directory parallel name lookup. + +.. toctree:: + :maxdepth: 2 + + path-lookup.rst diff --git a/Documentation/filesystems/path-lookup.md b/Documentation/filesystems/path-lookup.rst index e2edd45c4bc0..9d6b68853f5b 100644 --- a/Documentation/filesystems/path-lookup.md +++ b/Documentation/filesystems/path-lookup.rst @@ -1,20 +1,6 @@ -<head> -<style> p { max-width:50em} ol, ul {max-width: 40em}</style> -</head> -Pathname lookup in Linux. -========================= - -This write-up is based on three articles published at lwn.net: - -- <https://lwn.net/Articles/649115/> Pathname lookup in Linux -- <https://lwn.net/Articles/649729/> RCU-walk: faster pathname lookup in Linux -- <https://lwn.net/Articles/650786/> A walk among the symlinks - -Written by Neil Brown with help from Al Viro and Jon Corbet. - -Introduction ------------- +Introduction to pathname lookup +=============================== The most obvious aspect of pathname lookup, which very little exploration is needed to discover, is that it is complex. There are @@ -32,58 +18,58 @@ distinctions we need to clarify first. There are two sorts of ... -------------------------- -[`openat()`]: http://man7.org/linux/man-pages/man2/openat.2.html +.. _openat: http://man7.org/linux/man-pages/man2/openat.2.html Pathnames (sometimes "file names"), used to identify objects in the filesystem, will be familiar to most readers. They contain two sorts -of elements: "slashes" that are sequences of one or more "`/`" +of elements: "slashes" that are sequences of one or more "``/``" characters, and "components" that are sequences of one or more -non-"`/`" characters. These form two kinds of paths. Those that +non-"``/``" characters. These form two kinds of paths. Those that start with slashes are "absolute" and start from the filesystem root. The others are "relative" and start from the current directory, or from some other location specified by a file descriptor given to a -"xxx`at`" system call such as "[`openat()`]". +"``XXXat``" system call such as `openat() <openat_>`_. -[`execveat()`]: http://man7.org/linux/man-pages/man2/execveat.2.html +.. _execveat: http://man7.org/linux/man-pages/man2/execveat.2.html It is tempting to describe the second kind as starting with a component, but that isn't always accurate: a pathname can lack both slashes and components, it can be empty, in other words. This is -generally forbidden in POSIX, but some of those "xxx`at`" system calls -in Linux permit it when the `AT_EMPTY_PATH` flag is given. For +generally forbidden in POSIX, but some of those "xxx``at``" system calls +in Linux permit it when the ``AT_EMPTY_PATH`` flag is given. For example, if you have an open file descriptor on an executable file you -can execute it by calling [`execveat()`] passing the file descriptor, -an empty path, and the `AT_EMPTY_PATH` flag. +can execute it by calling `execveat() <execveat_>`_ passing +the file descriptor, an empty path, and the ``AT_EMPTY_PATH`` flag. These paths can be divided into two sections: the final component and everything else. The "everything else" is the easy bit. In all cases it must identify a directory that already exists, otherwise an error -such as `ENOENT` or `ENOTDIR` will be reported. +such as ``ENOENT`` or ``ENOTDIR`` will be reported. The final component is not so simple. Not only do different system calls interpret it quite differently (e.g. some create it, some do not), but it might not even exist: neither the empty pathname nor the pathname that is just slashes have a final component. If it does -exist, it could be "`.`" or "`..`" which are handled quite differently +exist, it could be "``.``" or "``..``" which are handled quite differently from other components. -[POSIX]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_12 +.. _POSIX: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_12 -If a pathname ends with a slash, such as "`/tmp/foo/`" it might be +If a pathname ends with a slash, such as "``/tmp/foo/``" it might be tempting to consider that to have an empty final component. In many ways that would lead to correct results, but not always. In -particular, `mkdir()` and `rmdir()` each create or remove a directory named +particular, ``mkdir()`` and ``rmdir()`` each create or remove a directory named by the final component, and they are required to work with pathnames -ending in "`/`". According to [POSIX] +ending in "``/``". According to POSIX_ -> A pathname that contains at least one non- <slash> character and -> that ends with one or more trailing <slash> characters shall not -> be resolved successfully unless the last pathname component before -> the trailing <slash> characters names an existing directory or a -> directory entry that is to be created for a directory immediately -> after the pathname is resolved. + A pathname that contains at least one non- <slash> character and + that ends with one or more trailing <slash> characters shall not + be resolved successfully unless the last pathname component before + the trailing <slash> characters names an existing directory or a + directory entry that is to be created for a directory immediately + after the pathname is resolved. -The Linux pathname walking code (mostly in `fs/namei.c`) deals with +The Linux pathname walking code (mostly in ``fs/namei.c``) deals with all of these issues: breaking the path into components, handling the "everything else" quite separately from the final component, and checking that the trailing slash is not used where it isn't @@ -100,15 +86,15 @@ of the possible races are seen most clearly in the context of the "dcache" and an understanding of that is central to understanding pathname lookup. -More than just a cache. ------------------------ +More than just a cache +---------------------- The "dcache" caches information about names in each filesystem to make them quickly available for lookup. Each entry (known as a "dentry") contains three significant fields: a component name, a pointer to a parent dentry, and a pointer to the "inode" which contains further information about the object in that parent with -the given name. The inode pointer can be `NULL` indicating that the +the given name. The inode pointer can be ``NULL`` indicating that the name doesn't exist in the parent. While there can be linkage in the dentry of a directory to the dentries of the children, that linkage is not used for pathname lookup, and so will not be considered here. @@ -135,7 +121,7 @@ whether remote filesystems like NFS and 9P, or cluster filesystems like ocfs2 or cephfs. These filesystems allow the VFS to revalidate cached information, and must provide their own protection against awkward races. The VFS can detect these filesystems by the -`DCACHE_OP_REVALIDATE` flag being set in the dentry. +``DCACHE_OP_REVALIDATE`` flag being set in the dentry. REF-walk: simple concurrency management with refcounts and spinlocks -------------------------------------------------------------------- @@ -144,22 +130,23 @@ With all of those divisions carefully classified, we can now start looking at the actual process of walking along a path. In particular we will start with the handling of the "everything else" part of a pathname, and focus on the "REF-walk" approach to concurrency -management. This code is found in the `link_path_walk()` function, if -you ignore all the places that only run when "`LOOKUP_RCU`" +management. This code is found in the ``link_path_walk()`` function, if +you ignore all the places that only run when "``LOOKUP_RCU``" (indicating the use of RCU-walk) is set. -[Meet the Lockers]: https://lwn.net/Articles/453685/ +.. _Meet the Lockers: https://lwn.net/Articles/453685/ REF-walk is fairly heavy-handed with locks and reference counts. Not as heavy-handed as in the old "big kernel lock" days, but certainly not afraid of taking a lock when one is needed. It uses a variety of different concurrency controls. A background understanding of the various primitives is assumed, or can be gleaned from elsewhere such -as in [Meet the Lockers]. +as in `Meet the Lockers`_. The locking mechanisms used by REF-walk include: -### dentry->d_lockref ### +dentry->d_lockref +~~~~~~~~~~~~~~~~~ This uses the lockref primitive to provide both a spinlock and a reference count. The special-sauce of this primitive is that the @@ -168,49 +155,51 @@ with a single atomic memory operation. Holding a reference on a dentry ensures that the dentry won't suddenly be freed and used for something else, so the values in various fields -will behave as expected. It also protects the `->d_inode` reference +will behave as expected. It also protects the ``->d_inode`` reference to the inode to some extent. The association between a dentry and its inode is fairly permanent. For example, when a file is renamed, the dentry and inode move together to the new location. When a file is created the dentry will -initially be negative (i.e. `d_inode` is `NULL`), and will be assigned +initially be negative (i.e. ``d_inode`` is ``NULL``), and will be assigned to the new inode as part of the act of creation. When a file is deleted, this can be reflected in the cache either by -setting `d_inode` to `NULL`, or by removing it from the hash table +setting ``d_inode`` to ``NULL``, or by removing it from the hash table (described shortly) used to look up the name in the parent directory. If the dentry is still in use the second option is used as it is perfectly legal to keep using an open file after it has been deleted and having the dentry around helps. If the dentry is not otherwise in -use (i.e. if the refcount in `d_lockref` is one), only then will -`d_inode` be set to `NULL`. Doing it this way is more efficient for a +use (i.e. if the refcount in ``d_lockref`` is one), only then will +``d_inode`` be set to ``NULL``. Doing it this way is more efficient for a very common case. -So as long as a counted reference is held to a dentry, a non-`NULL` `->d_inode` +So as long as a counted reference is held to a dentry, a non-``NULL`` ``->d_inode`` value will never be changed. -### dentry->d_lock ### +dentry->d_lock +~~~~~~~~~~~~~~ -`d_lock` is a synonym for the spinlock that is part of `d_lockref` above. +``d_lock`` is a synonym for the spinlock that is part of ``d_lockref`` above. For our purposes, holding this lock protects against the dentry being -renamed or unlinked. In particular, its parent (`d_parent`), and its -name (`d_name`) cannot be changed, and it cannot be removed from the +renamed or unlinked. In particular, its parent (``d_parent``), and its +name (``d_name``) cannot be changed, and it cannot be removed from the dentry hash table. -When looking for a name in a directory, REF-walk takes `d_lock` on +When looking for a name in a directory, REF-walk takes ``d_lock`` on each candidate dentry that it finds in the hash table and then checks that the parent and name are correct. So it doesn't lock the parent while searching in the cache; it only locks children. -When looking for the parent for a given name (to handle "`..`"), -REF-walk can take `d_lock` to get a stable reference to `d_parent`, +When looking for the parent for a given name (to handle "``..``"), +REF-walk can take ``d_lock`` to get a stable reference to ``d_parent``, but it first tries a more lightweight approach. As seen in -`dget_parent()`, if a reference can be claimed on the parent, and if -subsequently `d_parent` can be seen to have not changed, then there is +``dget_parent()``, if a reference can be claimed on the parent, and if +subsequently ``d_parent`` can be seen to have not changed, then there is no need to actually take the lock on the child. -### rename_lock ### +rename_lock +~~~~~~~~~~~ Looking up a given name in a given directory involves computing a hash from the two values (the name and the dentry of the directory), @@ -224,71 +213,117 @@ happened to be looking at a dentry that was moved in this way, it might end up continuing the search down the wrong chain, and so miss out on part of the correct chain. -The name-lookup process (`d_lookup()`) does _not_ try to prevent this +The name-lookup process (``d_lookup()``) does _not_ try to prevent this from happening, but only to detect when it happens. -`rename_lock` is a seqlock that is updated whenever any dentry is -renamed. If `d_lookup` finds that a rename happened while it +``rename_lock`` is a seqlock that is updated whenever any dentry is +renamed. If ``d_lookup`` finds that a rename happened while it unsuccessfully scanned a chain in the hash table, it simply tries again. -### inode->i_mutex ### +inode->i_rwsem +~~~~~~~~~~~~~~ -`i_mutex` is a mutex that serializes all changes to a particular -directory. This ensures that, for example, an `unlink()` and a `rename()` +``i_rwsem`` is a read/write semaphore that serializes all changes to a particular +directory. This ensures that, for example, an ``unlink()`` and a ``rename()`` cannot both happen at the same time. It also keeps the directory stable while the filesystem is asked to look up a name that is not -currently in the dcache. +currently in the dcache or, optionally, when the list of entries in a +directory is being retrieved with ``readdir()``. -This has a complementary role to that of `d_lock`: `i_mutex` on a -directory protects all of the names in that directory, while `d_lock` +This has a complementary role to that of ``d_lock``: ``i_rwsem`` on a +directory protects all of the names in that directory, while ``d_lock`` on a name protects just one name in a directory. Most changes to the -dcache hold `i_mutex` on the relevant directory inode and briefly take -`d_lock` on one or more the dentries while the change happens. One +dcache hold ``i_rwsem`` on the relevant directory inode and briefly take +``d_lock`` on one or more the dentries while the change happens. One exception is when idle dentries are removed from the dcache due to -memory pressure. This uses `d_lock`, but `i_mutex` plays no role. +memory pressure. This uses ``d_lock``, but ``i_rwsem`` plays no role. -The mutex affects pathname lookup in two distinct ways. Firstly it -serializes lookup of a name in a directory. `walk_component()` uses -`lookup_fast()` first which, in turn, checks to see if the name is in the cache, -using only `d_lock` locking. If the name isn't found, then `walk_component()` -falls back to `lookup_slow()` which takes `i_mutex`, checks again that +The semaphore affects pathname lookup in two distinct ways. Firstly it +prevents changes during lookup of a name in a directory. ``walk_component()`` uses +``lookup_fast()`` first which, in turn, checks to see if the name is in the cache, +using only ``d_lock`` locking. If the name isn't found, then ``walk_component()`` +falls back to ``lookup_slow()`` which takes a shared lock on ``i_rwsem``, checks again that the name isn't in the cache, and then calls in to the filesystem to get a definitive answer. A new dentry will be added to the cache regardless of the result. Secondly, when pathname lookup reaches the final component, it will -sometimes need to take `i_mutex` before performing the last lookup so +sometimes need to take an exclusive lock on ``i_rwsem`` before performing the last lookup so that the required exclusion can be achieved. How path lookup chooses -to take, or not take, `i_mutex` is one of the +to take, or not take, ``i_rwsem`` is one of the issues addressed in a subsequent section. -### mnt->mnt_count ### - -`mnt_count` is a per-CPU reference counter on "`mount`" structures. +If two threads attempt to look up the same name at the same time - a +name that is not yet in the dcache - the shared lock on ``i_rwsem`` will +not prevent them both adding new dentries with the same name. As this +would result in confusion an extra level of interlocking is used, +based around a secondary hash table (``in_lookup_hashtable``) and a +per-dentry flag bit (``DCACHE_PAR_LOOKUP``). + +To add a new dentry to the cache while only holding a shared lock on +``i_rwsem``, a thread must call ``d_alloc_parallel()``. This allocates a +dentry, stores the required name and parent in it, checks if there +is already a matching dentry in the primary or secondary hash +tables, and if not, stores the newly allocated dentry in the secondary +hash table, with ``DCACHE_PAR_LOOKUP`` set. + +If a matching dentry was found in the primary hash table then that is +returned and the caller can know that it lost a race with some other +thread adding the entry. If no matching dentry is found in either +cache, the newly allocated dentry is returned and the caller can +detect this from the presence of ``DCACHE_PAR_LOOKUP``. In this case it +knows that it has won any race and now is responsible for asking the +filesystem to perform the lookup and find the matching inode. When +the lookup is complete, it must call ``d_lookup_done()`` which clears +the flag and does some other house keeping, including removing the +dentry from the secondary hash table - it will normally have been +added to the primary hash table already. Note that a ``struct +waitqueue_head`` is passed to ``d_alloc_parallel()``, and +``d_lookup_done()`` must be called while this ``waitqueue_head`` is still +in scope. + +If a matching dentry is found in the secondary hash table, +``d_alloc_parallel()`` has a little more work to do. It first waits for +``DCACHE_PAR_LOOKUP`` to be cleared, using a wait_queue that was passed +to the instance of ``d_alloc_parallel()`` that won the race and that +will be woken by the call to ``d_lookup_done()``. It then checks to see +if the dentry has now been added to the primary hash table. If it +has, the dentry is returned and the caller just sees that it lost any +race. If it hasn't been added to the primary hash table, the most +likely explanation is that some other dentry was added instead using +``d_splice_alias()``. In any case, ``d_alloc_parallel()`` repeats all the +look ups from the start and will normally return something from the +primary hash table. + +mnt->mnt_count +~~~~~~~~~~~~~~ + +``mnt_count`` is a per-CPU reference counter on "``mount``" structures. Per-CPU here means that incrementing the count is cheap as it only uses CPU-local memory, but checking if the count is zero is expensive as -it needs to check with every CPU. Taking a `mnt_count` reference +it needs to check with every CPU. Taking a ``mnt_count`` reference prevents the mount structure from disappearing as the result of regular unmount operations, but does not prevent a "lazy" unmount. So holding -`mnt_count` doesn't ensure that the mount remains in the namespace and, +``mnt_count`` doesn't ensure that the mount remains in the namespace and, in particular, doesn't stabilize the link to the mounted-on dentry. It -does, however, ensure that the `mount` data structure remains coherent, +does, however, ensure that the ``mount`` data structure remains coherent, and it provides a reference to the root dentry of the mounted -filesystem. So a reference through `->mnt_count` provides a stable +filesystem. So a reference through ``->mnt_count`` provides a stable reference to the mounted dentry, but not the mounted-on dentry. -### mount_lock ### +mount_lock +~~~~~~~~~~ -`mount_lock` is a global seqlock, a bit like `rename_lock`. It can be used to +``mount_lock`` is a global seqlock, a bit like ``rename_lock``. It can be used to check if any change has been made to any mount points. While walking down the tree (away from the root) this lock is used when crossing a mount point to check that the crossing was safe. That is, the value in the seqlock is read, then the code finds the mount that is mounted on the current directory, if there is one, and increments -the `mnt_count`. Finally the value in `mount_lock` is checked against +the ``mnt_count``. Finally the value in ``mount_lock`` is checked against the old value. If there is no change, then the crossing was safe. If there -was a change, the `mnt_count` is decremented and the whole process is +was a change, the ``mnt_count`` is decremented and the whole process is retried. When walking up the tree (towards the root) by following a ".." link, @@ -298,7 +333,8 @@ any changes to any mount points while stepping up. This locking is needed to stabilize the link to the mounted-on dentry, which the refcount on the mount itself doesn't ensure. -### RCU ### +RCU +~~~ Finally the global (but extremely lightweight) RCU read lock is held from time to time to ensure certain data structures don't get freed @@ -307,137 +343,141 @@ unexpectedly. In particular it is held while scanning chains in the dcache hash table, and the mount point hash table. -Bringing it together with `struct nameidata` +Bringing it together with ``struct nameidata`` -------------------------------------------- -[First edition Unix]: http://minnie.tuhs.org/cgi-bin/utree.pl?file=V1/u2.s +.. _First edition Unix: http://minnie.tuhs.org/cgi-bin/utree.pl?file=V1/u2.s Throughout the process of walking a path, the current status is stored -in a `struct nameidata`, "namei" being the traditional name - dating -all the way back to [First Edition Unix] - of the function that -converts a "name" to an "inode". `struct nameidata` contains (among +in a ``struct nameidata``, "namei" being the traditional name - dating +all the way back to `First Edition Unix`_ - of the function that +converts a "name" to an "inode". ``struct nameidata`` contains (among other fields): -### `struct path path` ### +``struct path path`` +~~~~~~~~~~~~~~~~~~ -A `path` contains a `struct vfsmount` (which is -embedded in a `struct mount`) and a `struct dentry`. Together these +A ``path`` contains a ``struct vfsmount`` (which is +embedded in a ``struct mount``) and a ``struct dentry``. Together these record the current status of the walk. They start out referring to the starting point (the current working directory, the root directory, or some other directory identified by a file descriptor), and are updated on each -step. A reference through `d_lockref` and `mnt_count` is always +step. A reference through ``d_lockref`` and ``mnt_count`` is always held. -### `struct qstr last` ### +``struct qstr last`` +~~~~~~~~~~~~~~~~~~ -This is a string together with a length (i.e. _not_ `nul` terminated) +This is a string together with a length (i.e. _not_ ``nul`` terminated) that is the "next" component in the pathname. -### `int last_type` ### +``int last_type`` +~~~~~~~~~~~~~~~ -This is one of `LAST_NORM`, `LAST_ROOT`, `LAST_DOT`, `LAST_DOTDOT`, or -`LAST_BIND`. The `last` field is only valid if the type is -`LAST_NORM`. `LAST_BIND` is used when following a symlink and no +This is one of ``LAST_NORM``, ``LAST_ROOT``, ``LAST_DOT``, ``LAST_DOTDOT``, or +``LAST_BIND``. The ``last`` field is only valid if the type is +``LAST_NORM``. ``LAST_BIND`` is used when following a symlink and no components of the symlink have been processed yet. Others should be fairly self-explanatory. -### `struct path root` ### +``struct path root`` +~~~~~~~~~~~~~~~~~~ This is used to hold a reference to the effective root of the filesystem. Often that reference won't be needed, so this field is only assigned the first time it is used, or when a non-standard root -is requested. Keeping a reference in the `nameidata` ensures that +is requested. Keeping a reference in the ``nameidata`` ensures that only one root is in effect for the entire path walk, even if it races -with a `chroot()` system call. +with a ``chroot()`` system call. The root is needed when either of two conditions holds: (1) either the -pathname or a symbolic link starts with a "'/'", or (2) a "`..`" -component is being handled, since "`..`" from the root must always stay +pathname or a symbolic link starts with a "'/'", or (2) a "``..``" +component is being handled, since "``..``" from the root must always stay at the root. The value used is usually the current root directory of the calling process. An alternate root can be provided as when -`sysctl()` calls `file_open_root()`, and when NFSv4 or Btrfs call -`mount_subtree()`. In each case a pathname is being looked up in a very +``sysctl()`` calls ``file_open_root()``, and when NFSv4 or Btrfs call +``mount_subtree()``. In each case a pathname is being looked up in a very specific part of the filesystem, and the lookup must not be allowed to -escape that subtree. It works a bit like a local `chroot()`. +escape that subtree. It works a bit like a local ``chroot()``. Ignoring the handling of symbolic links, we can now describe the -"`link_path_walk()`" function, which handles the lookup of everything +"``link_path_walk()``" function, which handles the lookup of everything except the final component as: -> Given a path (`name`) and a nameidata structure (`nd`), check that the -> current directory has execute permission and then advance `name` -> over one component while updating `last_type` and `last`. If that -> was the final component, then return, otherwise call -> `walk_component()` and repeat from the top. + Given a path (``name``) and a nameidata structure (``nd``), check that the + current directory has execute permission and then advance ``name`` + over one component while updating ``last_type`` and ``last``. If that + was the final component, then return, otherwise call + ``walk_component()`` and repeat from the top. -`walk_component()` is even easier. If the component is `LAST_DOTS`, -it calls `handle_dots()` which does the necessary locking as already -described. If it finds a `LAST_NORM` component it first calls -"`lookup_fast()`" which only looks in the dcache, but will ask the +``walk_component()`` is even easier. If the component is ``LAST_DOTS``, +it calls ``handle_dots()`` which does the necessary locking as already +described. If it finds a ``LAST_NORM`` component it first calls +"``lookup_fast()``" which only looks in the dcache, but will ask the filesystem to revalidate the result if it is that sort of filesystem. -If that doesn't get a good result, it calls "`lookup_slow()`" which -takes the `i_mutex`, rechecks the cache, and then asks the filesystem +If that doesn't get a good result, it calls "``lookup_slow()``" which +takes ``i_rwsem``, rechecks the cache, and then asks the filesystem to find a definitive answer. Each of these will call -`follow_managed()` (as described below) to handle any mount points. +``follow_managed()`` (as described below) to handle any mount points. -In the absence of symbolic links, `walk_component()` creates a new -`struct path` containing a counted reference to the new dentry and a -reference to the new `vfsmount` which is only counted if it is -different from the previous `vfsmount`. It then calls -`path_to_nameidata()` to install the new `struct path` in the -`struct nameidata` and drop the unneeded references. +In the absence of symbolic links, ``walk_component()`` creates a new +``struct path`` containing a counted reference to the new dentry and a +reference to the new ``vfsmount`` which is only counted if it is +different from the previous ``vfsmount``. It then calls +``path_to_nameidata()`` to install the new ``struct path`` in the +``struct nameidata`` and drop the unneeded references. This "hand-over-hand" sequencing of getting a reference to the new dentry before dropping the reference to the previous dentry may seem obvious, but is worth pointing out so that we will recognize its analogue in the "RCU-walk" version. -Handling the final component. ------------------------------ +Handling the final component +---------------------------- -`link_path_walk()` only walks as far as setting `nd->last` and -`nd->last_type` to refer to the final component of the path. It does -not call `walk_component()` that last time. Handling that final +``link_path_walk()`` only walks as far as setting ``nd->last`` and +``nd->last_type`` to refer to the final component of the path. It does +not call ``walk_component()`` that last time. Handling that final component remains for the caller to sort out. Those callers are -`path_lookupat()`, `path_parentat()`, `path_mountpoint()` and -`path_openat()` each of which handles the differing requirements of +``path_lookupat()``, ``path_parentat()``, ``path_mountpoint()`` and +``path_openat()`` each of which handles the differing requirements of different system calls. -`path_parentat()` is clearly the simplest - it just wraps a little bit -of housekeeping around `link_path_walk()` and returns the parent +``path_parentat()`` is clearly the simplest - it just wraps a little bit +of housekeeping around ``link_path_walk()`` and returns the parent directory and final component to the caller. The caller will be either -aiming to create a name (via `filename_create()`) or remove or rename -a name (in which case `user_path_parent()` is used). They will use -`i_mutex` to exclude other changes while they validate and then +aiming to create a name (via ``filename_create()``) or remove or rename +a name (in which case ``user_path_parent()`` is used). They will use +``i_rwsem`` to exclude other changes while they validate and then perform their operation. -`path_lookupat()` is nearly as simple - it is used when an existing -object is wanted such as by `stat()` or `chmod()`. It essentially just -calls `walk_component()` on the final component through a call to -`lookup_last()`. `path_lookupat()` returns just the final dentry. +``path_lookupat()`` is nearly as simple - it is used when an existing +object is wanted such as by ``stat()`` or ``chmod()``. It essentially just +calls ``walk_component()`` on the final component through a call to +``lookup_last()``. ``path_lookupat()`` returns just the final dentry. -`path_mountpoint()` handles the special case of unmounting which must +``path_mountpoint()`` handles the special case of unmounting which must not try to revalidate the mounted filesystem. It effectively -contains, through a call to `mountpoint_last()`, an alternate -implementation of `lookup_slow()` which skips that step. This is +contains, through a call to ``mountpoint_last()``, an alternate +implementation of ``lookup_slow()`` which skips that step. This is important when unmounting a filesystem that is inaccessible, such as one provided by a dead NFS server. -Finally `path_openat()` is used for the `open()` system call; it -contains, in support functions starting with "`do_last()`", all the +Finally ``path_openat()`` is used for the ``open()`` system call; it +contains, in support functions starting with "``do_last()``", all the complexity needed to handle the different subtleties of O_CREAT (with -or without O_EXCL), final "`/`" characters, and trailing symbolic +or without O_EXCL), final "``/``" characters, and trailing symbolic links. We will revisit this in the final part of this series, which -focuses on those symbolic links. "`do_last()`" will sometimes, but -not always, take `i_mutex`, depending on what it finds. +focuses on those symbolic links. "``do_last()``" will sometimes, but +not always, take ``i_rwsem``, depending on what it finds. Each of these, or the functions which call them, need to be alert to -the possibility that the final component is not `LAST_NORM`. If the +the possibility that the final component is not ``LAST_NORM``. If the goal of the lookup is to create something, then any value for -`last_type` other than `LAST_NORM` will result in an error. For -example if `path_parentat()` reports `LAST_DOTDOT`, then the caller +``last_type`` other than ``LAST_NORM`` will result in an error. For +example if ``path_parentat()`` reports ``LAST_DOTDOT``, then the caller won't try to create that name. They also check for trailing slashes -by testing `last.name[last.len]`. If there is any character beyond +by testing ``last.name[last.len]``. If there is any character beyond the final component, it must be a trailing slash. Revalidation and automounts @@ -448,12 +488,12 @@ process not yet covered. One is the handling of stale cache entries and the other is automounts. On filesystems that require it, the lookup routines will call the -`->d_revalidate()` dentry method to ensure that the cached information +``->d_revalidate()`` dentry method to ensure that the cached information is current. This will often confirm validity or update a few details from a server. In some cases it may find that there has been change further up the path and that something that was thought to be valid previously isn't really. When this happens the lookup of the whole -path is aborted and retried with the "`LOOKUP_REVAL`" flag set. This +path is aborted and retried with the "``LOOKUP_REVAL``" flag set. This forces revalidation to be more thorough. We will see more details of this retry process in the next article. @@ -465,52 +505,55 @@ tree, but a few notes specifically related to path lookup are in order here. The Linux VFS has a concept of "managed" dentries which is reflected -in function names such as "`follow_managed()`". There are three +in function names such as "``follow_managed()``". There are three potentially interesting things about these dentries corresponding -to three different flags that might be set in `dentry->d_flags`: +to three different flags that might be set in ``dentry->d_flags``: -### `DCACHE_MANAGE_TRANSIT` ### +``DCACHE_MANAGE_TRANSIT`` +~~~~~~~~~~~~~~~~~~~~~~~ If this flag has been set, then the filesystem has requested that the -`d_manage()` dentry operation be called before handling any possible +``d_manage()`` dentry operation be called before handling any possible mount point. This can perform two particular services: It can block to avoid races. If an automount point is being -unmounted, the `d_manage()` function will usually wait for that +unmounted, the ``d_manage()`` function will usually wait for that process to complete before letting the new lookup proceed and possibly trigger a new automount. It can selectively allow only some processes to transit through a mount point. When a server process is managing automounts, it may need to access a directory without triggering normal automount -processing. That server process can identify itself to the `autofs` +processing. That server process can identify itself to the ``autofs`` filesystem, which will then give it a special pass through -`d_manage()` by returning `-EISDIR`. +``d_manage()`` by returning ``-EISDIR``. -### `DCACHE_MOUNTED` ### +``DCACHE_MOUNTED`` +~~~~~~~~~~~~~~~~ This flag is set on every dentry that is mounted on. As Linux supports multiple filesystem namespaces, it is possible that the dentry may not be mounted on in *this* namespace, just in some other. So this flag is seen as a hint, not a promise. -If this flag is set, and `d_manage()` didn't return `-EISDIR`, -`lookup_mnt()` is called to examine the mount hash table (honoring the -`mount_lock` described earlier) and possibly return a new `vfsmount` -and a new `dentry` (both with counted references). +If this flag is set, and ``d_manage()`` didn't return ``-EISDIR``, +``lookup_mnt()`` is called to examine the mount hash table (honoring the +``mount_lock`` described earlier) and possibly return a new ``vfsmount`` +and a new ``dentry`` (both with counted references). -### `DCACHE_NEED_AUTOMOUNT` ### +``DCACHE_NEED_AUTOMOUNT`` +~~~~~~~~~~~~~~~~~~~~~~~ -If `d_manage()` allowed us to get this far, and `lookup_mnt()` didn't -find a mount point, then this flag causes the `d_automount()` dentry +If ``d_manage()`` allowed us to get this far, and ``lookup_mnt()`` didn't +find a mount point, then this flag causes the ``d_automount()`` dentry operation to be called. -The `d_automount()` operation can be arbitrarily complex and may +The ``d_automount()`` operation can be arbitrarily complex and may communicate with server processes etc. but it should ultimately either report that there was an error, that there was nothing to mount, or -should provide an updated `struct path` with new `dentry` and `vfsmount`. +should provide an updated ``struct path`` with new ``dentry`` and ``vfsmount``. -In the latter case, `finish_automount()` will be called to safely +In the latter case, ``finish_automount()`` will be called to safely install the new mount point into the mount table. There is no new locking of import here and it is important that no @@ -567,7 +610,7 @@ isn't in the cache, then it tries to stop gracefully and switch to REF-walk. This stopping requires getting a counted reference on the current -`vfsmount` and `dentry`, and ensuring that these are still valid - +``vfsmount`` and ``dentry``, and ensuring that these are still valid - that a path walk with REF-walk would have found the same entries. This is an invariant that RCU-walk must guarantee. It can only make decisions, such as selecting the next step, that are decisions which @@ -578,21 +621,21 @@ RCU-walk finds it cannot stop gracefully, it simply gives up and restarts from the top with REF-walk. This pattern of "try RCU-walk, if that fails try REF-walk" can be -clearly seen in functions like `filename_lookup()`, -`filename_parentat()`, `filename_mountpoint()`, -`do_filp_open()`, and `do_file_open_root()`. These five -correspond roughly to the four `path_`* functions we met earlier, -each of which calls `link_path_walk()`. The `path_*` functions are +clearly seen in functions like ``filename_lookup()``, +``filename_parentat()``, ``filename_mountpoint()``, +``do_filp_open()``, and ``do_file_open_root()``. These five +correspond roughly to the four ``path_``* functions we met earlier, +each of which calls ``link_path_walk()``. The ``path_*`` functions are called using different mode flags until a mode is found which works. -They are first called with `LOOKUP_RCU` set to request "RCU-walk". If -that fails with the error `ECHILD` they are called again with no +They are first called with ``LOOKUP_RCU`` set to request "RCU-walk". If +that fails with the error ``ECHILD`` they are called again with no special flag to request "REF-walk". If either of those report the -error `ESTALE` a final attempt is made with `LOOKUP_REVAL` set (and no -`LOOKUP_RCU`) to ensure that entries found in the cache are forcibly +error ``ESTALE`` a final attempt is made with ``LOOKUP_REVAL`` set (and no +``LOOKUP_RCU``) to ensure that entries found in the cache are forcibly revalidated - normally entries are only revalidated if the filesystem determines that they are too old to trust. -The `LOOKUP_RCU` attempt may drop that flag internally and switch to +The ``LOOKUP_RCU`` attempt may drop that flag internally and switch to REF-walk, but will never then try to switch back to RCU-walk. Places that trip up RCU-walk are much more likely to be near the leaves and so it is very unlikely that there will be much, if any, benefit from @@ -602,7 +645,7 @@ RCU and seqlocks: fast and light -------------------------------- RCU is, unsurprisingly, critical to RCU-walk mode. The -`rcu_read_lock()` is held for the entire time that RCU-walk is walking +``rcu_read_lock()`` is held for the entire time that RCU-walk is walking down a path. The particular guarantee it provides is that the key data structures - dentries, inodes, super_blocks, and mounts - will not be freed while the lock is held. They might be unlinked or @@ -614,7 +657,7 @@ seqlocks. As we saw above, REF-walk holds a counted reference to the current dentry and the current vfsmount, and does not release those references before taking references to the "next" dentry or vfsmount. It also -sometimes takes the `d_lock` spinlock. These references and locks are +sometimes takes the ``d_lock`` spinlock. These references and locks are taken to prevent certain changes from happening. RCU-walk must not take those references or locks and so cannot prevent such changes. Instead, it checks to see if a change has been made, and aborts or @@ -624,123 +667,126 @@ To preserve the invariant mentioned above (that RCU-walk may only make decisions that REF-walk could have made), it must make the checks at or near the same places that REF-walk holds the references. So, when REF-walk increments a reference count or takes a spinlock, RCU-walk -samples the status of a seqlock using `read_seqcount_begin()` or a +samples the status of a seqlock using ``read_seqcount_begin()`` or a similar function. When REF-walk decrements the count or drops the lock, RCU-walk checks if the sampled status is still valid using -`read_seqcount_retry()` or similar. +``read_seqcount_retry()`` or similar. However, there is a little bit more to seqlocks than that. If RCU-walk accesses two different fields in a seqlock-protected structure, or accesses the same field twice, there is no a priori guarantee of any consistency between those accesses. When consistency is needed - which it usually is - RCU-walk must take a copy and then -use `read_seqcount_retry()` to validate that copy. +use ``read_seqcount_retry()`` to validate that copy. -`read_seqcount_retry()` not only checks the sequence number, but also +``read_seqcount_retry()`` not only checks the sequence number, but also imposes a memory barrier so that no memory-read instruction from *before* the call can be delayed until *after* the call, either by the CPU or by the compiler. A simple example of this can be seen in -`slow_dentry_cmp()` which, for filesystems which do not use simple +``slow_dentry_cmp()`` which, for filesystems which do not use simple byte-wise name equality, calls into the filesystem to compare a name against a dentry. The length and name pointer are copied into local -variables, then `read_seqcount_retry()` is called to confirm the two -are consistent, and only then is `->d_compare()` called. When -standard filename comparison is used, `dentry_cmp()` is called -instead. Notably it does _not_ use `read_seqcount_retry()`, but +variables, then ``read_seqcount_retry()`` is called to confirm the two +are consistent, and only then is ``->d_compare()`` called. When +standard filename comparison is used, ``dentry_cmp()`` is called +instead. Notably it does _not_ use ``read_seqcount_retry()``, but instead has a large comment explaining why the consistency guarantee -isn't necessary. A subsequent `read_seqcount_retry()` will be +isn't necessary. A subsequent ``read_seqcount_retry()`` will be sufficient to catch any problem that could occur at this point. With that little refresher on seqlocks out of the way we can look at the bigger picture of how RCU-walk uses seqlocks. -### `mount_lock` and `nd->m_seq` ### +``mount_lock`` and ``nd->m_seq`` +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -We already met the `mount_lock` seqlock when REF-walk used it to +We already met the ``mount_lock`` seqlock when REF-walk used it to ensure that crossing a mount point is performed safely. RCU-walk uses it for that too, but for quite a bit more. -Instead of taking a counted reference to each `vfsmount` as it -descends the tree, RCU-walk samples the state of `mount_lock` at the +Instead of taking a counted reference to each ``vfsmount`` as it +descends the tree, RCU-walk samples the state of ``mount_lock`` at the start of the walk and stores this initial sequence number in the -`struct nameidata` in the `m_seq` field. This one lock and one -sequence number are used to validate all accesses to all `vfsmounts`, +``struct nameidata`` in the ``m_seq`` field. This one lock and one +sequence number are used to validate all accesses to all ``vfsmounts``, and all mount point crossings. As changes to the mount table are relatively rare, it is reasonable to fall back on REF-walk any time that any "mount" or "unmount" happens. -`m_seq` is checked (using `read_seqretry()`) at the end of an RCU-walk +``m_seq`` is checked (using ``read_seqretry()``) at the end of an RCU-walk sequence, whether switching to REF-walk for the rest of the path or when the end of the path is reached. It is also checked when stepping -down over a mount point (in `__follow_mount_rcu()`) or up (in -`follow_dotdot_rcu()`). If it is ever found to have changed, the +down over a mount point (in ``__follow_mount_rcu()``) or up (in +``follow_dotdot_rcu()``). If it is ever found to have changed, the whole RCU-walk sequence is aborted and the path is processed again by REF-walk. -If RCU-walk finds that `mount_lock` hasn't changed then it can be sure +If RCU-walk finds that ``mount_lock`` hasn't changed then it can be sure that, had REF-walk taken counted references on each vfsmount, the results would have been the same. This ensures the invariant holds, at least for vfsmount structures. -### `dentry->d_seq` and `nd->seq`. ### +``dentry->d_seq`` and ``nd->seq`` +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -In place of taking a count or lock on `d_reflock`, RCU-walk samples -the per-dentry `d_seq` seqlock, and stores the sequence number in the -`seq` field of the nameidata structure, so `nd->seq` should always be -the current sequence number of `nd->dentry`. This number needs to be +In place of taking a count or lock on ``d_reflock``, RCU-walk samples +the per-dentry ``d_seq`` seqlock, and stores the sequence number in the +``seq`` field of the nameidata structure, so ``nd->seq`` should always be +the current sequence number of ``nd->dentry``. This number needs to be revalidated after copying, and before using, the name, parent, or inode of the dentry. The handling of the name we have already looked at, and the parent is -only accessed in `follow_dotdot_rcu()` which fairly trivially follows +only accessed in ``follow_dotdot_rcu()`` which fairly trivially follows the required pattern, though it does so for three different cases. -When not at a mount point, `d_parent` is followed and its `d_seq` is +When not at a mount point, ``d_parent`` is followed and its ``d_seq`` is collected. When we are at a mount point, we instead follow the -`mnt->mnt_mountpoint` link to get a new dentry and collect its -`d_seq`. Then, after finally finding a `d_parent` to follow, we must +``mnt->mnt_mountpoint`` link to get a new dentry and collect its +``d_seq``. Then, after finally finding a ``d_parent`` to follow, we must check if we have landed on a mount point and, if so, must find that -mount point and follow the `mnt->mnt_root` link. This would imply a +mount point and follow the ``mnt->mnt_root`` link. This would imply a somewhat unusual, but certainly possible, circumstance where the starting point of the path lookup was in part of the filesystem that was mounted on, and so not visible from the root. -The inode pointer, stored in `->d_inode`, is a little more +The inode pointer, stored in ``->d_inode``, is a little more interesting. The inode will always need to be accessed at least twice, once to determine if it is NULL and once to verify access permissions. Symlink handling requires a validated inode pointer too. Rather than revalidating on each access, a copy is made on the first -access and it is stored in the `inode` field of `nameidata` from where +access and it is stored in the ``inode`` field of ``nameidata`` from where it can be safely accessed without further validation. -`lookup_fast()` is the only lookup routine that is used in RCU-mode, -`lookup_slow()` being too slow and requiring locks. It is in -`lookup_fast()` that we find the important "hand over hand" tracking +``lookup_fast()`` is the only lookup routine that is used in RCU-mode, +``lookup_slow()`` being too slow and requiring locks. It is in +``lookup_fast()`` that we find the important "hand over hand" tracking of the current dentry. -The current `dentry` and current `seq` number are passed to -`__d_lookup_rcu()` which, on success, returns a new `dentry` and a -new `seq` number. `lookup_fast()` then copies the inode pointer and -revalidates the new `seq` number. It then validates the old `dentry` -with the old `seq` number one last time and only then continues. This -process of getting the `seq` number of the new dentry and then -checking the `seq` number of the old exactly mirrors the process of +The current ``dentry`` and current ``seq`` number are passed to +``__d_lookup_rcu()`` which, on success, returns a new ``dentry`` and a +new ``seq`` number. ``lookup_fast()`` then copies the inode pointer and +revalidates the new ``seq`` number. It then validates the old ``dentry`` +with the old ``seq`` number one last time and only then continues. This +process of getting the ``seq`` number of the new dentry and then +checking the ``seq`` number of the old exactly mirrors the process of getting a counted reference to the new dentry before dropping that for the old dentry which we saw in REF-walk. -### No `inode->i_mutex` or even `rename_lock` ### +No ``inode->i_rwsem`` or even ``rename_lock`` +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -A mutex is a fairly heavyweight lock that can only be taken when it is -permissible to sleep. As `rcu_read_lock()` forbids sleeping, -`inode->i_mutex` plays no role in RCU-walk. If some other thread does -take `i_mutex` and modifies the directory in a way that RCU-walk needs +A semaphore is a fairly heavyweight lock that can only be taken when it is +permissible to sleep. As ``rcu_read_lock()`` forbids sleeping, +``inode->i_rwsem`` plays no role in RCU-walk. If some other thread does +take ``i_rwsem`` and modifies the directory in a way that RCU-walk needs to notice, the result will be either that RCU-walk fails to find the dentry that it is looking for, or it will find a dentry which -`read_seqretry()` won't validate. In either case it will drop down to +``read_seqretry()`` won't validate. In either case it will drop down to REF-walk mode which can take whatever locks are needed. -Though `rename_lock` could be used by RCU-walk as it doesn't require -any sleeping, RCU-walk doesn't bother. REF-walk uses `rename_lock` to +Though ``rename_lock`` could be used by RCU-walk as it doesn't require +any sleeping, RCU-walk doesn't bother. REF-walk uses ``rename_lock`` to protect against the possibility of hash chains in the dcache changing while they are being searched. This can result in failing to find something that actually is there. When RCU-walk fails to find @@ -749,57 +795,57 @@ already drops down to REF-walk and tries again with appropriate locking. This neatly handles all cases, so adding extra checks on rename_lock would bring no significant value. -`unlazy walk()` and `complete_walk()` +``unlazy walk()`` and ``complete_walk()`` ------------------------------------- That "dropping down to REF-walk" typically involves a call to -`unlazy_walk()`, so named because "RCU-walk" is also sometimes -referred to as "lazy walk". `unlazy_walk()` is called when +``unlazy_walk()``, so named because "RCU-walk" is also sometimes +referred to as "lazy walk". ``unlazy_walk()`` is called when following the path down to the current vfsmount/dentry pair seems to have proceeded successfully, but the next step is problematic. This can happen if the next name cannot be found in the dcache, if permission checking or name revalidation couldn't be achieved while -the `rcu_read_lock()` is held (which forbids sleeping), if an +the ``rcu_read_lock()`` is held (which forbids sleeping), if an automount point is found, or in a couple of cases involving symlinks. -It is also called from `complete_walk()` when the lookup has reached +It is also called from ``complete_walk()`` when the lookup has reached the final component, or the very end of the path, depending on which particular flavor of lookup is used. Other reasons for dropping out of RCU-walk that do not trigger a call -to `unlazy_walk()` are when some inconsistency is found that cannot be -handled immediately, such as `mount_lock` or one of the `d_seq` +to ``unlazy_walk()`` are when some inconsistency is found that cannot be +handled immediately, such as ``mount_lock`` or one of the ``d_seq`` seqlocks reporting a change. In these cases the relevant function -will return `-ECHILD` which will percolate up until it triggers a new +will return ``-ECHILD`` which will percolate up until it triggers a new attempt from the top using REF-walk. -For those cases where `unlazy_walk()` is an option, it essentially +For those cases where ``unlazy_walk()`` is an option, it essentially takes a reference on each of the pointers that it holds (vfsmount, dentry, and possibly some symbolic links) and then verifies that the relevant seqlocks have not been changed. If there have been changes, -it, too, aborts with `-ECHILD`, otherwise the transition to REF-walk +it, too, aborts with ``-ECHILD``, otherwise the transition to REF-walk has been a success and the lookup process continues. Taking a reference on those pointers is not quite as simple as just incrementing a counter. That works to take a second reference if you already have one (often indirectly through another object), but it isn't sufficient if you don't actually have a counted reference at -all. For `dentry->d_lockref`, it is safe to increment the reference +all. For ``dentry->d_lockref``, it is safe to increment the reference counter to get a reference unless it has been explicitly marked as -"dead" which involves setting the counter to `-128`. -`lockref_get_not_dead()` achieves this. +"dead" which involves setting the counter to ``-128``. +``lockref_get_not_dead()`` achieves this. -For `mnt->mnt_count` it is safe to take a reference as long as -`mount_lock` is then used to validate the reference. If that +For ``mnt->mnt_count`` it is safe to take a reference as long as +``mount_lock`` is then used to validate the reference. If that validation fails, it may *not* be safe to just drop that reference in -the standard way of calling `mnt_put()` - an unmount may have -progressed too far. So the code in `legitimize_mnt()`, when it +the standard way of calling ``mnt_put()`` - an unmount may have +progressed too far. So the code in ``legitimize_mnt()``, when it finds that the reference it got might not be safe, checks the -`MNT_SYNC_UMOUNT` flag to determine if a simple `mnt_put()` is +``MNT_SYNC_UMOUNT`` flag to determine if a simple ``mnt_put()`` is correct, or if it should just decrement the count and pretend none of this ever happened. Taking care in filesystems ---------------------------- +-------------------------- RCU-walk depends almost entirely on cached information and often will not call into the filesystem at all. However there are two places, @@ -809,26 +855,26 @@ careful. If the filesystem has non-standard permission-checking requirements - such as a networked filesystem which may need to check with the server -- the `i_op->permission` interface might be called during RCU-walk. -In this case an extra "`MAY_NOT_BLOCK`" flag is passed so that it -knows not to sleep, but to return `-ECHILD` if it cannot complete -promptly. `i_op->permission` is given the inode pointer, not the +- the ``i_op->permission`` interface might be called during RCU-walk. +In this case an extra "``MAY_NOT_BLOCK``" flag is passed so that it +knows not to sleep, but to return ``-ECHILD`` if it cannot complete +promptly. ``i_op->permission`` is given the inode pointer, not the dentry, so it doesn't need to worry about further consistency checks. However if it accesses any other filesystem data structures, it must -ensure they are safe to be accessed with only the `rcu_read_lock()` -held. This typically means they must be freed using `kfree_rcu()` or +ensure they are safe to be accessed with only the ``rcu_read_lock()`` +held. This typically means they must be freed using ``kfree_rcu()`` or similar. -[`READ_ONCE()`]: https://lwn.net/Articles/624126/ +.. _READ_ONCE: https://lwn.net/Articles/624126/ If the filesystem may need to revalidate dcache entries, then -`d_op->d_revalidate` may be called in RCU-walk too. This interface -*is* passed the dentry but does not have access to the `inode` or the -`seq` number from the `nameidata`, so it needs to be extra careful +``d_op->d_revalidate`` may be called in RCU-walk too. This interface +*is* passed the dentry but does not have access to the ``inode`` or the +``seq`` number from the ``nameidata``, so it needs to be extra careful when accessing fields in the dentry. This "extra care" typically -involves using [`READ_ONCE()`] to access fields, and verifying the +involves using `READ_ONCE() <READ_ONCE_>`_ to access fields, and verifying the result is not NULL before using it. This pattern can be seen in -`nfs_lookup_revalidate()`. +``nfs_lookup_revalidate()``. A pair of patterns ------------------ @@ -839,14 +885,14 @@ being aware of. The first is "try quickly and check, if that fails try slowly". We can see that in the high-level approach of first trying RCU-walk and -then trying REF-walk, and in places where `unlazy_walk()` is used to +then trying REF-walk, and in places where ``unlazy_walk()`` is used to switch to REF-walk for the rest of the path. We also saw it earlier -in `dget_parent()` when following a "`..`" link. It tries a quick way +in ``dget_parent()`` when following a "``..``" link. It tries a quick way to get a reference, then falls back to taking locks if needed. The second pattern is "try quickly and check, if that fails try -again - repeatedly". This is seen with the use of `rename_lock` and -`mount_lock` in REF-walk. RCU-walk doesn't make use of this pattern - +again - repeatedly". This is seen with the use of ``rename_lock`` and +``mount_lock`` in REF-walk. RCU-walk doesn't make use of this pattern - if anything goes wrong it is much safer to just abort and try a more sedate approach. @@ -882,8 +928,8 @@ Conceptually, symbolic links could be handled by editing the path. If a component name refers to a symbolic link, then that component is replaced by the body of the link and, if that body starts with a '/', then all preceding parts of the path are discarded. This is what the -"`readlink -f`" command does, though it also edits out "`.`" and -"`..`" components. +"``readlink -f``" command does, though it also edits out "``.``" and +"``..``" components. Directly editing the path string is not really necessary when looking up a path, and discarding early components is pointless as they aren't @@ -899,19 +945,19 @@ There are two reasons for placing limits on how many symlinks can occur in a single path lookup. The most obvious is to avoid loops. If a symlink referred to itself either directly or through intermediaries, then following the symlink can never complete -successfully - the error `ELOOP` must be returned. Loops can be +successfully - the error ``ELOOP`` must be returned. Loops can be detected without imposing limits, but limits are the simplest solution and, given the second reason for restriction, quite sufficient. -[outlined recently]: http://thread.gmane.org/gmane.linux.kernel/1934390/focus=1934550 +.. _outlined recently: http://thread.gmane.org/gmane.linux.kernel/1934390/focus=1934550 -The second reason was [outlined recently] by Linus: +The second reason was `outlined recently`_ by Linus: -> Because it's a latency and DoS issue too. We need to react well to -> true loops, but also to "very deep" non-loops. It's not about memory -> use, it's about users triggering unreasonable CPU resources. + Because it's a latency and DoS issue too. We need to react well to + true loops, but also to "very deep" non-loops. It's not about memory + use, it's about users triggering unreasonable CPU resources. -Linux imposes a limit on the length of any pathname: `PATH_MAX`, which +Linux imposes a limit on the length of any pathname: ``PATH_MAX``, which is 4096. There are a number of reasons for this limit; not letting the kernel spend too much time on just one path is one of them. With symbolic links you can effectively generate much longer paths so some @@ -921,7 +967,7 @@ further limit of eight on the maximum depth of recursion, but that was raised to 40 when a separate stack was implemented, so there is now just the one limit. -The `nameidata` structure that we met in an earlier article contains a +The ``nameidata`` structure that we met in an earlier article contains a small stack that can be used to store the remaining part of up to two symlinks. In many cases this will be sufficient. If it isn't, a separate stack is allocated with room for 40 symlinks. Pathname @@ -941,13 +987,13 @@ to external storage. It is particularly important for RCU-walk to be able to find and temporarily hold onto these cached entries, so that it doesn't need to drop down into REF-walk. -[object-oriented design pattern]: https://lwn.net/Articles/446317/ +.. _object-oriented design pattern: https://lwn.net/Articles/446317/ While each filesystem is free to make its own choice, symlinks are typically stored in one of two places. Short symlinks are often -stored directly in the inode. When a filesystem allocates a `struct -inode` it typically allocates extra space to store private data (a -common [object-oriented design pattern] in the kernel). This will +stored directly in the inode. When a filesystem allocates a ``struct +inode`` it typically allocates extra space to store private data (a +common `object-oriented design pattern`_ in the kernel). This will sometimes include space for a symlink. The other common location is in the page cache, which normally stores the content of files. The pathname in a symlink can be seen as the content of that symlink and @@ -962,13 +1008,13 @@ the inode which, itself, is protected by RCU or by a counted reference on the dentry. This means that the mechanisms that pathname lookup uses to access the dcache and icache (inode cache) safely are quite sufficient for accessing some cached symlinks safely. In these cases, -the `i_link` pointer in the inode is set to point to wherever the +the ``i_link`` pointer in the inode is set to point to wherever the symlink is stored and it can be accessed directly whenever needed. When the symlink is stored in the page cache or elsewhere, the situation is not so straightforward. A reference on a dentry or even on an inode does not imply any reference on cached pages of that -inode, and even an `rcu_read_lock()` is not sufficient to ensure that +inode, and even an ``rcu_read_lock()`` is not sufficient to ensure that a page will not disappear. So for these symlinks the pathname lookup code needs to ask the filesystem to provide a stable reference and, significantly, needs to release that reference when it is finished @@ -978,48 +1024,48 @@ Taking a reference to a cache page is often possible even in RCU-walk mode. It does require making changes to memory, which is best avoided, but that isn't necessarily a big cost and it is better than dropping out of RCU-walk mode completely. Even filesystems that allocate -space to copy the symlink into can use `GFP_ATOMIC` to often successfully +space to copy the symlink into can use ``GFP_ATOMIC`` to often successfully allocate memory without the need to drop out of RCU-walk. If a filesystem cannot successfully get a reference in RCU-walk mode, it -must return `-ECHILD` and `unlazy_walk()` will be called to return to +must return ``-ECHILD`` and ``unlazy_walk()`` will be called to return to REF-walk mode in which the filesystem is allowed to sleep. -The place for all this to happen is the `i_op->follow_link()` inode +The place for all this to happen is the ``i_op->follow_link()`` inode method. In the present mainline code this is never actually called in RCU-walk mode as the rewrite is not quite complete. It is likely that -in a future release this method will be passed an `inode` pointer when +in a future release this method will be passed an ``inode`` pointer when called in RCU-walk mode so it both (1) knows to be careful, and (2) has the -validated pointer. Much like the `i_op->permission()` method we -looked at previously, `->follow_link()` would need to be careful that +validated pointer. Much like the ``i_op->permission()`` method we +looked at previously, ``->follow_link()`` would need to be careful that all the data structures it references are safe to be accessed while holding no counted reference, only the RCU lock. Though getting a -reference with `->follow_link()` is not yet done in RCU-walk mode, the +reference with ``->follow_link()`` is not yet done in RCU-walk mode, the code is ready to release the reference when that does happen. This need to drop the reference to a symlink adds significant complexity. It requires a reference to the inode so that the -`i_op->put_link()` inode operation can be called. In REF-walk, that +``i_op->put_link()`` inode operation can be called. In REF-walk, that reference is kept implicitly through a reference to the dentry, so -keeping the `struct path` of the symlink is easiest. For RCU-walk, +keeping the ``struct path`` of the symlink is easiest. For RCU-walk, the pointer to the inode is kept separately. To allow switching from RCU-walk back to REF-walk in the middle of processing nested symlinks we also need the seq number for the dentry so we can confirm that switching back was safe. Finally, when providing a reference to a symlink, the filesystem also -provides an opaque "cookie" that must be passed to `->put_link()` so that it +provides an opaque "cookie" that must be passed to ``->put_link()`` so that it knows what to free. This might be the allocated memory area, or a -pointer to the `struct page` in the page cache, or something else +pointer to the ``struct page`` in the page cache, or something else completely. Only the filesystem knows what it is. In order for the reference to each symlink to be dropped when the walk completes, whether in RCU-walk or REF-walk, the symlink stack needs to contain, along with the path remnants: -- the `struct path` to provide a reference to the inode in REF-walk -- the `struct inode *` to provide a reference to the inode in RCU-walk -- the `seq` to allow the path to be safely switched from RCU-walk to REF-walk -- the `cookie` that tells `->put_path()` what to put. +- the ``struct path`` to provide a reference to the inode in REF-walk +- the ``struct inode *`` to provide a reference to the inode in RCU-walk +- the ``seq`` to allow the path to be safely switched from RCU-walk to REF-walk +- the ``cookie`` that tells ``->put_path()`` what to put. This means that each entry in the symlink stack needs to hold five pointers and an integer instead of just one pointer (the path @@ -1028,28 +1074,28 @@ with 40 entries it adds up to 1600 bytes total, which is less than half a page. So it might seem like a lot, but is by no means excessive. -Note that, in a given stack frame, the path remnant (`name`) is not +Note that, in a given stack frame, the path remnant (``name``) is not part of the symlink that the other fields refer to. It is the remnant to be followed once that symlink has been fully parsed. Following the symlink --------------------- -The main loop in `link_path_walk()` iterates seamlessly over all +The main loop in ``link_path_walk()`` iterates seamlessly over all components in the path and all of the non-final symlinks. As symlinks -are processed, the `name` pointer is adjusted to point to a new +are processed, the ``name`` pointer is adjusted to point to a new symlink, or is restored from the stack, so that much of the loop -doesn't need to notice. Getting this `name` variable on and off the +doesn't need to notice. Getting this ``name`` variable on and off the stack is very straightforward; pushing and popping the references is a little more complex. -When a symlink is found, `walk_component()` returns the value `1` -(`0` is returned for any other sort of success, and a negative number -is, as usual, an error indicator). This causes `get_link()` to be +When a symlink is found, ``walk_component()`` returns the value ``1`` +(``0`` is returned for any other sort of success, and a negative number +is, as usual, an error indicator). This causes ``get_link()`` to be called; it then gets the link from the filesystem. Providing that -operation is successful, the old path `name` is placed on the stack, -and the new value is used as the `name` for a while. When the end of -the path is found (i.e. `*name` is `'\0'`) the old `name` is restored +operation is successful, the old path ``name`` is placed on the stack, +and the new value is used as the ``name`` for a while. When the end of +the path is found (i.e. ``*name`` is ``'\0'``) the old ``name`` is restored off the stack and path walking continues. Pushing and popping the reference pointers (inode, cookie, etc.) is more @@ -1060,113 +1106,114 @@ the symlink-just-found to avoid leaving empty path remnants that would just get in the way. It is most convenient to push the new symlink references onto the -stack in `walk_component()` immediately when the symlink is found; -`walk_component()` is also the last piece of code that needs to look at the +stack in ``walk_component()`` immediately when the symlink is found; +``walk_component()`` is also the last piece of code that needs to look at the old symlink as it walks that last component. So it is quite -convenient for `walk_component()` to release the old symlink and pop +convenient for ``walk_component()`` to release the old symlink and pop the references just before pushing the reference information for the -new symlink. It is guided in this by two flags; `WALK_GET`, which +new symlink. It is guided in this by two flags; ``WALK_GET``, which gives it permission to follow a symlink if it finds one, and -`WALK_PUT`, which tells it to release the current symlink after it has been -followed. `WALK_PUT` is tested first, leading to a call to -`put_link()`. `WALK_GET` is tested subsequently (by -`should_follow_link()`) leading to a call to `pick_link()` which sets +``WALK_PUT``, which tells it to release the current symlink after it has been +followed. ``WALK_PUT`` is tested first, leading to a call to +``put_link()``. ``WALK_GET`` is tested subsequently (by +``should_follow_link()``) leading to a call to ``pick_link()`` which sets up the stack frame. -### Symlinks with no final component ### +Symlinks with no final component +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A pair of special-case symlinks deserve a little further explanation. -Both result in a new `struct path` (with mount and dentry) being set -up in the `nameidata`, and result in `get_link()` returning `NULL`. +Both result in a new ``struct path`` (with mount and dentry) being set +up in the ``nameidata``, and result in ``get_link()`` returning ``NULL``. -The more obvious case is a symlink to "`/`". All symlinks starting -with "`/`" are detected in `get_link()` which resets the `nameidata` +The more obvious case is a symlink to "``/``". All symlinks starting +with "``/``" are detected in ``get_link()`` which resets the ``nameidata`` to point to the effective filesystem root. If the symlink only -contains "`/`" then there is nothing more to do, no components at all, -so `NULL` is returned to indicate that the symlink can be released and +contains "``/``" then there is nothing more to do, no components at all, +so ``NULL`` is returned to indicate that the symlink can be released and the stack frame discarded. -The other case involves things in `/proc` that look like symlinks but -aren't really. +The other case involves things in ``/proc`` that look like symlinks but +aren't really:: -> $ ls -l /proc/self/fd/1 -> lrwx------ 1 neilb neilb 64 Jun 13 10:19 /proc/self/fd/1 -> /dev/pts/4 + $ ls -l /proc/self/fd/1 + lrwx------ 1 neilb neilb 64 Jun 13 10:19 /proc/self/fd/1 -> /dev/pts/4 -Every open file descriptor in any process is represented in `/proc` by +Every open file descriptor in any process is represented in ``/proc`` by something that looks like a symlink. It is really a reference to the -target file, not just the name of it. When you `readlink` these +target file, not just the name of it. When you ``readlink`` these objects you get a name that might refer to the same file - unless it -has been unlinked or mounted over. When `walk_component()` follows -one of these, the `->follow_link()` method in "procfs" doesn't return -a string name, but instead calls `nd_jump_link()` which updates the -`nameidata` in place to point to that target. `->follow_link()` then -returns `NULL`. Again there is no final component and `get_link()` -reports this by leaving the `last_type` field of `nameidata` as -`LAST_BIND`. +has been unlinked or mounted over. When ``walk_component()`` follows +one of these, the ``->follow_link()`` method in "procfs" doesn't return +a string name, but instead calls ``nd_jump_link()`` which updates the +``nameidata`` in place to point to that target. ``->follow_link()`` then +returns ``NULL``. Again there is no final component and ``get_link()`` +reports this by leaving the ``last_type`` field of ``nameidata`` as +``LAST_BIND``. Following the symlink in the final component -------------------------------------------- -All this leads to `link_path_walk()` walking down every component, and +All this leads to ``link_path_walk()`` walking down every component, and following all symbolic links it finds, until it reaches the final -component. This is just returned in the `last` field of `nameidata`. +component. This is just returned in the ``last`` field of ``nameidata``. For some callers, this is all they need; they want to create that -`last` name if it doesn't exist or give an error if it does. Other +``last`` name if it doesn't exist or give an error if it does. Other callers will want to follow a symlink if one is found, and possibly apply special handling to the last component of that symlink, rather than just the last component of the original file name. These callers -potentially need to call `link_path_walk()` again and again on +potentially need to call ``link_path_walk()`` again and again on successive symlinks until one is found that doesn't point to another symlink. -This case is handled by the relevant caller of `link_path_walk()`, such as -`path_lookupat()` using a loop that calls `link_path_walk()`, and then +This case is handled by the relevant caller of ``link_path_walk()``, such as +``path_lookupat()`` using a loop that calls ``link_path_walk()``, and then handles the final component. If the final component is a symlink -that needs to be followed, then `trailing_symlink()` is called to set -things up properly and the loop repeats, calling `link_path_walk()` +that needs to be followed, then ``trailing_symlink()`` is called to set +things up properly and the loop repeats, calling ``link_path_walk()`` again. This could loop as many as 40 times if the last component of each symlink is another symlink. The various functions that examine the final component and possibly -report that it is a symlink are `lookup_last()`, `mountpoint_last()` -and `do_last()`, each of which use the same convention as -`walk_component()` of returning `1` if a symlink was found that needs +report that it is a symlink are ``lookup_last()``, ``mountpoint_last()`` +and ``do_last()``, each of which use the same convention as +``walk_component()`` of returning ``1`` if a symlink was found that needs to be followed. -Of these, `do_last()` is the most interesting as it is used for -opening a file. Part of `do_last()` runs with `i_mutex` held and this -part is in a separate function: `lookup_open()`. +Of these, ``do_last()`` is the most interesting as it is used for +opening a file. Part of ``do_last()`` runs with ``i_rwsem`` held and this +part is in a separate function: ``lookup_open()``. -Explaining `do_last()` completely is beyond the scope of this article, +Explaining ``do_last()`` completely is beyond the scope of this article, but a few highlights should help those interested in exploring the code. -1. Rather than just finding the target file, `do_last()` needs to open - it. If the file was found in the dcache, then `vfs_open()` is used for - this. If not, then `lookup_open()` will either call `atomic_open()` (if - the filesystem provides it) to combine the final lookup with the open, or - will perform the separate `lookup_real()` and `vfs_create()` steps - directly. In the later case the actual "open" of this newly found or - created file will be performed by `vfs_open()`, just as if the name - were found in the dcache. - -2. `vfs_open()` can fail with `-EOPENSTALE` if the cached information - wasn't quite current enough. Rather than restarting the lookup from - the top with `LOOKUP_REVAL` set, `lookup_open()` is called instead, - giving the filesystem a chance to resolve small inconsistencies. - If that doesn't work, only then is the lookup restarted from the top. +1. Rather than just finding the target file, ``do_last()`` needs to open + it. If the file was found in the dcache, then ``vfs_open()`` is used for + this. If not, then ``lookup_open()`` will either call ``atomic_open()`` (if + the filesystem provides it) to combine the final lookup with the open, or + will perform the separate ``lookup_real()`` and ``vfs_create()`` steps + directly. In the later case the actual "open" of this newly found or + created file will be performed by ``vfs_open()``, just as if the name + were found in the dcache. + +2. ``vfs_open()`` can fail with ``-EOPENSTALE`` if the cached information + wasn't quite current enough. Rather than restarting the lookup from + the top with ``LOOKUP_REVAL`` set, ``lookup_open()`` is called instead, + giving the filesystem a chance to resolve small inconsistencies. + If that doesn't work, only then is the lookup restarted from the top. 3. An open with O_CREAT **does** follow a symlink in the final component, - unlike other creation system calls (like `mkdir`). So the sequence: + unlike other creation system calls (like ``mkdir``). So the sequence:: - > ln -s bar /tmp/foo - > echo hello > /tmp/foo + ln -s bar /tmp/foo + echo hello > /tmp/foo - will create a file called `/tmp/bar`. This is not permitted if - `O_EXCL` is set but otherwise is handled for an O_CREAT open much - like for a non-creating open: `should_follow_link()` returns `1`, and - so does `do_last()` so that `trailing_symlink()` gets called and the - open process continues on the symlink that was found. + will create a file called ``/tmp/bar``. This is not permitted if + ``O_EXCL`` is set but otherwise is handled for an O_CREAT open much + like for a non-creating open: ``should_follow_link()`` returns ``1``, and + so does ``do_last()`` so that ``trailing_symlink()`` gets called and the + open process continues on the symlink that was found. Updating the access time ------------------------ @@ -1180,110 +1227,112 @@ footprints are best kept to a minimum. One other place where walking down a symlink can involve leaving footprints in a way that doesn't affect directories is in updating access times. In Unix (and Linux) every filesystem object has a "last accessed -time", or "`atime`". Passing through a directory to access a file +time", or "``atime``". Passing through a directory to access a file within is not considered to be an access for the purposes of -`atime`; only listing the contents of a directory can update its `atime`. -Symlinks are different it seems. Both reading a symlink (with `readlink()`) +``atime``; only listing the contents of a directory can update its ``atime``. +Symlinks are different it seems. Both reading a symlink (with ``readlink()``) and looking up a symlink on the way to some other destination can update the atime on that symlink. -[clearest statement]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_08 +.. _clearest statement: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_08 It is not clear why this is the case; POSIX has little to say on the -subject. The [clearest statement] is that, if a particular implementation +subject. The `clearest statement`_ is that, if a particular implementation updates a timestamp in a place not specified by POSIX, this must be documented "except that any changes caused by pathname resolution need not be documented". This seems to imply that POSIX doesn't really care about access-time updates during pathname lookup. -[Linux 1.3.87]: https://git.kernel.org/cgit/linux/kernel/git/history/history.git/diff/fs/ext2/symlink.c?id=f806c6db77b8eaa6e00dcfb6b567706feae8dbb8 +.. _Linux 1.3.87: https://git.kernel.org/cgit/linux/kernel/git/history/history.git/diff/fs/ext2/symlink.c?id=f806c6db77b8eaa6e00dcfb6b567706feae8dbb8 -An examination of history shows that prior to [Linux 1.3.87], the ext2 +An examination of history shows that prior to `Linux 1.3.87`_, the ext2 filesystem, at least, didn't update atime when following a link. Unfortunately we have no record of why that behavior was changed. In any case, access time must now be updated and that operation can be quite complex. Trying to stay in RCU-walk while doing it is best -avoided. Fortunately it is often permitted to skip the `atime` -update. Because `atime` updates cause performance problems in various -areas, Linux supports the `relatime` mount option, which generally -limits the updates of `atime` to once per day on files that aren't +avoided. Fortunately it is often permitted to skip the ``atime`` +update. Because ``atime`` updates cause performance problems in various +areas, Linux supports the ``relatime`` mount option, which generally +limits the updates of ``atime`` to once per day on files that aren't being changed (and symlinks never change once created). Even without -`relatime`, many filesystems record `atime` with a one-second +``relatime``, many filesystems record ``atime`` with a one-second granularity, so only one update per second is required. -It is easy to test if an `atime` update is needed while in RCU-walk +It is easy to test if an ``atime`` update is needed while in RCU-walk mode and, if it isn't, the update can be skipped and RCU-walk mode -continues. Only when an `atime` update is actually required does the +continues. Only when an ``atime`` update is actually required does the path walk drop down to REF-walk. All of this is handled in the -`get_link()` function. +``get_link()`` function. A few flags ----------- A suitable way to wrap up this tour of pathname walking is to list -the various flags that can be stored in the `nameidata` to guide the +the various flags that can be stored in the ``nameidata`` to guide the lookup process. Many of these are only meaningful on the final component, others reflect the current state of the pathname lookup. -And then there is `LOOKUP_EMPTY`, which doesn't fit conceptually with +And then there is ``LOOKUP_EMPTY``, which doesn't fit conceptually with the others. If this is not set, an empty pathname causes an error very early on. If it is set, empty pathnames are not considered to be an error. -### Global state flags ### +Global state flags +~~~~~~~~~~~~~~~~~~ -We have already met two global state flags: `LOOKUP_RCU` and -`LOOKUP_REVAL`. These select between one of three overall approaches +We have already met two global state flags: ``LOOKUP_RCU`` and +``LOOKUP_REVAL``. These select between one of three overall approaches to lookup: RCU-walk, REF-walk, and REF-walk with forced revalidation. -`LOOKUP_PARENT` indicates that the final component hasn't been reached +``LOOKUP_PARENT`` indicates that the final component hasn't been reached yet. This is primarily used to tell the audit subsystem the full context of a particular access being audited. -`LOOKUP_ROOT` indicates that the `root` field in the `nameidata` was +``LOOKUP_ROOT`` indicates that the ``root`` field in the ``nameidata`` was provided by the caller, so it shouldn't be released when it is no longer needed. -`LOOKUP_JUMPED` means that the current dentry was chosen not because +``LOOKUP_JUMPED`` means that the current dentry was chosen not because it had the right name but for some other reason. This happens when -following "`..`", following a symlink to `/`, crossing a mount point -or accessing a "`/proc/$PID/fd/$FD`" symlink. In this case the +following "``..``", following a symlink to ``/``, crossing a mount point +or accessing a "``/proc/$PID/fd/$FD``" symlink. In this case the filesystem has not been asked to revalidate the name (with -`d_revalidate()`). In such cases the inode may still need to be -revalidated, so `d_op->d_weak_revalidate()` is called if -`LOOKUP_JUMPED` is set when the look completes - which may be at the +``d_revalidate()``). In such cases the inode may still need to be +revalidated, so ``d_op->d_weak_revalidate()`` is called if +``LOOKUP_JUMPED`` is set when the look completes - which may be at the final component or, when creating, unlinking, or renaming, at the penultimate component. -### Final-component flags ### +Final-component flags +~~~~~~~~~~~~~~~~~~~~~ Some of these flags are only set when the final component is being considered. Others are only checked for when considering that final component. -`LOOKUP_AUTOMOUNT` ensures that, if the final component is an automount +``LOOKUP_AUTOMOUNT`` ensures that, if the final component is an automount point, then the mount is triggered. Some operations would trigger it -anyway, but operations like `stat()` deliberately don't. `statfs()` -needs to trigger the mount but otherwise behaves a lot like `stat()`, so -it sets `LOOKUP_AUTOMOUNT`, as does "`quotactl()`" and the handling of -"`mount --bind`". +anyway, but operations like ``stat()`` deliberately don't. ``statfs()`` +needs to trigger the mount but otherwise behaves a lot like ``stat()``, so +it sets ``LOOKUP_AUTOMOUNT``, as does "``quotactl()``" and the handling of +"``mount --bind``". -`LOOKUP_FOLLOW` has a similar function to `LOOKUP_AUTOMOUNT` but for +``LOOKUP_FOLLOW`` has a similar function to ``LOOKUP_AUTOMOUNT`` but for symlinks. Some system calls set or clear it implicitly, while -others have API flags such as `AT_SYMLINK_FOLLOW` and -`UMOUNT_NOFOLLOW` to control it. Its effect is similar to -`WALK_GET` that we already met, but it is used in a different way. +others have API flags such as ``AT_SYMLINK_FOLLOW`` and +``UMOUNT_NOFOLLOW`` to control it. Its effect is similar to +``WALK_GET`` that we already met, but it is used in a different way. -`LOOKUP_DIRECTORY` insists that the final component is a directory. +``LOOKUP_DIRECTORY`` insists that the final component is a directory. Various callers set this and it is also set when the final component is found to be followed by a slash. -Finally `LOOKUP_OPEN`, `LOOKUP_CREATE`, `LOOKUP_EXCL`, and -`LOOKUP_RENAME_TARGET` are not used directly by the VFS but are made -available to the filesystem and particularly the `->d_revalidate()` +Finally ``LOOKUP_OPEN``, ``LOOKUP_CREATE``, ``LOOKUP_EXCL``, and +``LOOKUP_RENAME_TARGET`` are not used directly by the VFS but are made +available to the filesystem and particularly the ``->d_revalidate()`` method. A filesystem can choose not to bother revalidating too hard if it knows that it will be asked to open or create the file soon. -These flags were previously useful for `->lookup()` too but with the -introduction of `->atomic_open()` they are less relevant there. +These flags were previously useful for ``->lookup()`` too but with the +introduction of ``->atomic_open()`` they are less relevant there. End of the road --------------- diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 12a5e6e693b6..66cad5c86171 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -125,6 +125,13 @@ process running on the system, which is named after the process ID (PID). The link self points to the process reading the file system. Each process subdirectory has the entries listed in Table 1-1. +Note that an open a file descriptor to /proc/<pid> or to any of its +contained files or subdirectories does not prevent <pid> being reused +for some other process in the event that <pid> exits. Operations on +open /proc/<pid> file descriptors corresponding to dead processes +never act on any new process that the kernel may, through chance, have +also assigned the process ID <pid>. Instead, operations on these FDs +usually fail with ESRCH. Table 1-1: Process specific entries in /proc .............................................................................. @@ -182,6 +189,7 @@ read the file /proc/PID/status: VmSwap: 0 kB HugetlbPages: 0 kB CoreDumping: 0 + THP_enabled: 1 Threads: 1 SigQ: 0/28578 SigPnd: 0000000000000000 @@ -193,8 +201,10 @@ read the file /proc/PID/status: CapPrm: 0000000000000000 CapEff: 0000000000000000 CapBnd: ffffffffffffffff + CapAmb: 0000000000000000 NoNewPrivs: 0 Seccomp: 0 + Speculation_Store_Bypass: thread vulnerable voluntary_ctxt_switches: 0 nonvoluntary_ctxt_switches: 1 @@ -214,7 +224,7 @@ asynchronous manner and the value may not be very precise. To see a precise snapshot of a moment, you can see /proc/<pid>/smaps file and scan page table. It's slow but very precise. -Table 1-2: Contents of the status files (as of 4.8) +Table 1-2: Contents of the status files (as of 4.19) .............................................................................. Field Content Name filename of the executable @@ -256,6 +266,8 @@ Table 1-2: Contents of the status files (as of 4.8) HugetlbPages size of hugetlb memory portions CoreDumping process's memory is currently being dumped (killing the process may lead to a corrupted core) + THP_enabled process is allowed to use THP (returns 0 when + PR_SET_THP_DISABLE is set on the process Threads number of threads SigQ number of signals queued/max. number for queue SigPnd bitmap of pending signals for the thread @@ -267,8 +279,10 @@ Table 1-2: Contents of the status files (as of 4.8) CapPrm bitmap of permitted capabilities CapEff bitmap of effective capabilities CapBnd bitmap of capabilities bounding set + CapAmb bitmap of ambient capabilities NoNewPrivs no_new_privs, like prctl(PR_GET_NO_NEW_PRIV, ...) Seccomp seccomp mode, like prctl(PR_GET_SECCOMP, ...) + Speculation_Store_Bypass speculative store bypass mitigation status Cpus_allowed mask of CPUs on which this process may run Cpus_allowed_list Same as previous, but in "list format" Mems_allowed mask of memory nodes allowed to this process @@ -425,6 +439,7 @@ SwapPss: 0 kB KernelPageSize: 4 kB MMUPageSize: 4 kB Locked: 0 kB +THPeligible: 0 VmFlags: rd ex mr mw me dw the first of these lines shows the same information as is displayed for the @@ -462,6 +477,8 @@ replaced by copy-on-write) part of the underlying shmem object out on swap. "SwapPss" shows proportional swap share of this mapping. Unlike "Swap", this does not take into account swapped out page of underlying shmem objects. "Locked" indicates whether the mapping is locked in memory or not. +"THPeligible" indicates whether the mapping is eligible for THP pages - 1 if +true, 0 otherwise. "VmFlags" field deserves a separate description. This member represents the kernel flags associated with the particular virtual memory area in two letter encoded @@ -496,7 +513,9 @@ manner. The codes are the following: Note that there is no guarantee that every flag and associated mnemonic will be present in all further kernel releases. Things get changed, the flags may -be vanished or the reverse -- new added. +be vanished or the reverse -- new added. Interpretation of their meaning +might change in future as well. So each consumer of these flags has to +follow each specific kernel version for the exact semantic. This file is only present if the CONFIG_MMU kernel configuration option is enabled. diff --git a/Documentation/filesystems/qnx6.txt b/Documentation/filesystems/qnx6.txt index 4f3d6a882bdc..48ea68f15845 100644 --- a/Documentation/filesystems/qnx6.txt +++ b/Documentation/filesystems/qnx6.txt @@ -87,7 +87,7 @@ addressed with 16 direct blocks. For more than 16 blocks an indirect addressing in form of another tree is used. (scheme is the same as the one used for the superblock root nodes) -The filesize is stored 64bit. Inode counting starts with 1. (whilst long +The filesize is stored 64bit. Inode counting starts with 1. (while long filename inodes start with 0) Directories @@ -155,7 +155,7 @@ Then userspace. The requirement for a static, fixed preallocated system area comes from how qnx6fs deals with writes. Each superblock got it's own half of the system area. So superblock #1 -always uses blocks from the lower half whilst superblock #2 just writes to +always uses blocks from the lower half while superblock #2 just writes to blocks represented by the upper half bitmap system area bits. Bitmap blocks, Inode blocks and indirect addressing blocks for those two diff --git a/Documentation/filesystems/spufs.txt b/Documentation/filesystems/spufs.txt index 1343d118a9b2..eb9e3aa63026 100644 --- a/Documentation/filesystems/spufs.txt +++ b/Documentation/filesystems/spufs.txt @@ -452,7 +452,7 @@ RETURN VALUE ERRORS - EACCESS + EACCES The current user does not have write access on the spufs mount point. diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 5f71a252e2e0..8dc8e9c2913f 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -1131,7 +1131,7 @@ struct dentry_operations { d_manage: called to allow the filesystem to manage the transition from a dentry (optional). This allows autofs, for example, to hold up clients - waiting to explore behind a 'mountpoint' whilst letting the daemon go + waiting to explore behind a 'mountpoint' while letting the daemon go past and construct the subtree there. 0 should be returned to let the calling process continue. -EISDIR can be returned to tell pathwalk to use this directory as an ordinary directory and to ignore anything diff --git a/Documentation/filesystems/xfs-self-describing-metadata.txt b/Documentation/filesystems/xfs-self-describing-metadata.txt index 05aa455163e3..68604e67a495 100644 --- a/Documentation/filesystems/xfs-self-describing-metadata.txt +++ b/Documentation/filesystems/xfs-self-describing-metadata.txt @@ -110,7 +110,7 @@ owner field in the metadata object, we can immediately do top down validation to determine the scope of the problem. Different types of metadata have different owner identifiers. For example, -directory, attribute and extent tree blocks are all owned by an inode, whilst +directory, attribute and extent tree blocks are all owned by an inode, while freespace btree blocks are owned by an allocation group. Hence the size and contents of the owner field are determined by the type of metadata object we are looking at. The owner information can also identify misplaced writes (e.g. diff --git a/Documentation/filesystems/xfs.txt b/Documentation/filesystems/xfs.txt index a9ae82fb9d13..9ccfd1bc6201 100644 --- a/Documentation/filesystems/xfs.txt +++ b/Documentation/filesystems/xfs.txt @@ -417,7 +417,7 @@ level directory: filesystem from ever unmounting fully in the case of "retry forever" handler configurations. - Note: there is no guarantee that fail_at_unmount can be set whilst an + Note: there is no guarantee that fail_at_unmount can be set while an unmount is in progress. It is possible that the sysfs entries are removed by the unmounting filesystem before a "retry forever" error handler configuration causes unmount to hang, and hence the filesystem diff --git a/Documentation/gpu/drm-uapi.rst b/Documentation/gpu/drm-uapi.rst index 4b4bf2c5eac5..a752aa561ea4 100644 --- a/Documentation/gpu/drm-uapi.rst +++ b/Documentation/gpu/drm-uapi.rst @@ -190,11 +190,11 @@ ENOSPC: Simply running out of kernel/system memory is signalled through ENOMEM. -EPERM/EACCESS: +EPERM/EACCES: Returned for an operation that is valid, but needs more privileges. E.g. root-only or much more common, DRM master-only operations return this when when called by unpriviledged clients. There's no clear - difference between EACCESS and EPERM. + difference between EACCES and EPERM. ENODEV: The device is not (yet) present or fully initialized. diff --git a/Documentation/hwmon/adm1275 b/Documentation/hwmon/adm1275 index 39033538eb03..5e277b0d91ce 100644 --- a/Documentation/hwmon/adm1275 +++ b/Documentation/hwmon/adm1275 @@ -58,6 +58,9 @@ The ADM1075, unlike many other PMBus devices, does not support internal voltage or current scaling. Reported voltages, currents, and power are raw measurements, and will typically have to be scaled. +The shunt value in micro-ohms can be set via device tree at compile-time. Please +refer to the Documentation/devicetree/bindings/hwmon/adm1275.txt for bindings +if the device tree is used. Platform data support --------------------- diff --git a/Documentation/hwmon/adt7475 b/Documentation/hwmon/adt7475 index 09d73a10644c..01b46b290532 100644 --- a/Documentation/hwmon/adt7475 +++ b/Documentation/hwmon/adt7475 @@ -79,6 +79,18 @@ ADT7490: * 2 GPIO pins (not implemented) * system acoustics optimizations (not implemented) +Sysfs Mapping +------------- + + ADT7490 ADT7476 ADT7475 ADT7473 + ------- ------- ------- ------- +in0 2.5VIN (22) 2.5VIN (22) - - +in1 VCCP (23) VCCP (23) VCCP (14) VCCP (14) +in2 VCC (4) VCC (4) VCC (4) VCC (3) +in3 5VIN (20) 5VIN (20) +in4 12VIN (21) 12VIN (21) +in5 VTT (8) + Special Features ---------------- diff --git a/Documentation/hwmon/hwmon-kernel-api.txt b/Documentation/hwmon/hwmon-kernel-api.txt index eb7a78aebb38..8bdefb41be30 100644 --- a/Documentation/hwmon/hwmon-kernel-api.txt +++ b/Documentation/hwmon/hwmon-kernel-api.txt @@ -299,17 +299,25 @@ functions is used. The header file linux/hwmon-sysfs.h provides a number of useful macros to declare and use hardware monitoring sysfs attributes. -In many cases, you can use the exsting define DEVICE_ATTR to declare such -attributes. This is feasible if an attribute has no additional context. However, -in many cases there will be additional information such as a sensor index which -will need to be passed to the sysfs attribute handling function. +In many cases, you can use the exsting define DEVICE_ATTR or its variants +DEVICE_ATTR_{RW,RO,WO} to declare such attributes. This is feasible if an +attribute has no additional context. However, in many cases there will be +additional information such as a sensor index which will need to be passed +to the sysfs attribute handling function. SENSOR_DEVICE_ATTR and SENSOR_DEVICE_ATTR_2 can be used to define attributes which need such additional context information. SENSOR_DEVICE_ATTR requires one additional argument, SENSOR_DEVICE_ATTR_2 requires two. -SENSOR_DEVICE_ATTR defines a struct sensor_device_attribute variable. -This structure has the following fields. +Simplified variants of SENSOR_DEVICE_ATTR and SENSOR_DEVICE_ATTR_2 are available +and should be used if standard attribute permissions and function names are +feasible. Standard permissions are 0644 for SENSOR_DEVICE_ATTR[_2]_RW, +0444 for SENSOR_DEVICE_ATTR[_2]_RO, and 0200 for SENSOR_DEVICE_ATTR[_2]_WO. +Standard functions, similar to DEVICE_ATTR_{RW,RO,WO}, have _show and _store +appended to the provided function name. + +SENSOR_DEVICE_ATTR and its variants define a struct sensor_device_attribute +variable. This structure has the following fields. struct sensor_device_attribute { struct device_attribute dev_attr; @@ -320,8 +328,8 @@ You can use to_sensor_dev_attr to get the pointer to this structure from the attribute read or write function. Its parameter is the device to which the attribute is attached. -SENSOR_DEVICE_ATTR_2 defines a struct sensor_device_attribute_2 variable, -which is defined as follows. +SENSOR_DEVICE_ATTR_2 and its variants define a struct sensor_device_attribute_2 +variable, which is defined as follows. struct sensor_device_attribute_2 { struct device_attribute dev_attr; diff --git a/Documentation/hwmon/ina2xx b/Documentation/hwmon/ina2xx index b8df81f6d6bc..0f36c021192d 100644 --- a/Documentation/hwmon/ina2xx +++ b/Documentation/hwmon/ina2xx @@ -62,3 +62,18 @@ bus and shunt voltage conversion times multiplied by the averaging rate. We don't touch the conversion times and only modify the number of averages. The lower limit of the update_interval is 2 ms, the upper limit is 2253 ms. The actual programmed interval may vary from the desired value. + +General sysfs entries +------------- + +in0_input Shunt voltage(mV) channel +in1_input Bus voltage(mV) channel +curr1_input Current(mA) measurement channel +power1_input Power(uW) measurement channel +shunt_resistor Shunt resistance(uOhm) channel + +Sysfs entries for ina226, ina230 and ina231 only +------------- + +update_interval data conversion time; affects number of samples used + to average results for shunt and bus voltages. diff --git a/Documentation/hwmon/lm75 b/Documentation/hwmon/lm75 index 2f1120f88c16..010583608f12 100644 --- a/Documentation/hwmon/lm75 +++ b/Documentation/hwmon/lm75 @@ -42,6 +42,11 @@ Supported chips: Addresses scanned: none Datasheet: Publicly available at the ST website http://www.st.com/internet/analog/product/121769.jsp + * ST Microelectronics STLM75 + Prefix: 'stlm75' + Addresses scanned: none + Datasheet: Publicly available at the ST website + https://www.st.com/resource/en/datasheet/stlm75.pdf * Texas Instruments TMP100, TMP101, TMP105, TMP112, TMP75, TMP75C, TMP175, TMP275 Prefixes: 'tmp100', 'tmp101', 'tmp105', 'tmp112', 'tmp175', 'tmp75', 'tmp75c', 'tmp275' Addresses scanned: none diff --git a/Documentation/hwmon/occ b/Documentation/hwmon/occ new file mode 100644 index 000000000000..e787596e03fe --- /dev/null +++ b/Documentation/hwmon/occ @@ -0,0 +1,112 @@ +Kernel driver occ-hwmon +======================= + +Supported chips: + * POWER8 + * POWER9 + +Author: Eddie James <eajames@linux.ibm.com> + +Description +----------- + +This driver supports hardware monitoring for the On-Chip Controller (OCC) +embedded on POWER processors. The OCC is a device that collects and aggregates +sensor data from the processor and the system. The OCC can provide the raw +sensor data as well as perform thermal and power management on the system. + +The P8 version of this driver is a client driver of I2C. It may be probed +manually if an "ibm,p8-occ-hwmon" compatible device is found under the +appropriate I2C bus node in the device-tree. + +The P9 version of this driver is a client driver of the FSI-based OCC driver. +It will be probed automatically by the FSI-based OCC driver. + +Sysfs entries +------------- + +The following attributes are supported. All attributes are read-only unless +specified. + +The OCC sensor ID is an integer that represents the unique identifier of the +sensor with respect to the OCC. For example, a temperature sensor for the third +DIMM slot in the system may have a sensor ID of 7. This mapping is unavailable +to the device driver, which must therefore export the sensor ID as-is. + +Some entries are only present with certain OCC sensor versions or only on +certain OCCs in the system. The version number is not exported to the user +but can be inferred. + +temp[1-n]_label OCC sensor ID. +[with temperature sensor version 1] + temp[1-n]_input Measured temperature of the component in millidegrees + Celsius. +[with temperature sensor version >= 2] + temp[1-n]_type The FRU (Field Replaceable Unit) type + (represented by an integer) for the component + that this sensor measures. + temp[1-n]_fault Temperature sensor fault boolean; 1 to indicate + that a fault is present or 0 to indicate that + no fault is present. + [with type == 3 (FRU type is VRM)] + temp[1-n]_alarm VRM temperature alarm boolean; 1 to indicate + alarm, 0 to indicate no alarm + [else] + temp[1-n]_input Measured temperature of the component in + millidegrees Celsius. + +freq[1-n]_label OCC sensor ID. +freq[1-n]_input Measured frequency of the component in MHz. + +power[1-n]_input Latest measured power reading of the component in + microwatts. +power[1-n]_average Average power of the component in microwatts. +power[1-n]_average_interval The amount of time over which the power average + was taken in microseconds. +[with power sensor version < 2] + power[1-n]_label OCC sensor ID. +[with power sensor version >= 2] + power[1-n]_label OCC sensor ID + function ID + channel in the form + of a string, delimited by underscores, i.e. "0_15_1". + Both the function ID and channel are integers that + further identify the power sensor. +[with power sensor version 0xa0] + power[1-n]_label OCC sensor ID + sensor type in the form of a string, + delimited by an underscore, i.e. "0_system". Sensor + type will be one of "system", "proc", "vdd" or "vdn". + For this sensor version, OCC sensor ID will be the same + for all power sensors. +[present only on "master" OCC; represents the whole system power; only one of + this type of power sensor will be present] + power[1-n]_label "system" + power[1-n]_input Latest system output power in microwatts. + power[1-n]_cap Current system power cap in microwatts. + power[1-n]_cap_not_redundant System power cap in microwatts when + there is not redundant power. + power[1-n]_cap_max Maximum power cap that the OCC can enforce in + microwatts. + power[1-n]_cap_min Minimum power cap that the OCC can enforce in + microwatts. + power[1-n]_cap_user The power cap set by the user, in microwatts. + This attribute will return 0 if no user power + cap has been set. This attribute is read-write, + but writing any precision below watts will be + ignored, i.e. requesting a power cap of + 500900000 microwatts will result in a power cap + request of 500 watts. + [with caps sensor version > 1] + power[1-n]_cap_user_source Indicates how the user power cap was + set. This is an integer that maps to + system or firmware components that can + set the user power cap. + +The following "extn" sensors are exported as a way for the OCC to provide data +that doesn't fit anywhere else. The meaning of these sensors is entirely +dependent on their data, and cannot be statically defined. + +extn[1-n]_label ASCII ID or OCC sensor ID. +extn[1-n]_flags This is one byte hexadecimal value. Bit 7 indicates the + type of the label attribute; 1 for sensor ID, 0 for + ASCII ID. Other bits are reserved. +extn[1-n]_input 6 bytes of hexadecimal data, with a meaning defined by + the sensor ID. diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt index af6f6ba1fe80..c9558146ac58 100644 --- a/Documentation/ioctl/ioctl-number.txt +++ b/Documentation/ioctl/ioctl-number.txt @@ -79,6 +79,7 @@ Code Seq#(hex) Include File Comments 0x1b all InfiniBand Subsystem <http://infiniband.sourceforge.net/> 0x20 all drivers/cdrom/cm206.h 0x22 all scsi/sg.h +'!' 00-1F uapi/linux/seccomp.h '#' 00-3F IEEE 1394 Subsystem Block for the entire subsystem '$' 00-0F linux/perf_counter.h, linux/perf_event.h '%' 00-0F include/uapi/linux/stm.h diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt index 8390c360d4b3..c9e3d93e7a89 100644 --- a/Documentation/kbuild/kbuild.txt +++ b/Documentation/kbuild/kbuild.txt @@ -81,12 +81,7 @@ KBUILD_EXTMOD -------------------------------------------------- Set the directory to look for the kernel source when building external modules. -The directory can be specified in several ways: -1) Use "M=..." on the command line -2) Environment variable KBUILD_EXTMOD -3) Environment variable SUBDIRS -The possibilities are listed in the order they take precedence. -Using "M=..." will always override the others. +Setting "M=..." takes precedence over KBUILD_EXTMOD. KBUILD_OUTPUT -------------------------------------------------- diff --git a/Documentation/kobject.txt b/Documentation/kobject.txt index fc9485d79061..ff4c25098119 100644 --- a/Documentation/kobject.txt +++ b/Documentation/kobject.txt @@ -279,10 +279,14 @@ such a method has a form like:: One important point cannot be overstated: every kobject must have a release() method, and the kobject must persist (in a consistent state) until that method is called. If these constraints are not met, the code is -flawed. Note that the kernel will warn you if you forget to provide a +flawed. Note that the kernel will warn you if you forget to provide a release() method. Do not try to get rid of this warning by providing an -"empty" release function; you will be mocked mercilessly by the kobject -maintainer if you attempt this. +"empty" release function. + +If all your cleanup function needs to do is call kfree(), then you must +create a wrapper function which uses container_of() to upcast to the correct +type (as shown in the example above) and then calls kfree() on the overall +structure. Note, the name of the kobject is available in the release function, but it must NOT be changed within this callback. Otherwise there will be a memory diff --git a/Documentation/leds/leds-class.txt b/Documentation/leds/leds-class.txt index 836cb16d6f09..8b39cc6b03ee 100644 --- a/Documentation/leds/leds-class.txt +++ b/Documentation/leds/leds-class.txt @@ -15,7 +15,7 @@ existing subsystems with minimal additional code. Examples are the disk-activity nand-disk and sharpsl-charge triggers. With led triggers disabled, the code optimises away. -Complex triggers whilst available to all LEDs have LED specific +Complex triggers while available to all LEDs have LED specific parameters and work on a per LED basis. The timer trigger is an example. The timer trigger will periodically change the LED brightness between LED_OFF and the current brightness setting. The "on" and "off" time can diff --git a/Documentation/media/uapi/v4l/extended-controls.rst b/Documentation/media/uapi/v4l/extended-controls.rst index c471408d9bf9..286a2dd7ec36 100644 --- a/Documentation/media/uapi/v4l/extended-controls.rst +++ b/Documentation/media/uapi/v4l/extended-controls.rst @@ -4003,7 +4003,7 @@ demodulator. It receives radio frequency (RF) from the antenna and converts that received signal to lower intermediate frequency (IF) or baseband frequency (BB). Tuners that could do baseband output are often called Zero-IF tuners. Older tuners were typically simple PLL tuners -inside a metal box, whilst newer ones are highly integrated chips +inside a metal box, while newer ones are highly integrated chips without a metal box "silicon tuners". These controls are mostly applicable for new feature rich silicon tuners, just because older tuners does not have much adjustable features. diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index c1d913944ad8..1c22b21ae922 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -587,7 +587,7 @@ leading to the following situation: (Q == &B) and (D == 2) ???? -Whilst this may seem like a failure of coherency or causality maintenance, it +While this may seem like a failure of coherency or causality maintenance, it isn't, and this behaviour can be observed on certain real CPUs (such as the DEC Alpha). @@ -2008,7 +2008,7 @@ for each construct. These operations all imply certain barriers: Certain locking variants of the ACQUIRE operation may fail, either due to being unable to get the lock immediately, or due to receiving an unblocked - signal whilst asleep waiting for the lock to become available. Failed + signal while asleep waiting for the lock to become available. Failed locks do not imply any sort of barrier. [!] Note: one of the consequences of lock ACQUIREs and RELEASEs being only @@ -2508,7 +2508,7 @@ CPU, that CPU's dependency ordering logic will take care of everything else. ATOMIC OPERATIONS ----------------- -Whilst they are technically interprocessor interaction considerations, atomic +While they are technically interprocessor interaction considerations, atomic operations are noted specially as some of them imply full memory barriers and some don't, but they're very heavily relied on as a group throughout the kernel. @@ -2531,7 +2531,7 @@ the device to malfunction. Inside of the Linux kernel, I/O should be done through the appropriate accessor routines - such as inb() or writel() - which know how to make such accesses -appropriately sequential. Whilst this, for the most part, renders the explicit +appropriately sequential. While this, for the most part, renders the explicit use of memory barriers unnecessary, there are a couple of situations where they might be needed: @@ -2555,7 +2555,7 @@ access the device. This may be alleviated - at least in part - by disabling local interrupts (a form of locking), such that the critical operations are all contained within -the interrupt-disabled section in the driver. Whilst the driver's interrupt +the interrupt-disabled section in the driver. While the driver's interrupt routine is executing, the driver's core may not run on the same CPU, and its interrupt is not permitted to happen again until the current interrupt has been handled, thus the interrupt handler does not need to lock against that. @@ -2763,7 +2763,7 @@ CACHE COHERENCY Life isn't quite as simple as it may appear above, however: for while the caches are expected to be coherent, there's no guarantee that that coherency -will be ordered. This means that whilst changes made on one CPU will +will be ordered. This means that while changes made on one CPU will eventually become visible on all CPUs, there's no guarantee that they will become apparent in the same order on those other CPUs. @@ -2799,7 +2799,7 @@ Imagine the system has the following properties: (*) an even-numbered cache line may be in cache B, cache D or it may still be resident in memory; - (*) whilst the CPU core is interrogating one cache, the other cache may be + (*) while the CPU core is interrogating one cache, the other cache may be making use of the bus to access the rest of the system - perhaps to displace a dirty cacheline or to do a speculative load; @@ -2835,7 +2835,7 @@ now imagine that the second CPU wants to read those values: x = *q; The above pair of reads may then fail to happen in the expected order, as the -cacheline holding p may get updated in one of the second CPU's caches whilst +cacheline holding p may get updated in one of the second CPU's caches while the update to the cacheline holding v is delayed in the other of the second CPU's caches by some other cache event: @@ -2855,7 +2855,7 @@ CPU's caches by some other cache event: <C:unbusy> <C:commit v=2> -Basically, whilst both cachelines will be updated on CPU 2 eventually, there's +Basically, while both cachelines will be updated on CPU 2 eventually, there's no guarantee that, without intervention, the order of update will be the same as that committed on CPU 1. @@ -2885,7 +2885,7 @@ coherency queue before processing any further requests: This sort of problem can be encountered on DEC Alpha processors as they have a split cache that improves performance by making better use of the data bus. -Whilst most CPUs do imply a data dependency barrier on the read when a memory +While most CPUs do imply a data dependency barrier on the read when a memory access depends on a read, not all do, so it may not be relied on. Other CPUs may also have split caches, but must coordinate between the various @@ -2974,7 +2974,7 @@ assumption doesn't hold because: thus cutting down on transaction setup costs (memory and PCI devices may both be able to do this); and - (*) the CPU's data cache may affect the ordering, and whilst cache-coherency + (*) the CPU's data cache may affect the ordering, and while cache-coherency mechanisms may alleviate this - once the store has actually hit the cache - there's no guarantee that the coherency management will be propagated in order to other CPUs. diff --git a/Documentation/networking/3c509.txt b/Documentation/networking/device_drivers/3com/3c509.txt index fbf722e15ac3..fbf722e15ac3 100644 --- a/Documentation/networking/3c509.txt +++ b/Documentation/networking/device_drivers/3com/3c509.txt diff --git a/Documentation/networking/vortex.txt b/Documentation/networking/device_drivers/3com/vortex.txt index ad3dead052a4..587f3fcfbcae 100644 --- a/Documentation/networking/vortex.txt +++ b/Documentation/networking/device_drivers/3com/vortex.txt @@ -1,4 +1,4 @@ -Documentation/networking/vortex.txt +Documentation/networking/device_drivers/3com/vortex.txt Andrew Morton 30 April 2000 diff --git a/Documentation/networking/ena.txt b/Documentation/networking/device_drivers/amazon/ena.txt index 2b4b6f57e549..2b4b6f57e549 100644 --- a/Documentation/networking/ena.txt +++ b/Documentation/networking/device_drivers/amazon/ena.txt diff --git a/Documentation/networking/cxgb.txt b/Documentation/networking/device_drivers/chelsio/cxgb.txt index 20a887615c4a..20a887615c4a 100644 --- a/Documentation/networking/cxgb.txt +++ b/Documentation/networking/device_drivers/chelsio/cxgb.txt diff --git a/Documentation/networking/cs89x0.txt b/Documentation/networking/device_drivers/cirrus/cs89x0.txt index 0e190180eec8..0e190180eec8 100644 --- a/Documentation/networking/cs89x0.txt +++ b/Documentation/networking/device_drivers/cirrus/cs89x0.txt diff --git a/Documentation/networking/dm9000.txt b/Documentation/networking/device_drivers/davicom/dm9000.txt index 5552e2e575c5..5552e2e575c5 100644 --- a/Documentation/networking/dm9000.txt +++ b/Documentation/networking/device_drivers/davicom/dm9000.txt diff --git a/Documentation/networking/de4x5.txt b/Documentation/networking/device_drivers/dec/de4x5.txt index c8e4ca9b2c3e..452aac58341d 100644 --- a/Documentation/networking/de4x5.txt +++ b/Documentation/networking/device_drivers/dec/de4x5.txt @@ -84,7 +84,7 @@ Automedia detection is included so that in principle you can disconnect from, e.g. TP, reconnect to BNC and things will still work (after a - pause whilst the driver figures out where its media went). My tests + pause while the driver figures out where its media went). My tests using ping showed that it appears to work.... By default, the driver will now autodetect any DECchip based card. diff --git a/Documentation/networking/dmfe.txt b/Documentation/networking/device_drivers/dec/dmfe.txt index 25320bf19c86..25320bf19c86 100644 --- a/Documentation/networking/dmfe.txt +++ b/Documentation/networking/device_drivers/dec/dmfe.txt diff --git a/Documentation/networking/dl2k.txt b/Documentation/networking/device_drivers/dlink/dl2k.txt index cba74f7a3abc..cba74f7a3abc 100644 --- a/Documentation/networking/dl2k.txt +++ b/Documentation/networking/device_drivers/dlink/dl2k.txt diff --git a/Documentation/networking/dpaa.txt b/Documentation/networking/device_drivers/freescale/dpaa.txt index f88194f71c54..f88194f71c54 100644 --- a/Documentation/networking/dpaa.txt +++ b/Documentation/networking/device_drivers/freescale/dpaa.txt diff --git a/Documentation/networking/dpaa2/dpio-driver.rst b/Documentation/networking/device_drivers/freescale/dpaa2/dpio-driver.rst index 13588104161b..a188466b6698 100644 --- a/Documentation/networking/dpaa2/dpio-driver.rst +++ b/Documentation/networking/device_drivers/freescale/dpaa2/dpio-driver.rst @@ -19,8 +19,8 @@ pool management for network interfaces. This document provides an overview the Linux DPIO driver, its subcomponents, and its APIs. -See Documentation/networking/dpaa2/overview.rst for a general overview of DPAA2 -and the general DPAA2 driver architecture in Linux. +See Documentation/networking/device_drivers/freescale/dpaa2/overview.rst for +a general overview of DPAA2 and the general DPAA2 driver architecture in Linux. Driver Overview --------------- diff --git a/Documentation/networking/dpaa2/ethernet-driver.rst b/Documentation/networking/device_drivers/freescale/dpaa2/ethernet-driver.rst index 90ec940749e8..cb4c9a0c5a17 100644 --- a/Documentation/networking/dpaa2/ethernet-driver.rst +++ b/Documentation/networking/device_drivers/freescale/dpaa2/ethernet-driver.rst @@ -33,7 +33,7 @@ hardware resources, like queues, do not have a corresponding MC object and are treated as internal resources of other objects. For a more detailed description of the DPAA2 architecture and its object -abstractions see *Documentation/networking/dpaa2/overview.rst*. +abstractions see *Documentation/networking/device_drivers/freescale/dpaa2/overview.rst*. Each Linux net device is built on top of a Datapath Network Interface (DPNI) object and uses Buffer Pools (DPBPs), I/O Portals (DPIOs) and Concentrators diff --git a/Documentation/networking/dpaa2/index.rst b/Documentation/networking/device_drivers/freescale/dpaa2/index.rst index 67bd87fe6c53..67bd87fe6c53 100644 --- a/Documentation/networking/dpaa2/index.rst +++ b/Documentation/networking/device_drivers/freescale/dpaa2/index.rst diff --git a/Documentation/networking/dpaa2/overview.rst b/Documentation/networking/device_drivers/freescale/dpaa2/overview.rst index d638b5a8aadd..d638b5a8aadd 100644 --- a/Documentation/networking/dpaa2/overview.rst +++ b/Documentation/networking/device_drivers/freescale/dpaa2/overview.rst diff --git a/Documentation/networking/gianfar.txt b/Documentation/networking/device_drivers/freescale/gianfar.txt index ba1daea7f2e4..ba1daea7f2e4 100644 --- a/Documentation/networking/gianfar.txt +++ b/Documentation/networking/device_drivers/freescale/gianfar.txt diff --git a/Documentation/networking/e100.rst b/Documentation/networking/device_drivers/intel/e100.rst index 5e2839b4ec92..5e2839b4ec92 100644 --- a/Documentation/networking/e100.rst +++ b/Documentation/networking/device_drivers/intel/e100.rst diff --git a/Documentation/networking/e1000.rst b/Documentation/networking/device_drivers/intel/e1000.rst index 6379d4d20771..6379d4d20771 100644 --- a/Documentation/networking/e1000.rst +++ b/Documentation/networking/device_drivers/intel/e1000.rst diff --git a/Documentation/networking/e1000e.rst b/Documentation/networking/device_drivers/intel/e1000e.rst index 33554e5416c5..33554e5416c5 100644 --- a/Documentation/networking/e1000e.rst +++ b/Documentation/networking/device_drivers/intel/e1000e.rst diff --git a/Documentation/networking/fm10k.rst b/Documentation/networking/device_drivers/intel/fm10k.rst index bf5e5942f28d..bf5e5942f28d 100644 --- a/Documentation/networking/fm10k.rst +++ b/Documentation/networking/device_drivers/intel/fm10k.rst diff --git a/Documentation/networking/i40e.rst b/Documentation/networking/device_drivers/intel/i40e.rst index 0cc16c525d10..0cc16c525d10 100644 --- a/Documentation/networking/i40e.rst +++ b/Documentation/networking/device_drivers/intel/i40e.rst diff --git a/Documentation/networking/iavf.rst b/Documentation/networking/device_drivers/intel/iavf.rst index f8b42b64eb28..f8b42b64eb28 100644 --- a/Documentation/networking/iavf.rst +++ b/Documentation/networking/device_drivers/intel/iavf.rst diff --git a/Documentation/networking/ice.rst b/Documentation/networking/device_drivers/intel/ice.rst index 4d118b827bbb..4d118b827bbb 100644 --- a/Documentation/networking/ice.rst +++ b/Documentation/networking/device_drivers/intel/ice.rst diff --git a/Documentation/networking/igb.rst b/Documentation/networking/device_drivers/intel/igb.rst index ba16b86d5593..e87a4a72ea2d 100644 --- a/Documentation/networking/igb.rst +++ b/Documentation/networking/device_drivers/intel/igb.rst @@ -177,6 +177,25 @@ rate limit using the IProute2 tool. Download the latest version of the IProute2 tool from Sourceforge if your version does not have all the features you require. +Credit Based Shaper (Qav Mode) +------------------------------ +When enabling the CBS qdisc in the hardware offload mode, traffic shaping using +the CBS (described in the IEEE 802.1Q-2018 Section 8.6.8.2 and discussed in the +Annex L) algorithm will run in the i210 controller, so it's more accurate and +uses less CPU. + +When using offloaded CBS, and the traffic rate obeys the configured rate +(doesn't go above it), CBS should have little to no effect in the latency. + +The offloaded version of the algorithm has some limits, caused by how the idle +slope is expressed in the adapter's registers. It can only represent idle slopes +in 16.38431 kbps units, which means that if a idle slope of 2576kbps is +requested, the controller will be configured to use a idle slope of ~2589 kbps, +because the driver rounds the value up. For more details, see the comments on +:c:func:`igb_config_tx_modes()`. + +NOTE: This feature is exclusive to i210 models. + Support ======= diff --git a/Documentation/networking/igbvf.rst b/Documentation/networking/device_drivers/intel/igbvf.rst index a8a9ffa4f8d3..a8a9ffa4f8d3 100644 --- a/Documentation/networking/igbvf.rst +++ b/Documentation/networking/device_drivers/intel/igbvf.rst diff --git a/Documentation/networking/README.ipw2100 b/Documentation/networking/device_drivers/intel/ipw2100.txt index 6f85e1d06031..6f85e1d06031 100644 --- a/Documentation/networking/README.ipw2100 +++ b/Documentation/networking/device_drivers/intel/ipw2100.txt diff --git a/Documentation/networking/README.ipw2200 b/Documentation/networking/device_drivers/intel/ipw2200.txt index b7658bed4906..b7658bed4906 100644 --- a/Documentation/networking/README.ipw2200 +++ b/Documentation/networking/device_drivers/intel/ipw2200.txt diff --git a/Documentation/networking/ixgb.rst b/Documentation/networking/device_drivers/intel/ixgb.rst index 8bd80e27843d..8bd80e27843d 100644 --- a/Documentation/networking/ixgb.rst +++ b/Documentation/networking/device_drivers/intel/ixgb.rst diff --git a/Documentation/networking/ixgbe.rst b/Documentation/networking/device_drivers/intel/ixgbe.rst index 725fc697fd8f..86d887a63606 100644 --- a/Documentation/networking/ixgbe.rst +++ b/Documentation/networking/device_drivers/intel/ixgbe.rst @@ -501,6 +501,19 @@ NOTE: This feature can be disabled for a specific Virtual Function (VF):: ip link set <pf dev> vf <vf id> spoofchk {off|on} +IPsec Offload +------------- +The ixgbe driver supports IPsec Hardware Offload. When creating Security +Associations with "ip xfrm ..." the 'offload' tag option can be used to +register the IPsec SA with the driver in order to get higher throughput in +the secure communications. + +The offload is also supported for ixgbe's VFs, but the VF must be set as +'trusted' and the support must be enabled with:: + + ethtool --set-priv-flags eth<x> vf-ipsec on + ip link set eth<x> vf <y> trust on + Known Issues/Troubleshooting ============================ diff --git a/Documentation/networking/ixgbevf.rst b/Documentation/networking/device_drivers/intel/ixgbevf.rst index 56cde6366c2f..56cde6366c2f 100644 --- a/Documentation/networking/ixgbevf.rst +++ b/Documentation/networking/device_drivers/intel/ixgbevf.rst diff --git a/Documentation/networking/netvsc.txt b/Documentation/networking/device_drivers/microsoft/netvsc.txt index 3bfa635bbbd5..3bfa635bbbd5 100644 --- a/Documentation/networking/netvsc.txt +++ b/Documentation/networking/device_drivers/microsoft/netvsc.txt diff --git a/Documentation/networking/s2io.txt b/Documentation/networking/device_drivers/neterion/s2io.txt index 0362a42f7cf4..0362a42f7cf4 100644 --- a/Documentation/networking/s2io.txt +++ b/Documentation/networking/device_drivers/neterion/s2io.txt diff --git a/Documentation/networking/vxge.txt b/Documentation/networking/device_drivers/neterion/vxge.txt index abfec245f97c..abfec245f97c 100644 --- a/Documentation/networking/vxge.txt +++ b/Documentation/networking/device_drivers/neterion/vxge.txt diff --git a/Documentation/networking/LICENSE.qla3xxx b/Documentation/networking/device_drivers/qlogic/LICENSE.qla3xxx index 2f2077e34d81..2f2077e34d81 100644 --- a/Documentation/networking/LICENSE.qla3xxx +++ b/Documentation/networking/device_drivers/qlogic/LICENSE.qla3xxx diff --git a/Documentation/networking/LICENSE.qlcnic b/Documentation/networking/device_drivers/qlogic/LICENSE.qlcnic index 2ae3b64983ab..2ae3b64983ab 100644 --- a/Documentation/networking/LICENSE.qlcnic +++ b/Documentation/networking/device_drivers/qlogic/LICENSE.qlcnic diff --git a/Documentation/networking/LICENSE.qlge b/Documentation/networking/device_drivers/qlogic/LICENSE.qlge index ce64e4d15b21..ce64e4d15b21 100644 --- a/Documentation/networking/LICENSE.qlge +++ b/Documentation/networking/device_drivers/qlogic/LICENSE.qlge diff --git a/Documentation/networking/rmnet.txt b/Documentation/networking/device_drivers/qualcomm/rmnet.txt index 6b341eaf2062..6b341eaf2062 100644 --- a/Documentation/networking/rmnet.txt +++ b/Documentation/networking/device_drivers/qualcomm/rmnet.txt diff --git a/Documentation/networking/README.sb1000 b/Documentation/networking/device_drivers/sb1000.txt index f92c2aac56a9..f92c2aac56a9 100644 --- a/Documentation/networking/README.sb1000 +++ b/Documentation/networking/device_drivers/sb1000.txt diff --git a/Documentation/networking/smc9.txt b/Documentation/networking/device_drivers/smsc/smc9.txt index d1e15074e43d..d1e15074e43d 100644 --- a/Documentation/networking/smc9.txt +++ b/Documentation/networking/device_drivers/smsc/smc9.txt diff --git a/Documentation/networking/stmmac.txt b/Documentation/networking/device_drivers/stmicro/stmmac.txt index 2bb07078f535..2bb07078f535 100644 --- a/Documentation/networking/stmmac.txt +++ b/Documentation/networking/device_drivers/stmicro/stmmac.txt diff --git a/Documentation/networking/ti-cpsw.txt b/Documentation/networking/device_drivers/ti/cpsw.txt index d4d4c0751a09..d4d4c0751a09 100644 --- a/Documentation/networking/ti-cpsw.txt +++ b/Documentation/networking/device_drivers/ti/cpsw.txt diff --git a/Documentation/networking/tlan.txt b/Documentation/networking/device_drivers/ti/tlan.txt index 34550dfcef74..34550dfcef74 100644 --- a/Documentation/networking/tlan.txt +++ b/Documentation/networking/device_drivers/ti/tlan.txt diff --git a/Documentation/networking/spider_net.txt b/Documentation/networking/device_drivers/toshiba/spider_net.txt index b0b75f8463b3..b0b75f8463b3 100644 --- a/Documentation/networking/spider_net.txt +++ b/Documentation/networking/device_drivers/toshiba/spider_net.txt diff --git a/Documentation/networking/devlink-params.txt b/Documentation/networking/devlink-params.txt index ae444ffe73ac..2d26434ddcf8 100644 --- a/Documentation/networking/devlink-params.txt +++ b/Documentation/networking/devlink-params.txt @@ -40,3 +40,12 @@ msix_vec_per_pf_min [DEVICE, GENERIC] for the device initialization. Value is same across all physical functions (PFs) in the device. Type: u32 + +fw_load_policy [DEVICE, GENERIC] + Controls the device's firmware loading policy. + Valid values: + * DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_DRIVER (0) + Load firmware version preferred by the driver. + * DEVLINK_PARAM_FW_LOAD_POLICY_VALUE_FLASH (1) + Load firmware currently stored in flash. + Type: u8 diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst index bd89dae8d578..6a47629ef8ed 100644 --- a/Documentation/networking/index.rst +++ b/Documentation/networking/index.rst @@ -31,6 +31,7 @@ Contents: net_failover alias bridge + snmp_counter .. only:: subproject diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 32b21571adfe..acdfb5d2bcaa 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -108,8 +108,8 @@ neigh/default/gc_thresh2 - INTEGER Default: 512 neigh/default/gc_thresh3 - INTEGER - Maximum number of neighbor entries allowed. Increase this - when using large numbers of interfaces and when communicating + Maximum number of non-PERMANENT neighbor entries allowed. Increase + this when using large numbers of interfaces and when communicating with large numbers of directly-connected peers. Default: 1024 @@ -370,6 +370,7 @@ tcp_l3mdev_accept - BOOLEAN derived from the listen socket to be bound to the L3 domain in which the packets originated. Only valid when the kernel was compiled with CONFIG_NET_L3_MASTER_DEV. + Default: 0 (disabled) tcp_low_latency - BOOLEAN This is a legacy option, it has no effect anymore. @@ -758,7 +759,7 @@ tcp_limit_output_bytes - INTEGER flows, for typical pfifo_fast qdiscs. tcp_limit_output_bytes limits the number of bytes on qdisc or device to reduce artificial RTT/cwnd and reduce bufferbloat. - Default: 262144 + Default: 1048576 (16 * 65536) tcp_challenge_ack_limit - INTEGER Limits number of Challenge ACK sent per second, as recommended @@ -773,6 +774,7 @@ udp_l3mdev_accept - BOOLEAN being received regardless of the L3 domain in which they originated. Only valid when the kernel was compiled with CONFIG_NET_L3_MASTER_DEV. + Default: 0 (disabled) udp_mem - vector of 3 INTEGERs: min, pressure, max Number of pages allowed for queueing by all UDP sockets. @@ -799,6 +801,16 @@ udp_wmem_min - INTEGER total pages of UDP sockets exceed udp_mem pressure. The unit is byte. Default: 4K +RAW variables: + +raw_l3mdev_accept - BOOLEAN + Enabling this option allows a "global" bound socket to work + across L3 master domains (e.g., VRFs) with packets capable of + being received regardless of the L3 domain in which they + originated. Only valid when the kernel was compiled with + CONFIG_NET_L3_MASTER_DEV. + Default: 1 (enabled) + CIPSOv4 Variables: cipso_cache_enable - BOOLEAN diff --git a/Documentation/networking/netdev-features.txt b/Documentation/networking/netdev-features.txt index c4a54c162547..58dd1c1e3c65 100644 --- a/Documentation/networking/netdev-features.txt +++ b/Documentation/networking/netdev-features.txt @@ -115,7 +115,7 @@ set, be it TCPv4 (when NETIF_F_TSO is enabled) or TCPv6 (NETIF_F_TSO6). * Transmit UDP segmentation offload -NETIF_F_GSO_UDP_GSO_L4 accepts a single UDP header with a payload that exceeds +NETIF_F_GSO_UDP_L4 accepts a single UDP header with a payload that exceeds gso_size. On segmentation, it segments the payload on gso_size boundaries and replicates the network and UDP headers (fixing up the last one if less than gso_size). diff --git a/Documentation/networking/nf_conntrack-sysctl.txt b/Documentation/networking/nf_conntrack-sysctl.txt index 1669dc2419fd..f75c2ce6e136 100644 --- a/Documentation/networking/nf_conntrack-sysctl.txt +++ b/Documentation/networking/nf_conntrack-sysctl.txt @@ -157,7 +157,16 @@ nf_conntrack_udp_timeout - INTEGER (seconds) default 30 nf_conntrack_udp_timeout_stream - INTEGER (seconds) - default 180 + default 120 This extended timeout will be used in case there is an UDP stream detected. + +nf_conntrack_gre_timeout - INTEGER (seconds) + default 30 + +nf_conntrack_gre_timeout_stream - INTEGER (seconds) + default 180 + + This extended timeout will be used in case there is an GRE stream + detected. diff --git a/Documentation/networking/rxrpc.txt b/Documentation/networking/rxrpc.txt index 89f1302d593a..c9d052e0cf51 100644 --- a/Documentation/networking/rxrpc.txt +++ b/Documentation/networking/rxrpc.txt @@ -661,7 +661,7 @@ A server would be set up to accept operations in the following manner: setsockopt(server, SOL_RXRPC, RXRPC_SECURITY_KEYRING, "AFSkeys", 7); The keyring can be manipulated after it has been given to the socket. This - permits the server to add more keys, replace keys, etc. whilst it is live. + permits the server to add more keys, replace keys, etc. while it is live. (3) A local address must then be bound: @@ -1032,7 +1032,7 @@ The kernel interface functions are as follows: struct sockaddr_rxrpc *srx, struct key *key); - This attempts to partially reinitialise a call and submit it again whilst + This attempts to partially reinitialise a call and submit it again while reusing the original call's Tx queue to avoid the need to repackage and re-encrypt the data to be sent. call indicates the call to retry, srx the new address to send it to and key the encryption key to use for signing or @@ -1066,7 +1066,7 @@ The kernel interface functions are as follows: alive after waiting for a suitable interval. This allows the caller to work out if the server is still contactable and - if the call is still alive on the server whilst waiting for the server to + if the call is still alive on the server while waiting for the server to process a client operation. The second function causes a ping ACK to be transmitted to try to provoke @@ -1149,14 +1149,14 @@ adjusted through sysctls in /proc/net/rxrpc/: (*) connection_expiry The amount of time in seconds after a connection was last used before we - remove it from the connection list. Whilst a connection is in existence, + remove it from the connection list. While a connection is in existence, it serves as a placeholder for negotiated security; when it is deleted, the security must be renegotiated. (*) transport_expiry The amount of time in seconds after a transport was last used before we - remove it from the transport list. Whilst a transport is in existence, it + remove it from the transport list. While a transport is in existence, it serves to anchor the peer data and keeps the connection ID counter. (*) rxrpc_rx_window_size diff --git a/Documentation/networking/snmp_counter.rst b/Documentation/networking/snmp_counter.rst new file mode 100644 index 000000000000..b0dfdaaca512 --- /dev/null +++ b/Documentation/networking/snmp_counter.rst @@ -0,0 +1,1428 @@ +=========== +SNMP counter +=========== + +This document explains the meaning of SNMP counters. + +General IPv4 counters +==================== +All layer 4 packets and ICMP packets will change these counters, but +these counters won't be changed by layer 2 packets (such as STP) or +ARP packets. + +* IpInReceives +Defined in `RFC1213 ipInReceives`_ + +.. _RFC1213 ipInReceives: https://tools.ietf.org/html/rfc1213#page-26 + +The number of packets received by the IP layer. It gets increasing at the +beginning of ip_rcv function, always be updated together with +IpExtInOctets. It will be increased even if the packet is dropped +later (e.g. due to the IP header is invalid or the checksum is wrong +and so on). It indicates the number of aggregated segments after +GRO/LRO. + +* IpInDelivers +Defined in `RFC1213 ipInDelivers`_ + +.. _RFC1213 ipInDelivers: https://tools.ietf.org/html/rfc1213#page-28 + +The number of packets delivers to the upper layer protocols. E.g. TCP, UDP, +ICMP and so on. If no one listens on a raw socket, only kernel +supported protocols will be delivered, if someone listens on the raw +socket, all valid IP packets will be delivered. + +* IpOutRequests +Defined in `RFC1213 ipOutRequests`_ + +.. _RFC1213 ipOutRequests: https://tools.ietf.org/html/rfc1213#page-28 + +The number of packets sent via IP layer, for both single cast and +multicast packets, and would always be updated together with +IpExtOutOctets. + +* IpExtInOctets and IpExtOutOctets +They are Linux kernel extensions, no RFC definitions. Please note, +RFC1213 indeed defines ifInOctets and ifOutOctets, but they +are different things. The ifInOctets and ifOutOctets include the MAC +layer header size but IpExtInOctets and IpExtOutOctets don't, they +only include the IP layer header and the IP layer data. + +* IpExtInNoECTPkts, IpExtInECT1Pkts, IpExtInECT0Pkts, IpExtInCEPkts +They indicate the number of four kinds of ECN IP packets, please refer +`Explicit Congestion Notification`_ for more details. + +.. _Explicit Congestion Notification: https://tools.ietf.org/html/rfc3168#page-6 + +These 4 counters calculate how many packets received per ECN +status. They count the real frame number regardless the LRO/GRO. So +for the same packet, you might find that IpInReceives count 1, but +IpExtInNoECTPkts counts 2 or more. + +* IpInHdrErrors +Defined in `RFC1213 ipInHdrErrors`_. It indicates the packet is +dropped due to the IP header error. It might happen in both IP input +and IP forward paths. + +.. _RFC1213 ipInHdrErrors: https://tools.ietf.org/html/rfc1213#page-27 + +* IpInAddrErrors +Defined in `RFC1213 ipInAddrErrors`_. It will be increased in two +scenarios: (1) The IP address is invalid. (2) The destination IP +address is not a local address and IP forwarding is not enabled + +.. _RFC1213 ipInAddrErrors: https://tools.ietf.org/html/rfc1213#page-27 + +* IpExtInNoRoutes +This counter means the packet is dropped when the IP stack receives a +packet and can't find a route for it from the route table. It might +happen when IP forwarding is enabled and the destination IP address is +not a local address and there is no route for the destination IP +address. + +* IpInUnknownProtos +Defined in `RFC1213 ipInUnknownProtos`_. It will be increased if the +layer 4 protocol is unsupported by kernel. If an application is using +raw socket, kernel will always deliver the packet to the raw socket +and this counter won't be increased. + +.. _RFC1213 ipInUnknownProtos: https://tools.ietf.org/html/rfc1213#page-27 + +* IpExtInTruncatedPkts +For IPv4 packet, it means the actual data size is smaller than the +"Total Length" field in the IPv4 header. + +* IpInDiscards +Defined in `RFC1213 ipInDiscards`_. It indicates the packet is dropped +in the IP receiving path and due to kernel internal reasons (e.g. no +enough memory). + +.. _RFC1213 ipInDiscards: https://tools.ietf.org/html/rfc1213#page-28 + +* IpOutDiscards +Defined in `RFC1213 ipOutDiscards`_. It indicates the packet is +dropped in the IP sending path and due to kernel internal reasons. + +.. _RFC1213 ipOutDiscards: https://tools.ietf.org/html/rfc1213#page-28 + +* IpOutNoRoutes +Defined in `RFC1213 ipOutNoRoutes`_. It indicates the packet is +dropped in the IP sending path and no route is found for it. + +.. _RFC1213 ipOutNoRoutes: https://tools.ietf.org/html/rfc1213#page-29 + +ICMP counters +============ +* IcmpInMsgs and IcmpOutMsgs +Defined by `RFC1213 icmpInMsgs`_ and `RFC1213 icmpOutMsgs`_ + +.. _RFC1213 icmpInMsgs: https://tools.ietf.org/html/rfc1213#page-41 +.. _RFC1213 icmpOutMsgs: https://tools.ietf.org/html/rfc1213#page-43 + +As mentioned in the RFC1213, these two counters include errors, they +would be increased even if the ICMP packet has an invalid type. The +ICMP output path will check the header of a raw socket, so the +IcmpOutMsgs would still be updated if the IP header is constructed by +a userspace program. + +* ICMP named types +| These counters include most of common ICMP types, they are: +| IcmpInDestUnreachs: `RFC1213 icmpInDestUnreachs`_ +| IcmpInTimeExcds: `RFC1213 icmpInTimeExcds`_ +| IcmpInParmProbs: `RFC1213 icmpInParmProbs`_ +| IcmpInSrcQuenchs: `RFC1213 icmpInSrcQuenchs`_ +| IcmpInRedirects: `RFC1213 icmpInRedirects`_ +| IcmpInEchos: `RFC1213 icmpInEchos`_ +| IcmpInEchoReps: `RFC1213 icmpInEchoReps`_ +| IcmpInTimestamps: `RFC1213 icmpInTimestamps`_ +| IcmpInTimestampReps: `RFC1213 icmpInTimestampReps`_ +| IcmpInAddrMasks: `RFC1213 icmpInAddrMasks`_ +| IcmpInAddrMaskReps: `RFC1213 icmpInAddrMaskReps`_ +| IcmpOutDestUnreachs: `RFC1213 icmpOutDestUnreachs`_ +| IcmpOutTimeExcds: `RFC1213 icmpOutTimeExcds`_ +| IcmpOutParmProbs: `RFC1213 icmpOutParmProbs`_ +| IcmpOutSrcQuenchs: `RFC1213 icmpOutSrcQuenchs`_ +| IcmpOutRedirects: `RFC1213 icmpOutRedirects`_ +| IcmpOutEchos: `RFC1213 icmpOutEchos`_ +| IcmpOutEchoReps: `RFC1213 icmpOutEchoReps`_ +| IcmpOutTimestamps: `RFC1213 icmpOutTimestamps`_ +| IcmpOutTimestampReps: `RFC1213 icmpOutTimestampReps`_ +| IcmpOutAddrMasks: `RFC1213 icmpOutAddrMasks`_ +| IcmpOutAddrMaskReps: `RFC1213 icmpOutAddrMaskReps`_ + +.. _RFC1213 icmpInDestUnreachs: https://tools.ietf.org/html/rfc1213#page-41 +.. _RFC1213 icmpInTimeExcds: https://tools.ietf.org/html/rfc1213#page-41 +.. _RFC1213 icmpInParmProbs: https://tools.ietf.org/html/rfc1213#page-42 +.. _RFC1213 icmpInSrcQuenchs: https://tools.ietf.org/html/rfc1213#page-42 +.. _RFC1213 icmpInRedirects: https://tools.ietf.org/html/rfc1213#page-42 +.. _RFC1213 icmpInEchos: https://tools.ietf.org/html/rfc1213#page-42 +.. _RFC1213 icmpInEchoReps: https://tools.ietf.org/html/rfc1213#page-42 +.. _RFC1213 icmpInTimestamps: https://tools.ietf.org/html/rfc1213#page-42 +.. _RFC1213 icmpInTimestampReps: https://tools.ietf.org/html/rfc1213#page-43 +.. _RFC1213 icmpInAddrMasks: https://tools.ietf.org/html/rfc1213#page-43 +.. _RFC1213 icmpInAddrMaskReps: https://tools.ietf.org/html/rfc1213#page-43 + +.. _RFC1213 icmpOutDestUnreachs: https://tools.ietf.org/html/rfc1213#page-44 +.. _RFC1213 icmpOutTimeExcds: https://tools.ietf.org/html/rfc1213#page-44 +.. _RFC1213 icmpOutParmProbs: https://tools.ietf.org/html/rfc1213#page-44 +.. _RFC1213 icmpOutSrcQuenchs: https://tools.ietf.org/html/rfc1213#page-44 +.. _RFC1213 icmpOutRedirects: https://tools.ietf.org/html/rfc1213#page-44 +.. _RFC1213 icmpOutEchos: https://tools.ietf.org/html/rfc1213#page-45 +.. _RFC1213 icmpOutEchoReps: https://tools.ietf.org/html/rfc1213#page-45 +.. _RFC1213 icmpOutTimestamps: https://tools.ietf.org/html/rfc1213#page-45 +.. _RFC1213 icmpOutTimestampReps: https://tools.ietf.org/html/rfc1213#page-45 +.. _RFC1213 icmpOutAddrMasks: https://tools.ietf.org/html/rfc1213#page-45 +.. _RFC1213 icmpOutAddrMaskReps: https://tools.ietf.org/html/rfc1213#page-46 + +Every ICMP type has two counters: 'In' and 'Out'. E.g., for the ICMP +Echo packet, they are IcmpInEchos and IcmpOutEchos. Their meanings are +straightforward. The 'In' counter means kernel receives such a packet +and the 'Out' counter means kernel sends such a packet. + +* ICMP numeric types +They are IcmpMsgInType[N] and IcmpMsgOutType[N], the [N] indicates the +ICMP type number. These counters track all kinds of ICMP packets. The +ICMP type number definition could be found in the `ICMP parameters`_ +document. + +.. _ICMP parameters: https://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml + +For example, if the Linux kernel sends an ICMP Echo packet, the +IcmpMsgOutType8 would increase 1. And if kernel gets an ICMP Echo Reply +packet, IcmpMsgInType0 would increase 1. + +* IcmpInCsumErrors +This counter indicates the checksum of the ICMP packet is +wrong. Kernel verifies the checksum after updating the IcmpInMsgs and +before updating IcmpMsgInType[N]. If a packet has bad checksum, the +IcmpInMsgs would be updated but none of IcmpMsgInType[N] would be updated. + +* IcmpInErrors and IcmpOutErrors +Defined by `RFC1213 icmpInErrors`_ and `RFC1213 icmpOutErrors`_ + +.. _RFC1213 icmpInErrors: https://tools.ietf.org/html/rfc1213#page-41 +.. _RFC1213 icmpOutErrors: https://tools.ietf.org/html/rfc1213#page-43 + +When an error occurs in the ICMP packet handler path, these two +counters would be updated. The receiving packet path use IcmpInErrors +and the sending packet path use IcmpOutErrors. When IcmpInCsumErrors +is increased, IcmpInErrors would always be increased too. + +relationship of the ICMP counters +------------------------------- +The sum of IcmpMsgOutType[N] is always equal to IcmpOutMsgs, as they +are updated at the same time. The sum of IcmpMsgInType[N] plus +IcmpInErrors should be equal or larger than IcmpInMsgs. When kernel +receives an ICMP packet, kernel follows below logic: + +1. increase IcmpInMsgs +2. if has any error, update IcmpInErrors and finish the process +3. update IcmpMsgOutType[N] +4. handle the packet depending on the type, if has any error, update + IcmpInErrors and finish the process + +So if all errors occur in step (2), IcmpInMsgs should be equal to the +sum of IcmpMsgOutType[N] plus IcmpInErrors. If all errors occur in +step (4), IcmpInMsgs should be equal to the sum of +IcmpMsgOutType[N]. If the errors occur in both step (2) and step (4), +IcmpInMsgs should be less than the sum of IcmpMsgOutType[N] plus +IcmpInErrors. + +General TCP counters +================== +* TcpInSegs +Defined in `RFC1213 tcpInSegs`_ + +.. _RFC1213 tcpInSegs: https://tools.ietf.org/html/rfc1213#page-48 + +The number of packets received by the TCP layer. As mentioned in +RFC1213, it includes the packets received in error, such as checksum +error, invalid TCP header and so on. Only one error won't be included: +if the layer 2 destination address is not the NIC's layer 2 +address. It might happen if the packet is a multicast or broadcast +packet, or the NIC is in promiscuous mode. In these situations, the +packets would be delivered to the TCP layer, but the TCP layer will discard +these packets before increasing TcpInSegs. The TcpInSegs counter +isn't aware of GRO. So if two packets are merged by GRO, the TcpInSegs +counter would only increase 1. + +* TcpOutSegs +Defined in `RFC1213 tcpOutSegs`_ + +.. _RFC1213 tcpOutSegs: https://tools.ietf.org/html/rfc1213#page-48 + +The number of packets sent by the TCP layer. As mentioned in RFC1213, +it excludes the retransmitted packets. But it includes the SYN, ACK +and RST packets. Doesn't like TcpInSegs, the TcpOutSegs is aware of +GSO, so if a packet would be split to 2 by GSO, TcpOutSegs will +increase 2. + +* TcpActiveOpens +Defined in `RFC1213 tcpActiveOpens`_ + +.. _RFC1213 tcpActiveOpens: https://tools.ietf.org/html/rfc1213#page-47 + +It means the TCP layer sends a SYN, and come into the SYN-SENT +state. Every time TcpActiveOpens increases 1, TcpOutSegs should always +increase 1. + +* TcpPassiveOpens +Defined in `RFC1213 tcpPassiveOpens`_ + +.. _RFC1213 tcpPassiveOpens: https://tools.ietf.org/html/rfc1213#page-47 + +It means the TCP layer receives a SYN, replies a SYN+ACK, come into +the SYN-RCVD state. + +* TcpExtTCPRcvCoalesce +When packets are received by the TCP layer and are not be read by the +application, the TCP layer will try to merge them. This counter +indicate how many packets are merged in such situation. If GRO is +enabled, lots of packets would be merged by GRO, these packets +wouldn't be counted to TcpExtTCPRcvCoalesce. + +* TcpExtTCPAutoCorking +When sending packets, the TCP layer will try to merge small packets to +a bigger one. This counter increase 1 for every packet merged in such +situation. Please refer to the LWN article for more details: +https://lwn.net/Articles/576263/ + +* TcpExtTCPOrigDataSent +This counter is explained by `kernel commit f19c29e3e391`_, I pasted the +explaination below:: + + TCPOrigDataSent: number of outgoing packets with original data (excluding + retransmission but including data-in-SYN). This counter is different from + TcpOutSegs because TcpOutSegs also tracks pure ACKs. TCPOrigDataSent is + more useful to track the TCP retransmission rate. + +* TCPSynRetrans +This counter is explained by `kernel commit f19c29e3e391`_, I pasted the +explaination below:: + + TCPSynRetrans: number of SYN and SYN/ACK retransmits to break down + retransmissions into SYN, fast-retransmits, timeout retransmits, etc. + +* TCPFastOpenActiveFail +This counter is explained by `kernel commit f19c29e3e391`_, I pasted the +explaination below:: + + TCPFastOpenActiveFail: Fast Open attempts (SYN/data) failed because + the remote does not accept it or the attempts timed out. + +.. _kernel commit f19c29e3e391: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f19c29e3e391a66a273e9afebaf01917245148cd + +* TcpExtListenOverflows and TcpExtListenDrops +When kernel receives a SYN from a client, and if the TCP accept queue +is full, kernel will drop the SYN and add 1 to TcpExtListenOverflows. +At the same time kernel will also add 1 to TcpExtListenDrops. When a +TCP socket is in LISTEN state, and kernel need to drop a packet, +kernel would always add 1 to TcpExtListenDrops. So increase +TcpExtListenOverflows would let TcpExtListenDrops increasing at the +same time, but TcpExtListenDrops would also increase without +TcpExtListenOverflows increasing, e.g. a memory allocation fail would +also let TcpExtListenDrops increase. + +Note: The above explanation is based on kernel 4.10 or above version, on +an old kernel, the TCP stack has different behavior when TCP accept +queue is full. On the old kernel, TCP stack won't drop the SYN, it +would complete the 3-way handshake. As the accept queue is full, TCP +stack will keep the socket in the TCP half-open queue. As it is in the +half open queue, TCP stack will send SYN+ACK on an exponential backoff +timer, after client replies ACK, TCP stack checks whether the accept +queue is still full, if it is not full, moves the socket to the accept +queue, if it is full, keeps the socket in the half-open queue, at next +time client replies ACK, this socket will get another chance to move +to the accept queue. + + +TCP Fast Open +============ +When kernel receives a TCP packet, it has two paths to handler the +packet, one is fast path, another is slow path. The comment in kernel +code provides a good explanation of them, I pasted them below:: + + It is split into a fast path and a slow path. The fast path is + disabled when: + + - A zero window was announced from us + - zero window probing + is only handled properly on the slow path. + - Out of order segments arrived. + - Urgent data is expected. + - There is no buffer space left + - Unexpected TCP flags/window values/header lengths are received + (detected by checking the TCP header against pred_flags) + - Data is sent in both directions. The fast path only supports pure senders + or pure receivers (this means either the sequence number or the ack + value must stay constant) + - Unexpected TCP option. + +Kernel will try to use fast path unless any of the above conditions +are satisfied. If the packets are out of order, kernel will handle +them in slow path, which means the performance might be not very +good. Kernel would also come into slow path if the "Delayed ack" is +used, because when using "Delayed ack", the data is sent in both +directions. When the TCP window scale option is not used, kernel will +try to enable fast path immediately when the connection comes into the +established state, but if the TCP window scale option is used, kernel +will disable the fast path at first, and try to enable it after kernel +receives packets. + +* TcpExtTCPPureAcks and TcpExtTCPHPAcks +If a packet set ACK flag and has no data, it is a pure ACK packet, if +kernel handles it in the fast path, TcpExtTCPHPAcks will increase 1, +if kernel handles it in the slow path, TcpExtTCPPureAcks will +increase 1. + +* TcpExtTCPHPHits +If a TCP packet has data (which means it is not a pure ACK packet), +and this packet is handled in the fast path, TcpExtTCPHPHits will +increase 1. + + +TCP abort +======== + + +* TcpExtTCPAbortOnData +It means TCP layer has data in flight, but need to close the +connection. So TCP layer sends a RST to the other side, indicate the +connection is not closed very graceful. An easy way to increase this +counter is using the SO_LINGER option. Please refer to the SO_LINGER +section of the `socket man page`_: + +.. _socket man page: http://man7.org/linux/man-pages/man7/socket.7.html + +By default, when an application closes a connection, the close function +will return immediately and kernel will try to send the in-flight data +async. If you use the SO_LINGER option, set l_onoff to 1, and l_linger +to a positive number, the close function won't return immediately, but +wait for the in-flight data are acked by the other side, the max wait +time is l_linger seconds. If set l_onoff to 1 and set l_linger to 0, +when the application closes a connection, kernel will send a RST +immediately and increase the TcpExtTCPAbortOnData counter. + +* TcpExtTCPAbortOnClose +This counter means the application has unread data in the TCP layer when +the application wants to close the TCP connection. In such a situation, +kernel will send a RST to the other side of the TCP connection. + +* TcpExtTCPAbortOnMemory +When an application closes a TCP connection, kernel still need to track +the connection, let it complete the TCP disconnect process. E.g. an +app calls the close method of a socket, kernel sends fin to the other +side of the connection, then the app has no relationship with the +socket any more, but kernel need to keep the socket, this socket +becomes an orphan socket, kernel waits for the reply of the other side, +and would come to the TIME_WAIT state finally. When kernel has no +enough memory to keep the orphan socket, kernel would send an RST to +the other side, and delete the socket, in such situation, kernel will +increase 1 to the TcpExtTCPAbortOnMemory. Two conditions would trigger +TcpExtTCPAbortOnMemory: + +1. the memory used by the TCP protocol is higher than the third value of +the tcp_mem. Please refer the tcp_mem section in the `TCP man page`_: + +.. _TCP man page: http://man7.org/linux/man-pages/man7/tcp.7.html + +2. the orphan socket count is higher than net.ipv4.tcp_max_orphans + + +* TcpExtTCPAbortOnTimeout +This counter will increase when any of the TCP timers expire. In such +situation, kernel won't send RST, just give up the connection. + +* TcpExtTCPAbortOnLinger +When a TCP connection comes into FIN_WAIT_2 state, instead of waiting +for the fin packet from the other side, kernel could send a RST and +delete the socket immediately. This is not the default behavior of +Linux kernel TCP stack. By configuring the TCP_LINGER2 socket option, +you could let kernel follow this behavior. + +* TcpExtTCPAbortFailed +The kernel TCP layer will send RST if the `RFC2525 2.17 section`_ is +satisfied. If an internal error occurs during this process, +TcpExtTCPAbortFailed will be increased. + +.. _RFC2525 2.17 section: https://tools.ietf.org/html/rfc2525#page-50 + +TCP Hybrid Slow Start +==================== +The Hybrid Slow Start algorithm is an enhancement of the traditional +TCP congestion window Slow Start algorithm. It uses two pieces of +information to detect whether the max bandwidth of the TCP path is +approached. The two pieces of information are ACK train length and +increase in packet delay. For detail information, please refer the +`Hybrid Slow Start paper`_. Either ACK train length or packet delay +hits a specific threshold, the congestion control algorithm will come +into the Congestion Avoidance state. Until v4.20, two congestion +control algorithms are using Hybrid Slow Start, they are cubic (the +default congestion control algorithm) and cdg. Four snmp counters +relate with the Hybrid Slow Start algorithm. + +.. _Hybrid Slow Start paper: https://pdfs.semanticscholar.org/25e9/ef3f03315782c7f1cbcd31b587857adae7d1.pdf + +* TcpExtTCPHystartTrainDetect +How many times the ACK train length threshold is detected + +* TcpExtTCPHystartTrainCwnd +The sum of CWND detected by ACK train length. Dividing this value by +TcpExtTCPHystartTrainDetect is the average CWND which detected by the +ACK train length. + +* TcpExtTCPHystartDelayDetect +How many times the packet delay threshold is detected. + +* TcpExtTCPHystartDelayCwnd +The sum of CWND detected by packet delay. Dividing this value by +TcpExtTCPHystartDelayDetect is the average CWND which detected by the +packet delay. + +TCP retransmission and congestion control +====================================== +The TCP protocol has two retransmission mechanisms: SACK and fast +recovery. They are exclusive with each other. When SACK is enabled, +the kernel TCP stack would use SACK, or kernel would use fast +recovery. The SACK is a TCP option, which is defined in `RFC2018`_, +the fast recovery is defined in `RFC6582`_, which is also called +'Reno'. + +The TCP congestion control is a big and complex topic. To understand +the related snmp counter, we need to know the states of the congestion +control state machine. There are 5 states: Open, Disorder, CWR, +Recovery and Loss. For details about these states, please refer page 5 +and page 6 of this document: +https://pdfs.semanticscholar.org/0e9c/968d09ab2e53e24c4dca5b2d67c7f7140f8e.pdf + +.. _RFC2018: https://tools.ietf.org/html/rfc2018 +.. _RFC6582: https://tools.ietf.org/html/rfc6582 + +* TcpExtTCPRenoRecovery and TcpExtTCPSackRecovery +When the congestion control comes into Recovery state, if sack is +used, TcpExtTCPSackRecovery increases 1, if sack is not used, +TcpExtTCPRenoRecovery increases 1. These two counters mean the TCP +stack begins to retransmit the lost packets. + +* TcpExtTCPSACKReneging +A packet was acknowledged by SACK, but the receiver has dropped this +packet, so the sender needs to retransmit this packet. In this +situation, the sender adds 1 to TcpExtTCPSACKReneging. A receiver +could drop a packet which has been acknowledged by SACK, although it is +unusual, it is allowed by the TCP protocol. The sender doesn't really +know what happened on the receiver side. The sender just waits until +the RTO expires for this packet, then the sender assumes this packet +has been dropped by the receiver. + +* TcpExtTCPRenoReorder +The reorder packet is detected by fast recovery. It would only be used +if SACK is disabled. The fast recovery algorithm detects recorder by +the duplicate ACK number. E.g., if retransmission is triggered, and +the original retransmitted packet is not lost, it is just out of +order, the receiver would acknowledge multiple times, one for the +retransmitted packet, another for the arriving of the original out of +order packet. Thus the sender would find more ACks than its +expectation, and the sender knows out of order occurs. + +* TcpExtTCPTSReorder +The reorder packet is detected when a hole is filled. E.g., assume the +sender sends packet 1,2,3,4,5, and the receiving order is +1,2,4,5,3. When the sender receives the ACK of packet 3 (which will +fill the hole), two conditions will let TcpExtTCPTSReorder increase +1: (1) if the packet 3 is not re-retransmitted yet. (2) if the packet +3 is retransmitted but the timestamp of the packet 3's ACK is earlier +than the retransmission timestamp. + +* TcpExtTCPSACKReorder +The reorder packet detected by SACK. The SACK has two methods to +detect reorder: (1) DSACK is received by the sender. It means the +sender sends the same packet more than one times. And the only reason +is the sender believes an out of order packet is lost so it sends the +packet again. (2) Assume packet 1,2,3,4,5 are sent by the sender, and +the sender has received SACKs for packet 2 and 5, now the sender +receives SACK for packet 4 and the sender doesn't retransmit the +packet yet, the sender would know packet 4 is out of order. The TCP +stack of kernel will increase TcpExtTCPSACKReorder for both of the +above scenarios. + + +DSACK +===== +The DSACK is defined in `RFC2883`_. The receiver uses DSACK to report +duplicate packets to the sender. There are two kinds of +duplications: (1) a packet which has been acknowledged is +duplicate. (2) an out of order packet is duplicate. The TCP stack +counts these two kinds of duplications on both receiver side and +sender side. + +.. _RFC2883 : https://tools.ietf.org/html/rfc2883 + +* TcpExtTCPDSACKOldSent +The TCP stack receives a duplicate packet which has been acked, so it +sends a DSACK to the sender. + +* TcpExtTCPDSACKOfoSent +The TCP stack receives an out of order duplicate packet, so it sends a +DSACK to the sender. + +* TcpExtTCPDSACKRecv +The TCP stack receives a DSACK, which indicate an acknowledged +duplicate packet is received. + +* TcpExtTCPDSACKOfoRecv +The TCP stack receives a DSACK, which indicate an out of order +duplicate packet is received. + +TCP out of order +=============== +* TcpExtTCPOFOQueue +The TCP layer receives an out of order packet and has enough memory +to queue it. + +* TcpExtTCPOFODrop +The TCP layer receives an out of order packet but doesn't have enough +memory, so drops it. Such packets won't be counted into +TcpExtTCPOFOQueue. + +* TcpExtTCPOFOMerge +The received out of order packet has an overlay with the previous +packet. the overlay part will be dropped. All of TcpExtTCPOFOMerge +packets will also be counted into TcpExtTCPOFOQueue. + +TCP PAWS +======= +PAWS (Protection Against Wrapped Sequence numbers) is an algorithm +which is used to drop old packets. It depends on the TCP +timestamps. For detail information, please refer the `timestamp wiki`_ +and the `RFC of PAWS`_. + +.. _RFC of PAWS: https://tools.ietf.org/html/rfc1323#page-17 +.. _timestamp wiki: https://en.wikipedia.org/wiki/Transmission_Control_Protocol#TCP_timestamps + +* TcpExtPAWSActive +Packets are dropped by PAWS in Syn-Sent status. + +* TcpExtPAWSEstab +Packets are dropped by PAWS in any status other than Syn-Sent. + +TCP ACK skip +=========== +In some scenarios, kernel would avoid sending duplicate ACKs too +frequently. Please find more details in the tcp_invalid_ratelimit +section of the `sysctl document`_. When kernel decides to skip an ACK +due to tcp_invalid_ratelimit, kernel would update one of below +counters to indicate the ACK is skipped in which scenario. The ACK +would only be skipped if the received packet is either a SYN packet or +it has no data. + +.. _sysctl document: https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt + +* TcpExtTCPACKSkippedSynRecv +The ACK is skipped in Syn-Recv status. The Syn-Recv status means the +TCP stack receives a SYN and replies SYN+ACK. Now the TCP stack is +waiting for an ACK. Generally, the TCP stack doesn't need to send ACK +in the Syn-Recv status. But in several scenarios, the TCP stack need +to send an ACK. E.g., the TCP stack receives the same SYN packet +repeately, the received packet does not pass the PAWS check, or the +received packet sequence number is out of window. In these scenarios, +the TCP stack needs to send ACK. If the ACk sending frequency is higher than +tcp_invalid_ratelimit allows, the TCP stack will skip sending ACK and +increase TcpExtTCPACKSkippedSynRecv. + + +* TcpExtTCPACKSkippedPAWS +The ACK is skipped due to PAWS (Protect Against Wrapped Sequence +numbers) check fails. If the PAWS check fails in Syn-Recv, Fin-Wait-2 +or Time-Wait statuses, the skipped ACK would be counted to +TcpExtTCPACKSkippedSynRecv, TcpExtTCPACKSkippedFinWait2 or +TcpExtTCPACKSkippedTimeWait. In all other statuses, the skipped ACK +would be counted to TcpExtTCPACKSkippedPAWS. + +* TcpExtTCPACKSkippedSeq +The sequence number is out of window and the timestamp passes the PAWS +check and the TCP status is not Syn-Recv, Fin-Wait-2, and Time-Wait. + +* TcpExtTCPACKSkippedFinWait2 +The ACK is skipped in Fin-Wait-2 status, the reason would be either +PAWS check fails or the received sequence number is out of window. + +* TcpExtTCPACKSkippedTimeWait +Tha ACK is skipped in Time-Wait status, the reason would be either +PAWS check failed or the received sequence number is out of window. + +* TcpExtTCPACKSkippedChallenge +The ACK is skipped if the ACK is a challenge ACK. The RFC 5961 defines +3 kind of challenge ACK, please refer `RFC 5961 section 3.2`_, +`RFC 5961 section 4.2`_ and `RFC 5961 section 5.2`_. Besides these +three scenarios, In some TCP status, the linux TCP stack would also +send challenge ACKs if the ACK number is before the first +unacknowledged number (more strict than `RFC 5961 section 5.2`_). + +.. _RFC 5961 section 3.2: https://tools.ietf.org/html/rfc5961#page-7 +.. _RFC 5961 section 4.2: https://tools.ietf.org/html/rfc5961#page-9 +.. _RFC 5961 section 5.2: https://tools.ietf.org/html/rfc5961#page-11 + + +examples +======= + +ping test +-------- +Run the ping command against the public dns server 8.8.8.8:: + + nstatuser@nstat-a:~$ ping 8.8.8.8 -c 1 + PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. + 64 bytes from 8.8.8.8: icmp_seq=1 ttl=119 time=17.8 ms + + --- 8.8.8.8 ping statistics --- + 1 packets transmitted, 1 received, 0% packet loss, time 0ms + rtt min/avg/max/mdev = 17.875/17.875/17.875/0.000 ms + +The nstayt result:: + + nstatuser@nstat-a:~$ nstat + #kernel + IpInReceives 1 0.0 + IpInDelivers 1 0.0 + IpOutRequests 1 0.0 + IcmpInMsgs 1 0.0 + IcmpInEchoReps 1 0.0 + IcmpOutMsgs 1 0.0 + IcmpOutEchos 1 0.0 + IcmpMsgInType0 1 0.0 + IcmpMsgOutType8 1 0.0 + IpExtInOctets 84 0.0 + IpExtOutOctets 84 0.0 + IpExtInNoECTPkts 1 0.0 + +The Linux server sent an ICMP Echo packet, so IpOutRequests, +IcmpOutMsgs, IcmpOutEchos and IcmpMsgOutType8 were increased 1. The +server got ICMP Echo Reply from 8.8.8.8, so IpInReceives, IcmpInMsgs, +IcmpInEchoReps and IcmpMsgInType0 were increased 1. The ICMP Echo Reply +was passed to the ICMP layer via IP layer, so IpInDelivers was +increased 1. The default ping data size is 48, so an ICMP Echo packet +and its corresponding Echo Reply packet are constructed by: + +* 14 bytes MAC header +* 20 bytes IP header +* 16 bytes ICMP header +* 48 bytes data (default value of the ping command) + +So the IpExtInOctets and IpExtOutOctets are 20+16+48=84. + +tcp 3-way handshake +------------------ +On server side, we run:: + + nstatuser@nstat-b:~$ nc -lknv 0.0.0.0 9000 + Listening on [0.0.0.0] (family 0, port 9000) + +On client side, we run:: + + nstatuser@nstat-a:~$ nc -nv 192.168.122.251 9000 + Connection to 192.168.122.251 9000 port [tcp/*] succeeded! + +The server listened on tcp 9000 port, the client connected to it, they +completed the 3-way handshake. + +On server side, we can find below nstat output:: + + nstatuser@nstat-b:~$ nstat | grep -i tcp + TcpPassiveOpens 1 0.0 + TcpInSegs 2 0.0 + TcpOutSegs 1 0.0 + TcpExtTCPPureAcks 1 0.0 + +On client side, we can find below nstat output:: + + nstatuser@nstat-a:~$ nstat | grep -i tcp + TcpActiveOpens 1 0.0 + TcpInSegs 1 0.0 + TcpOutSegs 2 0.0 + +When the server received the first SYN, it replied a SYN+ACK, and came into +SYN-RCVD state, so TcpPassiveOpens increased 1. The server received +SYN, sent SYN+ACK, received ACK, so server sent 1 packet, received 2 +packets, TcpInSegs increased 2, TcpOutSegs increased 1. The last ACK +of the 3-way handshake is a pure ACK without data, so +TcpExtTCPPureAcks increased 1. + +When the client sent SYN, the client came into the SYN-SENT state, so +TcpActiveOpens increased 1, the client sent SYN, received SYN+ACK, sent +ACK, so client sent 2 packets, received 1 packet, TcpInSegs increased +1, TcpOutSegs increased 2. + +TCP normal traffic +----------------- +Run nc on server:: + + nstatuser@nstat-b:~$ nc -lkv 0.0.0.0 9000 + Listening on [0.0.0.0] (family 0, port 9000) + +Run nc on client:: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + Connection to nstat-b 9000 port [tcp/*] succeeded! + +Input a string in the nc client ('hello' in our example):: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + Connection to nstat-b 9000 port [tcp/*] succeeded! + hello + +The client side nstat output:: + + nstatuser@nstat-a:~$ nstat + #kernel + IpInReceives 1 0.0 + IpInDelivers 1 0.0 + IpOutRequests 1 0.0 + TcpInSegs 1 0.0 + TcpOutSegs 1 0.0 + TcpExtTCPPureAcks 1 0.0 + TcpExtTCPOrigDataSent 1 0.0 + IpExtInOctets 52 0.0 + IpExtOutOctets 58 0.0 + IpExtInNoECTPkts 1 0.0 + +The server side nstat output:: + + nstatuser@nstat-b:~$ nstat + #kernel + IpInReceives 1 0.0 + IpInDelivers 1 0.0 + IpOutRequests 1 0.0 + TcpInSegs 1 0.0 + TcpOutSegs 1 0.0 + IpExtInOctets 58 0.0 + IpExtOutOctets 52 0.0 + IpExtInNoECTPkts 1 0.0 + +Input a string in nc client side again ('world' in our exmaple):: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + Connection to nstat-b 9000 port [tcp/*] succeeded! + hello + world + +Client side nstat output:: + + nstatuser@nstat-a:~$ nstat + #kernel + IpInReceives 1 0.0 + IpInDelivers 1 0.0 + IpOutRequests 1 0.0 + TcpInSegs 1 0.0 + TcpOutSegs 1 0.0 + TcpExtTCPHPAcks 1 0.0 + TcpExtTCPOrigDataSent 1 0.0 + IpExtInOctets 52 0.0 + IpExtOutOctets 58 0.0 + IpExtInNoECTPkts 1 0.0 + + +Server side nstat output:: + + nstatuser@nstat-b:~$ nstat + #kernel + IpInReceives 1 0.0 + IpInDelivers 1 0.0 + IpOutRequests 1 0.0 + TcpInSegs 1 0.0 + TcpOutSegs 1 0.0 + TcpExtTCPHPHits 1 0.0 + IpExtInOctets 58 0.0 + IpExtOutOctets 52 0.0 + IpExtInNoECTPkts 1 0.0 + +Compare the first client-side nstat and the second client-side nstat, +we could find one difference: the first one had a 'TcpExtTCPPureAcks', +but the second one had a 'TcpExtTCPHPAcks'. The first server-side +nstat and the second server-side nstat had a difference too: the +second server-side nstat had a TcpExtTCPHPHits, but the first +server-side nstat didn't have it. The network traffic patterns were +exactly the same: the client sent a packet to the server, the server +replied an ACK. But kernel handled them in different ways. When the +TCP window scale option is not used, kernel will try to enable fast +path immediately when the connection comes into the established state, +but if the TCP window scale option is used, kernel will disable the +fast path at first, and try to enable it after kerenl receives +packets. We could use the 'ss' command to verify whether the window +scale option is used. e.g. run below command on either server or +client:: + + nstatuser@nstat-a:~$ ss -o state established -i '( dport = :9000 or sport = :9000 ) + Netid Recv-Q Send-Q Local Address:Port Peer Address:Port + tcp 0 0 192.168.122.250:40654 192.168.122.251:9000 + ts sack cubic wscale:7,7 rto:204 rtt:0.98/0.49 mss:1448 pmtu:1500 rcvmss:536 advmss:1448 cwnd:10 bytes_acked:1 segs_out:2 segs_in:1 send 118.2Mbps lastsnd:46572 lastrcv:46572 lastack:46572 pacing_rate 236.4Mbps rcv_space:29200 rcv_ssthresh:29200 minrtt:0.98 + +The 'wscale:7,7' means both server and client set the window scale +option to 7. Now we could explain the nstat output in our test: + +In the first nstat output of client side, the client sent a packet, server +reply an ACK, when kernel handled this ACK, the fast path was not +enabled, so the ACK was counted into 'TcpExtTCPPureAcks'. + +In the second nstat output of client side, the client sent a packet again, +and received another ACK from the server, in this time, the fast path is +enabled, and the ACK was qualified for fast path, so it was handled by +the fast path, so this ACK was counted into TcpExtTCPHPAcks. + +In the first nstat output of server side, fast path was not enabled, +so there was no 'TcpExtTCPHPHits'. + +In the second nstat output of server side, the fast path was enabled, +and the packet received from client qualified for fast path, so it +was counted into 'TcpExtTCPHPHits'. + +TcpExtTCPAbortOnClose +-------------------- +On the server side, we run below python script:: + + import socket + import time + + port = 9000 + + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.bind(('0.0.0.0', port)) + s.listen(1) + sock, addr = s.accept() + while True: + time.sleep(9999999) + +This python script listen on 9000 port, but doesn't read anything from +the connection. + +On the client side, we send the string "hello" by nc:: + + nstatuser@nstat-a:~$ echo "hello" | nc nstat-b 9000 + +Then, we come back to the server side, the server has received the "hello" +packet, and the TCP layer has acked this packet, but the application didn't +read it yet. We type Ctrl-C to terminate the server script. Then we +could find TcpExtTCPAbortOnClose increased 1 on the server side:: + + nstatuser@nstat-b:~$ nstat | grep -i abort + TcpExtTCPAbortOnClose 1 0.0 + +If we run tcpdump on the server side, we could find the server sent a +RST after we type Ctrl-C. + +TcpExtTCPAbortOnMemory and TcpExtTCPAbortOnTimeout +----------------------------------------------- +Below is an example which let the orphan socket count be higher than +net.ipv4.tcp_max_orphans. +Change tcp_max_orphans to a smaller value on client:: + + sudo bash -c "echo 10 > /proc/sys/net/ipv4/tcp_max_orphans" + +Client code (create 64 connection to server):: + + nstatuser@nstat-a:~$ cat client_orphan.py + import socket + import time + + server = 'nstat-b' # server address + port = 9000 + + count = 64 + + connection_list = [] + + for i in range(64): + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.connect((server, port)) + connection_list.append(s) + print("connection_count: %d" % len(connection_list)) + + while True: + time.sleep(99999) + +Server code (accept 64 connection from client):: + + nstatuser@nstat-b:~$ cat server_orphan.py + import socket + import time + + port = 9000 + count = 64 + + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.bind(('0.0.0.0', port)) + s.listen(count) + connection_list = [] + while True: + sock, addr = s.accept() + connection_list.append((sock, addr)) + print("connection_count: %d" % len(connection_list)) + +Run the python scripts on server and client. + +On server:: + + python3 server_orphan.py + +On client:: + + python3 client_orphan.py + +Run iptables on server:: + + sudo iptables -A INPUT -i ens3 -p tcp --destination-port 9000 -j DROP + +Type Ctrl-C on client, stop client_orphan.py. + +Check TcpExtTCPAbortOnMemory on client:: + + nstatuser@nstat-a:~$ nstat | grep -i abort + TcpExtTCPAbortOnMemory 54 0.0 + +Check orphane socket count on client:: + + nstatuser@nstat-a:~$ ss -s + Total: 131 (kernel 0) + TCP: 14 (estab 1, closed 0, orphaned 10, synrecv 0, timewait 0/0), ports 0 + + Transport Total IP IPv6 + * 0 - - + RAW 1 0 1 + UDP 1 1 0 + TCP 14 13 1 + INET 16 14 2 + FRAG 0 0 0 + +The explanation of the test: after run server_orphan.py and +client_orphan.py, we set up 64 connections between server and +client. Run the iptables command, the server will drop all packets from +the client, type Ctrl-C on client_orphan.py, the system of the client +would try to close these connections, and before they are closed +gracefully, these connections became orphan sockets. As the iptables +of the server blocked packets from the client, the server won't receive fin +from the client, so all connection on clients would be stuck on FIN_WAIT_1 +stage, so they will keep as orphan sockets until timeout. We have echo +10 to /proc/sys/net/ipv4/tcp_max_orphans, so the client system would +only keep 10 orphan sockets, for all other orphan sockets, the client +system sent RST for them and delete them. We have 64 connections, so +the 'ss -s' command shows the system has 10 orphan sockets, and the +value of TcpExtTCPAbortOnMemory was 54. + +An additional explanation about orphan socket count: You could find the +exactly orphan socket count by the 'ss -s' command, but when kernel +decide whither increases TcpExtTCPAbortOnMemory and sends RST, kernel +doesn't always check the exactly orphan socket count. For increasing +performance, kernel checks an approximate count firstly, if the +approximate count is more than tcp_max_orphans, kernel checks the +exact count again. So if the approximate count is less than +tcp_max_orphans, but exactly count is more than tcp_max_orphans, you +would find TcpExtTCPAbortOnMemory is not increased at all. If +tcp_max_orphans is large enough, it won't occur, but if you decrease +tcp_max_orphans to a small value like our test, you might find this +issue. So in our test, the client set up 64 connections although the +tcp_max_orphans is 10. If the client only set up 11 connections, we +can't find the change of TcpExtTCPAbortOnMemory. + +Continue the previous test, we wait for several minutes. Because of the +iptables on the server blocked the traffic, the server wouldn't receive +fin, and all the client's orphan sockets would timeout on the +FIN_WAIT_1 state finally. So we wait for a few minutes, we could find +10 timeout on the client:: + + nstatuser@nstat-a:~$ nstat | grep -i abort + TcpExtTCPAbortOnTimeout 10 0.0 + +TcpExtTCPAbortOnLinger +--------------------- +The server side code:: + + nstatuser@nstat-b:~$ cat server_linger.py + import socket + import time + + port = 9000 + + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.bind(('0.0.0.0', port)) + s.listen(1) + sock, addr = s.accept() + while True: + time.sleep(9999999) + +The client side code:: + + nstatuser@nstat-a:~$ cat client_linger.py + import socket + import struct + + server = 'nstat-b' # server address + port = 9000 + + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.setsockopt(socket.SOL_SOCKET, socket.SO_LINGER, struct.pack('ii', 1, 10)) + s.setsockopt(socket.SOL_TCP, socket.TCP_LINGER2, struct.pack('i', -1)) + s.connect((server, port)) + s.close() + +Run server_linger.py on server:: + + nstatuser@nstat-b:~$ python3 server_linger.py + +Run client_linger.py on client:: + + nstatuser@nstat-a:~$ python3 client_linger.py + +After run client_linger.py, check the output of nstat:: + + nstatuser@nstat-a:~$ nstat | grep -i abort + TcpExtTCPAbortOnLinger 1 0.0 + +TcpExtTCPRcvCoalesce +------------------- +On the server, we run a program which listen on TCP port 9000, but +doesn't read any data:: + + import socket + import time + port = 9000 + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.bind(('0.0.0.0', port)) + s.listen(1) + sock, addr = s.accept() + while True: + time.sleep(9999999) + +Save the above code as server_coalesce.py, and run:: + + python3 server_coalesce.py + +On the client, save below code as client_coalesce.py:: + + import socket + server = 'nstat-b' + port = 9000 + s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + s.connect((server, port)) + +Run:: + + nstatuser@nstat-a:~$ python3 -i client_coalesce.py + +We use '-i' to come into the interactive mode, then a packet:: + + >>> s.send(b'foo') + 3 + +Send a packet again:: + + >>> s.send(b'bar') + 3 + +On the server, run nstat:: + + ubuntu@nstat-b:~$ nstat + #kernel + IpInReceives 2 0.0 + IpInDelivers 2 0.0 + IpOutRequests 2 0.0 + TcpInSegs 2 0.0 + TcpOutSegs 2 0.0 + TcpExtTCPRcvCoalesce 1 0.0 + IpExtInOctets 110 0.0 + IpExtOutOctets 104 0.0 + IpExtInNoECTPkts 2 0.0 + +The client sent two packets, server didn't read any data. When +the second packet arrived at server, the first packet was still in +the receiving queue. So the TCP layer merged the two packets, and we +could find the TcpExtTCPRcvCoalesce increased 1. + +TcpExtListenOverflows and TcpExtListenDrops +---------------------------------------- +On server, run the nc command, listen on port 9000:: + + nstatuser@nstat-b:~$ nc -lkv 0.0.0.0 9000 + Listening on [0.0.0.0] (family 0, port 9000) + +On client, run 3 nc commands in different terminals:: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + Connection to nstat-b 9000 port [tcp/*] succeeded! + +The nc command only accepts 1 connection, and the accept queue length +is 1. On current linux implementation, set queue length to n means the +actual queue length is n+1. Now we create 3 connections, 1 is accepted +by nc, 2 in accepted queue, so the accept queue is full. + +Before running the 4th nc, we clean the nstat history on the server:: + + nstatuser@nstat-b:~$ nstat -n + +Run the 4th nc on the client:: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + +If the nc server is running on kernel 4.10 or higher version, you +won't see the "Connection to ... succeeded!" string, because kernel +will drop the SYN if the accept queue is full. If the nc client is running +on an old kernel, you would see that the connection is succeeded, +because kernel would complete the 3 way handshake and keep the socket +on half open queue. I did the test on kernel 4.15. Below is the nstat +on the server:: + + nstatuser@nstat-b:~$ nstat + #kernel + IpInReceives 4 0.0 + IpInDelivers 4 0.0 + TcpInSegs 4 0.0 + TcpExtListenOverflows 4 0.0 + TcpExtListenDrops 4 0.0 + IpExtInOctets 240 0.0 + IpExtInNoECTPkts 4 0.0 + +Both TcpExtListenOverflows and TcpExtListenDrops were 4. If the time +between the 4th nc and the nstat was longer, the value of +TcpExtListenOverflows and TcpExtListenDrops would be larger, because +the SYN of the 4th nc was dropped, the client was retrying. + +IpInAddrErrors, IpExtInNoRoutes and IpOutNoRoutes +---------------------------------------------- +server A IP address: 192.168.122.250 +server B IP address: 192.168.122.251 +Prepare on server A, add a route to server B:: + + $ sudo ip route add 8.8.8.8/32 via 192.168.122.251 + +Prepare on server B, disable send_redirects for all interfaces:: + + $ sudo sysctl -w net.ipv4.conf.all.send_redirects=0 + $ sudo sysctl -w net.ipv4.conf.ens3.send_redirects=0 + $ sudo sysctl -w net.ipv4.conf.lo.send_redirects=0 + $ sudo sysctl -w net.ipv4.conf.default.send_redirects=0 + +We want to let sever A send a packet to 8.8.8.8, and route the packet +to server B. When server B receives such packet, it might send a ICMP +Redirect message to server A, set send_redirects to 0 will disable +this behavior. + +First, generate InAddrErrors. On server B, we disable IP forwarding:: + + $ sudo sysctl -w net.ipv4.conf.all.forwarding=0 + +On server A, we send packets to 8.8.8.8:: + + $ nc -v 8.8.8.8 53 + +On server B, we check the output of nstat:: + + $ nstat + #kernel + IpInReceives 3 0.0 + IpInAddrErrors 3 0.0 + IpExtInOctets 180 0.0 + IpExtInNoECTPkts 3 0.0 + +As we have let server A route 8.8.8.8 to server B, and we disabled IP +forwarding on server B, Server A sent packets to server B, then server B +dropped packets and increased IpInAddrErrors. As the nc command would +re-send the SYN packet if it didn't receive a SYN+ACK, we could find +multiple IpInAddrErrors. + +Second, generate IpExtInNoRoutes. On server B, we enable IP +forwarding:: + + $ sudo sysctl -w net.ipv4.conf.all.forwarding=1 + +Check the route table of server B and remove the default route:: + + $ ip route show + default via 192.168.122.1 dev ens3 proto static + 192.168.122.0/24 dev ens3 proto kernel scope link src 192.168.122.251 + $ sudo ip route delete default via 192.168.122.1 dev ens3 proto static + +On server A, we contact 8.8.8.8 again:: + + $ nc -v 8.8.8.8 53 + nc: connect to 8.8.8.8 port 53 (tcp) failed: Network is unreachable + +On server B, run nstat:: + + $ nstat + #kernel + IpInReceives 1 0.0 + IpOutRequests 1 0.0 + IcmpOutMsgs 1 0.0 + IcmpOutDestUnreachs 1 0.0 + IcmpMsgOutType3 1 0.0 + IpExtInNoRoutes 1 0.0 + IpExtInOctets 60 0.0 + IpExtOutOctets 88 0.0 + IpExtInNoECTPkts 1 0.0 + +We enabled IP forwarding on server B, when server B received a packet +which destination IP address is 8.8.8.8, server B will try to forward +this packet. We have deleted the default route, there was no route for +8.8.8.8, so server B increase IpExtInNoRoutes and sent the "ICMP +Destination Unreachable" message to server A. + +Third, generate IpOutNoRoutes. Run ping command on server B:: + + $ ping -c 1 8.8.8.8 + connect: Network is unreachable + +Run nstat on server B:: + + $ nstat + #kernel + IpOutNoRoutes 1 0.0 + +We have deleted the default route on server B. Server B couldn't find +a route for the 8.8.8.8 IP address, so server B increased +IpOutNoRoutes. + +TcpExtTCPACKSkippedSynRecv +------------------------ +In this test, we send 3 same SYN packets from client to server. The +first SYN will let server create a socket, set it to Syn-Recv status, +and reply a SYN/ACK. The second SYN will let server reply the SYN/ACK +again, and record the reply time (the duplicate ACK reply time). The +third SYN will let server check the previous duplicate ACK reply time, +and decide to skip the duplicate ACK, then increase the +TcpExtTCPACKSkippedSynRecv counter. + +Run tcpdump to capture a SYN packet:: + + nstatuser@nstat-a:~$ sudo tcpdump -c 1 -w /tmp/syn.pcap port 9000 + tcpdump: listening on ens3, link-type EN10MB (Ethernet), capture size 262144 bytes + +Open another terminal, run nc command:: + + nstatuser@nstat-a:~$ nc nstat-b 9000 + +As the nstat-b didn't listen on port 9000, it should reply a RST, and +the nc command exited immediately. It was enough for the tcpdump +command to capture a SYN packet. A linux server might use hardware +offload for the TCP checksum, so the checksum in the /tmp/syn.pcap +might be not correct. We call tcprewrite to fix it:: + + nstatuser@nstat-a:~$ tcprewrite --infile=/tmp/syn.pcap --outfile=/tmp/syn_fixcsum.pcap --fixcsum + +On nstat-b, we run nc to listen on port 9000:: + + nstatuser@nstat-b:~$ nc -lkv 9000 + Listening on [0.0.0.0] (family 0, port 9000) + +On nstat-a, we blocked the packet from port 9000, or nstat-a would send +RST to nstat-b:: + + nstatuser@nstat-a:~$ sudo iptables -A INPUT -p tcp --sport 9000 -j DROP + +Send 3 SYN repeatly to nstat-b:: + + nstatuser@nstat-a:~$ for i in {1..3}; do sudo tcpreplay -i ens3 /tmp/syn_fixcsum.pcap; done + +Check snmp cunter on nstat-b:: + + nstatuser@nstat-b:~$ nstat | grep -i skip + TcpExtTCPACKSkippedSynRecv 1 0.0 + +As we expected, TcpExtTCPACKSkippedSynRecv is 1. + +TcpExtTCPACKSkippedPAWS +---------------------- +To trigger PAWS, we could send an old SYN. + +On nstat-b, let nc listen on port 9000:: + + nstatuser@nstat-b:~$ nc -lkv 9000 + Listening on [0.0.0.0] (family 0, port 9000) + +On nstat-a, run tcpdump to capture a SYN:: + + nstatuser@nstat-a:~$ sudo tcpdump -w /tmp/paws_pre.pcap -c 1 port 9000 + tcpdump: listening on ens3, link-type EN10MB (Ethernet), capture size 262144 bytes + +On nstat-a, run nc as a client to connect nstat-b:: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + Connection to nstat-b 9000 port [tcp/*] succeeded! + +Now the tcpdump has captured the SYN and exit. We should fix the +checksum:: + + nstatuser@nstat-a:~$ tcprewrite --infile /tmp/paws_pre.pcap --outfile /tmp/paws.pcap --fixcsum + +Send the SYN packet twice:: + + nstatuser@nstat-a:~$ for i in {1..2}; do sudo tcpreplay -i ens3 /tmp/paws.pcap; done + +On nstat-b, check the snmp counter:: + + nstatuser@nstat-b:~$ nstat | grep -i skip + TcpExtTCPACKSkippedPAWS 1 0.0 + +We sent two SYN via tcpreplay, both of them would let PAWS check +failed, the nstat-b replied an ACK for the first SYN, skipped the ACK +for the second SYN, and updated TcpExtTCPACKSkippedPAWS. + +TcpExtTCPACKSkippedSeq +-------------------- +To trigger TcpExtTCPACKSkippedSeq, we send packets which have valid +timestamp (to pass PAWS check) but the sequence number is out of +window. The linux TCP stack would avoid to skip if the packet has +data, so we need a pure ACK packet. To generate such a packet, we +could create two sockets: one on port 9000, another on port 9001. Then +we capture an ACK on port 9001, change the source/destination port +numbers to match the port 9000 socket. Then we could trigger +TcpExtTCPACKSkippedSeq via this packet. + +On nstat-b, open two terminals, run two nc commands to listen on both +port 9000 and port 9001:: + + nstatuser@nstat-b:~$ nc -lkv 9000 + Listening on [0.0.0.0] (family 0, port 9000) + + nstatuser@nstat-b:~$ nc -lkv 9001 + Listening on [0.0.0.0] (family 0, port 9001) + +On nstat-a, run two nc clients:: + + nstatuser@nstat-a:~$ nc -v nstat-b 9000 + Connection to nstat-b 9000 port [tcp/*] succeeded! + + nstatuser@nstat-a:~$ nc -v nstat-b 9001 + Connection to nstat-b 9001 port [tcp/*] succeeded! + +On nstat-a, run tcpdump to capture an ACK:: + + nstatuser@nstat-a:~$ sudo tcpdump -w /tmp/seq_pre.pcap -c 1 dst port 9001 + tcpdump: listening on ens3, link-type EN10MB (Ethernet), capture size 262144 bytes + +On nstat-b, send a packet via the port 9001 socket. E.g. we sent a +string 'foo' in our example:: + + nstatuser@nstat-b:~$ nc -lkv 9001 + Listening on [0.0.0.0] (family 0, port 9001) + Connection from nstat-a 42132 received! + foo + +On nstat-a, the tcpdump should have caputred the ACK. We should check +the source port numbers of the two nc clients:: + + nstatuser@nstat-a:~$ ss -ta '( dport = :9000 || dport = :9001 )' | tee + State Recv-Q Send-Q Local Address:Port Peer Address:Port + ESTAB 0 0 192.168.122.250:50208 192.168.122.251:9000 + ESTAB 0 0 192.168.122.250:42132 192.168.122.251:9001 + +Run tcprewrite, change port 9001 to port 9000, chagne port 42132 to +port 50208:: + + nstatuser@nstat-a:~$ tcprewrite --infile /tmp/seq_pre.pcap --outfile /tmp/seq.pcap -r 9001:9000 -r 42132:50208 --fixcsum + +Now the /tmp/seq.pcap is the packet we need. Send it to nstat-b:: + + nstatuser@nstat-a:~$ for i in {1..2}; do sudo tcpreplay -i ens3 /tmp/seq.pcap; done + +Check TcpExtTCPACKSkippedSeq on nstat-b:: + + nstatuser@nstat-b:~$ nstat | grep -i skip + TcpExtTCPACKSkippedSeq 1 0.0 diff --git a/Documentation/networking/vrf.txt b/Documentation/networking/vrf.txt index 8ff7b4c8f91b..a5f103b083a0 100644 --- a/Documentation/networking/vrf.txt +++ b/Documentation/networking/vrf.txt @@ -103,19 +103,33 @@ VRF device: or to specify the output device using cmsg and IP_PKTINFO. +By default the scope of the port bindings for unbound sockets is +limited to the default VRF. That is, it will not be matched by packets +arriving on interfaces enslaved to an l3mdev and processes may bind to +the same port if they bind to an l3mdev. + TCP & UDP services running in the default VRF context (ie., not bound to any VRF device) can work across all VRF domains by enabling the tcp_l3mdev_accept and udp_l3mdev_accept sysctl options: + sysctl -w net.ipv4.tcp_l3mdev_accept=1 sysctl -w net.ipv4.udp_l3mdev_accept=1 +These options are disabled by default so that a socket in a VRF is only +selected for packets in that VRF. There is a similar option for RAW +sockets, which is enabled by default for reasons of backwards compatibility. +This is so as to specify the output device with cmsg and IP_PKTINFO, but +using a socket not bound to the corresponding VRF. This allows e.g. older ping +implementations to be run with specifying the device but without executing it +in the VRF. This option can be disabled so that packets received in a VRF +context are only handled by a raw socket bound to the VRF, and packets in the +default VRF are only handled by a socket not bound to any VRF: + + sysctl -w net.ipv4.raw_l3mdev_accept=0 + netfilter rules on the VRF device can be used to limit access to services running in the default VRF context as well. -The default VRF does not have limited scope with respect to port bindings. -That is, if a process does a wildcard bind to a port in the default VRF it -owns the port across all VRF domains within the network namespace. - ################################################################################ Using iproute2 for VRFs diff --git a/Documentation/networking/xfrm_device.txt b/Documentation/networking/xfrm_device.txt index 267f55b5f54a..a1c904dc70dc 100644 --- a/Documentation/networking/xfrm_device.txt +++ b/Documentation/networking/xfrm_device.txt @@ -111,9 +111,10 @@ the stack in xfrm_input(). xfrm_state_hold(xs); store the state information into the skb - skb->sp = secpath_dup(skb->sp); - skb->sp->xvec[skb->sp->len++] = xs; - skb->sp->olen++; + sp = secpath_set(skb); + if (!sp) return; + sp->xvec[sp->len++] = xs; + sp->olen++; indicate the success and/or error status of the offload xo = xfrm_offload(skb); diff --git a/Documentation/nvdimm/security.txt b/Documentation/nvdimm/security.txt new file mode 100644 index 000000000000..4c36c05ca98e --- /dev/null +++ b/Documentation/nvdimm/security.txt @@ -0,0 +1,141 @@ +NVDIMM SECURITY +=============== + +1. Introduction +--------------- + +With the introduction of Intel Device Specific Methods (DSM) v1.8 +specification [1], security DSMs are introduced. The spec added the following +security DSMs: "get security state", "set passphrase", "disable passphrase", +"unlock unit", "freeze lock", "secure erase", and "overwrite". A security_ops +data structure has been added to struct dimm in order to support the security +operations and generic APIs are exposed to allow vendor neutral operations. + +2. Sysfs Interface +------------------ +The "security" sysfs attribute is provided in the nvdimm sysfs directory. For +example: +/sys/devices/LNXSYSTM:00/LNXSYBUS:00/ACPI0012:00/ndbus0/nmem0/security + +The "show" attribute of that attribute will display the security state for +that DIMM. The following states are available: disabled, unlocked, locked, +frozen, and overwrite. If security is not supported, the sysfs attribute +will not be visible. + +The "store" attribute takes several commands when it is being written to +in order to support some of the security functionalities: +update <old_keyid> <new_keyid> - enable or update passphrase. +disable <keyid> - disable enabled security and remove key. +freeze - freeze changing of security states. +erase <keyid> - delete existing user encryption key. +overwrite <keyid> - wipe the entire nvdimm. +master_update <keyid> <new_keyid> - enable or update master passphrase. +master_erase <keyid> - delete existing user encryption key. + +3. Key Management +----------------- + +The key is associated to the payload by the DIMM id. For example: +# cat /sys/devices/LNXSYSTM:00/LNXSYBUS:00/ACPI0012:00/ndbus0/nmem0/nfit/id +8089-a2-1740-00000133 +The DIMM id would be provided along with the key payload (passphrase) to +the kernel. + +The security keys are managed on the basis of a single key per DIMM. The +key "passphrase" is expected to be 32bytes long. This is similar to the ATA +security specification [2]. A key is initially acquired via the request_key() +kernel API call during nvdimm unlock. It is up to the user to make sure that +all the keys are in the kernel user keyring for unlock. + +A nvdimm encrypted-key of format enc32 has the description format of: +nvdimm:<bus-provider-specific-unique-id> + +See file ``Documentation/security/keys/trusted-encrypted.rst`` for creating +encrypted-keys of enc32 format. TPM usage with a master trusted key is +preferred for sealing the encrypted-keys. + +4. Unlocking +------------ +When the DIMMs are being enumerated by the kernel, the kernel will attempt to +retrieve the key from the kernel user keyring. This is the only time +a locked DIMM can be unlocked. Once unlocked, the DIMM will remain unlocked +until reboot. Typically an entity (i.e. shell script) will inject all the +relevant encrypted-keys into the kernel user keyring during the initramfs phase. +This provides the unlock function access to all the related keys that contain +the passphrase for the respective nvdimms. It is also recommended that the +keys are injected before libnvdimm is loaded by modprobe. + +5. Update +--------- +When doing an update, it is expected that the existing key is removed from +the kernel user keyring and reinjected as different (old) key. It's irrelevant +what the key description is for the old key since we are only interested in the +keyid when doing the update operation. It is also expected that the new key +is injected with the description format described from earlier in this +document. The update command written to the sysfs attribute will be with +the format: +update <old keyid> <new keyid> + +If there is no old keyid due to a security enabling, then a 0 should be +passed in. + +6. Freeze +--------- +The freeze operation does not require any keys. The security config can be +frozen by a user with root privelege. + +7. Disable +---------- +The security disable command format is: +disable <keyid> + +An key with the current passphrase payload that is tied to the nvdimm should be +in the kernel user keyring. + +8. Secure Erase +--------------- +The command format for doing a secure erase is: +erase <keyid> + +An key with the current passphrase payload that is tied to the nvdimm should be +in the kernel user keyring. + +9. Overwrite +------------ +The command format for doing an overwrite is: +overwrite <keyid> + +Overwrite can be done without a key if security is not enabled. A key serial +of 0 can be passed in to indicate no key. + +The sysfs attribute "security" can be polled to wait on overwrite completion. +Overwrite can last tens of minutes or more depending on nvdimm size. + +An encrypted-key with the current user passphrase that is tied to the nvdimm +should be injected and its keyid should be passed in via sysfs. + +10. Master Update +----------------- +The command format for doing a master update is: +update <old keyid> <new keyid> + +The operating mechanism for master update is identical to update except the +master passphrase key is passed to the kernel. The master passphrase key +is just another encrypted-key. + +This command is only available when security is disabled. + +11. Master Erase +---------------- +The command format for doing a master erase is: +master_erase <current keyid> + +This command has the same operating mechanism as erase except the master +passphrase key is passed to the kernel. The master passphrase key is just +another encrypted-key. + +This command is only available when the master security is enabled, indicated +by the extended security status. + +[1]: http://pmem.io/documents/NVDIMM_DSM_Interface-V1.8.pdf +[2]: http://www.t13.org/documents/UploadedDocuments/docs2006/e05179r4-ACS-SecurityClarifications.pdf diff --git a/Documentation/power/regulator/overview.txt b/Documentation/power/regulator/overview.txt index 40ca2d6e2742..721b4739ec32 100644 --- a/Documentation/power/regulator/overview.txt +++ b/Documentation/power/regulator/overview.txt @@ -22,7 +22,7 @@ Nomenclature Some terms used in this document:- o Regulator - Electronic device that supplies power to other devices. - Most regulators can enable and disable their output whilst + Most regulators can enable and disable their output while some can control their output voltage and or current. Input Voltage -> Regulator -> Output Voltage diff --git a/Documentation/process/1.Intro.rst b/Documentation/process/1.Intro.rst index e782ae2eef58..c3d0270bbfb3 100644 --- a/Documentation/process/1.Intro.rst +++ b/Documentation/process/1.Intro.rst @@ -1,3 +1,5 @@ +.. _development_process_intro: + Introduction ============ diff --git a/Documentation/process/4.Coding.rst b/Documentation/process/4.Coding.rst index eb4b185d168c..cfe264889447 100644 --- a/Documentation/process/4.Coding.rst +++ b/Documentation/process/4.Coding.rst @@ -315,7 +315,8 @@ variety of potential coding problems; it can also propose fixes for those problems. Quite a few "semantic patches" for the kernel have been packaged under the scripts/coccinelle directory; running "make coccicheck" will run through those semantic patches and report on any problems found. See -Documentation/dev-tools/coccinelle.rst for more information. +:ref:`Documentation/dev-tools/coccinelle.rst <devtools_coccinelle>` +for more information. Other kinds of portability errors are best found by compiling your code for other architectures. If you do not happen to have an S/390 system or a diff --git a/Documentation/process/5.Posting.rst b/Documentation/process/5.Posting.rst index c418c5d6cae4..4213e580f273 100644 --- a/Documentation/process/5.Posting.rst +++ b/Documentation/process/5.Posting.rst @@ -9,9 +9,10 @@ kernel. Unsurprisingly, the kernel development community has evolved a set of conventions and procedures which are used in the posting of patches; following them will make life much easier for everybody involved. This document will attempt to cover these expectations in reasonable detail; -more information can also be found in the files process/submitting-patches.rst, -process/submitting-drivers.rst, and process/submit-checklist.rst in the kernel -documentation directory. +more information can also be found in the files +:ref:`Documentation/process/submitting-patches.rst <submittingpatches>`, +:ref:`Documentation/process/submitting-drivers.rst <submittingdrivers>` +and :ref:`Documentation/process/submit-checklist.rst <submitchecklist>`. When to post @@ -198,8 +199,10 @@ pass it to diff with the "-X" option. The tags mentioned above are used to describe how various developers have been associated with the development of this patch. They are described in -detail in the process/submitting-patches.rst document; what follows here is a -brief summary. Each of these lines has the format: +detail in +the :ref:`Documentation/process/submitting-patches.rst <submittingpatches>` +document; what follows here is a brief summary. Each of these lines has +the format: :: @@ -210,8 +213,8 @@ The tags in common use are: - Signed-off-by: this is a developer's certification that he or she has the right to submit the patch for inclusion into the kernel. It is an agreement to the Developer's Certificate of Origin, the full text of - which can be found in Documentation/process/submitting-patches.rst. Code - without a proper signoff cannot be merged into the mainline. + which can be found in :ref:`Documentation/process/submitting-patches.rst <submittingpatches>` + Code without a proper signoff cannot be merged into the mainline. - Co-developed-by: states that the patch was also created by another developer along with the original author. This is useful at times when multiple @@ -226,7 +229,7 @@ The tags in common use are: it to work. - Reviewed-by: the named developer has reviewed the patch for correctness; - see the reviewer's statement in Documentation/process/submitting-patches.rst + see the reviewer's statement in :ref:`Documentation/process/submitting-patches.rst <submittingpatches>` for more detail. - Reported-by: names a user who reported a problem which is fixed by this @@ -253,8 +256,8 @@ take care of: be examined in any detail. If there is any doubt at all, mail the patch to yourself and convince yourself that it shows up intact. - Documentation/process/email-clients.rst has some helpful hints on making - specific mail clients work for sending patches. + :ref:`Documentation/process/email-clients.rst <email_clients>` has some + helpful hints on making specific mail clients work for sending patches. - Are you sure your patch is free of silly mistakes? You should always run patches through scripts/checkpatch.pl and address the complaints it diff --git a/Documentation/process/8.Conclusion.rst b/Documentation/process/8.Conclusion.rst index 1c7f54cd0261..8395aa2c1f3a 100644 --- a/Documentation/process/8.Conclusion.rst +++ b/Documentation/process/8.Conclusion.rst @@ -5,9 +5,10 @@ For more information There are numerous sources of information on Linux kernel development and related topics. First among those will always be the Documentation -directory found in the kernel source distribution. The top-level process/howto.rst -file is an important starting point; process/submitting-patches.rst and -process/submitting-drivers.rst are also something which all kernel developers should +directory found in the kernel source distribution. The top-level :ref:`process/howto.rst <process_howto>` +file is an important starting point; :ref:`process/submitting-patches.rst <submittingpatches>` +and :ref:`process/submitting-drivers.rst <submittingdrivers>` +are also something which all kernel developers should read. Many internal kernel APIs are documented using the kerneldoc mechanism; "make htmldocs" or "make pdfdocs" can be used to generate those documents in HTML or PDF format (though the version of TeX shipped by some diff --git a/Documentation/process/adding-syscalls.rst b/Documentation/process/adding-syscalls.rst index 88a7d5c8bb2f..1c3a840d06b9 100644 --- a/Documentation/process/adding-syscalls.rst +++ b/Documentation/process/adding-syscalls.rst @@ -1,3 +1,6 @@ + +.. _addsyscalls: + Adding a New System Call ======================== diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst index d1bf143b446f..18735dc460a0 100644 --- a/Documentation/process/changes.rst +++ b/Documentation/process/changes.rst @@ -326,7 +326,7 @@ Kernel documentation Sphinx ------ -Please see :ref:`sphinx_install` in ``Documentation/doc-guide/sphinx.rst`` +Please see :ref:`sphinx_install` in :ref:`Documentation/doc-guide/sphinx.rst <sphinxdoc>` for details about Sphinx requirements. Getting updated software diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst index 4e7c0a1c427a..277c113376a6 100644 --- a/Documentation/process/coding-style.rst +++ b/Documentation/process/coding-style.rst @@ -1075,5 +1075,5 @@ gcc internals and indent, all available from http://www.gnu.org/manual/ WG14 is the international standardization working group for the programming language C, URL: http://www.open-std.org/JTC1/SC22/WG14/ -Kernel process/coding-style.rst, by greg@kroah.com at OLS 2002: +Kernel :ref:`process/coding-style.rst <codingstyle>`, by greg@kroah.com at OLS 2002: http://www.kroah.com/linux/talks/ols_2002_kernel_codingstyle_talk/html/ diff --git a/Documentation/process/howto.rst b/Documentation/process/howto.rst index dcb25f94188e..58b2f46c4f98 100644 --- a/Documentation/process/howto.rst +++ b/Documentation/process/howto.rst @@ -1,3 +1,5 @@ +.. _process_howto: + HOWTO do Linux kernel development ================================= @@ -296,9 +298,9 @@ two weeks, but it can be longer if there are no pressing problems. A security-related problem, instead, can cause a release to happen almost instantly. -The file Documentation/process/stable-kernel-rules.rst in the kernel tree -documents what kinds of changes are acceptable for the -stable tree, and -how the release process works. +The file :ref:`Documentation/process/stable-kernel-rules.rst <stable_kernel_rules>` +in the kernel tree documents what kinds of changes are acceptable for +the -stable tree, and how the release process works. 4.x -git patches ~~~~~~~~~~~~~~~~ @@ -358,7 +360,8 @@ tool. For details on how to use the kernel bugzilla, please see: https://bugzilla.kernel.org/page.cgi?id=faq.html -The file admin-guide/reporting-bugs.rst in the main kernel source directory has a good +The file :ref:`admin-guide/reporting-bugs.rst <reportingbugs>` +in the main kernel source directory has a good template for how to report a possible kernel bug, and details what kind of information is needed by the kernel developers to help track down the problem. @@ -424,7 +427,7 @@ add your statements between the individual quoted sections instead of writing at the top of the mail. If you add patches to your mail, make sure they are plain readable text -as stated in Documentation/process/submitting-patches.rst. +as stated in :ref:`Documentation/process/submitting-patches.rst <submittingpatches>`. Kernel developers don't want to deal with attachments or compressed patches; they may want to comment on individual lines of your patch, which works only that way. Make sure you diff --git a/Documentation/process/kernel-driver-statement.rst b/Documentation/process/kernel-driver-statement.rst index e78452c2164c..a849790a68bc 100644 --- a/Documentation/process/kernel-driver-statement.rst +++ b/Documentation/process/kernel-driver-statement.rst @@ -1,3 +1,5 @@ +.. _process_statement_driver: + Kernel Driver Statement ----------------------- diff --git a/Documentation/process/kernel-enforcement-statement.rst b/Documentation/process/kernel-enforcement-statement.rst index 6816c12d6956..e5a1be476047 100644 --- a/Documentation/process/kernel-enforcement-statement.rst +++ b/Documentation/process/kernel-enforcement-statement.rst @@ -1,4 +1,6 @@ -Linux Kernel Enforcement Statement +.. _process_statement_kernel: + +Linux Kernel Enforcement Statement ---------------------------------- As developers of the Linux kernel, we have a keen interest in how our software diff --git a/Documentation/process/magic-number.rst b/Documentation/process/magic-number.rst index 633be1043690..547bbf28e615 100644 --- a/Documentation/process/magic-number.rst +++ b/Documentation/process/magic-number.rst @@ -1,3 +1,5 @@ +.. _magicnumbers: + Linux magic numbers =================== diff --git a/Documentation/process/management-style.rst b/Documentation/process/management-style.rst index 85ef8ca8f639..186753ff3d2d 100644 --- a/Documentation/process/management-style.rst +++ b/Documentation/process/management-style.rst @@ -5,8 +5,9 @@ Linux kernel management style This is a short document describing the preferred (or made up, depending on who you ask) management style for the linux kernel. It's meant to -mirror the process/coding-style.rst document to some degree, and mainly written to -avoid answering [#f1]_ the same (or similar) questions over and over again. +mirror the :ref:`process/coding-style.rst <codingstyle>` document to some +degree, and mainly written to avoid answering [#f1]_ the same (or similar) +questions over and over again. Management style is very personal and much harder to quantify than simple coding style rules, so this document may or may not have anything diff --git a/Documentation/process/submitting-drivers.rst b/Documentation/process/submitting-drivers.rst index b38bf2054ce3..58bc047e7b95 100644 --- a/Documentation/process/submitting-drivers.rst +++ b/Documentation/process/submitting-drivers.rst @@ -16,7 +16,8 @@ you should probably talk to XFree86 (http://www.xfree86.org/) and/or X.Org Oh, and we don't really recommend submitting changes to XFree86 :) -Also read the Documentation/process/submitting-patches.rst document. +Also read the :ref:`Documentation/process/submitting-patches.rst <submittingpatches>` +document. Allocating Device Numbers @@ -27,7 +28,8 @@ by the Linux assigned name and number authority (currently this is Torben Mathiasen). The site is http://www.lanana.org/. This also deals with allocating numbers for devices that are not going to be submitted to the mainstream kernel. -See Documentation/admin-guide/devices.rst for more information on this. +See :ref:`Documentation/admin-guide/devices.rst <admin_devices>` +for more information on this. If you don't use assigned numbers then when your device is submitted it will be given an assigned number even if that is different from values you may @@ -117,7 +119,7 @@ PM support: anything. For the driver testing instructions see Documentation/power/drivers-testing.txt and for a relatively complete overview of the power management issues related to - drivers see Documentation/driver-api/pm/devices.rst. + drivers see :ref:`Documentation/driver-api/pm/devices.rst <driverapi_pm_devices>`. Control: In general if there is active maintenance of a driver by diff --git a/Documentation/s390/3270.ChangeLog b/Documentation/s390/3270.ChangeLog index 031c36081946..ecaf60b6c381 100644 --- a/Documentation/s390/3270.ChangeLog +++ b/Documentation/s390/3270.ChangeLog @@ -16,7 +16,7 @@ Sep 2002: Dynamically get 3270 input buffer Sep 2002: Fix tubfs kmalloc()s * Do read and write lengths correctly in fs3270_read() - and fs3270_write(), whilst never asking kmalloc() + and fs3270_write(), while never asking kmalloc() for more than 0x800 bytes. Affects tubfs.c and tubio.h. Sep 2002: Recognize 3270 control unit type 3174 diff --git a/Documentation/scsi/scsi-parameters.txt b/Documentation/scsi/scsi-parameters.txt index 92999d4e0cb8..25a4b4cf04a6 100644 --- a/Documentation/scsi/scsi-parameters.txt +++ b/Documentation/scsi/scsi-parameters.txt @@ -97,11 +97,6 @@ parameters may be changed at runtime by the command allowing boot to proceed. none ignores them, expecting user space to do the scan. - scsi_mod.use_blk_mq= - [SCSI] use blk-mq I/O path by default - See SCSI_MQ_DEFAULT in drivers/scsi/Kconfig. - Format: <y/n> - sim710= [SCSI,HW] See header of drivers/scsi/sim710.c. diff --git a/Documentation/scsi/scsi_mid_low_api.txt b/Documentation/scsi/scsi_mid_low_api.txt index 177c031763c0..c1dd4939f4ae 100644 --- a/Documentation/scsi/scsi_mid_low_api.txt +++ b/Documentation/scsi/scsi_mid_low_api.txt @@ -1098,8 +1098,6 @@ of interest: unchecked_isa_dma - 1=>only use bottom 16 MB of ram (ISA DMA addressing restriction), 0=>can use full 32 bit (or better) DMA address space - use_clustering - 1=>SCSI commands in mid level's queue can be merged, - 0=>disallow SCSI command merging no_async_abort - 1=>Asynchronous aborts are not supported 0=>Timed-out commands will be aborted asynchronously hostt - pointer to driver's struct scsi_host_template from which diff --git a/Documentation/security/credentials.rst b/Documentation/security/credentials.rst index 5bb7125faeee..282e79feee6a 100644 --- a/Documentation/security/credentials.rst +++ b/Documentation/security/credentials.rst @@ -291,7 +291,7 @@ for example), it must be considered immutable, barring two exceptions: 1. The reference count may be altered. - 2. Whilst the keyring subscriptions of a set of credentials may not be + 2. While the keyring subscriptions of a set of credentials may not be changed, the keyrings subscribed to may have their contents altered. To catch accidental credential alteration at compile time, struct task_struct @@ -358,7 +358,7 @@ Once a reference has been obtained, it must be released with ``put_cred()``, Accessing Another Task's Credentials ------------------------------------ -Whilst a task may access its own credentials without the need for locking, the +While a task may access its own credentials without the need for locking, the same is not true of a task wanting to access another task's credentials. It must use the RCU read lock and ``rcu_dereference()``. @@ -382,7 +382,7 @@ This should be used inside the RCU read lock, as in the following example:: } Should it be necessary to hold another task's credentials for a long period of -time, and possibly to sleep whilst doing so, then the caller should get a +time, and possibly to sleep while doing so, then the caller should get a reference on them using:: const struct cred *get_task_cred(struct task_struct *task); @@ -442,7 +442,7 @@ duplicate of the current process's credentials, returning with the mutex still held if successful. It returns NULL if not successful (out of memory). The mutex prevents ``ptrace()`` from altering the ptrace state of a process -whilst security checks on credentials construction and changing is taking place +while security checks on credentials construction and changing is taking place as the ptrace state may alter the outcome, particularly in the case of ``execve()``. diff --git a/Documentation/security/keys/request-key.rst b/Documentation/security/keys/request-key.rst index 21e27238cec6..600ad67d1707 100644 --- a/Documentation/security/keys/request-key.rst +++ b/Documentation/security/keys/request-key.rst @@ -132,7 +132,7 @@ Negative Instantiation And Rejection Rather than instantiating a key, it is possible for the possessor of an authorisation key to negatively instantiate a key that's under construction. This is a short duration placeholder that causes any attempt at re-requesting -the key whilst it exists to fail with error ENOKEY if negated or the specified +the key while it exists to fail with error ENOKEY if negated or the specified error if rejected. This is provided to prevent excessive repeated spawning of /sbin/request-key diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst index 3bb24e09a332..7b35fcb58933 100644 --- a/Documentation/security/keys/trusted-encrypted.rst +++ b/Documentation/security/keys/trusted-encrypted.rst @@ -18,10 +18,33 @@ integrity verifications match. A loaded Trusted Key can be updated with new when the kernel and initramfs are updated. The same key can have many saved blobs under different PCR values, so multiple boots are easily supported. +TPM 1.2 +------- + By default, trusted keys are sealed under the SRK, which has the default authorization value (20 zeros). This can be set at takeownership time with the trouser's utility: "tpm_takeownership -u -z". +TPM 2.0 +------- + +The user must first create a storage key and make it persistent, so the key is +available after reboot. This can be done using the following commands. + +With the IBM TSS 2 stack:: + + #> tsscreateprimary -hi o -st + Handle 80000000 + #> tssevictcontrol -hi o -ho 80000000 -hp 81000001 + +Or with the Intel TSS 2 stack:: + + #> tpm2_createprimary --hierarchy o -G rsa2048 -o key.ctxt + [...] + handle: 0x800000FF + #> tpm2_evictcontrol -c key.ctxt -p 0x81000001 + persistentHandle: 0x81000001 + Usage:: keyctl add trusted name "new keylen [options]" ring @@ -30,7 +53,9 @@ Usage:: keyctl print keyid options: - keyhandle= ascii hex value of sealing key default 0x40000000 (SRK) + keyhandle= ascii hex value of sealing key + TPM 1.2: default 0x40000000 (SRK) + TPM 2.0: no default; must be passed every time keyauth= ascii hex auth for sealing key default 0x00...i (40 ascii zeros) blobauth= ascii hex auth for sealed data default 0x00... @@ -76,7 +101,7 @@ Usage:: Where:: - format:= 'default | ecryptfs' + format:= 'default | ecryptfs | enc32' key-type:= 'trusted' | 'user' @@ -84,6 +109,10 @@ Examples of trusted and encrypted key usage: Create and save a trusted key named "kmk" of length 32 bytes:: +Note: When using a TPM 2.0 with a persistent key with handle 0x81000001, +append 'keyhandle=0x81000001' to statements between quotes, such as +"new 32 keyhandle=0x81000001". + $ keyctl add trusted kmk "new 32" @u 440502848 @@ -173,3 +202,7 @@ are anticipated. In particular the new format 'ecryptfs' has been defined in in order to use encrypted keys to mount an eCryptfs filesystem. More details about the usage can be found in the file ``Documentation/security/keys/ecryptfs.rst``. + +Another new format 'enc32' has been defined in order to support encrypted keys +with payload size of 32 bytes. This will initially be used for nvdimm security +but may expand to other usages that require 32 bytes payload. diff --git a/Documentation/serial/serial-rs485.txt b/Documentation/serial/serial-rs485.txt index 389fcd4759e9..ce0c1a9b8aab 100644 --- a/Documentation/serial/serial-rs485.txt +++ b/Documentation/serial/serial-rs485.txt @@ -75,7 +75,7 @@ /* Set rts delay after send, if needed: */ rs485conf.delay_rts_after_send = ...; - /* Set this flag if you want to receive data even whilst sending data */ + /* Set this flag if you want to receive data even while sending data */ rs485conf.flags |= SER_RS485_RX_DURING_TX; if (ioctl (fd, TIOCSRS485, &rs485conf) < 0) { diff --git a/Documentation/sh/new-machine.txt b/Documentation/sh/new-machine.txt index f0354164cb0e..e0961a66130b 100644 --- a/Documentation/sh/new-machine.txt +++ b/Documentation/sh/new-machine.txt @@ -116,7 +116,6 @@ might look something like: * arch/sh/boards/vapor/setup.c - Setup code for imaginary board */ #include <linux/init.h> -#include <asm/rtc.h> /* for board_time_init() */ const char *get_system_type(void) { @@ -132,13 +131,6 @@ int __init platform_setup(void) * this board. */ - /* - * Presume all FooTech boards have the same broken timer, - * and also presume that we've defined foo_timer_init to - * do something useful. - */ - board_time_init = foo_timer_init; - /* Start-up imaginary PCI ... */ /* And whatever else ... */ diff --git a/Documentation/sound/soc/dai.rst b/Documentation/sound/soc/dai.rst index 55820e51708f..2e99183a7a47 100644 --- a/Documentation/sound/soc/dai.rst +++ b/Documentation/sound/soc/dai.rst @@ -24,7 +24,7 @@ I2S === I2S is a common 4 wire DAI used in HiFi, STB and portable devices. The Tx and -Rx lines are used for audio transmission, whilst the bit clock (BCLK) and +Rx lines are used for audio transmission, while the bit clock (BCLK) and left/right clock (LRC) synchronise the link. I2S is flexible in that either the controller or CODEC can drive (master) the BCLK and LRC clock lines. Bit clock usually varies depending on the sample rate and the master system clock @@ -49,9 +49,9 @@ PCM PCM is another 4 wire interface, very similar to I2S, which can support a more flexible protocol. It has bit clock (BCLK) and sync (SYNC) lines that are used -to synchronise the link whilst the Tx and Rx lines are used to transmit and +to synchronise the link while the Tx and Rx lines are used to transmit and receive the audio data. Bit clock usually varies depending on sample rate -whilst sync runs at the sample rate. PCM also supports Time Division +while sync runs at the sample rate. PCM also supports Time Division Multiplexing (TDM) in that several devices can use the bus simultaneously (this is sometimes referred to as network mode). diff --git a/Documentation/sound/soc/dpcm.rst b/Documentation/sound/soc/dpcm.rst index fe61e02277f8..f6845b2278ea 100644 --- a/Documentation/sound/soc/dpcm.rst +++ b/Documentation/sound/soc/dpcm.rst @@ -218,7 +218,7 @@ like a BT phone call :- * * <----DAI5-----> FM ************* -This allows the host CPU to sleep whilst the DSP, MODEM DAI and the BT DAI are +This allows the host CPU to sleep while the DSP, MODEM DAI and the BT DAI are still in operation. A BE DAI link can also set the codec to a dummy device if the code is a device diff --git a/Documentation/static-keys.txt b/Documentation/static-keys.txt index ab16efe0c79d..d68135560895 100644 --- a/Documentation/static-keys.txt +++ b/Documentation/static-keys.txt @@ -156,7 +156,7 @@ or increment/decrement function. Note that switching branches results in some locks being taken, particularly the CPU hotplug lock (in order to avoid races against -CPUs being brought in the kernel whilst the kernel is getting +CPUs being brought in the kernel while the kernel is getting patched). Calling the static key API from within a hotplug notifier is thus a sure deadlock recipe. In order to still allow use of the functionnality, the following functions are provided: diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 7d73882e2c27..187ce4f599a2 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -63,6 +63,7 @@ Currently, these files are in /proc/sys/vm: - swappiness - user_reserve_kbytes - vfs_cache_pressure +- watermark_boost_factor - watermark_scale_factor - zone_reclaim_mode @@ -856,6 +857,26 @@ ten times more freeable objects than there are. ============================================================= +watermark_boost_factor: + +This factor controls the level of reclaim when memory is being fragmented. +It defines the percentage of the high watermark of a zone that will be +reclaimed if pages of different mobility are being mixed within pageblocks. +The intent is that compaction has less work to do in the future and to +increase the success rate of future high-order allocations such as SLUB +allocations, THP and hugetlbfs pages. + +To make it sensible with respect to the watermark_scale_factor parameter, +the unit is in fractions of 10,000. The default value of 15,000 means +that up to 150% of the high watermark will be reclaimed in the event of +a pageblock being mixed due to fragmentation. The level of reclaim is +determined by the number of fragmentation events that occurred in the +recent past. If this value is smaller than a pageblock then a pageblocks +worth of pages will be reclaimed (e.g. 2MB on 64-bit x86). A boost factor +of 0 will disable the feature. + +============================================================= + watermark_scale_factor: This factor controls the aggressiveness of kswapd. It defines the diff --git a/Documentation/thermal/power_allocator.txt b/Documentation/thermal/power_allocator.txt index a1ce2235f121..9fb0ff06dca9 100644 --- a/Documentation/thermal/power_allocator.txt +++ b/Documentation/thermal/power_allocator.txt @@ -110,7 +110,7 @@ the permitted thermal "ramp" of the system. For instance, a lower `k_pu` value will provide a slower ramp, at the cost of capping available capacity at a low temperature. On the other hand, a high value of `k_pu` will result in the governor granting very high power -whilst temperature is low, and may lead to temperature overshooting. +while temperature is low, and may lead to temperature overshooting. The default value for `k_pu` is: diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst index f82434f2795e..0131df7f5968 100644 --- a/Documentation/trace/ftrace.rst +++ b/Documentation/trace/ftrace.rst @@ -24,13 +24,13 @@ It can be used for debugging or analyzing latencies and performance issues that take place outside of user-space. Although ftrace is typically considered the function tracer, it -is really a frame work of several assorted tracing utilities. +is really a framework of several assorted tracing utilities. There's latency tracing to examine what occurs between interrupts disabled and enabled, as well as for preemption and from a time a task is woken to the task is actually scheduled in. One of the most common uses of ftrace is the event tracing. -Through out the kernel is hundreds of static event points that +Throughout the kernel is hundreds of static event points that can be enabled via the tracefs file system to see what is going on in certain parts of the kernel. @@ -462,7 +462,7 @@ of ftrace. Here is a list of some of the key files: mono_raw: This is the raw monotonic clock (CLOCK_MONOTONIC_RAW) - which is montonic but is not subject to any rate adjustments + which is monotonic but is not subject to any rate adjustments and ticks at the same rate as the hardware clocksource. boot: @@ -914,8 +914,8 @@ The above is mostly meaningful for kernel developers. current trace and the next trace. - '$' - greater than 1 second - - '@' - greater than 100 milisecond - - '*' - greater than 10 milisecond + - '@' - greater than 100 millisecond + - '*' - greater than 10 millisecond - '#' - greater than 1000 microsecond - '!' - greater than 100 microsecond - '+' - greater than 10 microsecond @@ -2541,7 +2541,7 @@ At compile time every C file object is run through the recordmcount program (located in the scripts directory). This program will parse the ELF headers in the C object to find all the locations in the .text section that call mcount. Starting -with gcc verson 4.6, the -mfentry has been added for x86, which +with gcc version 4.6, the -mfentry has been added for x86, which calls "__fentry__" instead of "mcount". Which is called before the creation of the stack frame. @@ -2978,7 +2978,7 @@ The following commands are supported: When the function is hit, it will dump the contents of the ftrace ring buffer to the console. This is useful if you need to debug something, and want to dump the trace when a certain function - is hit. Perhaps its a function that is called before a tripple + is hit. Perhaps it's a function that is called before a triple fault happens and does not allow you to get a regular dump. - cpudump: diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst index 306997941ba1..6b4107cf4b98 100644 --- a/Documentation/trace/index.rst +++ b/Documentation/trace/index.rst @@ -22,3 +22,4 @@ Linux Tracing Technologies hwlat_detector intel_th stm + sys-t diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst index 47e765c2f2c3..235ce2ab131a 100644 --- a/Documentation/trace/kprobetrace.rst +++ b/Documentation/trace/kprobetrace.rst @@ -20,6 +20,9 @@ current_tracer. Instead of that, add probe points via /sys/kernel/debug/tracing/kprobe_events, and enable it via /sys/kernel/debug/tracing/events/kprobes/<EVENT>/enable. +You can also use /sys/kernel/debug/tracing/dynamic_events instead of +kprobe_events. That interface will provide unified access to other +dynamic events too. Synopsis of kprobe_events ------------------------- diff --git a/Documentation/trace/uprobetracer.rst b/Documentation/trace/uprobetracer.rst index d0822811527a..4c3bfde2ba47 100644 --- a/Documentation/trace/uprobetracer.rst +++ b/Documentation/trace/uprobetracer.rst @@ -18,6 +18,10 @@ current_tracer. Instead of that, add probe points via However unlike kprobe-event tracer, the uprobe event interface expects the user to calculate the offset of the probepoint in the object. +You can also use /sys/kernel/debug/tracing/dynamic_events instead of +uprobe_events. That interface will provide unified access to other +dynamic events too. + Synopsis of uprobe_tracer ------------------------- :: diff --git a/Documentation/translations/it_IT/admin-guide/README.rst b/Documentation/translations/it_IT/admin-guide/README.rst new file mode 100644 index 000000000000..80f5ffc94a9e --- /dev/null +++ b/Documentation/translations/it_IT/admin-guide/README.rst @@ -0,0 +1,12 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/admin-guide/README.rst <readme>` + +.. _it_readme: + +Rilascio del kernel Linux 4.x <http://kernel.org/> +=================================================== + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/admin-guide/security-bugs.rst b/Documentation/translations/it_IT/admin-guide/security-bugs.rst new file mode 100644 index 000000000000..18a5822c7d9a --- /dev/null +++ b/Documentation/translations/it_IT/admin-guide/security-bugs.rst @@ -0,0 +1,12 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/admin-guide/security-bugs.rst <securitybugs>` + +.. _it_securitybugs: + +Bachi di sicurezza +================== + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/doc-guide/kernel-doc.rst b/Documentation/translations/it_IT/doc-guide/kernel-doc.rst index 2bf1c1e2f394..a4ecd8f27631 100644 --- a/Documentation/translations/it_IT/doc-guide/kernel-doc.rst +++ b/Documentation/translations/it_IT/doc-guide/kernel-doc.rst @@ -107,7 +107,7 @@ macro simil-funzioni è il seguente:: * Context: Describes whether the function can sleep, what locks it takes, * releases, or expects to be held. It can extend over multiple * lines. - * Return: Describe the return value of foobar. + * Return: Describe the return value of function_name. * * The return value description can also have multiple paragraphs, and should * be placed at the end of the comment block. diff --git a/Documentation/translations/it_IT/index.rst b/Documentation/translations/it_IT/index.rst index 898a7823a6f4..ea9b2916b3e4 100644 --- a/Documentation/translations/it_IT/index.rst +++ b/Documentation/translations/it_IT/index.rst @@ -86,6 +86,7 @@ vostre modifiche molto più semplice .. toctree:: :maxdepth: 2 + process/index doc-guide/index kernel-hacking/index diff --git a/Documentation/translations/it_IT/kernel-hacking/locking.rst b/Documentation/translations/it_IT/kernel-hacking/locking.rst index 753643622c23..0ef31666663b 100644 --- a/Documentation/translations/it_IT/kernel-hacking/locking.rst +++ b/Documentation/translations/it_IT/kernel-hacking/locking.rst @@ -593,8 +593,8 @@ l'opzione ``GFP_KERNEL`` che è permessa solo in contesto utente. Ho supposto che :c:func:`cache_add()` venga chiamata dal contesto utente, altrimenti questa opzione deve diventare un parametro di :c:func:`cache_add()`. -Exposing Objects Outside This File ----------------------------------- +Esporre gli oggetti al di fuori del file +---------------------------------------- Se i vostri oggetti contengono più informazioni, potrebbe non essere sufficiente copiare i dati avanti e indietro: per esempio, altre parti del diff --git a/Documentation/translations/it_IT/process/1.Intro.rst b/Documentation/translations/it_IT/process/1.Intro.rst new file mode 100644 index 000000000000..c1be6dc398a7 --- /dev/null +++ b/Documentation/translations/it_IT/process/1.Intro.rst @@ -0,0 +1,297 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/1.Intro.rst <development_process_intro>` +:Translator: Alessia Mantegazza <amantegazza@vaga.pv.it> + +.. _it_development_intro: + +Introduzione +============ + +Riepilogo generale +------------------ + +Il resto di questa sezione riguarda il processo di sviluppo del kernel e +quella sorta di frustrazione che gli sviluppatori e i loro datori di lavoro +potrebbero dover affrontare. Ci sono molte ragioni per le quali del codice +per il kernel debba essere incorporato nel kernel ufficiale, fra le quali: +disponibilità immediata agli utilizzatori, supporto della comunità in +differenti modalità, e la capacità di influenzare la direzione dello sviluppo +del kernel. +Il codice che contribuisce al kernel Linux deve essere reso disponibile sotto +una licenza GPL-compatibile. + +La sezione :ref:`it_development_process` introduce il processo di sviluppo, +il ciclo di rilascio del kernel, ed i meccanismi della finestra +d'incorporazione. Il capitolo copre le varie fasi di una modifica: sviluppo, +revisione e ciclo d'incorporazione. Ci sono alcuni dibattiti su strumenti e +liste di discussione. Gli sviluppatori che sono in attesa di poter sviluppare +qualcosa per il kernel sono invitati ad individuare e sistemare bachi come +esercizio iniziale. + +La sezione :ref:`it_development_early_stage` copre i primi stadi della +pianificazione di un progetto di sviluppo, con particolare enfasi sul +coinvolgimento della comunità, il prima possibile. + +La sezione :ref:`it_development_coding` riguarda il processo di scrittura +del codice. Qui, sono esposte le diverse insidie che sono state già affrontate +da altri sviluppatori. Il capitolo copre anche alcuni dei requisiti per le +modifiche, ed esiste un'introduzione ad alcuni strumenti che possono aiutarvi +nell'assicurarvi che le modifiche per il kernel siano corrette. + +La sezione :ref:`it_development_posting` parla del processo di pubblicazione +delle modifiche per la revisione. Per essere prese in considerazione dalla +comunità di sviluppo, le modifiche devono essere propriamente formattate ed +esposte, e devono essere inviate nel posto giusto. Seguire i consigli presenti +in questa sezione dovrebbe essere d'aiuto nell'assicurare la migliore +accoglienza possibile del vostro lavoro. + +La sezione :ref:`it_development_followthrough` copre ciò che accade dopo +la pubblicazione delle modifiche; a questo punto il lavoro è lontano +dall'essere concluso. Lavorare con i revisori è una parte cruciale del +processo di sviluppo; questa sezione offre una serie di consigli su come +evitare problemi in questa importante fase. Gli sviluppatori sono diffidenti +nell'affermare che il lavoro è concluso quando una modifica è incorporata nei +sorgenti principali. + +La sezione :ref:`it_development_advancedtopics` introduce un paio di argomenti +"avanzati": gestire le modifiche con git e controllare le modifiche pubblicate +da altri. + +La sezione :ref:`it_development_conclusion` chiude il documento con dei +riferimenti ad altre fonti che forniscono ulteriori informazioni sullo sviluppo +del kernel. + +Di cosa parla questo documento +------------------------------ + +Il kernel Linux, ha oltre 8 milioni di linee di codice e ben oltre 1000 +contributori ad ogni rilascio; è uno dei più vasti e più attivi software +liberi progettati mai esistiti. Sin dal sul modesto inizio nel 1991, +questo kernel si è evoluto nel miglior componente per sistemi operativi +che fanno funzionare piccoli riproduttori musicali, PC, grandi super computer +e tutte le altre tipologie di sistemi fra questi estremi. È una soluzione +robusta, efficiente ed adattabile a praticamente qualsiasi situazione. + +Con la crescita di Linux è arrivato anche un aumento di sviluppatori +(ed aziende) desiderosi di partecipare a questo sviluppo. I produttori di +hardware vogliono assicurarsi che il loro prodotti siano supportati da Linux, +rendendo questi prodotti attrattivi agli utenti Linux. I produttori di +sistemi integrati, che usano Linux come componente di un prodotto integrato, +vogliono che Linux sia capace ed adeguato agli obiettivi ed il più possibile +alla mano. Fornitori ed altri produttori di software che basano i propri +prodotti su Linux hanno un chiaro interesse verso capacità, prestazioni ed +affidabilità del kernel Linux. E gli utenti finali, anche, spesso vorrebbero +cambiare Linux per renderlo più aderente alle proprie necessità. + +Una delle caratteristiche più coinvolgenti di Linux è quella dell'accessibilità +per gli sviluppatori; chiunque con le capacità richieste può migliorare +Linux ed influenzarne la direzione di sviluppo. Prodotti non open-source non +possono offrire questo tipo di apertura, che è una caratteristica del software +libero. Ma, anzi, il kernel è persino più aperto rispetto a molti altri +progetti di software libero. Un classico ciclo di sviluppo trimestrale può +coinvolgere 1000 sviluppatori che lavorano per più di 100 differenti aziende +(o per nessuna azienda). + +Lavorare con la comunità di sviluppo del kernel non è particolarmente +difficile. Ma, ciononostante, diversi potenziali contributori hanno trovato +delle difficoltà quando hanno cercato di lavorare sul kernel. La comunità del +kernel utilizza un proprio modo di operare che gli permette di funzionare +agevolmente (e genera un prodotto di alta qualità) in un ambiente dove migliaia +di stringhe di codice sono modificate ogni giorni. Quindi non deve sorprendere +che il processo di sviluppo del kernel differisca notevolmente dai metodi di +sviluppo privati. + +Il processo di sviluppo del Kernel può, dall'altro lato, risultare +intimidatorio e strano ai nuovi sviluppatori, ma ha dietro di se buone ragioni +e solide esperienze. Uno sviluppatore che non comprende i modi della comunità +del kernel (o, peggio, che cerchi di aggirarli o violarli) avrà un'esperienza +deludente nel proprio bagaglio. La comunità di sviluppo, sebbene sia utile +a coloro che cercano di imparare, ha poco tempo da dedicare a coloro che non +ascoltano o coloro che non sono interessati al processo di sviluppo. + +Si spera che coloro che leggono questo documento saranno in grado di evitare +queste esperienze spiacevoli. C'è molto materiale qui, ma lo sforzo della +lettura sarà ripagato in breve tempo. La comunità di sviluppo ha sempre +bisogno di sviluppatori che vogliano aiutare a rendere il kernel migliore; +il testo seguente potrebbe esservi d'aiuto - o essere d'aiuto ai vostri +collaboratori- per entrare a far parte della nostra comunità. + +Crediti +------- + +Questo documento è stato scritto da Jonathan Corbet, corbet@lwn.net. +È stato migliorato da Johannes Berg, James Berry, Alex Chiang, Roland +Dreier, Randy Dunlap, Jake Edge, Jiri Kosina, Matt Mackall, Arthur Marsh, +Amanda McPherson, Andrew Morton, Andrew Price, Tsugikazu Shibata e Jochen Voß. + +Questo lavoro è stato supportato dalla Linux Foundation; un ringraziamento +speciale ad Amanda McPherson, che ha visto il valore di questo lavoro e lo ha +reso possibile. + +L'importanza d'avere il codice nei sorgenti principali +------------------------------------------------------ + +Alcune aziende e sviluppatori ogni tanto si domandano perché dovrebbero +preoccuparsi di apprendere come lavorare con la comunità del kernel e di +inserire il loro codice nel ramo di sviluppo principale (per ramo principale +s'intende quello mantenuto da Linus Torvalds e usato come base dai +distributori Linux). Nel breve termine, contribuire al codice può sembrare +un costo inutile; può sembra più facile tenere separato il proprio codice e +supportare direttamente i suoi utilizzatori. La verità è che il tenere il +codice separato ("fuori dai sorgenti", *"out-of-tree"*) è un falso risparmio. + +Per dimostrare i costi di un codice "fuori dai sorgenti", eccovi +alcuni aspetti rilevanti del processo di sviluppo kernel; la maggior parte +di essi saranno approfonditi dettagliatamente più avanti in questo documento. +Considerate: + +- Il codice che è stato inserito nel ramo principale del kernel è disponibile + a tutti gli utilizzatori Linux. Sarà automaticamente presente in tutte le + distribuzioni che lo consentono. Non c'è bisogno di: driver per dischi, + scaricare file, o della scocciatura del dover supportare diverse versioni di + diverse distribuzioni; funziona già tutto, per gli sviluppatori e per gli + utilizzatori. L'inserimento nel ramo principale risolve un gran numero di + problemi di distribuzione e di supporto. + +- Nonostante gli sviluppatori kernel si sforzino di tenere stabile + l'interfaccia dello spazio utente, quella interna al kernel è in continuo + cambiamento. La mancanza di un'interfaccia interna è deliberatamente una + decisione di progettazione; ciò permette che i miglioramenti fondamentali + vengano fatti in un qualsiasi momento e che risultino fatti con un codice di + alta qualità. Ma una delle conseguenze di questa politica è che qualsiasi + codice "fuori dai sorgenti" richiede costante manutenzione per renderlo + funzionante coi kernel più recenti. Tenere un codice "fuori dai sorgenti" + richiede una mole di lavoro significativa solo per farlo funzionare. + + Invece, il codice che si trova nel ramo principale non necessita di questo + tipo di lavoro poiché ad ogni sviluppatore che faccia una modifica alle + interfacce viene richiesto di sistemare anche il codice che utilizza + quell'interfaccia. Quindi, il codice che è stato inserito nel ramo principale + ha dei costi di mantenimento significativamente più bassi. + +- Oltre a ciò, spesso il codice che è all'interno del kernel sarà migliorato da + altri sviluppatori. Dare pieni poteri alla vostra comunità di utenti e ai + clienti può portare a sorprendenti risultati che migliorano i vostri + prodotti. + +- Il codice kernel è soggetto a revisioni, sia prima che dopo l'inserimento + nel ramo principale. Non importa quanto forti fossero le abilità dello + sviluppatore originale, il processo di revisione troverà il modo di migliore + il codice. Spesso la revisione trova bachi importanti e problemi di + sicurezza. Questo è particolarmente vero per il codice che è stato + sviluppato in un ambiente chiuso; tale codice ottiene un forte beneficio + dalle revisioni provenienti da sviluppatori esteri. Il codice + "fuori dai sorgenti", invece, è un codice di bassa qualità. + +- La partecipazione al processo di sviluppo costituisce la vostra via per + influenzare la direzione di sviluppo del kernel. Gli utilizzatori che + "reclamano da bordo campo" sono ascoltati, ma gli sviluppatori attivi + hanno una voce più forte - e la capacità di implementare modifiche che + renderanno il kernel più funzionale alle loro necessità. + +- Quando il codice è gestito separatamente, esiste sempre la possibilità che + terze parti contribuiscano con una differente implementazione che fornisce + le stesse funzionalità. Se dovesse accadere, l'inserimento del codice + diventerà molto più difficile - fino all'impossibilità. Poi, dovrete far + fronte a delle alternative poco piacevoli, come: (1) mantenere un elemento + non standard "fuori dai sorgenti" per un tempo indefinito, o (2) abbandonare + il codice e far migrare i vostri utenti alla versione "nei sorgenti". + +- Contribuire al codice è l'azione fondamentale che fa funzionare tutto il + processo. Contribuendo attraverso il vostro codice potete aggiungere nuove + funzioni al kernel e fornire competenze ed esempi che saranno utili ad + altri sviluppatori. Se avete sviluppato del codice Linux (o state pensando + di farlo), avete chiaramente interesse nel far proseguire il successo di + questa piattaforma. Contribuire al codice è une delle migliori vie per + aiutarne il successo. + +Il ragionamento sopra citato si applica ad ogni codice "fuori dai sorgenti" +dal kernel, incluso il codice proprietario distribuito solamente in formato +binario. Ci sono, comunque, dei fattori aggiuntivi che dovrebbero essere +tenuti in conto prima di prendere in considerazione qualsiasi tipo di +distribuzione binaria di codice kernel. Questo include che: + +- Le questioni legali legate alla distribuzione di moduli kernel proprietari + sono molto nebbiose; parecchi detentori di copyright sul kernel credono che + molti moduli binari siano prodotti derivati del kernel e che, come risultato, + la loro diffusione sia una violazione della licenza generale di GNU (della + quale si parlerà più avanti). L'autore qui non è un avvocato, e + niente in questo documento può essere considerato come un consiglio legale. + Il vero stato legale dei moduli proprietari può essere determinato + esclusivamente da un giudice. Ma l'incertezza che perseguita quei moduli + è lì comunque. + +- I moduli binari aumentano di molto la difficoltà di fare debugging del + kernel, al punto che la maggior parte degli sviluppatori del kernel non + vorranno nemmeno tentare. Quindi la diffusione di moduli esclusivamente + binari renderà difficile ai vostri utilizzatori trovare un supporto dalla + comunità. + +- Il supporto è anche difficile per i distributori di moduli binari che devono + fornire una versione del modulo per ogni distribuzione e per ogni versione + del kernel che vogliono supportate. Per fornire una copertura ragionevole e + comprensiva, può essere richiesto di produrre dozzine di singoli moduli. + E inoltre i vostri utilizzatori dovranno aggiornare il vostro modulo + separatamente ogni volta che aggiornano il loro kernel. + +- Tutto ciò che è stato detto prima riguardo alla revisione del codice si + applica doppiamente al codice proprietario. Dato che questo codice non è + del tutto disponibile, non può essere revisionato dalla comunità e avrà, + senza dubbio, seri problemi. + +I produttori di sistemi integrati, in particolare, potrebbero esser tentati +dall'evitare molto di ciò che è stato detto in questa sezione, credendo che +stiano distribuendo un prodotto finito che utilizza una versione del kernel +immutabile e che non richiede un ulteriore sviluppo dopo il rilascio. Questa +idea non comprende il valore di una vasta revisione del codice e il valore +del permettere ai propri utenti di aggiungere funzionalità al vostro prodotto. +Ma anche questi prodotti, hanno una vita commerciale limitata, dopo la quale +deve essere rilasciata una nuova versione. A quel punto, i produttori il cui +codice è nel ramo principale di sviluppo avranno un codice ben mantenuto e +saranno in una posizione migliore per ottenere velocemente un nuovo prodotto +pronto per essere distribuito. + + +Licenza +------- + +IL codice Linux utilizza diverse licenze, ma il codice completo deve essere +compatibile con la seconda versione della licenza GNU General Public License +(GPLv2), che è la licenza che copre la distribuzione del kernel. +Nella pratica, ciò significa che tutti i contributi al codice sono coperti +anche'essi dalla GPLv2 (con, opzionalmente, una dicitura che permette la +possibilità di distribuirlo con licenze più recenti di GPL) o dalla licenza +three-clause BSD. Qualsiasi contributo che non è coperto da una licenza +compatibile non verrà accettata nel kernel. + +Per il codice sottomesso al kernel non è necessario (o richiesto) la +concessione del Copyright. Tutto il codice inserito nel ramo principale del +kernel conserva la sua proprietà originale; ne risulta che ora il kernel abbia +migliaia di proprietari. + +Una conseguenza di questa organizzazione della proprietà è che qualsiasi +tentativo di modifica della licenza del kernel è destinata ad un quasi sicuro +fallimento. Esistono alcuni scenari pratici nei quali il consenso di tutti +i detentori di copyright può essere ottenuto (o il loro codice verrà rimosso +dal kernel). Quindi, in sostanza, non esiste la possibilità che si giunga ad +una versione 3 della licenza GPL nel prossimo futuro. + +È imperativo che tutto il codice che contribuisce al kernel sia legittimamente +software libero. Per questa ragione, un codice proveniente da un contributore +anonimo (o sotto pseudonimo) non verrà accettato. È richiesto a tutti i +contributori di firmare il proprio codice, attestando così che quest'ultimo +può essere distribuito insieme al kernel sotto la licenza GPL. Il codice che +non è stato licenziato come software libero dal proprio creatore, o che +potrebbe creare problemi di copyright per il kernel (come il codice derivante +da processi di ingegneria inversa senza le opportune tutele), non può essere +diffuso. + +Domande relative a questioni legate al copyright sono frequenti nelle liste +di discussione dedicate allo sviluppo di Linux. Tali quesiti, normalmente, +non riceveranno alcuna risposta, ma una cosa deve essere tenuta presente: +le persone che risponderanno a quelle domande non sono avvocati e non possono +fornire supporti legali. Se avete questioni legali relative ai sorgenti +del codice Linux, non esiste alternativa che quella di parlare con un +avvocato esperto nel settore. Fare affidamento sulle risposte ottenute da +una lista di discussione tecnica è rischioso. diff --git a/Documentation/translations/it_IT/process/2.Process.rst b/Documentation/translations/it_IT/process/2.Process.rst new file mode 100644 index 000000000000..9af4d01617c4 --- /dev/null +++ b/Documentation/translations/it_IT/process/2.Process.rst @@ -0,0 +1,531 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/2.Process.rst <development_process>` +:Translator: Alessia Mantegazza <amantegazza@vaga.pv.it> + +.. _it_development_process: + +Come funziona il processo di sviluppo +===================================== + +Lo sviluppo del Kernel agli inizi degli anno '90 era abbastanza libero, con +un numero di utenti e sviluppatori relativamente basso. Con una base +di milioni di utenti e con 2000 sviluppatori coinvolti nel giro di un anno, +il kernel da allora ha messo in atto un certo numero di procedure per rendere +lo sviluppo più agevole. È richiesta una solida conoscenza di come tale +processo si svolge per poter esserne parte attiva. + +Il quadro d'insieme +------------------- + +Gli sviluppatori kernel utilizzano un calendario di rilascio generico, dove +ogni due o tre mesi viene effettuata un rilascio importante del kernel. +I rilasci più recenti sono stati: + + ====== ================= + 4.11 Aprile 30, 2017 + 4.12 Luglio 2, 2017 + 4.13 Settembre 3, 2017 + 4.14 Novembre 12, 2017 + 4.15 Gennaio 28, 2018 + 4.16 Aprile 1, 2018 + ====== ================= + +Ciascun rilascio 4.x è un importante rilascio del kernel con nuove +funzionalità, modifiche interne dell'API, e molto altro. Un tipico +rilascio 4.x contiene quasi 13,000 gruppi di modifiche con ulteriori +modifiche a parecchie migliaia di linee di codice. La 4.x. è pertanto la +linea di confine nello sviluppo del kernel Linux; il kernel utilizza un sistema +di sviluppo continuo che integra costantemente nuove importanti modifiche. + +Viene seguita una disciplina abbastanza lineare per l'inclusione delle +patch di ogni rilascio. All'inizio di ogni ciclo di sviluppo, la +"finestra di inclusione" viene dichiarata aperta. In quel momento il codice +ritenuto sufficientemente stabile(e che è accettato dalla comunità di sviluppo) +viene incluso nel ramo principale del kernel. La maggior parte delle +patch per un nuovo ciclo di sviluppo (e tutte le più importanti modifiche) +saranno inserite durante questo periodo, ad un ritmo che si attesta sulle +1000 modifiche ("patch" o "gruppo di modifiche") al giorno. + +(per inciso, vale la pena notare che i cambiamenti integrati durante la +"finestra di inclusione" non escono dal nulla; questi infatti, sono stati +raccolti e, verificati in anticipo. Il funzionamento di tale procedimento +verrà descritto dettagliatamente più avanti). + +La finestra di inclusione resta attiva approssimativamente per due settimane. +Al termine di questo periodo, Linus Torvald dichiarerà che la finestra è +chiusa e rilascerà il primo degli "rc" del kernel. +Per il kernel che è destinato ad essere 2.6.40, per esempio, il rilascio +che emerge al termine della finestra d'inclusione si chiamerà 2.6.40-rc1. +Questo rilascio indica che il momento di aggiungere nuovi componenti è +passato, e che è iniziato il periodo di stabilizzazione del prossimo kernel. + +Nelle successive sei/dieci settimane, potranno essere sottoposte solo modifiche +che vanno a risolvere delle problematiche. Occasionalmente potrà essere +consentita una modifica più consistente, ma tali occasioni sono rare. +Gli sviluppatori che tenteranno di aggiungere nuovi elementi al di fuori della +finestra di inclusione, tendenzialmente, riceveranno un accoglienza poco +amichevole. Come regola generale: se vi perdete la finestra di inclusione per +un dato componente, la cosa migliore da fare è aspettare il ciclo di sviluppo +successivo (un'eccezione può essere fatta per i driver per hardware non +supportati in precedenza; se toccano codice non facente parte di quello +attuale, che non causino regressioni e che potrebbero essere aggiunti in +sicurezza in un qualsiasi momento) + +Mentre le correzioni si aprono la loro strada all'interno del ramo principale, +il ritmo delle modifiche rallenta col tempo. Linus rilascia un nuovo +kernel -rc circa una volta alla settimana; e ne usciranno circa 6 o 9 prima +che il kernel venga considerato sufficientemente stabile e che il rilascio +finale 2.6.x venga fatto. A quel punto tutto il processo ricomincerà. + +Esempio: ecco com'è andato il ciclo di sviluppo della versione 4.16 +(tutte le date si collocano nel 2018) + + + ============== ======================================= + Gennaio 28 4.15 rilascio stabile + Febbraio 11 4.16-rc1, finestra di inclusione chiusa + Febbraio 18 4.16-rc2 + Febbraio 25 4.16-rc3 + Marzo 4 4.16-rc4 + Marzo 11 4.16-rc5 + Marzo 18 4.16-rc6 + Marzo 25 4.16-rc7 + Aprile 1 4.17 rilascio stabile + ============== ======================================= + +In che modo gli sviluppatori decidono quando chiudere il ciclo di sviluppo e +creare quindi una rilascio stabile? Un metro valido è il numero di regressioni +rilevate nel precedente rilascio. Nessun baco è il benvenuto, ma quelli che +procurano problemi su sistemi che hanno funzionato in passato sono considerati +particolarmente seri. Per questa ragione, le modifiche che portano ad una +regressione sono viste sfavorevolmente e verranno quasi sicuramente annullate +durante il periodo di stabilizzazione. + +L'obiettivo degli sviluppatori è quello di aggiustare tutte le regressioni +conosciute prima che avvenga il rilascio stabile. Nel mondo reale, questo +tipo di perfezione difficilmente viene raggiunta; esistono troppe variabili +in un progetto di questa portata. Arriva un punto dove ritardare il rilascio +finale peggiora la situazione; la quantità di modifiche in attesa della +prossima finestra di inclusione crescerà enormemente, creando ancor più +regressioni al giro successivo. Quindi molti kernel 4.x escono con una +manciata di regressioni delle quali, si spera, nessuna è grave. + +Una volta che un rilascio stabile è fatto, il suo costante mantenimento è +affidato al "squadra stabilità", attualmente composta da Greg Kroah-Hartman. +Questa squadra rilascia occasionalmente degli aggiornamenti relativi al +rilascio stabile usando la numerazione 4.x.y. Per essere presa in +considerazione per un rilascio d'aggiornamento, una modifica deve: +(1) correggere un baco importante (2) essere già inserita nel ramo principale +per il prossimo sviluppo del kernel. Solitamente, passato il loro rilascio +iniziale, i kernel ricevono aggiornamenti per più di un ciclo di sviluppo. +Quindi, per esempio, la storia del kernel 4.13 appare così: + + ============== =============================== + Settembre 3 4.13 rilascio stabile + Settembre 13 4.13.1 + Settembre 20 4.13.2 + Settembre 27 4.13.3 + Ottobre 5 4.13.4 + Ottobre 12 4.13.5 + ... ... + Novembre 24 4.13.16 + ============== =============================== + +La 4.13.16 fu l'aggiornamento finale per la versione 4.13. + +Alcuni kernel sono destinati ad essere kernel a "lungo termine"; questi +riceveranno assistenza per un lungo periodo di tempo. Al momento in cui +scriviamo, i manutentori dei kernel stabili a lungo termine sono: + + ====== ====================== ========================================== + 3.16 Ben Hutchings (kernel stabile molto più a lungo termine) + 4.1 Sasha Levin + 4.4 Greg Kroah-Hartman (kernel stabile molto più a lungo termine) + 4.9 Greg Kroah-Hartman + 4.14 Greg Kroah-Hartman + ====== ====================== ========================================== + + +Questa selezione di kernel di lungo periodo sono puramente dovuti ai loro +manutentori, alla loro necessità e al tempo per tenere aggiornate proprio +quelle versioni. Non ci sono altri kernel a lungo termine in programma per +alcun rilascio in arrivo. + +Il ciclo di vita di una patch +----------------------------- + +Le patch non passano direttamente dalla tastiera dello sviluppatori +al ramo principale del kernel. Esiste, invece, una procedura disegnata +per assicurare che ogni patch sia di buona qualità e desiderata nel +ramo principale. Questo processo avviene velocemente per le correzioni +meno importanti, o, nel caso di patch ampie e controverse, va avanti per anni. +Per uno sviluppatore la maggior frustrazione viene dalla mancanza di +comprensione di questo processo o dai tentativi di aggirarlo. + +Nella speranza di ridurre questa frustrazione, questo documento spiegherà +come una patch viene inserita nel kernel. Ciò che segue è un'introduzione +che descrive il processo ideale. Approfondimenti verranno invece trattati +più avanti. + +Una patch attraversa, generalmente, le seguenti fasi: + + - Progetto. In questa fase sono stabilite quelli che sono i requisiti + della modifica - e come verranno soddisfatti. Il lavoro di progettazione + viene spesso svolto senza coinvolgere la comunità, ma è meglio renderlo + il più aperto possibile; questo può far risparmiare molto tempo evitando + eventuali riprogettazioni successive. + + - Prima revisione. Le patch vengono pubblicate sulle liste di discussione + interessate, e gli sviluppatori in quella lista risponderanno coi loro + commenti. Se si svolge correttamente, questo procedimento potrebbe far + emergere problemi rilevanti in una patch. + + - Revisione più ampia. Quando la patch è quasi pronta per essere inserita + nel ramo principale, un manutentore importante del sottosistema dovrebbe + accettarla - anche se, questa accettazione non è una garanzia che la + patch arriverà nel ramo principale. La patch sarà visibile nei sorgenti + del sottosistema in questione e nei sorgenti -next (descritti sotto). + Quando il processo va a buon fine, questo passo porta ad una revisione + più estesa della patch e alla scoperta di problemi d'integrazione + con il lavoro altrui. + +- Per favore, tenete da conto che la maggior parte dei manutentori ha + anche un lavoro quotidiano, quindi integrare le vostre patch potrebbe + non essere la loro priorità più alta. Se una vostra patch riceve + dei suggerimenti su dei cambiamenti necessari, dovreste applicare + quei cambiamenti o giustificare perché non sono necessari. Se la vostra + patch non riceve alcuna critica ma non è stata integrata dal + manutentore del driver o sottosistema, allora dovreste continuare con + i necessari aggiornamenti per mantenere la patch aggiornata al kernel + più recente cosicché questa possa integrarsi senza problemi; continuate + ad inviare gli aggiornamenti per essere revisionati e integrati. + + - Inclusione nel ramo principale. Eventualmente, una buona patch verrà + inserita all'interno nel repositorio principale, gestito da + Linus Torvalds. In questa fase potrebbero emergere nuovi problemi e/o + commenti; è importante che lo sviluppatore sia collaborativo e che sistemi + ogni questione che possa emergere. + + - Rilascio stabile. Ora, il numero di utilizzatori che sono potenzialmente + toccati dalla patch è aumentato, quindi, ancora una volta, potrebbero + emergere nuovi problemi. + + - Manutenzione di lungo periodo. Nonostante sia possibile che uno sviluppatore + si dimentichi del codice dopo la sua integrazione, questo comportamento + lascia una brutta impressione nella comunità di sviluppo. Integrare il + codice elimina alcuni degli oneri facenti parte della manutenzione, in + particolare, sistemerà le problematiche causate dalle modifiche all'API. + Ma lo sviluppatore originario dovrebbe continuare ad assumersi la + responsabilità per il codice se quest'ultimo continua ad essere utile + nel lungo periodo. + +Uno dei più grandi errori fatti dagli sviluppatori kernel (o dai loro datori +di lavoro) è quello di cercare di ridurre tutta la procedura ad una singola +"integrazione nel remo principale". Questo approccio inevitabilmente conduce +a una condizione di frustrazione per tutti coloro che sono coinvolti. + +Come le modifiche finiscono nel Kernel +-------------------------------------- + +Esiste una sola persona che può inserire le patch nel repositorio principale +del kernel: Linus Torvalds. Ma, di tutte le 9500 patch che entrarono nella +versione 2.6.38 del kernel, solo 112 (circa l'1,3%) furono scelte direttamente +da Linus in persona. Il progetto del kernel è cresciuto fino a raggiungere +una dimensione tale per cui un singolo sviluppatore non può controllare e +selezionare indipendentemente ogni modifica senza essere supportato. +La via scelta dagli sviluppatori per indirizzare tale crescita è stata quella +di utilizzare un sistema di "sottotenenti" basato sulla fiducia. + +Il codice base del kernel è spezzato in una serie si sottosistemi: rete, +supporto per specifiche architetture, gestione della memoria, video e +strumenti, etc. Molti sottosistemi hanno un manutentore designato: ovvero uno +sviluppatore che ha piena responsabilità di tutto il codice presente in quel +sottosistema. Tali manutentori di sottosistema sono i guardiani +(in un certo senso) della parte di kernel che gestiscono; sono coloro che +(solitamente) accetteranno una patch per l'inclusione nel ramo principale +del kernel. + +I manutentori di sottosistema gestiscono ciascuno la propria parte dei sorgenti +del kernel, utilizzando abitualmente (ma certamente non sempre) git. +Strumenti come git (e affini come quilt o mercurial) permettono ai manutentori +di stilare una lista delle patch, includendo informazioni sull'autore ed +altri metadati. In ogni momento, il manutentore può individuare quale patch +nel sua repositorio non si trova nel ramo principale. + +Quando la "finestra di integrazione" si apre, i manutentori di alto livello +chiederanno a Linus di "prendere" dai loro repositori le modifiche che hanno +selezionato per l'inclusione. Se Linus acconsente, il flusso di patch si +convoglierà nel repositorio di quest ultimo, divenendo così parte del ramo +principale del kernel. La quantità d'attenzione che Linus presta alle +singole patch ricevute durante l'operazione di integrazione varia. +È chiaro che, qualche volta, guardi più attentamente. Ma, come regola +generale, Linus confida nel fatto che i manutentori di sottosistema non +selezionino pessime patch. + +I manutentori di sottosistemi, a turno, possono "prendere" patch +provenienti da altri manutentori. Per esempio, i sorgenti per la rete rete +sono costruiti da modifiche che si sono accumulate inizialmente nei sorgenti +dedicati ai driver per dispositivi di rete, rete senza fili, ecc. Tale +catena di repositori può essere più o meno lunga, benché raramente ecceda +i due o tre collegamenti. Questo processo è conosciuto come +"la catena della fiducia", perché ogni manutentore all'interno della +catena si fida di coloro che gestiscono i livelli più bassi. + +Chiaramente, in un sistema come questo, l'inserimento delle patch all'interno +del kernel si basa sul trovare il manutentore giusto. Di norma, inviare +patch direttamente a Linus non è la via giusta. + + +Sorgenti -next +-------------- + +La catena di sottosistemi guida il flusso di patch all'interno del kernel, +ma solleva anche un interessante quesito: se qualcuno volesse vedere tutte le +patch pronte per la prossima finestra di integrazione? +Gli sviluppatori si interesseranno alle patch in sospeso per verificare +che non ci siano altri conflitti di cui preoccuparsi; una modifica che, per +esempio, cambia il prototipo di una funzione fondamentale del kernel andrà in +conflitto con qualsiasi altra modifica che utilizzi la vecchia versione di +quella funzione. Revisori e tester vogliono invece avere accesso alle +modifiche nella loro totalità prima che approdino nel ramo principale del +kernel. Uno potrebbe prendere le patch provenienti da tutti i sottosistemi +d'interesse, ma questo sarebbe un lavoro enorme e fallace. + +La risposta ci viene sotto forma di sorgenti -next, dove i sottosistemi sono +raccolti per essere testati e controllati. Il più vecchio di questi sorgenti, +gestito da Andrew Morton, è chiamato "-mm" (memory management, che è l'inizio +di tutto). L'-mm integra patch proveniente da una lunga lista di sottosistemi; +e ha, inoltre, alcune patch destinate al supporto del debugging. + +Oltre a questo, -mm contiene una raccolta significativa di patch che sono +state selezionate da Andrew direttamente. Queste patch potrebbero essere +state inviate in una lista di discussione, o possono essere applicate ad una +parte del kernel per la quale non esiste un sottosistema dedicato. +Di conseguenza, -mm opera come una specie di sottosistema "ultima spiaggia"; +se per una patch non esiste una via chiara per entrare nel ramo principale, +allora è probabile che finirà in -mm. Le patch passate per -mm +eventualmente finiranno nel sottosistema più appropriato o saranno inviate +direttamente a Linus. In un tipico ciclo di sviluppo, circa il 5-10% delle +patch andrà nel ramo principale attraverso -mm. + +La patch -mm correnti sono disponibili nella cartella "mmotm" (-mm of +the moment) all'indirizzo: + + http://www.ozlabs.org/~akpm/mmotm/ + +È molto probabile che l'uso dei sorgenti MMOTM diventi un'esperienza +frustrante; ci sono buone probabilità che non compili nemmeno. + +I sorgenti principali per il prossimo ciclo d'integrazione delle patch +è linux-next, gestito da Stephen Rothwell. I sorgenti linux-next sono, per +definizione, un'istantanea di come dovrà apparire il ramo principale dopo che +la prossima finestra di inclusione si chiuderà. I linux-next sono annunciati +sulla lista di discussione linux-kernel e linux-next nel momento in cui +vengono assemblati; e possono essere scaricate da: + + http://www.kernel.org/pub/linux/kernel/next/ + +Linux-next è divenuto parte integrante del processo di sviluppo del kernel; +tutte le patch incorporate durante una finestra di integrazione dovrebbero +aver trovato la propria strada in linux-next, a volte anche prima dell'apertura +della finestra di integrazione. + + +Sorgenti in preparazione +------------------------ + +Nei sorgenti del kernel esiste la cartella drivers/staging/, dove risiedono +molte sotto-cartelle per i driver o i filesystem che stanno per essere aggiunti +al kernel. Questi restano nella cartella drivers/staging fintanto che avranno +bisogno di maggior lavoro; una volta completato, possono essere spostate +all'interno del kernel nel posto più appropriato. Questo è il modo di tener +traccia dei driver che non sono ancora in linea con gli standard di codifica +o qualità, ma che le persone potrebbero voler usare ugualmente e tracciarne +lo sviluppo. + +Greg Kroah-Hartman attualmente gestisce i sorgenti in preparazione. I driver +che non sono completamente pronti vengono inviati a lui, e ciascun driver avrà +la propria sotto-cartella in drivers/staging/. Assieme ai file sorgenti +dei driver, dovrebbe essere presente nella stessa cartella anche un file TODO. +Il file TODO elenca il lavoro ancora da fare su questi driver per poter essere +accettati nel kernel, e indica anche la lista di persone da inserire in copia +conoscenza per ogni modifica fatta. Le regole attuali richiedono che i +driver debbano, come minimo, compilare adeguatamente. + +La *preparazione* può essere una via relativamente facile per inserire nuovi +driver all'interno del ramo principale, dove, con un po' di fortuna, saranno +notati da altri sviluppatori e migliorati velocemente. Entrare nella fase +di preparazione non è però la fine della storia, infatti, il codice che si +trova nella cartella staging che non mostra regolari progressi potrebbe +essere rimosso. Le distribuzioni, inoltre, tendono a dimostrarsi relativamente +riluttanti nell'attivare driver in preparazione. Quindi lo preparazione è, +nel migliore dei casi, una tappa sulla strada verso il divenire un driver +del ramo principale. + + +Strumenti +--------- + +Come è possibile notare dal testo sopra, il processo di sviluppo del kernel +dipende pesantemente dalla capacità di guidare la raccolta di patch in +diverse direzioni. L'intera cosa non funzionerebbe se non venisse svolta +con l'uso di strumenti appropriati e potenti. Spiegare l'uso di tali +strumenti non è lo scopo di questo documento, ma c'è spazio per alcuni +consigli. + +In assoluto, nella comunità del kernel, predomina l'uso di git come sistema +di gestione dei sorgenti. Git è una delle diverse tipologie di sistemi +distribuiti di controllo versione che sono stati sviluppati nella comunità +del software libero. Esso è calibrato per lo sviluppo del kernel, e si +comporta abbastanza bene quando ha a che fare con repositori grandi e con un +vasto numero di patch. Git ha inoltre la reputazione di essere difficile +da imparare e utilizzare, benché stia migliorando. Agli sviluppatori +del kernel viene richiesta un po' di familiarità con git; anche se non lo +utilizzano per il proprio lavoro, hanno bisogno di git per tenersi al passo +con il lavoro degli altri sviluppatori (e con il ramo principale). + +Git è ora compreso in quasi tutte le distribuzioni Linux. Esiste una sito che +potete consultare: + + http://git-scm.com/ + +Qui troverete i riferimenti alla documentazione e alle guide passo-passo. + +Tra gli sviluppatori Kernel che non usano git, la scelta alternativa più +popolare è quasi sicuramente Mercurial: + + http://www.selenic.com/mercurial/ + +Mercurial condivide diverse caratteristiche con git, ma fornisce +un'interfaccia che potrebbe risultare più semplice da utilizzare. + +L'altro strumento che vale la pena conoscere è Quilt: + + http://savannah.nongnu.org/projects/quilt/ + + +Quilt è un sistema di gestione delle patch, piuttosto che un sistema +di gestione dei sorgenti. Non mantiene uno storico degli eventi; ma piuttosto +è orientato verso il tracciamento di uno specifico insieme di modifiche +rispetto ad un codice in evoluzione. Molti dei più grandi manutentori di +sottosistema utilizzano quilt per gestire le patch che dovrebbero essere +integrate. Per la gestione di certe tipologie di sorgenti (-mm, per esempio), +quilt è il miglior strumento per svolgere il lavoro. + + +Liste di discussione +-------------------- + +Una grossa parte del lavoro di sviluppo del Kernel Linux viene svolto tramite +le liste di discussione. È difficile essere un membro della comunità +pienamente coinvolto se non si partecipa almeno ad una lista da qualche +parte. Ma, le liste di discussione di Linux rappresentano un potenziale +problema per gli sviluppatori, che rischiano di venir sepolti da un mare di +email, restare incagliati nelle convenzioni in vigore nelle liste Linux, +o entrambi. + +Molte delle liste di discussione del Kernel girano su vger.kernel.org; +l'elenco principale lo si trova sul sito: + + http://vger.kernel.org/vger-lists.html + +Esistono liste gestite altrove; un certo numero di queste sono in +lists.redhat.com. + +La lista di discussione principale per lo sviluppo del kernel è, ovviamente, +linux-kernel. Questa lista è un luogo ostile dove trovarsi; i volumi possono +raggiungere i 500 messaggi al giorno, la quantità di "rumore" è elevata, +la conversazione può essere strettamente tecnica e i partecipanti non sono +sempre preoccupati di mostrare un alto livello di educazione. Ma non esiste +altro luogo dove la comunità di sviluppo del kernel si unisce per intero; +gli sviluppatori che evitano tale lista si perderanno informazioni importanti. + +Ci sono alcuni consigli che possono essere utili per sopravvivere a +linux-kernel: + +- Tenete la lista in una cartella separata, piuttosto che inserirla nella + casella di posta principale. Così da essere in grado di ignorare il flusso + di mail per un certo periodo di tempo. + +- Non cercate di seguire ogni conversazione - nessuno lo fa. È importante + filtrare solo gli argomenti d'interesse (sebbene va notato che le + conversazioni di lungo periodo possono deviare dall'argomento originario + senza cambiare il titolo della mail) e le persone che stanno partecipando. + +- Non alimentate i troll. Se qualcuno cerca di creare nervosismo, ignoratelo. + +- Quando rispondete ad una mail linux-kernel (o ad altre liste) mantenete + tutti i Cc:. In assenza di importanti motivazioni (come una richiesta + esplicita), non dovreste mai togliere destinatari. Assicuratevi sempre che + la persona alla quale state rispondendo sia presente nella lista Cc. Questa + usanza fa si che divenga inutile chiedere esplicitamente di essere inseriti + in copia nel rispondere al vostro messaggio. + +- Cercate nell'archivio della lista (e nella rete nella sua totalità) prima + di far domande. Molti sviluppatori possono divenire impazienti con le + persone che chiaramente non hanno svolto i propri compiti a casa. + +- Evitate il *top-posting* (cioè la pratica di mettere la vostra risposta sopra + alla frase alla quale state rispondendo). Ciò renderebbe la vostra risposta + difficile da leggere e genera scarsa impressione. + +- Chiedete nella lista di discussione corretta. Linux-kernel può essere un + punto di incontro generale, ma non è il miglior posto dove trovare + sviluppatori da tutti i sottosistemi. + +Infine, la ricerca della corretta lista di discussione è uno degli errori più +comuni per gli sviluppatori principianti. Qualcuno che pone una domanda +relativa alla rete su linux-kernel riceverà quasi certamente il suggerimento +di chiedere sulla lista netdev, che è la lista frequentata dagli sviluppatori +di rete. Ci sono poi altre liste per i sottosistemi SCSI, video4linux, IDE, +filesystem, etc. Il miglior posto dove cercare una lista di discussione è il +file MAINTAINERS che si trova nei sorgenti del kernel. + +Iniziare con lo sviluppo del Kernel +----------------------------------- + +Sono comuni le domande sul come iniziare con lo sviluppo del kernel - sia da +singole persone che da aziende. Altrettanto comuni sono i passi falsi che +rendono l'inizio di tale relazione più difficile di quello che dovrebbe essere. + +Le aziende spesso cercano di assumere sviluppatori noti per creare un gruppo +di sviluppo iniziale. Questo, in effetti, può essere una tecnica efficace. +Ma risulta anche essere dispendiosa e non va ad accrescere il bacino di +sviluppatori kernel con esperienza. È possibile anche "portare a casa" +sviluppatori per accelerare lo sviluppo del kernel, dando comunque +all'investimento un po' di tempo. Prendersi questo tempo può fornire +al datore di lavoro un gruppo di sviluppatori che comprendono sia il kernel +che l'azienda stessa, e che possono supportare la formazione di altre persone. +Nel medio periodo, questa è spesso uno delle soluzioni più proficue. + +I singoli sviluppatori sono spesso, comprensibilmente, una perdita come punto +di partenza. Iniziare con un grande progetto può rivelarsi intimidatorio; +spesso all'inizio si vuole solo verificare il terreno con qualcosa di piccolo. +Questa è una delle motivazioni per le quali molti sviluppatori saltano alla +creazione di patch che vanno a sistemare errori di battitura o +problematiche minori legate allo stile del codice. Sfortunatamente, tali +patch creano un certo livello di rumore che distrae l'intera comunità di +sviluppo, quindi, sempre di più, esse vengono degradate. I nuovi sviluppatori +che desiderano presentarsi alla comunità non riceveranno l'accoglienza +che vorrebbero con questi mezzi. + +Andrew Morton da questo consiglio agli aspiranti sviluppatori kernel + +:: + + Il primo progetto per un neofita del kernel dovrebbe essere + sicuramente quello di "assicurarsi che il kernel funzioni alla + perfezione sempre e su tutte le macchine sulle quali potete stendere + la vostra mano". Solitamente il modo per fare ciò è quello di + collaborare con gli altri nel sistemare le cose (questo richiede + persistenza!) ma va bene - è parte dello sviluppo kernel. + +(http://lwn.net/Articles/283982/). + +In assenza di problemi ovvi da risolvere, si consiglia agli sviluppatori +di consultare, in generale, la lista di regressioni e di bachi aperti. +Non c'è mai carenza di problematiche bisognose di essere sistemate; +accollandosi tali questioni gli sviluppatori accumuleranno esperienza con +la procedura, ed allo stesso tempo, aumenteranno la loro rispettabilità +all'interno della comunità di sviluppo. diff --git a/Documentation/translations/it_IT/process/3.Early-stage.rst b/Documentation/translations/it_IT/process/3.Early-stage.rst new file mode 100644 index 000000000000..443ac1e5558f --- /dev/null +++ b/Documentation/translations/it_IT/process/3.Early-stage.rst @@ -0,0 +1,241 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/3.Early-stage.rst <development_early_stage>` +:Translator: Alessia Mantegazza <amantegazza@vaga.pv.it> + +.. _it_development_early_stage: + +I primi passi della pianificazione +================================== + +Osservando un progetto di sviluppo per il kernel Linux, si potrebbe essere +tentati dal saltare tutto e iniziare a codificare. Tuttavia, come ogni +progetto significativo, molta della preparazione per giungere al successo +viene fatta prima che una sola linea di codice venga scritta. Il tempo speso +nella pianificazione e la comunicazione può far risparmiare molto +tempo in futuro. + +Specificare il problema +----------------------- + +Come qualsiasi progetto ingegneristico, un miglioramento del kernel di +successo parte con una chiara descrizione del problema da risolvere. +In alcuni casi, questo passaggio è facile: ad esempio quando un driver è +richiesto per un particolare dispositivo. In altri casi invece, si +tende a confondere il problema reale con le soluzioni proposte e questo +può portare all'emergere di problemi. + +Facciamo un esempio: qualche anno fa, gli sviluppatori che lavoravano con +linux audio cercarono un modo per far girare le applicazioni senza dropouts +o altri artefatti dovuti all'eccessivo ritardo nel sistema. La soluzione +alla quale giunsero fu un modulo del kernel destinato ad agganciarsi al +framework Linux Security Module (LSM); questo modulo poteva essere +configurato per dare ad una specifica applicazione accesso allo +schedulatore *realtime*. Tale modulo fu implementato e inviato nella +lista di discussione linux-kernel, dove incontrò subito dei problemi. + +Per gli sviluppatori audio, questo modulo di sicurezza era sufficiente a +risolvere il loro problema nell'immediato. Per l'intera comunità kernel, +invece, era un uso improprio del framework LSM (che non è progettato per +conferire privilegi a processi che altrimenti non avrebbero potuto ottenerli) +e un rischio per la stabilità del sistema. Le loro soluzioni di punta nel +breve periodo, comportavano un accesso alla schedulazione realtime attraverso +il meccanismo rlimit, e nel lungo periodo un costante lavoro nella riduzione +dei ritardi. + +La comunità audio, comunque, non poteva vedere al di là della singola +soluzione che avevano implementato; erano riluttanti ad accettare alternative. +Il conseguente dissenso lasciò in quegli sviluppatori un senso di +disillusione nei confronti dell'intero processo di sviluppo; uno di loro +scrisse questo messaggio: + + Ci sono numerosi sviluppatori del kernel Linux davvero bravi, ma + rischiano di restare sovrastati da una vasta massa di stolti arroganti. + Cercare di comunicare le richieste degli utenti a queste persone è + una perdita di tempo. Loro sono troppo "intelligenti" per stare ad + ascoltare dei poveri mortali. + + (http://lwn.net/Articles/131776/). + +La realtà delle cose fu differente; gli sviluppatori del kernel erano molto +più preoccupati per la stabilità del sistema, per la manutenzione di lungo +periodo e cercavano la giusta soluzione alla problematica esistente con uno +specifico modulo. La morale della storia è quella di concentrarsi sul +problema - non su di una specifica soluzione- e di discuterne con la comunità +di sviluppo prima di investire tempo nella scrittura del codice. + +Quindi, osservando un progetto di sviluppo del kernel, si dovrebbe +rispondere a questa lista di domande: + +- Qual'è, precisamente, il problema che dev'essere risolto? + +- Chi sono gli utenti coinvolti da tal problema? A quale caso dovrebbe + essere indirizzata la soluzione? + +- In che modo il kernel risulta manchevole nell'indirizzare il problema + in questione? + +Solo dopo ha senso iniziare a considerare le possibili soluzioni. + +Prime discussioni +----------------- + +Quando si pianifica un progetto di sviluppo per il kernel, sarebbe quanto meno +opportuno discuterne inizialmente con la comunità prima di lanciarsi +nell'implementazione. Una discussione preliminare può far risparmiare sia +tempo che problemi in svariati modi: + + - Potrebbe essere che il problema sia già stato risolto nel kernel in + una maniera che non avete ancora compreso. Il kernel Linux è grande e ha + una serie di funzionalità e capacità che non sono scontate nell'immediato. + Non tutte le capacità del kernel sono documentate così bene come ci + piacerebbe, ed è facile perdersi qualcosa. Il vostro autore ha assistito + alla pubblicazione di un driver intero che duplica un altro driver + esistente di cui il nuovo autore era ignaro. Il codice che rinnova + ingranaggi già esistenti non è soltanto dispendioso; non verrà nemmeno + accettato nel ramo principale del kernel. + + - Potrebbero esserci proposte che non sono considerate accettabili per + l'integrazione all'interno del ramo principale. È meglio affrontarle + prima di scrivere il codice. + + - È possibile che altri sviluppatori abbiano pensato al problema; potrebbero + avere delle idee per soluzioni migliori, e potrebbero voler contribuire + alla loro creazione. + +Anni di esperienza con la comunità di sviluppo del kernel hanno impartito una +chiara lezione: il codice per il kernel che è pensato e sviluppato a porte +chiuse, inevitabilmente, ha problematiche che si rivelano solo quando il +codice viene rilasciato pubblicamente. Qualche volta tali problemi sono +importanti e richiedono mesi o anni di sforzi prima che il codice possa +raggiungere gli standard richiesti della comunità. +Alcuni esempi possono essere: + + - La rete Devicescape è stata creata e implementata per sistemi + mono-processore. Non avrebbe potuto essere inserita nel ramo principale + fino a che non avesse supportato anche i sistemi multi-processore. + Riadattare i meccanismi di sincronizzazione e simili è un compito difficile; + come risultato, l'inserimento di questo codice (ora chiamato mac80211) + fu rimandato per più di un anno. + + - Il filesystem Reiser4 include una seria di funzionalità che, secondo + l'opinione degli sviluppatori principali del kernel, avrebbero dovuto + essere implementate a livello di filesystem virtuale. Comprende + anche funzionalità che non sono facilmente implementabili senza esporre + il sistema al rischio di uno stallo. La scoperta tardiva di questi + problemi - e il diniego a risolverne alcuni - ha avuto come conseguenza + il fatto che Raiser4 resta fuori dal ramo principale del kernel. + + - Il modulo di sicurezza AppArmor utilizzava strutture dati del + filesystem virtuale interno in modi che sono stati considerati rischiosi e + inattendibili. Questi problemi (tra le altre cose) hanno tenuto AppArmor + fuori dal ramo principale per anni. + +Ciascuno di questi casi è stato un travaglio e ha richiesto del lavoro +straordinario, cose che avrebbero potuto essere evitate con alcune +"chiacchierate" preliminari con gli sviluppatori kernel. + +Con chi parlare? +---------------- + +Quando gli sviluppatori hanno deciso di rendere pubblici i propri progetti, la +domanda successiva sarà: da dove partiamo? La risposta è quella di trovare +la giusta lista di discussione e il giusto manutentore. Per le liste di +discussione, il miglior approccio è quello di cercare la lista più adatta +nel file MAINTAINERS. Se esiste una lista di discussione di sottosistema, +è preferibile pubblicare lì piuttosto che sulla lista di discussione generale +del kernel Linux; avrete maggiori probabilità di trovare sviluppatori con +esperienza sul tema, e l'ambiente che troverete potrebbe essere più +incoraggiante. + +Trovare manutentori può rivelarsi un po' difficoltoso. Ancora, il file +MAINTAINERS è il posto giusto da dove iniziare. Il file potrebbe non essere +sempre aggiornato, inoltre, non tutti i sottosistemi sono rappresentati qui. +Coloro che sono elencati nel file MAINTAINERS potrebbero, in effetti, non +essere le persone che attualmente svolgono quel determinato ruolo. Quindi, +quando c'è un dubbio su chi contattare, un trucco utile è quello di usare +git (git log in particolare) per vedere chi attualmente è attivo all'interno +del sottosistema interessato. Controllate chi sta scrivendo le patch, +e chi, se non ci fosse nessuno, sta aggiungendo la propria firma +(Signed-off-by) a quelle patch. Quelle sono le persone maggiormente +qualificate per aiutarvi con lo sviluppo di nuovo progetto. + +Il compito di trovare il giusto manutentore, a volte, è una tale sfida che +ha spinto gli sviluppatori del kernel a scrivere uno script che li aiutasse +in questa ricerca: + +:: + + .../scripts/get_maintainer.pl + +Se questo script viene eseguito con l'opzione "-f" ritornerà il +manutentore(i) attuale per un dato file o cartella. Se viene passata una +patch sulla linea di comando, lo script elencherà i manutentori che +dovrebbero riceverne una copia. Ci sono svariate opzioni che regolano +quanto a fondo get_maintainer.pl debba cercare i manutentori; +siate quindi prudenti nell'utilizzare le opzioni più aggressive poiché +potreste finire per includere sviluppatori che non hanno un vero interesse +per il codice che state modificando. + +Se tutto ciò dovesse fallire, parlare con Andrew Morton potrebbe essere +un modo efficace per capire chi è il manutentore di un dato pezzo di codice. + +Quando pubblicare +----------------- + +Se potete, pubblicate i vostri intenti durante le fasi preliminari, sarà +molto utile. Descrivete il problema da risolvere e ogni piano che è stato +elaborato per l'implementazione. Ogni informazione fornita può aiutare +la comunità di sviluppo a fornire spunti utili per il progetto. + +Un evento che potrebbe risultare scoraggiate e che potrebbe accadere in +questa fase non è il ricevere una risposta ostile, ma, invece, ottenere +una misera o inesistente reazione. La triste verità è che: (1) gli +sviluppatori del kernel tendono ad essere occupati, (2) ci sono tante persone +con grandi progetti e poco codice (o anche solo la prospettiva di +avere un codice) a cui riferirsi e (3) nessuno è obbligato a revisionare +o a fare osservazioni in merito ad idee pubblicate da altri. Oltre a +questo, progetti di alto livello spesso nascondono problematiche che si +rivelano solo quando qualcuno cerca di implementarle; per questa ragione +gli sviluppatori kernel preferirebbero vedere il codice. + +Quindi, se una richiesta pubblica di commenti riscuote poco successo, non +pensate che ciò significhi che non ci sia interesse nel progetto. +Sfortunatamente, non potete nemmeno assumere che non ci siano problemi con +la vostra idea. La cosa migliore da fare in questa situazione è quella di +andare avanti e tenere la comunità informata mentre procedete. + +Ottenere riscontri ufficiali +---------------------------- + +Se il vostro lavoro è stato svolto in un ambiente aziendale - come molto +del lavoro fatto su Linux - dovete, ovviamente, avere il permesso dei +dirigenti prima che possiate pubblicare i progetti, o il codice aziendale, +su una lista di discussione pubblica. La pubblicazione di codice che non +è stato rilascio espressamente con licenza GPL-compatibile può rivelarsi +problematico; prima la dirigenza, e il personale legale, troverà una decisione +sulla pubblicazione di un progetto, meglio sarà per tutte le persone coinvolte. + +A questo punto, alcuni lettori potrebbero pensare che il loro lavoro sul +kernel è preposto a supportare un prodotto che non è ancora ufficialmente +riconosciuto. Rivelare le intenzioni dei propri datori di lavori in una +lista di discussione pubblica potrebbe non essere una soluzione valida. +In questi casi, vale la pena considerare se la segretezza sia necessaria +o meno; spesso non c'è una reale necessità di mantenere chiusi i progetti di +sviluppo. + +Detto ciò, ci sono anche casi dove l'azienda legittimamente non può rivelare +le proprie intenzioni in anticipo durante il processo di sviluppo. Le aziende +che hanno sviluppatori kernel esperti possono scegliere di procedere a +carte coperte partendo dall'assunto che saranno in grado di evitare, o gestire, +in futuro, eventuali problemi d'integrazione. Per le aziende senza questo tipo +di esperti, la migliore opzione è spesso quella di assumere uno sviluppatore +esterno che revisioni i progetti con un accordo di segretezza. +La Linux Foundation applica un programma di NDA creato appositamente per +aiutare le aziende in questa particolare situazione; potrete trovare più +informazioni sul sito: + + http://www.linuxfoundation.org/en/NDA_program + +Questa tipologia di revisione è spesso sufficiente per evitare gravi problemi +senza che sia richiesta l'esposizione pubblica del progetto. diff --git a/Documentation/translations/it_IT/process/4.Coding.rst b/Documentation/translations/it_IT/process/4.Coding.rst new file mode 100644 index 000000000000..c61059015e52 --- /dev/null +++ b/Documentation/translations/it_IT/process/4.Coding.rst @@ -0,0 +1,447 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/4.Coding.rst <development_coding>` +:Translator: Alessia Mantegazza <amantegazza@vaga.pv.it> + +.. _it_development_coding: + +Scrivere codice corretto +======================== + +Nonostante ci sia molto da dire sul processo di creazione, sulla sua solidità +e sul suo orientamento alla comunità, la prova di ogni progetto di sviluppo +del kernel si trova nel codice stesso. È il codice che sarà esaminato dagli +altri sviluppatori ed inserito (o no) nel ramo principale. Quindi è la +qualità di questo codice che determinerà il successo finale del progetto. + +Questa sezione esaminerà il processo di codifica. Inizieremo con uno sguardo +sulle diverse casistiche nelle quali gli sviluppatori kernel possono +sbagliare. Poi, l'attenzione si sposterà verso "il fare le cose +correttamente" e sugli strumenti che possono essere utili in questa missione. + +Trappole +-------- + +Lo stile del codice +******************* + +Il kernel ha da tempo delle norme sullo stile di codifica che sono descritte in +:ref:`Documentation/translations/it_IT/process/coding-style.rst <codingstyle>`. +Per la maggior parte del tempo, la politica descritta in quel file è stata +praticamente informativa. Ne risulta che ci sia una quantità sostanziale di +codice nel kernel che non rispetta le linee guida relative allo stile. +La presenza di quel codice conduce a due distinti pericoli per gli +sviluppatori kernel. + +Il primo di questi è credere che gli standard di codifica del kernel +non sono importanti e possono non essere applicati. La verità è che +aggiungere nuovo codice al kernel è davvero difficile se questo non +rispetta le norme; molti sviluppatori richiederanno che il codice sia +riformulato prima che anche solo lo revisionino. Una base di codice larga +quanto il kernel richiede una certa uniformità, in modo da rendere possibile +per gli sviluppatori una comprensione veloce di ogni sua parte. Non ci sono, +quindi, più spazi per un codice formattato alla carlona. + +Occasionalmente, lo stile di codifica del kernel andrà in conflitto con lo +stile richiesto da un datore di lavoro. In alcuni casi, lo stile del kernel +dovrà prevalere prima che il codice venga inserito. Mettere il codice +all'interno del kernel significa rinunciare a un certo grado di controllo +in differenti modi - incluso il controllo sul come formattare il codice. + +L’altra trappola è quella di pensare che il codice già presente nel kernel +abbia urgentemente bisogno di essere sistemato. Gli sviluppatori potrebbero +iniziare a generare patch che correggono lo stile come modo per prendere +famigliarità con il processo, o come modo per inserire i propri nomi nei +changelog del kernel – o entrambe. La comunità di sviluppo vede un attività +di codifica puramente correttiva come "rumore"; queste attività riceveranno +una fredda accoglienza. Di conseguenza è meglio evitare questo tipo di patch. +Mentre si lavora su un pezzo di codice è normale correggerne anche lo stile, +ma le modifiche di stile non dovrebbero essere fatte fini a se stesse. + +Il documento sullo stile del codice non dovrebbe essere letto come una legge +assoluta che non può mai essere trasgredita. Se c’è un a buona ragione +(per esempio, una linea che diviene poco leggibile se divisa per rientrare +nel limite di 80 colonne), fatelo e basta. + +Notate che potete utilizzare lo strumento “clang-format” per aiutarvi con +le regole, per una riformattazione automatica e veloce del vostro codice +e per revisionare interi file per individuare errori nello stile di codifica, +refusi e possibili miglioramenti. Inoltre è utile anche per classificare gli +``#includes``, per allineare variabili/macro, per testi derivati ed altri +compiti del genere. Consultate il file +:ref:`Documentation/translations/it_IT/process/clang-format.rst <clangformat>` +per maggiori dettagli + + +Livelli di astrazione +********************* + + +I professori di Informatica insegnano ai propri studenti a fare ampio uso dei +livelli di astrazione nel nome della flessibilità e del nascondere informazioni. +Certo il kernel fa un grande uso dell'astrazione; nessun progetto con milioni +di righe di codice potrebbe fare altrimenti e sopravvivere. Ma l'esperienza +ha dimostrato che un'eccessiva o prematura astrazione può rivelarsi dannosa +al pari di una prematura ottimizzazione. L'astrazione dovrebbe essere usata +fino al livello necessario e non oltre. + +Ad un livello base, considerate una funzione che ha un argomento che viene +sempre impostato a zero da tutti i chiamanti. Uno potrebbe mantenere +quell'argomento nell'eventualità qualcuno volesse sfruttare la flessibilità +offerta. In ogni caso, tuttavia, ci sono buone possibilità che il codice +che va ad implementare questo argomento aggiuntivo, sia stato rotto in maniera +sottile, in un modo che non è mai stato notato - perché non è mai stato usato. +Oppure, quando sorge la necessità di avere più flessibilità, questo argomento +non la fornisce in maniera soddisfacente. Gli sviluppatori di Kernel, +sottopongono costantemente patch che vanno a rimuovere gli argomenti +inutilizzate; anche se, in generale, non avrebbero dovuto essere aggiunti. + +I livelli di astrazione che nascondono l'accesso all'hardware - +spesso per poter usare dei driver su diversi sistemi operativi - vengono +particolarmente disapprovati. Tali livelli oscurano il codice e possono +peggiorare le prestazioni; essi non appartengono al kernel Linux. + +D'altro canto, se vi ritrovate a dover copiare una quantità significativa di +codice proveniente da un altro sottosistema del kernel, è tempo di chiedersi +se, in effetti, non avrebbe più senso togliere parte di quel codice e metterlo +in una libreria separata o di implementare quella funzionalità ad un livello +più elevato. Non c'è utilità nel replicare lo stesso codice per tutto +il kernel. + + +#ifdef e l'uso del preprocessore in generale +******************************************** + +Il preprocessore C sembra essere una fonte di attrazione per qualche +programmatore C, che ci vede una via per ottenere una grande flessibilità +all'interno di un file sorgente. Ma il preprocessore non è scritto in C, +e un suo massiccio impiego conduce a un codice che è molto più difficile +da leggere per gli altri e che rende più difficile il lavoro di verifica del +compilatore. L'uso eccessivo del preprocessore è praticamente sempre il segno +di un codice che necessita di un certo lavoro di pulizia. + +La compilazione condizionata con #ifdef è, in effetti, un potente strumento, +ed esso viene usato all'interno del kernel. Ma esiste un piccolo desiderio: +quello di vedere il codice coperto solo da una leggera spolverata di +blocchi #ifdef. Come regola generale, quando possibile, l'uso di #ifdef +dovrebbe essere confinato nei file d'intestazione. Il codice compilato +condizionatamente può essere confinato a funzioni tali che, nel caso in cui +il codice non deve essere presente, diventano vuote. Il compilatore poi +ottimizzerà la chiamata alla funzione vuota rimuovendola. Il risultato è +un codice molto più pulito, più facile da seguire. + +Le macro del preprocessore C presentano una serie di pericoli, inclusi +valutazioni multiple di espressioni che hanno effetti collaterali e non +garantiscono una sicurezza rispetto ai tipi. Se siete tentati dal definire +una macro, considerate l'idea di creare invece una funzione inline. Il codice +che ne risulterà sarà lo stesso, ma le funzioni inline sono più leggibili, +non considerano i propri argomenti più volte, e permettono al compilatore di +effettuare controlli sul tipo degli argomenti e del valore di ritorno. + + +Funzioni inline +*************** + +Comunque, anche le funzioni inline hanno i loro pericoli. I programmatori +potrebbero innamorarsi dell'efficienza percepita derivata dalla rimozione +di una chiamata a funzione. Queste funzioni, tuttavia, possono ridurre le +prestazioni. Dato che il loro codice viene replicato ovunque vi sia una +chiamata ad esse, si finisce per gonfiare le dimensioni del kernel compilato. +Questi, a turno, creano pressione sulla memoria cache del processore, e questo +può causare rallentamenti importanti. Le funzioni inline, di norma, dovrebbero +essere piccole e usate raramente. Il costo di una chiamata a funzione, dopo +tutto, non è così alto; la creazione di molte funzioni inline è il classico +esempio di un'ottimizzazione prematura. + +In generale, i programmatori del kernel ignorano gli effetti della cache a +loro rischio e pericolo. Il classico compromesso tempo/spazio teorizzato +all'inizio delle lezioni sulle strutture dati spesso non si applica +all'hardware moderno. Lo spazio *è* tempo, in questo senso un programma +più grande sarà più lento rispetto ad uno più compatto. + +I compilatori più recenti hanno preso un ruolo attivo nel decidere se +una data funzione deve essere resa inline oppure no. Quindi l'uso +indiscriminato della parola chiave "inline" potrebbe non essere non solo +eccessivo, ma anche irrilevante. + +Sincronizzazione +**************** + +Nel maggio 2006, il sistema di rete "Devicescape" fu rilasciato in pompa magna +sotto la licenza GPL e reso disponibile per la sua inclusione nella ramo +principale del kernel. Questa donazione fu una notizia bene accolta; +il supporto per le reti senza fili era considerata, nel migliore dei casi, +al di sotto degli standard; il sistema Deviscape offrì la promessa di una +risoluzione a tale situazione. Tuttavia, questo codice non fu inserito nel +ramo principale fino al giugno del 2007 (2.6.22). Cosa accadde? + +Quel codice mostrava numerosi segnali di uno sviluppo in azienda avvenuto +a porte chiuse. Ma in particolare, un grosso problema fu che non fu +progettato per girare in un sistema multiprocessore. Prima che questo +sistema di rete (ora chiamato mac80211) potesse essere inserito, fu necessario +un lavoro sugli schemi di sincronizzazione. + +Una volta, il codice del kernel Linux poteva essere sviluppato senza pensare +ai problemi di concorrenza presenti nei sistemi multiprocessore. Ora, +comunque, questo documento è stato scritto su di un portatile dual-core. +Persino su sistemi a singolo processore, il lavoro svolto per incrementare +la capacità di risposta aumenterà il livello di concorrenza interno al kernel. +I giorni nei quali il codice poteva essere scritto senza pensare alla +sincronizzazione sono da passati tempo. + +Ogni risorsa (strutture dati, registri hardware, etc.) ai quali si potrebbe +avere accesso simultaneo da più di un thread deve essere sincronizzato. Il +nuovo codice dovrebbe essere scritto avendo tale accortezza in testa; +riadattare la sincronizzazione a posteriori è un compito molto più difficile. +Gli sviluppatori del kernel dovrebbero prendersi il tempo di comprendere bene +le primitive di sincronizzazione, in modo da sceglier lo strumento corretto +per eseguire un compito. Il codice che presenta una mancanza di attenzione +alla concorrenza avrà un percorso difficile all'interno del ramo principale. + +Regressioni +*********** + +Vale la pena menzionare un ultimo pericolo: potrebbe rivelarsi accattivante +l'idea di eseguire un cambiamento (che potrebbe portare a grandi +miglioramenti) che porterà ad alcune rotture per gli utenti esistenti. +Questa tipologia di cambiamento è chiamata "regressione", e le regressioni son +diventate mal viste nel ramo principale del kernel. Con alcune eccezioni, +i cambiamenti che causano regressioni saranno fermati se quest'ultime non +potranno essere corrette in tempo utile. È molto meglio quindi evitare +la regressione fin dall'inizio. + +Spesso si è argomentato che una regressione può essere giustificata se essa +porta risolve più problemi di quanti non ne crei. Perché, dunque, non fare +un cambiamento se questo porta a nuove funzionalità a dieci sistemi per +ognuno dei quali esso determina una rottura? La migliore risposta a questa +domanda ci è stata fornita da Linus nel luglio 2007: + +:: + Dunque, noi non sistemiamo bachi introducendo nuovi problemi. Quella + via nasconde insidie, e nessuno può sapere del tutto se state facendo + dei progressi reali. Sono due passi avanti e uno indietro, oppure + un passo avanti e due indietro? + +(http://lwn.net/Articles/243460/). + +Una particolare tipologia di regressione mal vista consiste in una qualsiasi +sorta di modifica all'ABI dello spazio utente. Una volta che un'interfaccia +viene esportata verso lo spazio utente, dev'essere supportata all'infinito. +Questo fatto rende la creazione di interfacce per lo spazio utente +particolarmente complicato: dato che non possono venir cambiate introducendo +incompatibilità, esse devono essere fatte bene al primo colpo. Per questa +ragione sono sempre richieste: ampie riflessioni, documentazione chiara e +ampie revisioni dell'interfaccia verso lo spazio utente. + + +Strumenti di verifica del codice +-------------------------------- +Almeno per ora la scrittura di codice priva di errori resta un ideale +irraggiungibile ai più. Quello che speriamo di poter fare, tuttavia, è +trovare e correggere molti di questi errori prima che il codice entri nel +ramo principale del kernel. A tal scopo gli sviluppatori del kernel devono +mettere insieme una schiera impressionante di strumenti che possano +localizzare automaticamente un'ampia varietà di problemi. Qualsiasi problema +trovato dal computer è un problema che non affliggerà l'utente in seguito, +ne consegue che gli strumenti automatici dovrebbero essere impiegati ovunque +possibile. + +Il primo passo consiste semplicemente nel fare attenzione agli avvertimenti +proveniente dal compilatore. Versioni moderne di gcc possono individuare +(e segnalare) un gran numero di potenziali errori. Molto spesso, questi +avvertimenti indicano problemi reali. Di regola, il codice inviato per la +revisione non dovrebbe produrre nessun avvertimento da parte del compilatore. +Per mettere a tacere gli avvertimenti, cercate di comprenderne le cause reali +e cercate di evitare le "riparazioni" che fan sparire l'avvertimento senza +però averne trovato la causa. + +Tenete a mente che non tutti gli avvertimenti sono disabilitati di default. +Costruite il kernel con "make EXTRA_CFLAGS=-W" per ottenerli tutti. + +Il kernel fornisce differenti opzioni che abilitano funzionalità di debugging; +molti di queste sono trovano all'interno del sotto menu "kernel hacking". +La maggior parte di queste opzioni possono essere attivate per qualsiasi +kernel utilizzato per lo sviluppo o a scopo di test. In particolare dovreste +attivare: + + - ENABLE_WARN_DEPRECATED, ENABLE_MUST_CHECK, e FRAME_WARN per ottenere degli + avvertimenti dedicati a problemi come l'uso di interfacce deprecate o + l'ignorare un importante valore di ritorno di una funzione. Il risultato + generato da questi avvertimenti può risultare verboso, ma non bisogna + preoccuparsi per gli avvertimenti provenienti da altre parti del kernel. + + - DEBUG_OBJECTS aggiungerà un codice per tracciare il ciclo di vita di + diversi oggetti creati dal kernel e avvisa quando qualcosa viene eseguito + fuori controllo. Se state aggiungendo un sottosistema che crea (ed + esporta) oggetti complessi propri, considerate l'aggiunta di un supporto + al debugging dell'oggetto. + + - DEBUG_SLAB può trovare svariati errori di uso e di allocazione di memoria; + esso dovrebbe esser usato dalla maggior parte dei kernel di sviluppo. + + - DEBUG_SPINLOCK, DEBUG_ATOMIC_SLEEP, e DEBUG_MUTEXES troveranno un certo + numero di errori comuni di sincronizzazione. + +Esistono ancora delle altre opzioni di debugging, di alcune di esse +discuteremo qui sotto. Alcune di esse hanno un forte impatto e non dovrebbero +essere usate tutte le volte. Ma qualche volta il tempo speso nell'capire +le opzioni disponibili porterà ad un risparmio di tempo nel breve termine. + +Uno degli strumenti di debugging più tosti è il *locking checker*, o +"lockdep". Questo strumento traccerà qualsiasi acquisizione e rilascio di +ogni *lock* (spinlock o mutex) nel sistema, l'ordine con il quale i *lock* +sono acquisiti in relazione l'uno con l'altro, l'ambiente corrente di +interruzione, eccetera. Inoltre esso può assicurare che i *lock* vengano +acquisiti sempre nello stesso ordine, che le stesse assunzioni sulle +interruzioni si applichino in tutte le occasioni, e così via. In altre parole, +lockdep può scovare diversi scenari nei quali il sistema potrebbe, in rari +casi, trovarsi in stallo. Questa tipologia di problema può essere grave +(sia per gli sviluppatori che per gli utenti) in un sistema in uso; lockdep +permette di trovare tali problemi automaticamente e in anticipo. + +In qualità di programmatore kernel diligente, senza dubbio, dovrete controllare +il valore di ritorno di ogni operazione (come l'allocazione della memoria) +poiché esso potrebbe fallire. Il nocciolo della questione è che i percorsi +di gestione degli errori, con grande probabilità, non sono mai stati +collaudati del tutto. Il codice collaudato tende ad essere codice bacato; +potrete quindi essere più a vostro agio con il vostro codice se tutti questi +percorsi fossero stati verificati un po' di volte. + +Il kernel fornisce un framework per l'inserimento di fallimenti che fa +esattamente al caso, specialmente dove sono coinvolte allocazioni di memoria. +Con l'opzione per l'inserimento dei fallimenti abilitata, una certa percentuale +di allocazione di memoria sarà destinata al fallimento; questi fallimenti +possono essere ridotti ad uno specifico pezzo di codice. Procedere con +l'inserimento dei fallimenti attivo permette al programmatore di verificare +come il codice risponde quando le cose vanno male. Consultate: +Documentation/fault-injection/fault-injection.txt per avere maggiori +informazioni su come utilizzare questo strumento. + +Altre tipologie di errori possono essere riscontrati con lo strumento di +analisi statica "sparse". Con Sparse, il programmatore può essere avvisato +circa la confusione tra gli indirizzi dello spazio utente e dello spazio +kernel, un miscuglio fra quantità big-endian e little-endian, il passaggio +di un valore intero dove ci sia aspetta un gruppo di flag, e così via. +Sparse deve essere installato separatamente (se il vostra distribuzione non +lo prevede, potete trovarlo su https://sparse.wiki.kernel.org/index.php/Main_Page); +può essere attivato sul codice aggiungendo "C=1" al comando make. + +Lo strumento "Coccinelle" (http://coccinelle.lip6.fr/) è in grado di trovare +una vasta varietà di potenziali problemi di codifica; e può inoltre proporre +soluzioni per risolverli. Un buon numero di "patch semantiche" per il kernel +sono state preparate nella cartella scripts/coccinelle; utilizzando +"make coccicheck" esso percorrerà tali patch semantiche e farà rapporto su +qualsiasi problema trovato. Per maggiori informazioni, consultate +:ref:`Documentation/dev-tools/coccinelle.rst <devtools_coccinelle>`. + +Altri errori di portabilità sono meglio scovati compilando il vostro codice +per altre architetture. Se non vi accade di avere un sistema S/390 o una +scheda di sviluppo Blackfin sotto mano, potete comunque continuare la fase +di compilazione. Un vasto numero di cross-compilatori per x86 possono +essere trovati al sito: + + http://www.kernel.org/pub/tools/crosstool/ + +Il tempo impiegato nell'installare e usare questi compilatori sarà d'aiuto +nell'evitare situazioni imbarazzanti nel futuro. + + +Documentazione +-------------- + +La documentazione è spesso stata più un'eccezione che una regola nello +sviluppo del kernel. Nonostante questo, un'adeguata documentazione aiuterà +a facilitare l'inserimento di nuovo codice nel kernel, rende la vita più +facile per gli altri sviluppatori e sarà utile per i vostri utenti. In molti +casi, la documentazione è divenuta sostanzialmente obbligatoria. + +La prima parte di documentazione per qualsiasi patch è il suo changelog. +Questi dovrebbero descrivere le problematiche risolte, la tipologia di +soluzione, le persone che lavorano alla patch, ogni effetto rilevante +sulle prestazioni e tutto ciò che può servire per la comprensione della +patch. Assicuratevi che il changelog dica *perché*, vale la pena aggiungere +la patch; un numero sorprendente di sviluppatori sbaglia nel fornire tale +informazione. + +Qualsiasi codice che aggiunge una nuova interfaccia in spazio utente - inclusi +nuovi file in sysfs o /proc - dovrebbe includere la documentazione di tale +interfaccia così da permette agli sviluppatori dello spazio utente di sapere +con cosa stanno lavorando. Consultate: Documentation/ABI/README per avere una +descrizione di come questi documenti devono essere impostati e quali +informazioni devono essere fornite. + +Il file :ref:`Documentation/translations/it_IT/admin-guide/kernel-parameters.rst <kernelparameters>` +descrive tutti i parametri di avvio del kernel. Ogni patch che aggiunga +nuovi parametri dovrebbe aggiungere nuove voci a questo file. + +Ogni nuova configurazione deve essere accompagnata da un testo di supporto +che spieghi chiaramente le opzioni e spieghi quando l'utente potrebbe volerle +selezionare. + +Per molti sottosistemi le informazioni sull'API interna sono documentate sotto +forma di commenti formattati in maniera particolare; questi commenti possono +essere estratti e formattati in differenti modi attraverso lo script +"kernel-doc". Se state lavorando all'interno di un sottosistema che ha +commenti kerneldoc dovreste mantenerli e aggiungerli, in maniera appropriata, +per le funzioni disponibili esternamente. Anche in aree che non sono molto +documentate, non c'è motivo per non aggiungere commenti kerneldoc per il +futuro; infatti, questa può essere un'attività utile per sviluppatori novizi +del kernel. Il formato di questi commenti, assieme alle informazione su come +creare modelli per kerneldoc, possono essere trovati in +:ref:`Documentation/translations/it_IT/doc-guide/ <doc_guide>`. + +Chiunque legga un ammontare significativo di codice kernel noterà che, spesso, +i commenti si fanno maggiormente notare per la loro assenza. Ancora una volta, +le aspettative verso il nuovo codice sono più alte rispetto al passato; +inserire codice privo di commenti sarà più difficile. Detto ciò, va aggiunto +che non si desiderano commenti prolissi per il codice. Il codice dovrebbe +essere, di per sé, leggibile, con dei commenti che spieghino gli aspetti più +sottili. + +Determinate cose dovrebbero essere sempre commentate. L'uso di barriere +di memoria dovrebbero essere accompagnate da una riga che spieghi perché sia +necessaria. Le regole di sincronizzazione per le strutture dati, generalmente, +necessitano di una spiegazioni da qualche parte. Le strutture dati più +importanti, in generale, hanno bisogno di una documentazione onnicomprensiva. +Le dipendenze che non sono ovvie tra bit separati di codice dovrebbero essere +indicate. Tutto ciò che potrebbe indurre un inserviente del codice a fare +una "pulizia" incorretta, ha bisogno di un commento che dica perché è stato +fatto in quel modo. E così via. + +Cambiamenti interni dell'API +---------------------------- + +L'interfaccia binaria fornita dal kernel allo spazio utente non può essere +rotta tranne che in circostanze eccezionali. L'interfaccia di programmazione +interna al kernel, invece, è estremamente fluida e può essere modificata al +bisogno. Se vi trovate a dover lavorare attorno ad un'API del kernel o +semplicemente non state utilizzando una funzionalità offerta perché questa +non rispecchia i vostri bisogni, allora questo potrebbe essere un segno che +l'API ha bisogno di essere cambiata. In qualità di sviluppatore del kernel, +hai il potere di fare questo tipo di modifica. + +Ci sono ovviamente alcuni punti da cogliere. I cambiamenti API possono essere +fatti, ma devono essere giustificati. Quindi ogni patch che porta ad una +modifica dell'API interna dovrebbe essere accompagnata da una descrizione +della modifica in sé e del perché essa è necessaria. Questo tipo di +cambiamenti dovrebbero, inoltre, essere fatti in una patch separata, invece di +essere sepolti all'interno di una patch più grande. + +L'altro punto da cogliere consiste nel fatto che uno sviluppatore che +modifica l'API deve, in generale, essere responsabile della correzione +di tutto il codice del kernel che viene rotto per via della sua modifica. +Per una funzione ampiamente usata, questo compito può condurre letteralmente +a centinaia o migliaia di modifiche, molte delle quali sono in conflitto con +il lavoro svolto da altri sviluppatori. Non c'è bisogno di dire che questo +può essere un lavoro molto grosso, quindi è meglio essere sicuri che la +motivazione sia ben solida. Notate che lo strumento Coccinelle può fornire +un aiuto con modifiche estese dell'API. + +Quando viene fatta una modifica API incompatibile, una persona dovrebbe, +quando possibile, assicurarsi che quel codice non aggiornato sia trovato +dal compilatore. Questo vi aiuterà ad essere sicuri d'avere trovato, +tutti gli usi di quell'interfaccia. Inoltre questo avviserà gli sviluppatori +di codice fuori dal kernel che c'è un cambiamento per il quale è necessario del +lavoro. Il supporto al codice fuori dal kernel non è qualcosa di cui gli +sviluppatori del kernel devono preoccuparsi, ma non dobbiamo nemmeno rendere +più difficile del necessario la vita agli sviluppatori di questo codice. diff --git a/Documentation/translations/it_IT/process/5.Posting.rst b/Documentation/translations/it_IT/process/5.Posting.rst new file mode 100644 index 000000000000..b979266aa884 --- /dev/null +++ b/Documentation/translations/it_IT/process/5.Posting.rst @@ -0,0 +1,348 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/5.Posting.rst <development_posting>` +:Translator: Federico Vaga <federico.vaga@vaga.pv.it> + +.. _it_development_posting: + +Pubblicare modifiche +==================== + +Prima o poi arriva il momento in cui il vostro lavoro è pronto per essere +presentato alla comunità per una revisione ed eventualmente per la sua +inclusione nel ramo principale del kernel. Com'era prevedibile, +la comunità di sviluppo del kernel ha elaborato un insieme di convenzioni +e di procedure per la pubblicazione delle patch; seguirle renderà la vita +più facile a tutti quanti. Questo documento cercherà di coprire questi +argomenti con un ragionevole livello di dettaglio; più informazioni possono +essere trovare nella cartella 'Documentation', nei file +:ref:`translations/it_IT/process/submitting-patches.rst <it_submittingpatches>`, +:ref:`translations/it_IT/process/submitting-drivers.rst <it_submittingdrivers>`, e +:ref:`translations/it_IT/process/submit-checklist.rst <it_submitchecklist>`. + + +Quando pubblicarle +------------------ + +C'è sempre una certa resistenza nel pubblicare patch finché non sono +veramente "pronte". Per semplici patch questo non è un problema. +Ma quando il lavoro è di una certa complessità, c'è molto da guadagnare +dai riscontri che la comunità può darvi prima che completiate il lavoro. +Dovreste considerare l'idea di pubblicare un lavoro incompleto, o anche +preparare un ramo git disponibile agli sviluppatori interessati, cosicché +possano stare al passo col vostro lavoro in qualunque momento. + +Quando pubblicate del codice che non è considerato pronto per l'inclusione, +è bene che lo diciate al momento della pubblicazione. Inoltre, aggiungete +informazioni sulle cose ancora da sviluppare e sui problemi conosciuti. +Poche persone guarderanno delle patch che si sa essere fatte a metà, +ma quelli che lo faranno penseranno di potervi aiutare a condurre il vostro +sviluppo nella giusta direzione. + + +Prima di creare patch +--------------------- + +Ci sono un certo numero di cose che dovreste fare prima di considerare +l'invio delle patch alla comunità di sviluppo. Queste cose includono: + + - Verificare il codice fino al massimo che vi è consentito. Usate gli + strumenti di debug del kernel, assicuratevi che il kernel compili con + tutte le più ragionevoli combinazioni d'opzioni, usate cross-compilatori + per compilare il codice per differenti architetture, eccetera. + + - Assicuratevi che il vostro codice sia conforme alla linee guida del + kernel sullo stile del codice. + + - La vostra patch ha delle conseguenze in termini di prestazioni? + Se è così, dovreste eseguire dei *benchmark* che mostrino il loro + impatto (anche positivo); un riassunto dei risultati dovrebbe essere + incluso nella patch. + + - Siate certi d'avere i diritti per pubblicare il codice. Se questo + lavoro è stato fatto per un datore di lavoro, egli avrà dei diritti su + questo lavoro e dovrà quindi essere d'accordo alla sua pubblicazione + con una licenza GPL + +Come regola generale, pensarci un po' di più prima di inviare il codice +ripaga quasi sempre lo sforzo. + + +Preparazione di una patch +------------------------- + +La preparazione delle patch per la pubblicazione può richiedere una quantità +di lavoro significativa, ma, ripetiamolo ancora, generalmente sconsigliamo +di risparmiare tempo in questa fase, anche sul breve periodo. + +Le patch devono essere preparate per una specifica versione del kernel. +Come regola generale, una patch dovrebbe basarsi sul ramo principale attuale +così come lo si trova nei sorgenti git di Linus. Quando vi basate sul ramo +principale, cominciate da un punto di rilascio ben noto - uno stabile o +un -rc - piuttosto che creare il vostro ramo da quello principale in un punto +a caso. + +Per facilitare una revisione e una verifica più estesa, potrebbe diventare +necessaria la produzione di versioni per -mm, linux-next o i sorgenti di un +sottosistema. Basare questa patch sui suddetti sorgenti potrebbe richiedere +un lavoro significativo nella risoluzione dei conflitti e nella correzione dei +cambiamenti di API; questo potrebbe variare a seconda dell'area d'interesse +della vostra patch e da quello che succede altrove nel kernel. + +Solo le modifiche più semplici dovrebbero essere preparate come una singola +patch; tutto il resto dovrebbe essere preparato come una serie logica di +modifiche. Spezzettare le patch è un po' un'arte; alcuni sviluppatori +passano molto tempo nel capire come farlo in modo che piaccia alla comunità. +Ci sono alcune regole spannometriche, che comunque possono aiutare +considerevolmente: + + - La serie di patch che pubblicherete, quasi sicuramente, non sarà + come quella che trovate nel vostro sistema di controllo di versione. + Invece, le vostre modifiche dovranno essere considerate nella loro forma + finale, e quindi separate in parti che abbiano un senso. Gli sviluppatori + sono interessati in modifiche che siano discrete e indipendenti, non + alla strada che avete percorso per ottenerle. + + - Ogni modifica logicamente indipendente dovrebbe essere preparata come una + patch separata. Queste modifiche possono essere piccole ("aggiunto un + campo in questa struttura") o grandi (l'aggiunta di un driver nuovo, + per esempio), ma dovrebbero essere concettualmente piccole da permettere + una descrizione in una sola riga. Ogni patch dovrebbe fare modifiche + specifiche che si possano revisionare indipendentemente e di cui si possa + verificare la veridicità. + + - Giusto per riaffermare quando detto sopra: non mischiate diversi tipi di + modifiche nella stessa patch. Se una modifica corregge un baco critico + per la sicurezza, riorganizza alcune strutture, e riformatta il codice, + ci sono buone probabilità che venga ignorata e che la correzione importante + venga persa. + + - Ogni modifica dovrebbe portare ad un kernel che compila e funziona + correttamente; se la vostra serie di patch si interrompe a metà il + risultato dovrebbe essere comunque un kernel funzionante. L'applicazione + parziale di una serie di patch è uno scenario comune nel quale il + comando "git bisect" viene usato per trovare delle regressioni; se il + risultato è un kernel guasto, renderete la vita degli sviluppatori più + difficile così come quella di chi s'impegna nel nobile lavoro di + scovare i problemi. + + - Però, non strafate. Una volta uno sviluppatore pubblicò una serie di 500 + patch che modificavano un unico file - un atto che non lo rese la persona + più popolare sulla lista di discussione del kernel. Una singola patch + può essere ragionevolmente grande fintanto che contenga un singolo + cambiamento *logico*. + + - Potrebbe essere allettante l'idea di aggiungere una nuova infrastruttura + come una serie di patch, ma di lasciare questa infrastruttura inutilizzata + finché l'ultima patch della serie non abilita tutto quanto. Quando è + possibile, questo dovrebbe essere evitato; se questa serie aggiunge delle + regressioni, "bisect" indicherà quest'ultima patch come causa del + problema anche se il baco si trova altrove. Possibilmente, quando una + patch aggiunge del nuovo codice dovrebbe renderlo attivo immediatamente. + +Lavorare per creare la serie di patch perfetta potrebbe essere frustrante +perché richiede un certo tempo e soprattutto dopo che il "vero lavoro" è +già stato fatto. Quando ben fatto, comunque, è tempo ben speso. + + +Formattazione delle patch e i changelog +--------------------------------------- + +Quindi adesso avete una serie perfetta di patch pronte per la pubblicazione, +ma il lavoro non è davvero finito. Ogni patch deve essere preparata con +un messaggio che spieghi al resto del mondo, in modo chiaro e veloce, +il suo scopo. Per ottenerlo, ogni patch sarà composta dai seguenti elementi: + + - Un campo opzionale "From" col nome dell'autore della patch. Questa riga + è necessaria solo se state passando la patch di qualcun altro via email, + ma nel dubbio non fa di certo male aggiungerlo. + + - Una descrizione di una riga che spieghi cosa fa la patch. Questo + messaggio dovrebbe essere sufficiente per far comprendere al lettore lo + scopo della patch senza altre informazioni. Questo messaggio, + solitamente, presenta in testa il nome del sottosistema a cui si riferisce, + seguito dallo scopo della patch. Per esempio: + + :: + + gpio: fix build on CONFIG_GPIO_SYSFS=n + + - Una riga bianca seguita da una descrizione dettagliata della patch. + Questa descrizione può essere lunga tanto quanto serve; dovrebbe spiegare + cosa fa e perché dovrebbe essere aggiunta al kernel. + + - Una o più righe etichette, con, minimo, una riga *Signed-off-by:* + col nome dall'autore della patch. Queste etichette verranno descritte + meglio più avanti. + +Gli elementi qui sopra, assieme, formano il changelog di una patch. +Scrivere un buon changelog è cruciale ma è spesso un'arte trascurata; +vale la pena spendere qualche parola in più al riguardo. Quando scrivete +un changelog dovreste tenere ben presente che molte persone leggeranno +le vostre parole. Queste includono i manutentori di un sotto-sistema, e i +revisori che devono decidere se la patch debba essere inclusa o no, +le distribuzioni e altri manutentori che cercano di valutare se la patch +debba essere applicata su kernel più vecchi, i cacciatori di bachi che si +chiederanno se la patch è la causa di un problema che stanno cercando, +gli utenti che vogliono sapere com'è cambiato il kernel, e molti altri. +Un buon changelog fornisce le informazioni necessarie a tutte queste +persone nel modo più diretto e conciso possibile. + +A questo scopo, la riga riassuntiva dovrebbe descrivere gli effetti della +modifica e la motivazione della patch nel modo migliore possibile nonostante +il limite di una sola riga. La descrizione dettagliata può spiegare meglio +i temi e fornire maggiori informazioni. Se una patch corregge un baco, +citate, se possibile, il commit che lo introdusse (e per favore, quando +citate un commit aggiungete sia il suo identificativo che il titolo), +Se il problema è associabile ad un file di log o all' output del compilatore, +includeteli al fine d'aiutare gli altri a trovare soluzioni per lo stesso +problema. Se la modifica ha lo scopo di essere di supporto a sviluppi +successivi, ditelo. Se le API interne vengono cambiate, dettagliate queste +modifiche e come gli altri dovrebbero agire per applicarle. In generale, +più riuscirete ad entrare nei panni di tutti quelli che leggeranno il +vostro changelog, meglio sarà il changelog (e il kernel nel suo insieme). + +Non serve dirlo, un changelog dovrebbe essere il testo usato nel messaggio +di commit in un sistema di controllo di versione. Sarà seguito da: + + - La patch stessa, nel formato unificato per patch ("-u"). Usare + l'opzione "-p" assocerà alla modifica il nome della funzione alla quale + si riferisce, rendendo il risultato più facile da leggere per gli altri. + +Dovreste evitare di includere nelle patch delle modifiche per file +irrilevanti (quelli generati dal processo di generazione, per esempio, o i file +di backup del vostro editor). Il file "dontdiff" nella cartella Documentation +potrà esservi d'aiuto su questo punto; passatelo a diff con l'opzione "-X". + +Le etichette sopra menzionante sono usate per descrivere come i vari +sviluppatori sono stati associati allo sviluppo di una patch. Sono descritte +in dettaglio nel documento :ref:`translations/it_IT/process/submitting-patches.rst <it_submittingpatches>`; +quello che segue è un breve riassunto. Ognuna di queste righe ha il seguente +formato: + +:: + + tag: Full Name <email address> optional-other-stuff + +Le etichette in uso più comuni sono: + + - Signed-off-by: questa è la certificazione che lo sviluppatore ha il diritto + di sottomettere la patch per l'integrazione nel kernel. Questo rappresenta + il consenso verso il certificato d'origine degli sviluppatori, il testo + completo potrà essere trovato in + :ref:`Documentation/translations/it_IT/process/submitting-patches.rst <it_submittingpatches>`. + Codice che non presenta una firma appropriata non potrà essere integrato. + + - Co-developed-by: indica che la patch è stata sviluppata anche da un altro + sviluppatore assieme all'autore originale. Questo è utile quando più + persone lavorano sulla stessa patch. Da notare che questa persona deve + avere anche una riga "Signed-off-by:" nella patch. + + - Acked-by: indica il consenso di un altro sviluppatore (spesso il manutentore + del codice in oggetto) all'integrazione della patch nel kernel. + + - Tested-by: menziona la persona che ha verificato la patch e l'ha trovata + funzionante. + + - Reviwed-by: menziona lo sviluppatore che ha revisionato la patch; per + maggiori dettagli leggete la dichiarazione dei revisori in + :ref:`Documentation/translations/it_IT/process/submitting-patches.rst <it_submittingpatches>` + + - Reported-by: menziona l'utente che ha riportato il problema corretto da + questa patch; quest'etichetta viene usata per dare credito alle persone + che hanno verificato il codice e ci hanno fatto sapere quando le cose non + funzionavano correttamente. + + - Cc: la persona menzionata ha ricevuto una copia della patch ed ha avuto + l'opportunità di commentarla. + +State attenti ad aggiungere queste etichette alla vostra patch: solo +"Cc:" può essere aggiunta senza il permesso esplicito della persona menzionata. + +Inviare la modifica +------------------- + +Prima di inviare la vostra patch, ci sarebbero ancora un paio di cose di cui +dovreste aver cura: + + - Siete sicuri che il vostro programma di posta non corromperà le patch? + Le patch che hanno spazi bianchi in libertà o andate a capo aggiunti + dai programmi di posta non funzioneranno per chi le riceve, e spesso + non verranno nemmeno esaminate in dettaglio. Se avete un qualsiasi dubbio, + inviate la patch a voi stessi e verificate che sia integra. + + :ref:`Documentation/translations/it_IT/process/email-clients.rst <it_email_clients>` + contiene alcuni suggerimenti utili sulla configurazione dei programmi + di posta al fine di inviare patch. + + - Siete sicuri che la vostra patch non contenga sciocchi errori? Dovreste + sempre processare le patch con scripts/checkpatch.pl e correggere eventuali + problemi riportati. Per favore tenete ben presente che checkpatch.pl non è + più intelligente di voi, nonostante sia il risultato di un certa quantità di + ragionamenti su come debba essere una patch per il kernel. Se seguire + i suggerimenti di checkpatch.pl rende il codice peggiore, allora non fatelo. + +Le patch dovrebbero essere sempre inviate come testo puro. Per favore non +inviatele come allegati; questo rende molto più difficile, per i revisori, +citare parti della patch che si vogliono commentare. Invece, mettete la vostra +patch direttamente nel messaggio. + +Quando inviate le patch, è importante inviarne una copia a tutte le persone che +potrebbero esserne interessate. Al contrario di altri progetti, il kernel +incoraggia le persone a peccare nell'invio di tante copie; non presumente che +le persone interessate vedano i vostri messaggi sulla lista di discussione. +In particolare le copie dovrebbero essere inviate a: + + - I manutentori dei sottosistemi affetti della modifica. Come descritto + in precedenza, il file MAINTAINERS è il primo luogo dove cercare i nomi + di queste persone. + + - Altri sviluppatori che hanno lavorato nello stesso ambiente - specialmente + quelli che potrebbero lavorarci proprio ora. Usate git potrebbe essere + utile per vedere chi altri ha modificato i file su cui state lavorando. + + - Se state rispondendo a un rapporto su un baco, o a una richiesta di + funzionalità, includete anche gli autori di quei rapporti/richieste. + + - Inviate una copia alle liste di discussione interessate, o, se nient'altro + è adatto, alla lista linux-kernel + + - Se state correggendo un baco, pensate se la patch dovrebbe essere inclusa + nel prossimo rilascio stabile. Se è così, la lista di discussione + stable@vger.kernel.org dovrebbe riceverne una copia. Aggiungete anche + l'etichetta "Cc: stable@vger.kernel.org" nella patch stessa; questo + permetterà alla squadra *stable* di ricevere una notifica quando questa + correzione viene integrata nel ramo principale. + +Quando scegliete i destinatari della patch, è bene avere un'idea di chi +pensiate che sia colui che, eventualmente, accetterà la vostra patch e +la integrerà. Nonostante sia possibile inviare patch direttamente a +Linus Torvalds, e lasciare che sia lui ad integrarle,solitamente non è la +strada migliore da seguire. Linus è occupato, e ci sono dei manutentori di +sotto-sistema che controllano una parte specifica del kernel. Solitamente, +vorreste che siano questi manutentori ad integrare le vostre patch. Se non +c'è un chiaro manutentore, l'ultima spiaggia è spesso Andrew Morton. + +Le patch devono avere anche un buon oggetto. Il tipico formato per l'oggetto +di una patch assomiglia a questo: + +:: + + [PATCH nn/mm] subsys: one-line description of the patch + +dove "nn" è il numero ordinale della patch, "mm" è il numero totale delle patch +nella serie, e "subsys" è il nome del sottosistema interessato. Chiaramente, +nn/mm può essere omesso per una serie composta da una singola patch. + +Se avete una significative serie di patch, è prassi inviare una descrizione +introduttiva come parte zero. Tuttavia questa convenzione non è universalmente +seguita; se la usate, ricordate che le informazioni nell'introduzione non +faranno parte del changelog del kernel. Quindi per favore, assicuratevi che +ogni patch abbia un changelog completo. + +In generale, la seconda parte e quelle successive di una patch "composta" +dovrebbero essere inviate come risposta alla prima, cosicché vengano viste +come un unico *thread*. Strumenti come git e quilt hanno comandi per inviare +gruppi di patch con la struttura appropriata. Se avete una serie lunga +e state usando git, per favore state alla larga dall'opzione --chain-reply-to +per evitare di creare un annidamento eccessivo. diff --git a/Documentation/translations/it_IT/process/6.Followthrough.rst b/Documentation/translations/it_IT/process/6.Followthrough.rst new file mode 100644 index 000000000000..df7d5fb28832 --- /dev/null +++ b/Documentation/translations/it_IT/process/6.Followthrough.rst @@ -0,0 +1,240 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/6.Followthrough.rst <development_followthrough>` +:Translator: Alessia Mantegazza <amantegazza@vaga.pv.it> + +.. _it_development_followthrough: + +============= +Completamento +============= + +A questo punto, avete seguito le linee guida fino a questo punto e, con +l'aggiunta delle vostre capacità ingegneristiche, avete pubblicato una serie +perfetta di patch. Uno dei più grandi errori che possono essere commessi +persino da sviluppatori kernel esperti è quello di concludere che il +lavoro sia ormai finito. In verità, la pubblicazione delle patch +simboleggia una transizione alla fase successiva del processo, con, +probabilmente, ancora un po' di lavoro da fare. + +È raro che una modifica sia così bella alla sua prima pubblicazione che non +ci sia alcuno spazio di miglioramento. Il programma di sviluppo del kernel +riconosce questo fatto e quindi, è fortemente orientato al miglioramento +del codice pubblicato. Voi, in qualità di autori del codice, dovrete +lavorare con la comunità del kernel per assicurare che il vostro codice +mantenga gli standard qualitativi richiesti. Un fallimento in questo +processo è quasi come impedire l'inclusione delle vostre patch nel +ramo principale. + +Lavorare con i revisori +======================= + +Una patch che abbia una certa rilevanza avrà ricevuto numerosi commenti +da parte di altri sviluppatori dato che avranno revisionato il codice. +Lavorare con i revisori può rivelarsi, per molti sviluppatori, la parte +più intimidatoria del processo di sviluppo del kernel. La vita può esservi +resa molto più facile se tenete presente alcuni dettagli: + + - Se avete descritto la vostra modifica correttamente, i revisori ne + comprenderanno il valore e il perché vi siete presi il disturbo di + scriverla. Ma tale valore non li tratterrà dal porvi una domanda + fondamentale: come verrà mantenuto questo codice nel kernel nei prossimi + cinque o dieci anni? Molti dei cambiamenti che potrebbero esservi + richiesti - da piccoli problemi di stile a sostanziali ristesure - + vengono dalla consapevolezza che Linux resterà in circolazione e in + continuo sviluppo ancora per diverse decadi. + + - La revisione del codice è un duro lavoro, ed è un mestiere poco + riconosciuto; le persone ricordano chi ha scritto il codice, ma meno + fama è attribuita a chi lo ha revisionato. Quindi i revisori potrebbero + divenire burberi, specialmente quando vendono i medesimi errori venire + fatti ancora e ancora. Se ricevete una revisione che vi sembra abbia + un tono arrabbiato, insultante o addirittura offensivo, resistente alla + tentazione di rispondere a tono. La revisione riguarda il codice e non + la persona, e i revisori non vi stanno attaccando personalmente. + + - Similarmente, i revisori del codice non stanno cercando di promuovere + i loro interessi a vostre spese. Gli sviluppatori del kernel spesso si + aspettano di lavorare sul kernel per anni, ma sanno che il loro datore + di lavoro può cambiare. Davvero, senza praticamente eccezioni, loro + stanno lavorando per la creazione del miglior kernel possibile; non + stanno cercando di creare un disagio ad aziende concorrenti. + +Quello che si sta cercando di dire è che, quando i revisori vi inviano degli +appunti dovete fare attenzione alle osservazioni tecniche che vi stanno +facendo. Non lasciate che il loro modo di esprimersi o il vostro orgoglio +impediscano che ciò accada. Quando avete dei suggerimenti sulla revisione, +prendetevi il tempo per comprendere cosa il revisore stia cercando di +comunicarvi. Se possibile, sistemate le cose che il revisore vi chiede di +modificare. E rispondete al revisore ringraziandolo e spiegando come +intendete fare. + +Notate che non dovete per forza essere d'accordo con ogni singola modifica +suggerita dai revisori. Se credete che il revisore non abbia compreso +il vostro codice, spiegateglielo. Se avete un'obiezione tecnica da fargli +su di una modifica suggerita, spiegatela inserendo anche la vostra soluzione +al problema. Se la vostra spiegazione ha senso, il revisore la accetterà. +Tuttavia, la vostra motivazione potrebbe non essere del tutto persuasiva, +specialmente se altri iniziano ad essere d'accordo con il revisore. +Prendetevi quindi un po' di tempo per pensare ancora alla cosa. Può risultare +facile essere accecati dalla propria soluzione al punto che non realizzate che +c'è qualcosa di fondamentalmente sbagliato o, magari, non state nemmeno +risolvendo il problema giusto. + +Andrew Morton suggerisce che ogni suggerimento di revisione che non è +presente nella modifica del codice dovrebbe essere inserito in un commento +aggiuntivo; ciò può essere d'aiuto ai futuri revisori nell'evitare domande +che sorgono al primo sguardo. + +Un errore fatale è quello di ignorare i commenti di revisione nella speranza +che se ne andranno. Non andranno via. Se pubblicherete nuovamente il +codice senza aver risposto ai commenti ricevuti, probabilmente le vostre +modifiche non andranno da nessuna parte. + +Parlando di ripubblicazione del codice: per favore tenete a mente che i +revisori non ricorderanno tutti i dettagli del codice che avete pubblicato +l'ultima volta. Quindi è sempre una buona idea quella di ricordare ai +revisori le questioni sollevate precedetemene e come le avete risolte. +I revisori non dovrebbero star lì a cercare all'interno degli archivi per +famigliarizzare con ciò che è stato detto l'ultima volta; se li aiutate +in questo senso, saranno di umore migliore quando riguarderanno il vostro +codice. + +Se invece avete cercato di far tutto correttamente ma le cose continuano +a non andar bene? Molti disaccordi di natura tecnica possono essere risolti +attraverso la discussione, ma ci sono volte dove qualcuno deve prendere +una decisione. Se credete veramente che tale decisione andrà contro di voi +ingiustamente, potete sempre tentare di rivolgervi a qualcuno più +in alto di voi. Per cose di questo genere la persona con più potere è +Andrew Morton. Andrew è una figura molto rispettata all'interno della +comunità di sviluppo del kernel; lui può spesso sbrogliare situazioni che +sembrano irrimediabilmente bloccate. Rivolgersi ad Andrew non deve essere +fatto alla leggera, e non deve essere fatto prima di aver esplorato tutte +le altre alternative. E tenete a mente, ovviamente, che nemmeno lui +potrebbe non essere d'accordo con voi. + +Cosa accade poi +=============== + +Se la modifica è ritenuta un elemento valido da essere aggiunta al kernel, +e una volta che la maggior parte degli appunti dei revisori sono stati +sistemati, il passo successivo solitamente è quello di entrare in un +sottosistema gestito da un manutentore. Come ciò avviene dipende dal +sottosistema medesimo; ogni manutentore ha il proprio modo di fare le cose. +In particolare, ci potrebbero essere diversi sorgenti - uno, magari, dedicato +alle modifiche pianificate per la finestra di fusione successiva, e un altro +per il lavoro di lungo periodo. + +Per le modifiche proposte in aree per le quali non esiste un sottosistema +preciso (modifiche di gestione della memoria, per esempio), i sorgenti di +ripiego finiscono per essere -mm. Ed anche le modifiche che riguardano +più sottosistemi possono finire in quest'ultimo. + +L'inclusione nei sorgenti di un sottosistema può comportare per una patch, +un alto livello di visibilità. Ora altri sviluppatori che stanno lavorando +in quei medesimi sorgenti avranno le vostre modifiche. I sottosistemi +solitamente riforniscono anche Linux-next, rendendo i propri contenuti +visibili all'intera comunità di sviluppo. A questo punto, ci sono buone +possibilità per voi di ricevere ulteriori commenti da un nuovo gruppo di +revisori; anche a questi commenti dovrete rispondere come avete già fatto per +gli altri. + +Ciò che potrebbe accadere a questo punto, in base alla natura della vostra +modifica, riguarda eventuali conflitti con il lavoro svolto da altri. +Nella peggiore delle situazioni, i conflitti più pesanti tra modifiche possono +concludersi con la messa a lato di alcuni dei lavori svolti cosicché le +modifiche restanti possano funzionare ed essere integrate. Altre volte, la +risoluzione dei conflitti richiederà del lavoro con altri sviluppatori e, +possibilmente, lo spostamento di alcune patch da dei sorgenti a degli altri +in modo da assicurare che tutto sia applicato in modo pulito. Questo lavoro +può rivelarsi una spina nel fianco, ma consideratevi fortunati: prima +dell'avvento dei sorgenti linux-next, questi conflitti spesso emergevano solo +durante l'apertura della finestra di integrazione e dovevano essere smaltiti +in fretta. Ora essi possono essere risolti comodamente, prima dell'apertura +della finestra. + +Un giorno, se tutto va bene, vi collegherete e vedrete che la vostra patch +è stata inserita nel ramo principale de kernel. Congratulazioni! Terminati +i festeggiamenti (nel frattempo avrete inserito il vostro nome nel file +MAINTAINERS) vale la pena ricordare una piccola cosa, ma importante: il +lavoro non è ancora finito. L'inserimento nel ramo principale porta con se +nuove sfide. + +Cominciamo con il dire che ora la visibilità della vostra modifica è +ulteriormente cresciuta. Ci potrebbe portare ad una nuova fase di +commenti dagli sviluppatori che non erano ancora a conoscenza della vostra +patch. Ignorarli potrebbe essere allettante dato che non ci sono più +dubbi sull'integrazione della modifica. Resistete a tale tentazione, dovete +mantenervi disponibili agli sviluppatori che hanno domande o suggerimenti +per voi. + +Ancora più importante: l'inclusione nel ramo principale mette il vostro +codice nelle mani di un gruppo di *tester* molto più esteso. Anche se avete +contribuito ad un driver per un hardware che non è ancora disponibile, sarete +sorpresi da quante persone inseriranno il vostro codice nei loro kernel. +E, ovviamente, dove ci sono *tester*, ci saranno anche dei rapporti su +eventuali bachi. + +La peggior specie di rapporti sono quelli che indicano delle regressioni. +Se la vostra modifica causa una regressione, avrete un gran numero di +occhi puntati su di voi; la regressione deve essere sistemata il prima +possibile. Se non vorrete o non sarete capaci di sistemarla (e nessuno +lo farà per voi), la vostra modifica sarà quasi certamente rimossa durante +la fase di stabilizzazione. Oltre alla perdita di tutto il lavoro svolto +per far si che la vostra modifica fosse inserita nel ramo principale, +l'avere una modifica rimossa a causa del fallimento nel sistemare una +regressione, potrebbe rendere più difficile per voi far accettare +il vostro lavoro in futuro. + +Dopo che ogni regressione è stata affrontata, ci potrebbero essere altri +bachi ordinari da "sconfiggere". Il periodo di stabilizzazione è la +vostra migliore opportunità per sistemare questi bachi e assicurarvi che +il debutto del vostro codice nel ramo principale del kernel sia il più solido +possibile. Quindi, per favore, rispondete ai rapporti sui bachi e ponete +rimedio, se possibile, a tutti i problemi. È a questo che serve il periodo +di stabilizzazione; potete iniziare creando nuove fantastiche modifiche +una volta che ogni problema con le vecchie sia stato risolto. + +Non dimenticate che esistono altre pietre miliari che possono generare +rapporti sui bachi: il successivo rilascio stabile, quando una distribuzione +importante usa una versione del kernel nel quale è presente la vostra +modifica, eccetera. Il continuare a rispondere a questi rapporti è fonte di +orgoglio per il vostro lavoro. Se questa non è una sufficiente motivazione, +allora, è anche consigliabile considera che la comunità di sviluppo ricorda +gli sviluppatori che hanno perso interesse per il loro codice una volta +integrato. La prossima volta che pubblicherete una patch, la comunità +la valuterà anche sulla base del fatto che non sarete disponibili a +prendervene cura anche nel futuro. + + +Altre cose che posso accadere +============================= + +Un giorno, potreste aprire la vostra email e vedere che qualcuno vi ha +inviato una patch per il vostro codice. Questo, dopo tutto, è uno dei +vantaggi di avere il vostro codice "là fuori". Se siete d'accordo con +la modifica, potrete anche inoltrarla ad un manutentore di sottosistema +(assicuratevi di includere la riga "From:" cosicché l'attribuzione sia +corretta, e aggiungete una vostra firma "Signed-off-by"), oppure inviate +un "Acked-by:" e lasciate che l'autore originale la invii. + +Se non siete d'accordo con la patch, inviate una risposta educata +spiegando il perché. Se possibile, dite all'autore quali cambiamenti +servirebbero per rendere la patch accettabile da voi. C'è una certa +riluttanza nell'inserire modifiche con un conflitto fra autore +e manutentore del codice, ma solo fino ad un certo punto. Se siete visti +come qualcuno che blocca un buon lavoro senza motivo, quelle patch vi +passeranno oltre e andranno nel ramo principale in ogni caso. Nel kernel +Linux, nessuno ha potere di veto assoluto su alcun codice. Eccezione +fatta per Linus, forse. + +In rarissime occasioni, potreste vedere qualcosa di completamente diverso: +un altro sviluppatore che pubblica una soluzione differente al vostro +problema. A questo punto, c'è una buona probabilità che una delle due +modifiche non verrà integrata, e il "c'ero prima io" non è considerato +un argomento tecnico rilevante. Se la modifica di qualcun'altro rimpiazza +la vostra ed entra nel ramo principale, esiste un unico modo di reagire: +siate contenti che il vostro problema sia stato risolto e andate avanti con +il vostro lavoro. L'avere un vostro lavoro spintonato da parte in questo +modo può essere avvilente e scoraggiante, ma la comunità ricorderà come +avrete reagito anche dopo che avrà dimenticato quale fu la modifica accettata. diff --git a/Documentation/translations/it_IT/process/7.AdvancedTopics.rst b/Documentation/translations/it_IT/process/7.AdvancedTopics.rst new file mode 100644 index 000000000000..cc1cff5d23ae --- /dev/null +++ b/Documentation/translations/it_IT/process/7.AdvancedTopics.rst @@ -0,0 +1,191 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/7.AdvancedTopics.rst <development_advancedtopics>` +:Translator: Federico Vaga <federico.vaga@vaga.pv.it> + +.. _it_development_advancedtopics: + +Argomenti avanzati +================== + +A questo punto, si spera, dovreste avere un'idea su come funziona il processo +di sviluppo. Ma rimane comunque molto da imparare! Questo capitolo copre +alcuni argomenti che potrebbero essere utili per gli sviluppatori che stanno +per diventare parte integrante del processo di sviluppo del kernel. + +Gestire le modifiche con git +----------------------------- + +L'uso di un sistema distribuito per il controllo delle versioni del kernel +ebbe iniziò nel 2002 quando Linux iniziò a provare il programma proprietario +BitKeeper. Nonostante l'uso di BitKeeper fosse opinabile, di certo il suo +approccio alla gestione dei sorgenti non lo era. Un sistema distribuito per +il controllo delle versioni accelerò immediatamente lo sviluppo del kernel. +Oggigiorno, ci sono diverse alternative libere a BitKeeper. Per il meglio o il +peggio, il progetto del kernel ha deciso di usare git per gestire i sorgenti. + +Gestire le modifiche con git può rendere la vita dello sviluppatore molto +più facile, specialmente quando il volume delle modifiche cresce. +Git ha anche i suoi lati taglienti che possono essere pericolosi; è uno +strumento giovane e potente che è ancora in fase di civilizzazione da parte +dei suoi sviluppatori. Questo documento non ha lo scopo di insegnare l'uso +di git ai suoi lettori; ci sarebbe materiale a sufficienza per un lungo +documento al riguardo. Invece, qui ci concentriamo in particolare su come +git è parte del processo di sviluppo del kernel. Gli sviluppatori che +desiderassero diventare agili con git troveranno più informazioni ai +seguenti indirizzi: + + http://git-scm.com/ + + http://www.kernel.org/pub/software/scm/git/docs/user-manual.html + +e su varie guide che potrete trovare su internet. + +La prima cosa da fare prima di usarlo per produrre patch che saranno +disponibili ad altri, è quella di leggere i siti qui sopra e di acquisire una +base solida su come funziona git. Uno sviluppatore che sappia usare git +dovrebbe essere capace di ottenere una copia del repositorio principale, +esplorare la storia della revisione, registrare le modifiche, usare i rami, +eccetera. Una certa comprensione degli strumenti git per riscrivere la storia +(come ``rebase``) è altrettanto utile. Git ha i propri concetti e la propria +terminologia; un nuovo utente dovrebbe conoscere *refs*, *remote branch*, +*index*, *fast-forward merge*, *push* e *pull*, *detached head*, eccetera. +Il tutto potrebbe essere un po' intimidatorio visto da fuori, ma con un po' +di studio i concetti non saranno così difficili da capire. + +Utilizzare git per produrre patch da sottomettere via email può essere +un buon esercizio da fare mentre si sta prendendo confidenza con lo strumento. + +Quando sarete in grado di creare rami git che siano guardabili da altri, +vi servirà, ovviamente, un server dal quale sia possibile attingere le vostre +modifiche. Se avete un server accessibile da Internet, configurarlo per +eseguire git-daemon è relativamente semplice . Altrimenti, iniziano a +svilupparsi piattaforme che offrono spazi pubblici, e gratuiti (Github, +per esempio). Gli sviluppatori permanenti possono ottenere un account +su kernel.org, ma non è proprio facile da ottenere; per maggiori informazioni +consultate la pagina web http://kernel.org/faq/. + +In git è normale avere a che fare con tanti rami. Ogni linea di sviluppo +può essere separata in "rami per argomenti" e gestiti indipendentemente. +In git i rami sono facilissimi, per cui non c'è motivo per non usarli +in libertà. In ogni caso, non dovreste sviluppare su alcun ramo dal +quale altri potrebbero attingere. I rami disponibili pubblicamente dovrebbero +essere creati con attenzione; integrate patch dai rami di sviluppo +solo quando sono complete e pronte ad essere consegnate - non prima. + +Git offre alcuni strumenti che vi permettono di riscrivere la storia del +vostro sviluppo. Una modifica errata (diciamo, una che rompe la bisezione, +oppure che ha un qualche tipo di baco evidente) può essere corretta sul posto +o fatta sparire completamente dalla storia. Una serie di patch può essere +riscritta come se fosse stata scritta in cima al ramo principale di oggi, +anche se ci avete lavorato per mesi. Le modifiche possono essere spostate +in modo trasparente da un ramo ad un altro. E così via. Un uso giudizioso +di git per revisionare la storia può aiutare nella creazione di una serie +di patch pulite e con meno problemi. + +Un uso eccessivo può portare ad altri tipi di problemi, tuttavia, oltre +alla semplice ossessione per la creazione di una storia del progetto che sia +perfetta. Riscrivere la storia riscriverà le patch contenute in quella +storia, trasformando un kernel verificato (si spera) in uno da verificare. +Ma, oltre a questo, gli sviluppatori non possono collaborare se non condividono +la stessa vista sulla storia del progetto; se riscrivete la storia dalla quale +altri sviluppatori hanno attinto per i loro repositori, renderete la loro vita +molto più difficile. Quindi tenete conto di questa semplice regola generale: +la storia che avete esposto ad altri, generalmente, dovrebbe essere vista come +immutabile. + +Dunque, una volta che il vostro insieme di patch è stato reso disponibile +pubblicamente non dovrebbe essere più sovrascritto. Git tenterà di imporre +questa regola, e si rifiuterà di pubblicare nuove patch che non risultino +essere dirette discendenti di quelle pubblicate in precedenza (in altre parole, +patch che non condividono la stessa storia). È possibile ignorare questo +controllo, e ci saranno momenti in cui sarà davvero necessario riscrivere +un ramo già pubblicato. Un esempio è linux-next dove le patch vengono +spostate da un ramo all'altro al fine di evitare conflitti. Ma questo tipo +d'azione dovrebbe essere un'eccezione. Questo è uno dei motivi per cui lo +sviluppo dovrebbe avvenire in rami privati (che possono essere sovrascritti +quando lo si ritiene necessario) e reso pubblico solo quando è in uno stato +avanzato. + +Man mano che il ramo principale (o altri rami su cui avete basato le +modifiche) avanza, diventa allettante l'idea di integrare tutte le patch +per rimanere sempre aggiornati. Per un ramo privato, il *rebase* può essere +un modo semplice per rimanere aggiornati, ma questa non è un'opzione nel +momento in cui il vostro ramo è stato esposto al mondo intero. +*Merge* occasionali possono essere considerati di buon senso, ma quando +diventano troppo frequenti confondono inutilmente la storia. La tecnica +suggerita in questi casi è quella di fare *merge* raramente, e più in generale +solo nei momenti di rilascio (per esempio gli -rc del ramo principale). +Se siete nervosi circa alcune patch in particolare, potete sempre fare +dei *merge* di test in un ramo privato. In queste situazioni git "rerere" +può essere utile; questo strumento si ricorda come i conflitti di *merge* +furono risolti in passato cosicché non dovrete fare lo stesso lavoro due volte. + +Una delle lamentele più grosse e ricorrenti sull'uso di strumenti come git +è il grande movimento di patch da un repositorio all'altro che rende +facile l'integrazione nel ramo principale di modifiche mediocri, il tutto +sotto il naso dei revisori. Gli sviluppatori del kernel tendono ad essere +scontenti quando vedono succedere queste cose; preparare un ramo git con +patch che non hanno ricevuto alcuna revisione o completamente avulse, potrebbe +influire sulla vostra capacita di proporre, in futuro, l'integrazione dei +vostri rami. Citando Linus + +:: + + Potete inviarmi le vostre patch, ma per far si che io integri una + vostra modifica da git, devo sapere che voi sappiate cosa state + facendo, e ho bisogno di fidarmi *senza* dover passare tutte + le modifiche manualmente una per una. + +(http://lwn.net/Articles/224135/). + +Per evitare queste situazioni, assicuratevi che tutte le patch in un ramo +siano strettamente correlate al tema delle modifiche; un ramo "driver fixes" +non dovrebbe fare modifiche al codice principale per la gestione della memoria. +E, più importante ancora, non usate un repositorio git per tentare di +evitare il processo di revisione. Pubblicate un sommario di quello che il +vostro ramo contiene sulle liste di discussione più opportune, e , quando +sarà il momento, richiedete che il vostro ramo venga integrato in linux-next. + +Se e quando altri inizieranno ad inviarvi patch per essere incluse nel +vostro repositorio, non dovete dimenticare di revisionarle. Inoltre +assicuratevi di mantenerne le informazioni di paternità; al riguardo git "am" +fa del suo meglio, ma potreste dover aggiungere una riga "From:" alla patch +nel caso in cui sia arrivata per vie traverse. + +Quando richiedete l'integrazione, siate certi di fornire tutte le informazioni: +dov'è il vostro repositorio, quale ramo integrare, e quali cambiamenti si +otterranno dall'integrazione. Il comando git request-pull può essere d'aiuto; +preparerà una richiesta nel modo in cui gli altri sviluppatori se l'aspettano, +e verificherà che vi siate ricordati di pubblicare quelle patch su un +server pubblico. + +Revisionare le patch +-------------------- + +Alcuni lettori potrebbero avere obiezioni sulla presenza di questa sezione +negli "argomenti avanzati" sulla base che anche gli sviluppatori principianti +dovrebbero revisionare le patch. É certamente vero che non c'è modo +migliore di imparare come programmare per il kernel che guardare il codice +pubblicato dagli altri. In aggiunta, i revisori sono sempre troppo pochi; +guardando il codice potete apportare un significativo contributo all'intero +processo. + +Revisionare il codice potrebbe risultare intimidatorio, specialmente per i +nuovi arrivati che potrebbero sentirsi un po' nervosi nel questionare +il codice - in pubblico - pubblicato da sviluppatori più esperti. Perfino +il codice scritto dagli sviluppatori più esperti può essere migliorato. +Forse il suggerimento migliore per i revisori (tutti) è questo: formulate +i commenti come domande e non come critiche. Chiedere "Come viene rilasciato +il *lock* in questo percorso?" funziona sempre molto meglio che +"qui la sincronizzazione è sbagliata". + +Diversi sviluppatori revisioneranno il codice con diversi punti di vista. +Alcuni potrebbero concentrarsi principalmente sullo stile del codice e se +alcune linee hanno degli spazio bianchi di troppo. Altri si chiederanno +se accettare una modifica interamente è una cosa positiva per il kernel +o no. E altri ancora si focalizzeranno sui problemi di sincronizzazione, +l'uso eccessivo di *stack*, problemi di sicurezza, duplicazione del codice +in altri contesti, documentazione, effetti negativi sulle prestazioni, cambi +all'ABI dello spazio utente, eccetera. Qualunque tipo di revisione è ben +accetta e di valore, se porta ad avere un codice migliore nel kernel. diff --git a/Documentation/translations/it_IT/process/8.Conclusion.rst b/Documentation/translations/it_IT/process/8.Conclusion.rst new file mode 100644 index 000000000000..039bfc5a4108 --- /dev/null +++ b/Documentation/translations/it_IT/process/8.Conclusion.rst @@ -0,0 +1,85 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/8.Conclusion.rst <development_conclusion>` +:Translator: Alessia Mantegazza <amantegazza@vaga.pv.it> + +.. _it_development_conclusion: + +Per maggiori informazioni +========================= + +Esistono numerose fonti di informazioni sullo sviluppo del kernel Linux +e argomenti correlati. Primo tra questi sarà sempre la cartella Documentation +che si trova nei sorgenti kernel. + +Il file :ref:`process/howto.rst <it_process_howto>` è un punto di partenza +importante; :ref:`process/submitting-patches.rst <it_submittingpatches>` e +:ref:`process/submitting-drivers.rst <it_submittingdrivers>` sono +anch'essi qualcosa che tutti gli sviluppatori del kernel dovrebbero leggere. +Molte API interne al kernel sono documentate utilizzando il meccanismo +kerneldoc; "make htmldocs" o "make pdfdocs" possono essere usati per generare +quei documenti in HTML o PDF (sebbene le versioni di TeX di alcune +distribuzioni hanno dei limiti interni e fallisce nel processare +appropriatamente i documenti). + +Diversi siti web approfondiscono lo sviluppo del kernel ad ogni livello +di dettaglio. Il vostro autore vorrebbe umilmente suggerirvi +http://lwn.net/ come fonte; usando l'indice 'kernel' su LWN troverete +molti argomenti specifici sul kernel: + + http://lwn.net/Kernel/Index/ + +Oltre a ciò, una risorsa valida per gli sviluppatori kernel è: + + http://kernelnewbies.org/ + +E, ovviamente, una fonte da non dimenticare è http://kernel.org/, il luogo +definitivo per le informazioni sui rilasci del kernel. + +Ci sono numerosi libri sullo sviluppo del kernel: + + Linux Device Drivers, 3rd Edition (Jonathan Corbet, Alessandro + Rubini, and Greg Kroah-Hartman). In linea all'indirizzo + http://lwn.net/Kernel/LDD3/. + + Linux Kernel Development (Robert Love). + + Understanding the Linux Kernel (Daniel Bovet and Marco Cesati). + +Tutti questi libri soffrono di un errore comune: tendono a risultare in un +certo senso obsoleti dal momento che si trovano in libreria da diverso +tempo. Comunque contengono informazioni abbastanza buone. + +La documentazione per git la troverete su: + + http://www.kernel.org/pub/software/scm/git/docs/ + + http://www.kernel.org/pub/software/scm/git/docs/user-manual.html + + + +Conclusioni +=========== + +Congratulazioni a chiunque ce l'abbia fatta a terminare questo documento di +lungo-respiro. Si spera che abbia fornito un'utile comprensione d'insieme +di come il kernel Linux viene sviluppato e di come potete partecipare a +tale processo. + +Infine, quello che conta è partecipare. Qualsiasi progetto software +open-source non è altro che la somma di quello che i suoi contributori +mettono al suo interno. Il kernel Linux è cresciuto velocemente e bene +perché ha ricevuto il supporto di un impressionante gruppo di sviluppatori, +ognuno dei quali sta lavorando per renderlo migliore. Il kernel è un esempio +importante di cosa può essere fatto quando migliaia di persone lavorano +insieme verso un obiettivo comune. + +Il kernel può sempre beneficiare di una larga base di sviluppatori, tuttavia, +c'è sempre molto lavoro da fare. Ma, cosa non meno importante, molti degli +altri partecipanti all'ecosistema Linux possono trarre beneficio attraverso +il contributo al kernel. Inserire codice nel ramo principale è la chiave +per arrivare ad una qualità del codice più alta, bassa manutenzione e +bassi prezzi di distribuzione, alti livelli d'influenza sulla direzione +dello sviluppo del kernel, e molto altro. È una situazione nella quale +tutti coloro che sono coinvolti vincono. Mollate il vostro editor e +raggiungeteci; sarete più che benvenuti. diff --git a/Documentation/translations/it_IT/process/adding-syscalls.rst b/Documentation/translations/it_IT/process/adding-syscalls.rst new file mode 100644 index 000000000000..e0a64b0688a7 --- /dev/null +++ b/Documentation/translations/it_IT/process/adding-syscalls.rst @@ -0,0 +1,643 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/adding-syscalls.rst <addsyscalls>` +:Translator: Federico Vaga <federico.vaga@vaga.pv.it> + +.. _it_addsyscalls: + +Aggiungere una nuova chiamata di sistema +======================================== + +Questo documento descrive quello che è necessario sapere per aggiungere +nuove chiamate di sistema al kernel Linux; questo è da considerarsi come +un'aggiunta ai soliti consigli su come proporre nuove modifiche +:ref:`Documentation/translations/it_IT/process/submitting-patches.rst <it_submittingpatches>`. + + +Alternative alle chiamate di sistema +------------------------------------ + +La prima considerazione da fare quando si aggiunge una nuova chiamata di +sistema è quella di valutare le alternative. Nonostante le chiamate di sistema +siano il punto di interazione fra spazio utente e kernel più tradizionale ed +ovvio, esistono altre possibilità - scegliete quella che meglio si adatta alle +vostra interfaccia. + + - Se le operazioni coinvolte possono rassomigliare a quelle di un filesystem, + allora potrebbe avere molto più senso la creazione di un nuovo filesystem o + dispositivo. Inoltre, questo rende più facile incapsulare la nuova + funzionalità in un modulo kernel piuttosto che essere sviluppata nel cuore + del kernel. + + - Se la nuova funzionalità prevede operazioni dove il kernel notifica + lo spazio utente su un avvenimento, allora restituire un descrittore + di file all'oggetto corrispondente permette allo spazio utente di + utilizzare ``poll``/``select``/``epoll`` per ricevere quelle notifiche. + - Tuttavia, le operazioni che non si sposano bene con operazioni tipo + :manpage:`read(2)`/:manpage:`write(2)` dovrebbero essere implementate + come chiamate :manpage:`ioctl(2)`, il che potrebbe portare ad un'API in + un qualche modo opaca. + + - Se dovete esporre solo delle informazioni sul sistema, un nuovo nodo in + sysfs (vedere ``Documentation/translations/it_IT/filesystems/sysfs.txt``) o + in procfs potrebbe essere sufficiente. Tuttavia, l'accesso a questi + meccanismi richiede che il filesystem sia montato, il che potrebbe non + essere sempre vero (per esempio, in ambienti come namespace/sandbox/chroot). + Evitate d'aggiungere nuove API in debugfs perché questo non viene + considerata un'interfaccia di 'produzione' verso lo spazio utente. + - Se l'operazione è specifica ad un particolare file o descrittore, allora + potrebbe essere appropriata l'aggiunta di un comando :manpage:`fcntl(2)`. + Tuttavia, :manpage:`fcntl(2)` è una chiamata di sistema multiplatrice che + nasconde una notevole complessità, quindi è ottima solo quando la nuova + funzione assomiglia a quelle già esistenti in :manpage:`fcntl(2)`, oppure + la nuova funzionalità è veramente semplice (per esempio, leggere/scrivere + un semplice flag associato ad un descrittore di file). + - Se l'operazione è specifica ad un particolare processo, allora + potrebbe essere appropriata l'aggiunta di un comando :manpage:`prctl(2)`. + Come per :manpage:`fcntl(2)`, questa chiamata di sistema è un complesso + multiplatore quindi è meglio usarlo per cose molto simili a quelle esistenti + nel comando ``prctl`` oppure per leggere/scrivere un semplice flag relativo + al processo. + + +Progettare l'API: pianificare le estensioni +------------------------------------------- + +Una nuova chiamata di sistema diventerà parte dell'API del kernel, e +dev'essere supportata per un periodo indefinito. Per questo, è davvero +un'ottima idea quella di discutere apertamente l'interfaccia sulla lista +di discussione del kernel, ed è altrettanto importante pianificarne eventuali +estensioni future. + +(Nella tabella delle chiamate di sistema sono disseminati esempi dove questo +non fu fatto, assieme ai corrispondenti aggiornamenti - +``eventfd``/``eventfd2``, ``dup2``/``dup3``, ``inotify_init``/``inotify_init1``, +``pipe``/``pipe2``, ``renameat``/``renameat2`` --quindi imparate dalla storia +del kernel e pianificate le estensioni fin dall'inizio) + +Per semplici chiamate di sistema che accettano solo un paio di argomenti, +il modo migliore di permettere l'estensibilità è quello di includere un +argomento *flags* alla chiamata di sistema. Per assicurarsi che i programmi +dello spazio utente possano usare in sicurezza *flags* con diverse versioni +del kernel, verificate se *flags* contiene un qualsiasi valore sconosciuto, +in qual caso rifiutate la chiamata di sistema (con ``EINVAL``):: + + if (flags & ~(THING_FLAG1 | THING_FLAG2 | THING_FLAG3)) + return -EINVAL; + +(Se *flags* non viene ancora utilizzato, verificate che l'argomento sia zero) + +Per chiamate di sistema più sofisticate che coinvolgono un numero più grande di +argomenti, il modo migliore è quello di incapsularne la maggior parte in una +struttura dati che verrà passata per puntatore. Questa struttura potrà +funzionare con future estensioni includendo un campo *size*:: + + struct xyzzy_params { + u32 size; /* userspace sets p->size = sizeof(struct xyzzy_params) */ + u32 param_1; + u64 param_2; + u64 param_3; + }; + +Fintanto che un qualsiasi campo nuovo, diciamo ``param_4``, è progettato per +offrire il comportamento precedente quando vale zero, allora questo permetterà +di gestire un conflitto di versione in entrambe le direzioni: + + - un vecchio kernel può gestire l'accesso di una versione moderna di un + programma in spazio utente verificando che la memoria oltre la dimensione + della struttura dati attesa sia zero (in pratica verificare che + ``param_4 == 0``). + - un nuovo kernel può gestire l'accesso di una versione vecchia di un + programma in spazio utente estendendo la struttura dati con zeri (in pratica + ``param_4 = 0``). + +Vedere :manpage:`perf_event_open(2)` e la funzione ``perf_copy_attr()`` (in +``kernel/events/core.c``) per un esempio pratico di questo approccio. + + +Progettare l'API: altre considerazioni +-------------------------------------- + +Se la vostra nuova chiamata di sistema permette allo spazio utente di fare +riferimento ad un oggetto del kernel, allora questa dovrebbe usare un +descrittore di file per accesso all'oggetto - non inventatevi nuovi tipi di +accesso da spazio utente quando il kernel ha già dei meccanismi e una semantica +ben definita per utilizzare i descrittori di file. + +Se la vostra nuova chiamata di sistema :manpage:`xyzzy(2)` ritorna un nuovo +descrittore di file, allora l'argomento *flags* dovrebbe includere un valore +equivalente a ``O_CLOEXEC`` per i nuovi descrittori. Questo rende possibile, +nello spazio utente, la chiusura della finestra temporale fra le chiamate a +``xyzzy()`` e ``fcntl(fd, F_SETFD, FD_CLOEXEC)``, dove un inaspettato +``fork()`` o ``execve()`` potrebbe trasferire il descrittore al programma +eseguito (Comunque, resistete alla tentazione di riutilizzare il valore di +``O_CLOEXEC`` dato che è specifico dell'architettura e fa parte di una +enumerazione di flag ``O_*`` che è abbastanza ricca). + +Se la vostra nuova chiamata di sistema ritorna un nuovo descrittore di file, +dovreste considerare che significato avrà l'uso delle chiamate di sistema +della famiglia di :manpage:`poll(2)`. Rendere un descrittore di file pronto +per la lettura o la scrittura è il tipico modo del kernel per notificare lo +spazio utente circa un evento associato all'oggetto del kernel. + +Se la vostra nuova chiamata di sistema :manpage:`xyzzy(2)` ha un argomento +che è il percorso ad un file:: + + int sys_xyzzy(const char __user *path, ..., unsigned int flags); + +dovreste anche considerare se non sia più appropriata una versione +:manpage:`xyzzyat(2)`:: + + int sys_xyzzyat(int dfd, const char __user *path, ..., unsigned int flags); + +Questo permette più flessibilità su come lo spazio utente specificherà il file +in questione; in particolare, permette allo spazio utente di richiedere la +funzionalità su un descrittore di file già aperto utilizzando il *flag* +``AT_EMPTY_PATH``, in pratica otterremmo gratuitamente l'operazione +:manpage:`fxyzzy(3)`:: + + - xyzzyat(AT_FDCWD, path, ..., 0) is equivalent to xyzzy(path,...) + - xyzzyat(fd, "", ..., AT_EMPTY_PATH) is equivalent to fxyzzy(fd, ...) + +(Per maggiori dettagli sulla logica delle chiamate \*at(), leggete la pagina +man :manpage:`openat(2)`; per un esempio di AT_EMPTY_PATH, leggere la pagina +man :manpage:`fstatat(2)`). + +Se la vostra nuova chiamata di sistema :manpage:`xyzzy(2)` prevede un parametro +per descrivere uno scostamento all'interno di un file, usate ``loff_t`` come +tipo cosicché scostamenti a 64-bit potranno essere supportati anche su +architetture a 32-bit. + +Se la vostra nuova chiamata di sistema :manpage:`xyzzy(2)` prevede l'uso di +funzioni riservate, allora dev'essere gestita da un opportuno bit di privilegio +(verificato con una chiamata a ``capable()``), come descritto nella pagina man +:manpage:`capabilities(7)`. Scegliete un bit di privilegio già esistente per +gestire la funzionalità associata, ma evitate la combinazione di diverse +funzionalità vagamente collegate dietro lo stesso bit, in quanto va contro il +principio di *capabilities* di separare i poteri di root. In particolare, +evitate di aggiungere nuovi usi al fin-troppo-generico privilegio +``CAP_SYS_ADMIN``. + +Se la vostra nuova chiamata di sistema :manpage:`xyzzy(2)` manipola altri +processi oltre a quello chiamato, allora dovrebbe essere limitata (usando +la chiamata ``ptrace_may_access()``) di modo che solo un processo chiamante +con gli stessi permessi del processo in oggetto, o con i necessari privilegi, +possa manipolarlo. + +Infine, state attenti che in alcune architetture non-x86 la vita delle chiamate +di sistema con argomenti a 64-bit viene semplificata se questi argomenti +ricadono in posizioni dispari (pratica, i parametri 1, 3, 5); questo permette +l'uso di coppie contigue di registri a 32-bit. (Questo non conta se gli +argomenti sono parte di una struttura dati che viene passata per puntatore). + + +Proporre l'API +-------------- + +Al fine di rendere le nuove chiamate di sistema di facile revisione, è meglio +che dividiate le modifiche i pezzi separati. Questi dovrebbero includere +almeno le seguenti voci in *commit* distinti (ognuno dei quali sarà descritto +più avanti): + + - l'essenza dell'implementazione della chiamata di sistema, con i prototipi, + i numeri generici, le modifiche al Kconfig e l'implementazione *stub* di + ripiego. + - preparare la nuova chiamata di sistema per un'architettura specifica, + solitamente x86 (ovvero tutti: x86_64, x86_32 e x32). + - un programma di auto-verifica da mettere in ``tools/testing/selftests/`` + che mostri l'uso della chiamata di sistema. + - una bozza di pagina man per la nuova chiamata di sistema. Può essere + scritta nell'email di presentazione, oppure come modifica vera e propria + al repositorio delle pagine man. + +Le proposte di nuove chiamate di sistema, come ogni altro modifica all'API del +kernel, deve essere sottomessa alla lista di discussione +linux-api@vger.kernel.org. + + +Implementazione di chiamate di sistema generiche +------------------------------------------------ + +Il principale punto d'accesso alla vostra nuova chiamata di sistema +:manpage:`xyzzy(2)` verrà chiamato ``sys_xyzzy()``; ma, piuttosto che in modo +esplicito, lo aggiungerete tramite la macro ``SYSCALL_DEFINEn``. La 'n' +indica il numero di argomenti della chiamata di sistema; la macro ha come +argomento il nome della chiamata di sistema, seguito dalle coppie (tipo, nome) +per definire i suoi parametri. L'uso di questa macro permette di avere +i metadati della nuova chiamata di sistema disponibili anche per altri +strumenti. + +Il nuovo punto d'accesso necessita anche del suo prototipo di funzione in +``include/linux/syscalls.h``, marcato come asmlinkage di modo da abbinargli +il modo in cui quelle chiamate di sistema verranno invocate:: + + asmlinkage long sys_xyzzy(...); + +Alcune architetture (per esempio x86) hanno le loro specifiche tabelle di +chiamate di sistema (syscall), ma molte altre architetture condividono una +tabella comune di syscall. Aggiungete alla lista generica la vostra nuova +chiamata di sistema aggiungendo un nuovo elemento alla lista in +``include/uapi/asm-generic/unistd.h``:: + + #define __NR_xyzzy 292 + __SYSCALL(__NR_xyzzy, sys_xyzzy) + +Aggiornate anche il contatore __NR_syscalls di modo che sia coerente con +l'aggiunta della nuove chiamate di sistema; va notato che se più di una nuova +chiamata di sistema viene aggiunga nella stessa finestra di sviluppo, il numero +della vostra nuova syscall potrebbe essere aggiustato al fine di risolvere i +conflitti. + +Il file ``kernel/sys_ni.c`` fornisce le implementazioni *stub* di ripiego che +ritornano ``-ENOSYS``. Aggiungete la vostra nuova chiamata di sistema anche +qui:: + + COND_SYSCALL(xyzzy); + +La vostra nuova funzionalità del kernel, e la chiamata di sistema che la +controlla, dovrebbero essere opzionali. Quindi, aggiungete un'opzione +``CONFIG`` (solitamente in ``init/Kconfig``). Come al solito per le nuove +opzioni ``CONFIG``: + + - Includete una descrizione della nuova funzionalità e della chiamata di + sistema che la controlla. + - Rendete l'opzione dipendente da EXPERT se dev'essere nascosta agli utenti + normali. + - Nel Makefile, rendere tutti i nuovi file sorgenti, che implementano la + nuova funzionalità, dipendenti dall'opzione CONFIG (per esempio + ``obj-$(CONFIG_XYZZY_SYSCALL) += xyzzy.o``). + - Controllate due volte che sia possibile generare il kernel con la nuova + opzione CONFIG disabilitata. + +Per riassumere, vi serve un *commit* che includa: + + - un'opzione ``CONFIG``per la nuova funzione, normalmente in ``init/Kconfig`` + - ``SYSCALL_DEFINEn(xyzzy, ...)`` per il punto d'accesso + - il corrispondente prototipo in ``include/linux/syscalls.h`` + - un elemento nella tabella generica in ``include/uapi/asm-generic/unistd.h`` + - *stub* di ripiego in ``kernel/sys_ni.c`` + + +Implementazione delle chiamate di sistema x86 +--------------------------------------------- + +Per collegare la vostra nuova chiamate di sistema alle piattaforme x86, +dovete aggiornate la tabella principale di syscall. Assumendo che la vostra +nuova chiamata di sistema non sia particolarmente speciale (vedere sotto), +dovete aggiungere un elemento *common* (per x86_64 e x32) in +arch/x86/entry/syscalls/syscall_64.tbl:: + + 333 common xyzzy sys_xyzzy + +e un elemento per *i386* ``arch/x86/entry/syscalls/syscall_32.tbl``:: + + 380 i386 xyzzy sys_xyzzy + +Ancora una volta, questi numeri potrebbero essere cambiati se generano +conflitti durante la finestra di integrazione. + + +Chiamate di sistema compatibili (generico) +------------------------------------------ + +Per molte chiamate di sistema, la stessa implementazione a 64-bit può essere +invocata anche quando il programma in spazio utente è a 32-bit; anche se la +chiamata di sistema include esplicitamente un puntatore, questo viene gestito +in modo trasparente. + +Tuttavia, ci sono un paio di situazione dove diventa necessario avere un +livello di gestione della compatibilità per risolvere le differenze di +dimensioni fra 32-bit e 64-bit. + +Il primo caso è quando un kernel a 64-bit supporta anche programmi in spazio +utente a 32-bit, perciò dovrà ispezionare aree della memoria (``__user``) che +potrebbero contenere valori a 32-bit o a 64-bit. In particolar modo, questo +è necessario quando un argomento di una chiamata di sistema è: + + - un puntatore ad un puntatore + - un puntatore ad una struttura dati contenente a sua volta un puntatore + ( ad esempio ``struct iovec __user *``) + - un puntatore ad un tipo intero di dimensione variabile (``time_t``, + ``off_t``, ``long``, ...) + - un puntatore ad una struttura dati contenente un tipo intero di dimensione + variabile. + +Il secondo caso che richiede un livello di gestione della compatibilità è +quando uno degli argomenti di una chiamata a sistema è esplicitamente un tipo +a 64-bit anche su architetture a 32-bit, per esempio ``loff_t`` o ``__u64``. +In questo caso, un valore che arriva ad un kernel a 64-bit da un'applicazione +a 32-bit verrà diviso in due valori a 32-bit che dovranno essere riassemblati +in questo livello di compatibilità. + +(Da notare che non serve questo livello di compatibilità per argomenti che +sono puntatori ad un tipo esplicitamente a 64-bit; per esempio, in +:manpage:`splice(2)` l'argomento di tipo ``loff_t __user *`` non necessita +di una chiamata di sistema ``compat_``) + +La versione compatibile della nostra chiamata di sistema si chiamerà +``compat_sys_xyzzy()``, e viene aggiunta utilizzando la macro +``COMPAT_SYSCALL_DEFINEn()`` (simile a SYSCALL_DEFINEn). Questa versione +dell'implementazione è parte del kernel a 64-bit ma accetta parametri a 32-bit +che trasformerà secondo le necessità (tipicamente, la versione +``compat_sys_`` converte questi valori nello loro corrispondente a 64-bit e +può chiamare la versione ``sys_`` oppure invocare una funzione che implementa +le parti comuni). + +Il punto d'accesso *compat* deve avere il corrispondente prototipo di funzione +in ``include/linux/compat.h``, marcato come asmlinkage di modo da abbinargli +il modo in cui quelle chiamate di sistema verranno invocate:: + + asmlinkage long compat_sys_xyzzy(...); + +Se la chiamata di sistema prevede una struttura dati organizzata in modo +diverso per sistemi a 32-bit e per quelli a 64-bit, diciamo +``struct xyzzy_args``, allora il file d'intestazione +``then the include/linux/compat.h`` deve includere la sua versione +*compatibile* (``struct compat_xyzzy_args``); ogni variabile con +dimensione variabile deve avere il proprio tipo ``compat_`` corrispondente +a quello in ``struct xyzzy_args``. La funzione ``compat_sys_xyzzy()`` +può usare la struttura ``compat_`` per analizzare gli argomenti ricevuti +da una chiamata a 32-bit. + +Per esempio, se avete i seguenti campi:: + + struct xyzzy_args { + const char __user *ptr; + __kernel_long_t varying_val; + u64 fixed_val; + /* ... */ + }; + +nella struttura ``struct xyzzy_args``, allora la struttura +``struct compat_xyzzy_args`` dovrebbe avere:: + + struct compat_xyzzy_args { + compat_uptr_t ptr; + compat_long_t varying_val; + u64 fixed_val; + /* ... */ + }; + +La lista generica delle chiamate di sistema ha bisogno di essere +aggiustata al fine di permettere l'uso della versione *compatibile*; +la voce in ``include/uapi/asm-generic/unistd.h`` dovrebbero usare +``__SC_COMP`` piuttosto di ``__SYSCALL``:: + + #define __NR_xyzzy 292 + __SC_COMP(__NR_xyzzy, sys_xyzzy, compat_sys_xyzzy) + +Riassumendo, vi serve: + + - un ``COMPAT_SYSCALL_DEFINEn(xyzzy, ...)`` per il punto d'accesso + *compatibile* + - un prototipo in ``include/linux/compat.h`` + - (se necessario) una struttura di compatibilità a 32-bit in + ``include/linux/compat.h`` + - una voce ``__SC_COMP``, e non ``__SYSCALL``, in + ``include/uapi/asm-generic/unistd.h`` + +Compatibilità delle chiamate di sistema (x86) +--------------------------------------------- + +Per collegare una chiamata di sistema, su un'architettura x86, con la sua +versione *compatibile*, è necessario aggiustare la voce nella tabella +delle syscall. + +Per prima cosa, la voce in ``arch/x86/entry/syscalls/syscall_32.tbl`` prende +un argomento aggiuntivo per indicare che un programma in spazio utente +a 32-bit, eseguito su un kernel a 64-bit, dovrebbe accedere tramite il punto +d'accesso compatibile:: + + 380 i386 xyzzy sys_xyzzy __ia32_compat_sys_xyzzy + +Secondo, dovete capire cosa dovrebbe succedere alla nuova chiamata di sistema +per la versione dell'ABI x32. Qui C'è una scelta da fare: gli argomenti +possono corrisponde alla versione a 64-bit o a quella a 32-bit. + +Se c'è un puntatore ad un puntatore, la decisione è semplice: x32 è ILP32, +quindi gli argomenti dovrebbero corrispondere a quelli a 32-bit, e la voce in +``arch/x86/entry/syscalls/syscall_64.tbl`` sarà divisa cosicché i programmi +x32 eseguano la chiamata *compatibile*:: + + 333 64 xyzzy sys_xyzzy + ... + 555 x32 xyzzy __x32_compat_sys_xyzzy + +Se non ci sono puntatori, allora è preferibile riutilizzare la chiamata di +sistema a 64-bit per l'ABI x32 (e di conseguenza la voce in +arch/x86/entry/syscalls/syscall_64.tbl rimane immutata). + +In ambo i casi, dovreste verificare che i tipi usati dagli argomenti +abbiano un'esatta corrispondenza da x32 (-mx32) al loro equivalente a +32-bit (-m32) o 64-bit (-m64). + + +Chiamate di sistema che ritornano altrove +----------------------------------------- + +Nella maggior parte delle chiamate di sistema, al termine della loro +esecuzione, i programmi in spazio utente riprendono esattamente dal punto +in cui si erano interrotti -- quindi dall'istruzione successiva, con lo +stesso *stack* e con la maggior parte del registri com'erano stati +lasciati prima della chiamata di sistema, e anche con la stessa memoria +virtuale. + +Tuttavia, alcune chiamata di sistema fanno le cose in modo differente. +Potrebbero ritornare ad un punto diverso (``rt_sigreturn``) o cambiare +la memoria in spazio utente (``fork``/``vfork``/``clone``) o perfino +l'architettura del programma (``execve``/``execveat``). + +Per permettere tutto ciò, l'implementazione nel kernel di questo tipo di +chiamate di sistema potrebbero dover salvare e ripristinare registri +aggiuntivi nello *stack* del kernel, permettendo così un controllo completo +su dove e come l'esecuzione dovrà continuare dopo l'esecuzione della +chiamata di sistema. + +Queste saranno specifiche per ogni architettura, ma tipicamente si definiscono +dei punti d'accesso in *assembly* per salvare/ripristinare i registri +aggiuntivi e quindi chiamare il vero punto d'accesso per la chiamata di +sistema. + +Per l'architettura x86_64, questo è implementato come un punto d'accesso +``stub_xyzzy`` in ``arch/x86/entry/entry_64.S``, e la voce nella tabella +di syscall (``arch/x86/entry/syscalls/syscall_64.tbl``) verrà corretta di +conseguenza:: + + 333 common xyzzy stub_xyzzy + +L'equivalente per programmi a 32-bit eseguiti su un kernel a 64-bit viene +normalmente chiamato ``stub32_xyzzy`` e implementato in +``arch/x86/entry/entry_64_compat.S`` con la corrispondente voce nella tabella +di syscall ``arch/x86/entry/syscalls/syscall_32.tbl`` corretta nel +seguente modo:: + + 380 i386 xyzzy sys_xyzzy stub32_xyzzy + +Se una chiamata di sistema necessita di un livello di compatibilità (come +nella sezione precedente), allora la versione ``stub32_`` deve invocare +la versione ``compat_sys_`` piuttosto che quella nativa a 64-bit. In aggiunta, +se l'implementazione dell'ABI x32 è diversa da quella x86_64, allora la sua +voce nella tabella di syscall dovrà chiamare uno *stub* che invoca la versione +``compat_sys_``, + +Per completezza, sarebbe carino impostare una mappatura cosicché +*user-mode* Linux (UML) continui a funzionare -- la sua tabella di syscall +farà riferimento a stub_xyzzy, ma UML non include l'implementazione +in ``arch/x86/entry/entry_64.S`` (perché UML simula i registri eccetera). +Correggerlo è semplice, basta aggiungere una #define in +``arch/x86/um/sys_call_table_64.c``:: + + #define stub_xyzzy sys_xyzzy + + +Altri dettagli +-------------- + +La maggior parte dei kernel tratta le chiamate di sistema allo stesso modo, +ma possono esserci rare eccezioni per le quali potrebbe essere necessario +l'aggiornamento della vostra chiamata di sistema. + +Il sotto-sistema di controllo (*audit subsystem*) è uno di questi casi +speciali; esso include (per architettura) funzioni che classificano alcuni +tipi di chiamate di sistema -- in particolare apertura dei file +(``open``/``openat``), esecuzione dei programmi (``execve``/``exeveat``) +oppure multiplatori di socket (``socketcall``). Se la vostra nuova chiamata +di sistema è simile ad una di queste, allora il sistema di controllo dovrebbe +essere aggiornato. + +Più in generale, se esiste una chiamata di sistema che è simile alla vostra, +vale la pena fare una ricerca con ``grep`` su tutto il kernel per la chiamata +di sistema esistente per verificare che non ci siano altri casi speciali. + + +Verifica +-------- + +Una nuova chiamata di sistema dev'essere, ovviamente, provata; è utile fornire +ai revisori un programma in spazio utente che mostri l'uso della chiamata di +sistema. Un buon modo per combinare queste cose è quello di aggiungere un +semplice programma di auto-verifica in una nuova cartella in +``tools/testing/selftests/``. + +Per una nuova chiamata di sistema, ovviamente, non ci sarà alcuna funzione +in libc e quindi il programma di verifica dovrà invocarla usando ``syscall()``; +inoltre, se la nuova chiamata di sistema prevede un nuova struttura dati +visibile in spazio utente, il file d'intestazione necessario dev'essere +installato al fine di compilare il programma. + +Assicuratevi che il programma di auto-verifica possa essere eseguito +correttamente su tutte le architetture supportate. Per esempio, verificate che +funzioni quando viene compilato per x86_64 (-m64), x86_32 (-m32) e x32 (-mx32). + +Al fine di una più meticolosa ed estesa verifica della nuova funzionalità, +dovreste considerare l'aggiunta di nuove verifica al progetto 'Linux Test', +oppure al progetto xfstests per cambiamenti relativi al filesystem. + + - https://linux-test-project.github.io/ + - git://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git + + +Pagine man +---------- + +Tutte le nuove chiamate di sistema dovrebbero avere una pagina man completa, +idealmente usando i marcatori groff, ma anche il puro testo può andare. Se +state usando groff, è utile che includiate nella email di presentazione una +versione già convertita in formato ASCII: semplificherà la vita dei revisori. + +Le pagine man dovrebbero essere in copia-conoscenza verso +linux-man@vger.kernel.org +Per maggiori dettagli, leggere +https://www.kernel.org/doc/man-pages/patches.html + + +Non invocate chiamate di sistema dal kernel +------------------------------------------- + +Le chiamate di sistema sono, come già detto prima, punti di interazione fra +lo spazio utente e il kernel. Perciò, le chiamate di sistema come +``sys_xyzzy()`` o ``compat_sys_xyzzy()`` dovrebbero essere chiamate solo dallo +spazio utente attraverso la tabella syscall, ma non da nessun altro punto nel +kernel. Se la nuova funzionalità è utile all'interno del kernel, per esempio +dev'essere condivisa fra una vecchia e una nuova chiamata di sistema o +dev'essere utilizzata da una chiamata di sistema e la sua variante compatibile, +allora dev'essere implementata come una funzione di supporto +(*helper function*) (per esempio ``kern_xyzzy()``). Questa funzione potrà +essere chiamata dallo *stub* (``sys_xyzzy()``), dalla variante compatibile +(``compat_sys_xyzzy()``), e/o da altri parti del kernel. + +Sui sistemi x86 a 64-bit, a partire dalla versione v4.17 è un requisito +fondamentale quello di non invocare chiamate di sistema all'interno del kernel. +Esso usa una diversa convenzione per l'invocazione di chiamate di sistema dove +``struct pt_regs`` viene decodificata al volo in una funzione che racchiude +la chiamata di sistema la quale verrà eseguita successivamente. +Questo significa che verranno passati solo i parametri che sono davvero +necessari ad una specifica chiamata di sistema, invece che riempire ogni volta +6 registri del processore con contenuti presi dallo spazio utente (potrebbe +causare seri problemi nella sequenza di chiamate). + +Inoltre, le regole su come i dati possano essere usati potrebbero differire +fra il kernel e l'utente. Questo è un altro motivo per cui invocare +``sys_xyzzy()`` è generalmente una brutta idea. + +Eccezioni a questa regola vengono accettate solo per funzioni d'architetture +che surclassano quelle generiche, per funzioni d'architettura di compatibilità, +o per altro codice in arch/ + + +Riferimenti e fonti +------------------- + + - Articolo di Michael Kerris su LWN sull'uso dell'argomento flags nelle + chiamate di sistema: https://lwn.net/Articles/585415/ + - Articolo di Michael Kerris su LWN su come gestire flag sconosciuti in + una chiamata di sistema: https://lwn.net/Articles/588444/ + - Articolo di Jake Edge su LWN che descrive i limiti degli argomenti a 64-bit + delle chiamate di sistema: https://lwn.net/Articles/311630/ + - Una coppia di articoli di David Drysdale che descrivono i dettagli del + percorso implementativo di una chiamata di sistema per la versione v3.14: + + - https://lwn.net/Articles/604287/ + - https://lwn.net/Articles/604515/ + + - Requisiti specifici alle architetture sono discussi nella pagina man + :manpage:`syscall(2)` : + http://man7.org/linux/man-pages/man2/syscall.2.html#NOTES + - Collezione di email di Linux Torvalds sui problemi relativi a ``ioctl()``: + http://yarchive.net/comp/linux/ioctl.html + - "Come non inventare interfacce del kernel", Arnd Bergmann, + http://www.ukuug.org/events/linux2007/2007/papers/Bergmann.pdf + - Articolo di Michael Kerris su LWN sull'evitare nuovi usi di CAP_SYS_ADMIN: + https://lwn.net/Articles/486306/ + - Raccomandazioni da Andrew Morton circa il fatto che tutte le informazioni + su una nuova chiamata di sistema dovrebbero essere contenute nello stesso + filone di discussione di email: https://lkml.org/lkml/2014/7/24/641 + - Raccomandazioni da Michael Kerrisk circa il fatto che le nuove chiamate di + sistema dovrebbero avere una pagina man: https://lkml.org/lkml/2014/6/13/309 + - Consigli da Thomas Gleixner sul fatto che il collegamento all'architettura + x86 dovrebbe avvenire in un *commit* differente: + https://lkml.org/lkml/2014/11/19/254 + - Consigli da Greg Kroah-Hartman circa la bontà d'avere una pagina man e un + programma di auto-verifica per le nuove chiamate di sistema: + https://lkml.org/lkml/2014/3/19/710 + - Discussione di Michael Kerrisk sulle nuove chiamate di sistema contro + le estensioni :manpage:`prctl(2)`: https://lkml.org/lkml/2014/6/3/411 + - Consigli da Ingo Molnar che le chiamate di sistema con più argomenti + dovrebbero incapsularli in una struttura che includa un argomento + *size* per garantire l'estensibilità futura: + https://lkml.org/lkml/2015/7/30/117 + - Un certo numero di casi strani emersi dall'uso (riuso) dei flag O_*: + + - commit 75069f2b5bfb ("vfs: renumber FMODE_NONOTIFY and add to uniqueness + check") + - commit 12ed2e36c98a ("fanotify: FMODE_NONOTIFY and __O_SYNC in sparc + conflict") + - commit bb458c644a59 ("Safer ABI for O_TMPFILE") + + - Discussion from Matthew Wilcox about restrictions on 64-bit arguments: + https://lkml.org/lkml/2008/12/12/187 + - Raccomandazioni da Greg Kroah-Hartman sul fatto che i flag sconosciuti dovrebbero + essere controllati: https://lkml.org/lkml/2014/7/17/577 + - Raccomandazioni da Linus Torvalds che le chiamate di sistema x32 dovrebbero + favorire la compatibilità con le versioni a 64-bit piuttosto che quelle a 32-bit: + https://lkml.org/lkml/2011/8/31/244 diff --git a/Documentation/translations/it_IT/process/applying-patches.rst b/Documentation/translations/it_IT/process/applying-patches.rst new file mode 100644 index 000000000000..f5e9c7d0b16d --- /dev/null +++ b/Documentation/translations/it_IT/process/applying-patches.rst @@ -0,0 +1,13 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/applying-patches.rst <applying_patches>` + + +.. _it_applying_patches: + +Applicare modifiche al kernel Linux +=================================== + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/changes.rst b/Documentation/translations/it_IT/process/changes.rst new file mode 100644 index 000000000000..956cf95a1214 --- /dev/null +++ b/Documentation/translations/it_IT/process/changes.rst @@ -0,0 +1,12 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/changes.rst <changes>` + +.. _it_changes: + +Requisiti minimi per compilare il kernel +++++++++++++++++++++++++++++++++++++++++ + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/clang-format.rst b/Documentation/translations/it_IT/process/clang-format.rst new file mode 100644 index 000000000000..77eac809a639 --- /dev/null +++ b/Documentation/translations/it_IT/process/clang-format.rst @@ -0,0 +1,197 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/clang-format.rst <clangformat>` +:Translator: Federico Vaga <federico.vaga@vaga.pv.it> + +.. _it_clangformat: + +clang-format +============ +``clang-format`` è uno strumento per formattare codice C/C++/... secondo +un gruppo di regole ed euristiche. Come tutti gli strumenti, non è perfetto +e non copre tutti i singoli casi, ma è abbastanza buono per essere utile. + +``clang-format`` può essere usato per diversi fini: + + - Per riformattare rapidamente un blocco di codice secondo lo stile del + kernel. Particolarmente utile quando si sposta del codice e lo si + allinea/ordina. Vedere it_clangformatreformat_. + + - Identificare errori di stile, refusi e possibili miglioramenti nei + file che mantieni, le modifiche che revisioni, le differenze, + eccetera. Vedere it_clangformatreview_. + + - Ti aiuta a seguire lo stile del codice, particolarmente utile per i + nuovi arrivati o per coloro che lavorano allo stesso tempo su diversi + progetti con stili di codifica differenti. + +Il suo file di configurazione è ``.clang-format`` e si trova nella cartella +principale dei sorgenti del kernel. Le regole scritte in quel file tentano +di approssimare le lo stile di codifica del kernel. Si tenta anche di seguire +il più possibile +:ref:`Documentation/translations/it_IT/process/coding-style.rst <it_codingstyle>`. +Dato che non tutto il kernel segue lo stesso stile, potreste voler aggiustare +le regole di base per un particolare sottosistema o cartella. Per farlo, +potete sovrascriverle scrivendole in un altro file ``.clang-format`` in +una sottocartella. + +Questo strumento è già stato incluso da molto tempo nelle distribuzioni +Linux più popolari. Cercate ``clang-format`` nel vostro repositorio. +Altrimenti, potete scaricare una versione pre-generata dei binari di LLVM/clang +oppure generarlo dai codici sorgenti: + + http://releases.llvm.org/download.html + +Troverete più informazioni ai seguenti indirizzi: + + https://clang.llvm.org/docs/ClangFormat.html + + https://clang.llvm.org/docs/ClangFormatStyleOptions.html + + +.. _it_clangformatreview: + +Revisionare lo stile di codifica per file e modifiche +----------------------------------------------------- + +Eseguendo questo programma, potrete revisionare un intero sottosistema, +cartella o singoli file alla ricerca di errori di stile, refusi o +miglioramenti. + +Per farlo, potete eseguire qualcosa del genere:: + + # Make sure your working directory is clean! + clang-format -i kernel/*.[ch] + +E poi date un'occhiata a *git diff*. + +Osservare le righe di questo diff è utile a migliorare/aggiustare +le opzioni di stile nel file di configurazione; così come per verificare +le nuove funzionalità/versioni di ``clang-format``. + +``clang-format`` è in grado di leggere diversi diff unificati, quindi +potrete revisionare facilmente delle modifiche e *git diff*. +La documentazione si trova al seguente indirizzo: + + https://clang.llvm.org/docs/ClangFormat.html#script-for-patch-reformatting + +Per evitare che ``clang-format`` formatti alcune parti di un file, potete +scrivere nel codice:: + + int formatted_code; + // clang-format off + void unformatted_code ; + // clang-format on + void formatted_code_again; + +Nonostante si attraente l'idea di utilizzarlo per mantenere un file +sempre in sintonia con ``clang-format``, specialmente per file nuovi o +se siete un manutentore, ricordatevi che altre persone potrebbero usare +una versione diversa di ``clang-format`` oppure non utilizzarlo del tutto. +Quindi, dovreste trattenervi dall'usare questi marcatori nel codice del +kernel; almeno finché non vediamo che ``clang-format`` è diventato largamente +utilizzato. + + +.. _it_clangformatreformat: + +Riformattare blocchi di codice +------------------------------ + +Utilizzando dei plugin per il vostro editor, potete riformattare una +blocco (selezione) di codice con una singola combinazione di tasti. +Questo è particolarmente utile: quando si riorganizza il codice, per codice +complesso, macro multi-riga (e allineare le loro "barre"), eccetera. + +Ricordatevi che potete sempre aggiustare le modifiche in quei casi dove +questo strumento non ha fatto un buon lavoro. Ma come prima approssimazione, +può essere davvero molto utile. + +Questo programma si integra con molti dei più popolari editor. Alcuni di +essi come vim, emacs, BBEdit, Visaul Studio, lo supportano direttamente. +Al seguente indirizzo troverete le istruzioni: + + https://clang.llvm.org/docs/ClangFormat.html + +Per Atom, Eclipse, Sublime Text, Visual Studio Code, XCode e altri editor +e IDEs dovreste essere in grado di trovare dei plugin pronti all'uso. + +Per questo caso d'uso, considerate l'uso di un secondo ``.clang-format`` +che potete personalizzare con le vostre opzioni. +Consultare it_clangformatextra_. + + +.. _it_clangformatmissing: + +Cose non supportate +------------------- + +``clang-format`` non ha il supporto per alcune cose che sono comuni nel +codice del kernel. Sono facili da ricordare; quindi, se lo usate +regolarmente, imparerete rapidamente a evitare/ignorare certi problemi. + +In particolare, quelli più comuni che noterete sono: + + - Allineamento di ``#define`` su una singola riga, per esempio:: + + #define TRACING_MAP_BITS_DEFAULT 11 + #define TRACING_MAP_BITS_MAX 17 + #define TRACING_MAP_BITS_MIN 7 + + contro:: + + #define TRACING_MAP_BITS_DEFAULT 11 + #define TRACING_MAP_BITS_MAX 17 + #define TRACING_MAP_BITS_MIN 7 + + - Allineamento dei valori iniziali, per esempio:: + + static const struct file_operations uprobe_events_ops = { + .owner = THIS_MODULE, + .open = probes_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, + .write = probes_write, + }; + + contro:: + + static const struct file_operations uprobe_events_ops = { + .owner = THIS_MODULE, + .open = probes_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, + .write = probes_write, + }; + + +.. _it_clangformatextra: + +Funzionalità e opzioni aggiuntive +--------------------------------- + +Al fine di minimizzare le differenze fra il codice attuale e l'output +del programma, alcune opzioni di stile e funzionalità non sono abilitate +nella configurazione base. In altre parole, lo scopo è di rendere le +differenze le più piccole possibili, permettendo la semplificazione +della revisione di file, differenze e modifiche. + +In altri casi (per esempio un particolare sottosistema/cartella/file), lo +stile del kernel potrebbe essere diverso e abilitare alcune di queste +opzioni potrebbe dare risultati migliori. + +Per esempio: + + - Allineare assegnamenti (``AlignConsecutiveAssignments``). + + - Allineare dichiarazioni (``AlignConsecutiveDeclarations``). + + - Riorganizzare il testo nei commenti (``ReflowComments``). + + - Ordinare gli ``#include`` (``SortIncludes``). + +Piuttosto che per interi file, solitamente sono utili per la riformattazione +di singoli blocchi. In alternativa, potete creare un altro file +``.clang-format`` da utilizzare con il vostro editor/IDE. diff --git a/Documentation/translations/it_IT/process/code-of-conduct.rst b/Documentation/translations/it_IT/process/code-of-conduct.rst new file mode 100644 index 000000000000..7dbd7f55f37c --- /dev/null +++ b/Documentation/translations/it_IT/process/code-of-conduct.rst @@ -0,0 +1,12 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/code-of-conduct.rst <code_of_conduct>` + +.. _it_code_of_conduct: + +Accordo dei contributori sul codice di condotta ++++++++++++++++++++++++++++++++++++++++++++++++ + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/coding-style.rst b/Documentation/translations/it_IT/process/coding-style.rst new file mode 100644 index 000000000000..b707bdbe178c --- /dev/null +++ b/Documentation/translations/it_IT/process/coding-style.rst @@ -0,0 +1,1094 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/coding-style.rst <codingstyle>` +:Translator: Federico Vaga <federico.vaga@vaga.pv.it> + +.. _it_codingstyle: + +Stile del codice per il kernel Linux +==================================== + +Questo è un breve documento che descrive lo stile di codice preferito per +il kernel Linux. Lo stile di codifica è molto personale e non voglio +**forzare** nessuno ad accettare il mio, ma questo stile è quello che +dev'essere usato per qualsiasi cosa che io sia in grado di mantenere, e l'ho +preferito anche per molte altre cose. Per favore, almeno tenete in +considerazione le osservazioni espresse qui. + +La prima cosa che suggerisco è quella di stamparsi una copia degli standard +di codifica GNU e di NON leggerla. Bruciatela, è un grande gesto simbolico. + +Comunque, ecco i punti: + +1) Indentazione +--------------- + +La tabulazione (tab) è di 8 caratteri e così anche le indentazioni. Ci sono +alcuni movimenti di eretici che vorrebbero l'indentazione a 4 (o perfino 2!) +caratteri di profondità, che è simile al tentativo di definire il valore del +pi-greco a 3. + +Motivazione: l'idea dell'indentazione è di definire chiaramente dove un blocco +di controllo inizia e finisce. Specialmente quando siete rimasti a guardare lo +schermo per 20 ore a file, troverete molto più facile capire i livelli di +indentazione se questi sono larghi. + +Ora, alcuni rivendicano che un'indentazione da 8 caratteri sposta il codice +troppo a destra e che quindi rende difficile la lettura su schermi a 80 +caratteri. La risposta a questa affermazione è che se vi servono più di 3 +livelli di indentazione, siete comunque fregati e dovreste correggere il vostro +programma. + +In breve, l'indentazione ad 8 caratteri rende più facile la lettura, e in +aggiunta vi avvisa quando state annidando troppo le vostre funzioni. +Tenete ben a mente questo avviso. + +Al fine di facilitare l'indentazione del costrutto switch, si preferisce +allineare sulla stessa colonna la parola chiave ``switch`` e i suoi +subordinati ``case``. In questo modo si evita una doppia indentazione per +i ``case``. Un esempio.: + +.. code-block:: c + + switch (suffix) { + case 'G': + case 'g': + mem <<= 30; + break; + case 'M': + case 'm': + mem <<= 20; + break; + case 'K': + case 'k': + mem <<= 10; + /* fall through */ + default: + break; + } + +A meno che non vogliate nascondere qualcosa, non mettete più istruzioni sulla +stessa riga: + +.. code-block:: c + + if (condition) do_this; + do_something_everytime; + +né mettete più assegnamenti sulla stessa riga. Lo stile del kernel +è ultrasemplice. Evitate espressioni intricate. + +Al di fuori dei commenti, della documentazione ed escludendo i Kconfig, gli +spazi non vengono mai usati per l'indentazione, e l'esempio qui sopra è +volutamente errato. + +Procuratevi un buon editor di testo e non lasciate spazi bianchi alla fine +delle righe. + + +2) Spezzare righe lunghe e stringhe +----------------------------------- + +Lo stile del codice riguarda la leggibilità e la manutenibilità utilizzando +strumenti comuni. + +Il limite delle righe è di 80 colonne e questo e un limite fortemente +desiderato. + +Espressioni più lunghe di 80 colonne saranno spezzettate in pezzi più piccoli, +a meno che eccedere le 80 colonne non aiuti ad aumentare la leggibilità senza +nascondere informazioni. I pezzi derivati sono sostanzialmente più corti degli +originali e vengono posizionati più a destra. Lo stesso si applica, nei file +d'intestazione, alle funzioni con una lista di argomenti molto lunga. Tuttavia, +non spezzettate mai le stringhe visibili agli utenti come i messaggi di +printk, questo perché inibireste la possibilità d'utilizzare grep per cercarle. + +3) Posizionamento di parentesi graffe e spazi +--------------------------------------------- + +Un altro problema che s'affronta sempre quando si parla di stile in C è +il posizionamento delle parentesi graffe. Al contrario della dimensione +dell'indentazione, non ci sono motivi tecnici sulla base dei quali scegliere +una strategia di posizionamento o un'altra; ma il modo qui preferito, +come mostratoci dai profeti Kernighan e Ritchie, è quello di +posizionare la parentesi graffa di apertura per ultima sulla riga, e quella +di chiusura per prima su una nuova riga, così: + +.. code-block:: c + + if (x is true) { + we do y + } + +Questo è valido per tutte le espressioni che non siano funzioni (if, switch, +for, while, do). Per esempio: + +.. code-block:: c + + switch (action) { + case KOBJ_ADD: + return "add"; + case KOBJ_REMOVE: + return "remove"; + case KOBJ_CHANGE: + return "change"; + default: + return NULL; + } + +Tuttavia, c'è il caso speciale, le funzioni: queste hanno la parentesi graffa +di apertura all'inizio della riga successiva, quindi: + +.. code-block:: c + + int function(int x) + { + body of function + } + +Eretici da tutto il mondo affermano che questa incoerenza è ... +insomma ... incoerente, ma tutte le persone ragionevoli sanno che (a) +K&R hanno **ragione** e (b) K&R hanno ragione. A parte questo, le funzioni +sono comunque speciali (non potete annidarle in C). + +Notate che la graffa di chiusura è da sola su una riga propria, ad +**eccezione** di quei casi dove è seguita dalla continuazione della stessa +espressione, in pratica ``while`` nell'espressione do-while, oppure ``else`` +nell'espressione if-else, come questo: + +.. code-block:: c + + do { + body of do-loop + } while (condition); + +e + +.. code-block:: c + + if (x == y) { + .. + } else if (x > y) { + ... + } else { + .... + } + +Motivazione: K&R. + +Inoltre, notate che questo posizionamento delle graffe minimizza il numero +di righe vuote senza perdere di leggibilità. In questo modo, dato che le +righe sul vostro schermo non sono una risorsa illimitata (pensate ad uno +terminale con 25 righe), avrete delle righe vuote da riempire con dei +commenti. + +Non usate inutilmente le graffe dove una singola espressione è sufficiente. + +.. code-block:: c + + if (condition) + action(); + +e + +.. code-block:: none + + if (condition) + do_this(); + else + do_that(); + +Questo non vale nel caso in cui solo un ramo dell'espressione if-else +contiene una sola espressione; in quest'ultimo caso usate le graffe per +entrambe i rami: + +.. code-block:: c + + if (condition) { + do_this(); + do_that(); + } else { + otherwise(); + } + +Inoltre, usate le graffe se un ciclo contiene più di una semplice istruzione: + +.. code-block:: c + + while (condition) { + if (test) + do_something(); + } + +3.1) Spazi +********** + +Lo stile del kernel Linux per quanto riguarda gli spazi, dipende +(principalmente) dalle funzioni e dalle parole chiave. Usate una spazio dopo +(quasi tutte) le parole chiave. L'eccezioni più evidenti sono sizeof, typeof, +alignof, e __attribute__, il cui aspetto è molto simile a quello delle +funzioni (e in Linux, solitamente, sono usate con le parentesi, anche se il +linguaggio non lo richiede; come ``sizeof info`` dopo aver dichiarato +``struct fileinfo info``). + +Quindi utilizzate uno spazio dopo le seguenti parole chiave:: + + if, switch, case, for, do, while + +ma non con sizeof, typeof, alignof, o __attribute__. Ad esempio, + +.. code-block:: c + + + s = sizeof(struct file); + +Non aggiungete spazi attorno (dentro) ad un'espressione fra parentesi. Questo +esempio è **brutto**: + +.. code-block:: c + + + s = sizeof( struct file ); + +Quando dichiarate un puntatore ad una variabile o una funzione che ritorna un +puntatore, il posto suggerito per l'asterisco ``*`` è adiacente al nome della +variabile o della funzione, e non adiacente al nome del tipo. Esempi: + +.. code-block:: c + + + char *linux_banner; + unsigned long long memparse(char *ptr, char **retptr); + char *match_strdup(substring_t *s); + +Usate uno spazio attorno (da ogni parte) alla maggior parte degli operatori +binari o ternari, come i seguenti:: + + = + - < > * / % | & ^ <= >= == != ? : + +ma non mettete spazi dopo gli operatori unari:: + + & * + - ~ ! sizeof typeof alignof __attribute__ defined + +nessuno spazio dopo l'operatore unario suffisso di incremento o decremento:: + + ++ -- + +nessuno spazio dopo l'operatore unario prefisso di incremento o decremento:: + + ++ -- + +e nessuno spazio attorno agli operatori dei membri di una struttura ``.`` e +``->``. + +Non lasciate spazi bianchi alla fine delle righe. Alcuni editor con +l'indentazione ``furba`` inseriranno gli spazi bianchi all'inizio di una nuova +riga in modo appropriato, quindi potrete scrivere la riga di codice successiva +immediatamente. Tuttavia, alcuni di questi stessi editor non rimuovono +questi spazi bianchi quando non scrivete nulla sulla nuova riga, ad esempio +perché volete lasciare una riga vuota. Il risultato è che finirete per avere +delle righe che contengono spazi bianchi in coda. + +Git vi avviserà delle modifiche che aggiungono questi spazi vuoti di fine riga, +e può opzionalmente rimuoverli per conto vostro; tuttavia, se state applicando +una serie di modifiche, questo potrebbe far fallire delle modifiche successive +perché il contesto delle righe verrà cambiato. + +4) Assegnare nomi +----------------- + +C è un linguaggio spartano, e così dovrebbero esserlo i vostri nomi. Al +contrario dei programmatori Modula-2 o Pascal, i programmatori C non usano +nomi graziosi come ThisVariableIsATemporaryCounter. Un programmatore C +chiamerebbe questa variabile ``tmp``, che è molto più facile da scrivere e +non è una delle più difficili da capire. + +TUTTAVIA, nonostante i nomi con notazione mista siano da condannare, i nomi +descrittivi per variabili globali sono un dovere. Chiamare una funzione +globale ``pippo`` è un insulto. + +Le variabili GLOBALI (da usare solo se vi servono **davvero**) devono avere +dei nomi descrittivi, così come le funzioni globali. Se avete una funzione +che conta gli utenti attivi, dovreste chiamarla ``count_active_users()`` o +qualcosa di simile, **non** dovreste chiamarla ``cntusr()``. + +Codificare il tipo di funzione nel suo nome (quella cosa chiamata notazione +ungherese) fa male al cervello - il compilatore conosce comunque il tipo e +può verificarli, e inoltre confonde i programmatori. Non c'è da +sorprendersi che MicroSoft faccia programmi bacati. + +Le variabili LOCALI dovrebbero avere nomi corti, e significativi. Se avete +un qualsiasi contatore di ciclo, probabilmente sarà chiamato ``i``. +Chiamarlo ``loop_counter`` non è produttivo, non ci sono possibilità che +``i`` possa non essere capito. Analogamente, ``tmp`` può essere una qualsiasi +variabile che viene usata per salvare temporaneamente un valore. + +Se avete paura di fare casino coi nomi delle vostre variabili locali, allora +avete un altro problema che è chiamato sindrome dello squilibrio dell'ormone +della crescita delle funzioni. Vedere il capitolo 6 (funzioni). + +5) Definizione di tipi (typedef) +-------------------------------- + +Per favore non usate cose come ``vps_t``. +Usare il typedef per strutture e puntatori è uno **sbaglio**. Quando vedete: + +.. code-block:: c + + vps_t a; + +nei sorgenti, cosa significa? +Se, invece, dicesse: + +.. code-block:: c + + struct virtual_container *a; + +potreste dire cos'è effettivamente ``a``. + +Molte persone pensano che la definizione dei tipi ``migliori la leggibilità``. +Non molto. Sono utili per: + + (a) gli oggetti completamente opachi (dove typedef viene proprio usato allo + scopo di **nascondere** cosa sia davvero l'oggetto). + + Esempio: ``pte_t`` eccetera sono oggetti opachi che potete usare solamente + con le loro funzioni accessorie. + + .. note:: + Gli oggetti opachi e le ``funzioni accessorie`` non sono, di per se, + una bella cosa. Il motivo per cui abbiamo cose come pte_t eccetera è + che davvero non c'è alcuna informazione portabile. + + (b) i tipi chiaramente interi, dove l'astrazione **aiuta** ad evitare + confusione sul fatto che siano ``int`` oppure ``long``. + + u8/u16/u32 sono typedef perfettamente accettabili, anche se ricadono + nella categoria (d) piuttosto che in questa. + + .. note:: + + Ancora - dev'esserci una **ragione** per farlo. Se qualcosa è + ``unsigned long``, non c'è alcun bisogno di avere: + + typedef unsigned long myfalgs_t; + + ma se ci sono chiare circostanze in cui potrebbe essere ``unsigned int`` + e in altre configurazioni ``unsigned long``, allora certamente typedef + è una buona scelta. + + (c) quando di rado create letteralmente dei **nuovi** tipi su cui effettuare + verifiche. + + (d) circostanze eccezionali, in cui si definiscono nuovi tipi identici a + quelli definiti dallo standard C99. + + Nonostante ci voglia poco tempo per abituare occhi e cervello all'uso dei + tipi standard come ``uint32_t``, alcune persone ne obiettano l'uso. + + Perciò, i tipi specifici di Linux ``u8/u16/u32/u64`` e i loro equivalenti + con segno, identici ai tipi standard, sono permessi- tuttavia, non sono + obbligatori per il nuovo codice. + + (e) i tipi sicuri nella spazio utente. + + In alcune strutture dati visibili dallo spazio utente non possiamo + richiedere l'uso dei tipi C99 e nemmeno i vari ``u32`` descritti prima. + Perciò, utilizziamo __u32 e tipi simili in tutte le strutture dati + condivise con lo spazio utente. + +Magari ci sono altri casi validi, ma la regola di base dovrebbe essere di +non usare MAI MAI un typedef a meno che non rientri in una delle regole +descritte qui. + +In generale, un puntatore, o una struttura a cui si ha accesso diretto in +modo ragionevole, non dovrebbero **mai** essere definite con un typedef. + +6) Funzioni +----------- + +Le funzioni dovrebbero essere brevi e carine, e fare una cosa sola. Dovrebbero +occupare uno o due schermi di testo (come tutti sappiamo, la dimensione +di uno schermo secondo ISO/ANSI è di 80x24), e fare una cosa sola e bene. + +La massima lunghezza di una funziona è inversamente proporzionale alla sua +complessità e al livello di indentazione di quella funzione. Quindi, se avete +una funzione che è concettualmente semplice ma che è implementata come un +lunga (ma semplice) sequenza di caso-istruzione, dove avete molte piccole cose +per molti casi differenti, allora va bene avere funzioni più lunghe. + +Comunque, se avete una funzione complessa e sospettate che uno studente +non particolarmente dotato del primo anno delle scuole superiori potrebbe +non capire cosa faccia la funzione, allora dovreste attenervi strettamente ai +limiti. Usate funzioni di supporto con nomi descrittivi (potete chiedere al +compilatore di renderle inline se credete che sia necessario per le +prestazioni, e probabilmente farà un lavoro migliore di quanto avreste potuto +fare voi). + +Un'altra misura delle funzioni sono il numero di variabili locali. Non +dovrebbero eccedere le 5-10, oppure state sbagliando qualcosa. Ripensate la +funzione, e dividetela in pezzettini. Generalmente, un cervello umano può +seguire facilmente circa 7 cose diverse, di più lo confonderebbe. Lo sai +d'essere brillante, ma magari vorresti riuscire a capire cos'avevi fatto due +settimane prima. + +Nei file sorgenti, separate le funzioni con una riga vuota. Se la funzione è +esportata, la macro **EXPORT** per questa funzione deve seguire immediatamente +la riga della parentesi graffa di chiusura. Ad esempio: + +.. code-block:: c + + int system_is_up(void) + { + return system_state == SYSTEM_RUNNING; + } + EXPORT_SYMBOL(system_is_up); + +Nei prototipi di funzione, includete i nomi dei parametri e i loro tipi. +Nonostante questo non sia richiesto dal linguaggio C, in Linux viene preferito +perché è un modo semplice per aggiungere informazioni importanti per il +lettore. + +7) Centralizzare il ritorno delle funzioni +------------------------------------------ + +Sebbene sia deprecata da molte persone, l'istruzione goto è impiegata di +frequente dai compilatori sotto forma di salto incondizionato. + +L'istruzione goto diventa utile quando una funzione ha punti d'uscita multipli +e vanno eseguite alcune procedure di pulizia in comune. Se non è necessario +pulire alcunché, allora ritornate direttamente. + +Assegnate un nome all'etichetta di modo che suggerisca cosa fa la goto o +perché esiste. Un esempio di un buon nome potrebbe essere ``out_free_buffer:`` +se la goto libera (free) un ``buffer``. Evitate l'uso di nomi GW-BASIC come +``err1:`` ed ``err2:``, potreste doverli riordinare se aggiungete o rimuovete +punti d'uscita, e inoltre rende difficile verificarne la correttezza. + +I motivo per usare le goto sono: + +- i salti incondizionati sono più facili da capire e seguire +- l'annidamento si riduce +- si evita di dimenticare, per errore, di aggiornare un singolo punto d'uscita +- aiuta il compilatore ad ottimizzare il codice ridondante ;) + +.. code-block:: c + + int fun(int a) + { + int result = 0; + char *buffer; + + buffer = kmalloc(SIZE, GFP_KERNEL); + if (!buffer) + return -ENOMEM; + + if (condition1) { + while (loop1) { + ... + } + result = 1; + goto out_free_buffer; + } + ... + out_free_buffer: + kfree(buffer); + return result; + } + +Un baco abbastanza comune di cui bisogna prendere nota è il ``one err bugs`` +che assomiglia a questo: + +.. code-block:: c + + err: + kfree(foo->bar); + kfree(foo); + return ret; + +Il baco in questo codice è che in alcuni punti d'uscita la variabile ``foo`` è +NULL. Normalmente si corregge questo baco dividendo la gestione dell'errore in +due parti ``err_free_bar:`` e ``err_free_foo:``: + +.. code-block:: c + + err_free_bar: + kfree(foo->bar); + err_free_foo: + kfree(foo); + return ret; + +Idealmente, dovreste simulare condizioni d'errore per verificare i vostri +percorsi d'uscita. + + +8) Commenti +----------- + +I commenti sono una buona cosa, ma c'è anche il rischio di esagerare. MAI +spiegare COME funziona il vostro codice in un commento: è molto meglio +scrivere il codice di modo che il suo funzionamento sia ovvio, inoltre +spiegare codice scritto male è una perdita di tempo. + +Solitamente, i commenti devono dire COSA fa il codice, e non COME lo fa. +Inoltre, cercate di evitare i commenti nel corpo della funzione: se la +funzione è così complessa che dovete commentarla a pezzi, allora dovreste +tornare al punto 6 per un momento. Potete mettere dei piccoli commenti per +annotare o avvisare il lettore circa un qualcosa di particolarmente arguto +(o brutto), ma cercate di non esagerare. Invece, mettete i commenti in +testa alla funzione spiegando alle persone cosa fa, e possibilmente anche +il PERCHÉ. + +Per favore, quando commentate una funzione dell'API del kernel usate il +formato kernel-doc. Per maggiori dettagli, leggete i file in +:ref::ref:`Documentation/translations/it_IT/doc-guide/ <it_doc_guide>` e in +``script/kernel-doc``. + +Lo stile preferito per i commenti più lunghi (multi-riga) è: + +.. code-block:: c + + /* + * This is the preferred style for multi-line + * comments in the Linux kernel source code. + * Please use it consistently. + * + * Description: A column of asterisks on the left side, + * with beginning and ending almost-blank lines. + */ + +Per i file in net/ e in drivers/net/ lo stile preferito per i commenti +più lunghi (multi-riga) è leggermente diverso. + +.. code-block:: c + + /* The preferred comment style for files in net/ and drivers/net + * looks like this. + * + * It is nearly the same as the generally preferred comment style, + * but there is no initial almost-blank line. + */ + +È anche importante commentare i dati, sia per i tipi base che per tipi +derivati. A questo scopo, dichiarate un dato per riga (niente virgole +per una dichiarazione multipla). Questo vi lascerà spazio per un piccolo +commento per spiegarne l'uso. + + +9) Avete fatto un pasticcio +--------------------------- + +Va bene, li facciamo tutti. Probabilmente vi è stato detto dal vostro +aiutante Unix di fiducia che ``GNU emacs`` formatta automaticamente il +codice C per conto vostro, e avete notato che sì, in effetti lo fa, ma che +i modi predefiniti non sono proprio allettanti (infatti, sono peggio che +premere tasti a caso - un numero infinito di scimmie che scrivono in +GNU emacs non faranno mai un buon programma). + +Quindi, potete sbarazzarvi di GNU emacs, o riconfigurarlo con valori più +sensati. Per fare quest'ultima cosa, potete appiccicare il codice che +segue nel vostro file .emacs: + +.. code-block:: none + + (defun c-lineup-arglist-tabs-only (ignored) + "Line up argument lists by tabs, not spaces" + (let* ((anchor (c-langelem-pos c-syntactic-element)) + (column (c-langelem-2nd-pos c-syntactic-element)) + (offset (- (1+ column) anchor)) + (steps (floor offset c-basic-offset))) + (* (max steps 1) + c-basic-offset))) + + (add-hook 'c-mode-common-hook + (lambda () + ;; Add kernel style + (c-add-style + "linux-tabs-only" + '("linux" (c-offsets-alist + (arglist-cont-nonempty + c-lineup-gcc-asm-reg + c-lineup-arglist-tabs-only)))))) + + (add-hook 'c-mode-hook + (lambda () + (let ((filename (buffer-file-name))) + ;; Enable kernel mode for the appropriate files + (when (and filename + (string-match (expand-file-name "~/src/linux-trees") + filename)) + (setq indent-tabs-mode t) + (setq show-trailing-whitespace t) + (c-set-style "linux-tabs-only"))))) + +Questo farà funzionare meglio emacs con lo stile del kernel per i file che +si trovano nella cartella ``~/src/linux-trees``. + +Ma anche se doveste fallire nell'ottenere una formattazione sensata in emacs +non tutto è perduto: usate ``indent``. + +Ora, ancora, GNU indent ha la stessa configurazione decerebrata di GNU emacs, +ed è per questo che dovete passargli alcune opzioni da riga di comando. +Tuttavia, non è così terribile, perché perfino i creatori di GNU indent +riconoscono l'autorità di K&R (le persone del progetto GNU non sono cattive, +sono solo mal indirizzate sull'argomento), quindi date ad indent le opzioni +``-kr -i8`` (che significa ``K&R, 8 caratteri di indentazione``), o utilizzate +``scripts/Lindent`` che indenterà usando l'ultimo stile. + +``indent`` ha un sacco di opzioni, e specialmente quando si tratta di +riformattare i commenti dovreste dare un'occhiata alle pagine man. +Ma ricordatevi: ``indent`` non è un correttore per una cattiva programmazione. + +Da notare che potete utilizzare anche ``clang-format`` per aiutarvi con queste +regole, per riformattare rapidamente ad automaticamente alcune parti del +vostro codice, e per revisionare interi file al fine di identificare errori +di stile, refusi e possibilmente anche delle migliorie. È anche utile per +ordinare gli ``#include``, per allineare variabili/macro, per ridistribuire +il testo e altre cose simili. +Per maggiori dettagli, consultate il file +:ref:`Documentation/translations/it_IT/process/clang-format.rst <it_clangformat>`. + + +10) File di configurazione Kconfig +---------------------------------- + +Per tutti i file di configurazione Kconfig* che si possono trovare nei +sorgenti, l'indentazione è un po' differente. Le linee dopo un ``config`` +sono indentate con un tab, mentre il testo descrittivo è indentato di +ulteriori due spazi. Esempio:: + + config AUDIT + bool "Auditing support" + depends on NET + help + Enable auditing infrastructure that can be used with another + kernel subsystem, such as SELinux (which requires this for + logging of avc messages output). Does not do system-call + auditing without CONFIG_AUDITSYSCALL. + +Le funzionalità davvero pericolose (per esempio il supporto alla scrittura +per certi filesystem) dovrebbero essere dichiarate chiaramente come tali +nella stringa di titolo:: + + config ADFS_FS_RW + bool "ADFS write support (DANGEROUS)" + depends on ADFS_FS + ... + +Per la documentazione completa sui file di configurazione, consultate +il documento Documentation/translations/it_IT/kbuild/kconfig-language.txt + + +11) Strutture dati +------------------ + +Le strutture dati che hanno una visibilità superiore al contesto del +singolo thread in cui vengono create e distrutte, dovrebbero sempre +avere un contatore di riferimenti. Nel kernel non esiste un +*garbage collector* (e fuori dal kernel i *garbage collector* sono lenti +e inefficienti), questo significa che **dovete** assolutamente avere un +contatore di riferimenti per ogni cosa che usate. + +Avere un contatore di riferimenti significa che potete evitare la +sincronizzazione e permette a più utenti di accedere alla struttura dati +in parallelo - e non doversi preoccupare di una struttura dati che +improvvisamente sparisce dalla loro vista perché il loro processo dormiva +o stava facendo altro per un attimo. + +Da notare che la sincronizzazione **non** si sostituisce al conteggio dei +riferimenti. La sincronizzazione ha lo scopo di mantenere le strutture +dati coerenti, mentre il conteggio dei riferimenti è una tecnica di gestione +della memoria. Solitamente servono entrambe le cose, e non vanno confuse fra +di loro. + +Quando si hanno diverse classi di utenti, le strutture dati possono avere +due livelli di contatori di riferimenti. Il contatore di classe conta +il numero dei suoi utenti, e il contatore globale viene decrementato una +sola volta quando il contatore di classe va a zero. + +Un esempio di questo tipo di conteggio dei riferimenti multi-livello può +essere trovato nella gestore della memoria (``struct mm_sturct``: mm_user e +mm_count), e nel codice dei filesystem (``struct super_block``: s_count e +s_active). + +Ricordatevi: se un altro thread può trovare la vostra struttura dati, e non +avete un contatore di riferimenti per essa, quasi certamente avete un baco. + +12) Macro, enumerati e RTL +--------------------------- + +I nomi delle macro che definiscono delle costanti e le etichette degli +enumerati sono scritte in maiuscolo. + +.. code-block:: c + + #define CONSTANT 0x12345 + +Gli enumerati sono da preferire quando si definiscono molte costanti correlate. + +I nomi delle macro in MAIUSCOLO sono preferibili ma le macro che assomigliano +a delle funzioni possono essere scritte in minuscolo. + +Generalmente, le funzioni inline sono preferibili rispetto alle macro che +sembrano funzioni. + +Le macro che contengono più istruzioni dovrebbero essere sempre chiuse in un +blocco do - while: + +.. code-block:: c + + #define macrofun(a, b, c) \ + do { \ + if (a == 5) \ + do_this(b, c); \ + } while (0) + +Cose da evitare quando si usano le macro: + +1) le macro che hanno effetti sul flusso del codice: + +.. code-block:: c + + #define FOO(x) \ + do { \ + if (blah(x) < 0) \ + return -EBUGGERED; \ + } while (0) + +sono **proprio** una pessima idea. Sembra una chiamata a funzione ma termina +la funzione chiamante; non cercate di rompere il decodificatore interno di +chi legge il codice. + +2) le macro che dipendono dall'uso di una variabile locale con un nome magico: + +.. code-block:: c + + #define FOO(val) bar(index, val) + +potrebbe sembrare una bella cosa, ma è dannatamente confusionario quando uno +legge il codice e potrebbe romperlo con una cambiamento che sembra innocente. + +3) le macro con argomenti che sono utilizzati come l-values; questo potrebbe +ritorcervisi contro se qualcuno, per esempio, trasforma FOO in una funzione +inline. + +4) dimenticatevi delle precedenze: le macro che definiscono espressioni devono +essere racchiuse fra parentesi. State attenti a problemi simili con le macro +parametrizzate. + +.. code-block:: c + + #define CONSTANT 0x4000 + #define CONSTEXP (CONSTANT | 3) + +5) collisione nello spazio dei nomi quando si definisce una variabile locale in +una macro che sembra una funzione: + +.. code-block:: c + + #define FOO(x) \ + ({ \ + typeof(x) ret; \ + ret = calc_ret(x); \ + (ret); \ + }) + +ret è un nome comune per una variabile locale - __foo_ret difficilmente +andrà in conflitto con una variabile già esistente. + +Il manuale di cpp si occupa esaustivamente delle macro. Il manuale di sviluppo +di gcc copre anche l'RTL che viene usato frequentemente nel kernel per il +linguaggio assembler. + +13) Visualizzare i messaggi del kernel +-------------------------------------- + +Agli sviluppatori del kernel piace essere visti come dotti. Tenete un occhio +di riguardo per l'ortografia e farete una belle figura. In inglese, evitate +l'uso di parole mozzate come ``dont``: usate ``do not`` oppure ``don't``. +Scrivete messaggi concisi, chiari, e inequivocabili. + +I messaggi del kernel non devono terminare con un punto fermo. + +Scrivere i numeri fra parentesi (%d) non migliora alcunché e per questo +dovrebbero essere evitati. + +Ci sono alcune macro per la diagnostica in <linux/device.h> che dovreste +usare per assicurarvi che i messaggi vengano associati correttamente ai +dispositivi e ai driver, e che siano etichettati correttamente: dev_err(), +dev_warn(), dev_info(), e così via. Per messaggi che non sono associati ad +alcun dispositivo, <linux/printk.h> definisce pr_info(), pr_warn(), pr_err(), +eccetera. + +Tirar fuori un buon messaggio di debug può essere una vera sfida; e quando +l'avete può essere d'enorme aiuto per risolvere problemi da remoto. +Tuttavia, i messaggi di debug sono gestiti differentemente rispetto agli +altri. Le funzioni pr_XXX() stampano incondizionatamente ma pr_debug() no; +essa non viene compilata nella configurazione predefinita, a meno che +DEBUG o CONFIG_DYNAMIC_DEBUG non vengono impostati. Questo vale anche per +dev_dbg() e in aggiunta VERBOSE_DEBUG per aggiungere i messaggi dev_vdbg(). + +Molti sottosistemi hanno delle opzioni di debug in Kconfig che aggiungono +-DDEBUG nei corrispettivi Makefile, e in altri casi aggiungono #define DEBUG +in specifici file. Infine, quando un messaggio di debug dev'essere stampato +incondizionatamente, per esempio perché siete già in una sezione di debug +racchiusa in #ifdef, potete usare printk(KERN_DEBUG ...). + +14) Assegnare memoria +--------------------- + +Il kernel fornisce i seguenti assegnatori ad uso generico: +kmalloc(), kzalloc(), kmalloc_array(), kcalloc(), vmalloc(), e vzalloc(). +Per maggiori informazioni, consultate la documentazione dell'API. + +Il modo preferito per passare la dimensione di una struttura è il seguente: + +.. code-block:: c + + p = kmalloc(sizeof(*p), ...); + +La forma alternativa, dove il nome della struttura viene scritto interamente, +peggiora la leggibilità e introduce possibili bachi quando il tipo di +puntatore cambia tipo ma il corrispondente sizeof non viene aggiornato. + +Il valore di ritorno è un puntatore void, effettuare un cast su di esso è +ridondante. La conversione fra un puntatore void e un qualsiasi altro tipo +di puntatore è garantito dal linguaggio di programmazione C. + +Il modo preferito per assegnare un vettore è il seguente: + +.. code-block:: c + + p = kmalloc_array(n, sizeof(...), ...); + +Il modo preferito per assegnare un vettore a zero è il seguente: + +.. code-block:: c + + p = kcalloc(n, sizeof(...), ...); + +Entrambe verificano la condizione di overflow per la dimensione +d'assegnamento n * sizeof(...), se accade ritorneranno NULL. + +15) Il morbo inline +------------------- + +Sembra che ci sia la percezione errata che gcc abbia una qualche magica +opzione "rendimi più veloce" chiamata ``inline``. In alcuni casi l'uso di +inline è appropriato (per esempio in sostituzione delle macro, vedi +capitolo 12), ma molto spesso non lo è. L'uso abbondante della parola chiave +inline porta ad avere un kernel più grande, che si traduce in un sistema nel +suo complesso più lento per via di una cache per le istruzioni della CPU più +grande e poi semplicemente perché ci sarà meno spazio disponibile per una +pagina di cache. Pensateci un attimo; una fallimento nella cache causa una +ricerca su disco che può tranquillamente richiedere 5 millisecondi. Ci sono +TANTI cicli di CPU che potrebbero essere usati in questi 5 millisecondi. + +Spesso le persone dicono che aggiungere inline a delle funzioni dichiarate +static e utilizzare una sola volta è sempre una scelta vincente perché non +ci sono altri compromessi. Questo è tecnicamente vero ma gcc è in grado di +trasformare automaticamente queste funzioni in inline; i problemi di +manutenzione del codice per rimuovere gli inline quando compare un secondo +utente surclassano il potenziale vantaggio nel suggerire a gcc di fare una +cosa che avrebbe fatto comunque. + +16) Nomi e valori di ritorno delle funzioni +------------------------------------------- + +Le funzioni possono ritornare diversi tipi di valori, e uno dei più comuni +è quel valore che indica se una funzione ha completato con successo o meno. +Questo valore può essere rappresentato come un codice di errore intero +(-Exxx = fallimento, 0 = successo) oppure un booleano di successo +(0 = fallimento, non-zero = successo). + +Mischiare questi due tipi di rappresentazioni è un terreno fertile per +i bachi più insidiosi. Se il linguaggio C includesse una forte distinzione +fra gli interi e i booleani, allora il compilatore potrebbe trovare questi +errori per conto nostro ... ma questo non c'è. Per evitare di imbattersi +in questo tipo di baco, seguite sempre la seguente convenzione:: + + Se il nome di una funzione è un'azione o un comando imperativo, + essa dovrebbe ritornare un codice di errore intero. Se il nome + è un predicato, la funzione dovrebbe ritornare un booleano di + "successo" + +Per esempio, ``add work`` è un comando, e la funzione add_work() ritorna 0 +in caso di successo o -EBUSY in caso di fallimento. Allo stesso modo, +``PCI device present`` è un predicato, e la funzione pci_dev_present() ritorna +1 se trova il dispositivo corrispondente con successo, altrimenti 0. + +Tutte le funzioni esportate (EXPORT) devono rispettare questa convenzione, e +così dovrebbero anche tutte le funzioni pubbliche. Le funzioni private +(static) possono non seguire questa convenzione, ma è comunque raccomandato +che lo facciano. + +Le funzioni il cui valore di ritorno è il risultato di una computazione, +piuttosto che l'indicazione sul successo di tale computazione, non sono +soggette a questa regola. Solitamente si indicano gli errori ritornando un +qualche valore fuori dai limiti. Un tipico esempio è quello delle funzioni +che ritornano un puntatore; queste utilizzano NULL o ERR_PTR come meccanismo +di notifica degli errori. + +17) Non reinventate le macro del kernel +--------------------------------------- + +Il file di intestazione include/linux/kernel.h contiene un certo numero +di macro che dovreste usare piuttosto che implementarne una qualche variante. +Per esempio, se dovete calcolare la lunghezza di un vettore, sfruttate la +macro: + +.. code-block:: c + + #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) + +Analogamente, se dovete calcolare la dimensione di un qualche campo di una +struttura, usate + +.. code-block:: c + + #define FIELD_SIZEOF(t, f) (sizeof(((t*)0)->f)) + +Ci sono anche le macro min() e max() che, se vi serve, effettuano un controllo +rigido sui tipi. Sentitevi liberi di leggere attentamente questo file +d'intestazione per scoprire cos'altro è stato definito che non dovreste +reinventare nel vostro codice. + +18) Linee di configurazione degli editor e altre schifezze +----------------------------------------------------------- + +Alcuni editor possono interpretare dei parametri di configurazione integrati +nei file sorgenti e indicati con dai marcatori speciali. Per esempio, emacs +interpreta le linee marcate nel seguente modo: + +.. code-block:: c + + -*- mode: c -*- + +O come queste: + +.. code-block:: c + + /* + Local Variables: + compile-command: "gcc -DMAGIC_DEBUG_FLAG foo.c" + End: + */ + +Vim interpreta i marcatori come questi: + +.. code-block:: c + + /* vim:set sw=8 noet */ + +Non includete nessuna di queste cose nei file sorgenti. Le persone hanno le +proprie configurazioni personali per l'editor, e i vostri sorgenti non +dovrebbero sovrascrivergliele. Questo vale anche per i marcatori +d'indentazione e di modalità d'uso. Le persone potrebbero aver configurato una +modalità su misura, oppure potrebbero avere qualche altra magia per far +funzionare bene l'indentazione. + +19) Inline assembly +--------------------- + +Nel codice specifico per un'architettura, potreste aver bisogno di codice +*inline assembly* per interfacciarvi col processore o con una funzionalità +specifica della piattaforma. Non esitate a farlo quando è necessario. +Comunque, non usatele gratuitamente quando il C può fare la stessa cosa. +Potete e dovreste punzecchiare l'hardware in C quando è possibile. + +Considerate la scrittura di una semplice funzione che racchiude pezzi comuni +di codice assembler piuttosto che continuare a riscrivere delle piccole +varianti. Ricordatevi che l' *inline assembly* può utilizzare i parametri C. + +Il codice assembler più corposo e non banale dovrebbe andare nei file .S, +coi rispettivi prototipi C definiti nei file d'intestazione. I prototipi C +per le funzioni assembler dovrebbero usare ``asmlinkage``. + +Potreste aver bisogno di marcare il vostro codice asm come volatile al fine +d'evitare che GCC lo rimuova quando pensa che non ci siano effetti collaterali. +Non c'è sempre bisogno di farlo, e farlo quando non serve limita le +ottimizzazioni. + +Quando scrivete una singola espressione *inline assembly* contenente più +istruzioni, mettete ognuna di queste istruzioni in una stringa e riga diversa; +ad eccezione dell'ultima stringa/istruzione, ognuna deve terminare con ``\n\t`` +al fine di allineare correttamente l'assembler che verrà generato: + +.. code-block:: c + + asm ("magic %reg1, #42\n\t" + "more_magic %reg2, %reg3" + : /* outputs */ : /* inputs */ : /* clobbers */); + +20) Compilazione sotto condizione +--------------------------------- + +Ovunque sia possibile, non usate le direttive condizionali del preprocessore +(#if, #ifdef) nei file .c; farlo rende il codice difficile da leggere e da +seguire. Invece, usate queste direttive nei file d'intestazione per definire +le funzioni usate nei file .c, fornendo i relativi stub nel caso #else, +e quindi chiamate queste funzioni senza condizioni di preprocessore. Il +compilatore non produrrà alcun codice per le funzioni stub, produrrà gli +stessi risultati, e la logica rimarrà semplice da seguire. + +È preferibile non compilare intere funzioni piuttosto che porzioni d'esse o +porzioni d'espressioni. Piuttosto che mettere una ifdef in un'espressione, +fattorizzate parte dell'espressione, o interamente, in funzioni e applicate +la direttiva condizionale su di esse. + +Se avete una variabile o funzione che potrebbe non essere usata in alcune +configurazioni, e quindi il compilatore potrebbe avvisarvi circa la definizione +inutilizzata, marcate questa definizione come __maybe_used piuttosto che +racchiuderla in una direttiva condizionale del preprocessore. (Comunque, +se una variabile o funzione è *sempre* inutilizzata, rimuovetela). + +Nel codice, dov'è possibile, usate la macro IS_ENABLED per convertire i +simboli Kconfig in espressioni booleane C, e quindi usatela nelle classiche +condizioni C: + +.. code-block:: c + + if (IS_ENABLED(CONFIG_SOMETHING)) { + ... + } + +Il compilatore valuterà la condizione come costante (constant-fold), e quindi +includerà o escluderà il blocco di codice come se fosse in un #ifdef, quindi +non ne aumenterà il tempo di esecuzione. Tuttavia, questo permette al +compilatore C di vedere il codice nel blocco condizionale e verificarne la +correttezza (sintassi, tipi, riferimenti ai simboli, eccetera). Quindi +dovete comunque utilizzare #ifdef se il codice nel blocco condizionale esiste +solo quando la condizione è soddisfatta. + +Alla fine di un blocco corposo di #if o #ifdef (più di alcune linee), +mettete un commento sulla stessa riga di #endif, annotando la condizione +che termina. Per esempio: + +.. code-block:: c + + #ifdef CONFIG_SOMETHING + ... + #endif /* CONFIG_SOMETHING */ + +Appendice I) riferimenti +------------------------ + +The C Programming Language, Second Edition +by Brian W. Kernighan and Dennis M. Ritchie. +Prentice Hall, Inc., 1988. +ISBN 0-13-110362-8 (paperback), 0-13-110370-9 (hardback). + +The Practice of Programming +by Brian W. Kernighan and Rob Pike. +Addison-Wesley, Inc., 1999. +ISBN 0-201-61586-X. + +Manuali GNU - nei casi in cui sono compatibili con K&R e questo documento - +per indent, cpp, gcc e i suoi dettagli interni, tutto disponibile qui +http://www.gnu.org/manual/ + +WG14 è il gruppo internazionale di standardizzazione per il linguaggio C, +URL: http://www.open-std.org/JTC1/SC22/WG14/ + +Kernel process/coding-style.rst, by greg@kroah.com at OLS 2002: +http://www.kroah.com/linux/talks/ols_2002_kernel_codingstyle_talk/html/ diff --git a/Documentation/translations/it_IT/process/development-process.rst b/Documentation/translations/it_IT/process/development-process.rst new file mode 100644 index 000000000000..f1a6eca30824 --- /dev/null +++ b/Documentation/translations/it_IT/process/development-process.rst @@ -0,0 +1,33 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/development-process.rst <development_process_main>` +:Translator: Alessia Mantegazza <amantegazza@vaga.pv.it> + +.. _it_development_process_main: + +Una guida al processo di sviluppo del Kernel +============================================ + +Contenuti: + +.. toctree:: + :numbered: + :maxdepth: 2 + + 1.Intro + 2.Process + 3.Early-stage + 4.Coding + 5.Posting + 6.Followthrough + 7.AdvancedTopics + 8.Conclusion + +Lo scopo di questo documento è quello di aiutare gli sviluppatori (ed i loro +supervisori) a lavorare con la communità di sviluppo con il minimo sforzo. È +un tentativo di documentare il funzionamento di questa communità in modo che +sia accessibile anche a coloro che non hanno famigliarità con lo sviluppo del +Kernel Linux (o, anzi, con lo sviluppo di software libero in generale). Benchè +qui sia presente del materiale tecnico, questa è una discussione rivolta in +particolare al procedimento, e quindi per essere compreso non richiede una +conoscenza approfondità sullo sviluppo del kernel. diff --git a/Documentation/translations/it_IT/process/email-clients.rst b/Documentation/translations/it_IT/process/email-clients.rst new file mode 100644 index 000000000000..224ab031ffd3 --- /dev/null +++ b/Documentation/translations/it_IT/process/email-clients.rst @@ -0,0 +1,12 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/email-clients.rst <email_clients>` + +.. _it_email_clients: + +Informazioni sui programmi di posta elettronica per Linux +========================================================= + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/howto.rst b/Documentation/translations/it_IT/process/howto.rst new file mode 100644 index 000000000000..909e6a55bc43 --- /dev/null +++ b/Documentation/translations/it_IT/process/howto.rst @@ -0,0 +1,655 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/howto.rst <process_howto>` +:Translator: Alessia Mantegazza <amantegazza@vaga.pv.it> + +.. _it_process_howto: + +Come partecipare allo sviluppo del kernel Linux +=============================================== + +Questo è il documento fulcro di quanto trattato sull'argomento. +Esso contiene le istruzioni su come diventare uno sviluppatore +del kernel Linux e spiega come lavorare con la comunità di +sviluppo kernel Linux. Il documento non tratterà alcun aspetto +tecnico relativo alla programmazione del kernel, ma vi aiuterà +indirizzandovi sulla corretta strada. + +Se qualsiasi cosa presente in questo documento diventasse obsoleta, +vi preghiamo di inviare le correzioni agli amministratori di questo +file, indicati in fondo al presente documento. + +Introduzione +------------ +Dunque, volete imparare come diventare sviluppatori del kernel Linux? +O vi è stato detto dal vostro capo, "Vai, scrivi un driver Linux per +questo dispositivo". Bene, l'obbiettivo di questo documento è quello +di insegnarvi tutto ciò che dovete sapere per raggiungere il vostro +scopo descrivendo il procedimento da seguire e consigliandovi +su come lavorare con la comunità. Il documento cercherà, inoltre, +di spiegare alcune delle ragioni per le quali la comunità lavora in un +modo suo particolare. + +Il kernel è scritto prevalentemente nel linguaggio C con alcune parti +specifiche dell'architettura scritte in linguaggio assembly. +Per lo sviluppo kernel è richiesta una buona conoscenza del linguaggio C. +L'assembly (di qualsiasi architettura) non è richiesto, a meno che non +pensiate di fare dello sviluppo di basso livello per un'architettura. +Sebbene essi non siano un buon sostituto ad un solido studio del +linguaggio C o ad anni di esperienza, i seguenti libri sono, se non +altro, utili riferimenti: + +- "The C Programming Language" di Kernighan e Ritchie [Prentice Hall] +- "Practical C Programming" di Steve Oualline [O'Reilly] +- "C: A Reference Manual" di Harbison and Steele [Prentice Hall] + +Il kernel è stato scritto usando GNU C e la toolchain GNU. +Sebbene si attenga allo standard ISO C89, esso utilizza una serie di +estensioni che non sono previste in questo standard. Il kernel è un +ambiente C indipendente, che non ha alcuna dipendenza dalle librerie +C standard, così alcune parti del C standard non sono supportate. +Le divisioni ``long long`` e numeri in virgola mobile non sono permessi. +Qualche volta è difficile comprendere gli assunti che il kernel ha +riguardo gli strumenti e le estensioni in uso, e sfortunatamente non +esiste alcuna indicazione definitiva. Per maggiori informazioni, controllate, +la pagina `info gcc`. + +Tenete a mente che state cercando di apprendere come lavorare con la comunità +di sviluppo già esistente. Questo è un gruppo eterogeneo di persone, con alti +standard di codifica, di stile e di procedura. Questi standard sono stati +creati nel corso del tempo basandosi su quanto hanno riscontrato funzionare al +meglio per un squadra così grande e geograficamente sparsa. Cercate di +imparare, in anticipo, il più possibile circa questi standard, poichè ben +spiegati; non aspettatevi che gli altri si adattino al vostro modo di fare +o a quello della vostra azienda. + +Note legali +------------ +Il codice sorgente del kernel Linux è rilasciato sotto GPL. Siete pregati +di visionare il file, COPYING, presente nella cartella principale dei +sorgente, per eventuali dettagli sulla licenza. Se avete ulteriori domande +sulla licenza, contattate un avvocato, non chiedete sulle liste di discussione +del kernel Linux. Le persone presenti in queste liste non sono avvocati, +e non dovreste basarvi sulle loro dichiarazioni in materia giuridica. + +Per domande più frequenti e risposte sulla licenza GPL, guardare: + + https://www.gnu.org/licenses/gpl-faq.html + +Documentazione +-------------- +I sorgenti del kernel Linux hanno una vasta base di documenti che vi +insegneranno come interagire con la comunità del kernel. Quando nuove +funzionalità vengono aggiunte al kernel, si raccomanda di aggiungere anche i +relativi file di documentatione che spiegano come usarele. +Quando un cambiamento del kernel genera anche un cambiamento nell'interfaccia +con lo spazio utente, è raccomandabile che inviate una notifica o una +correzione alle pagine *man* spiegando tale modifica agli amministratori di +queste pagine all'indirizzo mtk.manpages@gmail.com, aggiungendo +in CC la lista linux-api@vger.kernel.org. + +Di seguito una lista di file che sono presenti nei sorgente del kernel e che +è richiesto che voi leggiate: + + :ref:`Documentation/translations/it_IT/admin-guide/README.rst <it_readme>` + Questo file da una piccola anteprima del kernel Linux e descrive il + minimo necessario per configurare e generare il kernel. I novizi + del kernel dovrebbero iniziare da qui. + + :ref:`Documentation/translations/it_IT/process/changes.rst <it_changes>` + + Questo file fornisce una lista dei pacchetti software necessari + a compilare e far funzionare il kernel con successo. + + :ref:`Documentation/translations/it_IT/process/coding-style.rst <it_codingstyle>` + + Questo file descrive lo stile della codifica per il kernel Linux, + e parte delle motivazioni che ne sono alla base. Tutto il nuovo codice deve + seguire le linee guida in questo documento. Molti amministratori + accetteranno patch solo se queste osserveranno tali regole, e molte + persone revisioneranno il codice solo se scritto nello stile appropriato. + + :ref:`Documentation/translations/it_IT/process/submitting-patches.rst <it_submittingpatches>` e + :ref:`Documentation/translations/it_IT/process/submitting-drivers.rst <it_submittingdrivers>` + + Questo file descrive dettagliatamente come creare ed inviare una patch + con successo, includendo (ma non solo questo): + + - Contenuto delle email + - Formato delle email + - I destinatari delle email + + Seguire tali regole non garantirà il successo (tutte le patch sono soggette + a controlli realitivi a contenuto e stile), ma non seguirle lo precluderà + sempre. + + Altre ottime descrizioni di come creare buone patch sono: + + "The Perfect Patch" + https://www.ozlabs.org/~akpm/stuff/tpp.txt + + "Linux kernel patch submission format" + http://linux.yyz.us/patch-format.html + + :ref:`Documentation/process/translations/it_IT/stable-api-nonsense.rst <it_stable_api_nonsense>` + + Questo file descrive la motivazioni sottostanti la conscia decisione di + non avere un API stabile all'interno del kernel, incluso cose come: + + - Sottosistemi shim-layers (per compatibilità?) + - Portabilità fra Sistemi Operativi dei driver. + - Attenuare i rapidi cambiamenti all'interno dei sorgenti del kernel + (o prevenirli) + + Questo documento è vitale per la comprensione della filosifia alla base + dello sviluppo di Linux ed è molto importante per le persone che arrivano + da esperienze con altri Sistemi Operativi. + + :ref:`Documentation/translations/it_IT/admin-guide/security-bugs.rst <it_securitybugs>` + Se ritenete di aver trovato un problema di sicurezza nel kernel Linux, + seguite i passaggi scritti in questo documento per notificarlo agli + sviluppatori del kernel, ed aiutare la risoluzione del problema. + + :ref:`Documentation/translations/it_IT/process/management-style.rst <it_managementstyle>` + Questo documento descrive come i manutentori del kernel Linux operano + e la filosofia comune alla base del loro metodo. Questa è un'importante + lettura per tutti coloro che sono nuovi allo sviluppo del kernel (o per + chi è semplicemente curioso), poiché risolve molti dei più comuni + fraintendimenti e confusioni dovuti al particolare comportamento dei + manutentori del kernel. + + :ref:`Documentation/translations/it_IT/process/stable-kernel-rules.rst <it_stable_kernel_rules>` + Questo file descrive le regole sulle quali vengono basati i rilasci del + kernel, e spiega cosa fare se si vuole che una modifica venga inserita + in uno di questi rilasci. + + :ref:`Documentation/translations/it_IT/process/kernel-docs.rst <it_kernel_docs>` + Una lista di documenti pertinenti allo sviluppo del kernel. + Per favore consultate questa lista se non trovate ciò che cercate nella + documentazione interna del kernel. + + :ref:`Documentation/translations/it_IT/process/applying-patches.rst <it_applying_patches>` + Una buona introduzione che descrivere esattamente cos'è una patch e come + applicarla ai differenti rami di sviluppo del kernel. + +Il kernel inoltre ha un vasto numero di documenti che possono essere +automaticamente generati dal codice sorgente stesso o da file +ReStructuredText (ReST), come questo. Esso include una completa +descrizione dell'API interna del kernel, e le regole su come gestire la +sincronizzazione (locking) correttamente + +Tutte queste tipologie di documenti possono essere generati in PDF o in +HTML utilizzando:: + + make pdfdocs + make htmldocs + +rispettivamente dalla cartella principale dei sorgenti del kernel. + +I documenti che impiegano ReST saranno generati nella cartella +Documentation/output. +Questi posso essere generati anche in formato LaTex e ePub con:: + + make latexdocs + make epubdocs + +Diventare uno sviluppatore del kernel +------------------------------------- +Se non sapete nulla sullo sviluppo del kernel Linux, dovreste dare uno +sguardo al progetto *Linux KernelNewbies*: + + https://kernelnewbies.org + +Esso prevede un'utile lista di discussione dove potete porre più o meno ogni +tipo di quesito relativo ai concetti fondamentali sullo sviluppo del kernel +(assicuratevi di cercare negli archivi, prima di chiedere qualcosa alla +quale è già stata fornita risposta in passato). Esistono inoltre, un canale IRC +che potete usare per formulare domande in tempo reale, e molti documenti utili +che vi faciliteranno nell'apprendimento dello sviluppo del kernel Linux. + +Il sito internet contiene informazioni di base circa l'organizzazione del +codice, sottosistemi e progetti attuali (sia interni che esterni a Linux). +Esso descrive, inoltre, informazioni logistiche di base, riguardanti ad esempio +la compilazione del kernel e l'applicazione di una modifica. + +Se non sapete dove cominciare, ma volete cercare delle attività dalle quali +partire per partecipare alla comunità di sviluppo, andate al progetto Linux +Kernel Janitor's. + + https://kernelnewbies.org/KernelJanitors + +È un buon posto da cui iniziare. Esso presenta una lista di problematiche +relativamente semplici da sistemare e pulire all'interno della sorgente del +kernel Linux. Lavorando con gli sviluppatori incaricati di questo progetto, +imparerete le basi per l'inserimento delle vostre modifiche all'interno dei +sorgenti del kernel Linux, e possibilmente, sarete indirizzati al lavoro +successivo da svolgere, se non ne avrete ancora idea. + +Prima di apportare una qualsiasi modifica al codice del kernel Linux, +è imperativo comprendere come tale codice funziona. A questo scopo, non c'è +nulla di meglio che leggerlo direttamente (la maggior parte dei bit più +complessi sono ben commentati), eventualmente anche con l'aiuto di strumenti +specializzati. Uno degli strumenti che è particolarmente raccomandato è +il progetto Linux Cross-Reference, che è in grado di presentare codice +sorgente in un formato autoreferenziale ed indicizzato. Un eccellente ed +aggiornata fonte di consultazione del codice del kernel la potete trovare qui: + + http://lxr.free-electrons.com/ + + +Il processo di sviluppo +----------------------- +Il processo di sviluppo del kernel Linux si compone di pochi "rami" principali +e di molti altri rami per specifici sottosistemi. Questi rami sono: + + - I sorgenti kernel 4.x + - I sorgenti stabili del kernel 4.x.y -stable + - Le modifiche in 4.x -git + - Sorgenti dei sottosistemi del kernel e le loro modifiche + - Il kernel 4.x -next per test d'integrazione + +I sorgenti kernel 4.x +~~~~~~~~~~~~~~~~~~~~~ + +I kernel 4.x sono amministrati da Linus Torvald, e possono essere trovati +su https://kernel.org nella cartella pub/linux/kernel/v4.x/. Il processo +di sviluppo è il seguente: + + - Non appena un nuovo kernel viene rilasciato si apre una finestra di due + settimane. Durante questo periodo i manutentori possono proporre a Linus + dei grossi cambiamenti; solitamente i cambiamenti che sono già stati + inseriti nel ramo -next del kernel per alcune settimane. Il modo migliore + per sottoporre dei cambiamenti è attraverso git (lo strumento usato per + gestire i sorgenti del kernel, più informazioni sul sito + https://git-scm.com/) ma anche delle patch vanno bene. + + - Al termine delle due settimane un kernel -rc1 viene rilasciato e + l'obbiettivo ora è quello di renderlo il più solido possibile. A questo + punto la maggior parte delle patch dovrebbero correggere un'eventuale + regressione. I bachi che sono sempre esistiti non sono considerabili come + regressioni, quindi inviate questo tipo di cambiamenti solo se sono + importanti. Notate che un intero driver (o filesystem) potrebbe essere + accettato dopo la -rc1 poiché non esistono rischi di una possibile + regressione con tale cambiamento, fintanto che quest'ultimo è + auto-contenuto e non influisce su aree esterne al codice che è stato + aggiunto. git può essere utilizzato per inviare le patch a Linus dopo che + la -rc1 è stata rilasciata, ma è anche necessario inviare le patch ad + una lista di discussione pubblica per un'ulteriore revisione. + + - Una nuova -rc viene rilasciata ogni volta che Linus reputa che gli attuali + sorgenti siano in uno stato di salute ragionevolmente adeguato ai test. + L'obiettivo è quello di rilasciare una nuova -rc ogni settimana. + + - Il processo continua fino a che il kernel è considerato "pronto"; tale + processo dovrebbe durare circa in 6 settimane. + +È utile menzionare quanto scritto da Andrew Morton sulla lista di discussione +kernel-linux in merito ai rilasci del kernel: + + *"Nessuno sa quando un kernel verrà rilasciato, poichè questo è + legato allo stato dei bachi e non ad una cronologia preventiva."* + +I sorgenti stabili del kernel 4.x.y -stable +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +I kernel con versioni in 3-parti sono "kernel stabili". Essi contengono +correzioni critiche relativamente piccole nell'ambito della sicurezza +oppure significative regressioni scoperte in un dato 4.x kernel. + +Questo è il ramo raccomandato per gli utenti che vogliono un kernel recente +e stabile e non sono interessati a dare il proprio contributo alla verifica +delle versioni di sviluppo o sperimentali. + +Se non è disponibile alcun kernel 4.x.y., quello più aggiornato e stabile +sarà il kernel 4.x con la numerazione più alta. + +4.x.y sono amministrati dal gruppo "stable" <stable@vger.kernel.org>, e sono +rilasciati a seconda delle esigenze. Il normale periodo di rilascio è +approssimativamente di due settimane, ma può essere più lungo se non si +verificano problematiche urgenti. Un problema relativo alla sicurezza, invece, +può determinare un rilascio immediato. + +Il file Documentation/process/stable-kernel-rules.rst (nei sorgenti) documenta +quali tipologie di modifiche sono accettate per i sorgenti -stable, e come +avviene il processo di rilascio. + +Le modifiche in 4.x -git +~~~~~~~~~~~~~~~~~~~~~~~~ + +Queste sono istantanee quotidiane del kernel di Linus e sono gestite in +una repositorio git (da qui il nome). Queste modifiche sono solitamente +rilasciate giornalmente e rappresentano l'attuale stato dei sorgenti di +Linus. Queste sono da considerarsi più sperimentali di un -rc in quanto +generate automaticamente senza nemmeno aver dato una rapida occhiata +per verificarne lo stato. + + +Sorgenti dei sottosistemi del kernel e le loro patch +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +I manutentori dei diversi sottosistemi del kernel --- ed anche molti +sviluppatori di sottosistemi --- mostrano il loro attuale stato di sviluppo +nei loro repositori. In questo modo, altri possono vedere cosa succede nelle +diverse parti del kernel. In aree dove lo sviluppo è rapido, potrebbe essere +chiesto ad uno sviluppatore di basare le proprie modifiche su questi repositori +in modo da evitare i conflitti fra le sottomissioni ed altri lavori in corso + +La maggior parte di questi repositori sono git, ma esistono anche altri SCM +in uso, o file di patch pubblicate come una serie quilt. +Gli indirizzi dei repositori di sottosistema sono indicati nel file +MAINTAINERS. Molti di questi posso essere trovati su https://git.kernel.org/. + +Prima che una modifica venga inclusa in questi sottosistemi, sarà soggetta ad +una revisione che inizialmente avviene tramite liste di discussione (vedere la +sezione dedicata qui sotto). Per molti sottosistemi del kernel, tale processo +di revisione è monitorato con lo strumento patchwork. +Patchwork offre un'interfaccia web che mostra le patch pubblicate, inclusi i +commenti o le revisioni fatte, e gli amministratori possono indicare le patch +come "in revisione", "accettate", o "rifiutate". Diversi siti Patchwork sono +elencati al sito https://patchwork.kernel.org/. + +Il kernel 4.x -next per test d'integrazione +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Prima che gli aggiornamenti dei sottosistemi siano accorpati nel ramo +principale 4.x, sarà necessario un test d'integrazione. +A tale scopo, esiste un repositorio speciale di test nel quale virtualmente +tutti i rami dei sottosistemi vengono inclusi su base quotidiana: + + https://git.kernel.org/?p=linux/kernel/git/next/linux-next.git + +In questo modo, i kernel -next offrono uno sguardo riassuntivo su quello che +ci si aspetterà essere nel kernel principale nel successivo periodo +d'incorporazione. +Coloro che vorranno fare dei test d'esecuzione del kernel -next sono più che +benvenuti. + + +Riportare Bug +------------- + +https://bugzilla.kernel.org è dove gli sviluppatori del kernel Linux tracciano +i bachi del kernel. Gli utenti sono incoraggiati nel riportare tutti i bachi +che trovano utilizzando questo strumento. +Per maggiori dettagli su come usare il bugzilla del kernel, guardare: + + https://bugzilla.kernel.org/page.cgi?id=faq.html + +Il file admin-guide/reporting-bugs.rst nella cartella principale del kernel +fornisce un buon modello sul come segnalare un baco nel kernel, e spiega quali +informazioni sono necessarie agli sviluppatori per poter aiutare il +rintracciamento del problema. + +Gestire i rapporti sui bug +-------------------------- + +Uno dei modi migliori per mettere in pratica le vostre capacità di hacking è +quello di riparare bachi riportati da altre persone. Non solo aiuterete a far +diventare il kernel più stabile, ma imparerete a riparare problemi veri dal +mondo ed accrescerete le vostre competenze, e gli altri sviluppatori saranno +al corrente della vostra presenza. Riparare bachi è una delle migliori vie per +acquisire meriti tra gli altri sviluppatori, perchè non a molte persone piace +perdere tempo a sistemare i bachi di altri. + +Per lavorare sui rapporti di bachi già riportati, andate su +https://bugzilla.kernel.org. + +Liste di discussione +-------------------- + +Come descritto in molti dei documenti qui sopra, la maggior parte degli +sviluppatori del kernel partecipano alla lista di discussione Linux Kernel. +I dettagli su come iscriversi e disiscriversi dalla lista possono essere +trovati al sito: + + http://vger.kernel.org/vger-lists.html#linux-kernel + +Ci sono diversi archivi della lista di discussione. Usate un qualsiasi motore +di ricerca per trovarli. Per esempio: + + http://dir.gmane.org/gmane.linux.kernel + +É caldamente consigliata una ricerca in questi archivi sul tema che volete +sollevare, prima di pubblicarlo sulla lista. Molte cose sono già state +discusse in dettaglio e registrate negli archivi della lista di discussione. + +Molti dei sottosistemi del kernel hanno anche una loro lista di discussione +dedicata. Guardate nel file MAINTAINERS per avere una lista delle liste di +discussione e il loro uso. + +Molte di queste liste sono gestite su kernel.org. Per informazioni consultate +la seguente pagina: + + http://vger.kernel.org/vger-lists.html + +Per favore ricordatevi della buona educazione quando utilizzate queste liste. +Sebbene sia un pò dozzinale, il seguente URL contiene alcune semplici linee +guida per interagire con la lista (o con qualsiasi altra lista): + + http://www.albion.com/netiquette/ + +Se diverse persone rispondo alla vostra mail, la lista dei riceventi (copia +conoscenza) potrebbe diventare abbastanza lunga. Non cancellate nessuno dalla +lista di CC: senza un buon motivo, e non rispondete solo all'indirizzo +della lista di discussione. Fateci l'abitudine perché capita spesso di +ricevere la stessa email due volte: una dal mittente ed una dalla lista; e non +cercate di modificarla aggiungendo intestazioni stravaganti, agli altri non +piacerà. + +Ricordate di rimanere sempre in argomento e di mantenere le attribuzioni +delle vostre risposte invariate; mantenete il "John Kernelhacker wrote ...:" +in cima alla vostra replica e aggiungete le vostre risposte fra i singoli +blocchi citati, non scrivete all'inizio dell'email. + +Se aggiungete patch alla vostra mail, assicuratevi che siano del tutto +leggibili come indicato in Documentation/process/submitting-patches.rst. +Gli sviluppatori kernel non vogliono avere a che fare con allegati o patch +compresse; vogliono invece poter commentare le righe dei vostri cambiamenti, +il che può funzionare solo in questo modo. +Assicuratevi di utilizzare un gestore di mail che non alterì gli spazi ed i +caratteri. Un ottimo primo test è quello di inviare a voi stessi una mail e +cercare di sottoporre la vostra stessa patch. Se non funziona, sistemate il +vostro programma di posta, o cambiatelo, finché non funziona. + +Ed infine, per favore ricordatevi di mostrare rispetto per gli altri +sottoscriventi. + +Lavorare con la comunità +------------------------ + +L'obiettivo di questa comunità è quello di fornire il miglior kernel possibile. +Quando inviate una modifica che volete integrare, sarà valutata esclusivamente +dal punto di vista tecnico. Quindi, cosa dovreste aspettarvi? + + - critiche + - commenti + - richieste di cambiamento + - richieste di spiegazioni + - nulla + +Ricordatevi che questo fa parte dell'integrazione della vostra modifica +all'interno del kernel. Dovete essere in grado di accettare le critiche, +valutarle a livello tecnico ed eventualmente rielaborare nuovamente le vostre +modifiche o fornire delle chiare e concise motivazioni per le quali le +modifiche suggerite non dovrebbero essere fatte. +Se non riceverete risposte, aspettate qualche giorno e riprovate ancora, +qualche volta le cose si perdono nell'enorme mucchio di email. + +Cosa non dovreste fare? + + - aspettarvi che la vostra modifica venga accettata senza problemi + - mettervi sulla difensiva + - ignorare i commenti + - sottomettere nuovamente la modifica senza fare nessuno dei cambiamenti + richiesti + +In una comunità che è alla ricerca delle migliori soluzioni tecniche possibili, +ci saranno sempre opinioni differenti sull'utilità di una modifica. +Siate cooperativi e vogliate adattare la vostra idea in modo che sia inserita +nel kernel. O almeno vogliate dimostrare che la vostra idea vale. +Ricordatevi, sbagliare è accettato fintanto che siate disposti a lavorare verso +una soluzione che è corretta. + +È normale che le risposte alla vostra prima modifica possa essere +semplicemente una lista con dozzine di cose che dovreste correggere. +Questo **non** implica che la vostra patch non sarà accettata, e questo +**non** è contro di voi personalmente. +Semplicemente correggete tutte le questioni sollevate contro la vostra modifica +ed inviatela nuovamente. + +Differenze tra la comunità del kernel e le strutture aziendali +-------------------------------------------------------------- + +La comunità del kernel funziona diversamente rispetto a molti ambienti di +sviluppo aziendali. Qui di seguito una lista di cose che potete provare a +fare per evitare problemi: + + Cose da dire riguardanti le modifiche da voi proposte: + + - "Questo risolve più problematiche." + - "Questo elimina 2000 stringhe di codice." + - "Qui una modifica che spiega cosa sto cercando di fare." + - "L'ho testato su 5 diverse architetture.." + - "Qui una serie di piccole modifiche che.." + - "Questo aumenta le prestazioni di macchine standard..." + + Cose che dovreste evitare di dire: + + - "Lo abbiamo fatto in questo modo in AIX/ptx/Solaris, di conseguenza + deve per forza essere giusto..." + - "Ho fatto questo per 20 anni, quindi.." + - "Questo è richiesto dalla mia Azienda per far soldi" + - "Questo è per la linea di prodotti della nostra Azienda" + - "Ecco il mio documento di design di 1000 pagine che descrive ciò che ho + in mente" + - "Ci ho lavorato per 6 mesi..." + - "Ecco una patch da 5000 righe che.." + - "Ho riscritto il pasticcio attuale, ed ecco qua.." + - "Ho una scadenza, e questa modifica ha bisogno di essere approvata ora" + +Un'altra cosa nella quale la comunità del kernel si differenzia dai più +classici ambienti di ingegneria del software è la natura "senza volto" delle +interazioni umane. Uno dei benefici dell'uso delle email e di irc come forma +primordiale di comunicazione è l'assenza di discriminazione basata su genere e +razza. L'ambienti di lavoro Linux accetta donne e minoranze perchè tutto quello +che sei è un indirizzo email. Aiuta anche l'aspetto internazionale nel +livellare il terreno di gioco perchè non è possibile indovinare il genere +basandosi sul nome di una persona. Un uomo può chiamarsi Andrea ed una donna +potrebbe chiamarsi Pat. Gran parte delle donne che hanno lavorato al kernel +Linux e che hanno espresso una personale opinione hanno avuto esperienze +positive. + +La lingua potrebbe essere un ostacolo per quelle persone che non si trovano +a loro agio con l'inglese. Una buona padronanza del linguaggio può essere +necessaria per esporre le proprie idee in maniera appropiata all'interno +delle liste di discussione, quindi è consigliabile che rileggiate le vostre +email prima di inviarle in modo da essere certi che abbiano senso in inglese. + + +Spezzare le vostre modifiche +---------------------------- + +La comunità del kernel Linux non accetta con piacere grossi pezzi di codice +buttati lì tutti in una volta. Le modifiche necessitano di essere +adeguatamente presentate, discusse, e suddivise in parti più piccole ed +indipendenti. Questo è praticamente l'esatto opposto di quello che le +aziende fanno solitamente. La vostra proposta dovrebbe, inoltre, essere +presentata prestissimo nel processo di sviluppo, così che possiate ricevere +un riscontro su quello che state facendo. Lasciate che la comunità +senta che state lavorando con loro, e che non li stiate sfruttando come +discarica per le vostre aggiunte. In ogni caso, non inviate 50 email nello +stesso momento in una lista di discussione, il più delle volte la vostra serie +di modifiche dovrebbe essere più piccola. + +I motivi per i quali dovreste frammentare le cose sono i seguenti: + +1) Piccole modifiche aumentano le probabilità che vengano accettate, + altrimenti richiederebbe troppo tempo o sforzo nel verificarne + la correttezza. Una modifica di 5 righe può essere accettata da un + manutentore con a mala pena una seconda occhiata. Invece, una modifica da + 500 linee può richiedere ore di rilettura per verificarne la correttezza + (il tempo necessario è esponenzialmente proporzionale alla dimensione della + modifica, o giù di lì) + + Piccole modifiche sono inoltre molto facili da debuggare quando qualcosa + non va. È molto più facile annullare le modifiche una per una che + dissezionare una patch molto grande dopo la sua sottomissione (e rompere + qualcosa). + +2) È importante non solo inviare piccole modifiche, ma anche riscriverle e + semplificarle (o più semplicemente ordinarle) prima di sottoporle. + +Qui un'analogia dello sviluppatore kernel Al Viro: + + *"Pensate ad un insegnante di matematica che corregge il compito + di uno studente (di matematica). L'insegnante non vuole vedere le + prove e gli errori commessi dallo studente prima che arrivi alla + soluzione. Vuole vedere la risposta più pulita ed elegante + possibile. Un buono studente lo sa, e non presenterebbe mai le + proprie bozze prima prima della soluzione finale"* + + *"Lo stesso vale per lo sviluppo del kernel. I manutentori ed i + revisori non vogliono vedere il procedimento che sta dietro al + problema che uno sta risolvendo. Vogliono vedere una soluzione + semplice ed elegante."* + +Può essere una vera sfida il saper mantenere l'equilibrio fra una presentazione +elegante della vostra soluzione, lavorare insieme ad una comunità e dibattere +su un lavoro incompleto. Pertanto è bene entrare presto nel processo di +revisione per migliorare il vostro lavoro, ma anche per riuscire a tenere le +vostre modifiche in pezzettini che potrebbero essere già accettate, nonostante +la vostra intera attività non lo sia ancora. + +In fine, rendetevi conto che non è accettabile inviare delle modifiche +incomplete con la promessa che saranno "sistemate dopo". + + +Giustificare le vostre modifiche +-------------------------------- + +Insieme alla frammentazione delle vostre modifiche, è altrettanto importante +permettere alla comunità Linux di capire perché dovrebbero accettarle. +Nuove funzionalità devono essere motivate come necessarie ed utili. + + +Documentare le vostre modifiche +------------------------------- + +Quando inviate le vostre modifiche, fate particolare attenzione a quello che +scrivete nella vostra email. Questa diventerà il *ChangeLog* per la modifica, +e sarà visibile a tutti per sempre. Dovrebbe descrivere la modifica nella sua +interezza, contenendo: + + - perchè la modifica è necessaria + - l'approccio d'insieme alla patch + - dettagli supplementari + - risultati dei test + +Per maggiori dettagli su come tutto ciò dovrebbe apparire, riferitevi alla +sezione ChangeLog del documento: + + "The Perfect Patch" + http://www.ozlabs.org/~akpm/stuff/tpp.txt + +A volte tutto questo è difficile da realizzare. Il perfezionamento di queste +pratiche può richiedere anni (eventualmente). È un processo continuo di +miglioramento che richiede molta pazienza e determinazione. Ma non mollate, +si può fare. Molti lo hanno fatto prima, ed ognuno ha dovuto iniziare dove +siete voi ora. + + + + +---------- + +Grazie a Paolo Ciarrocchi che ha permesso che la sezione "Development Process" +(https://lwn.net/Articles/94386/) fosse basata sui testi da lui scritti, ed a +Randy Dunlap e Gerrit Huizenga per la lista di cose che dovreste e non +dovreste dire. Grazie anche a Pat Mochel, Hanna Linder, Randy Dunlap, +Kay Sievers, Vojtech Pavlik, Jan Kara, Josh Boyer, Kees Cook, Andrew Morton, +Andi Kleen, Vadim Lobanov, Jesper Juhl, Adrian Bunk, Keri Harris, Frans Pop, +David A. Wheeler, Junio Hamano, Michael Kerrisk, e Alex Shepard per le +loro revisioni, commenti e contributi. Senza il loro aiuto, questo documento +non sarebbe stato possibile. + +Manutentore: Greg Kroah-Hartman <greg@kroah.com> diff --git a/Documentation/translations/it_IT/process/index.rst b/Documentation/translations/it_IT/process/index.rst new file mode 100644 index 000000000000..2eda85d5cd1e --- /dev/null +++ b/Documentation/translations/it_IT/process/index.rst @@ -0,0 +1,67 @@ +.. raw:: latex + + \renewcommand\thesection* + \renewcommand\thesubsection* + +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/index.rst <process_index>` +:Translator: Federico Vaga <federico.vaga@vaga.pv.it> + +.. _it_process_index: + +Lavorare con la comunità di sviluppo del kernel +=============================================== + +Quindi volete diventare sviluppatori del kernel? Benvenuti! C'è molto da +imparare sul lato tecnico del kernel, ma è anche importante capire come +funziona la nostra comunità. Leggere questi documenti renderà più facile +l'accettazione delle vostre modifiche con il minimo sforzo. + +Di seguito le guide che ogni sviluppatore dovrebbe leggere. + +.. toctree:: + :maxdepth: 1 + + howto + code-of-conduct + development-process + submitting-patches + coding-style + maintainer-pgp-guide + email-clients + kernel-enforcement-statement + kernel-driver-statement + +Poi ci sono altre guide sulla comunità che sono di interesse per molti +degli sviluppatori: + +.. toctree:: + :maxdepth: 1 + + changes + submitting-drivers + stable-api-nonsense + management-style + stable-kernel-rules + submit-checklist + kernel-docs + +Ed infine, qui ci sono alcune guide più tecniche che son state messe qua solo +perché non si è trovato un posto migliore. + +.. toctree:: + :maxdepth: 1 + + applying-patches + adding-syscalls + magic-number + volatile-considered-harmful + clang-format + +.. only:: subproject and html + + Indices + ======= + + * :ref:`genindex` diff --git a/Documentation/translations/it_IT/process/kernel-docs.rst b/Documentation/translations/it_IT/process/kernel-docs.rst new file mode 100644 index 000000000000..7bd70d661737 --- /dev/null +++ b/Documentation/translations/it_IT/process/kernel-docs.rst @@ -0,0 +1,13 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/kernel-docs.rst <kernel_docs>` + + +.. _it_kernel_docs: + +Indice di documenti per le persone interessate a capire e/o scrivere per il kernel Linux +======================================================================================== + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/kernel-driver-statement.rst b/Documentation/translations/it_IT/process/kernel-driver-statement.rst new file mode 100644 index 000000000000..f016a75a9d6e --- /dev/null +++ b/Documentation/translations/it_IT/process/kernel-driver-statement.rst @@ -0,0 +1,211 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/kernel-driver-statement.rst <process_statement_driver>` +:Translator: Federico Vaga <federico.vaga@vaga.pv.it> + +.. _it_process_statement_driver: + +Dichiarazioni sui driver per il kernel +====================================== + +Presa di posizione sui moduli per il kernel Linux +------------------------------------------------- + +Noi, i sottoscritti sviluppatori del kernel, consideriamo pericoloso +o indesiderato qualsiasi modulo o driver per il kernel Linux di tipo +*a sorgenti chiusi* (*closed-source*). Ripetutamente, li abbiamo +trovati deleteri per gli utenti Linux, le aziende, ed in generale +l'ecosistema Linux. Questi moduli impediscono l'apertura, la stabilità, +la flessibilità, e la manutenibilità del modello di sviluppo di Linux +e impediscono ai loro utenti di beneficiare dell'esperienza dalla +comunità Linux. I fornitori che distribuiscono codice a sorgenti chiusi +obbligano i propri utenti a rinunciare ai principali vantaggi di Linux +o a cercarsi nuovi fornitori. +Perciò, al fine di sfruttare i vantaggi che codice aperto ha da offrire, +come l'abbattimento dei costi e un supporto condiviso, spingiamo i +fornitori ad adottare una politica di supporto ai loro clienti Linux +che preveda il rilascio dei sorgenti per il kernel. + +Parliamo solo per noi stessi, e non per una qualsiasi azienda per la +quale lavoriamo oggi, o abbiamo lavorato in passato, o lavoreremo in +futuro. + + + - Dave Airlie + - Nick Andrew + - Jens Axboe + - Ralf Baechle + - Felipe Balbi + - Ohad Ben-Cohen + - Muli Ben-Yehuda + - Jiri Benc + - Arnd Bergmann + - Thomas Bogendoerfer + - Vitaly Bordug + - James Bottomley + - Josh Boyer + - Neil Brown + - Mark Brown + - David Brownell + - Michael Buesch + - Franck Bui-Huu + - Adrian Bunk + - François Cami + - Ralph Campbell + - Luiz Fernando N. Capitulino + - Mauro Carvalho Chehab + - Denis Cheng + - Jonathan Corbet + - Glauber Costa + - Alan Cox + - Magnus Damm + - Ahmed S. Darwish + - Robert P. J. Day + - Hans de Goede + - Arnaldo Carvalho de Melo + - Helge Deller + - Jean Delvare + - Mathieu Desnoyers + - Sven-Thorsten Dietrich + - Alexey Dobriyan + - Daniel Drake + - Alex Dubov + - Randy Dunlap + - Michael Ellerman + - Pekka Enberg + - Jan Engelhardt + - Mark Fasheh + - J. Bruce Fields + - Larry Finger + - Jeremy Fitzhardinge + - Mike Frysinger + - Kumar Gala + - Robin Getz + - Liam Girdwood + - Jan-Benedict Glaw + - Thomas Gleixner + - Brice Goglin + - Cyrill Gorcunov + - Andy Gospodarek + - Thomas Graf + - Krzysztof Halasa + - Harvey Harrison + - Stephen Hemminger + - Michael Hennerich + - Tejun Heo + - Benjamin Herrenschmidt + - Kristian Høgsberg + - Henrique de Moraes Holschuh + - Marcel Holtmann + - Mike Isely + - Takashi Iwai + - Olof Johansson + - Dave Jones + - Jesper Juhl + - Matthias Kaehlcke + - Kenji Kaneshige + - Jan Kara + - Jeremy Kerr + - Russell King + - Olaf Kirch + - Roel Kluin + - Hans-Jürgen Koch + - Auke Kok + - Peter Korsgaard + - Jiri Kosina + - Aaro Koskinen + - Mariusz Kozlowski + - Greg Kroah-Hartman + - Michael Krufky + - Aneesh Kumar + - Clemens Ladisch + - Christoph Lameter + - Gunnar Larisch + - Anders Larsen + - Grant Likely + - John W. Linville + - Yinghai Lu + - Tony Luck + - Pavel Machek + - Matt Mackall + - Paul Mackerras + - Roland McGrath + - Patrick McHardy + - Kyle McMartin + - Paul Menage + - Thierry Merle + - Eric Miao + - Akinobu Mita + - Ingo Molnar + - James Morris + - Andrew Morton + - Paul Mundt + - Oleg Nesterov + - Luca Olivetti + - S.Çağlar Onur + - Pierre Ossman + - Keith Owens + - Venkatesh Pallipadi + - Nick Piggin + - Nicolas Pitre + - Evgeniy Polyakov + - Richard Purdie + - Mike Rapoport + - Sam Ravnborg + - Gerrit Renker + - Stefan Richter + - David Rientjes + - Luis R. Rodriguez + - Stefan Roese + - Francois Romieu + - Rami Rosen + - Stephen Rothwell + - Maciej W. Rozycki + - Mark Salyzyn + - Yoshinori Sato + - Deepak Saxena + - Holger Schurig + - Amit Shah + - Yoshihiro Shimoda + - Sergei Shtylyov + - Kay Sievers + - Sebastian Siewior + - Rik Snel + - Jes Sorensen + - Alexey Starikovskiy + - Alan Stern + - Timur Tabi + - Hirokazu Takata + - Eliezer Tamir + - Eugene Teo + - Doug Thompson + - FUJITA Tomonori + - Dmitry Torokhov + - Marcelo Tosatti + - Steven Toth + - Theodore Tso + - Matthias Urlichs + - Geert Uytterhoeven + - Arjan van de Ven + - Ivo van Doorn + - Rik van Riel + - Wim Van Sebroeck + - Hans Verkuil + - Horst H. von Brand + - Dmitri Vorobiev + - Anton Vorontsov + - Daniel Walker + - Johannes Weiner + - Harald Welte + - Matthew Wilcox + - Dan J. Williams + - Darrick J. Wong + - David Woodhouse + - Chris Wright + - Bryan Wu + - Rafael J. Wysocki + - Herbert Xu + - Vlad Yasevich + - Peter Zijlstra + - Bartlomiej Zolnierkiewicz + diff --git a/Documentation/translations/it_IT/process/kernel-enforcement-statement.rst b/Documentation/translations/it_IT/process/kernel-enforcement-statement.rst new file mode 100644 index 000000000000..4ddf5a35b270 --- /dev/null +++ b/Documentation/translations/it_IT/process/kernel-enforcement-statement.rst @@ -0,0 +1,13 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/kernel-enforcement-statement.rst <process_statement_kernel>` + + +.. _it_process_statement_kernel: + +Applicazione della licenza sul kernel Linux +=========================================== + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/magic-number.rst b/Documentation/translations/it_IT/process/magic-number.rst new file mode 100644 index 000000000000..5281d53e57ee --- /dev/null +++ b/Documentation/translations/it_IT/process/magic-number.rst @@ -0,0 +1,170 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/magic-numbers.rst <magicnumbers>` +:Translator: Federico Vaga <federico.vaga@vaga.pv.it> + +.. _it_magicnumbers: + +I numeri magici di Linux +======================== + +Questo documento è un registro dei numeri magici in uso. Quando +aggiungete un numero magico ad una struttura, dovreste aggiungerlo anche +a questo documento; la cosa migliore è che tutti i numeri magici usati +dalle varie strutture siano unici. + +È **davvero** un'ottima idea proteggere le strutture dati del kernel con +dei numeri magici. Questo vi permette in fase d'esecuzione di (a) verificare +se una struttura è stata malmenata, o (b) avete passato a una procedura la +struttura errata. Quest'ultimo è molto utile - particolarmente quando si passa +una struttura dati tramite un puntatore void \*. Il codice tty, per esempio, +effettua questa operazione con regolarità passando avanti e indietro le +strutture specifiche per driver e discipline. + +Per utilizzare un numero magico, dovete dichiararlo all'inizio della struttura +dati, come di seguito:: + + struct tty_ldisc { + int magic; + ... + }; + +Per favore, seguite questa direttiva quando aggiungerete migliorie al kernel! +Mi ha risparmiato un numero illimitato di ore di debug, specialmente nei casi +più ostici dove si è andati oltre la dimensione di un vettore e la struttura +dati che lo seguiva in memoria è stata sovrascritta. Seguendo questa +direttiva, questi casi vengono identificati velocemente e in sicurezza. + +Registro dei cambiamenti:: + + Theodore Ts'o + 31 Mar 94 + + La tabella magica è aggiornata a Linux 2.1.55. + + Michael Chastain + <mailto:mec@shout.net> + 22 Sep 1997 + + Ora dovrebbe essere aggiornata a Linux 2.1.112. Dato che + siamo in un momento di congelamento delle funzionalità + (*feature freeze*) è improbabile che qualcosa cambi prima + della versione 2.2.x. Le righe sono ordinate secondo il + campo numero. + + Krzysztof G. Baranowski + <mailto: kgb@knm.org.pl> + 29 Jul 1998 + + Aggiornamento della tabella a Linux 2.5.45. Giusti nel congelamento + delle funzionalità ma è comunque possibile che qualche nuovo + numero magico s'intrufoli prima del kernel 2.6.x. + + Petr Baudis + <pasky@ucw.cz> + 03 Nov 2002 + + Aggiornamento della tabella magica a Linux 2.5.74. + + Fabian Frederick + <ffrederick@users.sourceforge.net> + 09 Jul 2003 + + +===================== ================ ======================== ========================================== +Nome magico Numero Struttura File +===================== ================ ======================== ========================================== +PG_MAGIC 'P' pg_{read,write}_hdr ``include/linux/pg.h`` +CMAGIC 0x0111 user ``include/linux/a.out.h`` +MKISS_DRIVER_MAGIC 0x04bf mkiss_channel ``drivers/net/mkiss.h`` +HDLC_MAGIC 0x239e n_hdlc ``drivers/char/n_hdlc.c`` +APM_BIOS_MAGIC 0x4101 apm_user ``arch/x86/kernel/apm_32.c`` +CYCLADES_MAGIC 0x4359 cyclades_port ``include/linux/cyclades.h`` +DB_MAGIC 0x4442 fc_info ``drivers/net/iph5526_novram.c`` +DL_MAGIC 0x444d fc_info ``drivers/net/iph5526_novram.c`` +FASYNC_MAGIC 0x4601 fasync_struct ``include/linux/fs.h`` +FF_MAGIC 0x4646 fc_info ``drivers/net/iph5526_novram.c`` +ISICOM_MAGIC 0x4d54 isi_port ``include/linux/isicom.h`` +PTY_MAGIC 0x5001 ``drivers/char/pty.c`` +PPP_MAGIC 0x5002 ppp ``include/linux/if_pppvar.h`` +SERIAL_MAGIC 0x5301 async_struct ``include/linux/serial.h`` +SSTATE_MAGIC 0x5302 serial_state ``include/linux/serial.h`` +SLIP_MAGIC 0x5302 slip ``drivers/net/slip.h`` +STRIP_MAGIC 0x5303 strip ``drivers/net/strip.c`` +X25_ASY_MAGIC 0x5303 x25_asy ``drivers/net/x25_asy.h`` +SIXPACK_MAGIC 0x5304 sixpack ``drivers/net/hamradio/6pack.h`` +AX25_MAGIC 0x5316 ax_disp ``drivers/net/mkiss.h`` +TTY_MAGIC 0x5401 tty_struct ``include/linux/tty.h`` +MGSL_MAGIC 0x5401 mgsl_info ``drivers/char/synclink.c`` +TTY_DRIVER_MAGIC 0x5402 tty_driver ``include/linux/tty_driver.h`` +MGSLPC_MAGIC 0x5402 mgslpc_info ``drivers/char/pcmcia/synclink_cs.c`` +TTY_LDISC_MAGIC 0x5403 tty_ldisc ``include/linux/tty_ldisc.h`` +USB_SERIAL_MAGIC 0x6702 usb_serial ``drivers/usb/serial/usb-serial.h`` +FULL_DUPLEX_MAGIC 0x6969 ``drivers/net/ethernet/dec/tulip/de2104x.c`` +USB_BLUETOOTH_MAGIC 0x6d02 usb_bluetooth ``drivers/usb/class/bluetty.c`` +RFCOMM_TTY_MAGIC 0x6d02 ``net/bluetooth/rfcomm/tty.c`` +USB_SERIAL_PORT_MAGIC 0x7301 usb_serial_port ``drivers/usb/serial/usb-serial.h`` +CG_MAGIC 0x00090255 ufs_cylinder_group ``include/linux/ufs_fs.h`` +RPORT_MAGIC 0x00525001 r_port ``drivers/char/rocket_int.h`` +LSEMAGIC 0x05091998 lse ``drivers/fc4/fc.c`` +GDTIOCTL_MAGIC 0x06030f07 gdth_iowr_str ``drivers/scsi/gdth_ioctl.h`` +RIEBL_MAGIC 0x09051990 ``drivers/net/atarilance.c`` +NBD_REQUEST_MAGIC 0x12560953 nbd_request ``include/linux/nbd.h`` +RED_MAGIC2 0x170fc2a5 (any) ``mm/slab.c`` +BAYCOM_MAGIC 0x19730510 baycom_state ``drivers/net/baycom_epp.c`` +ISDN_X25IFACE_MAGIC 0x1e75a2b9 isdn_x25iface_proto_data ``drivers/isdn/isdn_x25iface.h`` +ECP_MAGIC 0x21504345 cdkecpsig ``include/linux/cdk.h`` +LSOMAGIC 0x27091997 lso ``drivers/fc4/fc.c`` +LSMAGIC 0x2a3b4d2a ls ``drivers/fc4/fc.c`` +WANPIPE_MAGIC 0x414C4453 sdla_{dump,exec} ``include/linux/wanpipe.h`` +CS_CARD_MAGIC 0x43525553 cs_card ``sound/oss/cs46xx.c`` +LABELCL_MAGIC 0x4857434c labelcl_info_s ``include/asm/ia64/sn/labelcl.h`` +ISDN_ASYNC_MAGIC 0x49344C01 modem_info ``include/linux/isdn.h`` +CTC_ASYNC_MAGIC 0x49344C01 ctc_tty_info ``drivers/s390/net/ctctty.c`` +ISDN_NET_MAGIC 0x49344C02 isdn_net_local_s ``drivers/isdn/i4l/isdn_net_lib.h`` +SAVEKMSG_MAGIC2 0x4B4D5347 savekmsg ``arch/*/amiga/config.c`` +CS_STATE_MAGIC 0x4c4f4749 cs_state ``sound/oss/cs46xx.c`` +SLAB_C_MAGIC 0x4f17a36d kmem_cache ``mm/slab.c`` +COW_MAGIC 0x4f4f4f4d cow_header_v1 ``arch/um/drivers/ubd_user.c`` +I810_CARD_MAGIC 0x5072696E i810_card ``sound/oss/i810_audio.c`` +TRIDENT_CARD_MAGIC 0x5072696E trident_card ``sound/oss/trident.c`` +ROUTER_MAGIC 0x524d4157 wan_device [in ``wanrouter.h`` pre 3.9] +SAVEKMSG_MAGIC1 0x53415645 savekmsg ``arch/*/amiga/config.c`` +GDA_MAGIC 0x58464552 gda ``arch/mips/include/asm/sn/gda.h`` +RED_MAGIC1 0x5a2cf071 (any) ``mm/slab.c`` +EEPROM_MAGIC_VALUE 0x5ab478d2 lanai_dev ``drivers/atm/lanai.c`` +HDLCDRV_MAGIC 0x5ac6e778 hdlcdrv_state ``include/linux/hdlcdrv.h`` +PCXX_MAGIC 0x5c6df104 channel ``drivers/char/pcxx.h`` +KV_MAGIC 0x5f4b565f kernel_vars_s ``arch/mips/include/asm/sn/klkernvars.h`` +I810_STATE_MAGIC 0x63657373 i810_state ``sound/oss/i810_audio.c`` +TRIDENT_STATE_MAGIC 0x63657373 trient_state ``sound/oss/trident.c`` +M3_CARD_MAGIC 0x646e6f50 m3_card ``sound/oss/maestro3.c`` +FW_HEADER_MAGIC 0x65726F66 fw_header ``drivers/atm/fore200e.h`` +SLOT_MAGIC 0x67267321 slot ``drivers/hotplug/cpqphp.h`` +SLOT_MAGIC 0x67267322 slot ``drivers/hotplug/acpiphp.h`` +LO_MAGIC 0x68797548 nbd_device ``include/linux/nbd.h`` +OPROFILE_MAGIC 0x6f70726f super_block ``drivers/oprofile/oprofilefs.h`` +M3_STATE_MAGIC 0x734d724d m3_state ``sound/oss/maestro3.c`` +VMALLOC_MAGIC 0x87654320 snd_alloc_track ``sound/core/memory.c`` +KMALLOC_MAGIC 0x87654321 snd_alloc_track ``sound/core/memory.c`` +PWC_MAGIC 0x89DC10AB pwc_device ``drivers/usb/media/pwc.h`` +NBD_REPLY_MAGIC 0x96744668 nbd_reply ``include/linux/nbd.h`` +ENI155_MAGIC 0xa54b872d midway_eprom ``drivers/atm/eni.h`` +CODA_MAGIC 0xC0DAC0DA coda_file_info ``fs/coda/coda_fs_i.h`` +DPMEM_MAGIC 0xc0ffee11 gdt_pci_sram ``drivers/scsi/gdth.h`` +YAM_MAGIC 0xF10A7654 yam_port ``drivers/net/hamradio/yam.c`` +CCB_MAGIC 0xf2691ad2 ccb ``drivers/scsi/ncr53c8xx.c`` +QUEUE_MAGIC_FREE 0xf7e1c9a3 queue_entry ``drivers/scsi/arm/queue.c`` +QUEUE_MAGIC_USED 0xf7e1cc33 queue_entry ``drivers/scsi/arm/queue.c`` +HTB_CMAGIC 0xFEFAFEF1 htb_class ``net/sched/sch_htb.c`` +NMI_MAGIC 0x48414d4d455201 nmi_s ``arch/mips/include/asm/sn/nmi.h`` +===================== ================ ======================== ========================================== + +Da notare che ci sono anche dei numeri magici specifici per driver nel +*sound memory management*. Consultate ``include/sound/sndmagic.h`` per una +lista completa. Molti driver audio OSS hanno i loro numeri magici costruiti a +partire dall'identificativo PCI della scheda audio - nemmeno questi sono +elencati in questo file. + +Il file-system HFS è un altro grande utilizzatore di numeri magici - potete +trovarli qui ``fs/hfs/hfs.h``. diff --git a/Documentation/translations/it_IT/process/maintainer-pgp-guide.rst b/Documentation/translations/it_IT/process/maintainer-pgp-guide.rst new file mode 100644 index 000000000000..24a133f0a51d --- /dev/null +++ b/Documentation/translations/it_IT/process/maintainer-pgp-guide.rst @@ -0,0 +1,13 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/maintainer-pgp-guide.rst <pgpguide>` + +.. _it_pgpguide: + +======================================== +Guida a PGP per i manutentori del kernel +======================================== + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/management-style.rst b/Documentation/translations/it_IT/process/management-style.rst new file mode 100644 index 000000000000..07e68bfb8402 --- /dev/null +++ b/Documentation/translations/it_IT/process/management-style.rst @@ -0,0 +1,12 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/management-style.rst <managementstyle>` + +.. _it_managementstyle: + +Tipo di gestione del kernel Linux +================================= + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/stable-api-nonsense.rst b/Documentation/translations/it_IT/process/stable-api-nonsense.rst new file mode 100644 index 000000000000..d4fa4abf8dd3 --- /dev/null +++ b/Documentation/translations/it_IT/process/stable-api-nonsense.rst @@ -0,0 +1,13 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/stable-api-nonsense.rst <stable_api_nonsense>` + + +.. _it_stable_api_nonsense: + +L'interfaccia dei driver per il kernel Linux +============================================ + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/stable-kernel-rules.rst b/Documentation/translations/it_IT/process/stable-kernel-rules.rst new file mode 100644 index 000000000000..6fa5ce9c3572 --- /dev/null +++ b/Documentation/translations/it_IT/process/stable-kernel-rules.rst @@ -0,0 +1,12 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/stable-kernel-rules.rst <stable_kernel_rules>` + +.. _it_stable_kernel_rules: + +Tutto quello che volevate sapere sui rilasci -stable di Linux +============================================================== + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/submit-checklist.rst b/Documentation/translations/it_IT/process/submit-checklist.rst new file mode 100644 index 000000000000..b6b4dd94a660 --- /dev/null +++ b/Documentation/translations/it_IT/process/submit-checklist.rst @@ -0,0 +1,12 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/submit-checklist.rst <submitchecklist>` + +.. _it_submitchecklist: + +Lista delle cose da fare per inviare una modifica al kernel Linux +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/submitting-drivers.rst b/Documentation/translations/it_IT/process/submitting-drivers.rst new file mode 100644 index 000000000000..16df950ef808 --- /dev/null +++ b/Documentation/translations/it_IT/process/submitting-drivers.rst @@ -0,0 +1,12 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/submitting-drivers.rst <submittingdrivers>` + +.. _it_submittingdrivers: + +Sottomettere driver per il kernel Linux +======================================= + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/submitting-patches.rst b/Documentation/translations/it_IT/process/submitting-patches.rst new file mode 100644 index 000000000000..d633775ed556 --- /dev/null +++ b/Documentation/translations/it_IT/process/submitting-patches.rst @@ -0,0 +1,13 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/submitting-patches.rst <submittingpatches>` + + +.. _it_submittingpatches: + +Sottomettere modifiche: la guida essenziale per vedere il vostro codice nel kernel +================================================================================== + +.. warning:: + + TODO ancora da tradurre diff --git a/Documentation/translations/it_IT/process/volatile-considered-harmful.rst b/Documentation/translations/it_IT/process/volatile-considered-harmful.rst new file mode 100644 index 000000000000..efc640cac596 --- /dev/null +++ b/Documentation/translations/it_IT/process/volatile-considered-harmful.rst @@ -0,0 +1,134 @@ +.. include:: ../disclaimer-ita.rst + +:Original: :ref:`Documentation/process/volatile-considered-harmful.rst <volatile_considered_harmful>` +:Translator: Federico Vaga <federico.vaga@vaga.pv.it> + +.. _it_volatile_considered_harmful: + +Perché la parola chiave "volatile" non dovrebbe essere usata +------------------------------------------------------------ + +Spesso i programmatori C considerano volatili quelle variabili che potrebbero +essere cambiate al di fuori dal thread di esecuzione corrente; come risultato, +a volte saranno tentati dall'utilizzare *volatile* nel kernel per le +strutture dati condivise. In altre parole, gli è stato insegnato ad usare +*volatile* come una variabile atomica di facile utilizzo, ma non è così. +L'uso di *volatile* nel kernel non è quasi mai corretto; questo documento ne +descrive le ragioni. + +Il punto chiave da capire su *volatile* è che il suo scopo è quello di +sopprimere le ottimizzazioni, che non è quasi mai quello che si vuole. +Nel kernel si devono proteggere le strutture dati condivise contro accessi +concorrenti e indesiderati: questa è un'attività completamente diversa. +Il processo di protezione contro gli accessi concorrenti indesiderati eviterà +anche la maggior parte dei problemi relativi all'ottimizzazione in modo più +efficiente. + +Come *volatile*, le primitive del kernel che rendono sicuro l'accesso ai dati +(spinlock, mutex, barriere di sincronizzazione, ecc) sono progettate per +prevenire le ottimizzazioni indesiderate. Se vengono usate opportunamente, +non ci sarà bisogno di utilizzare *volatile*. Se vi sembra che *volatile* sia +comunque necessario, ci dev'essere quasi sicuramente un baco da qualche parte. +In un pezzo di codice kernel scritto a dovere, *volatile* può solo servire a +rallentare le cose. + +Considerate questo tipico blocco di codice kernel:: + + spin_lock(&the_lock); + do_something_on(&shared_data); + do_something_else_with(&shared_data); + spin_unlock(&the_lock); + +Se tutto il codice seguisse le regole di sincronizzazione, il valore di un +dato condiviso non potrebbe cambiare inaspettatamente mentre si trattiene un +lock. Un qualsiasi altro blocco di codice che vorrà usare quel dato rimarrà +in attesa del lock. Gli spinlock agiscono come barriere di sincronizzazione +- sono stati esplicitamente scritti per agire così - il che significa che gli +accessi al dato condiviso non saranno ottimizzati. Quindi il compilatore +potrebbe pensare di sapere cosa ci sarà nel dato condiviso ma la chiamata +spin_lock(), che agisce come una barriera di sincronizzazione, gli imporrà di +dimenticarsi tutto ciò che sapeva su di esso. + +Se il dato condiviso fosse stato dichiarato come *volatile*, la +sincronizzazione rimarrebbe comunque necessaria. Ma verrà impedito al +compilatore di ottimizzare gli accessi al dato anche _dentro_ alla sezione +critica, dove sappiamo che in realtà nessun altro può accedervi. Mentre si +trattiene un lock, il dato condiviso non è *volatile*. Quando si ha a che +fare con dei dati condivisi, un'opportuna sincronizzazione rende inutile +l'uso di *volatile* - anzi potenzialmente dannoso. + +L'uso di *volatile* fu originalmente pensato per l'accesso ai registri di I/O +mappati in memoria. All'interno del kernel, l'accesso ai registri, dovrebbe +essere protetto dai lock, ma si potrebbe anche desiderare che il compilatore +non "ottimizzi" l'accesso ai registri all'interno di una sezione critica. +Ma, all'interno del kernel, l'accesso alla memoria di I/O viene sempre fatto +attraverso funzioni d'accesso; accedere alla memoria di I/O direttamente +con i puntatori è sconsigliato e non funziona su tutte le architetture. +Queste funzioni d'accesso sono scritte per evitare ottimizzazioni indesiderate, +quindi, di nuovo, *volatile* è inutile. + +Un'altra situazione dove qualcuno potrebbe essere tentato dall'uso di +*volatile*, è nel caso in cui il processore è in un'attesa attiva sul valore +di una variabile. Il modo giusto di fare questo tipo di attesa è il seguente:: + + while (my_variable != what_i_want) + cpu_relax(); + +La chiamata cpu_relax() può ridurre il consumo di energia del processore +o cedere il passo ad un processore hyperthreaded gemello; funziona anche come +una barriera per il compilatore, quindi, ancora una volta, *volatile* non è +necessario. Ovviamente, tanto per puntualizzare, le attese attive sono +generalmente un atto antisociale. + +Ci sono comunque alcune rare situazioni dove l'uso di *volatile* nel kernel +ha senso: + + - Le funzioni d'accesso sopracitate potrebbero usare *volatile* su quelle + architetture che supportano l'accesso diretto alla memoria di I/O. + In pratica, ogni chiamata ad una funzione d'accesso diventa una piccola + sezione critica a se stante, e garantisce che l'accesso avvenga secondo + le aspettative del programmatore. + + - I codice *inline assembly* che fa cambiamenti nella memoria, ma che non + ha altri effetti espliciti, rischia di essere rimosso da GCC. Aggiungere + la parola chiave *volatile* a questo codice ne previene la rimozione. + + - La variabile jiffies è speciale in quanto assume un valore diverso ogni + volta che viene letta ma può essere lette senza alcuna sincronizzazione. + Quindi jiffies può essere *volatile*, ma l'aggiunta ad altre variabili di + questo è sconsigliata. Jiffies è considerata uno "stupido retaggio" + (parole di Linus) in questo contesto; correggerla non ne varrebbe la pena e + causerebbe più problemi. + + - I puntatori a delle strutture dati in una memoria coerente che potrebbe + essere modificata da dispositivi di I/O può, a volte, essere legittimamente + *volatile*. Un esempio pratico può essere quello di un adattatore di rete + che utilizza un puntatore ad un buffer circolare, questo viene cambiato + dall'adattatore per indicare quali descrittori sono stati processati. + +Per la maggior parte del codice, nessuna delle giustificazioni sopracitate può +essere considerata. Di conseguenza, l'uso di *volatile* è probabile che venga +visto come un baco e porterà a verifiche aggiuntive. Gli sviluppatori tentati +dall'uso di *volatile* dovrebbero fermarsi e pensare a cosa vogliono davvero +ottenere. + +Le modifiche che rimuovono variabili *volatile* sono generalmente ben accette +- purché accompagnate da una giustificazione che dimostri che i problemi di +concorrenza siano stati opportunamente considerati. + +Riferimenti +=========== + +[1] http://lwn.net/Articles/233481/ + +[2] http://lwn.net/Articles/233482/ + +Crediti +======= + +Impulso e ricerca originale di Randy Dunlap + +Scritto da Jonathan Corbet + +Migliorato dai commenti di Satyam Sharma, Johannes Stezenbach, Jesper +Juhl, Heikki Orsila, H. Peter Anvin, Philipp Hahn, e Stefan Richter. diff --git a/Documentation/usb/authorization.txt b/Documentation/usb/authorization.txt index c7e985f05d8f..f901ec77439c 100644 --- a/Documentation/usb/authorization.txt +++ b/Documentation/usb/authorization.txt @@ -119,5 +119,5 @@ If a deauthorized interface will be authorized so the driver probing must be triggered manually by writing INTERFACE to /sys/bus/usb/drivers_probe For drivers that need multiple interfaces all needed interfaces should be -authroized first. After that the drivers should be probed. +authorized first. After that the drivers should be probed. This avoids side effects. diff --git a/Documentation/userspace-api/seccomp_filter.rst b/Documentation/userspace-api/seccomp_filter.rst index 82a468bc7560..b1b846d8a094 100644 --- a/Documentation/userspace-api/seccomp_filter.rst +++ b/Documentation/userspace-api/seccomp_filter.rst @@ -122,6 +122,11 @@ In precedence order, they are: Results in the lower 16-bits of the return value being passed to userland as the errno without executing the system call. +``SECCOMP_RET_USER_NOTIF``: + Results in a ``struct seccomp_notif`` message sent on the userspace + notification fd, if it is attached, or ``-ENOSYS`` if it is not. See below + on discussion of how to handle user notifications. + ``SECCOMP_RET_TRACE``: When returned, this value will cause the kernel to attempt to notify a ``ptrace()``-based tracer prior to executing the system @@ -183,6 +188,85 @@ The ``samples/seccomp/`` directory contains both an x86-specific example and a more generic example of a higher level macro interface for BPF program generation. +Userspace Notification +====================== + +The ``SECCOMP_RET_USER_NOTIF`` return code lets seccomp filters pass a +particular syscall to userspace to be handled. This may be useful for +applications like container managers, which wish to intercept particular +syscalls (``mount()``, ``finit_module()``, etc.) and change their behavior. + +To acquire a notification FD, use the ``SECCOMP_FILTER_FLAG_NEW_LISTENER`` +argument to the ``seccomp()`` syscall: + +.. code-block:: c + + fd = seccomp(SECCOMP_SET_MODE_FILTER, SECCOMP_FILTER_FLAG_NEW_LISTENER, &prog); + +which (on success) will return a listener fd for the filter, which can then be +passed around via ``SCM_RIGHTS`` or similar. Note that filter fds correspond to +a particular filter, and not a particular task. So if this task then forks, +notifications from both tasks will appear on the same filter fd. Reads and +writes to/from a filter fd are also synchronized, so a filter fd can safely +have many readers. + +The interface for a seccomp notification fd consists of two structures: + +.. code-block:: c + + struct seccomp_notif_sizes { + __u16 seccomp_notif; + __u16 seccomp_notif_resp; + __u16 seccomp_data; + }; + + struct seccomp_notif { + __u64 id; + __u32 pid; + __u32 flags; + struct seccomp_data data; + }; + + struct seccomp_notif_resp { + __u64 id; + __s64 val; + __s32 error; + __u32 flags; + }; + +The ``struct seccomp_notif_sizes`` structure can be used to determine the size +of the various structures used in seccomp notifications. The size of ``struct +seccomp_data`` may change in the future, so code should use: + +.. code-block:: c + + struct seccomp_notif_sizes sizes; + seccomp(SECCOMP_GET_NOTIF_SIZES, 0, &sizes); + +to determine the size of the various structures to allocate. See +samples/seccomp/user-trap.c for an example. + +Users can read via ``ioctl(SECCOMP_IOCTL_NOTIF_RECV)`` (or ``poll()``) on a +seccomp notification fd to receive a ``struct seccomp_notif``, which contains +five members: the input length of the structure, a unique-per-filter ``id``, +the ``pid`` of the task which triggered this request (which may be 0 if the +task is in a pid ns not visible from the listener's pid namespace), a ``flags`` +member which for now only has ``SECCOMP_NOTIF_FLAG_SIGNALED``, representing +whether or not the notification is a result of a non-fatal signal, and the +``data`` passed to seccomp. Userspace can then make a decision based on this +information about what to do, and ``ioctl(SECCOMP_IOCTL_NOTIF_SEND)`` a +response, indicating what should be returned to userspace. The ``id`` member of +``struct seccomp_notif_resp`` should be the same ``id`` as in ``struct +seccomp_notif``. + +It is worth noting that ``struct seccomp_data`` contains the values of register +arguments to the syscall, but does not contain pointers to memory. The task's +memory is accessible to suitably privileged traces via ``ptrace()`` or +``/proc/pid/mem``. However, care should be taken to avoid the TOCTOU mentioned +above in this document: all arguments being read from the tracee's memory +should be read into the tracer's memory before any policy decisions are made. +This allows for an atomic decision on syscall arguments. + Sysctls ======= diff --git a/Documentation/vm/index.rst b/Documentation/vm/index.rst index c4ded22197ca..2b3ab3a1ccf3 100644 --- a/Documentation/vm/index.rst +++ b/Documentation/vm/index.rst @@ -2,7 +2,9 @@ Linux Memory Management Documentation ===================================== -This is a collection of documents about Linux memory management (mm) subsystem. +This is a collection of documents about the Linux memory management (mm) +subsystem. If you are looking for advice on simply allocating memory, +see the :ref:`memory-allocation`. User guides for MM features =========================== diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt index 9b93953f69cf..3a91ef5af044 100644 --- a/Documentation/watchdog/watchdog-kernel-api.txt +++ b/Documentation/watchdog/watchdog-kernel-api.txt @@ -128,8 +128,6 @@ struct watchdog_ops { int (*set_pretimeout)(struct watchdog_device *, unsigned int); unsigned int (*get_timeleft)(struct watchdog_device *); int (*restart)(struct watchdog_device *); - void (*ref)(struct watchdog_device *) __deprecated; - void (*unref)(struct watchdog_device *) __deprecated; long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long); }; @@ -218,8 +216,6 @@ they are supported. These optional routines/operations are: if a command is not supported. The parameters that are passed to the ioctl call are: watchdog_device, cmd and arg. -The 'ref' and 'unref' operations are no longer used and deprecated. - The status bits should (preferably) be set with the set_bit and clear_bit alike bit-operations. The status bits that are defined are: * WDOG_ACTIVE: this status bit indicates whether or not a watchdog timer device diff --git a/Documentation/watchdog/watchdog-pm.txt b/Documentation/watchdog/watchdog-pm.txt new file mode 100644 index 000000000000..7a4dd46e0d24 --- /dev/null +++ b/Documentation/watchdog/watchdog-pm.txt @@ -0,0 +1,19 @@ +The Linux WatchDog Timer Power Management Guide +=============================================== +Last reviewed: 17-Dec-2018 + +Wolfram Sang <wsa+renesas@sang-engineering.com> + +Introduction +------------ +This document states rules about watchdog devices and their power management +handling to ensure a uniform behaviour for Linux systems. + + +Ping on resume +-------------- +On resume, a watchdog timer shall be reset to its selected value to give +userspace enough time to resume. [1] [2] + +[1] https://patchwork.kernel.org/patch/10252209/ +[2] https://patchwork.kernel.org/patch/10711625/ diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt index 5e9b826b5f62..f4c2a97bfdbd 100644 --- a/Documentation/x86/boot.txt +++ b/Documentation/x86/boot.txt @@ -58,7 +58,7 @@ Protocol 2.11: (Kernel 3.6) Added a field for offset of EFI handover protocol entry point. Protocol 2.12: (Kernel 3.8) Added the xloadflags field and extension fields - to struct boot_params for loading bzImage and ramdisk + to struct boot_params for loading bzImage and ramdisk above 4G in 64bit. **** MEMORY LAYOUT diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt index ad6d2a80cf05..abc53886655e 100644 --- a/Documentation/x86/x86_64/boot-options.txt +++ b/Documentation/x86/x86_64/boot-options.txt @@ -209,7 +209,7 @@ IOMMU (input/output memory management unit) mapping with memory protection, etc. Kernel boot message: "PCI-DMA: Using Calgary IOMMU" - iommu=[<size>][,noagp][,off][,force][,noforce][,leak[=<nr_of_leak_pages>] + iommu=[<size>][,noagp][,off][,force][,noforce] [,memaper[=<order>]][,merge][,fullflush][,nomerge] [,noaperture][,calgary] @@ -228,9 +228,6 @@ IOMMU (input/output memory management unit) allowed Overwrite iommu off workarounds for specific chipsets. fullflush Flush IOMMU on each allocation (default). nofullflush Don't use IOMMU fullflush. - leak Turn on simple iommu leak tracing (only when - CONFIG_IOMMU_LEAK is on). Default number of leak pages - is 20. memaper[=<order>] Allocate an own aperture over RAM with size 32MB<<order. (default: order=1, i.e. 64MB) merge Do scatter-gather (SG) merging. Implies "force" |