diff options
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 144 |
1 files changed, 117 insertions, 27 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 82b42c958d1c..705fb915cbf7 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -460,6 +460,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted. driver will print ACPI tables for AMD IOMMU during IOMMU initialization. + amd_iommu_intr= [HW,X86-64] + Specifies one of the following AMD IOMMU interrupt + remapping modes: + legacy - Use legacy interrupt remapping mode. + vapic - Use virtual APIC mode, which allows IOMMU + to inject interrupts directly into guest. + This mode requires kvm-amd.avic=1. + (Default when IOMMU HW support is present.) + amijoy.map= [HW,JOY] Amiga joystick support Map of devices attached to JOY0DAT and JOY1DAT Format: <a>,<b> @@ -582,6 +591,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. bootmem_debug [KNL] Enable bootmem allocator debug messages. + bert_disable [ACPI] + Disable BERT OS support on buggy BIOSes. + bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards) bttv.radio= Most important insmod options are available as kernel args too. @@ -687,6 +699,23 @@ bytes respectively. Such letter suffixes can also be entirely omitted. [SPARC64] tick [X86-64] hpet,tsc + clocksource.arm_arch_timer.evtstrm= + [ARM,ARM64] + Format: <bool> + Enable/disable the eventstream feature of the ARM + architected timer so that code using WFE-based polling + loops can be debugged more effectively on production + systems. + + clocksource.arm_arch_timer.fsl-a008585= + [ARM64] + Format: <bool> + Enable/disable the workaround of Freescale/NXP + erratum A-008585. This can be useful for KVM + guests, if the guest device tree doesn't show the + erratum. If unspecified, the workaround is + enabled based on the device tree. + clearcpuid=BITNUM [X86] Disable CPUID feature X for the kernel. See arch/x86/include/asm/cpufeatures.h for the valid bit @@ -920,9 +949,18 @@ bytes respectively. Such letter suffixes can also be entirely omitted. dhash_entries= [KNL] Set number of hash buckets for dentry cache. + disable_1tb_segments [PPC] + Disables the use of 1TB hash page table segments. This + causes the kernel to fall back to 256MB segments which + can be useful when debugging issues that require an SLB + miss to occur. + disable= [IPV6] See Documentation/networking/ipv6.txt. + disable_radix [PPC] + Disable RADIX MMU mode on POWER9 + disable_cpu_apicid= [X86,APIC,SMP] Format: <int> The number of initial APIC ID for the @@ -1025,11 +1063,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. determined by the stdout-path property in device tree's chosen node. - cdns,<addr> - Start an early, polled-mode console on a cadence serial - port at the specified address. The cadence serial port - must already be setup and configured. Options are not - yet supported. + cdns,<addr>[,options] + Start an early, polled-mode console on a Cadence + (xuartps) serial port at the specified address. Only + supported option is baud rate. If baud rate is not + specified, the serial port must already be setup and + configured. uart[8250],io,<addr>[,options] uart[8250],mmio,<addr>[,options] @@ -1185,6 +1224,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Address Range Mirroring feature even if your box doesn't support it. + efivar_ssdt= [EFI; X86] Name of an EFI variable that contains an SSDT + that is to be dynamically loaded by Linux. If there are + multiple variables with the same name but with different + vendor GUIDs, all of them will be loaded. See + Documentation/acpi/ssdt-overlays.txt for details. + + eisa_irq_edge= [PARISC,HW] See header of drivers/parisc/eisa.c. @@ -1337,6 +1383,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Format: <unsigned int> such that (rxsize & ~0x1fffc0) == 0. Default: 1024 + gpio-mockup.gpio_mockup_ranges + [HW] Sets the ranges of gpiochip of for this device. + Format: <start1>,<end1>,<start2>,<end2>... + hardlockup_all_cpu_backtrace= [KNL] Should the hard-lockup detector generate backtraces on all cpus. @@ -1616,6 +1666,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. initrd= [BOOT] Specify the location of the initial ramdisk + init_pkru= [x86] Specify the default memory protection keys rights + register contents for all processes. 0x55555554 by + default (disallow access to all but pkey 0). Can + override in debugfs after boot. + inport.irq= [HW] Inport (ATI XL and Microsoft) busmouse driver Format: <irq> @@ -1661,7 +1716,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. intel_idle.max_cstate= [KNL,HW,ACPI,X86] 0 disables intel_idle and fall back on acpi_idle. - 1 to 6 specify maximum depth of C-state. + 1 to 9 specify maximum depth of C-state. intel_pstate= [X86] disable @@ -1803,12 +1858,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. js= [HW,JOY] Analog joystick See Documentation/input/joystick.txt. - kaslr/nokaslr [X86] - Enable/disable kernel and module base offset ASLR - (Address Space Layout Randomization) if built into - the kernel. When CONFIG_HIBERNATION is selected, - kASLR is disabled by default. When kASLR is enabled, - hibernation will be disabled. + nokaslr [KNL] + When CONFIG_RANDOMIZE_BASE is set, this disables + kernel and module base offset ASLR (Address Space + Layout Randomization). keepinitrd [HW,ARM] @@ -2136,10 +2189,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. than or equal to this physical address is ignored. maxcpus= [SMP] Maximum number of processors that an SMP kernel - should make use of. maxcpus=n : n >= 0 limits the - kernel to using 'n' processors. n=0 is a special case, - it is equivalent to "nosmp", which also disables - the IO APIC. + will bring up during bootup. maxcpus=n : n >= 0 limits + the kernel to bring up 'n' processors. Surely after + bootup you can bring up the other plugged cpu by executing + "echo 1 > /sys/devices/system/cpu/cpuX/online". So maxcpus + only takes effect during system bootup. + While n=0 is a special case, it is equivalent to "nosmp", + which also disables the IO APIC. max_loop= [LOOP] The number of loop block devices that get (loop.max_loop) unconditionally pre-created at init time. The default @@ -2295,6 +2351,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Note that if CONFIG_MODULE_SIG_FORCE is set, that is always true, so this option does nothing. + module_blacklist= [KNL] Do not load a comma-separated list of + modules. Useful for debugging problem modules. + mousedev.tap_time= [MOUSE] Maximum time between finger touching and leaving touchpad surface for touch to be considered @@ -2543,8 +2602,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted. nodelayacct [KNL] Disable per-task delay accounting - nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects. - nodsp [SH] Disable hardware DSP at boot time. noefi Disable EFI runtime services support. @@ -2745,9 +2802,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. nr_cpus= [SMP] Maximum number of processors that an SMP kernel could support. nr_cpus=n : n >= 1 limits the kernel to - supporting 'n' processors. Later in runtime you can not - use hotplug cpu feature to put more cpu back to online. - just like you compile the kernel NR_CPUS=n + support 'n' processors. It could be larger than the + number of already plugged CPU during bootup, later in + runtime you can physically add extra cpu until it reaches + n. So during boot up some boot time memory for per-cpu + variables need be pre-allocated for later physical cpu + hot plugging. nr_uarts= [SERIAL] maximum number of UARTs to be registered. @@ -2788,8 +2848,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted. timer: [X86] Force use of architectural NMI timer mode (see also oprofile.timer for generic hr timer mode) - [s390] Force legacy basic mode sampling - (report cpu_type "timer") oops=panic Always panic on oopses. Default is to just kill the process, but there is a small probability of @@ -2998,12 +3056,18 @@ bytes respectively. Such letter suffixes can also be entirely omitted. resource_alignment= Format: [<order of align>@][<domain>:]<bus>:<slot>.<func>[; ...] + [<order of align>@]pci:<vendor>:<device>\ + [:<subvendor>:<subdevice>][; ...] Specifies alignment and device to reassign aligned memory resources. If <order of align> is not specified, PAGE_SIZE is used as alignment. PCI-PCI bridge can be specified, if resource windows need to be expanded. + To specify the alignment for several + instances of a device, the PCI vendor, + device, subvendor, and subdevice may be + specified, e.g., 4096@pci:8086:9c22:103c:198f ecrc= Enable/disable PCIe ECRC (transaction layer end-to-end CRC checking). bios: Use BIOS/firmware settings. This is the @@ -3016,6 +3080,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. hpmemsize=nn[KMG] The fixed amount of bus space which is reserved for hotplug bridge's memory window. Default size is 2 megabytes. + hpbussize=nn The minimum amount of additional bus numbers + reserved for buses below a hotplug bridge. + Default is 1. realloc= Enable/disable reallocating PCI bridge resources if allocations done by BIOS are too small to accommodate resources required by all child @@ -3047,6 +3114,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. compat Treat PCIe ports as PCI-to-PCI bridges, disable the PCIe ports driver. + pcie_port_pm= [PCIE] PCIe port power management handling: + off Disable power management of all PCIe ports + force Forcibly enable power management of all PCIe ports + pcie_pme= [PCIE,PM] Native PCIe PME signaling options: nomsi Do not use MSI for native PCIe PME signaling (this makes all PCIe root ports use INTx for all services). @@ -3150,6 +3221,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Format: <bool> (1/Y/y=enable, 0/N/n=disable) default: disabled + printk.devkmsg={on,off,ratelimit} + Control writing to /dev/kmsg. + on - unlimited logging to /dev/kmsg from userspace + off - logging to /dev/kmsg disabled + ratelimit - ratelimit the logging + Default: ratelimit + printk.time= Show timing data prefixed to each printk message line Format: <bool> (1/Y/y=enable, 0/N/n=disable) @@ -3547,7 +3625,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. relax_domain_level= [KNL, SMP] Set scheduler's default relax_domain_level. - See Documentation/cgroups/cpusets.txt. + See Documentation/cgroup-v1/cpusets.txt. relative_sleep_states= [SUSPEND] Use sleep state labeling where the deepest @@ -3594,6 +3672,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. present during boot. nocompress Don't compress/decompress hibernation images. no Disable hibernation and resume. + protect_image Turn on image protection during restoration + (that will set all pages holding image data + during restoration read-only). retain_initrd [RAM] Keep initrd memory after extraction @@ -3832,6 +3913,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. using these two parameters to set the minimum and maximum port values. + sunrpc.svc_rpc_per_connection_limit= + [NFS,SUNRPC] + Limit the number of requests that the server will + process in parallel from a single connection. + The default value is 0 (no limit). + sunrpc.pool_mode= [NFS] Control how the NFS server code allocates CPUs to @@ -3867,7 +3954,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. swapaccount=[0|1] [KNL] Enable accounting of swap in memory resource controller if no parameter or 1 is given or disable - it if 0 is given (See Documentation/cgroups/memory.txt) + it if 0 is given (See Documentation/cgroup-v1/memory.txt) swiotlb= [ARM,IA-64,PPC,MIPS,X86] Format: { <int> | force } @@ -3992,8 +4079,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. trace_event=[event-list] [FTRACE] Set and start specified trace events in order - to facilitate early boot debugging. - See also Documentation/trace/events.txt + to facilitate early boot debugging. The event-list is a + comma separated list of trace events to enable. See + also Documentation/trace/events.txt trace_options=[option-list] [FTRACE] Enable or disable tracer options at boot. @@ -4182,6 +4270,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. u = IGNORE_UAS (don't bind to the uas driver); w = NO_WP_DETECT (don't test whether the medium is write-protected). + y = ALWAYS_SYNC (issue a SYNCHRONIZE_CACHE + even if the device claims no cache) Example: quirks=0419:aaf5:rl,0421:0433:rc user_debug= [KNL,ARM] |