kernel/linux.git/include/linux/mm.h, branch linux-5.9.y

mm: always have io_remap_pfn_range() set pgprot_decrypted()

2020-11-10T11:39:00+00:00

commit f8f6ae5d077a9bdaf5cbf2ac960a5d1a04b47482 upstream. The purpose of io_remap_pfn_range() is to map IO memory, such as a memory mapped IO exposed through a PCI BAR. IO devices do not understand encryption, so this memory must always be decrypted. Automatically call pgprot_decrypted() as part of the generic implementation. This fixes a bug where enabling AMD SME causes subsystems, such as RDMA, using io_remap_pfn_range() to expose BAR pages to user space to fail. The CPU will encrypt access to those BAR pages instead of passing unencrypted IO directly to the device. Places not mapping IO should use remap_pfn_range(). Fixes: aca20d546214 ("x86/mm: Add support to make use of Secure Memory Encryption") Signed-off-by: Jason Gunthorpe Signed-off-by: Andrew Morton Cc: Arnd Bergmann Cc: Tom Lendacky Cc: Thomas Gleixner Cc: Andrey Ryabinin Cc: Borislav Petkov Cc: Brijesh Singh Cc: Jonathan Corbet Cc: Dmitry Vyukov Cc: "Dave Young" Cc: Alexander Potapenko Cc: Konrad Rzeszutek Wilk Cc: Andy Lutomirski Cc: Larry Woodman Cc: Matt Fleming Cc: Ingo Molnar Cc: "Michael S. Tsirkin" Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Rik van Riel Cc: Toshimitsu Kani Cc: Link: https://lkml.kernel.org/r/0-v1-025d64bdf6c4+e-amd_sme_fix_jgg@nvidia.com Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/fork: Pass new vma pointer into copy_page_range()

2020-09-27T18:21:35+00:00

This prepares for the future work to trigger early cow on pinned pages during fork(). No functional change intended. Signed-off-by: Peter Xu Signed-off-by: Linus Torvalds

mm: replace memmap_context by meminit_context

2020-09-26T17:33:57+00:00

Patch series "mm: fix memory to node bad links in sysfs", v3. Sometimes, firmware may expose interleaved memory layout like this: Early memory node ranges node 1: [mem 0x0000000000000000-0x000000011fffffff] node 2: [mem 0x0000000120000000-0x000000014fffffff] node 1: [mem 0x0000000150000000-0x00000001ffffffff] node 0: [mem 0x0000000200000000-0x000000048fffffff] node 2: [mem 0x0000000490000000-0x00000007ffffffff] In that case, we can see memory blocks assigned to multiple nodes in sysfs: $ ls -l /sys/devices/system/memory/memory21 total 0 lrwxrwxrwx 1 root root 0 Aug 24 05:27 node1 -> ../../node/node1 lrwxrwxrwx 1 root root 0 Aug 24 05:27 node2 -> ../../node/node2 -rw-r--r-- 1 root root 65536 Aug 24 05:27 online -r--r--r-- 1 root root 65536 Aug 24 05:27 phys_device -r--r--r-- 1 root root 65536 Aug 24 05:27 phys_index drwxr-xr-x 2 root root 0 Aug 24 05:27 power -r--r--r-- 1 root root 65536 Aug 24 05:27 removable -rw-r--r-- 1 root root 65536 Aug 24 05:27 state lrwxrwxrwx 1 root root 0 Aug 24 05:25 subsystem -> ../../../../bus/memory -rw-r--r-- 1 root root 65536 Aug 24 05:25 uevent -r--r--r-- 1 root root 65536 Aug 24 05:27 valid_zones The same applies in the node's directory with a memory21 link in both the node1 and node2's directory. This is wrong but doesn't prevent the system to run. However when later, one of these memory blocks is hot-unplugged and then hot-plugged, the system is detecting an inconsistency in the sysfs layout and a BUG_ON() is raised: kernel BUG at /Users/laurent/src/linux-ppc/mm/memory_hotplug.c:1084! LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: rpadlpar_io rpaphp pseries_rng rng_core vmx_crypto gf128mul binfmt_misc ip_tables x_tables xfs libcrc32c crc32c_vpmsum autofs4 CPU: 8 PID: 10256 Comm: drmgr Not tainted 5.9.0-rc1+ #25 Call Trace: add_memory_resource+0x23c/0x340 (unreliable) __add_memory+0x5c/0xf0 dlpar_add_lmb+0x1b4/0x500 dlpar_memory+0x1f8/0xb80 handle_dlpar_errorlog+0xc0/0x190 dlpar_store+0x198/0x4a0 kobj_attr_store+0x30/0x50 sysfs_kf_write+0x64/0x90 kernfs_fop_write+0x1b0/0x290 vfs_write+0xe8/0x290 ksys_write+0xdc/0x130 system_call_exception+0x160/0x270 system_call_common+0xf0/0x27c This has been seen on PowerPC LPAR. The root cause of this issue is that when node's memory is registered, the range used can overlap another node's range, thus the memory block is registered to multiple nodes in sysfs. There are two issues here: (a) The sysfs memory and node's layouts are broken due to these multiple links (b) The link errors in link_mem_sections() should not lead to a system panic. To address (a) register_mem_sect_under_node should not rely on the system state to detect whether the link operation is triggered by a hot plug operation or not. This is addressed by the patches 1 and 2 of this series. Issue (b) will be addressed separately. This patch (of 2): The memmap_context enum is used to detect whether a memory operation is due to a hot-add operation or happening at boot time. Make it general to the hotplug operation and rename it as meminit_context. There is no functional change introduced by this patch Suggested-by: David Hildenbrand Signed-off-by: Laurent Dufour Signed-off-by: Andrew Morton Reviewed-by: David Hildenbrand Reviewed-by: Oscar Salvador Acked-by: Michal Hocko Cc: Greg Kroah-Hartman Cc: "Rafael J . Wysocki" Cc: Nathan Lynch Cc: Scott Cheloha Cc: Tony Luck Cc: Fenghua Yu Cc: Link: https://lkml.kernel.org/r/20200915094143.79181-1-ldufour@linux.ibm.com Link: https://lkml.kernel.org/r/20200915132624.9723-1-ldufour@linux.ibm.com Signed-off-by: Linus Torvalds

mm: allow a controlled amount of unfairness in the page lock

2020-09-17T17:26:41+00:00

Commit 2a9127fcf229 ("mm: rewrite wait_on_page_bit_common() logic") made the page locking entirely fair, in that if a waiter came in while the lock was held, the lock would be transferred to the lockers strictly in order. That was intended to finally get rid of the long-reported watchdog failures that involved the page lock under extreme load, where a process could end up waiting essentially forever, as other page lockers stole the lock from under it. It also improved some benchmarks, but it ended up causing huge performance regressions on others, simply because fair lock behavior doesn't end up giving out the lock as aggressively, causing better worst-case latency, but potentially much worse average latencies and throughput. Instead of reverting that change entirely, this introduces a controlled amount of unfairness, with a sysctl knob to tune it if somebody needs to. But the default value should hopefully be good for any normal load, allowing a few rounds of lock stealing, but enforcing the strict ordering before the lock has been stolen too many times. There is also a hint from Matthieu Baerts that the fair page coloring may end up exposing an ABBA deadlock that is hidden by the usual optimistic lock stealing, and while the unfairness doesn't fix the fundamental issue (and I'm still looking at that), it avoids it in practice. The amount of unfairness can be modified by writing a new value to the 'sysctl_page_lock_unfairness' variable (default value of 5, exposed through /proc/sys/vm/page_lock_unfairness), but that is hopefully something we'd use mainly for debugging rather than being necessary for any deep system tuning. This whole issue has exposed just how critical the page lock can be, and how contended it gets under certain locks. And the main contention doesn't really seem to be anything related to IO (which was the origin of this lock), but for things like just verifying that the page file mapping is stable while faulting in the page into a page table. Link: https://lore.kernel.org/linux-fsdevel/ed8442fd-6f54-dd84-cd4a-941e8b7ee603@MichaelLarabel.com/ Link: https://www.phoronix.com/scan.php?page=article&item=linux-50-59&num=1 Link: https://lore.kernel.org/linux-fsdevel/c560a38d-8313-51fb-b1ec-e904bd8836bc@tessares.net/ Reported-and-tested-by: Michael Larabel Tested-by: Matthieu Baerts Cc: Dave Chinner Cc: Matthew Wilcox Cc: Chris Mason Cc: Jan Kara Cc: Amir Goldstein Signed-off-by: Linus Torvalds

Merge tag 'powerpc-5.9-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2020-08-30T17:56:12+00:00

Pull powerpc fixes from Michael Ellerman: - Revert our removal of PROT_SAO, at least one user expressed an interest in using it on Power9. Instead don't allow it to be used in guests unless enabled explicitly at compile time. - A fix for a crash introduced by a recent change to FP handling. - Revert a change to our idle code that left Power10 with no idle support. - One minor fix for the new scv system call path to set PPR. - Fix a crash in our "generic" PMU if branch stack events were enabled. - A fix for the IMC PMU, to correctly identify host kernel samples. - The ADB_PMU powermac code was found to be incompatible with VMAP_STACK, so make them incompatible in Kconfig until the code can be fixed. - A build fix in drivers/video/fbdev/controlfb.c, and a documentation fix. Thanks to Alexey Kardashevskiy, Athira Rajeev, Christophe Leroy, Giuseppe Sacco, Madhavan Srinivasan, Milton Miller, Nicholas Piggin, Pratik Rajesh Sampat, Randy Dunlap, Shawn Anastasio, Vaidyanathan Srinivasan. * tag 'powerpc-5.9-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/32s: Disable VMAP stack which CONFIG_ADB_PMU Revert "powerpc/powernv/idle: Replace CPU feature check with PVR check" powerpc/perf: Fix reading of MSR[HV/PR] bits in trace-imc powerpc/perf: Fix crashes with generic_compat_pmu & BHRB powerpc/64s: Fix crash in load_fp_state() due to fpexc_mode powerpc/64s: scv entry should set PPR Documentation/powerpc: fix malformed table in syscall64-abi video: fbdev: controlfb: Fix build for COMPILE_TEST=y && PPC_PMAC=n selftests/powerpc: Update PROT_SAO test to skip ISA 3.1 powerpc/64s: Disallow PROT_SAO in LPARs by default Revert "powerpc/64s: Remove PROT_SAO support"

Revert "powerpc/64s: Remove PROT_SAO support"

2020-08-24T04:12:53+00:00

This reverts commit 5c9fa16e8abd342ce04dc830c1ebb2a03abf6c05. Since PROT_SAO can still be useful for certain classes of software, reintroduce it. Concerns about guest migration for LPARs using SAO will be addressed next. Signed-off-by: Shawn Anastasio Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200821185558.35561-2-shawn@anastas.io

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

mm: annotate a data race in page_zonenum()

2020-08-15T02:56:57+00:00

BUG: KCSAN: data-race in page_cpupid_xchg_last / put_page write (marked) to 0xfffffc0d48ec1a00 of 8 bytes by task 91442 on cpu 3: page_cpupid_xchg_last+0x51/0x80 page_cpupid_xchg_last at mm/mmzone.c:109 (discriminator 11) wp_page_reuse+0x3e/0xc0 wp_page_reuse at mm/memory.c:2453 do_wp_page+0x472/0x7b0 do_wp_page at mm/memory.c:2798 __handle_mm_fault+0xcb0/0xd00 handle_pte_fault at mm/memory.c:4049 (inlined by) __handle_mm_fault at mm/memory.c:4163 handle_mm_fault+0xfc/0x2f0 handle_mm_fault at mm/memory.c:4200 do_page_fault+0x263/0x6f9 do_user_addr_fault at arch/x86/mm/fault.c:1465 (inlined by) do_page_fault at arch/x86/mm/fault.c:1539 page_fault+0x34/0x40 read to 0xfffffc0d48ec1a00 of 8 bytes by task 94817 on cpu 69: put_page+0x15a/0x1f0 page_zonenum at include/linux/mm.h:923 (inlined by) is_zone_device_page at include/linux/mm.h:929 (inlined by) page_is_devmap_managed at include/linux/mm.h:948 (inlined by) put_page at include/linux/mm.h:1023 wp_page_copy+0x571/0x930 wp_page_copy at mm/memory.c:2615 do_wp_page+0x107/0x7b0 __handle_mm_fault+0xcb0/0xd00 handle_mm_fault+0xfc/0x2f0 do_page_fault+0x263/0x6f9 page_fault+0x34/0x40 Reported by Kernel Concurrency Sanitizer on: CPU: 69 PID: 94817 Comm: systemd-udevd Tainted: G W O L 5.5.0-next-20200204+ #6 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 A page never changes its zone number. The zone number happens to be stored in the same word as other bits which are modified, but the zone number bits will never be modified by any other write, so it can accept a reload of the zone bits after an intervening write and it don't need to use READ_ONCE(). Thus, annotate this data race using ASSERT_EXCLUSIVE_BITS() to also assert that there are no concurrent writes to it. Suggested-by: Marco Elver Signed-off-by: Qian Cai Signed-off-by: Andrew Morton Cc: Paul E. McKenney Cc: David Hildenbrand Cc: Jan Kara Cc: John Hubbard Cc: Ira Weiny Cc: Dan Williams Link: http://lkml.kernel.org/r/1581619089-14472-1-git-send-email-cai@lca.pw Signed-off-by: Linus Torvalds

mm: introduce offset_in_thp

2020-08-15T02:56:56+00:00

Mirroring offset_in_page(), this gives you the offset within this particular page, no matter what size page it is. It optimises down to offset_in_page() if CONFIG_TRANSPARENT_HUGEPAGE is not set. Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton Reviewed-by: David Hildenbrand Reviewed-by: William Kucharski Reviewed-by: Zi Yan Cc: Mike Kravetz Cc: "Kirill A. Shutemov" Link: http://lkml.kernel.org/r/20200629151959.15779-8-willy@infradead.org Signed-off-by: Linus Torvalds

mm: move page-flags include to top of file

2020-08-15T02:56:56+00:00

Give up on the notion that we can remove page-flags.h from mm.h. There are currently 14 inline functions which use a PageFoo function. Also, two of the files directly included by mm.h include page-flags.h themselves, and there are probably more indirect inclusions. So just include it at the top like any other header file. Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton Reviewed-by: William Kucharski Reviewed-by: Zi Yan Cc: David Hildenbrand Cc: Mike Kravetz Cc: "Kirill A. Shutemov" Link: http://lkml.kernel.org/r/20200629151959.15779-3-willy@infradead.org Signed-off-by: Linus Torvalds