kernel/linux.git/tools/include/uapi/asm-generic, branch v6.1.168

asm-generic: Unify uapi bitsperlong.h for arm64, riscv and loongarch

2025-12-06T21:12:34+00:00

[ Upstream commit 8386f58f8deda81110283798a387fb53ec21957c ] Now we specify the minimal version of GCC as 5.1 and Clang/LLVM as 11.0.0 in Documentation/process/changes.rst, __CHAR_BIT__ and __SIZEOF_LONG__ are usable, it is probably fine to unify the definition of __BITS_PER_LONG as (__CHAR_BIT__ * __SIZEOF_LONG__) in asm-generic uapi bitsperlong.h. In order to keep safe and avoid regression, only unify uapi bitsperlong.h for some archs such as arm64, riscv and loongarch which are using newer toolchains that have the definitions of __CHAR_BIT__ and __SIZEOF_LONG__. Suggested-by: Xi Ruoyao Link: https://lore.kernel.org/all/d3e255e4746de44c9903c4433616d44ffcf18d1b.camel@xry111.site/ Suggested-by: Arnd Bergmann Link: https://lore.kernel.org/linux-arch/a3a4f48a-07d4-4ed9-bc53-5d383428bdd2@app.fastmail.com/ Signed-off-by: Tiezhu Yang Signed-off-by: Arnd Bergmann Signed-off-by: Sasha Levin

open: return EINVAL for O_DIRECTORY | O_CREAT

2023-05-24T16:32:34+00:00

[ Upstream commit 43b450632676fb60e9faeddff285d9fac94a4f58 ] After a couple of years and multiple LTS releases we received a report that the behavior of O_DIRECTORY | O_CREAT changed starting with v5.7. On kernels prior to v5.7 combinations of O_DIRECTORY, O_CREAT, O_EXCL had the following semantics: (1) open("/tmp/d", O_DIRECTORY | O_CREAT) * d doesn't exist: create regular file * d exists and is a regular file: ENOTDIR * d exists and is a directory: EISDIR (2) open("/tmp/d", O_DIRECTORY | O_CREAT | O_EXCL) * d doesn't exist: create regular file * d exists and is a regular file: EEXIST * d exists and is a directory: EEXIST (3) open("/tmp/d", O_DIRECTORY | O_EXCL) * d doesn't exist: ENOENT * d exists and is a regular file: ENOTDIR * d exists and is a directory: open directory On kernels since to v5.7 combinations of O_DIRECTORY, O_CREAT, O_EXCL have the following semantics: (1) open("/tmp/d", O_DIRECTORY | O_CREAT) * d doesn't exist: ENOTDIR (create regular file) * d exists and is a regular file: ENOTDIR * d exists and is a directory: EISDIR (2) open("/tmp/d", O_DIRECTORY | O_CREAT | O_EXCL) * d doesn't exist: ENOTDIR (create regular file) * d exists and is a regular file: EEXIST * d exists and is a directory: EEXIST (3) open("/tmp/d", O_DIRECTORY | O_EXCL) * d doesn't exist: ENOENT * d exists and is a regular file: ENOTDIR * d exists and is a directory: open directory This is a fairly substantial semantic change that userspace didn't notice until Pedro took the time to deliberately figure out corner cases. Since no one noticed this breakage we can somewhat safely assume that O_DIRECTORY | O_CREAT combinations are likely unused. The v5.7 breakage is especially weird because while ENOTDIR is returned indicating failure a regular file is actually created. This doesn't make a lot of sense. Time was spent finding potential users of this combination. Searching on codesearch.debian.net showed that codebases often express semantical expectations about O_DIRECTORY | O_CREAT which are completely contrary to what our code has done and currently does. The expectation often is that this particular combination would create and open a directory. This suggests users who tried to use that combination would stumble upon the counterintuitive behavior no matter if pre-v5.7 or post v5.7 and quickly realize neither semantics give them what they want. For some examples see the code examples in [1] to [3] and the discussion in [4]. There are various ways to address this issue. The lazy/simple option would be to restore the pre-v5.7 behavior and to just live with that bug forever. But since there's a real chance that the O_DIRECTORY | O_CREAT quirk isn't relied upon we should try to get away with murder(ing bad semantics) first. If we need to Frankenstein pre-v5.7 behavior later so be it. So let's simply return EINVAL categorically for O_DIRECTORY | O_CREAT combinations. In addition to cleaning up the old bug this also opens up the possiblity to make that flag combination do something more intuitive in the future. Starting with this commit the following semantics apply: (1) open("/tmp/d", O_DIRECTORY | O_CREAT) * d doesn't exist: EINVAL * d exists and is a regular file: EINVAL * d exists and is a directory: EINVAL (2) open("/tmp/d", O_DIRECTORY | O_CREAT | O_EXCL) * d doesn't exist: EINVAL * d exists and is a regular file: EINVAL * d exists and is a directory: EINVAL (3) open("/tmp/d", O_DIRECTORY | O_EXCL) * d doesn't exist: ENOENT * d exists and is a regular file: ENOTDIR * d exists and is a directory: open directory One additional note, O_TMPFILE is implemented as: #define __O_TMPFILE 020000000 #define O_TMPFILE (__O_TMPFILE | O_DIRECTORY) #define O_TMPFILE_MASK (__O_TMPFILE | O_DIRECTORY | O_CREAT) For older kernels it was important to return an explicit error when O_TMPFILE wasn't supported. So O_TMPFILE requires that O_DIRECTORY is raised alongside __O_TMPFILE. It also enforced that O_CREAT wasn't specified. Since O_DIRECTORY | O_CREAT could be used to create a regular allowing that combination together with __O_TMPFILE would've meant that false positives were possible, i.e., that a regular file was created instead of a O_TMPFILE. This could've been used to trick userspace into thinking it operated on a O_TMPFILE when it wasn't. Now that we block O_DIRECTORY | O_CREAT completely the check for O_CREAT in the __O_TMPFILE branch via if ((flags & O_TMPFILE_MASK) != O_TMPFILE) can be dropped. Instead we can simply check verify that O_DIRECTORY is raised via if (!(flags & O_DIRECTORY)) and explain this in two comments. As Aleksa pointed out O_PATH is unaffected by this change since it always returned EINVAL if O_CREAT was specified - with or without O_DIRECTORY. Link: https://lore.kernel.org/lkml/20230320071442.172228-1-pedro.falcato@gmail.com Link: https://sources.debian.org/src/flatpak/1.14.4-1/subprojects/libglnx/glnx-dirfd.c/?hl=324#L324 [1] Link: https://sources.debian.org/src/flatpak-builder/1.2.3-1/subprojects/libglnx/glnx-shutil.c/?hl=251#L251 [2] Link: https://sources.debian.org/src/ostree/2022.7-2/libglnx/glnx-dirfd.c/?hl=324#L324 [3] Link: https://www.openwall.com/lists/oss-security/2014/11/26/14 [4] Reported-by: Pedro Falcato Cc: Aleksa Sarai Signed-off-by: Linus Torvalds Signed-off-by: Christian Brauner Signed-off-by: Sasha Levin

mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse

2022-09-12T03:25:46+00:00

This idea was introduced by David Rientjes[1]. Introduce a new madvise mode, MADV_COLLAPSE, that allows users to request a synchronous collapse of memory at their own expense. The benefits of this approach are: * CPU is charged to the process that wants to spend the cycles for the THP * Avoid unpredictable timing of khugepaged collapse Semantics This call is independent of the system-wide THP sysfs settings, but will fail for memory marked VM_NOHUGEPAGE. If the ranges provided span multiple VMAs, the semantics of the collapse over each VMA is independent from the others. This implies a hugepage cannot cross a VMA boundary. If collapse of a given hugepage-aligned/sized region fails, the operation may continue to attempt collapsing the remainder of memory specified. The memory ranges provided must be page-aligned, but are not required to be hugepage-aligned. If the memory ranges are not hugepage-aligned, the start/end of the range will be clamped to the first/last hugepage-aligned address covered by said range. The memory ranges must span at least one hugepage-sized region. All non-resident pages covered by the range will first be swapped/faulted-in, before being internally copied onto a freshly allocated hugepage. Unmapped pages will have their data directly initialized to 0 in the new hugepage. However, for every eligible hugepage aligned/sized region to-be collapsed, at least one page must currently be backed by memory (a PMD covering the address range must already exist). Allocation for the new hugepage may enter direct reclaim and/or compaction, regardless of VMA flags. When the system has multiple NUMA nodes, the hugepage will be allocated from the node providing the most native pages. This operation operates on the current state of the specified process and makes no persistent changes or guarantees on how pages will be mapped, constructed, or faulted in the future Return Value If all hugepage-sized/aligned regions covered by the provided range were either successfully collapsed, or were already PMD-mapped THPs, this operation will be deemed successful. On success, process_madvise(2) returns the number of bytes advised, and madvise(2) returns 0. Else, -1 is returned and errno is set to indicate the error for the most-recently attempted hugepage collapse. Note that many failures might have occurred, since the operation may continue to collapse in the event a single hugepage-sized/aligned region fails. ENOMEM Memory allocation failed or VMA not found EBUSY Memcg charging failed EAGAIN Required resource temporarily unavailable. Try again might succeed. EINVAL Other error: No PMD found, subpage doesn't have Present bit set, "Special" page no backed by struct page, VMA incorrectly sized, address not page-aligned, ... Most notable here is ENOMEM and EBUSY (new to madvise) which are intended to provide the caller with actionable feedback so they may take an appropriate fallback measure. Use Cases An immediate user of this new functionality are malloc() implementations that manage memory in hugepage-sized chunks, but sometimes subrelease memory back to the system in native-sized chunks via MADV_DONTNEED; zapping the pmd. Later, when the memory is hot, the implementation could madvise(MADV_COLLAPSE) to re-back the memory by THPs to regain hugepage coverage and dTLB performance. TCMalloc is such an implementation that could benefit from this[2]. Only privately-mapped anon memory is supported for now, but additional support for file, shmem, and HugeTLB high-granularity mappings[2] is expected. File and tmpfs/shmem support would permit: * Backing executable text by THPs. Current support provided by CONFIG_READ_ONLY_THP_FOR_FS may take a long time on a large system which might impair services from serving at their full rated load after (re)starting. Tricks like mremap(2)'ing text onto anonymous memory to immediately realize iTLB performance prevents page sharing and demand paging, both of which increase steady state memory footprint. With MADV_COLLAPSE, we get the best of both worlds: Peak upfront performance and lower RAM footprints. * Backing guest memory by hugapages after the memory contents have been migrated in native-page-sized chunks to a new host, in a userfaultfd-based live-migration stack. [1] https://lore.kernel.org/linux-mm/d098c392-273a-36a4-1a29-59731cdf5d3d@google.com/ [2] https://github.com/google/tcmalloc/tree/master/tcmalloc [jrdr.linux@gmail.com: avoid possible memory leak in failure path] Link: https://lkml.kernel.org/r/20220713024109.62810-1-jrdr.linux@gmail.com [zokeefe@google.com add missing kfree() to madvise_collapse()] Link: https://lore.kernel.org/linux-mm/20220713024109.62810-1-jrdr.linux@gmail.com/ Link: https://lkml.kernel.org/r/20220713161851.1879439-1-zokeefe@google.com [zokeefe@google.com: delay computation of hpage boundaries until use]] Link: https://lkml.kernel.org/r/20220720140603.1958773-4-zokeefe@google.com Link: https://lkml.kernel.org/r/20220706235936.2197195-10-zokeefe@google.com Signed-off-by: Zach O'Keefe Signed-off-by: "Souptick Joarder (HPE)" Suggested-by: David Rientjes Cc: Alex Shi Cc: Andrea Arcangeli Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Chris Kennelly Cc: Chris Zankel Cc: David Hildenbrand Cc: Helge Deller Cc: Hugh Dickins Cc: Ivan Kokshaysky Cc: James Bottomley Cc: Jens Axboe Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Miaohe Lin Cc: Michal Hocko Cc: Minchan Kim Cc: Pasha Tatashin Cc: Pavel Begunkov Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Thomas Bogendoerfer Cc: Vlastimil Babka Cc: Yang Shi Cc: Zi Yan Cc: Dan Carpenter Signed-off-by: Andrew Morton

Merge tag 'asm-generic-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2022-08-05T17:07:23+00:00

Pull asm-generic updates from Arnd Bergmann: "There are three independent sets of changes: - Sai Prakash Ranjan adds tracing support to the asm-generic version of the MMIO accessors, which is intended to help understand problems with device drivers and has been part of Qualcomm's vendor kernels for many years - A patch from Sebastian Siewior to rework the handling of IRQ stacks in softirqs across architectures, which is needed for enabling PREEMPT_RT - The last patch to remove the CONFIG_VIRT_TO_BUS option and some of the code behind that, after the last users of this old interface made it in through the netdev, scsi, media and staging trees" * tag 'asm-generic-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: uapi: asm-generic: fcntl: Fix typo 'the the' in comment arch/*/: remove CONFIG_VIRT_TO_BUS soc: qcom: geni: Disable MMIO tracing for GENI SE serial: qcom_geni_serial: Disable MMIO tracing for geni serial asm-generic/io: Add logging support for MMIO accessors KVM: arm64: Add a flag to disable MMIO trace for nVHE KVM lib: Add register read/write tracing support drm/meson: Fix overflow implicit truncation warnings irqchip/tegra: Fix overflow implicit truncation warnings coresight: etm4x: Use asm-generic IO memory barriers arm64: io: Use asm-generic high level MMIO accessors arch/*: Disable softirq stacks on PREEMPT_RT.

uapi: asm-generic: fcntl: Fix typo 'the the' in comment

2022-07-22T12:54:22+00:00

Replace 'the the' with 'the' in the comment. Signed-off-by: Slark Xiao Signed-off-by: Arnd Bergmann

tools: Fixed MIPS builds due to struct flock re-definition

2022-07-20T10:55:33+00:00

Building perf for MIPS failed after 9f79b8b72339 ("uapi: simplify __ARCH_FLOCK{,64}_PAD a little") with the following error: CC /home/fainelli/work/buildroot/output/bmips/build/linux-custom/tools/perf/trace/beauty/fcntl.o In file included from ../../../../host/mipsel-buildroot-linux-gnu/sysroot/usr/include/asm/fcntl.h:77, from ../include/uapi/linux/fcntl.h:5, from trace/beauty/fcntl.c:10: ../include/uapi/asm-generic/fcntl.h:188:8: error: redefinition of 'struct flock' struct flock { ^~~~~ In file included from ../include/uapi/linux/fcntl.h:5, from trace/beauty/fcntl.c:10: ../../../../host/mipsel-buildroot-linux-gnu/sysroot/usr/include/asm/fcntl.h:63:8: note: originally defined here struct flock { ^~~~~ This is due to the local copy under tools/include/uapi/asm-generic/fcntl.h including the toolchain's kernel headers which already define 'struct flock' and define HAVE_ARCH_STRUCT_FLOCK to future inclusions make a decision as to whether re-defining 'struct flock' is appropriate or not. Make sure what do not re-define 'struct flock' when HAVE_ARCH_STRUCT_FLOCK is already defined. Fixes: 9f79b8b72339 ("uapi: simplify __ARCH_FLOCK{,64}_PAD a little") Signed-off-by: Florian Fainelli Reviewed-by: Christoph Hellwig [arnd: sync with include/uapi/asm-generic/fcntl.h as well] Signed-off-by: Arnd Bergmann

Merge tag 'riscv-for-linus-5.19-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2022-05-31T21:10:54+00:00

Pull RISC-V updates from Palmer Dabbelt: - Support for the Svpbmt extension, which allows memory attributes to be encoded in pages - Support for the Allwinner D1's implementation of page-based memory attributes - Support for running rv32 binaries on rv64 systems, via the compat subsystem - Support for kexec_file() - Support for the new generic ticket-based spinlocks, which allows us to also move to qrwlock. These should have already gone in through the asm-geneic tree as well - A handful of cleanups and fixes, include some larger ones around atomics and XIP * tag 'riscv-for-linus-5.19-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (51 commits) RISC-V: Prepare dropping week attribute from arch_kexec_apply_relocations[_add] riscv: compat: Using seperated vdso_maps for compat_vdso_info RISC-V: Fix the XIP build RISC-V: Split out the XIP fixups into their own file RISC-V: ignore xipImage RISC-V: Avoid empty create_*_mapping definitions riscv: Don't output a bogus mmu-type on a no MMU kernel riscv: atomic: Add custom conditional atomic operation implementation riscv: atomic: Optimize dec_if_positive functions riscv: atomic: Cleanup unnecessary definition RISC-V: Load purgatory in kexec_file RISC-V: Add purgatory RISC-V: Support for kexec_file on panic RISC-V: Add kexec_file support RISC-V: use memcpy for kexec_file mode kexec_file: Fix kexec_file.c build error for riscv platform riscv: compat: Add COMPAT Kbuild skeletal support riscv: compat: ptrace: Add compat_arch_ptrace implement riscv: compat: signal: Add rt_frame implementation riscv: add memory-type errata for T-Head ...

net: SO_RCVMARK socket option for SO_MARK with recvmsg()

2022-04-28T20:08:15+00:00

Adding a new socket option, SO_RCVMARK, to indicate that SO_MARK should be included in the ancillary data returned by recvmsg(). Renamed the sock_recv_ts_and_drops() function to sock_recv_cmsgs(). Signed-off-by: Erin MacNeil Reviewed-by: Eric Dumazet Reviewed-by: David Ahern Acked-by: Marc Kleine-Budde Link: https://lore.kernel.org/r/20220427200259.2564-1-lnx.erin@gmail.com Signed-off-by: Jakub Kicinski

syscalls: compat: Fix the missing part for __SYSCALL_COMPAT

2022-04-26T20:36:01+00:00

Make "uapi asm unistd.h" could be used for architectures' COMPAT mode. The __SYSCALL_COMPAT is first used in riscv. Signed-off-by: Guo Ren Signed-off-by: Guo Ren Reviewed-by: Arnd Bergmann Reviewed-by: Christoph Hellwig Tested-by: Heiko Stuebner Link: https://lore.kernel.org/r/20220405071314.3225832-8-guoren@kernel.org Signed-off-by: Palmer Dabbelt

uapi: always define F_GETLK64/F_SETLK64/F_SETLKW64 in fcntl.h

2022-04-26T20:35:20+00:00

The F_GETLK64/F_SETLK64/F_SETLKW64 fcntl opcodes are only implemented for the 32-bit syscall APIs, but are also needed for compat handling on 64-bit kernels. Consolidate them in unistd.h instead of definining the internal compat definitions in compat.h, which is rather error prone (e.g. parisc gets the values wrong currently). Note that before this change they were never visible to userspace due to the fact that CONFIG_64BIT is only set for kernel builds. Signed-off-by: Christoph Hellwig Signed-off-by: Guo Ren Reviewed-by: Arnd Bergmann Tested-by: Heiko Stuebner Link: https://lore.kernel.org/r/20220405071314.3225832-3-guoren@kernel.org Signed-off-by: Palmer Dabbelt