kernel/linux.git/include/linux/compiler-clang.h, branch v6.12.80

compiler-clang.h: define __SANITIZE_*__ macros only when undefined

2025-09-19T14:35:45+00:00

commit 3fac212fe489aa0dbe8d80a42a7809840ca7b0f9 upstream. Clang 22 recently added support for defining __SANITIZE__ macros similar to GCC [1], which causes warnings (or errors with CONFIG_WERROR=y or W=e) with the existing defines that the kernel creates to emulate this behavior with existing clang versions. In file included from :3: In file included from include/linux/compiler_types.h:171: include/linux/compiler-clang.h:37:9: error: '__SANITIZE_THREAD__' macro redefined [-Werror,-Wmacro-redefined] 37 | #define __SANITIZE_THREAD__ | ^ :352:9: note: previous definition is here 352 | #define __SANITIZE_THREAD__ 1 | ^ Refactor compiler-clang.h to only define the sanitizer macros when they are undefined and adjust the rest of the code to use these macros for checking if the sanitizers are enabled, clearing up the warnings and allowing the kernel to easily drop these defines when the minimum supported version of LLVM for building the kernel becomes 22.0.0 or newer. Link: https://lkml.kernel.org/r/20250902-clang-update-sanitize-defines-v1-1-cf3702ca3d92@kernel.org Link: https://github.com/llvm/llvm-project/commit/568c23bbd3303518c5056d7f03444dae4fdc8a9c [1] Signed-off-by: Nathan Chancellor Reviewed-by: Justin Stitt Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Bill Wendling Cc: Dmitriy Vyukov Cc: Marco Elver Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

clang: work around asm input constraint problems

2024-05-22T21:12:11+00:00

Work around clang problems with asm constraints that have multiple possibilities, particularly "g" and "rm". Clang seems to turn inputs like that into the most generic form, which is the memory input - but to make matters worse, clang won't even use a possible original memory location, but will spill the value to stack, and use the stack for the asm input. See https://github.com/llvm/llvm-project/issues/20571#issuecomment-980933442 for some explanation of why clang has this strange behavior, but the end result is that "g" and "rm" really end up generating horrid code. Link: https://github.com/llvm/llvm-project/issues/20571 Cc: Peter Zijlstra Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Thomas Gleixner Signed-off-by: Linus Torvalds

compiler-clang.h: update __diag_clang() macros for minimum version bump

2024-02-22T23:38:54+00:00

The minimum supported version of LLVM for building the kernel has been bumped to 13.0.1. Update the __diag_clang() macros for this bump. Link: https://lkml.kernel.org/r/20240125-bump-min-llvm-ver-to-13-0-1-v1-11-f5ff9bda41c5@kernel.org Signed-off-by: Nathan Chancellor Reviewed-by: Kees Cook Cc: Albert Ou Cc: "Aneesh Kumar K.V (IBM)" Cc: Ard Biesheuvel Cc: Borislav Petkov (AMD) Cc: Catalin Marinas Cc: Conor Dooley Cc: Dave Hansen Cc: Ingo Molnar Cc: Mark Rutland Cc: Masahiro Yamada Cc: Michael Ellerman Cc: "Naveen N. Rao" Cc: Nicholas Piggin Cc: Nicolas Schier Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Russell King Cc: Thomas Gleixner Cc: Will Deacon Signed-off-by: Andrew Morton

arch and include: update LLVM Phabricator links

2024-02-22T23:38:51+00:00

reviews.llvm.org was LLVM's Phabricator instances for code review. It has been abandoned in favor of GitHub pull requests. While the majority of links in the kernel sources still work because of the work Fangrui has done turning the dynamic Phabricator instance into a static archive, there are some issues with that work, so preemptively convert all the links in the kernel sources to point to the commit on GitHub. Most of the commits have the corresponding differential review link in the commit message itself so there should not be any loss of fidelity in the relevant information. Link: https://discourse.llvm.org/t/update-on-github-pull-requests/71540/172 Link: https://lkml.kernel.org/r/20240109-update-llvm-links-v1-2-eb09b59db071@kernel.org Signed-off-by: Nathan Chancellor Reviewed-by: Conor Dooley Reviewed-by: Kees Cook Acked-by: Fangrui Song Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Daniel Borkmann Cc: Mykola Lysenko Signed-off-by: Andrew Morton

compiler.h: unify __UNIQUE_ID

2023-10-04T17:41:56+00:00

commit 6f33d58794ef ("__UNIQUE_ID()") added a fallback definition of __UNIQUE_ID because gcc 4.2 and older did not support __COUNTER__. Also, this commit is effectively a revert of commit b41c29b0527c ("Kbuild: provide a __UNIQUE_ID for clang") which mentions clang 2.6+ supporting __COUNTER__. Documentation/process/changes.rst currently lists the minimum supported version of these compilers as: - gcc: 5.1 - clang: 11.0.0 It should be safe to say that __COUNTER__ is well supported by this point. Link: https://lkml.kernel.org/r/20230831-unique_id-v1-1-28bacd18eb1d@google.com Signed-off-by: Nick Desaulniers Cc: Arnd Bergmann Cc: Jan Beulich Cc: Luc Van Oostenryck Cc: Michal rarek Cc: Nathan Chancellor Cc: Paul Russel Cc: Tom Rix Signed-off-by: Andrew Morton

locking: Introduce __cleanup() based infrastructure

2023-06-26T09:14:18+00:00

Use __attribute__((__cleanup__(func))) to build: - simple auto-release pointers using __free() - 'classes' with constructor and destructor semantics for scope-based resource management. - lock guards based on the above classes. Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20230612093537.614161713%40infradead.org

Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-10-11T00:53:04+00:00

Pull MM updates from Andrew Morton: - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in linux-next for a couple of months without, to my knowledge, any negative reports (or any positive ones, come to that). - Also the Maple Tree from Liam Howlett. An overlapping range-based tree for vmas. It it apparently slightly more efficient in its own right, but is mainly targeted at enabling work to reduce mmap_lock contention. Liam has identified a number of other tree users in the kernel which could be beneficially onverted to mapletrees. Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat at [1]. This has yet to be addressed due to Liam's unfortunately timed vacation. He is now back and we'll get this fixed up. - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses clang-generated instrumentation to detect used-unintialized bugs down to the single bit level. KMSAN keeps finding bugs. New ones, as well as the legacy ones. - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of memory into THPs. - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support file/shmem-backed pages. - userfaultfd updates from Axel Rasmussen - zsmalloc cleanups from Alexey Romanov - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure - Huang Ying adds enhancements to NUMA balancing memory tiering mode's page promotion, with a new way of detecting hot pages. - memcg updates from Shakeel Butt: charging optimizations and reduced memory consumption. - memcg cleanups from Kairui Song. - memcg fixes and cleanups from Johannes Weiner. - Vishal Moola provides more folio conversions - Zhang Yi removed ll_rw_block() :( - migration enhancements from Peter Xu - migration error-path bugfixes from Huang Ying - Aneesh Kumar added ability for a device driver to alter the memory tiering promotion paths. For optimizations by PMEM drivers, DRM drivers, etc. - vma merging improvements from Jakub Matěn. - NUMA hinting cleanups from David Hildenbrand. - xu xin added aditional userspace visibility into KSM merging activity. - THP & KSM code consolidation from Qi Zheng. - more folio work from Matthew Wilcox. - KASAN updates from Andrey Konovalov. - DAMON cleanups from Kaixu Xia. - DAMON work from SeongJae Park: fixes, cleanups. - hugetlb sysfs cleanups from Muchun Song. - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core. Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1] * tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits) hugetlb: allocate vma lock for all sharable vmas hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer hugetlb: fix vma lock handling during split vma and range unmapping mglru: mm/vmscan.c: fix imprecise comments mm/mglru: don't sync disk for each aging cycle mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol mm: memcontrol: use do_memsw_account() in a few more places mm: memcontrol: deprecate swapaccounting=0 mode mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled mm/secretmem: remove reduntant return value mm/hugetlb: add available_huge_pages() func mm: remove unused inline functions from include/linux/mm_inline.h selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd selftests/vm: add thp collapse shmem testing selftests/vm: add thp collapse file and tmpfs testing selftests/vm: modularize thp collapse memory operations selftests/vm: dedup THP helpers mm/khugepaged: add tracepoint to hpage_collapse_scan_file() mm/madvise: add file and shmem support to MADV_COLLAPSE ...

kmsan: introduce __no_sanitize_memory and __no_kmsan_checks

2022-10-03T21:03:19+00:00

__no_sanitize_memory is a function attribute that instructs KMSAN to skip a function during instrumentation. This is needed to e.g. implement the noinstr functions. __no_kmsan_checks is a function attribute that makes KMSAN ignore the uninitialized values coming from the function's inputs, and initialize the function's outputs. Functions marked with this attribute can't be inlined into functions not marked with it, and vice versa. This behavior is overridden by __always_inline. __SANITIZE_MEMORY__ is a macro that's defined iff the file is instrumented with KMSAN. This is not the same as CONFIG_KMSAN, which is defined for every file. Link: https://lkml.kernel.org/r/20220915150417.722975-8-glider@google.com Signed-off-by: Alexander Potapenko Reviewed-by: Marco Elver Cc: Alexander Viro Cc: Alexei Starovoitov Cc: Andrey Konovalov Cc: Andrey Konovalov Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Christoph Hellwig Cc: Christoph Lameter Cc: David Rientjes Cc: Dmitry Vyukov Cc: Eric Biggers Cc: Eric Biggers Cc: Eric Dumazet Cc: Greg Kroah-Hartman Cc: Herbert Xu Cc: Ilya Leoshkevich Cc: Ingo Molnar Cc: Jens Axboe Cc: Joonsoo Kim Cc: Kees Cook Cc: Mark Rutland Cc: Matthew Wilcox Cc: Michael S. Tsirkin Cc: Pekka Enberg Cc: Peter Zijlstra Cc: Petr Mladek Cc: Stephen Rothwell Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Vegard Nossum Cc: Vlastimil Babka Signed-off-by: Andrew Morton

cfi: Switch to -fsanitize=kcfi

2022-09-26T17:13:13+00:00

Switch from Clang's original forward-edge control-flow integrity implementation to -fsanitize=kcfi, which is better suited for the kernel, as it doesn't require LTO, doesn't use a jump table that requires altering function references, and won't break cross-module function address equality. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook Tested-by: Kees Cook Tested-by: Nathan Chancellor Acked-by: Peter Zijlstra (Intel) Tested-by: Peter Zijlstra (Intel) Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220908215504.3686827-6-samitolvanen@google.com

cfi: Use __builtin_function_start

2022-04-13T19:16:00+00:00

Clang 14 added support for the __builtin_function_start function, which allows us to implement the function_nocfi macro without architecture-specific inline assembly and in a way that also works with static initializers. Change CONFIG_CFI_CLANG to depend on Clang >= 14, define function_nocfi using __builtin_function_start, and remove the arm64 inline assembly implementation. Link: https://github.com/llvm/llvm-project/commit/ec2e26eaf63558934f5b73a6e530edc453cf9508 Link: https://github.com/ClangBuiltLinux/linux/issues/1353 Signed-off-by: Sami Tolvanen Reviewed-by: Nick Desaulniers Reviewed-by: Mark Rutland Tested-by: Mark Rutland Acked-by: Will Deacon # arm64 Reviewed-by: Nathan Chancellor Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220405221618.633743-1-samitolvanen@google.com