linux-stable.git/tools/include/linux/compiler.h, branch v6.18.50

tools/compiler: match glibc 2.42 definition of __attribute_const__

2026-09-07T15:22:23+00:00

commit 8700a4761beb219873956666cf91776a2c61e698 upstream.

glibc 2.42 added __attribute_const__ to sys/cdefs.h:

    # define __attribute_const__ __attribute__ ((__const__))

GCC 15 warns when a macro is redefined to a different replacement list
(-Wbuiltin-macro-redefined). Since host tool Makefiles (resolve_btfids,
objtool) pass -Werror, this conflict becomes fatal.

The warning is suppressed on standard native builds because GCC treats
/usr/include as a system header path (-isystem), and macro-redefinition
warnings from system headers are silently suppressed by GCC. It fires
when glibc headers are on a regular include path (-I) instead, which
is the case in cross-compilation setups such as NixOS, where the
sysroot's glibc is passed explicitly via -I rather than -isystem.

Per (C11 6.10.3), identical replacement lists are accepted silently.
Match the glibc definition exactly, including the space before "((", so
the redefinition is accepted without warning regardless of whether
glibc headers are treated as system or non-system includes.

Link: https://lore.kernel.org/20260701200635.3992767-1-rkr0k0r@gmail.com
Signed-off-by: Joy H.J. Lee 
Cc: Nathan Chancellor 
Cc: David Laight 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

tools headers: Add stub definition for __iomem

2025-08-27T18:14:06+00:00

Add an empty definition for __iomem so that kernel headers that use
__iomem can be imported into tools/include/ with less modifications.

Acked-by: Shuah Khan 
Signed-off-by: David Matlack 
Link: https://lore.kernel.org/r/20250822212518.4156428-15-dmatlack@google.com
Signed-off-by: Alex Williamson

tools headers: Syncronize linux/build_bug.h with the kernel sources

2025-06-16T17:05:11+00:00

To pick up the changes in:

  243c90e917f5cfc9 ("build_bug.h: more user friendly error messages in BUILD_BUG_ON_ZERO()")

This also needed to pick the __BUILD_BUG_ON_ZERO_MSG() in
linux/compiler.h, that needed to be polished to avoid hitting old clang
problems with _Static_assert on arrays of structs:

  Debian clang version 11.0.1-2~deb10u1

  Debian clang version 11.0.1-2~deb10u1
  $ make NO_LIBTRACEEVENT=1 ARCH= CROSS_COMPILE= EXTRA_CFLAGS= -C tools/perf O=/tmp/build/perf CC=clang
  
  btf_dump.c:895:18: error: type name does not allow storage class to be specified
          for (i = 0; i < ARRAY_SIZE(pads); i++) {
                          ^
  /git/perf-6.16.0-rc1/tools/include/linux/kernel.h:91:59: note: expanded from macro 'ARRAY_SIZE'
  #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
                                                            ^
  /git/perf-6.16.0-rc1/tools/include/linux/compiler-gcc.h:26:28: note: expanded from macro '__must_be_array'
  #define __must_be_array(a)      BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
                                  ^
  /git/perf-6.16.0-rc1/tools/include/linux/build_bug.h:17:2: note: expanded from macro 'BUILD_BUG_ON_ZERO'
          __BUILD_BUG_ON_ZERO_MSG(e, ##__VA_ARGS__, #e " is true")
          ^
  /git/perf-6.16.0-rc1/tools/include/linux/compiler.h:248:67: note: expanded from macro '__BUILD_BUG_ON_ZERO_MSG'
  #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
                                                                    ^
  /usr/include/x86_64-linux-gnu/sys/cdefs.h:438:5: note: expanded from macro '_Static_assert'
      extern int (*__Static_assert_function (void)) \
      ^

These also failed:

toolsbuilder@five:~$ grep FAIL dm.log/summary | grep clang
   1    72.87 almalinux:8    : FAIL clang version 19.1.7 ( 19.1.7-2.module_el8.10.0+3990+33d0d926)
  15    73.39 centos:stream  : FAIL clang version 17.0.6 (Red Hat 17.0.6-1.module_el8+767+9fa966b8)
  36    87.14 opensuse:15.4  : FAIL clang version 15.0.7
  37    80.08 opensuse:15.5  : FAIL clang version 15.0.7
  40    72.12 oraclelinux:8  : FAIL clang version 16.0.6 (Red Hat 16.0.6-2.0.1.module+el8.9.0+90129+d3ee8717)
  42    74.12 rockylinux:8   : FAIL clang version 16.0.6 (Red Hat 16.0.6-2.module+el8.9.0+1651+e10a8f6d)
toolsbuilder@five:~$

This addresses this perf build warning:

  Warning: Kernel ABI header differences:
    diff -u tools/include/linux/build_bug.h include/linux/build_bug.h

Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Namhyung Kim 
Cc: Vincent Mailhol 
Cc: Yury Norov 
Link: https://lore.kernel.org/r/aEszb7SSIJB6Lp6f@x1
Signed-off-by: Arnaldo Carvalho de Melo

tools headers compiler: Pick the const_true() define from the kernel sources

2025-05-20T15:57:19+00:00

The sync of include/linux/bits.h with the kernel sources will make use
of this define, so add it to the tools/include/linux/compiler. variant
used to build tools/ living code.

Acked-by: Vincent Mailhol 
Acked-by: Yury Norov [NVIDIA] 
Cc: Adrian Hunter 
Cc: Ian Rogers 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Namhyung Kim 
Link: https://lore.kernel.org/r/20250519214126.1652491-7-acme@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

Merge tag 'memblock-v6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock

2024-09-25T18:35:19+00:00

Pull memblock updates from Mike Rapoport:

 - new memblock_estimated_nr_free_pages() helper to replace
   totalram_pages() which is less accurate when
   CONFIG_DEFERRED_STRUCT_PAGE_INIT is set

 - fixes for memblock tests

* tag 'memblock-v6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
  s390/mm: get estimated free pages by memblock api
  kernel/fork.c: get estimated free pages by memblock api
  mm/memblock: introduce a new helper memblock_estimated_nr_free_pages()
  memblock test: fix implicit declaration of function 'strscpy'
  memblock test: fix implicit declaration of function 'isspace'
  memblock test: fix implicit declaration of function 'memparse'
  memblock test: add the definition of __setup()
  memblock test: fix implicit declaration of function 'virt_to_phys'
  tools/testing: abstract two init.h into common include directory
  memblock tests: include export.h in linkage.h as kernel dose
  memblock tests: include memory_hotplug.h in mmzone.h as kernel dose

arm64: vDSO: Wire up getrandom() vDSO implementation

2024-09-13T15:28:36+00:00

Hook up the generic vDSO implementation to the aarch64 vDSO data page.
The _vdso_rng_data required data is placed within the _vdso_data vvar
page, by using a offset larger than the vdso_data.

The vDSO function requires a ChaCha20 implementation that does not write
to the stack, and that can do an entire ChaCha20 permutation.  The one
provided uses NEON on the permute operation, with a fallback to the
syscall for chips that do not support AdvSIMD.

This also passes the vdso_test_chacha test along with
vdso_test_getrandom. The vdso_test_getrandom bench-single result on
Neoverse-N1 shows:

   vdso: 25000000 times in 0.783884250 seconds
   libc: 25000000 times in 8.780275399 seconds
syscall: 25000000 times in 8.786581518 seconds

A small fixup to arch/arm64/include/asm/mman.h was required to avoid
pulling kernel code into the vDSO, similar to what's already done in
arch/arm64/include/asm/rwonce.h.

Signed-off-by: Adhemerval Zanella 
Reviewed-by: Ard Biesheuvel 
Acked-by: Will Deacon 
Signed-off-by: Jason A. Donenfeld

tools/testing: abstract two init.h into common include directory

2024-08-06T05:17:50+00:00

Currently we have two test suits define its own init.h. This is a little
redundant.

Let's create a init.h in common include directory and merge these two
into it.

Signed-off-by: Wei Yang 
CC: Mike Rapoport 
CC: Liam R. Howlett 
Link: https://lore.kernel.org/r/20240712035138.24674-3-richard.weiyang@gmail.com
Signed-off-by: Mike Rapoport (Microsoft)

selftests/bpf: Add uretprobe syscall test for regs integrity

2024-06-11T23:44:28+00:00

Add uretprobe syscall test that compares register values before
and after the uretprobe is hit. It also compares the register
values seen from attached bpf program.

Link: https://lore.kernel.org/all/20240611112158.40795-6-jolsa@kernel.org/

Acked-by: Andrii Nakryiko 
Reviewed-by: Masami Hiramatsu (Google) 
Signed-off-by: Jiri Olsa 
Signed-off-by: Masami Hiramatsu (Google)

selftests/bpf: Mark uprobe trigger functions with nocf_check attribute

2024-03-22T17:01:17+00:00

Some distros seem to enable the -fcf-protection=branch by default,
which breaks our setup on first instruction of uprobe trigger
functions and place there endbr64 instruction.

Marking them with nocf_check attribute to skip that.

Ignoring unknown attribute warning in gcc for bench objects, because
nocf_check can be used only when -fcf-protection=branch is enabled,
otherwise we get a warning and break compilation.

Signed-off-by: Jiri Olsa 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20240322134936.1075395-1-jolsa@kernel.org

compiler.h: move __is_constexpr() to compiler.h

2023-10-18T21:43:22+00:00

Prior to f747e6667ebb2 __is_constexpr() was in its only user minmax.h. 
That commit moved it to const.h - but that file just defines ULL(x) and
UL(x) so that constants can be defined for .S and .c files.

So apart from the word 'const' it wasn't really a good location.  Instead
move the definition to compiler.h just before the similar

  is_signed_type() and is_unsigned_type().

This may not be a good long-term home, but the three definitions belong
together.

Link: https://lkml.kernel.org/r/2a6680bbe2e84459816a113730426782@AcuMS.aculab.com
Signed-off-by: David Laight 
Reviewed-by: Kees Cook 
Cc: Arnd Bergmann 
Cc: Bart Van Assche 
Cc: Nathan Chancellor 
Cc: Nick Desaulniers 
Cc: Rasmus Villemoes 
Cc: Steven Rostedt (Google) 
Signed-off-by: Andrew Morton