From e6428c3492a34ed728b6152cf073efb3250a6d94 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Mon, 19 May 2025 11:48:19 -0300 Subject: tools headers compiler: Pick the const_true() define from the kernel sources 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 --- tools/include/linux/compiler.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'tools/include/linux') diff --git a/tools/include/linux/compiler.h b/tools/include/linux/compiler.h index 9c05a59f0184..d627e66a04a6 100644 --- a/tools/include/linux/compiler.h +++ b/tools/include/linux/compiler.h @@ -81,6 +81,28 @@ #define __is_constexpr(x) \ (sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8))) +/* + * Similar to statically_true() but produces a constant expression + * + * To be used in conjunction with macros, such as BUILD_BUG_ON_ZERO(), + * which require their input to be a constant expression and for which + * statically_true() would otherwise fail. + * + * This is a trade-off: const_true() requires all its operands to be + * compile time constants. Else, it would always returns false even on + * the most trivial cases like: + * + * true || non_const_var + * + * On the opposite, statically_true() is able to fold more complex + * tautologies and will return true on expressions such as: + * + * !(non_const_var * 8 % 4) + * + * For the general case, statically_true() is better. + */ +#define const_true(x) __builtin_choose_expr(__is_constexpr(x), x, false) + #ifdef __ANDROID__ /* * FIXME: Big hammer to get rid of tons of: -- cgit v1.2.3 From e48b92f9e140ff632ad426c0a94e3630a61e45d8 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Mon, 19 May 2025 11:51:16 -0300 Subject: tools headers: Synchronize linux/bits.h with the kernel sources To pick up the changes in this cset: 0312e94abe484b9e ("treewide: fix typo 'unsigned __init128' -> 'unsigned __int128'") This addresses these perf build warnings: Warning: Kernel ABI header differences: diff -u tools/include/linux/bits.h include/linux/bits.h This required picking the const_true() define in linux/compiler.h as a prep patch as that macro is used in the new linux/bits.h Please see tools/include/uapi/README for further details. 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/20250519214126.1652491-8-acme@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/include/linux/bits.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'tools/include/linux') diff --git a/tools/include/linux/bits.h b/tools/include/linux/bits.h index 8de2914e6510..14fd0ca9a6cd 100644 --- a/tools/include/linux/bits.h +++ b/tools/include/linux/bits.h @@ -20,9 +20,8 @@ */ #if !defined(__ASSEMBLY__) #include -#define GENMASK_INPUT_CHECK(h, l) \ - (BUILD_BUG_ON_ZERO(__builtin_choose_expr( \ - __is_constexpr((l) > (h)), (l) > (h), 0))) +#include +#define GENMASK_INPUT_CHECK(h, l) BUILD_BUG_ON_ZERO(const_true((l) > (h))) #else /* * BUILD_BUG_ON_ZERO is not available in h files included from asm files, -- cgit v1.2.3