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| author | Peter Zijlstra <peterz@infradead.org> | 2026-07-28 05:25:33 +0000 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-07-28 13:07:14 +0200 |
| commit | 775e0f2284554e24855c4372faeb957a5e515337 (patch) | |
| tree | 784d682df8342d07473d1daaff53ba6607dc60ea | |
| parent | 051f5d223dfc1806e216f60e4b29c1bf35f5c2d3 (diff) | |
| download | linux-next-775e0f2284554e24855c4372faeb957a5e515337.tar.gz linux-next-775e0f2284554e24855c4372faeb957a5e515337.zip | |
x86/runtime-const: Introduce runtime_const_mask_32()
Futex hash computation requires a mask operation with read-only after
init data that will be converted to a runtime constant in the subsequent
commit.
Introduce runtime_const_mask_32 to further optimize the mask operation
in the futex hash computation hot path.
[ prateek: Broke off the x86 chunk, commit message. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260227161841.GH606826@noisy.programming.kicks-ass.net
Link: https://patch.msgid.link/20260728052540.4728-2-kprateek.nayak@amd.com
| -rw-r--r-- | arch/x86/include/asm/runtime-const.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/x86/include/asm/runtime-const.h b/arch/x86/include/asm/runtime-const.h index 4cd94fdcb45e..b13f7036c1c9 100644 --- a/arch/x86/include/asm/runtime-const.h +++ b/arch/x86/include/asm/runtime-const.h @@ -41,6 +41,15 @@ :"+r" (__ret)); \ __ret; }) +#define runtime_const_mask_32(val, sym) ({ \ + typeof(0u+(val)) __ret = (val); \ + asm_inline("and $0x12345678, %k0\n1:\n" \ + ".pushsection runtime_mask_" #sym ",\"a\"\n\t"\ + ".long 1b - 4 - .\n" \ + ".popsection" \ + : "+r" (__ret)); \ + __ret; }) + #define runtime_const_init(type, sym) do { \ extern s32 __start_runtime_##type##_##sym[]; \ extern s32 __stop_runtime_##type##_##sym[]; \ @@ -65,6 +74,11 @@ static inline void __runtime_fixup_shift(void *where, unsigned long val) *(unsigned char *)where = val; } +static inline void __runtime_fixup_mask(void *where, unsigned long val) +{ + *(unsigned int *)where = val; +} + static inline void runtime_const_fixup(void (*fn)(void *, unsigned long), unsigned long val, s32 *start, s32 *end) { |