diff options
| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2025-04-10 13:58:35 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-04-13 09:52:42 +0200 |
| commit | 7b3169dfa4ba1b1898d4bdfad6ddabbc9e8a57ed (patch) | |
| tree | 18ec40e50422cfc31e8434e64c05d0fff0109520 | |
| parent | d51faee4bd63b3b02fa6f56210ec0d84c5ccb680 (diff) | |
objtool, x86/hweight: Remove ANNOTATE_IGNORE_ALTERNATIVE
Since objtool's inception, frame pointer warnings have been manually
silenced for __arch_hweight*() to allow those functions' inline asm to
avoid using ASM_CALL_CONSTRAINT.
The potentially dubious reasoning for that decision over nine years ago
was that since !X86_FEATURE_POPCNT is exceedingly rare, it's not worth
hurting the code layout for a function call that will never happen on
the vast majority of systems.
However, those functions actually started using ASM_CALL_CONSTRAINT with
the following commit:
194a613088a8 ("x86/hweight: Use ASM_CALL_CONSTRAINT in inline asm()")
And rightfully so, as it makes the code correct. ASM_CALL_CONSTRAINT
will soon have no effect for non-FP configs anyway.
With ASM_CALL_CONSTRAINT in place, ANNOTATE_IGNORE_ALTERNATIVE no longer
has a purpose for the hweight functions. Remove it.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/e7070dba3278c90f1a836b16157dcd34ccd21e21.1744318586.git.jpoimboe@kernel.org
| -rw-r--r-- | arch/x86/include/asm/arch_hweight.h | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/arch/x86/include/asm/arch_hweight.h b/arch/x86/include/asm/arch_hweight.h index cbc6157f0b4b..b5982b94bdba 100644 --- a/arch/x86/include/asm/arch_hweight.h +++ b/arch/x86/include/asm/arch_hweight.h @@ -16,8 +16,7 @@ static __always_inline unsigned int __arch_hweight32(unsigned int w) { unsigned int res; - asm_inline (ALTERNATIVE(ANNOTATE_IGNORE_ALTERNATIVE - "call __sw_hweight32", + asm_inline (ALTERNATIVE("call __sw_hweight32", "popcntl %[val], %[cnt]", X86_FEATURE_POPCNT) : [cnt] "=" REG_OUT (res), ASM_CALL_CONSTRAINT : [val] REG_IN (w)); @@ -46,8 +45,7 @@ static __always_inline unsigned long __arch_hweight64(__u64 w) { unsigned long res; - asm_inline (ALTERNATIVE(ANNOTATE_IGNORE_ALTERNATIVE - "call __sw_hweight64", + asm_inline (ALTERNATIVE("call __sw_hweight64", "popcntq %[val], %[cnt]", X86_FEATURE_POPCNT) : [cnt] "=" REG_OUT (res), ASM_CALL_CONSTRAINT : [val] REG_IN (w)); |