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x86/bitops: Use TZCNT mnemonic in <asm/bitops.h>

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Current minimum required version of binutils is 2.25,
which supports TZCNT instruction mnemonic.

Replace "REP; BSF" in variable__{ffs,ffz}() function
with this proper mnemonic.

No functional change intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250325175215.330659-1-ubizjak@gmail.com
This commit is contained in:
Uros Bizjak 2025-03-25 18:52:01 +01:00 committed by Ingo Molnar
parent 3d66af75b0
commit 0717b1392d
1 changed files with 2 additions and 2 deletions
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4
arch/x86/include/asm/bitops.h
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@ -248,7 +248,7 @@ arch_test_bit_acquire(unsigned long nr, const volatile unsigned long *addr)
static __always_inline unsigned long variable__ffs(unsigned long word)
{
asm("rep; bsf %1,%0"
asm("tzcnt %1,%0"
: "=r" (word)
: ASM_INPUT_RM (word));
return word;
@ -267,7 +267,7 @@ static __always_inline unsigned long variable__ffs(unsigned long word)
static __always_inline unsigned long variable_ffz(unsigned long word)
{
asm("rep; bsf %1,%0"
asm("tzcnt %1,%0"
: "=r" (word)
: "r" (~word));
return word;