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| author | Uros Bizjak <ubizjak@gmail.com> | 2024-03-19 13:40:14 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2024-03-19 15:15:35 +0300 |
| commit | d689863c1a60b9936b47a34fa5c3330de374f4fc (patch) | |
| tree | a2f25a657e0f6e5d6c5b0be0f31c7e792d82931a /arch/x86/include/asm/cpufeature.h | |
| parent | 41cd2e1ee96e56401a18dbce6f42f0bdaebcbf3b (diff) | |
| download | linux-d689863c1a60b9936b47a34fa5c3330de374f4fc.tar.xz | |
x86/asm: Use %a instead of %P operand modifier in asm templates
The "P" asm operand modifier is a x86 target-specific modifier.
For x86_64, when used with a symbol reference, the "%P" modifier
emits "sym" instead of "sym(%rip)". This property is currently
used to issue bare symbol reference.
The generic "a" operand modifier should be used instead. The "a"
asm operand modifier substitutes a memory reference, with the
actual operand treated as address. For x86_64, when a symbol is
provided, the "a" modifier emits "sym(%rip)" instead of "sym",
enabling shorter %rip-relative addressing.
Also note that unlike GCC, clang emits %rip-relative symbol
reference with "P" asm operand modifier, so the patch also unifies
symbol handling with both compilers.
No functional changes intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lore.kernel.org/r/20240319104418.284519-4-ubizjak@gmail.com
Diffstat (limited to 'arch/x86/include/asm/cpufeature.h')
| -rw-r--r-- | arch/x86/include/asm/cpufeature.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index fa938ed96506..daae5c6e7d0e 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -172,7 +172,7 @@ static __always_inline bool _static_cpu_has(u16 bit) ALTERNATIVE_TERNARY("jmp 6f", %c[feature], "", "jmp %l[t_no]") ".pushsection .altinstr_aux,\"ax\"\n" "6:\n" - " testb %[bitnum]," _ASM_RIP(%P[cap_byte]) "\n" + " testb %[bitnum], %a[cap_byte]\n" " jnz %l[t_yes]\n" " jmp %l[t_no]\n" ".popsection\n" |