diff options
| author | Uros Bizjak <ubizjak@gmail.com> | 2025-09-07 20:33:38 +0200 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2025-09-08 15:38:06 +0200 |
| commit | c6c973dbfa5e34b1572bcd1852adcad1b5d08fab (patch) | |
| tree | d7f0dfbf593ee77c79d6d3efe69c5877c446de98 /arch/x86/include/asm/rmwcc.h | |
| parent | 13bdfb53aa04eeb8022af87288c5bc0a5d13a834 (diff) | |
x86/asm: Remove code depending on __GCC_ASM_FLAG_OUTPUTS__
The minimum supported GCC version is 8.1, which supports flag output operands
and always defines __GCC_ASM_FLAG_OUTPUTS__ macro.
Remove code depending on __GCC_ASM_FLAG_OUTPUTS__ and use the "=@ccCOND" flag
output operand directly.
Use the equivalent "=@ccz" instead of "=@cce" flag output operand for
CMPXCHG8B and CMPXCHG16B instructions. These instructions set a single flag
bit - the Zero flag - and "=@ccz" is used to distinguish the CC user from
comparison instructions, where set ZERO flag indeed means that the values are
equal.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20250905121723.GCaLrU04lP2A50PT-B@fat_crate.local
Diffstat (limited to 'arch/x86/include/asm/rmwcc.h')
| -rw-r--r-- | arch/x86/include/asm/rmwcc.h | 26 |
1 files changed, 2 insertions, 24 deletions
diff --git a/arch/x86/include/asm/rmwcc.h b/arch/x86/include/asm/rmwcc.h index 3821ee3fae35..54c8fc430684 100644 --- a/arch/x86/include/asm/rmwcc.h +++ b/arch/x86/include/asm/rmwcc.h @@ -6,37 +6,15 @@ #define __CLOBBERS_MEM(clb...) "memory", ## clb -#ifndef __GCC_ASM_FLAG_OUTPUTS__ - -/* Use asm goto */ - -#define __GEN_RMWcc(fullop, _var, cc, clobbers, ...) \ -({ \ - bool c = false; \ - asm goto (fullop "; j" #cc " %l[cc_label]" \ - : : [var] "m" (_var), ## __VA_ARGS__ \ - : clobbers : cc_label); \ - if (0) { \ -cc_label: c = true; \ - } \ - c; \ -}) - -#else /* defined(__GCC_ASM_FLAG_OUTPUTS__) */ - -/* Use flags output or a set instruction */ - #define __GEN_RMWcc(fullop, _var, cc, clobbers, ...) \ ({ \ bool c; \ - asm_inline volatile (fullop CC_SET(cc) \ - : [var] "+m" (_var), CC_OUT(cc) (c) \ + asm_inline volatile (fullop \ + : [var] "+m" (_var), "=@cc" #cc (c) \ : __VA_ARGS__ : clobbers); \ c; \ }) -#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) */ - #define GEN_UNARY_RMWcc_4(op, var, cc, arg0) \ __GEN_RMWcc(op " " arg0, var, cc, __CLOBBERS_MEM()) |