diff options
| -rw-r--r-- | arch/x86/include/asm/cpufeature.h | 49 |
1 files changed, 5 insertions, 44 deletions
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index a261cf2e79075..9048c1bbc5198 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -129,17 +129,16 @@ extern const char * const x86_bug_flags[NBUGINTS*32]; * fast paths and boot_cpu_has() otherwise! */ -#if __GNUC__ >= 4 && defined(CONFIG_X86_FAST_FEATURE_TESTS) +#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_X86_FAST_FEATURE_TESTS) extern bool __static_cpu_has(u16 bit); /* * Static testing of CPU features. Used the same as boot_cpu_has(). - * These are only valid after alternatives have run, but will statically - * patch the target code for additional performance. + * These will statically patch the target code for additional + * performance. */ static __always_inline __pure bool _static_cpu_has(u16 bit) { -#ifdef CC_HAVE_ASM_GOTO asm_volatile_goto("1: jmp %l[t_dynamic]\n" "2:\n" ".skip -(((5f-4f) - (2b-1b)) > 0) * " @@ -172,45 +171,6 @@ static __always_inline __pure bool _static_cpu_has(u16 bit) return false; t_dynamic: return __static_cpu_has(bit); -#else - u8 flag; - /* Open-coded due to __stringify() in ALTERNATIVE() */ - asm volatile("1: movb $2,%0\n" - "2:\n" - ".section .altinstructions,\"a\"\n" - " .long 1b - .\n" /* src offset */ - " .long 3f - .\n" /* repl offset */ - " .word %P2\n" /* always replace */ - " .byte 2b - 1b\n" /* source len */ - " .byte 4f - 3f\n" /* replacement len */ - " .byte 0\n" /* pad len */ - ".previous\n" - ".section .discard,\"aw\",@progbits\n" - " .byte 0xff + (4f-3f) - (2b-1b)\n" /* size check */ - ".previous\n" - ".section .altinstr_replacement,\"ax\"\n" - "3: movb $0,%0\n" - "4:\n" - ".previous\n" - ".section .altinstructions,\"a\"\n" - " .long 1b - .\n" /* src offset */ - " .long 5f - .\n" /* repl offset */ - " .word %P1\n" /* feature bit */ - " .byte 4b - 3b\n" /* src len */ - " .byte 6f - 5f\n" /* repl len */ - " .byte 0\n" /* pad len */ - ".previous\n" - ".section .discard,\"aw\",@progbits\n" - " .byte 0xff + (6f-5f) - (4b-3b)\n" /* size check */ - ".previous\n" - ".section .altinstr_replacement,\"ax\"\n" - "5: movb $1,%0\n" - "6:\n" - ".previous\n" - : "=qm" (flag) - : "i" (bit), "i" (X86_FEATURE_ALWAYS)); - return (flag == 2 ? __static_cpu_has(bit) : flag); -#endif /* CC_HAVE_ASM_GOTO */ } #define static_cpu_has(bit) \ @@ -221,7 +181,8 @@ static __always_inline __pure bool _static_cpu_has(u16 bit) ) #else /* - * gcc 3.x is too stupid to do the static test; fall back to dynamic. + * Fall back to dynamic for gcc versions which don't support asm goto. Should be + * a minority now anyway. */ #define static_cpu_has(bit) boot_cpu_has(bit) #endif |