diff options
Diffstat (limited to 'arch/x86/include/asm/cpufeature.h')
| -rw-r--r-- | arch/x86/include/asm/cpufeature.h | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index ce95b8cbd229..1d337c51f7e6 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -112,8 +112,9 @@ extern const char * const x86_bug_flags[NBUGINTS*32]; test_cpu_cap(c, bit)) #define this_cpu_has(bit) \ - (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \ - x86_this_cpu_test_bit(bit, (unsigned long *)&cpu_info.x86_capability)) + (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 : \ + x86_this_cpu_test_bit(bit, \ + (unsigned long __percpu *)&cpu_info.x86_capability)) /* * This macro is for detection of features which need kernel @@ -155,11 +156,14 @@ extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit); #else /* - * Static testing of CPU features. Used the same as boot_cpu_has(). - * These will statically patch the target code for additional - * performance. + * Static testing of CPU features. Used the same as boot_cpu_has(). It + * statically patches the target code for additional performance. Use + * static_cpu_has() only in fast paths, where every cycle counts. Which + * means that the boot_cpu_has() variant is already fast enough for the + * majority of cases and you should stick to using it as it is generally + * only two instructions: a RIP-relative MOV and a TEST. */ -static __always_inline __pure bool _static_cpu_has(u16 bit) +static __always_inline bool _static_cpu_has(u16 bit) { asm_volatile_goto("1: jmp 6f\n" "2:\n" |