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| author |   Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2019-07-20 07:07:56 +0300 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2019-07-20 07:07:56 +0300 |
| commit | c39f2d9db0fd81ea20bb5cce9b3f082ca63753e2 (patch) | |
| tree | 8e80ed5601b4fb8880a2ca8e08802bc8b1f850bd /arch/x86/include/asm/cpufeature.h | |
| parent | Merge branch 'next' into for-linus (diff) | |
| parent | Input: alps - fix a mismatch between a condition check and its comment (diff) | |
| download | linux-dev-c39f2d9db0fd81ea20bb5cce9b3f082ca63753e2.tar.xz linux-dev-c39f2d9db0fd81ea20bb5cce9b3f082ca63753e2.zip | |
Merge branch 'next' into for-linus
Prepare second round of input updates for 5.3 merge window.
Diffstat (limited to 'arch/x86/include/asm/cpufeature.h')
| -rw-r--r-- | arch/x86/include/asm/cpufeature.h | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index 0e56ff7e4848..1d337c51f7e6 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -156,11 +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" |