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| author |   Andi Kleen <ak@suse.de> | 2007-05-02 19:27:20 +0200 |
|---|---|---|
| committer |   Andi Kleen <andi@basil.nowhere.org> | 2007-05-02 19:27:20 +0200 |
| commit | 3671df8572a299acff9c9cac2bf7279ee614d154 (patch) | |
| tree | e92e13da85eee016ade75e2f46445d47a4d3d143 /include/asm-i386/cpufeature.h | |
| parent | [PATCH] i386: Verify important CPUID bits in real mode (diff) | |
| download | linux-dev-3671df8572a299acff9c9cac2bf7279ee614d154.tar.xz linux-dev-3671df8572a299acff9c9cac2bf7279ee614d154.zip | |
[PATCH] i386: Evaluate constant cpu features at runtime
Redefine cpu_has() to evaluate cpu features already checked in early
boot at compile time. This way the compiler might eliminate some dead code.
Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'include/asm-i386/cpufeature.h')
| -rw-r--r-- | include/asm-i386/cpufeature.h | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/include/asm-i386/cpufeature.h b/include/asm-i386/cpufeature.h index e66d004aa651..20e849ae6ddc 100644 --- a/include/asm-i386/cpufeature.h +++ b/include/asm-i386/cpufeature.h @@ -106,8 +106,12 @@ #define X86_FEATURE_LAHF_LM (6*32+ 0) /* LAHF/SAHF in long mode */ #define X86_FEATURE_CMP_LEGACY (6*32+ 1) /* If yes HyperThreading not valid */ -#define cpu_has(c, bit) test_bit(bit, (c)->x86_capability) -#define boot_cpu_has(bit) test_bit(bit, boot_cpu_data.x86_capability) +#define cpu_has(c, bit) \ + ((__builtin_constant_p(bit) && (bit) < 32 && \ + (1UL << (bit)) & REQUIRED_MASK1) ? \ + 1 : \ + test_bit(bit, (c)->x86_capability)) +#define boot_cpu_has(bit) cpu_has(&boot_cpu_data, bit) #define cpu_has_fpu boot_cpu_has(X86_FEATURE_FPU) #define cpu_has_vme boot_cpu_has(X86_FEATURE_VME) |