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[PATCH] i386: Evaluate constant cpu features at runtime

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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>
This commit is contained in:
Andi Kleen 2007-05-02 19:27:20 +02:00 committed by Andi Kleen
parent c7f81c9453
commit 3671df8572
1 changed files with 6 additions and 2 deletions
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8
include/asm-i386/cpufeature.h
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@ -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)