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Commit 3671df85 authored by Andi Kleen's avatar Andi Kleen Committed by Andi Kleen
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[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: default avatarAndi Kleen <ak@suse.de>
parent c7f81c94

include/asm-i386/cpufeature.h

+6 −2
Original line number Original line Diff line number Diff line
@@ -106,8 +106,12 @@ 
#define X86_FEATURE_LAHF_LM	(6*32+ 0) /* LAHF/SAHF in long mode */

#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 X86_FEATURE_CMP_LEGACY	(6*32+ 1) /* If yes HyperThreading not valid */





#define cpu_has(c, bit)		test_bit(bit, (c)->x86_capability)

#define cpu_has(c, bit)					\

#define boot_cpu_has(bit)	test_bit(bit, boot_cpu_data.x86_capability)

	((__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_fpu		boot_cpu_has(X86_FEATURE_FPU)

#define cpu_has_vme		boot_cpu_has(X86_FEATURE_VME)

#define cpu_has_vme		boot_cpu_has(X86_FEATURE_VME)