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authorH. Peter Anvin <hpa@linux.intel.com>2010-10-13 16:00:29 -0700
committerH. Peter Anvin <hpa@linux.intel.com>2010-10-13 16:00:29 -0700
commitd7acb92fea932ad2e7846480aeacddc2c03c8485 (patch)
tree21675108634aff8885cb881a476acf7146191b87 /arch/x86/include/asm/i387.h
parent7fe977dab356fbd7e86aa10bf83891761107c57c (diff)
downloadop-kernel-dev-d7acb92fea932ad2e7846480aeacddc2c03c8485.zip
op-kernel-dev-d7acb92fea932ad2e7846480aeacddc2c03c8485.tar.gz
x86-64, asm: If the assembler supports fxsave64, use it
Kbuild allows for us to probe for the existence of specific constructs in the assembler, use them to find out if we can use fxsave64 and permit the compiler to generate better code. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/include/asm/i387.h')
-rw-r--r--arch/x86/include/asm/i387.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
index a73a8d5..70f105b 100644
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -175,7 +175,7 @@ static inline void fpu_fxsave(struct fpu *fpu)
uses any extended registers for addressing, a second REX prefix
will be generated (to the assembler, rex64 followed by semicolon
is a separate instruction), and hence the 64-bitness is lost. */
-#if 0
+#ifdef CONFIG_AS_FXSAVEQ
/* Using "fxsaveq %0" would be the ideal choice, but is only supported
starting with gas 2.16. */
__asm__ __volatile__("fxsaveq %0"
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