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authorBrian Gerst <brgerst@gmail.com>2009-11-25 14:18:26 -0500
committerIngo Molnar <mingo@elte.hu>2009-11-26 10:33:58 +0100
commit79b0379cee09b00ef309384aff652e328e438c79 (patch)
tree5a87d096d1f05b47f8372eda2523b1e1c830be23
parent3c93ca00eeeb774c7dd666cc7286a9e90c53e998 (diff)
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x86: Optimize loadsegment()
Zero the input register in the exception handler instead of using an extra register to pass in a zero value. Signed-off-by: Brian Gerst <brgerst@gmail.com> LKML-Reference: <1259176706-5908-1-git-send-email-brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/include/asm/system.h15
1 files changed, 8 insertions, 7 deletions
diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h
index 1a953e26401c..537395a2877a 100644
--- a/arch/x86/include/asm/system.h
+++ b/arch/x86/include/asm/system.h
@@ -156,18 +156,19 @@ extern void native_load_gs_index(unsigned);
* segment if something goes wrong..
*/
#define loadsegment(seg, value) \
+do { \
+ unsigned short __val = value; \
asm volatile("\n" \
"1:\t" \
"movl %k0,%%" #seg "\n" \
- "2:\n" \
".section .fixup,\"ax\"\n" \
- "3:\t" \
- "movl %k1, %%" #seg "\n\t" \
- "jmp 2b\n" \
+ "2:\t" \
+ "xorl %k0,%k0\n\t" \
+ "jmp 1b\n" \
".previous\n" \
- _ASM_EXTABLE(1b,3b) \
- : :"r" (value), "r" (0) : "memory")
-
+ _ASM_EXTABLE(1b, 2b) \
+ : "+r" (__val) : : "memory"); \
+} while (0)
/*
* Save a segment register away