x86: Make alternative instruction pointers relative
This save a few bytes on x86-64 and means that future patches can
apply alternatives to unrelocated code.
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/ff64a6b9a1a3860ca4a7b8b6dc7b4754f9491cd7.1310563276.git.luto@mit.edu
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index bf535f9..23fb6d7 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -43,8 +43,8 @@
#endif
struct alt_instr {
- u8 *instr; /* original instruction */
- u8 *replacement;
+ s32 instr_offset; /* original instruction */
+ s32 repl_offset; /* offset to replacement instruction */
u16 cpuid; /* cpuid bit set for replacement */
u8 instrlen; /* length of original instruction */
u8 replacementlen; /* length of new instruction, <= instrlen */
@@ -84,8 +84,8 @@
"661:\n\t" oldinstr "\n662:\n" \
".section .altinstructions,\"a\"\n" \
_ASM_ALIGN "\n" \
- _ASM_PTR "661b\n" /* label */ \
- _ASM_PTR "663f\n" /* new instruction */ \
+ " .long 661b - .\n" /* label */ \
+ " .long 663f - .\n" /* new instruction */ \
" .word " __stringify(feature) "\n" /* feature bit */ \
" .byte 662b-661b\n" /* sourcelen */ \
" .byte 664f-663f\n" /* replacementlen */ \