[PATCH] i386: Implement alternative_io for i386

Ported from x86-64.

Signed-off-by: Andi Kleen <ak@suse.de>

diff --git a/include/asm-i386/alternative.h b/include/asm-i386/alternative.h
index 2774673..0f70b37 100644 (file)
--- a/include/asm-i386/alternative.h
+++ b/include/asm-i386/alternative.h
@@ -82,6 +82,21 @@ static inline void alternatives_smp_switch(int smp) {}
                      "663:\n\t" newinstr "\n664:\n"   /* replacement */\
                      ".previous" :: "i" (feature), ##input)
 
+/* Like alternative_input, but with a single output argument */
+#define alternative_io(oldinstr, newinstr, feature, output, input...) \
+       asm volatile ("661:\n\t" oldinstr "\n662:\n"                    \
+                     ".section .altinstructions,\"a\"\n"               \
+                     "  .align 4\n"                                    \
+                     "  .long 661b\n"            /* label */           \
+                     "  .long 663f\n"            /* new instruction */ \
+                     "  .byte %c[feat]\n"        /* feature bit */     \
+                     "  .byte 662b-661b\n"       /* sourcelen */       \
+                     "  .byte 664f-663f\n"       /* replacementlen */  \
+                     ".previous\n"                                     \
+                     ".section .altinstr_replacement,\"ax\"\n"         \
+                     "663:\n\t" newinstr "\n664:\n"   /* replacement */ \
+                     ".previous" : output : [feat] "i" (feature), ##input)
+
 /*
  * Alternative inline assembly for SMP.
  *