x86: add memory clobber in switch_to()
Segment registers are reloaded, so we should add a memory clobber. The
generated assembly code is identical in my tests, but this doesn't mean
it is necessarily true for all configurations/compilers.
x86_64 already has the memory clobber.
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/asm-x86/system.h b/include/asm-x86/system.h
index 34505dd..b20c894 100644
--- a/include/asm-x86/system.h
+++ b/include/asm-x86/system.h
@@ -64,7 +64,10 @@
\
/* regparm parameters for __switch_to(): */ \
[prev] "a" (prev), \
- [next] "d" (next)); \
+ [next] "d" (next) \
+ \
+ : /* reloaded segment registers */ \
+ "memory"); \
} while (0)
/*