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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-06-14 16:16:10 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-06-16 14:15:46 +1000
commit2fae0a524b193e200b71778407ad29b22417056a (patch)
treeea7a613377caf837b0cb6ac3c715e7d5a27636ea /arch/powerpc
parent48c931125bf228a529b8d05218e9fdda899dfa93 (diff)
downloadop-kernel-dev-2fae0a524b193e200b71778407ad29b22417056a.zip
op-kernel-dev-2fae0a524b193e200b71778407ad29b22417056a.tar.gz
powerpc: Add memory clobber to mtspr()
Without this clobber, mtspr can be re-ordered by gcc vs. surrounding memory accesses. While this might be ok for some cases, it's not in others and I'm not confident that all callers get it right (In fact I'm sure some of them don't). So for now, let's make mtspr() itself contain a memory clobber until we can audit and fix everything, at which point we can remove it if we think it's worth doing so. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/include/asm/reg.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index a3c28e4..1170267 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -755,7 +755,8 @@
#define mfspr(rn) ({unsigned long rval; \
asm volatile("mfspr %0," __stringify(rn) \
: "=r" (rval)); rval;})
-#define mtspr(rn, v) asm volatile("mtspr " __stringify(rn) ",%0" : : "r" (v))
+#define mtspr(rn, v) asm volatile("mtspr " __stringify(rn) ",%0" : : "r" (v)\
+ : "memory")
#ifdef __powerpc64__
#ifdef CONFIG_PPC_CELL
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