Add "memory" attribute in inline assembly language as a compiler
barrier to make sure 4.6.x GCC don't reorder mfmsr().

Signed-off-by: Tiejun Chen <tiejun.c...@windriver.com>
---
 arch/powerpc/include/asm/reg.h |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 559da19..578e5a0 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1016,7 +1016,8 @@
 /* Macros for setting and retrieving special purpose registers */
 #ifndef __ASSEMBLY__
 #define mfmsr()                ({unsigned long rval; \
-                       asm volatile("mfmsr %0" : "=r" (rval)); rval;})
+                       asm volatile("mfmsr %0" : "=r" (rval) : \
+                                               : "memory"); rval;})
 #ifdef CONFIG_PPC_BOOK3S_64
 #define __mtmsrd(v, l) asm volatile("mtmsrd %0," __stringify(l) \
                                     : : "r" (v) : "memory")
-- 
1.5.6

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