powerpc: Add "memory" attribute for mfmsr()
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.chen@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: stable@vger.kernel.org
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 2baeb7c..6386086 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1025,7 +1025,8 @@
/* 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")