diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index c1cf59d..e022d0c 100644
--- a/arch/x86/include/asm/cmpxchg_32.h
+++ b/arch/x86/include/asm/cmpxchg_32.h
@@ -66,7 +66,7 @@ struct __xchg_dummy {
  * of the instruction set reference 24319102.pdf. We need
  * the reader side to see the coherent 64bit value.
  */
-static inline void __set_64bit(unsigned long long *ptr,
+static inline void __set_64bit(volatile unsigned long long *ptr,
 			       unsigned int low, unsigned int high)
 {
 	asm volatile("\n1:\t"