diff --git a/xen/include/asm-arm/arm32/cmpxchg.h b/xen/include/asm-arm/arm32/cmpxchg.h
index 0770f272ee99..3ef1e5c63276 100644
--- a/xen/include/asm-arm/arm32/cmpxchg.h
+++ b/xen/include/asm-arm/arm32/cmpxchg.h
@@ -112,23 +112,12 @@ static always_inline unsigned long __cmpxchg(volatile void *ptr,
 					     unsigned long new,
 					     int size)
 {
+	smp_mb();
 	if (!__int_cmpxchg(ptr, &old, new, size, false, 0))
 		ASSERT_UNREACHABLE();
-
-	return old;
-}
-
-static always_inline unsigned long __cmpxchg_mb(volatile void *ptr,
-                                                unsigned long old,
-                                                unsigned long new, int size)
-{
-	unsigned long ret;
-
-	smp_mb();
-	ret = __cmpxchg(ptr, old, new, size);
 	smp_mb();
 
-	return ret;
+	return old;
 }
 
 /*
@@ -141,11 +130,11 @@ static always_inline unsigned long __cmpxchg_mb(volatile void *ptr,
  * The helper will return true when the update has succeeded (i.e no
  * timeout) and false if the update has failed.
  */
-static always_inline bool __cmpxchg_mb_timeout(volatile void *ptr,
-					       unsigned long *old,
-					       unsigned long new,
-					       int size,
-					       unsigned int max_try)
+static always_inline bool __cmpxchg_timeout(volatile void *ptr,
+					    unsigned long *old,
+					    unsigned long new,
+					    int size,
+					    unsigned int max_try)
 {
 	bool ret;
 
@@ -157,12 +146,6 @@ static always_inline bool __cmpxchg_mb_timeout(volatile void *ptr,
 }
 
 #define cmpxchg(ptr,o,n)						\
-	((__typeof__(*(ptr)))__cmpxchg_mb((ptr),			\
-					  (unsigned long)(o),		\
-					  (unsigned long)(n),		\
-					  sizeof(*(ptr))))
-
-#define cmpxchg_local(ptr,o,n)						\
 	((__typeof__(*(ptr)))__cmpxchg((ptr),				\
 				       (unsigned long)(o),		\
 				       (unsigned long)(n),		\
diff --git a/xen/include/asm-arm/arm64/cmpxchg.h b/xen/include/asm-arm/arm64/cmpxchg.h
index fc5c60f0bd74..f4a8c1ccba80 100644
--- a/xen/include/asm-arm/arm64/cmpxchg.h
+++ b/xen/include/asm-arm/arm64/cmpxchg.h
@@ -125,23 +125,12 @@ static always_inline unsigned long __cmpxchg(volatile void *ptr,
 					     unsigned long new,
 					     int size)
 {
+	smp_mb();
 	if (!__int_cmpxchg(ptr, &old, new, size, false, 0))
 		ASSERT_UNREACHABLE();
-
-	return old;
-}
-
-static always_inline unsigned long __cmpxchg_mb(volatile void *ptr,
-						unsigned long old,
-						unsigned long new, int size)
-{
-	unsigned long ret;
-
-	smp_mb();
-	ret = __cmpxchg(ptr, old, new, size);
 	smp_mb();
 
-	return ret;
+	return old;
 }
 
 /*
@@ -154,11 +143,11 @@ static always_inline unsigned long __cmpxchg_mb(volatile void *ptr,
  * The helper will return true when the update has succeeded (i.e no
  * timeout) and false if the update has failed.
  */
-static always_inline bool __cmpxchg_mb_timeout(volatile void *ptr,
-					       unsigned long *old,
-					       unsigned long new,
-					       int size,
-					       unsigned int max_try)
+static always_inline bool __cmpxchg_timeout(volatile void *ptr,
+					    unsigned long *old,
+					    unsigned long new,
+					    int size,
+					    unsigned int max_try)
 {
 	bool ret;
 
@@ -173,17 +162,8 @@ static always_inline bool __cmpxchg_mb_timeout(volatile void *ptr,
 ({ \
 	__typeof__(*(ptr)) __ret; \
 	__ret = (__typeof__(*(ptr))) \
-		__cmpxchg_mb((ptr), (unsigned long)(o), (unsigned long)(n), \
-			     sizeof(*(ptr))); \
-	__ret; \
-})
-
-#define cmpxchg_local(ptr, o, n) \
-({ \
-	__typeof__(*(ptr)) __ret; \
-	__ret = (__typeof__(*(ptr))) \
-		__cmpxchg((ptr), (unsigned long)(o), \
-			  (unsigned long)(n), sizeof(*(ptr))); \
+		__cmpxchg((ptr), (unsigned long)(o), (unsigned long)(n), \
+			  sizeof(*(ptr))); \
 	__ret; \
 })
 
diff --git a/xen/include/asm-arm/guest_atomics.h b/xen/include/asm-arm/guest_atomics.h
index af27cc627bf3..20347849e56c 100644
--- a/xen/include/asm-arm/guest_atomics.h
+++ b/xen/include/asm-arm/guest_atomics.h
@@ -96,14 +96,14 @@ static inline unsigned long __guest_cmpxchg(struct domain *d,
 
     perfc_incr(atomics_guest);
 
-    if ( __cmpxchg_mb_timeout(ptr, &oldval, new, size,
-                              this_cpu(guest_safe_atomic_max)) )
+    if ( __cmpxchg_timeout(ptr, &oldval, new, size,
+                           this_cpu(guest_safe_atomic_max)) )
         return oldval;
 
     perfc_incr(atomics_guest_paused);
 
     domain_pause_nosync(d);
-    oldval = __cmpxchg_mb(ptr, old, new, size);
+    oldval = __cmpxchg(ptr, old, new, size);
     domain_unpause(d);
 
     return oldval;
