Index: sys/arm/include/atomic-v4.h
===================================================================
--- sys/arm/include/atomic-v4.h
+++ sys/arm/include/atomic-v4.h
@@ -543,6 +543,13 @@
 	atomic_subtract_32((volatile uint32_t *)p, v);
 }
 
+static __inline u_long
+atomic_swap_long(volatile u_long *p, u_long v)
+{
+
+	return (atomic_swap_32((volatile uint32_t *)p, v));
+}
+
 /*
  * ARMv5 does not support SMP.  For both kernel and user modes, only a
  * compiler barrier is needed for fences, since CPU is always
Index: sys/arm/include/atomic-v6.h
===================================================================
--- sys/arm/include/atomic-v6.h
+++ sys/arm/include/atomic-v6.h
@@ -768,6 +768,13 @@
 	return (ret);
 }
 
+static __inline u_long
+atomic_swap_long(volatile u_long *p, u_long v)
+{
+
+	return (atomic_swap_32((volatile uint32_t *)p, v));
+}
+
 static __inline uint64_t
 atomic_swap_64(volatile uint64_t *p, uint64_t v)
 {
Index: sys/compat/linuxkpi/common/include/asm/atomic-long.h
===================================================================
--- sys/compat/linuxkpi/common/include/asm/atomic-long.h
+++ sys/compat/linuxkpi/common/include/asm/atomic-long.h
@@ -78,15 +78,7 @@
 static inline long
 atomic_long_xchg(atomic_long_t *v, long val)
 {
-#if defined(__i386__) || defined(__amd64__) || defined(__aarch64__)
 	return atomic_swap_long(&v->counter, val);
-#else
-	long ret = atomic_long_read(v);
-
-	while (!atomic_fcmpset_long(&v->counter, &ret, val))
-		;
-	return (ret);
-#endif
 }
 
 static inline long
Index: sys/compat/linuxkpi/common/include/asm/atomic.h
===================================================================
--- sys/compat/linuxkpi/common/include/asm/atomic.h
+++ sys/compat/linuxkpi/common/include/asm/atomic.h
@@ -128,15 +128,7 @@
 static inline int
 atomic_xchg(atomic_t *v, int i)
 {
-#if !defined(__mips__)
 	return (atomic_swap_int(&v->counter, i));
-#else
-	int ret = atomic_read(v);
-
-	while (!atomic_fcmpset_int(&v->counter, &ret, i))
-		;
-	return (ret);
-#endif
 }
 
 static inline int
Index: sys/mips/include/atomic.h
===================================================================
--- sys/mips/include/atomic.h
+++ sys/mips/include/atomic.h
@@ -755,4 +755,42 @@
 #define	atomic_store_rel_ptr	atomic_store_rel_long
 #define	atomic_readandclear_ptr	atomic_readandclear_long
 
+#define	ATOMIC_SWAP(sem,suf,dtype,before,after)			\
+static __inline dtype						\
+atomic_swap##sem##suff(volatile dtype *ptr, const dtype value)	\
+{								\
+	dtype retval;						\
+								\
+	if (before)						\
+		atomic_thread_fence_rel();			\
+	retval = *ptr;						\
+	while (!atomic_fcmpset_##suffix(ptr, &retval, value))	\
+		;						\
+	if (after)						\
+		atomic_thread_fence_acq();			\
+	return (retval);					\
+}
+
+ATOMIC_SWAP(,_int,u_int,0,0)
+ATOMIC_SWAP(_rel,_int,u_int,1,0)
+ATOMIC_SWAP(_ack,_int,u_int,0,1)
+
+ATOMIC_SWAP(,_32,uint32_t,0,0)
+ATOMIC_SWAP(_rel,_32,uint32_t,1,0)
+ATOMIC_SWAP(_ack,_32,uint32_t,0,1)
+
+#if defined(__mips_n64) || defined(__mips_n32)
+ATOMIC_SWAP(,_64,uint64_t,0,0)
+ATOMIC_SWAP(_rel,_64,uint64_t,1,0)
+ATOMIC_SWAP(_ack,_64,uint64_t,0,1)
+#endif
+
+ATOMIC_SWAP(,_long,u_long,0,0)
+ATOMIC_SWAP(_rel,_long,u_long,1,0)
+ATOMIC_SWAP(_ack,_long,u_long,0,1)
+
+ATOMIC_SWAP(,_ptr,void *,0,0)
+ATOMIC_SWAP(_rel,_ptr,void *,1,0)
+ATOMIC_SWAP(_ack,_ptr,void *,0,1)
+
 #endif /* ! _MACHINE_ATOMIC_H_ */
Index: sys/powerpc/include/atomic.h
===================================================================
--- sys/powerpc/include/atomic.h
+++ sys/powerpc/include/atomic.h
@@ -852,6 +852,9 @@
 #define	atomic_fetchadd_64	atomic_fetchadd_long
 #define	atomic_swap_long	atomic_swap_64
 #define	atomic_swap_ptr		atomic_swap_64
+#else
+#define	atomic_swap_long	atomic_swap_32
+#define	atomic_swap_ptr		atomic_swap_32
 #endif
 
 #undef __ATOMIC_REL