diff --git a/sys/riscv/include/atomic.h b/sys/riscv/include/atomic.h
--- a/sys/riscv/include/atomic.h
+++ b/sys/riscv/include/atomic.h
@@ -37,10 +37,11 @@
 
 #include <sys/atomic_common.h>
 
-#define	fence()	__asm __volatile("fence" ::: "memory");
-#define	mb()	fence()
-#define	rmb()	fence()
-#define	wmb()	fence()
+#define	_fence(PRE, SUC)	__asm __volatile("fence "#PRE","#SUC ::: "memory");
+#define	fence()	_fence(rw, rw)
+#define	mb()	_fence(rw, rw)
+#define	rmb()	_fence(r, r)
+#define	wmb()	_fence(w, w)
 
 static __inline int atomic_cmpset_8(__volatile uint8_t *, uint8_t, uint8_t);
 static __inline int atomic_fcmpset_8(__volatile uint8_t *, uint8_t *, uint8_t);