Index: sys/riscv/include/atomic.h
===================================================================
--- sys/riscv/include/atomic.h
+++ sys/riscv/include/atomic.h
@@ -182,7 +182,7 @@
 			"bnez %1, 0b\n"
 		"1:"
 			: "=&r" (tmp), "=&r" (res), "+A" (*p)
-			: "rJ" (cmpval), "rJ" (newval)
+			: "rJ" ((long)(int32_t)cmpval), "rJ" (newval)
 			: "memory");
 
 	return (!res);
@@ -207,7 +207,7 @@
 			"sw   %0, %3\n"		/* Save old value */
 		"2:"
 			: "=&r" (tmp), "=&r" (res), "+A" (*p), "+A" (*cmpval)
-			: "rJ" (*cmpval), "rJ" (newval)
+			: "rJ" ((long)(int32_t)*cmpval), "rJ" (newval)
 			: "memory");
 
 	return (!res);