diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h
index efb74fd5156e..b1066b9fb5f8 100644
--- a/arch/s390/include/asm/bug.h
+++ b/arch/s390/include/asm/bug.h
@@ -52,6 +52,10 @@
 	unreachable();					\
 } while (0)
 
+#define __WARN() do {					\
+	__EMIT_BUG(BUGFLAG_WARNING);			\
+} while (0)
+
 #define WARN_ON(x) ({					\
 	int __ret_warn_on = !!(x);			\
 	if (__builtin_constant_p(__ret_warn_on)) {	\