diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index 3cd8dd2..c1ea6bc 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -19,6 +19,7 @@
 AFLAGS		+= -m31
 UTS_MACHINE	:= s390
 STACK_SIZE	:= 8192
+CHECKFLAGS	+= -D__s390__
 endif
 
 ifdef CONFIG_ARCH_S390X
@@ -28,6 +29,7 @@
 AFLAGS		+= -m64
 UTS_MACHINE	:= s390x
 STACK_SIZE	:= 16384
+CHECKFLAGS	+= -D__s390__ -D__s390x__
 endif
 
 cflags-$(CONFIG_MARCH_G5)   += $(call cc-option,-march=g5)