diff --git a/arch/um/Makefile-i386 b/arch/um/Makefile-i386
index b01dfb00e5f8..67290117d909 100644
--- a/arch/um/Makefile-i386
+++ b/arch/um/Makefile-i386
@@ -22,8 +22,8 @@ export LDFLAGS HOSTCFLAGS HOSTLDFLAGS UML_OBJCOPYFLAGS
 endif
 endif
 
-CFLAGS			+= -DCONFIG_X86_32
-AFLAGS			+= -DCONFIG_X86_32
+KBUILD_CFLAGS		+= -DCONFIG_X86_32
+KBUILD_AFLAGS		+= -DCONFIG_X86_32
 CONFIG_X86_32		:= y
 export CONFIG_X86_32