diff --git a/arch/um/Makefile-x86_64 b/arch/um/Makefile-x86_64
index dffd1184c956cca4314eb4c1127f30cbaf373185..9558a7cf34d599f8eda369838ffda69bba6ec646 100644
--- a/arch/um/Makefile-x86_64
+++ b/arch/um/Makefile-x86_64
@@ -11,6 +11,7 @@ USER_CFLAGS += -fno-builtin -m64
 CHECKFLAGS  += -m64
 AFLAGS += -m64
 LDFLAGS += -m elf_x86_64
+CPPFLAGS += -m64
 
 ELF_ARCH := i386:x86-64
 ELF_FORMAT := elf64-x86-64
diff --git a/arch/um/kernel/vmlinux.lds.S b/arch/um/kernel/vmlinux.lds.S
index 72acdce205e0a3eff5d6ae6cdbdd73a20c22a952..f8aeb448aab62ba76584f9c0e497e1897e490c6b 100644
--- a/arch/um/kernel/vmlinux.lds.S
+++ b/arch/um/kernel/vmlinux.lds.S
@@ -1,5 +1,3 @@
-/* in case the preprocessor is a 32bit one */
-#undef i386
 #ifdef CONFIG_LD_SCRIPT_STATIC
 #include "uml.lds.S"
 #else