diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index d156bfb..6643f3f 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -10,6 +10,7 @@
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/percpu.h>
+#include <linux/start_kernel.h>
 
 #include <asm/processor.h>
 #include <asm/proto.h>