diff --git a/arch/sh/kernel/idle.c b/arch/sh/kernel/idle.c
index 3418c40f0099..114f0c4abeac 100644
--- a/arch/sh/kernel/idle.c
+++ b/arch/sh/kernel/idle.c
@@ -4,6 +4,7 @@
  *
  *  Copyright (C) 2002 - 2009  Paul Mundt
  */
+#include <linux/cpu.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/mm.h>