diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 3e30147a537e..d9ecaa618430 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -5,6 +5,7 @@
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
+#include <linux/cpu.h>
 #include <linux/prctl.h>
 #include <linux/slab.h>
 #include <linux/sched.h>