diff --git a/arch/x86_64/kernel/genapic_flat.c b/arch/x86_64/kernel/genapic_flat.c
index 01d3939e3a9c..ecb01eefdd27 100644
--- a/arch/x86_64/kernel/genapic_flat.c
+++ b/arch/x86_64/kernel/genapic_flat.c
@@ -8,6 +8,7 @@
  * Martin Bligh, Andi Kleen, James Bottomley, John Stultz, and
  * James Cleverdon.
  */
+#include <linux/errno.h>
 #include <linux/threads.h>
 #include <linux/cpumask.h>
 #include <linux/string.h>