diff --git a/drivers/firmware/efi/libstub/string.c b/drivers/firmware/efi/libstub/string.c
index 1ac2f8764715..5d13e43869ee 100644
--- a/drivers/firmware/efi/libstub/string.c
+++ b/drivers/firmware/efi/libstub/string.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/ctype.h>
+#include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/string.h>