diff --git a/xen/arch/powerpc/of-devtree.h b/xen/arch/powerpc/of-devtree.h
index 21e96ef911..09e836eff4 100644
--- a/xen/arch/powerpc/of-devtree.h
+++ b/xen/arch/powerpc/of-devtree.h
@@ -22,6 +22,7 @@
 #define _OF_DEVTREE_H
 
 #include <xen/types.h>
+#include <xen/string.h>
 #include <public/xen.h>
 
 enum {