diff --git a/arch/ia64/kernel/machvec.c b/arch/ia64/kernel/machvec.c
index 1b604d02250b..ebd82535f51b 100644
--- a/arch/ia64/kernel/machvec.c
+++ b/arch/ia64/kernel/machvec.c
@@ -10,7 +10,9 @@
 
 #include <asm/page.h>
 
-struct ia64_machine_vector ia64_mv;
+struct ia64_machine_vector ia64_mv = {
+	.mmiowb	= ___ia64_mmiowb
+};
 EXPORT_SYMBOL(ia64_mv);
 
 static struct ia64_machine_vector * __init