diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
index 8173e38..c8af6c5 100644
--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c
@@ -323,4 +323,12 @@
 }
 EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
 #endif
+
 #endif /* CONFIG_MEMORY_HOTPLUG */
+
+#ifdef CONFIG_PMB
+int __in_29bit_mode(void)
+{
+	return !(ctrl_inl(PMB_PASCR) & PASCR_SE);
+}
+#endif /* CONFIG_PMB */