diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 685406b..ff8f5b5 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -18,6 +18,15 @@
 	bool
 	select CPU_SH4
 
+config SH_32BIT
+	bool "32bit mode"
+	depends on CPU_SH4A
+	default n
+	help
+	  SH4A has 2 physical memory maps. This use 32bit mode.
+	  And this is board specific. Please check your board if you
+	  want to use this.
+
 choice
 	prompt "Target select"