diff --git a/arch/sh/include/asm/io.h b/arch/sh/include/asm/io.h
index 0cf60a62881435559ddec1d1c930ba2d71298a5c..73a23f4617a37c5a5270d5bc50d9689af45d8f89 100644
--- a/arch/sh/include/asm/io.h
+++ b/arch/sh/include/asm/io.h
@@ -134,7 +134,7 @@ __BUILD_MEMORY_STRING(__raw_, q, u64)
  * load/store instructions. sh_io_port_base is the virtual address to
  * which all ports are being mapped.
  */
-extern const unsigned long sh_io_port_base;
+extern unsigned long sh_io_port_base;
 
 static inline void __set_io_port_base(unsigned long pbase)
 {
diff --git a/arch/sh/kernel/ioport.c b/arch/sh/kernel/ioport.c
index e3ad6103e7c181ba955b2c9967a41a8a61659eb7..cca14ba84a379fea07bb74ddaabb02bb062cd649 100644
--- a/arch/sh/kernel/ioport.c
+++ b/arch/sh/kernel/ioport.c
@@ -11,7 +11,7 @@
 #include <linux/module.h>
 #include <linux/io.h>
 
-const unsigned long sh_io_port_base __read_mostly = -1;
+unsigned long sh_io_port_base __read_mostly = -1;
 EXPORT_SYMBOL(sh_io_port_base);
 
 void __iomem *__ioport_map(unsigned long addr, unsigned int size)