diff --git a/arch/sh/include/asm/irq.h b/arch/sh/include/asm/irq.h
index 0f384b1f45ca..53fc18a3d4c2 100644
--- a/arch/sh/include/asm/irq.h
+++ b/arch/sh/include/asm/irq.h
@@ -13,12 +13,6 @@
  */
 #define NO_IRQ_IGNORE		((unsigned int)-1)
 
-/*
- * Simple Mask Register Support
- */
-extern void make_maskreg_irq(unsigned int irq);
-extern unsigned short *irq_mask_register;
-
 /*
  * PINT IRQs
  */
diff --git a/drivers/sh/intc/userimask.c b/drivers/sh/intc/userimask.c
index abe9091827cd..a363f77881d1 100644
--- a/drivers/sh/intc/userimask.c
+++ b/drivers/sh/intc/userimask.c
@@ -32,8 +32,11 @@ store_intc_userimask(struct device *dev,
 		     const char *buf, size_t count)
 {
 	unsigned long level;
+	int ret;
 
-	level = simple_strtoul(buf, NULL, 10);
+	ret = kstrtoul(buf, 10, &level);
+	if (ret != 0)
+		return ret;
 
 	/*
 	 * Minimal acceptable IRQ levels are in the 2 - 16 range, but