diff --git a/arch/alpha/include/asm/io.h b/arch/alpha/include/asm/io.h
index 0fab5ac90775827345e7c0522a27bf6fd440b184..c9cb554fbe54ced5d8dd27e6b3430f37f71c9b34 100644
--- a/arch/alpha/include/asm/io.h
+++ b/arch/alpha/include/asm/io.h
@@ -60,7 +60,7 @@ extern inline void set_hae(unsigned long new_hae)
  * Change virtual addresses to physical addresses and vv.
  */
 #ifdef USE_48_BIT_KSEG
-static inline unsigned long virt_to_phys(void *address)
+static inline unsigned long virt_to_phys(volatile void *address)
 {
 	return (unsigned long)address - IDENT_ADDR;
 }
@@ -70,7 +70,7 @@ static inline void * phys_to_virt(unsigned long address)
 	return (void *) (address + IDENT_ADDR);
 }
 #else
-static inline unsigned long virt_to_phys(void *address)
+static inline unsigned long virt_to_phys(volatile void *address)
 {
         unsigned long phys = (unsigned long)address;
 
@@ -106,7 +106,7 @@ static inline void * phys_to_virt(unsigned long address)
 extern unsigned long __direct_map_base;
 extern unsigned long __direct_map_size;
 
-static inline unsigned long __deprecated virt_to_bus(void *address)
+static inline unsigned long __deprecated virt_to_bus(volatile void *address)
 {
 	unsigned long phys = virt_to_phys(address);
 	unsigned long bus = phys + __direct_map_base;