diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 45fda71feb27465fcd4079744d0a19cd9f168ea9..0f11819d8f1dc07441f6e13362a4dca53f55fb87 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -560,7 +560,7 @@ subsys_initcall(add_system_ram_resources);
  */
 int devmem_is_allowed(unsigned long pfn)
 {
-	if (iomem_is_exclusive(pfn << PAGE_SHIFT))
+	if (iomem_is_exclusive(PFN_PHYS(pfn)))
 		return 0;
 	if (!page_is_ram(pfn))
 		return 1;