diff --git a/arch/powerpc/include/asm/pci.h b/arch/powerpc/include/asm/pci.h
index 201e352d488d..6653f2743c4e 100644
--- a/arch/powerpc/include/asm/pci.h
+++ b/arch/powerpc/include/asm/pci.h
@@ -182,6 +182,7 @@ extern void pci_resource_to_user(const struct pci_dev *dev, int bar,
 				 const struct resource *rsrc,
 				 resource_size_t *start, resource_size_t *end);
 
+extern resource_size_t pcibios_io_space_offset(struct pci_controller *hose);
 extern void pcibios_setup_bus_devices(struct pci_bus *bus);
 extern void pcibios_setup_bus_self(struct pci_bus *bus);
 extern void pcibios_setup_phb_io_space(struct pci_controller *hose);
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 910b9dea7037..2efd52d714c2 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1492,6 +1492,11 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
 	return pci_enable_resources(dev, mask);
 }
 
+resource_size_t pcibios_io_space_offset(struct pci_controller *hose)
+{
+	return (unsigned long) hose->io_base_virt - _IO_BASE;
+}
+
 static void __devinit pcibios_setup_phb_resources(struct pci_controller *hose, struct list_head *resources)
 {
 	struct resource *res;
@@ -1516,8 +1521,7 @@ static void __devinit pcibios_setup_phb_resources(struct pci_controller *hose, s
 		 (unsigned long long)res->start,
 		 (unsigned long long)res->end,
 		 (unsigned long)res->flags);
-	pci_add_resource_offset(resources, res,
-			(resource_size_t) hose->io_base_virt - _IO_BASE);
+	pci_add_resource_offset(resources, res, pcibios_io_space_offset(hose));
 
 	/* Hookup PHB Memory resources */
 	for (i = 0; i < 3; ++i) {
diff --git a/arch/powerpc/kernel/pci_32.c b/arch/powerpc/kernel/pci_32.c
index fdd1a3d951dc..4b06ec5a502e 100644
--- a/arch/powerpc/kernel/pci_32.c
+++ b/arch/powerpc/kernel/pci_32.c
@@ -219,9 +219,9 @@ void __devinit pcibios_setup_phb_io_space(struct pci_controller *hose)
 	struct resource *res = &hose->io_resource;
 
 	/* Fixup IO space offset */
-	io_offset = (unsigned long)hose->io_base_virt - isa_io_base;
-	res->start = (res->start + io_offset) & 0xffffffffu;
-	res->end = (res->end + io_offset) & 0xffffffffu;
+	io_offset = pcibios_io_space_offset(hose);
+	res->start += io_offset;
+	res->end += io_offset;
 }
 
 static int __init pcibios_init(void)
diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
index 75417fdc773c..94a54f61d341 100644
--- a/arch/powerpc/kernel/pci_64.c
+++ b/arch/powerpc/kernel/pci_64.c
@@ -168,7 +168,7 @@ static int __devinit pcibios_map_phb_io_space(struct pci_controller *hose)
 		return -ENOMEM;
 
 	/* Fixup hose IO resource */
-	io_virt_offset = (unsigned long)hose->io_base_virt - _IO_BASE;
+	io_virt_offset = pcibios_io_space_offset(hose);
 	hose->io_resource.start += io_virt_offset;
 	hose->io_resource.end += io_virt_offset;