diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c
index 62c5ea6d8682..8aa271b3d1ad 100644
--- a/arch/s390/pci/pci_mmio.c
+++ b/arch/s390/pci/pci_mmio.c
@@ -55,7 +55,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
 	ret = get_pfn(mmio_addr, VM_WRITE, &pfn);
 	if (ret)
 		goto out;
-	io_addr = (void *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
+	io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
 
 	ret = -EFAULT;
 	if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)
@@ -96,7 +96,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
 	ret = get_pfn(mmio_addr, VM_READ, &pfn);
 	if (ret)
 		goto out;
-	io_addr = (void *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
+	io_addr = (void __iomem *)((pfn << PAGE_SHIFT) | (mmio_addr & ~PAGE_MASK));
 
 	ret = -EFAULT;
 	if ((unsigned long) io_addr < ZPCI_IOMAP_ADDR_BASE)