1 files changed, 17 insertions, 5 deletions

diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
index 73696b4a2eed..07d0e92742c8 100644
--- a/arch/ia64/pci/pci.c
+++ b/arch/ia64/pci/pci.c
@@ -591,6 +591,9 @@ int
 pci_mmap_page_range (struct pci_dev *dev, struct vm_area_struct *vma,
                      enum pci_mmap_state mmap_state, int write_combine)
 {
+        unsigned long size = vma->vm_end - vma->vm_start;
+        pgprot_t prot;
+
         /*
          * I/O space cannot be accessed via normal processor loads and
          * stores on this platform.
@@ -604,15 +607,24 @@ pci_mmap_page_range (struct pci_dev *dev, struct vm_area_struct *vma,
                  */
                 return -EINVAL;
 
+        if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
+                return -EINVAL;
+
+        prot = phys_mem_access_prot(NULL, vma->vm_pgoff, size,
+                                    vma->vm_page_prot);
+
         /*
-         * Leave vm_pgoff as-is, the PCI space address is the physical
-         * address on this platform.
+         * If the user requested WC, the kernel uses UC or WC for this region,
+         * and the chipset supports WC, we can use WC. Otherwise, we have to
+         * use the same attribute the kernel uses.
          */
-        if (write_combine && efi_range_is_wc(vma->vm_start,
-                                             vma->vm_end - vma->vm_start))
+        if (write_combine &&
+            ((pgprot_val(prot) & _PAGE_MA_MASK) == _PAGE_MA_UC ||
+             (pgprot_val(prot) & _PAGE_MA_MASK) == _PAGE_MA_WC) &&
+            efi_range_is_wc(vma->vm_start, vma->vm_end - vma->vm_start))
                 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
         else
-                vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+                vma->vm_page_prot = prot;
 
         if (remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
                              vma->vm_end - vma->vm_start, vma->vm_page_prot))