Pull rework-memory-attribute-aliasing into release branch

1 files changed, 15 insertions, 2 deletions

diff --git a/arch/ia64/pci/pci.c b/arch/ia64/pci/pci.c
index ab829a22f8a4..30d148f34042 100644
--- a/arch/ia64/pci/pci.c
+++ b/arch/ia64/pci/pci.c
@@ -645,18 +645,31 @@ char *ia64_pci_get_legacy_mem(struct pci_bus *bus)
 int
 pci_mmap_legacy_page_range(struct pci_bus *bus, struct vm_area_struct *vma)
 {
+        unsigned long size = vma->vm_end - vma->vm_start;
+        pgprot_t prot;
         char *addr;
 
+        /*
+         * Avoid attribute aliasing.  See Documentation/ia64/aliasing.txt
+         * for more details.
+         */
+        if (!valid_mmap_phys_addr_range(vma->vm_pgoff << PAGE_SHIFT, size))
+                return -EINVAL;
+        prot = phys_mem_access_prot(NULL, vma->vm_pgoff, size,
+                                    vma->vm_page_prot);
+        if (pgprot_val(prot) != pgprot_val(pgprot_noncached(vma->vm_page_prot)))
+                return -EINVAL;
+
         addr = pci_get_legacy_mem(bus);
         if (IS_ERR(addr))
                 return PTR_ERR(addr);
 
         vma->vm_pgoff += (unsigned long)addr >> PAGE_SHIFT;
-        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+        vma->vm_page_prot = prot;
         vma->vm_flags |= (VM_SHM | VM_RESERVED | VM_IO);
 
         if (remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
-                            vma->vm_end - vma->vm_start, vma->vm_page_prot))
+                            size, vma->vm_page_prot))
                 return -EAGAIN;
 
         return 0;