x86, PAT, PCI: Change vma prot in pci_mmap to reflect inherited prot

upstream commit: 9cdec049389ce2c324fd1ec508a71528a27d4a07

While looking at the issue in the thread:

  http://marc.info/?l=dri-devel&m=123606627824556&w=2

noticed a bug in pci PAT code and memory type setting.

PCI mmap code did not set the proper protection in vma, when it
inherited protection in reserve_memtype. This bug only affects
the case where there exists a WC mapping before X does an mmap
with /proc or /sys pci interface. This will cause X userlevel
mmap from /proc or /sysfs to fail on fork.

Reported-by: Kevin Winchester <kjwinchester@gmail.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Dave Airlie <airlied@redhat.com>
LKML-Reference: <20090323190720.GA16831@linux-os.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index 844df0cbbd3e011784531ddb6e6ff1a06e7ec83c..d88c1b3b23012ca12ffeb40cd4670790759ac052 100644 (file)
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -329,6 +329,9 @@ int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
                        return -EINVAL;
                }
                flags = new_flags;
+               vma->vm_page_prot = __pgprot(
+                       (pgprot_val(vma->vm_page_prot) & ~_PAGE_CACHE_MASK) |
+                       flags);
        }
 
        if (((vma->vm_pgoff < max_low_pfn_mapped) ||