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authorDavid Woodhouse <dwmw@amazon.co.uk>2017-04-12 13:25:52 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-05-25 15:44:47 +0200
commit9ad81ecb28d611a07b59d8e899e0bd79a423aee2 (patch)
tree6f8b32d97361d06530e56efb1ba03ed17e32caa2 /drivers
parent6bec009a2f690c69239ab8c002aa1f5eca8c480e (diff)
PCI: Only allow WC mmap on prefetchable resources
commit cef4d02305a06be581bb7f4353446717a1b319ec upstream. The /proc/bus/pci mmap interface allows the user to specify whether they want WC or not. Don't let them do so on non-prefetchable BARs. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/pci/proc.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
index 78802ee42878..66c886365fbc 100644
--- a/drivers/pci/proc.c
+++ b/drivers/pci/proc.c
@@ -231,7 +231,7 @@ static int proc_bus_pci_mmap(struct file *file, struct vm_area_struct *vma)
{
struct pci_dev *dev = PDE_DATA(file_inode(file));
struct pci_filp_private *fpriv = file->private_data;
- int i, ret, write_combine, res_bit;
+ int i, ret, write_combine = 0, res_bit;
if (!capable(CAP_SYS_RAWIO))
return -EPERM;
@@ -251,10 +251,13 @@ static int proc_bus_pci_mmap(struct file *file, struct vm_area_struct *vma)
if (i >= PCI_ROM_RESOURCE)
return -ENODEV;
- if (fpriv->mmap_state == pci_mmap_mem)
- write_combine = fpriv->write_combine;
- else
- write_combine = 0;
+ if (fpriv->mmap_state == pci_mmap_mem &&
+ fpriv->write_combine) {
+ if (dev->resource[i].flags & IORESOURCE_PREFETCH)
+ write_combine = 1;
+ else
+ return -EINVAL;
+ }
ret = pci_mmap_page_range(dev, vma,
fpriv->mmap_state, write_combine);
if (ret < 0)