This is a note to let you know that I've just added the patch titled
PCI: Only allow WC mmap on prefetchable resources
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
pci-only-allow-wc-mmap-on-prefetchable-resources.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From cef4d02305a06be581bb7f4353446717a1b319ec Mon Sep 17 00:00:00 2001
From: David Woodhouse <dwmw@xxxxxxxxxxxx>
Date: Wed, 12 Apr 2017 13:25:52 +0100
Subject: PCI: Only allow WC mmap on prefetchable resources
From: David Woodhouse <dwmw@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/pci/proc.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/drivers/pci/proc.c
+++ b/drivers/pci/proc.c
@@ -231,7 +231,7 @@ static int proc_bus_pci_mmap(struct file
{
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
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)
Patches currently in stable-queue which might be from dwmw@xxxxxxxxxxxx are
queue-4.9/pci-fix-another-sanity-check-bug-in-proc-pci-mmap.patch
queue-4.9/pci-only-allow-wc-mmap-on-prefetchable-resources.patch
queue-4.9/pci-fix-pci_mmap_fits-for-have_pci_resource_to_user-platforms.patch
queue-4.9/iommu-vt-d-flush-the-iotlb-to-get-rid-of-the-initial-kdump-mappings.patch