Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1648758 > unrolled thread

[PATCH 4.9 152/164] PCI: Only allow WC mmap on prefetchable resources

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  [PATCH 4.9 152/164] PCI: Only allow WC mmap on prefetchable resources Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-23 23:30 +0200

#1648758 — [PATCH 4.9 152/164] PCI: Only allow WC mmap on prefetchable resources

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Woodhouse <dwmw@amazon.co.uk>

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>

---
 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)

[toc] | [standalone]

Back to top | Article view | linux.kernel

csiph-web