From: David Woodhouse Date: Wed, 12 Apr 2017 12:25:52 +0000 (+0100) Subject: PCI: Only allow WC mmap on prefetchable resources X-Git-Tag: v3.2.92~31 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=999df205ec3140149a8eb56dfaefa0946e72327d;p=thirdparty%2Fkernel%2Fstable.git 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 Signed-off-by: Bjorn Helgaas Signed-off-by: Ben Hutchings --- diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c index d0319ddae9f4b..dab3219c80341 100644 --- a/drivers/pci/proc.c +++ b/drivers/pci/proc.c @@ -249,7 +249,7 @@ static int proc_bus_pci_mmap(struct file *file, struct vm_area_struct *vma) const struct proc_dir_entry *dp = PDE(inode); struct pci_dev *dev = dp->data; 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; @@ -269,10 +269,13 @@ 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)