From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:54955 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752392AbdHRNO3 (ORCPT ); Fri, 18 Aug 2017 09:14:29 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "David Woodhouse" , "Bjorn Helgaas" Date: Fri, 18 Aug 2017 14:13:13 +0100 Message-ID: Subject: [PATCH 3.2 29/59] PCI: Only allow WC mmap on prefetchable resources In-Reply-To: Sender: stable-owner@vger.kernel.org List-ID: 3.2.92-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: David Woodhouse 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 --- drivers/pci/proc.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) --- a/drivers/pci/proc.c +++ b/drivers/pci/proc.c @@ -249,7 +249,7 @@ static int proc_bus_pci_mmap(struct file 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 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)