Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759802AbcDJTDf (ORCPT ); Sun, 10 Apr 2016 15:03:35 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:53187 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759356AbcDJS6z (ORCPT ); Sun, 10 Apr 2016 14:58:55 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bjorn Helgaas , Andi Kleen Subject: [PATCH 4.4 031/210] PCI: Disable IO/MEM decoding for devices with non-compliant BARs Date: Sun, 10 Apr 2016 11:34:12 -0700 Message-Id: <20160410183527.771607601@linuxfoundation.org> X-Mailer: git-send-email 2.8.0 In-Reply-To: <20160410183526.651820045@linuxfoundation.org> References: <20160410183526.651820045@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2682 Lines: 79 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bjorn Helgaas commit b84106b4e2290c081cdab521fa832596cdfea246 upstream. The PCI config header (first 64 bytes of each device's config space) is defined by the PCI spec so generic software can identify the device and manage its usage of I/O, memory, and IRQ resources. Some non-spec-compliant devices put registers other than BARs where the BARs should be. When the PCI core sizes these "BARs", the reads and writes it does may have unwanted side effects, and the "BAR" may appear to describe non-sensical address space. Add a flag bit to mark non-compliant devices so we don't touch their BARs. Turn off IO/MEM decoding to prevent the devices from consuming address space, since we can't read the BARs to find out what that address space would be. Signed-off-by: Bjorn Helgaas Tested-by: Andi Kleen Signed-off-by: Greg Kroah-Hartman --- drivers/pci/probe.c | 14 ++++++++++++++ include/linux/pci.h | 1 + 2 files changed, 15 insertions(+) --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -179,6 +179,9 @@ int __pci_read_base(struct pci_dev *dev, u16 orig_cmd; struct pci_bus_region region, inverted_region; + if (dev->non_compliant_bars) + return 0; + mask = type ? PCI_ROM_ADDRESS_MASK : ~0; /* No printks while decoding is disabled! */ @@ -1174,6 +1177,7 @@ void pci_msi_setup_pci_dev(struct pci_de int pci_setup_device(struct pci_dev *dev) { u32 class; + u16 cmd; u8 hdr_type; int pos = 0; struct pci_bus_region region; @@ -1219,6 +1223,16 @@ int pci_setup_device(struct pci_dev *dev /* device class may be changed after fixup */ class = dev->class >> 8; + if (dev->non_compliant_bars) { + pci_read_config_word(dev, PCI_COMMAND, &cmd); + if (cmd & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) { + dev_info(&dev->dev, "device has non-compliant BARs; disabling IO/MEM decoding\n"); + cmd &= ~PCI_COMMAND_IO; + cmd &= ~PCI_COMMAND_MEMORY; + pci_write_config_word(dev, PCI_COMMAND, cmd); + } + } + switch (dev->hdr_type) { /* header type */ case PCI_HEADER_TYPE_NORMAL: /* standard header */ if (class == PCI_CLASS_BRIDGE_PCI) --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -359,6 +359,7 @@ struct pci_dev { unsigned int io_window_1k:1; /* Intel P2P bridge 1K I/O windows */ unsigned int irq_managed:1; unsigned int has_secondary_link:1; + unsigned int non_compliant_bars:1; /* broken BARs; ignore them */ pci_dev_flags_t dev_flags; atomic_t enable_cnt; /* pci_enable_device has been called */