Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756649AbcDBAzb (ORCPT ); Fri, 1 Apr 2016 20:55:31 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:53995 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932241AbcDBAzX (ORCPT ); Fri, 1 Apr 2016 20:55:23 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Bjorn Helgaas , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 044/170] PCI: Disable IO/MEM decoding for devices with non-compliant BARs Date: Fri, 1 Apr 2016 17:52:10 -0700 Message-Id: <1459558456-24452-45-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1459558456-24452-1-git-send-email-kamal@canonical.com> References: <1459558456-24452-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2924 Lines: 84 3.19.8-ckt18 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ 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: Kamal Mostafa --- drivers/pci/probe.c | 14 ++++++++++++++ include/linux/pci.h | 1 + 2 files changed, 15 insertions(+) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index b7167ad..3efefa2 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -175,6 +175,9 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type, 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! */ @@ -1097,6 +1100,7 @@ int pci_cfg_space_size(struct pci_dev *dev) int pci_setup_device(struct pci_dev *dev) { u32 class; + u16 cmd; u8 hdr_type; struct pci_slot *slot; int pos = 0; @@ -1144,6 +1148,16 @@ 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) diff --git a/include/linux/pci.h b/include/linux/pci.h index 71e3f7f..fd5c01f 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -354,6 +354,7 @@ struct pci_dev { unsigned int broken_intx_masking:1; unsigned int io_window_1k:1; /* Intel P2P bridge 1K I/O windows */ unsigned int irq_managed: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 */ -- 2.7.4