From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965391AbbJIAUQ (ORCPT ); Thu, 8 Oct 2015 20:20:16 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35427 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758977AbbJIARc (ORCPT ); Thu, 8 Oct 2015 20:17:32 -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, "Mark Rustad" , "Alexander Duyck" , "Bjorn Helgaas" Date: Fri, 09 Oct 2015 01:12:27 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 035/107] PCI: Add dev_flags bit to access VPD through function 0 In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.247 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.72-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Mark Rustad commit 932c435caba8a2ce473a91753bad0173269ef334 upstream. Add a dev_flags bit, PCI_DEV_FLAGS_VPD_REF_F0, to access VPD through function 0 to provide VPD access on other functions. This is for hardware devices that provide copies of the same VPD capability registers in multiple functions. Because the kernel expects that each function has its own registers, both the locking and the state tracking are affected by VPD accesses to different functions. On such devices for example, if a VPD write is performed on function 0, *any* later attempt to read VPD from any other function of that device will hang. This has to do with how the kernel tracks the expected value of the F bit per function. Concurrent accesses to different functions of the same device can not only hang but also corrupt both read and write VPD data. When hangs occur, typically the error message: vpd r/w failed. This is likely a firmware bug on this device. will be seen. Never set this bit on function 0 or there will be an infinite recursion. Signed-off-by: Mark Rustad Signed-off-by: Bjorn Helgaas Acked-by: Alexander Duyck Signed-off-by: Ben Hutchings --- drivers/pci/access.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++- include/linux/pci.h | 2 ++ 2 files changed, 62 insertions(+), 1 deletion(-) --- a/drivers/pci/access.c +++ b/drivers/pci/access.c @@ -355,6 +355,56 @@ static const struct pci_vpd_ops pci_vpd_ .release = pci_vpd_pci22_release, }; +static ssize_t pci_vpd_f0_read(struct pci_dev *dev, loff_t pos, size_t count, + void *arg) +{ + struct pci_dev *tdev = pci_get_slot(dev->bus, PCI_SLOT(dev->devfn)); + ssize_t ret; + + if (!tdev) + return -ENODEV; + + ret = pci_read_vpd(tdev, pos, count, arg); + pci_dev_put(tdev); + return ret; +} + +static ssize_t pci_vpd_f0_write(struct pci_dev *dev, loff_t pos, size_t count, + const void *arg) +{ + struct pci_dev *tdev = pci_get_slot(dev->bus, PCI_SLOT(dev->devfn)); + ssize_t ret; + + if (!tdev) + return -ENODEV; + + ret = pci_write_vpd(tdev, pos, count, arg); + pci_dev_put(tdev); + return ret; +} + +static const struct pci_vpd_ops pci_vpd_f0_ops = { + .read = pci_vpd_f0_read, + .write = pci_vpd_f0_write, + .release = pci_vpd_pci22_release, +}; + +static int pci_vpd_f0_dev_check(struct pci_dev *dev) +{ + struct pci_dev *tdev = pci_get_slot(dev->bus, PCI_SLOT(dev->devfn)); + int ret = 0; + + if (!tdev) + return -ENODEV; + if (!tdev->vpd || !tdev->multifunction || + dev->class != tdev->class || dev->vendor != tdev->vendor || + dev->device != tdev->device) + ret = -ENODEV; + + pci_dev_put(tdev); + return ret; +} + int pci_vpd_pci22_init(struct pci_dev *dev) { struct pci_vpd_pci22 *vpd; @@ -363,12 +413,21 @@ int pci_vpd_pci22_init(struct pci_dev *d cap = pci_find_capability(dev, PCI_CAP_ID_VPD); if (!cap) return -ENODEV; + if (dev->dev_flags & PCI_DEV_FLAGS_VPD_REF_F0) { + int ret = pci_vpd_f0_dev_check(dev); + + if (ret) + return ret; + } vpd = kzalloc(sizeof(*vpd), GFP_ATOMIC); if (!vpd) return -ENOMEM; vpd->base.len = PCI_VPD_PCI22_SIZE; - vpd->base.ops = &pci_vpd_pci22_ops; + if (dev->dev_flags & PCI_DEV_FLAGS_VPD_REF_F0) + vpd->base.ops = &pci_vpd_f0_ops; + else + vpd->base.ops = &pci_vpd_pci22_ops; mutex_init(&vpd->lock); vpd->cap = cap; vpd->busy = false; --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -176,6 +176,8 @@ enum pci_dev_flags { PCI_DEV_FLAGS_NO_D3 = (__force pci_dev_flags_t) 2, /* Provide indication device is assigned by a Virtual Machine Manager */ PCI_DEV_FLAGS_ASSIGNED = (__force pci_dev_flags_t) 4, + /* Get VPD from function 0 VPD */ + PCI_DEV_FLAGS_VPD_REF_F0 = (__force pci_dev_flags_t) (1 << 8), }; enum pci_irq_reroute_variant {