From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9561C433DF for ; Wed, 26 Aug 2020 17:26:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AB2212080C for ; Wed, 26 Aug 2020 17:26:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726853AbgHZR0Q (ORCPT ); Wed, 26 Aug 2020 13:26:16 -0400 Received: from mga09.intel.com ([134.134.136.24]:36965 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726739AbgHZR0P (ORCPT ); Wed, 26 Aug 2020 13:26:15 -0400 IronPort-SDR: X03etxTlp38VB8MggvimCd20cyvhm+jpnjwEBnpjK3MxcSi0Wf6zthqsDWahhRu+HmgEIWMzrM QHuRMo7hWEvg== X-IronPort-AV: E=McAfee;i="6000,8403,9725"; a="157381172" X-IronPort-AV: E=Sophos;i="5.76,356,1592895600"; d="scan'208";a="157381172" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2020 10:26:13 -0700 IronPort-SDR: lYRRwx8zJRH1GF/6F102nz9em3jKRJKNDZG+lyn44hPGCnH7NMhT07s+o3KcU+FwwdBYDGVUb9 iphH3VAA8M8w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.76,356,1592895600"; d="scan'208";a="444126164" Received: from yliang6-mobl1.ccr.corp.intel.com (HELO [10.254.84.68]) ([10.254.84.68]) by orsmga004.jf.intel.com with ESMTP; 26 Aug 2020 10:26:12 -0700 Subject: Re: [PATCH v3 05/10] PCI/AER: Extend AER error handling to RCECs To: Sean V Kelley , bhelgaas@google.com, Jonathan.Cameron@huawei.com, rjw@rjwysocki.net, ashok.raj@intel.com, tony.luck@intel.com, qiuxu.zhuo@intel.com Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200812164659.1118946-1-sean.v.kelley@intel.com> <20200812164659.1118946-6-sean.v.kelley@intel.com> From: "Kuppuswamy, Sathyanarayanan" Message-ID: Date: Wed, 26 Aug 2020 10:26:12 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200812164659.1118946-6-sean.v.kelley@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On 8/12/20 9:46 AM, Sean V Kelley wrote: > From: Jonathan Cameron > > Currently the kernel does not handle AER errors for Root Complex > integrated End Points (RCiEPs)[0]. These devices sit on a root bus within > the Root Complex (RC). AER handling is performed by a Root Complex Event > Collector (RCEC) [1] which is a effectively a type of RCiEP on the same > root bus. > > For an RCEC (technically not a Bridge), error messages "received" from > associated RCiEPs must be enabled for "transmission" in order to cause a > System Error via the Root Control register or (when the Advanced Error > Reporting Capability is present) reporting via the Root Error Command > register and logging in the Root Error Status register and Error Source > Identification register. > > In addition to the defined OS level handling of the reset flow for the > associated RCiEPs of an RCEC, it is possible to also have non-native > handling. In that case there is no need to take any actions on the RCEC > because the firmware is responsible for them. This is true where APEI [2] > is used to report the AER errors via a GHES[v2] HEST entry [3] and > relevant AER CPER record [4] and non-native handling is in use. > > We effectively end up with two different types of discovery for > purposes of handling AER errors: > > 1) Normal bus walk - we pass the downstream port above a bus to which > the device is attached and it walks everything below that point. > > 2) An RCiEP with no visible association with an RCEC as there is no need > to walk devices. In that case, the flow is to just call the callbacks for > the actual device. > > A new walk function pci_walk_dev_affected(), similar to pci_bus_walk(), > is provided that takes a pci_dev instead of a bus. If that dev corresponds > to a downstream port it will walk the subordinate bus of that downstream > port. If the dev does not then it will call the function on that device > alone. > > [0] ACPI PCI Express Base Specification 5.0-1 1.3.2.3 Root Complex > Integrated Endpoint Rules. > [1] ACPI PCI Express Base Specification 5.0-1 6.2 Error Signalling and > Logging > [2] ACPI Specification 6.3 Chapter 18 ACPI Platform Error Interface (APEI) > [3] ACPI Specification 6.3 18.2.3.7 Generic Hardware Error Source > [4] UEFI Specification 2.8, N.2.7 PCI Express Error Section > > Signed-off-by: Jonathan Cameron > Signed-off-by: Sean V Kelley > --- > drivers/pci/pcie/err.c | 54 ++++++++++++++++++++++++++++++++++-------- > 1 file changed, 44 insertions(+), 10 deletions(-) > > diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c > index 14bb8f54723e..f4cfb37c26c1 100644 > --- a/drivers/pci/pcie/err.c > +++ b/drivers/pci/pcie/err.c > @@ -146,38 +146,68 @@ static int report_resume(struct pci_dev *dev, void *data) > return 0; > } > > +/** > + * pci_walk_dev_affected - walk devices potentially AER affected > + * @dev device which may be an RCEC with associated RCiEPs, > + * an RCiEP associated with an RCEC, or a Port. > + * @cb callback to be called for each device found > + * @userdata arbitrary pointer to be passed to callback. > + * > + * If the device provided is a bridge, walk the subordinate bus, > + * including any bridged devices on buses under this bus. > + * Call the provided callback on each device found. > + * > + * If the device provided has no subordinate bus, call the provided > + * callback on the device itself. > + */ > +static void pci_walk_dev_affected(struct pci_dev *dev, int (*cb)(struct pci_dev *, void *), > + void *userdata) > +{ > + if (dev->subordinate) > + pci_walk_bus(dev->subordinate, cb, userdata); > + else > + cb(dev, userdata); > +} > + > pci_ers_result_t pcie_do_recovery(struct pci_dev *dev, > enum pci_channel_state state, > pci_ers_result_t (*reset_link)(struct pci_dev *pdev)) > { > pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER; > - struct pci_bus *bus; > > /* > * Error recovery runs on all subordinates of the first downstream port. > * If the downstream port detected the error, it is cleared at the end. > + * For RCiEPs we should reset just the RCiEP itself. > */ > if (!(pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT || > - pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM)) > + pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM || > + pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END || > + pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC)) > dev = dev->bus->self; > - bus = dev->subordinate; > > pci_dbg(dev, "broadcast error_detected message\n"); > if (state == pci_channel_io_frozen) { > - pci_walk_bus(bus, report_frozen_detected, &status); > + pci_walk_dev_affected(dev, report_frozen_detected, &status); > + if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) { > + pci_warn(dev, "link reset not possible for RCiEP\n"); > + status = PCI_ERS_RESULT_NONE; > + goto failed; reset_link is not applicable for RC_END, but why do you want to fail it? > + } > + > status = reset_link(dev); > if (status != PCI_ERS_RESULT_RECOVERED) { > pci_warn(dev, "link reset failed\n"); > goto failed; > } > } else { > - pci_walk_bus(bus, report_normal_detected, &status); > + pci_walk_dev_affected(dev, report_normal_detected, &status); > } > > if (status == PCI_ERS_RESULT_CAN_RECOVER) { > status = PCI_ERS_RESULT_RECOVERED; > pci_dbg(dev, "broadcast mmio_enabled message\n"); > - pci_walk_bus(bus, report_mmio_enabled, &status); > + pci_walk_dev_affected(dev, report_mmio_enabled, &status); > } > > if (status == PCI_ERS_RESULT_NEED_RESET) { > @@ -188,17 +218,21 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev, > */ > status = PCI_ERS_RESULT_RECOVERED; > pci_dbg(dev, "broadcast slot_reset message\n"); > - pci_walk_bus(bus, report_slot_reset, &status); > + pci_walk_dev_affected(dev, report_slot_reset, &status); > } > > if (status != PCI_ERS_RESULT_RECOVERED) > goto failed; > > pci_dbg(dev, "broadcast resume message\n"); > - pci_walk_bus(bus, report_resume, &status); > + pci_walk_dev_affected(dev, report_resume, &status); > > - pci_aer_clear_device_status(dev); > - pci_aer_clear_nonfatal_status(dev); you want to prevent clearing status for RC_END ? Can you explain? > + if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT || > + pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM || > + pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC)) { > + pci_aer_clear_device_status(dev); > + pci_aer_clear_nonfatal_status(dev); > + } > pci_info(dev, "device recovery successful\n"); > return status; > > -- Sathyanarayanan Kuppuswamy Linux Kernel Developer