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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 EC8D2C47082 for ; Tue, 8 Jun 2021 06:49:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4F0C61246 for ; Tue, 8 Jun 2021 06:49:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230329AbhFHGvL (ORCPT ); Tue, 8 Jun 2021 02:51:11 -0400 Received: from regular1.263xmail.com ([211.150.70.206]:42976 "EHLO regular1.263xmail.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230281AbhFHGvJ (ORCPT ); Tue, 8 Jun 2021 02:51:09 -0400 Received: from localhost (unknown [192.168.167.32]) by regular1.263xmail.com (Postfix) with ESMTP id 92D1C1B43; Tue, 8 Jun 2021 14:48:47 +0800 (CST) X-MAIL-GRAY: 0 X-MAIL-DELIVERY: 1 X-ADDR-CHECKED4: 1 X-ANTISPAM-LEVEL: 2 X-SKE-CHECKED: 1 X-ABS-CHECKED: 1 Received: from [172.16.12.64] (unknown [58.22.7.114]) by smtp.263.net (postfix) whith ESMTP id P30809T139674015004416S1623134925256256_; Tue, 08 Jun 2021 14:48:46 +0800 (CST) X-IP-DOMAINF: 1 X-UNIQUE-TAG: X-RL-SENDER: shawn.lin@rock-chips.com X-SENDER: lintao@rock-chips.com X-LOGIN-NAME: shawn.lin@rock-chips.com X-FST-TO: javierm@redhat.com X-RCPT-COUNT: 11 X-SENDER-IP: 58.22.7.114 X-ATTACHMENT-NUM: 0 X-System-Flag: 0 Message-ID: Date: Tue, 8 Jun 2021 14:48:45 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:90.0) Gecko/20100101 Thunderbird/90.0 Cc: shawn.lin@rock-chips.com, Peter Robinson , Bjorn Helgaas , Heiko Stuebner , Lorenzo Pieralisi , Rob Herring , linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org Subject: =?UTF-8?Q?Re=3a_=5bPATCH=5d_PCI=3a_rockchip=3a_Avoid_accessing_PCIe?= =?UTF-8?B?IHJlZ2lzdGVycyB3aXRoIGNsb2NrcyBnYXRlZOOAkOivt+azqOaEj++8jOmCrg==?= =?UTF-8?Q?=e4=bb=b6=e7=94=b1linux-rockchip-bounces+shawn=2elin=3drock-chips?= =?UTF-8?B?LmNvbUBsaXN0cy5pbmZyYWRlYWQub3Jn5Luj5Y+R44CR?= To: Javier Martinez Canillas References: <20210607213328.1711570-1-javierm@redhat.com> From: Shawn Lin In-Reply-To: <20210607213328.1711570-1-javierm@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/6/8 5:33, Javier Martinez Canillas wrote: > IRQ handlers that are registered for shared interrupts can be called at > any time after have been registered using the request_irq() function. > > It's up to drivers to ensure that's always safe for these to be called. > > Both the "pcie-sys" and "pcie-client" interrupts are shared, but since > their handlers are registered very early in the probe function, an error > later can lead to these handlers being executed before all the required > have been properly setup. > > For example, the rockchip_pcie_read() function used by these IRQ handlers > expects that some PCIe clocks will already be enabled, otherwise trying > to access the PCIe registers causes the read to hang and never return. > > The CONFIG_DEBUG_SHIRQ option tests if drivers are able to cope with their > shared interrupt handlers being called, by generating a spurious interrupt > just before a shared interrupt handler is unregistered. > > But this means that if the option is enabled, any error in the probe path > of this driver could lead to one of the IRQ handlers to be executed. > > In a rockpro64 board, the following sequence of events happens: > > 1) "pcie-sys" IRQ is requested and its handler registered. > 2) "pcie-client" IRQ is requested and its handler registered. > 3) probe later fails due readl_poll_timeout() returning a timeout. > 4) the "pcie-sys" IRQ is unregistered. > 5) CONFIG_DEBUG_SHIRQ triggers a spurious interrupt. > 6) "pcie-client" IRQ handler is called for this spurious interrupt. > 7) IRQ handler tries to read PCIE_CLIENT_INT_STATUS with clocks gated. > 8) the machine hangs because rockchip_pcie_read() call never returns. > > To avoid cases like this, the handlers don't have to be registered until > very late in the probe function, once all the resources have been setup. > > So let's just move all the IRQ init before the pci_host_probe() call, that > will prevent issues like this and seems to be the correct thing to do too. > Acked-by: Shawn Lin Thanks. > Reported-by: Peter Robinson > Signed-off-by: Javier Martinez Canillas > --- > > drivers/pci/controller/pcie-rockchip-host.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/drivers/pci/controller/pcie-rockchip-host.c b/drivers/pci/controller/pcie-rockchip-host.c > index f1d08a1b159..78d04ac29cd 100644 > --- a/drivers/pci/controller/pcie-rockchip-host.c > +++ b/drivers/pci/controller/pcie-rockchip-host.c > @@ -592,10 +592,6 @@ static int rockchip_pcie_parse_host_dt(struct rockchip_pcie *rockchip) > if (err) > return err; > > - err = rockchip_pcie_setup_irq(rockchip); > - if (err) > - return err; > - > rockchip->vpcie12v = devm_regulator_get_optional(dev, "vpcie12v"); > if (IS_ERR(rockchip->vpcie12v)) { > if (PTR_ERR(rockchip->vpcie12v) != -ENODEV) > @@ -973,8 +969,6 @@ static int rockchip_pcie_probe(struct platform_device *pdev) > if (err) > goto err_vpcie; > > - rockchip_pcie_enable_interrupts(rockchip); > - > err = rockchip_pcie_init_irq_domain(rockchip); > if (err < 0) > goto err_deinit_port; > @@ -992,6 +986,12 @@ static int rockchip_pcie_probe(struct platform_device *pdev) > bridge->sysdata = rockchip; > bridge->ops = &rockchip_pcie_ops; > > + err = rockchip_pcie_setup_irq(rockchip); > + if (err) > + goto err_remove_irq_domain; > + > + rockchip_pcie_enable_interrupts(rockchip); > + > err = pci_host_probe(bridge); > if (err < 0) > goto err_remove_irq_domain; >