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=-11.3 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,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 E51ECC43461 for ; Mon, 14 Sep 2020 17:52:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A8F5520EDD for ; Mon, 14 Sep 2020 17:52:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726009AbgINL0u (ORCPT ); Mon, 14 Sep 2020 07:26:50 -0400 Received: from mail.loongson.cn ([114.242.206.163]:53026 "EHLO loongson.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726060AbgINLZ1 (ORCPT ); Mon, 14 Sep 2020 07:25:27 -0400 Received: from [10.130.0.80] (unknown [113.200.148.30]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9Dx38cFU19fCTIVAA--.5521S3; Mon, 14 Sep 2020 19:24:54 +0800 (CST) Subject: Re: [RFC PATCH v3] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices To: Huacai Chen References: <1600070215-3901-1-git-send-email-yangtiezhu@loongson.cn> <45a3e3a0-3dc6-e60e-9381-b436a7d6889a@loongson.cn> Cc: Bjorn Helgaas , linux-pci , linux-kernel , "Rafael J. Wysocki" , Konstantin Khlebnikov , Khalid Aziz , Vivek Goyal , Lukas Wunner , Oliver O'Halloran , Jiaxun Yang , Xuefeng Li , zhouyanjie , git , Huacai Chen From: Tiezhu Yang Message-ID: Date: Mon, 14 Sep 2020 19:24:53 +0800 User-Agent: Mozilla/5.0 (X11; Linux mips64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID: AQAAf9Dx38cFU19fCTIVAA--.5521S3 X-Coremail-Antispam: 1UD129KBjvJXoW3Xry3Wr4UKF1Dtw43Cr18uFg_yoWxJF4kpF ZxJanFyFW0qry2gr12qFyUXFyYqw1qy348Wry8G34fWrsFkryUtr47tF1aga4kXrZY9F17 J3s8t3yxuFyUJF7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUB014x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r1I6r4UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_Cr1j6rxdM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Cr0_Gr1UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvEwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lFIxGxcIEc7CjxVA2Y2ka 0xkIwI1lc7I2V7IY0VAS07AlzVAYIcxG8wCY02Avz4vE14v_Gw4l42xK82IYc2Ij64vIr4 1l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK 67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI 8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42xK8VAv wI8IcIk0rVWrZr1j6s0DMIIF0xvEx4A2jsIE14v26r4j6F4UMIIF0xvEx4A2jsIEc7CjxV AFwI0_Gr1j6F4UJbIYCTnIWIevJa73UjIFyTuYvjfUFDGYDUUUU X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On 09/14/2020 05:46 PM, Huacai Chen wrote: > Hi, Tiezhu, > > On Mon, Sep 14, 2020 at 5:30 PM Tiezhu Yang wrote: >> On 09/14/2020 04:52 PM, Huacai Chen wrote: >>> Hi, Tiezhu, >>> >>> How do you test kexec? kexec -e or systemctl kexec? Or both? >> kexec -l vmlinux --append="root=/dev/sda2 console=ttyS0,115200" >> kexec -e > So you haven't tested "systemctl kexec"? Yes, the distro I used is Loongnix which has not kexec service now. Is there any problem when use systemctl kexec? If you have more details, please let me know. > > Huacai >>> P.S., Please also CC my gmail (chenhuacai@gmail.com) since lemote.com >>> has some communication problems. >> OK, no problem. >> >>> Huacai >>> >>>> 陈华才江苏航天龙梦信息技术有限公司/研发中心/软件部 ------------------ Original ------------------From: "Tiezhu Yang";Date: Mon, Sep 14, 2020 03:57 PMTo: "Bjorn Helgaas"; Cc: "linux-pci"; "linux-kernel"; "Rafael J. Wysocki"; "Konstantin Khlebnikov"; "Khalid Aziz"; "Vivek Goyal"; "Lukas Wunner"; "Oliver O'Halloran"; "Huacai Chen"; "Jiaxun Yang"; "Xuefeng Li"; Subject: [RFC PATCH v3] PCI/portdrv: Only disable Bus Master on kexec reboot and connected PCI devices After commit 745be2e700cd ("PCIe: portdrv: call pci_disable_device >>>> during remove") and commit cc27b735ad3a ("PCI/portdrv: Turn off PCIe >>>> services during shutdown"), it also calls pci_disable_device() during >>>> shutdown, this leads to shutdown or reboot failure occasionally due to >>>> clear PCI_COMMAND_MASTER on the device in do_pci_disable_device(). >>>> >>>> drivers/pci/pci.c >>>> static void do_pci_disable_device(struct pci_dev *dev) >>>> { >>>> u16 pci_command; >>>> >>>> pci_read_config_word(dev, PCI_COMMAND, &pci_command); >>>> if (pci_command & PCI_COMMAND_MASTER) { >>>> pci_command &= ~PCI_COMMAND_MASTER; >>>> pci_write_config_word(dev, PCI_COMMAND, pci_command); >>>> } >>>> >>>> pcibios_disable_device(dev); >>>> } >>>> >>>> When remove "pci_command &= ~PCI_COMMAND_MASTER;", it can work well when >>>> shutdown or reboot. >>>> >>>> As Oliver O'Halloran said, no need to call pci_disable_device() when >>>> actually shutting down, but we should call pci_disable_device() before >>>> handing over to the new kernel on kexec reboot, so we can do some >>>> condition checks which are already executed afterwards by the function >>>> pci_device_shutdown(), this is done by commit 4fc9bbf98fd6 ("PCI: Disable >>>> Bus Master only on kexec reboot") and commit 6e0eda3c3898 ("PCI: Don't try >>>> to disable Bus Master on disconnected PCI devices"). >>>> >>>> drivers/pci/pci-driver.c >>>> static void pci_device_shutdown(struct device *dev) >>>> { >>>> ... >>>> if (drv && drv->shutdown) >>>> drv->shutdown(pci_dev); >>>> >>>> /* >>>> * If this is a kexec reboot, turn off Bus Master bit on the >>>> * device to tell it to not continue to do DMA. Don't touch >>>> * devices in D3cold or unknown states. >>>> * If it is not a kexec reboot, firmware will hit the PCI >>>> * devices with big hammer and stop their DMA any way. >>>> */ >>>> if (kexec_in_progress && (pci_dev->current_state <= PCI_D3hot)) >>>> pci_clear_master(pci_dev); >>>> } >>>> >>>> [ 36.159446] Call Trace: >>>> [ 36.241688] [] show_stack+0x9c/0x130 >>>> [ 36.326619] [] dump_stack+0xb0/0xf0 >>>> [ 36.410403] [] pcie_portdrv_shutdown+0x18/0x78 >>>> [ 36.495302] [] pci_device_shutdown+0x44/0x90 >>>> [ 36.580027] [] device_shutdown+0x130/0x290 >>>> [ 36.664486] [] kernel_power_off+0x38/0x80 >>>> [ 36.748272] [] __do_sys_reboot+0x1a4/0x258 >>>> [ 36.831985] [] syscall_common+0x34/0x58 >>>> >>>> Signed-off-by: Tiezhu Yang >>>> --- >>>> drivers/pci/pcie/portdrv_core.c | 1 - >>>> drivers/pci/pcie/portdrv_pci.c | 14 +++++++++++++- >>>> 2 files changed, 13 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c >>>> index 50a9522..1991aca 100644 >>>> --- a/drivers/pci/pcie/portdrv_core.c >>>> +++ b/drivers/pci/pcie/portdrv_core.c >>>> @@ -491,7 +491,6 @@ void pcie_port_device_remove(struct pci_dev *dev) >>>> { >>>> device_for_each_child(&dev->dev, NULL, remove_iter); >>>> pci_free_irq_vectors(dev); >>>> - pci_disable_device(dev); >>>> } >>>> >>>> /** >>>> diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c >>>> index 3a3ce40..cab37a8 100644 >>>> --- a/drivers/pci/pcie/portdrv_pci.c >>>> +++ b/drivers/pci/pcie/portdrv_pci.c >>>> @@ -143,6 +143,18 @@ static void pcie_portdrv_remove(struct pci_dev *dev) >>>> } >>>> >>>> pcie_port_device_remove(dev); >>>> + pci_disable_device(dev); >>>> +} >>>> + >>>> +static void pcie_portdrv_shutdown(struct pci_dev *dev) >>>> +{ >>>> + if (pci_bridge_d3_possible(dev)) { >>>> + pm_runtime_forbid(&dev->dev); >>>> + pm_runtime_get_noresume(&dev->dev); >>>> + pm_runtime_dont_use_autosuspend(&dev->dev); >>>> + } >>>> + >>>> + pcie_port_device_remove(dev); >>>> } >>>> >>>> static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev, >>>> @@ -211,7 +223,7 @@ static struct pci_driver pcie_portdriver = { >>>> >>>> .probe = pcie_portdrv_probe, >>>> .remove = pcie_portdrv_remove, >>>> - .shutdown = pcie_portdrv_remove, >>>> + .shutdown = pcie_portdrv_shutdown, >>>> >>>> .err_handler = &pcie_portdrv_err_handler, >>>> >>>> -- >>>> 2.1.0