From patchwork Wed Nov 27 19:18:28 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Khalid Aziz X-Patchwork-Id: 3249571 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: patchwork-linux-pci@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 06E7C9F474 for ; Wed, 27 Nov 2013 19:29:06 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D8142205F0 for ; Wed, 27 Nov 2013 19:29:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C7646205EE for ; Wed, 27 Nov 2013 19:29:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754857Ab3K0T2t (ORCPT ); Wed, 27 Nov 2013 14:28:49 -0500 Received: from qmta10.emeryville.ca.mail.comcast.net ([76.96.30.17]:60837 "EHLO qmta10.emeryville.ca.mail.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757187Ab3K0T2s (ORCPT ); Wed, 27 Nov 2013 14:28:48 -0500 Received: from omta15.emeryville.ca.mail.comcast.net ([76.96.30.71]) by qmta10.emeryville.ca.mail.comcast.net with comcast id uihD1m00A1Y3wxoAAjMiXD; Wed, 27 Nov 2013 19:21:42 +0000 Received: from mail.gonehiking.org ([50.134.149.16]) by omta15.emeryville.ca.mail.comcast.net with comcast id ujKf1m00s0MU7Qa8bjKgof; Wed, 27 Nov 2013 19:19:41 +0000 Received: from concerto.us.oracle.com (concerto-wl.internal [192.168.1.22]) by mail.gonehiking.org (Postfix) with ESMTP id 753EF80131; Wed, 27 Nov 2013 12:19:47 -0700 (MST) From: Khalid Aziz To: bhelgaas@google.com, cl91tp@gmail.com, tianyu.lan@intel.com, khlebnikov@openvz.org, gnomes@lxorguk.ukuu.org.uk, indou.takao@jp.fujitsu.com, jility09@gmail.com, f.otti@gmx.at, ebiederm@xmission.com, mjg59@srcf.ucam.org Cc: Khalid Aziz , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, stable@vger.kernel.org Subject: [PATCH] PCI: Clear Bus Master bit only on kexec reboot Date: Wed, 27 Nov 2013 12:18:28 -0700 Message-Id: <1385579908-24608-1-git-send-email-khalid.aziz@oracle.com> X-Mailer: git-send-email 1.8.3.2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20121106; t=1385580102; bh=P4DS4UVdyO1MHWzCBwNtgpWODIGPHYRMiMMnECTAEM0=; h=Received:Received:Received:From:To:Subject:Date:Message-Id; b=HTas7zdQ7w8dIPEfEU6b3vZ2+nQJDw2W0MRJ7uZQrHPom/Ud9w4wIPGDDgsRCFOFy 7W+e2CciGdEDSGa6ph0UFd/8tLxwMlXWKnSRdxbV3wXXCrfMOjZSDk7UW4nN3ZR/Ju n+tOr7Quq3WGz38DBY2saqZRBDydUkuhcj505xy89mRQPIJXKDUbHuA4lesepXBaLa uWgRiAUyiQwhxRuCbPKxRDZLn6KRIGyY+1EwUCkiozuGEFsT+alJlbOQZyQ9wdBOa8 aJ2RAVHV85Dzf8KNpC7kGqms6dEnK3F1oSH+MhwCbgBuQNu/VkUt5CkvAzVjd+rhcr BEpTMmzuhMb7Q== Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add a flag to tell the PCI subsystem that kernel is shutting down in prepapration to kexec a kernel. Add code in PCI subsystem to use this flag to clear Bus Master bit on PCI devices only in case of kexec reboot. This fixes https://bugzilla.kernel.org/show_bug.cgi?id=63861 and avoids any other issues caused by clearing Bus Master bit on PCI devices in normal shutdown path. This patch is based on discussion at http://marc.info/?l=linux-pci&m=138425645204355&w=2 Signed-off-by: Khalid Aziz Acked-by: Konstantin Khlebnikov Cc: stable@vger.kernel.org --- drivers/pci/pci-driver.c | 9 ++++++--- drivers/pci/pci.h | 3 +++ kernel/kexec.c | 4 ++++ 3 files changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 9042fdb..e920195 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -400,10 +400,13 @@ static void pci_device_shutdown(struct device *dev) pci_msix_shutdown(pci_dev); /* - * 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 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 (pci_dev->current_state <= PCI_D3hot) + if (kexec_in_progress && (pci_dev->current_state <= PCI_D3hot)) pci_clear_master(pci_dev); } diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 9c91ecc..7d85733 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -9,6 +9,9 @@ extern const unsigned char pcix_bus_speed[]; extern const unsigned char pcie_link_speed[]; +/* flag to track if kexec reboot is in progress */ +extern unsigned long kexec_in_progress; + /* Functions internal to the PCI core code */ int pci_create_sysfs_dev_files(struct pci_dev *pdev); diff --git a/kernel/kexec.c b/kernel/kexec.c index 490afc0..fd2d63e 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -47,6 +47,9 @@ u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4]; size_t vmcoreinfo_size; size_t vmcoreinfo_max_size = sizeof(vmcoreinfo_data); +/* Flag to indicate we are going to kexec a new kernel */ +unsigned long kexec_in_progress = 0; + /* Location of the reserved area for the crash kernel */ struct resource crashk_res = { .name = "Crash kernel", @@ -1675,6 +1678,7 @@ int kernel_kexec(void) } else #endif { + kexec_in_progress = 1; kernel_restart_prepare(NULL); printk(KERN_EMERG "Starting new kernel\n"); machine_shutdown();