From patchwork Wed Nov 27 22:19:25 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Khalid Aziz X-Patchwork-Id: 294668 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 1CA812C007C for ; Thu, 28 Nov 2013 09:21:47 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757227Ab3K0WVh (ORCPT ); Wed, 27 Nov 2013 17:21:37 -0500 Received: from qmta01.emeryville.ca.mail.comcast.net ([76.96.30.16]:52371 "EHLO qmta01.emeryville.ca.mail.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757339Ab3K0WVf (ORCPT ); Wed, 27 Nov 2013 17:21:35 -0500 Received: from omta05.emeryville.ca.mail.comcast.net ([76.96.30.43]) by qmta01.emeryville.ca.mail.comcast.net with comcast id ulJ61m0050vp7WLA1mMbW6; Wed, 27 Nov 2013 22:21:35 +0000 Received: from mail.gonehiking.org ([50.134.149.16]) by omta05.emeryville.ca.mail.comcast.net with comcast id umKZ1m00C0MU7Qa8RmKZUe; Wed, 27 Nov 2013 22:19:34 +0000 Received: from concerto.us.oracle.com (concerto-wl.internal [192.168.1.22]) by mail.gonehiking.org (Postfix) with ESMTP id E155D8019F; Wed, 27 Nov 2013 15:19:40 -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 v2] PCI: Clear Bus Master bit only on kexec reboot Date: Wed, 27 Nov 2013 15:19:25 -0700 Message-Id: <1385590765-23094-1-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=1385590895; bh=geGFD5P4cB7p6de5m+u+UpcjnqFWJkK9yAgVH3vVHNU=; h=Received:Received:Received:From:To:Subject:Date:Message-Id; b=jJJq65QKhsXzxxZUnO4WNcvT7uB6qwBQ+bzX1dZ1v4x9+E05AaOrQnR/yHs1k/wHa i4Fw2uio6Pcm/UN00T4vx/2qOi9I16a4Z35RpAenbsu6iFiBmq07UOO++RDrSOXhG7 bTjAMSubaOitr+9N9Vn46FYuQYpakLFt76HA2+tIhcIIaA1yQqqg1CaMqzRxPRofSh 85xoyPLYyPtkGZZsuJYNlyAt58Qp+dHCl6IPHf90NBO1W4jeSjdyqKpuNES1N/Nkft 7T6mV6QwRBVajtPEIq8nFNOkfyijtgy10TnzLGKZbsZbv7XFfLNzZOlZC4Li85+50C XXMhoP1beLK+A== Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org 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 --- Changes since v1: - Moved kexec_in_progress flag from pci.h to kexec.h - Changed the type for kexec_in_progress flag to bool - Added #ifdef CONFIG_KEXEC to code in pci-driver.c to ensure it builds with CONFIG_KEXEC not set. drivers/pci/pci-driver.c | 12 +++++++++--- include/linux/kexec.h | 3 +++ kernel/kexec.c | 4 ++++ 3 files changed, 16 insertions(+), 3 deletions(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 9042fdb..8eca81a 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -19,6 +19,7 @@ #include #include #include +#include #include "pci.h" struct pci_dynid { @@ -399,12 +400,17 @@ static void pci_device_shutdown(struct device *dev) pci_msi_shutdown(pci_dev); pci_msix_shutdown(pci_dev); +#ifdef CONFIG_KEXEC /* - * 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); +#endif } #ifdef CONFIG_PM diff --git a/include/linux/kexec.h b/include/linux/kexec.h index d78d28a..5fd33dc 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -198,6 +198,9 @@ extern u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4]; extern size_t vmcoreinfo_size; extern size_t vmcoreinfo_max_size; +/* flag to track if kexec reboot is in progress */ +extern bool kexec_in_progress; + int __init parse_crashkernel(char *cmdline, unsigned long long system_ram, unsigned long long *crash_size, unsigned long long *crash_base); int parse_crashkernel_high(char *cmdline, unsigned long long system_ram, diff --git a/kernel/kexec.c b/kernel/kexec.c index 490afc0..d0d8fca 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 */ +bool kexec_in_progress = false; + /* 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 = true; kernel_restart_prepare(NULL); printk(KERN_EMERG "Starting new kernel\n"); machine_shutdown();