From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756610AbbFPNrX (ORCPT ); Tue, 16 Jun 2015 09:47:23 -0400 Received: from mga09.intel.com ([134.134.136.24]:28833 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756218AbbFPNrP (ORCPT ); Tue, 16 Jun 2015 09:47:15 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,626,1427785200"; d="scan'208";a="744426324" From: Francois-Nicolas Muller To: linux@roeck-us.net Cc: wim@iguana.be, linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org, Francois-Nicolas Muller Subject: [PATCH v2] TCO watchdog pretimeout handler Date: Tue, 16 Jun 2015 15:45:14 +0200 Message-Id: <1434462314-17298-1-git-send-email-francois-nicolas.muller@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <20150615182941.GA19721@roeck-us.net> References: <20150615182941.GA19721@roeck-us.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use TCO watchdog first timeout (pretimeout) to dump CPU backtraces and ease debug of watchdog expiration causes. TCO logic generates a SCI interrupt, then its handler dumps all CPU backtraces and calls panic (in order to execute registered panic callbacks). SCI interrupt number (GPE) is configured from ACPI tables. Signed-off-by: Francois-Nicolas Muller --- Thanks Guenter for your review. > If I recall correctly, the iTCO watchdog can also generate an NMI. > Would it make sense to add support for handling this NMI as well ? As far as I know, there is no NMI option for TCO watchdog interrupt. Do you have any documentation about this ? Here is a new version (v2) of the patch: - rebased on latest kernel - fixed coding style issues Francois-Nicolas --- drivers/watchdog/iTCO_wdt.c | 50 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c index 3c3fd41..cd2569a 100644 --- a/drivers/watchdog/iTCO_wdt.c +++ b/drivers/watchdog/iTCO_wdt.c @@ -68,6 +68,8 @@ #include /* For inb/outb/... */ #include #include +#include +#include #include "iTCO_vendor.h" @@ -127,6 +129,12 @@ module_param(turn_SMI_watchdog_clear_off, int, 0); MODULE_PARM_DESC(turn_SMI_watchdog_clear_off, "Turn off SMI clearing watchdog (depends on TCO-version)(default=1)"); +#define DEFAULT_PRETIMEOUT 0 +static bool pretimeout = DEFAULT_PRETIMEOUT; +module_param(pretimeout, bool, 0); +MODULE_PARM_DESC(pretimeout, "Enable watchdog pretimeout (default=" + __MODULE_STRING(DEFAULT_PRETIMEOUT) ")"); + /* * Some TCO specific functions */ @@ -201,6 +209,45 @@ static int iTCO_wdt_unset_NO_REBOOT_bit(void) return ret; /* returns: 0 = OK, -EIO = Error */ } +static unsigned char *tco_hid = "8086229C"; + +static u32 iTCO_wdt_pretimeout_handler(acpi_handle gpe_device, u32 gpe, + void *context) +{ + /* dump backtraces for all available cores */ + trigger_all_cpu_backtrace(); + + /* call panic notifiers */ + panic("Kernel Watchdog"); + + return ACPI_INTERRUPT_HANDLED; +} + +static acpi_status __init iTCO_wdt_register_gpe(acpi_handle handle, + u32 lvl, void *context, void **rv) +{ + unsigned long long gpe; + acpi_status status; + union acpi_object object = { 0 }; + struct acpi_buffer buffer = { sizeof(union acpi_object), &object }; + + status = acpi_evaluate_object(handle, "_GPE", NULL, &buffer); + if (ACPI_FAILURE(status)) + return status; + + if (object.type != ACPI_TYPE_INTEGER) + return AE_BAD_DATA; + + gpe = object.integer.value; + status = acpi_install_gpe_handler(NULL, gpe, ACPI_GPE_EDGE_TRIGGERED, + iTCO_wdt_pretimeout_handler, NULL); + if (ACPI_FAILURE(status)) + return status; + + acpi_enable_gpe(NULL, gpe); + return AE_OK; +} + static int iTCO_wdt_start(struct watchdog_device *wd_dev) { unsigned int val; @@ -641,6 +688,9 @@ static int __init iTCO_wdt_init_module(void) if (err) return err; + if (pretimeout) + acpi_get_devices(tco_hid, iTCO_wdt_register_gpe, NULL, NULL); + return 0; } -- 1.9.1