From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932678AbdCaGbw (ORCPT ); Fri, 31 Mar 2017 02:31:52 -0400 Received: from lelnx194.ext.ti.com ([198.47.27.80]:34010 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932545AbdCaGbt (ORCPT ); Fri, 31 Mar 2017 02:31:49 -0400 From: Keerthy To: , CC: , , , , , Subject: [PATCH] thermal: core: Add a back up thermal shutdown mechanism Date: Fri, 31 Mar 2017 12:00:20 +0530 Message-ID: <1490941820-13511-1-git-send-email-j-keerthy@ti.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org orderly_poweroff is triggered when a graceful shutdown of system is desired. This may be used in many critical states of the kernel such as when subsystems detects conditions such as critical temperature conditions. However, in certain conditions in system boot up sequences like those in the middle of driver probes being initiated, userspace will be unable to power off the system in a clean manner and leaves the system in a critical state. In cases like these, the /sbin/poweroff will return success (having forked off to attempt powering off the system. However, the system overall will fail to completely poweroff (since other modules will be probed) and the system is still functional with no userspace (since that would have shut itself off). However, there is no clean way of detecting such failure of userspace powering off the system. In such scenarios, it is necessary for a backup workqueue to be able to force a shutdown of the system when orderly shutdown is not successful after a configurable time period. Reported-by: Nishanth Menon Signed-off-by: Keerthy --- drivers/thermal/Kconfig | 13 +++++++++++++ drivers/thermal/thermal_core.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+) diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig index 0a16cf4..4cc55f9 100644 --- a/drivers/thermal/Kconfig +++ b/drivers/thermal/Kconfig @@ -15,6 +15,19 @@ menuconfig THERMAL if THERMAL +config THERMAL_EMERGENCY_POWEROFF_DELAY_MS + int "Emergency poweroff delay in milli-seconds" + depends on THERMAL + default 0 + help + The number of milliseconds to delay before emergency + poweroff kicks in. The delay should be carefully profiled + so as to give adequate time for orderly_poweroff. In case + of failure of an orderly_poweroff the emergency poweroff + kicks in after the delay has elapsed and shuts down the system. + + If set to 0 poweroff will happen immediately. + config THERMAL_HWMON bool prompt "Expose thermal sensors as hwmon device" diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c index 11f0675..dc7fdd4 100644 --- a/drivers/thermal/thermal_core.c +++ b/drivers/thermal/thermal_core.c @@ -322,6 +322,47 @@ static void handle_non_critical_trips(struct thermal_zone_device *tz, def_governor->throttle(tz, trip); } +/** + * emergency_poweroff_func - emergency poweroff work after a known delay + * @work: work_struct associated with the emergency poweroff function + * + * This function is called in very critical situations to force + * a kernel poweroff after a configurable timeout value. + */ +static void emergency_poweroff_func(struct work_struct *work) +{ + /** + * We have reached here after the emergency thermal shutdown + * Waiting period has expired. This means orderly_poweroff has + * not been able to shut off the system for some reason. + * Try to shut down the system immediately using pm_power_off + * if populated + */ + pr_warn("Attempting kernel_power_off\n"); + if (pm_power_off) + pm_power_off(); + + /** + * Worst of the worst case trigger emergency restart + */ + pr_warn("kernel_power_off has failed! Attempting emergency_restart\n"); + emergency_restart(); +} + +static DECLARE_DELAYED_WORK(emergency_poweroff_work, emergency_poweroff_func); + +/** + * emergency_poweroff - Trigger an emergency system poweroff + * + * This may be called from any critical situation to trigger a system shutdown + * after a known period of time. By default the delay is 0 millisecond + */ +void thermal_emergency_poweroff(void) +{ + schedule_delayed_work(&emergency_poweroff_work, + msecs_to_jiffies(CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS)); +} + static void handle_critical_trips(struct thermal_zone_device *tz, int trip, enum thermal_trip_type trip_type) { @@ -343,6 +384,7 @@ static void handle_critical_trips(struct thermal_zone_device *tz, "critical temperature reached(%d C),shutting down\n", tz->temperature / 1000); orderly_poweroff(true); + thermal_emergency_poweroff(); } } -- 1.9.1