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([2a01:e34:ed2f:f020:689d:e652:825c:501e]) by smtp.googlemail.com with ESMTPSA id y17sm13822381wrq.76.2021.04.16.22.32.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 16 Apr 2021 22:32:35 -0700 (PDT) Subject: Re: [PATCH v7 2/9] reboot: thermal: Export hardware protection shutdown To: Matti Vaittinen , Matti Vaittinen Cc: Mark Brown , Kees Cook , Andy Shevchenko , Zhang Rui , Guenter Roeck , "agross@kernel.org" , "devicetree@vger.kernel.org" , linux-power , "linux-kernel@vger.kernel.org" , "linux-renesas-soc@vger.kernel.org" , "linux-arm-msm@vger.kernel.org" , "bjorn.andersson@linaro.org" , "lgirdwood@gmail.com" , "robh+dt@kernel.org" , Amit Kucheria , Matteo Croce , Andrew Morton , Petr Mladek , "Rafael J. Wysocki" , Mike Rapoport , Josef Bacik , Kai-Heng Feng , linux-pm@vger.kernel.org References: From: Daniel Lezcano Message-ID: Date: Sat, 17 Apr 2021 07:32:33 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 14/04/2021 07:52, Matti Vaittinen wrote: > Thermal core contains a logic for safety shutdown. System is attempted to > be powered off if temperature exceeds safety limits. > > Currently this can be also utilized by regulator subsystem as a final > protection measure if PMICs report dangerous over-voltage, over-current or > over-temperature and if per regulator counter measures fail or do not > exist. > > Move this logic to kernel/reboot.c and export the functionality for other > subsystems to use. Also replace the mutex with a spinlock to allow using > the function from any context. > > Also the EMIF bus code has implemented a safety shut-down. EMIF does not > attempt orderly_poweroff at all. Thus the EMIF code is not converted to use > this new function. > > Signed-off-by: Matti Vaittinen > --- > Changelog > v7: > - new patch > > Please note - this patch has received only a minimal amount of testing. > (The new API call was tested to shut-down my system at driver probe but > no odd corner-cases have been tested). > > Any testing for thermal shutdown is appreciated. > --- > drivers/thermal/thermal_core.c | 63 ++----------------------- > include/linux/reboot.h | 1 + > kernel/reboot.c | 86 ++++++++++++++++++++++++++++++++++ Please send a patch implementing the reboot/shutdown and then another one replacing the thermal shutdown code by a call to the new API. > 3 files changed, 91 insertions(+), 59 deletions(-) > > diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c > index 996c038f83a4..b1444845af38 100644 > --- a/drivers/thermal/thermal_core.c > +++ b/drivers/thermal/thermal_core.c > @@ -36,10 +36,8 @@ static LIST_HEAD(thermal_governor_list); > > static DEFINE_MUTEX(thermal_list_lock); > static DEFINE_MUTEX(thermal_governor_lock); > -static DEFINE_MUTEX(poweroff_lock); > > static atomic_t in_suspend; > -static bool power_off_triggered; > > static struct thermal_governor *def_governor; > > @@ -327,70 +325,18 @@ static void handle_non_critical_trips(struct thermal_zone_device *tz, int trip) > def_governor->throttle(tz, trip); > } > > -/** > - * thermal_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 thermal_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 kernel_power_off > - * if populated > - */ > - WARN(1, "Attempting kernel_power_off: Temperature too high\n"); > - kernel_power_off(); > - > - /* > - * Worst of the worst case trigger emergency restart > - */ > - WARN(1, "Attempting emergency_restart: Temperature too high\n"); > - emergency_restart(); > -} > - > -static DECLARE_DELAYED_WORK(thermal_emergency_poweroff_work, > - thermal_emergency_poweroff_func); > - > -/** > - * thermal_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 this is not scheduled. > - */ > -static void thermal_emergency_poweroff(void) > +void thermal_zone_device_critical(struct thermal_zone_device *tz) > { > - int poweroff_delay_ms = CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS; > /* > * poweroff_delay_ms must be a carefully profiled positive value. > - * Its a must for thermal_emergency_poweroff_work to be scheduled > + * Its a must for forced_emergency_poweroff_work to be scheduled. > */ > - if (poweroff_delay_ms <= 0) > - return; > - schedule_delayed_work(&thermal_emergency_poweroff_work, > - msecs_to_jiffies(poweroff_delay_ms)); > -} > + int poweroff_delay_ms = CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS; > > -void thermal_zone_device_critical(struct thermal_zone_device *tz) > -{ > dev_emerg(&tz->device, "%s: critical temperature reached, " > "shutting down\n", tz->type); > > - mutex_lock(&poweroff_lock); > - if (!power_off_triggered) { > - /* > - * Queue a backup emergency shutdown in the event of > - * orderly_poweroff failure > - */ > - thermal_emergency_poweroff(); > - orderly_poweroff(true); > - power_off_triggered = true; > - } > - mutex_unlock(&poweroff_lock); > + hw_protection_shutdown("Temperature too high", poweroff_delay_ms); > } > EXPORT_SYMBOL(thermal_zone_device_critical); > > @@ -1549,7 +1495,6 @@ static int __init thermal_init(void) > ida_destroy(&thermal_cdev_ida); > mutex_destroy(&thermal_list_lock); > mutex_destroy(&thermal_governor_lock); > - mutex_destroy(&poweroff_lock); > return result; > } > postcore_initcall(thermal_init); > diff --git a/include/linux/reboot.h b/include/linux/reboot.h > index 3734cd8f38a8..af907a3d68d1 100644 > --- a/include/linux/reboot.h > +++ b/include/linux/reboot.h > @@ -79,6 +79,7 @@ extern char poweroff_cmd[POWEROFF_CMD_PATH_LEN]; > > extern void orderly_poweroff(bool force); > extern void orderly_reboot(void); > +void hw_protection_shutdown(const char *reason, int ms_until_forced); > > /* > * Emergency restart, callable from an interrupt handler. > diff --git a/kernel/reboot.c b/kernel/reboot.c > index a6ad5eb2fa73..1b5fa6d213d4 100644 > --- a/kernel/reboot.c > +++ b/kernel/reboot.c > @@ -518,6 +518,92 @@ void orderly_reboot(void) > } > EXPORT_SYMBOL_GPL(orderly_reboot); > > +/** > + * hw_failure_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 hw_failure_emergency_poweroff_func(struct work_struct *work) > +{ > + /* > + * We have reached here after the emergency 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 kernel_power_off > + * if populated > + */ > + WARN(1, "Hardware protection timed-out. Trying forced poweroff\n"); > + kernel_power_off(); > + > + /* > + * Worst of the worst case trigger emergency restart > + */ > + WARN(1, > + "Hardware protection shutdown failed. Trying emergency restart\n"); > + emergency_restart(); > +} > + > +static DECLARE_DELAYED_WORK(hw_failure_emergency_poweroff_work, > + hw_failure_emergency_poweroff_func); > + > +/** > + * hw_failure_emergency_poweroff - Trigger an emergency system poweroff > + * > + * This may be called from any critical situation to trigger a system shutdown > + * after a given period of time. If time is negative this is not scheduled. > + */ > +static void hw_failure_emergency_poweroff(int poweroff_delay_ms) > +{ > + if (poweroff_delay_ms <= 0) > + return; > + schedule_delayed_work(&hw_failure_emergency_poweroff_work, > + msecs_to_jiffies(poweroff_delay_ms)); > +} > + > +static bool prot_power_off_triggered; > +static DEFINE_SPINLOCK(poweroff_lock); > + > +/** > + * hw_protection_shutdown - Trigger an emergency system poweroff > + * > + * @reason: Reason of emergency shutdown to be printed. > + * @ms_until_forced: Time to wait for orderly shutdown before tiggering a > + * forced shudown. Negative value disables the forced > + * shutdown. > + * > + * Initiate an emergency system shutdown in order to protect hardware from > + * further damage. Usage examples include a thermal protection or a voltage or > + * current regulator failures. > + * NOTE: The request is ignored if protection shutdown is already pending even > + * if the previous request has given a large timeout for forced shutdown. > + * Can be called from any context. > + */ > +void hw_protection_shutdown(const char *reason, int ms_until_forced) > +{ > + unsigned long flags; > + > + pr_emerg("HARDWARE PROTECTION shutdown (%s)\n", reason); > + > + spin_lock_irqsave(&poweroff_lock, flags); > + if (prot_power_off_triggered) { > + spin_unlock(&poweroff_lock); Why not spin_unlock_irqrestore() ? > + return; > + } > + prot_power_off_triggered = true; > + spin_unlock_irqrestore(&poweroff_lock, flags); Why not take the spin_lock definitively for all the procedure ? eg. { ... pr_emerg( ... ); if (spin_trylock(&lock)) return; hw_failure_emergency_poweroff(ms_until_forced); orderly_poweroff(true); } No need of prot_power_off_triggered and the spin_lock can be declared static inside the function. > + /* > + * Queue a backup emergency shutdown in the event of > + * orderly_poweroff failure > + */ > + hw_failure_emergency_poweroff(ms_until_forced); > + orderly_poweroff(true); > +} > +EXPORT_SYMBOL_GPL(hw_protection_shutdown); > + > static int __init reboot_setup(char *str) > { > for (;;) { > -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog