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Commit 267538c2 authored by Olav Haugan's avatar Olav Haugan Committed by Satya Durga Srinivasu Prabhala
Browse files

watchdog: Add support for cpu isolation 



Open up interface to allow external subsystem to enable and disable hard
lockup detector.

Change-Id: I42b82e7c7869be1df0837c86d3d97aafb4b064bb
Signed-off-by: default avatarOlav Haugan <ohaugan@codeaurora.org>
[markivx: Forward port to 4.14 and moved sched.h diff to nmi.h]
Signed-off-by: default avatarVikram Mulukutla <markivx@codeaurora.org>
[satyap@codeaurora.org: Port to 4.19 and fix merge conflicts]
Signed-off-by: default avatarSatya Durga Srinivasu Prabhala <satyap@codeaurora.org>
parent 3832c3d3

drivers/base/core.c

+5 −0
Original line number Diff line number Diff line
@@ -716,6 +716,11 @@ int lock_device_hotplug_sysfs(void) 
	return restart_syscall();

}



void lock_device_hotplug_assert(void)

{

	lockdep_assert_held(&device_hotplug_lock);

}



#ifdef CONFIG_BLOCK

static inline int device_is_not_partition(struct device *dev)

{

include/linux/device.h

+1 −0
Original line number Diff line number Diff line
@@ -1203,6 +1203,7 @@ static inline bool device_supports_offline(struct device *dev) 
extern void lock_device_hotplug(void);

extern void unlock_device_hotplug(void);

extern int lock_device_hotplug_sysfs(void);

extern void lock_device_hotplug_assert(void);

extern int device_offline(struct device *dev);

extern int device_online(struct device *dev);

extern void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode);

include/linux/nmi.h

+17 −0
Original line number Diff line number Diff line
@@ -13,6 +13,9 @@ 


#ifdef CONFIG_LOCKUP_DETECTOR

void lockup_detector_init(void);

extern void watchdog_enable(unsigned int cpu);

extern void watchdog_disable(unsigned int cpu);

extern bool watchdog_configured(unsigned int cpu);

void lockup_detector_soft_poweroff(void);

void lockup_detector_cleanup(void);

bool is_hardlockup(void);
@@ -37,6 +40,20 @@ extern int sysctl_hardlockup_all_cpu_backtrace; 
static inline void lockup_detector_init(void) { }

static inline void lockup_detector_soft_poweroff(void) { }

static inline void lockup_detector_cleanup(void) { }

static inline void watchdog_enable(unsigned int cpu)

{

}

static inline void watchdog_disable(unsigned int cpu)

{

}

static inline bool watchdog_configured(unsigned int cpu)

{

	/*

	 * Pretend the watchdog is always configured.

	 * We will be waiting for the watchdog to be enabled in core isolation

	 */

	return true;

}

#endif /* !CONFIG_LOCKUP_DETECTOR */



#ifdef CONFIG_SOFTLOCKUP_DETECTOR

kernel/watchdog.c

+20 −2
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 


#include <linux/mm.h>

#include <linux/cpu.h>

#include <linux/device.h>

#include <linux/nmi.h>

#include <linux/init.h>

#include <linux/module.h>
@@ -170,6 +171,7 @@ static u64 __read_mostly sample_period; 


static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);

static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);

static DEFINE_PER_CPU(unsigned int, watchdog_en);

static DEFINE_PER_CPU(bool, softlockup_touch_sync);

static DEFINE_PER_CPU(bool, soft_watchdog_warn);

static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts);
@@ -469,16 +471,24 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer) 
	return HRTIMER_RESTART;

}



static void watchdog_enable(unsigned int cpu)

/* Must be called with hotplug lock (lock_device_hotplug()) held. */

void watchdog_enable(unsigned int cpu)

{

	struct hrtimer *hrtimer = this_cpu_ptr(&watchdog_hrtimer);

	struct completion *done = this_cpu_ptr(&softlockup_completion);

	unsigned int *enabled = this_cpu_ptr(&watchdog_en);



	WARN_ON_ONCE(cpu != smp_processor_id());



	init_completion(done);

	complete(done);



	lock_device_hotplug_assert();



	if (*enabled)

		return;

	*enabled = 1;



	/*

	 * Start the timer first to prevent the NMI watchdog triggering

	 * before the timer has a chance to fire.
@@ -495,9 +505,17 @@ static void watchdog_enable(unsigned int cpu) 
		watchdog_nmi_enable(cpu);

}



static void watchdog_disable(unsigned int cpu)

/* Must be called with hotplug lock (lock_device_hotplug()) held. */

void watchdog_disable(unsigned int cpu)

{

	struct hrtimer *hrtimer = this_cpu_ptr(&watchdog_hrtimer);

	unsigned int *enabled = this_cpu_ptr(&watchdog_en);



	lock_device_hotplug_assert();



	if (!*enabled)

		return;

	*enabled = 0;



	WARN_ON_ONCE(cpu != smp_processor_id());