Commit 2a2d31c8 authored by Shaohua Li's avatar Shaohua Li Committed by Len Brown
Browse files

intel_idle: open broadcast clock event 



Intel_idle driver uses CLOCK_EVT_NOTIFY_BROADCAST_ENTER
CLOCK_EVT_NOTIFY_BROADCAST_EXIT
for broadcast clock events. The _ENTER/_EXIT doesn't really open broadcast clock
events, please see processor_idle.c for an example. In some situation, this will
cause boot hang, because some CPUs enters idle but local APIC timer stalls.

Reported-and-tested-by: default avatarYan Zheng <zheng.z.yan@intel.com>
Signed-off-by: default avatarShaohua Li <shaohua.li@intel.com>
cc: stable@kernel.org
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 53920837

drivers/idle/intel_idle.c

+46 −1
Original line number Diff line number Diff line
@@ -59,6 +59,8 @@ 
#include <linux/hrtimer.h>	/* ktime_get_real() */

#include <trace/events/power.h>

#include <linux/sched.h>

#include <linux/notifier.h>

#include <linux/cpu.h>

#include <asm/mwait.h>



#define INTEL_IDLE_VERSION "0.4"
@@ -73,6 +75,7 @@ static int max_cstate = MWAIT_MAX_NUM_CSTATES - 1; 


static unsigned int mwait_substates;



#define LAPIC_TIMER_ALWAYS_RELIABLE 0xFFFFFFFF

/* Reliable LAPIC Timer States, bit 1 for C1 etc.  */

static unsigned int lapic_timer_reliable_states = (1 << 1);	 /* Default to only C1 */
@@ -252,6 +255,39 @@ static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state) 
	return usec_delta;

}



static void __setup_broadcast_timer(void *arg)

{

	unsigned long reason = (unsigned long)arg;

	int cpu = smp_processor_id();



	reason = reason ?

		CLOCK_EVT_NOTIFY_BROADCAST_ON : CLOCK_EVT_NOTIFY_BROADCAST_OFF;



	clockevents_notify(reason, &cpu);

}



static int __cpuinit setup_broadcast_cpuhp_notify(struct notifier_block *n,

		unsigned long action, void *hcpu)

{

	int hotcpu = (unsigned long)hcpu;



	switch (action & 0xf) {

	case CPU_ONLINE:

		smp_call_function_single(hotcpu, __setup_broadcast_timer,

			(void *)true, 1);

		break;

	case CPU_DOWN_PREPARE:

		smp_call_function_single(hotcpu, __setup_broadcast_timer,

			(void *)false, 1);

		break;

	}

	return NOTIFY_OK;

}



static struct notifier_block __cpuinitdata setup_broadcast_notifier = {

	.notifier_call = setup_broadcast_cpuhp_notify,

};



/*

 * intel_idle_probe()

 */
@@ -314,7 +350,11 @@ static int intel_idle_probe(void) 
	}



	if (boot_cpu_has(X86_FEATURE_ARAT))	/* Always Reliable APIC Timer */

		lapic_timer_reliable_states = 0xFFFFFFFF;

		lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;

	else {

		smp_call_function(__setup_broadcast_timer, (void *)true, 1);

		register_cpu_notifier(&setup_broadcast_notifier);

	}



	pr_debug(PREFIX "v" INTEL_IDLE_VERSION

		" model 0x%X\n", boot_cpu_data.x86_model);
@@ -441,6 +481,11 @@ static void __exit intel_idle_exit(void) 
	intel_idle_cpuidle_devices_uninit();

	cpuidle_unregister_driver(&intel_idle_driver);



	if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE) {

		smp_call_function(__setup_broadcast_timer, (void *)false, 1);

		unregister_cpu_notifier(&setup_broadcast_notifier);

	}



	return;

}

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