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
......@@ -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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