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LoongArch: Implement constant timer shutdown interface 

When a cpu is hot-unplugged, it is put in idle state and the function
arch_cpu_idle_dead() is called. The timer interrupt for this processor
should be disabled, otherwise there will be pending timer interrupt for
the unplugged cpu, so that vcpu is prevented from giving up scheduling
when system is running in vm mode.

This patch implements the timer shutdown interface so that the constant
timer will be properly disabled when a CPU is hot-unplugged.

Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Bibo Mao 2023-11-21 15:03:25 +08:00 committed by Huacai Chen
parent 19d86a4962
commit d43f37b734
1 changed files with 11 additions and 16 deletions
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27
arch/loongarch/kernel/time.c
View File

@ -58,21 +58,6 @@ static int constant_set_state_oneshot(struct clock_event_device *evt)
return 0;
}
static int constant_set_state_oneshot_stopped(struct clock_event_device *evt)
{
unsigned long timer_config;
raw_spin_lock(&state_lock);
timer_config = csr_read64(LOONGARCH_CSR_TCFG);
timer_config &= ~CSR_TCFG_EN;
csr_write64(timer_config, LOONGARCH_CSR_TCFG);
raw_spin_unlock(&state_lock);
return 0;
}
static int constant_set_state_periodic(struct clock_event_device *evt)
{
unsigned long period;
@ -92,6 +77,16 @@ static int constant_set_state_periodic(struct clock_event_device *evt)
static int constant_set_state_shutdown(struct clock_event_device *evt)
{
unsigned long timer_config;
raw_spin_lock(&state_lock);
timer_config = csr_read64(LOONGARCH_CSR_TCFG);
timer_config &= ~CSR_TCFG_EN;
csr_write64(timer_config, LOONGARCH_CSR_TCFG);
raw_spin_unlock(&state_lock);
return 0;
}
@ -161,7 +156,7 @@ int constant_clockevent_init(void)
cd->rating = 320;
cd->cpumask = cpumask_of(cpu);
cd->set_state_oneshot = constant_set_state_oneshot;
cd->set_state_oneshot_stopped = constant_set_state_oneshot_stopped;
cd->set_state_oneshot_stopped = constant_set_state_shutdown;
cd->set_state_periodic = constant_set_state_periodic;
cd->set_state_shutdown = constant_set_state_shutdown;
cd->set_next_event = constant_timer_next_event;