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Commit 1b783955 authored by Preeti U Murthy's avatar Preeti U Murthy Committed by Benjamin Herrenschmidt
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powerpc: Split timer_interrupt() into timer handling and interrupt handling routines 



Split timer_interrupt(), which is the local timer interrupt handler on ppc
into routines called during regular interrupt handling and __timer_interrupt(),
which takes care of running local timers and collecting time related stats.

This will enable callers interested only in running expired local timers to
directly call into __timer_interupt(). One of the use cases of this is the
tick broadcast IPI handling in which the sleeping CPUs need to handle the local
timers that have expired.

Signed-off-by: default avatarPreeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 1b67bee1

arch/powerpc/kernel/time.c

+46 −35
Original line number Diff line number Diff line
@@ -478,6 +478,47 @@ void arch_irq_work_raise(void) 


#endif /* CONFIG_IRQ_WORK */



void __timer_interrupt(void)

{

	struct pt_regs *regs = get_irq_regs();

	u64 *next_tb = &__get_cpu_var(decrementers_next_tb);

	struct clock_event_device *evt = &__get_cpu_var(decrementers);

	u64 now;



	trace_timer_interrupt_entry(regs);



	if (test_irq_work_pending()) {

		clear_irq_work_pending();

		irq_work_run();

	}



	now = get_tb_or_rtc();

	if (now >= *next_tb) {

		*next_tb = ~(u64)0;

		if (evt->event_handler)

			evt->event_handler(evt);

		__get_cpu_var(irq_stat).timer_irqs_event++;

	} else {

		now = *next_tb - now;

		if (now <= DECREMENTER_MAX)

			set_dec((int)now);

		/* We may have raced with new irq work */

		if (test_irq_work_pending())

			set_dec(1);

		__get_cpu_var(irq_stat).timer_irqs_others++;

	}



#ifdef CONFIG_PPC64

	/* collect purr register values often, for accurate calculations */

	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {

		struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);

		cu->current_tb = mfspr(SPRN_PURR);

	}

#endif



	trace_timer_interrupt_exit(regs);

}



/*

 * timer_interrupt - gets called when the decrementer overflows,

 * with interrupts disabled.
@@ -486,8 +527,6 @@ void timer_interrupt(struct pt_regs * regs) 
{

	struct pt_regs *old_regs;

	u64 *next_tb = &__get_cpu_var(decrementers_next_tb);

	struct clock_event_device *evt = &__get_cpu_var(decrementers);

	u64 now;



	/* Ensure a positive value is written to the decrementer, or else

	 * some CPUs will continue to take decrementer exceptions.
@@ -519,39 +558,7 @@ void timer_interrupt(struct pt_regs * regs) 
	old_regs = set_irq_regs(regs);

	irq_enter();



	trace_timer_interrupt_entry(regs);



	if (test_irq_work_pending()) {

		clear_irq_work_pending();

		irq_work_run();

	}



	now = get_tb_or_rtc();

	if (now >= *next_tb) {

		*next_tb = ~(u64)0;

		if (evt->event_handler)

			evt->event_handler(evt);

		__get_cpu_var(irq_stat).timer_irqs_event++;

	} else {

		now = *next_tb - now;

		if (now <= DECREMENTER_MAX)

			set_dec((int)now);

		/* We may have raced with new irq work */

		if (test_irq_work_pending())

			set_dec(1);

		__get_cpu_var(irq_stat).timer_irqs_others++;

	}



#ifdef CONFIG_PPC64

	/* collect purr register values often, for accurate calculations */

	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {

		struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);

		cu->current_tb = mfspr(SPRN_PURR);

	}

#endif



	trace_timer_interrupt_exit(regs);



	__timer_interrupt();

	irq_exit();

	set_irq_regs(old_regs);

}
@@ -828,6 +835,10 @@ static void decrementer_set_mode(enum clock_event_mode mode, 
/* Interrupt handler for the timer broadcast IPI */

void tick_broadcast_ipi_handler(void)

{

	u64 *next_tb = &__get_cpu_var(decrementers_next_tb);



	*next_tb = get_tb_or_rtc();

	__timer_interrupt();

}



static void register_decrementer_clockevent(int cpu)