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powerpc: Split timer_interrupt() into timer handling and interrupt handling routines

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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: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Preeti U Murthy 2014-02-26 05:38:01 +05:30 committed by Benjamin Herrenschmidt
parent 1b67bee129
commit 1b7839559b
1 changed files with 47 additions and 36 deletions
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83
arch/powerpc/kernel/time.c
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@ -478,47 +478,13 @@ void arch_irq_work_raise(void)
#endif /* CONFIG_IRQ_WORK */
/*
* timer_interrupt - gets called when the decrementer overflows,
* with interrupts disabled.
*/
void timer_interrupt(struct pt_regs * regs)
void __timer_interrupt(void)
{
struct pt_regs *old_regs;
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;
/* Ensure a positive value is written to the decrementer, or else
* some CPUs will continue to take decrementer exceptions.
*/
set_dec(DECREMENTER_MAX);
/* Some implementations of hotplug will get timer interrupts while
* offline, just ignore these and we also need to set
* decrementers_next_tb as MAX to make sure __check_irq_replay
* don't replay timer interrupt when return, otherwise we'll trap
* here infinitely :(
*/
if (!cpu_online(smp_processor_id())) {
*next_tb = ~(u64)0;
return;
}
/* Conditionally hard-enable interrupts now that the DEC has been
* bumped to its maximum value
*/
may_hard_irq_enable();
#if defined(CONFIG_PPC32) && defined(CONFIG_PMAC)
if (atomic_read(&ppc_n_lost_interrupts) != 0)
do_IRQ(regs);
#endif
old_regs = set_irq_regs(regs);
irq_enter();
trace_timer_interrupt_entry(regs);
if (test_irq_work_pending()) {
@ -551,7 +517,48 @@ void timer_interrupt(struct pt_regs * regs)
#endif
trace_timer_interrupt_exit(regs);
}
/*
* timer_interrupt - gets called when the decrementer overflows,
* with interrupts disabled.
*/
void timer_interrupt(struct pt_regs * regs)
{
struct pt_regs *old_regs;
u64 *next_tb = &__get_cpu_var(decrementers_next_tb);
/* Ensure a positive value is written to the decrementer, or else
* some CPUs will continue to take decrementer exceptions.
*/
set_dec(DECREMENTER_MAX);
/* Some implementations of hotplug will get timer interrupts while
* offline, just ignore these and we also need to set
* decrementers_next_tb as MAX to make sure __check_irq_replay
* don't replay timer interrupt when return, otherwise we'll trap
* here infinitely :(
*/
if (!cpu_online(smp_processor_id())) {
*next_tb = ~(u64)0;
return;
}
/* Conditionally hard-enable interrupts now that the DEC has been
* bumped to its maximum value
*/
may_hard_irq_enable();
#if defined(CONFIG_PPC32) && defined(CONFIG_PMAC)
if (atomic_read(&ppc_n_lost_interrupts) != 0)
do_IRQ(regs);
#endif
old_regs = set_irq_regs(regs);
irq_enter();
__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)