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: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 46 insertions, 35 deletions

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 3ff97dbb35be..df2989b0d4c0 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -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)