ARM: fix rcu stalls on SMP platforms

We can stall RCU processing on SMP platforms if a CPU sits in its idle
loop for a long time.  This happens because we don't call irq_enter()
and irq_exit() around generic_smp_call_function_interrupt() and
friends.  Add the necessary calls, and remove the one from within
ipi_timer(), so that they're all in a common place.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 57db122..26cdc49 100644 (file)
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -443,9 +443,7 @@ static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
 static void ipi_timer(void)
 {
        struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent);
-       irq_enter();
        evt->event_handler(evt);
-       irq_exit();
 }
 
 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
@@ -548,7 +546,9 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
 
        switch (ipinr) {
        case IPI_TIMER:
+               irq_enter();
                ipi_timer();
+               irq_exit();
                break;
 
        case IPI_RESCHEDULE:
@@ -556,15 +556,21 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
                break;
 
        case IPI_CALL_FUNC:
+               irq_enter();
                generic_smp_call_function_interrupt();
+               irq_exit();
                break;
 
        case IPI_CALL_FUNC_SINGLE:
+               irq_enter();
                generic_smp_call_function_single_interrupt();
+               irq_exit();
                break;
 
        case IPI_CPU_STOP:
+               irq_enter();
                ipi_cpu_stop(cpu);
+               irq_exit();
                break;
 
        default: