ARM: fix rcu stalls on SMP platforms

commit 7deabca0acfe02b8e18f59a4c95676012f49a304 upstream.

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>
[add irq_enter()/irq_exit() in do_local_timer]
Signed-off-by: UCHINO Satoshi <satoshi.uchino@toshiba.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index fea97f64221..4469924d683 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -445,9 +445,7 @@ 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_LOCAL_TIMERS
@@ -458,7 +456,9 @@ asmlinkage void __exception_irq_entry do_local_timer(struct pt_regs *regs)
 
         if (local_timer_ack()) {
                 __inc_irq_stat(cpu, local_timer_irqs);
+                irq_enter();
                 ipi_timer();
+                irq_exit();
         }
 
         set_irq_regs(old_regs);
@@ -568,7 +568,9 @@ asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
 
         switch (ipinr) {
         case IPI_TIMER:
+                irq_enter();
                 ipi_timer();
+                irq_exit();
                 break;
 
         case IPI_RESCHEDULE:
@@ -576,15 +578,21 @@ asmlinkage void __exception_irq_entry do_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: