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From cb4aa2ef6f748fa3a3e6cd3889153c191e63d48e Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Thu, 19 Jan 2012 15:20:58 +0000
Subject: [PATCH 28/49] 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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/arm/kernel/smp.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index e10e59a..1d1710e 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -471,9 +471,7 @@ 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
@@ -572,7 +570,9 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
switch (ipinr) {
case IPI_TIMER:
+ irq_enter();
ipi_timer();
+ irq_exit();
break;
case IPI_RESCHEDULE:
@@ -580,15 +580,21 @@ 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:
--
1.7.10
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