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authorStephen Boyd <sboyd@codeaurora.org>2013-04-17 16:26:18 -0700
committerOlof Johansson <olof@lixom.net>2013-04-26 17:17:29 -0700
commitf31c2f1c68aff83277eddc6798adf3438e9c680a (patch)
tree2019d040fe052e6979ebd211f12ec377da5f5c1e
parent405f5e5ee53339cf5d5d1753f8614938b1222562 (diff)
downloadvexpress-lsk-f31c2f1c68aff83277eddc6798adf3438e9c680a.tar.gz
ARM: arch_timer: Silence debug preempt warnings
Hot-plugging with CONFIG_DEBUG_PREEMPT=y on a device with arm architected timers causes a slew of "using smp_processor_id() in preemptible" warnings: BUG: using smp_processor_id() in preemptible [00000000] code: sh/111 caller is arch_timer_cpu_notify+0x14/0xc8 This happens because sometimes the cpu notifier, arch_timer_cpu_notify(), is called in preemptible context and other times in non-preemptible context but we use this_cpu_ptr() to retrieve the clockevent in all cases. We're only going to actually use the pointer in non-preemptible context though, so push the this_cpu_ptr() access down into the cases to force the checks to occur only in non-preemptible contexts. Cc: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mark Rutland <mark.rutland@arm.com> Acked-by: Marc Zyngier <Marc.Zyngier@arm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Olof Johansson <olof@lixom.net>
-rw-r--r--drivers/clocksource/arm_arch_timer.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 122ff05628b..a2b25418978 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -248,14 +248,16 @@ static void __cpuinit arch_timer_stop(struct clock_event_device *clk)
static int __cpuinit arch_timer_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
- struct clock_event_device *evt = this_cpu_ptr(arch_timer_evt);
-
+ /*
+ * Grab cpu pointer in each case to avoid spurious
+ * preemptible warnings
+ */
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_STARTING:
- arch_timer_setup(evt);
+ arch_timer_setup(this_cpu_ptr(arch_timer_evt));
break;
case CPU_DYING:
- arch_timer_stop(evt);
+ arch_timer_stop(this_cpu_ptr(arch_timer_evt));
break;
}