From f31c2f1c68aff83277eddc6798adf3438e9c680a Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Wed, 17 Apr 2013 16:26:18 -0700 Subject: [PATCH] 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 Cc: Thomas Gleixner Cc: Mark Rutland Acked-by: Marc Zyngier Signed-off-by: Stephen Boyd Signed-off-by: Olof Johansson --- drivers/clocksource/arm_arch_timer.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 122ff05628b5..a2b254189782 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; } -- 2.45.2