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authorJisheng Zhang <jszhang@marvell.com>2015-10-20 16:02:34 +0800
committerDaniel Lezcano <daniel.lezcano@linaro.org>2015-10-27 01:32:33 +0100
commitd6df3576e6b4bcf765f5ace69915b4fa4a7ee1c3 (patch)
tree0ab04e90271ba7f74b0247bfaf93b5fb4f61330f /drivers/clocksource
parent56fd16cabac9cd8f15e2902898a9d0cc96e2fa70 (diff)
clocksource/drivers/arm_global_timer: Prevent ftrace recursion
Currently arm_global_timer can be used as a scheduler clock. We properly marked gt_sched_clock_read() as notrace but we then call another function gt_counter_read() that _wasn't_ notrace. Having a traceable function in the sched_clock() path leads to a recursion within ftrace and a kernel crash. Fix this by adding an extra notrace function to keep other users of gt_counter_read() traceable. Signed-off-by: Jisheng Zhang <jszhang@marvell.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Diffstat (limited to 'drivers/clocksource')
-rw-r--r--drivers/clocksource/arm_global_timer.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource/arm_global_timer.c
index 29ea50ac366a..a2cb6fae9295 100644
--- a/drivers/clocksource/arm_global_timer.c
+++ b/drivers/clocksource/arm_global_timer.c
@@ -60,7 +60,7 @@ static struct clock_event_device __percpu *gt_evt;
* different to the 32-bit upper value read previously, go back to step 2.
* Otherwise the 64-bit timer counter value is correct.
*/
-static u64 gt_counter_read(void)
+static u64 notrace _gt_counter_read(void)
{
u64 counter;
u32 lower;
@@ -79,6 +79,11 @@ static u64 gt_counter_read(void)
return counter;
}
+static u64 gt_counter_read(void)
+{
+ return _gt_counter_read();
+}
+
/**
* To ensure that updates to comparator value register do not set the
* Interrupt Status Register proceed as follows:
@@ -201,7 +206,7 @@ static struct clocksource gt_clocksource = {
#ifdef CONFIG_CLKSRC_ARM_GLOBAL_TIMER_SCHED_CLOCK
static u64 notrace gt_sched_clock_read(void)
{
- return gt_counter_read();
+ return _gt_counter_read();
}
#endif