From: Chang-An Chen chang-an.chen@mediatek.com
commit 3f2552f7e9c5abef2775c53f7af66532f8bf65bc upstream.
tick_freeze() introduced by suspend-to-idle in commit 124cf9117c5f ("PM / sleep: Make it possible to quiesce timers during suspend-to-idle") uses timekeeping_suspend() instead of syscore_suspend() during suspend-to-idle. As a consequence generic sched_clock will keep going because sched_clock_suspend() and sched_clock_resume() are not invoked during suspend-to-idle which can result in a generic sched_clock wrap.
On a ARM system with suspend-to-idle enabled, sched_clock is registered as "56 bits at 13MHz, resolution 76ns, wraps every 4398046511101ns", which means the real wrapping duration is 8796093022202ns.
[ 134.551779] suspend-to-idle suspend (timekeeping_suspend()) [ 1204.912239] suspend-to-idle resume (timekeeping_resume()) ...... [ 1206.912239] suspend-to-idle suspend (timekeeping_suspend()) [ 5880.502807] suspend-to-idle resume (timekeeping_resume()) ...... [ 6000.403724] suspend-to-idle suspend (timekeeping_suspend()) [ 8035.753167] suspend-to-idle resume (timekeeping_resume()) ...... [ 8795.786684] (2)[321:charger_thread]...... [ 8795.788387] (2)[321:charger_thread]...... [ 0.057226] (0)[0:swapper/0]...... [ 0.061447] (2)[0:swapper/2]......
sched_clock was not stopped during suspend-to-idle, and sched_clock_poll hrtimer was not expired because timekeeping_suspend() was invoked during suspend-to-idle. It makes sched_clock wrap at kernel time 8796s.
To prevent this, invoke sched_clock_suspend() and sched_clock_resume() in tick_freeze() together with timekeeping_suspend() and timekeeping_resume().
Fixes: 124cf9117c5f (PM / sleep: Make it possible to quiesce timers during suspend-to-idle) Signed-off-by: Chang-An Chen chang-an.chen@mediatek.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: Frederic Weisbecker fweisbec@gmail.com Cc: Matthias Brugger matthias.bgg@gmail.com Cc: John Stultz john.stultz@linaro.org Cc: Kees Cook keescook@chromium.org Cc: Corey Minyard cminyard@mvista.com Cc: linux-mediatek@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Cc: Stanley Chu stanley.chu@mediatek.com Cc: kuohong.wang@mediatek.com Cc: freddy.hsin@mediatek.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/1553828349-8914-1-git-send-email-chang-an.chen@med... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/time/sched_clock.c | 4 ++-- kernel/time/tick-common.c | 2 ++ kernel/time/timekeeping.h | 7 +++++++ 3 files changed, 11 insertions(+), 2 deletions(-)
--- a/kernel/time/sched_clock.c +++ b/kernel/time/sched_clock.c @@ -275,7 +275,7 @@ static u64 notrace suspended_sched_clock return cd.read_data[seq & 1].epoch_cyc; }
-static int sched_clock_suspend(void) +int sched_clock_suspend(void) { struct clock_read_data *rd = &cd.read_data[0];
@@ -286,7 +286,7 @@ static int sched_clock_suspend(void) return 0; }
-static void sched_clock_resume(void) +void sched_clock_resume(void) { struct clock_read_data *rd = &cd.read_data[0];
--- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -491,6 +491,7 @@ void tick_freeze(void) trace_suspend_resume(TPS("timekeeping_freeze"), smp_processor_id(), true); system_state = SYSTEM_SUSPEND; + sched_clock_suspend(); timekeeping_suspend(); } else { tick_suspend_local(); @@ -514,6 +515,7 @@ void tick_unfreeze(void)
if (tick_freeze_depth == num_online_cpus()) { timekeeping_resume(); + sched_clock_resume(); system_state = SYSTEM_RUNNING; trace_suspend_resume(TPS("timekeeping_freeze"), smp_processor_id(), false); --- a/kernel/time/timekeeping.h +++ b/kernel/time/timekeeping.h @@ -14,6 +14,13 @@ extern u64 timekeeping_max_deferment(voi extern void timekeeping_warp_clock(void); extern int timekeeping_suspend(void); extern void timekeeping_resume(void); +#ifdef CONFIG_GENERIC_SCHED_CLOCK +extern int sched_clock_suspend(void); +extern void sched_clock_resume(void); +#else +static inline int sched_clock_suspend(void) { return 0; } +static inline void sched_clock_resume(void) { } +#endif
extern void do_timer(unsigned long ticks); extern void update_wall_time(void);