From: Chang-An Chen <chang-an.chen@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Matthias Brugger <matthias.bgg@xxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Corey Minyard <cminyard@xxxxxxxxxx>
Cc: <linux-mediatek@xxxxxxxxxxxxxxxxxxx>
Cc: <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
Cc: <kuohong.wang@xxxxxxxxxxxx>
Cc: <freddy.hsin@xxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/1553828349-8914-1-git-send-email-chang-an.chen@xxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -272,7 +272,7 @@ 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];
@@ -283,7 +283,7 @@ 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
@@ -487,6 +487,7 @@ 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();
@@ -510,6 +511,7 @@ 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);
