Richard Weinberger noticed that on some RTC hardware that
doesn't support UIE mode, due to coarse granular alarms
(like 1minute resolution), the current virtualized RTC
support doesn't properly error out when UIE is enabled.
Instead the current code queues an alarm for the next second,
but it won't fire until up to a miniute later.
This patch provides a generic way to flag this sort of hardware
and fixes the issue on the mpc5121 where Richard noticed the
problem.
CC: stable@vger.kernel.org
Reported-by: Richard Weinberger <richard@nod.at>
Tested-by: Richard Weinberger <richard@nod.at>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Currently, the RTC code does not disable the alarm in the hardware.
This means that after a sequence such as the one below (the files are in the
RTC sysfs), the box will boot up after 2 minutes even though we've
asked for the alarm to be turned off.
# echo $((`cat since_epoch`)+120) > wakealarm
# echo 0 > wakealarm
# poweroff
Fix this by disabling the alarm when there are no timers to run.
The original version of this patch was reverted. This version
disables the irq directly instead of setting a disabled timer
in the future.
Cc: stable@kernel.org
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
[Merged in the second revision from Rabin]
Signed-off-by: John Stultz <john.stultz@linaro.org>
If the alarm time programming in the rtc is ever in the past, it won't fire,
and any other alarm will be queued after it so they won't fire either.
So any time that the alarm might be in the past, we need to trigger
the irq handler to ensure the old alarm is cleared and the timer queue
is fully in the future.
This is done whenever the RTC clock is set.
This is the second revision of this patch, which was earlier reverted.
This version avoids the initialization problem, which is handled by
a different patch.
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: NeilBrown <neilb@suse.de>
[Remove problematic initialization change, update commit log, also
catch set_mmss case -jstultz]
Signed-off-by: John Stultz <john.stultz@linaro.org>
In some cases at boot up, the RTC alarm may be set in the past,
but still have the enabled flag on. This was causing problems,
because we would then enqueue the alarm into the timerqueue,
but it would never fire. This would clog up the timerqueue
and keep other alarms from working.
The fix is to check the alarm against the current rtc time at
boot and avoid enqueueing the alarm if it is in the past.
Reported-by: NeilBrown <neilb@suse.de>
Tested-by: NeilBrown <neilb@suse.de>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This reverts commit 93b2ec0128.
The call to "schedule_work()" in rtc_initialize_alarm() happens too
early, and can cause oopses at bootup
Neil Brown explains why we do it:
"If you set an alarm in the future, then shutdown and boot again after
that time, then you will end up with a timer_queue node which is in
the past.
When this happens the queue gets stuck. That entry-in-the-past won't
get removed until and interrupt happens and an interrupt won't happen
because the RTC only triggers an interrupt when the alarm is "now".
So you'll find that e.g. "hwclock" will always tell you that
'select' timed out.
So we force the interrupt work to happen at the start just in case."
and has a patch that convert it to do things in-process rather than with
the worker thread, but right now it's too late to play around with this,
so we just revert the patch that caused problems for now.
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Requested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Requested-by: John Stultz <john.stultz@linaro.org>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit c0afabd3d5.
It causes failures on Toshiba laptops - instead of disabling the alarm,
it actually seems to enable it on the affected laptops, resulting in
(for example) the laptop powering on automatically five minutes after
shutdown.
There's a patch for it that appears to work for at least some people,
but it's too late to play around with this, so revert for now and try
again in the next merge window.
See for example
http://bugs.debian.org/652869
Reported-and-bisected-by: Andreas Friedrich <afrie@gmx.net> (Toshiba Tecra)
Reported-by: Antonio-M. Corbi Bellot <antonio.corbi@ua.es> (Toshiba Portege R500)
Reported-by: Marco Santos <marco.santos@waynext.com> (Toshiba Portege Z830)
Reported-by: Christophe Vu-Brugier <cvubrugier@yahoo.fr> (Toshiba Portege R830)
Cc: Jonathan Nieder <jrnieder@gmail.com>
Requested-by: John Stultz <john.stultz@linaro.org>
Cc: stable@kernel.org # for the versions that applied this
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If the alarm time programming in the rtc is ever in the past, it won't fire,
and any other alarm will be queued after it so they won't fire either.
So any time that the alarm might be in the past, we need to trigger
the irq handler to ensure the old alarm is cleared and the timer queue
is fully in the future.
This can happen:
- when we first initialise the alarm
- when we set the time in the rtc.
so follow both of these by scheduling the timer work function.
CC: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
[Also catch set_mmss case -jstultz]
Signed-off-by: John Stultz <john.stultz@linaro.org>
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clockevents: Set noop handler in clockevents_exchange_device()
tick-broadcast: Stop active broadcast device when replacing it
clocksource: Fix bug with max_deferment margin calculation
rtc: Fix some bugs that allowed accumulating time drift in suspend/resume
rtc: Disable the alarm in the hardware
Currently, the RTC code does not disable the alarm in the hardware.
This means that after a sequence such as the one below (the files are in the
RTC sysfs), the box will boot up after 2 minutes even though we've
asked for the alarm to be turned off.
# echo $((`cat since_epoch`)+120) > wakealarm
# echo 0 > wakealarm
# poweroff
Fix this by disabling the alarm when there are no timers to run.
Cc: stable@kernel.org
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
The module.h was implicitly everywhere, but when we clean
that up, the implicit users will compile fail; fix them up
in advance.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Ben reported a lockup related to rtc. The lockup happens due to:
CPU0 CPU1
rtc_irq_set_state() __run_hrtimer()
spin_lock_irqsave(&rtc->irq_task_lock) rtc_handle_legacy_irq();
spin_lock(&rtc->irq_task_lock);
hrtimer_cancel()
while (callback_running);
So the running callback never finishes as it's blocked on
rtc->irq_task_lock.
Use hrtimer_try_to_cancel() instead and drop rtc->irq_task_lock while
waiting for the callback. Fix this for both rtc_irq_set_state() and
rtc_irq_set_freq().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Ben Greear <greearb@candelatech.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The RTC pie hrtimer is self rearming. We really need to limit the
frequency to something sensible. Thus limit it to the 8192Hz max
value from the rtc man documentation
Cc: Willy Tarreau <w@1wt.eu>
Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[jstultz: slightly reworked to use RTC_MAX_FREQ value]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Ben reported a lockup related to rtc. The lockup happens due to:
CPU0 CPU1
rtc_irq_set_state() __run_hrtimer()
spin_lock_irqsave(&rtc->irq_task_lock) rtc_handle_legacy_irq();
spin_lock(&rtc->irq_task_lock);
hrtimer_cancel()
while (callback_running);
So the running callback never finishes as it's blocked on
rtc->irq_task_lock.
Use hrtimer_try_to_cancel() instead and drop rtc->irq_task_lock while
waiting for the callback. Fix this for both rtc_irq_set_state() and
rtc_irq_set_freq().
Cc: stable@kernel.org
Reported-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
In rtc_irq_set_state, the code checks the correctness of the parameters,
but then goes on to unconditionally arms/disarms the hrtimer. Thus a
random task might arm/disarm rtc timer and surprise the real owner by
either generating events or by stopping them.
Cc: stable@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
It's not referenced outside this file so there's no need for it to be in
the global namespace and sparse warns about that.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
When we register an rtc device at boot, we read the alarm value
in hardware and set the rtc device's aie_timer to that value.
The initial method to do this was to simply call rtc_set_alarm()
with the value read from hardware. However, this may cause problems
as rtc_set_alarm may enable interupts, and the RTC alarm might fire,
which can cause invalid pointer dereferencing since the RTC registration
is not complete.
This patch solves the issue by initializing the rtc_device.aie_timer
y hand via rtc_initialize_alarm(). This avoids any calls to the RTC
hardware which might enable interrupts too early.
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Mark Brown pointed out a corner case: that RTC alarms should
be allowed to be persistent across reboots if the hardware
supported it.
The rework of the generic layer to virtualize the RTC alarm
virtualized much of the alarm handling, and removed the
code used to read the alarm time from the hardware.
Mark noted if we want the alarm to be persistent across
reboots, we need to re-read the alarm value into the
virtualized generic layer at boot up, so that the generic
layer properly exposes that value.
This patch restores much of the earlier removed
rtc_read_alarm code and wires it in so that we
set the kernel's alarm value to what we find in the
hardware at boot time.
NOTE: Not all hardware supports persistent RTC alarm state across
system reset. rtc-cmos for example will keep the alarm time, but
disables the AIE mode irq. Applications should not expect the RTC
alarm to be valid after a system reset. We will preserve what
we can, to represent the hardware state at boot, but its not
guarenteed.
Further, in the future, with multiplexed RTC alarms, the
soonest alarm to fire may not be the one set via the /dev/rt
ioctls. So an application may set the alarm with RTC_ALM_SET,
but after a reset find that RTC_ALM_READ returns an earlier
time. Again, we preserve what we can, but applications should
not expect the RTC alarm state to persist across a system reset.
Big thanks to Mark for pointing out the issue!
Thanks also to Marcelo for helping think through the solution.
CC: Mark Brown <broonie@opensource.wolfsonmicro.com>
CC: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: rtc-linux@googlegroups.com
Reported-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
On hardware that doesn't support alarm interrupts, rtc_alarm_irq_enable
could return without releasing the ops_lock mutex.
This was introduced in
aa0be0f (RTC: Propagate error handling via rtc_timer_enqueue properly)
This patch corrects the issue by only returning once the mutex is
released.
[john.stultz: Reworded the commit log]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This patch prevents a user space program from calling the RTC_IRQP_SET
ioctl with a negative value of frequency. Also, if this call is make
with a zero value of frequency, there would be a division by zero in the
kernel code.
[jstultz: Also initialize irq_freq to 1 to catch other divbyzero issues]
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br>
Signed-off-by: John Stultz <john.stultz@linaro.org>
