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Tight loops of spin_lock_irqsave() and spin_unlock_irqrestore()
in timer and hrtimer are causing scheduling delays. Add delay of
few nano seconds after cpu_relax in the timer/hrtimer tight loops.
Change-Id: Iaa0ab92da93f7b245b1d922b6edca2bebdc0fbce
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
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Fix backport of commit f18ddc13af981ce3c7b7f26925f099e7c6929aba upstream.
Update backport to change ENOTSUPP to EOPNOTSUPP in
alarm_timer_{del,set}(), which were removed in
f2c45807d3992fe0f173f34af9c347d907c31686 in v4.13-rc1.
Fixes: c22df8ea7c5831d6fdca2f6f136f0d32d7064ff9
Signed-off-by: Petr Vorel <pvorel@suse.cz>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f18ddc13af981ce3c7b7f26925f099e7c6929aba upstream.
ENOTSUPP is not supposed to be returned to userspace. This was found on an
OpenPower machine, where the RTC does not support set_alarm.
On that system, a clock_nanosleep(CLOCK_REALTIME_ALARM, ...) results in
"524 Unknown error 524"
Replace it with EOPNOTSUPP which results in the expected "95 Operation not
supported" error.
Fixes: 1c6b39ad3f01 (alarmtimers: Return -ENOTSUPP if no RTC device is present)
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190903171802.28314-1-cascardo@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This reverts commit 2e1a4aefef66db901f9a906b79e30187f10dbecb.
Power off alarm is not set via alarmtimer now. Remove the changes
of power off alarm's previous design.
Change-Id: I0f60bec0d94c93c4f2a89ae86a1b0a0d04aa9e48
Signed-off-by: Mao Jinlong <jinlmao@codeaurora.org>
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[ Upstream commit 5f936e19cc0ef97dbe3a56e9498922ad5ba1edef ]
Air Icy reported:
UBSAN: Undefined behaviour in kernel/time/alarmtimer.c:811:7
signed integer overflow:
1529859276030040771 + 9223372036854775807 cannot be represented in type 'long long int'
Call Trace:
alarm_timer_nsleep+0x44c/0x510 kernel/time/alarmtimer.c:811
__do_sys_clock_nanosleep kernel/time/posix-timers.c:1235 [inline]
__se_sys_clock_nanosleep kernel/time/posix-timers.c:1213 [inline]
__x64_sys_clock_nanosleep+0x326/0x4e0 kernel/time/posix-timers.c:1213
do_syscall_64+0xb8/0x3a0 arch/x86/entry/common.c:290
alarm_timer_nsleep() uses ktime_add() to add the current time and the
relative expiry value. ktime_add() has no sanity checks so the addition
can overflow when the relative timeout is large enough.
Use ktime_add_safe() which has the necessary sanity checks in place and
limits the result to the valid range.
Fixes: 9a7adcf5c6de ("timers: Posix interface for alarm-timers")
Reported-by: Team OWL337 <icytxw@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1807020926360.1595@nanos.tec.linutronix.de
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit ff86bf0c65f1 ("alarmtimer: Rate limit periodic intervals") sets a
minimum bound on the alarm timer interval. This minimum bound shouldn't
be applied if the interval is 0. Otherwise, one-shot timers will be
converted into periodic ones.
Fixes: ff86bf0c65f1 ("alarmtimer: Rate limit periodic intervals")
Reported-by: Ben Fennema <fennema@google.com>
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Cc: stable@vger.kernel.org
Cc: John Stultz <john.stultz@linaro.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ff86bf0c65f14346bf2440534f9ba5ac232c39a0 upstream.
The alarmtimer code has another source of potentially rearming itself too
fast. Interval timers with a very samll interval have a similar CPU hog
effect as the previously fixed overflow issue.
The reason is that alarmtimers do not implement the normal protection
against this kind of problem which the other posix timer use:
timer expires -> queue signal -> deliver signal -> rearm timer
This scheme brings the rearming under scheduler control and prevents
permanently firing timers which hog the CPU.
Bringing this scheme to the alarm timer code is a major overhaul because it
lacks all the necessary mechanisms completely.
So for a quick fix limit the interval to one jiffie. This is not
problematic in practice as alarmtimers are usually backed by an RTC for
suspend which have 1 second resolution. It could be therefor argued that
the resolution of this clock should be set to 1 second in general, but
that's outside the scope of this fix.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kostya Serebryany <kcc@google.com>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Link: http://lkml.kernel.org/r/20170530211655.896767100@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f4781e76f90df7aec400635d73ea4c35ee1d4765 upstream.
Andrey reported a alartimer related RCU stall while fuzzing the kernel with
syzkaller.
The reason for this is an overflow in ktime_add() which brings the
resulting time into negative space and causes immediate expiry of the
timer. The following rearm with a small interval does not bring the timer
back into positive space due to the same issue.
This results in a permanent firing alarmtimer which hogs the CPU.
Use ktime_add_safe() instead which detects the overflow and clamps the
result to KTIME_SEC_MAX.
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kostya Serebryany <kcc@google.com>
Cc: syzkaller <syzkaller@googlegroups.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Link: http://lkml.kernel.org/r/20170530211655.802921648@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Currently, mpm wakeup time is programmed in seconds
due to which there is a possibility that wakeup
happens later than the expected time. This patch
fixes the issue by programming the mpm wakeup time
in milliseconds.
CRs-Fixed: 2010001
Change-Id: I5c4905a0386e60ae54876f30d89f445fd06a161c
Signed-off-by: Mohit Aggarwal <maggarwa@codeaurora.org>
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lpm-level headers required only when CONFIG_MSM_PM is set.
To compile msm kernel for other targets (arch=um), add config
check to include lpm levels.
Change-Id: Ia1bd51da4952e56b945a5e51a3b1ff8aaa643cd5
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>
Signed-off-by: Jeevan Shriram <jshriram@codeaurora.org>
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Currently, RTC_ALARM is used to wake-up target from
suspend state and is also used for power-off alarm
feature. This patch uses qtimer to wake-up from
suspend state.
Change-Id: Ia42cfecd573309be2f03c18b4f1c321be8202d7d
Signed-off-by: Mohit Aggarwal <maggarwa@codeaurora.org>
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Android does not support powering-up the phone through alarm.
Set rtc alarm in timerfd to power-up the phone after alarm
expiration.
Change-Id: I781389c658fb00ba7f0ce089d706c10f202a7dc6
Signed-off-by: Mao Jinlong <c_jmao@codeaurora.org>
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Add the rtc irq support for alarmtimer to wakeup the
alarm during system suspend.
Change-Id: I41b774ed4e788359321e1c6a564551cc9cd40c8e
Signed-off-by: Xiaocheng Li <lix@codeaurora.org>
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We want to get rid of the hrtimer_start() return value and the alarm
timer return value is nowhere used. Remove it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20150414203503.243910615@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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The resolution is directly accessible now. So its simpler just to fill
in the values of the timespec and be done with it.
Text size reduction (combined with "hrtimer: Get rid of the resolution
field in hrtimer_clock_base"):
x8664 -61, i386 -221, ARM -60, power64 -48
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20150414203500.879888080@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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If an attacker can cause a controlled kernel stack overflow, overwriting
the restart block is a very juicy exploit target. This is because the
restart_block is held in the same memory allocation as the kernel stack.
Moving the restart block to struct task_struct prevents this exploit by
making the restart_block harder to locate.
Note that there are other fields in thread_info that are also easy
targets, at least on some architectures.
It's also a decent simplification, since the restart code is more or less
identical on all architectures.
[james.hogan@imgtec.com: metag: align thread_info::supervisor_stack]
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Miller <davem@davemloft.net>
Acked-by: Richard Weinberger <richard@nod.at>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Locks the k_itimer's it_lock member when handling the alarm timer's
expiry callback.
The regular posix timers defined in posix-timers.c have this lock held
during timout processing because their callbacks are routed through
posix_timer_fn(). The alarm timers follow a different path, so they
ought to grab the lock somewhere else.
Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: Richard Larocque <rlarocque@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Avoids sending a signal to alarm timers created with sigev_notify set to
SIGEV_NONE by checking for that special case in the timeout callback.
The regular posix timers avoid sending signals to SIGEV_NONE timers by
not scheduling any callbacks for them in the first place. Although it
would be possible to do something similar for alarm timers, it's simpler
to handle this as a special case in the timeout.
Prior to this patch, the alarm timer would ignore the sigev_notify value
and try to deliver signals to the process anyway. Even worse, the
sanity check for the value of sigev_signo is skipped when SIGEV_NONE was
specified, so the signal number could be bogus. If sigev_signo was an
unitialized value (as it often would be if SIGEV_NONE is used), then
it's hard to predict which signal will be sent.
Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: Richard Larocque <rlarocque@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Returns the time remaining for an alarm timer, rather than the time at
which it is scheduled to expire. If the timer has already expired or it
is not currently scheduled, the it_value's members are set to zero.
This new behavior matches that of the other posix-timers and the POSIX
specifications.
This is a change in user-visible behavior, and may break existing
applications. Hopefully, few users rely on the old incorrect behavior.
Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: Richard Larocque <rlarocque@google.com>
[jstultz: minor style tweak]
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Sharvil noticed with the posix timer_settime interface, using the
CLOCK_REALTIME_ALARM or CLOCK_BOOTTIME_ALARM clockid, if the users
tried to specify a relative time timer, it would incorrectly be
treated as absolute regardless of the state of the flags argument.
This patch corrects this, properly checking the absolute/relative flag,
as well as adds further error checking that no invalid flag bits are set.
Reported-by: Sharvil Nanavati <sharvil@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sharvil Nanavati <sharvil@google.com>
Cc: stable <stable@vger.kernel.org> #3.0+
Link: http://lkml.kernel.org/r/1404767171-6902-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Export symbol of alarmtimer_get_rtcdev so that it is used by
any driver when built as module like,
drivers/staging/android/alarm-dev.c.
CC: John Stultz <john.stultz@linaro.org>
CC: Marcus Gelderie <redmnic@gmail.com>
Signed-off-by: Pramod Gurav <pramod.gurav.etc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Fedora Ruby maintainer reported latest Ruby doesn't work on Fedora Rawhide
on ARM. (http://bugs.ruby-lang.org/issues/9008)
Because of, commit 1c6b39ad3f (alarmtimers: Return -ENOTSUPP if no
RTC device is present) intruduced to return ENOTSUPP when
clock_get{time,res} can't find a RTC device. However this is incorrect.
First, ENOTSUPP isn't exported to userland (ENOTSUP or EOPNOTSUP are the
closest userland equivlents).
Second, Posix and Linux man pages agree that clock_gettime and
clock_getres should return EINVAL if clk_id argument is invalid.
While the arugment that the clockid is valid, but just not supported
on this hardware could be made, this is just a technicality that
doesn't help userspace applicaitons, and only complicates error
handling.
Thus, this patch changes the code to use EINVAL.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: stable <stable@vger.kernel.org> #3.0 and up
Reported-by: Vit Ondruch <v.ondruch@tiscali.cz>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
[jstultz: Tweaks to commit message to include full rational]
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Export symbols so they can be used by
drivers/staging/android/alarm-dev.c if it is built as a module.
So far alarm-dev is built-in but module support is planned (see
drivers/staging/android/TODO).
Signed-off-by: Marcus Gelderie <redmnic@gmail.com>
[jstultz: tweaked commit message, also export newly added functions]
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Add functions needed for hooking up alarmtimer to timerfd:
* alarm_restart: Similar to hrtimer_restart, restart an alarmtimer after
the expires time has already been updated (as with alarm_forward).
* alarm_forward_now: Similar to hrtimer_forward_now, move the expires
time forward to an interval from the current time of the associated clock.
* alarm_start_relative: Start an alarmtimer with an expires time relative to
the current time of the associated clock.
* alarm_expires_remaining: Similar to hrtimer_expires_remaining, return the
amount of time remaining until alarm expiry.
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Now that alarmtimer_remove has been simplified, change
its name to _dequeue to better match its paired _enqueue
function.
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Colin Cross <ccross@android.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Arve Hjønnevåg reported numerous crashes from the
"BUG_ON(timer->state != HRTIMER_STATE_CALLBACK)" check
in __run_hrtimer after it called alarmtimer_fired.
It ends up the alarmtimer code was not properly handling
possible failures of hrtimer_try_to_cancel, and because
these faulres occur when the underlying base hrtimer is
being run, this limits the ability to properly handle
modifications to any alarmtimers on that base.
Because much of the logic duplicates the hrtimer logic,
it seems that we might as well have a per-alarmtimer
hrtimer, and avoid the extra complextity of trying to
multiplex many alarmtimers off of one hrtimer.
Thus this patch moves the hrtimer to the alarm structure
and simplifies the management logic.
Changelog:
v2:
* Includes a fix for double alarm_start calls found by
Arve
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Colin Cross <ccross@android.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Arve Hjønnevåg <arve@android.com>
Tested-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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alarmtimer suspend return -EBUSY if the next alarm will fire in less
than 2 seconds. This allows one RTC seconds tick to occur subsequent
to this check before the alarm wakeup time is set, ensuring the wakeup
time is still in the future (assuming the RTC does not tick one more
second prior to setting the alarm).
If suspend is rejected due to an imminent alarm, hold a wakeup source
for 2 seconds to process the alarm prior to reattempting suspend.
If setting the alarm incurs an -ETIME for an alarm set in the past,
or any other problem setting the alarm, abort suspend and hold a
wakelock for 1 second while the alarm is allowed to be serviced or
other hopefully transient conditions preventing the alarm clear up.
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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The Android alarm interface provides a settime call that sets both
the alarmtimer RTC device and CLOCK_REALTIME to the same value.
Since there may be multiple rtc devices, provide a hook to access the
one the alarmtimer infrastructure is using.
CC: Colin Cross <ccross@android.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Android Kernel Team <kernel-team@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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rtc_timer_init() is not available when CONFIG_RTC_CLASS=n. Provide a
proper wrapper in the RTC section of alarmtimer.c
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
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jonghwan Choi reported seeing warnings with the alarmtimer
code at suspend/resume time, and pointed out that the
rtctimer isn't being properly initialized.
This patch corrects this issue.
Reported-by: jonghwan Choi <jhbird.choi@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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The expiry function compares the timer against current time and does
not expire the timer when the expiry time is >= now. That's wrong. If
the timer is set for now, then it must expire.
Make the condition expiry > now for breaking out the loop.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: stable@kernel.org
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commit 8bc0daf (alarmtimers: Rework RTC device selection using class
interface) did not implement required error checks. Add them.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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This allows cleaner detection of the RTC device being registered, rather
then probing any time someone calls alarmtimer_get_rtcdev.
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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There's a number of edge cases when cancelling a alarm, so
to be sure we accurately do so, introduce try_to_cancel, which
returns proper failure errors if it cannot. Also modify cancel
to spin until the alarm is properly disabled.
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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In order to allow for functionality like try_to_cancel, add
more refined state tracking (similar to hrtimers).
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Now that periodic alarmtimers are managed by the handler function,
remove the period value from the alarm structure and let the handlers
manage the interval on their own.
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Now that the alarmtimers code has been refactored, the interval
cap limit can be removed.
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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In order to avoid wasting time expiring and re-adding very high freq
periodic alarmtimers, introduce alarm_forward() which is similar to
hrtimer_forward and moves the timer to the next future expiration time
and returns the number of overruns.
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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This patch pushes the periodic alarmtimer re-arming down into the alarmtimer
handler, mimicking how hrtimers handle this.
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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In order to properly fix the denial of service issue with high freq
periodic alarm timers, we need to push the re-arming logic into the
alarm timer handler, much as the hrtimer code does.
This patch introduces alarmtimer_restart enum and changes the
alarmtimer handler declarations to use it as a return value. Further,
to ease following changes, it extends the alarmtimer handler functions
to also take the time at expiration. No logic is yet modified.
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Its possible to jam up the alarm timers by setting very small interval
timers, which will cause the alarmtimer subsystem to spend all of its time
firing and restarting timers. This can effectivly lock up a box.
A deeper fix is needed, closely mimicking the hrtimer code, but for now
just cap the interval to 100us to avoid userland hanging the system.
CC: Thomas Gleixner <tglx@linutronix.de>
CC: stable@kernel.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Following common_timer_get, zero out the itimerspec passed in.
CC: Thomas Gleixner <tglx@linutronix.de>
CC: stable@kernel.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
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We don't check if old_setting is non null before assigning it, so
correct this.
CC: Thomas Gleixner <tglx@linutronix.de>
CC: stable@kernel.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Toralf Förster and Richard Weinberger noted that if there is
no RTC device, the alarm timers core prints out an annoying
"ALARM timers will not wake from suspend" message.
This warning has been removed in a previous patch, however
the issue still remains: The original idea was to support
alarm timers even if there was no rtc device, as long as the
system didn't go into suspend.
However, after further consideration, communicating to the application
that alarmtimers are not fully functional seems like the better
solution.
So this patch makes it so we return -ENOTSUPP to any posix _ALARM
clockid calls if there is no backing RTC device on the system.
Further this changes the behavior where when there is no rtc device
we will check for one on clock_getres, clock_gettime, timer_create,
and timer_nsleep instead of on suspend.
CC: Toralf Förster <toralf.foerster@gmx.de>
CC: Richard Weinberger <richard@nod.at
CC: Peter Zijlstra <peterz@infradead.org>
CC: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Toralf Förster <toralf.foerster@gmx.de>
Reported by: Richard Weinberger <richard@nod.at>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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The alarmtimers code currently picks a rtc device to use at
late init time. However, if your rtc driver is loaded as a module,
it may be registered after the alarmtimers late init code, leaving
the alarmtimers nonfunctional.
This patch moves the the rtcdevice selection to when we actually try
to use it, allowing us to make use of rtc modules that may have been
loaded at any point since bootup.
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Meelis Roos <mroos@ut.ee>
Reported-by: Meelis Roos <mroos@ut.ee>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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Instead of iterating over all possible timer bases avoid it by marking
the active bases in the cpu base.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
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class_find_device() takes a refcount on the rtc device. rtc_open()
takes another one, so we can drop it after the rtc_open() call.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
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alarmtimer_late_init() uses class_find_device() to find a alarm
capable rtc device. The match callback stores a pointer to the name in
the char pointer handed in from the call site. alarmtimer_late_init()
checks the char pointer for NULL, but the pointer is on the stack and
not initialized to NULL before the call. So it can have random content
when the match function did not identify a device, which leads to
random access in the following rtc_open() call where the pointer is
dereferenced
Instead of relying on the char pointer, check the return value of
class_find_device. If a device is found then the name pointer is valid
as well.
Reported-by: Ingo Molnar <mingo@elte.hu>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Ingo pointed out that the alarmtimers won't build if CONFIG_RTC_CLASS=n.
This patch adds proper ifdefs to the alarmtimer code to disable the rtc
usage if it is not built in.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Thomas asked about the delayed irq work in the alarmtimers code,
and I realized that it was a legacy from when the alarmtimer base
lock was a mutex (due to concerns that we'd be interacting with
the RTC device, which is protected by mutexes).
Since the alarmtimer base is now protected by a spinlock, we can
simply execute alarmtimer functions directly from the hrtimer
callback. Should any future alarmtimer functions sleep, they can
simply manage scheduling any delayed work themselves.
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
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