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2019-03-23tick: Remove outgoing CPU from broadcast masksThomas Gleixner1-2/+16
Valentin reported that unplugging a CPU occasionally results in a warning in the tick broadcast code which is triggered when an offline CPU is in the broadcast mask. This happens because the outgoing CPU is not removing itself from the broadcast masks, especially not from the broadcast_force_mask. The removal happens on the control CPU after the outgoing CPU is dead. It's a long standing issue, but the warning is harmless. Rework the hotplug mechanism so that the outgoing CPU removes itself from the broadcast masks after disabling interrupts and removing itself from the online mask. Reported-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Valentin Schneider <valentin.schneider@arm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1903211540180.1784@nanos.tec.linutronix.de
2018-11-23hrtimers/tick/clockevents: Remove sloppy license referencesThomas Gleixner1-3/+0
"For licencing details see kernel-base/COPYING" and similar license references have no value over the SPDX identifier. Remove them. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: John Stultz <john.stultz@linaro.org> Acked-by: Corey Minyard <cminyard@mvista.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Peter Anvin <hpa@zytor.com> Cc: Russell King <rmk+kernel@armlinux.org.uk> Cc: Richard Cochran <richardcochran@gmail.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: David Riley <davidriley@chromium.org> Cc: Colin Cross <ccross@android.com> Cc: Mark Brown <broonie@kernel.org> Link: https://lkml.kernel.org/r/20181031182252.963632760@linutronix.de
2018-11-23time: Add SPDX license identifiersThomas Gleixner1-0/+1
Update the time(r) core files files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Philippe Ombredanne, Kate Stewart and myself. The data has been created with two independent license scanners and manual inspection. The following files do not contain any direct license information and have been omitted from the big initial SPDX changes: timeconst.bc: The .bc files were not touched time.c, timer.c, timekeeping.c: Licence was deduced from EXPORT_SYMBOL_GPL As those files do not contain direct license references they fall under the project license, i.e. GPL V2 only. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: John Stultz <john.stultz@linaro.org> Acked-by: Corey Minyard <cminyard@mvista.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Russell King <rmk+kernel@armlinux.org.uk> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: David Riley <davidriley@chromium.org> Cc: Colin Cross <ccross@android.com> Cc: Mark Brown <broonie@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: https://lkml.kernel.org/r/20181031182252.879109557@linutronix.de
2018-11-23time: Remove useless filenames in top level commentsThomas Gleixner1-2/+0
Remove the pointless filenames in the top level comments. They have no value at all and just occupy space. While at it tidy up some of the comments and remove a stale one. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: John Stultz <john.stultz@linaro.org> Acked-by: Corey Minyard <cminyard@mvista.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Peter Anvin <hpa@zytor.com> Cc: Russell King <rmk+kernel@armlinux.org.uk> Cc: Richard Cochran <richardcochran@gmail.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: David Riley <davidriley@chromium.org> Cc: Colin Cross <ccross@android.com> Cc: Mark Brown <broonie@kernel.org> Link: https://lkml.kernel.org/r/20181031182252.794898238@linutronix.de
2018-11-05clockevents: Remove unnecessary unlikely()Yangtao Li1-9/+3
WARN_ON() and WARN_ON_ONCE() already contains an unlikely(), so it's not necessary to use unlikely. Signed-off-by: Yangtao Li <tiny.windzz@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20181104023104.2572-1-tiny.windzz@gmail.com
2018-08-02clockevents: Warn if cpu_all_mask is used as cpumaskSudeep Holla1-0/+6
Using cpu_all_mask in clockevents cpumask may result in issues while comparing multiple clockevent devices to choose the preferred one. On one of the platforms with 2 system (i.e. non per-CPU) timers with different ratings, having cpu_all_mask for one of the device resulted in a boot hang due to a endless loop in clockevents_notify_released() as both were clocksources were selected as preferred. In order to prevent such issues in the future, warn if any clockevent driver sets cpu_all_mask as it's cpumask and just override it to use cpu_possible_mask. All the existing occurrences of cpu_all_mask are already replaced with cpu_possible_mask. Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arm-kernel@lists.infradead.org Link: https://lkml.kernel.org/r/1531308264-24220-3-git-send-email-sudeep.holla@arm.com
2017-10-19clockevents: Retry programming min delta up to 10 timesJames Hogan1-8/+13
When CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST=n, the call path hrtimer_reprogram -> clockevents_program_event -> clockevents_program_min_delta will not retry if the clock event driver returns -ETIME. If the driver could not satisfy the program_min_delta for any reason, the lack of a retry means the CPU may not receive a tick interrupt, potentially until the counter does a full period. This leads to rcu_sched timeout messages as the stalled CPU is detected by other CPUs, and other issues if the CPU is holding locks or other resources at the point at which it stalls. There have been a couple of observed mechanisms through which a clock event driver could not satisfy the requested min_delta and return -ETIME. With the MIPS GIC driver, the shared execution resource within MT cores means inconventient latency due to execution of instructions from other hardware threads in the core, within gic_next_event, can result in an event being set in the past. Additionally under virtualisation it is possible to get unexpected latency during a clockevent device's set_next_event() callback which can make it return -ETIME even for a delta based on min_delta_ns. It isn't appropriate to use MIN_ADJUST in the virtualisation case as occasional hypervisor induced high latency will cause min_delta_ns to quickly increase to the maximum. Instead, borrow the retry pattern from the MIN_ADJUST case, but without making adjustments. Retry up to 10 times, each time increasing the attempted delta by min_delta, before giving up. [ Matt: Reworked the loop and made retry increase the delta. ] Signed-off-by: James Hogan <jhogan@kernel.org> Signed-off-by: Matt Redfearn <matt.redfearn@mips.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mips@linux-mips.org Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: "Martin Schwidefsky" <schwidefsky@de.ibm.com> Cc: James Hogan <james.hogan@mips.com> Link: https://lkml.kernel.org/r/1508422643-6075-1-git-send-email-matt.redfearn@mips.com
2017-03-23clockevents: Make clockevents_config() staticNicolai Stange1-1/+1
A clockevent device's rate should be configured before or at registration and changed afterwards through clockevents_update_freq() only. For the configuration at registration, we already have clockevents_config_and_register(). Right now, there are no clockevents_config() users outside of the clockevents core. To mitigiate the risk of drivers errorneously reconfiguring their rates through clockevents_config() *after* device registration, make clockevents_config() static. Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
2016-12-25ktime: Get rid of the unionThomas Gleixner1-3/+3
ktime is a union because the initial implementation stored the time in scalar nanoseconds on 64 bit machine and in a endianess optimized timespec variant for 32bit machines. The Y2038 cleanup removed the timespec variant and switched everything to scalar nanoseconds. The union remained, but become completely pointless. Get rid of the union and just keep ktime_t as simple typedef of type s64. The conversion was done with coccinelle and some manual mopping up. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
2016-07-19clockevents: Make clockevents_subsys staticBen Dooks1-1/+1
The clockevents_subsys struct is used for sysfs support and is not declared or used outside the file it is defined in. Fix the following warning by making it static: kernel/time/clockevents.c:648:17: warning: symbol 'clockevents_subsys' was not declared. Should it be static? Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Cc: linux-kernel@lists.codethink.co.uk Link: http://lkml.kernel.org/r/1466178974-7105-1-git-send-email-ben.dooks@codethink.co.uk Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-09-14clockevents: Remove unused set_mode() callbackViresh Kumar1-41/+1
All users are migrated to the per-state callbacks, get rid of the unused interface and the core support code. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linaro-kernel@lists.linaro.org Cc: John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/fd60de14cf6d125489c031207567bb255ad946f6.1441943991.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-07clockevents: Allow set-state callbacks to be optionalViresh Kumar1-15/+9
Its mandatory for the drivers to provide set_state_{oneshot|periodic}() (only if related modes are supported) and set_state_shutdown() callbacks today, if they are implementing the new set-state interface. But this leads to unnecessary noop callbacks for drivers which don't want to implement them. Over that, it will lead to a full function call for nothing really useful. Lets make all set-state callbacks optional. Suggested-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: http://lkml.kernel.org/r/1436256875-15562-1-git-send-email-daniel.lezcano@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-18clockevents: Check state instead of mode in suspend/resume pathViresh Kumar1-2/+2
CLOCK_EVT_MODE_* macros are present for backward compatibility (as most of the drivers are still using old ->set_mode() interface). These macro's shouldn't be used anymore in code, that is common to both driver interfaces, i.e. ->set_mode() and ->set_state_*(). Drivers implementing ->set_state_*() interface, which have their clkevt->mode set to 0 (clkevt device structures are normally globally defined), will not participate in suspend/resume as they will always be marked as UNUSED. Fix this by checking state of the clockevent device instead of mode, which is updated for both the interfaces. Fixes: ac34ad27fc16 ("clockevents: Do not suspend/resume if unused") Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: linaro-kernel@lists.linaro.org Cc: alexandre.belloni@free-electrons.com Cc: sylvain.rochet@finsecur.com Link: http://lkml.kernel.org/r/a1964eef6e8a47d02b1ff9083c6c91f73f0ff643.1434537215.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-06-02clockevents: Use set/get state helper functionsThomas Gleixner1-5/+6
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org>
2015-06-02clockevents: Provide functions to set and get the stateThomas Gleixner1-9/+9
We want to rename dev->state, so provide proper get and set functions. Rename clockevents_set_state() to clockevents_switch_state() to avoid confusion. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org>
2015-06-02clockevents: Use helpers to check the state of a clockevent deviceViresh Kumar1-12/+12
Use accessor functions to check the state of clockevent devices in core code. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: linaro-kernel@lists.linaro.org Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/fa2b9869fd17f210eaa156ec2b594efd0230b6c7.1432192527.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-05-27clockevents: Do not suspend/resume if unusedAlexandre Belloni1-2/+2
There is no point in calling suspend/resume for unused clockevents as they are already stopped and disabled. This is really important for AT91 as the hardware is a trainwreck and takes ages to synchronize. Reported-by: Sylvain Rochet <sylvain.rochet@finsecur.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Nicolas Ferre <nicolas.ferre@atmel.com> Cc: Boris Brezillon <boris.brezillon@free-electrons.com> Cc: Maxime Ripard <maxime.ripard@free-electrons.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1421399151-26800-1-git-send-email-alexandre.belloni@free-electrons.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-05-19clockevents: Stop unused clockevent devicesViresh Kumar1-0/+4
To avoid getting spurious interrupts on a tickless CPU, clockevent device can now be stopped by switching to ONESHOT_STOPPED state. The natural place for handling this transition is tick_program_event(). On 'expires == KTIME_MAX', we skip programming the event and so we need to fix such call sites as well, to always call tick_program_event() irrespective of the expires value. Once the clockevent device is required again, check if it was earlier put into ONESHOT_STOPPED state. If yes, switch its state to ONESHOT before programming its event. To make sure we haven't missed any corner case, add a WARN() for the case where we try to reprogram clockevent device while we aren't configured in ONESHOT_STOPPED state. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: linaro-kernel@lists.linaro.org Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Kevin Hilman <khilman@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/5146b07be7f0bc497e0ebae036590ec2fa73e540.1428031396.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-05-19clockevents: Introduce CLOCK_EVT_STATE_ONESHOT_STOPPED stateViresh Kumar1-1/+13
When no timers/hrtimers are pending, the expiry time is set to a special value: 'KTIME_MAX'. This normally happens with NO_HZ_{IDLE|FULL} in both LOWRES/HIGHRES modes. When 'expiry == KTIME_MAX', we either cancel the 'tick-sched' hrtimer (NOHZ_MODE_HIGHRES) or skip reprogramming clockevent device (NOHZ_MODE_LOWRES). But, the clockevent device is already reprogrammed from the tick-handler for next tick. As the clock event device is programmed in ONESHOT mode it will at least fire one more time (unnecessarily). Timers on few implementations (like arm_arch_timer, etc.) only support PERIODIC mode and their drivers emulate ONESHOT over that. Which means that on these platforms we will get spurious interrupts periodically (at last programmed interval rate, normally tick rate). In order to avoid spurious interrupts, the clockevent device should be stopped or its interrupts should be masked. A simple (yet hacky) solution to get this fixed could be: update hrtimer_force_reprogram() to always reprogram clockevent device and update clockevent drivers to STOP generating events (or delay it to max time) when 'expires' is set to KTIME_MAX. But the drawback here is that every clockevent driver has to be hacked for this particular case and its very easy for new ones to miss this. However, Thomas suggested to add an optional state ONESHOT_STOPPED to solve this problem: lkml.org/lkml/2014/5/9/508. This patch adds support for ONESHOT_STOPPED state in clockevents core. It will only be available to drivers that implement the state-specific callbacks instead of the legacy ->set_mode() callback. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com> Cc: linaro-kernel@lists.linaro.org Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Kevin Hilman <khilman@linaro.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/b8b383a03ac07b13312c16850b5106b82e4245b5.1428031396.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-05-09Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds1-5/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fix from Thomas Gleixner: "A simple fix to actually shut down a detached device instead of keeping it active" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clockevents: Shutdown detached clockevent device
2015-04-24clockevents: Shutdown detached clockevent deviceViresh Kumar1-5/+1
A clockevent device is marked DETACHED when it is replaced by another clockevent device. The device is shutdown properly for drivers that implement legacy ->set_mode() callback, as we call ->set_mode() for CLOCK_EVT_MODE_UNUSED as well. But for the new per-state callback interface, we skip shutting down the device, as we thought its an internal state change. That wasn't correct. The effect is that the device is left programmed in oneshot or periodic mode. Fall-back to 'case CLOCK_EVT_STATE_SHUTDOWN', to shutdown the device. Fixes: bd624d75db21 "clockevents: Introduce mode specific callbacks" Reported-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: linaro-kernel@lists.linaro.org Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/eef0a91c51b74d4e52c8e5a95eca27b5a0563f07.1428650683.git.viresh.kumar@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-04-21Merge tag 'char-misc-4.1-rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc driver updates from Greg KH: "Here's the big char/misc driver patchset for 4.1-rc1. Lots of different driver subsystem updates here, nothing major, full details are in the shortlog. All of this has been in linux-next for a while" * tag 'char-misc-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (133 commits) mei: trace: remove unused TRACE_SYSTEM_STRING DTS: ARM: OMAP3-N900: Add lis3lv02d support Documentation: DT: lis302: update wakeup binding lis3lv02d: DT: add wakeup unit 2 and wakeup threshold lis3lv02d: DT: use s32 to support negative values Drivers: hv: hv_balloon: correctly handle num_pages>INT_MAX case Drivers: hv: hv_balloon: correctly handle val.freeram<num_pages case mei: replace check for connection instead of transitioning mei: use mei_cl_is_connected consistently mei: fix mei_poll operation hv_vmbus: Add gradually increased delay for retries in vmbus_post_msg() Drivers: hv: hv_balloon: survive ballooning request with num_pages=0 Drivers: hv: hv_balloon: eliminate jumps in piecewiese linear floor function Drivers: hv: hv_balloon: do not online pages in offline blocks hv: remove the per-channel workqueue hv: don't schedule new works in vmbus_onoffer()/vmbus_onoffer_rescind() hv: run non-blocking message handlers in the dispatch tasklet coresight: moving to new "hwtracing" directory coresight-tmc: Adding a status interface to sysfs coresight: remove the unnecessary configuration coresight-default-sink ...
2015-04-03clockevents: Cleanup dead cpu explicitelyThomas Gleixner1-30/+21
clockevents_notify() is a leftover from the early design of the clockevents facility. It's really not a notification mechanism, it's a multiplex call. We are way better off to have explicit calls instead of this monstrosity. Split out the cleanup function for a dead cpu and invoke it directly from the cpu down code. Make it conditional on CPU_HOTPLUG as well. Temporary change, will be refined in the future. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [ Rebased, added clockevents_notify() removal ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1735025.raBZdQHM3m@vostro.rjw.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-03clockevents: Make tick handover explicitThomas Gleixner1-4/+0
clockevents_notify() is a leftover from the early design of the clockevents facility. It's really not a notification mechanism, it's a multiplex call. We are way better off to have explicit calls instead of this monstrosity. Split out the tick_handover call and invoke it explicitely from the hotplug code. Temporary solution will be cleaned up in later patches. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [ Rebase ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1658173.RkEEILFiQZ@vostro.rjw.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-03clockevents: Remove broadcast oneshot control leftoversRafael J. Wysocki1-7/+0
Now that all users are converted over to explicit calls into the clockevents state machine, remove the notification chain leftovers. Original-from: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/14018863.NQUzkFuafr@vostro.rjw.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-03clockevents: Provide explicit broadcast oneshot control functionsThomas Gleixner1-1/+3
clockevents_notify() is a leftover from the early design of the clockevents facility. It's really not a notification mechanism, it's a multiplex call. We are way better off to have explicit calls instead of this monstrosity. Split out the broadcast oneshot control into a separate function and provide inline helpers. Switch clockevents_notify() over. This will go away once all callers are converted. This also gets rid of the nested locking of clockevents_lock and broadcast_lock. The broadcast oneshot control functions do not require clockevents_lock. Only the managing functions (setup/shutdown/suspend/resume of the broadcast device require clockevents_lock. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Alexandre Courbot <gnurou@gmail.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Len Brown <lenb@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Tony Lindgren <tony@atomide.com> Link: http://lkml.kernel.org/r/13000649.8qZuEDV0OA@vostro.rjw.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-03clockevents: Remove the broadcast control leftoversThomas Gleixner1-10/+0
All users converted. Remove the notify leftovers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/2076318.76XJZ8QYP3@vostro.rjw.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-03clockevents: Provide explicit broadcast control functionsThomas Gleixner1-1/+5
clockevents_notify() is a leftover from the early design of the clockevents facility. It's really not a notification mechanism, it's a multiplex call. We are way better off to have explicit calls instead of this monstrosity. Split out the broadcast control into a separate function and provide inline helpers. Switch clockevents_notify() over. This will go away once all callers are converted. This also gets rid of the nested locking of clockevents_lock and broadcast_lock. The broadcast control functions do not require clockevents_lock. Only the managing functions (setup/shutdown/suspend/resume of the broadcast device require clockevents_lock. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Len Brown <lenb@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tony Lindgren <tony@atomide.com> Link: http://lkml.kernel.org/r/8086559.ttsuS0n1Xr@vostro.rjw.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-01clockevents: Make suspend/resume calls explicitThomas Gleixner1-9/+0
clockevents_notify() is a leftover from the early design of the clockevents facility. It's really not a notification mechanism, it's a multiplex call. We are way better off to have explicit calls instead of this monstrosity. Split out the suspend/resume() calls and invoke them directly from the call sites. No locking required at this point because these calls happen with interrupts disabled and a single cpu online. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [ Rebased on top of 4.0-rc5. ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/713674030.jVm1qaHuPf@vostro.rjw.lan [ Rebased on top of latest timers/core. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-01clockevents: Remove extra local_irq_save() in clockevents_exchange_device()Thomas Gleixner1-5/+2
Called with 'clockevents_lock' held and interrupts disabled already. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/51005827.yXt5tjZMBs@vostro.rjw.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-01clockevents: Remove CONFIG_GENERIC_CLOCKEVENTS_BUILDThomas Gleixner1-3/+0
This option was for simpler migration to the clock events code. Most architectures have been converted and the option has been disfunctional as a standalone option for quite some time. Remove it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/5021859.jl9OC1medj@vostro.rjw.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27clockevents: Don't validate dev->mode against CLOCK_EVT_MODE_UNUSED for new ↵Viresh Kumar1-1/+2
interface It was a requirement in the legacy interface that drivers must initialize ->mode field to 'CLOCK_EVT_MODE_UNUSED'. This field isn't used anymore by the new interface and so should be only checked for the legacy interface. Probably it can be dropped as well as core doesn't rely on it anymore, but lets keep it to support legacy interface. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Kevin Hilman <khilman@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: linaro-kernel@lists.linaro.org Cc: linaro-networking@linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/c6604fa1a77fe1fc8dcab87769857228fb1dadd5.1425037853.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27clockevents: Manage device's state separately for the coreViresh Kumar1-46/+53
'enum clock_event_mode' is used for two purposes today: - to pass mode to the driver of clockevent device::set_mode(). - for managing state of the device for clockevents core. For supporting new modes/states we have moved away from the legacy set_mode() callback to new per-mode/state callbacks. New modes/states shouldn't be exposed to the legacy (now OBSOLOTE) callbacks and so we shouldn't add new states to 'enum clock_event_mode'. Lets have separate enums for the two use cases mentioned above. Keep using the earlier enum for legacy set_mode() callback and mark it OBSOLETE. And add another enum to clearly specify the possible states of a clockevent device. This also renames the newly added per-mode callbacks to reflect state changes. We haven't got rid of 'mode' member of 'struct clock_event_device' as it is used by some of the clockevent drivers and it would automatically die down once we migrate those drivers to the new interface. It ('mode') is only updated now for the drivers using the legacy interface. Suggested-by: Peter Zijlstra <peterz@infradead.org> Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Kevin Hilman <khilman@linaro.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: linaro-kernel@lists.linaro.org Cc: linaro-networking@linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/b6b0143a8a57bd58352ad35e08c25424c879c0cb.1425037853.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27clockevents: Handle tick device's resume separatelyViresh Kumar1-9/+21
Upcoming patch will redefine possible states of a clockevent device. The RESUME mode is a special case only for tick's clockevent devices. In future it can be replaced by ->resume() callback already available for clockevent devices. Lets handle it separately so that clockevents_set_mode() only handles states valid across all devices. This also renames set_mode_resume() to tick_resume() to make it more explicit. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Kevin Hilman <khilman@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: linaro-kernel@lists.linaro.org Cc: linaro-networking@linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/c1b0112410870f49e7bf06958e1483eac6c15e20.1425037853.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-01clockevents: export clockevents_unbind_device instead of clockevents_unbindVitaly Kuznetsov1-1/+1
It looks like clockevents_unbind is being exported by mistake as: - it is static; - it is not listed in include/linux/clockchips.h; - EXPORT_SYMBOL_GPL(clockevents_unbind) follows clockevents_unbind_device() implementation. I think clockevents_unbind_device should be exported instead. This is going to be used to teardown Hyper-V clockevent devices on module unload. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-02-18clockevents: Introduce mode specific callbacksViresh Kumar1-2/+86
It is not possible for the clockevents core to know which modes (other than those with a corresponding feature flag) are supported by a particular implementation. And drivers are expected to handle transition to all modes elegantly, as ->set_mode() would be issued for them unconditionally. Now, adding support for a new mode complicates things a bit if we want to use the legacy ->set_mode() callback. We need to closely review all clockevents drivers to see if they would break on addition of a new mode. And after such reviews, it is found that we have to do non-trivial changes to most of the drivers [1]. Introduce mode-specific set_mode_*() callbacks, some of which the drivers may or may not implement. A missing callback would clearly convey the message that the corresponding mode isn't supported. A driver may still choose to keep supporting the legacy ->set_mode() callback, but ->set_mode() wouldn't be supporting any new modes beyond RESUME. If a driver wants to benefit from using a new mode, it would be required to migrate to the mode specific callbacks. The legacy ->set_mode() callback and the newly introduced mode-specific callbacks are mutually exclusive. Only one of them should be supported by the driver. Sanity check is done at the time of registration to distinguish between optional and required callbacks and to make error recovery and handling simpler. If the legacy ->set_mode() callback is provided, all mode specific ones would be ignored by the core but a warning is thrown if they are present. Call sites calling ->set_mode() directly are also updated to use __clockevents_set_mode() instead, as ->set_mode() may not be available anymore for few drivers. [1] https://lkml.org/lkml/2014/12/9/605 [2] https://lkml.org/lkml/2015/1/23/255 Suggested-by: Thomas Gleixner <tglx@linutronix.de> [2] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: linaro-kernel@lists.linaro.org Cc: linaro-networking@linaro.org Link: http://lkml.kernel.org/r/792d59a40423f0acffc9bb0bec9de1341a06fa02.1423788565.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-10-25clockevents: Prevent shift out of boundsThomas Gleixner1-1/+1
Andrey reported that on a kernel with UBSan enabled he found: UBSan: Undefined behaviour in ../kernel/time/clockevents.c:75:34 I guess it should be 1ULL here instead of 1U: (!ismax || evt->mult <= (1U << evt->shift))) That's indeed the correct solution because shift might be 32. Reported-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-08-01timer: Fix lock inversion between hrtimer_bases.lock and scheduler locksJan Kara1-4/+6
clockevents_increase_min_delta() calls printk() from under hrtimer_bases.lock. That causes lock inversion on scheduler locks because printk() can call into the scheduler. Lockdep puts it as: ====================================================== [ INFO: possible circular locking dependency detected ] 3.15.0-rc8-06195-g939f04b #2 Not tainted ------------------------------------------------------- trinity-main/74 is trying to acquire lock: (&port_lock_key){-.....}, at: [<811c60be>] serial8250_console_write+0x8c/0x10c but task is already holding lock: (hrtimer_bases.lock){-.-...}, at: [<8103caeb>] hrtimer_try_to_cancel+0x13/0x66 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (hrtimer_bases.lock){-.-...}: [<8104a942>] lock_acquire+0x92/0x101 [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e [<8103c918>] __hrtimer_start_range_ns+0x1c/0x197 [<8107ec20>] perf_swevent_start_hrtimer.part.41+0x7a/0x85 [<81080792>] task_clock_event_start+0x3a/0x3f [<810807a4>] task_clock_event_add+0xd/0x14 [<8108259a>] event_sched_in+0xb6/0x17a [<810826a2>] group_sched_in+0x44/0x122 [<81082885>] ctx_sched_in.isra.67+0x105/0x11f [<810828e6>] perf_event_sched_in.isra.70+0x47/0x4b [<81082bf6>] __perf_install_in_context+0x8b/0xa3 [<8107eb8e>] remote_function+0x12/0x2a [<8105f5af>] smp_call_function_single+0x2d/0x53 [<8107e17d>] task_function_call+0x30/0x36 [<8107fb82>] perf_install_in_context+0x87/0xbb [<810852c9>] SYSC_perf_event_open+0x5c6/0x701 [<810856f9>] SyS_perf_event_open+0x17/0x19 [<8142f8ee>] syscall_call+0x7/0xb -> #4 (&ctx->lock){......}: [<8104a942>] lock_acquire+0x92/0x101 [<8142f04c>] _raw_spin_lock+0x21/0x30 [<81081df3>] __perf_event_task_sched_out+0x1dc/0x34f [<8142cacc>] __schedule+0x4c6/0x4cb [<8142cae0>] schedule+0xf/0x11 [<8142f9a6>] work_resched+0x5/0x30 -> #3 (&rq->lock){-.-.-.}: [<8104a942>] lock_acquire+0x92/0x101 [<8142f04c>] _raw_spin_lock+0x21/0x30 [<81040873>] __task_rq_lock+0x33/0x3a [<8104184c>] wake_up_new_task+0x25/0xc2 [<8102474b>] do_fork+0x15c/0x2a0 [<810248a9>] kernel_thread+0x1a/0x1f [<814232a2>] rest_init+0x1a/0x10e [<817af949>] start_kernel+0x303/0x308 [<817af2ab>] i386_start_kernel+0x79/0x7d -> #2 (&p->pi_lock){-.-...}: [<8104a942>] lock_acquire+0x92/0x101 [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e [<810413dd>] try_to_wake_up+0x1d/0xd6 [<810414cd>] default_wake_function+0xb/0xd [<810461f3>] __wake_up_common+0x39/0x59 [<81046346>] __wake_up+0x29/0x3b [<811b8733>] tty_wakeup+0x49/0x51 [<811c3568>] uart_write_wakeup+0x17/0x19 [<811c5dc1>] serial8250_tx_chars+0xbc/0xfb [<811c5f28>] serial8250_handle_irq+0x54/0x6a [<811c5f57>] serial8250_default_handle_irq+0x19/0x1c [<811c56d8>] serial8250_interrupt+0x38/0x9e [<810510e7>] handle_irq_event_percpu+0x5f/0x1e2 [<81051296>] handle_irq_event+0x2c/0x43 [<81052cee>] handle_level_irq+0x57/0x80 [<81002a72>] handle_irq+0x46/0x5c [<810027df>] do_IRQ+0x32/0x89 [<8143036e>] common_interrupt+0x2e/0x33 [<8142f23c>] _raw_spin_unlock_irqrestore+0x3f/0x49 [<811c25a4>] uart_start+0x2d/0x32 [<811c2c04>] uart_write+0xc7/0xd6 [<811bc6f6>] n_tty_write+0xb8/0x35e [<811b9beb>] tty_write+0x163/0x1e4 [<811b9cd9>] redirected_tty_write+0x6d/0x75 [<810b6ed6>] vfs_write+0x75/0xb0 [<810b7265>] SyS_write+0x44/0x77 [<8142f8ee>] syscall_call+0x7/0xb -> #1 (&tty->write_wait){-.....}: [<8104a942>] lock_acquire+0x92/0x101 [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e [<81046332>] __wake_up+0x15/0x3b [<811b8733>] tty_wakeup+0x49/0x51 [<811c3568>] uart_write_wakeup+0x17/0x19 [<811c5dc1>] serial8250_tx_chars+0xbc/0xfb [<811c5f28>] serial8250_handle_irq+0x54/0x6a [<811c5f57>] serial8250_default_handle_irq+0x19/0x1c [<811c56d8>] serial8250_interrupt+0x38/0x9e [<810510e7>] handle_irq_event_percpu+0x5f/0x1e2 [<81051296>] handle_irq_event+0x2c/0x43 [<81052cee>] handle_level_irq+0x57/0x80 [<81002a72>] handle_irq+0x46/0x5c [<810027df>] do_IRQ+0x32/0x89 [<8143036e>] common_interrupt+0x2e/0x33 [<8142f23c>] _raw_spin_unlock_irqrestore+0x3f/0x49 [<811c25a4>] uart_start+0x2d/0x32 [<811c2c04>] uart_write+0xc7/0xd6 [<811bc6f6>] n_tty_write+0xb8/0x35e [<811b9beb>] tty_write+0x163/0x1e4 [<811b9cd9>] redirected_tty_write+0x6d/0x75 [<810b6ed6>] vfs_write+0x75/0xb0 [<810b7265>] SyS_write+0x44/0x77 [<8142f8ee>] syscall_call+0x7/0xb -> #0 (&port_lock_key){-.....}: [<8104a62d>] __lock_acquire+0x9ea/0xc6d [<8104a942>] lock_acquire+0x92/0x101 [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e [<811c60be>] serial8250_console_write+0x8c/0x10c [<8104e402>] call_console_drivers.constprop.31+0x87/0x118 [<8104f5d5>] console_unlock+0x1d7/0x398 [<8104fb70>] vprintk_emit+0x3da/0x3e4 [<81425f76>] printk+0x17/0x19 [<8105bfa0>] clockevents_program_min_delta+0x104/0x116 [<8105c548>] clockevents_program_event+0xe7/0xf3 [<8105cc1c>] tick_program_event+0x1e/0x23 [<8103c43c>] hrtimer_force_reprogram+0x88/0x8f [<8103c49e>] __remove_hrtimer+0x5b/0x79 [<8103cb21>] hrtimer_try_to_cancel+0x49/0x66 [<8103cb4b>] hrtimer_cancel+0xd/0x18 [<8107f102>] perf_swevent_cancel_hrtimer.part.60+0x2b/0x30 [<81080705>] task_clock_event_stop+0x20/0x64 [<81080756>] task_clock_event_del+0xd/0xf [<81081350>] event_sched_out+0xab/0x11e [<810813e0>] group_sched_out+0x1d/0x66 [<81081682>] ctx_sched_out+0xaf/0xbf [<81081e04>] __perf_event_task_sched_out+0x1ed/0x34f [<8142cacc>] __schedule+0x4c6/0x4cb [<8142cae0>] schedule+0xf/0x11 [<8142f9a6>] work_resched+0x5/0x30 other info that might help us debug this: Chain exists of: &port_lock_key --> &ctx->lock --> hrtimer_bases.lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(hrtimer_bases.lock); lock(&ctx->lock); lock(hrtimer_bases.lock); lock(&port_lock_key); *** DEADLOCK *** 4 locks held by trinity-main/74: #0: (&rq->lock){-.-.-.}, at: [<8142c6f3>] __schedule+0xed/0x4cb #1: (&ctx->lock){......}, at: [<81081df3>] __perf_event_task_sched_out+0x1dc/0x34f #2: (hrtimer_bases.lock){-.-...}, at: [<8103caeb>] hrtimer_try_to_cancel+0x13/0x66 #3: (console_lock){+.+...}, at: [<8104fb5d>] vprintk_emit+0x3c7/0x3e4 stack backtrace: CPU: 0 PID: 74 Comm: trinity-main Not tainted 3.15.0-rc8-06195-g939f04b #2 00000000 81c3a310 8b995c14 81426f69 8b995c44 81425a99 8161f671 8161f570 8161f538 8161f559 8161f538 8b995c78 8b142bb0 00000004 8b142fdc 8b142bb0 8b995ca8 8104a62d 8b142fac 000016f2 81c3a310 00000001 00000001 00000003 Call Trace: [<81426f69>] dump_stack+0x16/0x18 [<81425a99>] print_circular_bug+0x18f/0x19c [<8104a62d>] __lock_acquire+0x9ea/0xc6d [<8104a942>] lock_acquire+0x92/0x101 [<811c60be>] ? serial8250_console_write+0x8c/0x10c [<811c6032>] ? wait_for_xmitr+0x76/0x76 [<8142f11d>] _raw_spin_lock_irqsave+0x2e/0x3e [<811c60be>] ? serial8250_console_write+0x8c/0x10c [<811c60be>] serial8250_console_write+0x8c/0x10c [<8104af87>] ? lock_release+0x191/0x223 [<811c6032>] ? wait_for_xmitr+0x76/0x76 [<8104e402>] call_console_drivers.constprop.31+0x87/0x118 [<8104f5d5>] console_unlock+0x1d7/0x398 [<8104fb70>] vprintk_emit+0x3da/0x3e4 [<81425f76>] printk+0x17/0x19 [<8105bfa0>] clockevents_program_min_delta+0x104/0x116 [<8105cc1c>] tick_program_event+0x1e/0x23 [<8103c43c>] hrtimer_force_reprogram+0x88/0x8f [<8103c49e>] __remove_hrtimer+0x5b/0x79 [<8103cb21>] hrtimer_try_to_cancel+0x49/0x66 [<8103cb4b>] hrtimer_cancel+0xd/0x18 [<8107f102>] perf_swevent_cancel_hrtimer.part.60+0x2b/0x30 [<81080705>] task_clock_event_stop+0x20/0x64 [<81080756>] task_clock_event_del+0xd/0xf [<81081350>] event_sched_out+0xab/0x11e [<810813e0>] group_sched_out+0x1d/0x66 [<81081682>] ctx_sched_out+0xaf/0xbf [<81081e04>] __perf_event_task_sched_out+0x1ed/0x34f [<8104416d>] ? __dequeue_entity+0x23/0x27 [<81044505>] ? pick_next_task_fair+0xb1/0x120 [<8142cacc>] __schedule+0x4c6/0x4cb [<81047574>] ? trace_hardirqs_off_caller+0xd7/0x108 [<810475b0>] ? trace_hardirqs_off+0xb/0xd [<81056346>] ? rcu_irq_exit+0x64/0x77 Fix the problem by using printk_deferred() which does not call into the scheduler. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-02-07time: Change the return type of clockevents_notify() to integerPreeti U Murthy1-3/+5
The broadcast framework can potentially be made use of by archs which do not have an external clock device as well. Then, it is required that one of the CPUs need to handle the broadcasting of wakeup IPIs to the CPUs in deep idle. As a result its local timers should remain functional all the time. For such a CPU, the BROADCAST_ENTER notification has to fail indicating that its clock device cannot be shutdown. To make way for this support, change the return type of tick_broadcast_oneshot_control() and hence clockevents_notify() to indicate such scenarios. Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: deepthi@linux.vnet.ibm.com Cc: paulmck@linux.vnet.ibm.com Cc: fweisbec@gmail.com Cc: paulus@samba.org Cc: srivatsa.bhat@linux.vnet.ibm.com Cc: svaidy@linux.vnet.ibm.com Cc: peterz@infradead.org Cc: benh@kernel.crashing.org Cc: rafael.j.wysocki@intel.com Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20140207080606.17187.78306.stgit@preeti.in.ibm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-02-07clockevents: Adjust timer interval when frequency changesSoren Brinkmann1-3/+6
clockevent devices in periodic mode are not updated when the frequency of the device changes. Issue a dev->set_mode() callback which forces the device to reevaluate the timer settings. Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com> Cc: linux-arm-kernel@lists.infradead.org Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Michal Simek <michal.simek@xilinx.com> Link: http://lkml.kernel.org/r/1391466877-28908-3-git-send-email-soren.brinkmann@xilinx.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-02-07clockevents: Serialize calls to clockevents_update_freq() in the coreThomas Gleixner1-7/+22
We can identify the broadcast device in the core and serialize all callers including interrupts on a different CPU against the update. Also, disabling interrupts is moved into the core allowing callers to leave interrutps enabled when calling clockevents_update_freq(). Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com> Cc: linux-arm-kernel@lists.infradead.org Cc: Soeren Brinkmann <soren.brinkmann@xilinx.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Michal Simek <michal.simek@xilinx.com> Link: http://lkml.kernel.org/r/1391466877-28908-2-git-send-email-soren.brinkmann@xilinx.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-11-12Merge branch 'timers-core-for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer changes from Ingo Molnar: "Main changes in this cycle were: - Updated full dynticks support. - Event stream support for architected (ARM) timers. - ARM clocksource driver updates. - Move arm64 to using the generic sched_clock framework & resulting cleanup in the generic sched_clock code. - Misc fixes and cleanups" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits) x86/time: Honor ACPI FADT flag indicating absence of a CMOS RTC clocksource: sun4i: remove IRQF_DISABLED clocksource: sun4i: Report the minimum tick that we can program clocksource: sun4i: Select CLKSRC_MMIO clocksource: Provide timekeeping for efm32 SoCs clocksource: em_sti: convert to clk_prepare/unprepare time: Fix signedness bug in sysfs_get_uname() and its callers timekeeping: Fix some trivial typos in comments alarmtimer: return EINVAL instead of ENOTSUPP if rtcdev doesn't exist clocksource: arch_timer: Do not register arch_sys_counter twice timer stats: Add a 'Collection: active/inactive' line to timer usage statistics sched_clock: Remove sched_clock_func() hook arch_timer: Move to generic sched_clock framework clocksource: tcb_clksrc: Remove IRQF_DISABLED clocksource: tcb_clksrc: Improve driver robustness clocksource: tcb_clksrc: Replace clk_enable/disable with clk_prepare_enable/disable_unprepare clocksource: arm_arch_timer: Use clocksource for suspend timekeeping clocksource: dw_apb_timer_of: Mark a few more functions as __init clocksource: Put nodes passed to CLOCKSOURCE_OF_DECLARE callbacks centrally arm: zynq: Enable arm_global_timer ...
2013-10-23clockevents: Sanitize ticks to nsec conversionThomas Gleixner1-15/+50
Marc Kleine-Budde pointed out, that commit 77cc982 "clocksource: use clockevents_config_and_register() where possible" caused a regression for some of the converted subarchs. The reason is, that the clockevents core code converts the minimal hardware tick delta to a nanosecond value for core internal usage. This conversion is affected by integer math rounding loss, so the backwards conversion to hardware ticks will likely result in a value which is less than the configured hardware limitation. The affected subarchs used their own workaround (SIGH!) which got lost in the conversion. The solution for the issue at hand is simple: adding evt->mult - 1 to the shifted value before the integer divison in the core conversion function takes care of it. But this only works for the case where for the scaled math mult/shift pair "mult <= 1 << shift" is true. For the case where "mult > 1 << shift" we can apply the rounding add only for the minimum delta value to make sure that the backward conversion is not less than the given hardware limit. For the upper bound we need to omit the rounding add, because the backwards conversion is always larger than the original latch value. That would violate the upper bound of the hardware device. Though looking closer at the details of that function reveals another bogosity: The upper bounds check is broken as well. Checking for a resulting "clc" value greater than KTIME_MAX after the conversion is pointless. The conversion does: u64 clc = (latch << evt->shift) / evt->mult; So there is no sanity check for (latch << evt->shift) exceeding the 64bit boundary. The latch argument is "unsigned long", so on a 64bit arch the handed in argument could easily lead to an unnoticed shift overflow. With the above rounding fix applied the calculation before the divison is: u64 clc = (latch << evt->shift) + evt->mult - 1; So we need to make sure, that neither the shift nor the rounding add is overflowing the u64 boundary. [ukl: move assignment to rnd after eventually changing mult, fix build issue and correct comment with the right math] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> Cc: Marc Kleine-Budde <mkl@pengutronix.de> Cc: nicolas.ferre@atmel.com Cc: Marc Pignat <marc.pignat@hevs.ch> Cc: john.stultz@linaro.org Cc: kernel@pengutronix.de Cc: Ronald Wahl <ronald.wahl@raritan.com> Cc: LAK <linux-arm-kernel@lists.infradead.org> Cc: Ludovic Desroches <ludovic.desroches@atmel.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1380052223-24139-1-git-send-email-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2013-10-18time: Fix signedness bug in sysfs_get_uname() and its callersPatrick Palka1-1/+1
sysfs_get_uname() is erroneously declared as returning size_t even though it may return a negative value, specifically -EINVAL. Its callers then check whether its return value is less than zero and indeed that is never the case for size_t. This patch changes sysfs_get_uname() to return ssize_t and makes sure its callers use ssize_t accordingly. Signed-off-by: Patrick Palka <patrick@parcs.ath.cx> [jstultz: Didn't apply cleanly, as a similar partial fix was also applied so had to resolve the collisions] Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-05-16clockevents: Implement unbind functionalityThomas Gleixner1-0/+125
Provide a sysfs interface to allow unbinding of clockevent devices. The device is unbound if it is unused or if there is a replacement device available. Unbinding of broadcast devices is not supported as we don't want to foster that nonsense. If no replacement device is available the unbind returns -EBUSY. Unbind is available from the kernel and through sysfs, which is necessary to drop the module refcount. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143436.499216659@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-05-16clockevents: Provide sysfs interfaceThomas Gleixner1-0/+86
Provide a simple sysfs interface for the clockevent devices. Show the current active clockevent device. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143436.371634778@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-05-16clockevents: Add module refcountThomas Gleixner1-0/+1
We want to be able to remove clockevent modules as well. Add a refcount so we don't remove a module with an active clock event device. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143436.307435149@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-05-16clockevents: Move the tick_notify() switch case to clockevents_notify()Thomas Gleixner1-1/+27
No need to call another function and have duplicated cases. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143436.235746557@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-05-16clockevents: Get rid of the notifier chainThomas Gleixner1-32/+3
7+ years and still a single user. Kill it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143436.098520211@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-01-14clockevents: export clockevents_config_and_register for module useShawn Guo1-0/+1
clockevents_config_and_register is a handy helper for clockevent drivers, some of which might support module build, so export the symbol. Signed-off-by: Shawn Guo <shawn.guo@linaro.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Olof Johansson <olof@lixom.net>