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2021-05-31timer_list: Print name of per-cpu wakeup deviceWill Deacon1-0/+7
With the introduction of per-cpu wakeup devices that can be used in preference to the broadcast timer, print the name of such devices when they are available. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210524221818.15850-6-will@kernel.org
2021-05-31tick/broadcast: Program wakeup timer when entering idle if requiredWill Deacon1-1/+43
When configuring the broadcast timer on entry to and exit from deep idle states, prefer a per-CPU wakeup timer if one exists. On entry to idle, stop the tick device and transfer the next event into the oneshot wakeup device, which will serve as the wakeup from idle. To avoid the overhead of additional hardware accesses on exit from idle, leave the timer armed and treat the inevitable interrupt as a (possibly spurious) tick event. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210524221818.15850-5-will@kernel.org
2021-05-31tick/broadcast: Prefer per-cpu oneshot wakeup timers to broadcastWill Deacon1-1/+58
Some SoCs have two per-cpu timer implementations where the timer with the higher rating stops in deep idle (i.e. suffers from CLOCK_EVT_FEAT_C3STOP) but is otherwise preferable to the timer with the lower rating. In such a design, selecting the higher rated devices relies on a global broadcast timer and IPIs to wake up from deep idle states. To avoid the reliance on a global broadcast timer and also to reduce the overhead associated with the IPI wakeups, extend tick_install_broadcast_device() to manage per-cpu wakeup timers separately from the broadcast device. For now, these timers remain unused. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210524221818.15850-4-will@kernel.org
2021-05-31tick/broadcast: Split __tick_broadcast_oneshot_control() into a helperWill Deacon1-13/+20
In preparation for adding support for per-cpu wakeup timers, split _tick_broadcast_oneshot_control() into a helper function which deals only with the broadcast timer management across idle transitions. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210524221818.15850-3-will@kernel.org
2021-05-31tick/broadcast: Drop unneeded CONFIG_GENERIC_CLOCKEVENTS_BROADCAST guardWill Deacon1-2/+0
tick-broadcast.o is only built if CONFIG_GENERIC_CLOCKEVENTS_BROADCAST=y so remove the redundant #ifdef guards around the definition of tick_receive_broadcast(). Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210524221818.15850-2-will@kernel.org
2021-04-16tick/broadcast: Allow late registered device to enter oneshot modeJindong Yue1-2/+14
The broadcast device is switched to oneshot mode when the system switches to oneshot mode. If a broadcast clock event device is registered after the system switched to oneshot mode, it will stay in periodic mode forever. Ensure that a late registered device which is selected as broadcast device is initialized in oneshot mode when the system already uses oneshot mode. [ tglx: Massage changelog ] Signed-off-by: Jindong Yue <jindong.yue@nxp.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210331083318.21794-1-jindong.yue@nxp.com
2021-03-22timekeeping, clocksource: Fix various typos in commentsIngo Molnar1-2/+2
Fix ~56 single-word typos in timekeeping & clocksource code comments. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Stephen Boyd <sboyd@kernel.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: linux-kernel@vger.kernel.org
2020-11-19tick: Get rid of tick_periodThomas Gleixner1-1/+1
The variable tick_period is initialized to NSEC_PER_TICK / HZ during boot and never updated again. If NSEC_PER_TICK is not an integer multiple of HZ this computation is less accurate than TICK_NSEC which has proper rounding in place. Aside of the inaccuracy there is no reason for having this variable at all. It's just a pointless indirection and all usage sites can just use the TICK_NSEC constant. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201117132006.766643526@linutronix.de
2020-11-19tick/broadcast: Serialize access to tick_next_periodThomas Gleixner1-3/+20
tick_broadcast_setup_oneshot() accesses tick_next_period twice without any serialization. This is wrong in two aspects: - Reading it twice might make the broadcast data inconsistent if the variable is updated concurrently. - On 32bit systems the access might see an partial update Protect it with jiffies_lock. That's safe as none of the callchains leading up to this function can create a lock ordering violation: timer interrupt run_local_timers() hrtimer_run_queues() hrtimer_switch_to_hres() tick_init_highres() tick_switch_to_oneshot() tick_broadcast_switch_to_oneshot() or tick_check_oneshot_change() tick_nohz_switch_to_nohz() tick_switch_to_oneshot() tick_broadcast_switch_to_oneshot() Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201117132006.061341507@linutronix.de
2020-08-23treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva1-1/+1
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2019-04-19tick: Fix typos in commentsLaurent Gauthier1-2/+2
Signed-off-by: Laurent Gauthier <laurent.gauthier@soccasys.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-03-29tick/broadcast: Fix warning about undefined tick_broadcast_oneshot_offline()Borislav Petkov1-0/+4
Randconfig builds with CONFIG_TICK_ONESHOT=y CONFIG_HOTPLUG_CPU=n trigger kernel/time/tick-broadcast.c:39:13: warning: ‘tick_broadcast_oneshot_offline’ \ declared ‘static’ but never defined [-Wunused-function] due to that function's definition missing. Move the CONFIG_HOTPLUG_CPU ifdeffery around its declaration too. Fixes: 1b72d4323798 ("tick: Remove outgoing CPU from broadcast masks") Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Mukesh Ojha <mojha@codeaurora.org> Cc: Valentin Schneider <valentin.schneider@arm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: x86@kernel.org Link: https://lkml.kernel.org/r/20190329110508.6621-1-bp@alien8.de
2019-03-23tick: Remove outgoing CPU from broadcast masksThomas Gleixner1-21/+19
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
2019-01-29timers: Mark expected switch fall-throughsGustavo A. R. Silva1-0/+1
In preparation to enabling -Wimplicit-fallthrough, mark switch cases where fall through is indeed expected. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Stephen Boyd <sboyd@kernel.org> Link: https://lkml.kernel.org/r/20190123081413.GA3949@embeddedor
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
2018-09-28tick/broadcast: Remove redundant checkPeng Hao1-2/+0
tick_device_is_functional() is called early in tick_broadcast_control(), so no need to call it again later. Signed-off-by: Peng Hao <peng.hao2@zte.com.cn> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: fweisbec@gmail.com Link: https://lkml.kernel.org/r/1538150608-2599-1-git-send-email-penghao122@sina.com.cn
2018-05-15tick/broadcast: Use for_each_cpu() specially on UP kernelsDexuan Cui1-0/+8
for_each_cpu() unintuitively reports CPU0 as set independent of the actual cpumask content on UP kernels. This causes an unexpected PIT interrupt storm on a UP kernel running in an SMP virtual machine on Hyper-V, and as a result, the virtual machine can suffer from a strange random delay of 1~20 minutes during boot-up, and sometimes it can hang forever. Protect if by checking whether the cpumask is empty before entering the for_each_cpu() loop. [ tglx: Use !IS_ENABLED(CONFIG_SMP) instead of #ifdeffery ] Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Josh Poulson <jopoulso@microsoft.com> Cc: "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: stable@vger.kernel.org Cc: Rakib Mullick <rakib.mullick@gmail.com> Cc: Jork Loeser <Jork.Loeser@microsoft.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: KY Srinivasan <kys@microsoft.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Link: https://lkml.kernel.org/r/KL1P15301MB000678289FE55BA365B3279ABF990@KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM Link: https://lkml.kernel.org/r/KL1P15301MB0006FA63BC22BEB64902EAA0BF930@KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM
2017-06-12tick/broadcast: Make tick_broadcast_setup_oneshot() staticStephen Boyd1-1/+3
This function isn't used outside of tick-broadcast.c, so let's mark it static. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Link: http://lkml.kernel.org/r/20170608063603.13276-1-sboyd@codeaurora.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-02-20Merge branch 'timers-core-for-linus' of ↵Linus Torvalds1-7/+8
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "Nothing exciting, just the usual pile of fixes, updates and cleanups: - A bunch of clocksource driver updates - Removal of CONFIG_TIMER_STATS and the related /proc file - More posix timer slim down work - A scalability enhancement in the tick broadcast code - Math cleanups" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) hrtimer: Catch invalid clockids again math64, tile: Fix build failure clocksource/drivers/arm_arch_timer:: Mark cyclecounter __ro_after_init timerfd: Protect the might cancel mechanism proper timer_list: Remove useless cast when printing time: Remove CONFIG_TIMER_STATS clocksource/drivers/arm_arch_timer: Work around Hisilicon erratum 161010101 clocksource/drivers/arm_arch_timer: Introduce generic errata handling infrastructure clocksource/drivers/arm_arch_timer: Remove fsl-a008585 parameter clocksource/drivers/arm_arch_timer: Add dt binding for hisilicon-161010101 erratum clocksource/drivers/ostm: Add renesas-ostm timer driver clocksource/drivers/ostm: Document renesas-ostm timer DT bindings clocksource/drivers/tcb_clksrc: Use 32 bit tcb as sched_clock clocksource/drivers/gemini: Add driver for the Cortina Gemini clocksource: add DT bindings for Cortina Gemini clockevents: Add a clkevt-of mechanism like clksrc-of tick/broadcast: Reduce lock cacheline contention timers: Omit POSIX timer stuff from task_struct when disabled x86/timer: Make delay() work during early bootup delay: Add explanation of udelay() inaccuracy ...
2017-02-13tick/broadcast: Prevent deadlock on tick_broadcast_lockMike Galbraith1-8/+7
tick_broadcast_lock is taken from interrupt context, but the following call chain takes the lock without disabling interrupts: [ 12.703736] _raw_spin_lock+0x3b/0x50 [ 12.703738] tick_broadcast_control+0x5a/0x1a0 [ 12.703742] intel_idle_cpu_online+0x22/0x100 [ 12.703744] cpuhp_invoke_callback+0x245/0x9d0 [ 12.703752] cpuhp_thread_fun+0x52/0x110 [ 12.703754] smpboot_thread_fn+0x276/0x320 So the following deadlock can happen: lock(tick_broadcast_lock); <Interrupt> lock(tick_broadcast_lock); intel_idle_cpu_online() is the only place which violates the calling convention of tick_broadcast_control(). This was caused by the removal of the smp function call in course of the cpu hotplug rework. Instead of slapping local_irq_disable/enable() at the call site, we can relax the calling convention and handle it in the core code, which makes the whole machinery more robust. Fixes: 29d7bbada98e ("intel_idle: Remove superfluous SMP fuction call") Reported-by: Gabriel C <nix.or.die@gmail.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Ruslan Ruslichenko <rruslich@cisco.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: lwn@lwn.net Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Anna-Maria Gleixner <anna-maria@linutronix.de> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: stable <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1486953115.5912.4.camel@gmx.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-02-04tick/broadcast: Reduce lock cacheline contentionWaiman Long1-7/+8
It was observed that on an Intel x86 system without the ARAT (Always running APIC timer) feature and with fairly large number of CPUs as well as CPUs coming in and out of intel_idle frequently, the lock contention on the tick_broadcast_lock can become significant. To reduce contention, the lock is put into its own cacheline and all the cpumask_var_t variables are put into the __read_mostly section. Running the SP benchmark of the NAS Parallel Benchmarks on a 4-socket 16-core 32-thread Nehalam system, the performance number improved from 3353.94 Mop/s to 3469.31 Mop/s when this patch was applied on a 4.9.6 kernel. This is a 3.4% improvement. Signed-off-by: Waiman Long <longman@redhat.com> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1485799063-20857-1-git-send-email-longman@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-25ktime: Get rid of the unionThomas Gleixner1-12/+12
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>
2016-12-15tick/broadcast: Prevent NULL pointer dereferenceThomas Gleixner1-0/+3
When a disfunctional timer, e.g. dummy timer, is installed, the tick core tries to setup the broadcast timer. If no broadcast device is installed, the kernel crashes with a NULL pointer dereference in tick_broadcast_setup_oneshot() because the function has no sanity check. Reported-by: Mason <slash.tmp@free.fr> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Anna-Maria Gleixner <anna-maria@linutronix.de> Cc: Richard Cochran <rcochran@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org>, Cc: Sebastian Frias <sf84@laposte.net> Cc: Thibaud Cornic <thibaud_cornic@sigmadesigns.com> Cc: Robin Murphy <robin.murphy@arm.com> Link: http://lkml.kernel.org/r/1147ef90-7877-e4d2-bb2b-5c4fa8d3144b@free.fr
2015-07-14tick: Move the export of tick_broadcast_oneshot_control to the proper placeThomas Gleixner1-1/+0
tick_broadcast_oneshot_control got moved from tick-broadcast to tick-common, but the export stayed in the old place. Fix it up. Fixes: f32dd1170511 'tick/broadcast: Make idle check independent from mode and config' Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-11tick/broadcast: Prevent NULL pointer dereferenceThomas Gleixner1-8/+10
Dan reported that the recent changes to the broadcast code introduced a potential NULL dereference. Add the proper check. Fixes: e0454311903d "tick/broadcast: Sanity check the shutdown of the local clock_event" Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-07tick/broadcast: Handle spurious interrupts gracefullyThomas Gleixner1-0/+7
Andriy reported that on a virtual machine the warning about negative expiry time in the clock events programming code triggered: hpet: hpet0 irq 40 for MSI hpet: hpet1 irq 41 for MSI Switching to clocksource hpet WARNING: at kernel/time/clockevents.c:239 [<ffffffff810ce6eb>] clockevents_program_event+0xdb/0xf0 [<ffffffff810cf211>] tick_handle_periodic_broadcast+0x41/0x50 [<ffffffff81016525>] timer_interrupt+0x15/0x20 When the second hpet is installed as a per cpu timer the broadcast event is not longer required and stopped, which sets the next_evt of the broadcast device to KTIME_MAX. If after that a spurious interrupt happens on the broadcast device, then the current code blindly handles it and tries to reprogram the broadcast device afterwards, which adds the period to next_evt. KTIME_MAX + period results in a negative expiry value causing the WARN_ON in the clockevents code to trigger. Add a proper check for the state of the broadcast device into the interrupt handler and return if the interrupt is spurious. [ Folded in pointer fix from Sudeep ] Reported-by: Andriy Gapon <avg@FreeBSD.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20150705205221.802094647@linutronix.de
2015-07-07tick/broadcast: Check for hrtimer broadcast active earlyThomas Gleixner1-10/+26
If the current cpu is the one which has the hrtimer based broadcast queued then we better return busy immediately instead of going through loops and hoops to figure that out. [ Split out from a larger combo patch ] Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Return busy when IPI is pendingThomas Gleixner1-3/+7
Tell the idle code not to go deep if the broadcast IPI is about to arrive. [ Split out from a larger combo patch ] Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Return busy if periodic mode and hrtimer broadcastThomas Gleixner1-1/+5
If the system is in periodic mode and the broadcast device is hrtimer based, return busy as we have no proper handling for this. [ Split out from a larger combo patch ] Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Move the check for periodic mode inside state handlingThomas Gleixner1-14/+8
We need to check more than the periodic mode for proper operation in all runtime combinations. To avoid code duplication move the check into the enter state handling. No functional change. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Prevent deep idle if no broadcast device availableThomas Gleixner1-0/+7
Add a check for a installed broadcast device to the oneshot control function and return busy if not. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Make idle check independent from mode and configThomas Gleixner1-15/+11
Currently the broadcast busy check, which prevents the idle code from going into deep idle, works only in one shot mode. If NOHZ and HIGHRES are off (config or command line) there is no sanity check at all, so under certain conditions cpus are allowed to go into deep idle, where the local timer stops, and are not woken up again because there is no broadcast timer installed or a hrtimer based broadcast device is not evaluated. Move tick_broadcast_oneshot_control() into the common code and provide proper subfunctions for the various config combinations. The common check in tick_broadcast_oneshot_control() is for the C3STOP misfeature flag of the local clock event device. If its not set, idle can proceed. If set, further checks are necessary. Provide checks for the trivial cases: - If broadcast is disabled in the config, then return busy - If oneshot mode (NOHZ/HIGHES) is disabled in the config, return busy if the broadcast device is hrtimer based. - If oneshot mode is enabled in the config call the original tick_broadcast_oneshot_control() function. That function needs extra checks which will be implemented in seperate patches. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Sanity check the shutdown of the local clock_eventThomas Gleixner1-7/+16
The broadcast code shuts down the local clock event unconditionally even if no broadcast device is installed or if the broadcast device is hrtimer based. Add proper sanity checks. [ Split out from a larger combo patch ] Reported-and-tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-07-07tick/broadcast: Prevent hrtimer recursionThomas Gleixner1-1/+15
The hrtimer based broadcast vehicle can cause a hrtimer recursion which went unnoticed until we changed the hrtimer expiry code to keep track of the currently running timer. local_timer_interrupt() local_handler() hrtimer_interrupt() expire_hrtimers() broadcast_hrtimer() send_ipis() local_handler() hrtimer_interrupt() .... Solution is simple: Prevent the local handler call from the broadcast code when the broadcast 'device' is hrtimer based. [ Split out from a larger combo patch ] Tested-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Suzuki Poulose <Suzuki.Poulose@arm.com> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> Cc: Catalin Marinas <Catalin.Marinas@arm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1507070929360.3916@nanos
2015-06-02clockevents: Provide functions to set and get the stateThomas Gleixner1-6/+6
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 Kumar1-3/+3
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>
2015-05-05tick: broadcast: Simplify oneshot logic and shorten lock regionThomas Gleixner1-25/+17
Simplify the oneshot logic by avoiding the reprogramming loops. That also allows to call the cpu local handler outside of the broadcast_lock held region. Tested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-05-05tick: broadcast: Prevent livelock from event handlerThomas Gleixner1-28/+25
With the removal of the hrtimer softirq the switch to highres/nohz mode happens in the tick interrupt. That leads to a livelock when the per cpu event handler is directly called from the broadcast handler under broadcast lock because broadcast lock needs to be taken for the highres/nohz switch as well. Solve this by calling the cpu local handler outside the broadcast_lock held region. Fixes: c6eb3f70d448 "hrtimer: Get rid of hrtimer softirq" Reported-and-tested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-04-03clockevents: Cleanup dead cpu explicitelyThomas Gleixner1-19/+20
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: Provide explicit broadcast oneshot control functionsThomas Gleixner1-11/+17
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: Provide explicit broadcast control functionsThomas Gleixner1-35/+27
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>
2015-04-02clockevents: Fix cpu_down() race for hrtimer based broadcastingPreeti U Murthy1-8/+11
It was found when doing a hotplug stress test on POWER, that the machine either hit softlockups or rcu_sched stall warnings. The issue was traced to commit: 7cba160ad789 ("powernv/cpuidle: Redesign idle states management") which exposed the cpu_down() race with hrtimer based broadcast mode: 5d1638acb9f6 ("tick: Introduce hrtimer based broadcast") The race is the following: Assume CPU1 is the CPU which holds the hrtimer broadcasting duty before it is taken down. CPU0 CPU1 cpu_down() take_cpu_down() disable_interrupts() cpu_die() while (CPU1 != CPU_DEAD) { msleep(100); switch_to_idle(); stop_cpu_timer(); schedule_broadcast(); } tick_cleanup_cpu_dead() take_over_broadcast() So after CPU1 disabled interrupts it cannot handle the broadcast hrtimer anymore, so CPU0 will be stuck forever. Fix this by explicitly taking over broadcast duty before cpu_die(). This is a temporary workaround. What we really want is a callback in the clockevent device which allows us to do that from the dying CPU by pushing the hrtimer onto a different cpu. That might involve an IPI and is definitely more complex than this immediate fix. Changelog was picked up from: https://lkml.org/lkml/2015/2/16/213 Suggested-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com> Cc: linuxppc-dev@lists.ozlabs.org Cc: mpe@ellerman.id.au Cc: nicolas.pitre@linaro.org Cc: peterz@infradead.org Cc: rjw@rjwysocki.net Fixes: http://linuxppc.10917.n7.nabble.com/offlining-cpus-breakage-td88619.html Link: http://lkml.kernel.org/r/20150330092410.24979.59887.stgit@preeti.in.ibm.com [ Merged it to the latest timer tree, renamed the callback, tidied up the changelog. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-01tick/xen: Provide and use tick_suspend_local() and tick_resume_local()Thomas Gleixner1-7/+17
Xen calls on every cpu into tick_resume() which is just wrong. tick_resume() is for the syscore global suspend/resume invocation. What XEN really wants is a per cpu local resume function. Provide a tick_resume_local() function and use it in XEN. Also provide a complementary tick_suspend_local() and modify tick_unfreeze() and tick_freeze(), respectively, to use the new local tick resume/suspend functions. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [ Combined two patches, rebased, modified subject/changelog. ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1698741.eezk9tnXtG@vostro.rjw.lan [ Merged to latest timers/core. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-01tick: Make tick_resume_broadcast_oneshot() staticThomas Gleixner1-3/+4
Solely used in tick-broadcast.c and the return value is hardcoded 0. Make it static and void. 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/1689058.QkHYDJSRKu@vostro.rjw.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27clockevents: Manage device's state separately for the coreViresh Kumar1-10/+10
'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 Kumar1-1/+1
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>
2014-08-26time: Replace __get_cpu_var usesChristoph Lameter1-1/+1
Convert uses of __get_cpu_var for creating a address from a percpu offset to this_cpu_ptr. The two cases where get_cpu_var is used to actually access a percpu variable are changed to use this_cpu_read/raw_cpu_read. Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-04-01Merge branch 'timers-core-for-linus' of ↵Linus Torvalds1-11/+74
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer changes from Thomas Gleixner: "This assorted collection provides: - A new timer based timer broadcast feature for systems which do not provide a global accessible timer device. That allows those systems to put CPUs into deep idle states where the per cpu timer device stops. - A few NOHZ_FULL related improvements to the timer wheel - The usual updates to timer devices found in ARM SoCs - Small improvements and updates all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits) tick: Remove code duplication in tick_handle_periodic() tick: Fix spelling mistake in tick_handle_periodic() x86: hpet: Use proper destructor for delayed work workqueue: Provide destroy_delayed_work_on_stack() clocksource: CMT, MTU2, TMU and STI should depend on GENERIC_CLOCKEVENTS timer: Remove code redundancy while calling get_nohz_timer_target() hrtimer: Rearrange comments in the order struct members are declared timer: Use variable head instead of &work_list in __run_timers() clocksource: exynos_mct: silence a static checker warning arm: zynq: Add support for cpufreq arm: zynq: Don't use arm_global_timer with cpufreq clocksource/cadence_ttc: Overhaul clocksource frequency adjustment clocksource/cadence_ttc: Call clockevents_update_freq() with IRQs enabled clocksource: Add Kconfig entries for CMT, MTU2, TMU and STI sh: Remove Kconfig entries for TMU, CMT and MTU2 ARM: shmobile: Remove CMT, TMU and STI Kconfig entries clocksource: armada-370-xp: Use atomic access for shared registers clocksource: orion: Use atomic access for shared registers clocksource: timer-keystone: Delete unnecessary variable clocksource: timer-keystone: introduce clocksource driver for Keystone ...
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