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Thomas Gleixner35728b82018-10-31 19:21:09 +01001// SPDX-License-Identifier: GPL-2.0
Thomas Gleixner906568c2007-02-16 01:28:01 -08002/*
Thomas Gleixner906568c2007-02-16 01:28:01 -08003 * This file contains the base functions to manage periodic tick
4 * related events.
5 *
6 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
7 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
8 * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
Thomas Gleixner906568c2007-02-16 01:28:01 -08009 */
10#include <linux/cpu.h>
11#include <linux/err.h>
12#include <linux/hrtimer.h>
Russell Kingd7b90682008-04-17 07:46:24 +020013#include <linux/interrupt.h>
Thomas Gleixner906568c2007-02-16 01:28:01 -080014#include <linux/percpu.h>
15#include <linux/profile.h>
16#include <linux/sched.h>
Thomas Gleixnerccf33d62013-04-25 20:31:49 +000017#include <linux/module.h>
Rafael J. Wysocki75e06782015-05-10 01:23:35 +020018#include <trace/events/power.h>
Thomas Gleixner906568c2007-02-16 01:28:01 -080019
Russell Kingd7b90682008-04-17 07:46:24 +020020#include <asm/irq_regs.h>
21
Thomas Gleixnerf8381cb2007-02-16 01:28:02 -080022#include "tick-internal.h"
23
Thomas Gleixner906568c2007-02-16 01:28:01 -080024/*
25 * Tick devices
26 */
Thomas Gleixnerf8381cb2007-02-16 01:28:02 -080027DEFINE_PER_CPU(struct tick_device, tick_cpu_device);
Thomas Gleixner906568c2007-02-16 01:28:01 -080028/*
29 * Tick next event: keeps track of the tick time
30 */
Thomas Gleixnerf8381cb2007-02-16 01:28:02 -080031ktime_t tick_next_period;
32ktime_t tick_period;
Andrew Morton050ded12013-11-15 14:15:33 -080033
34/*
35 * tick_do_timer_cpu is a timer core internal variable which holds the CPU NR
36 * which is responsible for calling do_timer(), i.e. the timekeeping stuff. This
37 * variable has two functions:
38 *
39 * 1) Prevent a thundering herd issue of a gazillion of CPUs trying to grab the
40 * timekeeping lock all at once. Only the CPU which is assigned to do the
41 * update is handling it.
42 *
43 * 2) Hand off the duty in the NOHZ idle case by setting the value to
44 * TICK_DO_TIMER_NONE, i.e. a non existing CPU. So the next cpu which looks
45 * at it will take over and keep the time keeping alive. The handover
46 * procedure also covers cpu hotplug.
47 */
Thomas Gleixner64414022008-09-22 18:46:37 +020048int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT;
Nicholas Piggin08ae95f2019-04-11 13:34:48 +100049#ifdef CONFIG_NO_HZ_FULL
50/*
51 * tick_do_timer_boot_cpu indicates the boot CPU temporarily owns
52 * tick_do_timer_cpu and it should be taken over by an eligible secondary
53 * when one comes online.
54 */
55static int tick_do_timer_boot_cpu __read_mostly = -1;
56#endif
Thomas Gleixner906568c2007-02-16 01:28:01 -080057
Ingo Molnar289f4802007-02-16 01:28:15 -080058/*
59 * Debugging: see timer_list.c
60 */
61struct tick_device *tick_get_device(int cpu)
62{
63 return &per_cpu(tick_cpu_device, cpu);
64}
65
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -080066/**
67 * tick_is_oneshot_available - check for a oneshot capable event device
68 */
69int tick_is_oneshot_available(void)
70{
Christoph Lameter909ea962010-12-08 16:22:55 +010071 struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -080072
Thomas Gleixner3a142a02011-02-25 22:34:23 +010073 if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT))
74 return 0;
75 if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
76 return 1;
77 return tick_broadcast_oneshot_available();
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -080078}
79
Thomas Gleixner906568c2007-02-16 01:28:01 -080080/*
81 * Periodic tick
82 */
83static void tick_periodic(int cpu)
84{
85 if (tick_do_timer_cpu == cpu) {
John Stultzd6ad4182012-02-28 16:50:11 -080086 write_seqlock(&jiffies_lock);
Thomas Gleixner906568c2007-02-16 01:28:01 -080087
88 /* Keep track of the next tick event */
89 tick_next_period = ktime_add(tick_next_period, tick_period);
90
91 do_timer(1);
John Stultzd6ad4182012-02-28 16:50:11 -080092 write_sequnlock(&jiffies_lock);
John Stultz47a1b7962013-12-12 13:10:55 -080093 update_wall_time();
Thomas Gleixner906568c2007-02-16 01:28:01 -080094 }
95
96 update_process_times(user_mode(get_irq_regs()));
97 profile_tick(CPU_PROFILING);
98}
99
100/*
101 * Event handler for periodic ticks
102 */
103void tick_handle_periodic(struct clock_event_device *dev)
104{
105 int cpu = smp_processor_id();
Viresh Kumarb97f0292014-03-25 13:56:23 +0530106 ktime_t next = dev->next_event;
Thomas Gleixner906568c2007-02-16 01:28:01 -0800107
108 tick_periodic(cpu);
109
Thomas Gleixnerc6eb3f72015-04-14 21:08:51 +0000110#if defined(CONFIG_HIGH_RES_TIMERS) || defined(CONFIG_NO_HZ_COMMON)
111 /*
112 * The cpu might have transitioned to HIGHRES or NOHZ mode via
113 * update_process_times() -> run_local_timers() ->
114 * hrtimer_run_queues().
115 */
116 if (dev->event_handler != tick_handle_periodic)
117 return;
118#endif
119
Viresh Kumar472c4a92015-05-21 13:33:46 +0530120 if (!clockevent_state_oneshot(dev))
Thomas Gleixner906568c2007-02-16 01:28:01 -0800121 return;
Thomas Gleixner906568c2007-02-16 01:28:01 -0800122 for (;;) {
Viresh Kumarb97f0292014-03-25 13:56:23 +0530123 /*
124 * Setup the next period for devices, which do not have
125 * periodic mode:
126 */
127 next = ktime_add(next, tick_period);
128
Martin Schwidefskyd1748302011-08-23 15:29:42 +0200129 if (!clockevents_program_event(dev, next, false))
Thomas Gleixner906568c2007-02-16 01:28:01 -0800130 return;
john stultz74a03b62009-05-01 13:10:25 -0700131 /*
132 * Have to be careful here. If we're in oneshot mode,
133 * before we call tick_periodic() in a loop, we need
134 * to be sure we're using a real hardware clocksource.
135 * Otherwise we could get trapped in an infinite
136 * loop, as the tick_periodic() increments jiffies,
Viresh Kumarcacb3c72014-03-25 16:09:18 +0530137 * which then will increment time, possibly causing
john stultz74a03b62009-05-01 13:10:25 -0700138 * the loop to trigger again and again.
139 */
140 if (timekeeping_valid_for_hres())
141 tick_periodic(cpu);
Thomas Gleixner906568c2007-02-16 01:28:01 -0800142 }
143}
144
145/*
146 * Setup the device for a periodic tick
147 */
Thomas Gleixnerf8381cb2007-02-16 01:28:02 -0800148void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
Thomas Gleixner906568c2007-02-16 01:28:01 -0800149{
Thomas Gleixnerf8381cb2007-02-16 01:28:02 -0800150 tick_set_periodic_handler(dev, broadcast);
151
152 /* Broadcast setup ? */
153 if (!tick_device_is_functional(dev))
154 return;
Thomas Gleixner906568c2007-02-16 01:28:01 -0800155
Thomas Gleixner27ce4cb2008-09-22 19:04:02 +0200156 if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) &&
157 !tick_broadcast_oneshot_active()) {
Thomas Gleixnerd7eb2312015-06-02 14:08:46 +0200158 clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC);
Thomas Gleixner906568c2007-02-16 01:28:01 -0800159 } else {
Rasmus Villemoese1e41b62019-03-18 20:55:56 +0100160 unsigned int seq;
Thomas Gleixner906568c2007-02-16 01:28:01 -0800161 ktime_t next;
162
163 do {
John Stultzd6ad4182012-02-28 16:50:11 -0800164 seq = read_seqbegin(&jiffies_lock);
Thomas Gleixner906568c2007-02-16 01:28:01 -0800165 next = tick_next_period;
John Stultzd6ad4182012-02-28 16:50:11 -0800166 } while (read_seqretry(&jiffies_lock, seq));
Thomas Gleixner906568c2007-02-16 01:28:01 -0800167
Thomas Gleixnerd7eb2312015-06-02 14:08:46 +0200168 clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
Thomas Gleixner906568c2007-02-16 01:28:01 -0800169
170 for (;;) {
Martin Schwidefskyd1748302011-08-23 15:29:42 +0200171 if (!clockevents_program_event(dev, next, false))
Thomas Gleixner906568c2007-02-16 01:28:01 -0800172 return;
173 next = ktime_add(next, tick_period);
174 }
175 }
176}
177
Nicholas Piggin08ae95f2019-04-11 13:34:48 +1000178#ifdef CONFIG_NO_HZ_FULL
179static void giveup_do_timer(void *info)
180{
181 int cpu = *(unsigned int *)info;
182
183 WARN_ON(tick_do_timer_cpu != smp_processor_id());
184
185 tick_do_timer_cpu = cpu;
186}
187
188static void tick_take_do_timer_from_boot(void)
189{
190 int cpu = smp_processor_id();
191 int from = tick_do_timer_boot_cpu;
192
193 if (from >= 0 && from != cpu)
194 smp_call_function_single(from, giveup_do_timer, &cpu, 1);
195}
196#endif
197
Thomas Gleixner906568c2007-02-16 01:28:01 -0800198/*
199 * Setup the tick device
200 */
201static void tick_setup_device(struct tick_device *td,
202 struct clock_event_device *newdev, int cpu,
Rusty Russell0de26522008-12-13 21:20:26 +1030203 const struct cpumask *cpumask)
Thomas Gleixner906568c2007-02-16 01:28:01 -0800204{
Thomas Gleixner906568c2007-02-16 01:28:01 -0800205 void (*handler)(struct clock_event_device *) = NULL;
Thomas Gleixner8b0e1952016-12-25 12:30:41 +0100206 ktime_t next_event = 0;
Thomas Gleixner906568c2007-02-16 01:28:01 -0800207
208 /*
209 * First device setup ?
210 */
211 if (!td->evtdev) {
212 /*
213 * If no cpu took the do_timer update, assign it to
214 * this cpu:
215 */
Thomas Gleixner64414022008-09-22 18:46:37 +0200216 if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
Nicholas Piggin08ae95f2019-04-11 13:34:48 +1000217 tick_do_timer_cpu = cpu;
218
Thomas Gleixner906568c2007-02-16 01:28:01 -0800219 tick_next_period = ktime_get();
Thomas Gleixner8b0e1952016-12-25 12:30:41 +0100220 tick_period = NSEC_PER_SEC / HZ;
Nicholas Piggin08ae95f2019-04-11 13:34:48 +1000221#ifdef CONFIG_NO_HZ_FULL
222 /*
223 * The boot CPU may be nohz_full, in which case set
224 * tick_do_timer_boot_cpu so the first housekeeping
225 * secondary that comes up will take do_timer from
226 * us.
227 */
228 if (tick_nohz_full_cpu(cpu))
229 tick_do_timer_boot_cpu = cpu;
230
231 } else if (tick_do_timer_boot_cpu != -1 &&
232 !tick_nohz_full_cpu(cpu)) {
233 tick_take_do_timer_from_boot();
234 tick_do_timer_boot_cpu = -1;
235 WARN_ON(tick_do_timer_cpu != cpu);
236#endif
Thomas Gleixner906568c2007-02-16 01:28:01 -0800237 }
238
239 /*
240 * Startup in periodic mode first.
241 */
242 td->mode = TICKDEV_MODE_PERIODIC;
243 } else {
244 handler = td->evtdev->event_handler;
245 next_event = td->evtdev->next_event;
Venkatesh Pallipadi7c1e7682008-09-03 21:36:50 +0000246 td->evtdev->event_handler = clockevents_handle_noop;
Thomas Gleixner906568c2007-02-16 01:28:01 -0800247 }
248
249 td->evtdev = newdev;
250
251 /*
252 * When the device is not per cpu, pin the interrupt to the
253 * current cpu:
254 */
Rusty Russell320ab2b2008-12-13 21:20:26 +1030255 if (!cpumask_equal(newdev->cpumask, cpumask))
Rusty Russell0de26522008-12-13 21:20:26 +1030256 irq_set_affinity(newdev->irq, cpumask);
Thomas Gleixner906568c2007-02-16 01:28:01 -0800257
Thomas Gleixnerf8381cb2007-02-16 01:28:02 -0800258 /*
259 * When global broadcasting is active, check if the current
260 * device is registered as a placeholder for broadcast mode.
261 * This allows us to handle this x86 misfeature in a generic
Thomas Gleixner07bd1172013-07-01 22:14:10 +0200262 * way. This function also returns !=0 when we keep the
263 * current active broadcast state for this CPU.
Thomas Gleixnerf8381cb2007-02-16 01:28:02 -0800264 */
265 if (tick_device_uses_broadcast(newdev, cpu))
266 return;
267
Thomas Gleixner906568c2007-02-16 01:28:01 -0800268 if (td->mode == TICKDEV_MODE_PERIODIC)
269 tick_setup_periodic(newdev, 0);
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -0800270 else
271 tick_setup_oneshot(newdev, handler, next_event);
Thomas Gleixner906568c2007-02-16 01:28:01 -0800272}
273
Thomas Gleixner03e13cf2013-04-25 20:31:50 +0000274void tick_install_replacement(struct clock_event_device *newdev)
275{
Christoph Lameter22127e92014-08-17 12:30:25 -0500276 struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
Thomas Gleixner03e13cf2013-04-25 20:31:50 +0000277 int cpu = smp_processor_id();
278
279 clockevents_exchange_device(td->evtdev, newdev);
280 tick_setup_device(td, newdev, cpu, cpumask_of(cpu));
281 if (newdev->features & CLOCK_EVT_FEAT_ONESHOT)
282 tick_oneshot_notify();
283}
284
Thomas Gleixner45cb8e02013-04-25 20:31:50 +0000285static bool tick_check_percpu(struct clock_event_device *curdev,
286 struct clock_event_device *newdev, int cpu)
287{
288 if (!cpumask_test_cpu(cpu, newdev->cpumask))
289 return false;
290 if (cpumask_equal(newdev->cpumask, cpumask_of(cpu)))
291 return true;
292 /* Check if irq affinity can be set */
293 if (newdev->irq >= 0 && !irq_can_set_affinity(newdev->irq))
294 return false;
295 /* Prefer an existing cpu local device */
296 if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu)))
297 return false;
298 return true;
299}
300
301static bool tick_check_preferred(struct clock_event_device *curdev,
302 struct clock_event_device *newdev)
303{
304 /* Prefer oneshot capable device */
305 if (!(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) {
306 if (curdev && (curdev->features & CLOCK_EVT_FEAT_ONESHOT))
307 return false;
308 if (tick_oneshot_mode_active())
309 return false;
310 }
311
Stephen Boyd70e59752013-06-13 11:39:50 -0700312 /*
313 * Use the higher rated one, but prefer a CPU local device with a lower
314 * rating than a non-CPU local device
315 */
316 return !curdev ||
317 newdev->rating > curdev->rating ||
Sudeep Holla5b5ccbc2018-07-09 16:45:35 +0100318 !cpumask_equal(curdev->cpumask, newdev->cpumask);
Thomas Gleixner45cb8e02013-04-25 20:31:50 +0000319}
320
Thomas Gleixner906568c2007-02-16 01:28:01 -0800321/*
Thomas Gleixner03e13cf2013-04-25 20:31:50 +0000322 * Check whether the new device is a better fit than curdev. curdev
323 * can be NULL !
324 */
325bool tick_check_replacement(struct clock_event_device *curdev,
326 struct clock_event_device *newdev)
327{
Viresh Kumar521c4292014-04-15 10:54:37 +0530328 if (!tick_check_percpu(curdev, newdev, smp_processor_id()))
Thomas Gleixner03e13cf2013-04-25 20:31:50 +0000329 return false;
330
331 return tick_check_preferred(curdev, newdev);
332}
333
334/*
Thomas Gleixner7126cac2013-04-25 20:31:48 +0000335 * Check, if the new registered device should be used. Called with
336 * clockevents_lock held and interrupts disabled.
Thomas Gleixner906568c2007-02-16 01:28:01 -0800337 */
Thomas Gleixner7172a2862013-04-25 20:31:47 +0000338void tick_check_new_device(struct clock_event_device *newdev)
Thomas Gleixner906568c2007-02-16 01:28:01 -0800339{
340 struct clock_event_device *curdev;
341 struct tick_device *td;
Thomas Gleixner7172a2862013-04-25 20:31:47 +0000342 int cpu;
Thomas Gleixner906568c2007-02-16 01:28:01 -0800343
344 cpu = smp_processor_id();
Thomas Gleixner906568c2007-02-16 01:28:01 -0800345 td = &per_cpu(tick_cpu_device, cpu);
346 curdev = td->evtdev;
Thomas Gleixner906568c2007-02-16 01:28:01 -0800347
348 /* cpu local device ? */
Thomas Gleixner45cb8e02013-04-25 20:31:50 +0000349 if (!tick_check_percpu(curdev, newdev, cpu))
350 goto out_bc;
Thomas Gleixner906568c2007-02-16 01:28:01 -0800351
Thomas Gleixner45cb8e02013-04-25 20:31:50 +0000352 /* Preference decision */
353 if (!tick_check_preferred(curdev, newdev))
354 goto out_bc;
Thomas Gleixner906568c2007-02-16 01:28:01 -0800355
Thomas Gleixnerccf33d62013-04-25 20:31:49 +0000356 if (!try_module_get(newdev->owner))
357 return;
358
Thomas Gleixner906568c2007-02-16 01:28:01 -0800359 /*
360 * Replace the eventually existing device by the new
Thomas Gleixnerf8381cb2007-02-16 01:28:02 -0800361 * device. If the current device is the broadcast device, do
362 * not give it back to the clockevents layer !
Thomas Gleixner906568c2007-02-16 01:28:01 -0800363 */
Thomas Gleixnerf8381cb2007-02-16 01:28:02 -0800364 if (tick_is_broadcast_device(curdev)) {
Thomas Gleixner2344abb2008-09-16 11:32:50 -0700365 clockevents_shutdown(curdev);
Thomas Gleixnerf8381cb2007-02-16 01:28:02 -0800366 curdev = NULL;
367 }
Thomas Gleixner906568c2007-02-16 01:28:01 -0800368 clockevents_exchange_device(curdev, newdev);
Rusty Russell6b954822009-01-01 10:12:25 +1030369 tick_setup_device(td, newdev, cpu, cpumask_of(cpu));
Thomas Gleixner79bf2bb2007-02-16 01:28:03 -0800370 if (newdev->features & CLOCK_EVT_FEAT_ONESHOT)
371 tick_oneshot_notify();
Thomas Gleixner7172a2862013-04-25 20:31:47 +0000372 return;
Thomas Gleixnerf8381cb2007-02-16 01:28:02 -0800373
374out_bc:
375 /*
376 * Can the new device be used as a broadcast device ?
377 */
Thomas Gleixner7172a2862013-04-25 20:31:47 +0000378 tick_install_broadcast_device(newdev);
Thomas Gleixner906568c2007-02-16 01:28:01 -0800379}
380
Thomas Gleixnerf32dd112015-07-07 16:29:38 +0200381/**
382 * tick_broadcast_oneshot_control - Enter/exit broadcast oneshot mode
383 * @state: The target state (enter/exit)
384 *
385 * The system enters/leaves a state, where affected devices might stop
386 * Returns 0 on success, -EBUSY if the cpu is used to broadcast wakeups.
387 *
388 * Called with interrupts disabled, so clockevents_lock is not
389 * required here because the local clock event device cannot go away
390 * under us.
391 */
392int tick_broadcast_oneshot_control(enum tick_broadcast_state state)
393{
394 struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
395
396 if (!(td->evtdev->features & CLOCK_EVT_FEAT_C3STOP))
397 return 0;
398
399 return __tick_broadcast_oneshot_control(state);
400}
Thomas Gleixner0f447052015-07-14 12:01:04 +0200401EXPORT_SYMBOL_GPL(tick_broadcast_oneshot_control);
Thomas Gleixnerf32dd112015-07-07 16:29:38 +0200402
Thomas Gleixner52c063d2015-04-03 02:37:24 +0200403#ifdef CONFIG_HOTPLUG_CPU
Thomas Gleixner906568c2007-02-16 01:28:01 -0800404/*
Sebastien Dugue94df7de2008-12-01 14:09:07 +0100405 * Transfer the do_timer job away from a dying cpu.
406 *
Thomas Gleixner52c063d2015-04-03 02:37:24 +0200407 * Called with interrupts disabled. Not locking required. If
408 * tick_do_timer_cpu is owned by this cpu, nothing can change it.
Sebastien Dugue94df7de2008-12-01 14:09:07 +0100409 */
Thomas Gleixner52c063d2015-04-03 02:37:24 +0200410void tick_handover_do_timer(void)
Sebastien Dugue94df7de2008-12-01 14:09:07 +0100411{
Thomas Gleixner52c063d2015-04-03 02:37:24 +0200412 if (tick_do_timer_cpu == smp_processor_id()) {
Sebastien Dugue94df7de2008-12-01 14:09:07 +0100413 int cpu = cpumask_first(cpu_online_mask);
414
415 tick_do_timer_cpu = (cpu < nr_cpu_ids) ? cpu :
416 TICK_DO_TIMER_NONE;
417 }
418}
419
420/*
Thomas Gleixner906568c2007-02-16 01:28:01 -0800421 * Shutdown an event device on a given cpu:
422 *
423 * This is called on a life CPU, when a CPU is dead. So we cannot
424 * access the hardware device itself.
425 * We just set the mode and remove it from the lists.
426 */
Thomas Gleixnera49b1162015-04-03 02:38:05 +0200427void tick_shutdown(unsigned int cpu)
Thomas Gleixner906568c2007-02-16 01:28:01 -0800428{
Thomas Gleixnera49b1162015-04-03 02:38:05 +0200429 struct tick_device *td = &per_cpu(tick_cpu_device, cpu);
Thomas Gleixner906568c2007-02-16 01:28:01 -0800430 struct clock_event_device *dev = td->evtdev;
Thomas Gleixner906568c2007-02-16 01:28:01 -0800431
Thomas Gleixner906568c2007-02-16 01:28:01 -0800432 td->mode = TICKDEV_MODE_PERIODIC;
433 if (dev) {
434 /*
435 * Prevent that the clock events layer tries to call
436 * the set mode function!
437 */
Thomas Gleixner051ebd12015-06-02 14:13:46 +0200438 clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED);
Thomas Gleixner906568c2007-02-16 01:28:01 -0800439 clockevents_exchange_device(dev, NULL);
Thomas Gleixner6f7a05d2013-04-25 11:45:53 +0200440 dev->event_handler = clockevents_handle_noop;
Thomas Gleixner906568c2007-02-16 01:28:01 -0800441 td->evtdev = NULL;
442 }
Thomas Gleixner906568c2007-02-16 01:28:01 -0800443}
Thomas Gleixnera49b1162015-04-03 02:38:05 +0200444#endif
Thomas Gleixner906568c2007-02-16 01:28:01 -0800445
Thomas Gleixner4ffee522015-03-25 13:09:16 +0100446/**
Thomas Gleixnerf46481d2015-03-25 13:11:04 +0100447 * tick_suspend_local - Suspend the local tick device
448 *
449 * Called from the local cpu for freeze with interrupts disabled.
450 *
451 * No locks required. Nothing can change the per cpu device.
452 */
Thomas Gleixner7270d112015-03-25 13:11:52 +0100453void tick_suspend_local(void)
Thomas Gleixnerf46481d2015-03-25 13:11:04 +0100454{
455 struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
456
457 clockevents_shutdown(td->evtdev);
458}
459
460/**
461 * tick_resume_local - Resume the local tick device
462 *
463 * Called from the local CPU for unfreeze or XEN resume magic.
464 *
465 * No locks required. Nothing can change the per cpu device.
466 */
467void tick_resume_local(void)
468{
469 struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
470 bool broadcast = tick_resume_check_broadcast();
471
472 clockevents_tick_resume(td->evtdev);
473 if (!broadcast) {
474 if (td->mode == TICKDEV_MODE_PERIODIC)
475 tick_setup_periodic(td->evtdev, 0);
476 else
477 tick_resume_oneshot();
478 }
479}
480
481/**
Thomas Gleixner4ffee522015-03-25 13:09:16 +0100482 * tick_suspend - Suspend the tick and the broadcast device
483 *
484 * Called from syscore_suspend() via timekeeping_suspend with only one
485 * CPU online and interrupts disabled or from tick_unfreeze() under
486 * tick_freeze_lock.
487 *
488 * No locks required. Nothing can change the per cpu device.
489 */
Thomas Gleixner8c53daf2013-04-25 20:31:48 +0000490void tick_suspend(void)
Thomas Gleixner6321dd62007-03-06 08:25:42 +0100491{
Thomas Gleixnerf46481d2015-03-25 13:11:04 +0100492 tick_suspend_local();
Thomas Gleixner4ffee522015-03-25 13:09:16 +0100493 tick_suspend_broadcast();
Thomas Gleixner6321dd62007-03-06 08:25:42 +0100494}
495
Thomas Gleixner4ffee522015-03-25 13:09:16 +0100496/**
497 * tick_resume - Resume the tick and the broadcast device
498 *
499 * Called from syscore_resume() via timekeeping_resume with only one
Thomas Gleixnerf46481d2015-03-25 13:11:04 +0100500 * CPU online and interrupts disabled.
Thomas Gleixner4ffee522015-03-25 13:09:16 +0100501 *
502 * No locks required. Nothing can change the per cpu device.
503 */
Thomas Gleixner8c53daf2013-04-25 20:31:48 +0000504void tick_resume(void)
Thomas Gleixner6321dd62007-03-06 08:25:42 +0100505{
Thomas Gleixnerf46481d2015-03-25 13:11:04 +0100506 tick_resume_broadcast();
507 tick_resume_local();
Thomas Gleixner6321dd62007-03-06 08:25:42 +0100508}
509
Rafael J. Wysocki87e9b9f2015-05-16 01:38:15 +0200510#ifdef CONFIG_SUSPEND
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100511static DEFINE_RAW_SPINLOCK(tick_freeze_lock);
512static unsigned int tick_freeze_depth;
513
514/**
515 * tick_freeze - Suspend the local tick and (possibly) timekeeping.
516 *
517 * Check if this is the last online CPU executing the function and if so,
518 * suspend timekeeping. Otherwise suspend the local tick.
519 *
520 * Call with interrupts disabled. Must be balanced with %tick_unfreeze().
521 * Interrupts must not be enabled before the subsequent %tick_unfreeze().
522 */
523void tick_freeze(void)
524{
525 raw_spin_lock(&tick_freeze_lock);
526
527 tick_freeze_depth++;
Rafael J. Wysocki75e06782015-05-10 01:23:35 +0200528 if (tick_freeze_depth == num_online_cpus()) {
529 trace_suspend_resume(TPS("timekeeping_freeze"),
530 smp_processor_id(), true);
Thomas Gleixnerc1a957d2018-05-25 17:54:41 +0200531 system_state = SYSTEM_SUSPEND;
Chang-An Chen3f2552f2019-03-29 10:59:09 +0800532 sched_clock_suspend();
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100533 timekeeping_suspend();
Rafael J. Wysocki75e06782015-05-10 01:23:35 +0200534 } else {
Thomas Gleixnerf46481d2015-03-25 13:11:04 +0100535 tick_suspend_local();
Rafael J. Wysocki75e06782015-05-10 01:23:35 +0200536 }
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100537
538 raw_spin_unlock(&tick_freeze_lock);
539}
540
541/**
542 * tick_unfreeze - Resume the local tick and (possibly) timekeeping.
543 *
544 * Check if this is the first CPU executing the function and if so, resume
545 * timekeeping. Otherwise resume the local tick.
546 *
547 * Call with interrupts disabled. Must be balanced with %tick_freeze().
548 * Interrupts must not be enabled after the preceding %tick_freeze().
549 */
550void tick_unfreeze(void)
551{
552 raw_spin_lock(&tick_freeze_lock);
553
Rafael J. Wysocki75e06782015-05-10 01:23:35 +0200554 if (tick_freeze_depth == num_online_cpus()) {
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100555 timekeeping_resume();
Chang-An Chen3f2552f2019-03-29 10:59:09 +0800556 sched_clock_resume();
Thomas Gleixnerc1a957d2018-05-25 17:54:41 +0200557 system_state = SYSTEM_RUNNING;
Rafael J. Wysocki75e06782015-05-10 01:23:35 +0200558 trace_suspend_resume(TPS("timekeeping_freeze"),
559 smp_processor_id(), false);
560 } else {
Rafael J. Wysocki422fe752015-04-03 15:21:51 +0200561 tick_resume_local();
Rafael J. Wysocki75e06782015-05-10 01:23:35 +0200562 }
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100563
564 tick_freeze_depth--;
565
566 raw_spin_unlock(&tick_freeze_lock);
567}
Rafael J. Wysocki87e9b9f2015-05-16 01:38:15 +0200568#endif /* CONFIG_SUSPEND */
Rafael J. Wysocki124cf9112015-02-13 23:50:43 +0100569
Thomas Gleixner906568c2007-02-16 01:28:01 -0800570/**
571 * tick_init - initialize the tick control
Thomas Gleixner906568c2007-02-16 01:28:01 -0800572 */
573void __init tick_init(void)
574{
Thomas Gleixnerb352bc12013-03-05 14:25:32 +0100575 tick_broadcast_init();
Frederic Weisbeckera80e49e2014-08-16 17:47:18 +0200576 tick_nohz_init();
Thomas Gleixner906568c2007-02-16 01:28:01 -0800577}