Commit | Line | Data |
---|---|---|
35728b82 | 1 | // SPDX-License-Identifier: GPL-2.0 |
906568c9 | 2 | /* |
906568c9 TG |
3 | * 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 | |
906568c9 | 9 | */ |
f87cbcb3 | 10 | #include <linux/compiler.h> |
906568c9 TG |
11 | #include <linux/cpu.h> |
12 | #include <linux/err.h> | |
13 | #include <linux/hrtimer.h> | |
d7b90689 | 14 | #include <linux/interrupt.h> |
5167c506 | 15 | #include <linux/nmi.h> |
906568c9 TG |
16 | #include <linux/percpu.h> |
17 | #include <linux/profile.h> | |
18 | #include <linux/sched.h> | |
ccf33d68 | 19 | #include <linux/module.h> |
75e0678e | 20 | #include <trace/events/power.h> |
906568c9 | 21 | |
d7b90689 RK |
22 | #include <asm/irq_regs.h> |
23 | ||
f8381cba TG |
24 | #include "tick-internal.h" |
25 | ||
906568c9 TG |
26 | /* |
27 | * Tick devices | |
28 | */ | |
f8381cba | 29 | DEFINE_PER_CPU(struct tick_device, tick_cpu_device); |
906568c9 | 30 | /* |
c398960c TG |
31 | * Tick next event: keeps track of the tick time. It's updated by the |
32 | * CPU which handles the tick and protected by jiffies_lock. There is | |
33 | * no requirement to write hold the jiffies seqcount for it. | |
906568c9 | 34 | */ |
f8381cba | 35 | ktime_t tick_next_period; |
050ded1b AM |
36 | |
37 | /* | |
38 | * tick_do_timer_cpu is a timer core internal variable which holds the CPU NR | |
39 | * which is responsible for calling do_timer(), i.e. the timekeeping stuff. This | |
40 | * variable has two functions: | |
41 | * | |
42 | * 1) Prevent a thundering herd issue of a gazillion of CPUs trying to grab the | |
43 | * timekeeping lock all at once. Only the CPU which is assigned to do the | |
44 | * update is handling it. | |
45 | * | |
46 | * 2) Hand off the duty in the NOHZ idle case by setting the value to | |
47 | * TICK_DO_TIMER_NONE, i.e. a non existing CPU. So the next cpu which looks | |
48 | * at it will take over and keep the time keeping alive. The handover | |
49 | * procedure also covers cpu hotplug. | |
50 | */ | |
6441402b | 51 | int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT; |
08ae95f4 NP |
52 | #ifdef CONFIG_NO_HZ_FULL |
53 | /* | |
54 | * tick_do_timer_boot_cpu indicates the boot CPU temporarily owns | |
55 | * tick_do_timer_cpu and it should be taken over by an eligible secondary | |
56 | * when one comes online. | |
57 | */ | |
58 | static int tick_do_timer_boot_cpu __read_mostly = -1; | |
59 | #endif | |
906568c9 | 60 | |
289f480a IM |
61 | /* |
62 | * Debugging: see timer_list.c | |
63 | */ | |
64 | struct tick_device *tick_get_device(int cpu) | |
65 | { | |
66 | return &per_cpu(tick_cpu_device, cpu); | |
67 | } | |
68 | ||
79bf2bb3 TG |
69 | /** |
70 | * tick_is_oneshot_available - check for a oneshot capable event device | |
71 | */ | |
72 | int tick_is_oneshot_available(void) | |
73 | { | |
909ea964 | 74 | struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev); |
79bf2bb3 | 75 | |
3a142a06 TG |
76 | if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT)) |
77 | return 0; | |
78 | if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) | |
79 | return 1; | |
80 | return tick_broadcast_oneshot_available(); | |
79bf2bb3 TG |
81 | } |
82 | ||
906568c9 TG |
83 | /* |
84 | * Periodic tick | |
85 | */ | |
86 | static void tick_periodic(int cpu) | |
87 | { | |
f87cbcb3 | 88 | if (READ_ONCE(tick_do_timer_cpu) == cpu) { |
e5d4d175 TG |
89 | raw_spin_lock(&jiffies_lock); |
90 | write_seqcount_begin(&jiffies_seq); | |
906568c9 TG |
91 | |
92 | /* Keep track of the next tick event */ | |
b9965449 | 93 | tick_next_period = ktime_add_ns(tick_next_period, TICK_NSEC); |
906568c9 TG |
94 | |
95 | do_timer(1); | |
e5d4d175 TG |
96 | write_seqcount_end(&jiffies_seq); |
97 | raw_spin_unlock(&jiffies_lock); | |
47a1b796 | 98 | update_wall_time(); |
906568c9 TG |
99 | } |
100 | ||
101 | update_process_times(user_mode(get_irq_regs())); | |
102 | profile_tick(CPU_PROFILING); | |
103 | } | |
104 | ||
105 | /* | |
106 | * Event handler for periodic ticks | |
107 | */ | |
108 | void tick_handle_periodic(struct clock_event_device *dev) | |
109 | { | |
110 | int cpu = smp_processor_id(); | |
b97f0291 | 111 | ktime_t next = dev->next_event; |
906568c9 TG |
112 | |
113 | tick_periodic(cpu); | |
114 | ||
c6eb3f70 TG |
115 | /* |
116 | * The cpu might have transitioned to HIGHRES or NOHZ mode via | |
117 | * update_process_times() -> run_local_timers() -> | |
118 | * hrtimer_run_queues(). | |
119 | */ | |
27dc0809 | 120 | if (IS_ENABLED(CONFIG_TICK_ONESHOT) && dev->event_handler != tick_handle_periodic) |
c6eb3f70 | 121 | return; |
c6eb3f70 | 122 | |
472c4a94 | 123 | if (!clockevent_state_oneshot(dev)) |
906568c9 | 124 | return; |
906568c9 | 125 | for (;;) { |
b97f0291 VK |
126 | /* |
127 | * Setup the next period for devices, which do not have | |
128 | * periodic mode: | |
129 | */ | |
b9965449 | 130 | next = ktime_add_ns(next, TICK_NSEC); |
b97f0291 | 131 | |
d1748302 | 132 | if (!clockevents_program_event(dev, next, false)) |
906568c9 | 133 | return; |
74a03b69 | 134 | /* |
135 | * Have to be careful here. If we're in oneshot mode, | |
136 | * before we call tick_periodic() in a loop, we need | |
137 | * to be sure we're using a real hardware clocksource. | |
138 | * Otherwise we could get trapped in an infinite | |
139 | * loop, as the tick_periodic() increments jiffies, | |
cacb3c76 | 140 | * which then will increment time, possibly causing |
74a03b69 | 141 | * the loop to trigger again and again. |
142 | */ | |
143 | if (timekeeping_valid_for_hres()) | |
144 | tick_periodic(cpu); | |
906568c9 TG |
145 | } |
146 | } | |
147 | ||
148 | /* | |
149 | * Setup the device for a periodic tick | |
150 | */ | |
f8381cba | 151 | void tick_setup_periodic(struct clock_event_device *dev, int broadcast) |
906568c9 | 152 | { |
f8381cba TG |
153 | tick_set_periodic_handler(dev, broadcast); |
154 | ||
155 | /* Broadcast setup ? */ | |
156 | if (!tick_device_is_functional(dev)) | |
157 | return; | |
906568c9 | 158 | |
27ce4cb4 TG |
159 | if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) && |
160 | !tick_broadcast_oneshot_active()) { | |
d7eb231c | 161 | clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC); |
906568c9 | 162 | } else { |
e1e41b6c | 163 | unsigned int seq; |
906568c9 TG |
164 | ktime_t next; |
165 | ||
166 | do { | |
e5d4d175 | 167 | seq = read_seqcount_begin(&jiffies_seq); |
906568c9 | 168 | next = tick_next_period; |
e5d4d175 | 169 | } while (read_seqcount_retry(&jiffies_seq, seq)); |
906568c9 | 170 | |
d7eb231c | 171 | clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT); |
906568c9 TG |
172 | |
173 | for (;;) { | |
d1748302 | 174 | if (!clockevents_program_event(dev, next, false)) |
906568c9 | 175 | return; |
b9965449 | 176 | next = ktime_add_ns(next, TICK_NSEC); |
906568c9 TG |
177 | } |
178 | } | |
179 | } | |
180 | ||
08ae95f4 NP |
181 | #ifdef CONFIG_NO_HZ_FULL |
182 | static void giveup_do_timer(void *info) | |
183 | { | |
184 | int cpu = *(unsigned int *)info; | |
185 | ||
186 | WARN_ON(tick_do_timer_cpu != smp_processor_id()); | |
187 | ||
188 | tick_do_timer_cpu = cpu; | |
189 | } | |
190 | ||
191 | static void tick_take_do_timer_from_boot(void) | |
192 | { | |
193 | int cpu = smp_processor_id(); | |
194 | int from = tick_do_timer_boot_cpu; | |
195 | ||
196 | if (from >= 0 && from != cpu) | |
197 | smp_call_function_single(from, giveup_do_timer, &cpu, 1); | |
198 | } | |
199 | #endif | |
200 | ||
906568c9 TG |
201 | /* |
202 | * Setup the tick device | |
203 | */ | |
204 | static void tick_setup_device(struct tick_device *td, | |
205 | struct clock_event_device *newdev, int cpu, | |
0de26520 | 206 | const struct cpumask *cpumask) |
906568c9 | 207 | { |
906568c9 | 208 | void (*handler)(struct clock_event_device *) = NULL; |
8b0e1953 | 209 | ktime_t next_event = 0; |
906568c9 TG |
210 | |
211 | /* | |
212 | * First device setup ? | |
213 | */ | |
214 | if (!td->evtdev) { | |
215 | /* | |
216 | * If no cpu took the do_timer update, assign it to | |
217 | * this cpu: | |
218 | */ | |
f87cbcb3 TG |
219 | if (READ_ONCE(tick_do_timer_cpu) == TICK_DO_TIMER_BOOT) { |
220 | WRITE_ONCE(tick_do_timer_cpu, cpu); | |
13bb06f8 | 221 | tick_next_period = ktime_get(); |
08ae95f4 NP |
222 | #ifdef CONFIG_NO_HZ_FULL |
223 | /* | |
224 | * The boot CPU may be nohz_full, in which case set | |
225 | * tick_do_timer_boot_cpu so the first housekeeping | |
226 | * secondary that comes up will take do_timer from | |
227 | * us. | |
228 | */ | |
229 | if (tick_nohz_full_cpu(cpu)) | |
230 | tick_do_timer_boot_cpu = cpu; | |
231 | ||
232 | } else if (tick_do_timer_boot_cpu != -1 && | |
233 | !tick_nohz_full_cpu(cpu)) { | |
234 | tick_take_do_timer_from_boot(); | |
235 | tick_do_timer_boot_cpu = -1; | |
f87cbcb3 | 236 | WARN_ON(READ_ONCE(tick_do_timer_cpu) != cpu); |
08ae95f4 | 237 | #endif |
906568c9 TG |
238 | } |
239 | ||
240 | /* | |
241 | * Startup in periodic mode first. | |
242 | */ | |
243 | td->mode = TICKDEV_MODE_PERIODIC; | |
244 | } else { | |
245 | handler = td->evtdev->event_handler; | |
246 | next_event = td->evtdev->next_event; | |
7c1e7689 | 247 | td->evtdev->event_handler = clockevents_handle_noop; |
906568c9 TG |
248 | } |
249 | ||
250 | td->evtdev = newdev; | |
251 | ||
252 | /* | |
253 | * When the device is not per cpu, pin the interrupt to the | |
254 | * current cpu: | |
255 | */ | |
320ab2b0 | 256 | if (!cpumask_equal(newdev->cpumask, cpumask)) |
0de26520 | 257 | irq_set_affinity(newdev->irq, cpumask); |
906568c9 | 258 | |
f8381cba TG |
259 | /* |
260 | * When global broadcasting is active, check if the current | |
261 | * device is registered as a placeholder for broadcast mode. | |
262 | * This allows us to handle this x86 misfeature in a generic | |
07bd1172 TG |
263 | * way. This function also returns !=0 when we keep the |
264 | * current active broadcast state for this CPU. | |
f8381cba TG |
265 | */ |
266 | if (tick_device_uses_broadcast(newdev, cpu)) | |
267 | return; | |
268 | ||
906568c9 TG |
269 | if (td->mode == TICKDEV_MODE_PERIODIC) |
270 | tick_setup_periodic(newdev, 0); | |
79bf2bb3 TG |
271 | else |
272 | tick_setup_oneshot(newdev, handler, next_event); | |
906568c9 TG |
273 | } |
274 | ||
03e13cf5 TG |
275 | void tick_install_replacement(struct clock_event_device *newdev) |
276 | { | |
22127e93 | 277 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
03e13cf5 TG |
278 | int cpu = smp_processor_id(); |
279 | ||
280 | clockevents_exchange_device(td->evtdev, newdev); | |
281 | tick_setup_device(td, newdev, cpu, cpumask_of(cpu)); | |
282 | if (newdev->features & CLOCK_EVT_FEAT_ONESHOT) | |
283 | tick_oneshot_notify(); | |
284 | } | |
285 | ||
45cb8e01 TG |
286 | static bool tick_check_percpu(struct clock_event_device *curdev, |
287 | struct clock_event_device *newdev, int cpu) | |
288 | { | |
289 | if (!cpumask_test_cpu(cpu, newdev->cpumask)) | |
290 | return false; | |
291 | if (cpumask_equal(newdev->cpumask, cpumask_of(cpu))) | |
292 | return true; | |
293 | /* Check if irq affinity can be set */ | |
294 | if (newdev->irq >= 0 && !irq_can_set_affinity(newdev->irq)) | |
295 | return false; | |
296 | /* Prefer an existing cpu local device */ | |
297 | if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu))) | |
298 | return false; | |
299 | return true; | |
300 | } | |
301 | ||
302 | static bool tick_check_preferred(struct clock_event_device *curdev, | |
303 | struct clock_event_device *newdev) | |
304 | { | |
305 | /* Prefer oneshot capable device */ | |
306 | if (!(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) { | |
307 | if (curdev && (curdev->features & CLOCK_EVT_FEAT_ONESHOT)) | |
308 | return false; | |
309 | if (tick_oneshot_mode_active()) | |
310 | return false; | |
311 | } | |
312 | ||
70e5975d SB |
313 | /* |
314 | * Use the higher rated one, but prefer a CPU local device with a lower | |
315 | * rating than a non-CPU local device | |
316 | */ | |
317 | return !curdev || | |
318 | newdev->rating > curdev->rating || | |
5b5ccbc2 | 319 | !cpumask_equal(curdev->cpumask, newdev->cpumask); |
45cb8e01 TG |
320 | } |
321 | ||
03e13cf5 TG |
322 | /* |
323 | * Check whether the new device is a better fit than curdev. curdev | |
324 | * can be NULL ! | |
325 | */ | |
326 | bool tick_check_replacement(struct clock_event_device *curdev, | |
327 | struct clock_event_device *newdev) | |
328 | { | |
521c4299 | 329 | if (!tick_check_percpu(curdev, newdev, smp_processor_id())) |
03e13cf5 TG |
330 | return false; |
331 | ||
332 | return tick_check_preferred(curdev, newdev); | |
333 | } | |
334 | ||
906568c9 | 335 | /* |
7126cac4 TG |
336 | * Check, if the new registered device should be used. Called with |
337 | * clockevents_lock held and interrupts disabled. | |
906568c9 | 338 | */ |
7172a286 | 339 | void tick_check_new_device(struct clock_event_device *newdev) |
906568c9 TG |
340 | { |
341 | struct clock_event_device *curdev; | |
342 | struct tick_device *td; | |
7172a286 | 343 | int cpu; |
906568c9 TG |
344 | |
345 | cpu = smp_processor_id(); | |
906568c9 TG |
346 | td = &per_cpu(tick_cpu_device, cpu); |
347 | curdev = td->evtdev; | |
906568c9 | 348 | |
d7840aaa | 349 | if (!tick_check_replacement(curdev, newdev)) |
45cb8e01 | 350 | goto out_bc; |
906568c9 | 351 | |
ccf33d68 TG |
352 | if (!try_module_get(newdev->owner)) |
353 | return; | |
354 | ||
906568c9 TG |
355 | /* |
356 | * Replace the eventually existing device by the new | |
f8381cba TG |
357 | * device. If the current device is the broadcast device, do |
358 | * not give it back to the clockevents layer ! | |
906568c9 | 359 | */ |
f8381cba | 360 | if (tick_is_broadcast_device(curdev)) { |
2344abbc | 361 | clockevents_shutdown(curdev); |
f8381cba TG |
362 | curdev = NULL; |
363 | } | |
906568c9 | 364 | clockevents_exchange_device(curdev, newdev); |
6b954823 | 365 | tick_setup_device(td, newdev, cpu, cpumask_of(cpu)); |
79bf2bb3 TG |
366 | if (newdev->features & CLOCK_EVT_FEAT_ONESHOT) |
367 | tick_oneshot_notify(); | |
7172a286 | 368 | return; |
f8381cba TG |
369 | |
370 | out_bc: | |
371 | /* | |
372 | * Can the new device be used as a broadcast device ? | |
373 | */ | |
c94a8537 | 374 | tick_install_broadcast_device(newdev, cpu); |
906568c9 TG |
375 | } |
376 | ||
f32dd117 TG |
377 | /** |
378 | * tick_broadcast_oneshot_control - Enter/exit broadcast oneshot mode | |
379 | * @state: The target state (enter/exit) | |
380 | * | |
381 | * The system enters/leaves a state, where affected devices might stop | |
382 | * Returns 0 on success, -EBUSY if the cpu is used to broadcast wakeups. | |
383 | * | |
384 | * Called with interrupts disabled, so clockevents_lock is not | |
385 | * required here because the local clock event device cannot go away | |
386 | * under us. | |
387 | */ | |
388 | int tick_broadcast_oneshot_control(enum tick_broadcast_state state) | |
389 | { | |
390 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); | |
391 | ||
392 | if (!(td->evtdev->features & CLOCK_EVT_FEAT_C3STOP)) | |
393 | return 0; | |
394 | ||
395 | return __tick_broadcast_oneshot_control(state); | |
396 | } | |
0f447051 | 397 | EXPORT_SYMBOL_GPL(tick_broadcast_oneshot_control); |
f32dd117 | 398 | |
52c063d1 | 399 | #ifdef CONFIG_HOTPLUG_CPU |
500f8f9b FW |
400 | void tick_assert_timekeeping_handover(void) |
401 | { | |
402 | WARN_ON_ONCE(tick_do_timer_cpu == smp_processor_id()); | |
403 | } | |
94df7de0 | 404 | /* |
3ad6eb06 | 405 | * Stop the tick and transfer the timekeeping job away from a dying cpu. |
94df7de0 | 406 | */ |
3ad6eb06 | 407 | int tick_cpu_dying(unsigned int dying_cpu) |
94df7de0 | 408 | { |
3ad6eb06 | 409 | /* |
f87cbcb3 TG |
410 | * If the current CPU is the timekeeper, it's the only one that can |
411 | * safely hand over its duty. Also all online CPUs are in stop | |
412 | * machine, guaranteed not to be idle, therefore there is no | |
413 | * concurrency and it's safe to pick any online successor. | |
3ad6eb06 FW |
414 | */ |
415 | if (tick_do_timer_cpu == dying_cpu) | |
f12ad423 | 416 | tick_do_timer_cpu = cpumask_first(cpu_online_mask); |
3ad6eb06 | 417 | |
3f69d04e FW |
418 | /* Make sure the CPU won't try to retake the timekeeping duty */ |
419 | tick_sched_timer_dying(dying_cpu); | |
f04e5122 | 420 | |
ef8969bb FW |
421 | /* Remove CPU from timer broadcasting */ |
422 | tick_offline_cpu(dying_cpu); | |
423 | ||
3ad6eb06 | 424 | return 0; |
94df7de0 SD |
425 | } |
426 | ||
906568c9 TG |
427 | /* |
428 | * Shutdown an event device on a given cpu: | |
429 | * | |
430 | * This is called on a life CPU, when a CPU is dead. So we cannot | |
431 | * access the hardware device itself. | |
432 | * We just set the mode and remove it from the lists. | |
433 | */ | |
a49b116d | 434 | void tick_shutdown(unsigned int cpu) |
906568c9 | 435 | { |
a49b116d | 436 | struct tick_device *td = &per_cpu(tick_cpu_device, cpu); |
906568c9 | 437 | struct clock_event_device *dev = td->evtdev; |
906568c9 | 438 | |
906568c9 TG |
439 | td->mode = TICKDEV_MODE_PERIODIC; |
440 | if (dev) { | |
441 | /* | |
442 | * Prevent that the clock events layer tries to call | |
443 | * the set mode function! | |
444 | */ | |
051ebd10 | 445 | clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED); |
906568c9 | 446 | clockevents_exchange_device(dev, NULL); |
6f7a05d7 | 447 | dev->event_handler = clockevents_handle_noop; |
906568c9 TG |
448 | td->evtdev = NULL; |
449 | } | |
906568c9 | 450 | } |
a49b116d | 451 | #endif |
906568c9 | 452 | |
4ffee521 | 453 | /** |
f46481d0 | 454 | * tick_suspend_local - Suspend the local tick device |
4ffee521 | 455 | * |
f46481d0 | 456 | * Called from the local cpu for freeze with interrupts disabled. |
4ffee521 TG |
457 | * |
458 | * No locks required. Nothing can change the per cpu device. | |
459 | */ | |
7270d11c | 460 | void tick_suspend_local(void) |
6321dd60 | 461 | { |
22127e93 | 462 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
6321dd60 | 463 | |
2344abbc | 464 | clockevents_shutdown(td->evtdev); |
6321dd60 TG |
465 | } |
466 | ||
4ffee521 | 467 | /** |
f46481d0 | 468 | * tick_resume_local - Resume the local tick device |
4ffee521 | 469 | * |
f46481d0 | 470 | * Called from the local CPU for unfreeze or XEN resume magic. |
4ffee521 TG |
471 | * |
472 | * No locks required. Nothing can change the per cpu device. | |
473 | */ | |
f46481d0 | 474 | void tick_resume_local(void) |
6321dd60 | 475 | { |
f46481d0 TG |
476 | struct tick_device *td = this_cpu_ptr(&tick_cpu_device); |
477 | bool broadcast = tick_resume_check_broadcast(); | |
6321dd60 | 478 | |
554ef387 | 479 | clockevents_tick_resume(td->evtdev); |
18de5bc4 TG |
480 | if (!broadcast) { |
481 | if (td->mode == TICKDEV_MODE_PERIODIC) | |
482 | tick_setup_periodic(td->evtdev, 0); | |
483 | else | |
484 | tick_resume_oneshot(); | |
485 | } | |
a761a67f TG |
486 | |
487 | /* | |
488 | * Ensure that hrtimers are up to date and the clockevents device | |
489 | * is reprogrammed correctly when high resolution timers are | |
490 | * enabled. | |
491 | */ | |
492 | hrtimers_resume_local(); | |
6321dd60 TG |
493 | } |
494 | ||
f46481d0 TG |
495 | /** |
496 | * tick_suspend - Suspend the tick and the broadcast device | |
497 | * | |
498 | * Called from syscore_suspend() via timekeeping_suspend with only one | |
499 | * CPU online and interrupts disabled or from tick_unfreeze() under | |
500 | * tick_freeze_lock. | |
501 | * | |
502 | * No locks required. Nothing can change the per cpu device. | |
503 | */ | |
504 | void tick_suspend(void) | |
505 | { | |
506 | tick_suspend_local(); | |
507 | tick_suspend_broadcast(); | |
508 | } | |
509 | ||
510 | /** | |
511 | * tick_resume - Resume the tick and the broadcast device | |
512 | * | |
513 | * Called from syscore_resume() via timekeeping_resume with only one | |
514 | * CPU online and interrupts disabled. | |
515 | * | |
516 | * No locks required. Nothing can change the per cpu device. | |
517 | */ | |
518 | void tick_resume(void) | |
519 | { | |
520 | tick_resume_broadcast(); | |
521 | tick_resume_local(); | |
522 | } | |
523 | ||
87e9b9f1 | 524 | #ifdef CONFIG_SUSPEND |
124cf911 RW |
525 | static DEFINE_RAW_SPINLOCK(tick_freeze_lock); |
526 | static unsigned int tick_freeze_depth; | |
527 | ||
528 | /** | |
529 | * tick_freeze - Suspend the local tick and (possibly) timekeeping. | |
530 | * | |
531 | * Check if this is the last online CPU executing the function and if so, | |
532 | * suspend timekeeping. Otherwise suspend the local tick. | |
533 | * | |
534 | * Call with interrupts disabled. Must be balanced with %tick_unfreeze(). | |
535 | * Interrupts must not be enabled before the subsequent %tick_unfreeze(). | |
536 | */ | |
537 | void tick_freeze(void) | |
538 | { | |
539 | raw_spin_lock(&tick_freeze_lock); | |
540 | ||
541 | tick_freeze_depth++; | |
75e0678e RW |
542 | if (tick_freeze_depth == num_online_cpus()) { |
543 | trace_suspend_resume(TPS("timekeeping_freeze"), | |
544 | smp_processor_id(), true); | |
c1a957d1 | 545 | system_state = SYSTEM_SUSPEND; |
3f2552f7 | 546 | sched_clock_suspend(); |
124cf911 | 547 | timekeeping_suspend(); |
75e0678e | 548 | } else { |
f46481d0 | 549 | tick_suspend_local(); |
75e0678e | 550 | } |
124cf911 RW |
551 | |
552 | raw_spin_unlock(&tick_freeze_lock); | |
553 | } | |
554 | ||
555 | /** | |
556 | * tick_unfreeze - Resume the local tick and (possibly) timekeeping. | |
557 | * | |
558 | * Check if this is the first CPU executing the function and if so, resume | |
559 | * timekeeping. Otherwise resume the local tick. | |
560 | * | |
561 | * Call with interrupts disabled. Must be balanced with %tick_freeze(). | |
562 | * Interrupts must not be enabled after the preceding %tick_freeze(). | |
563 | */ | |
564 | void tick_unfreeze(void) | |
565 | { | |
566 | raw_spin_lock(&tick_freeze_lock); | |
567 | ||
75e0678e | 568 | if (tick_freeze_depth == num_online_cpus()) { |
124cf911 | 569 | timekeeping_resume(); |
3f2552f7 | 570 | sched_clock_resume(); |
c1a957d1 | 571 | system_state = SYSTEM_RUNNING; |
75e0678e RW |
572 | trace_suspend_resume(TPS("timekeeping_freeze"), |
573 | smp_processor_id(), false); | |
574 | } else { | |
5167c506 | 575 | touch_softlockup_watchdog(); |
422fe750 | 576 | tick_resume_local(); |
75e0678e | 577 | } |
124cf911 RW |
578 | |
579 | tick_freeze_depth--; | |
580 | ||
581 | raw_spin_unlock(&tick_freeze_lock); | |
582 | } | |
87e9b9f1 | 583 | #endif /* CONFIG_SUSPEND */ |
124cf911 | 584 | |
906568c9 TG |
585 | /** |
586 | * tick_init - initialize the tick control | |
906568c9 TG |
587 | */ |
588 | void __init tick_init(void) | |
589 | { | |
b352bc1c | 590 | tick_broadcast_init(); |
a80e49e2 | 591 | tick_nohz_init(); |
906568c9 | 592 | } |