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10#include <linux/cpu.h>
11#include <linux/err.h>
12#include <linux/hrtimer.h>
13#include <linux/interrupt.h>
14#include <linux/nmi.h>
15#include <linux/percpu.h>
16#include <linux/profile.h>
17#include <linux/sched.h>
18#include <linux/module.h>
19#include <trace/events/power.h>
20
21#include <asm/irq_regs.h>
22
23#include "tick-internal.h"
24
25
26
27
28DEFINE_PER_CPU(struct tick_device, tick_cpu_device);
29
30
31
32ktime_t tick_next_period;
33ktime_t tick_period;
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48
49int tick_do_timer_cpu __read_mostly = TICK_DO_TIMER_BOOT;
50#ifdef CONFIG_NO_HZ_FULL
51
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54
55
56static int tick_do_timer_boot_cpu __read_mostly = -1;
57#endif
58
59
60
61
62struct tick_device *tick_get_device(int cpu)
63{
64 return &per_cpu(tick_cpu_device, cpu);
65}
66
67
68
69
70int tick_is_oneshot_available(void)
71{
72 struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
73
74 if (!dev || !(dev->features & CLOCK_EVT_FEAT_ONESHOT))
75 return 0;
76 if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
77 return 1;
78 return tick_broadcast_oneshot_available();
79}
80
81
82
83
84static void tick_periodic(int cpu)
85{
86 if (tick_do_timer_cpu == cpu) {
87 raw_spin_lock(&jiffies_lock);
88 write_seqcount_begin(&jiffies_seq);
89
90
91 tick_next_period = ktime_add(tick_next_period, tick_period);
92
93 do_timer(1);
94 write_seqcount_end(&jiffies_seq);
95 raw_spin_unlock(&jiffies_lock);
96 update_wall_time();
97 }
98
99 update_process_times(user_mode(get_irq_regs()));
100 profile_tick(CPU_PROFILING);
101}
102
103
104
105
106void tick_handle_periodic(struct clock_event_device *dev)
107{
108 int cpu = smp_processor_id();
109 ktime_t next = dev->next_event;
110
111 tick_periodic(cpu);
112
113#if defined(CONFIG_HIGH_RES_TIMERS) || defined(CONFIG_NO_HZ_COMMON)
114
115
116
117
118
119 if (dev->event_handler != tick_handle_periodic)
120 return;
121#endif
122
123 if (!clockevent_state_oneshot(dev))
124 return;
125 for (;;) {
126
127
128
129
130 next = ktime_add(next, tick_period);
131
132 if (!clockevents_program_event(dev, next, false))
133 return;
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142
143 if (timekeeping_valid_for_hres())
144 tick_periodic(cpu);
145 }
146}
147
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149
150
151void tick_setup_periodic(struct clock_event_device *dev, int broadcast)
152{
153 tick_set_periodic_handler(dev, broadcast);
154
155
156 if (!tick_device_is_functional(dev))
157 return;
158
159 if ((dev->features & CLOCK_EVT_FEAT_PERIODIC) &&
160 !tick_broadcast_oneshot_active()) {
161 clockevents_switch_state(dev, CLOCK_EVT_STATE_PERIODIC);
162 } else {
163 unsigned int seq;
164 ktime_t next;
165
166 do {
167 seq = read_seqcount_begin(&jiffies_seq);
168 next = tick_next_period;
169 } while (read_seqcount_retry(&jiffies_seq, seq));
170
171 clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
172
173 for (;;) {
174 if (!clockevents_program_event(dev, next, false))
175 return;
176 next = ktime_add(next, tick_period);
177 }
178 }
179}
180
181#ifdef CONFIG_NO_HZ_FULL
182static 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
191static 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
201
202
203
204static void tick_setup_device(struct tick_device *td,
205 struct clock_event_device *newdev, int cpu,
206 const struct cpumask *cpumask)
207{
208 void (*handler)(struct clock_event_device *) = NULL;
209 ktime_t next_event = 0;
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213
214 if (!td->evtdev) {
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219 if (tick_do_timer_cpu == TICK_DO_TIMER_BOOT) {
220 tick_do_timer_cpu = cpu;
221
222 tick_next_period = ktime_get();
223 tick_period = NSEC_PER_SEC / HZ;
224#ifdef CONFIG_NO_HZ_FULL
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230
231 if (tick_nohz_full_cpu(cpu))
232 tick_do_timer_boot_cpu = cpu;
233
234 } else if (tick_do_timer_boot_cpu != -1 &&
235 !tick_nohz_full_cpu(cpu)) {
236 tick_take_do_timer_from_boot();
237 tick_do_timer_boot_cpu = -1;
238 WARN_ON(tick_do_timer_cpu != cpu);
239#endif
240 }
241
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244
245 td->mode = TICKDEV_MODE_PERIODIC;
246 } else {
247 handler = td->evtdev->event_handler;
248 next_event = td->evtdev->next_event;
249 td->evtdev->event_handler = clockevents_handle_noop;
250 }
251
252 td->evtdev = newdev;
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258 if (!cpumask_equal(newdev->cpumask, cpumask))
259 irq_set_affinity(newdev->irq, cpumask);
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268 if (tick_device_uses_broadcast(newdev, cpu))
269 return;
270
271 if (td->mode == TICKDEV_MODE_PERIODIC)
272 tick_setup_periodic(newdev, 0);
273 else
274 tick_setup_oneshot(newdev, handler, next_event);
275}
276
277void tick_install_replacement(struct clock_event_device *newdev)
278{
279 struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
280 int cpu = smp_processor_id();
281
282 clockevents_exchange_device(td->evtdev, newdev);
283 tick_setup_device(td, newdev, cpu, cpumask_of(cpu));
284 if (newdev->features & CLOCK_EVT_FEAT_ONESHOT)
285 tick_oneshot_notify();
286}
287
288static bool tick_check_percpu(struct clock_event_device *curdev,
289 struct clock_event_device *newdev, int cpu)
290{
291 if (!cpumask_test_cpu(cpu, newdev->cpumask))
292 return false;
293 if (cpumask_equal(newdev->cpumask, cpumask_of(cpu)))
294 return true;
295
296 if (newdev->irq >= 0 && !irq_can_set_affinity(newdev->irq))
297 return false;
298
299 if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu)))
300 return false;
301 return true;
302}
303
304static bool tick_check_preferred(struct clock_event_device *curdev,
305 struct clock_event_device *newdev)
306{
307
308 if (!(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) {
309 if (curdev && (curdev->features & CLOCK_EVT_FEAT_ONESHOT))
310 return false;
311 if (tick_oneshot_mode_active())
312 return false;
313 }
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318
319 return !curdev ||
320 newdev->rating > curdev->rating ||
321 !cpumask_equal(curdev->cpumask, newdev->cpumask);
322}
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328bool tick_check_replacement(struct clock_event_device *curdev,
329 struct clock_event_device *newdev)
330{
331 if (!tick_check_percpu(curdev, newdev, smp_processor_id()))
332 return false;
333
334 return tick_check_preferred(curdev, newdev);
335}
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340
341void tick_check_new_device(struct clock_event_device *newdev)
342{
343 struct clock_event_device *curdev;
344 struct tick_device *td;
345 int cpu;
346
347 cpu = smp_processor_id();
348 td = &per_cpu(tick_cpu_device, cpu);
349 curdev = td->evtdev;
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351
352 if (!tick_check_percpu(curdev, newdev, cpu))
353 goto out_bc;
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356 if (!tick_check_preferred(curdev, newdev))
357 goto out_bc;
358
359 if (!try_module_get(newdev->owner))
360 return;
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366
367 if (tick_is_broadcast_device(curdev)) {
368 clockevents_shutdown(curdev);
369 curdev = NULL;
370 }
371 clockevents_exchange_device(curdev, newdev);
372 tick_setup_device(td, newdev, cpu, cpumask_of(cpu));
373 if (newdev->features & CLOCK_EVT_FEAT_ONESHOT)
374 tick_oneshot_notify();
375 return;
376
377out_bc:
378
379
380
381 tick_install_broadcast_device(newdev);
382}
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395int tick_broadcast_oneshot_control(enum tick_broadcast_state state)
396{
397 struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
398
399 if (!(td->evtdev->features & CLOCK_EVT_FEAT_C3STOP))
400 return 0;
401
402 return __tick_broadcast_oneshot_control(state);
403}
404EXPORT_SYMBOL_GPL(tick_broadcast_oneshot_control);
405
406#ifdef CONFIG_HOTPLUG_CPU
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413void tick_handover_do_timer(void)
414{
415 if (tick_do_timer_cpu == smp_processor_id()) {
416 int cpu = cpumask_first(cpu_online_mask);
417
418 tick_do_timer_cpu = (cpu < nr_cpu_ids) ? cpu :
419 TICK_DO_TIMER_NONE;
420 }
421}
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430void tick_shutdown(unsigned int cpu)
431{
432 struct tick_device *td = &per_cpu(tick_cpu_device, cpu);
433 struct clock_event_device *dev = td->evtdev;
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435 td->mode = TICKDEV_MODE_PERIODIC;
436 if (dev) {
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441 clockevent_set_state(dev, CLOCK_EVT_STATE_DETACHED);
442 clockevents_exchange_device(dev, NULL);
443 dev->event_handler = clockevents_handle_noop;
444 td->evtdev = NULL;
445 }
446}
447#endif
448
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455
456void tick_suspend_local(void)
457{
458 struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
459
460 clockevents_shutdown(td->evtdev);
461}
462
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470void tick_resume_local(void)
471{
472 struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
473 bool broadcast = tick_resume_check_broadcast();
474
475 clockevents_tick_resume(td->evtdev);
476 if (!broadcast) {
477 if (td->mode == TICKDEV_MODE_PERIODIC)
478 tick_setup_periodic(td->evtdev, 0);
479 else
480 tick_resume_oneshot();
481 }
482}
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493void tick_suspend(void)
494{
495 tick_suspend_local();
496 tick_suspend_broadcast();
497}
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507void tick_resume(void)
508{
509 tick_resume_broadcast();
510 tick_resume_local();
511}
512
513#ifdef CONFIG_SUSPEND
514static DEFINE_RAW_SPINLOCK(tick_freeze_lock);
515static unsigned int tick_freeze_depth;
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526void tick_freeze(void)
527{
528 raw_spin_lock(&tick_freeze_lock);
529
530 tick_freeze_depth++;
531 if (tick_freeze_depth == num_online_cpus()) {
532 trace_suspend_resume(TPS("timekeeping_freeze"),
533 smp_processor_id(), true);
534 system_state = SYSTEM_SUSPEND;
535 sched_clock_suspend();
536 timekeeping_suspend();
537 } else {
538 tick_suspend_local();
539 }
540
541 raw_spin_unlock(&tick_freeze_lock);
542}
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553void tick_unfreeze(void)
554{
555 raw_spin_lock(&tick_freeze_lock);
556
557 if (tick_freeze_depth == num_online_cpus()) {
558 timekeeping_resume();
559 sched_clock_resume();
560 system_state = SYSTEM_RUNNING;
561 trace_suspend_resume(TPS("timekeeping_freeze"),
562 smp_processor_id(), false);
563 } else {
564 touch_softlockup_watchdog();
565 tick_resume_local();
566 }
567
568 tick_freeze_depth--;
569
570 raw_spin_unlock(&tick_freeze_lock);
571}
572#endif
573
574
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576
577void __init tick_init(void)
578{
579 tick_broadcast_init();
580 tick_nohz_init();
581}
582