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1/*
2 * linux/kernel/time/tick-broadcast.c
3 *
4 * This file contains functions which emulate a local clock-event
5 * device via a broadcast event source.
6 *
7 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
8 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
9 * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
10 *
11 * This code is licenced under the GPL version 2. For details see
12 * kernel-base/COPYING.
13 */
14#include <linux/cpu.h>
15#include <linux/err.h>
16#include <linux/hrtimer.h>
17#include <linux/interrupt.h>
18#include <linux/percpu.h>
19#include <linux/profile.h>
20#include <linux/sched.h>
21
22#include "tick-internal.h"
23
24/*
25 * Broadcast support for broken x86 hardware, where the local apic
26 * timer stops in C3 state.
27 */
28
29static struct tick_device tick_broadcast_device;
30/* FIXME: Use cpumask_var_t. */
31static DECLARE_BITMAP(tick_broadcast_mask, NR_CPUS);
32static DECLARE_BITMAP(tmpmask, NR_CPUS);
33static DEFINE_RAW_SPINLOCK(tick_broadcast_lock);
34static int tick_broadcast_force;
35
36#ifdef CONFIG_TICK_ONESHOT
37static void tick_broadcast_clear_oneshot(int cpu);
38#else
39static inline void tick_broadcast_clear_oneshot(int cpu) { }
40#endif
41
42/*
43 * Debugging: see timer_list.c
44 */
45struct tick_device *tick_get_broadcast_device(void)
46{
47 return &tick_broadcast_device;
48}
49
50struct cpumask *tick_get_broadcast_mask(void)
51{
52 return to_cpumask(tick_broadcast_mask);
53}
54
55/*
56 * Start the device in periodic mode
57 */
58static void tick_broadcast_start_periodic(struct clock_event_device *bc)
59{
60 if (bc)
61 tick_setup_periodic(bc, 1);
62}
63
64/*
65 * Check, if the device can be utilized as broadcast device:
66 */
67int tick_check_broadcast_device(struct clock_event_device *dev)
68{
69 if ((tick_broadcast_device.evtdev &&
70 tick_broadcast_device.evtdev->rating >= dev->rating) ||
71 (dev->features & CLOCK_EVT_FEAT_C3STOP))
72 return 0;
73
74 clockevents_exchange_device(tick_broadcast_device.evtdev, dev);
75 tick_broadcast_device.evtdev = dev;
76 if (!cpumask_empty(tick_get_broadcast_mask()))
77 tick_broadcast_start_periodic(dev);
78 return 1;
79}
80
81/*
82 * Check, if the device is the broadcast device
83 */
84int tick_is_broadcast_device(struct clock_event_device *dev)
85{
86 return (dev && tick_broadcast_device.evtdev == dev);
87}
88
89/*
90 * Check, if the device is disfunctional and a place holder, which
91 * needs to be handled by the broadcast device.
92 */
93int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
94{
95 unsigned long flags;
96 int ret = 0;
97
98 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
99
100 /*
101 * Devices might be registered with both periodic and oneshot
102 * mode disabled. This signals, that the device needs to be
103 * operated from the broadcast device and is a placeholder for
104 * the cpu local device.
105 */
106 if (!tick_device_is_functional(dev)) {
107 dev->event_handler = tick_handle_periodic;
108 cpumask_set_cpu(cpu, tick_get_broadcast_mask());
109 tick_broadcast_start_periodic(tick_broadcast_device.evtdev);
110 ret = 1;
111 } else {
112 /*
113 * When the new device is not affected by the stop
114 * feature and the cpu is marked in the broadcast mask
115 * then clear the broadcast bit.
116 */
117 if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) {
118 int cpu = smp_processor_id();
119
120 cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
121 tick_broadcast_clear_oneshot(cpu);
122 }
123 }
124 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
125 return ret;
126}
127
128/*
129 * Broadcast the event to the cpus, which are set in the mask (mangled).
130 */
131static void tick_do_broadcast(struct cpumask *mask)
132{
133 int cpu = smp_processor_id();
134 struct tick_device *td;
135
136 /*
137 * Check, if the current cpu is in the mask
138 */
139 if (cpumask_test_cpu(cpu, mask)) {
140 cpumask_clear_cpu(cpu, mask);
141 td = &per_cpu(tick_cpu_device, cpu);
142 td->evtdev->event_handler(td->evtdev);
143 }
144
145 if (!cpumask_empty(mask)) {
146 /*
147 * It might be necessary to actually check whether the devices
148 * have different broadcast functions. For now, just use the
149 * one of the first device. This works as long as we have this
150 * misfeature only on x86 (lapic)
151 */
152 td = &per_cpu(tick_cpu_device, cpumask_first(mask));
153 td->evtdev->broadcast(mask);
154 }
155}
156
157/*
158 * Periodic broadcast:
159 * - invoke the broadcast handlers
160 */
161static void tick_do_periodic_broadcast(void)
162{
163 raw_spin_lock(&tick_broadcast_lock);
164
165 cpumask_and(to_cpumask(tmpmask),
166 cpu_online_mask, tick_get_broadcast_mask());
167 tick_do_broadcast(to_cpumask(tmpmask));
168
169 raw_spin_unlock(&tick_broadcast_lock);
170}
171
172/*
173 * Event handler for periodic broadcast ticks
174 */
175static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
176{
177 ktime_t next;
178
179 tick_do_periodic_broadcast();
180
181 /*
182 * The device is in periodic mode. No reprogramming necessary:
183 */
184 if (dev->mode == CLOCK_EVT_MODE_PERIODIC)
185 return;
186
187 /*
188 * Setup the next period for devices, which do not have
189 * periodic mode. We read dev->next_event first and add to it
190 * when the event already expired. clockevents_program_event()
191 * sets dev->next_event only when the event is really
192 * programmed to the device.
193 */
194 for (next = dev->next_event; ;) {
195 next = ktime_add(next, tick_period);
196
197 if (!clockevents_program_event(dev, next, false))
198 return;
199 tick_do_periodic_broadcast();
200 }
201}
202
203/*
204 * Powerstate information: The system enters/leaves a state, where
205 * affected devices might stop
206 */
207static void tick_do_broadcast_on_off(unsigned long *reason)
208{
209 struct clock_event_device *bc, *dev;
210 struct tick_device *td;
211 unsigned long flags;
212 int cpu, bc_stopped;
213
214 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
215
216 cpu = smp_processor_id();
217 td = &per_cpu(tick_cpu_device, cpu);
218 dev = td->evtdev;
219 bc = tick_broadcast_device.evtdev;
220
221 /*
222 * Is the device not affected by the powerstate ?
223 */
224 if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))
225 goto out;
226
227 if (!tick_device_is_functional(dev))
228 goto out;
229
230 bc_stopped = cpumask_empty(tick_get_broadcast_mask());
231
232 switch (*reason) {
233 case CLOCK_EVT_NOTIFY_BROADCAST_ON:
234 case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
235 if (!cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
236 cpumask_set_cpu(cpu, tick_get_broadcast_mask());
237 if (tick_broadcast_device.mode ==
238 TICKDEV_MODE_PERIODIC)
239 clockevents_shutdown(dev);
240 }
241 if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
242 tick_broadcast_force = 1;
243 break;
244 case CLOCK_EVT_NOTIFY_BROADCAST_OFF:
245 if (!tick_broadcast_force &&
246 cpumask_test_cpu(cpu, tick_get_broadcast_mask())) {
247 cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
248 if (tick_broadcast_device.mode ==
249 TICKDEV_MODE_PERIODIC)
250 tick_setup_periodic(dev, 0);
251 }
252 break;
253 }
254
255 if (cpumask_empty(tick_get_broadcast_mask())) {
256 if (!bc_stopped)
257 clockevents_shutdown(bc);
258 } else if (bc_stopped) {
259 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
260 tick_broadcast_start_periodic(bc);
261 else
262 tick_broadcast_setup_oneshot(bc);
263 }
264out:
265 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
266}
267
268/*
269 * Powerstate information: The system enters/leaves a state, where
270 * affected devices might stop.
271 */
272void tick_broadcast_on_off(unsigned long reason, int *oncpu)
273{
274 if (!cpumask_test_cpu(*oncpu, cpu_online_mask))
275 printk(KERN_ERR "tick-broadcast: ignoring broadcast for "
276 "offline CPU #%d\n", *oncpu);
277 else
278 tick_do_broadcast_on_off(&reason);
279}
280
281/*
282 * Set the periodic handler depending on broadcast on/off
283 */
284void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
285{
286 if (!broadcast)
287 dev->event_handler = tick_handle_periodic;
288 else
289 dev->event_handler = tick_handle_periodic_broadcast;
290}
291
292/*
293 * Remove a CPU from broadcasting
294 */
295void tick_shutdown_broadcast(unsigned int *cpup)
296{
297 struct clock_event_device *bc;
298 unsigned long flags;
299 unsigned int cpu = *cpup;
300
301 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
302
303 bc = tick_broadcast_device.evtdev;
304 cpumask_clear_cpu(cpu, tick_get_broadcast_mask());
305
306 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
307 if (bc && cpumask_empty(tick_get_broadcast_mask()))
308 clockevents_shutdown(bc);
309 }
310
311 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
312}
313
314void tick_suspend_broadcast(void)
315{
316 struct clock_event_device *bc;
317 unsigned long flags;
318
319 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
320
321 bc = tick_broadcast_device.evtdev;
322 if (bc)
323 clockevents_shutdown(bc);
324
325 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
326}
327
328int tick_resume_broadcast(void)
329{
330 struct clock_event_device *bc;
331 unsigned long flags;
332 int broadcast = 0;
333
334 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
335
336 bc = tick_broadcast_device.evtdev;
337
338 if (bc) {
339 clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME);
340
341 switch (tick_broadcast_device.mode) {
342 case TICKDEV_MODE_PERIODIC:
343 if (!cpumask_empty(tick_get_broadcast_mask()))
344 tick_broadcast_start_periodic(bc);
345 broadcast = cpumask_test_cpu(smp_processor_id(),
346 tick_get_broadcast_mask());
347 break;
348 case TICKDEV_MODE_ONESHOT:
349 if (!cpumask_empty(tick_get_broadcast_mask()))
350 broadcast = tick_resume_broadcast_oneshot(bc);
351 break;
352 }
353 }
354 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
355
356 return broadcast;
357}
358
359
360#ifdef CONFIG_TICK_ONESHOT
361
362/* FIXME: use cpumask_var_t. */
363static DECLARE_BITMAP(tick_broadcast_oneshot_mask, NR_CPUS);
364
365/*
366 * Exposed for debugging: see timer_list.c
367 */
368struct cpumask *tick_get_broadcast_oneshot_mask(void)
369{
370 return to_cpumask(tick_broadcast_oneshot_mask);
371}
372
373static int tick_broadcast_set_event(ktime_t expires, int force)
374{
375 struct clock_event_device *bc = tick_broadcast_device.evtdev;
376
377 if (bc->mode != CLOCK_EVT_MODE_ONESHOT)
378 clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
379
380 return clockevents_program_event(bc, expires, force);
381}
382
383int tick_resume_broadcast_oneshot(struct clock_event_device *bc)
384{
385 clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
386 return 0;
387}
388
389/*
390 * Called from irq_enter() when idle was interrupted to reenable the
391 * per cpu device.
392 */
393void tick_check_oneshot_broadcast(int cpu)
394{
395 if (cpumask_test_cpu(cpu, to_cpumask(tick_broadcast_oneshot_mask))) {
396 struct tick_device *td = &per_cpu(tick_cpu_device, cpu);
397
398 clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_ONESHOT);
399 }
400}
401
402/*
403 * Handle oneshot mode broadcasting
404 */
405static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
406{
407 struct tick_device *td;
408 ktime_t now, next_event;
409 int cpu;
410
411 raw_spin_lock(&tick_broadcast_lock);
412again:
413 dev->next_event.tv64 = KTIME_MAX;
414 next_event.tv64 = KTIME_MAX;
415 cpumask_clear(to_cpumask(tmpmask));
416 now = ktime_get();
417 /* Find all expired events */
418 for_each_cpu(cpu, tick_get_broadcast_oneshot_mask()) {
419 td = &per_cpu(tick_cpu_device, cpu);
420 if (td->evtdev->next_event.tv64 <= now.tv64)
421 cpumask_set_cpu(cpu, to_cpumask(tmpmask));
422 else if (td->evtdev->next_event.tv64 < next_event.tv64)
423 next_event.tv64 = td->evtdev->next_event.tv64;
424 }
425
426 /*
427 * Wakeup the cpus which have an expired event.
428 */
429 tick_do_broadcast(to_cpumask(tmpmask));
430
431 /*
432 * Two reasons for reprogram:
433 *
434 * - The global event did not expire any CPU local
435 * events. This happens in dyntick mode, as the maximum PIT
436 * delta is quite small.
437 *
438 * - There are pending events on sleeping CPUs which were not
439 * in the event mask
440 */
441 if (next_event.tv64 != KTIME_MAX) {
442 /*
443 * Rearm the broadcast device. If event expired,
444 * repeat the above
445 */
446 if (tick_broadcast_set_event(next_event, 0))
447 goto again;
448 }
449 raw_spin_unlock(&tick_broadcast_lock);
450}
451
452/*
453 * Powerstate information: The system enters/leaves a state, where
454 * affected devices might stop
455 */
456void tick_broadcast_oneshot_control(unsigned long reason)
457{
458 struct clock_event_device *bc, *dev;
459 struct tick_device *td;
460 unsigned long flags;
461 int cpu;
462
463 /*
464 * Periodic mode does not care about the enter/exit of power
465 * states
466 */
467 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
468 return;
469
470 /*
471 * We are called with preemtion disabled from the depth of the
472 * idle code, so we can't be moved away.
473 */
474 cpu = smp_processor_id();
475 td = &per_cpu(tick_cpu_device, cpu);
476 dev = td->evtdev;
477
478 if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
479 return;
480
481 bc = tick_broadcast_device.evtdev;
482
483 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
484 if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
485 if (!cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
486 cpumask_set_cpu(cpu, tick_get_broadcast_oneshot_mask());
487 clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN);
488 if (dev->next_event.tv64 < bc->next_event.tv64)
489 tick_broadcast_set_event(dev->next_event, 1);
490 }
491 } else {
492 if (cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
493 cpumask_clear_cpu(cpu,
494 tick_get_broadcast_oneshot_mask());
495 clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT);
496 if (dev->next_event.tv64 != KTIME_MAX)
497 tick_program_event(dev->next_event, 1);
498 }
499 }
500 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
501}
502
503/*
504 * Reset the one shot broadcast for a cpu
505 *
506 * Called with tick_broadcast_lock held
507 */
508static void tick_broadcast_clear_oneshot(int cpu)
509{
510 cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask());
511}
512
513static void tick_broadcast_init_next_event(struct cpumask *mask,
514 ktime_t expires)
515{
516 struct tick_device *td;
517 int cpu;
518
519 for_each_cpu(cpu, mask) {
520 td = &per_cpu(tick_cpu_device, cpu);
521 if (td->evtdev)
522 td->evtdev->next_event = expires;
523 }
524}
525
526/**
527 * tick_broadcast_setup_oneshot - setup the broadcast device
528 */
529void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
530{
531 int cpu = smp_processor_id();
532
533 /* Set it up only once ! */
534 if (bc->event_handler != tick_handle_oneshot_broadcast) {
535 int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
536
537 bc->event_handler = tick_handle_oneshot_broadcast;
538
539 /* Take the do_timer update */
540 tick_do_timer_cpu = cpu;
541
542 /*
543 * We must be careful here. There might be other CPUs
544 * waiting for periodic broadcast. We need to set the
545 * oneshot_mask bits for those and program the
546 * broadcast device to fire.
547 */
548 cpumask_copy(to_cpumask(tmpmask), tick_get_broadcast_mask());
549 cpumask_clear_cpu(cpu, to_cpumask(tmpmask));
550 cpumask_or(tick_get_broadcast_oneshot_mask(),
551 tick_get_broadcast_oneshot_mask(),
552 to_cpumask(tmpmask));
553
554 if (was_periodic && !cpumask_empty(to_cpumask(tmpmask))) {
555 clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
556 tick_broadcast_init_next_event(to_cpumask(tmpmask),
557 tick_next_period);
558 tick_broadcast_set_event(tick_next_period, 1);
559 } else
560 bc->next_event.tv64 = KTIME_MAX;
561 } else {
562 /*
563 * The first cpu which switches to oneshot mode sets
564 * the bit for all other cpus which are in the general
565 * (periodic) broadcast mask. So the bit is set and
566 * would prevent the first broadcast enter after this
567 * to program the bc device.
568 */
569 tick_broadcast_clear_oneshot(cpu);
570 }
571}
572
573/*
574 * Select oneshot operating mode for the broadcast device
575 */
576void tick_broadcast_switch_to_oneshot(void)
577{
578 struct clock_event_device *bc;
579 unsigned long flags;
580
581 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
582
583 tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
584 bc = tick_broadcast_device.evtdev;
585 if (bc)
586 tick_broadcast_setup_oneshot(bc);
587
588 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
589}
590
591
592/*
593 * Remove a dead CPU from broadcasting
594 */
595void tick_shutdown_broadcast_oneshot(unsigned int *cpup)
596{
597 unsigned long flags;
598 unsigned int cpu = *cpup;
599
600 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
601
602 /*
603 * Clear the broadcast mask flag for the dead cpu, but do not
604 * stop the broadcast device!
605 */
606 cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask());
607
608 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
609}
610
611/*
612 * Check, whether the broadcast device is in one shot mode
613 */
614int tick_broadcast_oneshot_active(void)
615{
616 return tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT;
617}
618
619/*
620 * Check whether the broadcast device supports oneshot.
621 */
622bool tick_broadcast_oneshot_available(void)
623{
624 struct clock_event_device *bc = tick_broadcast_device.evtdev;
625
626 return bc ? bc->features & CLOCK_EVT_FEAT_ONESHOT : false;
627}
628
629#endif
1/*
2 * linux/kernel/time/tick-broadcast.c
3 *
4 * This file contains functions which emulate a local clock-event
5 * device via a broadcast event source.
6 *
7 * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
8 * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
9 * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner
10 *
11 * This code is licenced under the GPL version 2. For details see
12 * kernel-base/COPYING.
13 */
14#include <linux/cpu.h>
15#include <linux/err.h>
16#include <linux/hrtimer.h>
17#include <linux/interrupt.h>
18#include <linux/percpu.h>
19#include <linux/profile.h>
20#include <linux/sched.h>
21#include <linux/smp.h>
22#include <linux/module.h>
23
24#include "tick-internal.h"
25
26/*
27 * Broadcast support for broken x86 hardware, where the local apic
28 * timer stops in C3 state.
29 */
30
31static struct tick_device tick_broadcast_device;
32static cpumask_var_t tick_broadcast_mask;
33static cpumask_var_t tick_broadcast_on;
34static cpumask_var_t tmpmask;
35static DEFINE_RAW_SPINLOCK(tick_broadcast_lock);
36static int tick_broadcast_forced;
37
38#ifdef CONFIG_TICK_ONESHOT
39static void tick_broadcast_clear_oneshot(int cpu);
40static void tick_resume_broadcast_oneshot(struct clock_event_device *bc);
41#else
42static inline void tick_broadcast_clear_oneshot(int cpu) { }
43static inline void tick_resume_broadcast_oneshot(struct clock_event_device *bc) { }
44#endif
45
46/*
47 * Debugging: see timer_list.c
48 */
49struct tick_device *tick_get_broadcast_device(void)
50{
51 return &tick_broadcast_device;
52}
53
54struct cpumask *tick_get_broadcast_mask(void)
55{
56 return tick_broadcast_mask;
57}
58
59/*
60 * Start the device in periodic mode
61 */
62static void tick_broadcast_start_periodic(struct clock_event_device *bc)
63{
64 if (bc)
65 tick_setup_periodic(bc, 1);
66}
67
68/*
69 * Check, if the device can be utilized as broadcast device:
70 */
71static bool tick_check_broadcast_device(struct clock_event_device *curdev,
72 struct clock_event_device *newdev)
73{
74 if ((newdev->features & CLOCK_EVT_FEAT_DUMMY) ||
75 (newdev->features & CLOCK_EVT_FEAT_PERCPU) ||
76 (newdev->features & CLOCK_EVT_FEAT_C3STOP))
77 return false;
78
79 if (tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT &&
80 !(newdev->features & CLOCK_EVT_FEAT_ONESHOT))
81 return false;
82
83 return !curdev || newdev->rating > curdev->rating;
84}
85
86/*
87 * Conditionally install/replace broadcast device
88 */
89void tick_install_broadcast_device(struct clock_event_device *dev)
90{
91 struct clock_event_device *cur = tick_broadcast_device.evtdev;
92
93 if (!tick_check_broadcast_device(cur, dev))
94 return;
95
96 if (!try_module_get(dev->owner))
97 return;
98
99 clockevents_exchange_device(cur, dev);
100 if (cur)
101 cur->event_handler = clockevents_handle_noop;
102 tick_broadcast_device.evtdev = dev;
103 if (!cpumask_empty(tick_broadcast_mask))
104 tick_broadcast_start_periodic(dev);
105 /*
106 * Inform all cpus about this. We might be in a situation
107 * where we did not switch to oneshot mode because the per cpu
108 * devices are affected by CLOCK_EVT_FEAT_C3STOP and the lack
109 * of a oneshot capable broadcast device. Without that
110 * notification the systems stays stuck in periodic mode
111 * forever.
112 */
113 if (dev->features & CLOCK_EVT_FEAT_ONESHOT)
114 tick_clock_notify();
115}
116
117/*
118 * Check, if the device is the broadcast device
119 */
120int tick_is_broadcast_device(struct clock_event_device *dev)
121{
122 return (dev && tick_broadcast_device.evtdev == dev);
123}
124
125int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq)
126{
127 int ret = -ENODEV;
128
129 if (tick_is_broadcast_device(dev)) {
130 raw_spin_lock(&tick_broadcast_lock);
131 ret = __clockevents_update_freq(dev, freq);
132 raw_spin_unlock(&tick_broadcast_lock);
133 }
134 return ret;
135}
136
137
138static void err_broadcast(const struct cpumask *mask)
139{
140 pr_crit_once("Failed to broadcast timer tick. Some CPUs may be unresponsive.\n");
141}
142
143static void tick_device_setup_broadcast_func(struct clock_event_device *dev)
144{
145 if (!dev->broadcast)
146 dev->broadcast = tick_broadcast;
147 if (!dev->broadcast) {
148 pr_warn_once("%s depends on broadcast, but no broadcast function available\n",
149 dev->name);
150 dev->broadcast = err_broadcast;
151 }
152}
153
154/*
155 * Check, if the device is disfunctional and a place holder, which
156 * needs to be handled by the broadcast device.
157 */
158int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
159{
160 struct clock_event_device *bc = tick_broadcast_device.evtdev;
161 unsigned long flags;
162 int ret = 0;
163
164 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
165
166 /*
167 * Devices might be registered with both periodic and oneshot
168 * mode disabled. This signals, that the device needs to be
169 * operated from the broadcast device and is a placeholder for
170 * the cpu local device.
171 */
172 if (!tick_device_is_functional(dev)) {
173 dev->event_handler = tick_handle_periodic;
174 tick_device_setup_broadcast_func(dev);
175 cpumask_set_cpu(cpu, tick_broadcast_mask);
176 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
177 tick_broadcast_start_periodic(bc);
178 else
179 tick_broadcast_setup_oneshot(bc);
180 ret = 1;
181 } else {
182 /*
183 * Clear the broadcast bit for this cpu if the
184 * device is not power state affected.
185 */
186 if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
187 cpumask_clear_cpu(cpu, tick_broadcast_mask);
188 else
189 tick_device_setup_broadcast_func(dev);
190
191 /*
192 * Clear the broadcast bit if the CPU is not in
193 * periodic broadcast on state.
194 */
195 if (!cpumask_test_cpu(cpu, tick_broadcast_on))
196 cpumask_clear_cpu(cpu, tick_broadcast_mask);
197
198 switch (tick_broadcast_device.mode) {
199 case TICKDEV_MODE_ONESHOT:
200 /*
201 * If the system is in oneshot mode we can
202 * unconditionally clear the oneshot mask bit,
203 * because the CPU is running and therefore
204 * not in an idle state which causes the power
205 * state affected device to stop. Let the
206 * caller initialize the device.
207 */
208 tick_broadcast_clear_oneshot(cpu);
209 ret = 0;
210 break;
211
212 case TICKDEV_MODE_PERIODIC:
213 /*
214 * If the system is in periodic mode, check
215 * whether the broadcast device can be
216 * switched off now.
217 */
218 if (cpumask_empty(tick_broadcast_mask) && bc)
219 clockevents_shutdown(bc);
220 /*
221 * If we kept the cpu in the broadcast mask,
222 * tell the caller to leave the per cpu device
223 * in shutdown state. The periodic interrupt
224 * is delivered by the broadcast device, if
225 * the broadcast device exists and is not
226 * hrtimer based.
227 */
228 if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER))
229 ret = cpumask_test_cpu(cpu, tick_broadcast_mask);
230 break;
231 default:
232 break;
233 }
234 }
235 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
236 return ret;
237}
238
239#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
240int tick_receive_broadcast(void)
241{
242 struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
243 struct clock_event_device *evt = td->evtdev;
244
245 if (!evt)
246 return -ENODEV;
247
248 if (!evt->event_handler)
249 return -EINVAL;
250
251 evt->event_handler(evt);
252 return 0;
253}
254#endif
255
256/*
257 * Broadcast the event to the cpus, which are set in the mask (mangled).
258 */
259static bool tick_do_broadcast(struct cpumask *mask)
260{
261 int cpu = smp_processor_id();
262 struct tick_device *td;
263 bool local = false;
264
265 /*
266 * Check, if the current cpu is in the mask
267 */
268 if (cpumask_test_cpu(cpu, mask)) {
269 struct clock_event_device *bc = tick_broadcast_device.evtdev;
270
271 cpumask_clear_cpu(cpu, mask);
272 /*
273 * We only run the local handler, if the broadcast
274 * device is not hrtimer based. Otherwise we run into
275 * a hrtimer recursion.
276 *
277 * local timer_interrupt()
278 * local_handler()
279 * expire_hrtimers()
280 * bc_handler()
281 * local_handler()
282 * expire_hrtimers()
283 */
284 local = !(bc->features & CLOCK_EVT_FEAT_HRTIMER);
285 }
286
287 if (!cpumask_empty(mask)) {
288 /*
289 * It might be necessary to actually check whether the devices
290 * have different broadcast functions. For now, just use the
291 * one of the first device. This works as long as we have this
292 * misfeature only on x86 (lapic)
293 */
294 td = &per_cpu(tick_cpu_device, cpumask_first(mask));
295 td->evtdev->broadcast(mask);
296 }
297 return local;
298}
299
300/*
301 * Periodic broadcast:
302 * - invoke the broadcast handlers
303 */
304static bool tick_do_periodic_broadcast(void)
305{
306 cpumask_and(tmpmask, cpu_online_mask, tick_broadcast_mask);
307 return tick_do_broadcast(tmpmask);
308}
309
310/*
311 * Event handler for periodic broadcast ticks
312 */
313static void tick_handle_periodic_broadcast(struct clock_event_device *dev)
314{
315 struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
316 bool bc_local;
317
318 raw_spin_lock(&tick_broadcast_lock);
319
320 /* Handle spurious interrupts gracefully */
321 if (clockevent_state_shutdown(tick_broadcast_device.evtdev)) {
322 raw_spin_unlock(&tick_broadcast_lock);
323 return;
324 }
325
326 bc_local = tick_do_periodic_broadcast();
327
328 if (clockevent_state_oneshot(dev)) {
329 ktime_t next = ktime_add(dev->next_event, tick_period);
330
331 clockevents_program_event(dev, next, true);
332 }
333 raw_spin_unlock(&tick_broadcast_lock);
334
335 /*
336 * We run the handler of the local cpu after dropping
337 * tick_broadcast_lock because the handler might deadlock when
338 * trying to switch to oneshot mode.
339 */
340 if (bc_local)
341 td->evtdev->event_handler(td->evtdev);
342}
343
344/**
345 * tick_broadcast_control - Enable/disable or force broadcast mode
346 * @mode: The selected broadcast mode
347 *
348 * Called when the system enters a state where affected tick devices
349 * might stop. Note: TICK_BROADCAST_FORCE cannot be undone.
350 */
351void tick_broadcast_control(enum tick_broadcast_mode mode)
352{
353 struct clock_event_device *bc, *dev;
354 struct tick_device *td;
355 int cpu, bc_stopped;
356 unsigned long flags;
357
358 /* Protects also the local clockevent device. */
359 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
360 td = this_cpu_ptr(&tick_cpu_device);
361 dev = td->evtdev;
362
363 /*
364 * Is the device not affected by the powerstate ?
365 */
366 if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP))
367 goto out;
368
369 if (!tick_device_is_functional(dev))
370 goto out;
371
372 cpu = smp_processor_id();
373 bc = tick_broadcast_device.evtdev;
374 bc_stopped = cpumask_empty(tick_broadcast_mask);
375
376 switch (mode) {
377 case TICK_BROADCAST_FORCE:
378 tick_broadcast_forced = 1;
379 case TICK_BROADCAST_ON:
380 cpumask_set_cpu(cpu, tick_broadcast_on);
381 if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_mask)) {
382 /*
383 * Only shutdown the cpu local device, if:
384 *
385 * - the broadcast device exists
386 * - the broadcast device is not a hrtimer based one
387 * - the broadcast device is in periodic mode to
388 * avoid a hickup during switch to oneshot mode
389 */
390 if (bc && !(bc->features & CLOCK_EVT_FEAT_HRTIMER) &&
391 tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
392 clockevents_shutdown(dev);
393 }
394 break;
395
396 case TICK_BROADCAST_OFF:
397 if (tick_broadcast_forced)
398 break;
399 cpumask_clear_cpu(cpu, tick_broadcast_on);
400 if (!tick_device_is_functional(dev))
401 break;
402 if (cpumask_test_and_clear_cpu(cpu, tick_broadcast_mask)) {
403 if (tick_broadcast_device.mode ==
404 TICKDEV_MODE_PERIODIC)
405 tick_setup_periodic(dev, 0);
406 }
407 break;
408 }
409
410 if (bc) {
411 if (cpumask_empty(tick_broadcast_mask)) {
412 if (!bc_stopped)
413 clockevents_shutdown(bc);
414 } else if (bc_stopped) {
415 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
416 tick_broadcast_start_periodic(bc);
417 else
418 tick_broadcast_setup_oneshot(bc);
419 }
420 }
421out:
422 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
423}
424EXPORT_SYMBOL_GPL(tick_broadcast_control);
425
426/*
427 * Set the periodic handler depending on broadcast on/off
428 */
429void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast)
430{
431 if (!broadcast)
432 dev->event_handler = tick_handle_periodic;
433 else
434 dev->event_handler = tick_handle_periodic_broadcast;
435}
436
437#ifdef CONFIG_HOTPLUG_CPU
438/*
439 * Remove a CPU from broadcasting
440 */
441void tick_shutdown_broadcast(unsigned int cpu)
442{
443 struct clock_event_device *bc;
444 unsigned long flags;
445
446 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
447
448 bc = tick_broadcast_device.evtdev;
449 cpumask_clear_cpu(cpu, tick_broadcast_mask);
450 cpumask_clear_cpu(cpu, tick_broadcast_on);
451
452 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
453 if (bc && cpumask_empty(tick_broadcast_mask))
454 clockevents_shutdown(bc);
455 }
456
457 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
458}
459#endif
460
461void tick_suspend_broadcast(void)
462{
463 struct clock_event_device *bc;
464 unsigned long flags;
465
466 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
467
468 bc = tick_broadcast_device.evtdev;
469 if (bc)
470 clockevents_shutdown(bc);
471
472 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
473}
474
475/*
476 * This is called from tick_resume_local() on a resuming CPU. That's
477 * called from the core resume function, tick_unfreeze() and the magic XEN
478 * resume hackery.
479 *
480 * In none of these cases the broadcast device mode can change and the
481 * bit of the resuming CPU in the broadcast mask is safe as well.
482 */
483bool tick_resume_check_broadcast(void)
484{
485 if (tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT)
486 return false;
487 else
488 return cpumask_test_cpu(smp_processor_id(), tick_broadcast_mask);
489}
490
491void tick_resume_broadcast(void)
492{
493 struct clock_event_device *bc;
494 unsigned long flags;
495
496 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
497
498 bc = tick_broadcast_device.evtdev;
499
500 if (bc) {
501 clockevents_tick_resume(bc);
502
503 switch (tick_broadcast_device.mode) {
504 case TICKDEV_MODE_PERIODIC:
505 if (!cpumask_empty(tick_broadcast_mask))
506 tick_broadcast_start_periodic(bc);
507 break;
508 case TICKDEV_MODE_ONESHOT:
509 if (!cpumask_empty(tick_broadcast_mask))
510 tick_resume_broadcast_oneshot(bc);
511 break;
512 }
513 }
514 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
515}
516
517#ifdef CONFIG_TICK_ONESHOT
518
519static cpumask_var_t tick_broadcast_oneshot_mask;
520static cpumask_var_t tick_broadcast_pending_mask;
521static cpumask_var_t tick_broadcast_force_mask;
522
523/*
524 * Exposed for debugging: see timer_list.c
525 */
526struct cpumask *tick_get_broadcast_oneshot_mask(void)
527{
528 return tick_broadcast_oneshot_mask;
529}
530
531/*
532 * Called before going idle with interrupts disabled. Checks whether a
533 * broadcast event from the other core is about to happen. We detected
534 * that in tick_broadcast_oneshot_control(). The callsite can use this
535 * to avoid a deep idle transition as we are about to get the
536 * broadcast IPI right away.
537 */
538int tick_check_broadcast_expired(void)
539{
540 return cpumask_test_cpu(smp_processor_id(), tick_broadcast_force_mask);
541}
542
543/*
544 * Set broadcast interrupt affinity
545 */
546static void tick_broadcast_set_affinity(struct clock_event_device *bc,
547 const struct cpumask *cpumask)
548{
549 if (!(bc->features & CLOCK_EVT_FEAT_DYNIRQ))
550 return;
551
552 if (cpumask_equal(bc->cpumask, cpumask))
553 return;
554
555 bc->cpumask = cpumask;
556 irq_set_affinity(bc->irq, bc->cpumask);
557}
558
559static void tick_broadcast_set_event(struct clock_event_device *bc, int cpu,
560 ktime_t expires)
561{
562 if (!clockevent_state_oneshot(bc))
563 clockevents_switch_state(bc, CLOCK_EVT_STATE_ONESHOT);
564
565 clockevents_program_event(bc, expires, 1);
566 tick_broadcast_set_affinity(bc, cpumask_of(cpu));
567}
568
569static void tick_resume_broadcast_oneshot(struct clock_event_device *bc)
570{
571 clockevents_switch_state(bc, CLOCK_EVT_STATE_ONESHOT);
572}
573
574/*
575 * Called from irq_enter() when idle was interrupted to reenable the
576 * per cpu device.
577 */
578void tick_check_oneshot_broadcast_this_cpu(void)
579{
580 if (cpumask_test_cpu(smp_processor_id(), tick_broadcast_oneshot_mask)) {
581 struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
582
583 /*
584 * We might be in the middle of switching over from
585 * periodic to oneshot. If the CPU has not yet
586 * switched over, leave the device alone.
587 */
588 if (td->mode == TICKDEV_MODE_ONESHOT) {
589 clockevents_switch_state(td->evtdev,
590 CLOCK_EVT_STATE_ONESHOT);
591 }
592 }
593}
594
595/*
596 * Handle oneshot mode broadcasting
597 */
598static void tick_handle_oneshot_broadcast(struct clock_event_device *dev)
599{
600 struct tick_device *td;
601 ktime_t now, next_event;
602 int cpu, next_cpu = 0;
603 bool bc_local;
604
605 raw_spin_lock(&tick_broadcast_lock);
606 dev->next_event = KTIME_MAX;
607 next_event = KTIME_MAX;
608 cpumask_clear(tmpmask);
609 now = ktime_get();
610 /* Find all expired events */
611 for_each_cpu(cpu, tick_broadcast_oneshot_mask) {
612 td = &per_cpu(tick_cpu_device, cpu);
613 if (td->evtdev->next_event <= now) {
614 cpumask_set_cpu(cpu, tmpmask);
615 /*
616 * Mark the remote cpu in the pending mask, so
617 * it can avoid reprogramming the cpu local
618 * timer in tick_broadcast_oneshot_control().
619 */
620 cpumask_set_cpu(cpu, tick_broadcast_pending_mask);
621 } else if (td->evtdev->next_event < next_event) {
622 next_event = td->evtdev->next_event;
623 next_cpu = cpu;
624 }
625 }
626
627 /*
628 * Remove the current cpu from the pending mask. The event is
629 * delivered immediately in tick_do_broadcast() !
630 */
631 cpumask_clear_cpu(smp_processor_id(), tick_broadcast_pending_mask);
632
633 /* Take care of enforced broadcast requests */
634 cpumask_or(tmpmask, tmpmask, tick_broadcast_force_mask);
635 cpumask_clear(tick_broadcast_force_mask);
636
637 /*
638 * Sanity check. Catch the case where we try to broadcast to
639 * offline cpus.
640 */
641 if (WARN_ON_ONCE(!cpumask_subset(tmpmask, cpu_online_mask)))
642 cpumask_and(tmpmask, tmpmask, cpu_online_mask);
643
644 /*
645 * Wakeup the cpus which have an expired event.
646 */
647 bc_local = tick_do_broadcast(tmpmask);
648
649 /*
650 * Two reasons for reprogram:
651 *
652 * - The global event did not expire any CPU local
653 * events. This happens in dyntick mode, as the maximum PIT
654 * delta is quite small.
655 *
656 * - There are pending events on sleeping CPUs which were not
657 * in the event mask
658 */
659 if (next_event != KTIME_MAX)
660 tick_broadcast_set_event(dev, next_cpu, next_event);
661
662 raw_spin_unlock(&tick_broadcast_lock);
663
664 if (bc_local) {
665 td = this_cpu_ptr(&tick_cpu_device);
666 td->evtdev->event_handler(td->evtdev);
667 }
668}
669
670static int broadcast_needs_cpu(struct clock_event_device *bc, int cpu)
671{
672 if (!(bc->features & CLOCK_EVT_FEAT_HRTIMER))
673 return 0;
674 if (bc->next_event == KTIME_MAX)
675 return 0;
676 return bc->bound_on == cpu ? -EBUSY : 0;
677}
678
679static void broadcast_shutdown_local(struct clock_event_device *bc,
680 struct clock_event_device *dev)
681{
682 /*
683 * For hrtimer based broadcasting we cannot shutdown the cpu
684 * local device if our own event is the first one to expire or
685 * if we own the broadcast timer.
686 */
687 if (bc->features & CLOCK_EVT_FEAT_HRTIMER) {
688 if (broadcast_needs_cpu(bc, smp_processor_id()))
689 return;
690 if (dev->next_event < bc->next_event)
691 return;
692 }
693 clockevents_switch_state(dev, CLOCK_EVT_STATE_SHUTDOWN);
694}
695
696int __tick_broadcast_oneshot_control(enum tick_broadcast_state state)
697{
698 struct clock_event_device *bc, *dev;
699 int cpu, ret = 0;
700 ktime_t now;
701
702 /*
703 * If there is no broadcast device, tell the caller not to go
704 * into deep idle.
705 */
706 if (!tick_broadcast_device.evtdev)
707 return -EBUSY;
708
709 dev = this_cpu_ptr(&tick_cpu_device)->evtdev;
710
711 raw_spin_lock(&tick_broadcast_lock);
712 bc = tick_broadcast_device.evtdev;
713 cpu = smp_processor_id();
714
715 if (state == TICK_BROADCAST_ENTER) {
716 /*
717 * If the current CPU owns the hrtimer broadcast
718 * mechanism, it cannot go deep idle and we do not add
719 * the CPU to the broadcast mask. We don't have to go
720 * through the EXIT path as the local timer is not
721 * shutdown.
722 */
723 ret = broadcast_needs_cpu(bc, cpu);
724 if (ret)
725 goto out;
726
727 /*
728 * If the broadcast device is in periodic mode, we
729 * return.
730 */
731 if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) {
732 /* If it is a hrtimer based broadcast, return busy */
733 if (bc->features & CLOCK_EVT_FEAT_HRTIMER)
734 ret = -EBUSY;
735 goto out;
736 }
737
738 if (!cpumask_test_and_set_cpu(cpu, tick_broadcast_oneshot_mask)) {
739 WARN_ON_ONCE(cpumask_test_cpu(cpu, tick_broadcast_pending_mask));
740
741 /* Conditionally shut down the local timer. */
742 broadcast_shutdown_local(bc, dev);
743
744 /*
745 * We only reprogram the broadcast timer if we
746 * did not mark ourself in the force mask and
747 * if the cpu local event is earlier than the
748 * broadcast event. If the current CPU is in
749 * the force mask, then we are going to be
750 * woken by the IPI right away; we return
751 * busy, so the CPU does not try to go deep
752 * idle.
753 */
754 if (cpumask_test_cpu(cpu, tick_broadcast_force_mask)) {
755 ret = -EBUSY;
756 } else if (dev->next_event < bc->next_event) {
757 tick_broadcast_set_event(bc, cpu, dev->next_event);
758 /*
759 * In case of hrtimer broadcasts the
760 * programming might have moved the
761 * timer to this cpu. If yes, remove
762 * us from the broadcast mask and
763 * return busy.
764 */
765 ret = broadcast_needs_cpu(bc, cpu);
766 if (ret) {
767 cpumask_clear_cpu(cpu,
768 tick_broadcast_oneshot_mask);
769 }
770 }
771 }
772 } else {
773 if (cpumask_test_and_clear_cpu(cpu, tick_broadcast_oneshot_mask)) {
774 clockevents_switch_state(dev, CLOCK_EVT_STATE_ONESHOT);
775 /*
776 * The cpu which was handling the broadcast
777 * timer marked this cpu in the broadcast
778 * pending mask and fired the broadcast
779 * IPI. So we are going to handle the expired
780 * event anyway via the broadcast IPI
781 * handler. No need to reprogram the timer
782 * with an already expired event.
783 */
784 if (cpumask_test_and_clear_cpu(cpu,
785 tick_broadcast_pending_mask))
786 goto out;
787
788 /*
789 * Bail out if there is no next event.
790 */
791 if (dev->next_event == KTIME_MAX)
792 goto out;
793 /*
794 * If the pending bit is not set, then we are
795 * either the CPU handling the broadcast
796 * interrupt or we got woken by something else.
797 *
798 * We are not longer in the broadcast mask, so
799 * if the cpu local expiry time is already
800 * reached, we would reprogram the cpu local
801 * timer with an already expired event.
802 *
803 * This can lead to a ping-pong when we return
804 * to idle and therefor rearm the broadcast
805 * timer before the cpu local timer was able
806 * to fire. This happens because the forced
807 * reprogramming makes sure that the event
808 * will happen in the future and depending on
809 * the min_delta setting this might be far
810 * enough out that the ping-pong starts.
811 *
812 * If the cpu local next_event has expired
813 * then we know that the broadcast timer
814 * next_event has expired as well and
815 * broadcast is about to be handled. So we
816 * avoid reprogramming and enforce that the
817 * broadcast handler, which did not run yet,
818 * will invoke the cpu local handler.
819 *
820 * We cannot call the handler directly from
821 * here, because we might be in a NOHZ phase
822 * and we did not go through the irq_enter()
823 * nohz fixups.
824 */
825 now = ktime_get();
826 if (dev->next_event <= now) {
827 cpumask_set_cpu(cpu, tick_broadcast_force_mask);
828 goto out;
829 }
830 /*
831 * We got woken by something else. Reprogram
832 * the cpu local timer device.
833 */
834 tick_program_event(dev->next_event, 1);
835 }
836 }
837out:
838 raw_spin_unlock(&tick_broadcast_lock);
839 return ret;
840}
841
842/*
843 * Reset the one shot broadcast for a cpu
844 *
845 * Called with tick_broadcast_lock held
846 */
847static void tick_broadcast_clear_oneshot(int cpu)
848{
849 cpumask_clear_cpu(cpu, tick_broadcast_oneshot_mask);
850 cpumask_clear_cpu(cpu, tick_broadcast_pending_mask);
851}
852
853static void tick_broadcast_init_next_event(struct cpumask *mask,
854 ktime_t expires)
855{
856 struct tick_device *td;
857 int cpu;
858
859 for_each_cpu(cpu, mask) {
860 td = &per_cpu(tick_cpu_device, cpu);
861 if (td->evtdev)
862 td->evtdev->next_event = expires;
863 }
864}
865
866/**
867 * tick_broadcast_setup_oneshot - setup the broadcast device
868 */
869void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
870{
871 int cpu = smp_processor_id();
872
873 if (!bc)
874 return;
875
876 /* Set it up only once ! */
877 if (bc->event_handler != tick_handle_oneshot_broadcast) {
878 int was_periodic = clockevent_state_periodic(bc);
879
880 bc->event_handler = tick_handle_oneshot_broadcast;
881
882 /*
883 * We must be careful here. There might be other CPUs
884 * waiting for periodic broadcast. We need to set the
885 * oneshot_mask bits for those and program the
886 * broadcast device to fire.
887 */
888 cpumask_copy(tmpmask, tick_broadcast_mask);
889 cpumask_clear_cpu(cpu, tmpmask);
890 cpumask_or(tick_broadcast_oneshot_mask,
891 tick_broadcast_oneshot_mask, tmpmask);
892
893 if (was_periodic && !cpumask_empty(tmpmask)) {
894 clockevents_switch_state(bc, CLOCK_EVT_STATE_ONESHOT);
895 tick_broadcast_init_next_event(tmpmask,
896 tick_next_period);
897 tick_broadcast_set_event(bc, cpu, tick_next_period);
898 } else
899 bc->next_event = KTIME_MAX;
900 } else {
901 /*
902 * The first cpu which switches to oneshot mode sets
903 * the bit for all other cpus which are in the general
904 * (periodic) broadcast mask. So the bit is set and
905 * would prevent the first broadcast enter after this
906 * to program the bc device.
907 */
908 tick_broadcast_clear_oneshot(cpu);
909 }
910}
911
912/*
913 * Select oneshot operating mode for the broadcast device
914 */
915void tick_broadcast_switch_to_oneshot(void)
916{
917 struct clock_event_device *bc;
918 unsigned long flags;
919
920 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
921
922 tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
923 bc = tick_broadcast_device.evtdev;
924 if (bc)
925 tick_broadcast_setup_oneshot(bc);
926
927 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
928}
929
930#ifdef CONFIG_HOTPLUG_CPU
931void hotplug_cpu__broadcast_tick_pull(int deadcpu)
932{
933 struct clock_event_device *bc;
934 unsigned long flags;
935
936 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
937 bc = tick_broadcast_device.evtdev;
938
939 if (bc && broadcast_needs_cpu(bc, deadcpu)) {
940 /* This moves the broadcast assignment to this CPU: */
941 clockevents_program_event(bc, bc->next_event, 1);
942 }
943 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
944}
945
946/*
947 * Remove a dead CPU from broadcasting
948 */
949void tick_shutdown_broadcast_oneshot(unsigned int cpu)
950{
951 unsigned long flags;
952
953 raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
954
955 /*
956 * Clear the broadcast masks for the dead cpu, but do not stop
957 * the broadcast device!
958 */
959 cpumask_clear_cpu(cpu, tick_broadcast_oneshot_mask);
960 cpumask_clear_cpu(cpu, tick_broadcast_pending_mask);
961 cpumask_clear_cpu(cpu, tick_broadcast_force_mask);
962
963 raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
964}
965#endif
966
967/*
968 * Check, whether the broadcast device is in one shot mode
969 */
970int tick_broadcast_oneshot_active(void)
971{
972 return tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT;
973}
974
975/*
976 * Check whether the broadcast device supports oneshot.
977 */
978bool tick_broadcast_oneshot_available(void)
979{
980 struct clock_event_device *bc = tick_broadcast_device.evtdev;
981
982 return bc ? bc->features & CLOCK_EVT_FEAT_ONESHOT : false;
983}
984
985#else
986int __tick_broadcast_oneshot_control(enum tick_broadcast_state state)
987{
988 struct clock_event_device *bc = tick_broadcast_device.evtdev;
989
990 if (!bc || (bc->features & CLOCK_EVT_FEAT_HRTIMER))
991 return -EBUSY;
992
993 return 0;
994}
995#endif
996
997void __init tick_broadcast_init(void)
998{
999 zalloc_cpumask_var(&tick_broadcast_mask, GFP_NOWAIT);
1000 zalloc_cpumask_var(&tick_broadcast_on, GFP_NOWAIT);
1001 zalloc_cpumask_var(&tmpmask, GFP_NOWAIT);
1002#ifdef CONFIG_TICK_ONESHOT
1003 zalloc_cpumask_var(&tick_broadcast_oneshot_mask, GFP_NOWAIT);
1004 zalloc_cpumask_var(&tick_broadcast_pending_mask, GFP_NOWAIT);
1005 zalloc_cpumask_var(&tick_broadcast_force_mask, GFP_NOWAIT);
1006#endif
1007}