projects/linux·blob v4.0-rc1 · refs

790 lines · 19.2 KiB

1/* CPU control.
2 * (C) 2001, 2002, 2003, 2004 Rusty Russell
3 *
4 * This code is licenced under the GPL.
5 */
6#include <linux/proc_fs.h>
7#include <linux/smp.h>
8#include <linux/init.h>
9#include <linux/notifier.h>
10#include <linux/sched.h>
11#include <linux/unistd.h>
12#include <linux/cpu.h>
13#include <linux/oom.h>
14#include <linux/rcupdate.h>
15#include <linux/export.h>
16#include <linux/bug.h>
17#include <linux/kthread.h>
18#include <linux/stop_machine.h>
19#include <linux/mutex.h>
20#include <linux/gfp.h>
21#include <linux/suspend.h>
22#include <linux/lockdep.h>
23#include <trace/events/power.h>
24
25#include "smpboot.h"
26
27#ifdef CONFIG_SMP
28/* Serializes the updates to cpu_online_mask, cpu_present_mask */
29static DEFINE_MUTEX(cpu_add_remove_lock);
30
31/*
32 * The following two APIs (cpu_maps_update_begin/done) must be used when
33 * attempting to serialize the updates to cpu_online_mask & cpu_present_mask.
34 * The APIs cpu_notifier_register_begin/done() must be used to protect CPU
35 * hotplug callback (un)registration performed using __register_cpu_notifier()
36 * or __unregister_cpu_notifier().
37 */
38void cpu_maps_update_begin(void)
39{
40 mutex_lock(&cpu_add_remove_lock);
41}
42EXPORT_SYMBOL(cpu_notifier_register_begin);
43
44void cpu_maps_update_done(void)
45{
46 mutex_unlock(&cpu_add_remove_lock);
47}
48EXPORT_SYMBOL(cpu_notifier_register_done);
49
50static RAW_NOTIFIER_HEAD(cpu_chain);
51
52/* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
53 * Should always be manipulated under cpu_add_remove_lock
54 */
55static int cpu_hotplug_disabled;
56
57#ifdef CONFIG_HOTPLUG_CPU
58
59static struct {
60 struct task_struct *active_writer;
61 /* wait queue to wake up the active_writer */
62 wait_queue_head_t wq;
63 /* verifies that no writer will get active while readers are active */
64 struct mutex lock;
65 /*
66 * Also blocks the new readers during
67 * an ongoing cpu hotplug operation.
68 */
69 atomic_t refcount;
70
71#ifdef CONFIG_DEBUG_LOCK_ALLOC
72 struct lockdep_map dep_map;
73#endif
74} cpu_hotplug = {
75 .active_writer = NULL,
76 .wq = __WAIT_QUEUE_HEAD_INITIALIZER(cpu_hotplug.wq),
77 .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),
78#ifdef CONFIG_DEBUG_LOCK_ALLOC
79 .dep_map = {.name = "cpu_hotplug.lock" },
80#endif
81};
82
83/* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */
84#define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map)
85#define cpuhp_lock_acquire_tryread() \
86 lock_map_acquire_tryread(&cpu_hotplug.dep_map)
87#define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map)
88#define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)
89
90
91void get_online_cpus(void)
92{
93 might_sleep();
94 if (cpu_hotplug.active_writer == current)
95 return;
96 cpuhp_lock_acquire_read();
97 mutex_lock(&cpu_hotplug.lock);
98 atomic_inc(&cpu_hotplug.refcount);
99 mutex_unlock(&cpu_hotplug.lock);
100}
101EXPORT_SYMBOL_GPL(get_online_cpus);
102
103bool try_get_online_cpus(void)
104{
105 if (cpu_hotplug.active_writer == current)
106 return true;
107 if (!mutex_trylock(&cpu_hotplug.lock))
108 return false;
109 cpuhp_lock_acquire_tryread();
110 atomic_inc(&cpu_hotplug.refcount);
111 mutex_unlock(&cpu_hotplug.lock);
112 return true;
113}
114EXPORT_SYMBOL_GPL(try_get_online_cpus);
115
116void put_online_cpus(void)
117{
118 int refcount;
119
120 if (cpu_hotplug.active_writer == current)
121 return;
122
123 refcount = atomic_dec_return(&cpu_hotplug.refcount);
124 if (WARN_ON(refcount < 0)) /* try to fix things up */
125 atomic_inc(&cpu_hotplug.refcount);
126
127 if (refcount <= 0 && waitqueue_active(&cpu_hotplug.wq))
128 wake_up(&cpu_hotplug.wq);
129
130 cpuhp_lock_release();
131
132}
133EXPORT_SYMBOL_GPL(put_online_cpus);
134
135/*
136 * This ensures that the hotplug operation can begin only when the
137 * refcount goes to zero.
138 *
139 * Note that during a cpu-hotplug operation, the new readers, if any,
140 * will be blocked by the cpu_hotplug.lock
141 *
142 * Since cpu_hotplug_begin() is always called after invoking
143 * cpu_maps_update_begin(), we can be sure that only one writer is active.
144 *
145 * Note that theoretically, there is a possibility of a livelock:
146 * - Refcount goes to zero, last reader wakes up the sleeping
147 * writer.
148 * - Last reader unlocks the cpu_hotplug.lock.
149 * - A new reader arrives at this moment, bumps up the refcount.
150 * - The writer acquires the cpu_hotplug.lock finds the refcount
151 * non zero and goes to sleep again.
152 *
153 * However, this is very difficult to achieve in practice since
154 * get_online_cpus() not an api which is called all that often.
155 *
156 */
157void cpu_hotplug_begin(void)
158{
159 DEFINE_WAIT(wait);
160
161 cpu_hotplug.active_writer = current;
162 cpuhp_lock_acquire();
163
164 for (;;) {
165 mutex_lock(&cpu_hotplug.lock);
166 prepare_to_wait(&cpu_hotplug.wq, &wait, TASK_UNINTERRUPTIBLE);
167 if (likely(!atomic_read(&cpu_hotplug.refcount)))
168 break;
169 mutex_unlock(&cpu_hotplug.lock);
170 schedule();
171 }
172 finish_wait(&cpu_hotplug.wq, &wait);
173}
174
175void cpu_hotplug_done(void)
176{
177 cpu_hotplug.active_writer = NULL;
178 mutex_unlock(&cpu_hotplug.lock);
179 cpuhp_lock_release();
180}
181
182/*
183 * Wait for currently running CPU hotplug operations to complete (if any) and
184 * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
185 * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the
186 * hotplug path before performing hotplug operations. So acquiring that lock
187 * guarantees mutual exclusion from any currently running hotplug operations.
188 */
189void cpu_hotplug_disable(void)
190{
191 cpu_maps_update_begin();
192 cpu_hotplug_disabled = 1;
193 cpu_maps_update_done();
194}
195
196void cpu_hotplug_enable(void)
197{
198 cpu_maps_update_begin();
199 cpu_hotplug_disabled = 0;
200 cpu_maps_update_done();
201}
202
203#endif /* CONFIG_HOTPLUG_CPU */
204
205/* Need to know about CPUs going up/down? */
206int __ref register_cpu_notifier(struct notifier_block *nb)
207{
208 int ret;
209 cpu_maps_update_begin();
210 ret = raw_notifier_chain_register(&cpu_chain, nb);
211 cpu_maps_update_done();
212 return ret;
213}
214
215int __ref __register_cpu_notifier(struct notifier_block *nb)
216{
217 return raw_notifier_chain_register(&cpu_chain, nb);
218}
219
220static int __cpu_notify(unsigned long val, void *v, int nr_to_call,
221 int *nr_calls)
222{
223 int ret;
224
225 ret = __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call,
226 nr_calls);
227
228 return notifier_to_errno(ret);
229}
230
231static int cpu_notify(unsigned long val, void *v)
232{
233 return __cpu_notify(val, v, -1, NULL);
234}
235
236#ifdef CONFIG_HOTPLUG_CPU
237
238static void cpu_notify_nofail(unsigned long val, void *v)
239{
240 BUG_ON(cpu_notify(val, v));
241}
242EXPORT_SYMBOL(register_cpu_notifier);
243EXPORT_SYMBOL(__register_cpu_notifier);
244
245void __ref unregister_cpu_notifier(struct notifier_block *nb)
246{
247 cpu_maps_update_begin();
248 raw_notifier_chain_unregister(&cpu_chain, nb);
249 cpu_maps_update_done();
250}
251EXPORT_SYMBOL(unregister_cpu_notifier);
252
253void __ref __unregister_cpu_notifier(struct notifier_block *nb)
254{
255 raw_notifier_chain_unregister(&cpu_chain, nb);
256}
257EXPORT_SYMBOL(__unregister_cpu_notifier);
258
259/**
260 * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
261 * @cpu: a CPU id
262 *
263 * This function walks all processes, finds a valid mm struct for each one and
264 * then clears a corresponding bit in mm's cpumask. While this all sounds
265 * trivial, there are various non-obvious corner cases, which this function
266 * tries to solve in a safe manner.
267 *
268 * Also note that the function uses a somewhat relaxed locking scheme, so it may
269 * be called only for an already offlined CPU.
270 */
271void clear_tasks_mm_cpumask(int cpu)
272{
273 struct task_struct *p;
274
275 /*
276 * This function is called after the cpu is taken down and marked
277 * offline, so its not like new tasks will ever get this cpu set in
278 * their mm mask. -- Peter Zijlstra
279 * Thus, we may use rcu_read_lock() here, instead of grabbing
280 * full-fledged tasklist_lock.
281 */
282 WARN_ON(cpu_online(cpu));
283 rcu_read_lock();
284 for_each_process(p) {
285 struct task_struct *t;
286
287 /*
288 * Main thread might exit, but other threads may still have
289 * a valid mm. Find one.
290 */
291 t = find_lock_task_mm(p);
292 if (!t)
293 continue;
294 cpumask_clear_cpu(cpu, mm_cpumask(t->mm));
295 task_unlock(t);
296 }
297 rcu_read_unlock();
298}
299
300static inline void check_for_tasks(int dead_cpu)
301{
302 struct task_struct *g, *p;
303
304 read_lock_irq(&tasklist_lock);
305 do_each_thread(g, p) {
306 if (!p->on_rq)
307 continue;
308 /*
309 * We do the check with unlocked task_rq(p)->lock.
310 * Order the reading to do not warn about a task,
311 * which was running on this cpu in the past, and
312 * it's just been woken on another cpu.
313 */
314 rmb();
315 if (task_cpu(p) != dead_cpu)
316 continue;
317
318 pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n",
319 p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags);
320 } while_each_thread(g, p);
321 read_unlock_irq(&tasklist_lock);
322}
323
324struct take_cpu_down_param {
325 unsigned long mod;
326 void *hcpu;
327};
328
329/* Take this CPU down. */
330static int __ref take_cpu_down(void *_param)
331{
332 struct take_cpu_down_param *param = _param;
333 int err;
334
335 /* Ensure this CPU doesn't handle any more interrupts. */
336 err = __cpu_disable();
337 if (err < 0)
338 return err;
339
340 cpu_notify(CPU_DYING | param->mod, param->hcpu);
341 /* Park the stopper thread */
342 kthread_park(current);
343 return 0;
344}
345
346/* Requires cpu_add_remove_lock to be held */
347static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
348{
349 int err, nr_calls = 0;
350 void *hcpu = (void *)(long)cpu;
351 unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
352 struct take_cpu_down_param tcd_param = {
353 .mod = mod,
354 .hcpu = hcpu,
355 };
356
357 if (num_online_cpus() == 1)
358 return -EBUSY;
359
360 if (!cpu_online(cpu))
361 return -EINVAL;
362
363 cpu_hotplug_begin();
364
365 err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls);
366 if (err) {
367 nr_calls--;
368 __cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL);
369 pr_warn("%s: attempt to take down CPU %u failed\n",
370 __func__, cpu);
371 goto out_release;
372 }
373
374 /*
375 * By now we've cleared cpu_active_mask, wait for all preempt-disabled
376 * and RCU users of this state to go away such that all new such users
377 * will observe it.
378 *
379 * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might
380 * not imply sync_sched(), so explicitly call both.
381 *
382 * Do sync before park smpboot threads to take care the rcu boost case.
383 */
384#ifdef CONFIG_PREEMPT
385 synchronize_sched();
386#endif
387 synchronize_rcu();
388
389 smpboot_park_threads(cpu);
390
391 /*
392 * So now all preempt/rcu users must observe !cpu_active().
393 */
394
395 err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu));
396 if (err) {
397 /* CPU didn't die: tell everyone. Can't complain. */
398 smpboot_unpark_threads(cpu);
399 cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu);
400 goto out_release;
401 }
402 BUG_ON(cpu_online(cpu));
403
404 /*
405 * The migration_call() CPU_DYING callback will have removed all
406 * runnable tasks from the cpu, there's only the idle task left now
407 * that the migration thread is done doing the stop_machine thing.
408 *
409 * Wait for the stop thread to go away.
410 */
411 while (!idle_cpu(cpu))
412 cpu_relax();
413
414 /* This actually kills the CPU. */
415 __cpu_die(cpu);
416
417 /* CPU is completely dead: tell everyone. Too late to complain. */
418 cpu_notify_nofail(CPU_DEAD | mod, hcpu);
419
420 check_for_tasks(cpu);
421
422out_release:
423 cpu_hotplug_done();
424 if (!err)
425 cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu);
426 return err;
427}
428
429int __ref cpu_down(unsigned int cpu)
430{
431 int err;
432
433 cpu_maps_update_begin();
434
435 if (cpu_hotplug_disabled) {
436 err = -EBUSY;
437 goto out;
438 }
439
440 err = _cpu_down(cpu, 0);
441
442out:
443 cpu_maps_update_done();
444 return err;
445}
446EXPORT_SYMBOL(cpu_down);
447#endif /*CONFIG_HOTPLUG_CPU*/
448
449/* Requires cpu_add_remove_lock to be held */
450static int _cpu_up(unsigned int cpu, int tasks_frozen)
451{
452 int ret, nr_calls = 0;
453 void *hcpu = (void *)(long)cpu;
454 unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
455 struct task_struct *idle;
456
457 cpu_hotplug_begin();
458
459 if (cpu_online(cpu) || !cpu_present(cpu)) {
460 ret = -EINVAL;
461 goto out;
462 }
463
464 idle = idle_thread_get(cpu);
465 if (IS_ERR(idle)) {
466 ret = PTR_ERR(idle);
467 goto out;
468 }
469
470 ret = smpboot_create_threads(cpu);
471 if (ret)
472 goto out;
473
474 ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls);
475 if (ret) {
476 nr_calls--;
477 pr_warn("%s: attempt to bring up CPU %u failed\n",
478 __func__, cpu);
479 goto out_notify;
480 }
481
482 /* Arch-specific enabling code. */
483 ret = __cpu_up(cpu, idle);
484 if (ret != 0)
485 goto out_notify;
486 BUG_ON(!cpu_online(cpu));
487
488 /* Wake the per cpu threads */
489 smpboot_unpark_threads(cpu);
490
491 /* Now call notifier in preparation. */
492 cpu_notify(CPU_ONLINE | mod, hcpu);
493
494out_notify:
495 if (ret != 0)
496 __cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);
497out:
498 cpu_hotplug_done();
499
500 return ret;
501}
502
503int cpu_up(unsigned int cpu)
504{
505 int err = 0;
506
507 if (!cpu_possible(cpu)) {
508 pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n",
509 cpu);
510#if defined(CONFIG_IA64)
511 pr_err("please check additional_cpus= boot parameter\n");
512#endif
513 return -EINVAL;
514 }
515
516 err = try_online_node(cpu_to_node(cpu));
517 if (err)
518 return err;
519
520 cpu_maps_update_begin();
521
522 if (cpu_hotplug_disabled) {
523 err = -EBUSY;
524 goto out;
525 }
526
527 err = _cpu_up(cpu, 0);
528
529out:
530 cpu_maps_update_done();
531 return err;
532}
533EXPORT_SYMBOL_GPL(cpu_up);
534
535#ifdef CONFIG_PM_SLEEP_SMP
536static cpumask_var_t frozen_cpus;
537
538int disable_nonboot_cpus(void)
539{
540 int cpu, first_cpu, error = 0;
541
542 cpu_maps_update_begin();
543 first_cpu = cpumask_first(cpu_online_mask);
544 /*
545 * We take down all of the non-boot CPUs in one shot to avoid races
546 * with the userspace trying to use the CPU hotplug at the same time
547 */
548 cpumask_clear(frozen_cpus);
549
550 pr_info("Disabling non-boot CPUs ...\n");
551 for_each_online_cpu(cpu) {
552 if (cpu == first_cpu)
553 continue;
554 trace_suspend_resume(TPS("CPU_OFF"), cpu, true);
555 error = _cpu_down(cpu, 1);
556 trace_suspend_resume(TPS("CPU_OFF"), cpu, false);
557 if (!error)
558 cpumask_set_cpu(cpu, frozen_cpus);
559 else {
560 pr_err("Error taking CPU%d down: %d\n", cpu, error);
561 break;
562 }
563 }
564
565 if (!error) {
566 BUG_ON(num_online_cpus() > 1);
567 /* Make sure the CPUs won't be enabled by someone else */
568 cpu_hotplug_disabled = 1;
569 } else {
570 pr_err("Non-boot CPUs are not disabled\n");
571 }
572 cpu_maps_update_done();
573 return error;
574}
575
576void __weak arch_enable_nonboot_cpus_begin(void)
577{
578}
579
580void __weak arch_enable_nonboot_cpus_end(void)
581{
582}
583
584void __ref enable_nonboot_cpus(void)
585{
586 int cpu, error;
587
588 /* Allow everyone to use the CPU hotplug again */
589 cpu_maps_update_begin();
590 cpu_hotplug_disabled = 0;
591 if (cpumask_empty(frozen_cpus))
592 goto out;
593
594 pr_info("Enabling non-boot CPUs ...\n");
595
596 arch_enable_nonboot_cpus_begin();
597
598 for_each_cpu(cpu, frozen_cpus) {
599 trace_suspend_resume(TPS("CPU_ON"), cpu, true);
600 error = _cpu_up(cpu, 1);
601 trace_suspend_resume(TPS("CPU_ON"), cpu, false);
602 if (!error) {
603 pr_info("CPU%d is up\n", cpu);
604 continue;
605 }
606 pr_warn("Error taking CPU%d up: %d\n", cpu, error);
607 }
608
609 arch_enable_nonboot_cpus_end();
610
611 cpumask_clear(frozen_cpus);
612out:
613 cpu_maps_update_done();
614}
615
616static int __init alloc_frozen_cpus(void)
617{
618 if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO))
619 return -ENOMEM;
620 return 0;
621}
622core_initcall(alloc_frozen_cpus);
623
624/*
625 * When callbacks for CPU hotplug notifications are being executed, we must
626 * ensure that the state of the system with respect to the tasks being frozen
627 * or not, as reported by the notification, remains unchanged *throughout the
628 * duration* of the execution of the callbacks.
629 * Hence we need to prevent the freezer from racing with regular CPU hotplug.
630 *
631 * This synchronization is implemented by mutually excluding regular CPU
632 * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
633 * Hibernate notifications.
634 */
635static int
636cpu_hotplug_pm_callback(struct notifier_block *nb,
637 unsigned long action, void *ptr)
638{
639 switch (action) {
640
641 case PM_SUSPEND_PREPARE:
642 case PM_HIBERNATION_PREPARE:
643 cpu_hotplug_disable();
644 break;
645
646 case PM_POST_SUSPEND:
647 case PM_POST_HIBERNATION:
648 cpu_hotplug_enable();
649 break;
650
651 default:
652 return NOTIFY_DONE;
653 }
654
655 return NOTIFY_OK;
656}
657
658
659static int __init cpu_hotplug_pm_sync_init(void)
660{
661 /*
662 * cpu_hotplug_pm_callback has higher priority than x86
663 * bsp_pm_callback which depends on cpu_hotplug_pm_callback
664 * to disable cpu hotplug to avoid cpu hotplug race.
665 */
666 pm_notifier(cpu_hotplug_pm_callback, 0);
667 return 0;
668}
669core_initcall(cpu_hotplug_pm_sync_init);
670
671#endif /* CONFIG_PM_SLEEP_SMP */
672
673/**
674 * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
675 * @cpu: cpu that just started
676 *
677 * This function calls the cpu_chain notifiers with CPU_STARTING.
678 * It must be called by the arch code on the new cpu, before the new cpu
679 * enables interrupts and before the "boot" cpu returns from __cpu_up().
680 */
681void notify_cpu_starting(unsigned int cpu)
682{
683 unsigned long val = CPU_STARTING;
684
685#ifdef CONFIG_PM_SLEEP_SMP
686 if (frozen_cpus != NULL && cpumask_test_cpu(cpu, frozen_cpus))
687 val = CPU_STARTING_FROZEN;
688#endif /* CONFIG_PM_SLEEP_SMP */
689 cpu_notify(val, (void *)(long)cpu);
690}
691
692#endif /* CONFIG_SMP */
693
694/*
695 * cpu_bit_bitmap[] is a special, "compressed" data structure that
696 * represents all NR_CPUS bits binary values of 1<<nr.
697 *
698 * It is used by cpumask_of() to get a constant address to a CPU
699 * mask value that has a single bit set only.
700 */
701
702/* cpu_bit_bitmap[0] is empty - so we can back into it */
703#define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x))
704#define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1)
705#define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2)
706#define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4)
707
708const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = {
709
710 MASK_DECLARE_8(0), MASK_DECLARE_8(8),
711 MASK_DECLARE_8(16), MASK_DECLARE_8(24),
712#if BITS_PER_LONG > 32
713 MASK_DECLARE_8(32), MASK_DECLARE_8(40),
714 MASK_DECLARE_8(48), MASK_DECLARE_8(56),
715#endif
716};
717EXPORT_SYMBOL_GPL(cpu_bit_bitmap);
718
719const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
720EXPORT_SYMBOL(cpu_all_bits);
721
722#ifdef CONFIG_INIT_ALL_POSSIBLE
723static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly
724 = CPU_BITS_ALL;
725#else
726static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly;
727#endif
728const struct cpumask *const cpu_possible_mask = to_cpumask(cpu_possible_bits);
729EXPORT_SYMBOL(cpu_possible_mask);
730
731static DECLARE_BITMAP(cpu_online_bits, CONFIG_NR_CPUS) __read_mostly;
732const struct cpumask *const cpu_online_mask = to_cpumask(cpu_online_bits);
733EXPORT_SYMBOL(cpu_online_mask);
734
735static DECLARE_BITMAP(cpu_present_bits, CONFIG_NR_CPUS) __read_mostly;
736const struct cpumask *const cpu_present_mask = to_cpumask(cpu_present_bits);
737EXPORT_SYMBOL(cpu_present_mask);
738
739static DECLARE_BITMAP(cpu_active_bits, CONFIG_NR_CPUS) __read_mostly;
740const struct cpumask *const cpu_active_mask = to_cpumask(cpu_active_bits);
741EXPORT_SYMBOL(cpu_active_mask);
742
743void set_cpu_possible(unsigned int cpu, bool possible)
744{
745 if (possible)
746 cpumask_set_cpu(cpu, to_cpumask(cpu_possible_bits));
747 else
748 cpumask_clear_cpu(cpu, to_cpumask(cpu_possible_bits));
749}
750
751void set_cpu_present(unsigned int cpu, bool present)
752{
753 if (present)
754 cpumask_set_cpu(cpu, to_cpumask(cpu_present_bits));
755 else
756 cpumask_clear_cpu(cpu, to_cpumask(cpu_present_bits));
757}
758
759void set_cpu_online(unsigned int cpu, bool online)
760{
761 if (online) {
762 cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits));
763 cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits));
764 } else {
765 cpumask_clear_cpu(cpu, to_cpumask(cpu_online_bits));
766 }
767}
768
769void set_cpu_active(unsigned int cpu, bool active)
770{
771 if (active)
772 cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits));
773 else
774 cpumask_clear_cpu(cpu, to_cpumask(cpu_active_bits));
775}
776
777void init_cpu_present(const struct cpumask *src)
778{
779 cpumask_copy(to_cpumask(cpu_present_bits), src);
780}
781
782void init_cpu_possible(const struct cpumask *src)
783{
784 cpumask_copy(to_cpumask(cpu_possible_bits), src);
785}
786
787void init_cpu_online(const struct cpumask *src)
788{
789 cpumask_copy(to_cpumask(cpu_online_bits), src);
790}