projects/linux·blob v3.18-rc2 · refs

781 lines · 19.0 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 struct mutex lock; /* Synchronizes accesses to refcount, */
62 /*
63 * Also blocks the new readers during
64 * an ongoing cpu hotplug operation.
65 */
66 int refcount;
67
68#ifdef CONFIG_DEBUG_LOCK_ALLOC
69 struct lockdep_map dep_map;
70#endif
71} cpu_hotplug = {
72 .active_writer = NULL,
73 .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),
74 .refcount = 0,
75#ifdef CONFIG_DEBUG_LOCK_ALLOC
76 .dep_map = {.name = "cpu_hotplug.lock" },
77#endif
78};
79
80/* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */
81#define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map)
82#define cpuhp_lock_acquire_tryread() \
83 lock_map_acquire_tryread(&cpu_hotplug.dep_map)
84#define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map)
85#define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)
86
87void get_online_cpus(void)
88{
89 might_sleep();
90 if (cpu_hotplug.active_writer == current)
91 return;
92 cpuhp_lock_acquire_read();
93 mutex_lock(&cpu_hotplug.lock);
94 cpu_hotplug.refcount++;
95 mutex_unlock(&cpu_hotplug.lock);
96}
97EXPORT_SYMBOL_GPL(get_online_cpus);
98
99bool try_get_online_cpus(void)
100{
101 if (cpu_hotplug.active_writer == current)
102 return true;
103 if (!mutex_trylock(&cpu_hotplug.lock))
104 return false;
105 cpuhp_lock_acquire_tryread();
106 cpu_hotplug.refcount++;
107 mutex_unlock(&cpu_hotplug.lock);
108 return true;
109}
110EXPORT_SYMBOL_GPL(try_get_online_cpus);
111
112void put_online_cpus(void)
113{
114 if (cpu_hotplug.active_writer == current)
115 return;
116 mutex_lock(&cpu_hotplug.lock);
117
118 if (WARN_ON(!cpu_hotplug.refcount))
119 cpu_hotplug.refcount++; /* try to fix things up */
120
121 if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer))
122 wake_up_process(cpu_hotplug.active_writer);
123 mutex_unlock(&cpu_hotplug.lock);
124 cpuhp_lock_release();
125
126}
127EXPORT_SYMBOL_GPL(put_online_cpus);
128
129/*
130 * This ensures that the hotplug operation can begin only when the
131 * refcount goes to zero.
132 *
133 * Note that during a cpu-hotplug operation, the new readers, if any,
134 * will be blocked by the cpu_hotplug.lock
135 *
136 * Since cpu_hotplug_begin() is always called after invoking
137 * cpu_maps_update_begin(), we can be sure that only one writer is active.
138 *
139 * Note that theoretically, there is a possibility of a livelock:
140 * - Refcount goes to zero, last reader wakes up the sleeping
141 * writer.
142 * - Last reader unlocks the cpu_hotplug.lock.
143 * - A new reader arrives at this moment, bumps up the refcount.
144 * - The writer acquires the cpu_hotplug.lock finds the refcount
145 * non zero and goes to sleep again.
146 *
147 * However, this is very difficult to achieve in practice since
148 * get_online_cpus() not an api which is called all that often.
149 *
150 */
151void cpu_hotplug_begin(void)
152{
153 cpu_hotplug.active_writer = current;
154
155 cpuhp_lock_acquire();
156 for (;;) {
157 mutex_lock(&cpu_hotplug.lock);
158 if (likely(!cpu_hotplug.refcount))
159 break;
160 __set_current_state(TASK_UNINTERRUPTIBLE);
161 mutex_unlock(&cpu_hotplug.lock);
162 schedule();
163 }
164}
165
166void cpu_hotplug_done(void)
167{
168 cpu_hotplug.active_writer = NULL;
169 mutex_unlock(&cpu_hotplug.lock);
170 cpuhp_lock_release();
171}
172
173/*
174 * Wait for currently running CPU hotplug operations to complete (if any) and
175 * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
176 * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the
177 * hotplug path before performing hotplug operations. So acquiring that lock
178 * guarantees mutual exclusion from any currently running hotplug operations.
179 */
180void cpu_hotplug_disable(void)
181{
182 cpu_maps_update_begin();
183 cpu_hotplug_disabled = 1;
184 cpu_maps_update_done();
185}
186
187void cpu_hotplug_enable(void)
188{
189 cpu_maps_update_begin();
190 cpu_hotplug_disabled = 0;
191 cpu_maps_update_done();
192}
193
194#endif /* CONFIG_HOTPLUG_CPU */
195
196/* Need to know about CPUs going up/down? */
197int __ref register_cpu_notifier(struct notifier_block *nb)
198{
199 int ret;
200 cpu_maps_update_begin();
201 ret = raw_notifier_chain_register(&cpu_chain, nb);
202 cpu_maps_update_done();
203 return ret;
204}
205
206int __ref __register_cpu_notifier(struct notifier_block *nb)
207{
208 return raw_notifier_chain_register(&cpu_chain, nb);
209}
210
211static int __cpu_notify(unsigned long val, void *v, int nr_to_call,
212 int *nr_calls)
213{
214 int ret;
215
216 ret = __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call,
217 nr_calls);
218
219 return notifier_to_errno(ret);
220}
221
222static int cpu_notify(unsigned long val, void *v)
223{
224 return __cpu_notify(val, v, -1, NULL);
225}
226
227#ifdef CONFIG_HOTPLUG_CPU
228
229static void cpu_notify_nofail(unsigned long val, void *v)
230{
231 BUG_ON(cpu_notify(val, v));
232}
233EXPORT_SYMBOL(register_cpu_notifier);
234EXPORT_SYMBOL(__register_cpu_notifier);
235
236void __ref unregister_cpu_notifier(struct notifier_block *nb)
237{
238 cpu_maps_update_begin();
239 raw_notifier_chain_unregister(&cpu_chain, nb);
240 cpu_maps_update_done();
241}
242EXPORT_SYMBOL(unregister_cpu_notifier);
243
244void __ref __unregister_cpu_notifier(struct notifier_block *nb)
245{
246 raw_notifier_chain_unregister(&cpu_chain, nb);
247}
248EXPORT_SYMBOL(__unregister_cpu_notifier);
249
250/**
251 * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
252 * @cpu: a CPU id
253 *
254 * This function walks all processes, finds a valid mm struct for each one and
255 * then clears a corresponding bit in mm's cpumask. While this all sounds
256 * trivial, there are various non-obvious corner cases, which this function
257 * tries to solve in a safe manner.
258 *
259 * Also note that the function uses a somewhat relaxed locking scheme, so it may
260 * be called only for an already offlined CPU.
261 */
262void clear_tasks_mm_cpumask(int cpu)
263{
264 struct task_struct *p;
265
266 /*
267 * This function is called after the cpu is taken down and marked
268 * offline, so its not like new tasks will ever get this cpu set in
269 * their mm mask. -- Peter Zijlstra
270 * Thus, we may use rcu_read_lock() here, instead of grabbing
271 * full-fledged tasklist_lock.
272 */
273 WARN_ON(cpu_online(cpu));
274 rcu_read_lock();
275 for_each_process(p) {
276 struct task_struct *t;
277
278 /*
279 * Main thread might exit, but other threads may still have
280 * a valid mm. Find one.
281 */
282 t = find_lock_task_mm(p);
283 if (!t)
284 continue;
285 cpumask_clear_cpu(cpu, mm_cpumask(t->mm));
286 task_unlock(t);
287 }
288 rcu_read_unlock();
289}
290
291static inline void check_for_tasks(int dead_cpu)
292{
293 struct task_struct *g, *p;
294
295 read_lock_irq(&tasklist_lock);
296 do_each_thread(g, p) {
297 if (!p->on_rq)
298 continue;
299 /*
300 * We do the check with unlocked task_rq(p)->lock.
301 * Order the reading to do not warn about a task,
302 * which was running on this cpu in the past, and
303 * it's just been woken on another cpu.
304 */
305 rmb();
306 if (task_cpu(p) != dead_cpu)
307 continue;
308
309 pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n",
310 p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags);
311 } while_each_thread(g, p);
312 read_unlock_irq(&tasklist_lock);
313}
314
315struct take_cpu_down_param {
316 unsigned long mod;
317 void *hcpu;
318};
319
320/* Take this CPU down. */
321static int __ref take_cpu_down(void *_param)
322{
323 struct take_cpu_down_param *param = _param;
324 int err;
325
326 /* Ensure this CPU doesn't handle any more interrupts. */
327 err = __cpu_disable();
328 if (err < 0)
329 return err;
330
331 cpu_notify(CPU_DYING | param->mod, param->hcpu);
332 /* Park the stopper thread */
333 kthread_park(current);
334 return 0;
335}
336
337/* Requires cpu_add_remove_lock to be held */
338static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
339{
340 int err, nr_calls = 0;
341 void *hcpu = (void *)(long)cpu;
342 unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
343 struct take_cpu_down_param tcd_param = {
344 .mod = mod,
345 .hcpu = hcpu,
346 };
347
348 if (num_online_cpus() == 1)
349 return -EBUSY;
350
351 if (!cpu_online(cpu))
352 return -EINVAL;
353
354 cpu_hotplug_begin();
355
356 err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls);
357 if (err) {
358 nr_calls--;
359 __cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL);
360 pr_warn("%s: attempt to take down CPU %u failed\n",
361 __func__, cpu);
362 goto out_release;
363 }
364
365 /*
366 * By now we've cleared cpu_active_mask, wait for all preempt-disabled
367 * and RCU users of this state to go away such that all new such users
368 * will observe it.
369 *
370 * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might
371 * not imply sync_sched(), so explicitly call both.
372 *
373 * Do sync before park smpboot threads to take care the rcu boost case.
374 */
375#ifdef CONFIG_PREEMPT
376 synchronize_sched();
377#endif
378 synchronize_rcu();
379
380 smpboot_park_threads(cpu);
381
382 /*
383 * So now all preempt/rcu users must observe !cpu_active().
384 */
385
386 err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu));
387 if (err) {
388 /* CPU didn't die: tell everyone. Can't complain. */
389 smpboot_unpark_threads(cpu);
390 cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu);
391 goto out_release;
392 }
393 BUG_ON(cpu_online(cpu));
394
395 /*
396 * The migration_call() CPU_DYING callback will have removed all
397 * runnable tasks from the cpu, there's only the idle task left now
398 * that the migration thread is done doing the stop_machine thing.
399 *
400 * Wait for the stop thread to go away.
401 */
402 while (!idle_cpu(cpu))
403 cpu_relax();
404
405 /* This actually kills the CPU. */
406 __cpu_die(cpu);
407
408 /* CPU is completely dead: tell everyone. Too late to complain. */
409 cpu_notify_nofail(CPU_DEAD | mod, hcpu);
410
411 check_for_tasks(cpu);
412
413out_release:
414 cpu_hotplug_done();
415 if (!err)
416 cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu);
417 return err;
418}
419
420int __ref cpu_down(unsigned int cpu)
421{
422 int err;
423
424 cpu_maps_update_begin();
425
426 if (cpu_hotplug_disabled) {
427 err = -EBUSY;
428 goto out;
429 }
430
431 err = _cpu_down(cpu, 0);
432
433out:
434 cpu_maps_update_done();
435 return err;
436}
437EXPORT_SYMBOL(cpu_down);
438#endif /*CONFIG_HOTPLUG_CPU*/
439
440/* Requires cpu_add_remove_lock to be held */
441static int _cpu_up(unsigned int cpu, int tasks_frozen)
442{
443 int ret, nr_calls = 0;
444 void *hcpu = (void *)(long)cpu;
445 unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
446 struct task_struct *idle;
447
448 cpu_hotplug_begin();
449
450 if (cpu_online(cpu) || !cpu_present(cpu)) {
451 ret = -EINVAL;
452 goto out;
453 }
454
455 idle = idle_thread_get(cpu);
456 if (IS_ERR(idle)) {
457 ret = PTR_ERR(idle);
458 goto out;
459 }
460
461 ret = smpboot_create_threads(cpu);
462 if (ret)
463 goto out;
464
465 ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls);
466 if (ret) {
467 nr_calls--;
468 pr_warn("%s: attempt to bring up CPU %u failed\n",
469 __func__, cpu);
470 goto out_notify;
471 }
472
473 /* Arch-specific enabling code. */
474 ret = __cpu_up(cpu, idle);
475 if (ret != 0)
476 goto out_notify;
477 BUG_ON(!cpu_online(cpu));
478
479 /* Wake the per cpu threads */
480 smpboot_unpark_threads(cpu);
481
482 /* Now call notifier in preparation. */
483 cpu_notify(CPU_ONLINE | mod, hcpu);
484
485out_notify:
486 if (ret != 0)
487 __cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);
488out:
489 cpu_hotplug_done();
490
491 return ret;
492}
493
494int cpu_up(unsigned int cpu)
495{
496 int err = 0;
497
498 if (!cpu_possible(cpu)) {
499 pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n",
500 cpu);
501#if defined(CONFIG_IA64)
502 pr_err("please check additional_cpus= boot parameter\n");
503#endif
504 return -EINVAL;
505 }
506
507 err = try_online_node(cpu_to_node(cpu));
508 if (err)
509 return err;
510
511 cpu_maps_update_begin();
512
513 if (cpu_hotplug_disabled) {
514 err = -EBUSY;
515 goto out;
516 }
517
518 err = _cpu_up(cpu, 0);
519
520out:
521 cpu_maps_update_done();
522 return err;
523}
524EXPORT_SYMBOL_GPL(cpu_up);
525
526#ifdef CONFIG_PM_SLEEP_SMP
527static cpumask_var_t frozen_cpus;
528
529int disable_nonboot_cpus(void)
530{
531 int cpu, first_cpu, error = 0;
532
533 cpu_maps_update_begin();
534 first_cpu = cpumask_first(cpu_online_mask);
535 /*
536 * We take down all of the non-boot CPUs in one shot to avoid races
537 * with the userspace trying to use the CPU hotplug at the same time
538 */
539 cpumask_clear(frozen_cpus);
540
541 pr_info("Disabling non-boot CPUs ...\n");
542 for_each_online_cpu(cpu) {
543 if (cpu == first_cpu)
544 continue;
545 trace_suspend_resume(TPS("CPU_OFF"), cpu, true);
546 error = _cpu_down(cpu, 1);
547 trace_suspend_resume(TPS("CPU_OFF"), cpu, false);
548 if (!error)
549 cpumask_set_cpu(cpu, frozen_cpus);
550 else {
551 pr_err("Error taking CPU%d down: %d\n", cpu, error);
552 break;
553 }
554 }
555
556 if (!error) {
557 BUG_ON(num_online_cpus() > 1);
558 /* Make sure the CPUs won't be enabled by someone else */
559 cpu_hotplug_disabled = 1;
560 } else {
561 pr_err("Non-boot CPUs are not disabled\n");
562 }
563 cpu_maps_update_done();
564 return error;
565}
566
567void __weak arch_enable_nonboot_cpus_begin(void)
568{
569}
570
571void __weak arch_enable_nonboot_cpus_end(void)
572{
573}
574
575void __ref enable_nonboot_cpus(void)
576{
577 int cpu, error;
578
579 /* Allow everyone to use the CPU hotplug again */
580 cpu_maps_update_begin();
581 cpu_hotplug_disabled = 0;
582 if (cpumask_empty(frozen_cpus))
583 goto out;
584
585 pr_info("Enabling non-boot CPUs ...\n");
586
587 arch_enable_nonboot_cpus_begin();
588
589 for_each_cpu(cpu, frozen_cpus) {
590 trace_suspend_resume(TPS("CPU_ON"), cpu, true);
591 error = _cpu_up(cpu, 1);
592 trace_suspend_resume(TPS("CPU_ON"), cpu, false);
593 if (!error) {
594 pr_info("CPU%d is up\n", cpu);
595 continue;
596 }
597 pr_warn("Error taking CPU%d up: %d\n", cpu, error);
598 }
599
600 arch_enable_nonboot_cpus_end();
601
602 cpumask_clear(frozen_cpus);
603out:
604 cpu_maps_update_done();
605}
606
607static int __init alloc_frozen_cpus(void)
608{
609 if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO))
610 return -ENOMEM;
611 return 0;
612}
613core_initcall(alloc_frozen_cpus);
614
615/*
616 * When callbacks for CPU hotplug notifications are being executed, we must
617 * ensure that the state of the system with respect to the tasks being frozen
618 * or not, as reported by the notification, remains unchanged *throughout the
619 * duration* of the execution of the callbacks.
620 * Hence we need to prevent the freezer from racing with regular CPU hotplug.
621 *
622 * This synchronization is implemented by mutually excluding regular CPU
623 * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
624 * Hibernate notifications.
625 */
626static int
627cpu_hotplug_pm_callback(struct notifier_block *nb,
628 unsigned long action, void *ptr)
629{
630 switch (action) {
631
632 case PM_SUSPEND_PREPARE:
633 case PM_HIBERNATION_PREPARE:
634 cpu_hotplug_disable();
635 break;
636
637 case PM_POST_SUSPEND:
638 case PM_POST_HIBERNATION:
639 cpu_hotplug_enable();
640 break;
641
642 default:
643 return NOTIFY_DONE;
644 }
645
646 return NOTIFY_OK;
647}
648
649
650static int __init cpu_hotplug_pm_sync_init(void)
651{
652 /*
653 * cpu_hotplug_pm_callback has higher priority than x86
654 * bsp_pm_callback which depends on cpu_hotplug_pm_callback
655 * to disable cpu hotplug to avoid cpu hotplug race.
656 */
657 pm_notifier(cpu_hotplug_pm_callback, 0);
658 return 0;
659}
660core_initcall(cpu_hotplug_pm_sync_init);
661
662#endif /* CONFIG_PM_SLEEP_SMP */
663
664/**
665 * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
666 * @cpu: cpu that just started
667 *
668 * This function calls the cpu_chain notifiers with CPU_STARTING.
669 * It must be called by the arch code on the new cpu, before the new cpu
670 * enables interrupts and before the "boot" cpu returns from __cpu_up().
671 */
672void notify_cpu_starting(unsigned int cpu)
673{
674 unsigned long val = CPU_STARTING;
675
676#ifdef CONFIG_PM_SLEEP_SMP
677 if (frozen_cpus != NULL && cpumask_test_cpu(cpu, frozen_cpus))
678 val = CPU_STARTING_FROZEN;
679#endif /* CONFIG_PM_SLEEP_SMP */
680 cpu_notify(val, (void *)(long)cpu);
681}
682
683#endif /* CONFIG_SMP */
684
685/*
686 * cpu_bit_bitmap[] is a special, "compressed" data structure that
687 * represents all NR_CPUS bits binary values of 1<<nr.
688 *
689 * It is used by cpumask_of() to get a constant address to a CPU
690 * mask value that has a single bit set only.
691 */
692
693/* cpu_bit_bitmap[0] is empty - so we can back into it */
694#define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x))
695#define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1)
696#define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2)
697#define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4)
698
699const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = {
700
701 MASK_DECLARE_8(0), MASK_DECLARE_8(8),
702 MASK_DECLARE_8(16), MASK_DECLARE_8(24),
703#if BITS_PER_LONG > 32
704 MASK_DECLARE_8(32), MASK_DECLARE_8(40),
705 MASK_DECLARE_8(48), MASK_DECLARE_8(56),
706#endif
707};
708EXPORT_SYMBOL_GPL(cpu_bit_bitmap);
709
710const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
711EXPORT_SYMBOL(cpu_all_bits);
712
713#ifdef CONFIG_INIT_ALL_POSSIBLE
714static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly
715 = CPU_BITS_ALL;
716#else
717static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly;
718#endif
719const struct cpumask *const cpu_possible_mask = to_cpumask(cpu_possible_bits);
720EXPORT_SYMBOL(cpu_possible_mask);
721
722static DECLARE_BITMAP(cpu_online_bits, CONFIG_NR_CPUS) __read_mostly;
723const struct cpumask *const cpu_online_mask = to_cpumask(cpu_online_bits);
724EXPORT_SYMBOL(cpu_online_mask);
725
726static DECLARE_BITMAP(cpu_present_bits, CONFIG_NR_CPUS) __read_mostly;
727const struct cpumask *const cpu_present_mask = to_cpumask(cpu_present_bits);
728EXPORT_SYMBOL(cpu_present_mask);
729
730static DECLARE_BITMAP(cpu_active_bits, CONFIG_NR_CPUS) __read_mostly;
731const struct cpumask *const cpu_active_mask = to_cpumask(cpu_active_bits);
732EXPORT_SYMBOL(cpu_active_mask);
733
734void set_cpu_possible(unsigned int cpu, bool possible)
735{
736 if (possible)
737 cpumask_set_cpu(cpu, to_cpumask(cpu_possible_bits));
738 else
739 cpumask_clear_cpu(cpu, to_cpumask(cpu_possible_bits));
740}
741
742void set_cpu_present(unsigned int cpu, bool present)
743{
744 if (present)
745 cpumask_set_cpu(cpu, to_cpumask(cpu_present_bits));
746 else
747 cpumask_clear_cpu(cpu, to_cpumask(cpu_present_bits));
748}
749
750void set_cpu_online(unsigned int cpu, bool online)
751{
752 if (online) {
753 cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits));
754 cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits));
755 } else {
756 cpumask_clear_cpu(cpu, to_cpumask(cpu_online_bits));
757 }
758}
759
760void set_cpu_active(unsigned int cpu, bool active)
761{
762 if (active)
763 cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits));
764 else
765 cpumask_clear_cpu(cpu, to_cpumask(cpu_active_bits));
766}
767
768void init_cpu_present(const struct cpumask *src)
769{
770 cpumask_copy(to_cpumask(cpu_present_bits), src);
771}
772
773void init_cpu_possible(const struct cpumask *src)
774{
775 cpumask_copy(to_cpumask(cpu_possible_bits), src);
776}
777
778void init_cpu_online(const struct cpumask *src)
779{
780 cpumask_copy(to_cpumask(cpu_online_bits), src);
781}