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[mirror_ubuntu-bionic-kernel.git] / kernel / cpu.c
CommitLineData
1da177e4
LT
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>
cb79295e
AV
13#include <linux/oom.h>
14#include <linux/rcupdate.h>
9984de1a 15#include <linux/export.h>
e4cc2f87 16#include <linux/bug.h>
1da177e4
LT
17#include <linux/kthread.h>
18#include <linux/stop_machine.h>
81615b62 19#include <linux/mutex.h>
5a0e3ad6 20#include <linux/gfp.h>
79cfbdfa 21#include <linux/suspend.h>
a19423b9 22#include <linux/lockdep.h>
bb3632c6 23#include <trace/events/power.h>
1da177e4 24
38498a67
TG
25#include "smpboot.h"
26
98a79d6a 27#ifdef CONFIG_SMP
b3199c02 28/* Serializes the updates to cpu_online_mask, cpu_present_mask */
aa953877 29static DEFINE_MUTEX(cpu_add_remove_lock);
1da177e4 30
79a6cdeb 31/*
93ae4f97
SB
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().
79a6cdeb
LJ
37 */
38void cpu_maps_update_begin(void)
39{
40 mutex_lock(&cpu_add_remove_lock);
41}
93ae4f97 42EXPORT_SYMBOL(cpu_notifier_register_begin);
79a6cdeb
LJ
43
44void cpu_maps_update_done(void)
45{
46 mutex_unlock(&cpu_add_remove_lock);
47}
93ae4f97 48EXPORT_SYMBOL(cpu_notifier_register_done);
79a6cdeb 49
5c113fbe 50static RAW_NOTIFIER_HEAD(cpu_chain);
1da177e4 51
e3920fb4
RW
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
79a6cdeb
LJ
57#ifdef CONFIG_HOTPLUG_CPU
58
d221938c
GS
59static struct {
60 struct task_struct *active_writer;
87af9e7f
DH
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;
d221938c
GS
65 /*
66 * Also blocks the new readers during
67 * an ongoing cpu hotplug operation.
68 */
87af9e7f 69 atomic_t refcount;
a19423b9
GS
70
71#ifdef CONFIG_DEBUG_LOCK_ALLOC
72 struct lockdep_map dep_map;
73#endif
31950eb6
LT
74} cpu_hotplug = {
75 .active_writer = NULL,
87af9e7f 76 .wq = __WAIT_QUEUE_HEAD_INITIALIZER(cpu_hotplug.wq),
31950eb6 77 .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),
a19423b9
GS
78#ifdef CONFIG_DEBUG_LOCK_ALLOC
79 .dep_map = {.name = "cpu_hotplug.lock" },
80#endif
31950eb6 81};
d221938c 82
a19423b9
GS
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)
dd56af42
PM
85#define cpuhp_lock_acquire_tryread() \
86 lock_map_acquire_tryread(&cpu_hotplug.dep_map)
a19423b9
GS
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
62db99f4 90
86ef5c9a 91void get_online_cpus(void)
a9d9baa1 92{
d221938c
GS
93 might_sleep();
94 if (cpu_hotplug.active_writer == current)
aa953877 95 return;
a19423b9 96 cpuhp_lock_acquire_read();
d221938c 97 mutex_lock(&cpu_hotplug.lock);
87af9e7f 98 atomic_inc(&cpu_hotplug.refcount);
d221938c 99 mutex_unlock(&cpu_hotplug.lock);
a9d9baa1 100}
86ef5c9a 101EXPORT_SYMBOL_GPL(get_online_cpus);
90d45d17 102
dd56af42
PM
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();
87af9e7f 110 atomic_inc(&cpu_hotplug.refcount);
dd56af42
PM
111 mutex_unlock(&cpu_hotplug.lock);
112 return true;
113}
114EXPORT_SYMBOL_GPL(try_get_online_cpus);
115
86ef5c9a 116void put_online_cpus(void)
a9d9baa1 117{
87af9e7f
DH
118 int refcount;
119
d221938c 120 if (cpu_hotplug.active_writer == current)
aa953877 121 return;
075663d1 122
87af9e7f
DH
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);
075663d1 129
a19423b9 130 cpuhp_lock_release();
d221938c 131
a9d9baa1 132}
86ef5c9a 133EXPORT_SYMBOL_GPL(put_online_cpus);
a9d9baa1 134
d221938c
GS
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 *
d2ba7e2a
ON
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.
d221938c
GS
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
86ef5c9a 154 * get_online_cpus() not an api which is called all that often.
d221938c
GS
155 *
156 */
b9d10be7 157void cpu_hotplug_begin(void)
d221938c 158{
87af9e7f 159 DEFINE_WAIT(wait);
d2ba7e2a 160
87af9e7f 161 cpu_hotplug.active_writer = current;
a19423b9 162 cpuhp_lock_acquire();
87af9e7f 163
d2ba7e2a
ON
164 for (;;) {
165 mutex_lock(&cpu_hotplug.lock);
87af9e7f
DH
166 prepare_to_wait(&cpu_hotplug.wq, &wait, TASK_UNINTERRUPTIBLE);
167 if (likely(!atomic_read(&cpu_hotplug.refcount)))
168 break;
d221938c
GS
169 mutex_unlock(&cpu_hotplug.lock);
170 schedule();
d221938c 171 }
87af9e7f 172 finish_wait(&cpu_hotplug.wq, &wait);
d221938c
GS
173}
174
b9d10be7 175void cpu_hotplug_done(void)
d221938c
GS
176{
177 cpu_hotplug.active_writer = NULL;
178 mutex_unlock(&cpu_hotplug.lock);
a19423b9 179 cpuhp_lock_release();
d221938c 180}
79a6cdeb 181
16e53dbf
SB
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
b9d10be7 203#endif /* CONFIG_HOTPLUG_CPU */
79a6cdeb 204
1da177e4 205/* Need to know about CPUs going up/down? */
f7b16c10 206int __ref register_cpu_notifier(struct notifier_block *nb)
1da177e4 207{
bd5349cf 208 int ret;
d221938c 209 cpu_maps_update_begin();
bd5349cf 210 ret = raw_notifier_chain_register(&cpu_chain, nb);
d221938c 211 cpu_maps_update_done();
bd5349cf 212 return ret;
1da177e4 213}
65edc68c 214
93ae4f97
SB
215int __ref __register_cpu_notifier(struct notifier_block *nb)
216{
217 return raw_notifier_chain_register(&cpu_chain, nb);
218}
219
e9fb7631
AM
220static int __cpu_notify(unsigned long val, void *v, int nr_to_call,
221 int *nr_calls)
222{
e6bde73b
AM
223 int ret;
224
225 ret = __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call,
e9fb7631 226 nr_calls);
e6bde73b
AM
227
228 return notifier_to_errno(ret);
e9fb7631
AM
229}
230
231static int cpu_notify(unsigned long val, void *v)
232{
233 return __cpu_notify(val, v, -1, NULL);
234}
235
00b9b0af
LT
236#ifdef CONFIG_HOTPLUG_CPU
237
e9fb7631
AM
238static void cpu_notify_nofail(unsigned long val, void *v)
239{
00b9b0af 240 BUG_ON(cpu_notify(val, v));
e9fb7631 241}
1da177e4 242EXPORT_SYMBOL(register_cpu_notifier);
93ae4f97 243EXPORT_SYMBOL(__register_cpu_notifier);
1da177e4 244
9647155f 245void __ref unregister_cpu_notifier(struct notifier_block *nb)
1da177e4 246{
d221938c 247 cpu_maps_update_begin();
bd5349cf 248 raw_notifier_chain_unregister(&cpu_chain, nb);
d221938c 249 cpu_maps_update_done();
1da177e4
LT
250}
251EXPORT_SYMBOL(unregister_cpu_notifier);
252
93ae4f97
SB
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
e4cc2f87
AV
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 */
cb79295e
AV
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 */
e4cc2f87 282 WARN_ON(cpu_online(cpu));
cb79295e
AV
283 rcu_read_lock();
284 for_each_process(p) {
285 struct task_struct *t;
286
e4cc2f87
AV
287 /*
288 * Main thread might exit, but other threads may still have
289 * a valid mm. Find one.
290 */
cb79295e
AV
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
b728ca06 300static inline void check_for_tasks(int dead_cpu)
1da177e4 301{
b728ca06 302 struct task_struct *g, *p;
1da177e4 303
b728ca06
KT
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);
1da177e4
LT
322}
323
db912f96
AK
324struct take_cpu_down_param {
325 unsigned long mod;
326 void *hcpu;
327};
328
1da177e4 329/* Take this CPU down. */
514a20a5 330static int __ref take_cpu_down(void *_param)
1da177e4 331{
db912f96 332 struct take_cpu_down_param *param = _param;
1da177e4
LT
333 int err;
334
1da177e4
LT
335 /* Ensure this CPU doesn't handle any more interrupts. */
336 err = __cpu_disable();
337 if (err < 0)
f3705136 338 return err;
1da177e4 339
e9fb7631 340 cpu_notify(CPU_DYING | param->mod, param->hcpu);
14e568e7
TG
341 /* Park the stopper thread */
342 kthread_park(current);
f3705136 343 return 0;
1da177e4
LT
344}
345
e3920fb4 346/* Requires cpu_add_remove_lock to be held */
514a20a5 347static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
1da177e4 348{
e7407dcc 349 int err, nr_calls = 0;
e7407dcc 350 void *hcpu = (void *)(long)cpu;
8bb78442 351 unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
db912f96
AK
352 struct take_cpu_down_param tcd_param = {
353 .mod = mod,
354 .hcpu = hcpu,
355 };
1da177e4 356
e3920fb4
RW
357 if (num_online_cpus() == 1)
358 return -EBUSY;
1da177e4 359
e3920fb4
RW
360 if (!cpu_online(cpu))
361 return -EINVAL;
1da177e4 362
d221938c 363 cpu_hotplug_begin();
4d51985e 364
e9fb7631 365 err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls);
e6bde73b 366 if (err) {
a0d8cdb6 367 nr_calls--;
e9fb7631 368 __cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL);
84117da5
FF
369 pr_warn("%s: attempt to take down CPU %u failed\n",
370 __func__, cpu);
baaca49f 371 goto out_release;
1da177e4
LT
372 }
373
6acce3ef
PZ
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.
106dd5af
M
381 *
382 * Do sync before park smpboot threads to take care the rcu boost case.
6acce3ef
PZ
383 */
384#ifdef CONFIG_PREEMPT
385 synchronize_sched();
386#endif
387 synchronize_rcu();
388
106dd5af
M
389 smpboot_park_threads(cpu);
390
6acce3ef
PZ
391 /*
392 * So now all preempt/rcu users must observe !cpu_active().
393 */
394
e0b582ec 395 err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu));
04321587 396 if (err) {
1da177e4 397 /* CPU didn't die: tell everyone. Can't complain. */
f97f8f06 398 smpboot_unpark_threads(cpu);
e9fb7631 399 cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu);
6a1bdc1b 400 goto out_release;
8fa1d7d3 401 }
04321587 402 BUG_ON(cpu_online(cpu));
1da177e4 403
48c5ccae
PZ
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.
51a96c77
PZ
408 *
409 * Wait for the stop thread to go away.
48c5ccae 410 */
51a96c77
PZ
411 while (!idle_cpu(cpu))
412 cpu_relax();
1da177e4
LT
413
414 /* This actually kills the CPU. */
415 __cpu_die(cpu);
416
1da177e4 417 /* CPU is completely dead: tell everyone. Too late to complain. */
e9fb7631 418 cpu_notify_nofail(CPU_DEAD | mod, hcpu);
1da177e4
LT
419
420 check_for_tasks(cpu);
421
baaca49f 422out_release:
d221938c 423 cpu_hotplug_done();
e9fb7631
AM
424 if (!err)
425 cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu);
e3920fb4
RW
426 return err;
427}
428
514a20a5 429int __ref cpu_down(unsigned int cpu)
e3920fb4 430{
9ea09af3 431 int err;
e3920fb4 432
d221938c 433 cpu_maps_update_begin();
e761b772
MK
434
435 if (cpu_hotplug_disabled) {
e3920fb4 436 err = -EBUSY;
e761b772
MK
437 goto out;
438 }
439
e761b772 440 err = _cpu_down(cpu, 0);
e3920fb4 441
e761b772 442out:
d221938c 443 cpu_maps_update_done();
1da177e4
LT
444 return err;
445}
b62b8ef9 446EXPORT_SYMBOL(cpu_down);
1da177e4
LT
447#endif /*CONFIG_HOTPLUG_CPU*/
448
e3920fb4 449/* Requires cpu_add_remove_lock to be held */
0db0628d 450static int _cpu_up(unsigned int cpu, int tasks_frozen)
1da177e4 451{
baaca49f 452 int ret, nr_calls = 0;
1da177e4 453 void *hcpu = (void *)(long)cpu;
8bb78442 454 unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
3bb5d2ee 455 struct task_struct *idle;
1da177e4 456
d221938c 457 cpu_hotplug_begin();
38498a67 458
5e5041f3
YI
459 if (cpu_online(cpu) || !cpu_present(cpu)) {
460 ret = -EINVAL;
461 goto out;
462 }
463
3bb5d2ee
SS
464 idle = idle_thread_get(cpu);
465 if (IS_ERR(idle)) {
466 ret = PTR_ERR(idle);
38498a67 467 goto out;
3bb5d2ee 468 }
38498a67 469
f97f8f06
TG
470 ret = smpboot_create_threads(cpu);
471 if (ret)
472 goto out;
473
e9fb7631 474 ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls);
e6bde73b 475 if (ret) {
a0d8cdb6 476 nr_calls--;
84117da5
FF
477 pr_warn("%s: attempt to bring up CPU %u failed\n",
478 __func__, cpu);
1da177e4
LT
479 goto out_notify;
480 }
481
482 /* Arch-specific enabling code. */
3bb5d2ee 483 ret = __cpu_up(cpu, idle);
1da177e4
LT
484 if (ret != 0)
485 goto out_notify;
6978c705 486 BUG_ON(!cpu_online(cpu));
1da177e4 487
f97f8f06
TG
488 /* Wake the per cpu threads */
489 smpboot_unpark_threads(cpu);
490
1da177e4 491 /* Now call notifier in preparation. */
e9fb7631 492 cpu_notify(CPU_ONLINE | mod, hcpu);
1da177e4
LT
493
494out_notify:
495 if (ret != 0)
e9fb7631 496 __cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);
38498a67 497out:
d221938c 498 cpu_hotplug_done();
e3920fb4
RW
499
500 return ret;
501}
502
0db0628d 503int cpu_up(unsigned int cpu)
e3920fb4
RW
504{
505 int err = 0;
cf23422b 506
e0b582ec 507 if (!cpu_possible(cpu)) {
84117da5
FF
508 pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n",
509 cpu);
87d5e023 510#if defined(CONFIG_IA64)
84117da5 511 pr_err("please check additional_cpus= boot parameter\n");
73e753a5
KH
512#endif
513 return -EINVAL;
514 }
e3920fb4 515
01b0f197
TK
516 err = try_online_node(cpu_to_node(cpu));
517 if (err)
518 return err;
cf23422b 519
d221938c 520 cpu_maps_update_begin();
e761b772
MK
521
522 if (cpu_hotplug_disabled) {
e3920fb4 523 err = -EBUSY;
e761b772
MK
524 goto out;
525 }
526
527 err = _cpu_up(cpu, 0);
528
e761b772 529out:
d221938c 530 cpu_maps_update_done();
e3920fb4
RW
531 return err;
532}
a513f6ba 533EXPORT_SYMBOL_GPL(cpu_up);
e3920fb4 534
f3de4be9 535#ifdef CONFIG_PM_SLEEP_SMP
e0b582ec 536static cpumask_var_t frozen_cpus;
e3920fb4
RW
537
538int disable_nonboot_cpus(void)
539{
e9a5f426 540 int cpu, first_cpu, error = 0;
e3920fb4 541
d221938c 542 cpu_maps_update_begin();
e0b582ec 543 first_cpu = cpumask_first(cpu_online_mask);
9ee349ad
XF
544 /*
545 * We take down all of the non-boot CPUs in one shot to avoid races
e3920fb4
RW
546 * with the userspace trying to use the CPU hotplug at the same time
547 */
e0b582ec 548 cpumask_clear(frozen_cpus);
6ad4c188 549
84117da5 550 pr_info("Disabling non-boot CPUs ...\n");
e3920fb4
RW
551 for_each_online_cpu(cpu) {
552 if (cpu == first_cpu)
553 continue;
bb3632c6 554 trace_suspend_resume(TPS("CPU_OFF"), cpu, true);
8bb78442 555 error = _cpu_down(cpu, 1);
bb3632c6 556 trace_suspend_resume(TPS("CPU_OFF"), cpu, false);
feae3203 557 if (!error)
e0b582ec 558 cpumask_set_cpu(cpu, frozen_cpus);
feae3203 559 else {
84117da5 560 pr_err("Error taking CPU%d down: %d\n", cpu, error);
e3920fb4
RW
561 break;
562 }
563 }
86886e55 564
e3920fb4
RW
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 {
84117da5 570 pr_err("Non-boot CPUs are not disabled\n");
e3920fb4 571 }
d221938c 572 cpu_maps_update_done();
e3920fb4
RW
573 return error;
574}
575
d0af9eed
SS
576void __weak arch_enable_nonboot_cpus_begin(void)
577{
578}
579
580void __weak arch_enable_nonboot_cpus_end(void)
581{
582}
583
fa7303e2 584void __ref enable_nonboot_cpus(void)
e3920fb4
RW
585{
586 int cpu, error;
587
588 /* Allow everyone to use the CPU hotplug again */
d221938c 589 cpu_maps_update_begin();
e3920fb4 590 cpu_hotplug_disabled = 0;
e0b582ec 591 if (cpumask_empty(frozen_cpus))
1d64b9cb 592 goto out;
e3920fb4 593
84117da5 594 pr_info("Enabling non-boot CPUs ...\n");
d0af9eed
SS
595
596 arch_enable_nonboot_cpus_begin();
597
e0b582ec 598 for_each_cpu(cpu, frozen_cpus) {
bb3632c6 599 trace_suspend_resume(TPS("CPU_ON"), cpu, true);
8bb78442 600 error = _cpu_up(cpu, 1);
bb3632c6 601 trace_suspend_resume(TPS("CPU_ON"), cpu, false);
e3920fb4 602 if (!error) {
84117da5 603 pr_info("CPU%d is up\n", cpu);
e3920fb4
RW
604 continue;
605 }
84117da5 606 pr_warn("Error taking CPU%d up: %d\n", cpu, error);
e3920fb4 607 }
d0af9eed
SS
608
609 arch_enable_nonboot_cpus_end();
610
e0b582ec 611 cpumask_clear(frozen_cpus);
1d64b9cb 612out:
d221938c 613 cpu_maps_update_done();
1da177e4 614}
e0b582ec 615
d7268a31 616static int __init alloc_frozen_cpus(void)
e0b582ec
RR
617{
618 if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO))
619 return -ENOMEM;
620 return 0;
621}
622core_initcall(alloc_frozen_cpus);
79cfbdfa 623
79cfbdfa
SB
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:
16e53dbf 643 cpu_hotplug_disable();
79cfbdfa
SB
644 break;
645
646 case PM_POST_SUSPEND:
647 case PM_POST_HIBERNATION:
16e53dbf 648 cpu_hotplug_enable();
79cfbdfa
SB
649 break;
650
651 default:
652 return NOTIFY_DONE;
653 }
654
655 return NOTIFY_OK;
656}
657
658
d7268a31 659static int __init cpu_hotplug_pm_sync_init(void)
79cfbdfa 660{
6e32d479
FY
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 */
79cfbdfa
SB
666 pm_notifier(cpu_hotplug_pm_callback, 0);
667 return 0;
668}
669core_initcall(cpu_hotplug_pm_sync_init);
670
f3de4be9 671#endif /* CONFIG_PM_SLEEP_SMP */
68f4f1ec 672
e545a614
MS
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 */
0db0628d 681void notify_cpu_starting(unsigned int cpu)
e545a614
MS
682{
683 unsigned long val = CPU_STARTING;
684
685#ifdef CONFIG_PM_SLEEP_SMP
e0b582ec 686 if (frozen_cpus != NULL && cpumask_test_cpu(cpu, frozen_cpus))
e545a614
MS
687 val = CPU_STARTING_FROZEN;
688#endif /* CONFIG_PM_SLEEP_SMP */
e9fb7631 689 cpu_notify(val, (void *)(long)cpu);
e545a614
MS
690}
691
68f4f1ec 692#endif /* CONFIG_SMP */
b8d317d1 693
e56b3bc7
LT
694/*
695 * cpu_bit_bitmap[] is a special, "compressed" data structure that
696 * represents all NR_CPUS bits binary values of 1<<nr.
697 *
e0b582ec 698 * It is used by cpumask_of() to get a constant address to a CPU
e56b3bc7
LT
699 * mask value that has a single bit set only.
700 */
b8d317d1 701
e56b3bc7 702/* cpu_bit_bitmap[0] is empty - so we can back into it */
4d51985e 703#define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x))
e56b3bc7
LT
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)
b8d317d1 707
e56b3bc7
LT
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),
b8d317d1
MT
715#endif
716};
e56b3bc7 717EXPORT_SYMBOL_GPL(cpu_bit_bitmap);
2d3854a3
RR
718
719const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
720EXPORT_SYMBOL(cpu_all_bits);
b3199c02
RR
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);
3fa41520
RR
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{
6acbfb96 761 if (online) {
3fa41520 762 cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits));
6acbfb96
LJ
763 cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits));
764 } else {
3fa41520 765 cpumask_clear_cpu(cpu, to_cpumask(cpu_online_bits));
6acbfb96 766 }
3fa41520
RR
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}