Line data Source code
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 */
29 : static 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 : */
38 : void cpu_maps_update_begin(void)
39 : {
40 : mutex_lock(&cpu_add_remove_lock);
41 : }
42 : EXPORT_SYMBOL(cpu_notifier_register_begin);
43 :
44 : void cpu_maps_update_done(void)
45 : {
46 : mutex_unlock(&cpu_add_remove_lock);
47 : }
48 : EXPORT_SYMBOL(cpu_notifier_register_done);
49 :
50 : static 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 : */
55 : static int cpu_hotplug_disabled;
56 :
57 : #ifdef CONFIG_HOTPLUG_CPU
58 :
59 : static 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 : /* And allows lockless put_online_cpus(). */
68 : atomic_t puts_pending;
69 :
70 : #ifdef CONFIG_DEBUG_LOCK_ALLOC
71 : struct lockdep_map dep_map;
72 : #endif
73 : } cpu_hotplug = {
74 : .active_writer = NULL,
75 : .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),
76 : .refcount = 0,
77 : #ifdef CONFIG_DEBUG_LOCK_ALLOC
78 : .dep_map = {.name = "cpu_hotplug.lock" },
79 : #endif
80 : };
81 :
82 : /* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */
83 : #define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map)
84 : #define cpuhp_lock_acquire_tryread() \
85 : lock_map_acquire_tryread(&cpu_hotplug.dep_map)
86 : #define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map)
87 : #define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)
88 :
89 : static void apply_puts_pending(int max)
90 : {
91 : int delta;
92 :
93 : if (atomic_read(&cpu_hotplug.puts_pending) >= max) {
94 : delta = atomic_xchg(&cpu_hotplug.puts_pending, 0);
95 : cpu_hotplug.refcount -= delta;
96 : }
97 : }
98 :
99 : void get_online_cpus(void)
100 : {
101 : might_sleep();
102 : if (cpu_hotplug.active_writer == current)
103 : return;
104 : cpuhp_lock_acquire_read();
105 : mutex_lock(&cpu_hotplug.lock);
106 : apply_puts_pending(65536);
107 : cpu_hotplug.refcount++;
108 : mutex_unlock(&cpu_hotplug.lock);
109 : }
110 : EXPORT_SYMBOL_GPL(get_online_cpus);
111 :
112 : bool try_get_online_cpus(void)
113 : {
114 : if (cpu_hotplug.active_writer == current)
115 : return true;
116 : if (!mutex_trylock(&cpu_hotplug.lock))
117 : return false;
118 : cpuhp_lock_acquire_tryread();
119 : apply_puts_pending(65536);
120 : cpu_hotplug.refcount++;
121 : mutex_unlock(&cpu_hotplug.lock);
122 : return true;
123 : }
124 : EXPORT_SYMBOL_GPL(try_get_online_cpus);
125 :
126 : void put_online_cpus(void)
127 : {
128 : if (cpu_hotplug.active_writer == current)
129 : return;
130 : if (!mutex_trylock(&cpu_hotplug.lock)) {
131 : atomic_inc(&cpu_hotplug.puts_pending);
132 : cpuhp_lock_release();
133 : return;
134 : }
135 :
136 : if (WARN_ON(!cpu_hotplug.refcount))
137 : cpu_hotplug.refcount++; /* try to fix things up */
138 :
139 : if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer))
140 : wake_up_process(cpu_hotplug.active_writer);
141 : mutex_unlock(&cpu_hotplug.lock);
142 : cpuhp_lock_release();
143 :
144 : }
145 : EXPORT_SYMBOL_GPL(put_online_cpus);
146 :
147 : /*
148 : * This ensures that the hotplug operation can begin only when the
149 : * refcount goes to zero.
150 : *
151 : * Note that during a cpu-hotplug operation, the new readers, if any,
152 : * will be blocked by the cpu_hotplug.lock
153 : *
154 : * Since cpu_hotplug_begin() is always called after invoking
155 : * cpu_maps_update_begin(), we can be sure that only one writer is active.
156 : *
157 : * Note that theoretically, there is a possibility of a livelock:
158 : * - Refcount goes to zero, last reader wakes up the sleeping
159 : * writer.
160 : * - Last reader unlocks the cpu_hotplug.lock.
161 : * - A new reader arrives at this moment, bumps up the refcount.
162 : * - The writer acquires the cpu_hotplug.lock finds the refcount
163 : * non zero and goes to sleep again.
164 : *
165 : * However, this is very difficult to achieve in practice since
166 : * get_online_cpus() not an api which is called all that often.
167 : *
168 : */
169 : void cpu_hotplug_begin(void)
170 : {
171 : cpu_hotplug.active_writer = current;
172 :
173 : cpuhp_lock_acquire();
174 : for (;;) {
175 : mutex_lock(&cpu_hotplug.lock);
176 : apply_puts_pending(1);
177 : if (likely(!cpu_hotplug.refcount))
178 : break;
179 : __set_current_state(TASK_UNINTERRUPTIBLE);
180 : mutex_unlock(&cpu_hotplug.lock);
181 : schedule();
182 : }
183 : }
184 :
185 : void cpu_hotplug_done(void)
186 : {
187 : cpu_hotplug.active_writer = NULL;
188 : mutex_unlock(&cpu_hotplug.lock);
189 : cpuhp_lock_release();
190 : }
191 :
192 : /*
193 : * Wait for currently running CPU hotplug operations to complete (if any) and
194 : * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
195 : * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the
196 : * hotplug path before performing hotplug operations. So acquiring that lock
197 : * guarantees mutual exclusion from any currently running hotplug operations.
198 : */
199 : void cpu_hotplug_disable(void)
200 : {
201 : cpu_maps_update_begin();
202 : cpu_hotplug_disabled = 1;
203 : cpu_maps_update_done();
204 : }
205 :
206 : void cpu_hotplug_enable(void)
207 : {
208 : cpu_maps_update_begin();
209 : cpu_hotplug_disabled = 0;
210 : cpu_maps_update_done();
211 : }
212 :
213 : #endif /* CONFIG_HOTPLUG_CPU */
214 :
215 : /* Need to know about CPUs going up/down? */
216 : int __ref register_cpu_notifier(struct notifier_block *nb)
217 : {
218 : int ret;
219 : cpu_maps_update_begin();
220 : ret = raw_notifier_chain_register(&cpu_chain, nb);
221 : cpu_maps_update_done();
222 : return ret;
223 : }
224 :
225 : int __ref __register_cpu_notifier(struct notifier_block *nb)
226 : {
227 : return raw_notifier_chain_register(&cpu_chain, nb);
228 : }
229 :
230 : static int __cpu_notify(unsigned long val, void *v, int nr_to_call,
231 : int *nr_calls)
232 : {
233 : int ret;
234 :
235 : ret = __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call,
236 : nr_calls);
237 :
238 : return notifier_to_errno(ret);
239 : }
240 :
241 : static int cpu_notify(unsigned long val, void *v)
242 : {
243 : return __cpu_notify(val, v, -1, NULL);
244 : }
245 :
246 : #ifdef CONFIG_HOTPLUG_CPU
247 :
248 : static void cpu_notify_nofail(unsigned long val, void *v)
249 : {
250 : BUG_ON(cpu_notify(val, v));
251 : }
252 : EXPORT_SYMBOL(register_cpu_notifier);
253 : EXPORT_SYMBOL(__register_cpu_notifier);
254 :
255 : void __ref unregister_cpu_notifier(struct notifier_block *nb)
256 : {
257 : cpu_maps_update_begin();
258 : raw_notifier_chain_unregister(&cpu_chain, nb);
259 : cpu_maps_update_done();
260 : }
261 : EXPORT_SYMBOL(unregister_cpu_notifier);
262 :
263 : void __ref __unregister_cpu_notifier(struct notifier_block *nb)
264 : {
265 : raw_notifier_chain_unregister(&cpu_chain, nb);
266 : }
267 : EXPORT_SYMBOL(__unregister_cpu_notifier);
268 :
269 : /**
270 : * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
271 : * @cpu: a CPU id
272 : *
273 : * This function walks all processes, finds a valid mm struct for each one and
274 : * then clears a corresponding bit in mm's cpumask. While this all sounds
275 : * trivial, there are various non-obvious corner cases, which this function
276 : * tries to solve in a safe manner.
277 : *
278 : * Also note that the function uses a somewhat relaxed locking scheme, so it may
279 : * be called only for an already offlined CPU.
280 : */
281 : void clear_tasks_mm_cpumask(int cpu)
282 : {
283 : struct task_struct *p;
284 :
285 : /*
286 : * This function is called after the cpu is taken down and marked
287 : * offline, so its not like new tasks will ever get this cpu set in
288 : * their mm mask. -- Peter Zijlstra
289 : * Thus, we may use rcu_read_lock() here, instead of grabbing
290 : * full-fledged tasklist_lock.
291 : */
292 : WARN_ON(cpu_online(cpu));
293 : rcu_read_lock();
294 : for_each_process(p) {
295 : struct task_struct *t;
296 :
297 : /*
298 : * Main thread might exit, but other threads may still have
299 : * a valid mm. Find one.
300 : */
301 : t = find_lock_task_mm(p);
302 : if (!t)
303 : continue;
304 : cpumask_clear_cpu(cpu, mm_cpumask(t->mm));
305 : task_unlock(t);
306 : }
307 : rcu_read_unlock();
308 : }
309 :
310 : static inline void check_for_tasks(int dead_cpu)
311 : {
312 : struct task_struct *g, *p;
313 :
314 : read_lock_irq(&tasklist_lock);
315 : do_each_thread(g, p) {
316 : if (!p->on_rq)
317 : continue;
318 : /*
319 : * We do the check with unlocked task_rq(p)->lock.
320 : * Order the reading to do not warn about a task,
321 : * which was running on this cpu in the past, and
322 : * it's just been woken on another cpu.
323 : */
324 : rmb();
325 : if (task_cpu(p) != dead_cpu)
326 : continue;
327 :
328 : pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n",
329 : p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags);
330 : } while_each_thread(g, p);
331 : read_unlock_irq(&tasklist_lock);
332 : }
333 :
334 : struct take_cpu_down_param {
335 : unsigned long mod;
336 : void *hcpu;
337 : };
338 :
339 : /* Take this CPU down. */
340 : static int __ref take_cpu_down(void *_param)
341 : {
342 : struct take_cpu_down_param *param = _param;
343 : int err;
344 :
345 : /* Ensure this CPU doesn't handle any more interrupts. */
346 : err = __cpu_disable();
347 : if (err < 0)
348 : return err;
349 :
350 : cpu_notify(CPU_DYING | param->mod, param->hcpu);
351 : /* Park the stopper thread */
352 : kthread_park(current);
353 : return 0;
354 : }
355 :
356 : /* Requires cpu_add_remove_lock to be held */
357 : static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
358 : {
359 : int err, nr_calls = 0;
360 : void *hcpu = (void *)(long)cpu;
361 : unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
362 : struct take_cpu_down_param tcd_param = {
363 : .mod = mod,
364 : .hcpu = hcpu,
365 : };
366 :
367 : if (num_online_cpus() == 1)
368 : return -EBUSY;
369 :
370 : if (!cpu_online(cpu))
371 : return -EINVAL;
372 :
373 : cpu_hotplug_begin();
374 :
375 : err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls);
376 : if (err) {
377 : nr_calls--;
378 : __cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL);
379 : pr_warn("%s: attempt to take down CPU %u failed\n",
380 : __func__, cpu);
381 : goto out_release;
382 : }
383 :
384 : /*
385 : * By now we've cleared cpu_active_mask, wait for all preempt-disabled
386 : * and RCU users of this state to go away such that all new such users
387 : * will observe it.
388 : *
389 : * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might
390 : * not imply sync_sched(), so explicitly call both.
391 : *
392 : * Do sync before park smpboot threads to take care the rcu boost case.
393 : */
394 : #ifdef CONFIG_PREEMPT
395 : synchronize_sched();
396 : #endif
397 : synchronize_rcu();
398 :
399 : smpboot_park_threads(cpu);
400 :
401 : /*
402 : * So now all preempt/rcu users must observe !cpu_active().
403 : */
404 :
405 : err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu));
406 : if (err) {
407 : /* CPU didn't die: tell everyone. Can't complain. */
408 : smpboot_unpark_threads(cpu);
409 : cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu);
410 : goto out_release;
411 : }
412 : BUG_ON(cpu_online(cpu));
413 :
414 : /*
415 : * The migration_call() CPU_DYING callback will have removed all
416 : * runnable tasks from the cpu, there's only the idle task left now
417 : * that the migration thread is done doing the stop_machine thing.
418 : *
419 : * Wait for the stop thread to go away.
420 : */
421 : while (!idle_cpu(cpu))
422 : cpu_relax();
423 :
424 : /* This actually kills the CPU. */
425 : __cpu_die(cpu);
426 :
427 : /* CPU is completely dead: tell everyone. Too late to complain. */
428 : cpu_notify_nofail(CPU_DEAD | mod, hcpu);
429 :
430 : check_for_tasks(cpu);
431 :
432 : out_release:
433 : cpu_hotplug_done();
434 : if (!err)
435 : cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu);
436 : return err;
437 : }
438 :
439 : int __ref cpu_down(unsigned int cpu)
440 : {
441 : int err;
442 :
443 : cpu_maps_update_begin();
444 :
445 : if (cpu_hotplug_disabled) {
446 : err = -EBUSY;
447 : goto out;
448 : }
449 :
450 : err = _cpu_down(cpu, 0);
451 :
452 : out:
453 : cpu_maps_update_done();
454 : return err;
455 : }
456 : EXPORT_SYMBOL(cpu_down);
457 : #endif /*CONFIG_HOTPLUG_CPU*/
458 :
459 : /* Requires cpu_add_remove_lock to be held */
460 : static int _cpu_up(unsigned int cpu, int tasks_frozen)
461 : {
462 : int ret, nr_calls = 0;
463 : void *hcpu = (void *)(long)cpu;
464 : unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
465 : struct task_struct *idle;
466 :
467 : cpu_hotplug_begin();
468 :
469 : if (cpu_online(cpu) || !cpu_present(cpu)) {
470 : ret = -EINVAL;
471 : goto out;
472 : }
473 :
474 : idle = idle_thread_get(cpu);
475 : if (IS_ERR(idle)) {
476 : ret = PTR_ERR(idle);
477 : goto out;
478 : }
479 :
480 : ret = smpboot_create_threads(cpu);
481 : if (ret)
482 : goto out;
483 :
484 : ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls);
485 : if (ret) {
486 : nr_calls--;
487 : pr_warn("%s: attempt to bring up CPU %u failed\n",
488 : __func__, cpu);
489 : goto out_notify;
490 : }
491 :
492 : /* Arch-specific enabling code. */
493 : ret = __cpu_up(cpu, idle);
494 : if (ret != 0)
495 : goto out_notify;
496 : BUG_ON(!cpu_online(cpu));
497 :
498 : /* Wake the per cpu threads */
499 : smpboot_unpark_threads(cpu);
500 :
501 : /* Now call notifier in preparation. */
502 : cpu_notify(CPU_ONLINE | mod, hcpu);
503 :
504 : out_notify:
505 : if (ret != 0)
506 : __cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);
507 : out:
508 : cpu_hotplug_done();
509 :
510 : return ret;
511 : }
512 :
513 : int cpu_up(unsigned int cpu)
514 : {
515 : int err = 0;
516 :
517 : if (!cpu_possible(cpu)) {
518 : pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n",
519 : cpu);
520 : #if defined(CONFIG_IA64)
521 : pr_err("please check additional_cpus= boot parameter\n");
522 : #endif
523 : return -EINVAL;
524 : }
525 :
526 : err = try_online_node(cpu_to_node(cpu));
527 : if (err)
528 : return err;
529 :
530 : cpu_maps_update_begin();
531 :
532 : if (cpu_hotplug_disabled) {
533 : err = -EBUSY;
534 : goto out;
535 : }
536 :
537 : err = _cpu_up(cpu, 0);
538 :
539 : out:
540 : cpu_maps_update_done();
541 : return err;
542 : }
543 : EXPORT_SYMBOL_GPL(cpu_up);
544 :
545 : #ifdef CONFIG_PM_SLEEP_SMP
546 : static cpumask_var_t frozen_cpus;
547 :
548 : int disable_nonboot_cpus(void)
549 : {
550 : int cpu, first_cpu, error = 0;
551 :
552 : cpu_maps_update_begin();
553 : first_cpu = cpumask_first(cpu_online_mask);
554 : /*
555 : * We take down all of the non-boot CPUs in one shot to avoid races
556 : * with the userspace trying to use the CPU hotplug at the same time
557 : */
558 : cpumask_clear(frozen_cpus);
559 :
560 : pr_info("Disabling non-boot CPUs ...\n");
561 : for_each_online_cpu(cpu) {
562 : if (cpu == first_cpu)
563 : continue;
564 : trace_suspend_resume(TPS("CPU_OFF"), cpu, true);
565 : error = _cpu_down(cpu, 1);
566 : trace_suspend_resume(TPS("CPU_OFF"), cpu, false);
567 : if (!error)
568 : cpumask_set_cpu(cpu, frozen_cpus);
569 : else {
570 : pr_err("Error taking CPU%d down: %d\n", cpu, error);
571 : break;
572 : }
573 : }
574 :
575 : if (!error) {
576 : BUG_ON(num_online_cpus() > 1);
577 : /* Make sure the CPUs won't be enabled by someone else */
578 : cpu_hotplug_disabled = 1;
579 : } else {
580 : pr_err("Non-boot CPUs are not disabled\n");
581 : }
582 : cpu_maps_update_done();
583 : return error;
584 : }
585 :
586 : void __weak arch_enable_nonboot_cpus_begin(void)
587 : {
588 : }
589 :
590 : void __weak arch_enable_nonboot_cpus_end(void)
591 : {
592 : }
593 :
594 : void __ref enable_nonboot_cpus(void)
595 : {
596 : int cpu, error;
597 :
598 : /* Allow everyone to use the CPU hotplug again */
599 : cpu_maps_update_begin();
600 : cpu_hotplug_disabled = 0;
601 : if (cpumask_empty(frozen_cpus))
602 : goto out;
603 :
604 : pr_info("Enabling non-boot CPUs ...\n");
605 :
606 : arch_enable_nonboot_cpus_begin();
607 :
608 : for_each_cpu(cpu, frozen_cpus) {
609 : trace_suspend_resume(TPS("CPU_ON"), cpu, true);
610 : error = _cpu_up(cpu, 1);
611 : trace_suspend_resume(TPS("CPU_ON"), cpu, false);
612 : if (!error) {
613 : pr_info("CPU%d is up\n", cpu);
614 : continue;
615 : }
616 : pr_warn("Error taking CPU%d up: %d\n", cpu, error);
617 : }
618 :
619 : arch_enable_nonboot_cpus_end();
620 :
621 : cpumask_clear(frozen_cpus);
622 : out:
623 : cpu_maps_update_done();
624 : }
625 :
626 : static int __init alloc_frozen_cpus(void)
627 : {
628 : if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO))
629 : return -ENOMEM;
630 : return 0;
631 : }
632 : core_initcall(alloc_frozen_cpus);
633 :
634 : /*
635 : * When callbacks for CPU hotplug notifications are being executed, we must
636 : * ensure that the state of the system with respect to the tasks being frozen
637 : * or not, as reported by the notification, remains unchanged *throughout the
638 : * duration* of the execution of the callbacks.
639 : * Hence we need to prevent the freezer from racing with regular CPU hotplug.
640 : *
641 : * This synchronization is implemented by mutually excluding regular CPU
642 : * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
643 : * Hibernate notifications.
644 : */
645 : static int
646 : cpu_hotplug_pm_callback(struct notifier_block *nb,
647 : unsigned long action, void *ptr)
648 : {
649 : switch (action) {
650 :
651 : case PM_SUSPEND_PREPARE:
652 : case PM_HIBERNATION_PREPARE:
653 : cpu_hotplug_disable();
654 : break;
655 :
656 : case PM_POST_SUSPEND:
657 : case PM_POST_HIBERNATION:
658 : cpu_hotplug_enable();
659 : break;
660 :
661 : default:
662 : return NOTIFY_DONE;
663 : }
664 :
665 : return NOTIFY_OK;
666 : }
667 :
668 :
669 : static int __init cpu_hotplug_pm_sync_init(void)
670 : {
671 : /*
672 : * cpu_hotplug_pm_callback has higher priority than x86
673 : * bsp_pm_callback which depends on cpu_hotplug_pm_callback
674 : * to disable cpu hotplug to avoid cpu hotplug race.
675 : */
676 : pm_notifier(cpu_hotplug_pm_callback, 0);
677 : return 0;
678 : }
679 : core_initcall(cpu_hotplug_pm_sync_init);
680 :
681 : #endif /* CONFIG_PM_SLEEP_SMP */
682 :
683 : /**
684 : * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
685 : * @cpu: cpu that just started
686 : *
687 : * This function calls the cpu_chain notifiers with CPU_STARTING.
688 : * It must be called by the arch code on the new cpu, before the new cpu
689 : * enables interrupts and before the "boot" cpu returns from __cpu_up().
690 : */
691 : void notify_cpu_starting(unsigned int cpu)
692 : {
693 : unsigned long val = CPU_STARTING;
694 :
695 : #ifdef CONFIG_PM_SLEEP_SMP
696 : if (frozen_cpus != NULL && cpumask_test_cpu(cpu, frozen_cpus))
697 : val = CPU_STARTING_FROZEN;
698 : #endif /* CONFIG_PM_SLEEP_SMP */
699 : cpu_notify(val, (void *)(long)cpu);
700 : }
701 :
702 : #endif /* CONFIG_SMP */
703 :
704 : /*
705 : * cpu_bit_bitmap[] is a special, "compressed" data structure that
706 : * represents all NR_CPUS bits binary values of 1<<nr.
707 : *
708 : * It is used by cpumask_of() to get a constant address to a CPU
709 : * mask value that has a single bit set only.
710 : */
711 :
712 : /* cpu_bit_bitmap[0] is empty - so we can back into it */
713 : #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x))
714 : #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1)
715 : #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2)
716 : #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4)
717 :
718 : const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = {
719 :
720 : MASK_DECLARE_8(0), MASK_DECLARE_8(8),
721 : MASK_DECLARE_8(16), MASK_DECLARE_8(24),
722 : #if BITS_PER_LONG > 32
723 : MASK_DECLARE_8(32), MASK_DECLARE_8(40),
724 : MASK_DECLARE_8(48), MASK_DECLARE_8(56),
725 : #endif
726 : };
727 : EXPORT_SYMBOL_GPL(cpu_bit_bitmap);
728 :
729 : const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
730 : EXPORT_SYMBOL(cpu_all_bits);
731 :
732 : #ifdef CONFIG_INIT_ALL_POSSIBLE
733 : static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly
734 : = CPU_BITS_ALL;
735 : #else
736 : static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly;
737 : #endif
738 : const struct cpumask *const cpu_possible_mask = to_cpumask(cpu_possible_bits);
739 : EXPORT_SYMBOL(cpu_possible_mask);
740 :
741 : static DECLARE_BITMAP(cpu_online_bits, CONFIG_NR_CPUS) __read_mostly;
742 : const struct cpumask *const cpu_online_mask = to_cpumask(cpu_online_bits);
743 : EXPORT_SYMBOL(cpu_online_mask);
744 :
745 : static DECLARE_BITMAP(cpu_present_bits, CONFIG_NR_CPUS) __read_mostly;
746 : const struct cpumask *const cpu_present_mask = to_cpumask(cpu_present_bits);
747 : EXPORT_SYMBOL(cpu_present_mask);
748 :
749 : static DECLARE_BITMAP(cpu_active_bits, CONFIG_NR_CPUS) __read_mostly;
750 : const struct cpumask *const cpu_active_mask = to_cpumask(cpu_active_bits);
751 : EXPORT_SYMBOL(cpu_active_mask);
752 :
753 1 : void set_cpu_possible(unsigned int cpu, bool possible)
754 : {
755 1 : if (possible)
756 : cpumask_set_cpu(cpu, to_cpumask(cpu_possible_bits));
757 : else
758 0 : cpumask_clear_cpu(cpu, to_cpumask(cpu_possible_bits));
759 1 : }
760 :
761 1 : void set_cpu_present(unsigned int cpu, bool present)
762 : {
763 1 : if (present)
764 : cpumask_set_cpu(cpu, to_cpumask(cpu_present_bits));
765 : else
766 0 : cpumask_clear_cpu(cpu, to_cpumask(cpu_present_bits));
767 1 : }
768 :
769 1 : void set_cpu_online(unsigned int cpu, bool online)
770 : {
771 1 : if (online) {
772 : cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits));
773 : cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits));
774 : } else {
775 0 : cpumask_clear_cpu(cpu, to_cpumask(cpu_online_bits));
776 : }
777 1 : }
778 :
779 1 : void set_cpu_active(unsigned int cpu, bool active)
780 : {
781 1 : if (active)
782 : cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits));
783 : else
784 0 : cpumask_clear_cpu(cpu, to_cpumask(cpu_active_bits));
785 1 : }
786 :
787 0 : void init_cpu_present(const struct cpumask *src)
788 : {
789 : cpumask_copy(to_cpumask(cpu_present_bits), src);
790 0 : }
791 :
792 0 : void init_cpu_possible(const struct cpumask *src)
793 : {
794 : cpumask_copy(to_cpumask(cpu_possible_bits), src);
795 0 : }
796 :
797 0 : void init_cpu_online(const struct cpumask *src)
798 : {
799 : cpumask_copy(to_cpumask(cpu_online_bits), src);
800 0 : }
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