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