2 * (C) 2001, 2002, 2003, 2004 Rusty Russell
4 * This code is licenced under the GPL.
6 #include <linux/proc_fs.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 <linux/tick.h>
24 #include <linux/irq.h>
26 #include <trace/events/power.h>
27 #define CREATE_TRACE_POINTS
28 #include <trace/events/cpuhp.h>
33 * cpuhp_cpu_state - Per cpu hotplug state storage
34 * @state: The current cpu state
35 * @target: The target state
37 struct cpuhp_cpu_state {
38 enum cpuhp_state state;
39 enum cpuhp_state target;
42 static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state);
45 * cpuhp_step - Hotplug state machine step
46 * @name: Name of the step
47 * @startup: Startup function of the step
48 * @teardown: Teardown function of the step
49 * @skip_onerr: Do not invoke the functions on error rollback
50 * Will go away once the notifiers are gone
54 int (*startup)(unsigned int cpu);
55 int (*teardown)(unsigned int cpu);
59 static struct cpuhp_step cpuhp_bp_states[];
60 static struct cpuhp_step cpuhp_ap_states[];
63 * cpuhp_invoke_callback _ Invoke the callbacks for a given state
64 * @cpu: The cpu for which the callback should be invoked
65 * @step: The step in the state machine
66 * @cb: The callback function to invoke
68 * Called from cpu hotplug and from the state register machinery
70 static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state step,
71 int (*cb)(unsigned int))
73 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
77 trace_cpuhp_enter(cpu, st->target, step, cb);
79 trace_cpuhp_exit(cpu, st->state, step, ret);
85 /* Serializes the updates to cpu_online_mask, cpu_present_mask */
86 static DEFINE_MUTEX(cpu_add_remove_lock);
87 bool cpuhp_tasks_frozen;
88 EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen);
91 * The following two APIs (cpu_maps_update_begin/done) must be used when
92 * attempting to serialize the updates to cpu_online_mask & cpu_present_mask.
93 * The APIs cpu_notifier_register_begin/done() must be used to protect CPU
94 * hotplug callback (un)registration performed using __register_cpu_notifier()
95 * or __unregister_cpu_notifier().
97 void cpu_maps_update_begin(void)
99 mutex_lock(&cpu_add_remove_lock);
101 EXPORT_SYMBOL(cpu_notifier_register_begin);
103 void cpu_maps_update_done(void)
105 mutex_unlock(&cpu_add_remove_lock);
107 EXPORT_SYMBOL(cpu_notifier_register_done);
109 static RAW_NOTIFIER_HEAD(cpu_chain);
111 /* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
112 * Should always be manipulated under cpu_add_remove_lock
114 static int cpu_hotplug_disabled;
116 #ifdef CONFIG_HOTPLUG_CPU
119 struct task_struct *active_writer;
120 /* wait queue to wake up the active_writer */
121 wait_queue_head_t wq;
122 /* verifies that no writer will get active while readers are active */
125 * Also blocks the new readers during
126 * an ongoing cpu hotplug operation.
130 #ifdef CONFIG_DEBUG_LOCK_ALLOC
131 struct lockdep_map dep_map;
134 .active_writer = NULL,
135 .wq = __WAIT_QUEUE_HEAD_INITIALIZER(cpu_hotplug.wq),
136 .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),
137 #ifdef CONFIG_DEBUG_LOCK_ALLOC
138 .dep_map = {.name = "cpu_hotplug.lock" },
142 /* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */
143 #define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map)
144 #define cpuhp_lock_acquire_tryread() \
145 lock_map_acquire_tryread(&cpu_hotplug.dep_map)
146 #define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map)
147 #define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)
150 void get_online_cpus(void)
153 if (cpu_hotplug.active_writer == current)
155 cpuhp_lock_acquire_read();
156 mutex_lock(&cpu_hotplug.lock);
157 atomic_inc(&cpu_hotplug.refcount);
158 mutex_unlock(&cpu_hotplug.lock);
160 EXPORT_SYMBOL_GPL(get_online_cpus);
162 void put_online_cpus(void)
166 if (cpu_hotplug.active_writer == current)
169 refcount = atomic_dec_return(&cpu_hotplug.refcount);
170 if (WARN_ON(refcount < 0)) /* try to fix things up */
171 atomic_inc(&cpu_hotplug.refcount);
173 if (refcount <= 0 && waitqueue_active(&cpu_hotplug.wq))
174 wake_up(&cpu_hotplug.wq);
176 cpuhp_lock_release();
179 EXPORT_SYMBOL_GPL(put_online_cpus);
182 * This ensures that the hotplug operation can begin only when the
183 * refcount goes to zero.
185 * Note that during a cpu-hotplug operation, the new readers, if any,
186 * will be blocked by the cpu_hotplug.lock
188 * Since cpu_hotplug_begin() is always called after invoking
189 * cpu_maps_update_begin(), we can be sure that only one writer is active.
191 * Note that theoretically, there is a possibility of a livelock:
192 * - Refcount goes to zero, last reader wakes up the sleeping
194 * - Last reader unlocks the cpu_hotplug.lock.
195 * - A new reader arrives at this moment, bumps up the refcount.
196 * - The writer acquires the cpu_hotplug.lock finds the refcount
197 * non zero and goes to sleep again.
199 * However, this is very difficult to achieve in practice since
200 * get_online_cpus() not an api which is called all that often.
203 void cpu_hotplug_begin(void)
207 cpu_hotplug.active_writer = current;
208 cpuhp_lock_acquire();
211 mutex_lock(&cpu_hotplug.lock);
212 prepare_to_wait(&cpu_hotplug.wq, &wait, TASK_UNINTERRUPTIBLE);
213 if (likely(!atomic_read(&cpu_hotplug.refcount)))
215 mutex_unlock(&cpu_hotplug.lock);
218 finish_wait(&cpu_hotplug.wq, &wait);
221 void cpu_hotplug_done(void)
223 cpu_hotplug.active_writer = NULL;
224 mutex_unlock(&cpu_hotplug.lock);
225 cpuhp_lock_release();
229 * Wait for currently running CPU hotplug operations to complete (if any) and
230 * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
231 * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the
232 * hotplug path before performing hotplug operations. So acquiring that lock
233 * guarantees mutual exclusion from any currently running hotplug operations.
235 void cpu_hotplug_disable(void)
237 cpu_maps_update_begin();
238 cpu_hotplug_disabled++;
239 cpu_maps_update_done();
241 EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
243 void cpu_hotplug_enable(void)
245 cpu_maps_update_begin();
246 WARN_ON(--cpu_hotplug_disabled < 0);
247 cpu_maps_update_done();
249 EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
250 #endif /* CONFIG_HOTPLUG_CPU */
252 /* Need to know about CPUs going up/down? */
253 int register_cpu_notifier(struct notifier_block *nb)
256 cpu_maps_update_begin();
257 ret = raw_notifier_chain_register(&cpu_chain, nb);
258 cpu_maps_update_done();
262 int __register_cpu_notifier(struct notifier_block *nb)
264 return raw_notifier_chain_register(&cpu_chain, nb);
267 static int __cpu_notify(unsigned long val, unsigned int cpu, int nr_to_call,
270 unsigned long mod = cpuhp_tasks_frozen ? CPU_TASKS_FROZEN : 0;
271 void *hcpu = (void *)(long)cpu;
275 ret = __raw_notifier_call_chain(&cpu_chain, val | mod, hcpu, nr_to_call,
278 return notifier_to_errno(ret);
281 static int cpu_notify(unsigned long val, unsigned int cpu)
283 return __cpu_notify(val, cpu, -1, NULL);
286 /* Notifier wrappers for transitioning to state machine */
287 static int notify_prepare(unsigned int cpu)
292 ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls);
295 printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n",
297 __cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL);
302 static int notify_online(unsigned int cpu)
304 cpu_notify(CPU_ONLINE, cpu);
308 static int notify_starting(unsigned int cpu)
310 cpu_notify(CPU_STARTING, cpu);
314 static int bringup_cpu(unsigned int cpu)
316 struct task_struct *idle = idle_thread_get(cpu);
319 /* Arch-specific enabling code. */
320 ret = __cpu_up(cpu, idle);
322 cpu_notify(CPU_UP_CANCELED, cpu);
325 BUG_ON(!cpu_online(cpu));
329 #ifdef CONFIG_HOTPLUG_CPU
330 EXPORT_SYMBOL(register_cpu_notifier);
331 EXPORT_SYMBOL(__register_cpu_notifier);
333 void unregister_cpu_notifier(struct notifier_block *nb)
335 cpu_maps_update_begin();
336 raw_notifier_chain_unregister(&cpu_chain, nb);
337 cpu_maps_update_done();
339 EXPORT_SYMBOL(unregister_cpu_notifier);
341 void __unregister_cpu_notifier(struct notifier_block *nb)
343 raw_notifier_chain_unregister(&cpu_chain, nb);
345 EXPORT_SYMBOL(__unregister_cpu_notifier);
348 * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
351 * This function walks all processes, finds a valid mm struct for each one and
352 * then clears a corresponding bit in mm's cpumask. While this all sounds
353 * trivial, there are various non-obvious corner cases, which this function
354 * tries to solve in a safe manner.
356 * Also note that the function uses a somewhat relaxed locking scheme, so it may
357 * be called only for an already offlined CPU.
359 void clear_tasks_mm_cpumask(int cpu)
361 struct task_struct *p;
364 * This function is called after the cpu is taken down and marked
365 * offline, so its not like new tasks will ever get this cpu set in
366 * their mm mask. -- Peter Zijlstra
367 * Thus, we may use rcu_read_lock() here, instead of grabbing
368 * full-fledged tasklist_lock.
370 WARN_ON(cpu_online(cpu));
372 for_each_process(p) {
373 struct task_struct *t;
376 * Main thread might exit, but other threads may still have
377 * a valid mm. Find one.
379 t = find_lock_task_mm(p);
382 cpumask_clear_cpu(cpu, mm_cpumask(t->mm));
388 static inline void check_for_tasks(int dead_cpu)
390 struct task_struct *g, *p;
392 read_lock(&tasklist_lock);
393 for_each_process_thread(g, p) {
397 * We do the check with unlocked task_rq(p)->lock.
398 * Order the reading to do not warn about a task,
399 * which was running on this cpu in the past, and
400 * it's just been woken on another cpu.
403 if (task_cpu(p) != dead_cpu)
406 pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n",
407 p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags);
409 read_unlock(&tasklist_lock);
412 static void cpu_notify_nofail(unsigned long val, unsigned int cpu)
414 BUG_ON(cpu_notify(val, cpu));
417 static int notify_down_prepare(unsigned int cpu)
419 int err, nr_calls = 0;
421 err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls);
424 __cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL);
425 pr_warn("%s: attempt to take down CPU %u failed\n",
431 static int notify_dying(unsigned int cpu)
433 cpu_notify(CPU_DYING, cpu);
437 /* Take this CPU down. */
438 static int take_cpu_down(void *_param)
440 struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
441 enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE);
442 int err, cpu = smp_processor_id();
444 /* Ensure this CPU doesn't handle any more interrupts. */
445 err = __cpu_disable();
449 /* Invoke the former CPU_DYING callbacks */
450 for (; st->state > target; st->state--) {
451 struct cpuhp_step *step = cpuhp_ap_states + st->state;
453 cpuhp_invoke_callback(cpu, st->state, step->teardown);
455 /* Give up timekeeping duties */
456 tick_handover_do_timer();
457 /* Park the stopper thread */
458 stop_machine_park(cpu);
462 static int takedown_cpu(unsigned int cpu)
467 * By now we've cleared cpu_active_mask, wait for all preempt-disabled
468 * and RCU users of this state to go away such that all new such users
471 * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might
472 * not imply sync_sched(), so wait for both.
474 * Do sync before park smpboot threads to take care the rcu boost case.
476 if (IS_ENABLED(CONFIG_PREEMPT))
477 synchronize_rcu_mult(call_rcu, call_rcu_sched);
481 smpboot_park_threads(cpu);
484 * Prevent irq alloc/free while the dying cpu reorganizes the
485 * interrupt affinities.
490 * So now all preempt/rcu users must observe !cpu_active().
492 err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu));
494 /* CPU didn't die: tell everyone. Can't complain. */
495 cpu_notify_nofail(CPU_DOWN_FAILED, cpu);
499 BUG_ON(cpu_online(cpu));
502 * The migration_call() CPU_DYING callback will have removed all
503 * runnable tasks from the cpu, there's only the idle task left now
504 * that the migration thread is done doing the stop_machine thing.
506 * Wait for the stop thread to go away.
508 while (!per_cpu(cpu_dead_idle, cpu))
510 smp_mb(); /* Read from cpu_dead_idle before __cpu_die(). */
511 per_cpu(cpu_dead_idle, cpu) = false;
513 /* Interrupts are moved away from the dying cpu, reenable alloc/free */
516 hotplug_cpu__broadcast_tick_pull(cpu);
517 /* This actually kills the CPU. */
520 tick_cleanup_dead_cpu(cpu);
524 static int notify_dead(unsigned int cpu)
526 cpu_notify_nofail(CPU_DEAD, cpu);
527 check_for_tasks(cpu);
532 #define notify_down_prepare NULL
533 #define takedown_cpu NULL
534 #define notify_dead NULL
535 #define notify_dying NULL
538 #ifdef CONFIG_HOTPLUG_CPU
539 static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st)
541 for (st->state++; st->state < st->target; st->state++) {
542 struct cpuhp_step *step = cpuhp_bp_states + st->state;
544 if (!step->skip_onerr)
545 cpuhp_invoke_callback(cpu, st->state, step->startup);
549 /* Requires cpu_add_remove_lock to be held */
550 static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
551 enum cpuhp_state target)
553 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
554 int prev_state, ret = 0;
555 bool hasdied = false;
557 if (num_online_cpus() == 1)
560 if (!cpu_online(cpu))
565 cpuhp_tasks_frozen = tasks_frozen;
567 prev_state = st->state;
569 for (; st->state > st->target; st->state--) {
570 struct cpuhp_step *step = cpuhp_bp_states + st->state;
572 ret = cpuhp_invoke_callback(cpu, st->state, step->teardown);
574 st->target = prev_state;
575 undo_cpu_down(cpu, st);
579 hasdied = prev_state != st->state && st->state == CPUHP_OFFLINE;
582 /* This post dead nonsense must die */
584 cpu_notify_nofail(CPU_POST_DEAD, cpu);
588 static int do_cpu_down(unsigned int cpu, enum cpuhp_state target)
592 cpu_maps_update_begin();
594 if (cpu_hotplug_disabled) {
599 err = _cpu_down(cpu, 0, target);
602 cpu_maps_update_done();
605 int cpu_down(unsigned int cpu)
607 return do_cpu_down(cpu, CPUHP_OFFLINE);
609 EXPORT_SYMBOL(cpu_down);
610 #endif /*CONFIG_HOTPLUG_CPU*/
613 * Unpark per-CPU smpboot kthreads at CPU-online time.
615 static int smpboot_thread_call(struct notifier_block *nfb,
616 unsigned long action, void *hcpu)
618 int cpu = (long)hcpu;
620 switch (action & ~CPU_TASKS_FROZEN) {
622 case CPU_DOWN_FAILED:
624 smpboot_unpark_threads(cpu);
634 static struct notifier_block smpboot_thread_notifier = {
635 .notifier_call = smpboot_thread_call,
636 .priority = CPU_PRI_SMPBOOT,
639 void smpboot_thread_init(void)
641 register_cpu_notifier(&smpboot_thread_notifier);
645 * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
646 * @cpu: cpu that just started
648 * This function calls the cpu_chain notifiers with CPU_STARTING.
649 * It must be called by the arch code on the new cpu, before the new cpu
650 * enables interrupts and before the "boot" cpu returns from __cpu_up().
652 void notify_cpu_starting(unsigned int cpu)
654 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
655 enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE);
657 while (st->state < target) {
658 struct cpuhp_step *step;
661 step = cpuhp_ap_states + st->state;
662 cpuhp_invoke_callback(cpu, st->state, step->startup);
666 static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st)
668 for (st->state--; st->state > st->target; st->state--) {
669 struct cpuhp_step *step = cpuhp_bp_states + st->state;
671 if (!step->skip_onerr)
672 cpuhp_invoke_callback(cpu, st->state, step->teardown);
676 /* Requires cpu_add_remove_lock to be held */
677 static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target)
679 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
680 struct task_struct *idle;
681 int prev_state, ret = 0;
685 if (cpu_online(cpu) || !cpu_present(cpu)) {
690 /* Let it fail before we try to bring the cpu up */
691 idle = idle_thread_get(cpu);
697 cpuhp_tasks_frozen = tasks_frozen;
699 prev_state = st->state;
701 while (st->state < st->target) {
702 struct cpuhp_step *step;
705 step = cpuhp_bp_states + st->state;
706 ret = cpuhp_invoke_callback(cpu, st->state, step->startup);
708 st->target = prev_state;
709 undo_cpu_up(cpu, st);
718 static int do_cpu_up(unsigned int cpu, enum cpuhp_state target)
722 if (!cpu_possible(cpu)) {
723 pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n",
725 #if defined(CONFIG_IA64)
726 pr_err("please check additional_cpus= boot parameter\n");
731 err = try_online_node(cpu_to_node(cpu));
735 cpu_maps_update_begin();
737 if (cpu_hotplug_disabled) {
742 err = _cpu_up(cpu, 0, target);
744 cpu_maps_update_done();
748 int cpu_up(unsigned int cpu)
750 return do_cpu_up(cpu, CPUHP_ONLINE);
752 EXPORT_SYMBOL_GPL(cpu_up);
754 #ifdef CONFIG_PM_SLEEP_SMP
755 static cpumask_var_t frozen_cpus;
757 int disable_nonboot_cpus(void)
759 int cpu, first_cpu, error = 0;
761 cpu_maps_update_begin();
762 first_cpu = cpumask_first(cpu_online_mask);
764 * We take down all of the non-boot CPUs in one shot to avoid races
765 * with the userspace trying to use the CPU hotplug at the same time
767 cpumask_clear(frozen_cpus);
769 pr_info("Disabling non-boot CPUs ...\n");
770 for_each_online_cpu(cpu) {
771 if (cpu == first_cpu)
773 trace_suspend_resume(TPS("CPU_OFF"), cpu, true);
774 error = _cpu_down(cpu, 1, CPUHP_OFFLINE);
775 trace_suspend_resume(TPS("CPU_OFF"), cpu, false);
777 cpumask_set_cpu(cpu, frozen_cpus);
779 pr_err("Error taking CPU%d down: %d\n", cpu, error);
785 BUG_ON(num_online_cpus() > 1);
787 pr_err("Non-boot CPUs are not disabled\n");
790 * Make sure the CPUs won't be enabled by someone else. We need to do
791 * this even in case of failure as all disable_nonboot_cpus() users are
792 * supposed to do enable_nonboot_cpus() on the failure path.
794 cpu_hotplug_disabled++;
796 cpu_maps_update_done();
800 void __weak arch_enable_nonboot_cpus_begin(void)
804 void __weak arch_enable_nonboot_cpus_end(void)
808 void enable_nonboot_cpus(void)
812 /* Allow everyone to use the CPU hotplug again */
813 cpu_maps_update_begin();
814 WARN_ON(--cpu_hotplug_disabled < 0);
815 if (cpumask_empty(frozen_cpus))
818 pr_info("Enabling non-boot CPUs ...\n");
820 arch_enable_nonboot_cpus_begin();
822 for_each_cpu(cpu, frozen_cpus) {
823 trace_suspend_resume(TPS("CPU_ON"), cpu, true);
824 error = _cpu_up(cpu, 1, CPUHP_ONLINE);
825 trace_suspend_resume(TPS("CPU_ON"), cpu, false);
827 pr_info("CPU%d is up\n", cpu);
830 pr_warn("Error taking CPU%d up: %d\n", cpu, error);
833 arch_enable_nonboot_cpus_end();
835 cpumask_clear(frozen_cpus);
837 cpu_maps_update_done();
840 static int __init alloc_frozen_cpus(void)
842 if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO))
846 core_initcall(alloc_frozen_cpus);
849 * When callbacks for CPU hotplug notifications are being executed, we must
850 * ensure that the state of the system with respect to the tasks being frozen
851 * or not, as reported by the notification, remains unchanged *throughout the
852 * duration* of the execution of the callbacks.
853 * Hence we need to prevent the freezer from racing with regular CPU hotplug.
855 * This synchronization is implemented by mutually excluding regular CPU
856 * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
857 * Hibernate notifications.
860 cpu_hotplug_pm_callback(struct notifier_block *nb,
861 unsigned long action, void *ptr)
865 case PM_SUSPEND_PREPARE:
866 case PM_HIBERNATION_PREPARE:
867 cpu_hotplug_disable();
870 case PM_POST_SUSPEND:
871 case PM_POST_HIBERNATION:
872 cpu_hotplug_enable();
883 static int __init cpu_hotplug_pm_sync_init(void)
886 * cpu_hotplug_pm_callback has higher priority than x86
887 * bsp_pm_callback which depends on cpu_hotplug_pm_callback
888 * to disable cpu hotplug to avoid cpu hotplug race.
890 pm_notifier(cpu_hotplug_pm_callback, 0);
893 core_initcall(cpu_hotplug_pm_sync_init);
895 #endif /* CONFIG_PM_SLEEP_SMP */
897 #endif /* CONFIG_SMP */
899 /* Boot processor state steps */
900 static struct cpuhp_step cpuhp_bp_states[] = {
907 [CPUHP_CREATE_THREADS]= {
908 .name = "threads:create",
909 .startup = smpboot_create_threads,
912 [CPUHP_NOTIFY_PREPARE] = {
913 .name = "notify:prepare",
914 .startup = notify_prepare,
915 .teardown = notify_dead,
918 [CPUHP_BRINGUP_CPU] = {
919 .name = "cpu:bringup",
920 .startup = bringup_cpu,
923 [CPUHP_TEARDOWN_CPU] = {
924 .name = "cpu:teardown",
926 .teardown = takedown_cpu,
928 [CPUHP_NOTIFY_ONLINE] = {
929 .name = "notify:online",
930 .startup = notify_online,
931 .teardown = notify_down_prepare,
941 /* Application processor state steps */
942 static struct cpuhp_step cpuhp_ap_states[] = {
944 [CPUHP_AP_NOTIFY_STARTING] = {
945 .name = "notify:starting",
946 .startup = notify_starting,
947 .teardown = notify_dying,
959 * cpu_bit_bitmap[] is a special, "compressed" data structure that
960 * represents all NR_CPUS bits binary values of 1<<nr.
962 * It is used by cpumask_of() to get a constant address to a CPU
963 * mask value that has a single bit set only.
966 /* cpu_bit_bitmap[0] is empty - so we can back into it */
967 #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x))
968 #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1)
969 #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2)
970 #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4)
972 const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = {
974 MASK_DECLARE_8(0), MASK_DECLARE_8(8),
975 MASK_DECLARE_8(16), MASK_DECLARE_8(24),
976 #if BITS_PER_LONG > 32
977 MASK_DECLARE_8(32), MASK_DECLARE_8(40),
978 MASK_DECLARE_8(48), MASK_DECLARE_8(56),
981 EXPORT_SYMBOL_GPL(cpu_bit_bitmap);
983 const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
984 EXPORT_SYMBOL(cpu_all_bits);
986 #ifdef CONFIG_INIT_ALL_POSSIBLE
987 struct cpumask __cpu_possible_mask __read_mostly
990 struct cpumask __cpu_possible_mask __read_mostly;
992 EXPORT_SYMBOL(__cpu_possible_mask);
994 struct cpumask __cpu_online_mask __read_mostly;
995 EXPORT_SYMBOL(__cpu_online_mask);
997 struct cpumask __cpu_present_mask __read_mostly;
998 EXPORT_SYMBOL(__cpu_present_mask);
1000 struct cpumask __cpu_active_mask __read_mostly;
1001 EXPORT_SYMBOL(__cpu_active_mask);
1003 void init_cpu_present(const struct cpumask *src)
1005 cpumask_copy(&__cpu_present_mask, src);
1008 void init_cpu_possible(const struct cpumask *src)
1010 cpumask_copy(&__cpu_possible_mask, src);
1013 void init_cpu_online(const struct cpumask *src)
1015 cpumask_copy(&__cpu_online_mask, src);
1019 * Activate the first processor.
1021 void __init boot_cpu_init(void)
1023 int cpu = smp_processor_id();
1025 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
1026 set_cpu_online(cpu, true);
1027 set_cpu_active(cpu, true);
1028 set_cpu_present(cpu, true);
1029 set_cpu_possible(cpu, true);
1033 * Must be called _AFTER_ setting up the per_cpu areas
1035 void __init boot_cpu_state_init(void)
1037 per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE;