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[];
62 * cpuhp_invoke_callback _ Invoke the callbacks for a given state
63 * @cpu: The cpu for which the callback should be invoked
64 * @step: The step in the state machine
65 * @cb: The callback function to invoke
67 * Called from cpu hotplug and from the state register machinery
69 static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state step,
70 int (*cb)(unsigned int))
72 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
76 trace_cpuhp_enter(cpu, st->target, step, cb);
78 trace_cpuhp_exit(cpu, st->state, step, ret);
84 /* Serializes the updates to cpu_online_mask, cpu_present_mask */
85 static DEFINE_MUTEX(cpu_add_remove_lock);
86 bool cpuhp_tasks_frozen;
87 EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen);
90 * The following two APIs (cpu_maps_update_begin/done) must be used when
91 * attempting to serialize the updates to cpu_online_mask & cpu_present_mask.
92 * The APIs cpu_notifier_register_begin/done() must be used to protect CPU
93 * hotplug callback (un)registration performed using __register_cpu_notifier()
94 * or __unregister_cpu_notifier().
96 void cpu_maps_update_begin(void)
98 mutex_lock(&cpu_add_remove_lock);
100 EXPORT_SYMBOL(cpu_notifier_register_begin);
102 void cpu_maps_update_done(void)
104 mutex_unlock(&cpu_add_remove_lock);
106 EXPORT_SYMBOL(cpu_notifier_register_done);
108 static RAW_NOTIFIER_HEAD(cpu_chain);
110 /* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
111 * Should always be manipulated under cpu_add_remove_lock
113 static int cpu_hotplug_disabled;
115 #ifdef CONFIG_HOTPLUG_CPU
118 struct task_struct *active_writer;
119 /* wait queue to wake up the active_writer */
120 wait_queue_head_t wq;
121 /* verifies that no writer will get active while readers are active */
124 * Also blocks the new readers during
125 * an ongoing cpu hotplug operation.
129 #ifdef CONFIG_DEBUG_LOCK_ALLOC
130 struct lockdep_map dep_map;
133 .active_writer = NULL,
134 .wq = __WAIT_QUEUE_HEAD_INITIALIZER(cpu_hotplug.wq),
135 .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),
136 #ifdef CONFIG_DEBUG_LOCK_ALLOC
137 .dep_map = {.name = "cpu_hotplug.lock" },
141 /* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */
142 #define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map)
143 #define cpuhp_lock_acquire_tryread() \
144 lock_map_acquire_tryread(&cpu_hotplug.dep_map)
145 #define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map)
146 #define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)
149 void get_online_cpus(void)
152 if (cpu_hotplug.active_writer == current)
154 cpuhp_lock_acquire_read();
155 mutex_lock(&cpu_hotplug.lock);
156 atomic_inc(&cpu_hotplug.refcount);
157 mutex_unlock(&cpu_hotplug.lock);
159 EXPORT_SYMBOL_GPL(get_online_cpus);
161 void put_online_cpus(void)
165 if (cpu_hotplug.active_writer == current)
168 refcount = atomic_dec_return(&cpu_hotplug.refcount);
169 if (WARN_ON(refcount < 0)) /* try to fix things up */
170 atomic_inc(&cpu_hotplug.refcount);
172 if (refcount <= 0 && waitqueue_active(&cpu_hotplug.wq))
173 wake_up(&cpu_hotplug.wq);
175 cpuhp_lock_release();
178 EXPORT_SYMBOL_GPL(put_online_cpus);
181 * This ensures that the hotplug operation can begin only when the
182 * refcount goes to zero.
184 * Note that during a cpu-hotplug operation, the new readers, if any,
185 * will be blocked by the cpu_hotplug.lock
187 * Since cpu_hotplug_begin() is always called after invoking
188 * cpu_maps_update_begin(), we can be sure that only one writer is active.
190 * Note that theoretically, there is a possibility of a livelock:
191 * - Refcount goes to zero, last reader wakes up the sleeping
193 * - Last reader unlocks the cpu_hotplug.lock.
194 * - A new reader arrives at this moment, bumps up the refcount.
195 * - The writer acquires the cpu_hotplug.lock finds the refcount
196 * non zero and goes to sleep again.
198 * However, this is very difficult to achieve in practice since
199 * get_online_cpus() not an api which is called all that often.
202 void cpu_hotplug_begin(void)
206 cpu_hotplug.active_writer = current;
207 cpuhp_lock_acquire();
210 mutex_lock(&cpu_hotplug.lock);
211 prepare_to_wait(&cpu_hotplug.wq, &wait, TASK_UNINTERRUPTIBLE);
212 if (likely(!atomic_read(&cpu_hotplug.refcount)))
214 mutex_unlock(&cpu_hotplug.lock);
217 finish_wait(&cpu_hotplug.wq, &wait);
220 void cpu_hotplug_done(void)
222 cpu_hotplug.active_writer = NULL;
223 mutex_unlock(&cpu_hotplug.lock);
224 cpuhp_lock_release();
228 * Wait for currently running CPU hotplug operations to complete (if any) and
229 * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
230 * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the
231 * hotplug path before performing hotplug operations. So acquiring that lock
232 * guarantees mutual exclusion from any currently running hotplug operations.
234 void cpu_hotplug_disable(void)
236 cpu_maps_update_begin();
237 cpu_hotplug_disabled++;
238 cpu_maps_update_done();
240 EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
242 void cpu_hotplug_enable(void)
244 cpu_maps_update_begin();
245 WARN_ON(--cpu_hotplug_disabled < 0);
246 cpu_maps_update_done();
248 EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
249 #endif /* CONFIG_HOTPLUG_CPU */
251 /* Need to know about CPUs going up/down? */
252 int register_cpu_notifier(struct notifier_block *nb)
255 cpu_maps_update_begin();
256 ret = raw_notifier_chain_register(&cpu_chain, nb);
257 cpu_maps_update_done();
261 int __register_cpu_notifier(struct notifier_block *nb)
263 return raw_notifier_chain_register(&cpu_chain, nb);
266 static int __cpu_notify(unsigned long val, unsigned int cpu, int nr_to_call,
269 unsigned long mod = cpuhp_tasks_frozen ? CPU_TASKS_FROZEN : 0;
270 void *hcpu = (void *)(long)cpu;
274 ret = __raw_notifier_call_chain(&cpu_chain, val | mod, hcpu, nr_to_call,
277 return notifier_to_errno(ret);
280 static int cpu_notify(unsigned long val, unsigned int cpu)
282 return __cpu_notify(val, cpu, -1, NULL);
285 /* Notifier wrappers for transitioning to state machine */
286 static int notify_prepare(unsigned int cpu)
291 ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls);
294 printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n",
296 __cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL);
301 static int notify_online(unsigned int cpu)
303 cpu_notify(CPU_ONLINE, cpu);
307 static int bringup_cpu(unsigned int cpu)
309 struct task_struct *idle = idle_thread_get(cpu);
312 /* Arch-specific enabling code. */
313 ret = __cpu_up(cpu, idle);
315 cpu_notify(CPU_UP_CANCELED, cpu);
318 BUG_ON(!cpu_online(cpu));
322 #ifdef CONFIG_HOTPLUG_CPU
323 EXPORT_SYMBOL(register_cpu_notifier);
324 EXPORT_SYMBOL(__register_cpu_notifier);
326 void unregister_cpu_notifier(struct notifier_block *nb)
328 cpu_maps_update_begin();
329 raw_notifier_chain_unregister(&cpu_chain, nb);
330 cpu_maps_update_done();
332 EXPORT_SYMBOL(unregister_cpu_notifier);
334 void __unregister_cpu_notifier(struct notifier_block *nb)
336 raw_notifier_chain_unregister(&cpu_chain, nb);
338 EXPORT_SYMBOL(__unregister_cpu_notifier);
341 * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
344 * This function walks all processes, finds a valid mm struct for each one and
345 * then clears a corresponding bit in mm's cpumask. While this all sounds
346 * trivial, there are various non-obvious corner cases, which this function
347 * tries to solve in a safe manner.
349 * Also note that the function uses a somewhat relaxed locking scheme, so it may
350 * be called only for an already offlined CPU.
352 void clear_tasks_mm_cpumask(int cpu)
354 struct task_struct *p;
357 * This function is called after the cpu is taken down and marked
358 * offline, so its not like new tasks will ever get this cpu set in
359 * their mm mask. -- Peter Zijlstra
360 * Thus, we may use rcu_read_lock() here, instead of grabbing
361 * full-fledged tasklist_lock.
363 WARN_ON(cpu_online(cpu));
365 for_each_process(p) {
366 struct task_struct *t;
369 * Main thread might exit, but other threads may still have
370 * a valid mm. Find one.
372 t = find_lock_task_mm(p);
375 cpumask_clear_cpu(cpu, mm_cpumask(t->mm));
381 static inline void check_for_tasks(int dead_cpu)
383 struct task_struct *g, *p;
385 read_lock(&tasklist_lock);
386 for_each_process_thread(g, p) {
390 * We do the check with unlocked task_rq(p)->lock.
391 * Order the reading to do not warn about a task,
392 * which was running on this cpu in the past, and
393 * it's just been woken on another cpu.
396 if (task_cpu(p) != dead_cpu)
399 pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n",
400 p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags);
402 read_unlock(&tasklist_lock);
405 static void cpu_notify_nofail(unsigned long val, unsigned int cpu)
407 BUG_ON(cpu_notify(val, cpu));
410 static int notify_down_prepare(unsigned int cpu)
412 int err, nr_calls = 0;
414 err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls);
417 __cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL);
418 pr_warn("%s: attempt to take down CPU %u failed\n",
424 /* Take this CPU down. */
425 static int take_cpu_down(void *_param)
427 int err, cpu = smp_processor_id();
429 /* Ensure this CPU doesn't handle any more interrupts. */
430 err = __cpu_disable();
434 cpu_notify(CPU_DYING, cpu);
435 /* Give up timekeeping duties */
436 tick_handover_do_timer();
437 /* Park the stopper thread */
438 stop_machine_park(cpu);
442 static int takedown_cpu(unsigned int cpu)
447 * By now we've cleared cpu_active_mask, wait for all preempt-disabled
448 * and RCU users of this state to go away such that all new such users
451 * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might
452 * not imply sync_sched(), so wait for both.
454 * Do sync before park smpboot threads to take care the rcu boost case.
456 if (IS_ENABLED(CONFIG_PREEMPT))
457 synchronize_rcu_mult(call_rcu, call_rcu_sched);
461 smpboot_park_threads(cpu);
464 * Prevent irq alloc/free while the dying cpu reorganizes the
465 * interrupt affinities.
470 * So now all preempt/rcu users must observe !cpu_active().
472 err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu));
474 /* CPU didn't die: tell everyone. Can't complain. */
475 cpu_notify_nofail(CPU_DOWN_FAILED, cpu);
479 BUG_ON(cpu_online(cpu));
482 * The migration_call() CPU_DYING callback will have removed all
483 * runnable tasks from the cpu, there's only the idle task left now
484 * that the migration thread is done doing the stop_machine thing.
486 * Wait for the stop thread to go away.
488 while (!per_cpu(cpu_dead_idle, cpu))
490 smp_mb(); /* Read from cpu_dead_idle before __cpu_die(). */
491 per_cpu(cpu_dead_idle, cpu) = false;
493 /* Interrupts are moved away from the dying cpu, reenable alloc/free */
496 hotplug_cpu__broadcast_tick_pull(cpu);
497 /* This actually kills the CPU. */
500 tick_cleanup_dead_cpu(cpu);
504 static int notify_dead(unsigned int cpu)
506 cpu_notify_nofail(CPU_DEAD, cpu);
507 check_for_tasks(cpu);
512 #define notify_down_prepare NULL
513 #define takedown_cpu NULL
514 #define notify_dead NULL
517 #ifdef CONFIG_HOTPLUG_CPU
518 static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st)
520 for (st->state++; st->state < st->target; st->state++) {
521 struct cpuhp_step *step = cpuhp_bp_states + st->state;
523 if (!step->skip_onerr)
524 cpuhp_invoke_callback(cpu, st->state, step->startup);
528 /* Requires cpu_add_remove_lock to be held */
529 static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
531 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
532 int prev_state, ret = 0;
533 bool hasdied = false;
535 if (num_online_cpus() == 1)
538 if (!cpu_online(cpu))
543 cpuhp_tasks_frozen = tasks_frozen;
545 prev_state = st->state;
546 st->target = CPUHP_OFFLINE;
547 for (; st->state > st->target; st->state--) {
548 struct cpuhp_step *step = cpuhp_bp_states + st->state;
550 ret = cpuhp_invoke_callback(cpu, st->state, step->teardown);
552 st->target = prev_state;
553 undo_cpu_down(cpu, st);
557 hasdied = prev_state != st->state && st->state == CPUHP_OFFLINE;
560 /* This post dead nonsense must die */
562 cpu_notify_nofail(CPU_POST_DEAD, cpu);
566 int cpu_down(unsigned int cpu)
570 cpu_maps_update_begin();
572 if (cpu_hotplug_disabled) {
577 err = _cpu_down(cpu, 0);
580 cpu_maps_update_done();
583 EXPORT_SYMBOL(cpu_down);
584 #endif /*CONFIG_HOTPLUG_CPU*/
587 * Unpark per-CPU smpboot kthreads at CPU-online time.
589 static int smpboot_thread_call(struct notifier_block *nfb,
590 unsigned long action, void *hcpu)
592 int cpu = (long)hcpu;
594 switch (action & ~CPU_TASKS_FROZEN) {
596 case CPU_DOWN_FAILED:
598 smpboot_unpark_threads(cpu);
608 static struct notifier_block smpboot_thread_notifier = {
609 .notifier_call = smpboot_thread_call,
610 .priority = CPU_PRI_SMPBOOT,
613 void smpboot_thread_init(void)
615 register_cpu_notifier(&smpboot_thread_notifier);
618 static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st)
620 for (st->state--; st->state > st->target; st->state--) {
621 struct cpuhp_step *step = cpuhp_bp_states + st->state;
623 if (!step->skip_onerr)
624 cpuhp_invoke_callback(cpu, st->state, step->teardown);
628 /* Requires cpu_add_remove_lock to be held */
629 static int _cpu_up(unsigned int cpu, int tasks_frozen)
631 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
632 struct task_struct *idle;
633 int prev_state, ret = 0;
637 if (cpu_online(cpu) || !cpu_present(cpu)) {
642 /* Let it fail before we try to bring the cpu up */
643 idle = idle_thread_get(cpu);
649 cpuhp_tasks_frozen = tasks_frozen;
651 prev_state = st->state;
652 st->target = CPUHP_ONLINE;
653 while (st->state < st->target) {
654 struct cpuhp_step *step;
657 step = cpuhp_bp_states + st->state;
658 ret = cpuhp_invoke_callback(cpu, st->state, step->startup);
660 st->target = prev_state;
661 undo_cpu_up(cpu, st);
670 int cpu_up(unsigned int cpu)
674 if (!cpu_possible(cpu)) {
675 pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n",
677 #if defined(CONFIG_IA64)
678 pr_err("please check additional_cpus= boot parameter\n");
683 err = try_online_node(cpu_to_node(cpu));
687 cpu_maps_update_begin();
689 if (cpu_hotplug_disabled) {
694 err = _cpu_up(cpu, 0);
697 cpu_maps_update_done();
700 EXPORT_SYMBOL_GPL(cpu_up);
702 #ifdef CONFIG_PM_SLEEP_SMP
703 static cpumask_var_t frozen_cpus;
705 int disable_nonboot_cpus(void)
707 int cpu, first_cpu, error = 0;
709 cpu_maps_update_begin();
710 first_cpu = cpumask_first(cpu_online_mask);
712 * We take down all of the non-boot CPUs in one shot to avoid races
713 * with the userspace trying to use the CPU hotplug at the same time
715 cpumask_clear(frozen_cpus);
717 pr_info("Disabling non-boot CPUs ...\n");
718 for_each_online_cpu(cpu) {
719 if (cpu == first_cpu)
721 trace_suspend_resume(TPS("CPU_OFF"), cpu, true);
722 error = _cpu_down(cpu, 1);
723 trace_suspend_resume(TPS("CPU_OFF"), cpu, false);
725 cpumask_set_cpu(cpu, frozen_cpus);
727 pr_err("Error taking CPU%d down: %d\n", cpu, error);
733 BUG_ON(num_online_cpus() > 1);
735 pr_err("Non-boot CPUs are not disabled\n");
738 * Make sure the CPUs won't be enabled by someone else. We need to do
739 * this even in case of failure as all disable_nonboot_cpus() users are
740 * supposed to do enable_nonboot_cpus() on the failure path.
742 cpu_hotplug_disabled++;
744 cpu_maps_update_done();
748 void __weak arch_enable_nonboot_cpus_begin(void)
752 void __weak arch_enable_nonboot_cpus_end(void)
756 void enable_nonboot_cpus(void)
760 /* Allow everyone to use the CPU hotplug again */
761 cpu_maps_update_begin();
762 WARN_ON(--cpu_hotplug_disabled < 0);
763 if (cpumask_empty(frozen_cpus))
766 pr_info("Enabling non-boot CPUs ...\n");
768 arch_enable_nonboot_cpus_begin();
770 for_each_cpu(cpu, frozen_cpus) {
771 trace_suspend_resume(TPS("CPU_ON"), cpu, true);
772 error = _cpu_up(cpu, 1);
773 trace_suspend_resume(TPS("CPU_ON"), cpu, false);
775 pr_info("CPU%d is up\n", cpu);
778 pr_warn("Error taking CPU%d up: %d\n", cpu, error);
781 arch_enable_nonboot_cpus_end();
783 cpumask_clear(frozen_cpus);
785 cpu_maps_update_done();
788 static int __init alloc_frozen_cpus(void)
790 if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO))
794 core_initcall(alloc_frozen_cpus);
797 * When callbacks for CPU hotplug notifications are being executed, we must
798 * ensure that the state of the system with respect to the tasks being frozen
799 * or not, as reported by the notification, remains unchanged *throughout the
800 * duration* of the execution of the callbacks.
801 * Hence we need to prevent the freezer from racing with regular CPU hotplug.
803 * This synchronization is implemented by mutually excluding regular CPU
804 * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
805 * Hibernate notifications.
808 cpu_hotplug_pm_callback(struct notifier_block *nb,
809 unsigned long action, void *ptr)
813 case PM_SUSPEND_PREPARE:
814 case PM_HIBERNATION_PREPARE:
815 cpu_hotplug_disable();
818 case PM_POST_SUSPEND:
819 case PM_POST_HIBERNATION:
820 cpu_hotplug_enable();
831 static int __init cpu_hotplug_pm_sync_init(void)
834 * cpu_hotplug_pm_callback has higher priority than x86
835 * bsp_pm_callback which depends on cpu_hotplug_pm_callback
836 * to disable cpu hotplug to avoid cpu hotplug race.
838 pm_notifier(cpu_hotplug_pm_callback, 0);
841 core_initcall(cpu_hotplug_pm_sync_init);
843 #endif /* CONFIG_PM_SLEEP_SMP */
846 * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
847 * @cpu: cpu that just started
849 * This function calls the cpu_chain notifiers with CPU_STARTING.
850 * It must be called by the arch code on the new cpu, before the new cpu
851 * enables interrupts and before the "boot" cpu returns from __cpu_up().
853 void notify_cpu_starting(unsigned int cpu)
855 cpu_notify(CPU_STARTING, cpu);
858 #endif /* CONFIG_SMP */
860 /* Boot processor state steps */
861 static struct cpuhp_step cpuhp_bp_states[] = {
868 [CPUHP_CREATE_THREADS]= {
869 .name = "threads:create",
870 .startup = smpboot_create_threads,
873 [CPUHP_NOTIFY_PREPARE] = {
874 .name = "notify:prepare",
875 .startup = notify_prepare,
876 .teardown = notify_dead,
879 [CPUHP_BRINGUP_CPU] = {
880 .name = "cpu:bringup",
881 .startup = bringup_cpu,
882 .teardown = takedown_cpu,
885 [CPUHP_NOTIFY_ONLINE] = {
886 .name = "notify:online",
887 .startup = notify_online,
888 .teardown = notify_down_prepare,
899 * cpu_bit_bitmap[] is a special, "compressed" data structure that
900 * represents all NR_CPUS bits binary values of 1<<nr.
902 * It is used by cpumask_of() to get a constant address to a CPU
903 * mask value that has a single bit set only.
906 /* cpu_bit_bitmap[0] is empty - so we can back into it */
907 #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x))
908 #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1)
909 #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2)
910 #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4)
912 const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = {
914 MASK_DECLARE_8(0), MASK_DECLARE_8(8),
915 MASK_DECLARE_8(16), MASK_DECLARE_8(24),
916 #if BITS_PER_LONG > 32
917 MASK_DECLARE_8(32), MASK_DECLARE_8(40),
918 MASK_DECLARE_8(48), MASK_DECLARE_8(56),
921 EXPORT_SYMBOL_GPL(cpu_bit_bitmap);
923 const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
924 EXPORT_SYMBOL(cpu_all_bits);
926 #ifdef CONFIG_INIT_ALL_POSSIBLE
927 struct cpumask __cpu_possible_mask __read_mostly
930 struct cpumask __cpu_possible_mask __read_mostly;
932 EXPORT_SYMBOL(__cpu_possible_mask);
934 struct cpumask __cpu_online_mask __read_mostly;
935 EXPORT_SYMBOL(__cpu_online_mask);
937 struct cpumask __cpu_present_mask __read_mostly;
938 EXPORT_SYMBOL(__cpu_present_mask);
940 struct cpumask __cpu_active_mask __read_mostly;
941 EXPORT_SYMBOL(__cpu_active_mask);
943 void init_cpu_present(const struct cpumask *src)
945 cpumask_copy(&__cpu_present_mask, src);
948 void init_cpu_possible(const struct cpumask *src)
950 cpumask_copy(&__cpu_possible_mask, src);
953 void init_cpu_online(const struct cpumask *src)
955 cpumask_copy(&__cpu_online_mask, src);
959 * Activate the first processor.
961 void __init boot_cpu_init(void)
963 int cpu = smp_processor_id();
965 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
966 set_cpu_online(cpu, true);
967 set_cpu_active(cpu, true);
968 set_cpu_present(cpu, true);
969 set_cpu_possible(cpu, true);
973 * Must be called _AFTER_ setting up the per_cpu areas
975 void __init boot_cpu_state_init(void)
977 per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE;