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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/signal.h> | |
11 | #include <linux/sched/hotplug.h> | |
12 | #include <linux/sched/task.h> | |
13 | #include <linux/unistd.h> | |
14 | #include <linux/cpu.h> | |
15 | #include <linux/oom.h> | |
16 | #include <linux/rcupdate.h> | |
17 | #include <linux/export.h> | |
18 | #include <linux/bug.h> | |
19 | #include <linux/kthread.h> | |
20 | #include <linux/stop_machine.h> | |
21 | #include <linux/mutex.h> | |
22 | #include <linux/gfp.h> | |
23 | #include <linux/suspend.h> | |
24 | #include <linux/lockdep.h> | |
25 | #include <linux/tick.h> | |
26 | #include <linux/irq.h> | |
27 | #include <linux/smpboot.h> | |
28 | #include <linux/relay.h> | |
29 | #include <linux/slab.h> | |
30 | #include <linux/percpu-rwsem.h> | |
31 | ||
32 | #include <trace/events/power.h> | |
33 | #define CREATE_TRACE_POINTS | |
34 | #include <trace/events/cpuhp.h> | |
35 | ||
36 | #include "smpboot.h" | |
37 | ||
38 | /** | |
39 | * cpuhp_cpu_state - Per cpu hotplug state storage | |
40 | * @state: The current cpu state | |
41 | * @target: The target state | |
42 | * @thread: Pointer to the hotplug thread | |
43 | * @should_run: Thread should execute | |
44 | * @rollback: Perform a rollback | |
45 | * @single: Single callback invocation | |
46 | * @bringup: Single callback bringup or teardown selector | |
47 | * @cb_state: The state for a single callback (install/uninstall) | |
48 | * @result: Result of the operation | |
49 | * @done: Signal completion to the issuer of the task | |
50 | */ | |
51 | struct cpuhp_cpu_state { | |
52 | enum cpuhp_state state; | |
53 | enum cpuhp_state target; | |
54 | #ifdef CONFIG_SMP | |
55 | struct task_struct *thread; | |
56 | bool should_run; | |
57 | bool rollback; | |
58 | bool single; | |
59 | bool bringup; | |
60 | struct hlist_node *node; | |
61 | enum cpuhp_state cb_state; | |
62 | int result; | |
63 | struct completion done; | |
64 | #endif | |
65 | }; | |
66 | ||
67 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state); | |
68 | ||
69 | #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) | |
70 | static struct lock_class_key cpuhp_state_key; | |
71 | static struct lockdep_map cpuhp_state_lock_map = | |
72 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state", &cpuhp_state_key); | |
73 | #endif | |
74 | ||
75 | /** | |
76 | * cpuhp_step - Hotplug state machine step | |
77 | * @name: Name of the step | |
78 | * @startup: Startup function of the step | |
79 | * @teardown: Teardown function of the step | |
80 | * @skip_onerr: Do not invoke the functions on error rollback | |
81 | * Will go away once the notifiers are gone | |
82 | * @cant_stop: Bringup/teardown can't be stopped at this step | |
83 | */ | |
84 | struct cpuhp_step { | |
85 | const char *name; | |
86 | union { | |
87 | int (*single)(unsigned int cpu); | |
88 | int (*multi)(unsigned int cpu, | |
89 | struct hlist_node *node); | |
90 | } startup; | |
91 | union { | |
92 | int (*single)(unsigned int cpu); | |
93 | int (*multi)(unsigned int cpu, | |
94 | struct hlist_node *node); | |
95 | } teardown; | |
96 | struct hlist_head list; | |
97 | bool skip_onerr; | |
98 | bool cant_stop; | |
99 | bool multi_instance; | |
100 | }; | |
101 | ||
102 | static DEFINE_MUTEX(cpuhp_state_mutex); | |
103 | static struct cpuhp_step cpuhp_bp_states[]; | |
104 | static struct cpuhp_step cpuhp_ap_states[]; | |
105 | ||
106 | static bool cpuhp_is_ap_state(enum cpuhp_state state) | |
107 | { | |
108 | /* | |
109 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
110 | * purposes as that state is handled explicitly in cpu_down. | |
111 | */ | |
112 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
113 | } | |
114 | ||
115 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) | |
116 | { | |
117 | struct cpuhp_step *sp; | |
118 | ||
119 | sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states; | |
120 | return sp + state; | |
121 | } | |
122 | ||
123 | /** | |
124 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state | |
125 | * @cpu: The cpu for which the callback should be invoked | |
126 | * @step: The step in the state machine | |
127 | * @bringup: True if the bringup callback should be invoked | |
128 | * | |
129 | * Called from cpu hotplug and from the state register machinery. | |
130 | */ | |
131 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, | |
132 | bool bringup, struct hlist_node *node) | |
133 | { | |
134 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
135 | struct cpuhp_step *step = cpuhp_get_step(state); | |
136 | int (*cbm)(unsigned int cpu, struct hlist_node *node); | |
137 | int (*cb)(unsigned int cpu); | |
138 | int ret, cnt; | |
139 | ||
140 | if (!step->multi_instance) { | |
141 | cb = bringup ? step->startup.single : step->teardown.single; | |
142 | if (!cb) | |
143 | return 0; | |
144 | trace_cpuhp_enter(cpu, st->target, state, cb); | |
145 | ret = cb(cpu); | |
146 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
147 | return ret; | |
148 | } | |
149 | cbm = bringup ? step->startup.multi : step->teardown.multi; | |
150 | if (!cbm) | |
151 | return 0; | |
152 | ||
153 | /* Single invocation for instance add/remove */ | |
154 | if (node) { | |
155 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
156 | ret = cbm(cpu, node); | |
157 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
158 | return ret; | |
159 | } | |
160 | ||
161 | /* State transition. Invoke on all instances */ | |
162 | cnt = 0; | |
163 | hlist_for_each(node, &step->list) { | |
164 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
165 | ret = cbm(cpu, node); | |
166 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
167 | if (ret) | |
168 | goto err; | |
169 | cnt++; | |
170 | } | |
171 | return 0; | |
172 | err: | |
173 | /* Rollback the instances if one failed */ | |
174 | cbm = !bringup ? step->startup.multi : step->teardown.multi; | |
175 | if (!cbm) | |
176 | return ret; | |
177 | ||
178 | hlist_for_each(node, &step->list) { | |
179 | if (!cnt--) | |
180 | break; | |
181 | cbm(cpu, node); | |
182 | } | |
183 | return ret; | |
184 | } | |
185 | ||
186 | #ifdef CONFIG_SMP | |
187 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ | |
188 | static DEFINE_MUTEX(cpu_add_remove_lock); | |
189 | bool cpuhp_tasks_frozen; | |
190 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
191 | ||
192 | /* | |
193 | * The following two APIs (cpu_maps_update_begin/done) must be used when | |
194 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
195 | */ | |
196 | void cpu_maps_update_begin(void) | |
197 | { | |
198 | mutex_lock(&cpu_add_remove_lock); | |
199 | } | |
200 | ||
201 | void cpu_maps_update_done(void) | |
202 | { | |
203 | mutex_unlock(&cpu_add_remove_lock); | |
204 | } | |
205 | ||
206 | /* | |
207 | * If set, cpu_up and cpu_down will return -EBUSY and do nothing. | |
208 | * Should always be manipulated under cpu_add_remove_lock | |
209 | */ | |
210 | static int cpu_hotplug_disabled; | |
211 | ||
212 | #ifdef CONFIG_HOTPLUG_CPU | |
213 | ||
214 | DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); | |
215 | ||
216 | void cpus_read_lock(void) | |
217 | { | |
218 | percpu_down_read(&cpu_hotplug_lock); | |
219 | } | |
220 | EXPORT_SYMBOL_GPL(cpus_read_lock); | |
221 | ||
222 | void cpus_read_unlock(void) | |
223 | { | |
224 | percpu_up_read(&cpu_hotplug_lock); | |
225 | } | |
226 | EXPORT_SYMBOL_GPL(cpus_read_unlock); | |
227 | ||
228 | void cpus_write_lock(void) | |
229 | { | |
230 | percpu_down_write(&cpu_hotplug_lock); | |
231 | } | |
232 | ||
233 | void cpus_write_unlock(void) | |
234 | { | |
235 | percpu_up_write(&cpu_hotplug_lock); | |
236 | } | |
237 | ||
238 | void lockdep_assert_cpus_held(void) | |
239 | { | |
240 | percpu_rwsem_assert_held(&cpu_hotplug_lock); | |
241 | } | |
242 | ||
243 | /* | |
244 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
245 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
246 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
247 | * hotplug path before performing hotplug operations. So acquiring that lock | |
248 | * guarantees mutual exclusion from any currently running hotplug operations. | |
249 | */ | |
250 | void cpu_hotplug_disable(void) | |
251 | { | |
252 | cpu_maps_update_begin(); | |
253 | cpu_hotplug_disabled++; | |
254 | cpu_maps_update_done(); | |
255 | } | |
256 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); | |
257 | ||
258 | static void __cpu_hotplug_enable(void) | |
259 | { | |
260 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) | |
261 | return; | |
262 | cpu_hotplug_disabled--; | |
263 | } | |
264 | ||
265 | void cpu_hotplug_enable(void) | |
266 | { | |
267 | cpu_maps_update_begin(); | |
268 | __cpu_hotplug_enable(); | |
269 | cpu_maps_update_done(); | |
270 | } | |
271 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); | |
272 | #endif /* CONFIG_HOTPLUG_CPU */ | |
273 | ||
274 | static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st); | |
275 | ||
276 | static int bringup_wait_for_ap(unsigned int cpu) | |
277 | { | |
278 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
279 | ||
280 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ | |
281 | wait_for_completion(&st->done); | |
282 | if (WARN_ON_ONCE((!cpu_online(cpu)))) | |
283 | return -ECANCELED; | |
284 | ||
285 | /* Unpark the stopper thread and the hotplug thread of the target cpu */ | |
286 | stop_machine_unpark(cpu); | |
287 | kthread_unpark(st->thread); | |
288 | ||
289 | /* Should we go further up ? */ | |
290 | if (st->target > CPUHP_AP_ONLINE_IDLE) { | |
291 | __cpuhp_kick_ap_work(st); | |
292 | wait_for_completion(&st->done); | |
293 | } | |
294 | return st->result; | |
295 | } | |
296 | ||
297 | static int bringup_cpu(unsigned int cpu) | |
298 | { | |
299 | struct task_struct *idle = idle_thread_get(cpu); | |
300 | int ret; | |
301 | ||
302 | /* | |
303 | * Some architectures have to walk the irq descriptors to | |
304 | * setup the vector space for the cpu which comes online. | |
305 | * Prevent irq alloc/free across the bringup. | |
306 | */ | |
307 | irq_lock_sparse(); | |
308 | ||
309 | /* Arch-specific enabling code. */ | |
310 | ret = __cpu_up(cpu, idle); | |
311 | irq_unlock_sparse(); | |
312 | if (ret) | |
313 | return ret; | |
314 | return bringup_wait_for_ap(cpu); | |
315 | } | |
316 | ||
317 | /* | |
318 | * Hotplug state machine related functions | |
319 | */ | |
320 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) | |
321 | { | |
322 | for (st->state++; st->state < st->target; st->state++) { | |
323 | struct cpuhp_step *step = cpuhp_get_step(st->state); | |
324 | ||
325 | if (!step->skip_onerr) | |
326 | cpuhp_invoke_callback(cpu, st->state, true, NULL); | |
327 | } | |
328 | } | |
329 | ||
330 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
331 | enum cpuhp_state target) | |
332 | { | |
333 | enum cpuhp_state prev_state = st->state; | |
334 | int ret = 0; | |
335 | ||
336 | for (; st->state > target; st->state--) { | |
337 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL); | |
338 | if (ret) { | |
339 | st->target = prev_state; | |
340 | undo_cpu_down(cpu, st); | |
341 | break; | |
342 | } | |
343 | } | |
344 | return ret; | |
345 | } | |
346 | ||
347 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) | |
348 | { | |
349 | for (st->state--; st->state > st->target; st->state--) { | |
350 | struct cpuhp_step *step = cpuhp_get_step(st->state); | |
351 | ||
352 | if (!step->skip_onerr) | |
353 | cpuhp_invoke_callback(cpu, st->state, false, NULL); | |
354 | } | |
355 | } | |
356 | ||
357 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
358 | enum cpuhp_state target) | |
359 | { | |
360 | enum cpuhp_state prev_state = st->state; | |
361 | int ret = 0; | |
362 | ||
363 | while (st->state < target) { | |
364 | st->state++; | |
365 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL); | |
366 | if (ret) { | |
367 | st->target = prev_state; | |
368 | undo_cpu_up(cpu, st); | |
369 | break; | |
370 | } | |
371 | } | |
372 | return ret; | |
373 | } | |
374 | ||
375 | /* | |
376 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
377 | */ | |
378 | static void cpuhp_create(unsigned int cpu) | |
379 | { | |
380 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
381 | ||
382 | init_completion(&st->done); | |
383 | } | |
384 | ||
385 | static int cpuhp_should_run(unsigned int cpu) | |
386 | { | |
387 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
388 | ||
389 | return st->should_run; | |
390 | } | |
391 | ||
392 | /* Execute the teardown callbacks. Used to be CPU_DOWN_PREPARE */ | |
393 | static int cpuhp_ap_offline(unsigned int cpu, struct cpuhp_cpu_state *st) | |
394 | { | |
395 | enum cpuhp_state target = max((int)st->target, CPUHP_TEARDOWN_CPU); | |
396 | ||
397 | return cpuhp_down_callbacks(cpu, st, target); | |
398 | } | |
399 | ||
400 | /* Execute the online startup callbacks. Used to be CPU_ONLINE */ | |
401 | static int cpuhp_ap_online(unsigned int cpu, struct cpuhp_cpu_state *st) | |
402 | { | |
403 | return cpuhp_up_callbacks(cpu, st, st->target); | |
404 | } | |
405 | ||
406 | /* | |
407 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
408 | * callbacks when a state gets [un]installed at runtime. | |
409 | */ | |
410 | static void cpuhp_thread_fun(unsigned int cpu) | |
411 | { | |
412 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
413 | int ret = 0; | |
414 | ||
415 | /* | |
416 | * Paired with the mb() in cpuhp_kick_ap_work and | |
417 | * cpuhp_invoke_ap_callback, so the work set is consistent visible. | |
418 | */ | |
419 | smp_mb(); | |
420 | if (!st->should_run) | |
421 | return; | |
422 | ||
423 | st->should_run = false; | |
424 | ||
425 | lock_map_acquire(&cpuhp_state_lock_map); | |
426 | /* Single callback invocation for [un]install ? */ | |
427 | if (st->single) { | |
428 | if (st->cb_state < CPUHP_AP_ONLINE) { | |
429 | local_irq_disable(); | |
430 | ret = cpuhp_invoke_callback(cpu, st->cb_state, | |
431 | st->bringup, st->node); | |
432 | local_irq_enable(); | |
433 | } else { | |
434 | ret = cpuhp_invoke_callback(cpu, st->cb_state, | |
435 | st->bringup, st->node); | |
436 | } | |
437 | } else if (st->rollback) { | |
438 | BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE); | |
439 | ||
440 | undo_cpu_down(cpu, st); | |
441 | st->rollback = false; | |
442 | } else { | |
443 | /* Cannot happen .... */ | |
444 | BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE); | |
445 | ||
446 | /* Regular hotplug work */ | |
447 | if (st->state < st->target) | |
448 | ret = cpuhp_ap_online(cpu, st); | |
449 | else if (st->state > st->target) | |
450 | ret = cpuhp_ap_offline(cpu, st); | |
451 | } | |
452 | lock_map_release(&cpuhp_state_lock_map); | |
453 | st->result = ret; | |
454 | complete(&st->done); | |
455 | } | |
456 | ||
457 | /* Invoke a single callback on a remote cpu */ | |
458 | static int | |
459 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, | |
460 | struct hlist_node *node) | |
461 | { | |
462 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
463 | ||
464 | if (!cpu_online(cpu)) | |
465 | return 0; | |
466 | ||
467 | lock_map_acquire(&cpuhp_state_lock_map); | |
468 | lock_map_release(&cpuhp_state_lock_map); | |
469 | ||
470 | /* | |
471 | * If we are up and running, use the hotplug thread. For early calls | |
472 | * we invoke the thread function directly. | |
473 | */ | |
474 | if (!st->thread) | |
475 | return cpuhp_invoke_callback(cpu, state, bringup, node); | |
476 | ||
477 | st->cb_state = state; | |
478 | st->single = true; | |
479 | st->bringup = bringup; | |
480 | st->node = node; | |
481 | ||
482 | /* | |
483 | * Make sure the above stores are visible before should_run becomes | |
484 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
485 | */ | |
486 | smp_mb(); | |
487 | st->should_run = true; | |
488 | wake_up_process(st->thread); | |
489 | wait_for_completion(&st->done); | |
490 | return st->result; | |
491 | } | |
492 | ||
493 | /* Regular hotplug invocation of the AP hotplug thread */ | |
494 | static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st) | |
495 | { | |
496 | st->result = 0; | |
497 | st->single = false; | |
498 | /* | |
499 | * Make sure the above stores are visible before should_run becomes | |
500 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
501 | */ | |
502 | smp_mb(); | |
503 | st->should_run = true; | |
504 | wake_up_process(st->thread); | |
505 | } | |
506 | ||
507 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
508 | { | |
509 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
510 | enum cpuhp_state state = st->state; | |
511 | ||
512 | trace_cpuhp_enter(cpu, st->target, state, cpuhp_kick_ap_work); | |
513 | lock_map_acquire(&cpuhp_state_lock_map); | |
514 | lock_map_release(&cpuhp_state_lock_map); | |
515 | __cpuhp_kick_ap_work(st); | |
516 | wait_for_completion(&st->done); | |
517 | trace_cpuhp_exit(cpu, st->state, state, st->result); | |
518 | return st->result; | |
519 | } | |
520 | ||
521 | static struct smp_hotplug_thread cpuhp_threads = { | |
522 | .store = &cpuhp_state.thread, | |
523 | .create = &cpuhp_create, | |
524 | .thread_should_run = cpuhp_should_run, | |
525 | .thread_fn = cpuhp_thread_fun, | |
526 | .thread_comm = "cpuhp/%u", | |
527 | .selfparking = true, | |
528 | }; | |
529 | ||
530 | void __init cpuhp_threads_init(void) | |
531 | { | |
532 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
533 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
534 | } | |
535 | ||
536 | #ifdef CONFIG_HOTPLUG_CPU | |
537 | /** | |
538 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
539 | * @cpu: a CPU id | |
540 | * | |
541 | * This function walks all processes, finds a valid mm struct for each one and | |
542 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
543 | * trivial, there are various non-obvious corner cases, which this function | |
544 | * tries to solve in a safe manner. | |
545 | * | |
546 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
547 | * be called only for an already offlined CPU. | |
548 | */ | |
549 | void clear_tasks_mm_cpumask(int cpu) | |
550 | { | |
551 | struct task_struct *p; | |
552 | ||
553 | /* | |
554 | * This function is called after the cpu is taken down and marked | |
555 | * offline, so its not like new tasks will ever get this cpu set in | |
556 | * their mm mask. -- Peter Zijlstra | |
557 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
558 | * full-fledged tasklist_lock. | |
559 | */ | |
560 | WARN_ON(cpu_online(cpu)); | |
561 | rcu_read_lock(); | |
562 | for_each_process(p) { | |
563 | struct task_struct *t; | |
564 | ||
565 | /* | |
566 | * Main thread might exit, but other threads may still have | |
567 | * a valid mm. Find one. | |
568 | */ | |
569 | t = find_lock_task_mm(p); | |
570 | if (!t) | |
571 | continue; | |
572 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
573 | task_unlock(t); | |
574 | } | |
575 | rcu_read_unlock(); | |
576 | } | |
577 | ||
578 | /* Take this CPU down. */ | |
579 | static int take_cpu_down(void *_param) | |
580 | { | |
581 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
582 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
583 | int err, cpu = smp_processor_id(); | |
584 | ||
585 | /* Ensure this CPU doesn't handle any more interrupts. */ | |
586 | err = __cpu_disable(); | |
587 | if (err < 0) | |
588 | return err; | |
589 | ||
590 | /* | |
591 | * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not | |
592 | * do this step again. | |
593 | */ | |
594 | WARN_ON(st->state != CPUHP_TEARDOWN_CPU); | |
595 | st->state--; | |
596 | /* Invoke the former CPU_DYING callbacks */ | |
597 | for (; st->state > target; st->state--) | |
598 | cpuhp_invoke_callback(cpu, st->state, false, NULL); | |
599 | ||
600 | /* Give up timekeeping duties */ | |
601 | tick_handover_do_timer(); | |
602 | /* Park the stopper thread */ | |
603 | stop_machine_park(cpu); | |
604 | return 0; | |
605 | } | |
606 | ||
607 | static int takedown_cpu(unsigned int cpu) | |
608 | { | |
609 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
610 | int err; | |
611 | ||
612 | /* Park the smpboot threads */ | |
613 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); | |
614 | smpboot_park_threads(cpu); | |
615 | ||
616 | /* | |
617 | * Prevent irq alloc/free while the dying cpu reorganizes the | |
618 | * interrupt affinities. | |
619 | */ | |
620 | irq_lock_sparse(); | |
621 | ||
622 | /* | |
623 | * So now all preempt/rcu users must observe !cpu_active(). | |
624 | */ | |
625 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); | |
626 | if (err) { | |
627 | /* CPU refused to die */ | |
628 | irq_unlock_sparse(); | |
629 | /* Unpark the hotplug thread so we can rollback there */ | |
630 | kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); | |
631 | return err; | |
632 | } | |
633 | BUG_ON(cpu_online(cpu)); | |
634 | ||
635 | /* | |
636 | * The CPUHP_AP_SCHED_MIGRATE_DYING callback will have removed all | |
637 | * runnable tasks from the cpu, there's only the idle task left now | |
638 | * that the migration thread is done doing the stop_machine thing. | |
639 | * | |
640 | * Wait for the stop thread to go away. | |
641 | */ | |
642 | wait_for_completion(&st->done); | |
643 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); | |
644 | ||
645 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ | |
646 | irq_unlock_sparse(); | |
647 | ||
648 | hotplug_cpu__broadcast_tick_pull(cpu); | |
649 | /* This actually kills the CPU. */ | |
650 | __cpu_die(cpu); | |
651 | ||
652 | tick_cleanup_dead_cpu(cpu); | |
653 | return 0; | |
654 | } | |
655 | ||
656 | static void cpuhp_complete_idle_dead(void *arg) | |
657 | { | |
658 | struct cpuhp_cpu_state *st = arg; | |
659 | ||
660 | complete(&st->done); | |
661 | } | |
662 | ||
663 | void cpuhp_report_idle_dead(void) | |
664 | { | |
665 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
666 | ||
667 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
668 | rcu_report_dead(smp_processor_id()); | |
669 | st->state = CPUHP_AP_IDLE_DEAD; | |
670 | /* | |
671 | * We cannot call complete after rcu_report_dead() so we delegate it | |
672 | * to an online cpu. | |
673 | */ | |
674 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
675 | cpuhp_complete_idle_dead, st, 0); | |
676 | } | |
677 | ||
678 | #else | |
679 | #define takedown_cpu NULL | |
680 | #endif | |
681 | ||
682 | #ifdef CONFIG_HOTPLUG_CPU | |
683 | ||
684 | /* Requires cpu_add_remove_lock to be held */ | |
685 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, | |
686 | enum cpuhp_state target) | |
687 | { | |
688 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
689 | int prev_state, ret = 0; | |
690 | ||
691 | if (num_online_cpus() == 1) | |
692 | return -EBUSY; | |
693 | ||
694 | if (!cpu_present(cpu)) | |
695 | return -EINVAL; | |
696 | ||
697 | cpus_write_lock(); | |
698 | ||
699 | cpuhp_tasks_frozen = tasks_frozen; | |
700 | ||
701 | prev_state = st->state; | |
702 | st->target = target; | |
703 | /* | |
704 | * If the current CPU state is in the range of the AP hotplug thread, | |
705 | * then we need to kick the thread. | |
706 | */ | |
707 | if (st->state > CPUHP_TEARDOWN_CPU) { | |
708 | ret = cpuhp_kick_ap_work(cpu); | |
709 | /* | |
710 | * The AP side has done the error rollback already. Just | |
711 | * return the error code.. | |
712 | */ | |
713 | if (ret) | |
714 | goto out; | |
715 | ||
716 | /* | |
717 | * We might have stopped still in the range of the AP hotplug | |
718 | * thread. Nothing to do anymore. | |
719 | */ | |
720 | if (st->state > CPUHP_TEARDOWN_CPU) | |
721 | goto out; | |
722 | } | |
723 | /* | |
724 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need | |
725 | * to do the further cleanups. | |
726 | */ | |
727 | ret = cpuhp_down_callbacks(cpu, st, target); | |
728 | if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) { | |
729 | st->target = prev_state; | |
730 | st->rollback = true; | |
731 | cpuhp_kick_ap_work(cpu); | |
732 | } | |
733 | ||
734 | out: | |
735 | cpus_write_unlock(); | |
736 | return ret; | |
737 | } | |
738 | ||
739 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) | |
740 | { | |
741 | int err; | |
742 | ||
743 | cpu_maps_update_begin(); | |
744 | ||
745 | if (cpu_hotplug_disabled) { | |
746 | err = -EBUSY; | |
747 | goto out; | |
748 | } | |
749 | ||
750 | err = _cpu_down(cpu, 0, target); | |
751 | ||
752 | out: | |
753 | cpu_maps_update_done(); | |
754 | return err; | |
755 | } | |
756 | int cpu_down(unsigned int cpu) | |
757 | { | |
758 | return do_cpu_down(cpu, CPUHP_OFFLINE); | |
759 | } | |
760 | EXPORT_SYMBOL(cpu_down); | |
761 | #endif /*CONFIG_HOTPLUG_CPU*/ | |
762 | ||
763 | /** | |
764 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU | |
765 | * @cpu: cpu that just started | |
766 | * | |
767 | * It must be called by the arch code on the new cpu, before the new cpu | |
768 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
769 | */ | |
770 | void notify_cpu_starting(unsigned int cpu) | |
771 | { | |
772 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
773 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
774 | ||
775 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ | |
776 | while (st->state < target) { | |
777 | st->state++; | |
778 | cpuhp_invoke_callback(cpu, st->state, true, NULL); | |
779 | } | |
780 | } | |
781 | ||
782 | /* | |
783 | * Called from the idle task. Wake up the controlling task which brings the | |
784 | * stopper and the hotplug thread of the upcoming CPU up and then delegates | |
785 | * the rest of the online bringup to the hotplug thread. | |
786 | */ | |
787 | void cpuhp_online_idle(enum cpuhp_state state) | |
788 | { | |
789 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
790 | ||
791 | /* Happens for the boot cpu */ | |
792 | if (state != CPUHP_AP_ONLINE_IDLE) | |
793 | return; | |
794 | ||
795 | st->state = CPUHP_AP_ONLINE_IDLE; | |
796 | complete(&st->done); | |
797 | } | |
798 | ||
799 | /* Requires cpu_add_remove_lock to be held */ | |
800 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) | |
801 | { | |
802 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
803 | struct task_struct *idle; | |
804 | int ret = 0; | |
805 | ||
806 | cpus_write_lock(); | |
807 | ||
808 | if (!cpu_present(cpu)) { | |
809 | ret = -EINVAL; | |
810 | goto out; | |
811 | } | |
812 | ||
813 | /* | |
814 | * The caller of do_cpu_up might have raced with another | |
815 | * caller. Ignore it for now. | |
816 | */ | |
817 | if (st->state >= target) | |
818 | goto out; | |
819 | ||
820 | if (st->state == CPUHP_OFFLINE) { | |
821 | /* Let it fail before we try to bring the cpu up */ | |
822 | idle = idle_thread_get(cpu); | |
823 | if (IS_ERR(idle)) { | |
824 | ret = PTR_ERR(idle); | |
825 | goto out; | |
826 | } | |
827 | } | |
828 | ||
829 | cpuhp_tasks_frozen = tasks_frozen; | |
830 | ||
831 | st->target = target; | |
832 | /* | |
833 | * If the current CPU state is in the range of the AP hotplug thread, | |
834 | * then we need to kick the thread once more. | |
835 | */ | |
836 | if (st->state > CPUHP_BRINGUP_CPU) { | |
837 | ret = cpuhp_kick_ap_work(cpu); | |
838 | /* | |
839 | * The AP side has done the error rollback already. Just | |
840 | * return the error code.. | |
841 | */ | |
842 | if (ret) | |
843 | goto out; | |
844 | } | |
845 | ||
846 | /* | |
847 | * Try to reach the target state. We max out on the BP at | |
848 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is | |
849 | * responsible for bringing it up to the target state. | |
850 | */ | |
851 | target = min((int)target, CPUHP_BRINGUP_CPU); | |
852 | ret = cpuhp_up_callbacks(cpu, st, target); | |
853 | out: | |
854 | cpus_write_unlock(); | |
855 | return ret; | |
856 | } | |
857 | ||
858 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) | |
859 | { | |
860 | int err = 0; | |
861 | ||
862 | if (!cpu_possible(cpu)) { | |
863 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", | |
864 | cpu); | |
865 | #if defined(CONFIG_IA64) | |
866 | pr_err("please check additional_cpus= boot parameter\n"); | |
867 | #endif | |
868 | return -EINVAL; | |
869 | } | |
870 | ||
871 | err = try_online_node(cpu_to_node(cpu)); | |
872 | if (err) | |
873 | return err; | |
874 | ||
875 | cpu_maps_update_begin(); | |
876 | ||
877 | if (cpu_hotplug_disabled) { | |
878 | err = -EBUSY; | |
879 | goto out; | |
880 | } | |
881 | ||
882 | err = _cpu_up(cpu, 0, target); | |
883 | out: | |
884 | cpu_maps_update_done(); | |
885 | return err; | |
886 | } | |
887 | ||
888 | int cpu_up(unsigned int cpu) | |
889 | { | |
890 | return do_cpu_up(cpu, CPUHP_ONLINE); | |
891 | } | |
892 | EXPORT_SYMBOL_GPL(cpu_up); | |
893 | ||
894 | #ifdef CONFIG_PM_SLEEP_SMP | |
895 | static cpumask_var_t frozen_cpus; | |
896 | ||
897 | int freeze_secondary_cpus(int primary) | |
898 | { | |
899 | int cpu, error = 0; | |
900 | ||
901 | cpu_maps_update_begin(); | |
902 | if (!cpu_online(primary)) | |
903 | primary = cpumask_first(cpu_online_mask); | |
904 | /* | |
905 | * We take down all of the non-boot CPUs in one shot to avoid races | |
906 | * with the userspace trying to use the CPU hotplug at the same time | |
907 | */ | |
908 | cpumask_clear(frozen_cpus); | |
909 | ||
910 | pr_info("Disabling non-boot CPUs ...\n"); | |
911 | for_each_online_cpu(cpu) { | |
912 | if (cpu == primary) | |
913 | continue; | |
914 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); | |
915 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); | |
916 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); | |
917 | if (!error) | |
918 | cpumask_set_cpu(cpu, frozen_cpus); | |
919 | else { | |
920 | pr_err("Error taking CPU%d down: %d\n", cpu, error); | |
921 | break; | |
922 | } | |
923 | } | |
924 | ||
925 | if (!error) | |
926 | BUG_ON(num_online_cpus() > 1); | |
927 | else | |
928 | pr_err("Non-boot CPUs are not disabled\n"); | |
929 | ||
930 | /* | |
931 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
932 | * this even in case of failure as all disable_nonboot_cpus() users are | |
933 | * supposed to do enable_nonboot_cpus() on the failure path. | |
934 | */ | |
935 | cpu_hotplug_disabled++; | |
936 | ||
937 | cpu_maps_update_done(); | |
938 | return error; | |
939 | } | |
940 | ||
941 | void __weak arch_enable_nonboot_cpus_begin(void) | |
942 | { | |
943 | } | |
944 | ||
945 | void __weak arch_enable_nonboot_cpus_end(void) | |
946 | { | |
947 | } | |
948 | ||
949 | void enable_nonboot_cpus(void) | |
950 | { | |
951 | int cpu, error; | |
952 | ||
953 | /* Allow everyone to use the CPU hotplug again */ | |
954 | cpu_maps_update_begin(); | |
955 | __cpu_hotplug_enable(); | |
956 | if (cpumask_empty(frozen_cpus)) | |
957 | goto out; | |
958 | ||
959 | pr_info("Enabling non-boot CPUs ...\n"); | |
960 | ||
961 | arch_enable_nonboot_cpus_begin(); | |
962 | ||
963 | for_each_cpu(cpu, frozen_cpus) { | |
964 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); | |
965 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); | |
966 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); | |
967 | if (!error) { | |
968 | pr_info("CPU%d is up\n", cpu); | |
969 | continue; | |
970 | } | |
971 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); | |
972 | } | |
973 | ||
974 | arch_enable_nonboot_cpus_end(); | |
975 | ||
976 | cpumask_clear(frozen_cpus); | |
977 | out: | |
978 | cpu_maps_update_done(); | |
979 | } | |
980 | ||
981 | static int __init alloc_frozen_cpus(void) | |
982 | { | |
983 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
984 | return -ENOMEM; | |
985 | return 0; | |
986 | } | |
987 | core_initcall(alloc_frozen_cpus); | |
988 | ||
989 | /* | |
990 | * When callbacks for CPU hotplug notifications are being executed, we must | |
991 | * ensure that the state of the system with respect to the tasks being frozen | |
992 | * or not, as reported by the notification, remains unchanged *throughout the | |
993 | * duration* of the execution of the callbacks. | |
994 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
995 | * | |
996 | * This synchronization is implemented by mutually excluding regular CPU | |
997 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
998 | * Hibernate notifications. | |
999 | */ | |
1000 | static int | |
1001 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1002 | unsigned long action, void *ptr) | |
1003 | { | |
1004 | switch (action) { | |
1005 | ||
1006 | case PM_SUSPEND_PREPARE: | |
1007 | case PM_HIBERNATION_PREPARE: | |
1008 | cpu_hotplug_disable(); | |
1009 | break; | |
1010 | ||
1011 | case PM_POST_SUSPEND: | |
1012 | case PM_POST_HIBERNATION: | |
1013 | cpu_hotplug_enable(); | |
1014 | break; | |
1015 | ||
1016 | default: | |
1017 | return NOTIFY_DONE; | |
1018 | } | |
1019 | ||
1020 | return NOTIFY_OK; | |
1021 | } | |
1022 | ||
1023 | ||
1024 | static int __init cpu_hotplug_pm_sync_init(void) | |
1025 | { | |
1026 | /* | |
1027 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1028 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1029 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1030 | */ | |
1031 | pm_notifier(cpu_hotplug_pm_callback, 0); | |
1032 | return 0; | |
1033 | } | |
1034 | core_initcall(cpu_hotplug_pm_sync_init); | |
1035 | ||
1036 | #endif /* CONFIG_PM_SLEEP_SMP */ | |
1037 | ||
1038 | int __boot_cpu_id; | |
1039 | ||
1040 | #endif /* CONFIG_SMP */ | |
1041 | ||
1042 | /* Boot processor state steps */ | |
1043 | static struct cpuhp_step cpuhp_bp_states[] = { | |
1044 | [CPUHP_OFFLINE] = { | |
1045 | .name = "offline", | |
1046 | .startup.single = NULL, | |
1047 | .teardown.single = NULL, | |
1048 | }, | |
1049 | #ifdef CONFIG_SMP | |
1050 | [CPUHP_CREATE_THREADS]= { | |
1051 | .name = "threads:prepare", | |
1052 | .startup.single = smpboot_create_threads, | |
1053 | .teardown.single = NULL, | |
1054 | .cant_stop = true, | |
1055 | }, | |
1056 | [CPUHP_PERF_PREPARE] = { | |
1057 | .name = "perf:prepare", | |
1058 | .startup.single = perf_event_init_cpu, | |
1059 | .teardown.single = perf_event_exit_cpu, | |
1060 | }, | |
1061 | [CPUHP_WORKQUEUE_PREP] = { | |
1062 | .name = "workqueue:prepare", | |
1063 | .startup.single = workqueue_prepare_cpu, | |
1064 | .teardown.single = NULL, | |
1065 | }, | |
1066 | [CPUHP_HRTIMERS_PREPARE] = { | |
1067 | .name = "hrtimers:prepare", | |
1068 | .startup.single = hrtimers_prepare_cpu, | |
1069 | .teardown.single = hrtimers_dead_cpu, | |
1070 | }, | |
1071 | [CPUHP_SMPCFD_PREPARE] = { | |
1072 | .name = "smpcfd:prepare", | |
1073 | .startup.single = smpcfd_prepare_cpu, | |
1074 | .teardown.single = smpcfd_dead_cpu, | |
1075 | }, | |
1076 | [CPUHP_RELAY_PREPARE] = { | |
1077 | .name = "relay:prepare", | |
1078 | .startup.single = relay_prepare_cpu, | |
1079 | .teardown.single = NULL, | |
1080 | }, | |
1081 | [CPUHP_SLAB_PREPARE] = { | |
1082 | .name = "slab:prepare", | |
1083 | .startup.single = slab_prepare_cpu, | |
1084 | .teardown.single = slab_dead_cpu, | |
1085 | }, | |
1086 | [CPUHP_RCUTREE_PREP] = { | |
1087 | .name = "RCU/tree:prepare", | |
1088 | .startup.single = rcutree_prepare_cpu, | |
1089 | .teardown.single = rcutree_dead_cpu, | |
1090 | }, | |
1091 | /* | |
1092 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1093 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1094 | * otherwise a RCU stall occurs. | |
1095 | */ | |
1096 | [CPUHP_TIMERS_DEAD] = { | |
1097 | .name = "timers:dead", | |
1098 | .startup.single = NULL, | |
1099 | .teardown.single = timers_dead_cpu, | |
1100 | }, | |
1101 | /* Kicks the plugged cpu into life */ | |
1102 | [CPUHP_BRINGUP_CPU] = { | |
1103 | .name = "cpu:bringup", | |
1104 | .startup.single = bringup_cpu, | |
1105 | .teardown.single = NULL, | |
1106 | .cant_stop = true, | |
1107 | }, | |
1108 | [CPUHP_AP_SMPCFD_DYING] = { | |
1109 | .name = "smpcfd:dying", | |
1110 | .startup.single = NULL, | |
1111 | .teardown.single = smpcfd_dying_cpu, | |
1112 | }, | |
1113 | /* | |
1114 | * Handled on controll processor until the plugged processor manages | |
1115 | * this itself. | |
1116 | */ | |
1117 | [CPUHP_TEARDOWN_CPU] = { | |
1118 | .name = "cpu:teardown", | |
1119 | .startup.single = NULL, | |
1120 | .teardown.single = takedown_cpu, | |
1121 | .cant_stop = true, | |
1122 | }, | |
1123 | #else | |
1124 | [CPUHP_BRINGUP_CPU] = { }, | |
1125 | #endif | |
1126 | }; | |
1127 | ||
1128 | /* Application processor state steps */ | |
1129 | static struct cpuhp_step cpuhp_ap_states[] = { | |
1130 | #ifdef CONFIG_SMP | |
1131 | /* Final state before CPU kills itself */ | |
1132 | [CPUHP_AP_IDLE_DEAD] = { | |
1133 | .name = "idle:dead", | |
1134 | }, | |
1135 | /* | |
1136 | * Last state before CPU enters the idle loop to die. Transient state | |
1137 | * for synchronization. | |
1138 | */ | |
1139 | [CPUHP_AP_OFFLINE] = { | |
1140 | .name = "ap:offline", | |
1141 | .cant_stop = true, | |
1142 | }, | |
1143 | /* First state is scheduler control. Interrupts are disabled */ | |
1144 | [CPUHP_AP_SCHED_STARTING] = { | |
1145 | .name = "sched:starting", | |
1146 | .startup.single = sched_cpu_starting, | |
1147 | .teardown.single = sched_cpu_dying, | |
1148 | }, | |
1149 | [CPUHP_AP_RCUTREE_DYING] = { | |
1150 | .name = "RCU/tree:dying", | |
1151 | .startup.single = NULL, | |
1152 | .teardown.single = rcutree_dying_cpu, | |
1153 | }, | |
1154 | /* Entry state on starting. Interrupts enabled from here on. Transient | |
1155 | * state for synchronsization */ | |
1156 | [CPUHP_AP_ONLINE] = { | |
1157 | .name = "ap:online", | |
1158 | }, | |
1159 | /* Handle smpboot threads park/unpark */ | |
1160 | [CPUHP_AP_SMPBOOT_THREADS] = { | |
1161 | .name = "smpboot/threads:online", | |
1162 | .startup.single = smpboot_unpark_threads, | |
1163 | .teardown.single = NULL, | |
1164 | }, | |
1165 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { | |
1166 | .name = "irq/affinity:online", | |
1167 | .startup.single = irq_affinity_online_cpu, | |
1168 | .teardown.single = NULL, | |
1169 | }, | |
1170 | [CPUHP_AP_PERF_ONLINE] = { | |
1171 | .name = "perf:online", | |
1172 | .startup.single = perf_event_init_cpu, | |
1173 | .teardown.single = perf_event_exit_cpu, | |
1174 | }, | |
1175 | [CPUHP_AP_WORKQUEUE_ONLINE] = { | |
1176 | .name = "workqueue:online", | |
1177 | .startup.single = workqueue_online_cpu, | |
1178 | .teardown.single = workqueue_offline_cpu, | |
1179 | }, | |
1180 | [CPUHP_AP_RCUTREE_ONLINE] = { | |
1181 | .name = "RCU/tree:online", | |
1182 | .startup.single = rcutree_online_cpu, | |
1183 | .teardown.single = rcutree_offline_cpu, | |
1184 | }, | |
1185 | #endif | |
1186 | /* | |
1187 | * The dynamically registered state space is here | |
1188 | */ | |
1189 | ||
1190 | #ifdef CONFIG_SMP | |
1191 | /* Last state is scheduler control setting the cpu active */ | |
1192 | [CPUHP_AP_ACTIVE] = { | |
1193 | .name = "sched:active", | |
1194 | .startup.single = sched_cpu_activate, | |
1195 | .teardown.single = sched_cpu_deactivate, | |
1196 | }, | |
1197 | #endif | |
1198 | ||
1199 | /* CPU is fully up and running. */ | |
1200 | [CPUHP_ONLINE] = { | |
1201 | .name = "online", | |
1202 | .startup.single = NULL, | |
1203 | .teardown.single = NULL, | |
1204 | }, | |
1205 | }; | |
1206 | ||
1207 | /* Sanity check for callbacks */ | |
1208 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1209 | { | |
1210 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1211 | return -EINVAL; | |
1212 | return 0; | |
1213 | } | |
1214 | ||
1215 | /* | |
1216 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1217 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1218 | * by having no name assigned. | |
1219 | */ | |
1220 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1221 | { | |
1222 | enum cpuhp_state i, end; | |
1223 | struct cpuhp_step *step; | |
1224 | ||
1225 | switch (state) { | |
1226 | case CPUHP_AP_ONLINE_DYN: | |
1227 | step = cpuhp_ap_states + CPUHP_AP_ONLINE_DYN; | |
1228 | end = CPUHP_AP_ONLINE_DYN_END; | |
1229 | break; | |
1230 | case CPUHP_BP_PREPARE_DYN: | |
1231 | step = cpuhp_bp_states + CPUHP_BP_PREPARE_DYN; | |
1232 | end = CPUHP_BP_PREPARE_DYN_END; | |
1233 | break; | |
1234 | default: | |
1235 | return -EINVAL; | |
1236 | } | |
1237 | ||
1238 | for (i = state; i <= end; i++, step++) { | |
1239 | if (!step->name) | |
1240 | return i; | |
1241 | } | |
1242 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1243 | return -ENOSPC; | |
1244 | } | |
1245 | ||
1246 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1247 | int (*startup)(unsigned int cpu), | |
1248 | int (*teardown)(unsigned int cpu), | |
1249 | bool multi_instance) | |
1250 | { | |
1251 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1252 | struct cpuhp_step *sp; | |
1253 | int ret = 0; | |
1254 | ||
1255 | /* | |
1256 | * If name is NULL, then the state gets removed. | |
1257 | * | |
1258 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on | |
1259 | * the first allocation from these dynamic ranges, so the removal | |
1260 | * would trigger a new allocation and clear the wrong (already | |
1261 | * empty) state, leaving the callbacks of the to be cleared state | |
1262 | * dangling, which causes wreckage on the next hotplug operation. | |
1263 | */ | |
1264 | if (name && (state == CPUHP_AP_ONLINE_DYN || | |
1265 | state == CPUHP_BP_PREPARE_DYN)) { | |
1266 | ret = cpuhp_reserve_state(state); | |
1267 | if (ret < 0) | |
1268 | return ret; | |
1269 | state = ret; | |
1270 | } | |
1271 | sp = cpuhp_get_step(state); | |
1272 | if (name && sp->name) | |
1273 | return -EBUSY; | |
1274 | ||
1275 | sp->startup.single = startup; | |
1276 | sp->teardown.single = teardown; | |
1277 | sp->name = name; | |
1278 | sp->multi_instance = multi_instance; | |
1279 | INIT_HLIST_HEAD(&sp->list); | |
1280 | return ret; | |
1281 | } | |
1282 | ||
1283 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1284 | { | |
1285 | return cpuhp_get_step(state)->teardown.single; | |
1286 | } | |
1287 | ||
1288 | /* | |
1289 | * Call the startup/teardown function for a step either on the AP or | |
1290 | * on the current CPU. | |
1291 | */ | |
1292 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, | |
1293 | struct hlist_node *node) | |
1294 | { | |
1295 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1296 | int ret; | |
1297 | ||
1298 | if ((bringup && !sp->startup.single) || | |
1299 | (!bringup && !sp->teardown.single)) | |
1300 | return 0; | |
1301 | /* | |
1302 | * The non AP bound callbacks can fail on bringup. On teardown | |
1303 | * e.g. module removal we crash for now. | |
1304 | */ | |
1305 | #ifdef CONFIG_SMP | |
1306 | if (cpuhp_is_ap_state(state)) | |
1307 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); | |
1308 | else | |
1309 | ret = cpuhp_invoke_callback(cpu, state, bringup, node); | |
1310 | #else | |
1311 | ret = cpuhp_invoke_callback(cpu, state, bringup, node); | |
1312 | #endif | |
1313 | BUG_ON(ret && !bringup); | |
1314 | return ret; | |
1315 | } | |
1316 | ||
1317 | /* | |
1318 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1319 | * | |
1320 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1321 | */ | |
1322 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
1323 | struct hlist_node *node) | |
1324 | { | |
1325 | int cpu; | |
1326 | ||
1327 | /* Roll back the already executed steps on the other cpus */ | |
1328 | for_each_present_cpu(cpu) { | |
1329 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1330 | int cpustate = st->state; | |
1331 | ||
1332 | if (cpu >= failedcpu) | |
1333 | break; | |
1334 | ||
1335 | /* Did we invoke the startup call on that cpu ? */ | |
1336 | if (cpustate >= state) | |
1337 | cpuhp_issue_call(cpu, state, false, node); | |
1338 | } | |
1339 | } | |
1340 | ||
1341 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, | |
1342 | struct hlist_node *node, | |
1343 | bool invoke) | |
1344 | { | |
1345 | struct cpuhp_step *sp; | |
1346 | int cpu; | |
1347 | int ret; | |
1348 | ||
1349 | lockdep_assert_cpus_held(); | |
1350 | ||
1351 | sp = cpuhp_get_step(state); | |
1352 | if (sp->multi_instance == false) | |
1353 | return -EINVAL; | |
1354 | ||
1355 | mutex_lock(&cpuhp_state_mutex); | |
1356 | ||
1357 | if (!invoke || !sp->startup.multi) | |
1358 | goto add_node; | |
1359 | ||
1360 | /* | |
1361 | * Try to call the startup callback for each present cpu | |
1362 | * depending on the hotplug state of the cpu. | |
1363 | */ | |
1364 | for_each_present_cpu(cpu) { | |
1365 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1366 | int cpustate = st->state; | |
1367 | ||
1368 | if (cpustate < state) | |
1369 | continue; | |
1370 | ||
1371 | ret = cpuhp_issue_call(cpu, state, true, node); | |
1372 | if (ret) { | |
1373 | if (sp->teardown.multi) | |
1374 | cpuhp_rollback_install(cpu, state, node); | |
1375 | goto unlock; | |
1376 | } | |
1377 | } | |
1378 | add_node: | |
1379 | ret = 0; | |
1380 | hlist_add_head(node, &sp->list); | |
1381 | unlock: | |
1382 | mutex_unlock(&cpuhp_state_mutex); | |
1383 | return ret; | |
1384 | } | |
1385 | ||
1386 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
1387 | bool invoke) | |
1388 | { | |
1389 | int ret; | |
1390 | ||
1391 | cpus_read_lock(); | |
1392 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); | |
1393 | cpus_read_unlock(); | |
1394 | return ret; | |
1395 | } | |
1396 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
1397 | ||
1398 | /** | |
1399 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state | |
1400 | * @state: The state to setup | |
1401 | * @invoke: If true, the startup function is invoked for cpus where | |
1402 | * cpu state >= @state | |
1403 | * @startup: startup callback function | |
1404 | * @teardown: teardown callback function | |
1405 | * @multi_instance: State is set up for multiple instances which get | |
1406 | * added afterwards. | |
1407 | * | |
1408 | * The caller needs to hold cpus read locked while calling this function. | |
1409 | * Returns: | |
1410 | * On success: | |
1411 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN | |
1412 | * 0 for all other states | |
1413 | * On failure: proper (negative) error code | |
1414 | */ | |
1415 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, | |
1416 | const char *name, bool invoke, | |
1417 | int (*startup)(unsigned int cpu), | |
1418 | int (*teardown)(unsigned int cpu), | |
1419 | bool multi_instance) | |
1420 | { | |
1421 | int cpu, ret = 0; | |
1422 | bool dynstate; | |
1423 | ||
1424 | lockdep_assert_cpus_held(); | |
1425 | ||
1426 | if (cpuhp_cb_check(state) || !name) | |
1427 | return -EINVAL; | |
1428 | ||
1429 | mutex_lock(&cpuhp_state_mutex); | |
1430 | ||
1431 | ret = cpuhp_store_callbacks(state, name, startup, teardown, | |
1432 | multi_instance); | |
1433 | ||
1434 | dynstate = state == CPUHP_AP_ONLINE_DYN; | |
1435 | if (ret > 0 && dynstate) { | |
1436 | state = ret; | |
1437 | ret = 0; | |
1438 | } | |
1439 | ||
1440 | if (ret || !invoke || !startup) | |
1441 | goto out; | |
1442 | ||
1443 | /* | |
1444 | * Try to call the startup callback for each present cpu | |
1445 | * depending on the hotplug state of the cpu. | |
1446 | */ | |
1447 | for_each_present_cpu(cpu) { | |
1448 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1449 | int cpustate = st->state; | |
1450 | ||
1451 | if (cpustate < state) | |
1452 | continue; | |
1453 | ||
1454 | ret = cpuhp_issue_call(cpu, state, true, NULL); | |
1455 | if (ret) { | |
1456 | if (teardown) | |
1457 | cpuhp_rollback_install(cpu, state, NULL); | |
1458 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
1459 | goto out; | |
1460 | } | |
1461 | } | |
1462 | out: | |
1463 | mutex_unlock(&cpuhp_state_mutex); | |
1464 | /* | |
1465 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
1466 | * dynamically allocated state in case of success. | |
1467 | */ | |
1468 | if (!ret && dynstate) | |
1469 | return state; | |
1470 | return ret; | |
1471 | } | |
1472 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); | |
1473 | ||
1474 | int __cpuhp_setup_state(enum cpuhp_state state, | |
1475 | const char *name, bool invoke, | |
1476 | int (*startup)(unsigned int cpu), | |
1477 | int (*teardown)(unsigned int cpu), | |
1478 | bool multi_instance) | |
1479 | { | |
1480 | int ret; | |
1481 | ||
1482 | cpus_read_lock(); | |
1483 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, | |
1484 | teardown, multi_instance); | |
1485 | cpus_read_unlock(); | |
1486 | return ret; | |
1487 | } | |
1488 | EXPORT_SYMBOL(__cpuhp_setup_state); | |
1489 | ||
1490 | int __cpuhp_state_remove_instance(enum cpuhp_state state, | |
1491 | struct hlist_node *node, bool invoke) | |
1492 | { | |
1493 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1494 | int cpu; | |
1495 | ||
1496 | BUG_ON(cpuhp_cb_check(state)); | |
1497 | ||
1498 | if (!sp->multi_instance) | |
1499 | return -EINVAL; | |
1500 | ||
1501 | cpus_read_lock(); | |
1502 | mutex_lock(&cpuhp_state_mutex); | |
1503 | ||
1504 | if (!invoke || !cpuhp_get_teardown_cb(state)) | |
1505 | goto remove; | |
1506 | /* | |
1507 | * Call the teardown callback for each present cpu depending | |
1508 | * on the hotplug state of the cpu. This function is not | |
1509 | * allowed to fail currently! | |
1510 | */ | |
1511 | for_each_present_cpu(cpu) { | |
1512 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1513 | int cpustate = st->state; | |
1514 | ||
1515 | if (cpustate >= state) | |
1516 | cpuhp_issue_call(cpu, state, false, node); | |
1517 | } | |
1518 | ||
1519 | remove: | |
1520 | hlist_del(node); | |
1521 | mutex_unlock(&cpuhp_state_mutex); | |
1522 | cpus_read_unlock(); | |
1523 | ||
1524 | return 0; | |
1525 | } | |
1526 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
1527 | ||
1528 | /** | |
1529 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state | |
1530 | * @state: The state to remove | |
1531 | * @invoke: If true, the teardown function is invoked for cpus where | |
1532 | * cpu state >= @state | |
1533 | * | |
1534 | * The caller needs to hold cpus read locked while calling this function. | |
1535 | * The teardown callback is currently not allowed to fail. Think | |
1536 | * about module removal! | |
1537 | */ | |
1538 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) | |
1539 | { | |
1540 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1541 | int cpu; | |
1542 | ||
1543 | BUG_ON(cpuhp_cb_check(state)); | |
1544 | ||
1545 | lockdep_assert_cpus_held(); | |
1546 | ||
1547 | mutex_lock(&cpuhp_state_mutex); | |
1548 | if (sp->multi_instance) { | |
1549 | WARN(!hlist_empty(&sp->list), | |
1550 | "Error: Removing state %d which has instances left.\n", | |
1551 | state); | |
1552 | goto remove; | |
1553 | } | |
1554 | ||
1555 | if (!invoke || !cpuhp_get_teardown_cb(state)) | |
1556 | goto remove; | |
1557 | ||
1558 | /* | |
1559 | * Call the teardown callback for each present cpu depending | |
1560 | * on the hotplug state of the cpu. This function is not | |
1561 | * allowed to fail currently! | |
1562 | */ | |
1563 | for_each_present_cpu(cpu) { | |
1564 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1565 | int cpustate = st->state; | |
1566 | ||
1567 | if (cpustate >= state) | |
1568 | cpuhp_issue_call(cpu, state, false, NULL); | |
1569 | } | |
1570 | remove: | |
1571 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
1572 | mutex_unlock(&cpuhp_state_mutex); | |
1573 | } | |
1574 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); | |
1575 | ||
1576 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
1577 | { | |
1578 | cpus_read_lock(); | |
1579 | __cpuhp_remove_state_cpuslocked(state, invoke); | |
1580 | cpus_read_unlock(); | |
1581 | } | |
1582 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
1583 | ||
1584 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) | |
1585 | static ssize_t show_cpuhp_state(struct device *dev, | |
1586 | struct device_attribute *attr, char *buf) | |
1587 | { | |
1588 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1589 | ||
1590 | return sprintf(buf, "%d\n", st->state); | |
1591 | } | |
1592 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
1593 | ||
1594 | static ssize_t write_cpuhp_target(struct device *dev, | |
1595 | struct device_attribute *attr, | |
1596 | const char *buf, size_t count) | |
1597 | { | |
1598 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1599 | struct cpuhp_step *sp; | |
1600 | int target, ret; | |
1601 | ||
1602 | ret = kstrtoint(buf, 10, &target); | |
1603 | if (ret) | |
1604 | return ret; | |
1605 | ||
1606 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
1607 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
1608 | return -EINVAL; | |
1609 | #else | |
1610 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
1611 | return -EINVAL; | |
1612 | #endif | |
1613 | ||
1614 | ret = lock_device_hotplug_sysfs(); | |
1615 | if (ret) | |
1616 | return ret; | |
1617 | ||
1618 | mutex_lock(&cpuhp_state_mutex); | |
1619 | sp = cpuhp_get_step(target); | |
1620 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
1621 | mutex_unlock(&cpuhp_state_mutex); | |
1622 | if (ret) | |
1623 | goto out; | |
1624 | ||
1625 | if (st->state < target) | |
1626 | ret = do_cpu_up(dev->id, target); | |
1627 | else | |
1628 | ret = do_cpu_down(dev->id, target); | |
1629 | out: | |
1630 | unlock_device_hotplug(); | |
1631 | return ret ? ret : count; | |
1632 | } | |
1633 | ||
1634 | static ssize_t show_cpuhp_target(struct device *dev, | |
1635 | struct device_attribute *attr, char *buf) | |
1636 | { | |
1637 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1638 | ||
1639 | return sprintf(buf, "%d\n", st->target); | |
1640 | } | |
1641 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); | |
1642 | ||
1643 | static struct attribute *cpuhp_cpu_attrs[] = { | |
1644 | &dev_attr_state.attr, | |
1645 | &dev_attr_target.attr, | |
1646 | NULL | |
1647 | }; | |
1648 | ||
1649 | static const struct attribute_group cpuhp_cpu_attr_group = { | |
1650 | .attrs = cpuhp_cpu_attrs, | |
1651 | .name = "hotplug", | |
1652 | NULL | |
1653 | }; | |
1654 | ||
1655 | static ssize_t show_cpuhp_states(struct device *dev, | |
1656 | struct device_attribute *attr, char *buf) | |
1657 | { | |
1658 | ssize_t cur, res = 0; | |
1659 | int i; | |
1660 | ||
1661 | mutex_lock(&cpuhp_state_mutex); | |
1662 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { | |
1663 | struct cpuhp_step *sp = cpuhp_get_step(i); | |
1664 | ||
1665 | if (sp->name) { | |
1666 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
1667 | buf += cur; | |
1668 | res += cur; | |
1669 | } | |
1670 | } | |
1671 | mutex_unlock(&cpuhp_state_mutex); | |
1672 | return res; | |
1673 | } | |
1674 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
1675 | ||
1676 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
1677 | &dev_attr_states.attr, | |
1678 | NULL | |
1679 | }; | |
1680 | ||
1681 | static const struct attribute_group cpuhp_cpu_root_attr_group = { | |
1682 | .attrs = cpuhp_cpu_root_attrs, | |
1683 | .name = "hotplug", | |
1684 | NULL | |
1685 | }; | |
1686 | ||
1687 | static int __init cpuhp_sysfs_init(void) | |
1688 | { | |
1689 | int cpu, ret; | |
1690 | ||
1691 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, | |
1692 | &cpuhp_cpu_root_attr_group); | |
1693 | if (ret) | |
1694 | return ret; | |
1695 | ||
1696 | for_each_possible_cpu(cpu) { | |
1697 | struct device *dev = get_cpu_device(cpu); | |
1698 | ||
1699 | if (!dev) | |
1700 | continue; | |
1701 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
1702 | if (ret) | |
1703 | return ret; | |
1704 | } | |
1705 | return 0; | |
1706 | } | |
1707 | device_initcall(cpuhp_sysfs_init); | |
1708 | #endif | |
1709 | ||
1710 | /* | |
1711 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
1712 | * represents all NR_CPUS bits binary values of 1<<nr. | |
1713 | * | |
1714 | * It is used by cpumask_of() to get a constant address to a CPU | |
1715 | * mask value that has a single bit set only. | |
1716 | */ | |
1717 | ||
1718 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ | |
1719 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) | |
1720 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) | |
1721 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
1722 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
1723 | ||
1724 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { | |
1725 | ||
1726 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
1727 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
1728 | #if BITS_PER_LONG > 32 | |
1729 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
1730 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
1731 | #endif | |
1732 | }; | |
1733 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); | |
1734 | ||
1735 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
1736 | EXPORT_SYMBOL(cpu_all_bits); | |
1737 | ||
1738 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
1739 | struct cpumask __cpu_possible_mask __read_mostly | |
1740 | = {CPU_BITS_ALL}; | |
1741 | #else | |
1742 | struct cpumask __cpu_possible_mask __read_mostly; | |
1743 | #endif | |
1744 | EXPORT_SYMBOL(__cpu_possible_mask); | |
1745 | ||
1746 | struct cpumask __cpu_online_mask __read_mostly; | |
1747 | EXPORT_SYMBOL(__cpu_online_mask); | |
1748 | ||
1749 | struct cpumask __cpu_present_mask __read_mostly; | |
1750 | EXPORT_SYMBOL(__cpu_present_mask); | |
1751 | ||
1752 | struct cpumask __cpu_active_mask __read_mostly; | |
1753 | EXPORT_SYMBOL(__cpu_active_mask); | |
1754 | ||
1755 | void init_cpu_present(const struct cpumask *src) | |
1756 | { | |
1757 | cpumask_copy(&__cpu_present_mask, src); | |
1758 | } | |
1759 | ||
1760 | void init_cpu_possible(const struct cpumask *src) | |
1761 | { | |
1762 | cpumask_copy(&__cpu_possible_mask, src); | |
1763 | } | |
1764 | ||
1765 | void init_cpu_online(const struct cpumask *src) | |
1766 | { | |
1767 | cpumask_copy(&__cpu_online_mask, src); | |
1768 | } | |
1769 | ||
1770 | /* | |
1771 | * Activate the first processor. | |
1772 | */ | |
1773 | void __init boot_cpu_init(void) | |
1774 | { | |
1775 | int cpu = smp_processor_id(); | |
1776 | ||
1777 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
1778 | set_cpu_online(cpu, true); | |
1779 | set_cpu_active(cpu, true); | |
1780 | set_cpu_present(cpu, true); | |
1781 | set_cpu_possible(cpu, true); | |
1782 | ||
1783 | #ifdef CONFIG_SMP | |
1784 | __boot_cpu_id = cpu; | |
1785 | #endif | |
1786 | } | |
1787 | ||
1788 | /* | |
1789 | * Must be called _AFTER_ setting up the per_cpu areas | |
1790 | */ | |
1791 | void __init boot_cpu_state_init(void) | |
1792 | { | |
1793 | per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE; | |
1794 | } |