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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.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> | |
25 | #include <linux/smpboot.h> | |
26 | #include <linux/relay.h> | |
27 | #include <linux/slab.h> | |
28 | ||
29 | #include <trace/events/power.h> | |
30 | #define CREATE_TRACE_POINTS | |
31 | #include <trace/events/cpuhp.h> | |
32 | ||
33 | #include "smpboot.h" | |
34 | ||
35 | /** | |
36 | * cpuhp_cpu_state - Per cpu hotplug state storage | |
37 | * @state: The current cpu state | |
38 | * @target: The target state | |
39 | * @thread: Pointer to the hotplug thread | |
40 | * @should_run: Thread should execute | |
41 | * @rollback: Perform a rollback | |
42 | * @single: Single callback invocation | |
43 | * @bringup: Single callback bringup or teardown selector | |
44 | * @cb_state: The state for a single callback (install/uninstall) | |
45 | * @result: Result of the operation | |
46 | * @done: Signal completion to the issuer of the task | |
47 | */ | |
48 | struct cpuhp_cpu_state { | |
49 | enum cpuhp_state state; | |
50 | enum cpuhp_state target; | |
51 | #ifdef CONFIG_SMP | |
52 | struct task_struct *thread; | |
53 | bool should_run; | |
54 | bool rollback; | |
55 | bool single; | |
56 | bool bringup; | |
57 | struct hlist_node *node; | |
58 | enum cpuhp_state cb_state; | |
59 | int result; | |
60 | struct completion done; | |
61 | #endif | |
62 | }; | |
63 | ||
64 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state); | |
65 | ||
66 | /** | |
67 | * cpuhp_step - Hotplug state machine step | |
68 | * @name: Name of the step | |
69 | * @startup: Startup function of the step | |
70 | * @teardown: Teardown function of the step | |
71 | * @skip_onerr: Do not invoke the functions on error rollback | |
72 | * Will go away once the notifiers are gone | |
73 | * @cant_stop: Bringup/teardown can't be stopped at this step | |
74 | */ | |
75 | struct cpuhp_step { | |
76 | const char *name; | |
77 | union { | |
78 | int (*single)(unsigned int cpu); | |
79 | int (*multi)(unsigned int cpu, | |
80 | struct hlist_node *node); | |
81 | } startup; | |
82 | union { | |
83 | int (*single)(unsigned int cpu); | |
84 | int (*multi)(unsigned int cpu, | |
85 | struct hlist_node *node); | |
86 | } teardown; | |
87 | struct hlist_head list; | |
88 | bool skip_onerr; | |
89 | bool cant_stop; | |
90 | bool multi_instance; | |
91 | }; | |
92 | ||
93 | static DEFINE_MUTEX(cpuhp_state_mutex); | |
94 | static struct cpuhp_step cpuhp_bp_states[]; | |
95 | static struct cpuhp_step cpuhp_ap_states[]; | |
96 | ||
97 | static bool cpuhp_is_ap_state(enum cpuhp_state state) | |
98 | { | |
99 | /* | |
100 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
101 | * purposes as that state is handled explicitly in cpu_down. | |
102 | */ | |
103 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
104 | } | |
105 | ||
106 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) | |
107 | { | |
108 | struct cpuhp_step *sp; | |
109 | ||
110 | sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states; | |
111 | return sp + state; | |
112 | } | |
113 | ||
114 | /** | |
115 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state | |
116 | * @cpu: The cpu for which the callback should be invoked | |
117 | * @step: The step in the state machine | |
118 | * @bringup: True if the bringup callback should be invoked | |
119 | * | |
120 | * Called from cpu hotplug and from the state register machinery. | |
121 | */ | |
122 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, | |
123 | bool bringup, struct hlist_node *node) | |
124 | { | |
125 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
126 | struct cpuhp_step *step = cpuhp_get_step(state); | |
127 | int (*cbm)(unsigned int cpu, struct hlist_node *node); | |
128 | int (*cb)(unsigned int cpu); | |
129 | int ret, cnt; | |
130 | ||
131 | if (!step->multi_instance) { | |
132 | cb = bringup ? step->startup.single : step->teardown.single; | |
133 | if (!cb) | |
134 | return 0; | |
135 | trace_cpuhp_enter(cpu, st->target, state, cb); | |
136 | ret = cb(cpu); | |
137 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
138 | return ret; | |
139 | } | |
140 | cbm = bringup ? step->startup.multi : step->teardown.multi; | |
141 | if (!cbm) | |
142 | return 0; | |
143 | ||
144 | /* Single invocation for instance add/remove */ | |
145 | if (node) { | |
146 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
147 | ret = cbm(cpu, node); | |
148 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
149 | return ret; | |
150 | } | |
151 | ||
152 | /* State transition. Invoke on all instances */ | |
153 | cnt = 0; | |
154 | hlist_for_each(node, &step->list) { | |
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 | if (ret) | |
159 | goto err; | |
160 | cnt++; | |
161 | } | |
162 | return 0; | |
163 | err: | |
164 | /* Rollback the instances if one failed */ | |
165 | cbm = !bringup ? step->startup.multi : step->teardown.multi; | |
166 | if (!cbm) | |
167 | return ret; | |
168 | ||
169 | hlist_for_each(node, &step->list) { | |
170 | if (!cnt--) | |
171 | break; | |
172 | cbm(cpu, node); | |
173 | } | |
174 | return ret; | |
175 | } | |
176 | ||
177 | #ifdef CONFIG_SMP | |
178 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ | |
179 | static DEFINE_MUTEX(cpu_add_remove_lock); | |
180 | bool cpuhp_tasks_frozen; | |
181 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
182 | ||
183 | /* | |
184 | * The following two APIs (cpu_maps_update_begin/done) must be used when | |
185 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
186 | */ | |
187 | void cpu_maps_update_begin(void) | |
188 | { | |
189 | mutex_lock(&cpu_add_remove_lock); | |
190 | } | |
191 | ||
192 | void cpu_maps_update_done(void) | |
193 | { | |
194 | mutex_unlock(&cpu_add_remove_lock); | |
195 | } | |
196 | ||
197 | /* If set, cpu_up and cpu_down will return -EBUSY and do nothing. | |
198 | * Should always be manipulated under cpu_add_remove_lock | |
199 | */ | |
200 | static int cpu_hotplug_disabled; | |
201 | ||
202 | #ifdef CONFIG_HOTPLUG_CPU | |
203 | ||
204 | static struct { | |
205 | struct task_struct *active_writer; | |
206 | /* wait queue to wake up the active_writer */ | |
207 | wait_queue_head_t wq; | |
208 | /* verifies that no writer will get active while readers are active */ | |
209 | struct mutex lock; | |
210 | /* | |
211 | * Also blocks the new readers during | |
212 | * an ongoing cpu hotplug operation. | |
213 | */ | |
214 | atomic_t refcount; | |
215 | ||
216 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
217 | struct lockdep_map dep_map; | |
218 | #endif | |
219 | } cpu_hotplug = { | |
220 | .active_writer = NULL, | |
221 | .wq = __WAIT_QUEUE_HEAD_INITIALIZER(cpu_hotplug.wq), | |
222 | .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock), | |
223 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
224 | .dep_map = STATIC_LOCKDEP_MAP_INIT("cpu_hotplug.dep_map", &cpu_hotplug.dep_map), | |
225 | #endif | |
226 | }; | |
227 | ||
228 | /* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */ | |
229 | #define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map) | |
230 | #define cpuhp_lock_acquire_tryread() \ | |
231 | lock_map_acquire_tryread(&cpu_hotplug.dep_map) | |
232 | #define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map) | |
233 | #define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map) | |
234 | ||
235 | ||
236 | void get_online_cpus(void) | |
237 | { | |
238 | might_sleep(); | |
239 | if (cpu_hotplug.active_writer == current) | |
240 | return; | |
241 | cpuhp_lock_acquire_read(); | |
242 | mutex_lock(&cpu_hotplug.lock); | |
243 | atomic_inc(&cpu_hotplug.refcount); | |
244 | mutex_unlock(&cpu_hotplug.lock); | |
245 | } | |
246 | EXPORT_SYMBOL_GPL(get_online_cpus); | |
247 | ||
248 | void put_online_cpus(void) | |
249 | { | |
250 | int refcount; | |
251 | ||
252 | if (cpu_hotplug.active_writer == current) | |
253 | return; | |
254 | ||
255 | refcount = atomic_dec_return(&cpu_hotplug.refcount); | |
256 | if (WARN_ON(refcount < 0)) /* try to fix things up */ | |
257 | atomic_inc(&cpu_hotplug.refcount); | |
258 | ||
259 | if (refcount <= 0 && waitqueue_active(&cpu_hotplug.wq)) | |
260 | wake_up(&cpu_hotplug.wq); | |
261 | ||
262 | cpuhp_lock_release(); | |
263 | ||
264 | } | |
265 | EXPORT_SYMBOL_GPL(put_online_cpus); | |
266 | ||
267 | /* | |
268 | * This ensures that the hotplug operation can begin only when the | |
269 | * refcount goes to zero. | |
270 | * | |
271 | * Note that during a cpu-hotplug operation, the new readers, if any, | |
272 | * will be blocked by the cpu_hotplug.lock | |
273 | * | |
274 | * Since cpu_hotplug_begin() is always called after invoking | |
275 | * cpu_maps_update_begin(), we can be sure that only one writer is active. | |
276 | * | |
277 | * Note that theoretically, there is a possibility of a livelock: | |
278 | * - Refcount goes to zero, last reader wakes up the sleeping | |
279 | * writer. | |
280 | * - Last reader unlocks the cpu_hotplug.lock. | |
281 | * - A new reader arrives at this moment, bumps up the refcount. | |
282 | * - The writer acquires the cpu_hotplug.lock finds the refcount | |
283 | * non zero and goes to sleep again. | |
284 | * | |
285 | * However, this is very difficult to achieve in practice since | |
286 | * get_online_cpus() not an api which is called all that often. | |
287 | * | |
288 | */ | |
289 | void cpu_hotplug_begin(void) | |
290 | { | |
291 | DEFINE_WAIT(wait); | |
292 | ||
293 | cpu_hotplug.active_writer = current; | |
294 | cpuhp_lock_acquire(); | |
295 | ||
296 | for (;;) { | |
297 | mutex_lock(&cpu_hotplug.lock); | |
298 | prepare_to_wait(&cpu_hotplug.wq, &wait, TASK_UNINTERRUPTIBLE); | |
299 | if (likely(!atomic_read(&cpu_hotplug.refcount))) | |
300 | break; | |
301 | mutex_unlock(&cpu_hotplug.lock); | |
302 | schedule(); | |
303 | } | |
304 | finish_wait(&cpu_hotplug.wq, &wait); | |
305 | } | |
306 | ||
307 | void cpu_hotplug_done(void) | |
308 | { | |
309 | cpu_hotplug.active_writer = NULL; | |
310 | mutex_unlock(&cpu_hotplug.lock); | |
311 | cpuhp_lock_release(); | |
312 | } | |
313 | ||
314 | /* | |
315 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
316 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
317 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
318 | * hotplug path before performing hotplug operations. So acquiring that lock | |
319 | * guarantees mutual exclusion from any currently running hotplug operations. | |
320 | */ | |
321 | void cpu_hotplug_disable(void) | |
322 | { | |
323 | cpu_maps_update_begin(); | |
324 | cpu_hotplug_disabled++; | |
325 | cpu_maps_update_done(); | |
326 | } | |
327 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); | |
328 | ||
329 | static void __cpu_hotplug_enable(void) | |
330 | { | |
331 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) | |
332 | return; | |
333 | cpu_hotplug_disabled--; | |
334 | } | |
335 | ||
336 | void cpu_hotplug_enable(void) | |
337 | { | |
338 | cpu_maps_update_begin(); | |
339 | __cpu_hotplug_enable(); | |
340 | cpu_maps_update_done(); | |
341 | } | |
342 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); | |
343 | #endif /* CONFIG_HOTPLUG_CPU */ | |
344 | ||
345 | /* Notifier wrappers for transitioning to state machine */ | |
346 | ||
347 | static int bringup_wait_for_ap(unsigned int cpu) | |
348 | { | |
349 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
350 | ||
351 | wait_for_completion(&st->done); | |
352 | return st->result; | |
353 | } | |
354 | ||
355 | static int bringup_cpu(unsigned int cpu) | |
356 | { | |
357 | struct task_struct *idle = idle_thread_get(cpu); | |
358 | int ret; | |
359 | ||
360 | /* | |
361 | * Some architectures have to walk the irq descriptors to | |
362 | * setup the vector space for the cpu which comes online. | |
363 | * Prevent irq alloc/free across the bringup. | |
364 | */ | |
365 | irq_lock_sparse(); | |
366 | ||
367 | /* Arch-specific enabling code. */ | |
368 | ret = __cpu_up(cpu, idle); | |
369 | irq_unlock_sparse(); | |
370 | if (ret) | |
371 | return ret; | |
372 | ret = bringup_wait_for_ap(cpu); | |
373 | BUG_ON(!cpu_online(cpu)); | |
374 | return ret; | |
375 | } | |
376 | ||
377 | /* | |
378 | * Hotplug state machine related functions | |
379 | */ | |
380 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) | |
381 | { | |
382 | for (st->state++; st->state < st->target; st->state++) { | |
383 | struct cpuhp_step *step = cpuhp_get_step(st->state); | |
384 | ||
385 | if (!step->skip_onerr) | |
386 | cpuhp_invoke_callback(cpu, st->state, true, NULL); | |
387 | } | |
388 | } | |
389 | ||
390 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
391 | enum cpuhp_state target) | |
392 | { | |
393 | enum cpuhp_state prev_state = st->state; | |
394 | int ret = 0; | |
395 | ||
396 | for (; st->state > target; st->state--) { | |
397 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL); | |
398 | if (ret) { | |
399 | st->target = prev_state; | |
400 | undo_cpu_down(cpu, st); | |
401 | break; | |
402 | } | |
403 | } | |
404 | return ret; | |
405 | } | |
406 | ||
407 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) | |
408 | { | |
409 | for (st->state--; st->state > st->target; st->state--) { | |
410 | struct cpuhp_step *step = cpuhp_get_step(st->state); | |
411 | ||
412 | if (!step->skip_onerr) | |
413 | cpuhp_invoke_callback(cpu, st->state, false, NULL); | |
414 | } | |
415 | } | |
416 | ||
417 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
418 | enum cpuhp_state target) | |
419 | { | |
420 | enum cpuhp_state prev_state = st->state; | |
421 | int ret = 0; | |
422 | ||
423 | while (st->state < target) { | |
424 | st->state++; | |
425 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL); | |
426 | if (ret) { | |
427 | st->target = prev_state; | |
428 | undo_cpu_up(cpu, st); | |
429 | break; | |
430 | } | |
431 | } | |
432 | return ret; | |
433 | } | |
434 | ||
435 | /* | |
436 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
437 | */ | |
438 | static void cpuhp_create(unsigned int cpu) | |
439 | { | |
440 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
441 | ||
442 | init_completion(&st->done); | |
443 | } | |
444 | ||
445 | static int cpuhp_should_run(unsigned int cpu) | |
446 | { | |
447 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
448 | ||
449 | return st->should_run; | |
450 | } | |
451 | ||
452 | /* Execute the teardown callbacks. Used to be CPU_DOWN_PREPARE */ | |
453 | static int cpuhp_ap_offline(unsigned int cpu, struct cpuhp_cpu_state *st) | |
454 | { | |
455 | enum cpuhp_state target = max((int)st->target, CPUHP_TEARDOWN_CPU); | |
456 | ||
457 | return cpuhp_down_callbacks(cpu, st, target); | |
458 | } | |
459 | ||
460 | /* Execute the online startup callbacks. Used to be CPU_ONLINE */ | |
461 | static int cpuhp_ap_online(unsigned int cpu, struct cpuhp_cpu_state *st) | |
462 | { | |
463 | return cpuhp_up_callbacks(cpu, st, st->target); | |
464 | } | |
465 | ||
466 | /* | |
467 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
468 | * callbacks when a state gets [un]installed at runtime. | |
469 | */ | |
470 | static void cpuhp_thread_fun(unsigned int cpu) | |
471 | { | |
472 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
473 | int ret = 0; | |
474 | ||
475 | /* | |
476 | * Paired with the mb() in cpuhp_kick_ap_work and | |
477 | * cpuhp_invoke_ap_callback, so the work set is consistent visible. | |
478 | */ | |
479 | smp_mb(); | |
480 | if (!st->should_run) | |
481 | return; | |
482 | ||
483 | st->should_run = false; | |
484 | ||
485 | /* Single callback invocation for [un]install ? */ | |
486 | if (st->single) { | |
487 | if (st->cb_state < CPUHP_AP_ONLINE) { | |
488 | local_irq_disable(); | |
489 | ret = cpuhp_invoke_callback(cpu, st->cb_state, | |
490 | st->bringup, st->node); | |
491 | local_irq_enable(); | |
492 | } else { | |
493 | ret = cpuhp_invoke_callback(cpu, st->cb_state, | |
494 | st->bringup, st->node); | |
495 | } | |
496 | } else if (st->rollback) { | |
497 | BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE); | |
498 | ||
499 | undo_cpu_down(cpu, st); | |
500 | st->rollback = false; | |
501 | } else { | |
502 | /* Cannot happen .... */ | |
503 | BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE); | |
504 | ||
505 | /* Regular hotplug work */ | |
506 | if (st->state < st->target) | |
507 | ret = cpuhp_ap_online(cpu, st); | |
508 | else if (st->state > st->target) | |
509 | ret = cpuhp_ap_offline(cpu, st); | |
510 | } | |
511 | st->result = ret; | |
512 | complete(&st->done); | |
513 | } | |
514 | ||
515 | /* Invoke a single callback on a remote cpu */ | |
516 | static int | |
517 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, | |
518 | struct hlist_node *node) | |
519 | { | |
520 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
521 | ||
522 | if (!cpu_online(cpu)) | |
523 | return 0; | |
524 | ||
525 | /* | |
526 | * If we are up and running, use the hotplug thread. For early calls | |
527 | * we invoke the thread function directly. | |
528 | */ | |
529 | if (!st->thread) | |
530 | return cpuhp_invoke_callback(cpu, state, bringup, node); | |
531 | ||
532 | st->cb_state = state; | |
533 | st->single = true; | |
534 | st->bringup = bringup; | |
535 | st->node = node; | |
536 | ||
537 | /* | |
538 | * Make sure the above stores are visible before should_run becomes | |
539 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
540 | */ | |
541 | smp_mb(); | |
542 | st->should_run = true; | |
543 | wake_up_process(st->thread); | |
544 | wait_for_completion(&st->done); | |
545 | return st->result; | |
546 | } | |
547 | ||
548 | /* Regular hotplug invocation of the AP hotplug thread */ | |
549 | static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st) | |
550 | { | |
551 | st->result = 0; | |
552 | st->single = false; | |
553 | /* | |
554 | * Make sure the above stores are visible before should_run becomes | |
555 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
556 | */ | |
557 | smp_mb(); | |
558 | st->should_run = true; | |
559 | wake_up_process(st->thread); | |
560 | } | |
561 | ||
562 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
563 | { | |
564 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
565 | enum cpuhp_state state = st->state; | |
566 | ||
567 | trace_cpuhp_enter(cpu, st->target, state, cpuhp_kick_ap_work); | |
568 | __cpuhp_kick_ap_work(st); | |
569 | wait_for_completion(&st->done); | |
570 | trace_cpuhp_exit(cpu, st->state, state, st->result); | |
571 | return st->result; | |
572 | } | |
573 | ||
574 | static struct smp_hotplug_thread cpuhp_threads = { | |
575 | .store = &cpuhp_state.thread, | |
576 | .create = &cpuhp_create, | |
577 | .thread_should_run = cpuhp_should_run, | |
578 | .thread_fn = cpuhp_thread_fun, | |
579 | .thread_comm = "cpuhp/%u", | |
580 | .selfparking = true, | |
581 | }; | |
582 | ||
583 | void __init cpuhp_threads_init(void) | |
584 | { | |
585 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
586 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
587 | } | |
588 | ||
589 | #ifdef CONFIG_HOTPLUG_CPU | |
590 | /** | |
591 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
592 | * @cpu: a CPU id | |
593 | * | |
594 | * This function walks all processes, finds a valid mm struct for each one and | |
595 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
596 | * trivial, there are various non-obvious corner cases, which this function | |
597 | * tries to solve in a safe manner. | |
598 | * | |
599 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
600 | * be called only for an already offlined CPU. | |
601 | */ | |
602 | void clear_tasks_mm_cpumask(int cpu) | |
603 | { | |
604 | struct task_struct *p; | |
605 | ||
606 | /* | |
607 | * This function is called after the cpu is taken down and marked | |
608 | * offline, so its not like new tasks will ever get this cpu set in | |
609 | * their mm mask. -- Peter Zijlstra | |
610 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
611 | * full-fledged tasklist_lock. | |
612 | */ | |
613 | WARN_ON(cpu_online(cpu)); | |
614 | rcu_read_lock(); | |
615 | for_each_process(p) { | |
616 | struct task_struct *t; | |
617 | ||
618 | /* | |
619 | * Main thread might exit, but other threads may still have | |
620 | * a valid mm. Find one. | |
621 | */ | |
622 | t = find_lock_task_mm(p); | |
623 | if (!t) | |
624 | continue; | |
625 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
626 | task_unlock(t); | |
627 | } | |
628 | rcu_read_unlock(); | |
629 | } | |
630 | ||
631 | static inline void check_for_tasks(int dead_cpu) | |
632 | { | |
633 | struct task_struct *g, *p; | |
634 | ||
635 | read_lock(&tasklist_lock); | |
636 | for_each_process_thread(g, p) { | |
637 | if (!p->on_rq) | |
638 | continue; | |
639 | /* | |
640 | * We do the check with unlocked task_rq(p)->lock. | |
641 | * Order the reading to do not warn about a task, | |
642 | * which was running on this cpu in the past, and | |
643 | * it's just been woken on another cpu. | |
644 | */ | |
645 | rmb(); | |
646 | if (task_cpu(p) != dead_cpu) | |
647 | continue; | |
648 | ||
649 | pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n", | |
650 | p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags); | |
651 | } | |
652 | read_unlock(&tasklist_lock); | |
653 | } | |
654 | ||
655 | /* Take this CPU down. */ | |
656 | static int take_cpu_down(void *_param) | |
657 | { | |
658 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
659 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
660 | int err, cpu = smp_processor_id(); | |
661 | ||
662 | /* Ensure this CPU doesn't handle any more interrupts. */ | |
663 | err = __cpu_disable(); | |
664 | if (err < 0) | |
665 | return err; | |
666 | ||
667 | /* | |
668 | * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not | |
669 | * do this step again. | |
670 | */ | |
671 | WARN_ON(st->state != CPUHP_TEARDOWN_CPU); | |
672 | st->state--; | |
673 | /* Invoke the former CPU_DYING callbacks */ | |
674 | for (; st->state > target; st->state--) | |
675 | cpuhp_invoke_callback(cpu, st->state, false, NULL); | |
676 | ||
677 | /* Give up timekeeping duties */ | |
678 | tick_handover_do_timer(); | |
679 | /* Park the stopper thread */ | |
680 | stop_machine_park(cpu); | |
681 | return 0; | |
682 | } | |
683 | ||
684 | static int takedown_cpu(unsigned int cpu) | |
685 | { | |
686 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
687 | int err; | |
688 | ||
689 | /* Park the smpboot threads */ | |
690 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); | |
691 | smpboot_park_threads(cpu); | |
692 | ||
693 | /* | |
694 | * Prevent irq alloc/free while the dying cpu reorganizes the | |
695 | * interrupt affinities. | |
696 | */ | |
697 | irq_lock_sparse(); | |
698 | ||
699 | /* | |
700 | * So now all preempt/rcu users must observe !cpu_active(). | |
701 | */ | |
702 | err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu)); | |
703 | if (err) { | |
704 | /* CPU refused to die */ | |
705 | irq_unlock_sparse(); | |
706 | /* Unpark the hotplug thread so we can rollback there */ | |
707 | kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); | |
708 | return err; | |
709 | } | |
710 | BUG_ON(cpu_online(cpu)); | |
711 | ||
712 | /* | |
713 | * The CPUHP_AP_SCHED_MIGRATE_DYING callback will have removed all | |
714 | * runnable tasks from the cpu, there's only the idle task left now | |
715 | * that the migration thread is done doing the stop_machine thing. | |
716 | * | |
717 | * Wait for the stop thread to go away. | |
718 | */ | |
719 | wait_for_completion(&st->done); | |
720 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); | |
721 | ||
722 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ | |
723 | irq_unlock_sparse(); | |
724 | ||
725 | hotplug_cpu__broadcast_tick_pull(cpu); | |
726 | /* This actually kills the CPU. */ | |
727 | __cpu_die(cpu); | |
728 | ||
729 | tick_cleanup_dead_cpu(cpu); | |
730 | return 0; | |
731 | } | |
732 | ||
733 | static void cpuhp_complete_idle_dead(void *arg) | |
734 | { | |
735 | struct cpuhp_cpu_state *st = arg; | |
736 | ||
737 | complete(&st->done); | |
738 | } | |
739 | ||
740 | void cpuhp_report_idle_dead(void) | |
741 | { | |
742 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
743 | ||
744 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
745 | rcu_report_dead(smp_processor_id()); | |
746 | st->state = CPUHP_AP_IDLE_DEAD; | |
747 | /* | |
748 | * We cannot call complete after rcu_report_dead() so we delegate it | |
749 | * to an online cpu. | |
750 | */ | |
751 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
752 | cpuhp_complete_idle_dead, st, 0); | |
753 | } | |
754 | ||
755 | #else | |
756 | #define takedown_cpu NULL | |
757 | #endif | |
758 | ||
759 | #ifdef CONFIG_HOTPLUG_CPU | |
760 | ||
761 | /* Requires cpu_add_remove_lock to be held */ | |
762 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, | |
763 | enum cpuhp_state target) | |
764 | { | |
765 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
766 | int prev_state, ret = 0; | |
767 | ||
768 | if (num_online_cpus() == 1) | |
769 | return -EBUSY; | |
770 | ||
771 | if (!cpu_present(cpu)) | |
772 | return -EINVAL; | |
773 | ||
774 | cpu_hotplug_begin(); | |
775 | ||
776 | cpuhp_tasks_frozen = tasks_frozen; | |
777 | ||
778 | prev_state = st->state; | |
779 | st->target = target; | |
780 | /* | |
781 | * If the current CPU state is in the range of the AP hotplug thread, | |
782 | * then we need to kick the thread. | |
783 | */ | |
784 | if (st->state > CPUHP_TEARDOWN_CPU) { | |
785 | ret = cpuhp_kick_ap_work(cpu); | |
786 | /* | |
787 | * The AP side has done the error rollback already. Just | |
788 | * return the error code.. | |
789 | */ | |
790 | if (ret) | |
791 | goto out; | |
792 | ||
793 | /* | |
794 | * We might have stopped still in the range of the AP hotplug | |
795 | * thread. Nothing to do anymore. | |
796 | */ | |
797 | if (st->state > CPUHP_TEARDOWN_CPU) | |
798 | goto out; | |
799 | } | |
800 | /* | |
801 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need | |
802 | * to do the further cleanups. | |
803 | */ | |
804 | ret = cpuhp_down_callbacks(cpu, st, target); | |
805 | if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) { | |
806 | st->target = prev_state; | |
807 | st->rollback = true; | |
808 | cpuhp_kick_ap_work(cpu); | |
809 | } | |
810 | ||
811 | out: | |
812 | cpu_hotplug_done(); | |
813 | return ret; | |
814 | } | |
815 | ||
816 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) | |
817 | { | |
818 | int err; | |
819 | ||
820 | cpu_maps_update_begin(); | |
821 | ||
822 | if (cpu_hotplug_disabled) { | |
823 | err = -EBUSY; | |
824 | goto out; | |
825 | } | |
826 | ||
827 | err = _cpu_down(cpu, 0, target); | |
828 | ||
829 | out: | |
830 | cpu_maps_update_done(); | |
831 | return err; | |
832 | } | |
833 | int cpu_down(unsigned int cpu) | |
834 | { | |
835 | return do_cpu_down(cpu, CPUHP_OFFLINE); | |
836 | } | |
837 | EXPORT_SYMBOL(cpu_down); | |
838 | #endif /*CONFIG_HOTPLUG_CPU*/ | |
839 | ||
840 | /** | |
841 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU | |
842 | * @cpu: cpu that just started | |
843 | * | |
844 | * It must be called by the arch code on the new cpu, before the new cpu | |
845 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
846 | */ | |
847 | void notify_cpu_starting(unsigned int cpu) | |
848 | { | |
849 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
850 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
851 | ||
852 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ | |
853 | while (st->state < target) { | |
854 | st->state++; | |
855 | cpuhp_invoke_callback(cpu, st->state, true, NULL); | |
856 | } | |
857 | } | |
858 | ||
859 | /* | |
860 | * Called from the idle task. We need to set active here, so we can kick off | |
861 | * the stopper thread and unpark the smpboot threads. If the target state is | |
862 | * beyond CPUHP_AP_ONLINE_IDLE we kick cpuhp thread and let it bring up the | |
863 | * cpu further. | |
864 | */ | |
865 | void cpuhp_online_idle(enum cpuhp_state state) | |
866 | { | |
867 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
868 | unsigned int cpu = smp_processor_id(); | |
869 | ||
870 | /* Happens for the boot cpu */ | |
871 | if (state != CPUHP_AP_ONLINE_IDLE) | |
872 | return; | |
873 | ||
874 | st->state = CPUHP_AP_ONLINE_IDLE; | |
875 | ||
876 | /* Unpark the stopper thread and the hotplug thread of this cpu */ | |
877 | stop_machine_unpark(cpu); | |
878 | kthread_unpark(st->thread); | |
879 | ||
880 | /* Should we go further up ? */ | |
881 | if (st->target > CPUHP_AP_ONLINE_IDLE) | |
882 | __cpuhp_kick_ap_work(st); | |
883 | else | |
884 | complete(&st->done); | |
885 | } | |
886 | ||
887 | /* Requires cpu_add_remove_lock to be held */ | |
888 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) | |
889 | { | |
890 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
891 | struct task_struct *idle; | |
892 | int ret = 0; | |
893 | ||
894 | cpu_hotplug_begin(); | |
895 | ||
896 | if (!cpu_present(cpu)) { | |
897 | ret = -EINVAL; | |
898 | goto out; | |
899 | } | |
900 | ||
901 | /* | |
902 | * The caller of do_cpu_up might have raced with another | |
903 | * caller. Ignore it for now. | |
904 | */ | |
905 | if (st->state >= target) | |
906 | goto out; | |
907 | ||
908 | if (st->state == CPUHP_OFFLINE) { | |
909 | /* Let it fail before we try to bring the cpu up */ | |
910 | idle = idle_thread_get(cpu); | |
911 | if (IS_ERR(idle)) { | |
912 | ret = PTR_ERR(idle); | |
913 | goto out; | |
914 | } | |
915 | } | |
916 | ||
917 | cpuhp_tasks_frozen = tasks_frozen; | |
918 | ||
919 | st->target = target; | |
920 | /* | |
921 | * If the current CPU state is in the range of the AP hotplug thread, | |
922 | * then we need to kick the thread once more. | |
923 | */ | |
924 | if (st->state > CPUHP_BRINGUP_CPU) { | |
925 | ret = cpuhp_kick_ap_work(cpu); | |
926 | /* | |
927 | * The AP side has done the error rollback already. Just | |
928 | * return the error code.. | |
929 | */ | |
930 | if (ret) | |
931 | goto out; | |
932 | } | |
933 | ||
934 | /* | |
935 | * Try to reach the target state. We max out on the BP at | |
936 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is | |
937 | * responsible for bringing it up to the target state. | |
938 | */ | |
939 | target = min((int)target, CPUHP_BRINGUP_CPU); | |
940 | ret = cpuhp_up_callbacks(cpu, st, target); | |
941 | out: | |
942 | cpu_hotplug_done(); | |
943 | return ret; | |
944 | } | |
945 | ||
946 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) | |
947 | { | |
948 | int err = 0; | |
949 | ||
950 | if (!cpu_possible(cpu)) { | |
951 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", | |
952 | cpu); | |
953 | #if defined(CONFIG_IA64) | |
954 | pr_err("please check additional_cpus= boot parameter\n"); | |
955 | #endif | |
956 | return -EINVAL; | |
957 | } | |
958 | ||
959 | err = try_online_node(cpu_to_node(cpu)); | |
960 | if (err) | |
961 | return err; | |
962 | ||
963 | cpu_maps_update_begin(); | |
964 | ||
965 | if (cpu_hotplug_disabled) { | |
966 | err = -EBUSY; | |
967 | goto out; | |
968 | } | |
969 | ||
970 | err = _cpu_up(cpu, 0, target); | |
971 | out: | |
972 | cpu_maps_update_done(); | |
973 | return err; | |
974 | } | |
975 | ||
976 | int cpu_up(unsigned int cpu) | |
977 | { | |
978 | return do_cpu_up(cpu, CPUHP_ONLINE); | |
979 | } | |
980 | EXPORT_SYMBOL_GPL(cpu_up); | |
981 | ||
982 | #ifdef CONFIG_PM_SLEEP_SMP | |
983 | static cpumask_var_t frozen_cpus; | |
984 | ||
985 | int freeze_secondary_cpus(int primary) | |
986 | { | |
987 | int cpu, error = 0; | |
988 | ||
989 | cpu_maps_update_begin(); | |
990 | if (!cpu_online(primary)) | |
991 | primary = cpumask_first(cpu_online_mask); | |
992 | /* | |
993 | * We take down all of the non-boot CPUs in one shot to avoid races | |
994 | * with the userspace trying to use the CPU hotplug at the same time | |
995 | */ | |
996 | cpumask_clear(frozen_cpus); | |
997 | ||
998 | pr_info("Disabling non-boot CPUs ...\n"); | |
999 | for_each_online_cpu(cpu) { | |
1000 | if (cpu == primary) | |
1001 | continue; | |
1002 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); | |
1003 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); | |
1004 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); | |
1005 | if (!error) | |
1006 | cpumask_set_cpu(cpu, frozen_cpus); | |
1007 | else { | |
1008 | pr_err("Error taking CPU%d down: %d\n", cpu, error); | |
1009 | break; | |
1010 | } | |
1011 | } | |
1012 | ||
1013 | if (!error) | |
1014 | BUG_ON(num_online_cpus() > 1); | |
1015 | else | |
1016 | pr_err("Non-boot CPUs are not disabled\n"); | |
1017 | ||
1018 | /* | |
1019 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
1020 | * this even in case of failure as all disable_nonboot_cpus() users are | |
1021 | * supposed to do enable_nonboot_cpus() on the failure path. | |
1022 | */ | |
1023 | cpu_hotplug_disabled++; | |
1024 | ||
1025 | cpu_maps_update_done(); | |
1026 | return error; | |
1027 | } | |
1028 | ||
1029 | void __weak arch_enable_nonboot_cpus_begin(void) | |
1030 | { | |
1031 | } | |
1032 | ||
1033 | void __weak arch_enable_nonboot_cpus_end(void) | |
1034 | { | |
1035 | } | |
1036 | ||
1037 | void enable_nonboot_cpus(void) | |
1038 | { | |
1039 | int cpu, error; | |
1040 | ||
1041 | /* Allow everyone to use the CPU hotplug again */ | |
1042 | cpu_maps_update_begin(); | |
1043 | __cpu_hotplug_enable(); | |
1044 | if (cpumask_empty(frozen_cpus)) | |
1045 | goto out; | |
1046 | ||
1047 | pr_info("Enabling non-boot CPUs ...\n"); | |
1048 | ||
1049 | arch_enable_nonboot_cpus_begin(); | |
1050 | ||
1051 | for_each_cpu(cpu, frozen_cpus) { | |
1052 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); | |
1053 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); | |
1054 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); | |
1055 | if (!error) { | |
1056 | pr_info("CPU%d is up\n", cpu); | |
1057 | continue; | |
1058 | } | |
1059 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); | |
1060 | } | |
1061 | ||
1062 | arch_enable_nonboot_cpus_end(); | |
1063 | ||
1064 | cpumask_clear(frozen_cpus); | |
1065 | out: | |
1066 | cpu_maps_update_done(); | |
1067 | } | |
1068 | ||
1069 | static int __init alloc_frozen_cpus(void) | |
1070 | { | |
1071 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1072 | return -ENOMEM; | |
1073 | return 0; | |
1074 | } | |
1075 | core_initcall(alloc_frozen_cpus); | |
1076 | ||
1077 | /* | |
1078 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1079 | * ensure that the state of the system with respect to the tasks being frozen | |
1080 | * or not, as reported by the notification, remains unchanged *throughout the | |
1081 | * duration* of the execution of the callbacks. | |
1082 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1083 | * | |
1084 | * This synchronization is implemented by mutually excluding regular CPU | |
1085 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1086 | * Hibernate notifications. | |
1087 | */ | |
1088 | static int | |
1089 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1090 | unsigned long action, void *ptr) | |
1091 | { | |
1092 | switch (action) { | |
1093 | ||
1094 | case PM_SUSPEND_PREPARE: | |
1095 | case PM_HIBERNATION_PREPARE: | |
1096 | cpu_hotplug_disable(); | |
1097 | break; | |
1098 | ||
1099 | case PM_POST_SUSPEND: | |
1100 | case PM_POST_HIBERNATION: | |
1101 | cpu_hotplug_enable(); | |
1102 | break; | |
1103 | ||
1104 | default: | |
1105 | return NOTIFY_DONE; | |
1106 | } | |
1107 | ||
1108 | return NOTIFY_OK; | |
1109 | } | |
1110 | ||
1111 | ||
1112 | static int __init cpu_hotplug_pm_sync_init(void) | |
1113 | { | |
1114 | /* | |
1115 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1116 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1117 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1118 | */ | |
1119 | pm_notifier(cpu_hotplug_pm_callback, 0); | |
1120 | return 0; | |
1121 | } | |
1122 | core_initcall(cpu_hotplug_pm_sync_init); | |
1123 | ||
1124 | #endif /* CONFIG_PM_SLEEP_SMP */ | |
1125 | ||
1126 | #endif /* CONFIG_SMP */ | |
1127 | ||
1128 | /* Boot processor state steps */ | |
1129 | static struct cpuhp_step cpuhp_bp_states[] = { | |
1130 | [CPUHP_OFFLINE] = { | |
1131 | .name = "offline", | |
1132 | .startup.single = NULL, | |
1133 | .teardown.single = NULL, | |
1134 | }, | |
1135 | #ifdef CONFIG_SMP | |
1136 | [CPUHP_CREATE_THREADS]= { | |
1137 | .name = "threads:prepare", | |
1138 | .startup.single = smpboot_create_threads, | |
1139 | .teardown.single = NULL, | |
1140 | .cant_stop = true, | |
1141 | }, | |
1142 | [CPUHP_PERF_PREPARE] = { | |
1143 | .name = "perf:prepare", | |
1144 | .startup.single = perf_event_init_cpu, | |
1145 | .teardown.single = perf_event_exit_cpu, | |
1146 | }, | |
1147 | [CPUHP_WORKQUEUE_PREP] = { | |
1148 | .name = "workqueue:prepare", | |
1149 | .startup.single = workqueue_prepare_cpu, | |
1150 | .teardown.single = NULL, | |
1151 | }, | |
1152 | [CPUHP_HRTIMERS_PREPARE] = { | |
1153 | .name = "hrtimers:prepare", | |
1154 | .startup.single = hrtimers_prepare_cpu, | |
1155 | .teardown.single = hrtimers_dead_cpu, | |
1156 | }, | |
1157 | [CPUHP_SMPCFD_PREPARE] = { | |
1158 | .name = "smpcfd:prepare", | |
1159 | .startup.single = smpcfd_prepare_cpu, | |
1160 | .teardown.single = smpcfd_dead_cpu, | |
1161 | }, | |
1162 | [CPUHP_RELAY_PREPARE] = { | |
1163 | .name = "relay:prepare", | |
1164 | .startup.single = relay_prepare_cpu, | |
1165 | .teardown.single = NULL, | |
1166 | }, | |
1167 | [CPUHP_SLAB_PREPARE] = { | |
1168 | .name = "slab:prepare", | |
1169 | .startup.single = slab_prepare_cpu, | |
1170 | .teardown.single = slab_dead_cpu, | |
1171 | }, | |
1172 | [CPUHP_RCUTREE_PREP] = { | |
1173 | .name = "RCU/tree:prepare", | |
1174 | .startup.single = rcutree_prepare_cpu, | |
1175 | .teardown.single = rcutree_dead_cpu, | |
1176 | }, | |
1177 | /* | |
1178 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1179 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1180 | * otherwise a RCU stall occurs. | |
1181 | */ | |
1182 | [CPUHP_TIMERS_DEAD] = { | |
1183 | .name = "timers:dead", | |
1184 | .startup.single = NULL, | |
1185 | .teardown.single = timers_dead_cpu, | |
1186 | }, | |
1187 | /* Kicks the plugged cpu into life */ | |
1188 | [CPUHP_BRINGUP_CPU] = { | |
1189 | .name = "cpu:bringup", | |
1190 | .startup.single = bringup_cpu, | |
1191 | .teardown.single = NULL, | |
1192 | .cant_stop = true, | |
1193 | }, | |
1194 | [CPUHP_AP_SMPCFD_DYING] = { | |
1195 | .name = "smpcfd:dying", | |
1196 | .startup.single = NULL, | |
1197 | .teardown.single = smpcfd_dying_cpu, | |
1198 | }, | |
1199 | /* | |
1200 | * Handled on controll processor until the plugged processor manages | |
1201 | * this itself. | |
1202 | */ | |
1203 | [CPUHP_TEARDOWN_CPU] = { | |
1204 | .name = "cpu:teardown", | |
1205 | .startup.single = NULL, | |
1206 | .teardown.single = takedown_cpu, | |
1207 | .cant_stop = true, | |
1208 | }, | |
1209 | #else | |
1210 | [CPUHP_BRINGUP_CPU] = { }, | |
1211 | #endif | |
1212 | }; | |
1213 | ||
1214 | /* Application processor state steps */ | |
1215 | static struct cpuhp_step cpuhp_ap_states[] = { | |
1216 | #ifdef CONFIG_SMP | |
1217 | /* Final state before CPU kills itself */ | |
1218 | [CPUHP_AP_IDLE_DEAD] = { | |
1219 | .name = "idle:dead", | |
1220 | }, | |
1221 | /* | |
1222 | * Last state before CPU enters the idle loop to die. Transient state | |
1223 | * for synchronization. | |
1224 | */ | |
1225 | [CPUHP_AP_OFFLINE] = { | |
1226 | .name = "ap:offline", | |
1227 | .cant_stop = true, | |
1228 | }, | |
1229 | /* First state is scheduler control. Interrupts are disabled */ | |
1230 | [CPUHP_AP_SCHED_STARTING] = { | |
1231 | .name = "sched:starting", | |
1232 | .startup.single = sched_cpu_starting, | |
1233 | .teardown.single = sched_cpu_dying, | |
1234 | }, | |
1235 | [CPUHP_AP_RCUTREE_DYING] = { | |
1236 | .name = "RCU/tree:dying", | |
1237 | .startup.single = NULL, | |
1238 | .teardown.single = rcutree_dying_cpu, | |
1239 | }, | |
1240 | /* Entry state on starting. Interrupts enabled from here on. Transient | |
1241 | * state for synchronsization */ | |
1242 | [CPUHP_AP_ONLINE] = { | |
1243 | .name = "ap:online", | |
1244 | }, | |
1245 | /* Handle smpboot threads park/unpark */ | |
1246 | [CPUHP_AP_SMPBOOT_THREADS] = { | |
1247 | .name = "smpboot/threads:online", | |
1248 | .startup.single = smpboot_unpark_threads, | |
1249 | .teardown.single = NULL, | |
1250 | }, | |
1251 | [CPUHP_AP_PERF_ONLINE] = { | |
1252 | .name = "perf:online", | |
1253 | .startup.single = perf_event_init_cpu, | |
1254 | .teardown.single = perf_event_exit_cpu, | |
1255 | }, | |
1256 | [CPUHP_AP_WORKQUEUE_ONLINE] = { | |
1257 | .name = "workqueue:online", | |
1258 | .startup.single = workqueue_online_cpu, | |
1259 | .teardown.single = workqueue_offline_cpu, | |
1260 | }, | |
1261 | [CPUHP_AP_RCUTREE_ONLINE] = { | |
1262 | .name = "RCU/tree:online", | |
1263 | .startup.single = rcutree_online_cpu, | |
1264 | .teardown.single = rcutree_offline_cpu, | |
1265 | }, | |
1266 | #endif | |
1267 | /* | |
1268 | * The dynamically registered state space is here | |
1269 | */ | |
1270 | ||
1271 | #ifdef CONFIG_SMP | |
1272 | /* Last state is scheduler control setting the cpu active */ | |
1273 | [CPUHP_AP_ACTIVE] = { | |
1274 | .name = "sched:active", | |
1275 | .startup.single = sched_cpu_activate, | |
1276 | .teardown.single = sched_cpu_deactivate, | |
1277 | }, | |
1278 | #endif | |
1279 | ||
1280 | /* CPU is fully up and running. */ | |
1281 | [CPUHP_ONLINE] = { | |
1282 | .name = "online", | |
1283 | .startup.single = NULL, | |
1284 | .teardown.single = NULL, | |
1285 | }, | |
1286 | }; | |
1287 | ||
1288 | /* Sanity check for callbacks */ | |
1289 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1290 | { | |
1291 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1292 | return -EINVAL; | |
1293 | return 0; | |
1294 | } | |
1295 | ||
1296 | /* | |
1297 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1298 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1299 | * by having no name assigned. | |
1300 | */ | |
1301 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1302 | { | |
1303 | enum cpuhp_state i, end; | |
1304 | struct cpuhp_step *step; | |
1305 | ||
1306 | switch (state) { | |
1307 | case CPUHP_AP_ONLINE_DYN: | |
1308 | step = cpuhp_ap_states + CPUHP_AP_ONLINE_DYN; | |
1309 | end = CPUHP_AP_ONLINE_DYN_END; | |
1310 | break; | |
1311 | case CPUHP_BP_PREPARE_DYN: | |
1312 | step = cpuhp_bp_states + CPUHP_BP_PREPARE_DYN; | |
1313 | end = CPUHP_BP_PREPARE_DYN_END; | |
1314 | break; | |
1315 | default: | |
1316 | return -EINVAL; | |
1317 | } | |
1318 | ||
1319 | for (i = state; i <= end; i++, step++) { | |
1320 | if (!step->name) | |
1321 | return i; | |
1322 | } | |
1323 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1324 | return -ENOSPC; | |
1325 | } | |
1326 | ||
1327 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1328 | int (*startup)(unsigned int cpu), | |
1329 | int (*teardown)(unsigned int cpu), | |
1330 | bool multi_instance) | |
1331 | { | |
1332 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1333 | struct cpuhp_step *sp; | |
1334 | int ret = 0; | |
1335 | ||
1336 | mutex_lock(&cpuhp_state_mutex); | |
1337 | ||
1338 | if (state == CPUHP_AP_ONLINE_DYN || state == CPUHP_BP_PREPARE_DYN) { | |
1339 | ret = cpuhp_reserve_state(state); | |
1340 | if (ret < 0) | |
1341 | goto out; | |
1342 | state = ret; | |
1343 | } | |
1344 | sp = cpuhp_get_step(state); | |
1345 | if (name && sp->name) { | |
1346 | ret = -EBUSY; | |
1347 | goto out; | |
1348 | } | |
1349 | sp->startup.single = startup; | |
1350 | sp->teardown.single = teardown; | |
1351 | sp->name = name; | |
1352 | sp->multi_instance = multi_instance; | |
1353 | INIT_HLIST_HEAD(&sp->list); | |
1354 | out: | |
1355 | mutex_unlock(&cpuhp_state_mutex); | |
1356 | return ret; | |
1357 | } | |
1358 | ||
1359 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1360 | { | |
1361 | return cpuhp_get_step(state)->teardown.single; | |
1362 | } | |
1363 | ||
1364 | /* | |
1365 | * Call the startup/teardown function for a step either on the AP or | |
1366 | * on the current CPU. | |
1367 | */ | |
1368 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, | |
1369 | struct hlist_node *node) | |
1370 | { | |
1371 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1372 | int ret; | |
1373 | ||
1374 | if ((bringup && !sp->startup.single) || | |
1375 | (!bringup && !sp->teardown.single)) | |
1376 | return 0; | |
1377 | /* | |
1378 | * The non AP bound callbacks can fail on bringup. On teardown | |
1379 | * e.g. module removal we crash for now. | |
1380 | */ | |
1381 | #ifdef CONFIG_SMP | |
1382 | if (cpuhp_is_ap_state(state)) | |
1383 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); | |
1384 | else | |
1385 | ret = cpuhp_invoke_callback(cpu, state, bringup, node); | |
1386 | #else | |
1387 | ret = cpuhp_invoke_callback(cpu, state, bringup, node); | |
1388 | #endif | |
1389 | BUG_ON(ret && !bringup); | |
1390 | return ret; | |
1391 | } | |
1392 | ||
1393 | /* | |
1394 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1395 | * | |
1396 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1397 | */ | |
1398 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
1399 | struct hlist_node *node) | |
1400 | { | |
1401 | int cpu; | |
1402 | ||
1403 | /* Roll back the already executed steps on the other cpus */ | |
1404 | for_each_present_cpu(cpu) { | |
1405 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1406 | int cpustate = st->state; | |
1407 | ||
1408 | if (cpu >= failedcpu) | |
1409 | break; | |
1410 | ||
1411 | /* Did we invoke the startup call on that cpu ? */ | |
1412 | if (cpustate >= state) | |
1413 | cpuhp_issue_call(cpu, state, false, node); | |
1414 | } | |
1415 | } | |
1416 | ||
1417 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
1418 | bool invoke) | |
1419 | { | |
1420 | struct cpuhp_step *sp; | |
1421 | int cpu; | |
1422 | int ret; | |
1423 | ||
1424 | sp = cpuhp_get_step(state); | |
1425 | if (sp->multi_instance == false) | |
1426 | return -EINVAL; | |
1427 | ||
1428 | get_online_cpus(); | |
1429 | ||
1430 | if (!invoke || !sp->startup.multi) | |
1431 | goto add_node; | |
1432 | ||
1433 | /* | |
1434 | * Try to call the startup callback for each present cpu | |
1435 | * depending on the hotplug state of the cpu. | |
1436 | */ | |
1437 | for_each_present_cpu(cpu) { | |
1438 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1439 | int cpustate = st->state; | |
1440 | ||
1441 | if (cpustate < state) | |
1442 | continue; | |
1443 | ||
1444 | ret = cpuhp_issue_call(cpu, state, true, node); | |
1445 | if (ret) { | |
1446 | if (sp->teardown.multi) | |
1447 | cpuhp_rollback_install(cpu, state, node); | |
1448 | goto err; | |
1449 | } | |
1450 | } | |
1451 | add_node: | |
1452 | ret = 0; | |
1453 | mutex_lock(&cpuhp_state_mutex); | |
1454 | hlist_add_head(node, &sp->list); | |
1455 | mutex_unlock(&cpuhp_state_mutex); | |
1456 | ||
1457 | err: | |
1458 | put_online_cpus(); | |
1459 | return ret; | |
1460 | } | |
1461 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
1462 | ||
1463 | /** | |
1464 | * __cpuhp_setup_state - Setup the callbacks for an hotplug machine state | |
1465 | * @state: The state to setup | |
1466 | * @invoke: If true, the startup function is invoked for cpus where | |
1467 | * cpu state >= @state | |
1468 | * @startup: startup callback function | |
1469 | * @teardown: teardown callback function | |
1470 | * @multi_instance: State is set up for multiple instances which get | |
1471 | * added afterwards. | |
1472 | * | |
1473 | * Returns: | |
1474 | * On success: | |
1475 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN | |
1476 | * 0 for all other states | |
1477 | * On failure: proper (negative) error code | |
1478 | */ | |
1479 | int __cpuhp_setup_state(enum cpuhp_state state, | |
1480 | const char *name, bool invoke, | |
1481 | int (*startup)(unsigned int cpu), | |
1482 | int (*teardown)(unsigned int cpu), | |
1483 | bool multi_instance) | |
1484 | { | |
1485 | int cpu, ret = 0; | |
1486 | bool dynstate; | |
1487 | ||
1488 | if (cpuhp_cb_check(state) || !name) | |
1489 | return -EINVAL; | |
1490 | ||
1491 | get_online_cpus(); | |
1492 | ||
1493 | ret = cpuhp_store_callbacks(state, name, startup, teardown, | |
1494 | multi_instance); | |
1495 | ||
1496 | dynstate = state == CPUHP_AP_ONLINE_DYN; | |
1497 | if (ret > 0 && dynstate) { | |
1498 | state = ret; | |
1499 | ret = 0; | |
1500 | } | |
1501 | ||
1502 | if (ret || !invoke || !startup) | |
1503 | goto out; | |
1504 | ||
1505 | /* | |
1506 | * Try to call the startup callback for each present cpu | |
1507 | * depending on the hotplug state of the cpu. | |
1508 | */ | |
1509 | for_each_present_cpu(cpu) { | |
1510 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1511 | int cpustate = st->state; | |
1512 | ||
1513 | if (cpustate < state) | |
1514 | continue; | |
1515 | ||
1516 | ret = cpuhp_issue_call(cpu, state, true, NULL); | |
1517 | if (ret) { | |
1518 | if (teardown) | |
1519 | cpuhp_rollback_install(cpu, state, NULL); | |
1520 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
1521 | goto out; | |
1522 | } | |
1523 | } | |
1524 | out: | |
1525 | put_online_cpus(); | |
1526 | /* | |
1527 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
1528 | * dynamically allocated state in case of success. | |
1529 | */ | |
1530 | if (!ret && dynstate) | |
1531 | return state; | |
1532 | return ret; | |
1533 | } | |
1534 | EXPORT_SYMBOL(__cpuhp_setup_state); | |
1535 | ||
1536 | int __cpuhp_state_remove_instance(enum cpuhp_state state, | |
1537 | struct hlist_node *node, bool invoke) | |
1538 | { | |
1539 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1540 | int cpu; | |
1541 | ||
1542 | BUG_ON(cpuhp_cb_check(state)); | |
1543 | ||
1544 | if (!sp->multi_instance) | |
1545 | return -EINVAL; | |
1546 | ||
1547 | get_online_cpus(); | |
1548 | if (!invoke || !cpuhp_get_teardown_cb(state)) | |
1549 | goto remove; | |
1550 | /* | |
1551 | * Call the teardown callback for each present cpu depending | |
1552 | * on the hotplug state of the cpu. This function is not | |
1553 | * allowed to fail currently! | |
1554 | */ | |
1555 | for_each_present_cpu(cpu) { | |
1556 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1557 | int cpustate = st->state; | |
1558 | ||
1559 | if (cpustate >= state) | |
1560 | cpuhp_issue_call(cpu, state, false, node); | |
1561 | } | |
1562 | ||
1563 | remove: | |
1564 | mutex_lock(&cpuhp_state_mutex); | |
1565 | hlist_del(node); | |
1566 | mutex_unlock(&cpuhp_state_mutex); | |
1567 | put_online_cpus(); | |
1568 | ||
1569 | return 0; | |
1570 | } | |
1571 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
1572 | /** | |
1573 | * __cpuhp_remove_state - Remove the callbacks for an hotplug machine state | |
1574 | * @state: The state to remove | |
1575 | * @invoke: If true, the teardown function is invoked for cpus where | |
1576 | * cpu state >= @state | |
1577 | * | |
1578 | * The teardown callback is currently not allowed to fail. Think | |
1579 | * about module removal! | |
1580 | */ | |
1581 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
1582 | { | |
1583 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1584 | int cpu; | |
1585 | ||
1586 | BUG_ON(cpuhp_cb_check(state)); | |
1587 | ||
1588 | get_online_cpus(); | |
1589 | ||
1590 | if (sp->multi_instance) { | |
1591 | WARN(!hlist_empty(&sp->list), | |
1592 | "Error: Removing state %d which has instances left.\n", | |
1593 | state); | |
1594 | goto remove; | |
1595 | } | |
1596 | ||
1597 | if (!invoke || !cpuhp_get_teardown_cb(state)) | |
1598 | goto remove; | |
1599 | ||
1600 | /* | |
1601 | * Call the teardown callback for each present cpu depending | |
1602 | * on the hotplug state of the cpu. This function is not | |
1603 | * allowed to fail currently! | |
1604 | */ | |
1605 | for_each_present_cpu(cpu) { | |
1606 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1607 | int cpustate = st->state; | |
1608 | ||
1609 | if (cpustate >= state) | |
1610 | cpuhp_issue_call(cpu, state, false, NULL); | |
1611 | } | |
1612 | remove: | |
1613 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
1614 | put_online_cpus(); | |
1615 | } | |
1616 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
1617 | ||
1618 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) | |
1619 | static ssize_t show_cpuhp_state(struct device *dev, | |
1620 | struct device_attribute *attr, char *buf) | |
1621 | { | |
1622 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1623 | ||
1624 | return sprintf(buf, "%d\n", st->state); | |
1625 | } | |
1626 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
1627 | ||
1628 | static ssize_t write_cpuhp_target(struct device *dev, | |
1629 | struct device_attribute *attr, | |
1630 | const char *buf, size_t count) | |
1631 | { | |
1632 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1633 | struct cpuhp_step *sp; | |
1634 | int target, ret; | |
1635 | ||
1636 | ret = kstrtoint(buf, 10, &target); | |
1637 | if (ret) | |
1638 | return ret; | |
1639 | ||
1640 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
1641 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
1642 | return -EINVAL; | |
1643 | #else | |
1644 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
1645 | return -EINVAL; | |
1646 | #endif | |
1647 | ||
1648 | ret = lock_device_hotplug_sysfs(); | |
1649 | if (ret) | |
1650 | return ret; | |
1651 | ||
1652 | mutex_lock(&cpuhp_state_mutex); | |
1653 | sp = cpuhp_get_step(target); | |
1654 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
1655 | mutex_unlock(&cpuhp_state_mutex); | |
1656 | if (ret) | |
1657 | return ret; | |
1658 | ||
1659 | if (st->state < target) | |
1660 | ret = do_cpu_up(dev->id, target); | |
1661 | else | |
1662 | ret = do_cpu_down(dev->id, target); | |
1663 | ||
1664 | unlock_device_hotplug(); | |
1665 | return ret ? ret : count; | |
1666 | } | |
1667 | ||
1668 | static ssize_t show_cpuhp_target(struct device *dev, | |
1669 | struct device_attribute *attr, char *buf) | |
1670 | { | |
1671 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1672 | ||
1673 | return sprintf(buf, "%d\n", st->target); | |
1674 | } | |
1675 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); | |
1676 | ||
1677 | static struct attribute *cpuhp_cpu_attrs[] = { | |
1678 | &dev_attr_state.attr, | |
1679 | &dev_attr_target.attr, | |
1680 | NULL | |
1681 | }; | |
1682 | ||
1683 | static struct attribute_group cpuhp_cpu_attr_group = { | |
1684 | .attrs = cpuhp_cpu_attrs, | |
1685 | .name = "hotplug", | |
1686 | NULL | |
1687 | }; | |
1688 | ||
1689 | static ssize_t show_cpuhp_states(struct device *dev, | |
1690 | struct device_attribute *attr, char *buf) | |
1691 | { | |
1692 | ssize_t cur, res = 0; | |
1693 | int i; | |
1694 | ||
1695 | mutex_lock(&cpuhp_state_mutex); | |
1696 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { | |
1697 | struct cpuhp_step *sp = cpuhp_get_step(i); | |
1698 | ||
1699 | if (sp->name) { | |
1700 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
1701 | buf += cur; | |
1702 | res += cur; | |
1703 | } | |
1704 | } | |
1705 | mutex_unlock(&cpuhp_state_mutex); | |
1706 | return res; | |
1707 | } | |
1708 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
1709 | ||
1710 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
1711 | &dev_attr_states.attr, | |
1712 | NULL | |
1713 | }; | |
1714 | ||
1715 | static struct attribute_group cpuhp_cpu_root_attr_group = { | |
1716 | .attrs = cpuhp_cpu_root_attrs, | |
1717 | .name = "hotplug", | |
1718 | NULL | |
1719 | }; | |
1720 | ||
1721 | static int __init cpuhp_sysfs_init(void) | |
1722 | { | |
1723 | int cpu, ret; | |
1724 | ||
1725 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, | |
1726 | &cpuhp_cpu_root_attr_group); | |
1727 | if (ret) | |
1728 | return ret; | |
1729 | ||
1730 | for_each_possible_cpu(cpu) { | |
1731 | struct device *dev = get_cpu_device(cpu); | |
1732 | ||
1733 | if (!dev) | |
1734 | continue; | |
1735 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
1736 | if (ret) | |
1737 | return ret; | |
1738 | } | |
1739 | return 0; | |
1740 | } | |
1741 | device_initcall(cpuhp_sysfs_init); | |
1742 | #endif | |
1743 | ||
1744 | /* | |
1745 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
1746 | * represents all NR_CPUS bits binary values of 1<<nr. | |
1747 | * | |
1748 | * It is used by cpumask_of() to get a constant address to a CPU | |
1749 | * mask value that has a single bit set only. | |
1750 | */ | |
1751 | ||
1752 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ | |
1753 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) | |
1754 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) | |
1755 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
1756 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
1757 | ||
1758 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { | |
1759 | ||
1760 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
1761 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
1762 | #if BITS_PER_LONG > 32 | |
1763 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
1764 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
1765 | #endif | |
1766 | }; | |
1767 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); | |
1768 | ||
1769 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
1770 | EXPORT_SYMBOL(cpu_all_bits); | |
1771 | ||
1772 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
1773 | struct cpumask __cpu_possible_mask __read_mostly | |
1774 | = {CPU_BITS_ALL}; | |
1775 | #else | |
1776 | struct cpumask __cpu_possible_mask __read_mostly; | |
1777 | #endif | |
1778 | EXPORT_SYMBOL(__cpu_possible_mask); | |
1779 | ||
1780 | struct cpumask __cpu_online_mask __read_mostly; | |
1781 | EXPORT_SYMBOL(__cpu_online_mask); | |
1782 | ||
1783 | struct cpumask __cpu_present_mask __read_mostly; | |
1784 | EXPORT_SYMBOL(__cpu_present_mask); | |
1785 | ||
1786 | struct cpumask __cpu_active_mask __read_mostly; | |
1787 | EXPORT_SYMBOL(__cpu_active_mask); | |
1788 | ||
1789 | void init_cpu_present(const struct cpumask *src) | |
1790 | { | |
1791 | cpumask_copy(&__cpu_present_mask, src); | |
1792 | } | |
1793 | ||
1794 | void init_cpu_possible(const struct cpumask *src) | |
1795 | { | |
1796 | cpumask_copy(&__cpu_possible_mask, src); | |
1797 | } | |
1798 | ||
1799 | void init_cpu_online(const struct cpumask *src) | |
1800 | { | |
1801 | cpumask_copy(&__cpu_online_mask, src); | |
1802 | } | |
1803 | ||
1804 | /* | |
1805 | * Activate the first processor. | |
1806 | */ | |
1807 | void __init boot_cpu_init(void) | |
1808 | { | |
1809 | int cpu = smp_processor_id(); | |
1810 | ||
1811 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
1812 | set_cpu_online(cpu, true); | |
1813 | set_cpu_active(cpu, true); | |
1814 | set_cpu_present(cpu, true); | |
1815 | set_cpu_possible(cpu, true); | |
1816 | } | |
1817 | ||
1818 | /* | |
1819 | * Must be called _AFTER_ setting up the per_cpu areas | |
1820 | */ | |
1821 | void __init boot_cpu_state_init(void) | |
1822 | { | |
1823 | per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE; | |
1824 | } |