]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
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> | |
cb79295e AV |
13 | #include <linux/oom.h> |
14 | #include <linux/rcupdate.h> | |
9984de1a | 15 | #include <linux/export.h> |
e4cc2f87 | 16 | #include <linux/bug.h> |
1da177e4 LT |
17 | #include <linux/kthread.h> |
18 | #include <linux/stop_machine.h> | |
81615b62 | 19 | #include <linux/mutex.h> |
5a0e3ad6 | 20 | #include <linux/gfp.h> |
79cfbdfa | 21 | #include <linux/suspend.h> |
a19423b9 | 22 | #include <linux/lockdep.h> |
345527b1 | 23 | #include <linux/tick.h> |
a8994181 | 24 | #include <linux/irq.h> |
4cb28ced | 25 | #include <linux/smpboot.h> |
cff7d378 | 26 | |
bb3632c6 | 27 | #include <trace/events/power.h> |
cff7d378 TG |
28 | #define CREATE_TRACE_POINTS |
29 | #include <trace/events/cpuhp.h> | |
1da177e4 | 30 | |
38498a67 TG |
31 | #include "smpboot.h" |
32 | ||
cff7d378 TG |
33 | /** |
34 | * cpuhp_cpu_state - Per cpu hotplug state storage | |
35 | * @state: The current cpu state | |
36 | * @target: The target state | |
4cb28ced TG |
37 | * @thread: Pointer to the hotplug thread |
38 | * @should_run: Thread should execute | |
39 | * @cb_stat: The state for a single callback (install/uninstall) | |
40 | * @cb: Single callback function (install/uninstall) | |
41 | * @result: Result of the operation | |
42 | * @done: Signal completion to the issuer of the task | |
cff7d378 TG |
43 | */ |
44 | struct cpuhp_cpu_state { | |
45 | enum cpuhp_state state; | |
46 | enum cpuhp_state target; | |
4cb28ced TG |
47 | #ifdef CONFIG_SMP |
48 | struct task_struct *thread; | |
49 | bool should_run; | |
50 | enum cpuhp_state cb_state; | |
51 | int (*cb)(unsigned int cpu); | |
52 | int result; | |
53 | struct completion done; | |
54 | #endif | |
cff7d378 TG |
55 | }; |
56 | ||
57 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state); | |
58 | ||
59 | /** | |
60 | * cpuhp_step - Hotplug state machine step | |
61 | * @name: Name of the step | |
62 | * @startup: Startup function of the step | |
63 | * @teardown: Teardown function of the step | |
64 | * @skip_onerr: Do not invoke the functions on error rollback | |
65 | * Will go away once the notifiers are gone | |
757c989b | 66 | * @cant_stop: Bringup/teardown can't be stopped at this step |
cff7d378 TG |
67 | */ |
68 | struct cpuhp_step { | |
69 | const char *name; | |
70 | int (*startup)(unsigned int cpu); | |
71 | int (*teardown)(unsigned int cpu); | |
72 | bool skip_onerr; | |
757c989b | 73 | bool cant_stop; |
cff7d378 TG |
74 | }; |
75 | ||
98f8cdce | 76 | static DEFINE_MUTEX(cpuhp_state_mutex); |
cff7d378 | 77 | static struct cpuhp_step cpuhp_bp_states[]; |
4baa0afc | 78 | static struct cpuhp_step cpuhp_ap_states[]; |
cff7d378 TG |
79 | |
80 | /** | |
81 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state | |
82 | * @cpu: The cpu for which the callback should be invoked | |
83 | * @step: The step in the state machine | |
84 | * @cb: The callback function to invoke | |
85 | * | |
86 | * Called from cpu hotplug and from the state register machinery | |
87 | */ | |
88 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state step, | |
89 | int (*cb)(unsigned int)) | |
90 | { | |
91 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
92 | int ret = 0; | |
93 | ||
94 | if (cb) { | |
95 | trace_cpuhp_enter(cpu, st->target, step, cb); | |
96 | ret = cb(cpu); | |
97 | trace_cpuhp_exit(cpu, st->state, step, ret); | |
98 | } | |
99 | return ret; | |
100 | } | |
101 | ||
98a79d6a | 102 | #ifdef CONFIG_SMP |
b3199c02 | 103 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 104 | static DEFINE_MUTEX(cpu_add_remove_lock); |
090e77c3 TG |
105 | bool cpuhp_tasks_frozen; |
106 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
1da177e4 | 107 | |
79a6cdeb | 108 | /* |
93ae4f97 SB |
109 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
110 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
111 | * The APIs cpu_notifier_register_begin/done() must be used to protect CPU | |
112 | * hotplug callback (un)registration performed using __register_cpu_notifier() | |
113 | * or __unregister_cpu_notifier(). | |
79a6cdeb LJ |
114 | */ |
115 | void cpu_maps_update_begin(void) | |
116 | { | |
117 | mutex_lock(&cpu_add_remove_lock); | |
118 | } | |
93ae4f97 | 119 | EXPORT_SYMBOL(cpu_notifier_register_begin); |
79a6cdeb LJ |
120 | |
121 | void cpu_maps_update_done(void) | |
122 | { | |
123 | mutex_unlock(&cpu_add_remove_lock); | |
124 | } | |
93ae4f97 | 125 | EXPORT_SYMBOL(cpu_notifier_register_done); |
79a6cdeb | 126 | |
5c113fbe | 127 | static RAW_NOTIFIER_HEAD(cpu_chain); |
1da177e4 | 128 | |
e3920fb4 RW |
129 | /* If set, cpu_up and cpu_down will return -EBUSY and do nothing. |
130 | * Should always be manipulated under cpu_add_remove_lock | |
131 | */ | |
132 | static int cpu_hotplug_disabled; | |
133 | ||
79a6cdeb LJ |
134 | #ifdef CONFIG_HOTPLUG_CPU |
135 | ||
d221938c GS |
136 | static struct { |
137 | struct task_struct *active_writer; | |
87af9e7f DH |
138 | /* wait queue to wake up the active_writer */ |
139 | wait_queue_head_t wq; | |
140 | /* verifies that no writer will get active while readers are active */ | |
141 | struct mutex lock; | |
d221938c GS |
142 | /* |
143 | * Also blocks the new readers during | |
144 | * an ongoing cpu hotplug operation. | |
145 | */ | |
87af9e7f | 146 | atomic_t refcount; |
a19423b9 GS |
147 | |
148 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
149 | struct lockdep_map dep_map; | |
150 | #endif | |
31950eb6 LT |
151 | } cpu_hotplug = { |
152 | .active_writer = NULL, | |
87af9e7f | 153 | .wq = __WAIT_QUEUE_HEAD_INITIALIZER(cpu_hotplug.wq), |
31950eb6 | 154 | .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock), |
a19423b9 GS |
155 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
156 | .dep_map = {.name = "cpu_hotplug.lock" }, | |
157 | #endif | |
31950eb6 | 158 | }; |
d221938c | 159 | |
a19423b9 GS |
160 | /* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */ |
161 | #define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map) | |
dd56af42 PM |
162 | #define cpuhp_lock_acquire_tryread() \ |
163 | lock_map_acquire_tryread(&cpu_hotplug.dep_map) | |
a19423b9 GS |
164 | #define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map) |
165 | #define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map) | |
166 | ||
62db99f4 | 167 | |
86ef5c9a | 168 | void get_online_cpus(void) |
a9d9baa1 | 169 | { |
d221938c GS |
170 | might_sleep(); |
171 | if (cpu_hotplug.active_writer == current) | |
aa953877 | 172 | return; |
a19423b9 | 173 | cpuhp_lock_acquire_read(); |
d221938c | 174 | mutex_lock(&cpu_hotplug.lock); |
87af9e7f | 175 | atomic_inc(&cpu_hotplug.refcount); |
d221938c | 176 | mutex_unlock(&cpu_hotplug.lock); |
a9d9baa1 | 177 | } |
86ef5c9a | 178 | EXPORT_SYMBOL_GPL(get_online_cpus); |
90d45d17 | 179 | |
86ef5c9a | 180 | void put_online_cpus(void) |
a9d9baa1 | 181 | { |
87af9e7f DH |
182 | int refcount; |
183 | ||
d221938c | 184 | if (cpu_hotplug.active_writer == current) |
aa953877 | 185 | return; |
075663d1 | 186 | |
87af9e7f DH |
187 | refcount = atomic_dec_return(&cpu_hotplug.refcount); |
188 | if (WARN_ON(refcount < 0)) /* try to fix things up */ | |
189 | atomic_inc(&cpu_hotplug.refcount); | |
190 | ||
191 | if (refcount <= 0 && waitqueue_active(&cpu_hotplug.wq)) | |
192 | wake_up(&cpu_hotplug.wq); | |
075663d1 | 193 | |
a19423b9 | 194 | cpuhp_lock_release(); |
d221938c | 195 | |
a9d9baa1 | 196 | } |
86ef5c9a | 197 | EXPORT_SYMBOL_GPL(put_online_cpus); |
a9d9baa1 | 198 | |
d221938c GS |
199 | /* |
200 | * This ensures that the hotplug operation can begin only when the | |
201 | * refcount goes to zero. | |
202 | * | |
203 | * Note that during a cpu-hotplug operation, the new readers, if any, | |
204 | * will be blocked by the cpu_hotplug.lock | |
205 | * | |
d2ba7e2a ON |
206 | * Since cpu_hotplug_begin() is always called after invoking |
207 | * cpu_maps_update_begin(), we can be sure that only one writer is active. | |
d221938c GS |
208 | * |
209 | * Note that theoretically, there is a possibility of a livelock: | |
210 | * - Refcount goes to zero, last reader wakes up the sleeping | |
211 | * writer. | |
212 | * - Last reader unlocks the cpu_hotplug.lock. | |
213 | * - A new reader arrives at this moment, bumps up the refcount. | |
214 | * - The writer acquires the cpu_hotplug.lock finds the refcount | |
215 | * non zero and goes to sleep again. | |
216 | * | |
217 | * However, this is very difficult to achieve in practice since | |
86ef5c9a | 218 | * get_online_cpus() not an api which is called all that often. |
d221938c GS |
219 | * |
220 | */ | |
b9d10be7 | 221 | void cpu_hotplug_begin(void) |
d221938c | 222 | { |
87af9e7f | 223 | DEFINE_WAIT(wait); |
d2ba7e2a | 224 | |
87af9e7f | 225 | cpu_hotplug.active_writer = current; |
a19423b9 | 226 | cpuhp_lock_acquire(); |
87af9e7f | 227 | |
d2ba7e2a ON |
228 | for (;;) { |
229 | mutex_lock(&cpu_hotplug.lock); | |
87af9e7f DH |
230 | prepare_to_wait(&cpu_hotplug.wq, &wait, TASK_UNINTERRUPTIBLE); |
231 | if (likely(!atomic_read(&cpu_hotplug.refcount))) | |
232 | break; | |
d221938c GS |
233 | mutex_unlock(&cpu_hotplug.lock); |
234 | schedule(); | |
d221938c | 235 | } |
87af9e7f | 236 | finish_wait(&cpu_hotplug.wq, &wait); |
d221938c GS |
237 | } |
238 | ||
b9d10be7 | 239 | void cpu_hotplug_done(void) |
d221938c GS |
240 | { |
241 | cpu_hotplug.active_writer = NULL; | |
242 | mutex_unlock(&cpu_hotplug.lock); | |
a19423b9 | 243 | cpuhp_lock_release(); |
d221938c | 244 | } |
79a6cdeb | 245 | |
16e53dbf SB |
246 | /* |
247 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
248 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
249 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
250 | * hotplug path before performing hotplug operations. So acquiring that lock | |
251 | * guarantees mutual exclusion from any currently running hotplug operations. | |
252 | */ | |
253 | void cpu_hotplug_disable(void) | |
254 | { | |
255 | cpu_maps_update_begin(); | |
89af7ba5 | 256 | cpu_hotplug_disabled++; |
16e53dbf SB |
257 | cpu_maps_update_done(); |
258 | } | |
32145c46 | 259 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
16e53dbf SB |
260 | |
261 | void cpu_hotplug_enable(void) | |
262 | { | |
263 | cpu_maps_update_begin(); | |
89af7ba5 | 264 | WARN_ON(--cpu_hotplug_disabled < 0); |
16e53dbf SB |
265 | cpu_maps_update_done(); |
266 | } | |
32145c46 | 267 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
b9d10be7 | 268 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 269 | |
1da177e4 | 270 | /* Need to know about CPUs going up/down? */ |
71cf5aee | 271 | int register_cpu_notifier(struct notifier_block *nb) |
1da177e4 | 272 | { |
bd5349cf | 273 | int ret; |
d221938c | 274 | cpu_maps_update_begin(); |
bd5349cf | 275 | ret = raw_notifier_chain_register(&cpu_chain, nb); |
d221938c | 276 | cpu_maps_update_done(); |
bd5349cf | 277 | return ret; |
1da177e4 | 278 | } |
65edc68c | 279 | |
71cf5aee | 280 | int __register_cpu_notifier(struct notifier_block *nb) |
93ae4f97 SB |
281 | { |
282 | return raw_notifier_chain_register(&cpu_chain, nb); | |
283 | } | |
284 | ||
090e77c3 | 285 | static int __cpu_notify(unsigned long val, unsigned int cpu, int nr_to_call, |
e9fb7631 AM |
286 | int *nr_calls) |
287 | { | |
090e77c3 TG |
288 | unsigned long mod = cpuhp_tasks_frozen ? CPU_TASKS_FROZEN : 0; |
289 | void *hcpu = (void *)(long)cpu; | |
290 | ||
e6bde73b AM |
291 | int ret; |
292 | ||
090e77c3 | 293 | ret = __raw_notifier_call_chain(&cpu_chain, val | mod, hcpu, nr_to_call, |
e9fb7631 | 294 | nr_calls); |
e6bde73b AM |
295 | |
296 | return notifier_to_errno(ret); | |
e9fb7631 AM |
297 | } |
298 | ||
090e77c3 | 299 | static int cpu_notify(unsigned long val, unsigned int cpu) |
e9fb7631 | 300 | { |
090e77c3 | 301 | return __cpu_notify(val, cpu, -1, NULL); |
e9fb7631 AM |
302 | } |
303 | ||
ba997462 TG |
304 | /* Notifier wrappers for transitioning to state machine */ |
305 | static int notify_prepare(unsigned int cpu) | |
306 | { | |
307 | int nr_calls = 0; | |
308 | int ret; | |
309 | ||
310 | ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls); | |
311 | if (ret) { | |
312 | nr_calls--; | |
313 | printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n", | |
314 | __func__, cpu); | |
315 | __cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL); | |
316 | } | |
317 | return ret; | |
318 | } | |
319 | ||
320 | static int notify_online(unsigned int cpu) | |
321 | { | |
322 | cpu_notify(CPU_ONLINE, cpu); | |
323 | return 0; | |
324 | } | |
325 | ||
4baa0afc TG |
326 | static int notify_starting(unsigned int cpu) |
327 | { | |
328 | cpu_notify(CPU_STARTING, cpu); | |
329 | return 0; | |
330 | } | |
331 | ||
8df3e07e TG |
332 | static int bringup_wait_for_ap(unsigned int cpu) |
333 | { | |
334 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
335 | ||
336 | wait_for_completion(&st->done); | |
337 | return st->result; | |
338 | } | |
339 | ||
ba997462 TG |
340 | static int bringup_cpu(unsigned int cpu) |
341 | { | |
342 | struct task_struct *idle = idle_thread_get(cpu); | |
343 | int ret; | |
344 | ||
345 | /* Arch-specific enabling code. */ | |
346 | ret = __cpu_up(cpu, idle); | |
347 | if (ret) { | |
348 | cpu_notify(CPU_UP_CANCELED, cpu); | |
349 | return ret; | |
350 | } | |
8df3e07e | 351 | ret = bringup_wait_for_ap(cpu); |
ba997462 | 352 | BUG_ON(!cpu_online(cpu)); |
8df3e07e | 353 | return ret; |
ba997462 TG |
354 | } |
355 | ||
2e1a3483 TG |
356 | /* |
357 | * Hotplug state machine related functions | |
358 | */ | |
359 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st, | |
360 | struct cpuhp_step *steps) | |
361 | { | |
362 | for (st->state++; st->state < st->target; st->state++) { | |
363 | struct cpuhp_step *step = steps + st->state; | |
364 | ||
365 | if (!step->skip_onerr) | |
366 | cpuhp_invoke_callback(cpu, st->state, step->startup); | |
367 | } | |
368 | } | |
369 | ||
370 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
371 | struct cpuhp_step *steps, enum cpuhp_state target) | |
372 | { | |
373 | enum cpuhp_state prev_state = st->state; | |
374 | int ret = 0; | |
375 | ||
376 | for (; st->state > target; st->state--) { | |
377 | struct cpuhp_step *step = steps + st->state; | |
378 | ||
379 | ret = cpuhp_invoke_callback(cpu, st->state, step->teardown); | |
380 | if (ret) { | |
381 | st->target = prev_state; | |
382 | undo_cpu_down(cpu, st, steps); | |
383 | break; | |
384 | } | |
385 | } | |
386 | return ret; | |
387 | } | |
388 | ||
389 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st, | |
390 | struct cpuhp_step *steps) | |
391 | { | |
392 | for (st->state--; st->state > st->target; st->state--) { | |
393 | struct cpuhp_step *step = steps + st->state; | |
394 | ||
395 | if (!step->skip_onerr) | |
396 | cpuhp_invoke_callback(cpu, st->state, step->teardown); | |
397 | } | |
398 | } | |
399 | ||
400 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
401 | struct cpuhp_step *steps, enum cpuhp_state target) | |
402 | { | |
403 | enum cpuhp_state prev_state = st->state; | |
404 | int ret = 0; | |
405 | ||
406 | while (st->state < target) { | |
407 | struct cpuhp_step *step; | |
408 | ||
409 | st->state++; | |
410 | step = steps + st->state; | |
411 | ret = cpuhp_invoke_callback(cpu, st->state, step->startup); | |
412 | if (ret) { | |
413 | st->target = prev_state; | |
414 | undo_cpu_up(cpu, st, steps); | |
415 | break; | |
416 | } | |
417 | } | |
418 | return ret; | |
419 | } | |
420 | ||
4cb28ced TG |
421 | /* |
422 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
423 | */ | |
424 | static void cpuhp_create(unsigned int cpu) | |
425 | { | |
426 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
427 | ||
428 | init_completion(&st->done); | |
429 | } | |
430 | ||
431 | static int cpuhp_should_run(unsigned int cpu) | |
432 | { | |
433 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
434 | ||
435 | return st->should_run; | |
436 | } | |
437 | ||
438 | /* Execute the teardown callbacks. Used to be CPU_DOWN_PREPARE */ | |
439 | static int cpuhp_ap_offline(unsigned int cpu, struct cpuhp_cpu_state *st) | |
440 | { | |
1cf4f629 | 441 | enum cpuhp_state target = max((int)st->target, CPUHP_TEARDOWN_CPU); |
4cb28ced TG |
442 | |
443 | return cpuhp_down_callbacks(cpu, st, cpuhp_ap_states, target); | |
444 | } | |
445 | ||
446 | /* Execute the online startup callbacks. Used to be CPU_ONLINE */ | |
447 | static int cpuhp_ap_online(unsigned int cpu, struct cpuhp_cpu_state *st) | |
448 | { | |
449 | return cpuhp_up_callbacks(cpu, st, cpuhp_ap_states, st->target); | |
450 | } | |
451 | ||
452 | /* | |
453 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
454 | * callbacks when a state gets [un]installed at runtime. | |
455 | */ | |
456 | static void cpuhp_thread_fun(unsigned int cpu) | |
457 | { | |
458 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
459 | int ret = 0; | |
460 | ||
461 | /* | |
462 | * Paired with the mb() in cpuhp_kick_ap_work and | |
463 | * cpuhp_invoke_ap_callback, so the work set is consistent visible. | |
464 | */ | |
465 | smp_mb(); | |
466 | if (!st->should_run) | |
467 | return; | |
468 | ||
469 | st->should_run = false; | |
470 | ||
471 | /* Single callback invocation for [un]install ? */ | |
472 | if (st->cb) { | |
473 | if (st->cb_state < CPUHP_AP_ONLINE) { | |
474 | local_irq_disable(); | |
475 | ret = cpuhp_invoke_callback(cpu, st->cb_state, st->cb); | |
476 | local_irq_enable(); | |
477 | } else { | |
478 | ret = cpuhp_invoke_callback(cpu, st->cb_state, st->cb); | |
479 | } | |
480 | } else { | |
1cf4f629 | 481 | /* Cannot happen .... */ |
8df3e07e | 482 | BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE); |
1cf4f629 | 483 | |
4cb28ced TG |
484 | /* Regular hotplug work */ |
485 | if (st->state < st->target) | |
486 | ret = cpuhp_ap_online(cpu, st); | |
487 | else if (st->state > st->target) | |
488 | ret = cpuhp_ap_offline(cpu, st); | |
489 | } | |
490 | st->result = ret; | |
491 | complete(&st->done); | |
492 | } | |
493 | ||
494 | /* Invoke a single callback on a remote cpu */ | |
495 | static int cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, | |
496 | int (*cb)(unsigned int)) | |
497 | { | |
498 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
499 | ||
500 | if (!cpu_online(cpu)) | |
501 | return 0; | |
502 | ||
503 | st->cb_state = state; | |
504 | st->cb = cb; | |
505 | /* | |
506 | * Make sure the above stores are visible before should_run becomes | |
507 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
508 | */ | |
509 | smp_mb(); | |
510 | st->should_run = true; | |
511 | wake_up_process(st->thread); | |
512 | wait_for_completion(&st->done); | |
513 | return st->result; | |
514 | } | |
515 | ||
516 | /* Regular hotplug invocation of the AP hotplug thread */ | |
1cf4f629 | 517 | static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st) |
4cb28ced | 518 | { |
4cb28ced TG |
519 | st->result = 0; |
520 | st->cb = NULL; | |
521 | /* | |
522 | * Make sure the above stores are visible before should_run becomes | |
523 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
524 | */ | |
525 | smp_mb(); | |
526 | st->should_run = true; | |
527 | wake_up_process(st->thread); | |
1cf4f629 TG |
528 | } |
529 | ||
530 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
531 | { | |
532 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
533 | enum cpuhp_state state = st->state; | |
534 | ||
535 | trace_cpuhp_enter(cpu, st->target, state, cpuhp_kick_ap_work); | |
536 | __cpuhp_kick_ap_work(st); | |
4cb28ced TG |
537 | wait_for_completion(&st->done); |
538 | trace_cpuhp_exit(cpu, st->state, state, st->result); | |
539 | return st->result; | |
540 | } | |
541 | ||
542 | static struct smp_hotplug_thread cpuhp_threads = { | |
543 | .store = &cpuhp_state.thread, | |
544 | .create = &cpuhp_create, | |
545 | .thread_should_run = cpuhp_should_run, | |
546 | .thread_fn = cpuhp_thread_fun, | |
547 | .thread_comm = "cpuhp/%u", | |
548 | .selfparking = true, | |
549 | }; | |
550 | ||
551 | void __init cpuhp_threads_init(void) | |
552 | { | |
553 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
554 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
555 | } | |
556 | ||
00b9b0af | 557 | #ifdef CONFIG_HOTPLUG_CPU |
1da177e4 | 558 | EXPORT_SYMBOL(register_cpu_notifier); |
93ae4f97 | 559 | EXPORT_SYMBOL(__register_cpu_notifier); |
71cf5aee | 560 | void unregister_cpu_notifier(struct notifier_block *nb) |
1da177e4 | 561 | { |
d221938c | 562 | cpu_maps_update_begin(); |
bd5349cf | 563 | raw_notifier_chain_unregister(&cpu_chain, nb); |
d221938c | 564 | cpu_maps_update_done(); |
1da177e4 LT |
565 | } |
566 | EXPORT_SYMBOL(unregister_cpu_notifier); | |
567 | ||
71cf5aee | 568 | void __unregister_cpu_notifier(struct notifier_block *nb) |
93ae4f97 SB |
569 | { |
570 | raw_notifier_chain_unregister(&cpu_chain, nb); | |
571 | } | |
572 | EXPORT_SYMBOL(__unregister_cpu_notifier); | |
573 | ||
e4cc2f87 AV |
574 | /** |
575 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
576 | * @cpu: a CPU id | |
577 | * | |
578 | * This function walks all processes, finds a valid mm struct for each one and | |
579 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
580 | * trivial, there are various non-obvious corner cases, which this function | |
581 | * tries to solve in a safe manner. | |
582 | * | |
583 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
584 | * be called only for an already offlined CPU. | |
585 | */ | |
cb79295e AV |
586 | void clear_tasks_mm_cpumask(int cpu) |
587 | { | |
588 | struct task_struct *p; | |
589 | ||
590 | /* | |
591 | * This function is called after the cpu is taken down and marked | |
592 | * offline, so its not like new tasks will ever get this cpu set in | |
593 | * their mm mask. -- Peter Zijlstra | |
594 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
595 | * full-fledged tasklist_lock. | |
596 | */ | |
e4cc2f87 | 597 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
598 | rcu_read_lock(); |
599 | for_each_process(p) { | |
600 | struct task_struct *t; | |
601 | ||
e4cc2f87 AV |
602 | /* |
603 | * Main thread might exit, but other threads may still have | |
604 | * a valid mm. Find one. | |
605 | */ | |
cb79295e AV |
606 | t = find_lock_task_mm(p); |
607 | if (!t) | |
608 | continue; | |
609 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
610 | task_unlock(t); | |
611 | } | |
612 | rcu_read_unlock(); | |
613 | } | |
614 | ||
b728ca06 | 615 | static inline void check_for_tasks(int dead_cpu) |
1da177e4 | 616 | { |
b728ca06 | 617 | struct task_struct *g, *p; |
1da177e4 | 618 | |
a75a6068 ON |
619 | read_lock(&tasklist_lock); |
620 | for_each_process_thread(g, p) { | |
b728ca06 KT |
621 | if (!p->on_rq) |
622 | continue; | |
623 | /* | |
624 | * We do the check with unlocked task_rq(p)->lock. | |
625 | * Order the reading to do not warn about a task, | |
626 | * which was running on this cpu in the past, and | |
627 | * it's just been woken on another cpu. | |
628 | */ | |
629 | rmb(); | |
630 | if (task_cpu(p) != dead_cpu) | |
631 | continue; | |
632 | ||
633 | pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n", | |
634 | p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags); | |
a75a6068 ON |
635 | } |
636 | read_unlock(&tasklist_lock); | |
1da177e4 LT |
637 | } |
638 | ||
98458172 TG |
639 | static void cpu_notify_nofail(unsigned long val, unsigned int cpu) |
640 | { | |
641 | BUG_ON(cpu_notify(val, cpu)); | |
642 | } | |
643 | ||
644 | static int notify_down_prepare(unsigned int cpu) | |
645 | { | |
646 | int err, nr_calls = 0; | |
647 | ||
648 | err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls); | |
649 | if (err) { | |
650 | nr_calls--; | |
651 | __cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL); | |
652 | pr_warn("%s: attempt to take down CPU %u failed\n", | |
653 | __func__, cpu); | |
654 | } | |
655 | return err; | |
656 | } | |
657 | ||
4baa0afc TG |
658 | static int notify_dying(unsigned int cpu) |
659 | { | |
660 | cpu_notify(CPU_DYING, cpu); | |
661 | return 0; | |
662 | } | |
663 | ||
1da177e4 | 664 | /* Take this CPU down. */ |
71cf5aee | 665 | static int take_cpu_down(void *_param) |
1da177e4 | 666 | { |
4baa0afc TG |
667 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
668 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 669 | int err, cpu = smp_processor_id(); |
1da177e4 | 670 | |
1da177e4 LT |
671 | /* Ensure this CPU doesn't handle any more interrupts. */ |
672 | err = __cpu_disable(); | |
673 | if (err < 0) | |
f3705136 | 674 | return err; |
1da177e4 | 675 | |
4baa0afc TG |
676 | /* Invoke the former CPU_DYING callbacks */ |
677 | for (; st->state > target; st->state--) { | |
678 | struct cpuhp_step *step = cpuhp_ap_states + st->state; | |
679 | ||
680 | cpuhp_invoke_callback(cpu, st->state, step->teardown); | |
681 | } | |
52c063d1 TG |
682 | /* Give up timekeeping duties */ |
683 | tick_handover_do_timer(); | |
14e568e7 | 684 | /* Park the stopper thread */ |
090e77c3 | 685 | stop_machine_park(cpu); |
f3705136 | 686 | return 0; |
1da177e4 LT |
687 | } |
688 | ||
98458172 | 689 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 690 | { |
e69aab13 | 691 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
98458172 | 692 | int err; |
1da177e4 | 693 | |
6acce3ef PZ |
694 | /* |
695 | * By now we've cleared cpu_active_mask, wait for all preempt-disabled | |
696 | * and RCU users of this state to go away such that all new such users | |
697 | * will observe it. | |
698 | * | |
699 | * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might | |
779de6ce | 700 | * not imply sync_sched(), so wait for both. |
106dd5af M |
701 | * |
702 | * Do sync before park smpboot threads to take care the rcu boost case. | |
6acce3ef | 703 | */ |
779de6ce PM |
704 | if (IS_ENABLED(CONFIG_PREEMPT)) |
705 | synchronize_rcu_mult(call_rcu, call_rcu_sched); | |
706 | else | |
707 | synchronize_rcu(); | |
6acce3ef | 708 | |
2a58c527 | 709 | /* Park the smpboot threads */ |
1cf4f629 | 710 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
2a58c527 | 711 | smpboot_park_threads(cpu); |
1cf4f629 | 712 | |
6acce3ef | 713 | /* |
a8994181 TG |
714 | * Prevent irq alloc/free while the dying cpu reorganizes the |
715 | * interrupt affinities. | |
6acce3ef | 716 | */ |
a8994181 | 717 | irq_lock_sparse(); |
6acce3ef | 718 | |
a8994181 TG |
719 | /* |
720 | * So now all preempt/rcu users must observe !cpu_active(). | |
721 | */ | |
090e77c3 | 722 | err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 723 | if (err) { |
1da177e4 | 724 | /* CPU didn't die: tell everyone. Can't complain. */ |
090e77c3 | 725 | cpu_notify_nofail(CPU_DOWN_FAILED, cpu); |
a8994181 | 726 | irq_unlock_sparse(); |
98458172 | 727 | return err; |
8fa1d7d3 | 728 | } |
04321587 | 729 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 730 | |
48c5ccae PZ |
731 | /* |
732 | * The migration_call() CPU_DYING callback will have removed all | |
733 | * runnable tasks from the cpu, there's only the idle task left now | |
734 | * that the migration thread is done doing the stop_machine thing. | |
51a96c77 PZ |
735 | * |
736 | * Wait for the stop thread to go away. | |
48c5ccae | 737 | */ |
e69aab13 TG |
738 | wait_for_completion(&st->done); |
739 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); | |
1da177e4 | 740 | |
a8994181 TG |
741 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
742 | irq_unlock_sparse(); | |
743 | ||
345527b1 | 744 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
745 | /* This actually kills the CPU. */ |
746 | __cpu_die(cpu); | |
747 | ||
a49b116d | 748 | tick_cleanup_dead_cpu(cpu); |
98458172 TG |
749 | return 0; |
750 | } | |
1da177e4 | 751 | |
98458172 TG |
752 | static int notify_dead(unsigned int cpu) |
753 | { | |
754 | cpu_notify_nofail(CPU_DEAD, cpu); | |
1da177e4 | 755 | check_for_tasks(cpu); |
98458172 TG |
756 | return 0; |
757 | } | |
758 | ||
71f87b2f TG |
759 | static void cpuhp_complete_idle_dead(void *arg) |
760 | { | |
761 | struct cpuhp_cpu_state *st = arg; | |
762 | ||
763 | complete(&st->done); | |
764 | } | |
765 | ||
e69aab13 TG |
766 | void cpuhp_report_idle_dead(void) |
767 | { | |
768 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
769 | ||
770 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
27d50c7e | 771 | rcu_report_dead(smp_processor_id()); |
71f87b2f TG |
772 | st->state = CPUHP_AP_IDLE_DEAD; |
773 | /* | |
774 | * We cannot call complete after rcu_report_dead() so we delegate it | |
775 | * to an online cpu. | |
776 | */ | |
777 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
778 | cpuhp_complete_idle_dead, st, 0); | |
e69aab13 TG |
779 | } |
780 | ||
cff7d378 TG |
781 | #else |
782 | #define notify_down_prepare NULL | |
783 | #define takedown_cpu NULL | |
784 | #define notify_dead NULL | |
4baa0afc | 785 | #define notify_dying NULL |
cff7d378 TG |
786 | #endif |
787 | ||
788 | #ifdef CONFIG_HOTPLUG_CPU | |
cff7d378 | 789 | |
98458172 | 790 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
791 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
792 | enum cpuhp_state target) | |
98458172 | 793 | { |
cff7d378 TG |
794 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
795 | int prev_state, ret = 0; | |
796 | bool hasdied = false; | |
98458172 TG |
797 | |
798 | if (num_online_cpus() == 1) | |
799 | return -EBUSY; | |
800 | ||
757c989b | 801 | if (!cpu_present(cpu)) |
98458172 TG |
802 | return -EINVAL; |
803 | ||
804 | cpu_hotplug_begin(); | |
805 | ||
806 | cpuhp_tasks_frozen = tasks_frozen; | |
807 | ||
cff7d378 | 808 | prev_state = st->state; |
af1f4045 | 809 | st->target = target; |
1cf4f629 TG |
810 | /* |
811 | * If the current CPU state is in the range of the AP hotplug thread, | |
812 | * then we need to kick the thread. | |
813 | */ | |
8df3e07e | 814 | if (st->state > CPUHP_TEARDOWN_CPU) { |
1cf4f629 TG |
815 | ret = cpuhp_kick_ap_work(cpu); |
816 | /* | |
817 | * The AP side has done the error rollback already. Just | |
818 | * return the error code.. | |
819 | */ | |
820 | if (ret) | |
821 | goto out; | |
822 | ||
823 | /* | |
824 | * We might have stopped still in the range of the AP hotplug | |
825 | * thread. Nothing to do anymore. | |
826 | */ | |
8df3e07e | 827 | if (st->state > CPUHP_TEARDOWN_CPU) |
1cf4f629 TG |
828 | goto out; |
829 | } | |
830 | /* | |
8df3e07e | 831 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
1cf4f629 TG |
832 | * to do the further cleanups. |
833 | */ | |
2e1a3483 | 834 | ret = cpuhp_down_callbacks(cpu, st, cpuhp_bp_states, target); |
98458172 | 835 | |
cff7d378 | 836 | hasdied = prev_state != st->state && st->state == CPUHP_OFFLINE; |
1cf4f629 | 837 | out: |
d221938c | 838 | cpu_hotplug_done(); |
cff7d378 TG |
839 | /* This post dead nonsense must die */ |
840 | if (!ret && hasdied) | |
090e77c3 | 841 | cpu_notify_nofail(CPU_POST_DEAD, cpu); |
cff7d378 | 842 | return ret; |
e3920fb4 RW |
843 | } |
844 | ||
af1f4045 | 845 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 846 | { |
9ea09af3 | 847 | int err; |
e3920fb4 | 848 | |
d221938c | 849 | cpu_maps_update_begin(); |
e761b772 MK |
850 | |
851 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 852 | err = -EBUSY; |
e761b772 MK |
853 | goto out; |
854 | } | |
855 | ||
af1f4045 | 856 | err = _cpu_down(cpu, 0, target); |
e3920fb4 | 857 | |
e761b772 | 858 | out: |
d221938c | 859 | cpu_maps_update_done(); |
1da177e4 LT |
860 | return err; |
861 | } | |
af1f4045 TG |
862 | int cpu_down(unsigned int cpu) |
863 | { | |
864 | return do_cpu_down(cpu, CPUHP_OFFLINE); | |
865 | } | |
b62b8ef9 | 866 | EXPORT_SYMBOL(cpu_down); |
1da177e4 LT |
867 | #endif /*CONFIG_HOTPLUG_CPU*/ |
868 | ||
4baa0afc TG |
869 | /** |
870 | * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers | |
871 | * @cpu: cpu that just started | |
872 | * | |
873 | * This function calls the cpu_chain notifiers with CPU_STARTING. | |
874 | * It must be called by the arch code on the new cpu, before the new cpu | |
875 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
876 | */ | |
877 | void notify_cpu_starting(unsigned int cpu) | |
878 | { | |
879 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
880 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
881 | ||
882 | while (st->state < target) { | |
883 | struct cpuhp_step *step; | |
884 | ||
885 | st->state++; | |
886 | step = cpuhp_ap_states + st->state; | |
887 | cpuhp_invoke_callback(cpu, st->state, step->startup); | |
888 | } | |
889 | } | |
890 | ||
949338e3 TG |
891 | /* |
892 | * Called from the idle task. We need to set active here, so we can kick off | |
8df3e07e TG |
893 | * the stopper thread and unpark the smpboot threads. If the target state is |
894 | * beyond CPUHP_AP_ONLINE_IDLE we kick cpuhp thread and let it bring up the | |
895 | * cpu further. | |
949338e3 | 896 | */ |
8df3e07e | 897 | void cpuhp_online_idle(enum cpuhp_state state) |
949338e3 | 898 | { |
8df3e07e TG |
899 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
900 | unsigned int cpu = smp_processor_id(); | |
901 | ||
902 | /* Happens for the boot cpu */ | |
903 | if (state != CPUHP_AP_ONLINE_IDLE) | |
904 | return; | |
905 | ||
906 | st->state = CPUHP_AP_ONLINE_IDLE; | |
1cf4f629 | 907 | |
949338e3 TG |
908 | /* The cpu is marked online, set it active now */ |
909 | set_cpu_active(cpu, true); | |
8df3e07e | 910 | /* Unpark the stopper thread and the hotplug thread of this cpu */ |
949338e3 | 911 | stop_machine_unpark(cpu); |
1cf4f629 | 912 | kthread_unpark(st->thread); |
8df3e07e TG |
913 | |
914 | /* Should we go further up ? */ | |
915 | if (st->target > CPUHP_AP_ONLINE_IDLE) | |
916 | __cpuhp_kick_ap_work(st); | |
917 | else | |
918 | complete(&st->done); | |
949338e3 TG |
919 | } |
920 | ||
e3920fb4 | 921 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 922 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 923 | { |
cff7d378 | 924 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 925 | struct task_struct *idle; |
2e1a3483 | 926 | int ret = 0; |
1da177e4 | 927 | |
d221938c | 928 | cpu_hotplug_begin(); |
38498a67 | 929 | |
757c989b | 930 | if (!cpu_present(cpu)) { |
5e5041f3 YI |
931 | ret = -EINVAL; |
932 | goto out; | |
933 | } | |
934 | ||
757c989b TG |
935 | /* |
936 | * The caller of do_cpu_up might have raced with another | |
937 | * caller. Ignore it for now. | |
938 | */ | |
939 | if (st->state >= target) | |
38498a67 | 940 | goto out; |
757c989b TG |
941 | |
942 | if (st->state == CPUHP_OFFLINE) { | |
943 | /* Let it fail before we try to bring the cpu up */ | |
944 | idle = idle_thread_get(cpu); | |
945 | if (IS_ERR(idle)) { | |
946 | ret = PTR_ERR(idle); | |
947 | goto out; | |
948 | } | |
3bb5d2ee | 949 | } |
38498a67 | 950 | |
ba997462 TG |
951 | cpuhp_tasks_frozen = tasks_frozen; |
952 | ||
af1f4045 | 953 | st->target = target; |
1cf4f629 TG |
954 | /* |
955 | * If the current CPU state is in the range of the AP hotplug thread, | |
956 | * then we need to kick the thread once more. | |
957 | */ | |
8df3e07e | 958 | if (st->state > CPUHP_BRINGUP_CPU) { |
1cf4f629 TG |
959 | ret = cpuhp_kick_ap_work(cpu); |
960 | /* | |
961 | * The AP side has done the error rollback already. Just | |
962 | * return the error code.. | |
963 | */ | |
964 | if (ret) | |
965 | goto out; | |
966 | } | |
967 | ||
968 | /* | |
969 | * Try to reach the target state. We max out on the BP at | |
8df3e07e | 970 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
1cf4f629 TG |
971 | * responsible for bringing it up to the target state. |
972 | */ | |
8df3e07e | 973 | target = min((int)target, CPUHP_BRINGUP_CPU); |
2e1a3483 | 974 | ret = cpuhp_up_callbacks(cpu, st, cpuhp_bp_states, target); |
38498a67 | 975 | out: |
d221938c | 976 | cpu_hotplug_done(); |
e3920fb4 RW |
977 | return ret; |
978 | } | |
979 | ||
af1f4045 | 980 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
981 | { |
982 | int err = 0; | |
cf23422b | 983 | |
e0b582ec | 984 | if (!cpu_possible(cpu)) { |
84117da5 FF |
985 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
986 | cpu); | |
87d5e023 | 987 | #if defined(CONFIG_IA64) |
84117da5 | 988 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
989 | #endif |
990 | return -EINVAL; | |
991 | } | |
e3920fb4 | 992 | |
01b0f197 TK |
993 | err = try_online_node(cpu_to_node(cpu)); |
994 | if (err) | |
995 | return err; | |
cf23422b | 996 | |
d221938c | 997 | cpu_maps_update_begin(); |
e761b772 MK |
998 | |
999 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 1000 | err = -EBUSY; |
e761b772 MK |
1001 | goto out; |
1002 | } | |
1003 | ||
af1f4045 | 1004 | err = _cpu_up(cpu, 0, target); |
e761b772 | 1005 | out: |
d221938c | 1006 | cpu_maps_update_done(); |
e3920fb4 RW |
1007 | return err; |
1008 | } | |
af1f4045 TG |
1009 | |
1010 | int cpu_up(unsigned int cpu) | |
1011 | { | |
1012 | return do_cpu_up(cpu, CPUHP_ONLINE); | |
1013 | } | |
a513f6ba | 1014 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 1015 | |
f3de4be9 | 1016 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 1017 | static cpumask_var_t frozen_cpus; |
e3920fb4 RW |
1018 | |
1019 | int disable_nonboot_cpus(void) | |
1020 | { | |
e9a5f426 | 1021 | int cpu, first_cpu, error = 0; |
e3920fb4 | 1022 | |
d221938c | 1023 | cpu_maps_update_begin(); |
e0b582ec | 1024 | first_cpu = cpumask_first(cpu_online_mask); |
9ee349ad XF |
1025 | /* |
1026 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
1027 | * with the userspace trying to use the CPU hotplug at the same time |
1028 | */ | |
e0b582ec | 1029 | cpumask_clear(frozen_cpus); |
6ad4c188 | 1030 | |
84117da5 | 1031 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 RW |
1032 | for_each_online_cpu(cpu) { |
1033 | if (cpu == first_cpu) | |
1034 | continue; | |
bb3632c6 | 1035 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 1036 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 1037 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 1038 | if (!error) |
e0b582ec | 1039 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 1040 | else { |
84117da5 | 1041 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
1042 | break; |
1043 | } | |
1044 | } | |
86886e55 | 1045 | |
89af7ba5 | 1046 | if (!error) |
e3920fb4 | 1047 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 1048 | else |
84117da5 | 1049 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
1050 | |
1051 | /* | |
1052 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
1053 | * this even in case of failure as all disable_nonboot_cpus() users are | |
1054 | * supposed to do enable_nonboot_cpus() on the failure path. | |
1055 | */ | |
1056 | cpu_hotplug_disabled++; | |
1057 | ||
d221938c | 1058 | cpu_maps_update_done(); |
e3920fb4 RW |
1059 | return error; |
1060 | } | |
1061 | ||
d0af9eed SS |
1062 | void __weak arch_enable_nonboot_cpus_begin(void) |
1063 | { | |
1064 | } | |
1065 | ||
1066 | void __weak arch_enable_nonboot_cpus_end(void) | |
1067 | { | |
1068 | } | |
1069 | ||
71cf5aee | 1070 | void enable_nonboot_cpus(void) |
e3920fb4 RW |
1071 | { |
1072 | int cpu, error; | |
1073 | ||
1074 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 1075 | cpu_maps_update_begin(); |
89af7ba5 | 1076 | WARN_ON(--cpu_hotplug_disabled < 0); |
e0b582ec | 1077 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 1078 | goto out; |
e3920fb4 | 1079 | |
84117da5 | 1080 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
1081 | |
1082 | arch_enable_nonboot_cpus_begin(); | |
1083 | ||
e0b582ec | 1084 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 1085 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 1086 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 1087 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 1088 | if (!error) { |
84117da5 | 1089 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
1090 | continue; |
1091 | } | |
84117da5 | 1092 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 1093 | } |
d0af9eed SS |
1094 | |
1095 | arch_enable_nonboot_cpus_end(); | |
1096 | ||
e0b582ec | 1097 | cpumask_clear(frozen_cpus); |
1d64b9cb | 1098 | out: |
d221938c | 1099 | cpu_maps_update_done(); |
1da177e4 | 1100 | } |
e0b582ec | 1101 | |
d7268a31 | 1102 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
1103 | { |
1104 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1105 | return -ENOMEM; | |
1106 | return 0; | |
1107 | } | |
1108 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 1109 | |
79cfbdfa SB |
1110 | /* |
1111 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1112 | * ensure that the state of the system with respect to the tasks being frozen | |
1113 | * or not, as reported by the notification, remains unchanged *throughout the | |
1114 | * duration* of the execution of the callbacks. | |
1115 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1116 | * | |
1117 | * This synchronization is implemented by mutually excluding regular CPU | |
1118 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1119 | * Hibernate notifications. | |
1120 | */ | |
1121 | static int | |
1122 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1123 | unsigned long action, void *ptr) | |
1124 | { | |
1125 | switch (action) { | |
1126 | ||
1127 | case PM_SUSPEND_PREPARE: | |
1128 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 1129 | cpu_hotplug_disable(); |
79cfbdfa SB |
1130 | break; |
1131 | ||
1132 | case PM_POST_SUSPEND: | |
1133 | case PM_POST_HIBERNATION: | |
16e53dbf | 1134 | cpu_hotplug_enable(); |
79cfbdfa SB |
1135 | break; |
1136 | ||
1137 | default: | |
1138 | return NOTIFY_DONE; | |
1139 | } | |
1140 | ||
1141 | return NOTIFY_OK; | |
1142 | } | |
1143 | ||
1144 | ||
d7268a31 | 1145 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 1146 | { |
6e32d479 FY |
1147 | /* |
1148 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1149 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1150 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1151 | */ | |
79cfbdfa SB |
1152 | pm_notifier(cpu_hotplug_pm_callback, 0); |
1153 | return 0; | |
1154 | } | |
1155 | core_initcall(cpu_hotplug_pm_sync_init); | |
1156 | ||
f3de4be9 | 1157 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec MK |
1158 | |
1159 | #endif /* CONFIG_SMP */ | |
b8d317d1 | 1160 | |
cff7d378 TG |
1161 | /* Boot processor state steps */ |
1162 | static struct cpuhp_step cpuhp_bp_states[] = { | |
1163 | [CPUHP_OFFLINE] = { | |
1164 | .name = "offline", | |
1165 | .startup = NULL, | |
1166 | .teardown = NULL, | |
1167 | }, | |
1168 | #ifdef CONFIG_SMP | |
1169 | [CPUHP_CREATE_THREADS]= { | |
1170 | .name = "threads:create", | |
1171 | .startup = smpboot_create_threads, | |
1172 | .teardown = NULL, | |
757c989b | 1173 | .cant_stop = true, |
cff7d378 | 1174 | }, |
d10ef6f9 TG |
1175 | /* |
1176 | * Preparatory and dead notifiers. Will be replaced once the notifiers | |
1177 | * are converted to states. | |
1178 | */ | |
cff7d378 TG |
1179 | [CPUHP_NOTIFY_PREPARE] = { |
1180 | .name = "notify:prepare", | |
1181 | .startup = notify_prepare, | |
1182 | .teardown = notify_dead, | |
1183 | .skip_onerr = true, | |
757c989b | 1184 | .cant_stop = true, |
cff7d378 | 1185 | }, |
d10ef6f9 | 1186 | /* Kicks the plugged cpu into life */ |
cff7d378 TG |
1187 | [CPUHP_BRINGUP_CPU] = { |
1188 | .name = "cpu:bringup", | |
1189 | .startup = bringup_cpu, | |
4baa0afc | 1190 | .teardown = NULL, |
757c989b | 1191 | .cant_stop = true, |
4baa0afc | 1192 | }, |
d10ef6f9 TG |
1193 | /* |
1194 | * Handled on controll processor until the plugged processor manages | |
1195 | * this itself. | |
1196 | */ | |
4baa0afc TG |
1197 | [CPUHP_TEARDOWN_CPU] = { |
1198 | .name = "cpu:teardown", | |
1199 | .startup = NULL, | |
cff7d378 | 1200 | .teardown = takedown_cpu, |
757c989b | 1201 | .cant_stop = true, |
cff7d378 | 1202 | }, |
cff7d378 | 1203 | #endif |
cff7d378 TG |
1204 | }; |
1205 | ||
4baa0afc TG |
1206 | /* Application processor state steps */ |
1207 | static struct cpuhp_step cpuhp_ap_states[] = { | |
1208 | #ifdef CONFIG_SMP | |
d10ef6f9 TG |
1209 | /* Final state before CPU kills itself */ |
1210 | [CPUHP_AP_IDLE_DEAD] = { | |
1211 | .name = "idle:dead", | |
1212 | }, | |
1213 | /* | |
1214 | * Last state before CPU enters the idle loop to die. Transient state | |
1215 | * for synchronization. | |
1216 | */ | |
1217 | [CPUHP_AP_OFFLINE] = { | |
1218 | .name = "ap:offline", | |
1219 | .cant_stop = true, | |
1220 | }, | |
1221 | /* | |
1222 | * Low level startup/teardown notifiers. Run with interrupts | |
1223 | * disabled. Will be removed once the notifiers are converted to | |
1224 | * states. | |
1225 | */ | |
4baa0afc TG |
1226 | [CPUHP_AP_NOTIFY_STARTING] = { |
1227 | .name = "notify:starting", | |
1228 | .startup = notify_starting, | |
1229 | .teardown = notify_dying, | |
1230 | .skip_onerr = true, | |
757c989b | 1231 | .cant_stop = true, |
4baa0afc | 1232 | }, |
d10ef6f9 TG |
1233 | /* Entry state on starting. Interrupts enabled from here on. Transient |
1234 | * state for synchronsization */ | |
1235 | [CPUHP_AP_ONLINE] = { | |
1236 | .name = "ap:online", | |
1237 | }, | |
1238 | /* Handle smpboot threads park/unpark */ | |
1cf4f629 TG |
1239 | [CPUHP_AP_SMPBOOT_THREADS] = { |
1240 | .name = "smpboot:threads", | |
1241 | .startup = smpboot_unpark_threads, | |
2a58c527 | 1242 | .teardown = NULL, |
1cf4f629 | 1243 | }, |
d10ef6f9 TG |
1244 | /* |
1245 | * Online/down_prepare notifiers. Will be removed once the notifiers | |
1246 | * are converted to states. | |
1247 | */ | |
1cf4f629 TG |
1248 | [CPUHP_AP_NOTIFY_ONLINE] = { |
1249 | .name = "notify:online", | |
1250 | .startup = notify_online, | |
1251 | .teardown = notify_down_prepare, | |
1252 | }, | |
4baa0afc | 1253 | #endif |
d10ef6f9 TG |
1254 | /* |
1255 | * The dynamically registered state space is here | |
1256 | */ | |
1257 | ||
1258 | /* CPU is fully up and running. */ | |
4baa0afc TG |
1259 | [CPUHP_ONLINE] = { |
1260 | .name = "online", | |
1261 | .startup = NULL, | |
1262 | .teardown = NULL, | |
1263 | }, | |
1264 | }; | |
1265 | ||
5b7aa87e TG |
1266 | /* Sanity check for callbacks */ |
1267 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1268 | { | |
1269 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1270 | return -EINVAL; | |
1271 | return 0; | |
1272 | } | |
1273 | ||
98f8cdce TG |
1274 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
1275 | { | |
d10ef6f9 TG |
1276 | /* |
1277 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
1278 | * purposes as that state is handled explicitely in cpu_down. | |
1279 | */ | |
1280 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
98f8cdce TG |
1281 | } |
1282 | ||
1283 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) | |
1284 | { | |
1285 | struct cpuhp_step *sp; | |
1286 | ||
1287 | sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states; | |
1288 | return sp + state; | |
1289 | } | |
1290 | ||
5b7aa87e TG |
1291 | static void cpuhp_store_callbacks(enum cpuhp_state state, |
1292 | const char *name, | |
1293 | int (*startup)(unsigned int cpu), | |
1294 | int (*teardown)(unsigned int cpu)) | |
1295 | { | |
1296 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1297 | struct cpuhp_step *sp; | |
1298 | ||
1299 | mutex_lock(&cpuhp_state_mutex); | |
1300 | sp = cpuhp_get_step(state); | |
1301 | sp->startup = startup; | |
1302 | sp->teardown = teardown; | |
1303 | sp->name = name; | |
1304 | mutex_unlock(&cpuhp_state_mutex); | |
1305 | } | |
1306 | ||
1307 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1308 | { | |
1309 | return cpuhp_get_step(state)->teardown; | |
1310 | } | |
1311 | ||
5b7aa87e TG |
1312 | /* |
1313 | * Call the startup/teardown function for a step either on the AP or | |
1314 | * on the current CPU. | |
1315 | */ | |
1316 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, | |
1317 | int (*cb)(unsigned int), bool bringup) | |
1318 | { | |
1319 | int ret; | |
1320 | ||
1321 | if (!cb) | |
1322 | return 0; | |
5b7aa87e TG |
1323 | /* |
1324 | * The non AP bound callbacks can fail on bringup. On teardown | |
1325 | * e.g. module removal we crash for now. | |
1326 | */ | |
1cf4f629 TG |
1327 | #ifdef CONFIG_SMP |
1328 | if (cpuhp_is_ap_state(state)) | |
1329 | ret = cpuhp_invoke_ap_callback(cpu, state, cb); | |
1330 | else | |
1331 | ret = cpuhp_invoke_callback(cpu, state, cb); | |
1332 | #else | |
1333 | ret = cpuhp_invoke_callback(cpu, state, cb); | |
1334 | #endif | |
5b7aa87e TG |
1335 | BUG_ON(ret && !bringup); |
1336 | return ret; | |
1337 | } | |
1338 | ||
1339 | /* | |
1340 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1341 | * | |
1342 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1343 | */ | |
1344 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
1345 | int (*teardown)(unsigned int cpu)) | |
1346 | { | |
1347 | int cpu; | |
1348 | ||
1349 | if (!teardown) | |
1350 | return; | |
1351 | ||
1352 | /* Roll back the already executed steps on the other cpus */ | |
1353 | for_each_present_cpu(cpu) { | |
1354 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1355 | int cpustate = st->state; | |
1356 | ||
1357 | if (cpu >= failedcpu) | |
1358 | break; | |
1359 | ||
1360 | /* Did we invoke the startup call on that cpu ? */ | |
1361 | if (cpustate >= state) | |
1362 | cpuhp_issue_call(cpu, state, teardown, false); | |
1363 | } | |
1364 | } | |
1365 | ||
1366 | /* | |
1367 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1368 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1369 | * by having no name assigned. | |
1370 | */ | |
1371 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1372 | { | |
1373 | enum cpuhp_state i; | |
1374 | ||
1375 | mutex_lock(&cpuhp_state_mutex); | |
1cf4f629 TG |
1376 | for (i = CPUHP_AP_ONLINE_DYN; i <= CPUHP_AP_ONLINE_DYN_END; i++) { |
1377 | if (cpuhp_ap_states[i].name) | |
5b7aa87e TG |
1378 | continue; |
1379 | ||
1cf4f629 | 1380 | cpuhp_ap_states[i].name = "Reserved"; |
5b7aa87e TG |
1381 | mutex_unlock(&cpuhp_state_mutex); |
1382 | return i; | |
1383 | } | |
1384 | mutex_unlock(&cpuhp_state_mutex); | |
1385 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1386 | return -ENOSPC; | |
1387 | } | |
1388 | ||
1389 | /** | |
1390 | * __cpuhp_setup_state - Setup the callbacks for an hotplug machine state | |
1391 | * @state: The state to setup | |
1392 | * @invoke: If true, the startup function is invoked for cpus where | |
1393 | * cpu state >= @state | |
1394 | * @startup: startup callback function | |
1395 | * @teardown: teardown callback function | |
1396 | * | |
1397 | * Returns 0 if successful, otherwise a proper error code | |
1398 | */ | |
1399 | int __cpuhp_setup_state(enum cpuhp_state state, | |
1400 | const char *name, bool invoke, | |
1401 | int (*startup)(unsigned int cpu), | |
1402 | int (*teardown)(unsigned int cpu)) | |
1403 | { | |
1404 | int cpu, ret = 0; | |
1405 | int dyn_state = 0; | |
1406 | ||
1407 | if (cpuhp_cb_check(state) || !name) | |
1408 | return -EINVAL; | |
1409 | ||
1410 | get_online_cpus(); | |
1411 | ||
1412 | /* currently assignments for the ONLINE state are possible */ | |
1cf4f629 | 1413 | if (state == CPUHP_AP_ONLINE_DYN) { |
5b7aa87e TG |
1414 | dyn_state = 1; |
1415 | ret = cpuhp_reserve_state(state); | |
1416 | if (ret < 0) | |
1417 | goto out; | |
1418 | state = ret; | |
1419 | } | |
1420 | ||
1421 | cpuhp_store_callbacks(state, name, startup, teardown); | |
1422 | ||
1423 | if (!invoke || !startup) | |
1424 | goto out; | |
1425 | ||
1426 | /* | |
1427 | * Try to call the startup callback for each present cpu | |
1428 | * depending on the hotplug state of the cpu. | |
1429 | */ | |
1430 | for_each_present_cpu(cpu) { | |
1431 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1432 | int cpustate = st->state; | |
1433 | ||
1434 | if (cpustate < state) | |
1435 | continue; | |
1436 | ||
1437 | ret = cpuhp_issue_call(cpu, state, startup, true); | |
1438 | if (ret) { | |
1439 | cpuhp_rollback_install(cpu, state, teardown); | |
1440 | cpuhp_store_callbacks(state, NULL, NULL, NULL); | |
1441 | goto out; | |
1442 | } | |
1443 | } | |
1444 | out: | |
1445 | put_online_cpus(); | |
1446 | if (!ret && dyn_state) | |
1447 | return state; | |
1448 | return ret; | |
1449 | } | |
1450 | EXPORT_SYMBOL(__cpuhp_setup_state); | |
1451 | ||
1452 | /** | |
1453 | * __cpuhp_remove_state - Remove the callbacks for an hotplug machine state | |
1454 | * @state: The state to remove | |
1455 | * @invoke: If true, the teardown function is invoked for cpus where | |
1456 | * cpu state >= @state | |
1457 | * | |
1458 | * The teardown callback is currently not allowed to fail. Think | |
1459 | * about module removal! | |
1460 | */ | |
1461 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
1462 | { | |
1463 | int (*teardown)(unsigned int cpu) = cpuhp_get_teardown_cb(state); | |
1464 | int cpu; | |
1465 | ||
1466 | BUG_ON(cpuhp_cb_check(state)); | |
1467 | ||
1468 | get_online_cpus(); | |
1469 | ||
1470 | if (!invoke || !teardown) | |
1471 | goto remove; | |
1472 | ||
1473 | /* | |
1474 | * Call the teardown callback for each present cpu depending | |
1475 | * on the hotplug state of the cpu. This function is not | |
1476 | * allowed to fail currently! | |
1477 | */ | |
1478 | for_each_present_cpu(cpu) { | |
1479 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1480 | int cpustate = st->state; | |
1481 | ||
1482 | if (cpustate >= state) | |
1483 | cpuhp_issue_call(cpu, state, teardown, false); | |
1484 | } | |
1485 | remove: | |
1486 | cpuhp_store_callbacks(state, NULL, NULL, NULL); | |
1487 | put_online_cpus(); | |
1488 | } | |
1489 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
1490 | ||
98f8cdce TG |
1491 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
1492 | static ssize_t show_cpuhp_state(struct device *dev, | |
1493 | struct device_attribute *attr, char *buf) | |
1494 | { | |
1495 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1496 | ||
1497 | return sprintf(buf, "%d\n", st->state); | |
1498 | } | |
1499 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
1500 | ||
757c989b TG |
1501 | static ssize_t write_cpuhp_target(struct device *dev, |
1502 | struct device_attribute *attr, | |
1503 | const char *buf, size_t count) | |
1504 | { | |
1505 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1506 | struct cpuhp_step *sp; | |
1507 | int target, ret; | |
1508 | ||
1509 | ret = kstrtoint(buf, 10, &target); | |
1510 | if (ret) | |
1511 | return ret; | |
1512 | ||
1513 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
1514 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
1515 | return -EINVAL; | |
1516 | #else | |
1517 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
1518 | return -EINVAL; | |
1519 | #endif | |
1520 | ||
1521 | ret = lock_device_hotplug_sysfs(); | |
1522 | if (ret) | |
1523 | return ret; | |
1524 | ||
1525 | mutex_lock(&cpuhp_state_mutex); | |
1526 | sp = cpuhp_get_step(target); | |
1527 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
1528 | mutex_unlock(&cpuhp_state_mutex); | |
1529 | if (ret) | |
1530 | return ret; | |
1531 | ||
1532 | if (st->state < target) | |
1533 | ret = do_cpu_up(dev->id, target); | |
1534 | else | |
1535 | ret = do_cpu_down(dev->id, target); | |
1536 | ||
1537 | unlock_device_hotplug(); | |
1538 | return ret ? ret : count; | |
1539 | } | |
1540 | ||
98f8cdce TG |
1541 | static ssize_t show_cpuhp_target(struct device *dev, |
1542 | struct device_attribute *attr, char *buf) | |
1543 | { | |
1544 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1545 | ||
1546 | return sprintf(buf, "%d\n", st->target); | |
1547 | } | |
757c989b | 1548 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
98f8cdce TG |
1549 | |
1550 | static struct attribute *cpuhp_cpu_attrs[] = { | |
1551 | &dev_attr_state.attr, | |
1552 | &dev_attr_target.attr, | |
1553 | NULL | |
1554 | }; | |
1555 | ||
1556 | static struct attribute_group cpuhp_cpu_attr_group = { | |
1557 | .attrs = cpuhp_cpu_attrs, | |
1558 | .name = "hotplug", | |
1559 | NULL | |
1560 | }; | |
1561 | ||
1562 | static ssize_t show_cpuhp_states(struct device *dev, | |
1563 | struct device_attribute *attr, char *buf) | |
1564 | { | |
1565 | ssize_t cur, res = 0; | |
1566 | int i; | |
1567 | ||
1568 | mutex_lock(&cpuhp_state_mutex); | |
757c989b | 1569 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
98f8cdce TG |
1570 | struct cpuhp_step *sp = cpuhp_get_step(i); |
1571 | ||
1572 | if (sp->name) { | |
1573 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
1574 | buf += cur; | |
1575 | res += cur; | |
1576 | } | |
1577 | } | |
1578 | mutex_unlock(&cpuhp_state_mutex); | |
1579 | return res; | |
1580 | } | |
1581 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
1582 | ||
1583 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
1584 | &dev_attr_states.attr, | |
1585 | NULL | |
1586 | }; | |
1587 | ||
1588 | static struct attribute_group cpuhp_cpu_root_attr_group = { | |
1589 | .attrs = cpuhp_cpu_root_attrs, | |
1590 | .name = "hotplug", | |
1591 | NULL | |
1592 | }; | |
1593 | ||
1594 | static int __init cpuhp_sysfs_init(void) | |
1595 | { | |
1596 | int cpu, ret; | |
1597 | ||
1598 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, | |
1599 | &cpuhp_cpu_root_attr_group); | |
1600 | if (ret) | |
1601 | return ret; | |
1602 | ||
1603 | for_each_possible_cpu(cpu) { | |
1604 | struct device *dev = get_cpu_device(cpu); | |
1605 | ||
1606 | if (!dev) | |
1607 | continue; | |
1608 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
1609 | if (ret) | |
1610 | return ret; | |
1611 | } | |
1612 | return 0; | |
1613 | } | |
1614 | device_initcall(cpuhp_sysfs_init); | |
1615 | #endif | |
1616 | ||
e56b3bc7 LT |
1617 | /* |
1618 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
1619 | * represents all NR_CPUS bits binary values of 1<<nr. | |
1620 | * | |
e0b582ec | 1621 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
1622 | * mask value that has a single bit set only. |
1623 | */ | |
b8d317d1 | 1624 | |
e56b3bc7 | 1625 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 1626 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
1627 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
1628 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
1629 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 1630 | |
e56b3bc7 LT |
1631 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
1632 | ||
1633 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
1634 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
1635 | #if BITS_PER_LONG > 32 | |
1636 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
1637 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
1638 | #endif |
1639 | }; | |
e56b3bc7 | 1640 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
1641 | |
1642 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
1643 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
1644 | |
1645 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 1646 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 1647 | = {CPU_BITS_ALL}; |
b3199c02 | 1648 | #else |
4b804c85 | 1649 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 1650 | #endif |
4b804c85 | 1651 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 1652 | |
4b804c85 RV |
1653 | struct cpumask __cpu_online_mask __read_mostly; |
1654 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 1655 | |
4b804c85 RV |
1656 | struct cpumask __cpu_present_mask __read_mostly; |
1657 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 1658 | |
4b804c85 RV |
1659 | struct cpumask __cpu_active_mask __read_mostly; |
1660 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 1661 | |
3fa41520 RR |
1662 | void init_cpu_present(const struct cpumask *src) |
1663 | { | |
c4c54dd1 | 1664 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
1665 | } |
1666 | ||
1667 | void init_cpu_possible(const struct cpumask *src) | |
1668 | { | |
c4c54dd1 | 1669 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
1670 | } |
1671 | ||
1672 | void init_cpu_online(const struct cpumask *src) | |
1673 | { | |
c4c54dd1 | 1674 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 1675 | } |
cff7d378 TG |
1676 | |
1677 | /* | |
1678 | * Activate the first processor. | |
1679 | */ | |
1680 | void __init boot_cpu_init(void) | |
1681 | { | |
1682 | int cpu = smp_processor_id(); | |
1683 | ||
1684 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
1685 | set_cpu_online(cpu, true); | |
1686 | set_cpu_active(cpu, true); | |
1687 | set_cpu_present(cpu, true); | |
1688 | set_cpu_possible(cpu, true); | |
1689 | } | |
1690 | ||
1691 | /* | |
1692 | * Must be called _AFTER_ setting up the per_cpu areas | |
1693 | */ | |
1694 | void __init boot_cpu_state_init(void) | |
1695 | { | |
1696 | per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE; | |
1697 | } |