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> |
1da177e4 | 23 | |
38498a67 TG |
24 | #include "smpboot.h" |
25 | ||
98a79d6a | 26 | #ifdef CONFIG_SMP |
b3199c02 | 27 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 28 | static DEFINE_MUTEX(cpu_add_remove_lock); |
1da177e4 | 29 | |
79a6cdeb | 30 | /* |
93ae4f97 SB |
31 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
32 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
33 | * The APIs cpu_notifier_register_begin/done() must be used to protect CPU | |
34 | * hotplug callback (un)registration performed using __register_cpu_notifier() | |
35 | * or __unregister_cpu_notifier(). | |
79a6cdeb LJ |
36 | */ |
37 | void cpu_maps_update_begin(void) | |
38 | { | |
39 | mutex_lock(&cpu_add_remove_lock); | |
40 | } | |
93ae4f97 | 41 | EXPORT_SYMBOL(cpu_notifier_register_begin); |
79a6cdeb LJ |
42 | |
43 | void cpu_maps_update_done(void) | |
44 | { | |
45 | mutex_unlock(&cpu_add_remove_lock); | |
46 | } | |
93ae4f97 | 47 | EXPORT_SYMBOL(cpu_notifier_register_done); |
79a6cdeb | 48 | |
5c113fbe | 49 | static RAW_NOTIFIER_HEAD(cpu_chain); |
1da177e4 | 50 | |
e3920fb4 RW |
51 | /* If set, cpu_up and cpu_down will return -EBUSY and do nothing. |
52 | * Should always be manipulated under cpu_add_remove_lock | |
53 | */ | |
54 | static int cpu_hotplug_disabled; | |
55 | ||
79a6cdeb LJ |
56 | #ifdef CONFIG_HOTPLUG_CPU |
57 | ||
d221938c GS |
58 | static struct { |
59 | struct task_struct *active_writer; | |
60 | struct mutex lock; /* Synchronizes accesses to refcount, */ | |
61 | /* | |
62 | * Also blocks the new readers during | |
63 | * an ongoing cpu hotplug operation. | |
64 | */ | |
65 | int refcount; | |
a19423b9 GS |
66 | |
67 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
68 | struct lockdep_map dep_map; | |
69 | #endif | |
31950eb6 LT |
70 | } cpu_hotplug = { |
71 | .active_writer = NULL, | |
72 | .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock), | |
73 | .refcount = 0, | |
a19423b9 GS |
74 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
75 | .dep_map = {.name = "cpu_hotplug.lock" }, | |
76 | #endif | |
31950eb6 | 77 | }; |
d221938c | 78 | |
a19423b9 GS |
79 | /* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */ |
80 | #define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map) | |
81 | #define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map) | |
82 | #define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map) | |
83 | ||
86ef5c9a | 84 | void get_online_cpus(void) |
a9d9baa1 | 85 | { |
d221938c GS |
86 | might_sleep(); |
87 | if (cpu_hotplug.active_writer == current) | |
aa953877 | 88 | return; |
a19423b9 | 89 | cpuhp_lock_acquire_read(); |
d221938c GS |
90 | mutex_lock(&cpu_hotplug.lock); |
91 | cpu_hotplug.refcount++; | |
92 | mutex_unlock(&cpu_hotplug.lock); | |
93 | ||
a9d9baa1 | 94 | } |
86ef5c9a | 95 | EXPORT_SYMBOL_GPL(get_online_cpus); |
90d45d17 | 96 | |
86ef5c9a | 97 | void put_online_cpus(void) |
a9d9baa1 | 98 | { |
d221938c | 99 | if (cpu_hotplug.active_writer == current) |
aa953877 | 100 | return; |
d221938c | 101 | mutex_lock(&cpu_hotplug.lock); |
075663d1 SB |
102 | |
103 | if (WARN_ON(!cpu_hotplug.refcount)) | |
104 | cpu_hotplug.refcount++; /* try to fix things up */ | |
105 | ||
d2ba7e2a ON |
106 | if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer)) |
107 | wake_up_process(cpu_hotplug.active_writer); | |
d221938c | 108 | mutex_unlock(&cpu_hotplug.lock); |
a19423b9 | 109 | cpuhp_lock_release(); |
d221938c | 110 | |
a9d9baa1 | 111 | } |
86ef5c9a | 112 | EXPORT_SYMBOL_GPL(put_online_cpus); |
a9d9baa1 | 113 | |
d221938c GS |
114 | /* |
115 | * This ensures that the hotplug operation can begin only when the | |
116 | * refcount goes to zero. | |
117 | * | |
118 | * Note that during a cpu-hotplug operation, the new readers, if any, | |
119 | * will be blocked by the cpu_hotplug.lock | |
120 | * | |
d2ba7e2a ON |
121 | * Since cpu_hotplug_begin() is always called after invoking |
122 | * cpu_maps_update_begin(), we can be sure that only one writer is active. | |
d221938c GS |
123 | * |
124 | * Note that theoretically, there is a possibility of a livelock: | |
125 | * - Refcount goes to zero, last reader wakes up the sleeping | |
126 | * writer. | |
127 | * - Last reader unlocks the cpu_hotplug.lock. | |
128 | * - A new reader arrives at this moment, bumps up the refcount. | |
129 | * - The writer acquires the cpu_hotplug.lock finds the refcount | |
130 | * non zero and goes to sleep again. | |
131 | * | |
132 | * However, this is very difficult to achieve in practice since | |
86ef5c9a | 133 | * get_online_cpus() not an api which is called all that often. |
d221938c GS |
134 | * |
135 | */ | |
b9d10be7 | 136 | void cpu_hotplug_begin(void) |
d221938c | 137 | { |
d221938c | 138 | cpu_hotplug.active_writer = current; |
d2ba7e2a | 139 | |
a19423b9 | 140 | cpuhp_lock_acquire(); |
d2ba7e2a ON |
141 | for (;;) { |
142 | mutex_lock(&cpu_hotplug.lock); | |
143 | if (likely(!cpu_hotplug.refcount)) | |
144 | break; | |
145 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
d221938c GS |
146 | mutex_unlock(&cpu_hotplug.lock); |
147 | schedule(); | |
d221938c | 148 | } |
d221938c GS |
149 | } |
150 | ||
b9d10be7 | 151 | void cpu_hotplug_done(void) |
d221938c GS |
152 | { |
153 | cpu_hotplug.active_writer = NULL; | |
154 | mutex_unlock(&cpu_hotplug.lock); | |
a19423b9 | 155 | cpuhp_lock_release(); |
d221938c | 156 | } |
79a6cdeb | 157 | |
16e53dbf SB |
158 | /* |
159 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
160 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
161 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
162 | * hotplug path before performing hotplug operations. So acquiring that lock | |
163 | * guarantees mutual exclusion from any currently running hotplug operations. | |
164 | */ | |
165 | void cpu_hotplug_disable(void) | |
166 | { | |
167 | cpu_maps_update_begin(); | |
168 | cpu_hotplug_disabled = 1; | |
169 | cpu_maps_update_done(); | |
170 | } | |
171 | ||
172 | void cpu_hotplug_enable(void) | |
173 | { | |
174 | cpu_maps_update_begin(); | |
175 | cpu_hotplug_disabled = 0; | |
176 | cpu_maps_update_done(); | |
177 | } | |
178 | ||
b9d10be7 | 179 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 180 | |
1da177e4 | 181 | /* Need to know about CPUs going up/down? */ |
f7b16c10 | 182 | int __ref register_cpu_notifier(struct notifier_block *nb) |
1da177e4 | 183 | { |
bd5349cf | 184 | int ret; |
d221938c | 185 | cpu_maps_update_begin(); |
bd5349cf | 186 | ret = raw_notifier_chain_register(&cpu_chain, nb); |
d221938c | 187 | cpu_maps_update_done(); |
bd5349cf | 188 | return ret; |
1da177e4 | 189 | } |
65edc68c | 190 | |
93ae4f97 SB |
191 | int __ref __register_cpu_notifier(struct notifier_block *nb) |
192 | { | |
193 | return raw_notifier_chain_register(&cpu_chain, nb); | |
194 | } | |
195 | ||
e9fb7631 AM |
196 | static int __cpu_notify(unsigned long val, void *v, int nr_to_call, |
197 | int *nr_calls) | |
198 | { | |
e6bde73b AM |
199 | int ret; |
200 | ||
201 | ret = __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call, | |
e9fb7631 | 202 | nr_calls); |
e6bde73b AM |
203 | |
204 | return notifier_to_errno(ret); | |
e9fb7631 AM |
205 | } |
206 | ||
207 | static int cpu_notify(unsigned long val, void *v) | |
208 | { | |
209 | return __cpu_notify(val, v, -1, NULL); | |
210 | } | |
211 | ||
00b9b0af LT |
212 | #ifdef CONFIG_HOTPLUG_CPU |
213 | ||
e9fb7631 AM |
214 | static void cpu_notify_nofail(unsigned long val, void *v) |
215 | { | |
00b9b0af | 216 | BUG_ON(cpu_notify(val, v)); |
e9fb7631 | 217 | } |
1da177e4 | 218 | EXPORT_SYMBOL(register_cpu_notifier); |
93ae4f97 | 219 | EXPORT_SYMBOL(__register_cpu_notifier); |
1da177e4 | 220 | |
9647155f | 221 | void __ref unregister_cpu_notifier(struct notifier_block *nb) |
1da177e4 | 222 | { |
d221938c | 223 | cpu_maps_update_begin(); |
bd5349cf | 224 | raw_notifier_chain_unregister(&cpu_chain, nb); |
d221938c | 225 | cpu_maps_update_done(); |
1da177e4 LT |
226 | } |
227 | EXPORT_SYMBOL(unregister_cpu_notifier); | |
228 | ||
93ae4f97 SB |
229 | void __ref __unregister_cpu_notifier(struct notifier_block *nb) |
230 | { | |
231 | raw_notifier_chain_unregister(&cpu_chain, nb); | |
232 | } | |
233 | EXPORT_SYMBOL(__unregister_cpu_notifier); | |
234 | ||
e4cc2f87 AV |
235 | /** |
236 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
237 | * @cpu: a CPU id | |
238 | * | |
239 | * This function walks all processes, finds a valid mm struct for each one and | |
240 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
241 | * trivial, there are various non-obvious corner cases, which this function | |
242 | * tries to solve in a safe manner. | |
243 | * | |
244 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
245 | * be called only for an already offlined CPU. | |
246 | */ | |
cb79295e AV |
247 | void clear_tasks_mm_cpumask(int cpu) |
248 | { | |
249 | struct task_struct *p; | |
250 | ||
251 | /* | |
252 | * This function is called after the cpu is taken down and marked | |
253 | * offline, so its not like new tasks will ever get this cpu set in | |
254 | * their mm mask. -- Peter Zijlstra | |
255 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
256 | * full-fledged tasklist_lock. | |
257 | */ | |
e4cc2f87 | 258 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
259 | rcu_read_lock(); |
260 | for_each_process(p) { | |
261 | struct task_struct *t; | |
262 | ||
e4cc2f87 AV |
263 | /* |
264 | * Main thread might exit, but other threads may still have | |
265 | * a valid mm. Find one. | |
266 | */ | |
cb79295e AV |
267 | t = find_lock_task_mm(p); |
268 | if (!t) | |
269 | continue; | |
270 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
271 | task_unlock(t); | |
272 | } | |
273 | rcu_read_unlock(); | |
274 | } | |
275 | ||
1da177e4 LT |
276 | static inline void check_for_tasks(int cpu) |
277 | { | |
278 | struct task_struct *p; | |
6fac4829 | 279 | cputime_t utime, stime; |
1da177e4 LT |
280 | |
281 | write_lock_irq(&tasklist_lock); | |
282 | for_each_process(p) { | |
6fac4829 | 283 | task_cputime(p, &utime, &stime); |
11854247 | 284 | if (task_cpu(p) == cpu && p->state == TASK_RUNNING && |
6fac4829 | 285 | (utime || stime)) |
84117da5 | 286 | pr_warn("Task %s (pid = %d) is on cpu %d (state = %ld, flags = %x)\n", |
9d3cfc4c FP |
287 | p->comm, task_pid_nr(p), cpu, |
288 | p->state, p->flags); | |
1da177e4 LT |
289 | } |
290 | write_unlock_irq(&tasklist_lock); | |
291 | } | |
292 | ||
db912f96 AK |
293 | struct take_cpu_down_param { |
294 | unsigned long mod; | |
295 | void *hcpu; | |
296 | }; | |
297 | ||
1da177e4 | 298 | /* Take this CPU down. */ |
514a20a5 | 299 | static int __ref take_cpu_down(void *_param) |
1da177e4 | 300 | { |
db912f96 | 301 | struct take_cpu_down_param *param = _param; |
1da177e4 LT |
302 | int err; |
303 | ||
1da177e4 LT |
304 | /* Ensure this CPU doesn't handle any more interrupts. */ |
305 | err = __cpu_disable(); | |
306 | if (err < 0) | |
f3705136 | 307 | return err; |
1da177e4 | 308 | |
e9fb7631 | 309 | cpu_notify(CPU_DYING | param->mod, param->hcpu); |
14e568e7 TG |
310 | /* Park the stopper thread */ |
311 | kthread_park(current); | |
f3705136 | 312 | return 0; |
1da177e4 LT |
313 | } |
314 | ||
e3920fb4 | 315 | /* Requires cpu_add_remove_lock to be held */ |
514a20a5 | 316 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) |
1da177e4 | 317 | { |
e7407dcc | 318 | int err, nr_calls = 0; |
e7407dcc | 319 | void *hcpu = (void *)(long)cpu; |
8bb78442 | 320 | unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; |
db912f96 AK |
321 | struct take_cpu_down_param tcd_param = { |
322 | .mod = mod, | |
323 | .hcpu = hcpu, | |
324 | }; | |
1da177e4 | 325 | |
e3920fb4 RW |
326 | if (num_online_cpus() == 1) |
327 | return -EBUSY; | |
1da177e4 | 328 | |
e3920fb4 RW |
329 | if (!cpu_online(cpu)) |
330 | return -EINVAL; | |
1da177e4 | 331 | |
d221938c | 332 | cpu_hotplug_begin(); |
4d51985e | 333 | |
e9fb7631 | 334 | err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls); |
e6bde73b | 335 | if (err) { |
a0d8cdb6 | 336 | nr_calls--; |
e9fb7631 | 337 | __cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL); |
84117da5 FF |
338 | pr_warn("%s: attempt to take down CPU %u failed\n", |
339 | __func__, cpu); | |
baaca49f | 340 | goto out_release; |
1da177e4 LT |
341 | } |
342 | ||
6acce3ef PZ |
343 | /* |
344 | * By now we've cleared cpu_active_mask, wait for all preempt-disabled | |
345 | * and RCU users of this state to go away such that all new such users | |
346 | * will observe it. | |
347 | * | |
348 | * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might | |
349 | * not imply sync_sched(), so explicitly call both. | |
106dd5af M |
350 | * |
351 | * Do sync before park smpboot threads to take care the rcu boost case. | |
6acce3ef PZ |
352 | */ |
353 | #ifdef CONFIG_PREEMPT | |
354 | synchronize_sched(); | |
355 | #endif | |
356 | synchronize_rcu(); | |
357 | ||
106dd5af M |
358 | smpboot_park_threads(cpu); |
359 | ||
6acce3ef PZ |
360 | /* |
361 | * So now all preempt/rcu users must observe !cpu_active(). | |
362 | */ | |
363 | ||
e0b582ec | 364 | err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu)); |
04321587 | 365 | if (err) { |
1da177e4 | 366 | /* CPU didn't die: tell everyone. Can't complain. */ |
f97f8f06 | 367 | smpboot_unpark_threads(cpu); |
e9fb7631 | 368 | cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu); |
6a1bdc1b | 369 | goto out_release; |
8fa1d7d3 | 370 | } |
04321587 | 371 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 372 | |
48c5ccae PZ |
373 | /* |
374 | * The migration_call() CPU_DYING callback will have removed all | |
375 | * runnable tasks from the cpu, there's only the idle task left now | |
376 | * that the migration thread is done doing the stop_machine thing. | |
51a96c77 PZ |
377 | * |
378 | * Wait for the stop thread to go away. | |
48c5ccae | 379 | */ |
51a96c77 PZ |
380 | while (!idle_cpu(cpu)) |
381 | cpu_relax(); | |
1da177e4 LT |
382 | |
383 | /* This actually kills the CPU. */ | |
384 | __cpu_die(cpu); | |
385 | ||
1da177e4 | 386 | /* CPU is completely dead: tell everyone. Too late to complain. */ |
e9fb7631 | 387 | cpu_notify_nofail(CPU_DEAD | mod, hcpu); |
1da177e4 LT |
388 | |
389 | check_for_tasks(cpu); | |
390 | ||
baaca49f | 391 | out_release: |
d221938c | 392 | cpu_hotplug_done(); |
e9fb7631 AM |
393 | if (!err) |
394 | cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu); | |
e3920fb4 RW |
395 | return err; |
396 | } | |
397 | ||
514a20a5 | 398 | int __ref cpu_down(unsigned int cpu) |
e3920fb4 | 399 | { |
9ea09af3 | 400 | int err; |
e3920fb4 | 401 | |
d221938c | 402 | cpu_maps_update_begin(); |
e761b772 MK |
403 | |
404 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 405 | err = -EBUSY; |
e761b772 MK |
406 | goto out; |
407 | } | |
408 | ||
e761b772 | 409 | err = _cpu_down(cpu, 0); |
e3920fb4 | 410 | |
e761b772 | 411 | out: |
d221938c | 412 | cpu_maps_update_done(); |
1da177e4 LT |
413 | return err; |
414 | } | |
b62b8ef9 | 415 | EXPORT_SYMBOL(cpu_down); |
1da177e4 LT |
416 | #endif /*CONFIG_HOTPLUG_CPU*/ |
417 | ||
e3920fb4 | 418 | /* Requires cpu_add_remove_lock to be held */ |
0db0628d | 419 | static int _cpu_up(unsigned int cpu, int tasks_frozen) |
1da177e4 | 420 | { |
baaca49f | 421 | int ret, nr_calls = 0; |
1da177e4 | 422 | void *hcpu = (void *)(long)cpu; |
8bb78442 | 423 | unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; |
3bb5d2ee | 424 | struct task_struct *idle; |
1da177e4 | 425 | |
d221938c | 426 | cpu_hotplug_begin(); |
38498a67 | 427 | |
5e5041f3 YI |
428 | if (cpu_online(cpu) || !cpu_present(cpu)) { |
429 | ret = -EINVAL; | |
430 | goto out; | |
431 | } | |
432 | ||
3bb5d2ee SS |
433 | idle = idle_thread_get(cpu); |
434 | if (IS_ERR(idle)) { | |
435 | ret = PTR_ERR(idle); | |
38498a67 | 436 | goto out; |
3bb5d2ee | 437 | } |
38498a67 | 438 | |
f97f8f06 TG |
439 | ret = smpboot_create_threads(cpu); |
440 | if (ret) | |
441 | goto out; | |
442 | ||
e9fb7631 | 443 | ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls); |
e6bde73b | 444 | if (ret) { |
a0d8cdb6 | 445 | nr_calls--; |
84117da5 FF |
446 | pr_warn("%s: attempt to bring up CPU %u failed\n", |
447 | __func__, cpu); | |
1da177e4 LT |
448 | goto out_notify; |
449 | } | |
450 | ||
451 | /* Arch-specific enabling code. */ | |
3bb5d2ee | 452 | ret = __cpu_up(cpu, idle); |
1da177e4 LT |
453 | if (ret != 0) |
454 | goto out_notify; | |
6978c705 | 455 | BUG_ON(!cpu_online(cpu)); |
1da177e4 | 456 | |
f97f8f06 TG |
457 | /* Wake the per cpu threads */ |
458 | smpboot_unpark_threads(cpu); | |
459 | ||
1da177e4 | 460 | /* Now call notifier in preparation. */ |
e9fb7631 | 461 | cpu_notify(CPU_ONLINE | mod, hcpu); |
1da177e4 LT |
462 | |
463 | out_notify: | |
464 | if (ret != 0) | |
e9fb7631 | 465 | __cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL); |
38498a67 | 466 | out: |
d221938c | 467 | cpu_hotplug_done(); |
e3920fb4 RW |
468 | |
469 | return ret; | |
470 | } | |
471 | ||
0db0628d | 472 | int cpu_up(unsigned int cpu) |
e3920fb4 RW |
473 | { |
474 | int err = 0; | |
cf23422b | 475 | |
e0b582ec | 476 | if (!cpu_possible(cpu)) { |
84117da5 FF |
477 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
478 | cpu); | |
87d5e023 | 479 | #if defined(CONFIG_IA64) |
84117da5 | 480 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
481 | #endif |
482 | return -EINVAL; | |
483 | } | |
e3920fb4 | 484 | |
01b0f197 TK |
485 | err = try_online_node(cpu_to_node(cpu)); |
486 | if (err) | |
487 | return err; | |
cf23422b | 488 | |
d221938c | 489 | cpu_maps_update_begin(); |
e761b772 MK |
490 | |
491 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 492 | err = -EBUSY; |
e761b772 MK |
493 | goto out; |
494 | } | |
495 | ||
496 | err = _cpu_up(cpu, 0); | |
497 | ||
e761b772 | 498 | out: |
d221938c | 499 | cpu_maps_update_done(); |
e3920fb4 RW |
500 | return err; |
501 | } | |
a513f6ba | 502 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 503 | |
f3de4be9 | 504 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 505 | static cpumask_var_t frozen_cpus; |
e3920fb4 RW |
506 | |
507 | int disable_nonboot_cpus(void) | |
508 | { | |
e9a5f426 | 509 | int cpu, first_cpu, error = 0; |
e3920fb4 | 510 | |
d221938c | 511 | cpu_maps_update_begin(); |
e0b582ec | 512 | first_cpu = cpumask_first(cpu_online_mask); |
9ee349ad XF |
513 | /* |
514 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
515 | * with the userspace trying to use the CPU hotplug at the same time |
516 | */ | |
e0b582ec | 517 | cpumask_clear(frozen_cpus); |
6ad4c188 | 518 | |
84117da5 | 519 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 RW |
520 | for_each_online_cpu(cpu) { |
521 | if (cpu == first_cpu) | |
522 | continue; | |
8bb78442 | 523 | error = _cpu_down(cpu, 1); |
feae3203 | 524 | if (!error) |
e0b582ec | 525 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 526 | else { |
84117da5 | 527 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
528 | break; |
529 | } | |
530 | } | |
86886e55 | 531 | |
e3920fb4 RW |
532 | if (!error) { |
533 | BUG_ON(num_online_cpus() > 1); | |
534 | /* Make sure the CPUs won't be enabled by someone else */ | |
535 | cpu_hotplug_disabled = 1; | |
536 | } else { | |
84117da5 | 537 | pr_err("Non-boot CPUs are not disabled\n"); |
e3920fb4 | 538 | } |
d221938c | 539 | cpu_maps_update_done(); |
e3920fb4 RW |
540 | return error; |
541 | } | |
542 | ||
d0af9eed SS |
543 | void __weak arch_enable_nonboot_cpus_begin(void) |
544 | { | |
545 | } | |
546 | ||
547 | void __weak arch_enable_nonboot_cpus_end(void) | |
548 | { | |
549 | } | |
550 | ||
fa7303e2 | 551 | void __ref enable_nonboot_cpus(void) |
e3920fb4 RW |
552 | { |
553 | int cpu, error; | |
554 | ||
555 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 556 | cpu_maps_update_begin(); |
e3920fb4 | 557 | cpu_hotplug_disabled = 0; |
e0b582ec | 558 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 559 | goto out; |
e3920fb4 | 560 | |
84117da5 | 561 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
562 | |
563 | arch_enable_nonboot_cpus_begin(); | |
564 | ||
e0b582ec | 565 | for_each_cpu(cpu, frozen_cpus) { |
8bb78442 | 566 | error = _cpu_up(cpu, 1); |
e3920fb4 | 567 | if (!error) { |
84117da5 | 568 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
569 | continue; |
570 | } | |
84117da5 | 571 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 572 | } |
d0af9eed SS |
573 | |
574 | arch_enable_nonboot_cpus_end(); | |
575 | ||
e0b582ec | 576 | cpumask_clear(frozen_cpus); |
1d64b9cb | 577 | out: |
d221938c | 578 | cpu_maps_update_done(); |
1da177e4 | 579 | } |
e0b582ec | 580 | |
d7268a31 | 581 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
582 | { |
583 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
584 | return -ENOMEM; | |
585 | return 0; | |
586 | } | |
587 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 588 | |
79cfbdfa SB |
589 | /* |
590 | * When callbacks for CPU hotplug notifications are being executed, we must | |
591 | * ensure that the state of the system with respect to the tasks being frozen | |
592 | * or not, as reported by the notification, remains unchanged *throughout the | |
593 | * duration* of the execution of the callbacks. | |
594 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
595 | * | |
596 | * This synchronization is implemented by mutually excluding regular CPU | |
597 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
598 | * Hibernate notifications. | |
599 | */ | |
600 | static int | |
601 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
602 | unsigned long action, void *ptr) | |
603 | { | |
604 | switch (action) { | |
605 | ||
606 | case PM_SUSPEND_PREPARE: | |
607 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 608 | cpu_hotplug_disable(); |
79cfbdfa SB |
609 | break; |
610 | ||
611 | case PM_POST_SUSPEND: | |
612 | case PM_POST_HIBERNATION: | |
16e53dbf | 613 | cpu_hotplug_enable(); |
79cfbdfa SB |
614 | break; |
615 | ||
616 | default: | |
617 | return NOTIFY_DONE; | |
618 | } | |
619 | ||
620 | return NOTIFY_OK; | |
621 | } | |
622 | ||
623 | ||
d7268a31 | 624 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 625 | { |
6e32d479 FY |
626 | /* |
627 | * cpu_hotplug_pm_callback has higher priority than x86 | |
628 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
629 | * to disable cpu hotplug to avoid cpu hotplug race. | |
630 | */ | |
79cfbdfa SB |
631 | pm_notifier(cpu_hotplug_pm_callback, 0); |
632 | return 0; | |
633 | } | |
634 | core_initcall(cpu_hotplug_pm_sync_init); | |
635 | ||
f3de4be9 | 636 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 637 | |
e545a614 MS |
638 | /** |
639 | * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers | |
640 | * @cpu: cpu that just started | |
641 | * | |
642 | * This function calls the cpu_chain notifiers with CPU_STARTING. | |
643 | * It must be called by the arch code on the new cpu, before the new cpu | |
644 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
645 | */ | |
0db0628d | 646 | void notify_cpu_starting(unsigned int cpu) |
e545a614 MS |
647 | { |
648 | unsigned long val = CPU_STARTING; | |
649 | ||
650 | #ifdef CONFIG_PM_SLEEP_SMP | |
e0b582ec | 651 | if (frozen_cpus != NULL && cpumask_test_cpu(cpu, frozen_cpus)) |
e545a614 MS |
652 | val = CPU_STARTING_FROZEN; |
653 | #endif /* CONFIG_PM_SLEEP_SMP */ | |
e9fb7631 | 654 | cpu_notify(val, (void *)(long)cpu); |
e545a614 MS |
655 | } |
656 | ||
68f4f1ec | 657 | #endif /* CONFIG_SMP */ |
b8d317d1 | 658 | |
e56b3bc7 LT |
659 | /* |
660 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
661 | * represents all NR_CPUS bits binary values of 1<<nr. | |
662 | * | |
e0b582ec | 663 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
664 | * mask value that has a single bit set only. |
665 | */ | |
b8d317d1 | 666 | |
e56b3bc7 | 667 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 668 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
669 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
670 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
671 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 672 | |
e56b3bc7 LT |
673 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
674 | ||
675 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
676 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
677 | #if BITS_PER_LONG > 32 | |
678 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
679 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
680 | #endif |
681 | }; | |
e56b3bc7 | 682 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
683 | |
684 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
685 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
686 | |
687 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
688 | static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly | |
689 | = CPU_BITS_ALL; | |
690 | #else | |
691 | static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly; | |
692 | #endif | |
693 | const struct cpumask *const cpu_possible_mask = to_cpumask(cpu_possible_bits); | |
694 | EXPORT_SYMBOL(cpu_possible_mask); | |
695 | ||
696 | static DECLARE_BITMAP(cpu_online_bits, CONFIG_NR_CPUS) __read_mostly; | |
697 | const struct cpumask *const cpu_online_mask = to_cpumask(cpu_online_bits); | |
698 | EXPORT_SYMBOL(cpu_online_mask); | |
699 | ||
700 | static DECLARE_BITMAP(cpu_present_bits, CONFIG_NR_CPUS) __read_mostly; | |
701 | const struct cpumask *const cpu_present_mask = to_cpumask(cpu_present_bits); | |
702 | EXPORT_SYMBOL(cpu_present_mask); | |
703 | ||
704 | static DECLARE_BITMAP(cpu_active_bits, CONFIG_NR_CPUS) __read_mostly; | |
705 | const struct cpumask *const cpu_active_mask = to_cpumask(cpu_active_bits); | |
706 | EXPORT_SYMBOL(cpu_active_mask); | |
3fa41520 RR |
707 | |
708 | void set_cpu_possible(unsigned int cpu, bool possible) | |
709 | { | |
710 | if (possible) | |
711 | cpumask_set_cpu(cpu, to_cpumask(cpu_possible_bits)); | |
712 | else | |
713 | cpumask_clear_cpu(cpu, to_cpumask(cpu_possible_bits)); | |
714 | } | |
715 | ||
716 | void set_cpu_present(unsigned int cpu, bool present) | |
717 | { | |
718 | if (present) | |
719 | cpumask_set_cpu(cpu, to_cpumask(cpu_present_bits)); | |
720 | else | |
721 | cpumask_clear_cpu(cpu, to_cpumask(cpu_present_bits)); | |
722 | } | |
723 | ||
724 | void set_cpu_online(unsigned int cpu, bool online) | |
725 | { | |
6acbfb96 | 726 | if (online) { |
3fa41520 | 727 | cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits)); |
6acbfb96 LJ |
728 | cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits)); |
729 | } else { | |
3fa41520 | 730 | cpumask_clear_cpu(cpu, to_cpumask(cpu_online_bits)); |
6acbfb96 | 731 | } |
3fa41520 RR |
732 | } |
733 | ||
734 | void set_cpu_active(unsigned int cpu, bool active) | |
735 | { | |
736 | if (active) | |
737 | cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits)); | |
738 | else | |
739 | cpumask_clear_cpu(cpu, to_cpumask(cpu_active_bits)); | |
740 | } | |
741 | ||
742 | void init_cpu_present(const struct cpumask *src) | |
743 | { | |
744 | cpumask_copy(to_cpumask(cpu_present_bits), src); | |
745 | } | |
746 | ||
747 | void init_cpu_possible(const struct cpumask *src) | |
748 | { | |
749 | cpumask_copy(to_cpumask(cpu_possible_bits), src); | |
750 | } | |
751 | ||
752 | void init_cpu_online(const struct cpumask *src) | |
753 | { | |
754 | cpumask_copy(to_cpumask(cpu_online_bits), src); | |
755 | } |