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> |
1da177e4 | 22 | |
38498a67 TG |
23 | #include "smpboot.h" |
24 | ||
98a79d6a | 25 | #ifdef CONFIG_SMP |
b3199c02 | 26 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 27 | static DEFINE_MUTEX(cpu_add_remove_lock); |
1da177e4 | 28 | |
79a6cdeb LJ |
29 | /* |
30 | * The following two API's must be used when attempting | |
31 | * to serialize the updates to cpu_online_mask, cpu_present_mask. | |
32 | */ | |
33 | void cpu_maps_update_begin(void) | |
34 | { | |
35 | mutex_lock(&cpu_add_remove_lock); | |
36 | } | |
37 | ||
38 | void cpu_maps_update_done(void) | |
39 | { | |
40 | mutex_unlock(&cpu_add_remove_lock); | |
41 | } | |
42 | ||
5c113fbe | 43 | static RAW_NOTIFIER_HEAD(cpu_chain); |
1da177e4 | 44 | |
e3920fb4 RW |
45 | /* If set, cpu_up and cpu_down will return -EBUSY and do nothing. |
46 | * Should always be manipulated under cpu_add_remove_lock | |
47 | */ | |
48 | static int cpu_hotplug_disabled; | |
49 | ||
79a6cdeb LJ |
50 | #ifdef CONFIG_HOTPLUG_CPU |
51 | ||
d221938c GS |
52 | static struct { |
53 | struct task_struct *active_writer; | |
54 | struct mutex lock; /* Synchronizes accesses to refcount, */ | |
55 | /* | |
56 | * Also blocks the new readers during | |
57 | * an ongoing cpu hotplug operation. | |
58 | */ | |
59 | int refcount; | |
31950eb6 LT |
60 | } cpu_hotplug = { |
61 | .active_writer = NULL, | |
62 | .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock), | |
63 | .refcount = 0, | |
64 | }; | |
d221938c | 65 | |
86ef5c9a | 66 | void get_online_cpus(void) |
a9d9baa1 | 67 | { |
d221938c GS |
68 | might_sleep(); |
69 | if (cpu_hotplug.active_writer == current) | |
aa953877 | 70 | return; |
d221938c GS |
71 | mutex_lock(&cpu_hotplug.lock); |
72 | cpu_hotplug.refcount++; | |
73 | mutex_unlock(&cpu_hotplug.lock); | |
74 | ||
a9d9baa1 | 75 | } |
86ef5c9a | 76 | EXPORT_SYMBOL_GPL(get_online_cpus); |
90d45d17 | 77 | |
86ef5c9a | 78 | void put_online_cpus(void) |
a9d9baa1 | 79 | { |
d221938c | 80 | if (cpu_hotplug.active_writer == current) |
aa953877 | 81 | return; |
d221938c | 82 | mutex_lock(&cpu_hotplug.lock); |
075663d1 SB |
83 | |
84 | if (WARN_ON(!cpu_hotplug.refcount)) | |
85 | cpu_hotplug.refcount++; /* try to fix things up */ | |
86 | ||
d2ba7e2a ON |
87 | if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer)) |
88 | wake_up_process(cpu_hotplug.active_writer); | |
d221938c GS |
89 | mutex_unlock(&cpu_hotplug.lock); |
90 | ||
a9d9baa1 | 91 | } |
86ef5c9a | 92 | EXPORT_SYMBOL_GPL(put_online_cpus); |
a9d9baa1 | 93 | |
d221938c GS |
94 | /* |
95 | * This ensures that the hotplug operation can begin only when the | |
96 | * refcount goes to zero. | |
97 | * | |
98 | * Note that during a cpu-hotplug operation, the new readers, if any, | |
99 | * will be blocked by the cpu_hotplug.lock | |
100 | * | |
d2ba7e2a ON |
101 | * Since cpu_hotplug_begin() is always called after invoking |
102 | * cpu_maps_update_begin(), we can be sure that only one writer is active. | |
d221938c GS |
103 | * |
104 | * Note that theoretically, there is a possibility of a livelock: | |
105 | * - Refcount goes to zero, last reader wakes up the sleeping | |
106 | * writer. | |
107 | * - Last reader unlocks the cpu_hotplug.lock. | |
108 | * - A new reader arrives at this moment, bumps up the refcount. | |
109 | * - The writer acquires the cpu_hotplug.lock finds the refcount | |
110 | * non zero and goes to sleep again. | |
111 | * | |
112 | * However, this is very difficult to achieve in practice since | |
86ef5c9a | 113 | * get_online_cpus() not an api which is called all that often. |
d221938c GS |
114 | * |
115 | */ | |
b9d10be7 | 116 | void cpu_hotplug_begin(void) |
d221938c | 117 | { |
d221938c | 118 | cpu_hotplug.active_writer = current; |
d2ba7e2a ON |
119 | |
120 | for (;;) { | |
121 | mutex_lock(&cpu_hotplug.lock); | |
122 | if (likely(!cpu_hotplug.refcount)) | |
123 | break; | |
124 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
d221938c GS |
125 | mutex_unlock(&cpu_hotplug.lock); |
126 | schedule(); | |
d221938c | 127 | } |
d221938c GS |
128 | } |
129 | ||
b9d10be7 | 130 | void cpu_hotplug_done(void) |
d221938c GS |
131 | { |
132 | cpu_hotplug.active_writer = NULL; | |
133 | mutex_unlock(&cpu_hotplug.lock); | |
134 | } | |
79a6cdeb | 135 | |
16e53dbf SB |
136 | /* |
137 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
138 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
139 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
140 | * hotplug path before performing hotplug operations. So acquiring that lock | |
141 | * guarantees mutual exclusion from any currently running hotplug operations. | |
142 | */ | |
143 | void cpu_hotplug_disable(void) | |
144 | { | |
145 | cpu_maps_update_begin(); | |
146 | cpu_hotplug_disabled = 1; | |
147 | cpu_maps_update_done(); | |
148 | } | |
149 | ||
150 | void cpu_hotplug_enable(void) | |
151 | { | |
152 | cpu_maps_update_begin(); | |
153 | cpu_hotplug_disabled = 0; | |
154 | cpu_maps_update_done(); | |
155 | } | |
156 | ||
b9d10be7 | 157 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 158 | |
1da177e4 | 159 | /* Need to know about CPUs going up/down? */ |
f7b16c10 | 160 | int __ref register_cpu_notifier(struct notifier_block *nb) |
1da177e4 | 161 | { |
bd5349cf | 162 | int ret; |
d221938c | 163 | cpu_maps_update_begin(); |
bd5349cf | 164 | ret = raw_notifier_chain_register(&cpu_chain, nb); |
d221938c | 165 | cpu_maps_update_done(); |
bd5349cf | 166 | return ret; |
1da177e4 | 167 | } |
65edc68c | 168 | |
e9fb7631 AM |
169 | static int __cpu_notify(unsigned long val, void *v, int nr_to_call, |
170 | int *nr_calls) | |
171 | { | |
e6bde73b AM |
172 | int ret; |
173 | ||
174 | ret = __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call, | |
e9fb7631 | 175 | nr_calls); |
e6bde73b AM |
176 | |
177 | return notifier_to_errno(ret); | |
e9fb7631 AM |
178 | } |
179 | ||
180 | static int cpu_notify(unsigned long val, void *v) | |
181 | { | |
182 | return __cpu_notify(val, v, -1, NULL); | |
183 | } | |
184 | ||
00b9b0af LT |
185 | #ifdef CONFIG_HOTPLUG_CPU |
186 | ||
e9fb7631 AM |
187 | static void cpu_notify_nofail(unsigned long val, void *v) |
188 | { | |
00b9b0af | 189 | BUG_ON(cpu_notify(val, v)); |
e9fb7631 | 190 | } |
1da177e4 LT |
191 | EXPORT_SYMBOL(register_cpu_notifier); |
192 | ||
9647155f | 193 | void __ref unregister_cpu_notifier(struct notifier_block *nb) |
1da177e4 | 194 | { |
d221938c | 195 | cpu_maps_update_begin(); |
bd5349cf | 196 | raw_notifier_chain_unregister(&cpu_chain, nb); |
d221938c | 197 | cpu_maps_update_done(); |
1da177e4 LT |
198 | } |
199 | EXPORT_SYMBOL(unregister_cpu_notifier); | |
200 | ||
e4cc2f87 AV |
201 | /** |
202 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
203 | * @cpu: a CPU id | |
204 | * | |
205 | * This function walks all processes, finds a valid mm struct for each one and | |
206 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
207 | * trivial, there are various non-obvious corner cases, which this function | |
208 | * tries to solve in a safe manner. | |
209 | * | |
210 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
211 | * be called only for an already offlined CPU. | |
212 | */ | |
cb79295e AV |
213 | void clear_tasks_mm_cpumask(int cpu) |
214 | { | |
215 | struct task_struct *p; | |
216 | ||
217 | /* | |
218 | * This function is called after the cpu is taken down and marked | |
219 | * offline, so its not like new tasks will ever get this cpu set in | |
220 | * their mm mask. -- Peter Zijlstra | |
221 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
222 | * full-fledged tasklist_lock. | |
223 | */ | |
e4cc2f87 | 224 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
225 | rcu_read_lock(); |
226 | for_each_process(p) { | |
227 | struct task_struct *t; | |
228 | ||
e4cc2f87 AV |
229 | /* |
230 | * Main thread might exit, but other threads may still have | |
231 | * a valid mm. Find one. | |
232 | */ | |
cb79295e AV |
233 | t = find_lock_task_mm(p); |
234 | if (!t) | |
235 | continue; | |
236 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
237 | task_unlock(t); | |
238 | } | |
239 | rcu_read_unlock(); | |
240 | } | |
241 | ||
1da177e4 LT |
242 | static inline void check_for_tasks(int cpu) |
243 | { | |
244 | struct task_struct *p; | |
6fac4829 | 245 | cputime_t utime, stime; |
1da177e4 LT |
246 | |
247 | write_lock_irq(&tasklist_lock); | |
248 | for_each_process(p) { | |
6fac4829 | 249 | task_cputime(p, &utime, &stime); |
11854247 | 250 | if (task_cpu(p) == cpu && p->state == TASK_RUNNING && |
6fac4829 | 251 | (utime || stime)) |
9d3cfc4c FP |
252 | printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d " |
253 | "(state = %ld, flags = %x)\n", | |
254 | p->comm, task_pid_nr(p), cpu, | |
255 | p->state, p->flags); | |
1da177e4 LT |
256 | } |
257 | write_unlock_irq(&tasklist_lock); | |
258 | } | |
259 | ||
db912f96 AK |
260 | struct take_cpu_down_param { |
261 | unsigned long mod; | |
262 | void *hcpu; | |
263 | }; | |
264 | ||
1da177e4 | 265 | /* Take this CPU down. */ |
514a20a5 | 266 | static int __ref take_cpu_down(void *_param) |
1da177e4 | 267 | { |
db912f96 | 268 | struct take_cpu_down_param *param = _param; |
1da177e4 LT |
269 | int err; |
270 | ||
1da177e4 LT |
271 | /* Ensure this CPU doesn't handle any more interrupts. */ |
272 | err = __cpu_disable(); | |
273 | if (err < 0) | |
f3705136 | 274 | return err; |
1da177e4 | 275 | |
e9fb7631 | 276 | cpu_notify(CPU_DYING | param->mod, param->hcpu); |
14e568e7 TG |
277 | /* Park the stopper thread */ |
278 | kthread_park(current); | |
f3705136 | 279 | return 0; |
1da177e4 LT |
280 | } |
281 | ||
e3920fb4 | 282 | /* Requires cpu_add_remove_lock to be held */ |
514a20a5 | 283 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) |
1da177e4 | 284 | { |
e7407dcc | 285 | int err, nr_calls = 0; |
e7407dcc | 286 | void *hcpu = (void *)(long)cpu; |
8bb78442 | 287 | unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; |
db912f96 AK |
288 | struct take_cpu_down_param tcd_param = { |
289 | .mod = mod, | |
290 | .hcpu = hcpu, | |
291 | }; | |
1da177e4 | 292 | |
e3920fb4 RW |
293 | if (num_online_cpus() == 1) |
294 | return -EBUSY; | |
1da177e4 | 295 | |
e3920fb4 RW |
296 | if (!cpu_online(cpu)) |
297 | return -EINVAL; | |
1da177e4 | 298 | |
d221938c | 299 | cpu_hotplug_begin(); |
4d51985e | 300 | |
e9fb7631 | 301 | err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls); |
e6bde73b | 302 | if (err) { |
a0d8cdb6 | 303 | nr_calls--; |
e9fb7631 | 304 | __cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL); |
1da177e4 | 305 | printk("%s: attempt to take down CPU %u failed\n", |
af1f16d0 | 306 | __func__, cpu); |
baaca49f | 307 | goto out_release; |
1da177e4 | 308 | } |
f97f8f06 | 309 | smpboot_park_threads(cpu); |
1da177e4 | 310 | |
6acce3ef PZ |
311 | /* |
312 | * By now we've cleared cpu_active_mask, wait for all preempt-disabled | |
313 | * and RCU users of this state to go away such that all new such users | |
314 | * will observe it. | |
315 | * | |
316 | * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might | |
317 | * not imply sync_sched(), so explicitly call both. | |
318 | */ | |
319 | #ifdef CONFIG_PREEMPT | |
320 | synchronize_sched(); | |
321 | #endif | |
322 | synchronize_rcu(); | |
323 | ||
324 | /* | |
325 | * So now all preempt/rcu users must observe !cpu_active(). | |
326 | */ | |
327 | ||
e0b582ec | 328 | err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu)); |
04321587 | 329 | if (err) { |
1da177e4 | 330 | /* CPU didn't die: tell everyone. Can't complain. */ |
f97f8f06 | 331 | smpboot_unpark_threads(cpu); |
e9fb7631 | 332 | cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu); |
6a1bdc1b | 333 | goto out_release; |
8fa1d7d3 | 334 | } |
04321587 | 335 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 336 | |
48c5ccae PZ |
337 | /* |
338 | * The migration_call() CPU_DYING callback will have removed all | |
339 | * runnable tasks from the cpu, there's only the idle task left now | |
340 | * that the migration thread is done doing the stop_machine thing. | |
51a96c77 PZ |
341 | * |
342 | * Wait for the stop thread to go away. | |
48c5ccae | 343 | */ |
51a96c77 PZ |
344 | while (!idle_cpu(cpu)) |
345 | cpu_relax(); | |
1da177e4 LT |
346 | |
347 | /* This actually kills the CPU. */ | |
348 | __cpu_die(cpu); | |
349 | ||
1da177e4 | 350 | /* CPU is completely dead: tell everyone. Too late to complain. */ |
e9fb7631 | 351 | cpu_notify_nofail(CPU_DEAD | mod, hcpu); |
1da177e4 LT |
352 | |
353 | check_for_tasks(cpu); | |
354 | ||
baaca49f | 355 | out_release: |
d221938c | 356 | cpu_hotplug_done(); |
e9fb7631 AM |
357 | if (!err) |
358 | cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu); | |
e3920fb4 RW |
359 | return err; |
360 | } | |
361 | ||
514a20a5 | 362 | int __ref cpu_down(unsigned int cpu) |
e3920fb4 | 363 | { |
9ea09af3 | 364 | int err; |
e3920fb4 | 365 | |
d221938c | 366 | cpu_maps_update_begin(); |
e761b772 MK |
367 | |
368 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 369 | err = -EBUSY; |
e761b772 MK |
370 | goto out; |
371 | } | |
372 | ||
e761b772 | 373 | err = _cpu_down(cpu, 0); |
e3920fb4 | 374 | |
e761b772 | 375 | out: |
d221938c | 376 | cpu_maps_update_done(); |
1da177e4 LT |
377 | return err; |
378 | } | |
b62b8ef9 | 379 | EXPORT_SYMBOL(cpu_down); |
1da177e4 LT |
380 | #endif /*CONFIG_HOTPLUG_CPU*/ |
381 | ||
e3920fb4 | 382 | /* Requires cpu_add_remove_lock to be held */ |
0db0628d | 383 | static int _cpu_up(unsigned int cpu, int tasks_frozen) |
1da177e4 | 384 | { |
baaca49f | 385 | int ret, nr_calls = 0; |
1da177e4 | 386 | void *hcpu = (void *)(long)cpu; |
8bb78442 | 387 | unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; |
3bb5d2ee | 388 | struct task_struct *idle; |
1da177e4 | 389 | |
d221938c | 390 | cpu_hotplug_begin(); |
38498a67 | 391 | |
5e5041f3 YI |
392 | if (cpu_online(cpu) || !cpu_present(cpu)) { |
393 | ret = -EINVAL; | |
394 | goto out; | |
395 | } | |
396 | ||
3bb5d2ee SS |
397 | idle = idle_thread_get(cpu); |
398 | if (IS_ERR(idle)) { | |
399 | ret = PTR_ERR(idle); | |
38498a67 | 400 | goto out; |
3bb5d2ee | 401 | } |
38498a67 | 402 | |
f97f8f06 TG |
403 | ret = smpboot_create_threads(cpu); |
404 | if (ret) | |
405 | goto out; | |
406 | ||
e9fb7631 | 407 | ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls); |
e6bde73b | 408 | if (ret) { |
a0d8cdb6 | 409 | nr_calls--; |
4d51985e | 410 | printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n", |
af1f16d0 | 411 | __func__, cpu); |
1da177e4 LT |
412 | goto out_notify; |
413 | } | |
414 | ||
415 | /* Arch-specific enabling code. */ | |
3bb5d2ee | 416 | ret = __cpu_up(cpu, idle); |
1da177e4 LT |
417 | if (ret != 0) |
418 | goto out_notify; | |
6978c705 | 419 | BUG_ON(!cpu_online(cpu)); |
1da177e4 | 420 | |
f97f8f06 TG |
421 | /* Wake the per cpu threads */ |
422 | smpboot_unpark_threads(cpu); | |
423 | ||
1da177e4 | 424 | /* Now call notifier in preparation. */ |
e9fb7631 | 425 | cpu_notify(CPU_ONLINE | mod, hcpu); |
1da177e4 LT |
426 | |
427 | out_notify: | |
428 | if (ret != 0) | |
e9fb7631 | 429 | __cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL); |
38498a67 | 430 | out: |
d221938c | 431 | cpu_hotplug_done(); |
e3920fb4 RW |
432 | |
433 | return ret; | |
434 | } | |
435 | ||
0db0628d | 436 | int cpu_up(unsigned int cpu) |
e3920fb4 RW |
437 | { |
438 | int err = 0; | |
cf23422b | 439 | |
e0b582ec | 440 | if (!cpu_possible(cpu)) { |
73e753a5 KH |
441 | printk(KERN_ERR "can't online cpu %d because it is not " |
442 | "configured as may-hotadd at boot time\n", cpu); | |
87d5e023 | 443 | #if defined(CONFIG_IA64) |
73e753a5 KH |
444 | printk(KERN_ERR "please check additional_cpus= boot " |
445 | "parameter\n"); | |
446 | #endif | |
447 | return -EINVAL; | |
448 | } | |
e3920fb4 | 449 | |
01b0f197 TK |
450 | err = try_online_node(cpu_to_node(cpu)); |
451 | if (err) | |
452 | return err; | |
cf23422b | 453 | |
d221938c | 454 | cpu_maps_update_begin(); |
e761b772 MK |
455 | |
456 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 457 | err = -EBUSY; |
e761b772 MK |
458 | goto out; |
459 | } | |
460 | ||
461 | err = _cpu_up(cpu, 0); | |
462 | ||
e761b772 | 463 | out: |
d221938c | 464 | cpu_maps_update_done(); |
e3920fb4 RW |
465 | return err; |
466 | } | |
a513f6ba | 467 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 468 | |
f3de4be9 | 469 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 470 | static cpumask_var_t frozen_cpus; |
e3920fb4 RW |
471 | |
472 | int disable_nonboot_cpus(void) | |
473 | { | |
e9a5f426 | 474 | int cpu, first_cpu, error = 0; |
e3920fb4 | 475 | |
d221938c | 476 | cpu_maps_update_begin(); |
e0b582ec | 477 | first_cpu = cpumask_first(cpu_online_mask); |
9ee349ad XF |
478 | /* |
479 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
480 | * with the userspace trying to use the CPU hotplug at the same time |
481 | */ | |
e0b582ec | 482 | cpumask_clear(frozen_cpus); |
6ad4c188 | 483 | |
e3920fb4 RW |
484 | printk("Disabling non-boot CPUs ...\n"); |
485 | for_each_online_cpu(cpu) { | |
486 | if (cpu == first_cpu) | |
487 | continue; | |
8bb78442 | 488 | error = _cpu_down(cpu, 1); |
feae3203 | 489 | if (!error) |
e0b582ec | 490 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 491 | else { |
e3920fb4 RW |
492 | printk(KERN_ERR "Error taking CPU%d down: %d\n", |
493 | cpu, error); | |
494 | break; | |
495 | } | |
496 | } | |
86886e55 | 497 | |
e3920fb4 RW |
498 | if (!error) { |
499 | BUG_ON(num_online_cpus() > 1); | |
500 | /* Make sure the CPUs won't be enabled by someone else */ | |
501 | cpu_hotplug_disabled = 1; | |
502 | } else { | |
e1d9fd2e | 503 | printk(KERN_ERR "Non-boot CPUs are not disabled\n"); |
e3920fb4 | 504 | } |
d221938c | 505 | cpu_maps_update_done(); |
e3920fb4 RW |
506 | return error; |
507 | } | |
508 | ||
d0af9eed SS |
509 | void __weak arch_enable_nonboot_cpus_begin(void) |
510 | { | |
511 | } | |
512 | ||
513 | void __weak arch_enable_nonboot_cpus_end(void) | |
514 | { | |
515 | } | |
516 | ||
fa7303e2 | 517 | void __ref enable_nonboot_cpus(void) |
e3920fb4 RW |
518 | { |
519 | int cpu, error; | |
520 | ||
521 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 522 | cpu_maps_update_begin(); |
e3920fb4 | 523 | cpu_hotplug_disabled = 0; |
e0b582ec | 524 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 525 | goto out; |
e3920fb4 | 526 | |
4d51985e | 527 | printk(KERN_INFO "Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
528 | |
529 | arch_enable_nonboot_cpus_begin(); | |
530 | ||
e0b582ec | 531 | for_each_cpu(cpu, frozen_cpus) { |
8bb78442 | 532 | error = _cpu_up(cpu, 1); |
e3920fb4 | 533 | if (!error) { |
4d51985e | 534 | printk(KERN_INFO "CPU%d is up\n", cpu); |
e3920fb4 RW |
535 | continue; |
536 | } | |
1d64b9cb | 537 | printk(KERN_WARNING "Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 538 | } |
d0af9eed SS |
539 | |
540 | arch_enable_nonboot_cpus_end(); | |
541 | ||
e0b582ec | 542 | cpumask_clear(frozen_cpus); |
1d64b9cb | 543 | out: |
d221938c | 544 | cpu_maps_update_done(); |
1da177e4 | 545 | } |
e0b582ec | 546 | |
d7268a31 | 547 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
548 | { |
549 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
550 | return -ENOMEM; | |
551 | return 0; | |
552 | } | |
553 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 554 | |
79cfbdfa SB |
555 | /* |
556 | * When callbacks for CPU hotplug notifications are being executed, we must | |
557 | * ensure that the state of the system with respect to the tasks being frozen | |
558 | * or not, as reported by the notification, remains unchanged *throughout the | |
559 | * duration* of the execution of the callbacks. | |
560 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
561 | * | |
562 | * This synchronization is implemented by mutually excluding regular CPU | |
563 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
564 | * Hibernate notifications. | |
565 | */ | |
566 | static int | |
567 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
568 | unsigned long action, void *ptr) | |
569 | { | |
570 | switch (action) { | |
571 | ||
572 | case PM_SUSPEND_PREPARE: | |
573 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 574 | cpu_hotplug_disable(); |
79cfbdfa SB |
575 | break; |
576 | ||
577 | case PM_POST_SUSPEND: | |
578 | case PM_POST_HIBERNATION: | |
16e53dbf | 579 | cpu_hotplug_enable(); |
79cfbdfa SB |
580 | break; |
581 | ||
582 | default: | |
583 | return NOTIFY_DONE; | |
584 | } | |
585 | ||
586 | return NOTIFY_OK; | |
587 | } | |
588 | ||
589 | ||
d7268a31 | 590 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 591 | { |
6e32d479 FY |
592 | /* |
593 | * cpu_hotplug_pm_callback has higher priority than x86 | |
594 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
595 | * to disable cpu hotplug to avoid cpu hotplug race. | |
596 | */ | |
79cfbdfa SB |
597 | pm_notifier(cpu_hotplug_pm_callback, 0); |
598 | return 0; | |
599 | } | |
600 | core_initcall(cpu_hotplug_pm_sync_init); | |
601 | ||
f3de4be9 | 602 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 603 | |
e545a614 MS |
604 | /** |
605 | * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers | |
606 | * @cpu: cpu that just started | |
607 | * | |
608 | * This function calls the cpu_chain notifiers with CPU_STARTING. | |
609 | * It must be called by the arch code on the new cpu, before the new cpu | |
610 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
611 | */ | |
0db0628d | 612 | void notify_cpu_starting(unsigned int cpu) |
e545a614 MS |
613 | { |
614 | unsigned long val = CPU_STARTING; | |
615 | ||
616 | #ifdef CONFIG_PM_SLEEP_SMP | |
e0b582ec | 617 | if (frozen_cpus != NULL && cpumask_test_cpu(cpu, frozen_cpus)) |
e545a614 MS |
618 | val = CPU_STARTING_FROZEN; |
619 | #endif /* CONFIG_PM_SLEEP_SMP */ | |
e9fb7631 | 620 | cpu_notify(val, (void *)(long)cpu); |
e545a614 MS |
621 | } |
622 | ||
68f4f1ec | 623 | #endif /* CONFIG_SMP */ |
b8d317d1 | 624 | |
e56b3bc7 LT |
625 | /* |
626 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
627 | * represents all NR_CPUS bits binary values of 1<<nr. | |
628 | * | |
e0b582ec | 629 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
630 | * mask value that has a single bit set only. |
631 | */ | |
b8d317d1 | 632 | |
e56b3bc7 | 633 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 634 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
635 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
636 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
637 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 638 | |
e56b3bc7 LT |
639 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
640 | ||
641 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
642 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
643 | #if BITS_PER_LONG > 32 | |
644 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
645 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
646 | #endif |
647 | }; | |
e56b3bc7 | 648 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
649 | |
650 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
651 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
652 | |
653 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
654 | static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly | |
655 | = CPU_BITS_ALL; | |
656 | #else | |
657 | static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly; | |
658 | #endif | |
659 | const struct cpumask *const cpu_possible_mask = to_cpumask(cpu_possible_bits); | |
660 | EXPORT_SYMBOL(cpu_possible_mask); | |
661 | ||
662 | static DECLARE_BITMAP(cpu_online_bits, CONFIG_NR_CPUS) __read_mostly; | |
663 | const struct cpumask *const cpu_online_mask = to_cpumask(cpu_online_bits); | |
664 | EXPORT_SYMBOL(cpu_online_mask); | |
665 | ||
666 | static DECLARE_BITMAP(cpu_present_bits, CONFIG_NR_CPUS) __read_mostly; | |
667 | const struct cpumask *const cpu_present_mask = to_cpumask(cpu_present_bits); | |
668 | EXPORT_SYMBOL(cpu_present_mask); | |
669 | ||
670 | static DECLARE_BITMAP(cpu_active_bits, CONFIG_NR_CPUS) __read_mostly; | |
671 | const struct cpumask *const cpu_active_mask = to_cpumask(cpu_active_bits); | |
672 | EXPORT_SYMBOL(cpu_active_mask); | |
3fa41520 RR |
673 | |
674 | void set_cpu_possible(unsigned int cpu, bool possible) | |
675 | { | |
676 | if (possible) | |
677 | cpumask_set_cpu(cpu, to_cpumask(cpu_possible_bits)); | |
678 | else | |
679 | cpumask_clear_cpu(cpu, to_cpumask(cpu_possible_bits)); | |
680 | } | |
681 | ||
682 | void set_cpu_present(unsigned int cpu, bool present) | |
683 | { | |
684 | if (present) | |
685 | cpumask_set_cpu(cpu, to_cpumask(cpu_present_bits)); | |
686 | else | |
687 | cpumask_clear_cpu(cpu, to_cpumask(cpu_present_bits)); | |
688 | } | |
689 | ||
690 | void set_cpu_online(unsigned int cpu, bool online) | |
691 | { | |
692 | if (online) | |
693 | cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits)); | |
694 | else | |
695 | cpumask_clear_cpu(cpu, to_cpumask(cpu_online_bits)); | |
696 | } | |
697 | ||
698 | void set_cpu_active(unsigned int cpu, bool active) | |
699 | { | |
700 | if (active) | |
701 | cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits)); | |
702 | else | |
703 | cpumask_clear_cpu(cpu, to_cpumask(cpu_active_bits)); | |
704 | } | |
705 | ||
706 | void init_cpu_present(const struct cpumask *src) | |
707 | { | |
708 | cpumask_copy(to_cpumask(cpu_present_bits), src); | |
709 | } | |
710 | ||
711 | void init_cpu_possible(const struct cpumask *src) | |
712 | { | |
713 | cpumask_copy(to_cpumask(cpu_possible_bits), src); | |
714 | } | |
715 | ||
716 | void init_cpu_online(const struct cpumask *src) | |
717 | { | |
718 | cpumask_copy(to_cpumask(cpu_online_bits), src); | |
719 | } |