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Commit | Line | Data |
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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 | */ | |
116 | static void cpu_hotplug_begin(void) | |
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 | ||
130 | static void cpu_hotplug_done(void) | |
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 | ||
79a6cdeb LJ |
157 | #else /* #if CONFIG_HOTPLUG_CPU */ |
158 | static void cpu_hotplug_begin(void) {} | |
159 | static void cpu_hotplug_done(void) {} | |
25985edc | 160 | #endif /* #else #if CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 161 | |
1da177e4 | 162 | /* Need to know about CPUs going up/down? */ |
f7b16c10 | 163 | int __ref register_cpu_notifier(struct notifier_block *nb) |
1da177e4 | 164 | { |
bd5349cf | 165 | int ret; |
d221938c | 166 | cpu_maps_update_begin(); |
bd5349cf | 167 | ret = raw_notifier_chain_register(&cpu_chain, nb); |
d221938c | 168 | cpu_maps_update_done(); |
bd5349cf | 169 | return ret; |
1da177e4 | 170 | } |
65edc68c | 171 | |
e9fb7631 AM |
172 | static int __cpu_notify(unsigned long val, void *v, int nr_to_call, |
173 | int *nr_calls) | |
174 | { | |
e6bde73b AM |
175 | int ret; |
176 | ||
177 | ret = __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call, | |
e9fb7631 | 178 | nr_calls); |
e6bde73b AM |
179 | |
180 | return notifier_to_errno(ret); | |
e9fb7631 AM |
181 | } |
182 | ||
183 | static int cpu_notify(unsigned long val, void *v) | |
184 | { | |
185 | return __cpu_notify(val, v, -1, NULL); | |
186 | } | |
187 | ||
00b9b0af LT |
188 | #ifdef CONFIG_HOTPLUG_CPU |
189 | ||
e9fb7631 AM |
190 | static void cpu_notify_nofail(unsigned long val, void *v) |
191 | { | |
00b9b0af | 192 | BUG_ON(cpu_notify(val, v)); |
e9fb7631 | 193 | } |
1da177e4 LT |
194 | EXPORT_SYMBOL(register_cpu_notifier); |
195 | ||
9647155f | 196 | void __ref unregister_cpu_notifier(struct notifier_block *nb) |
1da177e4 | 197 | { |
d221938c | 198 | cpu_maps_update_begin(); |
bd5349cf | 199 | raw_notifier_chain_unregister(&cpu_chain, nb); |
d221938c | 200 | cpu_maps_update_done(); |
1da177e4 LT |
201 | } |
202 | EXPORT_SYMBOL(unregister_cpu_notifier); | |
203 | ||
e4cc2f87 AV |
204 | /** |
205 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
206 | * @cpu: a CPU id | |
207 | * | |
208 | * This function walks all processes, finds a valid mm struct for each one and | |
209 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
210 | * trivial, there are various non-obvious corner cases, which this function | |
211 | * tries to solve in a safe manner. | |
212 | * | |
213 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
214 | * be called only for an already offlined CPU. | |
215 | */ | |
cb79295e AV |
216 | void clear_tasks_mm_cpumask(int cpu) |
217 | { | |
218 | struct task_struct *p; | |
219 | ||
220 | /* | |
221 | * This function is called after the cpu is taken down and marked | |
222 | * offline, so its not like new tasks will ever get this cpu set in | |
223 | * their mm mask. -- Peter Zijlstra | |
224 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
225 | * full-fledged tasklist_lock. | |
226 | */ | |
e4cc2f87 | 227 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
228 | rcu_read_lock(); |
229 | for_each_process(p) { | |
230 | struct task_struct *t; | |
231 | ||
e4cc2f87 AV |
232 | /* |
233 | * Main thread might exit, but other threads may still have | |
234 | * a valid mm. Find one. | |
235 | */ | |
cb79295e AV |
236 | t = find_lock_task_mm(p); |
237 | if (!t) | |
238 | continue; | |
239 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
240 | task_unlock(t); | |
241 | } | |
242 | rcu_read_unlock(); | |
243 | } | |
244 | ||
1da177e4 LT |
245 | static inline void check_for_tasks(int cpu) |
246 | { | |
247 | struct task_struct *p; | |
6fac4829 | 248 | cputime_t utime, stime; |
1da177e4 LT |
249 | |
250 | write_lock_irq(&tasklist_lock); | |
251 | for_each_process(p) { | |
6fac4829 | 252 | task_cputime(p, &utime, &stime); |
11854247 | 253 | if (task_cpu(p) == cpu && p->state == TASK_RUNNING && |
6fac4829 | 254 | (utime || stime)) |
9d3cfc4c FP |
255 | printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d " |
256 | "(state = %ld, flags = %x)\n", | |
257 | p->comm, task_pid_nr(p), cpu, | |
258 | p->state, p->flags); | |
1da177e4 LT |
259 | } |
260 | write_unlock_irq(&tasklist_lock); | |
261 | } | |
262 | ||
db912f96 AK |
263 | struct take_cpu_down_param { |
264 | unsigned long mod; | |
265 | void *hcpu; | |
266 | }; | |
267 | ||
1da177e4 | 268 | /* Take this CPU down. */ |
514a20a5 | 269 | static int __ref take_cpu_down(void *_param) |
1da177e4 | 270 | { |
db912f96 | 271 | struct take_cpu_down_param *param = _param; |
1da177e4 LT |
272 | int err; |
273 | ||
1da177e4 LT |
274 | /* Ensure this CPU doesn't handle any more interrupts. */ |
275 | err = __cpu_disable(); | |
276 | if (err < 0) | |
f3705136 | 277 | return err; |
1da177e4 | 278 | |
e9fb7631 | 279 | cpu_notify(CPU_DYING | param->mod, param->hcpu); |
14e568e7 TG |
280 | /* Park the stopper thread */ |
281 | kthread_park(current); | |
f3705136 | 282 | return 0; |
1da177e4 LT |
283 | } |
284 | ||
e3920fb4 | 285 | /* Requires cpu_add_remove_lock to be held */ |
514a20a5 | 286 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) |
1da177e4 | 287 | { |
e7407dcc | 288 | int err, nr_calls = 0; |
e7407dcc | 289 | void *hcpu = (void *)(long)cpu; |
8bb78442 | 290 | unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; |
db912f96 AK |
291 | struct take_cpu_down_param tcd_param = { |
292 | .mod = mod, | |
293 | .hcpu = hcpu, | |
294 | }; | |
1da177e4 | 295 | |
e3920fb4 RW |
296 | if (num_online_cpus() == 1) |
297 | return -EBUSY; | |
1da177e4 | 298 | |
e3920fb4 RW |
299 | if (!cpu_online(cpu)) |
300 | return -EINVAL; | |
1da177e4 | 301 | |
d221938c | 302 | cpu_hotplug_begin(); |
4d51985e | 303 | |
e9fb7631 | 304 | err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls); |
e6bde73b | 305 | if (err) { |
a0d8cdb6 | 306 | nr_calls--; |
e9fb7631 | 307 | __cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL); |
1da177e4 | 308 | printk("%s: attempt to take down CPU %u failed\n", |
af1f16d0 | 309 | __func__, cpu); |
baaca49f | 310 | goto out_release; |
1da177e4 | 311 | } |
f97f8f06 | 312 | smpboot_park_threads(cpu); |
1da177e4 | 313 | |
e0b582ec | 314 | err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu)); |
04321587 | 315 | if (err) { |
1da177e4 | 316 | /* CPU didn't die: tell everyone. Can't complain. */ |
f97f8f06 | 317 | smpboot_unpark_threads(cpu); |
e9fb7631 | 318 | cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu); |
6a1bdc1b | 319 | goto out_release; |
8fa1d7d3 | 320 | } |
04321587 | 321 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 322 | |
48c5ccae PZ |
323 | /* |
324 | * The migration_call() CPU_DYING callback will have removed all | |
325 | * runnable tasks from the cpu, there's only the idle task left now | |
326 | * that the migration thread is done doing the stop_machine thing. | |
51a96c77 PZ |
327 | * |
328 | * Wait for the stop thread to go away. | |
48c5ccae | 329 | */ |
51a96c77 PZ |
330 | while (!idle_cpu(cpu)) |
331 | cpu_relax(); | |
1da177e4 LT |
332 | |
333 | /* This actually kills the CPU. */ | |
334 | __cpu_die(cpu); | |
335 | ||
1da177e4 | 336 | /* CPU is completely dead: tell everyone. Too late to complain. */ |
e9fb7631 | 337 | cpu_notify_nofail(CPU_DEAD | mod, hcpu); |
1da177e4 LT |
338 | |
339 | check_for_tasks(cpu); | |
340 | ||
baaca49f | 341 | out_release: |
d221938c | 342 | cpu_hotplug_done(); |
e9fb7631 AM |
343 | if (!err) |
344 | cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu); | |
e3920fb4 RW |
345 | return err; |
346 | } | |
347 | ||
514a20a5 | 348 | int __ref cpu_down(unsigned int cpu) |
e3920fb4 | 349 | { |
9ea09af3 | 350 | int err; |
e3920fb4 | 351 | |
d221938c | 352 | cpu_maps_update_begin(); |
e761b772 MK |
353 | |
354 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 355 | err = -EBUSY; |
e761b772 MK |
356 | goto out; |
357 | } | |
358 | ||
e761b772 | 359 | err = _cpu_down(cpu, 0); |
e3920fb4 | 360 | |
e761b772 | 361 | out: |
d221938c | 362 | cpu_maps_update_done(); |
1da177e4 LT |
363 | return err; |
364 | } | |
b62b8ef9 | 365 | EXPORT_SYMBOL(cpu_down); |
1da177e4 LT |
366 | #endif /*CONFIG_HOTPLUG_CPU*/ |
367 | ||
e3920fb4 | 368 | /* Requires cpu_add_remove_lock to be held */ |
0db0628d | 369 | static int _cpu_up(unsigned int cpu, int tasks_frozen) |
1da177e4 | 370 | { |
baaca49f | 371 | int ret, nr_calls = 0; |
1da177e4 | 372 | void *hcpu = (void *)(long)cpu; |
8bb78442 | 373 | unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; |
3bb5d2ee | 374 | struct task_struct *idle; |
1da177e4 | 375 | |
d221938c | 376 | cpu_hotplug_begin(); |
38498a67 | 377 | |
5e5041f3 YI |
378 | if (cpu_online(cpu) || !cpu_present(cpu)) { |
379 | ret = -EINVAL; | |
380 | goto out; | |
381 | } | |
382 | ||
3bb5d2ee SS |
383 | idle = idle_thread_get(cpu); |
384 | if (IS_ERR(idle)) { | |
385 | ret = PTR_ERR(idle); | |
38498a67 | 386 | goto out; |
3bb5d2ee | 387 | } |
38498a67 | 388 | |
f97f8f06 TG |
389 | ret = smpboot_create_threads(cpu); |
390 | if (ret) | |
391 | goto out; | |
392 | ||
e9fb7631 | 393 | ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls); |
e6bde73b | 394 | if (ret) { |
a0d8cdb6 | 395 | nr_calls--; |
4d51985e | 396 | printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n", |
af1f16d0 | 397 | __func__, cpu); |
1da177e4 LT |
398 | goto out_notify; |
399 | } | |
400 | ||
401 | /* Arch-specific enabling code. */ | |
3bb5d2ee | 402 | ret = __cpu_up(cpu, idle); |
1da177e4 LT |
403 | if (ret != 0) |
404 | goto out_notify; | |
6978c705 | 405 | BUG_ON(!cpu_online(cpu)); |
1da177e4 | 406 | |
f97f8f06 TG |
407 | /* Wake the per cpu threads */ |
408 | smpboot_unpark_threads(cpu); | |
409 | ||
1da177e4 | 410 | /* Now call notifier in preparation. */ |
e9fb7631 | 411 | cpu_notify(CPU_ONLINE | mod, hcpu); |
1da177e4 LT |
412 | |
413 | out_notify: | |
414 | if (ret != 0) | |
e9fb7631 | 415 | __cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL); |
38498a67 | 416 | out: |
d221938c | 417 | cpu_hotplug_done(); |
e3920fb4 RW |
418 | |
419 | return ret; | |
420 | } | |
421 | ||
0db0628d | 422 | int cpu_up(unsigned int cpu) |
e3920fb4 RW |
423 | { |
424 | int err = 0; | |
cf23422b | 425 | |
426 | #ifdef CONFIG_MEMORY_HOTPLUG | |
427 | int nid; | |
428 | pg_data_t *pgdat; | |
429 | #endif | |
430 | ||
e0b582ec | 431 | if (!cpu_possible(cpu)) { |
73e753a5 KH |
432 | printk(KERN_ERR "can't online cpu %d because it is not " |
433 | "configured as may-hotadd at boot time\n", cpu); | |
87d5e023 | 434 | #if defined(CONFIG_IA64) |
73e753a5 KH |
435 | printk(KERN_ERR "please check additional_cpus= boot " |
436 | "parameter\n"); | |
437 | #endif | |
438 | return -EINVAL; | |
439 | } | |
e3920fb4 | 440 | |
cf23422b | 441 | #ifdef CONFIG_MEMORY_HOTPLUG |
442 | nid = cpu_to_node(cpu); | |
443 | if (!node_online(nid)) { | |
444 | err = mem_online_node(nid); | |
445 | if (err) | |
446 | return err; | |
447 | } | |
448 | ||
449 | pgdat = NODE_DATA(nid); | |
450 | if (!pgdat) { | |
451 | printk(KERN_ERR | |
452 | "Can't online cpu %d due to NULL pgdat\n", cpu); | |
453 | return -ENOMEM; | |
454 | } | |
455 | ||
4eaf3f64 HL |
456 | if (pgdat->node_zonelists->_zonerefs->zone == NULL) { |
457 | mutex_lock(&zonelists_mutex); | |
9adb62a5 | 458 | build_all_zonelists(NULL, NULL); |
4eaf3f64 HL |
459 | mutex_unlock(&zonelists_mutex); |
460 | } | |
cf23422b | 461 | #endif |
462 | ||
d221938c | 463 | cpu_maps_update_begin(); |
e761b772 MK |
464 | |
465 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 466 | err = -EBUSY; |
e761b772 MK |
467 | goto out; |
468 | } | |
469 | ||
470 | err = _cpu_up(cpu, 0); | |
471 | ||
e761b772 | 472 | out: |
d221938c | 473 | cpu_maps_update_done(); |
e3920fb4 RW |
474 | return err; |
475 | } | |
a513f6ba | 476 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 477 | |
f3de4be9 | 478 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 479 | static cpumask_var_t frozen_cpus; |
e3920fb4 RW |
480 | |
481 | int disable_nonboot_cpus(void) | |
482 | { | |
e9a5f426 | 483 | int cpu, first_cpu, error = 0; |
e3920fb4 | 484 | |
d221938c | 485 | cpu_maps_update_begin(); |
e0b582ec | 486 | first_cpu = cpumask_first(cpu_online_mask); |
9ee349ad XF |
487 | /* |
488 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
489 | * with the userspace trying to use the CPU hotplug at the same time |
490 | */ | |
e0b582ec | 491 | cpumask_clear(frozen_cpus); |
6ad4c188 | 492 | |
e3920fb4 RW |
493 | printk("Disabling non-boot CPUs ...\n"); |
494 | for_each_online_cpu(cpu) { | |
495 | if (cpu == first_cpu) | |
496 | continue; | |
8bb78442 | 497 | error = _cpu_down(cpu, 1); |
feae3203 | 498 | if (!error) |
e0b582ec | 499 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 500 | else { |
e3920fb4 RW |
501 | printk(KERN_ERR "Error taking CPU%d down: %d\n", |
502 | cpu, error); | |
503 | break; | |
504 | } | |
505 | } | |
86886e55 | 506 | |
e3920fb4 RW |
507 | if (!error) { |
508 | BUG_ON(num_online_cpus() > 1); | |
509 | /* Make sure the CPUs won't be enabled by someone else */ | |
510 | cpu_hotplug_disabled = 1; | |
511 | } else { | |
e1d9fd2e | 512 | printk(KERN_ERR "Non-boot CPUs are not disabled\n"); |
e3920fb4 | 513 | } |
d221938c | 514 | cpu_maps_update_done(); |
e3920fb4 RW |
515 | return error; |
516 | } | |
517 | ||
d0af9eed SS |
518 | void __weak arch_enable_nonboot_cpus_begin(void) |
519 | { | |
520 | } | |
521 | ||
522 | void __weak arch_enable_nonboot_cpus_end(void) | |
523 | { | |
524 | } | |
525 | ||
fa7303e2 | 526 | void __ref enable_nonboot_cpus(void) |
e3920fb4 RW |
527 | { |
528 | int cpu, error; | |
529 | ||
530 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 531 | cpu_maps_update_begin(); |
e3920fb4 | 532 | cpu_hotplug_disabled = 0; |
e0b582ec | 533 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 534 | goto out; |
e3920fb4 | 535 | |
4d51985e | 536 | printk(KERN_INFO "Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
537 | |
538 | arch_enable_nonboot_cpus_begin(); | |
539 | ||
e0b582ec | 540 | for_each_cpu(cpu, frozen_cpus) { |
8bb78442 | 541 | error = _cpu_up(cpu, 1); |
e3920fb4 | 542 | if (!error) { |
4d51985e | 543 | printk(KERN_INFO "CPU%d is up\n", cpu); |
e3920fb4 RW |
544 | continue; |
545 | } | |
1d64b9cb | 546 | printk(KERN_WARNING "Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 547 | } |
d0af9eed SS |
548 | |
549 | arch_enable_nonboot_cpus_end(); | |
550 | ||
e0b582ec | 551 | cpumask_clear(frozen_cpus); |
1d64b9cb | 552 | out: |
d221938c | 553 | cpu_maps_update_done(); |
1da177e4 | 554 | } |
e0b582ec | 555 | |
d7268a31 | 556 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
557 | { |
558 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
559 | return -ENOMEM; | |
560 | return 0; | |
561 | } | |
562 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 563 | |
79cfbdfa SB |
564 | /* |
565 | * When callbacks for CPU hotplug notifications are being executed, we must | |
566 | * ensure that the state of the system with respect to the tasks being frozen | |
567 | * or not, as reported by the notification, remains unchanged *throughout the | |
568 | * duration* of the execution of the callbacks. | |
569 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
570 | * | |
571 | * This synchronization is implemented by mutually excluding regular CPU | |
572 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
573 | * Hibernate notifications. | |
574 | */ | |
575 | static int | |
576 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
577 | unsigned long action, void *ptr) | |
578 | { | |
579 | switch (action) { | |
580 | ||
581 | case PM_SUSPEND_PREPARE: | |
582 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 583 | cpu_hotplug_disable(); |
79cfbdfa SB |
584 | break; |
585 | ||
586 | case PM_POST_SUSPEND: | |
587 | case PM_POST_HIBERNATION: | |
16e53dbf | 588 | cpu_hotplug_enable(); |
79cfbdfa SB |
589 | break; |
590 | ||
591 | default: | |
592 | return NOTIFY_DONE; | |
593 | } | |
594 | ||
595 | return NOTIFY_OK; | |
596 | } | |
597 | ||
598 | ||
d7268a31 | 599 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 600 | { |
6e32d479 FY |
601 | /* |
602 | * cpu_hotplug_pm_callback has higher priority than x86 | |
603 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
604 | * to disable cpu hotplug to avoid cpu hotplug race. | |
605 | */ | |
79cfbdfa SB |
606 | pm_notifier(cpu_hotplug_pm_callback, 0); |
607 | return 0; | |
608 | } | |
609 | core_initcall(cpu_hotplug_pm_sync_init); | |
610 | ||
f3de4be9 | 611 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 612 | |
e545a614 MS |
613 | /** |
614 | * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers | |
615 | * @cpu: cpu that just started | |
616 | * | |
617 | * This function calls the cpu_chain notifiers with CPU_STARTING. | |
618 | * It must be called by the arch code on the new cpu, before the new cpu | |
619 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
620 | */ | |
0db0628d | 621 | void notify_cpu_starting(unsigned int cpu) |
e545a614 MS |
622 | { |
623 | unsigned long val = CPU_STARTING; | |
624 | ||
625 | #ifdef CONFIG_PM_SLEEP_SMP | |
e0b582ec | 626 | if (frozen_cpus != NULL && cpumask_test_cpu(cpu, frozen_cpus)) |
e545a614 MS |
627 | val = CPU_STARTING_FROZEN; |
628 | #endif /* CONFIG_PM_SLEEP_SMP */ | |
e9fb7631 | 629 | cpu_notify(val, (void *)(long)cpu); |
e545a614 MS |
630 | } |
631 | ||
68f4f1ec | 632 | #endif /* CONFIG_SMP */ |
b8d317d1 | 633 | |
e56b3bc7 LT |
634 | /* |
635 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
636 | * represents all NR_CPUS bits binary values of 1<<nr. | |
637 | * | |
e0b582ec | 638 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
639 | * mask value that has a single bit set only. |
640 | */ | |
b8d317d1 | 641 | |
e56b3bc7 | 642 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 643 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
644 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
645 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
646 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 647 | |
e56b3bc7 LT |
648 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
649 | ||
650 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
651 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
652 | #if BITS_PER_LONG > 32 | |
653 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
654 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
655 | #endif |
656 | }; | |
e56b3bc7 | 657 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
658 | |
659 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
660 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
661 | |
662 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
663 | static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly | |
664 | = CPU_BITS_ALL; | |
665 | #else | |
666 | static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly; | |
667 | #endif | |
668 | const struct cpumask *const cpu_possible_mask = to_cpumask(cpu_possible_bits); | |
669 | EXPORT_SYMBOL(cpu_possible_mask); | |
670 | ||
671 | static DECLARE_BITMAP(cpu_online_bits, CONFIG_NR_CPUS) __read_mostly; | |
672 | const struct cpumask *const cpu_online_mask = to_cpumask(cpu_online_bits); | |
673 | EXPORT_SYMBOL(cpu_online_mask); | |
674 | ||
675 | static DECLARE_BITMAP(cpu_present_bits, CONFIG_NR_CPUS) __read_mostly; | |
676 | const struct cpumask *const cpu_present_mask = to_cpumask(cpu_present_bits); | |
677 | EXPORT_SYMBOL(cpu_present_mask); | |
678 | ||
679 | static DECLARE_BITMAP(cpu_active_bits, CONFIG_NR_CPUS) __read_mostly; | |
680 | const struct cpumask *const cpu_active_mask = to_cpumask(cpu_active_bits); | |
681 | EXPORT_SYMBOL(cpu_active_mask); | |
3fa41520 RR |
682 | |
683 | void set_cpu_possible(unsigned int cpu, bool possible) | |
684 | { | |
685 | if (possible) | |
686 | cpumask_set_cpu(cpu, to_cpumask(cpu_possible_bits)); | |
687 | else | |
688 | cpumask_clear_cpu(cpu, to_cpumask(cpu_possible_bits)); | |
689 | } | |
690 | ||
691 | void set_cpu_present(unsigned int cpu, bool present) | |
692 | { | |
693 | if (present) | |
694 | cpumask_set_cpu(cpu, to_cpumask(cpu_present_bits)); | |
695 | else | |
696 | cpumask_clear_cpu(cpu, to_cpumask(cpu_present_bits)); | |
697 | } | |
698 | ||
699 | void set_cpu_online(unsigned int cpu, bool online) | |
700 | { | |
701 | if (online) | |
702 | cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits)); | |
703 | else | |
704 | cpumask_clear_cpu(cpu, to_cpumask(cpu_online_bits)); | |
705 | } | |
706 | ||
707 | void set_cpu_active(unsigned int cpu, bool active) | |
708 | { | |
709 | if (active) | |
710 | cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits)); | |
711 | else | |
712 | cpumask_clear_cpu(cpu, to_cpumask(cpu_active_bits)); | |
713 | } | |
714 | ||
715 | void init_cpu_present(const struct cpumask *src) | |
716 | { | |
717 | cpumask_copy(to_cpumask(cpu_present_bits), src); | |
718 | } | |
719 | ||
720 | void init_cpu_possible(const struct cpumask *src) | |
721 | { | |
722 | cpumask_copy(to_cpumask(cpu_possible_bits), src); | |
723 | } | |
724 | ||
725 | void init_cpu_online(const struct cpumask *src) | |
726 | { | |
727 | cpumask_copy(to_cpumask(cpu_online_bits), src); | |
728 | } |