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); |
d2ba7e2a ON |
83 | if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer)) |
84 | wake_up_process(cpu_hotplug.active_writer); | |
d221938c GS |
85 | mutex_unlock(&cpu_hotplug.lock); |
86 | ||
a9d9baa1 | 87 | } |
86ef5c9a | 88 | EXPORT_SYMBOL_GPL(put_online_cpus); |
a9d9baa1 | 89 | |
d221938c GS |
90 | /* |
91 | * This ensures that the hotplug operation can begin only when the | |
92 | * refcount goes to zero. | |
93 | * | |
94 | * Note that during a cpu-hotplug operation, the new readers, if any, | |
95 | * will be blocked by the cpu_hotplug.lock | |
96 | * | |
d2ba7e2a ON |
97 | * Since cpu_hotplug_begin() is always called after invoking |
98 | * cpu_maps_update_begin(), we can be sure that only one writer is active. | |
d221938c GS |
99 | * |
100 | * Note that theoretically, there is a possibility of a livelock: | |
101 | * - Refcount goes to zero, last reader wakes up the sleeping | |
102 | * writer. | |
103 | * - Last reader unlocks the cpu_hotplug.lock. | |
104 | * - A new reader arrives at this moment, bumps up the refcount. | |
105 | * - The writer acquires the cpu_hotplug.lock finds the refcount | |
106 | * non zero and goes to sleep again. | |
107 | * | |
108 | * However, this is very difficult to achieve in practice since | |
86ef5c9a | 109 | * get_online_cpus() not an api which is called all that often. |
d221938c GS |
110 | * |
111 | */ | |
112 | static void cpu_hotplug_begin(void) | |
113 | { | |
d221938c | 114 | cpu_hotplug.active_writer = current; |
d2ba7e2a ON |
115 | |
116 | for (;;) { | |
117 | mutex_lock(&cpu_hotplug.lock); | |
118 | if (likely(!cpu_hotplug.refcount)) | |
119 | break; | |
120 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
d221938c GS |
121 | mutex_unlock(&cpu_hotplug.lock); |
122 | schedule(); | |
d221938c | 123 | } |
d221938c GS |
124 | } |
125 | ||
126 | static void cpu_hotplug_done(void) | |
127 | { | |
128 | cpu_hotplug.active_writer = NULL; | |
129 | mutex_unlock(&cpu_hotplug.lock); | |
130 | } | |
79a6cdeb LJ |
131 | |
132 | #else /* #if CONFIG_HOTPLUG_CPU */ | |
133 | static void cpu_hotplug_begin(void) {} | |
134 | static void cpu_hotplug_done(void) {} | |
25985edc | 135 | #endif /* #else #if CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 136 | |
1da177e4 | 137 | /* Need to know about CPUs going up/down? */ |
f7b16c10 | 138 | int __ref register_cpu_notifier(struct notifier_block *nb) |
1da177e4 | 139 | { |
bd5349cf | 140 | int ret; |
d221938c | 141 | cpu_maps_update_begin(); |
bd5349cf | 142 | ret = raw_notifier_chain_register(&cpu_chain, nb); |
d221938c | 143 | cpu_maps_update_done(); |
bd5349cf | 144 | return ret; |
1da177e4 | 145 | } |
65edc68c | 146 | |
e9fb7631 AM |
147 | static int __cpu_notify(unsigned long val, void *v, int nr_to_call, |
148 | int *nr_calls) | |
149 | { | |
e6bde73b AM |
150 | int ret; |
151 | ||
152 | ret = __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call, | |
e9fb7631 | 153 | nr_calls); |
e6bde73b AM |
154 | |
155 | return notifier_to_errno(ret); | |
e9fb7631 AM |
156 | } |
157 | ||
158 | static int cpu_notify(unsigned long val, void *v) | |
159 | { | |
160 | return __cpu_notify(val, v, -1, NULL); | |
161 | } | |
162 | ||
00b9b0af LT |
163 | #ifdef CONFIG_HOTPLUG_CPU |
164 | ||
e9fb7631 AM |
165 | static void cpu_notify_nofail(unsigned long val, void *v) |
166 | { | |
00b9b0af | 167 | BUG_ON(cpu_notify(val, v)); |
e9fb7631 | 168 | } |
1da177e4 LT |
169 | EXPORT_SYMBOL(register_cpu_notifier); |
170 | ||
9647155f | 171 | void __ref unregister_cpu_notifier(struct notifier_block *nb) |
1da177e4 | 172 | { |
d221938c | 173 | cpu_maps_update_begin(); |
bd5349cf | 174 | raw_notifier_chain_unregister(&cpu_chain, nb); |
d221938c | 175 | cpu_maps_update_done(); |
1da177e4 LT |
176 | } |
177 | EXPORT_SYMBOL(unregister_cpu_notifier); | |
178 | ||
e4cc2f87 AV |
179 | /** |
180 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
181 | * @cpu: a CPU id | |
182 | * | |
183 | * This function walks all processes, finds a valid mm struct for each one and | |
184 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
185 | * trivial, there are various non-obvious corner cases, which this function | |
186 | * tries to solve in a safe manner. | |
187 | * | |
188 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
189 | * be called only for an already offlined CPU. | |
190 | */ | |
cb79295e AV |
191 | void clear_tasks_mm_cpumask(int cpu) |
192 | { | |
193 | struct task_struct *p; | |
194 | ||
195 | /* | |
196 | * This function is called after the cpu is taken down and marked | |
197 | * offline, so its not like new tasks will ever get this cpu set in | |
198 | * their mm mask. -- Peter Zijlstra | |
199 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
200 | * full-fledged tasklist_lock. | |
201 | */ | |
e4cc2f87 | 202 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
203 | rcu_read_lock(); |
204 | for_each_process(p) { | |
205 | struct task_struct *t; | |
206 | ||
e4cc2f87 AV |
207 | /* |
208 | * Main thread might exit, but other threads may still have | |
209 | * a valid mm. Find one. | |
210 | */ | |
cb79295e AV |
211 | t = find_lock_task_mm(p); |
212 | if (!t) | |
213 | continue; | |
214 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
215 | task_unlock(t); | |
216 | } | |
217 | rcu_read_unlock(); | |
218 | } | |
219 | ||
1da177e4 LT |
220 | static inline void check_for_tasks(int cpu) |
221 | { | |
222 | struct task_struct *p; | |
223 | ||
224 | write_lock_irq(&tasklist_lock); | |
225 | for_each_process(p) { | |
11854247 | 226 | if (task_cpu(p) == cpu && p->state == TASK_RUNNING && |
64861634 | 227 | (p->utime || p->stime)) |
9d3cfc4c FP |
228 | printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d " |
229 | "(state = %ld, flags = %x)\n", | |
230 | p->comm, task_pid_nr(p), cpu, | |
231 | p->state, p->flags); | |
1da177e4 LT |
232 | } |
233 | write_unlock_irq(&tasklist_lock); | |
234 | } | |
235 | ||
db912f96 AK |
236 | struct take_cpu_down_param { |
237 | unsigned long mod; | |
238 | void *hcpu; | |
239 | }; | |
240 | ||
1da177e4 | 241 | /* Take this CPU down. */ |
514a20a5 | 242 | static int __ref take_cpu_down(void *_param) |
1da177e4 | 243 | { |
db912f96 | 244 | struct take_cpu_down_param *param = _param; |
1da177e4 LT |
245 | int err; |
246 | ||
1da177e4 LT |
247 | /* Ensure this CPU doesn't handle any more interrupts. */ |
248 | err = __cpu_disable(); | |
249 | if (err < 0) | |
f3705136 | 250 | return err; |
1da177e4 | 251 | |
e9fb7631 | 252 | cpu_notify(CPU_DYING | param->mod, param->hcpu); |
f3705136 | 253 | return 0; |
1da177e4 LT |
254 | } |
255 | ||
e3920fb4 | 256 | /* Requires cpu_add_remove_lock to be held */ |
514a20a5 | 257 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) |
1da177e4 | 258 | { |
e7407dcc | 259 | int err, nr_calls = 0; |
e7407dcc | 260 | void *hcpu = (void *)(long)cpu; |
8bb78442 | 261 | unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; |
db912f96 AK |
262 | struct take_cpu_down_param tcd_param = { |
263 | .mod = mod, | |
264 | .hcpu = hcpu, | |
265 | }; | |
1da177e4 | 266 | |
e3920fb4 RW |
267 | if (num_online_cpus() == 1) |
268 | return -EBUSY; | |
1da177e4 | 269 | |
e3920fb4 RW |
270 | if (!cpu_online(cpu)) |
271 | return -EINVAL; | |
1da177e4 | 272 | |
d221938c | 273 | cpu_hotplug_begin(); |
4d51985e | 274 | |
e9fb7631 | 275 | err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls); |
e6bde73b | 276 | if (err) { |
a0d8cdb6 | 277 | nr_calls--; |
e9fb7631 | 278 | __cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL); |
1da177e4 | 279 | printk("%s: attempt to take down CPU %u failed\n", |
af1f16d0 | 280 | __func__, cpu); |
baaca49f | 281 | goto out_release; |
1da177e4 | 282 | } |
f97f8f06 | 283 | smpboot_park_threads(cpu); |
1da177e4 | 284 | |
e0b582ec | 285 | err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu)); |
04321587 | 286 | if (err) { |
1da177e4 | 287 | /* CPU didn't die: tell everyone. Can't complain. */ |
f97f8f06 | 288 | smpboot_unpark_threads(cpu); |
e9fb7631 | 289 | cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu); |
6a1bdc1b | 290 | goto out_release; |
8fa1d7d3 | 291 | } |
04321587 | 292 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 293 | |
48c5ccae PZ |
294 | /* |
295 | * The migration_call() CPU_DYING callback will have removed all | |
296 | * runnable tasks from the cpu, there's only the idle task left now | |
297 | * that the migration thread is done doing the stop_machine thing. | |
51a96c77 PZ |
298 | * |
299 | * Wait for the stop thread to go away. | |
48c5ccae | 300 | */ |
51a96c77 PZ |
301 | while (!idle_cpu(cpu)) |
302 | cpu_relax(); | |
1da177e4 LT |
303 | |
304 | /* This actually kills the CPU. */ | |
305 | __cpu_die(cpu); | |
306 | ||
1da177e4 | 307 | /* CPU is completely dead: tell everyone. Too late to complain. */ |
e9fb7631 | 308 | cpu_notify_nofail(CPU_DEAD | mod, hcpu); |
1da177e4 LT |
309 | |
310 | check_for_tasks(cpu); | |
311 | ||
baaca49f | 312 | out_release: |
d221938c | 313 | cpu_hotplug_done(); |
e9fb7631 AM |
314 | if (!err) |
315 | cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu); | |
e3920fb4 RW |
316 | return err; |
317 | } | |
318 | ||
514a20a5 | 319 | int __ref cpu_down(unsigned int cpu) |
e3920fb4 | 320 | { |
9ea09af3 | 321 | int err; |
e3920fb4 | 322 | |
d221938c | 323 | cpu_maps_update_begin(); |
e761b772 MK |
324 | |
325 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 326 | err = -EBUSY; |
e761b772 MK |
327 | goto out; |
328 | } | |
329 | ||
e761b772 | 330 | err = _cpu_down(cpu, 0); |
e3920fb4 | 331 | |
e761b772 | 332 | out: |
d221938c | 333 | cpu_maps_update_done(); |
1da177e4 LT |
334 | return err; |
335 | } | |
b62b8ef9 | 336 | EXPORT_SYMBOL(cpu_down); |
1da177e4 LT |
337 | #endif /*CONFIG_HOTPLUG_CPU*/ |
338 | ||
e3920fb4 | 339 | /* Requires cpu_add_remove_lock to be held */ |
8bb78442 | 340 | static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen) |
1da177e4 | 341 | { |
baaca49f | 342 | int ret, nr_calls = 0; |
1da177e4 | 343 | void *hcpu = (void *)(long)cpu; |
8bb78442 | 344 | unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; |
3bb5d2ee | 345 | struct task_struct *idle; |
1da177e4 | 346 | |
e3920fb4 RW |
347 | if (cpu_online(cpu) || !cpu_present(cpu)) |
348 | return -EINVAL; | |
90d45d17 | 349 | |
d221938c | 350 | cpu_hotplug_begin(); |
38498a67 | 351 | |
3bb5d2ee SS |
352 | idle = idle_thread_get(cpu); |
353 | if (IS_ERR(idle)) { | |
354 | ret = PTR_ERR(idle); | |
38498a67 | 355 | goto out; |
3bb5d2ee | 356 | } |
38498a67 | 357 | |
f97f8f06 TG |
358 | ret = smpboot_create_threads(cpu); |
359 | if (ret) | |
360 | goto out; | |
361 | ||
e9fb7631 | 362 | ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls); |
e6bde73b | 363 | if (ret) { |
a0d8cdb6 | 364 | nr_calls--; |
4d51985e | 365 | printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n", |
af1f16d0 | 366 | __func__, cpu); |
1da177e4 LT |
367 | goto out_notify; |
368 | } | |
369 | ||
370 | /* Arch-specific enabling code. */ | |
3bb5d2ee | 371 | ret = __cpu_up(cpu, idle); |
1da177e4 LT |
372 | if (ret != 0) |
373 | goto out_notify; | |
6978c705 | 374 | BUG_ON(!cpu_online(cpu)); |
1da177e4 | 375 | |
f97f8f06 TG |
376 | /* Wake the per cpu threads */ |
377 | smpboot_unpark_threads(cpu); | |
378 | ||
1da177e4 | 379 | /* Now call notifier in preparation. */ |
e9fb7631 | 380 | cpu_notify(CPU_ONLINE | mod, hcpu); |
1da177e4 LT |
381 | |
382 | out_notify: | |
383 | if (ret != 0) | |
e9fb7631 | 384 | __cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL); |
38498a67 | 385 | out: |
d221938c | 386 | cpu_hotplug_done(); |
e3920fb4 RW |
387 | |
388 | return ret; | |
389 | } | |
390 | ||
b282b6f8 | 391 | int __cpuinit cpu_up(unsigned int cpu) |
e3920fb4 RW |
392 | { |
393 | int err = 0; | |
cf23422b | 394 | |
395 | #ifdef CONFIG_MEMORY_HOTPLUG | |
396 | int nid; | |
397 | pg_data_t *pgdat; | |
398 | #endif | |
399 | ||
e0b582ec | 400 | if (!cpu_possible(cpu)) { |
73e753a5 KH |
401 | printk(KERN_ERR "can't online cpu %d because it is not " |
402 | "configured as may-hotadd at boot time\n", cpu); | |
87d5e023 | 403 | #if defined(CONFIG_IA64) |
73e753a5 KH |
404 | printk(KERN_ERR "please check additional_cpus= boot " |
405 | "parameter\n"); | |
406 | #endif | |
407 | return -EINVAL; | |
408 | } | |
e3920fb4 | 409 | |
cf23422b | 410 | #ifdef CONFIG_MEMORY_HOTPLUG |
411 | nid = cpu_to_node(cpu); | |
412 | if (!node_online(nid)) { | |
413 | err = mem_online_node(nid); | |
414 | if (err) | |
415 | return err; | |
416 | } | |
417 | ||
418 | pgdat = NODE_DATA(nid); | |
419 | if (!pgdat) { | |
420 | printk(KERN_ERR | |
421 | "Can't online cpu %d due to NULL pgdat\n", cpu); | |
422 | return -ENOMEM; | |
423 | } | |
424 | ||
4eaf3f64 HL |
425 | if (pgdat->node_zonelists->_zonerefs->zone == NULL) { |
426 | mutex_lock(&zonelists_mutex); | |
9adb62a5 | 427 | build_all_zonelists(NULL, NULL); |
4eaf3f64 HL |
428 | mutex_unlock(&zonelists_mutex); |
429 | } | |
cf23422b | 430 | #endif |
431 | ||
d221938c | 432 | cpu_maps_update_begin(); |
e761b772 MK |
433 | |
434 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 435 | err = -EBUSY; |
e761b772 MK |
436 | goto out; |
437 | } | |
438 | ||
439 | err = _cpu_up(cpu, 0); | |
440 | ||
e761b772 | 441 | out: |
d221938c | 442 | cpu_maps_update_done(); |
e3920fb4 RW |
443 | return err; |
444 | } | |
a513f6ba | 445 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 446 | |
f3de4be9 | 447 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 448 | static cpumask_var_t frozen_cpus; |
e3920fb4 RW |
449 | |
450 | int disable_nonboot_cpus(void) | |
451 | { | |
e9a5f426 | 452 | int cpu, first_cpu, error = 0; |
e3920fb4 | 453 | |
d221938c | 454 | cpu_maps_update_begin(); |
e0b582ec | 455 | first_cpu = cpumask_first(cpu_online_mask); |
9ee349ad XF |
456 | /* |
457 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
458 | * with the userspace trying to use the CPU hotplug at the same time |
459 | */ | |
e0b582ec | 460 | cpumask_clear(frozen_cpus); |
6ad4c188 | 461 | |
e3920fb4 RW |
462 | printk("Disabling non-boot CPUs ...\n"); |
463 | for_each_online_cpu(cpu) { | |
464 | if (cpu == first_cpu) | |
465 | continue; | |
8bb78442 | 466 | error = _cpu_down(cpu, 1); |
feae3203 | 467 | if (!error) |
e0b582ec | 468 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 469 | else { |
e3920fb4 RW |
470 | printk(KERN_ERR "Error taking CPU%d down: %d\n", |
471 | cpu, error); | |
472 | break; | |
473 | } | |
474 | } | |
86886e55 | 475 | |
e3920fb4 RW |
476 | if (!error) { |
477 | BUG_ON(num_online_cpus() > 1); | |
478 | /* Make sure the CPUs won't be enabled by someone else */ | |
479 | cpu_hotplug_disabled = 1; | |
480 | } else { | |
e1d9fd2e | 481 | printk(KERN_ERR "Non-boot CPUs are not disabled\n"); |
e3920fb4 | 482 | } |
d221938c | 483 | cpu_maps_update_done(); |
e3920fb4 RW |
484 | return error; |
485 | } | |
486 | ||
d0af9eed SS |
487 | void __weak arch_enable_nonboot_cpus_begin(void) |
488 | { | |
489 | } | |
490 | ||
491 | void __weak arch_enable_nonboot_cpus_end(void) | |
492 | { | |
493 | } | |
494 | ||
fa7303e2 | 495 | void __ref enable_nonboot_cpus(void) |
e3920fb4 RW |
496 | { |
497 | int cpu, error; | |
498 | ||
499 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 500 | cpu_maps_update_begin(); |
e3920fb4 | 501 | cpu_hotplug_disabled = 0; |
e0b582ec | 502 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 503 | goto out; |
e3920fb4 | 504 | |
4d51985e | 505 | printk(KERN_INFO "Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
506 | |
507 | arch_enable_nonboot_cpus_begin(); | |
508 | ||
e0b582ec | 509 | for_each_cpu(cpu, frozen_cpus) { |
8bb78442 | 510 | error = _cpu_up(cpu, 1); |
e3920fb4 | 511 | if (!error) { |
4d51985e | 512 | printk(KERN_INFO "CPU%d is up\n", cpu); |
e3920fb4 RW |
513 | continue; |
514 | } | |
1d64b9cb | 515 | printk(KERN_WARNING "Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 516 | } |
d0af9eed SS |
517 | |
518 | arch_enable_nonboot_cpus_end(); | |
519 | ||
e0b582ec | 520 | cpumask_clear(frozen_cpus); |
1d64b9cb | 521 | out: |
d221938c | 522 | cpu_maps_update_done(); |
1da177e4 | 523 | } |
e0b582ec | 524 | |
d7268a31 | 525 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
526 | { |
527 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
528 | return -ENOMEM; | |
529 | return 0; | |
530 | } | |
531 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa SB |
532 | |
533 | /* | |
534 | * Prevent regular CPU hotplug from racing with the freezer, by disabling CPU | |
535 | * hotplug when tasks are about to be frozen. Also, don't allow the freezer | |
536 | * to continue until any currently running CPU hotplug operation gets | |
537 | * completed. | |
538 | * To modify the 'cpu_hotplug_disabled' flag, we need to acquire the | |
539 | * 'cpu_add_remove_lock'. And this same lock is also taken by the regular | |
540 | * CPU hotplug path and released only after it is complete. Thus, we | |
541 | * (and hence the freezer) will block here until any currently running CPU | |
542 | * hotplug operation gets completed. | |
543 | */ | |
544 | void cpu_hotplug_disable_before_freeze(void) | |
545 | { | |
546 | cpu_maps_update_begin(); | |
547 | cpu_hotplug_disabled = 1; | |
548 | cpu_maps_update_done(); | |
549 | } | |
550 | ||
551 | ||
552 | /* | |
553 | * When tasks have been thawed, re-enable regular CPU hotplug (which had been | |
554 | * disabled while beginning to freeze tasks). | |
555 | */ | |
556 | void cpu_hotplug_enable_after_thaw(void) | |
557 | { | |
558 | cpu_maps_update_begin(); | |
559 | cpu_hotplug_disabled = 0; | |
560 | cpu_maps_update_done(); | |
561 | } | |
562 | ||
563 | /* | |
564 | * When callbacks for CPU hotplug notifications are being executed, we must | |
565 | * ensure that the state of the system with respect to the tasks being frozen | |
566 | * or not, as reported by the notification, remains unchanged *throughout the | |
567 | * duration* of the execution of the callbacks. | |
568 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
569 | * | |
570 | * This synchronization is implemented by mutually excluding regular CPU | |
571 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
572 | * Hibernate notifications. | |
573 | */ | |
574 | static int | |
575 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
576 | unsigned long action, void *ptr) | |
577 | { | |
578 | switch (action) { | |
579 | ||
580 | case PM_SUSPEND_PREPARE: | |
581 | case PM_HIBERNATION_PREPARE: | |
582 | cpu_hotplug_disable_before_freeze(); | |
583 | break; | |
584 | ||
585 | case PM_POST_SUSPEND: | |
586 | case PM_POST_HIBERNATION: | |
587 | cpu_hotplug_enable_after_thaw(); | |
588 | break; | |
589 | ||
590 | default: | |
591 | return NOTIFY_DONE; | |
592 | } | |
593 | ||
594 | return NOTIFY_OK; | |
595 | } | |
596 | ||
597 | ||
d7268a31 | 598 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa SB |
599 | { |
600 | pm_notifier(cpu_hotplug_pm_callback, 0); | |
601 | return 0; | |
602 | } | |
603 | core_initcall(cpu_hotplug_pm_sync_init); | |
604 | ||
f3de4be9 | 605 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 606 | |
e545a614 MS |
607 | /** |
608 | * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers | |
609 | * @cpu: cpu that just started | |
610 | * | |
611 | * This function calls the cpu_chain notifiers with CPU_STARTING. | |
612 | * It must be called by the arch code on the new cpu, before the new cpu | |
613 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
614 | */ | |
84196414 | 615 | void __cpuinit notify_cpu_starting(unsigned int cpu) |
e545a614 MS |
616 | { |
617 | unsigned long val = CPU_STARTING; | |
618 | ||
619 | #ifdef CONFIG_PM_SLEEP_SMP | |
e0b582ec | 620 | if (frozen_cpus != NULL && cpumask_test_cpu(cpu, frozen_cpus)) |
e545a614 MS |
621 | val = CPU_STARTING_FROZEN; |
622 | #endif /* CONFIG_PM_SLEEP_SMP */ | |
e9fb7631 | 623 | cpu_notify(val, (void *)(long)cpu); |
e545a614 MS |
624 | } |
625 | ||
68f4f1ec | 626 | #endif /* CONFIG_SMP */ |
b8d317d1 | 627 | |
e56b3bc7 LT |
628 | /* |
629 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
630 | * represents all NR_CPUS bits binary values of 1<<nr. | |
631 | * | |
e0b582ec | 632 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
633 | * mask value that has a single bit set only. |
634 | */ | |
b8d317d1 | 635 | |
e56b3bc7 | 636 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 637 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
638 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
639 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
640 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 641 | |
e56b3bc7 LT |
642 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
643 | ||
644 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
645 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
646 | #if BITS_PER_LONG > 32 | |
647 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
648 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
649 | #endif |
650 | }; | |
e56b3bc7 | 651 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
652 | |
653 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
654 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
655 | |
656 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
657 | static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly | |
658 | = CPU_BITS_ALL; | |
659 | #else | |
660 | static DECLARE_BITMAP(cpu_possible_bits, CONFIG_NR_CPUS) __read_mostly; | |
661 | #endif | |
662 | const struct cpumask *const cpu_possible_mask = to_cpumask(cpu_possible_bits); | |
663 | EXPORT_SYMBOL(cpu_possible_mask); | |
664 | ||
665 | static DECLARE_BITMAP(cpu_online_bits, CONFIG_NR_CPUS) __read_mostly; | |
666 | const struct cpumask *const cpu_online_mask = to_cpumask(cpu_online_bits); | |
667 | EXPORT_SYMBOL(cpu_online_mask); | |
668 | ||
669 | static DECLARE_BITMAP(cpu_present_bits, CONFIG_NR_CPUS) __read_mostly; | |
670 | const struct cpumask *const cpu_present_mask = to_cpumask(cpu_present_bits); | |
671 | EXPORT_SYMBOL(cpu_present_mask); | |
672 | ||
673 | static DECLARE_BITMAP(cpu_active_bits, CONFIG_NR_CPUS) __read_mostly; | |
674 | const struct cpumask *const cpu_active_mask = to_cpumask(cpu_active_bits); | |
675 | EXPORT_SYMBOL(cpu_active_mask); | |
3fa41520 RR |
676 | |
677 | void set_cpu_possible(unsigned int cpu, bool possible) | |
678 | { | |
679 | if (possible) | |
680 | cpumask_set_cpu(cpu, to_cpumask(cpu_possible_bits)); | |
681 | else | |
682 | cpumask_clear_cpu(cpu, to_cpumask(cpu_possible_bits)); | |
683 | } | |
684 | ||
685 | void set_cpu_present(unsigned int cpu, bool present) | |
686 | { | |
687 | if (present) | |
688 | cpumask_set_cpu(cpu, to_cpumask(cpu_present_bits)); | |
689 | else | |
690 | cpumask_clear_cpu(cpu, to_cpumask(cpu_present_bits)); | |
691 | } | |
692 | ||
693 | void set_cpu_online(unsigned int cpu, bool online) | |
694 | { | |
695 | if (online) | |
696 | cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits)); | |
697 | else | |
698 | cpumask_clear_cpu(cpu, to_cpumask(cpu_online_bits)); | |
699 | } | |
700 | ||
701 | void set_cpu_active(unsigned int cpu, bool active) | |
702 | { | |
703 | if (active) | |
704 | cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits)); | |
705 | else | |
706 | cpumask_clear_cpu(cpu, to_cpumask(cpu_active_bits)); | |
707 | } | |
708 | ||
709 | void init_cpu_present(const struct cpumask *src) | |
710 | { | |
711 | cpumask_copy(to_cpumask(cpu_present_bits), src); | |
712 | } | |
713 | ||
714 | void init_cpu_possible(const struct cpumask *src) | |
715 | { | |
716 | cpumask_copy(to_cpumask(cpu_possible_bits), src); | |
717 | } | |
718 | ||
719 | void init_cpu_online(const struct cpumask *src) | |
720 | { | |
721 | cpumask_copy(to_cpumask(cpu_online_bits), src); | |
722 | } |