]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* CPU control. |
2 | * (C) 2001, 2002, 2003, 2004 Rusty Russell | |
3 | * | |
4 | * This code is licenced under the GPL. | |
5 | */ | |
6 | #include <linux/proc_fs.h> | |
7 | #include <linux/smp.h> | |
8 | #include <linux/init.h> | |
9 | #include <linux/notifier.h> | |
10 | #include <linux/sched.h> | |
11 | #include <linux/unistd.h> | |
12 | #include <linux/cpu.h> | |
cb79295e AV |
13 | #include <linux/oom.h> |
14 | #include <linux/rcupdate.h> | |
9984de1a | 15 | #include <linux/export.h> |
e4cc2f87 | 16 | #include <linux/bug.h> |
1da177e4 LT |
17 | #include <linux/kthread.h> |
18 | #include <linux/stop_machine.h> | |
81615b62 | 19 | #include <linux/mutex.h> |
5a0e3ad6 | 20 | #include <linux/gfp.h> |
79cfbdfa | 21 | #include <linux/suspend.h> |
a19423b9 | 22 | #include <linux/lockdep.h> |
345527b1 | 23 | #include <linux/tick.h> |
a8994181 | 24 | #include <linux/irq.h> |
cff7d378 | 25 | |
bb3632c6 | 26 | #include <trace/events/power.h> |
cff7d378 TG |
27 | #define CREATE_TRACE_POINTS |
28 | #include <trace/events/cpuhp.h> | |
1da177e4 | 29 | |
38498a67 TG |
30 | #include "smpboot.h" |
31 | ||
cff7d378 TG |
32 | /** |
33 | * cpuhp_cpu_state - Per cpu hotplug state storage | |
34 | * @state: The current cpu state | |
35 | * @target: The target state | |
36 | */ | |
37 | struct cpuhp_cpu_state { | |
38 | enum cpuhp_state state; | |
39 | enum cpuhp_state target; | |
40 | }; | |
41 | ||
42 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state); | |
43 | ||
44 | /** | |
45 | * cpuhp_step - Hotplug state machine step | |
46 | * @name: Name of the step | |
47 | * @startup: Startup function of the step | |
48 | * @teardown: Teardown function of the step | |
49 | * @skip_onerr: Do not invoke the functions on error rollback | |
50 | * Will go away once the notifiers are gone | |
51 | */ | |
52 | struct cpuhp_step { | |
53 | const char *name; | |
54 | int (*startup)(unsigned int cpu); | |
55 | int (*teardown)(unsigned int cpu); | |
56 | bool skip_onerr; | |
57 | }; | |
58 | ||
98f8cdce | 59 | static DEFINE_MUTEX(cpuhp_state_mutex); |
cff7d378 | 60 | static struct cpuhp_step cpuhp_bp_states[]; |
4baa0afc | 61 | static struct cpuhp_step cpuhp_ap_states[]; |
cff7d378 TG |
62 | |
63 | /** | |
64 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state | |
65 | * @cpu: The cpu for which the callback should be invoked | |
66 | * @step: The step in the state machine | |
67 | * @cb: The callback function to invoke | |
68 | * | |
69 | * Called from cpu hotplug and from the state register machinery | |
70 | */ | |
71 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state step, | |
72 | int (*cb)(unsigned int)) | |
73 | { | |
74 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
75 | int ret = 0; | |
76 | ||
77 | if (cb) { | |
78 | trace_cpuhp_enter(cpu, st->target, step, cb); | |
79 | ret = cb(cpu); | |
80 | trace_cpuhp_exit(cpu, st->state, step, ret); | |
81 | } | |
82 | return ret; | |
83 | } | |
84 | ||
98a79d6a | 85 | #ifdef CONFIG_SMP |
b3199c02 | 86 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 87 | static DEFINE_MUTEX(cpu_add_remove_lock); |
090e77c3 TG |
88 | bool cpuhp_tasks_frozen; |
89 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
1da177e4 | 90 | |
79a6cdeb | 91 | /* |
93ae4f97 SB |
92 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
93 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
94 | * The APIs cpu_notifier_register_begin/done() must be used to protect CPU | |
95 | * hotplug callback (un)registration performed using __register_cpu_notifier() | |
96 | * or __unregister_cpu_notifier(). | |
79a6cdeb LJ |
97 | */ |
98 | void cpu_maps_update_begin(void) | |
99 | { | |
100 | mutex_lock(&cpu_add_remove_lock); | |
101 | } | |
93ae4f97 | 102 | EXPORT_SYMBOL(cpu_notifier_register_begin); |
79a6cdeb LJ |
103 | |
104 | void cpu_maps_update_done(void) | |
105 | { | |
106 | mutex_unlock(&cpu_add_remove_lock); | |
107 | } | |
93ae4f97 | 108 | EXPORT_SYMBOL(cpu_notifier_register_done); |
79a6cdeb | 109 | |
5c113fbe | 110 | static RAW_NOTIFIER_HEAD(cpu_chain); |
1da177e4 | 111 | |
e3920fb4 RW |
112 | /* If set, cpu_up and cpu_down will return -EBUSY and do nothing. |
113 | * Should always be manipulated under cpu_add_remove_lock | |
114 | */ | |
115 | static int cpu_hotplug_disabled; | |
116 | ||
79a6cdeb LJ |
117 | #ifdef CONFIG_HOTPLUG_CPU |
118 | ||
d221938c GS |
119 | static struct { |
120 | struct task_struct *active_writer; | |
87af9e7f DH |
121 | /* wait queue to wake up the active_writer */ |
122 | wait_queue_head_t wq; | |
123 | /* verifies that no writer will get active while readers are active */ | |
124 | struct mutex lock; | |
d221938c GS |
125 | /* |
126 | * Also blocks the new readers during | |
127 | * an ongoing cpu hotplug operation. | |
128 | */ | |
87af9e7f | 129 | atomic_t refcount; |
a19423b9 GS |
130 | |
131 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
132 | struct lockdep_map dep_map; | |
133 | #endif | |
31950eb6 LT |
134 | } cpu_hotplug = { |
135 | .active_writer = NULL, | |
87af9e7f | 136 | .wq = __WAIT_QUEUE_HEAD_INITIALIZER(cpu_hotplug.wq), |
31950eb6 | 137 | .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock), |
a19423b9 GS |
138 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
139 | .dep_map = {.name = "cpu_hotplug.lock" }, | |
140 | #endif | |
31950eb6 | 141 | }; |
d221938c | 142 | |
a19423b9 GS |
143 | /* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */ |
144 | #define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map) | |
dd56af42 PM |
145 | #define cpuhp_lock_acquire_tryread() \ |
146 | lock_map_acquire_tryread(&cpu_hotplug.dep_map) | |
a19423b9 GS |
147 | #define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map) |
148 | #define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map) | |
149 | ||
62db99f4 | 150 | |
86ef5c9a | 151 | void get_online_cpus(void) |
a9d9baa1 | 152 | { |
d221938c GS |
153 | might_sleep(); |
154 | if (cpu_hotplug.active_writer == current) | |
aa953877 | 155 | return; |
a19423b9 | 156 | cpuhp_lock_acquire_read(); |
d221938c | 157 | mutex_lock(&cpu_hotplug.lock); |
87af9e7f | 158 | atomic_inc(&cpu_hotplug.refcount); |
d221938c | 159 | mutex_unlock(&cpu_hotplug.lock); |
a9d9baa1 | 160 | } |
86ef5c9a | 161 | EXPORT_SYMBOL_GPL(get_online_cpus); |
90d45d17 | 162 | |
86ef5c9a | 163 | void put_online_cpus(void) |
a9d9baa1 | 164 | { |
87af9e7f DH |
165 | int refcount; |
166 | ||
d221938c | 167 | if (cpu_hotplug.active_writer == current) |
aa953877 | 168 | return; |
075663d1 | 169 | |
87af9e7f DH |
170 | refcount = atomic_dec_return(&cpu_hotplug.refcount); |
171 | if (WARN_ON(refcount < 0)) /* try to fix things up */ | |
172 | atomic_inc(&cpu_hotplug.refcount); | |
173 | ||
174 | if (refcount <= 0 && waitqueue_active(&cpu_hotplug.wq)) | |
175 | wake_up(&cpu_hotplug.wq); | |
075663d1 | 176 | |
a19423b9 | 177 | cpuhp_lock_release(); |
d221938c | 178 | |
a9d9baa1 | 179 | } |
86ef5c9a | 180 | EXPORT_SYMBOL_GPL(put_online_cpus); |
a9d9baa1 | 181 | |
d221938c GS |
182 | /* |
183 | * This ensures that the hotplug operation can begin only when the | |
184 | * refcount goes to zero. | |
185 | * | |
186 | * Note that during a cpu-hotplug operation, the new readers, if any, | |
187 | * will be blocked by the cpu_hotplug.lock | |
188 | * | |
d2ba7e2a ON |
189 | * Since cpu_hotplug_begin() is always called after invoking |
190 | * cpu_maps_update_begin(), we can be sure that only one writer is active. | |
d221938c GS |
191 | * |
192 | * Note that theoretically, there is a possibility of a livelock: | |
193 | * - Refcount goes to zero, last reader wakes up the sleeping | |
194 | * writer. | |
195 | * - Last reader unlocks the cpu_hotplug.lock. | |
196 | * - A new reader arrives at this moment, bumps up the refcount. | |
197 | * - The writer acquires the cpu_hotplug.lock finds the refcount | |
198 | * non zero and goes to sleep again. | |
199 | * | |
200 | * However, this is very difficult to achieve in practice since | |
86ef5c9a | 201 | * get_online_cpus() not an api which is called all that often. |
d221938c GS |
202 | * |
203 | */ | |
b9d10be7 | 204 | void cpu_hotplug_begin(void) |
d221938c | 205 | { |
87af9e7f | 206 | DEFINE_WAIT(wait); |
d2ba7e2a | 207 | |
87af9e7f | 208 | cpu_hotplug.active_writer = current; |
a19423b9 | 209 | cpuhp_lock_acquire(); |
87af9e7f | 210 | |
d2ba7e2a ON |
211 | for (;;) { |
212 | mutex_lock(&cpu_hotplug.lock); | |
87af9e7f DH |
213 | prepare_to_wait(&cpu_hotplug.wq, &wait, TASK_UNINTERRUPTIBLE); |
214 | if (likely(!atomic_read(&cpu_hotplug.refcount))) | |
215 | break; | |
d221938c GS |
216 | mutex_unlock(&cpu_hotplug.lock); |
217 | schedule(); | |
d221938c | 218 | } |
87af9e7f | 219 | finish_wait(&cpu_hotplug.wq, &wait); |
d221938c GS |
220 | } |
221 | ||
b9d10be7 | 222 | void cpu_hotplug_done(void) |
d221938c GS |
223 | { |
224 | cpu_hotplug.active_writer = NULL; | |
225 | mutex_unlock(&cpu_hotplug.lock); | |
a19423b9 | 226 | cpuhp_lock_release(); |
d221938c | 227 | } |
79a6cdeb | 228 | |
16e53dbf SB |
229 | /* |
230 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
231 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
232 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
233 | * hotplug path before performing hotplug operations. So acquiring that lock | |
234 | * guarantees mutual exclusion from any currently running hotplug operations. | |
235 | */ | |
236 | void cpu_hotplug_disable(void) | |
237 | { | |
238 | cpu_maps_update_begin(); | |
89af7ba5 | 239 | cpu_hotplug_disabled++; |
16e53dbf SB |
240 | cpu_maps_update_done(); |
241 | } | |
32145c46 | 242 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
16e53dbf SB |
243 | |
244 | void cpu_hotplug_enable(void) | |
245 | { | |
246 | cpu_maps_update_begin(); | |
89af7ba5 | 247 | WARN_ON(--cpu_hotplug_disabled < 0); |
16e53dbf SB |
248 | cpu_maps_update_done(); |
249 | } | |
32145c46 | 250 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
b9d10be7 | 251 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 252 | |
1da177e4 | 253 | /* Need to know about CPUs going up/down? */ |
71cf5aee | 254 | int register_cpu_notifier(struct notifier_block *nb) |
1da177e4 | 255 | { |
bd5349cf | 256 | int ret; |
d221938c | 257 | cpu_maps_update_begin(); |
bd5349cf | 258 | ret = raw_notifier_chain_register(&cpu_chain, nb); |
d221938c | 259 | cpu_maps_update_done(); |
bd5349cf | 260 | return ret; |
1da177e4 | 261 | } |
65edc68c | 262 | |
71cf5aee | 263 | int __register_cpu_notifier(struct notifier_block *nb) |
93ae4f97 SB |
264 | { |
265 | return raw_notifier_chain_register(&cpu_chain, nb); | |
266 | } | |
267 | ||
090e77c3 | 268 | static int __cpu_notify(unsigned long val, unsigned int cpu, int nr_to_call, |
e9fb7631 AM |
269 | int *nr_calls) |
270 | { | |
090e77c3 TG |
271 | unsigned long mod = cpuhp_tasks_frozen ? CPU_TASKS_FROZEN : 0; |
272 | void *hcpu = (void *)(long)cpu; | |
273 | ||
e6bde73b AM |
274 | int ret; |
275 | ||
090e77c3 | 276 | ret = __raw_notifier_call_chain(&cpu_chain, val | mod, hcpu, nr_to_call, |
e9fb7631 | 277 | nr_calls); |
e6bde73b AM |
278 | |
279 | return notifier_to_errno(ret); | |
e9fb7631 AM |
280 | } |
281 | ||
090e77c3 | 282 | static int cpu_notify(unsigned long val, unsigned int cpu) |
e9fb7631 | 283 | { |
090e77c3 | 284 | return __cpu_notify(val, cpu, -1, NULL); |
e9fb7631 AM |
285 | } |
286 | ||
ba997462 TG |
287 | /* Notifier wrappers for transitioning to state machine */ |
288 | static int notify_prepare(unsigned int cpu) | |
289 | { | |
290 | int nr_calls = 0; | |
291 | int ret; | |
292 | ||
293 | ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls); | |
294 | if (ret) { | |
295 | nr_calls--; | |
296 | printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n", | |
297 | __func__, cpu); | |
298 | __cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL); | |
299 | } | |
300 | return ret; | |
301 | } | |
302 | ||
303 | static int notify_online(unsigned int cpu) | |
304 | { | |
305 | cpu_notify(CPU_ONLINE, cpu); | |
306 | return 0; | |
307 | } | |
308 | ||
4baa0afc TG |
309 | static int notify_starting(unsigned int cpu) |
310 | { | |
311 | cpu_notify(CPU_STARTING, cpu); | |
312 | return 0; | |
313 | } | |
314 | ||
ba997462 TG |
315 | static int bringup_cpu(unsigned int cpu) |
316 | { | |
317 | struct task_struct *idle = idle_thread_get(cpu); | |
318 | int ret; | |
319 | ||
320 | /* Arch-specific enabling code. */ | |
321 | ret = __cpu_up(cpu, idle); | |
322 | if (ret) { | |
323 | cpu_notify(CPU_UP_CANCELED, cpu); | |
324 | return ret; | |
325 | } | |
326 | BUG_ON(!cpu_online(cpu)); | |
327 | return 0; | |
328 | } | |
329 | ||
00b9b0af | 330 | #ifdef CONFIG_HOTPLUG_CPU |
1da177e4 | 331 | EXPORT_SYMBOL(register_cpu_notifier); |
93ae4f97 | 332 | EXPORT_SYMBOL(__register_cpu_notifier); |
1da177e4 | 333 | |
71cf5aee | 334 | void unregister_cpu_notifier(struct notifier_block *nb) |
1da177e4 | 335 | { |
d221938c | 336 | cpu_maps_update_begin(); |
bd5349cf | 337 | raw_notifier_chain_unregister(&cpu_chain, nb); |
d221938c | 338 | cpu_maps_update_done(); |
1da177e4 LT |
339 | } |
340 | EXPORT_SYMBOL(unregister_cpu_notifier); | |
341 | ||
71cf5aee | 342 | void __unregister_cpu_notifier(struct notifier_block *nb) |
93ae4f97 SB |
343 | { |
344 | raw_notifier_chain_unregister(&cpu_chain, nb); | |
345 | } | |
346 | EXPORT_SYMBOL(__unregister_cpu_notifier); | |
347 | ||
e4cc2f87 AV |
348 | /** |
349 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
350 | * @cpu: a CPU id | |
351 | * | |
352 | * This function walks all processes, finds a valid mm struct for each one and | |
353 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
354 | * trivial, there are various non-obvious corner cases, which this function | |
355 | * tries to solve in a safe manner. | |
356 | * | |
357 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
358 | * be called only for an already offlined CPU. | |
359 | */ | |
cb79295e AV |
360 | void clear_tasks_mm_cpumask(int cpu) |
361 | { | |
362 | struct task_struct *p; | |
363 | ||
364 | /* | |
365 | * This function is called after the cpu is taken down and marked | |
366 | * offline, so its not like new tasks will ever get this cpu set in | |
367 | * their mm mask. -- Peter Zijlstra | |
368 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
369 | * full-fledged tasklist_lock. | |
370 | */ | |
e4cc2f87 | 371 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
372 | rcu_read_lock(); |
373 | for_each_process(p) { | |
374 | struct task_struct *t; | |
375 | ||
e4cc2f87 AV |
376 | /* |
377 | * Main thread might exit, but other threads may still have | |
378 | * a valid mm. Find one. | |
379 | */ | |
cb79295e AV |
380 | t = find_lock_task_mm(p); |
381 | if (!t) | |
382 | continue; | |
383 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
384 | task_unlock(t); | |
385 | } | |
386 | rcu_read_unlock(); | |
387 | } | |
388 | ||
b728ca06 | 389 | static inline void check_for_tasks(int dead_cpu) |
1da177e4 | 390 | { |
b728ca06 | 391 | struct task_struct *g, *p; |
1da177e4 | 392 | |
a75a6068 ON |
393 | read_lock(&tasklist_lock); |
394 | for_each_process_thread(g, p) { | |
b728ca06 KT |
395 | if (!p->on_rq) |
396 | continue; | |
397 | /* | |
398 | * We do the check with unlocked task_rq(p)->lock. | |
399 | * Order the reading to do not warn about a task, | |
400 | * which was running on this cpu in the past, and | |
401 | * it's just been woken on another cpu. | |
402 | */ | |
403 | rmb(); | |
404 | if (task_cpu(p) != dead_cpu) | |
405 | continue; | |
406 | ||
407 | pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n", | |
408 | p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags); | |
a75a6068 ON |
409 | } |
410 | read_unlock(&tasklist_lock); | |
1da177e4 LT |
411 | } |
412 | ||
98458172 TG |
413 | static void cpu_notify_nofail(unsigned long val, unsigned int cpu) |
414 | { | |
415 | BUG_ON(cpu_notify(val, cpu)); | |
416 | } | |
417 | ||
418 | static int notify_down_prepare(unsigned int cpu) | |
419 | { | |
420 | int err, nr_calls = 0; | |
421 | ||
422 | err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls); | |
423 | if (err) { | |
424 | nr_calls--; | |
425 | __cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL); | |
426 | pr_warn("%s: attempt to take down CPU %u failed\n", | |
427 | __func__, cpu); | |
428 | } | |
429 | return err; | |
430 | } | |
431 | ||
4baa0afc TG |
432 | static int notify_dying(unsigned int cpu) |
433 | { | |
434 | cpu_notify(CPU_DYING, cpu); | |
435 | return 0; | |
436 | } | |
437 | ||
1da177e4 | 438 | /* Take this CPU down. */ |
71cf5aee | 439 | static int take_cpu_down(void *_param) |
1da177e4 | 440 | { |
4baa0afc TG |
441 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
442 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 443 | int err, cpu = smp_processor_id(); |
1da177e4 | 444 | |
1da177e4 LT |
445 | /* Ensure this CPU doesn't handle any more interrupts. */ |
446 | err = __cpu_disable(); | |
447 | if (err < 0) | |
f3705136 | 448 | return err; |
1da177e4 | 449 | |
4baa0afc TG |
450 | /* Invoke the former CPU_DYING callbacks */ |
451 | for (; st->state > target; st->state--) { | |
452 | struct cpuhp_step *step = cpuhp_ap_states + st->state; | |
453 | ||
454 | cpuhp_invoke_callback(cpu, st->state, step->teardown); | |
455 | } | |
52c063d1 TG |
456 | /* Give up timekeeping duties */ |
457 | tick_handover_do_timer(); | |
14e568e7 | 458 | /* Park the stopper thread */ |
090e77c3 | 459 | stop_machine_park(cpu); |
f3705136 | 460 | return 0; |
1da177e4 LT |
461 | } |
462 | ||
98458172 | 463 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 464 | { |
98458172 | 465 | int err; |
1da177e4 | 466 | |
6acce3ef PZ |
467 | /* |
468 | * By now we've cleared cpu_active_mask, wait for all preempt-disabled | |
469 | * and RCU users of this state to go away such that all new such users | |
470 | * will observe it. | |
471 | * | |
472 | * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might | |
779de6ce | 473 | * not imply sync_sched(), so wait for both. |
106dd5af M |
474 | * |
475 | * Do sync before park smpboot threads to take care the rcu boost case. | |
6acce3ef | 476 | */ |
779de6ce PM |
477 | if (IS_ENABLED(CONFIG_PREEMPT)) |
478 | synchronize_rcu_mult(call_rcu, call_rcu_sched); | |
479 | else | |
480 | synchronize_rcu(); | |
6acce3ef | 481 | |
106dd5af M |
482 | smpboot_park_threads(cpu); |
483 | ||
6acce3ef | 484 | /* |
a8994181 TG |
485 | * Prevent irq alloc/free while the dying cpu reorganizes the |
486 | * interrupt affinities. | |
6acce3ef | 487 | */ |
a8994181 | 488 | irq_lock_sparse(); |
6acce3ef | 489 | |
a8994181 TG |
490 | /* |
491 | * So now all preempt/rcu users must observe !cpu_active(). | |
492 | */ | |
090e77c3 | 493 | err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 494 | if (err) { |
1da177e4 | 495 | /* CPU didn't die: tell everyone. Can't complain. */ |
090e77c3 | 496 | cpu_notify_nofail(CPU_DOWN_FAILED, cpu); |
a8994181 | 497 | irq_unlock_sparse(); |
98458172 | 498 | return err; |
8fa1d7d3 | 499 | } |
04321587 | 500 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 501 | |
48c5ccae PZ |
502 | /* |
503 | * The migration_call() CPU_DYING callback will have removed all | |
504 | * runnable tasks from the cpu, there's only the idle task left now | |
505 | * that the migration thread is done doing the stop_machine thing. | |
51a96c77 PZ |
506 | * |
507 | * Wait for the stop thread to go away. | |
48c5ccae | 508 | */ |
528a25b0 | 509 | while (!per_cpu(cpu_dead_idle, cpu)) |
51a96c77 | 510 | cpu_relax(); |
528a25b0 PM |
511 | smp_mb(); /* Read from cpu_dead_idle before __cpu_die(). */ |
512 | per_cpu(cpu_dead_idle, cpu) = false; | |
1da177e4 | 513 | |
a8994181 TG |
514 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
515 | irq_unlock_sparse(); | |
516 | ||
345527b1 | 517 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
518 | /* This actually kills the CPU. */ |
519 | __cpu_die(cpu); | |
520 | ||
a49b116d | 521 | tick_cleanup_dead_cpu(cpu); |
98458172 TG |
522 | return 0; |
523 | } | |
1da177e4 | 524 | |
98458172 TG |
525 | static int notify_dead(unsigned int cpu) |
526 | { | |
527 | cpu_notify_nofail(CPU_DEAD, cpu); | |
1da177e4 | 528 | check_for_tasks(cpu); |
98458172 TG |
529 | return 0; |
530 | } | |
531 | ||
cff7d378 TG |
532 | #else |
533 | #define notify_down_prepare NULL | |
534 | #define takedown_cpu NULL | |
535 | #define notify_dead NULL | |
4baa0afc | 536 | #define notify_dying NULL |
cff7d378 TG |
537 | #endif |
538 | ||
539 | #ifdef CONFIG_HOTPLUG_CPU | |
540 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) | |
541 | { | |
542 | for (st->state++; st->state < st->target; st->state++) { | |
543 | struct cpuhp_step *step = cpuhp_bp_states + st->state; | |
544 | ||
545 | if (!step->skip_onerr) | |
546 | cpuhp_invoke_callback(cpu, st->state, step->startup); | |
547 | } | |
548 | } | |
549 | ||
98458172 | 550 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
551 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
552 | enum cpuhp_state target) | |
98458172 | 553 | { |
cff7d378 TG |
554 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
555 | int prev_state, ret = 0; | |
556 | bool hasdied = false; | |
98458172 TG |
557 | |
558 | if (num_online_cpus() == 1) | |
559 | return -EBUSY; | |
560 | ||
561 | if (!cpu_online(cpu)) | |
562 | return -EINVAL; | |
563 | ||
564 | cpu_hotplug_begin(); | |
565 | ||
566 | cpuhp_tasks_frozen = tasks_frozen; | |
567 | ||
cff7d378 | 568 | prev_state = st->state; |
af1f4045 | 569 | st->target = target; |
cff7d378 TG |
570 | for (; st->state > st->target; st->state--) { |
571 | struct cpuhp_step *step = cpuhp_bp_states + st->state; | |
98458172 | 572 | |
cff7d378 TG |
573 | ret = cpuhp_invoke_callback(cpu, st->state, step->teardown); |
574 | if (ret) { | |
575 | st->target = prev_state; | |
576 | undo_cpu_down(cpu, st); | |
577 | break; | |
578 | } | |
579 | } | |
580 | hasdied = prev_state != st->state && st->state == CPUHP_OFFLINE; | |
1da177e4 | 581 | |
d221938c | 582 | cpu_hotplug_done(); |
cff7d378 TG |
583 | /* This post dead nonsense must die */ |
584 | if (!ret && hasdied) | |
090e77c3 | 585 | cpu_notify_nofail(CPU_POST_DEAD, cpu); |
cff7d378 | 586 | return ret; |
e3920fb4 RW |
587 | } |
588 | ||
af1f4045 | 589 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 590 | { |
9ea09af3 | 591 | int err; |
e3920fb4 | 592 | |
d221938c | 593 | cpu_maps_update_begin(); |
e761b772 MK |
594 | |
595 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 596 | err = -EBUSY; |
e761b772 MK |
597 | goto out; |
598 | } | |
599 | ||
af1f4045 | 600 | err = _cpu_down(cpu, 0, target); |
e3920fb4 | 601 | |
e761b772 | 602 | out: |
d221938c | 603 | cpu_maps_update_done(); |
1da177e4 LT |
604 | return err; |
605 | } | |
af1f4045 TG |
606 | int cpu_down(unsigned int cpu) |
607 | { | |
608 | return do_cpu_down(cpu, CPUHP_OFFLINE); | |
609 | } | |
b62b8ef9 | 610 | EXPORT_SYMBOL(cpu_down); |
1da177e4 LT |
611 | #endif /*CONFIG_HOTPLUG_CPU*/ |
612 | ||
00df35f9 PM |
613 | /* |
614 | * Unpark per-CPU smpboot kthreads at CPU-online time. | |
615 | */ | |
616 | static int smpboot_thread_call(struct notifier_block *nfb, | |
617 | unsigned long action, void *hcpu) | |
618 | { | |
619 | int cpu = (long)hcpu; | |
620 | ||
621 | switch (action & ~CPU_TASKS_FROZEN) { | |
622 | ||
64eaf974 | 623 | case CPU_DOWN_FAILED: |
00df35f9 PM |
624 | case CPU_ONLINE: |
625 | smpboot_unpark_threads(cpu); | |
626 | break; | |
627 | ||
628 | default: | |
629 | break; | |
630 | } | |
631 | ||
632 | return NOTIFY_OK; | |
633 | } | |
634 | ||
635 | static struct notifier_block smpboot_thread_notifier = { | |
636 | .notifier_call = smpboot_thread_call, | |
637 | .priority = CPU_PRI_SMPBOOT, | |
638 | }; | |
639 | ||
927da9df | 640 | void smpboot_thread_init(void) |
00df35f9 PM |
641 | { |
642 | register_cpu_notifier(&smpboot_thread_notifier); | |
643 | } | |
644 | ||
4baa0afc TG |
645 | /** |
646 | * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers | |
647 | * @cpu: cpu that just started | |
648 | * | |
649 | * This function calls the cpu_chain notifiers with CPU_STARTING. | |
650 | * It must be called by the arch code on the new cpu, before the new cpu | |
651 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
652 | */ | |
653 | void notify_cpu_starting(unsigned int cpu) | |
654 | { | |
655 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
656 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
657 | ||
658 | while (st->state < target) { | |
659 | struct cpuhp_step *step; | |
660 | ||
661 | st->state++; | |
662 | step = cpuhp_ap_states + st->state; | |
663 | cpuhp_invoke_callback(cpu, st->state, step->startup); | |
664 | } | |
665 | } | |
666 | ||
cff7d378 TG |
667 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) |
668 | { | |
669 | for (st->state--; st->state > st->target; st->state--) { | |
670 | struct cpuhp_step *step = cpuhp_bp_states + st->state; | |
671 | ||
672 | if (!step->skip_onerr) | |
673 | cpuhp_invoke_callback(cpu, st->state, step->teardown); | |
674 | } | |
675 | } | |
676 | ||
e3920fb4 | 677 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 678 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 679 | { |
cff7d378 | 680 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 681 | struct task_struct *idle; |
cff7d378 | 682 | int prev_state, ret = 0; |
1da177e4 | 683 | |
d221938c | 684 | cpu_hotplug_begin(); |
38498a67 | 685 | |
5e5041f3 YI |
686 | if (cpu_online(cpu) || !cpu_present(cpu)) { |
687 | ret = -EINVAL; | |
688 | goto out; | |
689 | } | |
690 | ||
cff7d378 | 691 | /* Let it fail before we try to bring the cpu up */ |
3bb5d2ee SS |
692 | idle = idle_thread_get(cpu); |
693 | if (IS_ERR(idle)) { | |
694 | ret = PTR_ERR(idle); | |
38498a67 | 695 | goto out; |
3bb5d2ee | 696 | } |
38498a67 | 697 | |
ba997462 TG |
698 | cpuhp_tasks_frozen = tasks_frozen; |
699 | ||
cff7d378 | 700 | prev_state = st->state; |
af1f4045 | 701 | st->target = target; |
cff7d378 TG |
702 | while (st->state < st->target) { |
703 | struct cpuhp_step *step; | |
704 | ||
705 | st->state++; | |
706 | step = cpuhp_bp_states + st->state; | |
707 | ret = cpuhp_invoke_callback(cpu, st->state, step->startup); | |
708 | if (ret) { | |
709 | st->target = prev_state; | |
710 | undo_cpu_up(cpu, st); | |
711 | break; | |
712 | } | |
713 | } | |
38498a67 | 714 | out: |
d221938c | 715 | cpu_hotplug_done(); |
e3920fb4 RW |
716 | return ret; |
717 | } | |
718 | ||
af1f4045 | 719 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
720 | { |
721 | int err = 0; | |
cf23422b | 722 | |
e0b582ec | 723 | if (!cpu_possible(cpu)) { |
84117da5 FF |
724 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
725 | cpu); | |
87d5e023 | 726 | #if defined(CONFIG_IA64) |
84117da5 | 727 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
728 | #endif |
729 | return -EINVAL; | |
730 | } | |
e3920fb4 | 731 | |
01b0f197 TK |
732 | err = try_online_node(cpu_to_node(cpu)); |
733 | if (err) | |
734 | return err; | |
cf23422b | 735 | |
d221938c | 736 | cpu_maps_update_begin(); |
e761b772 MK |
737 | |
738 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 739 | err = -EBUSY; |
e761b772 MK |
740 | goto out; |
741 | } | |
742 | ||
af1f4045 | 743 | err = _cpu_up(cpu, 0, target); |
e761b772 | 744 | out: |
d221938c | 745 | cpu_maps_update_done(); |
e3920fb4 RW |
746 | return err; |
747 | } | |
af1f4045 TG |
748 | |
749 | int cpu_up(unsigned int cpu) | |
750 | { | |
751 | return do_cpu_up(cpu, CPUHP_ONLINE); | |
752 | } | |
a513f6ba | 753 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 754 | |
f3de4be9 | 755 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 756 | static cpumask_var_t frozen_cpus; |
e3920fb4 RW |
757 | |
758 | int disable_nonboot_cpus(void) | |
759 | { | |
e9a5f426 | 760 | int cpu, first_cpu, error = 0; |
e3920fb4 | 761 | |
d221938c | 762 | cpu_maps_update_begin(); |
e0b582ec | 763 | first_cpu = cpumask_first(cpu_online_mask); |
9ee349ad XF |
764 | /* |
765 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
766 | * with the userspace trying to use the CPU hotplug at the same time |
767 | */ | |
e0b582ec | 768 | cpumask_clear(frozen_cpus); |
6ad4c188 | 769 | |
84117da5 | 770 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 RW |
771 | for_each_online_cpu(cpu) { |
772 | if (cpu == first_cpu) | |
773 | continue; | |
bb3632c6 | 774 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 775 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 776 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 777 | if (!error) |
e0b582ec | 778 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 779 | else { |
84117da5 | 780 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
781 | break; |
782 | } | |
783 | } | |
86886e55 | 784 | |
89af7ba5 | 785 | if (!error) |
e3920fb4 | 786 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 787 | else |
84117da5 | 788 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
789 | |
790 | /* | |
791 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
792 | * this even in case of failure as all disable_nonboot_cpus() users are | |
793 | * supposed to do enable_nonboot_cpus() on the failure path. | |
794 | */ | |
795 | cpu_hotplug_disabled++; | |
796 | ||
d221938c | 797 | cpu_maps_update_done(); |
e3920fb4 RW |
798 | return error; |
799 | } | |
800 | ||
d0af9eed SS |
801 | void __weak arch_enable_nonboot_cpus_begin(void) |
802 | { | |
803 | } | |
804 | ||
805 | void __weak arch_enable_nonboot_cpus_end(void) | |
806 | { | |
807 | } | |
808 | ||
71cf5aee | 809 | void enable_nonboot_cpus(void) |
e3920fb4 RW |
810 | { |
811 | int cpu, error; | |
812 | ||
813 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 814 | cpu_maps_update_begin(); |
89af7ba5 | 815 | WARN_ON(--cpu_hotplug_disabled < 0); |
e0b582ec | 816 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 817 | goto out; |
e3920fb4 | 818 | |
84117da5 | 819 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
820 | |
821 | arch_enable_nonboot_cpus_begin(); | |
822 | ||
e0b582ec | 823 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 824 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 825 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 826 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 827 | if (!error) { |
84117da5 | 828 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
829 | continue; |
830 | } | |
84117da5 | 831 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 832 | } |
d0af9eed SS |
833 | |
834 | arch_enable_nonboot_cpus_end(); | |
835 | ||
e0b582ec | 836 | cpumask_clear(frozen_cpus); |
1d64b9cb | 837 | out: |
d221938c | 838 | cpu_maps_update_done(); |
1da177e4 | 839 | } |
e0b582ec | 840 | |
d7268a31 | 841 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
842 | { |
843 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
844 | return -ENOMEM; | |
845 | return 0; | |
846 | } | |
847 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 848 | |
79cfbdfa SB |
849 | /* |
850 | * When callbacks for CPU hotplug notifications are being executed, we must | |
851 | * ensure that the state of the system with respect to the tasks being frozen | |
852 | * or not, as reported by the notification, remains unchanged *throughout the | |
853 | * duration* of the execution of the callbacks. | |
854 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
855 | * | |
856 | * This synchronization is implemented by mutually excluding regular CPU | |
857 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
858 | * Hibernate notifications. | |
859 | */ | |
860 | static int | |
861 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
862 | unsigned long action, void *ptr) | |
863 | { | |
864 | switch (action) { | |
865 | ||
866 | case PM_SUSPEND_PREPARE: | |
867 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 868 | cpu_hotplug_disable(); |
79cfbdfa SB |
869 | break; |
870 | ||
871 | case PM_POST_SUSPEND: | |
872 | case PM_POST_HIBERNATION: | |
16e53dbf | 873 | cpu_hotplug_enable(); |
79cfbdfa SB |
874 | break; |
875 | ||
876 | default: | |
877 | return NOTIFY_DONE; | |
878 | } | |
879 | ||
880 | return NOTIFY_OK; | |
881 | } | |
882 | ||
883 | ||
d7268a31 | 884 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 885 | { |
6e32d479 FY |
886 | /* |
887 | * cpu_hotplug_pm_callback has higher priority than x86 | |
888 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
889 | * to disable cpu hotplug to avoid cpu hotplug race. | |
890 | */ | |
79cfbdfa SB |
891 | pm_notifier(cpu_hotplug_pm_callback, 0); |
892 | return 0; | |
893 | } | |
894 | core_initcall(cpu_hotplug_pm_sync_init); | |
895 | ||
f3de4be9 | 896 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec MK |
897 | |
898 | #endif /* CONFIG_SMP */ | |
b8d317d1 | 899 | |
cff7d378 TG |
900 | /* Boot processor state steps */ |
901 | static struct cpuhp_step cpuhp_bp_states[] = { | |
902 | [CPUHP_OFFLINE] = { | |
903 | .name = "offline", | |
904 | .startup = NULL, | |
905 | .teardown = NULL, | |
906 | }, | |
907 | #ifdef CONFIG_SMP | |
908 | [CPUHP_CREATE_THREADS]= { | |
909 | .name = "threads:create", | |
910 | .startup = smpboot_create_threads, | |
911 | .teardown = NULL, | |
912 | }, | |
913 | [CPUHP_NOTIFY_PREPARE] = { | |
914 | .name = "notify:prepare", | |
915 | .startup = notify_prepare, | |
916 | .teardown = notify_dead, | |
917 | .skip_onerr = true, | |
918 | }, | |
919 | [CPUHP_BRINGUP_CPU] = { | |
920 | .name = "cpu:bringup", | |
921 | .startup = bringup_cpu, | |
4baa0afc TG |
922 | .teardown = NULL, |
923 | }, | |
924 | [CPUHP_TEARDOWN_CPU] = { | |
925 | .name = "cpu:teardown", | |
926 | .startup = NULL, | |
cff7d378 | 927 | .teardown = takedown_cpu, |
cff7d378 TG |
928 | }, |
929 | [CPUHP_NOTIFY_ONLINE] = { | |
930 | .name = "notify:online", | |
931 | .startup = notify_online, | |
932 | .teardown = notify_down_prepare, | |
933 | }, | |
934 | #endif | |
935 | [CPUHP_ONLINE] = { | |
936 | .name = "online", | |
937 | .startup = NULL, | |
938 | .teardown = NULL, | |
939 | }, | |
940 | }; | |
941 | ||
4baa0afc TG |
942 | /* Application processor state steps */ |
943 | static struct cpuhp_step cpuhp_ap_states[] = { | |
944 | #ifdef CONFIG_SMP | |
945 | [CPUHP_AP_NOTIFY_STARTING] = { | |
946 | .name = "notify:starting", | |
947 | .startup = notify_starting, | |
948 | .teardown = notify_dying, | |
949 | .skip_onerr = true, | |
950 | }, | |
951 | #endif | |
952 | [CPUHP_ONLINE] = { | |
953 | .name = "online", | |
954 | .startup = NULL, | |
955 | .teardown = NULL, | |
956 | }, | |
957 | }; | |
958 | ||
98f8cdce TG |
959 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
960 | { | |
961 | return (state > CPUHP_AP_OFFLINE && state < CPUHP_AP_ONLINE); | |
962 | } | |
963 | ||
964 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) | |
965 | { | |
966 | struct cpuhp_step *sp; | |
967 | ||
968 | sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states; | |
969 | return sp + state; | |
970 | } | |
971 | ||
972 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) | |
973 | static ssize_t show_cpuhp_state(struct device *dev, | |
974 | struct device_attribute *attr, char *buf) | |
975 | { | |
976 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
977 | ||
978 | return sprintf(buf, "%d\n", st->state); | |
979 | } | |
980 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
981 | ||
982 | static ssize_t show_cpuhp_target(struct device *dev, | |
983 | struct device_attribute *attr, char *buf) | |
984 | { | |
985 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
986 | ||
987 | return sprintf(buf, "%d\n", st->target); | |
988 | } | |
989 | static DEVICE_ATTR(target, 0444, show_cpuhp_target, NULL); | |
990 | ||
991 | static struct attribute *cpuhp_cpu_attrs[] = { | |
992 | &dev_attr_state.attr, | |
993 | &dev_attr_target.attr, | |
994 | NULL | |
995 | }; | |
996 | ||
997 | static struct attribute_group cpuhp_cpu_attr_group = { | |
998 | .attrs = cpuhp_cpu_attrs, | |
999 | .name = "hotplug", | |
1000 | NULL | |
1001 | }; | |
1002 | ||
1003 | static ssize_t show_cpuhp_states(struct device *dev, | |
1004 | struct device_attribute *attr, char *buf) | |
1005 | { | |
1006 | ssize_t cur, res = 0; | |
1007 | int i; | |
1008 | ||
1009 | mutex_lock(&cpuhp_state_mutex); | |
1010 | for (i = 0; i <= CPUHP_ONLINE; i++) { | |
1011 | struct cpuhp_step *sp = cpuhp_get_step(i); | |
1012 | ||
1013 | if (sp->name) { | |
1014 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
1015 | buf += cur; | |
1016 | res += cur; | |
1017 | } | |
1018 | } | |
1019 | mutex_unlock(&cpuhp_state_mutex); | |
1020 | return res; | |
1021 | } | |
1022 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
1023 | ||
1024 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
1025 | &dev_attr_states.attr, | |
1026 | NULL | |
1027 | }; | |
1028 | ||
1029 | static struct attribute_group cpuhp_cpu_root_attr_group = { | |
1030 | .attrs = cpuhp_cpu_root_attrs, | |
1031 | .name = "hotplug", | |
1032 | NULL | |
1033 | }; | |
1034 | ||
1035 | static int __init cpuhp_sysfs_init(void) | |
1036 | { | |
1037 | int cpu, ret; | |
1038 | ||
1039 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, | |
1040 | &cpuhp_cpu_root_attr_group); | |
1041 | if (ret) | |
1042 | return ret; | |
1043 | ||
1044 | for_each_possible_cpu(cpu) { | |
1045 | struct device *dev = get_cpu_device(cpu); | |
1046 | ||
1047 | if (!dev) | |
1048 | continue; | |
1049 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
1050 | if (ret) | |
1051 | return ret; | |
1052 | } | |
1053 | return 0; | |
1054 | } | |
1055 | device_initcall(cpuhp_sysfs_init); | |
1056 | #endif | |
1057 | ||
e56b3bc7 LT |
1058 | /* |
1059 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
1060 | * represents all NR_CPUS bits binary values of 1<<nr. | |
1061 | * | |
e0b582ec | 1062 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
1063 | * mask value that has a single bit set only. |
1064 | */ | |
b8d317d1 | 1065 | |
e56b3bc7 | 1066 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 1067 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
1068 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
1069 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
1070 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 1071 | |
e56b3bc7 LT |
1072 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
1073 | ||
1074 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
1075 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
1076 | #if BITS_PER_LONG > 32 | |
1077 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
1078 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
1079 | #endif |
1080 | }; | |
e56b3bc7 | 1081 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
1082 | |
1083 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
1084 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
1085 | |
1086 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 1087 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 1088 | = {CPU_BITS_ALL}; |
b3199c02 | 1089 | #else |
4b804c85 | 1090 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 1091 | #endif |
4b804c85 | 1092 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 1093 | |
4b804c85 RV |
1094 | struct cpumask __cpu_online_mask __read_mostly; |
1095 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 1096 | |
4b804c85 RV |
1097 | struct cpumask __cpu_present_mask __read_mostly; |
1098 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 1099 | |
4b804c85 RV |
1100 | struct cpumask __cpu_active_mask __read_mostly; |
1101 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 1102 | |
3fa41520 RR |
1103 | void init_cpu_present(const struct cpumask *src) |
1104 | { | |
c4c54dd1 | 1105 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
1106 | } |
1107 | ||
1108 | void init_cpu_possible(const struct cpumask *src) | |
1109 | { | |
c4c54dd1 | 1110 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
1111 | } |
1112 | ||
1113 | void init_cpu_online(const struct cpumask *src) | |
1114 | { | |
c4c54dd1 | 1115 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 1116 | } |
cff7d378 TG |
1117 | |
1118 | /* | |
1119 | * Activate the first processor. | |
1120 | */ | |
1121 | void __init boot_cpu_init(void) | |
1122 | { | |
1123 | int cpu = smp_processor_id(); | |
1124 | ||
1125 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
1126 | set_cpu_online(cpu, true); | |
1127 | set_cpu_active(cpu, true); | |
1128 | set_cpu_present(cpu, true); | |
1129 | set_cpu_possible(cpu, true); | |
1130 | } | |
1131 | ||
1132 | /* | |
1133 | * Must be called _AFTER_ setting up the per_cpu areas | |
1134 | */ | |
1135 | void __init boot_cpu_state_init(void) | |
1136 | { | |
1137 | per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE; | |
1138 | } |