| 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> |
| 13 | #include <linux/oom.h> |
| 14 | #include <linux/rcupdate.h> |
| 15 | #include <linux/export.h> |
| 16 | #include <linux/bug.h> |
| 17 | #include <linux/kthread.h> |
| 18 | #include <linux/stop_machine.h> |
| 19 | #include <linux/mutex.h> |
| 20 | #include <linux/gfp.h> |
| 21 | #include <linux/suspend.h> |
| 22 | |
| 23 | #include "smpboot.h" |
| 24 | |
| 25 | #ifdef CONFIG_SMP |
| 26 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
| 27 | static DEFINE_MUTEX(cpu_add_remove_lock); |
| 28 | |
| 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 | |
| 43 | static RAW_NOTIFIER_HEAD(cpu_chain); |
| 44 | |
| 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 | |
| 50 | #ifdef CONFIG_HOTPLUG_CPU |
| 51 | |
| 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; |
| 60 | } cpu_hotplug = { |
| 61 | .active_writer = NULL, |
| 62 | .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock), |
| 63 | .refcount = 0, |
| 64 | }; |
| 65 | |
| 66 | void get_online_cpus(void) |
| 67 | { |
| 68 | might_sleep(); |
| 69 | if (cpu_hotplug.active_writer == current) |
| 70 | return; |
| 71 | mutex_lock(&cpu_hotplug.lock); |
| 72 | cpu_hotplug.refcount++; |
| 73 | mutex_unlock(&cpu_hotplug.lock); |
| 74 | |
| 75 | } |
| 76 | EXPORT_SYMBOL_GPL(get_online_cpus); |
| 77 | |
| 78 | void put_online_cpus(void) |
| 79 | { |
| 80 | if (cpu_hotplug.active_writer == current) |
| 81 | return; |
| 82 | mutex_lock(&cpu_hotplug.lock); |
| 83 | |
| 84 | if (WARN_ON(!cpu_hotplug.refcount)) |
| 85 | cpu_hotplug.refcount++; /* try to fix things up */ |
| 86 | |
| 87 | if (!--cpu_hotplug.refcount && unlikely(cpu_hotplug.active_writer)) |
| 88 | wake_up_process(cpu_hotplug.active_writer); |
| 89 | mutex_unlock(&cpu_hotplug.lock); |
| 90 | |
| 91 | } |
| 92 | EXPORT_SYMBOL_GPL(put_online_cpus); |
| 93 | |
| 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 | * |
| 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. |
| 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 |
| 113 | * get_online_cpus() not an api which is called all that often. |
| 114 | * |
| 115 | */ |
| 116 | static void cpu_hotplug_begin(void) |
| 117 | { |
| 118 | cpu_hotplug.active_writer = current; |
| 119 | |
| 120 | for (;;) { |
| 121 | mutex_lock(&cpu_hotplug.lock); |
| 122 | if (likely(!cpu_hotplug.refcount)) |
| 123 | break; |
| 124 | __set_current_state(TASK_UNINTERRUPTIBLE); |
| 125 | mutex_unlock(&cpu_hotplug.lock); |
| 126 | schedule(); |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | static void cpu_hotplug_done(void) |
| 131 | { |
| 132 | cpu_hotplug.active_writer = NULL; |
| 133 | mutex_unlock(&cpu_hotplug.lock); |
| 134 | } |
| 135 | |
| 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 | |
| 157 | #else /* #if CONFIG_HOTPLUG_CPU */ |
| 158 | static void cpu_hotplug_begin(void) {} |
| 159 | static void cpu_hotplug_done(void) {} |
| 160 | #endif /* #else #if CONFIG_HOTPLUG_CPU */ |
| 161 | |
| 162 | /* Need to know about CPUs going up/down? */ |
| 163 | int __ref register_cpu_notifier(struct notifier_block *nb) |
| 164 | { |
| 165 | int ret; |
| 166 | cpu_maps_update_begin(); |
| 167 | ret = raw_notifier_chain_register(&cpu_chain, nb); |
| 168 | cpu_maps_update_done(); |
| 169 | return ret; |
| 170 | } |
| 171 | |
| 172 | static int __cpu_notify(unsigned long val, void *v, int nr_to_call, |
| 173 | int *nr_calls) |
| 174 | { |
| 175 | int ret; |
| 176 | |
| 177 | ret = __raw_notifier_call_chain(&cpu_chain, val, v, nr_to_call, |
| 178 | nr_calls); |
| 179 | |
| 180 | return notifier_to_errno(ret); |
| 181 | } |
| 182 | |
| 183 | static int cpu_notify(unsigned long val, void *v) |
| 184 | { |
| 185 | return __cpu_notify(val, v, -1, NULL); |
| 186 | } |
| 187 | |
| 188 | #ifdef CONFIG_HOTPLUG_CPU |
| 189 | |
| 190 | static void cpu_notify_nofail(unsigned long val, void *v) |
| 191 | { |
| 192 | BUG_ON(cpu_notify(val, v)); |
| 193 | } |
| 194 | EXPORT_SYMBOL(register_cpu_notifier); |
| 195 | |
| 196 | void __ref unregister_cpu_notifier(struct notifier_block *nb) |
| 197 | { |
| 198 | cpu_maps_update_begin(); |
| 199 | raw_notifier_chain_unregister(&cpu_chain, nb); |
| 200 | cpu_maps_update_done(); |
| 201 | } |
| 202 | EXPORT_SYMBOL(unregister_cpu_notifier); |
| 203 | |
| 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 | */ |
| 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 | */ |
| 227 | WARN_ON(cpu_online(cpu)); |
| 228 | rcu_read_lock(); |
| 229 | for_each_process(p) { |
| 230 | struct task_struct *t; |
| 231 | |
| 232 | /* |
| 233 | * Main thread might exit, but other threads may still have |
| 234 | * a valid mm. Find one. |
| 235 | */ |
| 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 | |
| 245 | static inline void check_for_tasks(int cpu) |
| 246 | { |
| 247 | struct task_struct *p; |
| 248 | cputime_t utime, stime; |
| 249 | |
| 250 | write_lock_irq(&tasklist_lock); |
| 251 | for_each_process(p) { |
| 252 | task_cputime(p, &utime, &stime); |
| 253 | if (task_cpu(p) == cpu && p->state == TASK_RUNNING && |
| 254 | (utime || stime)) |
| 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); |
| 259 | } |
| 260 | write_unlock_irq(&tasklist_lock); |
| 261 | } |
| 262 | |
| 263 | struct take_cpu_down_param { |
| 264 | unsigned long mod; |
| 265 | void *hcpu; |
| 266 | }; |
| 267 | |
| 268 | /* Take this CPU down. */ |
| 269 | static int __ref take_cpu_down(void *_param) |
| 270 | { |
| 271 | struct take_cpu_down_param *param = _param; |
| 272 | int err; |
| 273 | |
| 274 | /* Ensure this CPU doesn't handle any more interrupts. */ |
| 275 | err = __cpu_disable(); |
| 276 | if (err < 0) |
| 277 | return err; |
| 278 | |
| 279 | cpu_notify(CPU_DYING | param->mod, param->hcpu); |
| 280 | /* Park the stopper thread */ |
| 281 | kthread_park(current); |
| 282 | return 0; |
| 283 | } |
| 284 | |
| 285 | /* Requires cpu_add_remove_lock to be held */ |
| 286 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) |
| 287 | { |
| 288 | int err, nr_calls = 0; |
| 289 | void *hcpu = (void *)(long)cpu; |
| 290 | unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; |
| 291 | struct take_cpu_down_param tcd_param = { |
| 292 | .mod = mod, |
| 293 | .hcpu = hcpu, |
| 294 | }; |
| 295 | |
| 296 | if (num_online_cpus() == 1) |
| 297 | return -EBUSY; |
| 298 | |
| 299 | if (!cpu_online(cpu)) |
| 300 | return -EINVAL; |
| 301 | |
| 302 | cpu_hotplug_begin(); |
| 303 | |
| 304 | err = __cpu_notify(CPU_DOWN_PREPARE | mod, hcpu, -1, &nr_calls); |
| 305 | if (err) { |
| 306 | nr_calls--; |
| 307 | __cpu_notify(CPU_DOWN_FAILED | mod, hcpu, nr_calls, NULL); |
| 308 | printk("%s: attempt to take down CPU %u failed\n", |
| 309 | __func__, cpu); |
| 310 | goto out_release; |
| 311 | } |
| 312 | smpboot_park_threads(cpu); |
| 313 | |
| 314 | err = __stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu)); |
| 315 | if (err) { |
| 316 | /* CPU didn't die: tell everyone. Can't complain. */ |
| 317 | smpboot_unpark_threads(cpu); |
| 318 | cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu); |
| 319 | goto out_release; |
| 320 | } |
| 321 | BUG_ON(cpu_online(cpu)); |
| 322 | |
| 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. |
| 327 | * |
| 328 | * Wait for the stop thread to go away. |
| 329 | */ |
| 330 | while (!idle_cpu(cpu)) |
| 331 | cpu_relax(); |
| 332 | |
| 333 | /* This actually kills the CPU. */ |
| 334 | __cpu_die(cpu); |
| 335 | |
| 336 | /* CPU is completely dead: tell everyone. Too late to complain. */ |
| 337 | cpu_notify_nofail(CPU_DEAD | mod, hcpu); |
| 338 | |
| 339 | check_for_tasks(cpu); |
| 340 | |
| 341 | out_release: |
| 342 | cpu_hotplug_done(); |
| 343 | if (!err) |
| 344 | cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu); |
| 345 | return err; |
| 346 | } |
| 347 | |
| 348 | int __ref cpu_down(unsigned int cpu) |
| 349 | { |
| 350 | int err; |
| 351 | |
| 352 | cpu_maps_update_begin(); |
| 353 | |
| 354 | if (cpu_hotplug_disabled) { |
| 355 | err = -EBUSY; |
| 356 | goto out; |
| 357 | } |
| 358 | |
| 359 | err = _cpu_down(cpu, 0); |
| 360 | |
| 361 | out: |
| 362 | cpu_maps_update_done(); |
| 363 | return err; |
| 364 | } |
| 365 | EXPORT_SYMBOL(cpu_down); |
| 366 | #endif /*CONFIG_HOTPLUG_CPU*/ |
| 367 | |
| 368 | /* Requires cpu_add_remove_lock to be held */ |
| 369 | static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen) |
| 370 | { |
| 371 | int ret, nr_calls = 0; |
| 372 | void *hcpu = (void *)(long)cpu; |
| 373 | unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0; |
| 374 | struct task_struct *idle; |
| 375 | |
| 376 | cpu_hotplug_begin(); |
| 377 | |
| 378 | if (cpu_online(cpu) || !cpu_present(cpu)) { |
| 379 | ret = -EINVAL; |
| 380 | goto out; |
| 381 | } |
| 382 | |
| 383 | idle = idle_thread_get(cpu); |
| 384 | if (IS_ERR(idle)) { |
| 385 | ret = PTR_ERR(idle); |
| 386 | goto out; |
| 387 | } |
| 388 | |
| 389 | ret = smpboot_create_threads(cpu); |
| 390 | if (ret) |
| 391 | goto out; |
| 392 | |
| 393 | ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls); |
| 394 | if (ret) { |
| 395 | nr_calls--; |
| 396 | printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n", |
| 397 | __func__, cpu); |
| 398 | goto out_notify; |
| 399 | } |
| 400 | |
| 401 | /* Arch-specific enabling code. */ |
| 402 | ret = __cpu_up(cpu, idle); |
| 403 | if (ret != 0) |
| 404 | goto out_notify; |
| 405 | BUG_ON(!cpu_online(cpu)); |
| 406 | |
| 407 | /* Wake the per cpu threads */ |
| 408 | smpboot_unpark_threads(cpu); |
| 409 | |
| 410 | /* Now call notifier in preparation. */ |
| 411 | cpu_notify(CPU_ONLINE | mod, hcpu); |
| 412 | |
| 413 | out_notify: |
| 414 | if (ret != 0) |
| 415 | __cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL); |
| 416 | out: |
| 417 | cpu_hotplug_done(); |
| 418 | |
| 419 | return ret; |
| 420 | } |
| 421 | |
| 422 | int __cpuinit cpu_up(unsigned int cpu) |
| 423 | { |
| 424 | int err = 0; |
| 425 | |
| 426 | #ifdef CONFIG_MEMORY_HOTPLUG |
| 427 | int nid; |
| 428 | pg_data_t *pgdat; |
| 429 | #endif |
| 430 | |
| 431 | if (!cpu_possible(cpu)) { |
| 432 | printk(KERN_ERR "can't online cpu %d because it is not " |
| 433 | "configured as may-hotadd at boot time\n", cpu); |
| 434 | #if defined(CONFIG_IA64) |
| 435 | printk(KERN_ERR "please check additional_cpus= boot " |
| 436 | "parameter\n"); |
| 437 | #endif |
| 438 | return -EINVAL; |
| 439 | } |
| 440 | |
| 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 | |
| 456 | if (pgdat->node_zonelists->_zonerefs->zone == NULL) { |
| 457 | mutex_lock(&zonelists_mutex); |
| 458 | build_all_zonelists(NULL, NULL); |
| 459 | mutex_unlock(&zonelists_mutex); |
| 460 | } |
| 461 | #endif |
| 462 | |
| 463 | cpu_maps_update_begin(); |
| 464 | |
| 465 | if (cpu_hotplug_disabled) { |
| 466 | err = -EBUSY; |
| 467 | goto out; |
| 468 | } |
| 469 | |
| 470 | err = _cpu_up(cpu, 0); |
| 471 | |
| 472 | out: |
| 473 | cpu_maps_update_done(); |
| 474 | return err; |
| 475 | } |
| 476 | EXPORT_SYMBOL_GPL(cpu_up); |
| 477 | |
| 478 | #ifdef CONFIG_PM_SLEEP_SMP |
| 479 | static cpumask_var_t frozen_cpus; |
| 480 | |
| 481 | int disable_nonboot_cpus(void) |
| 482 | { |
| 483 | int cpu, first_cpu, error = 0; |
| 484 | |
| 485 | cpu_maps_update_begin(); |
| 486 | first_cpu = cpumask_first(cpu_online_mask); |
| 487 | /* |
| 488 | * We take down all of the non-boot CPUs in one shot to avoid races |
| 489 | * with the userspace trying to use the CPU hotplug at the same time |
| 490 | */ |
| 491 | cpumask_clear(frozen_cpus); |
| 492 | |
| 493 | printk("Disabling non-boot CPUs ...\n"); |
| 494 | for_each_online_cpu(cpu) { |
| 495 | if (cpu == first_cpu) |
| 496 | continue; |
| 497 | error = _cpu_down(cpu, 1); |
| 498 | if (!error) |
| 499 | cpumask_set_cpu(cpu, frozen_cpus); |
| 500 | else { |
| 501 | printk(KERN_ERR "Error taking CPU%d down: %d\n", |
| 502 | cpu, error); |
| 503 | break; |
| 504 | } |
| 505 | } |
| 506 | |
| 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 { |
| 512 | printk(KERN_ERR "Non-boot CPUs are not disabled\n"); |
| 513 | } |
| 514 | cpu_maps_update_done(); |
| 515 | return error; |
| 516 | } |
| 517 | |
| 518 | void __weak arch_enable_nonboot_cpus_begin(void) |
| 519 | { |
| 520 | } |
| 521 | |
| 522 | void __weak arch_enable_nonboot_cpus_end(void) |
| 523 | { |
| 524 | } |
| 525 | |
| 526 | void __ref enable_nonboot_cpus(void) |
| 527 | { |
| 528 | int cpu, error; |
| 529 | |
| 530 | /* Allow everyone to use the CPU hotplug again */ |
| 531 | cpu_maps_update_begin(); |
| 532 | cpu_hotplug_disabled = 0; |
| 533 | if (cpumask_empty(frozen_cpus)) |
| 534 | goto out; |
| 535 | |
| 536 | printk(KERN_INFO "Enabling non-boot CPUs ...\n"); |
| 537 | |
| 538 | arch_enable_nonboot_cpus_begin(); |
| 539 | |
| 540 | for_each_cpu(cpu, frozen_cpus) { |
| 541 | error = _cpu_up(cpu, 1); |
| 542 | if (!error) { |
| 543 | printk(KERN_INFO "CPU%d is up\n", cpu); |
| 544 | continue; |
| 545 | } |
| 546 | printk(KERN_WARNING "Error taking CPU%d up: %d\n", cpu, error); |
| 547 | } |
| 548 | |
| 549 | arch_enable_nonboot_cpus_end(); |
| 550 | |
| 551 | cpumask_clear(frozen_cpus); |
| 552 | out: |
| 553 | cpu_maps_update_done(); |
| 554 | } |
| 555 | |
| 556 | static int __init alloc_frozen_cpus(void) |
| 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); |
| 563 | |
| 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: |
| 583 | cpu_hotplug_disable(); |
| 584 | break; |
| 585 | |
| 586 | case PM_POST_SUSPEND: |
| 587 | case PM_POST_HIBERNATION: |
| 588 | cpu_hotplug_enable(); |
| 589 | break; |
| 590 | |
| 591 | default: |
| 592 | return NOTIFY_DONE; |
| 593 | } |
| 594 | |
| 595 | return NOTIFY_OK; |
| 596 | } |
| 597 | |
| 598 | |
| 599 | static int __init cpu_hotplug_pm_sync_init(void) |
| 600 | { |
| 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 | */ |
| 606 | pm_notifier(cpu_hotplug_pm_callback, 0); |
| 607 | return 0; |
| 608 | } |
| 609 | core_initcall(cpu_hotplug_pm_sync_init); |
| 610 | |
| 611 | #endif /* CONFIG_PM_SLEEP_SMP */ |
| 612 | |
| 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 | */ |
| 621 | void __cpuinit notify_cpu_starting(unsigned int cpu) |
| 622 | { |
| 623 | unsigned long val = CPU_STARTING; |
| 624 | |
| 625 | #ifdef CONFIG_PM_SLEEP_SMP |
| 626 | if (frozen_cpus != NULL && cpumask_test_cpu(cpu, frozen_cpus)) |
| 627 | val = CPU_STARTING_FROZEN; |
| 628 | #endif /* CONFIG_PM_SLEEP_SMP */ |
| 629 | cpu_notify(val, (void *)(long)cpu); |
| 630 | } |
| 631 | |
| 632 | #endif /* CONFIG_SMP */ |
| 633 | |
| 634 | /* |
| 635 | * cpu_bit_bitmap[] is a special, "compressed" data structure that |
| 636 | * represents all NR_CPUS bits binary values of 1<<nr. |
| 637 | * |
| 638 | * It is used by cpumask_of() to get a constant address to a CPU |
| 639 | * mask value that has a single bit set only. |
| 640 | */ |
| 641 | |
| 642 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
| 643 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
| 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) |
| 647 | |
| 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), |
| 655 | #endif |
| 656 | }; |
| 657 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
| 658 | |
| 659 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; |
| 660 | EXPORT_SYMBOL(cpu_all_bits); |
| 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); |
| 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 | } |