| 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/signal.h> |
| 11 | #include <linux/sched/hotplug.h> |
| 12 | #include <linux/sched/task.h> |
| 13 | #include <linux/unistd.h> |
| 14 | #include <linux/cpu.h> |
| 15 | #include <linux/oom.h> |
| 16 | #include <linux/rcupdate.h> |
| 17 | #include <linux/export.h> |
| 18 | #include <linux/bug.h> |
| 19 | #include <linux/kthread.h> |
| 20 | #include <linux/stop_machine.h> |
| 21 | #include <linux/mutex.h> |
| 22 | #include <linux/gfp.h> |
| 23 | #include <linux/suspend.h> |
| 24 | #include <linux/lockdep.h> |
| 25 | #include <linux/tick.h> |
| 26 | #include <linux/irq.h> |
| 27 | #include <linux/smpboot.h> |
| 28 | #include <linux/relay.h> |
| 29 | #include <linux/slab.h> |
| 30 | #include <linux/percpu-rwsem.h> |
| 31 | |
| 32 | #include <trace/events/power.h> |
| 33 | #define CREATE_TRACE_POINTS |
| 34 | #include <trace/events/cpuhp.h> |
| 35 | |
| 36 | #include "smpboot.h" |
| 37 | |
| 38 | /** |
| 39 | * cpuhp_cpu_state - Per cpu hotplug state storage |
| 40 | * @state: The current cpu state |
| 41 | * @target: The target state |
| 42 | * @thread: Pointer to the hotplug thread |
| 43 | * @should_run: Thread should execute |
| 44 | * @rollback: Perform a rollback |
| 45 | * @single: Single callback invocation |
| 46 | * @bringup: Single callback bringup or teardown selector |
| 47 | * @cb_state: The state for a single callback (install/uninstall) |
| 48 | * @result: Result of the operation |
| 49 | * @done: Signal completion to the issuer of the task |
| 50 | */ |
| 51 | struct cpuhp_cpu_state { |
| 52 | enum cpuhp_state state; |
| 53 | enum cpuhp_state target; |
| 54 | #ifdef CONFIG_SMP |
| 55 | struct task_struct *thread; |
| 56 | bool should_run; |
| 57 | bool rollback; |
| 58 | bool single; |
| 59 | bool bringup; |
| 60 | struct hlist_node *node; |
| 61 | enum cpuhp_state cb_state; |
| 62 | int result; |
| 63 | struct completion done; |
| 64 | #endif |
| 65 | }; |
| 66 | |
| 67 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state); |
| 68 | |
| 69 | #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) |
| 70 | static struct lock_class_key cpuhp_state_key; |
| 71 | static struct lockdep_map cpuhp_state_lock_map = |
| 72 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state", &cpuhp_state_key); |
| 73 | #endif |
| 74 | |
| 75 | /** |
| 76 | * cpuhp_step - Hotplug state machine step |
| 77 | * @name: Name of the step |
| 78 | * @startup: Startup function of the step |
| 79 | * @teardown: Teardown function of the step |
| 80 | * @skip_onerr: Do not invoke the functions on error rollback |
| 81 | * Will go away once the notifiers are gone |
| 82 | * @cant_stop: Bringup/teardown can't be stopped at this step |
| 83 | */ |
| 84 | struct cpuhp_step { |
| 85 | const char *name; |
| 86 | union { |
| 87 | int (*single)(unsigned int cpu); |
| 88 | int (*multi)(unsigned int cpu, |
| 89 | struct hlist_node *node); |
| 90 | } startup; |
| 91 | union { |
| 92 | int (*single)(unsigned int cpu); |
| 93 | int (*multi)(unsigned int cpu, |
| 94 | struct hlist_node *node); |
| 95 | } teardown; |
| 96 | struct hlist_head list; |
| 97 | bool skip_onerr; |
| 98 | bool cant_stop; |
| 99 | bool multi_instance; |
| 100 | }; |
| 101 | |
| 102 | static DEFINE_MUTEX(cpuhp_state_mutex); |
| 103 | static struct cpuhp_step cpuhp_bp_states[]; |
| 104 | static struct cpuhp_step cpuhp_ap_states[]; |
| 105 | |
| 106 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
| 107 | { |
| 108 | /* |
| 109 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation |
| 110 | * purposes as that state is handled explicitly in cpu_down. |
| 111 | */ |
| 112 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; |
| 113 | } |
| 114 | |
| 115 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) |
| 116 | { |
| 117 | struct cpuhp_step *sp; |
| 118 | |
| 119 | sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states; |
| 120 | return sp + state; |
| 121 | } |
| 122 | |
| 123 | /** |
| 124 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state |
| 125 | * @cpu: The cpu for which the callback should be invoked |
| 126 | * @step: The step in the state machine |
| 127 | * @bringup: True if the bringup callback should be invoked |
| 128 | * |
| 129 | * Called from cpu hotplug and from the state register machinery. |
| 130 | */ |
| 131 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
| 132 | bool bringup, struct hlist_node *node) |
| 133 | { |
| 134 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 135 | struct cpuhp_step *step = cpuhp_get_step(state); |
| 136 | int (*cbm)(unsigned int cpu, struct hlist_node *node); |
| 137 | int (*cb)(unsigned int cpu); |
| 138 | int ret, cnt; |
| 139 | |
| 140 | if (!step->multi_instance) { |
| 141 | cb = bringup ? step->startup.single : step->teardown.single; |
| 142 | if (!cb) |
| 143 | return 0; |
| 144 | trace_cpuhp_enter(cpu, st->target, state, cb); |
| 145 | ret = cb(cpu); |
| 146 | trace_cpuhp_exit(cpu, st->state, state, ret); |
| 147 | return ret; |
| 148 | } |
| 149 | cbm = bringup ? step->startup.multi : step->teardown.multi; |
| 150 | if (!cbm) |
| 151 | return 0; |
| 152 | |
| 153 | /* Single invocation for instance add/remove */ |
| 154 | if (node) { |
| 155 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
| 156 | ret = cbm(cpu, node); |
| 157 | trace_cpuhp_exit(cpu, st->state, state, ret); |
| 158 | return ret; |
| 159 | } |
| 160 | |
| 161 | /* State transition. Invoke on all instances */ |
| 162 | cnt = 0; |
| 163 | hlist_for_each(node, &step->list) { |
| 164 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
| 165 | ret = cbm(cpu, node); |
| 166 | trace_cpuhp_exit(cpu, st->state, state, ret); |
| 167 | if (ret) |
| 168 | goto err; |
| 169 | cnt++; |
| 170 | } |
| 171 | return 0; |
| 172 | err: |
| 173 | /* Rollback the instances if one failed */ |
| 174 | cbm = !bringup ? step->startup.multi : step->teardown.multi; |
| 175 | if (!cbm) |
| 176 | return ret; |
| 177 | |
| 178 | hlist_for_each(node, &step->list) { |
| 179 | if (!cnt--) |
| 180 | break; |
| 181 | cbm(cpu, node); |
| 182 | } |
| 183 | return ret; |
| 184 | } |
| 185 | |
| 186 | #ifdef CONFIG_SMP |
| 187 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
| 188 | static DEFINE_MUTEX(cpu_add_remove_lock); |
| 189 | bool cpuhp_tasks_frozen; |
| 190 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); |
| 191 | |
| 192 | /* |
| 193 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
| 194 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. |
| 195 | */ |
| 196 | void cpu_maps_update_begin(void) |
| 197 | { |
| 198 | mutex_lock(&cpu_add_remove_lock); |
| 199 | } |
| 200 | |
| 201 | void cpu_maps_update_done(void) |
| 202 | { |
| 203 | mutex_unlock(&cpu_add_remove_lock); |
| 204 | } |
| 205 | |
| 206 | /* |
| 207 | * If set, cpu_up and cpu_down will return -EBUSY and do nothing. |
| 208 | * Should always be manipulated under cpu_add_remove_lock |
| 209 | */ |
| 210 | static int cpu_hotplug_disabled; |
| 211 | |
| 212 | #ifdef CONFIG_HOTPLUG_CPU |
| 213 | |
| 214 | DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); |
| 215 | |
| 216 | void cpus_read_lock(void) |
| 217 | { |
| 218 | percpu_down_read(&cpu_hotplug_lock); |
| 219 | } |
| 220 | EXPORT_SYMBOL_GPL(cpus_read_lock); |
| 221 | |
| 222 | void cpus_read_unlock(void) |
| 223 | { |
| 224 | percpu_up_read(&cpu_hotplug_lock); |
| 225 | } |
| 226 | EXPORT_SYMBOL_GPL(cpus_read_unlock); |
| 227 | |
| 228 | void cpus_write_lock(void) |
| 229 | { |
| 230 | percpu_down_write(&cpu_hotplug_lock); |
| 231 | } |
| 232 | |
| 233 | void cpus_write_unlock(void) |
| 234 | { |
| 235 | percpu_up_write(&cpu_hotplug_lock); |
| 236 | } |
| 237 | |
| 238 | void lockdep_assert_cpus_held(void) |
| 239 | { |
| 240 | percpu_rwsem_assert_held(&cpu_hotplug_lock); |
| 241 | } |
| 242 | |
| 243 | /* |
| 244 | * Wait for currently running CPU hotplug operations to complete (if any) and |
| 245 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects |
| 246 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the |
| 247 | * hotplug path before performing hotplug operations. So acquiring that lock |
| 248 | * guarantees mutual exclusion from any currently running hotplug operations. |
| 249 | */ |
| 250 | void cpu_hotplug_disable(void) |
| 251 | { |
| 252 | cpu_maps_update_begin(); |
| 253 | cpu_hotplug_disabled++; |
| 254 | cpu_maps_update_done(); |
| 255 | } |
| 256 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
| 257 | |
| 258 | static void __cpu_hotplug_enable(void) |
| 259 | { |
| 260 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) |
| 261 | return; |
| 262 | cpu_hotplug_disabled--; |
| 263 | } |
| 264 | |
| 265 | void cpu_hotplug_enable(void) |
| 266 | { |
| 267 | cpu_maps_update_begin(); |
| 268 | __cpu_hotplug_enable(); |
| 269 | cpu_maps_update_done(); |
| 270 | } |
| 271 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
| 272 | #endif /* CONFIG_HOTPLUG_CPU */ |
| 273 | |
| 274 | static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st); |
| 275 | |
| 276 | static int bringup_wait_for_ap(unsigned int cpu) |
| 277 | { |
| 278 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 279 | |
| 280 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
| 281 | wait_for_completion(&st->done); |
| 282 | if (WARN_ON_ONCE((!cpu_online(cpu)))) |
| 283 | return -ECANCELED; |
| 284 | |
| 285 | /* Unpark the stopper thread and the hotplug thread of the target cpu */ |
| 286 | stop_machine_unpark(cpu); |
| 287 | kthread_unpark(st->thread); |
| 288 | |
| 289 | /* Should we go further up ? */ |
| 290 | if (st->target > CPUHP_AP_ONLINE_IDLE) { |
| 291 | __cpuhp_kick_ap_work(st); |
| 292 | wait_for_completion(&st->done); |
| 293 | } |
| 294 | return st->result; |
| 295 | } |
| 296 | |
| 297 | static int bringup_cpu(unsigned int cpu) |
| 298 | { |
| 299 | struct task_struct *idle = idle_thread_get(cpu); |
| 300 | int ret; |
| 301 | |
| 302 | /* |
| 303 | * Some architectures have to walk the irq descriptors to |
| 304 | * setup the vector space for the cpu which comes online. |
| 305 | * Prevent irq alloc/free across the bringup. |
| 306 | */ |
| 307 | irq_lock_sparse(); |
| 308 | |
| 309 | /* Arch-specific enabling code. */ |
| 310 | ret = __cpu_up(cpu, idle); |
| 311 | irq_unlock_sparse(); |
| 312 | if (ret) |
| 313 | return ret; |
| 314 | return bringup_wait_for_ap(cpu); |
| 315 | } |
| 316 | |
| 317 | /* |
| 318 | * Hotplug state machine related functions |
| 319 | */ |
| 320 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) |
| 321 | { |
| 322 | for (st->state++; st->state < st->target; st->state++) { |
| 323 | struct cpuhp_step *step = cpuhp_get_step(st->state); |
| 324 | |
| 325 | if (!step->skip_onerr) |
| 326 | cpuhp_invoke_callback(cpu, st->state, true, NULL); |
| 327 | } |
| 328 | } |
| 329 | |
| 330 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
| 331 | enum cpuhp_state target) |
| 332 | { |
| 333 | enum cpuhp_state prev_state = st->state; |
| 334 | int ret = 0; |
| 335 | |
| 336 | for (; st->state > target; st->state--) { |
| 337 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL); |
| 338 | if (ret) { |
| 339 | st->target = prev_state; |
| 340 | undo_cpu_down(cpu, st); |
| 341 | break; |
| 342 | } |
| 343 | } |
| 344 | return ret; |
| 345 | } |
| 346 | |
| 347 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) |
| 348 | { |
| 349 | for (st->state--; st->state > st->target; st->state--) { |
| 350 | struct cpuhp_step *step = cpuhp_get_step(st->state); |
| 351 | |
| 352 | if (!step->skip_onerr) |
| 353 | cpuhp_invoke_callback(cpu, st->state, false, NULL); |
| 354 | } |
| 355 | } |
| 356 | |
| 357 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
| 358 | enum cpuhp_state target) |
| 359 | { |
| 360 | enum cpuhp_state prev_state = st->state; |
| 361 | int ret = 0; |
| 362 | |
| 363 | while (st->state < target) { |
| 364 | st->state++; |
| 365 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL); |
| 366 | if (ret) { |
| 367 | st->target = prev_state; |
| 368 | undo_cpu_up(cpu, st); |
| 369 | break; |
| 370 | } |
| 371 | } |
| 372 | return ret; |
| 373 | } |
| 374 | |
| 375 | /* |
| 376 | * The cpu hotplug threads manage the bringup and teardown of the cpus |
| 377 | */ |
| 378 | static void cpuhp_create(unsigned int cpu) |
| 379 | { |
| 380 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 381 | |
| 382 | init_completion(&st->done); |
| 383 | } |
| 384 | |
| 385 | static int cpuhp_should_run(unsigned int cpu) |
| 386 | { |
| 387 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| 388 | |
| 389 | return st->should_run; |
| 390 | } |
| 391 | |
| 392 | /* Execute the teardown callbacks. Used to be CPU_DOWN_PREPARE */ |
| 393 | static int cpuhp_ap_offline(unsigned int cpu, struct cpuhp_cpu_state *st) |
| 394 | { |
| 395 | enum cpuhp_state target = max((int)st->target, CPUHP_TEARDOWN_CPU); |
| 396 | |
| 397 | return cpuhp_down_callbacks(cpu, st, target); |
| 398 | } |
| 399 | |
| 400 | /* Execute the online startup callbacks. Used to be CPU_ONLINE */ |
| 401 | static int cpuhp_ap_online(unsigned int cpu, struct cpuhp_cpu_state *st) |
| 402 | { |
| 403 | return cpuhp_up_callbacks(cpu, st, st->target); |
| 404 | } |
| 405 | |
| 406 | /* |
| 407 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke |
| 408 | * callbacks when a state gets [un]installed at runtime. |
| 409 | */ |
| 410 | static void cpuhp_thread_fun(unsigned int cpu) |
| 411 | { |
| 412 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| 413 | int ret = 0; |
| 414 | |
| 415 | /* |
| 416 | * Paired with the mb() in cpuhp_kick_ap_work and |
| 417 | * cpuhp_invoke_ap_callback, so the work set is consistent visible. |
| 418 | */ |
| 419 | smp_mb(); |
| 420 | if (!st->should_run) |
| 421 | return; |
| 422 | |
| 423 | st->should_run = false; |
| 424 | |
| 425 | lock_map_acquire(&cpuhp_state_lock_map); |
| 426 | /* Single callback invocation for [un]install ? */ |
| 427 | if (st->single) { |
| 428 | if (st->cb_state < CPUHP_AP_ONLINE) { |
| 429 | local_irq_disable(); |
| 430 | ret = cpuhp_invoke_callback(cpu, st->cb_state, |
| 431 | st->bringup, st->node); |
| 432 | local_irq_enable(); |
| 433 | } else { |
| 434 | ret = cpuhp_invoke_callback(cpu, st->cb_state, |
| 435 | st->bringup, st->node); |
| 436 | } |
| 437 | } else if (st->rollback) { |
| 438 | BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE); |
| 439 | |
| 440 | undo_cpu_down(cpu, st); |
| 441 | st->rollback = false; |
| 442 | } else { |
| 443 | /* Cannot happen .... */ |
| 444 | BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE); |
| 445 | |
| 446 | /* Regular hotplug work */ |
| 447 | if (st->state < st->target) |
| 448 | ret = cpuhp_ap_online(cpu, st); |
| 449 | else if (st->state > st->target) |
| 450 | ret = cpuhp_ap_offline(cpu, st); |
| 451 | } |
| 452 | lock_map_release(&cpuhp_state_lock_map); |
| 453 | st->result = ret; |
| 454 | complete(&st->done); |
| 455 | } |
| 456 | |
| 457 | /* Invoke a single callback on a remote cpu */ |
| 458 | static int |
| 459 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
| 460 | struct hlist_node *node) |
| 461 | { |
| 462 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 463 | |
| 464 | if (!cpu_online(cpu)) |
| 465 | return 0; |
| 466 | |
| 467 | lock_map_acquire(&cpuhp_state_lock_map); |
| 468 | lock_map_release(&cpuhp_state_lock_map); |
| 469 | |
| 470 | /* |
| 471 | * If we are up and running, use the hotplug thread. For early calls |
| 472 | * we invoke the thread function directly. |
| 473 | */ |
| 474 | if (!st->thread) |
| 475 | return cpuhp_invoke_callback(cpu, state, bringup, node); |
| 476 | |
| 477 | st->cb_state = state; |
| 478 | st->single = true; |
| 479 | st->bringup = bringup; |
| 480 | st->node = node; |
| 481 | |
| 482 | /* |
| 483 | * Make sure the above stores are visible before should_run becomes |
| 484 | * true. Paired with the mb() above in cpuhp_thread_fun() |
| 485 | */ |
| 486 | smp_mb(); |
| 487 | st->should_run = true; |
| 488 | wake_up_process(st->thread); |
| 489 | wait_for_completion(&st->done); |
| 490 | return st->result; |
| 491 | } |
| 492 | |
| 493 | /* Regular hotplug invocation of the AP hotplug thread */ |
| 494 | static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st) |
| 495 | { |
| 496 | st->result = 0; |
| 497 | st->single = false; |
| 498 | /* |
| 499 | * Make sure the above stores are visible before should_run becomes |
| 500 | * true. Paired with the mb() above in cpuhp_thread_fun() |
| 501 | */ |
| 502 | smp_mb(); |
| 503 | st->should_run = true; |
| 504 | wake_up_process(st->thread); |
| 505 | } |
| 506 | |
| 507 | static int cpuhp_kick_ap_work(unsigned int cpu) |
| 508 | { |
| 509 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 510 | enum cpuhp_state state = st->state; |
| 511 | |
| 512 | trace_cpuhp_enter(cpu, st->target, state, cpuhp_kick_ap_work); |
| 513 | lock_map_acquire(&cpuhp_state_lock_map); |
| 514 | lock_map_release(&cpuhp_state_lock_map); |
| 515 | __cpuhp_kick_ap_work(st); |
| 516 | wait_for_completion(&st->done); |
| 517 | trace_cpuhp_exit(cpu, st->state, state, st->result); |
| 518 | return st->result; |
| 519 | } |
| 520 | |
| 521 | static struct smp_hotplug_thread cpuhp_threads = { |
| 522 | .store = &cpuhp_state.thread, |
| 523 | .create = &cpuhp_create, |
| 524 | .thread_should_run = cpuhp_should_run, |
| 525 | .thread_fn = cpuhp_thread_fun, |
| 526 | .thread_comm = "cpuhp/%u", |
| 527 | .selfparking = true, |
| 528 | }; |
| 529 | |
| 530 | void __init cpuhp_threads_init(void) |
| 531 | { |
| 532 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); |
| 533 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); |
| 534 | } |
| 535 | |
| 536 | #ifdef CONFIG_HOTPLUG_CPU |
| 537 | /** |
| 538 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU |
| 539 | * @cpu: a CPU id |
| 540 | * |
| 541 | * This function walks all processes, finds a valid mm struct for each one and |
| 542 | * then clears a corresponding bit in mm's cpumask. While this all sounds |
| 543 | * trivial, there are various non-obvious corner cases, which this function |
| 544 | * tries to solve in a safe manner. |
| 545 | * |
| 546 | * Also note that the function uses a somewhat relaxed locking scheme, so it may |
| 547 | * be called only for an already offlined CPU. |
| 548 | */ |
| 549 | void clear_tasks_mm_cpumask(int cpu) |
| 550 | { |
| 551 | struct task_struct *p; |
| 552 | |
| 553 | /* |
| 554 | * This function is called after the cpu is taken down and marked |
| 555 | * offline, so its not like new tasks will ever get this cpu set in |
| 556 | * their mm mask. -- Peter Zijlstra |
| 557 | * Thus, we may use rcu_read_lock() here, instead of grabbing |
| 558 | * full-fledged tasklist_lock. |
| 559 | */ |
| 560 | WARN_ON(cpu_online(cpu)); |
| 561 | rcu_read_lock(); |
| 562 | for_each_process(p) { |
| 563 | struct task_struct *t; |
| 564 | |
| 565 | /* |
| 566 | * Main thread might exit, but other threads may still have |
| 567 | * a valid mm. Find one. |
| 568 | */ |
| 569 | t = find_lock_task_mm(p); |
| 570 | if (!t) |
| 571 | continue; |
| 572 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); |
| 573 | task_unlock(t); |
| 574 | } |
| 575 | rcu_read_unlock(); |
| 576 | } |
| 577 | |
| 578 | /* Take this CPU down. */ |
| 579 | static int take_cpu_down(void *_param) |
| 580 | { |
| 581 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| 582 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); |
| 583 | int err, cpu = smp_processor_id(); |
| 584 | |
| 585 | /* Ensure this CPU doesn't handle any more interrupts. */ |
| 586 | err = __cpu_disable(); |
| 587 | if (err < 0) |
| 588 | return err; |
| 589 | |
| 590 | /* |
| 591 | * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not |
| 592 | * do this step again. |
| 593 | */ |
| 594 | WARN_ON(st->state != CPUHP_TEARDOWN_CPU); |
| 595 | st->state--; |
| 596 | /* Invoke the former CPU_DYING callbacks */ |
| 597 | for (; st->state > target; st->state--) |
| 598 | cpuhp_invoke_callback(cpu, st->state, false, NULL); |
| 599 | |
| 600 | /* Give up timekeeping duties */ |
| 601 | tick_handover_do_timer(); |
| 602 | /* Park the stopper thread */ |
| 603 | stop_machine_park(cpu); |
| 604 | return 0; |
| 605 | } |
| 606 | |
| 607 | static int takedown_cpu(unsigned int cpu) |
| 608 | { |
| 609 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 610 | int err; |
| 611 | |
| 612 | /* Park the smpboot threads */ |
| 613 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
| 614 | smpboot_park_threads(cpu); |
| 615 | |
| 616 | /* |
| 617 | * Prevent irq alloc/free while the dying cpu reorganizes the |
| 618 | * interrupt affinities. |
| 619 | */ |
| 620 | irq_lock_sparse(); |
| 621 | |
| 622 | /* |
| 623 | * So now all preempt/rcu users must observe !cpu_active(). |
| 624 | */ |
| 625 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
| 626 | if (err) { |
| 627 | /* CPU refused to die */ |
| 628 | irq_unlock_sparse(); |
| 629 | /* Unpark the hotplug thread so we can rollback there */ |
| 630 | kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
| 631 | return err; |
| 632 | } |
| 633 | BUG_ON(cpu_online(cpu)); |
| 634 | |
| 635 | /* |
| 636 | * The CPUHP_AP_SCHED_MIGRATE_DYING callback will have removed all |
| 637 | * runnable tasks from the cpu, there's only the idle task left now |
| 638 | * that the migration thread is done doing the stop_machine thing. |
| 639 | * |
| 640 | * Wait for the stop thread to go away. |
| 641 | */ |
| 642 | wait_for_completion(&st->done); |
| 643 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
| 644 | |
| 645 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
| 646 | irq_unlock_sparse(); |
| 647 | |
| 648 | hotplug_cpu__broadcast_tick_pull(cpu); |
| 649 | /* This actually kills the CPU. */ |
| 650 | __cpu_die(cpu); |
| 651 | |
| 652 | tick_cleanup_dead_cpu(cpu); |
| 653 | rcutree_migrate_callbacks(cpu); |
| 654 | return 0; |
| 655 | } |
| 656 | |
| 657 | static void cpuhp_complete_idle_dead(void *arg) |
| 658 | { |
| 659 | struct cpuhp_cpu_state *st = arg; |
| 660 | |
| 661 | complete(&st->done); |
| 662 | } |
| 663 | |
| 664 | void cpuhp_report_idle_dead(void) |
| 665 | { |
| 666 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| 667 | |
| 668 | BUG_ON(st->state != CPUHP_AP_OFFLINE); |
| 669 | rcu_report_dead(smp_processor_id()); |
| 670 | st->state = CPUHP_AP_IDLE_DEAD; |
| 671 | /* |
| 672 | * We cannot call complete after rcu_report_dead() so we delegate it |
| 673 | * to an online cpu. |
| 674 | */ |
| 675 | smp_call_function_single(cpumask_first(cpu_online_mask), |
| 676 | cpuhp_complete_idle_dead, st, 0); |
| 677 | } |
| 678 | |
| 679 | #else |
| 680 | #define takedown_cpu NULL |
| 681 | #endif |
| 682 | |
| 683 | #ifdef CONFIG_HOTPLUG_CPU |
| 684 | |
| 685 | /* Requires cpu_add_remove_lock to be held */ |
| 686 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
| 687 | enum cpuhp_state target) |
| 688 | { |
| 689 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 690 | int prev_state, ret = 0; |
| 691 | |
| 692 | if (num_online_cpus() == 1) |
| 693 | return -EBUSY; |
| 694 | |
| 695 | if (!cpu_present(cpu)) |
| 696 | return -EINVAL; |
| 697 | |
| 698 | cpus_write_lock(); |
| 699 | |
| 700 | cpuhp_tasks_frozen = tasks_frozen; |
| 701 | |
| 702 | prev_state = st->state; |
| 703 | st->target = target; |
| 704 | /* |
| 705 | * If the current CPU state is in the range of the AP hotplug thread, |
| 706 | * then we need to kick the thread. |
| 707 | */ |
| 708 | if (st->state > CPUHP_TEARDOWN_CPU) { |
| 709 | ret = cpuhp_kick_ap_work(cpu); |
| 710 | /* |
| 711 | * The AP side has done the error rollback already. Just |
| 712 | * return the error code.. |
| 713 | */ |
| 714 | if (ret) |
| 715 | goto out; |
| 716 | |
| 717 | /* |
| 718 | * We might have stopped still in the range of the AP hotplug |
| 719 | * thread. Nothing to do anymore. |
| 720 | */ |
| 721 | if (st->state > CPUHP_TEARDOWN_CPU) |
| 722 | goto out; |
| 723 | } |
| 724 | /* |
| 725 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
| 726 | * to do the further cleanups. |
| 727 | */ |
| 728 | ret = cpuhp_down_callbacks(cpu, st, target); |
| 729 | if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) { |
| 730 | st->target = prev_state; |
| 731 | st->rollback = true; |
| 732 | cpuhp_kick_ap_work(cpu); |
| 733 | } |
| 734 | |
| 735 | out: |
| 736 | cpus_write_unlock(); |
| 737 | return ret; |
| 738 | } |
| 739 | |
| 740 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) |
| 741 | { |
| 742 | int err; |
| 743 | |
| 744 | cpu_maps_update_begin(); |
| 745 | |
| 746 | if (cpu_hotplug_disabled) { |
| 747 | err = -EBUSY; |
| 748 | goto out; |
| 749 | } |
| 750 | |
| 751 | err = _cpu_down(cpu, 0, target); |
| 752 | |
| 753 | out: |
| 754 | cpu_maps_update_done(); |
| 755 | return err; |
| 756 | } |
| 757 | int cpu_down(unsigned int cpu) |
| 758 | { |
| 759 | return do_cpu_down(cpu, CPUHP_OFFLINE); |
| 760 | } |
| 761 | EXPORT_SYMBOL(cpu_down); |
| 762 | #endif /*CONFIG_HOTPLUG_CPU*/ |
| 763 | |
| 764 | /** |
| 765 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
| 766 | * @cpu: cpu that just started |
| 767 | * |
| 768 | * It must be called by the arch code on the new cpu, before the new cpu |
| 769 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). |
| 770 | */ |
| 771 | void notify_cpu_starting(unsigned int cpu) |
| 772 | { |
| 773 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 774 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); |
| 775 | |
| 776 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
| 777 | while (st->state < target) { |
| 778 | st->state++; |
| 779 | cpuhp_invoke_callback(cpu, st->state, true, NULL); |
| 780 | } |
| 781 | } |
| 782 | |
| 783 | /* |
| 784 | * Called from the idle task. Wake up the controlling task which brings the |
| 785 | * stopper and the hotplug thread of the upcoming CPU up and then delegates |
| 786 | * the rest of the online bringup to the hotplug thread. |
| 787 | */ |
| 788 | void cpuhp_online_idle(enum cpuhp_state state) |
| 789 | { |
| 790 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| 791 | |
| 792 | /* Happens for the boot cpu */ |
| 793 | if (state != CPUHP_AP_ONLINE_IDLE) |
| 794 | return; |
| 795 | |
| 796 | st->state = CPUHP_AP_ONLINE_IDLE; |
| 797 | complete(&st->done); |
| 798 | } |
| 799 | |
| 800 | /* Requires cpu_add_remove_lock to be held */ |
| 801 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
| 802 | { |
| 803 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 804 | struct task_struct *idle; |
| 805 | int ret = 0; |
| 806 | |
| 807 | cpus_write_lock(); |
| 808 | |
| 809 | if (!cpu_present(cpu)) { |
| 810 | ret = -EINVAL; |
| 811 | goto out; |
| 812 | } |
| 813 | |
| 814 | /* |
| 815 | * The caller of do_cpu_up might have raced with another |
| 816 | * caller. Ignore it for now. |
| 817 | */ |
| 818 | if (st->state >= target) |
| 819 | goto out; |
| 820 | |
| 821 | if (st->state == CPUHP_OFFLINE) { |
| 822 | /* Let it fail before we try to bring the cpu up */ |
| 823 | idle = idle_thread_get(cpu); |
| 824 | if (IS_ERR(idle)) { |
| 825 | ret = PTR_ERR(idle); |
| 826 | goto out; |
| 827 | } |
| 828 | } |
| 829 | |
| 830 | cpuhp_tasks_frozen = tasks_frozen; |
| 831 | |
| 832 | st->target = target; |
| 833 | /* |
| 834 | * If the current CPU state is in the range of the AP hotplug thread, |
| 835 | * then we need to kick the thread once more. |
| 836 | */ |
| 837 | if (st->state > CPUHP_BRINGUP_CPU) { |
| 838 | ret = cpuhp_kick_ap_work(cpu); |
| 839 | /* |
| 840 | * The AP side has done the error rollback already. Just |
| 841 | * return the error code.. |
| 842 | */ |
| 843 | if (ret) |
| 844 | goto out; |
| 845 | } |
| 846 | |
| 847 | /* |
| 848 | * Try to reach the target state. We max out on the BP at |
| 849 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
| 850 | * responsible for bringing it up to the target state. |
| 851 | */ |
| 852 | target = min((int)target, CPUHP_BRINGUP_CPU); |
| 853 | ret = cpuhp_up_callbacks(cpu, st, target); |
| 854 | out: |
| 855 | cpus_write_unlock(); |
| 856 | return ret; |
| 857 | } |
| 858 | |
| 859 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) |
| 860 | { |
| 861 | int err = 0; |
| 862 | |
| 863 | if (!cpu_possible(cpu)) { |
| 864 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
| 865 | cpu); |
| 866 | #if defined(CONFIG_IA64) |
| 867 | pr_err("please check additional_cpus= boot parameter\n"); |
| 868 | #endif |
| 869 | return -EINVAL; |
| 870 | } |
| 871 | |
| 872 | err = try_online_node(cpu_to_node(cpu)); |
| 873 | if (err) |
| 874 | return err; |
| 875 | |
| 876 | cpu_maps_update_begin(); |
| 877 | |
| 878 | if (cpu_hotplug_disabled) { |
| 879 | err = -EBUSY; |
| 880 | goto out; |
| 881 | } |
| 882 | |
| 883 | err = _cpu_up(cpu, 0, target); |
| 884 | out: |
| 885 | cpu_maps_update_done(); |
| 886 | return err; |
| 887 | } |
| 888 | |
| 889 | int cpu_up(unsigned int cpu) |
| 890 | { |
| 891 | return do_cpu_up(cpu, CPUHP_ONLINE); |
| 892 | } |
| 893 | EXPORT_SYMBOL_GPL(cpu_up); |
| 894 | |
| 895 | #ifdef CONFIG_PM_SLEEP_SMP |
| 896 | static cpumask_var_t frozen_cpus; |
| 897 | |
| 898 | int freeze_secondary_cpus(int primary) |
| 899 | { |
| 900 | int cpu, error = 0; |
| 901 | |
| 902 | cpu_maps_update_begin(); |
| 903 | if (!cpu_online(primary)) |
| 904 | primary = cpumask_first(cpu_online_mask); |
| 905 | /* |
| 906 | * We take down all of the non-boot CPUs in one shot to avoid races |
| 907 | * with the userspace trying to use the CPU hotplug at the same time |
| 908 | */ |
| 909 | cpumask_clear(frozen_cpus); |
| 910 | |
| 911 | pr_info("Disabling non-boot CPUs ...\n"); |
| 912 | for_each_online_cpu(cpu) { |
| 913 | if (cpu == primary) |
| 914 | continue; |
| 915 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
| 916 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
| 917 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
| 918 | if (!error) |
| 919 | cpumask_set_cpu(cpu, frozen_cpus); |
| 920 | else { |
| 921 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
| 922 | break; |
| 923 | } |
| 924 | } |
| 925 | |
| 926 | if (!error) |
| 927 | BUG_ON(num_online_cpus() > 1); |
| 928 | else |
| 929 | pr_err("Non-boot CPUs are not disabled\n"); |
| 930 | |
| 931 | /* |
| 932 | * Make sure the CPUs won't be enabled by someone else. We need to do |
| 933 | * this even in case of failure as all disable_nonboot_cpus() users are |
| 934 | * supposed to do enable_nonboot_cpus() on the failure path. |
| 935 | */ |
| 936 | cpu_hotplug_disabled++; |
| 937 | |
| 938 | cpu_maps_update_done(); |
| 939 | return error; |
| 940 | } |
| 941 | |
| 942 | void __weak arch_enable_nonboot_cpus_begin(void) |
| 943 | { |
| 944 | } |
| 945 | |
| 946 | void __weak arch_enable_nonboot_cpus_end(void) |
| 947 | { |
| 948 | } |
| 949 | |
| 950 | void enable_nonboot_cpus(void) |
| 951 | { |
| 952 | int cpu, error; |
| 953 | |
| 954 | /* Allow everyone to use the CPU hotplug again */ |
| 955 | cpu_maps_update_begin(); |
| 956 | __cpu_hotplug_enable(); |
| 957 | if (cpumask_empty(frozen_cpus)) |
| 958 | goto out; |
| 959 | |
| 960 | pr_info("Enabling non-boot CPUs ...\n"); |
| 961 | |
| 962 | arch_enable_nonboot_cpus_begin(); |
| 963 | |
| 964 | for_each_cpu(cpu, frozen_cpus) { |
| 965 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
| 966 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
| 967 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
| 968 | if (!error) { |
| 969 | pr_info("CPU%d is up\n", cpu); |
| 970 | continue; |
| 971 | } |
| 972 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
| 973 | } |
| 974 | |
| 975 | arch_enable_nonboot_cpus_end(); |
| 976 | |
| 977 | cpumask_clear(frozen_cpus); |
| 978 | out: |
| 979 | cpu_maps_update_done(); |
| 980 | } |
| 981 | |
| 982 | static int __init alloc_frozen_cpus(void) |
| 983 | { |
| 984 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) |
| 985 | return -ENOMEM; |
| 986 | return 0; |
| 987 | } |
| 988 | core_initcall(alloc_frozen_cpus); |
| 989 | |
| 990 | /* |
| 991 | * When callbacks for CPU hotplug notifications are being executed, we must |
| 992 | * ensure that the state of the system with respect to the tasks being frozen |
| 993 | * or not, as reported by the notification, remains unchanged *throughout the |
| 994 | * duration* of the execution of the callbacks. |
| 995 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. |
| 996 | * |
| 997 | * This synchronization is implemented by mutually excluding regular CPU |
| 998 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ |
| 999 | * Hibernate notifications. |
| 1000 | */ |
| 1001 | static int |
| 1002 | cpu_hotplug_pm_callback(struct notifier_block *nb, |
| 1003 | unsigned long action, void *ptr) |
| 1004 | { |
| 1005 | switch (action) { |
| 1006 | |
| 1007 | case PM_SUSPEND_PREPARE: |
| 1008 | case PM_HIBERNATION_PREPARE: |
| 1009 | cpu_hotplug_disable(); |
| 1010 | break; |
| 1011 | |
| 1012 | case PM_POST_SUSPEND: |
| 1013 | case PM_POST_HIBERNATION: |
| 1014 | cpu_hotplug_enable(); |
| 1015 | break; |
| 1016 | |
| 1017 | default: |
| 1018 | return NOTIFY_DONE; |
| 1019 | } |
| 1020 | |
| 1021 | return NOTIFY_OK; |
| 1022 | } |
| 1023 | |
| 1024 | |
| 1025 | static int __init cpu_hotplug_pm_sync_init(void) |
| 1026 | { |
| 1027 | /* |
| 1028 | * cpu_hotplug_pm_callback has higher priority than x86 |
| 1029 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback |
| 1030 | * to disable cpu hotplug to avoid cpu hotplug race. |
| 1031 | */ |
| 1032 | pm_notifier(cpu_hotplug_pm_callback, 0); |
| 1033 | return 0; |
| 1034 | } |
| 1035 | core_initcall(cpu_hotplug_pm_sync_init); |
| 1036 | |
| 1037 | #endif /* CONFIG_PM_SLEEP_SMP */ |
| 1038 | |
| 1039 | int __boot_cpu_id; |
| 1040 | |
| 1041 | #endif /* CONFIG_SMP */ |
| 1042 | |
| 1043 | /* Boot processor state steps */ |
| 1044 | static struct cpuhp_step cpuhp_bp_states[] = { |
| 1045 | [CPUHP_OFFLINE] = { |
| 1046 | .name = "offline", |
| 1047 | .startup.single = NULL, |
| 1048 | .teardown.single = NULL, |
| 1049 | }, |
| 1050 | #ifdef CONFIG_SMP |
| 1051 | [CPUHP_CREATE_THREADS]= { |
| 1052 | .name = "threads:prepare", |
| 1053 | .startup.single = smpboot_create_threads, |
| 1054 | .teardown.single = NULL, |
| 1055 | .cant_stop = true, |
| 1056 | }, |
| 1057 | [CPUHP_PERF_PREPARE] = { |
| 1058 | .name = "perf:prepare", |
| 1059 | .startup.single = perf_event_init_cpu, |
| 1060 | .teardown.single = perf_event_exit_cpu, |
| 1061 | }, |
| 1062 | [CPUHP_WORKQUEUE_PREP] = { |
| 1063 | .name = "workqueue:prepare", |
| 1064 | .startup.single = workqueue_prepare_cpu, |
| 1065 | .teardown.single = NULL, |
| 1066 | }, |
| 1067 | [CPUHP_HRTIMERS_PREPARE] = { |
| 1068 | .name = "hrtimers:prepare", |
| 1069 | .startup.single = hrtimers_prepare_cpu, |
| 1070 | .teardown.single = hrtimers_dead_cpu, |
| 1071 | }, |
| 1072 | [CPUHP_SMPCFD_PREPARE] = { |
| 1073 | .name = "smpcfd:prepare", |
| 1074 | .startup.single = smpcfd_prepare_cpu, |
| 1075 | .teardown.single = smpcfd_dead_cpu, |
| 1076 | }, |
| 1077 | [CPUHP_RELAY_PREPARE] = { |
| 1078 | .name = "relay:prepare", |
| 1079 | .startup.single = relay_prepare_cpu, |
| 1080 | .teardown.single = NULL, |
| 1081 | }, |
| 1082 | [CPUHP_SLAB_PREPARE] = { |
| 1083 | .name = "slab:prepare", |
| 1084 | .startup.single = slab_prepare_cpu, |
| 1085 | .teardown.single = slab_dead_cpu, |
| 1086 | }, |
| 1087 | [CPUHP_RCUTREE_PREP] = { |
| 1088 | .name = "RCU/tree:prepare", |
| 1089 | .startup.single = rcutree_prepare_cpu, |
| 1090 | .teardown.single = rcutree_dead_cpu, |
| 1091 | }, |
| 1092 | /* |
| 1093 | * On the tear-down path, timers_dead_cpu() must be invoked |
| 1094 | * before blk_mq_queue_reinit_notify() from notify_dead(), |
| 1095 | * otherwise a RCU stall occurs. |
| 1096 | */ |
| 1097 | [CPUHP_TIMERS_DEAD] = { |
| 1098 | .name = "timers:dead", |
| 1099 | .startup.single = NULL, |
| 1100 | .teardown.single = timers_dead_cpu, |
| 1101 | }, |
| 1102 | /* Kicks the plugged cpu into life */ |
| 1103 | [CPUHP_BRINGUP_CPU] = { |
| 1104 | .name = "cpu:bringup", |
| 1105 | .startup.single = bringup_cpu, |
| 1106 | .teardown.single = NULL, |
| 1107 | .cant_stop = true, |
| 1108 | }, |
| 1109 | [CPUHP_AP_SMPCFD_DYING] = { |
| 1110 | .name = "smpcfd:dying", |
| 1111 | .startup.single = NULL, |
| 1112 | .teardown.single = smpcfd_dying_cpu, |
| 1113 | }, |
| 1114 | /* |
| 1115 | * Handled on controll processor until the plugged processor manages |
| 1116 | * this itself. |
| 1117 | */ |
| 1118 | [CPUHP_TEARDOWN_CPU] = { |
| 1119 | .name = "cpu:teardown", |
| 1120 | .startup.single = NULL, |
| 1121 | .teardown.single = takedown_cpu, |
| 1122 | .cant_stop = true, |
| 1123 | }, |
| 1124 | #else |
| 1125 | [CPUHP_BRINGUP_CPU] = { }, |
| 1126 | #endif |
| 1127 | }; |
| 1128 | |
| 1129 | /* Application processor state steps */ |
| 1130 | static struct cpuhp_step cpuhp_ap_states[] = { |
| 1131 | #ifdef CONFIG_SMP |
| 1132 | /* Final state before CPU kills itself */ |
| 1133 | [CPUHP_AP_IDLE_DEAD] = { |
| 1134 | .name = "idle:dead", |
| 1135 | }, |
| 1136 | /* |
| 1137 | * Last state before CPU enters the idle loop to die. Transient state |
| 1138 | * for synchronization. |
| 1139 | */ |
| 1140 | [CPUHP_AP_OFFLINE] = { |
| 1141 | .name = "ap:offline", |
| 1142 | .cant_stop = true, |
| 1143 | }, |
| 1144 | /* First state is scheduler control. Interrupts are disabled */ |
| 1145 | [CPUHP_AP_SCHED_STARTING] = { |
| 1146 | .name = "sched:starting", |
| 1147 | .startup.single = sched_cpu_starting, |
| 1148 | .teardown.single = sched_cpu_dying, |
| 1149 | }, |
| 1150 | [CPUHP_AP_RCUTREE_DYING] = { |
| 1151 | .name = "RCU/tree:dying", |
| 1152 | .startup.single = NULL, |
| 1153 | .teardown.single = rcutree_dying_cpu, |
| 1154 | }, |
| 1155 | /* Entry state on starting. Interrupts enabled from here on. Transient |
| 1156 | * state for synchronsization */ |
| 1157 | [CPUHP_AP_ONLINE] = { |
| 1158 | .name = "ap:online", |
| 1159 | }, |
| 1160 | /* Handle smpboot threads park/unpark */ |
| 1161 | [CPUHP_AP_SMPBOOT_THREADS] = { |
| 1162 | .name = "smpboot/threads:online", |
| 1163 | .startup.single = smpboot_unpark_threads, |
| 1164 | .teardown.single = NULL, |
| 1165 | }, |
| 1166 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
| 1167 | .name = "irq/affinity:online", |
| 1168 | .startup.single = irq_affinity_online_cpu, |
| 1169 | .teardown.single = NULL, |
| 1170 | }, |
| 1171 | [CPUHP_AP_PERF_ONLINE] = { |
| 1172 | .name = "perf:online", |
| 1173 | .startup.single = perf_event_init_cpu, |
| 1174 | .teardown.single = perf_event_exit_cpu, |
| 1175 | }, |
| 1176 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
| 1177 | .name = "workqueue:online", |
| 1178 | .startup.single = workqueue_online_cpu, |
| 1179 | .teardown.single = workqueue_offline_cpu, |
| 1180 | }, |
| 1181 | [CPUHP_AP_RCUTREE_ONLINE] = { |
| 1182 | .name = "RCU/tree:online", |
| 1183 | .startup.single = rcutree_online_cpu, |
| 1184 | .teardown.single = rcutree_offline_cpu, |
| 1185 | }, |
| 1186 | #endif |
| 1187 | /* |
| 1188 | * The dynamically registered state space is here |
| 1189 | */ |
| 1190 | |
| 1191 | #ifdef CONFIG_SMP |
| 1192 | /* Last state is scheduler control setting the cpu active */ |
| 1193 | [CPUHP_AP_ACTIVE] = { |
| 1194 | .name = "sched:active", |
| 1195 | .startup.single = sched_cpu_activate, |
| 1196 | .teardown.single = sched_cpu_deactivate, |
| 1197 | }, |
| 1198 | #endif |
| 1199 | |
| 1200 | /* CPU is fully up and running. */ |
| 1201 | [CPUHP_ONLINE] = { |
| 1202 | .name = "online", |
| 1203 | .startup.single = NULL, |
| 1204 | .teardown.single = NULL, |
| 1205 | }, |
| 1206 | }; |
| 1207 | |
| 1208 | /* Sanity check for callbacks */ |
| 1209 | static int cpuhp_cb_check(enum cpuhp_state state) |
| 1210 | { |
| 1211 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) |
| 1212 | return -EINVAL; |
| 1213 | return 0; |
| 1214 | } |
| 1215 | |
| 1216 | /* |
| 1217 | * Returns a free for dynamic slot assignment of the Online state. The states |
| 1218 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified |
| 1219 | * by having no name assigned. |
| 1220 | */ |
| 1221 | static int cpuhp_reserve_state(enum cpuhp_state state) |
| 1222 | { |
| 1223 | enum cpuhp_state i, end; |
| 1224 | struct cpuhp_step *step; |
| 1225 | |
| 1226 | switch (state) { |
| 1227 | case CPUHP_AP_ONLINE_DYN: |
| 1228 | step = cpuhp_ap_states + CPUHP_AP_ONLINE_DYN; |
| 1229 | end = CPUHP_AP_ONLINE_DYN_END; |
| 1230 | break; |
| 1231 | case CPUHP_BP_PREPARE_DYN: |
| 1232 | step = cpuhp_bp_states + CPUHP_BP_PREPARE_DYN; |
| 1233 | end = CPUHP_BP_PREPARE_DYN_END; |
| 1234 | break; |
| 1235 | default: |
| 1236 | return -EINVAL; |
| 1237 | } |
| 1238 | |
| 1239 | for (i = state; i <= end; i++, step++) { |
| 1240 | if (!step->name) |
| 1241 | return i; |
| 1242 | } |
| 1243 | WARN(1, "No more dynamic states available for CPU hotplug\n"); |
| 1244 | return -ENOSPC; |
| 1245 | } |
| 1246 | |
| 1247 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, |
| 1248 | int (*startup)(unsigned int cpu), |
| 1249 | int (*teardown)(unsigned int cpu), |
| 1250 | bool multi_instance) |
| 1251 | { |
| 1252 | /* (Un)Install the callbacks for further cpu hotplug operations */ |
| 1253 | struct cpuhp_step *sp; |
| 1254 | int ret = 0; |
| 1255 | |
| 1256 | /* |
| 1257 | * If name is NULL, then the state gets removed. |
| 1258 | * |
| 1259 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on |
| 1260 | * the first allocation from these dynamic ranges, so the removal |
| 1261 | * would trigger a new allocation and clear the wrong (already |
| 1262 | * empty) state, leaving the callbacks of the to be cleared state |
| 1263 | * dangling, which causes wreckage on the next hotplug operation. |
| 1264 | */ |
| 1265 | if (name && (state == CPUHP_AP_ONLINE_DYN || |
| 1266 | state == CPUHP_BP_PREPARE_DYN)) { |
| 1267 | ret = cpuhp_reserve_state(state); |
| 1268 | if (ret < 0) |
| 1269 | return ret; |
| 1270 | state = ret; |
| 1271 | } |
| 1272 | sp = cpuhp_get_step(state); |
| 1273 | if (name && sp->name) |
| 1274 | return -EBUSY; |
| 1275 | |
| 1276 | sp->startup.single = startup; |
| 1277 | sp->teardown.single = teardown; |
| 1278 | sp->name = name; |
| 1279 | sp->multi_instance = multi_instance; |
| 1280 | INIT_HLIST_HEAD(&sp->list); |
| 1281 | return ret; |
| 1282 | } |
| 1283 | |
| 1284 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) |
| 1285 | { |
| 1286 | return cpuhp_get_step(state)->teardown.single; |
| 1287 | } |
| 1288 | |
| 1289 | /* |
| 1290 | * Call the startup/teardown function for a step either on the AP or |
| 1291 | * on the current CPU. |
| 1292 | */ |
| 1293 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
| 1294 | struct hlist_node *node) |
| 1295 | { |
| 1296 | struct cpuhp_step *sp = cpuhp_get_step(state); |
| 1297 | int ret; |
| 1298 | |
| 1299 | if ((bringup && !sp->startup.single) || |
| 1300 | (!bringup && !sp->teardown.single)) |
| 1301 | return 0; |
| 1302 | /* |
| 1303 | * The non AP bound callbacks can fail on bringup. On teardown |
| 1304 | * e.g. module removal we crash for now. |
| 1305 | */ |
| 1306 | #ifdef CONFIG_SMP |
| 1307 | if (cpuhp_is_ap_state(state)) |
| 1308 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
| 1309 | else |
| 1310 | ret = cpuhp_invoke_callback(cpu, state, bringup, node); |
| 1311 | #else |
| 1312 | ret = cpuhp_invoke_callback(cpu, state, bringup, node); |
| 1313 | #endif |
| 1314 | BUG_ON(ret && !bringup); |
| 1315 | return ret; |
| 1316 | } |
| 1317 | |
| 1318 | /* |
| 1319 | * Called from __cpuhp_setup_state on a recoverable failure. |
| 1320 | * |
| 1321 | * Note: The teardown callbacks for rollback are not allowed to fail! |
| 1322 | */ |
| 1323 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, |
| 1324 | struct hlist_node *node) |
| 1325 | { |
| 1326 | int cpu; |
| 1327 | |
| 1328 | /* Roll back the already executed steps on the other cpus */ |
| 1329 | for_each_present_cpu(cpu) { |
| 1330 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1331 | int cpustate = st->state; |
| 1332 | |
| 1333 | if (cpu >= failedcpu) |
| 1334 | break; |
| 1335 | |
| 1336 | /* Did we invoke the startup call on that cpu ? */ |
| 1337 | if (cpustate >= state) |
| 1338 | cpuhp_issue_call(cpu, state, false, node); |
| 1339 | } |
| 1340 | } |
| 1341 | |
| 1342 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
| 1343 | struct hlist_node *node, |
| 1344 | bool invoke) |
| 1345 | { |
| 1346 | struct cpuhp_step *sp; |
| 1347 | int cpu; |
| 1348 | int ret; |
| 1349 | |
| 1350 | lockdep_assert_cpus_held(); |
| 1351 | |
| 1352 | sp = cpuhp_get_step(state); |
| 1353 | if (sp->multi_instance == false) |
| 1354 | return -EINVAL; |
| 1355 | |
| 1356 | mutex_lock(&cpuhp_state_mutex); |
| 1357 | |
| 1358 | if (!invoke || !sp->startup.multi) |
| 1359 | goto add_node; |
| 1360 | |
| 1361 | /* |
| 1362 | * Try to call the startup callback for each present cpu |
| 1363 | * depending on the hotplug state of the cpu. |
| 1364 | */ |
| 1365 | for_each_present_cpu(cpu) { |
| 1366 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1367 | int cpustate = st->state; |
| 1368 | |
| 1369 | if (cpustate < state) |
| 1370 | continue; |
| 1371 | |
| 1372 | ret = cpuhp_issue_call(cpu, state, true, node); |
| 1373 | if (ret) { |
| 1374 | if (sp->teardown.multi) |
| 1375 | cpuhp_rollback_install(cpu, state, node); |
| 1376 | goto unlock; |
| 1377 | } |
| 1378 | } |
| 1379 | add_node: |
| 1380 | ret = 0; |
| 1381 | hlist_add_head(node, &sp->list); |
| 1382 | unlock: |
| 1383 | mutex_unlock(&cpuhp_state_mutex); |
| 1384 | return ret; |
| 1385 | } |
| 1386 | |
| 1387 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, |
| 1388 | bool invoke) |
| 1389 | { |
| 1390 | int ret; |
| 1391 | |
| 1392 | cpus_read_lock(); |
| 1393 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); |
| 1394 | cpus_read_unlock(); |
| 1395 | return ret; |
| 1396 | } |
| 1397 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); |
| 1398 | |
| 1399 | /** |
| 1400 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
| 1401 | * @state: The state to setup |
| 1402 | * @invoke: If true, the startup function is invoked for cpus where |
| 1403 | * cpu state >= @state |
| 1404 | * @startup: startup callback function |
| 1405 | * @teardown: teardown callback function |
| 1406 | * @multi_instance: State is set up for multiple instances which get |
| 1407 | * added afterwards. |
| 1408 | * |
| 1409 | * The caller needs to hold cpus read locked while calling this function. |
| 1410 | * Returns: |
| 1411 | * On success: |
| 1412 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN |
| 1413 | * 0 for all other states |
| 1414 | * On failure: proper (negative) error code |
| 1415 | */ |
| 1416 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
| 1417 | const char *name, bool invoke, |
| 1418 | int (*startup)(unsigned int cpu), |
| 1419 | int (*teardown)(unsigned int cpu), |
| 1420 | bool multi_instance) |
| 1421 | { |
| 1422 | int cpu, ret = 0; |
| 1423 | bool dynstate; |
| 1424 | |
| 1425 | lockdep_assert_cpus_held(); |
| 1426 | |
| 1427 | if (cpuhp_cb_check(state) || !name) |
| 1428 | return -EINVAL; |
| 1429 | |
| 1430 | mutex_lock(&cpuhp_state_mutex); |
| 1431 | |
| 1432 | ret = cpuhp_store_callbacks(state, name, startup, teardown, |
| 1433 | multi_instance); |
| 1434 | |
| 1435 | dynstate = state == CPUHP_AP_ONLINE_DYN; |
| 1436 | if (ret > 0 && dynstate) { |
| 1437 | state = ret; |
| 1438 | ret = 0; |
| 1439 | } |
| 1440 | |
| 1441 | if (ret || !invoke || !startup) |
| 1442 | goto out; |
| 1443 | |
| 1444 | /* |
| 1445 | * Try to call the startup callback for each present cpu |
| 1446 | * depending on the hotplug state of the cpu. |
| 1447 | */ |
| 1448 | for_each_present_cpu(cpu) { |
| 1449 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1450 | int cpustate = st->state; |
| 1451 | |
| 1452 | if (cpustate < state) |
| 1453 | continue; |
| 1454 | |
| 1455 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
| 1456 | if (ret) { |
| 1457 | if (teardown) |
| 1458 | cpuhp_rollback_install(cpu, state, NULL); |
| 1459 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
| 1460 | goto out; |
| 1461 | } |
| 1462 | } |
| 1463 | out: |
| 1464 | mutex_unlock(&cpuhp_state_mutex); |
| 1465 | /* |
| 1466 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the |
| 1467 | * dynamically allocated state in case of success. |
| 1468 | */ |
| 1469 | if (!ret && dynstate) |
| 1470 | return state; |
| 1471 | return ret; |
| 1472 | } |
| 1473 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
| 1474 | |
| 1475 | int __cpuhp_setup_state(enum cpuhp_state state, |
| 1476 | const char *name, bool invoke, |
| 1477 | int (*startup)(unsigned int cpu), |
| 1478 | int (*teardown)(unsigned int cpu), |
| 1479 | bool multi_instance) |
| 1480 | { |
| 1481 | int ret; |
| 1482 | |
| 1483 | cpus_read_lock(); |
| 1484 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, |
| 1485 | teardown, multi_instance); |
| 1486 | cpus_read_unlock(); |
| 1487 | return ret; |
| 1488 | } |
| 1489 | EXPORT_SYMBOL(__cpuhp_setup_state); |
| 1490 | |
| 1491 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
| 1492 | struct hlist_node *node, bool invoke) |
| 1493 | { |
| 1494 | struct cpuhp_step *sp = cpuhp_get_step(state); |
| 1495 | int cpu; |
| 1496 | |
| 1497 | BUG_ON(cpuhp_cb_check(state)); |
| 1498 | |
| 1499 | if (!sp->multi_instance) |
| 1500 | return -EINVAL; |
| 1501 | |
| 1502 | cpus_read_lock(); |
| 1503 | mutex_lock(&cpuhp_state_mutex); |
| 1504 | |
| 1505 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
| 1506 | goto remove; |
| 1507 | /* |
| 1508 | * Call the teardown callback for each present cpu depending |
| 1509 | * on the hotplug state of the cpu. This function is not |
| 1510 | * allowed to fail currently! |
| 1511 | */ |
| 1512 | for_each_present_cpu(cpu) { |
| 1513 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1514 | int cpustate = st->state; |
| 1515 | |
| 1516 | if (cpustate >= state) |
| 1517 | cpuhp_issue_call(cpu, state, false, node); |
| 1518 | } |
| 1519 | |
| 1520 | remove: |
| 1521 | hlist_del(node); |
| 1522 | mutex_unlock(&cpuhp_state_mutex); |
| 1523 | cpus_read_unlock(); |
| 1524 | |
| 1525 | return 0; |
| 1526 | } |
| 1527 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); |
| 1528 | |
| 1529 | /** |
| 1530 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
| 1531 | * @state: The state to remove |
| 1532 | * @invoke: If true, the teardown function is invoked for cpus where |
| 1533 | * cpu state >= @state |
| 1534 | * |
| 1535 | * The caller needs to hold cpus read locked while calling this function. |
| 1536 | * The teardown callback is currently not allowed to fail. Think |
| 1537 | * about module removal! |
| 1538 | */ |
| 1539 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
| 1540 | { |
| 1541 | struct cpuhp_step *sp = cpuhp_get_step(state); |
| 1542 | int cpu; |
| 1543 | |
| 1544 | BUG_ON(cpuhp_cb_check(state)); |
| 1545 | |
| 1546 | lockdep_assert_cpus_held(); |
| 1547 | |
| 1548 | mutex_lock(&cpuhp_state_mutex); |
| 1549 | if (sp->multi_instance) { |
| 1550 | WARN(!hlist_empty(&sp->list), |
| 1551 | "Error: Removing state %d which has instances left.\n", |
| 1552 | state); |
| 1553 | goto remove; |
| 1554 | } |
| 1555 | |
| 1556 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
| 1557 | goto remove; |
| 1558 | |
| 1559 | /* |
| 1560 | * Call the teardown callback for each present cpu depending |
| 1561 | * on the hotplug state of the cpu. This function is not |
| 1562 | * allowed to fail currently! |
| 1563 | */ |
| 1564 | for_each_present_cpu(cpu) { |
| 1565 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1566 | int cpustate = st->state; |
| 1567 | |
| 1568 | if (cpustate >= state) |
| 1569 | cpuhp_issue_call(cpu, state, false, NULL); |
| 1570 | } |
| 1571 | remove: |
| 1572 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
| 1573 | mutex_unlock(&cpuhp_state_mutex); |
| 1574 | } |
| 1575 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); |
| 1576 | |
| 1577 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) |
| 1578 | { |
| 1579 | cpus_read_lock(); |
| 1580 | __cpuhp_remove_state_cpuslocked(state, invoke); |
| 1581 | cpus_read_unlock(); |
| 1582 | } |
| 1583 | EXPORT_SYMBOL(__cpuhp_remove_state); |
| 1584 | |
| 1585 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
| 1586 | static ssize_t show_cpuhp_state(struct device *dev, |
| 1587 | struct device_attribute *attr, char *buf) |
| 1588 | { |
| 1589 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| 1590 | |
| 1591 | return sprintf(buf, "%d\n", st->state); |
| 1592 | } |
| 1593 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); |
| 1594 | |
| 1595 | static ssize_t write_cpuhp_target(struct device *dev, |
| 1596 | struct device_attribute *attr, |
| 1597 | const char *buf, size_t count) |
| 1598 | { |
| 1599 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| 1600 | struct cpuhp_step *sp; |
| 1601 | int target, ret; |
| 1602 | |
| 1603 | ret = kstrtoint(buf, 10, &target); |
| 1604 | if (ret) |
| 1605 | return ret; |
| 1606 | |
| 1607 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL |
| 1608 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) |
| 1609 | return -EINVAL; |
| 1610 | #else |
| 1611 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) |
| 1612 | return -EINVAL; |
| 1613 | #endif |
| 1614 | |
| 1615 | ret = lock_device_hotplug_sysfs(); |
| 1616 | if (ret) |
| 1617 | return ret; |
| 1618 | |
| 1619 | mutex_lock(&cpuhp_state_mutex); |
| 1620 | sp = cpuhp_get_step(target); |
| 1621 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; |
| 1622 | mutex_unlock(&cpuhp_state_mutex); |
| 1623 | if (ret) |
| 1624 | goto out; |
| 1625 | |
| 1626 | if (st->state < target) |
| 1627 | ret = do_cpu_up(dev->id, target); |
| 1628 | else |
| 1629 | ret = do_cpu_down(dev->id, target); |
| 1630 | out: |
| 1631 | unlock_device_hotplug(); |
| 1632 | return ret ? ret : count; |
| 1633 | } |
| 1634 | |
| 1635 | static ssize_t show_cpuhp_target(struct device *dev, |
| 1636 | struct device_attribute *attr, char *buf) |
| 1637 | { |
| 1638 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| 1639 | |
| 1640 | return sprintf(buf, "%d\n", st->target); |
| 1641 | } |
| 1642 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
| 1643 | |
| 1644 | static struct attribute *cpuhp_cpu_attrs[] = { |
| 1645 | &dev_attr_state.attr, |
| 1646 | &dev_attr_target.attr, |
| 1647 | NULL |
| 1648 | }; |
| 1649 | |
| 1650 | static const struct attribute_group cpuhp_cpu_attr_group = { |
| 1651 | .attrs = cpuhp_cpu_attrs, |
| 1652 | .name = "hotplug", |
| 1653 | NULL |
| 1654 | }; |
| 1655 | |
| 1656 | static ssize_t show_cpuhp_states(struct device *dev, |
| 1657 | struct device_attribute *attr, char *buf) |
| 1658 | { |
| 1659 | ssize_t cur, res = 0; |
| 1660 | int i; |
| 1661 | |
| 1662 | mutex_lock(&cpuhp_state_mutex); |
| 1663 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
| 1664 | struct cpuhp_step *sp = cpuhp_get_step(i); |
| 1665 | |
| 1666 | if (sp->name) { |
| 1667 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); |
| 1668 | buf += cur; |
| 1669 | res += cur; |
| 1670 | } |
| 1671 | } |
| 1672 | mutex_unlock(&cpuhp_state_mutex); |
| 1673 | return res; |
| 1674 | } |
| 1675 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); |
| 1676 | |
| 1677 | static struct attribute *cpuhp_cpu_root_attrs[] = { |
| 1678 | &dev_attr_states.attr, |
| 1679 | NULL |
| 1680 | }; |
| 1681 | |
| 1682 | static const struct attribute_group cpuhp_cpu_root_attr_group = { |
| 1683 | .attrs = cpuhp_cpu_root_attrs, |
| 1684 | .name = "hotplug", |
| 1685 | NULL |
| 1686 | }; |
| 1687 | |
| 1688 | static int __init cpuhp_sysfs_init(void) |
| 1689 | { |
| 1690 | int cpu, ret; |
| 1691 | |
| 1692 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
| 1693 | &cpuhp_cpu_root_attr_group); |
| 1694 | if (ret) |
| 1695 | return ret; |
| 1696 | |
| 1697 | for_each_possible_cpu(cpu) { |
| 1698 | struct device *dev = get_cpu_device(cpu); |
| 1699 | |
| 1700 | if (!dev) |
| 1701 | continue; |
| 1702 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); |
| 1703 | if (ret) |
| 1704 | return ret; |
| 1705 | } |
| 1706 | return 0; |
| 1707 | } |
| 1708 | device_initcall(cpuhp_sysfs_init); |
| 1709 | #endif |
| 1710 | |
| 1711 | /* |
| 1712 | * cpu_bit_bitmap[] is a special, "compressed" data structure that |
| 1713 | * represents all NR_CPUS bits binary values of 1<<nr. |
| 1714 | * |
| 1715 | * It is used by cpumask_of() to get a constant address to a CPU |
| 1716 | * mask value that has a single bit set only. |
| 1717 | */ |
| 1718 | |
| 1719 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
| 1720 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
| 1721 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
| 1722 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) |
| 1723 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) |
| 1724 | |
| 1725 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
| 1726 | |
| 1727 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), |
| 1728 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), |
| 1729 | #if BITS_PER_LONG > 32 |
| 1730 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), |
| 1731 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), |
| 1732 | #endif |
| 1733 | }; |
| 1734 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
| 1735 | |
| 1736 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; |
| 1737 | EXPORT_SYMBOL(cpu_all_bits); |
| 1738 | |
| 1739 | #ifdef CONFIG_INIT_ALL_POSSIBLE |
| 1740 | struct cpumask __cpu_possible_mask __read_mostly |
| 1741 | = {CPU_BITS_ALL}; |
| 1742 | #else |
| 1743 | struct cpumask __cpu_possible_mask __read_mostly; |
| 1744 | #endif |
| 1745 | EXPORT_SYMBOL(__cpu_possible_mask); |
| 1746 | |
| 1747 | struct cpumask __cpu_online_mask __read_mostly; |
| 1748 | EXPORT_SYMBOL(__cpu_online_mask); |
| 1749 | |
| 1750 | struct cpumask __cpu_present_mask __read_mostly; |
| 1751 | EXPORT_SYMBOL(__cpu_present_mask); |
| 1752 | |
| 1753 | struct cpumask __cpu_active_mask __read_mostly; |
| 1754 | EXPORT_SYMBOL(__cpu_active_mask); |
| 1755 | |
| 1756 | void init_cpu_present(const struct cpumask *src) |
| 1757 | { |
| 1758 | cpumask_copy(&__cpu_present_mask, src); |
| 1759 | } |
| 1760 | |
| 1761 | void init_cpu_possible(const struct cpumask *src) |
| 1762 | { |
| 1763 | cpumask_copy(&__cpu_possible_mask, src); |
| 1764 | } |
| 1765 | |
| 1766 | void init_cpu_online(const struct cpumask *src) |
| 1767 | { |
| 1768 | cpumask_copy(&__cpu_online_mask, src); |
| 1769 | } |
| 1770 | |
| 1771 | /* |
| 1772 | * Activate the first processor. |
| 1773 | */ |
| 1774 | void __init boot_cpu_init(void) |
| 1775 | { |
| 1776 | int cpu = smp_processor_id(); |
| 1777 | |
| 1778 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ |
| 1779 | set_cpu_online(cpu, true); |
| 1780 | set_cpu_active(cpu, true); |
| 1781 | set_cpu_present(cpu, true); |
| 1782 | set_cpu_possible(cpu, true); |
| 1783 | |
| 1784 | #ifdef CONFIG_SMP |
| 1785 | __boot_cpu_id = cpu; |
| 1786 | #endif |
| 1787 | } |
| 1788 | |
| 1789 | /* |
| 1790 | * Must be called _AFTER_ setting up the per_cpu areas |
| 1791 | */ |
| 1792 | void __init boot_cpu_state_init(void) |
| 1793 | { |
| 1794 | per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE; |
| 1795 | } |