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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 | /* * Copyright (c) 2017 Wind River Systems, Inc. * * SPDX-License-Identifier: Apache-2.0 */ /** * @file * * @brief Kernel asynchronous event polling interface. * * This polling mechanism allows waiting on multiple events concurrently, * either events triggered directly, or from kernel objects or other kernel * constructs. */ #include <kernel.h> #include <kernel_structs.h> #include <kernel_internal.h> #include <wait_q.h> #include <ksched.h> #include <syscall_handler.h> #include <sys/slist.h> #include <sys/dlist.h> #include <sys/util.h> #include <sys/__assert.h> #include <stdbool.h> /* Single subsystem lock. Locking per-event would be better on highly * contended SMP systems, but the original locking scheme here is * subtle (it relies on releasing/reacquiring the lock in areas for * latency control and it's sometimes hard to see exactly what data is * "inside" a given critical section). Do the synchronization port * later as an optimization. */ static struct k_spinlock lock; void k_poll_event_init(struct k_poll_event *event, u32_t type, int mode, void *obj) { __ASSERT(mode == K_POLL_MODE_NOTIFY_ONLY, "only NOTIFY_ONLY mode is supported\n"); __ASSERT(type < (BIT(_POLL_NUM_TYPES)), "invalid type\n"); __ASSERT(obj != NULL, "must provide an object\n"); event->poller = NULL; /* event->tag is left uninitialized: the user will set it if needed */ event->type = type; event->state = K_POLL_STATE_NOT_READY; event->mode = mode; event->unused = 0U; event->obj = obj; } /* must be called with interrupts locked */ static inline bool is_condition_met(struct k_poll_event *event, u32_t *state) { switch (event->type) { case K_POLL_TYPE_SEM_AVAILABLE: if (k_sem_count_get(event->sem) > 0) { *state = K_POLL_STATE_SEM_AVAILABLE; return true; } break; case K_POLL_TYPE_DATA_AVAILABLE: if (!k_queue_is_empty(event->queue)) { *state = K_POLL_STATE_FIFO_DATA_AVAILABLE; return true; } break; case K_POLL_TYPE_SIGNAL: if (event->signal->signaled != 0U) { *state = K_POLL_STATE_SIGNALED; return true; } break; case K_POLL_TYPE_IGNORE: break; default: __ASSERT(false, "invalid event type (0x%x)\n", event->type); break; } return false; } static inline void add_event(sys_dlist_t *events, struct k_poll_event *event, struct _poller *poller) { struct k_poll_event *pending; pending = (struct k_poll_event *)sys_dlist_peek_tail(events); if ((pending == NULL) || z_is_t1_higher_prio_than_t2(pending->poller->thread, poller->thread)) { sys_dlist_append(events, &event->_node); return; } SYS_DLIST_FOR_EACH_CONTAINER(events, pending, _node) { if (z_is_t1_higher_prio_than_t2(poller->thread, pending->poller->thread)) { sys_dlist_insert(&pending->_node, &event->_node); return; } } sys_dlist_append(events, &event->_node); } /* must be called with interrupts locked */ static inline int register_event(struct k_poll_event *event, struct _poller *poller) { switch (event->type) { case K_POLL_TYPE_SEM_AVAILABLE: __ASSERT(event->sem != NULL, "invalid semaphore\n"); add_event(&event->sem->poll_events, event, poller); break; case K_POLL_TYPE_DATA_AVAILABLE: __ASSERT(event->queue != NULL, "invalid queue\n"); add_event(&event->queue->poll_events, event, poller); break; case K_POLL_TYPE_SIGNAL: __ASSERT(event->signal != NULL, "invalid poll signal\n"); add_event(&event->signal->poll_events, event, poller); break; case K_POLL_TYPE_IGNORE: /* nothing to do */ break; default: __ASSERT(false, "invalid event type\n"); break; } event->poller = poller; return 0; } /* must be called with interrupts locked */ static inline void clear_event_registration(struct k_poll_event *event) { bool remove = false; event->poller = NULL; switch (event->type) { case K_POLL_TYPE_SEM_AVAILABLE: __ASSERT(event->sem != NULL, "invalid semaphore\n"); remove = true; break; case K_POLL_TYPE_DATA_AVAILABLE: __ASSERT(event->queue != NULL, "invalid queue\n"); remove = true; break; case K_POLL_TYPE_SIGNAL: __ASSERT(event->signal != NULL, "invalid poll signal\n"); remove = true; break; case K_POLL_TYPE_IGNORE: /* nothing to do */ break; default: __ASSERT(false, "invalid event type\n"); break; } if (remove && sys_dnode_is_linked(&event->_node)) { sys_dlist_remove(&event->_node); } } /* must be called with interrupts locked */ static inline void clear_event_registrations(struct k_poll_event *events, int num_events, k_spinlock_key_t key) { while (num_events--) { clear_event_registration(&events[num_events]); k_spin_unlock(&lock, key); key = k_spin_lock(&lock); } } static inline void set_event_ready(struct k_poll_event *event, u32_t state) { event->poller = NULL; event->state |= state; } static inline int register_events(struct k_poll_event *events, int num_events, struct _poller *poller, bool just_check) { int events_registered = 0; for (int ii = 0; ii < num_events; ii++) { k_spinlock_key_t key; u32_t state; key = k_spin_lock(&lock); if (is_condition_met(&events[ii], &state)) { set_event_ready(&events[ii], state); poller->is_polling = false; } else if (!just_check && poller->is_polling) { int rc = register_event(&events[ii], poller); if (rc == 0) { events_registered += 1; } else { __ASSERT(false, "unexpected return code\n"); } } k_spin_unlock(&lock, key); } return events_registered; } static int k_poll_poller_cb(struct k_poll_event *event, u32_t state) { struct k_thread *thread = event->poller->thread; __ASSERT(thread != NULL, "poller should have a thread\n"); if (!z_is_thread_pending(thread)) { return 0; } if (z_is_thread_timeout_expired(thread)) { return -EAGAIN; } z_unpend_thread(thread); arch_thread_return_value_set(thread, state == K_POLL_STATE_CANCELLED ? -EINTR : 0); if (!z_is_thread_ready(thread)) { return 0; } z_ready_thread(thread); return 0; } int z_impl_k_poll(struct k_poll_event *events, int num_events, s32_t timeout) { int events_registered; k_spinlock_key_t key; struct _poller poller = { .is_polling = true, .thread = _current, .cb = k_poll_poller_cb }; __ASSERT(!arch_is_in_isr(), ""); __ASSERT(events != NULL, "NULL events\n"); __ASSERT(num_events >= 0, "<0 events\n"); events_registered = register_events(events, num_events, &poller, (timeout == K_NO_WAIT)); key = k_spin_lock(&lock); /* * If we're not polling anymore, it means that at least one event * condition is met, either when looping through the events here or * because one of the events registered has had its state changed. */ if (!poller.is_polling) { clear_event_registrations(events, events_registered, key); k_spin_unlock(&lock, key); return 0; } poller.is_polling = false; if (timeout == K_NO_WAIT) { k_spin_unlock(&lock, key); return -EAGAIN; } _wait_q_t wait_q = Z_WAIT_Q_INIT(&wait_q); int swap_rc = z_pend_curr(&lock, key, &wait_q, timeout); /* * Clear all event registrations. If events happen while we're in this * loop, and we already had one that triggered, that's OK: they will * end up in the list of events that are ready; if we timed out, and * events happen while we're in this loop, that is OK as well since * we've already know the return code (-EAGAIN), and even if they are * added to the list of events that occurred, the user has to check the * return code first, which invalidates the whole list of event states. */ key = k_spin_lock(&lock); clear_event_registrations(events, events_registered, key); k_spin_unlock(&lock, key); return swap_rc; } #ifdef CONFIG_USERSPACE static inline int z_vrfy_k_poll(struct k_poll_event *events, int num_events, s32_t timeout) { int ret; k_spinlock_key_t key; struct k_poll_event *events_copy = NULL; u32_t bounds; /* Validate the events buffer and make a copy of it in an * allocated kernel-side buffer. */ if (Z_SYSCALL_VERIFY(num_events >= 0)) { ret = -EINVAL; goto out; } if (Z_SYSCALL_VERIFY_MSG(!u32_mul_overflow(num_events, sizeof(struct k_poll_event), &bounds), "num_events too large")) { ret = -EINVAL; goto out; } events_copy = z_thread_malloc(bounds); if (!events_copy) { ret = -ENOMEM; goto out; } key = k_spin_lock(&lock); if (Z_SYSCALL_MEMORY_WRITE(events, bounds)) { k_spin_unlock(&lock, key); goto oops_free; } (void)memcpy(events_copy, events, bounds); k_spin_unlock(&lock, key); /* Validate what's inside events_copy */ for (int i = 0; i < num_events; i++) { struct k_poll_event *e = &events_copy[i]; if (Z_SYSCALL_VERIFY(e->mode == K_POLL_MODE_NOTIFY_ONLY)) { ret = -EINVAL; goto out_free; } switch (e->type) { case K_POLL_TYPE_IGNORE: break; case K_POLL_TYPE_SIGNAL: Z_OOPS(Z_SYSCALL_OBJ(e->signal, K_OBJ_POLL_SIGNAL)); break; case K_POLL_TYPE_SEM_AVAILABLE: Z_OOPS(Z_SYSCALL_OBJ(e->sem, K_OBJ_SEM)); break; case K_POLL_TYPE_DATA_AVAILABLE: Z_OOPS(Z_SYSCALL_OBJ(e->queue, K_OBJ_QUEUE)); break; default: ret = -EINVAL; goto out_free; } } ret = k_poll(events_copy, num_events, timeout); (void)memcpy((void *)events, events_copy, bounds); out_free: k_free(events_copy); out: return ret; oops_free: k_free(events_copy); Z_OOPS(1); } #include <syscalls/k_poll_mrsh.c> #endif /* must be called with interrupts locked */ static int signal_poll_event(struct k_poll_event *event, u32_t state) { struct _poller *poller = event->poller; int retcode = 0; if (poller) { if (poller->cb != NULL) { retcode = poller->cb(event, state); } poller->is_polling = false; if (retcode < 0) { return retcode; } } set_event_ready(event, state); return retcode; } void z_handle_obj_poll_events(sys_dlist_t *events, u32_t state) { struct k_poll_event *poll_event; poll_event = (struct k_poll_event *)sys_dlist_get(events); if (poll_event != NULL) { (void) signal_poll_event(poll_event, state); } } void z_impl_k_poll_signal_init(struct k_poll_signal *signal) { sys_dlist_init(&signal->poll_events); signal->signaled = 0U; /* signal->result is left unitialized */ z_object_init(signal); } #ifdef CONFIG_USERSPACE static inline void z_vrfy_k_poll_signal_init(struct k_poll_signal *signal) { Z_OOPS(Z_SYSCALL_OBJ_INIT(signal, K_OBJ_POLL_SIGNAL)); z_impl_k_poll_signal_init(signal); } #include <syscalls/k_poll_signal_init_mrsh.c> #endif void z_impl_k_poll_signal_check(struct k_poll_signal *signal, unsigned int *signaled, int *result) { *signaled = signal->signaled; *result = signal->result; } #ifdef CONFIG_USERSPACE void z_vrfy_k_poll_signal_check(struct k_poll_signal *signal, unsigned int *signaled, int *result) { Z_OOPS(Z_SYSCALL_OBJ(signal, K_OBJ_POLL_SIGNAL)); Z_OOPS(Z_SYSCALL_MEMORY_WRITE(signaled, sizeof(unsigned int))); Z_OOPS(Z_SYSCALL_MEMORY_WRITE(result, sizeof(int))); z_impl_k_poll_signal_check(signal, signaled, result); } #include <syscalls/k_poll_signal_check_mrsh.c> #endif int z_impl_k_poll_signal_raise(struct k_poll_signal *signal, int result) { k_spinlock_key_t key = k_spin_lock(&lock); struct k_poll_event *poll_event; signal->result = result; signal->signaled = 1U; poll_event = (struct k_poll_event *)sys_dlist_get(&signal->poll_events); if (poll_event == NULL) { k_spin_unlock(&lock, key); return 0; } int rc = signal_poll_event(poll_event, K_POLL_STATE_SIGNALED); z_reschedule(&lock, key); return rc; } #ifdef CONFIG_USERSPACE static inline int z_vrfy_k_poll_signal_raise(struct k_poll_signal *signal, int result) { Z_OOPS(Z_SYSCALL_OBJ(signal, K_OBJ_POLL_SIGNAL)); return z_impl_k_poll_signal_raise(signal, result); } #include <syscalls/k_poll_signal_raise_mrsh.c> static inline void z_vrfy_k_poll_signal_reset(struct k_poll_signal *signal) { Z_OOPS(Z_SYSCALL_OBJ(signal, K_OBJ_POLL_SIGNAL)); z_impl_k_poll_signal_reset(signal); } #include <syscalls/k_poll_signal_reset_mrsh.c> #endif static void triggered_work_handler(struct k_work *work) { k_work_handler_t handler; struct k_work_poll *twork = CONTAINER_OF(work, struct k_work_poll, work); /* * If callback is not set, the k_work_poll_submit_to_queue() * already cleared event registrations. */ if (twork->poller.cb != NULL) { k_spinlock_key_t key; key = k_spin_lock(&lock); clear_event_registrations(twork->events, twork->num_events, key); k_spin_unlock(&lock, key); } /* Drop work ownership and execute real handler. */ handler = twork->real_handler; twork->poller.thread = NULL; handler(work); } static void triggered_work_expiration_handler(struct _timeout *timeout) { struct k_work_poll *twork = CONTAINER_OF(timeout, struct k_work_poll, timeout); struct k_work_q *work_q = CONTAINER_OF(twork->poller.thread, struct k_work_q, thread); twork->poller.is_polling = false; twork->poll_result = -EAGAIN; k_work_submit_to_queue(work_q, &twork->work); } static int triggered_work_poller_cb(struct k_poll_event *event, u32_t status) { struct _poller *poller = event->poller; if (poller->is_polling && poller->thread) { struct k_work_poll *twork = CONTAINER_OF(poller, struct k_work_poll, poller); struct k_work_q *work_q = CONTAINER_OF(poller->thread, struct k_work_q, thread); z_abort_timeout(&twork->timeout); twork->poll_result = 0; k_work_submit_to_queue(work_q, &twork->work); } return 0; } static int triggered_work_cancel(struct k_work_poll *work, k_spinlock_key_t key) { /* Check if the work waits for event. */ if (work->poller.is_polling && work->poller.cb != NULL) { /* Remove timeout associated with the work. */ z_abort_timeout(&work->timeout); /* * Prevent work execution if event arrives while we will be * clearing registrations. */ work->poller.cb = NULL; /* Clear registrations and work ownership. */ clear_event_registrations(work->events, work->num_events, key); work->poller.thread = NULL; return 0; } /* * If we reached here, the work is either being registered in * the k_work_poll_submit_to_queue(), executed or is pending. * Only in the last case we have a chance to cancel it, but * unfortunately there is no public API performing this task. */ return -EINVAL; } void k_work_poll_init(struct k_work_poll *work, k_work_handler_t handler) { k_work_init(&work->work, triggered_work_handler); work->events = NULL; work->poller.thread = NULL; work->real_handler = handler; z_init_timeout(&work->timeout); } int k_work_poll_submit_to_queue(struct k_work_q *work_q, struct k_work_poll *work, struct k_poll_event *events, int num_events, s32_t timeout) { int events_registered; k_spinlock_key_t key; __ASSERT(work_q != NULL, "NULL work_q\n"); __ASSERT(work != NULL, "NULL work\n"); __ASSERT(events != NULL, "NULL events\n"); __ASSERT(num_events > 0, "zero events\n"); /* Take overship of the work if it is possible. */ key = k_spin_lock(&lock); if (work->poller.thread != NULL) { if (work->poller.thread == &work_q->thread) { int retval; retval = triggered_work_cancel(work, key); if (retval < 0) { k_spin_unlock(&lock, key); return retval; } } else { k_spin_unlock(&lock, key); return -EADDRINUSE; } } work->poller.is_polling = true; work->poller.thread = &work_q->thread; work->poller.cb = NULL; k_spin_unlock(&lock, key); /* Save list of events. */ work->events = events; work->num_events = num_events; /* Clear result */ work->poll_result = -EINPROGRESS; /* Register events */ events_registered = register_events(events, num_events, &work->poller, false); key = k_spin_lock(&lock); if (work->poller.is_polling && timeout != K_NO_WAIT) { /* * Poller is still polling. * No event is ready and all are watched. */ __ASSERT(num_events == events_registered, "Some events were not registered!\n"); /* Setup timeout if such action is requested */ if (timeout != K_FOREVER) { z_add_timeout(&work->timeout, triggered_work_expiration_handler, k_ms_to_ticks_ceil32(timeout)); } /* From now, any event will result in submitted work. */ work->poller.cb = triggered_work_poller_cb; k_spin_unlock(&lock, key); return 0; } /* * The K_NO_WAIT timeout was specified or at least one event was ready * at registration time or changed state since registration. Hopefully, * the poller->cb was not set, so work was not submitted to workqueue. */ /* * If poller is still polling, no watched event occurred. This means * we reached here due to K_NO_WAIT timeout "expiration". */ if (work->poller.is_polling) { work->poller.is_polling = false; work->poll_result = -EAGAIN; } else { work->poll_result = 0; } /* Clear registrations. */ clear_event_registrations(events, events_registered, key); k_spin_unlock(&lock, key); /* Submit work. */ k_work_submit_to_queue(work_q, &work->work); return 0; } int k_work_poll_cancel(struct k_work_poll *work) { k_spinlock_key_t key; int retval; /* Check if the work was submitted. */ if (work == NULL || work->poller.thread == NULL) { return -EINVAL; } key = k_spin_lock(&lock); retval = triggered_work_cancel(work, key); k_spin_unlock(&lock, key); return retval; } |