| /* |
| * Copyright (c) 2008-2009 Travis Geiselbrecht |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining |
| * a copy of this software and associated documentation files |
| * (the "Software"), to deal in the Software without restriction, |
| * including without limitation the rights to use, copy, modify, merge, |
| * publish, distribute, sublicense, and/or sell copies of the Software, |
| * and to permit persons to whom the Software is furnished to do so, |
| * subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be |
| * included in all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. |
| * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY |
| * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, |
| * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE |
| * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| */ |
| |
| /** |
| * @file |
| * @brief Kernel threading |
| * |
| * This file is the core kernel threading interface. |
| * |
| * @defgroup thread Threads |
| * @{ |
| */ |
| #include <debug.h> |
| #include <list.h> |
| #include <malloc.h> |
| #include <string.h> |
| #include <err.h> |
| #include <kernel/thread.h> |
| #include <kernel/timer.h> |
| #include <kernel/dpc.h> |
| #include <platform.h> |
| |
| #if DEBUGLEVEL > 1 |
| #define THREAD_CHECKS 1 |
| #endif |
| |
| #if THREAD_STATS |
| struct thread_stats thread_stats; |
| #endif |
| |
| /* global thread list */ |
| static struct list_node thread_list; |
| |
| /* the current thread */ |
| thread_t *current_thread; |
| |
| /* the global critical section count */ |
| int critical_section_count = 1; |
| |
| /* the run queue */ |
| static struct list_node run_queue[NUM_PRIORITIES]; |
| static uint32_t run_queue_bitmap; |
| |
| /* the bootstrap thread (statically allocated) */ |
| static thread_t bootstrap_thread; |
| |
| /* the idle thread */ |
| thread_t *idle_thread; |
| |
| /* local routines */ |
| static void thread_resched(void); |
| static void idle_thread_routine(void) __NO_RETURN; |
| |
| #if PLATFORM_HAS_DYNAMIC_TIMER |
| /* preemption timer */ |
| static timer_t preempt_timer; |
| #endif |
| |
| /* run queue manipulation */ |
| static void insert_in_run_queue_head(thread_t *t) |
| { |
| #if THREAD_CHECKS |
| ASSERT(t->magic == THREAD_MAGIC); |
| ASSERT(t->state == THREAD_READY); |
| ASSERT(!list_in_list(&t->queue_node)); |
| ASSERT(in_critical_section()); |
| #endif |
| |
| list_add_head(&run_queue[t->priority], &t->queue_node); |
| run_queue_bitmap |= (1<<t->priority); |
| } |
| |
| static void insert_in_run_queue_tail(thread_t *t) |
| { |
| #if THREAD_CHECKS |
| ASSERT(t->magic == THREAD_MAGIC); |
| ASSERT(t->state == THREAD_READY); |
| ASSERT(!list_in_list(&t->queue_node)); |
| ASSERT(in_critical_section()); |
| #endif |
| |
| list_add_tail(&run_queue[t->priority], &t->queue_node); |
| run_queue_bitmap |= (1<<t->priority); |
| } |
| |
| static void init_thread_struct(thread_t *t, const char *name) |
| { |
| memset(t, 0, sizeof(thread_t)); |
| t->magic = THREAD_MAGIC; |
| strlcpy(t->name, name, sizeof(t->name)); |
| } |
| |
| /** |
| * @brief Create a new thread |
| * |
| * This function creates a new thread. The thread is initially suspended, so you |
| * need to call thread_resume() to execute it. |
| * |
| * @param name Name of thread |
| * @param entry Entry point of thread |
| * @param arg Arbitrary argument passed to entry() |
| * @param priority Execution priority for the thread. |
| * @param stack_size Stack size for the thread. |
| * |
| * Thread priority is an integer from 0 (lowest) to 31 (highest). Some standard |
| * prioritys are defined in <kernel/thread.h>: |
| * |
| * HIGHEST_PRIORITY |
| * DPC_PRIORITY |
| * HIGH_PRIORITY |
| * DEFAULT_PRIORITY |
| * LOW_PRIORITY |
| * IDLE_PRIORITY |
| * LOWEST_PRIORITY |
| * |
| * Stack size is typically set to DEFAULT_STACK_SIZE |
| * |
| * @return Pointer to thread object, or NULL on failure. |
| */ |
| thread_t *thread_create(const char *name, thread_start_routine entry, void *arg, int priority, size_t stack_size) |
| { |
| thread_t *t; |
| |
| t = malloc(sizeof(thread_t)); |
| if (!t) |
| return NULL; |
| |
| init_thread_struct(t, name); |
| |
| t->entry = entry; |
| t->arg = arg; |
| t->priority = priority; |
| t->saved_critical_section_count = 1; /* we always start inside a critical section */ |
| t->state = THREAD_SUSPENDED; |
| t->blocking_wait_queue = NULL; |
| t->wait_queue_block_ret = NO_ERROR; |
| |
| /* create the stack */ |
| t->stack = malloc(stack_size); |
| if (!t->stack) { |
| free(t); |
| return NULL; |
| } |
| |
| t->stack_size = stack_size; |
| |
| /* inheirit thread local storage from the parent */ |
| int i; |
| for (i=0; i < MAX_TLS_ENTRY; i++) |
| t->tls[i] = current_thread->tls[i]; |
| |
| /* set up the initial stack frame */ |
| arch_thread_initialize(t); |
| |
| /* add it to the global thread list */ |
| enter_critical_section(); |
| list_add_head(&thread_list, &t->thread_list_node); |
| exit_critical_section(); |
| |
| return t; |
| } |
| |
| /** |
| * @brief Make a suspended thread executable. |
| * |
| * This function is typically called to start a thread which has just been |
| * created with thread_create() |
| * |
| * @param t Thread to resume |
| * |
| * @return NO_ERROR on success, ERR_NOT_SUSPENDED if thread was not suspended. |
| */ |
| status_t thread_resume(thread_t *t) |
| { |
| #if THREAD_CHECKS |
| ASSERT(t->magic == THREAD_MAGIC); |
| ASSERT(t->state != THREAD_DEATH); |
| #endif |
| |
| if (t->state == THREAD_READY || t->state == THREAD_RUNNING) |
| return ERR_NOT_SUSPENDED; |
| |
| enter_critical_section(); |
| t->state = THREAD_READY; |
| insert_in_run_queue_head(t); |
| thread_yield(); |
| exit_critical_section(); |
| |
| return NO_ERROR; |
| } |
| |
| static void thread_cleanup_dpc(void *thread) |
| { |
| thread_t *t = (thread_t *)thread; |
| |
| // dprintf(SPEW, "thread_cleanup_dpc: thread %p (%s)\n", t, t->name); |
| |
| #if THREAD_CHECKS |
| ASSERT(t->state == THREAD_DEATH); |
| ASSERT(t->blocking_wait_queue == NULL); |
| ASSERT(!list_in_list(&t->queue_node)); |
| #endif |
| |
| /* remove it from the master thread list */ |
| enter_critical_section(); |
| list_delete(&t->thread_list_node); |
| exit_critical_section(); |
| |
| /* free its stack and the thread structure itself */ |
| if (t->stack) |
| free(t->stack); |
| |
| free(t); |
| } |
| |
| /** |
| * @brief Terminate the current thread |
| * |
| * Current thread exits with the specified return code. |
| * |
| * This function does not return. |
| */ |
| void thread_exit(int retcode) |
| { |
| #if THREAD_CHECKS |
| ASSERT(current_thread->magic == THREAD_MAGIC); |
| ASSERT(current_thread->state == THREAD_RUNNING); |
| #endif |
| |
| // dprintf("thread_exit: current %p\n", current_thread); |
| |
| enter_critical_section(); |
| |
| /* enter the dead state */ |
| current_thread->state = THREAD_DEATH; |
| current_thread->retcode = retcode; |
| |
| /* schedule a dpc to clean ourselves up */ |
| dpc_queue(thread_cleanup_dpc, (void *)current_thread, DPC_FLAG_NORESCHED); |
| |
| /* reschedule */ |
| thread_resched(); |
| |
| panic("somehow fell through thread_exit()\n"); |
| } |
| |
| static void idle_thread_routine(void) |
| { |
| for(;;) |
| arch_idle(); |
| } |
| |
| /** |
| * @brief Cause another thread to be executed. |
| * |
| * Internal reschedule routine. The current thread needs to already be in whatever |
| * state and queues it needs to be in. This routine simply picks the next thread and |
| * switches to it. |
| * |
| * This is probably not the function you're looking for. See |
| * thread_yield() instead. |
| */ |
| void thread_resched(void) |
| { |
| thread_t *oldthread; |
| thread_t *newthread; |
| |
| // dprintf("thread_resched: current %p: ", current_thread); |
| // dump_thread(current_thread); |
| |
| #if THREAD_CHECKS |
| ASSERT(in_critical_section()); |
| #endif |
| |
| #if THREAD_STATS |
| thread_stats.reschedules++; |
| #endif |
| |
| oldthread = current_thread; |
| |
| // at the moment, can't deal with more than 32 priority levels |
| ASSERT(NUM_PRIORITIES <= 32); |
| |
| // should at least find the idle thread |
| #if THREAD_CHECKS |
| ASSERT(run_queue_bitmap != 0); |
| #endif |
| |
| int next_queue = HIGHEST_PRIORITY - __builtin_clz(run_queue_bitmap) - (32 - NUM_PRIORITIES); |
| //dprintf(SPEW, "bitmap 0x%x, next %d\n", run_queue_bitmap, next_queue); |
| |
| newthread = list_remove_head_type(&run_queue[next_queue], thread_t, queue_node); |
| |
| #if THREAD_CHECKS |
| ASSERT(newthread); |
| #endif |
| |
| if (list_is_empty(&run_queue[next_queue])) |
| run_queue_bitmap &= ~(1<<next_queue); |
| |
| #if 0 |
| // XXX make this more efficient |
| newthread = NULL; |
| for (i=HIGHEST_PRIORITY; i >= LOWEST_PRIORITY; i--) { |
| newthread = list_remove_head_type(&run_queue[i], thread_t, queue_node); |
| if (newthread) |
| break; |
| } |
| #endif |
| |
| // dprintf("newthread: "); |
| // dump_thread(newthread); |
| |
| newthread->state = THREAD_RUNNING; |
| |
| if (newthread == oldthread) |
| return; |
| |
| /* set up quantum for the new thread if it was consumed */ |
| if (newthread->remaining_quantum <= 0) { |
| newthread->remaining_quantum = 5; // XXX make this smarter |
| } |
| |
| #if THREAD_STATS |
| thread_stats.context_switches++; |
| |
| if (oldthread == idle_thread) { |
| bigtime_t now = current_time_hires(); |
| thread_stats.idle_time += now - thread_stats.last_idle_timestamp; |
| } |
| if (newthread == idle_thread) { |
| thread_stats.last_idle_timestamp = current_time_hires(); |
| } |
| #endif |
| |
| #if THREAD_CHECKS |
| ASSERT(critical_section_count > 0); |
| ASSERT(newthread->saved_critical_section_count > 0); |
| #endif |
| |
| #if PLATFORM_HAS_DYNAMIC_TIMER |
| /* if we're switching from idle to a real thread, set up a periodic |
| * timer to run our preemption tick. |
| */ |
| if (oldthread == idle_thread) { |
| timer_set_periodic(&preempt_timer, 10, (timer_callback)thread_timer_tick, NULL); |
| } else if (newthread == idle_thread) { |
| timer_cancel(&preempt_timer); |
| } |
| #endif |
| |
| /* do the switch */ |
| oldthread->saved_critical_section_count = critical_section_count; |
| current_thread = newthread; |
| critical_section_count = newthread->saved_critical_section_count; |
| arch_context_switch(oldthread, newthread); |
| } |
| |
| /** |
| * @brief Yield the cpu to another thread |
| * |
| * This function places the current thread at the end of the run queue |
| * and yields the cpu to another waiting thread (if any.) |
| * |
| * This function will return at some later time. Possibly immediately if |
| * no other threads are waiting to execute. |
| */ |
| void thread_yield(void) |
| { |
| #if THREAD_CHECKS |
| ASSERT(current_thread->magic == THREAD_MAGIC); |
| ASSERT(current_thread->state == THREAD_RUNNING); |
| #endif |
| |
| enter_critical_section(); |
| |
| #if THREAD_STATS |
| thread_stats.yields++; |
| #endif |
| |
| /* we are yielding the cpu, so stick ourselves into the tail of the run queue and reschedule */ |
| current_thread->state = THREAD_READY; |
| current_thread->remaining_quantum = 0; |
| insert_in_run_queue_tail(current_thread); |
| thread_resched(); |
| |
| exit_critical_section(); |
| } |
| |
| /** |
| * @brief Briefly yield cpu to another thread |
| * |
| * This function is similar to thread_yield(), except that it will |
| * restart more quickly. |
| * |
| * This function places the current thread at the head of the run |
| * queue and then yields the cpu to another thread. |
| * |
| * Exception: If the time slice for this thread has expired, then |
| * the thread goes to the end of the run queue. |
| * |
| * This function will return at some later time. Possibly immediately if |
| * no other threads are waiting to execute. |
| */ |
| void thread_preempt(void) |
| { |
| #if THREAD_CHECKS |
| ASSERT(current_thread->magic == THREAD_MAGIC); |
| ASSERT(current_thread->state == THREAD_RUNNING); |
| #endif |
| |
| enter_critical_section(); |
| |
| #if THREAD_STATS |
| if (current_thread != idle_thread) |
| thread_stats.preempts++; /* only track when a meaningful preempt happens */ |
| #endif |
| |
| /* we are being preempted, so we get to go back into the front of the run queue if we have quantum left */ |
| current_thread->state = THREAD_READY; |
| if (current_thread->remaining_quantum > 0) |
| insert_in_run_queue_head(current_thread); |
| else |
| insert_in_run_queue_tail(current_thread); /* if we're out of quantum, go to the tail of the queue */ |
| thread_resched(); |
| |
| exit_critical_section(); |
| } |
| |
| /** |
| * @brief Suspend thread until woken. |
| * |
| * This function schedules another thread to execute. This function does not |
| * return until the thread is made runable again by some other module. |
| * |
| * You probably don't want to call this function directly; it's meant to be called |
| * from other modules, such as mutex, which will presumably set the thread's |
| * state to blocked and add it to some queue or another. |
| */ |
| void thread_block(void) |
| { |
| #if THREAD_CHECKS |
| ASSERT(current_thread->magic == THREAD_MAGIC); |
| ASSERT(current_thread->state == THREAD_BLOCKED); |
| #endif |
| |
| enter_critical_section(); |
| |
| /* we are blocking on something. the blocking code should have already stuck us on a queue */ |
| thread_resched(); |
| |
| exit_critical_section(); |
| } |
| |
| enum handler_return thread_timer_tick(void) |
| { |
| if (current_thread == idle_thread) |
| return INT_NO_RESCHEDULE; |
| |
| current_thread->remaining_quantum--; |
| if (current_thread->remaining_quantum <= 0) |
| return INT_RESCHEDULE; |
| else |
| return INT_NO_RESCHEDULE; |
| } |
| |
| /* timer callback to wake up a sleeping thread */ |
| static enum handler_return thread_sleep_handler(timer_t *timer, time_t now, void *arg) |
| { |
| thread_t *t = (thread_t *)arg; |
| |
| #if THREAD_CHECKS |
| ASSERT(t->magic == THREAD_MAGIC); |
| ASSERT(t->state == THREAD_SLEEPING); |
| #endif |
| |
| t->state = THREAD_READY; |
| insert_in_run_queue_head(t); |
| |
| return INT_RESCHEDULE; |
| } |
| |
| /** |
| * @brief Put thread to sleep; delay specified in ms |
| * |
| * This function puts the current thread to sleep until the specified |
| * delay in ms has expired. |
| * |
| * Note that this function could sleep for longer than the specified delay if |
| * other threads are running. When the timer expires, this thread will |
| * be placed at the head of the run queue. |
| */ |
| void thread_sleep(time_t delay) |
| { |
| timer_t timer; |
| |
| #if THREAD_CHECKS |
| ASSERT(current_thread->magic == THREAD_MAGIC); |
| ASSERT(current_thread->state == THREAD_RUNNING); |
| #endif |
| |
| timer_initialize(&timer); |
| |
| enter_critical_section(); |
| timer_set_oneshot(&timer, delay, thread_sleep_handler, (void *)current_thread); |
| current_thread->state = THREAD_SLEEPING; |
| thread_resched(); |
| exit_critical_section(); |
| } |
| |
| /** |
| * @brief Initialize threading system |
| * |
| * This function is called once, from kmain() |
| */ |
| void thread_init_early(void) |
| { |
| int i; |
| |
| /* initialize the run queues */ |
| for (i=0; i < NUM_PRIORITIES; i++) |
| list_initialize(&run_queue[i]); |
| |
| /* initialize the thread list */ |
| list_initialize(&thread_list); |
| |
| /* create a thread to cover the current running state */ |
| thread_t *t = &bootstrap_thread; |
| init_thread_struct(t, "bootstrap"); |
| |
| /* half construct this thread, since we're already running */ |
| t->priority = HIGHEST_PRIORITY; |
| t->state = THREAD_RUNNING; |
| t->saved_critical_section_count = 1; |
| list_add_head(&thread_list, &t->thread_list_node); |
| current_thread = t; |
| } |
| |
| /** |
| * @brief Complete thread initialization |
| * |
| * This function is called once at boot time |
| */ |
| void thread_init(void) |
| { |
| #if PLATFORM_HAS_DYNAMIC_TIMER |
| timer_initialize(&preempt_timer); |
| #endif |
| } |
| |
| /** |
| * @brief Change name of current thread |
| */ |
| void thread_set_name(const char *name) |
| { |
| strlcpy(current_thread->name, name, sizeof(current_thread->name)); |
| } |
| |
| /** |
| * @brief Change priority of current thread |
| * |
| * See thread_create() for a discussion of priority values. |
| */ |
| void thread_set_priority(int priority) |
| { |
| if (priority < LOWEST_PRIORITY) |
| priority = LOWEST_PRIORITY; |
| if (priority > HIGHEST_PRIORITY) |
| priority = HIGHEST_PRIORITY; |
| current_thread->priority = priority; |
| } |
| |
| /** |
| * @brief Become an idle thread |
| * |
| * This function marks the current thread as the idle thread -- the one which |
| * executes when there is nothing else to do. This function does not return. |
| * This function is called once at boot time. |
| */ |
| void thread_become_idle(void) |
| { |
| thread_set_name("idle"); |
| thread_set_priority(IDLE_PRIORITY); |
| idle_thread = current_thread; |
| idle_thread_routine(); |
| } |
| |
| /** |
| * @brief Dump debugging info about the specified thread. |
| */ |
| void dump_thread(thread_t *t) |
| { |
| dprintf(INFO, "dump_thread: t %p (%s)\n", t, t->name); |
| dprintf(INFO, "\tstate %d, priority %d, remaining quantum %d, critical section %d\n", t->state, t->priority, t->remaining_quantum, t->saved_critical_section_count); |
| dprintf(INFO, "\tstack %p, stack_size %zd\n", t->stack, t->stack_size); |
| dprintf(INFO, "\tentry %p, arg %p\n", t->entry, t->arg); |
| dprintf(INFO, "\twait queue %p, wait queue ret %d\n", t->blocking_wait_queue, t->wait_queue_block_ret); |
| dprintf(INFO, "\ttls:"); |
| int i; |
| for (i=0; i < MAX_TLS_ENTRY; i++) { |
| dprintf(INFO, " 0x%x", t->tls[i]); |
| } |
| dprintf(INFO, "\n"); |
| } |
| |
| /** |
| * @brief Dump debugging info about all threads |
| */ |
| void dump_all_threads(void) |
| { |
| thread_t *t; |
| |
| enter_critical_section(); |
| list_for_every_entry(&thread_list, t, thread_t, thread_list_node) { |
| dump_thread(t); |
| } |
| exit_critical_section(); |
| } |
| |
| /** @} */ |
| |
| |
| /** |
| * @defgroup wait Wait Queue |
| * @{ |
| */ |
| |
| /** |
| * @brief Initialize a wait queue |
| */ |
| void wait_queue_init(wait_queue_t *wait) |
| { |
| wait->magic = WAIT_QUEUE_MAGIC; |
| list_initialize(&wait->list); |
| wait->count = 0; |
| } |
| |
| static enum handler_return wait_queue_timeout_handler(timer_t *timer, time_t now, void *arg) |
| { |
| thread_t *thread = (thread_t *)arg; |
| |
| #if THREAD_CHECKS |
| ASSERT(thread->magic == THREAD_MAGIC); |
| #endif |
| |
| if (thread_unblock_from_wait_queue(thread, false, ERR_TIMED_OUT) >= NO_ERROR) |
| return INT_RESCHEDULE; |
| |
| return INT_NO_RESCHEDULE; |
| } |
| |
| /** |
| * @brief Block until a wait queue is notified. |
| * |
| * This function puts the current thread at the end of a wait |
| * queue and then blocks until some other thread wakes the queue |
| * up again. |
| * |
| * @param wait The wait queue to enter |
| * @param timeout The maximum time, in ms, to wait |
| * |
| * If the timeout is zero, this function returns immediately with |
| * ERR_TIMED_OUT. If the timeout is INFINITE_TIME, this function |
| * waits indefinitely. Otherwise, this function returns with |
| * ERR_TIMED_OUT at the end of the timeout period. |
| * |
| * @return ERR_TIMED_OUT on timeout, else returns the return |
| * value specified when the queue was woken by wait_queue_wake_one(). |
| */ |
| status_t wait_queue_block(wait_queue_t *wait, time_t timeout) |
| { |
| timer_t timer; |
| |
| #if THREAD_CHECKS |
| ASSERT(wait->magic == WAIT_QUEUE_MAGIC); |
| ASSERT(current_thread->state == THREAD_RUNNING); |
| ASSERT(in_critical_section()); |
| #endif |
| |
| if (timeout == 0) |
| return ERR_TIMED_OUT; |
| |
| list_add_tail(&wait->list, ¤t_thread->queue_node); |
| wait->count++; |
| current_thread->state = THREAD_BLOCKED; |
| current_thread->blocking_wait_queue = wait; |
| current_thread->wait_queue_block_ret = NO_ERROR; |
| |
| /* if the timeout is nonzero or noninfinite, set a callback to yank us out of the queue */ |
| if (timeout != INFINITE_TIME) { |
| timer_initialize(&timer); |
| timer_set_oneshot(&timer, timeout, wait_queue_timeout_handler, (void *)current_thread); |
| } |
| |
| thread_block(); |
| |
| /* we don't really know if the timer fired or not, so it's better safe to try to cancel it */ |
| if (timeout != INFINITE_TIME) { |
| timer_cancel(&timer); |
| } |
| |
| return current_thread->wait_queue_block_ret; |
| } |
| |
| /** |
| * @brief Wake up one thread sleeping on a wait queue |
| * |
| * This function removes one thread (if any) from the head of the wait queue and |
| * makes it executable. The new thread will be placed at the head of the |
| * run queue. |
| * |
| * @param wait The wait queue to wake |
| * @param reschedule If true, the newly-woken thread will run immediately. |
| * @param wait_queue_error The return value which the new thread will receive |
| * from wait_queue_block(). |
| * |
| * @return The number of threads woken (zero or one) |
| */ |
| int wait_queue_wake_one(wait_queue_t *wait, bool reschedule, status_t wait_queue_error) |
| { |
| thread_t *t; |
| int ret = 0; |
| |
| #if THREAD_CHECKS |
| ASSERT(wait->magic == WAIT_QUEUE_MAGIC); |
| ASSERT(in_critical_section()); |
| #endif |
| |
| t = list_remove_head_type(&wait->list, thread_t, queue_node); |
| if (t) { |
| wait->count--; |
| #if THREAD_CHECKS |
| ASSERT(t->state == THREAD_BLOCKED); |
| #endif |
| t->state = THREAD_READY; |
| t->wait_queue_block_ret = wait_queue_error; |
| t->blocking_wait_queue = NULL; |
| |
| /* if we're instructed to reschedule, stick the current thread on the head |
| * of the run queue first, so that the newly awakened thread gets a chance to run |
| * before the current one, but the current one doesn't get unnecessarilly punished. |
| */ |
| if (reschedule) { |
| current_thread->state = THREAD_READY; |
| insert_in_run_queue_head(current_thread); |
| } |
| insert_in_run_queue_head(t); |
| if (reschedule) |
| thread_resched(); |
| ret = 1; |
| } |
| |
| return ret; |
| } |
| |
| |
| /** |
| * @brief Wake all threads sleeping on a wait queue |
| * |
| * This function removes all threads (if any) from the wait queue and |
| * makes them executable. The new threads will be placed at the head of the |
| * run queue. |
| * |
| * @param wait The wait queue to wake |
| * @param reschedule If true, the newly-woken threads will run immediately. |
| * @param wait_queue_error The return value which the new thread will receive |
| * from wait_queue_block(). |
| * |
| * @return The number of threads woken (zero or one) |
| */ |
| int wait_queue_wake_all(wait_queue_t *wait, bool reschedule, status_t wait_queue_error) |
| { |
| thread_t *t; |
| int ret = 0; |
| |
| #if THREAD_CHECKS |
| ASSERT(wait->magic == WAIT_QUEUE_MAGIC); |
| ASSERT(in_critical_section()); |
| #endif |
| |
| if (reschedule && wait->count > 0) { |
| /* if we're instructed to reschedule, stick the current thread on the head |
| * of the run queue first, so that the newly awakened threads get a chance to run |
| * before the current one, but the current one doesn't get unnecessarilly punished. |
| */ |
| current_thread->state = THREAD_READY; |
| insert_in_run_queue_head(current_thread); |
| } |
| |
| /* pop all the threads off the wait queue into the run queue */ |
| while ((t = list_remove_head_type(&wait->list, thread_t, queue_node))) { |
| wait->count--; |
| #if THREAD_CHECKS |
| ASSERT(t->state == THREAD_BLOCKED); |
| #endif |
| t->state = THREAD_READY; |
| t->wait_queue_block_ret = wait_queue_error; |
| t->blocking_wait_queue = NULL; |
| |
| insert_in_run_queue_head(t); |
| ret++; |
| } |
| |
| #if THREAD_CHECKS |
| ASSERT(wait->count == 0); |
| #endif |
| |
| if (reschedule && ret > 0) |
| thread_resched(); |
| |
| return ret; |
| } |
| |
| /** |
| * @brief Free all resources allocated in wait_queue_init() |
| * |
| * If any threads were waiting on this queue, they are all woken. |
| */ |
| void wait_queue_destroy(wait_queue_t *wait, bool reschedule) |
| { |
| #if THREAD_CHECKS |
| ASSERT(wait->magic == WAIT_QUEUE_MAGIC); |
| ASSERT(in_critical_section()); |
| #endif |
| wait_queue_wake_all(wait, reschedule, ERR_OBJECT_DESTROYED); |
| wait->magic = 0; |
| } |
| |
| /** |
| * @brief Wake a specific thread in a wait queue |
| * |
| * This function extracts a specific thread from a wait queue, wakes it, and |
| * puts it at the head of the run queue. |
| * |
| * @param t The thread to wake |
| * @param reschedule If true, the newly-woken threads will run immediately. |
| * @param wait_queue_error The return value which the new thread will receive |
| * from wait_queue_block(). |
| * |
| * @return ERR_NOT_BLOCKED if thread was not in any wait queue. |
| */ |
| status_t thread_unblock_from_wait_queue(thread_t *t, bool reschedule, status_t wait_queue_error) |
| { |
| enter_critical_section(); |
| |
| #if THREAD_CHECKS |
| ASSERT(t->magic == THREAD_MAGIC); |
| #endif |
| |
| if (t->state != THREAD_BLOCKED) |
| return ERR_NOT_BLOCKED; |
| |
| #if THREAD_CHECKS |
| ASSERT(t->blocking_wait_queue != NULL); |
| ASSERT(t->blocking_wait_queue->magic == WAIT_QUEUE_MAGIC); |
| ASSERT(list_in_list(&t->queue_node)); |
| #endif |
| |
| list_delete(&t->queue_node); |
| t->blocking_wait_queue->count--; |
| t->blocking_wait_queue = NULL; |
| t->state = THREAD_READY; |
| t->wait_queue_block_ret = wait_queue_error; |
| insert_in_run_queue_head(t); |
| |
| if (reschedule) |
| thread_resched(); |
| |
| exit_critical_section(); |
| |
| return NO_ERROR; |
| } |
| |
| |