int set_timer(uint64_t deadline)
{
task_t* curr_task;
uint32_t core_id;
uint8_t flags;
int ret = -EINVAL;
flags = irq_nested_disable();
curr_task = per_core(current_task);
core_id = CORE_ID;
if (curr_task->status == TASK_RUNNING) {
// blocks task and removes from ready queue
block_task(curr_task->id);
curr_task->flags |= TASK_TIMER;
curr_task->timeout = deadline;
timer_queue_push(core_id, curr_task);
ret = 0;
} else {
LOG_INFO("Task is already blocked. No timer will be set!\n");
}
irq_nested_enable(flags);
return ret;
}
int block_task(tid_t id)
{
task_t* task;
uint32_t core_id;
int ret = -EINVAL;
uint8_t flags;
flags = irq_nested_disable();
task = &task_table[id];
core_id = task->last_core;
if (task->status == TASK_RUNNING) {
LOG_DEBUG("block task %d on core %d\n", id, core_id);
task->status = TASK_BLOCKED;
spinlock_irqsave_lock(&readyqueues[core_id].lock);
// remove task from ready queue
readyqueues_remove(core_id, task);
// reduce the number of ready tasks
readyqueues[core_id].nr_tasks--;
LOG_DEBUG("update nr_tasks on core %d to %d\n", core_id, readyqueues[core_id].nr_tasks);
spinlock_irqsave_unlock(&readyqueues[core_id].lock);
ret = 0;
}
irq_nested_enable(flags);
return ret;
}
void NORETURN do_exit(int arg)
{
task_t* curr_task = per_core(current_task);
const uint32_t core_id = CORE_ID;
LOG_INFO("Terminate task: %u, return value %d\n", curr_task->id, arg);
uint8_t flags = irq_nested_disable();
// decrease the number of active tasks
spinlock_irqsave_lock(&readyqueues[core_id].lock);
readyqueues[core_id].nr_tasks--;
spinlock_irqsave_unlock(&readyqueues[core_id].lock);
// release the thread local storage
destroy_tls();
curr_task->status = TASK_FINISHED;
reschedule();
irq_nested_enable(flags);
LOG_ERROR("Kernel panic: scheduler found no valid task\n");
while(1) {
HALT;
}
}
void reschedule(void)
{
size_t** stack;
uint8_t flags;
flags = irq_nested_disable();
if ((stack = scheduler()))
switch_context(stack);
irq_nested_enable(flags);
}
/** @brief Block current task
*
* The current task's status will be changed to TASK_BLOCKED
*
* @return
* - 0 on success
* - -EINVAL (-22) on failure
*/
int block_current_task(void)
{
tid_t id;
uint32_t prio;
int ret = -EINVAL;
uint8_t flags;
flags = irq_nested_disable();
id = current_task->id;
prio = current_task->prio;
if (task_table[id].status == TASK_RUNNING) {
task_table[id].status = TASK_BLOCKED;
ret = 0;
spinlock_irqsave_lock(&readyqueues.lock);
// reduce the number of ready tasks
readyqueues.nr_tasks--;
// remove task from queue
if (task_table[id].prev)
task_table[id].prev->next = task_table[id].next;
if (task_table[id].next)
task_table[id].next->prev = task_table[id].prev;
if (readyqueues.queue[prio-1].first == task_table+id)
readyqueues.queue[prio-1].first = task_table[id].next;
if (readyqueues.queue[prio-1].last == task_table+id) {
readyqueues.queue[prio-1].last = task_table[id].prev;
if (!readyqueues.queue[prio-1].last)
readyqueues.queue[prio-1].last = readyqueues.queue[prio-1].first;
}
// No valid task in queue => update prio_bitmap
if (!readyqueues.queue[prio-1].first)
readyqueues.prio_bitmap &= ~(1 << prio);
spinlock_irqsave_unlock(&readyqueues.lock);
}
irq_nested_enable(flags);
return ret;
}
/** @brief Wakeup a blocked task
* @param id The task's tid_t structure
* @return
* - 0 on success
* - -EINVAL (-22) on failure
*/
int wakeup_task(tid_t id)
{
task_t* task;
uint32_t prio;
int ret = -EINVAL;
uint8_t flags;
flags = irq_nested_disable();
task = task_table + id;
prio = task->prio;
if (task->status == TASK_BLOCKED) {
task->status = TASK_READY;
ret = 0;
spinlock_irqsave_lock(&readyqueues.lock);
// increase the number of ready tasks
readyqueues.nr_tasks++;
// add task to the runqueue
if (!readyqueues.queue[prio-1].last) {
readyqueues.queue[prio-1].last = readyqueues.queue[prio-1].first = task;
task->next = task->prev = NULL;
readyqueues.prio_bitmap |= (1 << prio);
} else {
task->prev = readyqueues.queue[prio-1].last;
task->next = NULL;
readyqueues.queue[prio-1].last->next = task;
readyqueues.queue[prio-1].last = task;
}
spinlock_irqsave_unlock(&readyqueues.lock);
}
irq_nested_enable(flags);
return ret;
}
