int task_activate(FAR _TCB *tcb)
{
irqstate_t flags = irqsave();
#ifdef CONFIG_SCHED_INSTRUMENTATION
/* Check if this is really a re-start */
if (tcb->task_state != TSTATE_TASK_INACTIVE)
{
/* Inform the instrumentation layer that the task
* has stopped
*/
sched_note_stop(tcb);
}
/* Inform the instrumentation layer that the task
* has started
*/
sched_note_start(tcb);
#endif
up_unblock_task(tcb);
irqrestore(flags);
return OK;
}
static void sig_timeout(int argc, uint32_t itcb)
{
/* On many small machines, pointers are encoded and cannot be simply cast
* from uint32_t to struct tcb_s*. The following union works around this
* (see wdogparm_t). This odd logic could be conditioned on
* CONFIG_CAN_CAST_POINTERS, but it is not too bad in any case.
*/
union
{
FAR struct tcb_s *wtcb;
uint32_t itcb;
} u;
u.itcb = itcb;
ASSERT(u.wtcb);
/* There may be a race condition -- make sure the task is
* still waiting for a signal
*/
if (u.wtcb->task_state == TSTATE_WAIT_SIG)
{
u.wtcb->sigunbinfo.si_signo = SIG_WAIT_TIMEOUT;
u.wtcb->sigunbinfo.si_code = SI_TIMER;
u.wtcb->sigunbinfo.si_value.sival_int = 0;
#ifdef CONFIG_SCHED_HAVE_PARENT
u.wtcb->sigunbinfo.si_pid = 0; /* Not applicable */
u.wtcb->sigunbinfo.si_status = OK;
#endif
up_unblock_task(u.wtcb);
}
}
ssize_t mq_doreceive(mqd_t mqdes, mqmsg_t *mqmsg, void *ubuffer, int *prio)
{
FAR struct tcb_s *btcb;
irqstate_t saved_state;
FAR msgq_t *msgq;
ssize_t rcvmsglen;
/* Get the length of the message (also the return value) */
rcvmsglen = mqmsg->msglen;
/* Copy the message into the caller's buffer */
memcpy(ubuffer, (const void*)mqmsg->mail, rcvmsglen);
/* Copy the message priority as well (if a buffer is provided) */
if (prio)
{
*prio = mqmsg->priority;
}
/* We are done with the message. Deallocate it now. */
mq_msgfree(mqmsg);
/* Check if any tasks are waiting for the MQ not full event. */
msgq = mqdes->msgq;
if (msgq->nwaitnotfull > 0)
{
/* Find the highest priority task that is waiting for
* this queue to be not-full in g_waitingformqnotfull list.
* This must be performed in a critical section because
* messages can be sent from interrupt handlers.
*/
saved_state = irqsave();
for (btcb = (FAR struct tcb_s*)g_waitingformqnotfull.head;
btcb && btcb->msgwaitq != msgq;
btcb = btcb->flink);
/* If one was found, unblock it. NOTE: There is a race
* condition here: the queue might be full again by the
* time the task is unblocked
*/
ASSERT(btcb);
btcb->msgwaitq = NULL;
msgq->nwaitnotfull--;
up_unblock_task(btcb);
irqrestore(saved_state);
}
/* Return the length of the message transferred to the user buffer */
return rcvmsglen;
}
static inline void pg_fillcomplete(void)
{
/* Call up_unblocktask(g_pftcb) to make the task that just
* received the fill ready-to-run.
*/
pglldbg("Restarting TCB: %p\n", g_pftcb);
up_unblock_task(g_pftcb);
}
void mq_waitirq(FAR struct tcb_s *wtcb, int errcode)
{
FAR struct mqueue_inode_s *msgq;
irqstate_t saved_state;
/* Disable interrupts. This is necessary because an interrupt handler may
* attempt to send a message while we are doing this.
*/
saved_state = irqsave();
/* It is possible that an interrupt/context switch beat us to the punch and
* already changed the task's state. NOTE: The operations within the if
* are safe because interrupts are always disabled with the msgwaitq,
* nwaitnotempty, and nwaitnotfull fields are modified.
*/
if (wtcb->task_state == TSTATE_WAIT_MQNOTEMPTY ||
wtcb->task_state == TSTATE_WAIT_MQNOTFULL)
{
/* Get the message queue associated with the waiter from the TCB */
msgq = wtcb->msgwaitq;
DEBUGASSERT(msgq);
wtcb->msgwaitq = NULL;
/* Decrement the count of waiters and cancel the wait */
if (wtcb->task_state == TSTATE_WAIT_MQNOTEMPTY)
{
DEBUGASSERT(msgq->nwaitnotempty > 0);
msgq->nwaitnotempty--;
}
else
{
DEBUGASSERT(msgq->nwaitnotfull > 0);
msgq->nwaitnotfull--;
}
/* Mark the errno value for the thread. */
wtcb->pterrno = errcode;
/* Restart the task. */
up_unblock_task(wtcb);
}
/* Interrupts may now be enabled. */
irqrestore(saved_state);
}
int pg_worker(int argc, char *argv[])
{
irqstate_t flags;
/* Loop forever -- Notice that interrupts will be disable at all times that
* this thread runs. That is so that we con't lose signals or have
* asynchronous page faults.
*
* All interrupt logic as well as all page fill worker thread logic must
* be locked in memory. Therefore, keeping interrupts disabled here
* should prevent any concurrent page faults. Any page faults or page
* fill completions should occur while this thread sleeps.
*/
pglldbg("Started\n");
flags = irqsave();
for (;;)
{
/* Wait awhile. We will wait here until either the configurable timeout
* elapses or until we are awakened by a signal (which terminates the
* usleep with an EINTR error). Note that interrupts will be re-enabled
* while this task sleeps.
*
* The timeout is a failsafe that will handle any cases where a single
* is lost (that would really be a bug and shouldn't happen!) and also
* supports timeouts for case of non-blocking, asynchronous fills.
*/
usleep(CONFIG_PAGING_WORKPERIOD);
/* The page fill worker thread will be awakened on one of three conditions:
*
* - When signaled by pg_miss(), the page fill worker thread will be awakenend,
* - if CONFIG_PAGING_BLOCKINGFILL is not defined, from pg_callback()
* after completing a page fill, or
* - On a configurable timeout expires with no activity.
*
* Interrupts are still disabled.
*/
#ifndef CONFIG_PAGING_BLOCKINGFILL
/* For the non-blocking up_fillpage(), the page fill worker thread will detect
* that the page fill is complete when it is awakened with g_pftcb non-NULL
* and fill completion status from pg_callback.
*/
if (g_pftcb != NULL)
{
/* If it is a real page fill completion event, then the result of the page
* fill will be in g_fillresult and will not be equal to -EBUSY.
*/
if (g_fillresult != -EBUSY)
{
/* Any value other than OK, brings the system down */
ASSERT(g_fillresult == OK);
/* Handle the successful page fill complete event by restarting the
* task that was blocked waiting for this page fill.
*/
pglldbg("Restarting TCB: %p\n", g_pftcb);
up_unblock_task(g_pftcb);;
/* Yes .. Start the next asynchronous fill. Check the return
* value to see a fill was actually started (false means that
* no fill was started).
*/
pgllvdbg("Calling pg_startfill\n");
if (!pg_startfill())
{
/* No fill was started. This can mean only that all queued
* page fill actions have and been completed and there is
* nothing more to do.
*/
pgllvdbg("Call pg_alldone()\n");
pg_alldone();
}
}
/* If a configurable timeout period expires with no page fill completion
* event, then declare a failure.
*/
#ifdef CONFIG_PAGING_TIMEOUT_TICKS
else
{
lldbg("Timeout!\n");
ASSERT(clock_systimer() - g_starttime < CONFIG_PAGING_TIMEOUT_TICKS);
}
#endif
}
/* Otherwise, this might be a page fill initiation event. When
* awakened from pg_miss(), no fill will be in progress and
* g_pftcb will be NULL.
*/
else
{
/* Are there tasks blocked and waiting for a fill? If so,
* pg_startfill() will start the asynchronous fill (and set
* g_pftcb).
*/
pgllvdbg("Calling pg_startfill\n");
(void)pg_startfill();
}
#else
/* Are there tasks blocked and waiting for a fill? Loop until all
* pending fills have been processed.
*/
for (;;)
{
/* Yes .. Start the fill and block until the fill completes.
* Check the return value to see a fill was actually performed.
* (false means that no fill was perforemd).
*/
pgllvdbg("Calling pg_startfill\n");
if (!pg_startfill())
{
/* Break out of the loop -- there is nothing more to do */
break;
}
/* Handle the page fill complete event by restarting the
* task that was blocked waiting for this page fill. In the
* non-blocking fill case, the page fill worker thread will
* know that the page fill is complete when pg_startfill()
* returns true.
*/
pgllvdbg("Restarting TCB: %p\n", g_pftcb);
up_unblock_task(g_pftcb);;
}
/* All queued fills have been processed */
pgllvdbg("Call pg_alldone()\n");
pg_alldone();
#endif
}
return OK; /* To keep some compilers happy */
}
static inline bool pg_dequeue(void)
{
/* Loop until either (1) the TCB of a task that requires a fill is found, OR
* (2) the g_watingforfill list becomes empty.
*/
do
{
/* Remove the TCB from the head of the list (if any) */
g_pftcb = (FAR struct tcb_s *)dq_remfirst((dq_queue_t*)&g_waitingforfill);
pgllvdbg("g_pftcb: %p\n", g_pftcb);
if (g_pftcb != NULL)
{
/* Call the architecture-specific function up_checkmapping() to see if
* the page fill still needs to be performed. In certain conditions,
* the page fault may occur on several threads for the same page and
* be queues multiple times. In this corner case, the blocked task will
* simply be restarted.
*/
if (!up_checkmapping(g_pftcb))
{
/* This page needs to be filled. pg_miss bumps up
* the priority of the page fill worker thread as each
* TCB is added to the g_waitingforfill list. So we
* may need to also drop the priority of the worker
* thread as the next TCB comes off of the list.
*
* If wtcb->sched_priority > CONFIG_PAGING_DEFPRIO,
* then the page fill worker thread is executing at
* an elevated priority that may be reduced.
*
* If wtcb->sched_priority > g_pftcb->sched_priority
* then the page fill worker thread is executing at
* a higher priority than is appropriate for this
* fill (this priority can get re-boosted by pg_miss()
* if a new higher priority fill is required).
*/
FAR struct tcb_s *wtcb = (FAR struct tcb_s *)g_readytorun.head;
if (wtcb->sched_priority > CONFIG_PAGING_DEFPRIO &&
wtcb->sched_priority > g_pftcb->sched_priority)
{
/* Don't reduce the priority of the page fill
* worker thread lower than the configured
* minimum.
*/
int priority = g_pftcb->sched_priority;
if (priority < CONFIG_PAGING_DEFPRIO)
{
priority = CONFIG_PAGING_DEFPRIO;
}
/* Reduce the priority of the page fill worker thread */
pgllvdbg("New worker priority. %d->%d\n",
wtcb->sched_priority, priority);
sched_setpriority(wtcb, priority);
}
/* Return with g_pftcb holding the pointer to
* the TCB associated with task that requires the page fill.
*/
return true;
}
/* The page need by this task has already been mapped into the
* virtual address space -- just restart it.
*/
pglldbg("Restarting TCB: %p\n", g_pftcb);
up_unblock_task(g_pftcb);
}
}
while (g_pftcb != NULL);
return false;
}
int mq_dosend(mqd_t mqdes, FAR struct mqueue_msg_s *mqmsg, FAR const char *msg,
size_t msglen, int prio)
{
FAR struct tcb_s *btcb;
FAR struct mqueue_inode_s *msgq;
FAR struct mqueue_msg_s *next;
FAR struct mqueue_msg_s *prev;
irqstate_t saved_state;
/* Get a pointer to the message queue */
sched_lock();
msgq = mqdes->msgq;
/* Construct the message header info */
mqmsg->priority = prio;
mqmsg->msglen = msglen;
/* Copy the message data into the message */
memcpy((FAR void *)mqmsg->mail, (FAR const void *)msg, msglen);
/* Insert the new message in the message queue */
saved_state = irqsave();
/* Search the message list to find the location to insert the new
* message. Each is list is maintained in ascending priority order.
*/
for (prev = NULL, next = (FAR struct mqueue_msg_s *)msgq->msglist.head;
next && prio <= next->priority;
prev = next, next = next->next);
/* Add the message at the right place */
if (prev)
{
sq_addafter((FAR sq_entry_t *)prev, (FAR sq_entry_t *)mqmsg,
&msgq->msglist);
}
else
{
sq_addfirst((FAR sq_entry_t *)mqmsg, &msgq->msglist);
}
/* Increment the count of messages in the queue */
msgq->nmsgs++;
irqrestore(saved_state);
/* Check if we need to notify any tasks that are attached to the
* message queue
*/
#ifndef CONFIG_DISABLE_SIGNALS
if (msgq->ntmqdes)
{
struct sigevent event;
pid_t pid;
/* Remove the message notification data from the message queue. */
memcpy(&event, &msgq->ntevent, sizeof(struct sigevent));
pid = msgq->ntpid;
/* Detach the notification */
memset(&msgq->ntevent, 0, sizeof(struct sigevent));
msgq->ntpid = INVALID_PROCESS_ID;
msgq->ntmqdes = NULL;
/* Notification the client via signal? */
if (event.sigev_notify == SIGEV_SIGNAL)
{
/* Yes... Queue the signal -- What if this returns an error? */
#ifdef CONFIG_CAN_PASS_STRUCTS
DEBUGVERIFY(sig_mqnotempty(pid, event.sigev_signo,
event.sigev_value));
#else
DEBUGVERIFY(sig_mqnotempty(pid, event.sigev_signo,
event.sigev_value.sival_ptr));
#endif
}
#ifdef CONFIG_SIG_EVTHREAD
/* Notify the client via a function call */
else if (event.sigev_notify == SIGEV_THREAD)
{
DEBUGVERIFY(sig_notification(pid, &event));
}
#endif
}
#endif
/* Check if any tasks are waiting for the MQ not empty event. */
saved_state = irqsave();
if (msgq->nwaitnotempty > 0)
{
/* Find the highest priority task that is waiting for
* this queue to be non-empty in g_waitingformqnotempty
* list. sched_lock() should give us sufficent protection since
* interrupts should never cause a change in this list
*/
for (btcb = (FAR struct tcb_s *)g_waitingformqnotempty.head;
btcb && btcb->msgwaitq != msgq;
btcb = btcb->flink);
/* If one was found, unblock it */
ASSERT(btcb);
btcb->msgwaitq = NULL;
msgq->nwaitnotempty--;
up_unblock_task(btcb);
}
irqrestore(saved_state);
sched_unlock();
return OK;
}
void mq_waitirq(FAR struct tcb_s *wtcb, int errcode)
{
FAR msgq_t *msgq;
irqstate_t saved_state;
/* Disable interrupts. This is necessary because an interrupt handler may
* attempt to send a message while we are doing this.
*/
saved_state = irqsave();
/* It is possible that an interrupt/context switch beat us to the punch and
* already changed the task's state. NOTE: The operations within the if
* are safe because interrupts are always disabled with the msgwaitq,
* nwaitnotempty, and nwaitnotfull fields are modified.
*/
if (wtcb->task_state == TSTATE_WAIT_MQNOTEMPTY ||
wtcb->task_state == TSTATE_WAIT_MQNOTFULL)
{
/* Get the message queue associated with the waiter from the TCB */
msgq = wtcb->msgwaitq;
#ifdef CONFIG_DEBUG
if (!msgq)
{
/* In these states there must always be an associated message queue */
PANIC((uint32_t)OSERR_MQNOWAITER);
}
#endif
wtcb->msgwaitq = NULL;
/* Decrement the count of waiters and cancel the wait */
if (wtcb->task_state == TSTATE_WAIT_MQNOTEMPTY)
{
#ifdef CONFIG_DEBUG
if (msgq->nwaitnotempty <= 0)
{
/* This state, there should be a positive, non-zero waiter
* count.
*/
PANIC((uint32_t)OSERR_MQNONEMPTYCOUNT);
}
#endif
msgq->nwaitnotempty--;
}
else
{
#ifdef CONFIG_DEBUG
if (msgq->nwaitnotfull <= 0)
{
/* This state, there should be a positive, non-zero waiter
* count.
*/
PANIC((uint32_t)OSERR_MQNOTFULLCOUNT);
}
#endif
msgq->nwaitnotfull--;
}
/* Mark the errno value for the thread. */
wtcb->pterrno = errcode;
/* Restart the task. */
up_unblock_task(wtcb);
}
/* Interrupts may now be enabled. */
irqrestore(saved_state);
}
int sem_post(FAR sem_t *sem)
{
FAR _TCB *stcb = NULL;
int ret = ERROR;
irqstate_t saved_state;
/* Make sure we were supplied with a valid semaphore. */
if (sem)
{
/* The following operations must be performed with interrupts
* disabled because sem_post() may be called from an interrupt
* handler.
*/
saved_state = irqsave();
/* Perform the semaphore unlock operation. */
ASSERT(sem->semcount < SEM_VALUE_MAX);
sem_releaseholder(sem);
sem->semcount++;
/* If the result of of semaphore unlock is non-positive, then
* there must be some task waiting for the semaphore.
*/
#ifdef CONFIG_PRIORITY_INHERITANCE
/* Don't let it run until we complete the priority restoration
* steps.
*/
sched_lock();
#endif
if (sem->semcount <= 0)
{
/* Check if there are any tasks in the waiting for semaphore
* task list that are waiting for this semaphore. This is a
* prioritized list so the first one we encounter is the one
* that we want.
*/
for (stcb = (FAR _TCB*)g_waitingforsemaphore.head;
(stcb && stcb->waitsem != sem);
stcb = stcb->flink);
if (stcb)
{
/* It is, let the task take the semaphore */
stcb->waitsem = NULL;
/* Restart the waiting task. */
up_unblock_task(stcb);
}
}
/* Check if we need to drop the priority of any threads holding
* this semaphore. The priority could have been boosted while they
* held the semaphore.
*/
#ifdef CONFIG_PRIORITY_INHERITANCE
sem_restorebaseprio(stcb, sem);
sched_unlock();
#endif
ret = OK;
/* Interrupts may now be enabled. */
irqrestore(saved_state);
}
return ret;
}
int sig_received(FAR _TCB *stcb, siginfo_t *info)
{
irqstate_t saved_state;
int ret = ERROR;
sdbg("TCB=0x%08x signo=%d code=%d value=%d mask=%08x\n",
stcb, info->si_signo, info->si_code,
info->si_value.sival_int, stcb->sigprocmask);
if (stcb && info)
{
ret = OK;
/****************** MASKED SIGNAL HANDLING ******************/
/* Check if the signal is masked -- if it is, it will be added to the
* list of pending signals.
*/
if (sigismember(&stcb->sigprocmask, info->si_signo))
{
/* Check if the task is waiting for this pending signal. If so,
* then unblock it. This must be performed in a critical section
* because signals can be queued from the interrupt level.
*/
saved_state = irqsave();
if (stcb->task_state == TSTATE_WAIT_SIG &&
sigismember(&stcb->sigwaitmask, info->si_signo))
{
memcpy(&stcb->sigunbinfo, info, sizeof(siginfo_t));
stcb->sigwaitmask = NULL_SIGNAL_SET;
up_unblock_task(stcb);
irqrestore(saved_state);
}
/* Its not one we are waiting for... Add it to the list of pending
* signals.
*/
else
{
irqrestore(saved_state);
if (!sig_addpendingsignal(stcb, info))
{
PANIC(OSERR_FAILEDTOADDSIGNAL);
}
}
}
/****************** UNMASKED SIGNAL HANDLING ******************/
else
{
/* Queue any sigaction's requested by this task. */
ret = sig_queueaction(stcb, info);
/* Then schedule execution of the signal handling action on
* the recipients thread.
*/
up_schedule_sigaction(stcb, sig_deliver);
/* Check if the task is waiting for an unmasked signal. If so,
* then unblock it. This must be performed in a critical section
* because signals can be queued from the interrupt level.
*/
saved_state = irqsave();
if (stcb->task_state == TSTATE_WAIT_SIG)
{
memcpy(&stcb->sigunbinfo, info, sizeof(siginfo_t));
stcb->sigwaitmask = NULL_SIGNAL_SET;
up_unblock_task(stcb);
}
irqrestore(saved_state);
/* If the task neither was waiting for the signal nor had a signal
* handler attached to the signal, then the default action is
* simply to ignore the signal
*/
/****************** OTHER SIGNAL HANDLING ******************/
/* If the task is blocked waiting for a semaphore, then that
* task must be unblocked when a signal is received.
*/
if (stcb->task_state == TSTATE_WAIT_SEM)
{
sem_waitirq(stcb);
}
/* If the task is blocked waiting on a message queue, then that
* task must be unblocked when a signal is received.
*/
#ifndef CONFIG_DISABLE_MQUEUE
if (stcb->task_state == TSTATE_WAIT_MQNOTEMPTY ||
stcb->task_state == TSTATE_WAIT_MQNOTFULL)
{
mq_waitirq(stcb);
}
#endif
}
}
return ret;
}
int sig_tcbdispatch(FAR struct tcb_s *stcb, siginfo_t *info)
{
irqstate_t saved_state;
int ret = OK;
sdbg("TCB=0x%08x signo=%d code=%d value=%d mask=%08x\n",
stcb, info->si_signo, info->si_code,
info->si_value.sival_int, stcb->sigprocmask);
DEBUGASSERT(stcb && info);
/************************* MASKED SIGNAL HANDLING ************************/
/* Check if the signal is masked -- if it is, it will be added to the list
* of pending signals.
*/
if (sigismember(&stcb->sigprocmask, info->si_signo))
{
/* Check if the task is waiting for this pending signal. If so, then unblock it.
* This must be performed in a critical section because signals can be queued
* from the interrupt level.
*/
saved_state = irqsave();
if (stcb->task_state == TSTATE_WAIT_SIG &&
sigismember(&stcb->sigwaitmask, info->si_signo))
{
memcpy(&stcb->sigunbinfo, info, sizeof(siginfo_t));
stcb->sigwaitmask = NULL_SIGNAL_SET;
up_unblock_task(stcb);
irqrestore(saved_state);
}
/* Its not one we are waiting for... Add it to the list of pending
* signals.
*/
else
{
irqrestore(saved_state);
FAR sigpendq_t *sigpend = sig_addpendingsignal(stcb, info);
ASSERT(sigpend);
#ifdef __clang_analyzer__
/* clang analyzer does not understand memory ownership transfer */
free(sigpend);
#endif
}
}
/************************ UNMASKED SIGNAL HANDLING ***********************/
else
{
/* Queue any sigaction's requested by this task. */
ret = sig_queueaction(stcb, info);
/* Then schedule execution of the signal handling action on the
* recipient's thread.
*/
up_schedule_sigaction(stcb, sig_deliver);
/* Check if the task is waiting for an unmasked signal. If so, then
* unblock it. This must be performed in a critical section because
* signals can be queued from the interrupt level.
*/
saved_state = irqsave();
if (stcb->task_state == TSTATE_WAIT_SIG)
{
memcpy(&stcb->sigunbinfo, info, sizeof(siginfo_t));
stcb->sigwaitmask = NULL_SIGNAL_SET;
up_unblock_task(stcb);
}
irqrestore(saved_state);
/* If the task neither was waiting for the signal nor had a signal
* handler attached to the signal, then the default action is
* simply to ignore the signal
*/
/*********************** OTHER SIGNAL HANDLING ***********************/
/* If the task is blocked waiting for a semaphore, then that task must
* be unblocked when a signal is received.
*/
if (stcb->task_state == TSTATE_WAIT_SEM)
{
sem_waitirq(stcb, EINTR);
}
/* If the task is blocked waiting on a message queue, then that task
* must be unblocked when a signal is received.
*/
#ifndef CONFIG_DISABLE_MQUEUE
if (stcb->task_state == TSTATE_WAIT_MQNOTEMPTY ||
stcb->task_state == TSTATE_WAIT_MQNOTFULL)
{
mq_waitirq(stcb, EINTR);
}
#endif
}
return ret;
}
