You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
145 lines
5.1 KiB
145 lines
5.1 KiB
/**************************************************************************** |
|
* sched/sem_waitirq.c |
|
* |
|
* Copyright (C) 2007-2010 Gregory Nutt. All rights reserved. |
|
* Author: Gregory Nutt <gnutt@nuttx.org> |
|
* |
|
* Redistribution and use in source and binary forms, with or without |
|
* modification, are permitted provided that the following conditions |
|
* are met: |
|
* |
|
* 1. Redistributions of source code must retain the above copyright |
|
* notice, this list of conditions and the following disclaimer. |
|
* 2. Redistributions in binary form must reproduce the above copyright |
|
* notice, this list of conditions and the following disclaimer in |
|
* the documentation and/or other materials provided with the |
|
* distribution. |
|
* 3. Neither the name NuttX nor the names of its contributors may be |
|
* used to endorse or promote products derived from this software |
|
* without specific prior written permission. |
|
* |
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
|
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
|
* POSSIBILITY OF SUCH DAMAGE. |
|
* |
|
****************************************************************************/ |
|
|
|
/**************************************************************************** |
|
* Included Files |
|
****************************************************************************/ |
|
|
|
#include <nuttx/config.h> |
|
|
|
#include <sched.h> |
|
#include <errno.h> |
|
#include <nuttx/arch.h> |
|
|
|
#include "sem_internal.h" |
|
|
|
/**************************************************************************** |
|
* Definitions |
|
****************************************************************************/ |
|
|
|
/**************************************************************************** |
|
* Private Type Declarations |
|
****************************************************************************/ |
|
|
|
/**************************************************************************** |
|
* Global Variables |
|
****************************************************************************/ |
|
|
|
/**************************************************************************** |
|
* Private Variables |
|
****************************************************************************/ |
|
|
|
/**************************************************************************** |
|
* Private Functions |
|
****************************************************************************/ |
|
|
|
/**************************************************************************** |
|
* Public Functions |
|
****************************************************************************/ |
|
|
|
/**************************************************************************** |
|
* Name: sem_waitirq |
|
* |
|
* Description: |
|
* This function is called when a signal is received by a task that is |
|
* waiting on a semaphore. According to the POSIX spec, "...the calling |
|
* thread shall not return from the call to [sem_wait] until it either |
|
* locks the semaphore or the call is interrupted by a signal." |
|
* |
|
* Parameters: |
|
* wtcb - A pointer to the TCB of the task that is waiting on a |
|
* semphaphore, but has received a signal or timeout instead. |
|
* errcode - EINTR if the semaphore wait was awakened by a signal; |
|
* ETIMEDOUT if awakened by a timeout |
|
* |
|
* Return Value: |
|
* None |
|
* |
|
* Assumptions: |
|
* |
|
****************************************************************************/ |
|
|
|
void sem_waitirq(FAR _TCB *wtcb, int errcode) |
|
{ |
|
irqstate_t saved_state; |
|
|
|
/* Disable interrupts. This is necessary (unfortunately) because an |
|
* interrupt handler may attempt to post the semaphore 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. |
|
*/ |
|
|
|
if (wtcb->task_state == TSTATE_WAIT_SEM) |
|
{ |
|
sem_t *sem = wtcb->waitsem; |
|
DEBUGASSERT(sem != NULL && sem->semcount < 0); |
|
|
|
/* Restore the correct priority of all threads that hold references |
|
* to this semaphore. |
|
*/ |
|
|
|
sem_canceled(wtcb, sem); |
|
|
|
/* And increment the count on the semaphore. This releases the count |
|
* that was taken by sem_post(). This count decremented the semaphore |
|
* count to negative and caused the thread to be blocked in the first |
|
* place. |
|
*/ |
|
|
|
sem->semcount++; |
|
|
|
/* Indicate that the semaphore wait is over. */ |
|
|
|
wtcb->waitsem = NULL; |
|
|
|
/* 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); |
|
} |
|
|
|
|