score/src/corebarrierwait.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup RTEMSScoreBarrier
0007  *
0008  * @brief This source file contains the implementation of
0009  *   _CORE_barrier_Seize().
0010  */
0011
0012 /*
0013  *  COPYRIGHT (c) 1989-2006.
0014  *  On-Line Applications Research Corporation (OAR).
0015  *
0016  * Redistribution and use in source and binary forms, with or without
0017  * modification, are permitted provided that the following conditions
0018  * are met:
0019  * 1. Redistributions of source code must retain the above copyright
0020  *    notice, this list of conditions and the following disclaimer.
0021  * 2. Redistributions in binary form must reproduce the above copyright
0022  *    notice, this list of conditions and the following disclaimer in the
0023  *    documentation and/or other materials provided with the distribution.
0024  *
0025  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0026  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0027  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0028  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0029  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0030  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0031  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0032  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0033  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0034  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0035  * POSSIBILITY OF SUCH DAMAGE.
0036  */
0037
0038 #ifdef HAVE_CONFIG_H
0039 #include "config.h"
0040 #endif
0041
0042 #include <rtems/score/corebarrierimpl.h>
0043 #include <rtems/score/statesimpl.h>
0044 #include <rtems/score/threadimpl.h>
0045 #include <rtems/score/threadqops.h>
0046
0047 static void _CORE_barrier_Thread_queue_extract(
0048   Thread_queue_Queue   *queue,
0049   Thread_Control       *the_thread,
0050   Thread_queue_Context *queue_context
0051 )
0052 {
0053   CORE_barrier_Control *the_barrier;
0054
0055   the_barrier = RTEMS_CONTAINER_OF(
0056     queue,
0057     CORE_barrier_Control,
0058     Wait_queue.Queue
0059   );
0060   --the_barrier->number_of_waiting_threads;
0061   _Thread_queue_FIFO_extract(
0062     &the_barrier->Wait_queue.Queue,
0063     the_thread,
0064     queue_context
0065   );
0066 }
0067
0068 const Thread_queue_Operations _CORE_barrier_Thread_queue_operations = {
0069   .priority_actions = _Thread_queue_Do_nothing_priority_actions,
0070   .enqueue = _Thread_queue_FIFO_enqueue,
0071   .extract = _CORE_barrier_Thread_queue_extract,
0072   .surrender = _Thread_queue_FIFO_surrender,
0073   .first = _Thread_queue_FIFO_first
0074 };
0075
0076 Status_Control _CORE_barrier_Seize(
0077   CORE_barrier_Control *the_barrier,
0078   Thread_Control       *executing,
0079   bool                  wait,
0080   Thread_queue_Context *queue_context
0081 )
0082 {
0083   uint32_t new_number_of_waiting_threads;
0084
0085   _CORE_barrier_Acquire_critical( the_barrier, queue_context );
0086
0087   /*
0088    * In theory, this calculation can overflow.  If this happens, then about 4
0089    * billion threads are accidentally released.  Currently, the system limit
0090    * for threads is a bit lower with three times OBJECTS_INDEX_MASK - 1.
0091    */
0092   new_number_of_waiting_threads = the_barrier->number_of_waiting_threads + 1;
0093
0094   if ( new_number_of_waiting_threads == the_barrier->maximum_count ) {
0095     _CORE_barrier_Surrender( the_barrier, queue_context );
0096     return STATUS_BARRIER_AUTOMATICALLY_RELEASED;
0097   } else {
0098     the_barrier->number_of_waiting_threads = new_number_of_waiting_threads;
0099     _Thread_queue_Context_set_thread_state(
0100       queue_context,
0101       STATES_WAITING_FOR_BARRIER
0102     );
0103     _Thread_queue_Enqueue(
0104       &the_barrier->Wait_queue.Queue,
0105       &_CORE_barrier_Thread_queue_operations,
0106       executing,
0107       queue_context
0108     );
0109     return _Thread_Wait_get_status( executing );
0110   }
0111 }