score/src/threadstartmultitasking.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup RTEMSScoreThread
0007  *
0008  * @brief This source file contains the implementation of
0009  *   _Thread_Start_multitasking().
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/threadimpl.h>
0043 #include <rtems/score/assert.h>
0044 #include <rtems/score/smpimpl.h>
0045
0046 void _Thread_Start_multitasking( void )
0047 {
0048   Per_CPU_Control *cpu_self = _Per_CPU_Get();
0049   Thread_Control  *heir;
0050
0051 #if defined(RTEMS_SMP)
0052   _Per_CPU_Set_state( cpu_self, PER_CPU_STATE_UP );
0053   _SMP_Try_to_process_message( cpu_self, SMP_MESSAGE_FORCE_PROCESSING );
0054 #endif
0055
0056   heir = _Thread_Get_heir_and_make_it_executing( cpu_self );
0057
0058   _Profiling_Thread_dispatch_disable( cpu_self, 0 );
0059
0060 #if defined(RTEMS_SMP)
0061   _CPU_SMP_Prepare_start_multitasking();
0062 #endif
0063
0064 #if defined(_CPU_Start_multitasking)
0065   _CPU_Start_multitasking( &heir->Registers );
0066 #elif defined(RTEMS_SMP)
0067 #if CPU_ENABLE_ROBUST_THREAD_DISPATCH == TRUE
0068 #error "The CPU port has to provide _CPU_Start_multitasking()"
0069 #endif
0070   {
0071     Context_Control trash;
0072
0073     /*
0074      * Mark the trash context as executing to not confuse the
0075      * _CPU_Context_switch().  On SMP configurations the context switch
0076      * contains a special hand over section to atomically switch from the
0077      * executing to the currently selected heir thread.
0078      */
0079     _CPU_Context_Set_is_executing( &trash, true );
0080     _CPU_Context_switch_no_return( &trash, &heir->Registers );
0081     RTEMS_UNREACHABLE();
0082   }
0083 #else
0084   _CPU_Context_Restart_self( &heir->Registers );
0085 #endif
0086 }