/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup RTEMSScoreScheduler
*
* @brief This header file provides interfaces of the supporting the
* implementation of uniprocessor schedulers.
*/
/*
* Copyright (C) 2010 Gedare Bloom.
* Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
* Copyright (C) 2014, 2022 embedded brains GmbH
*
* 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.
*
* 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.
*/
#ifndef _RTEMS_SCORE_SCHEDULERUNIIMPL_H
#define _RTEMS_SCORE_SCHEDULERUNIIMPL_H
#include <rtems/score/schedulerimpl.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @addtogroup RTEMSScoreScheduler
*
* @{
*/
/**
* @brief Updates the heir thread of the processor.
*
* @param[in, out] heir is the current heir thread.
* @param[in, out] new_heir is the new heir thread.
*/
RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Update_heir(
Thread_Control *heir,
Thread_Control *new_heir
)
{
_Assert( heir != new_heir );
#if defined(RTEMS_SMP)
/*
* We need this state only for _Thread_Get_CPU_time_used_locked(). Cannot
* use _Scheduler_Thread_change_state() since THREAD_SCHEDULER_BLOCKED to
* THREAD_SCHEDULER_BLOCKED state changes are illegal for the real SMP
* schedulers.
*/
heir->Scheduler.state = THREAD_SCHEDULER_BLOCKED;
new_heir->Scheduler.state = THREAD_SCHEDULER_SCHEDULED;
#endif
_Thread_Update_CPU_time_used( heir, _Thread_Get_CPU( heir ) );
_Thread_Heir = new_heir;
_Thread_Dispatch_necessary = true;
}
/**
* @brief Updates the heir thread of the processor if the current heir is
* not equal to the new heir thread.
*
* The update takes place even if the current heir thread is not preemptible.
*
* @param[in, out] new_heir is the new heir thread.
*/
RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Update_heir_if_necessary(
Thread_Control *new_heir
)
{
Thread_Control *heir = _Thread_Heir;
if ( heir != new_heir ) {
_Scheduler_uniprocessor_Update_heir( heir, new_heir );
}
}
/**
* @brief Updates the heir thread of the processor if the current heir thread
* is preemptible.
*
* @param[in, out] heir is the current heir thread.
* @param[in, out] new_heir is the new heir thread.
*/
RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Update_heir_if_preemptible(
Thread_Control *heir,
Thread_Control *new_heir
)
{
if ( heir != new_heir && heir->is_preemptible ) {
_Scheduler_uniprocessor_Update_heir( heir, new_heir );
}
}
/**
* @brief Blocks the thread.
*
* @param scheduler is the scheduler.
* @param the_thread is the thread to block.
* @param node is the scheduler node of the thread.
* @param extract is the handler to extract the thread.
* @param get_highest_ready is the handler to get the highest ready thread.
*/
RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Block(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Scheduler_Node *node,
void ( *extract )(
const Scheduler_Control *,
Thread_Control *,
Scheduler_Node *
),
Thread_Control *( *get_highest_ready )( const Scheduler_Control * )
)
{
( *extract )( scheduler, the_thread, node );
/* TODO: flash critical section? */
if ( _Thread_Is_heir( the_thread ) ) {
Thread_Control *highest_ready;
highest_ready = ( *get_highest_ready )( scheduler );
_Scheduler_uniprocessor_Update_heir( _Thread_Heir, highest_ready );
}
}
/**
* @brief Schedule the unblocked thread if it is the highest ready thread.
*
* @param scheduler is the scheduler.
* @param the_thread is the thread.
* @param priority is the priority of the thread.
*/
RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Unblock(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Priority_Control priority
)
{
Thread_Control *heir;
heir = _Thread_Heir;
/*
* If the thread is more important than the heir, then we have a new heir.
* This may or may not result in a context switch. If the current heir
* thread is preemptible, then we need to do a context switch.
*/
if ( priority < _Thread_Get_priority( heir ) ) {
_Scheduler_uniprocessor_Update_heir_if_preemptible( heir, the_thread );
}
}
/**
* @brief Schedules the highest ready thread if the current heir thread of the
* processor is preemptible.
*
* @param scheduler is the scheduler.
* @param get_highest_ready is the handler to get the highest ready thread.
*/
RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Schedule(
const Scheduler_Control *scheduler,
Thread_Control *( *get_highest_ready )( const Scheduler_Control * )
)
{
Thread_Control *highest_ready;
highest_ready = ( *get_highest_ready )( scheduler );
_Scheduler_uniprocessor_Update_heir_if_preemptible(
_Thread_Heir,
highest_ready
);
}
/**
* @brief Yields to the highest ready thread.
*
* @param scheduler is the scheduler.
* @param get_highest_ready is the handler to get the highest ready thread.
*/
RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Yield(
const Scheduler_Control *scheduler,
Thread_Control *( *get_highest_ready )( const Scheduler_Control * )
)
{
Thread_Control *highest_ready;
highest_ready = ( *get_highest_ready )( scheduler );
_Scheduler_uniprocessor_Update_heir_if_necessary( highest_ready );
}
/** @} */
#ifdef __cplusplus
}
#endif
#endif /* _RTEMS_SCORE_SCHEDULERUNIIMPL_H */
