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/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup RTEMSScoreAtomic
*
* @brief This source file contains the implementation of
* _Libatomic_Protect_start() and _Libatomic_Protect_end().
*/
/*
* Copyright (c) 2016 embedded brains GmbH. All rights reserved.
*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <machine/_libatomic.h>
#include <rtems/score/apimutex.h>
#include <rtems/score/atomic.h>
#include <rtems/score/isrlevel.h>
#if defined(RTEMS_SMP)
/*
* For real SMP targets this is not useful. The main purpose is support for
* testing on simulators like SIS.
*/
static Atomic_Flag _Libatomic_The_one_lock = ATOMIC_INITIALIZER_FLAG;
#endif
__uint32_t _Libatomic_Protect_start( void *ptr )
{
ISR_Level isr_level;
(void) ptr;
_ISR_Local_disable( isr_level );
#if defined(RTEMS_SMP)
while (
_Atomic_Flag_test_and_set( &_Libatomic_The_one_lock, ATOMIC_ORDER_SEQ_CST )
) {
/* Next try. Yes, a TAS spin lock implementation is stupid. */
}
#endif
return isr_level;
}
void _Libatomic_Protect_end( void *ptr, __uint32_t isr_level )
{
(void) ptr;
#if defined(RTEMS_SMP)
_Atomic_Flag_clear( &_Libatomic_The_one_lock, ATOMIC_ORDER_SEQ_CST );
#endif
_ISR_Local_enable( isr_level );
}
static API_Mutex_Control _Libatomic_Mutex =
API_MUTEX_INITIALIZER( "_Libatomic" );
void _Libatomic_Lock_n( void *ptr, __size_t n )
{
(void) ptr;
(void) n;
_API_Mutex_Lock( &_Libatomic_Mutex );
}
void _Libatomic_Unlock_n( void *ptr, __size_t n )
{
(void) ptr;
(void) n;
_API_Mutex_Unlock( &_Libatomic_Mutex );
}
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