rtems/score/context.h

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /**
0004  * @file
0005  *
0006  * @ingroup RTEMSScoreContext
0007  *
0008  * @brief This header file provides the interfaces of the
0009  *   @ref RTEMSScoreContext.
0010  */
0011
0012 /*
0013  *  COPYRIGHT (c) 1989-2011.
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 #ifndef _RTEMS_SCORE_CONTEXT_H
0039 #define _RTEMS_SCORE_CONTEXT_H
0040
0041 /**
0042  * @defgroup RTEMSScoreContext Context Handler
0043  *
0044  * @ingroup RTEMSScore
0045  *
0046  * @brief This group contains the Context Handler implementation.
0047  *
0048  * This handler encapsulates functionality which abstracts thread context
0049  * management in a portable manner.
0050  *
0051  * The context switch needed variable is contained in the per cpu
0052  * data structure.
0053  *
0054  * @{
0055  */
0056
0057 #ifdef __cplusplus
0058 extern "C" {
0059 #endif
0060
0061 #include <rtems/score/cpu.h>
0062
0063 /**
0064  *  @brief Size of floating point context area.
0065  *
0066  *  This constant defines the number of bytes required
0067  *  to store a full floating point context.
0068  */
0069 #if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
0070   #define CONTEXT_FP_SIZE \
0071     RTEMS_ALIGN_UP( CPU_CONTEXT_FP_SIZE, CPU_STACK_ALIGNMENT )
0072 #else
0073   #define CONTEXT_FP_SIZE 0
0074 #endif
0075
0076 /**
0077  *  @brief Initialize context area.
0078  *
0079  *  This routine initializes @a _the_context such that the stack
0080  *  pointer, interrupt level, and entry point are correct for the
0081  *  thread's initial state.
0082  *
0083  *  @param[in] _the_context will be initialized
0084  *  @param[in] _stack is the lowest physical address of the thread's
0085  *         context
0086  *  @param[in] _size is the size in octets of the thread's context
0087  *  @param[in] _isr is the ISR enable level for this thread
0088  *  @param[in] _entry is this thread's entry point
0089  *  @param[in] _is_fp is set to true if this thread has floating point
0090  *         enabled
0091  *  @param[in] _tls_area The thread-local storage (TLS) area begin.
0092  */
0093 #define _Context_Initialize( _the_context, _stack, _size, _isr, _entry, \
0094   _is_fp, _tls_area ) \
0095     _CPU_Context_Initialize( _the_context, _stack, _size, _isr, _entry, \
0096       _is_fp, _tls_area )
0097
0098 /**
0099  *  This macro is invoked from _Thread_Handler to do whatever CPU
0100  *  specific magic is required that must be done in the context of
0101  *  the thread when it starts.
0102  *
0103  *  If the CPU architecture does not require any magic, then this
0104  *  macro is empty.
0105  */
0106
0107 #if defined(_CPU_Context_Initialization_at_thread_begin)
0108   #define _Context_Initialization_at_thread_begin() \
0109      _CPU_Context_Initialization_at_thread_begin()
0110 #else
0111   #define _Context_Initialization_at_thread_begin()
0112 #endif
0113
0114 /**
0115  *  @brief Perform context switch.
0116  *
0117  *  This routine saves the current context into the @a _executing
0118  *  context record and restores the context specified by @a _heir.
0119  *
0120  *  @param[in] _executing is the currently executing thread's context
0121  *  @param[in] _heir is the context of the thread to be switched to
0122  */
0123 #define _Context_Switch( _executing, _heir ) \
0124    _CPU_Context_switch( _executing, _heir )
0125
0126 /**
0127  *  @brief Restart currently executing thread.
0128  *
0129  *  This routine restarts the calling thread by restoring its initial
0130  *  stack pointer and returning to the thread's entry point.
0131  *
0132  *  @param[in] _the_context is the context of the thread to restart
0133  */
0134 #define _Context_Restart_self( _the_context ) \
0135    _CPU_Context_Restart_self( _the_context )
0136
0137 /**
0138  *  @brief Initialize floating point context area.
0139  *
0140  *  This routine initializes the floating point context save
0141  *  area to contain an initial known state.
0142  *
0143  *  @param[in] _fp_area is the base address of the floating point
0144  *         context save area to initialize.
0145  */
0146 #define _Context_Initialize_fp( _fp_area ) \
0147    _CPU_Context_Initialize_fp( _fp_area )
0148
0149 /**
0150  *  @brief Restore floating point context area.
0151  *
0152  *  This routine restores the floating point context contained
0153  *  in the @a _fp area.  It is assumed that the current
0154  *  floating point context has been saved by a previous invocation
0155  *  of @a _Context_Save_fp.
0156  *
0157  *  @param[in] _fp points to the floating point context area to restore.
0158  */
0159 #define _Context_Restore_fp( _fp ) \
0160    _CPU_Context_restore_fp( _fp )
0161
0162 /**
0163  *  @brief Save floating point context area.
0164  *
0165  *  This routine saves the current floating point context
0166  *  in the @a _fp area.
0167  *
0168  *  @param[in] _fp points to the floating point context area to restore.
0169  */
0170 #define _Context_Save_fp( _fp ) \
0171    _CPU_Context_save_fp( _fp )
0172
0173 #if defined(_CPU_Context_Destroy)
0174   #define _Context_Destroy( _the_thread, _the_context ) \
0175     _CPU_Context_Destroy( _the_thread, _the_context )
0176 #else
0177   #define _Context_Destroy( _the_thread, _the_context )
0178 #endif
0179
0180 #ifdef __cplusplus
0181 }
0182 #endif
0183
0184 /** @} */
0185
0186 #endif
0187 /* end of include file */