1 | /** |
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2 | * @file |
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3 | * |
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4 | * @ingroup ScoreMutex |
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5 | * |
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6 | * @brief CORE Mutex Implementation |
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7 | */ |
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8 | |
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9 | /* |
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10 | * COPYRIGHT (c) 1989-2009. |
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11 | * On-Line Applications Research Corporation (OAR). |
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12 | * |
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13 | * The license and distribution terms for this file may be |
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14 | * found in the file LICENSE in this distribution or at |
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15 | * http://www.rtems.org/license/LICENSE. |
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16 | */ |
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17 | |
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18 | #ifndef _RTEMS_SCORE_COREMUTEXIMPL_H |
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19 | #define _RTEMS_SCORE_COREMUTEXIMPL_H |
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20 | |
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21 | #include <rtems/score/coremutex.h> |
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22 | #include <rtems/score/chainimpl.h> |
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23 | #include <rtems/score/sysstate.h> |
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24 | #include <rtems/score/threadimpl.h> |
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25 | #include <rtems/score/threadqimpl.h> |
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26 | |
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27 | #ifdef __cplusplus |
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28 | extern "C" { |
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29 | #endif |
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30 | |
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31 | /** |
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32 | * @addtogroup ScoreMutex |
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33 | */ |
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34 | /**@{**/ |
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35 | |
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36 | /** |
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37 | * @brief The possible Mutex handler return statuses. |
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38 | * |
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39 | * This enumerated type defines the possible Mutex handler return statuses. |
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40 | */ |
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41 | typedef enum { |
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42 | /** This status indicates that the operation completed successfully. */ |
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43 | CORE_MUTEX_STATUS_SUCCESSFUL, |
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44 | /** This status indicates that the calling task did not want to block |
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45 | * and the operation was unable to complete immediately because the |
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46 | * resource was unavailable. |
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47 | */ |
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48 | CORE_MUTEX_STATUS_UNSATISFIED_NOWAIT, |
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49 | #if defined(RTEMS_POSIX_API) |
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50 | /** This status indicates that an attempt was made to relock a mutex |
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51 | * for which nesting is not configured. |
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52 | */ |
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53 | CORE_MUTEX_STATUS_NESTING_NOT_ALLOWED, |
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54 | #endif |
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55 | /** This status indicates that an attempt was made to release a mutex |
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56 | * by a thread other than the thread which locked it. |
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57 | */ |
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58 | CORE_MUTEX_STATUS_NOT_OWNER_OF_RESOURCE, |
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59 | /** This status indicates that the thread was blocked waiting for an |
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60 | * operation to complete and the mutex was deleted. |
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61 | */ |
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62 | CORE_MUTEX_WAS_DELETED, |
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63 | /** This status indicates that the calling task was willing to block |
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64 | * but the operation was unable to complete within the time allotted |
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65 | * because the resource never became available. |
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66 | */ |
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67 | CORE_MUTEX_TIMEOUT, |
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68 | |
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69 | /** This status indicates that a thread of logically greater importance |
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70 | * than the ceiling priority attempted to lock this mutex. |
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71 | */ |
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72 | CORE_MUTEX_STATUS_CEILING_VIOLATED |
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73 | |
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74 | } CORE_mutex_Status; |
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75 | |
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76 | /** |
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77 | * @brief The last status value. |
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78 | * |
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79 | * This is the last status value. |
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80 | */ |
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81 | #define CORE_MUTEX_STATUS_LAST CORE_MUTEX_STATUS_CEILING_VIOLATED |
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82 | |
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83 | /** |
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84 | * @brief Initializes the mutex based on the parameters passed. |
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85 | * |
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86 | * This routine initializes the mutex based on the parameters passed. |
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87 | * |
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88 | * @param[in,out] the_mutex is the mutex to initalize |
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89 | * @param[in,out] executing The currently executing thread. |
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90 | * @param[in] the_mutex_attributes is the attributes associated with this |
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91 | * mutex instance |
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92 | * @param[in] initially_locked If true, then the mutex is initially locked by |
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93 | * the executing thread. |
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94 | * |
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95 | * @retval This method returns CORE_MUTEX_STATUS_SUCCESSFUL if successful. |
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96 | */ |
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97 | CORE_mutex_Status _CORE_mutex_Initialize( |
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98 | CORE_mutex_Control *the_mutex, |
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99 | Thread_Control *executing, |
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100 | const CORE_mutex_Attributes *the_mutex_attributes, |
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101 | bool initially_locked |
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102 | ); |
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103 | |
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104 | RTEMS_INLINE_ROUTINE void _CORE_mutex_Destroy( CORE_mutex_Control *the_mutex ) |
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105 | { |
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106 | _Thread_queue_Destroy( &the_mutex->Wait_queue ); |
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107 | } |
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108 | |
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109 | RTEMS_INLINE_ROUTINE void _CORE_mutex_Acquire_critical( |
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110 | CORE_mutex_Control *the_mutex, |
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111 | ISR_lock_Context *lock_context |
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112 | ) |
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113 | { |
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114 | _Thread_queue_Acquire_critical( &the_mutex->Wait_queue, lock_context ); |
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115 | } |
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116 | |
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117 | RTEMS_INLINE_ROUTINE void _CORE_mutex_Release( |
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118 | CORE_mutex_Control *the_mutex, |
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119 | ISR_lock_Context *lock_context |
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120 | ) |
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121 | { |
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122 | _Thread_queue_Release( &the_mutex->Wait_queue, lock_context ); |
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123 | } |
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124 | |
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125 | /** |
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126 | * @brief Attempt to receive a unit from the_mutex. |
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127 | * |
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128 | * This routine attempts to receive a unit from the_mutex. |
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129 | * If a unit is available or if the wait flag is false, then the routine |
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130 | * returns. Otherwise, the calling task is blocked until a unit becomes |
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131 | * available. |
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132 | * |
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133 | * @param[in,out] executing The currently executing thread. |
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134 | * @param[in,out] the_mutex is the mutex to attempt to lock |
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135 | * @param[in] lock_context is the interrupt level |
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136 | * |
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137 | * @retval This routine returns 0 if "trylock" can resolve whether or not |
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138 | * the mutex is immediately obtained or there was an error attempting to |
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139 | * get it. It returns 1 to indicate that the caller cannot obtain |
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140 | * the mutex and will have to block to do so. |
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141 | * |
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142 | * @note For performance reasons, this routine is implemented as |
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143 | * a macro that uses two support routines. |
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144 | */ |
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145 | |
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146 | RTEMS_INLINE_ROUTINE int _CORE_mutex_Seize_interrupt_trylock_body( |
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147 | CORE_mutex_Control *the_mutex, |
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148 | Thread_Control *executing, |
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149 | ISR_lock_Context *lock_context |
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150 | ); |
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151 | |
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152 | #if defined(__RTEMS_DO_NOT_INLINE_CORE_MUTEX_SEIZE__) |
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153 | /** |
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154 | * @brief Interrupt trylock CORE mutex seize. |
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155 | * |
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156 | * When doing test coverage analysis or trying to minimize the code |
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157 | * space for RTEMS, it is often helpful to not inline this method |
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158 | * multiple times. It is fairly large and has a high branch complexity |
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159 | * which makes it harder to get full binary test coverage. |
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160 | * |
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161 | * @param[in] the_mutex will attempt to lock |
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162 | * @param[in] _executing points to the executing thread |
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163 | * @param[in] level_p is the interrupt level |
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164 | */ |
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165 | int _CORE_mutex_Seize_interrupt_trylock( |
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166 | CORE_mutex_Control *the_mutex, |
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167 | Thread_Control *executing, |
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168 | ISR_lock_Context *lock_context |
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169 | ); |
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170 | #else |
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171 | /** |
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172 | * The default is to favor speed and inlining this definitely saves |
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173 | * a few instructions. This is very important for mutex performance. |
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174 | * |
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175 | * @param[in] _mutex will attempt to lock |
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176 | * @param[in] _executing points to the executing thread |
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177 | * @param[in] _lock_context is the interrupt level |
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178 | */ |
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179 | #define _CORE_mutex_Seize_interrupt_trylock( _mutex, _executing, _lock_context ) \ |
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180 | _CORE_mutex_Seize_interrupt_trylock_body( _mutex, _executing, _lock_context ) |
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181 | #endif |
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182 | |
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183 | /** |
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184 | * @brief Performs the blocking portion of a mutex obtain. |
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185 | * |
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186 | * This routine performs the blocking portion of a mutex obtain. |
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187 | * It is an actual subroutine and is not implemented as something |
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188 | * that may be inlined. |
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189 | * |
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190 | * @param[in,out] the_mutex is the mutex to attempt to lock |
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191 | * @param[in,out] executing The currently executing thread. |
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192 | * @param[in] timeout is the maximum number of ticks to block |
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193 | * @param[in] lock_context is the interrupt level |
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194 | */ |
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195 | void _CORE_mutex_Seize_interrupt_blocking( |
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196 | CORE_mutex_Control *the_mutex, |
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197 | Thread_Control *executing, |
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198 | Watchdog_Interval timeout, |
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199 | ISR_lock_Context *lock_context |
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200 | ); |
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201 | |
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202 | /** |
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203 | * @brief Verifies that a mutex blocking seize is performed safely. |
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204 | * |
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205 | * This macro is to verify that a mutex blocking seize is |
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206 | * performed from a safe system state. For example, one |
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207 | * cannot block inside an isr. |
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208 | * |
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209 | * @retval this method returns true if dispatch is in an unsafe state. |
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210 | */ |
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211 | #define _CORE_mutex_Check_dispatch_for_seize(_wait) \ |
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212 | (!_Thread_Dispatch_is_enabled() \ |
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213 | && (_wait) \ |
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214 | && (_System_state_Get() >= SYSTEM_STATE_UP)) |
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215 | |
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216 | /** |
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217 | * @brief Attempt to obtain the mutex. |
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218 | * |
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219 | * This routine attempts to obtain the mutex. If the mutex is available, |
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220 | * then it will return immediately. Otherwise, it will invoke the |
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221 | * support routine @a _Core_mutex_Seize_interrupt_blocking. |
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222 | * |
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223 | * @param[in] the_mutex is the mutex to attempt to lock |
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224 | * @param[in] wait is true if the thread is willing to wait |
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225 | * @param[in] timeout is the maximum number of ticks to block |
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226 | * @param[in] lock_context is a temporary variable used to contain the ISR |
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227 | * disable level cookie |
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228 | * |
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229 | * @note If the mutex is called from an interrupt service routine, |
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230 | * with context switching disabled, or before multitasking, |
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231 | * then a fatal error is generated. |
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232 | * |
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233 | * The logic on this routine is as follows: |
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234 | * |
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235 | * * If incorrect system state |
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236 | * return an error |
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237 | * * If mutex is available without any contention or blocking |
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238 | * obtain it with interrupts disabled and returned |
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239 | * * If the caller is willing to wait |
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240 | * then they are blocked. |
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241 | */ |
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242 | RTEMS_INLINE_ROUTINE void _CORE_mutex_Seize_body( |
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243 | CORE_mutex_Control *the_mutex, |
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244 | Thread_Control *executing, |
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245 | bool wait, |
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246 | Watchdog_Interval timeout, |
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247 | ISR_lock_Context *lock_context |
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248 | ) |
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249 | { |
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250 | if ( _CORE_mutex_Check_dispatch_for_seize( wait ) ) { |
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251 | _Terminate( |
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252 | INTERNAL_ERROR_CORE, |
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253 | false, |
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254 | INTERNAL_ERROR_MUTEX_OBTAIN_FROM_BAD_STATE |
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255 | ); |
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256 | } |
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257 | _CORE_mutex_Acquire_critical( the_mutex, lock_context ); |
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258 | if ( _CORE_mutex_Seize_interrupt_trylock( the_mutex, executing, lock_context ) ) { |
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259 | if ( !wait ) { |
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260 | _CORE_mutex_Release( the_mutex, lock_context ); |
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261 | executing->Wait.return_code = |
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262 | CORE_MUTEX_STATUS_UNSATISFIED_NOWAIT; |
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263 | } else { |
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264 | _CORE_mutex_Seize_interrupt_blocking( |
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265 | the_mutex, |
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266 | executing, |
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267 | timeout, |
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268 | lock_context |
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269 | ); |
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270 | } |
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271 | } |
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272 | } |
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273 | |
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274 | /** |
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275 | * This method is used to obtain a core mutex. |
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276 | * |
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277 | * @param[in] _the_mutex is the mutex to attempt to lock |
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278 | * @param[in] _executing The currently executing thread. |
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279 | * @param[in] _wait is true if the thread is willing to wait |
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280 | * @param[in] _timeout is the maximum number of ticks to block |
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281 | * @param[in] _lock_context is a temporary variable used to contain the ISR |
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282 | * disable level cookie |
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283 | */ |
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284 | #if defined(__RTEMS_DO_NOT_INLINE_CORE_MUTEX_SEIZE__) |
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285 | void _CORE_mutex_Seize( |
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286 | CORE_mutex_Control *_the_mutex, |
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287 | Thread_Control *_executing, |
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288 | bool _wait, |
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289 | Watchdog_Interval _timeout, |
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290 | ISR_lock_Context *_lock_context |
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291 | ); |
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292 | #else |
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293 | #define _CORE_mutex_Seize( \ |
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294 | _the_mutex, _executing, _wait, _timeout, _lock_context ) \ |
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295 | _CORE_mutex_Seize_body( \ |
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296 | _the_mutex, _executing, _wait, _timeout, _lock_context ) |
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297 | #endif |
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298 | |
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299 | CORE_mutex_Status _CORE_mutex_Do_surrender( |
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300 | CORE_mutex_Control *the_mutex, |
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301 | #if defined(RTEMS_MULTIPROCESSING) |
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302 | Thread_queue_MP_callout mp_callout, |
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303 | Objects_Id mp_id, |
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304 | #endif |
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305 | ISR_lock_Context *lock_context |
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306 | ); |
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307 | |
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308 | #if defined(RTEMS_MULTIPROCESSING) |
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309 | #define _CORE_mutex_Surrender( \ |
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310 | the_mutex, \ |
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311 | mp_callout, \ |
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312 | mp_id, \ |
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313 | lock_context \ |
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314 | ) \ |
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315 | _CORE_mutex_Do_surrender( \ |
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316 | the_mutex, \ |
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317 | mp_callout, \ |
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318 | mp_id, \ |
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319 | lock_context \ |
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320 | ) |
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321 | #else |
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322 | #define _CORE_mutex_Surrender( \ |
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323 | the_mutex, \ |
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324 | mp_callout, \ |
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325 | mp_id, \ |
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326 | lock_context \ |
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327 | ) \ |
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328 | _CORE_mutex_Do_surrender( \ |
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329 | the_mutex, \ |
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330 | lock_context \ |
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331 | ) |
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332 | #endif |
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333 | |
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334 | Thread_Control *_CORE_mutex_Was_deleted( |
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335 | Thread_Control *the_thread, |
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336 | Thread_queue_Queue *queue, |
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337 | ISR_lock_Context *lock_context |
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338 | ); |
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339 | |
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340 | Thread_Control *_CORE_mutex_Unsatisfied_nowait( |
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341 | Thread_Control *the_thread, |
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342 | Thread_queue_Queue *queue, |
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343 | ISR_lock_Context *lock_context |
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344 | ); |
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345 | |
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346 | /* Must be a macro due to the multiprocessing dependent parameters */ |
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347 | #define _CORE_mutex_Flush( \ |
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348 | the_mutex, \ |
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349 | filter, \ |
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350 | mp_callout, \ |
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351 | mp_id, \ |
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352 | lock_context \ |
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353 | ) \ |
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354 | _Thread_queue_Flush_critical( \ |
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355 | &( the_mutex )->Wait_queue.Queue, \ |
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356 | ( the_mutex )->operations, \ |
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357 | filter, \ |
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358 | mp_callout, \ |
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359 | mp_id, \ |
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360 | lock_context \ |
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361 | ) |
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362 | |
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363 | /** |
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364 | * @brief Is mutex locked. |
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365 | * |
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366 | * This routine returns true if the mutex specified is locked and false |
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367 | * otherwise. |
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368 | * |
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369 | * @param[in] the_mutex is the mutex to check. |
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370 | * |
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371 | * @retval true The mutex is locked. |
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372 | * @retval false The mutex is not locked. |
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373 | */ |
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374 | RTEMS_INLINE_ROUTINE bool _CORE_mutex_Is_locked( |
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375 | const CORE_mutex_Control *the_mutex |
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376 | ) |
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377 | { |
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378 | return the_mutex->holder != NULL; |
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379 | } |
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380 | |
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381 | RTEMS_INLINE_ROUTINE bool _CORE_mutex_Is_owner( |
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382 | const CORE_mutex_Control *the_mutex, |
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383 | const Thread_Control *the_thread |
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384 | ) |
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385 | { |
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386 | return the_mutex->holder == the_thread; |
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387 | } |
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388 | |
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389 | /** |
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390 | * @brief Does core mutex use FIFO blocking. |
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391 | * |
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392 | * This routine returns true if the mutex's wait discipline is FIFO and false |
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393 | * otherwise. |
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394 | * |
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395 | * @param[in] the_attribute is the attribute set of the mutex. |
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396 | * |
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397 | * @retval true The mutex is using FIFO blocking order. |
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398 | * @retval false The mutex is not using FIFO blocking order. |
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399 | */ |
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400 | RTEMS_INLINE_ROUTINE bool _CORE_mutex_Is_fifo( |
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401 | const CORE_mutex_Attributes *the_attribute |
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402 | ) |
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403 | { |
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404 | return the_attribute->discipline == CORE_MUTEX_DISCIPLINES_FIFO; |
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405 | } |
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406 | |
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407 | /** |
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408 | * @brief Doex core mutex use priority blocking. |
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409 | * |
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410 | * This routine returns true if the mutex's wait discipline is PRIORITY and |
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411 | * false otherwise. |
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412 | * |
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413 | * @param[in] the_attribute is the attribute set of the mutex. |
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414 | * |
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415 | * @retval true The mutex is using priority blocking order. |
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416 | * @retval false The mutex is not using priority blocking order. |
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417 | * |
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418 | */ |
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419 | RTEMS_INLINE_ROUTINE bool _CORE_mutex_Is_priority( |
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420 | const CORE_mutex_Attributes *the_attribute |
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421 | ) |
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422 | { |
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423 | return the_attribute->discipline == CORE_MUTEX_DISCIPLINES_PRIORITY; |
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424 | } |
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425 | |
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426 | /** |
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427 | * @brief Does mutex use priority inheritance. |
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428 | * |
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429 | * This routine returns true if the mutex's wait discipline is |
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430 | * INHERIT_PRIORITY and false otherwise. |
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431 | * |
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432 | * @param[in] the_attribute is the attribute set of the mutex. |
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433 | * |
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434 | * @retval true The mutex is using priority inheritance. |
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435 | * @retval false The mutex is not using priority inheritance. |
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436 | */ |
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437 | RTEMS_INLINE_ROUTINE bool _CORE_mutex_Is_inherit_priority( |
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438 | const CORE_mutex_Attributes *the_attribute |
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439 | ) |
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440 | { |
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441 | return the_attribute->discipline == CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT; |
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442 | } |
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443 | |
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444 | /** |
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445 | * @brief Does mutex use priority ceiling. |
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446 | * |
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447 | * This routine returns true if the mutex's wait discipline is |
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448 | * PRIORITY_CEILING and false otherwise. |
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449 | * |
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450 | * @param[in] the_attribute is the attribute set of the mutex. |
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451 | * |
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452 | * @retval true The mutex is using priority ceiling. |
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453 | * @retval false The mutex is not using priority ceiling. |
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454 | */ |
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455 | RTEMS_INLINE_ROUTINE bool _CORE_mutex_Is_priority_ceiling( |
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456 | const CORE_mutex_Attributes *the_attribute |
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457 | ) |
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458 | { |
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459 | return the_attribute->discipline == CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING; |
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460 | } |
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461 | |
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462 | /* |
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463 | * Seize Mutex with Quick Success Path |
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464 | * |
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465 | * NOTE: There is no MACRO version of this routine. A body is in |
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466 | * coremutexseize.c that is duplicated from the .inl by hand. |
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467 | * |
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468 | * NOTE: The Doxygen for this routine is in the .h file. |
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469 | */ |
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470 | |
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471 | RTEMS_INLINE_ROUTINE int _CORE_mutex_Seize_interrupt_trylock_body( |
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472 | CORE_mutex_Control *the_mutex, |
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473 | Thread_Control *executing, |
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474 | ISR_lock_Context *lock_context |
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475 | ) |
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476 | { |
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477 | /* disabled when you get here */ |
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478 | |
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479 | executing->Wait.return_code = CORE_MUTEX_STATUS_SUCCESSFUL; |
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480 | if ( !_CORE_mutex_Is_locked( the_mutex ) ) { |
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481 | the_mutex->holder = executing; |
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482 | the_mutex->nest_count = 1; |
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483 | if ( _CORE_mutex_Is_inherit_priority( &the_mutex->Attributes ) || |
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484 | _CORE_mutex_Is_priority_ceiling( &the_mutex->Attributes ) ){ |
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485 | executing->resource_count++; |
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486 | } |
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487 | |
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488 | if ( !_CORE_mutex_Is_priority_ceiling( &the_mutex->Attributes ) ) { |
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489 | _CORE_mutex_Release( the_mutex, lock_context ); |
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490 | return 0; |
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491 | } /* else must be CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING |
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492 | * |
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493 | * we possibly bump the priority of the current holder -- which |
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494 | * happens to be _Thread_Executing. |
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495 | */ |
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496 | { |
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497 | Priority_Control ceiling; |
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498 | Priority_Control current; |
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499 | |
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500 | ceiling = the_mutex->Attributes.priority_ceiling; |
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501 | current = executing->current_priority; |
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502 | if ( current == ceiling ) { |
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503 | _CORE_mutex_Release( the_mutex, lock_context ); |
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504 | return 0; |
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505 | } |
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506 | |
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507 | if ( current > ceiling ) { |
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508 | Per_CPU_Control *cpu_self; |
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509 | |
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510 | cpu_self = _Thread_Dispatch_disable_critical( lock_context ); |
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511 | _CORE_mutex_Release( the_mutex, lock_context ); |
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512 | _Thread_Raise_priority( executing, ceiling ); |
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513 | _Thread_Dispatch_enable( cpu_self ); |
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514 | return 0; |
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515 | } |
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516 | /* if ( current < ceiling ) */ { |
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517 | executing->Wait.return_code = CORE_MUTEX_STATUS_CEILING_VIOLATED; |
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518 | the_mutex->holder = NULL; |
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519 | the_mutex->nest_count = 0; /* undo locking above */ |
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520 | executing->resource_count--; /* undo locking above */ |
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521 | _CORE_mutex_Release( the_mutex, lock_context ); |
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522 | return 0; |
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523 | } |
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524 | } |
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525 | return 0; |
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526 | } |
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527 | |
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528 | /* |
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529 | * At this point, we know the mutex was not available. If this thread |
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530 | * is the thread that has locked the mutex, let's see if we are allowed |
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531 | * to nest access. |
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532 | */ |
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533 | if ( _Thread_Is_executing( the_mutex->holder ) ) { |
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534 | switch ( the_mutex->Attributes.lock_nesting_behavior ) { |
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535 | case CORE_MUTEX_NESTING_ACQUIRES: |
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536 | the_mutex->nest_count++; |
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537 | _CORE_mutex_Release( the_mutex, lock_context ); |
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538 | return 0; |
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539 | #if defined(RTEMS_POSIX_API) |
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540 | case CORE_MUTEX_NESTING_IS_ERROR: |
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541 | executing->Wait.return_code = CORE_MUTEX_STATUS_NESTING_NOT_ALLOWED; |
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542 | _CORE_mutex_Release( the_mutex, lock_context ); |
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543 | return 0; |
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544 | #endif |
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545 | case CORE_MUTEX_NESTING_BLOCKS: |
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546 | break; |
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547 | } |
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548 | } |
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549 | |
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550 | /* |
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551 | * The mutex is not available and the caller must deal with the possibility |
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552 | * of blocking. |
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553 | */ |
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554 | return 1; |
---|
555 | } |
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556 | |
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557 | /** @} */ |
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558 | |
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559 | #ifdef __cplusplus |
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560 | } |
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561 | #endif |
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562 | |
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563 | #endif |
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564 | /* end of include file */ |
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