1 | /* |
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2 | * Semaphore Manager |
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3 | * |
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4 | * DESCRIPTION: |
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5 | * |
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6 | * This package is the implementation of the Semaphore Manager. |
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7 | * This manager utilizes standard Dijkstra counting semaphores to provide |
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8 | * synchronization and mutual exclusion capabilities. |
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9 | * |
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10 | * Directives provided are: |
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11 | * |
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12 | * + create a semaphore |
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13 | * + get an ID of a semaphore |
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14 | * + delete a semaphore |
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15 | * + acquire a semaphore |
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16 | * + release a semaphore |
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17 | * |
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18 | * COPYRIGHT (c) 1989-1999. |
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19 | * On-Line Applications Research Corporation (OAR). |
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20 | * |
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21 | * The license and distribution terms for this file may be |
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22 | * found in the file LICENSE in this distribution or at |
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23 | * http://www.rtems.com/license/LICENSE. |
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24 | * |
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25 | * $Id$ |
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26 | */ |
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27 | |
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28 | #if HAVE_CONFIG_H |
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29 | #include "config.h" |
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30 | #endif |
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31 | |
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32 | #include <rtems/system.h> |
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33 | #include <rtems/rtems/status.h> |
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34 | #include <rtems/rtems/support.h> |
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35 | #include <rtems/rtems/attr.h> |
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36 | #include <rtems/score/isr.h> |
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37 | #include <rtems/score/object.h> |
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38 | #include <rtems/rtems/options.h> |
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39 | #include <rtems/rtems/sem.h> |
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40 | #include <rtems/score/coremutex.h> |
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41 | #include <rtems/score/coresem.h> |
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42 | #include <rtems/score/states.h> |
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43 | #include <rtems/score/thread.h> |
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44 | #include <rtems/score/threadq.h> |
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45 | #if defined(RTEMS_MULTIPROCESSING) |
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46 | #include <rtems/score/mpci.h> |
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47 | #endif |
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48 | #include <rtems/score/sysstate.h> |
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49 | |
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50 | #include <rtems/score/interr.h> |
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51 | |
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52 | /*PAGE |
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53 | * |
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54 | * rtems_semaphore_create |
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55 | * |
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56 | * This directive creates a semaphore and sets the initial value based |
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57 | * on the given count. A semaphore id is returned. |
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58 | * |
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59 | * Input parameters: |
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60 | * name - user defined semaphore name |
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61 | * count - initial count of semaphore |
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62 | * attribute_set - semaphore attributes |
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63 | * priority_ceiling - semaphore's ceiling priority |
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64 | * id - pointer to semaphore id |
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65 | * |
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66 | * Output parameters: |
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67 | * id - semaphore id |
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68 | * RTEMS_SUCCESSFUL - if successful |
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69 | * error code - if unsuccessful |
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70 | */ |
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71 | |
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72 | rtems_status_code rtems_semaphore_create( |
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73 | rtems_name name, |
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74 | uint32_t count, |
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75 | rtems_attribute attribute_set, |
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76 | rtems_task_priority priority_ceiling, |
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77 | rtems_id *id |
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78 | ) |
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79 | { |
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80 | register Semaphore_Control *the_semaphore; |
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81 | CORE_mutex_Attributes the_mutex_attributes; |
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82 | CORE_semaphore_Attributes the_semaphore_attributes; |
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83 | uint32_t lock; |
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84 | |
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85 | if ( !rtems_is_name_valid( name ) ) |
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86 | return RTEMS_INVALID_NAME; |
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87 | |
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88 | if ( !id ) |
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89 | return RTEMS_INVALID_ADDRESS; |
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90 | |
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91 | #if defined(RTEMS_MULTIPROCESSING) |
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92 | if ( _Attributes_Is_global( attribute_set ) ) { |
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93 | |
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94 | if ( !_System_state_Is_multiprocessing ) |
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95 | return RTEMS_MP_NOT_CONFIGURED; |
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96 | |
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97 | if ( _Attributes_Is_inherit_priority( attribute_set ) ) |
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98 | return RTEMS_NOT_DEFINED; |
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99 | |
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100 | } else |
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101 | #endif |
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102 | |
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103 | if ( _Attributes_Is_inherit_priority( attribute_set ) || |
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104 | _Attributes_Is_priority_ceiling( attribute_set ) ) { |
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105 | |
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106 | if ( ! ( (_Attributes_Is_binary_semaphore( attribute_set ) || |
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107 | _Attributes_Is_simple_binary_semaphore( attribute_set )) && |
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108 | |
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109 | _Attributes_Is_priority( attribute_set ) ) ) |
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110 | return RTEMS_NOT_DEFINED; |
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111 | |
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112 | } |
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113 | |
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114 | if ( !_Attributes_Is_counting_semaphore( attribute_set ) && ( count > 1 ) ) |
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115 | return RTEMS_INVALID_NUMBER; |
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116 | |
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117 | _Thread_Disable_dispatch(); /* prevents deletion */ |
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118 | |
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119 | the_semaphore = _Semaphore_Allocate(); |
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120 | |
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121 | if ( !the_semaphore ) { |
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122 | _Thread_Enable_dispatch(); |
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123 | return RTEMS_TOO_MANY; |
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124 | } |
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125 | |
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126 | #if defined(RTEMS_MULTIPROCESSING) |
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127 | if ( _Attributes_Is_global( attribute_set ) && |
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128 | ! ( _Objects_MP_Allocate_and_open( &_Semaphore_Information, name, |
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129 | the_semaphore->Object.id, false ) ) ) { |
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130 | _Semaphore_Free( the_semaphore ); |
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131 | _Thread_Enable_dispatch(); |
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132 | return RTEMS_TOO_MANY; |
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133 | } |
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134 | #endif |
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135 | |
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136 | the_semaphore->attribute_set = attribute_set; |
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137 | |
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138 | /* |
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139 | * If it is not a counting semaphore, then it is either a |
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140 | * simple binary semaphore or a more powerful mutex style binary |
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141 | * semaphore. |
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142 | */ |
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143 | |
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144 | if ( !_Attributes_Is_counting_semaphore( attribute_set ) ) { |
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145 | if ( _Attributes_Is_inherit_priority( attribute_set ) ) |
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146 | the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT; |
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147 | else if ( _Attributes_Is_priority_ceiling( attribute_set ) ) |
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148 | the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING; |
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149 | else if ( _Attributes_Is_priority( attribute_set ) ) |
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150 | the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_PRIORITY; |
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151 | else |
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152 | the_mutex_attributes.discipline = CORE_MUTEX_DISCIPLINES_FIFO; |
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153 | |
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154 | |
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155 | if ( _Attributes_Is_binary_semaphore( attribute_set ) ) { |
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156 | the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_ACQUIRES; |
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157 | |
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158 | switch ( the_mutex_attributes.discipline ) { |
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159 | case CORE_MUTEX_DISCIPLINES_FIFO: |
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160 | case CORE_MUTEX_DISCIPLINES_PRIORITY: |
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161 | the_mutex_attributes.only_owner_release = false; |
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162 | break; |
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163 | case CORE_MUTEX_DISCIPLINES_PRIORITY_CEILING: |
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164 | case CORE_MUTEX_DISCIPLINES_PRIORITY_INHERIT: |
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165 | the_mutex_attributes.only_owner_release = true; |
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166 | break; |
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167 | } |
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168 | } else { |
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169 | the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_BLOCKS; |
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170 | the_mutex_attributes.only_owner_release = false; |
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171 | } |
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172 | |
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173 | the_mutex_attributes.priority_ceiling = priority_ceiling; |
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174 | |
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175 | if ( count == 1 ) |
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176 | lock = CORE_MUTEX_UNLOCKED; |
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177 | else |
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178 | lock = CORE_MUTEX_LOCKED; |
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179 | |
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180 | _CORE_mutex_Initialize( |
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181 | &the_semaphore->Core_control.mutex, |
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182 | &the_mutex_attributes, |
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183 | lock |
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184 | ); |
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185 | } else { |
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186 | if ( _Attributes_Is_priority( attribute_set ) ) |
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187 | the_semaphore_attributes.discipline = CORE_SEMAPHORE_DISCIPLINES_PRIORITY; |
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188 | else |
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189 | the_semaphore_attributes.discipline = CORE_SEMAPHORE_DISCIPLINES_FIFO; |
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190 | |
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191 | /* |
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192 | * This effectively disables limit checking. |
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193 | */ |
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194 | |
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195 | the_semaphore_attributes.maximum_count = 0xFFFFFFFF; |
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196 | |
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197 | /* |
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198 | * The following are just to make Purify happy. |
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199 | */ |
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200 | |
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201 | the_mutex_attributes.lock_nesting_behavior = CORE_MUTEX_NESTING_ACQUIRES; |
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202 | the_mutex_attributes.priority_ceiling = PRIORITY_MINIMUM; |
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203 | |
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204 | _CORE_semaphore_Initialize( |
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205 | &the_semaphore->Core_control.semaphore, |
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206 | &the_semaphore_attributes, |
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207 | count |
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208 | ); |
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209 | } |
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210 | |
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211 | _Objects_Open( |
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212 | &_Semaphore_Information, |
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213 | &the_semaphore->Object, |
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214 | (Objects_Name) name |
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215 | ); |
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216 | |
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217 | *id = the_semaphore->Object.id; |
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218 | |
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219 | #if defined(RTEMS_MULTIPROCESSING) |
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220 | if ( _Attributes_Is_global( attribute_set ) ) |
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221 | _Semaphore_MP_Send_process_packet( |
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222 | SEMAPHORE_MP_ANNOUNCE_CREATE, |
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223 | the_semaphore->Object.id, |
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224 | name, |
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225 | 0 /* Not used */ |
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226 | ); |
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227 | #endif |
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228 | _Thread_Enable_dispatch(); |
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229 | return RTEMS_SUCCESSFUL; |
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230 | } |
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