1 | /* |
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2 | * remote_mutex.c - Access a POSIX mutex. |
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3 | * |
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4 | * Authors Alain Greiner (2016) |
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5 | * |
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6 | * Copyright (c) UPMC Sorbonne Universites |
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7 | * |
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8 | * This file is part of ALMOS-MKH. |
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9 | * |
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10 | * ALMOS-MKH is free software; you can redistribute it and/or modify it |
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11 | * under the terms of the GNU General Public License as published by |
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12 | * the Free Software Foundation; version 2.0 of the License. |
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13 | * |
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14 | * ALMOS-MKH is distributed in the hope that it will be useful, but |
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15 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
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16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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17 | * General Public License for more details. |
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18 | * |
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19 | * You should have received a copy of the GNU General Public License |
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20 | * along with ALMOS-MKH; if not, write to the Free Software Foundation, |
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21 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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22 | */ |
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23 | |
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24 | #include <hal_types.h> |
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25 | #include <hal_remote.h> |
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26 | #include <hal_special.h> |
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27 | #include <hal_irqmask.h> |
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28 | #include <thread.h> |
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29 | #include <cluster.h> |
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30 | #include <scheduler.h> |
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31 | #include <remote_mutex.h> |
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32 | |
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33 | ///////////////////////////////////////////////// |
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34 | xptr_t remote_mutex_from_ident( intptr_t ident ) |
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35 | { |
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36 | // get pointer on local process_descriptor |
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37 | process_t * process = CURRENT_THREAD->process; |
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38 | |
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39 | // get extended pointer on reference process |
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40 | xptr_t ref_xp = process->ref_xp; |
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41 | |
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42 | // get cluster and local pointer on reference process |
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43 | cxy_t ref_cxy = GET_CXY( ref_xp ); |
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44 | process_t * ref_ptr = (process_t *)GET_PTR( ref_xp ); |
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45 | |
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46 | // get extended pointer on root of mutex list |
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47 | xptr_t root_xp = XPTR( ref_cxy , &ref_ptr->mutex_root ); |
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48 | |
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49 | // scan reference process mutex list |
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50 | xptr_t iter_xp; |
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51 | xptr_t mutex_xp; |
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52 | cxy_t mutex_cxy; |
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53 | remote_mutex_t * mutex_ptr; |
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54 | intptr_t current; |
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55 | bool_t found = false; |
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56 | |
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57 | XLIST_FOREACH( root_xp , iter_xp ) |
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58 | { |
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59 | mutex_xp = XLIST_ELEMENT( iter_xp , remote_mutex_t , list ); |
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60 | mutex_cxy = GET_CXY( mutex_xp ); |
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61 | mutex_ptr = (remote_mutex_t *)GET_PTR( mutex_xp ); |
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62 | current = (intptr_t)hal_remote_lpt( XPTR( mutex_cxy , &mutex_ptr->ident ) ); |
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63 | if( ident == current ) |
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64 | { |
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65 | found = true; |
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66 | break; |
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67 | } |
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68 | } |
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69 | |
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70 | if( found == false ) return XPTR_NULL; |
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71 | else return mutex_xp; |
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72 | |
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73 | } // end remote_mutex_from_ident() |
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74 | |
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75 | ///////////////////////////////////////////// |
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76 | error_t remote_mutex_create( intptr_t ident ) |
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77 | { |
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78 | xptr_t mutex_xp; |
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79 | remote_mutex_t * mutex_ptr; |
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80 | |
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81 | // get pointer on local process descriptor |
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82 | process_t * process = CURRENT_THREAD->process; |
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83 | |
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84 | // get extended pointer on reference process |
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85 | xptr_t ref_xp = process->ref_xp; |
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86 | |
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87 | // get reference process cluster and local pointer |
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88 | cxy_t ref_cxy = GET_CXY( ref_xp ); |
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89 | process_t * ref_ptr = (process_t *)GET_PTR( ref_xp ); |
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90 | |
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91 | // allocate memory for barrier descriptor |
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92 | if( ref_cxy == local_cxy ) // local cluster is the reference |
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93 | { |
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94 | kmem_req_t req; |
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95 | req.type = KMEM_MUTEX; |
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96 | req.flags = AF_ZERO; |
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97 | mutex_ptr = kmem_alloc( &req ); |
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98 | mutex_xp = XPTR( local_cxy , mutex_ptr ); |
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99 | } |
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100 | else // reference is remote |
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101 | { |
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102 | rpc_kcm_alloc_client( ref_cxy , KMEM_MUTEX , &mutex_xp ); |
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103 | mutex_ptr = (remote_mutex_t *)GET_PTR( mutex_xp ); |
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104 | } |
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105 | |
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106 | if( mutex_ptr == NULL ) return ENOMEM; |
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107 | |
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108 | // initialise mutex |
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109 | hal_remote_sw ( XPTR( ref_cxy , &mutex_ptr->value ) , 0 ); |
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110 | hal_remote_spt( XPTR( ref_cxy , &mutex_ptr->ident ) , (void *)ident ); |
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111 | hal_remote_swd( XPTR( ref_cxy , &mutex_ptr->owner ) , XPTR_NULL ); |
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112 | |
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113 | xlist_entry_init( XPTR( ref_cxy , &mutex_ptr->list ) ); |
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114 | xlist_root_init( XPTR( ref_cxy , &mutex_ptr->root ) ); |
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115 | remote_spinlock_init( XPTR( ref_cxy , &mutex_ptr->lock ) ); |
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116 | |
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117 | // register mutex in reference process xlist |
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118 | xptr_t root_xp = XPTR( ref_cxy , &ref_ptr->mutex_root ); |
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119 | xptr_t xp_list = XPTR( ref_cxy , &mutex_ptr->list ); |
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120 | |
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121 | remote_spinlock_lock( XPTR( ref_cxy , &ref_ptr->sync_lock ) ); |
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122 | xlist_add_first( root_xp , xp_list ); |
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123 | remote_spinlock_unlock( XPTR( ref_cxy , &ref_ptr->sync_lock ) ); |
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124 | |
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125 | return 0; |
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126 | |
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127 | } // end remote_mutex_create() |
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128 | |
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129 | //////////////////////////////////////////// |
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130 | void remote_mutex_destroy( xptr_t mutex_xp ) |
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131 | { |
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132 | // get pointer on local process descriptor |
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133 | process_t * process = CURRENT_THREAD->process; |
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134 | |
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135 | // get extended pointer on reference process |
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136 | xptr_t ref_xp = process->ref_xp; |
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137 | |
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138 | // get reference process cluster and local pointer |
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139 | cxy_t ref_cxy = GET_CXY( ref_xp ); |
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140 | process_t * ref_ptr = (process_t *)GET_PTR( ref_xp ); |
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141 | |
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142 | // get mutex cluster and local pointer |
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143 | cxy_t mutex_cxy = GET_CXY( mutex_xp ); |
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144 | remote_mutex_t * mutex_ptr = (remote_mutex_t *)GET_PTR( mutex_xp ); |
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145 | |
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146 | // remove mutex from reference process xlist |
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147 | remote_spinlock_lock( XPTR( ref_cxy , &ref_ptr->sync_lock ) ); |
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148 | xlist_unlink( XPTR( mutex_cxy , &mutex_ptr->list ) ); |
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149 | remote_spinlock_unlock( XPTR( ref_cxy , &ref_ptr->sync_lock ) ); |
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150 | |
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151 | // release memory allocated for mutexaphore descriptor |
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152 | if( mutex_cxy == local_cxy ) // reference is local |
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153 | { |
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154 | kmem_req_t req; |
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155 | req.type = KMEM_MUTEX; |
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156 | req.ptr = mutex_ptr; |
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157 | kmem_free( &req ); |
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158 | } |
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159 | else // reference is remote |
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160 | { |
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161 | rpc_kcm_free_client( mutex_cxy , mutex_ptr , KMEM_BARRIER ); |
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162 | } |
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163 | |
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164 | } // end remote_mutex_destroy() |
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165 | |
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166 | ///////////////////////////////////////// |
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167 | void remote_mutex_lock( xptr_t mutex_xp ) |
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168 | { |
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169 | bool_t success; |
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170 | reg_t irq_state; |
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171 | |
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172 | // get cluster and local pointer on remote mutex |
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173 | remote_mutex_t * mutex_ptr = (remote_mutex_t *)GET_PTR( mutex_xp ); |
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174 | cxy_t mutex_cxy = GET_CXY( mutex_xp ); |
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175 | |
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176 | // get cluster and local pointer on calling thread |
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177 | cxy_t thread_cxy = local_cxy; |
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178 | thread_t * thread_ptr = CURRENT_THREAD; |
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179 | |
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180 | // get extended pointers on mutex value |
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181 | xptr_t value_xp = XPTR( mutex_cxy , &mutex_ptr->value ); |
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182 | |
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183 | // Try to take the mutex |
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184 | success = hal_remote_atomic_cas( value_xp , 0 , 1 ); |
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185 | |
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186 | if( success ) // take the lock |
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187 | { |
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188 | // register calling thread as mutex owner |
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189 | xptr_t owner_xp = XPTR( mutex_cxy , &mutex_ptr->owner ); |
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190 | hal_remote_swd( owner_xp , XPTR( thread_cxy , thread_ptr ) ); |
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191 | |
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192 | // increment calling thread remote_locks |
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193 | hal_remote_atomic_add( XPTR( thread_cxy , &thread_ptr->remote_locks ) , 1 ); |
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194 | } |
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195 | else // deschedule and register calling thread in queue |
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196 | { |
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197 | // disable interrupts |
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198 | hal_disable_irq( &irq_state ); |
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199 | |
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200 | // register calling thread in mutex waiting queue |
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201 | xptr_t root_xp = XPTR( mutex_cxy , &mutex_ptr->root ); |
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202 | xptr_t entry_xp = XPTR( thread_cxy , &thread_ptr->wait_list ); |
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203 | |
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204 | remote_spinlock_lock( XPTR( mutex_cxy , &mutex_ptr->lock ) ); |
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205 | xlist_add_last( root_xp , entry_xp ); |
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206 | remote_spinlock_unlock( XPTR( mutex_cxy , &mutex_ptr->lock ) ); |
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207 | |
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208 | // block & deschedule the calling thread |
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209 | thread_block( thread_ptr , THREAD_BLOCKED_USERSYNC ); |
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210 | sched_yield("blocked on mutex"); |
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211 | |
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212 | // restore interrupts |
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213 | hal_restore_irq( irq_state ); |
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214 | } |
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215 | |
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216 | hal_fence(); |
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217 | |
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218 | } // end remote_mutex_lock() |
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219 | |
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220 | /////////////////////////////////////////// |
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221 | void remote_mutex_unlock( xptr_t mutex_xp ) |
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222 | { |
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223 | reg_t irq_state; |
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224 | |
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225 | // get cluster and local pointer on remote mutex |
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226 | remote_mutex_t * mutex_ptr = (remote_mutex_t *)GET_PTR( mutex_xp ); |
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227 | cxy_t mutex_cxy = GET_CXY( mutex_xp ); |
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228 | |
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229 | // get cluster and local pointer on calling thread |
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230 | cxy_t thread_cxy = local_cxy; |
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231 | thread_t * thread_ptr = CURRENT_THREAD; |
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232 | |
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233 | // get extended pointers on mutex value, root, lock & owner fields |
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234 | xptr_t value_xp = XPTR( mutex_cxy , &mutex_ptr->value ); |
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235 | xptr_t owner_xp = XPTR( mutex_cxy , &mutex_ptr->owner ); |
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236 | xptr_t root_xp = XPTR( mutex_cxy , &mutex_ptr->root ); |
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237 | |
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238 | // disable interrupts |
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239 | hal_disable_irq( &irq_state ); |
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240 | |
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241 | // unregister owner thread, |
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242 | hal_remote_swd( owner_xp , XPTR_NULL ); |
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243 | |
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244 | // decrement calling thread remote_locks |
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245 | hal_remote_atomic_add( XPTR( thread_cxy , &thread_ptr->remote_locks ) , -1 ); |
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246 | |
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247 | // activate first waiting thread if required |
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248 | if( xlist_is_empty( root_xp ) == false ) // one waiiting thread |
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249 | { |
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250 | // get extended pointer on first waiting thread |
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251 | xptr_t thread_xp = XLIST_FIRST_ELEMENT( root_xp , thread_t , wait_list ); |
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252 | |
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253 | // remove first waiting thread from queue |
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254 | remote_spinlock_lock( XPTR( mutex_cxy , &mutex_ptr->lock ) ); |
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255 | xlist_unlink( XPTR( mutex_cxy , &mutex_ptr->list ) ); |
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256 | remote_spinlock_unlock( XPTR( mutex_cxy , &mutex_ptr->lock ) ); |
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257 | |
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258 | // unblock first waiting thread |
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259 | thread_unblock( thread_xp , THREAD_BLOCKED_USERSYNC ); |
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260 | } |
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261 | else // no waiting thread |
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262 | { |
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263 | // release mutex |
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264 | hal_remote_sw( value_xp , 0 ); |
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265 | } |
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266 | |
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267 | // restore interrupts |
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268 | hal_restore_irq( irq_state ); |
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269 | |
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270 | } // end remote_mutex_unlock() |
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271 | |
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