1 | /* |
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2 | * remote_sem.c - POSIX unnamed semaphore implementation. |
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3 | * |
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4 | * Author Alain Greiner (2016,2017,2018,2019) |
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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_kernel_types.h> |
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25 | #include <hal_remote.h> |
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26 | #include <thread.h> |
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27 | #include <kmem.h> |
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28 | #include <printk.h> |
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29 | #include <process.h> |
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30 | #include <vmm.h> |
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31 | #include <remote_sem.h> |
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32 | |
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33 | |
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34 | /////////////////////////////////////////////// |
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35 | xptr_t remote_sem_from_ident( intptr_t ident ) |
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36 | { |
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37 | // get pointer on local process_descriptor |
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38 | process_t * process = CURRENT_THREAD->process; |
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39 | |
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40 | // get extended pointer on reference process |
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41 | xptr_t ref_xp = process->ref_xp; |
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42 | |
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43 | // get cluster and local pointer on reference process |
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44 | cxy_t ref_cxy = GET_CXY( ref_xp ); |
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45 | process_t * ref_ptr = GET_PTR( ref_xp ); |
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46 | |
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47 | // get extended pointer on semaphores list |
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48 | xptr_t root_xp = XPTR( ref_cxy , &ref_ptr->sem_root ); |
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49 | xptr_t lock_xp = XPTR( ref_cxy , &ref_ptr->sync_lock ); |
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50 | |
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51 | // get lock protecting synchro lists |
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52 | remote_queuelock_acquire( lock_xp ); |
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53 | |
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54 | // scan reference process semaphores list |
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55 | xptr_t iter_xp; |
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56 | xptr_t sem_xp; |
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57 | cxy_t sem_cxy; |
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58 | remote_sem_t * sem_ptr; |
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59 | intptr_t current; |
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60 | bool_t found = false; |
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61 | |
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62 | XLIST_FOREACH( root_xp , iter_xp ) |
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63 | { |
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64 | sem_xp = XLIST_ELEMENT( iter_xp , remote_sem_t , list ); |
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65 | sem_cxy = GET_CXY( sem_xp ); |
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66 | sem_ptr = GET_PTR( sem_xp ); |
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67 | current = (intptr_t)hal_remote_lpt( XPTR( sem_cxy , &sem_ptr->ident ) ); |
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68 | |
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69 | if( current == ident ) |
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70 | { |
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71 | found = true; |
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72 | break; |
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73 | } |
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74 | } |
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75 | |
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76 | // relese lock protecting synchros lists |
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77 | remote_queuelock_release( lock_xp ); |
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78 | |
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79 | if( found == false ) return XPTR_NULL; |
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80 | else return sem_xp; |
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81 | |
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82 | } // end remote_sem_from_ident() |
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83 | |
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84 | /////////////////////////////////////////// |
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85 | error_t remote_sem_create( intptr_t vaddr, |
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86 | uint32_t value ) |
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87 | { |
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88 | kmem_req_t req; |
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89 | remote_sem_t * sem_ptr; |
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90 | |
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91 | // get pointer on local process descriptor |
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92 | process_t * process = CURRENT_THREAD->process; |
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93 | |
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94 | // get extended pointer on reference process |
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95 | xptr_t ref_xp = process->ref_xp; |
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96 | |
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97 | // get reference process cluster and local pointer |
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98 | cxy_t ref_cxy = GET_CXY( ref_xp ); |
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99 | process_t * ref_ptr = (process_t *)GET_PTR( ref_xp ); |
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100 | |
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101 | // allocate memory for new semaphore in reference cluster |
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102 | req.type = KMEM_KCM; |
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103 | req.order = bits_log2( sizeof(remote_sem_t) ); |
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104 | req.flags = AF_ZERO | AF_KERNEL; |
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105 | sem_ptr = kmem_remote_alloc( ref_cxy, &req ); |
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106 | |
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107 | if( sem_ptr == NULL ) |
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108 | { |
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109 | printk("\n[ERROR] in %s : cannot create semaphore\n", __FUNCTION__ ); |
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110 | return -1; |
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111 | } |
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112 | |
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113 | // initialise semaphore |
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114 | hal_remote_s32 ( XPTR( ref_cxy , &sem_ptr->count ) , value ); |
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115 | hal_remote_spt( XPTR( ref_cxy , &sem_ptr->ident ) , (void *)vaddr ); |
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116 | xlist_root_init( XPTR( ref_cxy , &sem_ptr->root ) ); |
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117 | xlist_entry_init( XPTR( ref_cxy , &sem_ptr->list ) ); |
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118 | remote_busylock_init( XPTR( ref_cxy , &sem_ptr->lock ), LOCK_SEM_STATE ); |
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119 | |
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120 | xptr_t root_xp = XPTR( ref_cxy , &ref_ptr->sem_root ); |
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121 | xptr_t list_xp = XPTR( ref_cxy , &sem_ptr->list ); |
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122 | |
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123 | // get lock protecting user synchro lists |
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124 | remote_queuelock_acquire( XPTR( ref_cxy , &ref_ptr->sync_lock ) ); |
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125 | |
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126 | // register semaphore in reference process list of semaphores |
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127 | xlist_add_first( root_xp , list_xp ); |
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128 | |
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129 | // release lock protecting user synchro lists |
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130 | remote_queuelock_release( XPTR( ref_cxy , &ref_ptr->sync_lock ) ); |
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131 | |
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132 | #if DEBUG_SEM |
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133 | thread_t * this = CURRENT_THREAD; |
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134 | if( (uint32_t)hal_get_cycles() > DEBUG_SEM ) |
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135 | printk("\n[DBG] %s : thread %x in process %x INITIALIZE sem(%x,%x) / value %d\n", |
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136 | __FUNCTION__, this->trdid, this->process->pid, local_cxy, sem_ptr, value ); |
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137 | #endif |
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138 | |
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139 | return 0; |
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140 | |
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141 | } // end remote_sem_create() |
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142 | |
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143 | //////////////////////////////////////// |
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144 | void remote_sem_destroy( xptr_t sem_xp ) |
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145 | { |
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146 | kmem_req_t req; |
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147 | |
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148 | // get pointer on local process descriptor |
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149 | process_t * process = CURRENT_THREAD->process; |
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150 | |
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151 | // get extended pointer on reference process |
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152 | xptr_t ref_xp = process->ref_xp; |
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153 | |
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154 | // get reference process cluster and local pointer |
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155 | cxy_t ref_cxy = GET_CXY( ref_xp ); |
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156 | process_t * ref_ptr = GET_PTR( ref_xp ); |
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157 | |
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158 | // get semaphore cluster and local pointer |
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159 | cxy_t sem_cxy = GET_CXY( sem_xp ); |
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160 | remote_sem_t * sem_ptr = GET_PTR( sem_xp ); |
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161 | |
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162 | // get remote pointer on waiting queue root |
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163 | xptr_t root_xp = XPTR( sem_cxy , &sem_ptr->root ); |
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164 | |
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165 | if( !xlist_is_empty( root_xp ) ) // user error |
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166 | { |
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167 | printk("WARNING in %s for thread %x in process %x : " |
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168 | "destroy semaphore, but waiting threads queue not empty\n", |
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169 | __FUNCTION__ , CURRENT_THREAD->trdid , CURRENT_THREAD->process->pid ); |
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170 | } |
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171 | |
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172 | // remove semaphore from reference process xlist |
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173 | remote_queuelock_acquire( XPTR( ref_cxy , &ref_ptr->sync_lock ) ); |
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174 | xlist_unlink( XPTR( sem_cxy , &sem_ptr->list ) ); |
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175 | remote_queuelock_release( XPTR( ref_cxy , &ref_ptr->sync_lock ) ); |
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176 | |
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177 | // release memory allocated for semaphore descriptor |
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178 | req.type = KMEM_KCM; |
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179 | req.ptr = sem_ptr; |
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180 | kmem_remote_free( sem_cxy , &req ); |
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181 | |
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182 | } // end remote_sem_destroy() |
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183 | |
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184 | ///////////////////////////////////// |
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185 | void remote_sem_wait( xptr_t sem_xp ) |
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186 | { |
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187 | thread_t * this = CURRENT_THREAD; |
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188 | |
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189 | // check calling thread can yield |
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190 | assert( __FUNCTION__, (this->busylocks == 0), |
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191 | "cannot yield : busylocks = %d\n", this->busylocks ); |
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192 | |
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193 | |
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194 | // get semaphore cluster and local pointer |
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195 | cxy_t sem_cxy = GET_CXY( sem_xp ); |
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196 | remote_sem_t * sem_ptr = GET_PTR( sem_xp ); |
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197 | |
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198 | // get extended pointers on sem fields |
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199 | xptr_t count_xp = XPTR( sem_cxy , &sem_ptr->count ); |
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200 | xptr_t root_xp = XPTR( sem_cxy , &sem_ptr->root ); |
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201 | xptr_t lock_xp = XPTR( sem_cxy , &sem_ptr->lock ); |
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202 | |
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203 | while( 1 ) |
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204 | { |
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205 | // get busylock protecting semaphore |
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206 | remote_busylock_acquire( lock_xp ); |
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207 | |
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208 | // get semaphore current value |
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209 | uint32_t count = hal_remote_l32( count_xp ); |
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210 | |
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211 | if( count > 0 ) // success |
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212 | { |
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213 | // decrement semaphore value |
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214 | hal_remote_s32( count_xp , count - 1 ); |
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215 | |
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216 | #if DEBUG_SEM |
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217 | if( (uint32_t)hal_get_cycles() > DEBUG_SEM ) |
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218 | printk("\n[DBG] %s : thread %x in process %x DECREMENT sem(%x,%x) / value %d\n", |
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219 | __FUNCTION__, this->trdid, this->process->pid, sem_cxy, sem_ptr, count-1 ); |
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220 | #endif |
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221 | // release busylock protecting semaphore |
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222 | remote_busylock_release( XPTR( sem_cxy , &sem_ptr->lock ) ); |
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223 | |
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224 | return; |
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225 | } |
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226 | else // failure |
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227 | { |
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228 | // get cluster and pointers on calling thread |
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229 | cxy_t caller_cxy = local_cxy; |
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230 | thread_t * caller_ptr = CURRENT_THREAD; |
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231 | xptr_t caller_xp = XPTR( caller_cxy , caller_ptr ); |
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232 | |
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233 | // block the calling thread |
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234 | thread_block( caller_xp , THREAD_BLOCKED_SEM ); |
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235 | |
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236 | // register calling thread in waiting queue |
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237 | xptr_t entry_xp = XPTR( caller_cxy , &caller_ptr->wait_xlist ); |
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238 | xlist_add_last( root_xp , entry_xp ); |
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239 | |
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240 | #if DEBUG_SEM |
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241 | if( (uint32_t)hal_get_cycles() > DEBUG_SEM ) |
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242 | printk("\n[DBG] %s : thread %x in process %x BLOCK on sem(%x,%x) / value %d\n", |
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243 | __FUNCTION__, this->trdid, this->process->pid, sem_cxy, sem_ptr, count ); |
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244 | #endif |
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245 | // release busylock protecting semaphore |
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246 | remote_busylock_release( XPTR( sem_cxy , &sem_ptr->lock ) ); |
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247 | |
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248 | // deschedule calling thread |
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249 | sched_yield("blocked on semaphore"); |
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250 | } |
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251 | } |
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252 | } // end remote_sem_wait() |
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253 | |
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254 | ///////////////////////////////////// |
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255 | void remote_sem_post( xptr_t sem_xp ) |
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256 | { |
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257 | // memory barrier before sem release |
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258 | hal_fence(); |
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259 | |
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260 | // get semaphore cluster and local pointer |
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261 | cxy_t sem_cxy = GET_CXY( sem_xp ); |
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262 | remote_sem_t * sem_ptr = GET_PTR( sem_xp ); |
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263 | |
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264 | // get extended pointers on sem fields |
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265 | xptr_t count_xp = XPTR( sem_cxy , &sem_ptr->count ); |
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266 | xptr_t root_xp = XPTR( sem_cxy , &sem_ptr->root ); |
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267 | xptr_t lock_xp = XPTR( sem_cxy , &sem_ptr->lock ); |
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268 | |
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269 | // get busylock protecting semaphore |
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270 | remote_busylock_acquire( lock_xp ); |
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271 | |
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272 | // increment semaphore value |
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273 | hal_remote_atomic_add( count_xp , 1 ); |
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274 | |
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275 | #if DEBUG_SEM |
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276 | uint32_t count = hal_remote_l32( count_xp ); |
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277 | thread_t * this = CURRENT_THREAD; |
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278 | if( (uint32_t)hal_get_cycles() > DEBUG_SEM ) |
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279 | printk("\n[DBG] %s : thread %x in process %x INCREMENT sem(%x,%x) / value %d\n", |
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280 | __FUNCTION__, this->trdid, this->process->pid, sem_cxy, sem_ptr, count ); |
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281 | #endif |
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282 | |
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283 | // scan waiting queue to unblock all waiting threads |
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284 | while( xlist_is_empty( root_xp ) == false ) // waiting queue non empty |
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285 | { |
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286 | // get first waiting thread from queue |
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287 | xptr_t thread_xp = XLIST_FIRST( root_xp , thread_t , wait_xlist ); |
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288 | cxy_t thread_cxy = GET_CXY( thread_xp ); |
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289 | thread_t * thread_ptr = GET_PTR( thread_xp ); |
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290 | |
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291 | // remove this thread from the waiting queue |
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292 | xlist_unlink( XPTR( thread_cxy , &thread_ptr->wait_xlist ) ); |
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293 | |
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294 | // unblock this waiting thread |
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295 | thread_unblock( thread_xp , THREAD_BLOCKED_SEM ); |
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296 | |
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297 | #if DEBUG_SEM |
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298 | if( (uint32_t)hal_get_cycles() > DEBUG_SEM ) |
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299 | { |
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300 | trdid_t trdid = hal_remote_l32( XPTR( thread_cxy , &thread_ptr->trdid ) ); |
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301 | process_t * process = hal_remote_lpt( XPTR( thread_cxy , &thread_ptr->process ) ); |
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302 | pid_t pid = hal_remote_l32( XPTR( thread_cxy , &process->pid ) ); |
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303 | printk("\n[DBG] %s : thread %x in process %x UNBLOCK thread %x in process %x / sem(%x,%x)\n", |
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304 | __FUNCTION__, this->trdid, this->process->pid, trdid, pid, sem_cxy, sem_ptr ); |
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305 | } |
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306 | #endif |
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307 | |
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308 | } |
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309 | |
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310 | // release busylock protecting the semaphore |
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311 | remote_busylock_release( XPTR( sem_cxy , &sem_ptr->lock ) ); |
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312 | |
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313 | } // end remote_sem_post() |
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314 | |
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315 | |
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316 | ////////////////////////////////////////////// |
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317 | void remote_sem_get_value( xptr_t sem_xp, |
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318 | uint32_t * data ) |
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319 | { |
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320 | // get semaphore cluster and local pointer |
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321 | cxy_t sem_cxy = GET_CXY( sem_xp ); |
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322 | remote_sem_t * sem_ptr = GET_PTR( sem_xp ); |
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323 | |
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324 | *data = hal_remote_l32( XPTR( sem_cxy , &sem_ptr->count ) ); |
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325 | |
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326 | } // end remote_sem_get_value() |
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327 | |
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328 | |
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