1 | /* |
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2 | * remote_sem.c - Kernel function implementing the semaphore related syscalls. |
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3 | * |
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4 | * Author 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_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_vaddr( intptr_t vaddr ) |
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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 = (process_t *)GET_PTR( ref_xp ); |
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46 | |
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47 | // get extended pointer on root of semaphores list |
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48 | xptr_t root_xp = XPTR( ref_cxy , &ref_ptr->sem_root ); |
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49 | |
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50 | // scan reference process semaphores list |
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51 | xptr_t iter_xp; |
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52 | xptr_t sem_xp; |
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53 | cxy_t sem_cxy; |
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54 | remote_sem_t * sem_ptr; |
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55 | intptr_t ident; |
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56 | bool_t found = false; |
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57 | |
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58 | XLIST_FOREACH( root_xp , iter_xp ) |
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59 | { |
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60 | sem_xp = XLIST_ELEMENT( iter_xp , remote_sem_t , list ); |
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61 | sem_cxy = GET_CXY( sem_xp ); |
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62 | sem_ptr = (remote_sem_t *)GET_PTR( sem_xp ); |
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63 | ident = (intptr_t)hal_remote_lpt( XPTR( sem_cxy , &sem_ptr->ident ) ); |
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64 | if( ident == vaddr ) |
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65 | { |
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66 | found = true; |
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67 | break; |
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68 | } |
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69 | } |
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70 | |
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71 | if( found == false ) return XPTR_NULL; |
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72 | else return sem_xp; |
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73 | |
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74 | } // end remote_sem_from_vaddr() |
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75 | |
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76 | /////////////////////////////////////////// |
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77 | error_t remote_sem_create( intptr_t vaddr, |
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78 | uint32_t value, |
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79 | xptr_t sem_xp_xp ) |
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80 | { |
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81 | remote_sem_t * sem_ptr; |
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82 | xptr_t sem_xp; |
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83 | |
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84 | // get pointer on local process descriptor |
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85 | process_t * process = CURRENT_THREAD->process; |
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86 | |
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87 | // get extended pointer on reference process |
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88 | xptr_t ref_xp = process->ref_xp; |
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89 | |
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90 | // get reference process cluster and local pointer |
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91 | cxy_t ref_cxy = GET_CXY( ref_xp ); |
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92 | process_t * ref_ptr = (process_t *)GET_PTR( ref_xp ); |
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93 | |
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94 | // allocate memory for new semaphore in reference cluster |
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95 | if( ref_cxy == local_cxy ) // local cluster is the reference |
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96 | { |
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97 | kmem_req_t req; |
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98 | req.type = KMEM_SEM; |
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99 | req.flags = AF_ZERO; |
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100 | sem_ptr = kmem_alloc( &req ); |
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101 | sem_xp = XPTR( local_cxy , sem_ptr ); |
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102 | } |
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103 | else // reference is remote |
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104 | { |
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105 | rpc_kcm_alloc_client( ref_cxy , KMEM_SEM , &sem_xp ); |
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106 | sem_ptr = GET_PTR( sem_xp ); |
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107 | } |
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108 | |
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109 | if( sem_xp == XPTR_NULL ) return -1; |
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110 | |
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111 | // initialise semaphore |
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112 | hal_remote_sw ( XPTR( ref_cxy , &sem_ptr->count ) , value ); |
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113 | hal_remote_spt( XPTR( ref_cxy , &sem_ptr->ident ) , (void *)vaddr ); |
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114 | remote_spinlock_init( XPTR( ref_cxy , &sem_ptr->lock ) ); |
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115 | xlist_root_init( XPTR( ref_cxy , &sem_ptr->root ) ); |
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116 | xlist_entry_init( XPTR( ref_cxy , &sem_ptr->list ) ); |
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117 | |
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118 | // register semaphore in reference process xlist |
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119 | xptr_t root_xp = XPTR( ref_cxy , &ref_ptr->sem_root ); |
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120 | xptr_t xp_list = XPTR( ref_cxy , &sem_ptr->list ); |
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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 | // write extended pointer on semaphore in calling thread buffer |
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126 | hal_remote_swd( sem_xp_xp , sem_xp ); |
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127 | |
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128 | return 0; |
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129 | |
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130 | } // en remote_sem_create() |
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131 | |
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132 | //////////////////////////////////////// |
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133 | void remote_sem_destroy( xptr_t sem_xp ) |
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134 | { |
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135 | // get pointer on local process descriptor |
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136 | process_t * process = CURRENT_THREAD->process; |
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137 | |
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138 | // get extended pointer on reference process |
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139 | xptr_t ref_xp = process->ref_xp; |
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140 | |
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141 | // get reference process cluster and local pointer |
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142 | cxy_t ref_cxy = GET_CXY( ref_xp ); |
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143 | process_t * ref_ptr = GET_PTR( ref_xp ); |
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144 | |
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145 | // get semaphore cluster and local pointer |
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146 | cxy_t sem_cxy = GET_CXY( sem_xp ); |
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147 | remote_sem_t * sem_ptr = (remote_sem_t *)GET_PTR( sem_xp ); |
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148 | |
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149 | // get lock protecting semaphore |
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150 | remote_spinlock_lock( XPTR( sem_cxy , &sem_ptr->lock ) ); |
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151 | |
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152 | // get remote pointer on waiting queue root |
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153 | xptr_t root_xp = XPTR( sem_cxy , &sem_ptr->root ); |
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154 | |
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155 | if( !xlist_is_empty( root_xp ) ) // user error |
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156 | { |
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157 | printk("WARNING in %s for thread %x in process %x : " |
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158 | "destroy semaphore, but waiting threads queue not empty\n", |
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159 | __FUNCTION__ , CURRENT_THREAD->trdid , CURRENT_THREAD->process->pid ); |
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160 | } |
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161 | |
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162 | // reset semaphore count |
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163 | hal_remote_sw( XPTR( sem_cxy , &sem_ptr->count ) , 0 ); |
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164 | |
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165 | // remove semaphore from reference process xlist |
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166 | remote_spinlock_lock( XPTR( ref_cxy , &ref_ptr->sync_lock ) ); |
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167 | xlist_unlink( XPTR( sem_cxy , &sem_ptr->list ) ); |
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168 | remote_spinlock_unlock( XPTR( ref_cxy , &ref_ptr->sync_lock ) ); |
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169 | |
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170 | // release lock |
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171 | remote_spinlock_unlock( XPTR( sem_cxy , &sem_ptr->lock ) ); |
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172 | |
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173 | // release memory allocated for semaphore descriptor |
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174 | if( sem_cxy == local_cxy ) // reference is local |
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175 | { |
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176 | kmem_req_t req; |
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177 | req.type = KMEM_SEM; |
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178 | req.ptr = sem_ptr; |
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179 | kmem_free( &req ); |
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180 | } |
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181 | else // reference is remote |
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182 | { |
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183 | rpc_kcm_free_client( sem_cxy , sem_ptr , KMEM_SEM ); |
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184 | } |
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185 | |
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186 | } // end remote_sem_destroy() |
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187 | |
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188 | ///////////////////////////////////// |
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189 | void remote_sem_wait( xptr_t sem_xp ) |
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190 | { |
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191 | // get semaphore cluster and local pointer |
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192 | cxy_t sem_cxy = GET_CXY( sem_xp ); |
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193 | remote_sem_t * sem_ptr = GET_PTR( sem_xp ); |
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194 | |
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195 | // get lock protecting semaphore |
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196 | remote_spinlock_lock( XPTR( sem_cxy , &sem_ptr->lock ) ); |
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197 | |
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198 | // get semaphore current value |
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199 | uint32_t count = hal_remote_lw( XPTR( sem_cxy , &sem_ptr->count ) ); |
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200 | |
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201 | if( count > 0 ) // success |
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202 | { |
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203 | // decrement semaphore value |
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204 | hal_remote_sw( XPTR( sem_cxy , &sem_ptr->count ) , count - 1 ); |
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205 | |
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206 | // release lock |
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207 | remote_spinlock_unlock( XPTR( sem_cxy , &sem_ptr->lock ) ); |
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208 | } |
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209 | else // failure |
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210 | { |
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211 | thread_t * this = CURRENT_THREAD; |
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212 | |
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213 | // register thread in waiting queue |
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214 | xptr_t root_xp = XPTR( sem_cxy , &sem_ptr->root ); |
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215 | xptr_t list_xp = XPTR( local_cxy , &this->wait_list ); |
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216 | xlist_add_last( root_xp , list_xp ); |
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217 | |
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218 | // release lock |
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219 | remote_spinlock_unlock( XPTR( sem_cxy , &sem_ptr->lock ) ); |
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220 | |
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221 | // block and deschedule |
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222 | thread_block( XPTR( local_cxy , this ) , THREAD_BLOCKED_SEM ); |
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223 | sched_yield("blocked on semaphore"); |
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224 | } |
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225 | } // end remote_sem_wait() |
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226 | |
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227 | ///////////////////////////////////// |
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228 | void remote_sem_post( xptr_t sem_xp ) |
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229 | { |
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230 | // get semaphore cluster and local pointer |
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231 | cxy_t sem_cxy = GET_CXY( sem_xp ); |
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232 | remote_sem_t * sem_ptr = GET_PTR( sem_xp ); |
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233 | |
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234 | // get lock protecting semaphore |
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235 | remote_spinlock_lock( XPTR( sem_cxy , &sem_ptr->lock ) ); |
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236 | |
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237 | // get semaphore current value |
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238 | uint32_t count = hal_remote_lw( XPTR( sem_cxy , &sem_ptr->count ) ); |
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239 | |
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240 | // get remote pointer on waiting queue root |
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241 | xptr_t root_xp = XPTR( sem_cxy , &sem_ptr->root ); |
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242 | |
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243 | if( xlist_is_empty( root_xp ) ) // no waiting thread |
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244 | { |
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245 | // increment semaphore value |
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246 | hal_remote_sw( XPTR( sem_cxy , &sem_ptr->count ) , count + 1 ); |
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247 | } |
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248 | else |
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249 | { |
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250 | // get first waiting thread from queue |
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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 | // get thread cluster and local poiner |
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254 | cxy_t thread_cxy = GET_CXY( thread_xp ); |
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255 | thread_t * thread_ptr = GET_PTR( thread_xp ); |
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256 | |
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257 | // remove this thread from the waiting queue, and unblock it |
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258 | xlist_unlink( XPTR( thread_cxy , &thread_ptr->wait_list ) ); |
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259 | thread_unblock( thread_xp , THREAD_BLOCKED_SEM ); |
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260 | } |
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261 | |
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262 | // release lock |
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263 | remote_spinlock_unlock( XPTR( sem_cxy , &sem_ptr->lock ) ); |
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264 | |
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265 | } // end remote_sem_post() |
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266 | |
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267 | |
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268 | ////////////////////////////////////////////// |
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269 | void remote_sem_get_value( xptr_t sem_xp, |
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270 | uint32_t * data ) |
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271 | { |
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272 | // get semaphore cluster and local pointer |
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273 | cxy_t sem_cxy = GET_CXY( sem_xp ); |
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274 | remote_sem_t * sem_ptr = GET_PTR( sem_xp ); |
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275 | |
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276 | *data = hal_remote_lw( XPTR( sem_cxy , &sem_ptr->count ) ); |
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277 | |
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278 | } // end remote_sem_get_value() |
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279 | |
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280 | |
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