1 | // -*- Mode: CFA -*- |
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2 | // |
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3 | // Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo |
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4 | // |
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5 | // The contents of this file are covered under the licence agreement in the |
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6 | // file "LICENCE" distributed with Cforall. |
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7 | // |
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8 | // kernel.c -- |
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9 | // |
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10 | // Author : Thierry Delisle |
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11 | // Created On : Tue Jan 17 12:27:26 2016 |
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12 | // Last Modified By : Thierry Delisle |
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13 | // Last Modified On : -- |
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14 | // Update Count : 0 |
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15 | // |
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16 | |
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17 | //Header |
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18 | #include "kernel" |
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19 | |
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20 | //C Includes |
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21 | #include <stddef.h> |
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22 | extern "C" { |
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23 | #include <sys/resource.h> |
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24 | } |
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25 | |
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26 | //CFA Includes |
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27 | #include "libhdr.h" |
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28 | #include "threads" |
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29 | |
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30 | //Private includes |
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31 | #define __CFA_INVOKE_PRIVATE__ |
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32 | #include "invoke.h" |
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33 | |
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34 | //----------------------------------------------------------------------------- |
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35 | // Kernel storage |
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36 | struct processorCtx_t { |
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37 | processor * proc; |
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38 | coroutine c; |
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39 | }; |
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40 | |
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41 | DECL_COROUTINE(processorCtx_t) |
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42 | |
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43 | #define KERNEL_STORAGE(T,X) static char X##_storage[sizeof(T)] |
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44 | |
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45 | KERNEL_STORAGE(processorCtx_t, systemProcessorCtx); |
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46 | KERNEL_STORAGE(cluster, systemCluster); |
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47 | KERNEL_STORAGE(processor, systemProcessor); |
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48 | KERNEL_STORAGE(thread, mainThread); |
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49 | KERNEL_STORAGE(machine_context_t, mainThread_context); |
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50 | |
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51 | cluster * systemCluster; |
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52 | processor * systemProcessor; |
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53 | thread * mainThread; |
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54 | |
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55 | void kernel_startup(void) __attribute__((constructor(101))); |
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56 | void kernel_shutdown(void) __attribute__((destructor(101))); |
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57 | |
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58 | //----------------------------------------------------------------------------- |
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59 | // Global state |
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60 | |
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61 | thread_local processor * this_processor; |
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62 | |
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63 | processor * get_this_processor() { |
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64 | return this_processor; |
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65 | } |
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66 | |
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67 | coroutine * this_coroutine(void) { |
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68 | return this_processor->current_coroutine; |
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69 | } |
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70 | |
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71 | thread * this_thread(void) { |
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72 | return this_processor->current_thread; |
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73 | } |
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74 | |
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75 | //----------------------------------------------------------------------------- |
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76 | // Main thread construction |
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77 | struct current_stack_info_t { |
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78 | machine_context_t ctx; |
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79 | unsigned int size; // size of stack |
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80 | void *base; // base of stack |
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81 | void *storage; // pointer to stack |
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82 | void *limit; // stack grows towards stack limit |
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83 | void *context; // address of cfa_context_t |
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84 | void *top; // address of top of storage |
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85 | }; |
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86 | |
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87 | void ?{}( current_stack_info_t * this ) { |
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88 | CtxGet( &this->ctx ); |
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89 | this->base = this->ctx.FP; |
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90 | this->storage = this->ctx.SP; |
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91 | |
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92 | rlimit r; |
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93 | int ret = getrlimit( RLIMIT_STACK, &r); |
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94 | this->size = r.rlim_cur; |
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95 | |
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96 | this->limit = (void *)(((intptr_t)this->base) - this->size); |
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97 | this->context = &mainThread_context_storage; |
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98 | this->top = this->base; |
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99 | } |
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100 | |
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101 | void ?{}( coStack_t * this, current_stack_info_t * info) { |
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102 | this->size = info->size; |
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103 | this->storage = info->storage; |
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104 | this->limit = info->limit; |
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105 | this->base = info->base; |
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106 | this->context = info->context; |
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107 | this->top = info->top; |
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108 | this->userStack = true; |
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109 | } |
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110 | |
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111 | void ?{}( coroutine * this, current_stack_info_t * info) { |
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112 | (&this->stack){ info }; |
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113 | this->name = "Main Thread"; |
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114 | this->errno_ = 0; |
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115 | this->state = Inactive; |
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116 | this->notHalted = true; |
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117 | } |
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118 | |
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119 | void ?{}( thread * this, current_stack_info_t * info) { |
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120 | (&this->c){ info }; |
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121 | } |
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122 | |
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123 | //----------------------------------------------------------------------------- |
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124 | // Processor coroutine |
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125 | void ?{}(processorCtx_t * this, processor * proc) { |
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126 | (&this->c){}; |
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127 | this->proc = proc; |
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128 | proc->ctx = this; |
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129 | } |
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130 | |
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131 | void ?{}(processorCtx_t * this, processor * proc, current_stack_info_t * info) { |
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132 | (&this->c){ info }; |
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133 | this->proc = proc; |
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134 | proc->ctx = this; |
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135 | } |
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136 | |
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137 | void start(processor * this); |
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138 | |
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139 | void ?{}(processor * this) { |
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140 | this{ systemCluster }; |
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141 | } |
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142 | |
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143 | void ?{}(processor * this, cluster * cltr) { |
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144 | this->cltr = cltr; |
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145 | this->current_coroutine = NULL; |
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146 | this->current_thread = NULL; |
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147 | (&this->lock){}; |
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148 | this->terminated = false; |
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149 | |
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150 | start( this ); |
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151 | } |
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152 | |
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153 | void ?{}(processor * this, cluster * cltr, processorCtx_t * ctx) { |
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154 | this->cltr = cltr; |
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155 | this->current_coroutine = NULL; |
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156 | this->current_thread = NULL; |
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157 | (&this->lock){}; |
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158 | this->terminated = false; |
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159 | |
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160 | this->ctx = ctx; |
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161 | LIB_DEBUG_PRINTF("Kernel : constructing processor context %p\n", ctx); |
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162 | ctx{ this }; |
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163 | } |
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164 | |
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165 | void ^?{}(processor * this) { |
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166 | if( ! this->terminated ) { |
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167 | LIB_DEBUG_PRINTF("Kernel : core %p signaling termination\n", this); |
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168 | this->terminated = true; |
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169 | lock( &this->lock ); |
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170 | } |
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171 | } |
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172 | |
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173 | void ?{}(cluster * this) { |
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174 | ( &this->ready_queue ){}; |
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175 | pthread_spin_init( &this->lock, PTHREAD_PROCESS_PRIVATE ); |
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176 | } |
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177 | |
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178 | void ^?{}(cluster * this) { |
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179 | pthread_spin_destroy( &this->lock ); |
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180 | } |
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181 | |
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182 | //----------------------------------------------------------------------------- |
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183 | // Processor running routines |
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184 | void main(processorCtx_t * ctx); |
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185 | thread * nextThread(cluster * this); |
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186 | void runThread(processor * this, thread * dst); |
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187 | void spin(processor * this, unsigned int * spin_count); |
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188 | |
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189 | void main(processorCtx_t * ctx) { |
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190 | processor * this = ctx->proc; |
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191 | LIB_DEBUG_PRINTF("Kernel : core %p starting\n", this); |
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192 | |
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193 | thread * readyThread = NULL; |
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194 | for( unsigned int spin_count = 0; ! this->terminated; spin_count++ ) { |
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195 | |
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196 | readyThread = nextThread( this->cltr ); |
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197 | |
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198 | if(readyThread) { |
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199 | runThread(this, readyThread); |
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200 | spin_count = 0; |
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201 | } else { |
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202 | spin(this, &spin_count); |
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203 | } |
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204 | } |
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205 | |
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206 | LIB_DEBUG_PRINTF("Kernel : core %p unlocking thread\n", this); |
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207 | unlock( &this->lock ); |
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208 | LIB_DEBUG_PRINTF("Kernel : core %p terminated\n", this); |
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209 | } |
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210 | |
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211 | void runThread(processor * this, thread * dst) { |
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212 | coroutine * proc_ctx = get_coroutine(this->ctx); |
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213 | coroutine * thrd_ctx = get_coroutine(dst); |
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214 | thrd_ctx->last = proc_ctx; |
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215 | |
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216 | // context switch to specified coroutine |
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217 | // Which is now the current_coroutine |
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218 | // LIB_DEBUG_PRINTF("Kernel : switching to ctx %p (from %p, current %p)\n", thrd_ctx, proc_ctx, current_coroutine); |
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219 | this->current_thread = dst; |
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220 | this->current_coroutine = thrd_ctx; |
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221 | CtxSwitch( proc_ctx->stack.context, thrd_ctx->stack.context ); |
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222 | this->current_coroutine = proc_ctx; |
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223 | // LIB_DEBUG_PRINTF("Kernel : returned from ctx %p (to %p, current %p)\n", thrd_ctx, proc_ctx, current_coroutine); |
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224 | |
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225 | // when CtxSwitch returns we are back in the processor coroutine |
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226 | } |
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227 | |
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228 | void spin(processor * this, unsigned int * spin_count) { |
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229 | (*spin_count)++; |
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230 | } |
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231 | |
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232 | void * CtxInvokeProcessor(void * arg) { |
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233 | processor * proc = (processor *) arg; |
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234 | this_processor = proc; |
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235 | // SKULLDUGGERY: We want to create a context for the processor coroutine |
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236 | // which is needed for the 2-step context switch. However, there is no reason |
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237 | // to waste the perfectly valid stack create by pthread. |
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238 | current_stack_info_t info; |
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239 | machine_context_t ctx; |
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240 | info.context = &ctx; |
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241 | processorCtx_t proc_cor_storage = { proc, &info }; |
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242 | |
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243 | proc->current_coroutine = &proc->ctx->c; |
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244 | proc->current_thread = NULL; |
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245 | |
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246 | LIB_DEBUG_PRINTF("Kernel : core %p created (%p)\n", proc, proc->ctx); |
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247 | |
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248 | // LIB_DEBUG_PRINTF("Kernel : core base : %p \n", info.base ); |
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249 | // LIB_DEBUG_PRINTF("Kernel : core storage : %p \n", info.storage ); |
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250 | // LIB_DEBUG_PRINTF("Kernel : core size : %x \n", info.size ); |
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251 | // LIB_DEBUG_PRINTF("Kernel : core limit : %p \n", info.limit ); |
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252 | // LIB_DEBUG_PRINTF("Kernel : core context : %p \n", info.context ); |
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253 | // LIB_DEBUG_PRINTF("Kernel : core top : %p \n", info.top ); |
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254 | |
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255 | //We now have a proper context from which to schedule threads |
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256 | |
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257 | // SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't |
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258 | // resume it to start it like it normally would, it will just context switch |
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259 | // back to here. Instead directly call the main since we already are on the |
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260 | // appropriate stack. |
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261 | proc_cor_storage.c.state = Active; |
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262 | main( &proc_cor_storage ); |
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263 | proc_cor_storage.c.state = Halt; |
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264 | proc_cor_storage.c.notHalted = false; |
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265 | |
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266 | LIB_DEBUG_PRINTF("Kernel : core %p main ended (%p)\n", proc, proc->ctx); |
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267 | |
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268 | return NULL; |
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269 | } |
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270 | |
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271 | void start(processor * this) { |
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272 | LIB_DEBUG_PRINTF("Kernel : Starting core %p\n", this); |
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273 | |
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274 | pthread_attr_t attributes; |
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275 | pthread_attr_init( &attributes ); |
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276 | |
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277 | pthread_create( &this->kernel_thread, &attributes, CtxInvokeProcessor, (void*)this ); |
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278 | |
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279 | pthread_attr_destroy( &attributes ); |
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280 | |
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281 | LIB_DEBUG_PRINTF("Kernel : core %p started\n", this); |
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282 | } |
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283 | |
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284 | //----------------------------------------------------------------------------- |
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285 | // Scheduler routines |
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286 | void thread_schedule( thread * thrd ) { |
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287 | assertf( thrd->next == NULL, "Expected null got %p", thrd->next ); |
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288 | |
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289 | pthread_spinlock_guard guard = { &systemProcessor->cltr->lock }; |
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290 | append( &systemProcessor->cltr->ready_queue, thrd ); |
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291 | } |
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292 | |
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293 | thread * nextThread(cluster * this) { |
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294 | pthread_spinlock_guard guard = { &this->lock }; |
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295 | return pop_head( &this->ready_queue ); |
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296 | } |
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297 | |
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298 | //----------------------------------------------------------------------------- |
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299 | // Kernel boot procedures |
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300 | void kernel_startup(void) { |
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301 | |
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302 | // SKULLDUGGERY: the mainThread steals the process main thread |
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303 | // which will then be scheduled by the systemProcessor normally |
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304 | LIB_DEBUG_PRINTF("Kernel : Starting\n"); |
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305 | |
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306 | current_stack_info_t info; |
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307 | |
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308 | // LIB_DEBUG_PRINTF("Kernel : core base : %p \n", info.base ); |
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309 | // LIB_DEBUG_PRINTF("Kernel : core storage : %p \n", info.storage ); |
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310 | // LIB_DEBUG_PRINTF("Kernel : core size : %x \n", info.size ); |
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311 | // LIB_DEBUG_PRINTF("Kernel : core limit : %p \n", info.limit ); |
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312 | // LIB_DEBUG_PRINTF("Kernel : core context : %p \n", info.context ); |
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313 | // LIB_DEBUG_PRINTF("Kernel : core top : %p \n", info.top ); |
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314 | |
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315 | // Start by initializing the main thread |
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316 | mainThread = (thread *)&mainThread_storage; |
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317 | mainThread{ &info }; |
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318 | |
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319 | // Initialize the system cluster |
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320 | systemCluster = (cluster *)&systemCluster_storage; |
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321 | systemCluster{}; |
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322 | |
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323 | // Initialize the system processor and the system processor ctx |
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324 | // (the coroutine that contains the processing control flow) |
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325 | systemProcessor = (processor *)&systemProcessor_storage; |
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326 | systemProcessor{ systemCluster, (processorCtx_t *)&systemProcessorCtx_storage }; |
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327 | |
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328 | // Add the main thread to the ready queue |
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329 | // once resume is called on systemProcessor->ctx the mainThread needs to be scheduled like any normal thread |
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330 | thread_schedule(mainThread); |
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331 | |
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332 | //initialize the global state variables |
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333 | this_processor = systemProcessor; |
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334 | this_processor->current_thread = mainThread; |
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335 | this_processor->current_coroutine = &mainThread->c; |
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336 | |
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337 | // SKULLDUGGERY: Force a context switch to the system processor to set the main thread's context to the current UNIX |
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338 | // context. Hence, the main thread does not begin through CtxInvokeThread, like all other threads. The trick here is that |
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339 | // mainThread is on the ready queue when this call is made. |
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340 | resume(systemProcessor->ctx); |
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341 | |
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342 | |
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343 | |
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344 | // THE SYSTEM IS NOW COMPLETELY RUNNING |
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345 | |
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346 | |
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347 | |
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348 | LIB_DEBUG_PRINTF("Kernel : Started\n--------------------------------------------------\n\n"); |
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349 | } |
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350 | |
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351 | void kernel_shutdown(void) { |
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352 | LIB_DEBUG_PRINTF("\n--------------------------------------------------\nKernel : Shutting down\n"); |
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353 | |
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354 | // SKULLDUGGERY: Notify the systemProcessor it needs to terminates. |
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355 | // When its coroutine terminates, it return control to the mainThread |
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356 | // which is currently here |
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357 | systemProcessor->terminated = true; |
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358 | suspend(); |
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359 | |
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360 | // THE SYSTEM IS NOW COMPLETELY STOPPED |
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361 | |
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362 | // Destroy the system processor and its context in reverse order of construction |
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363 | // These were manually constructed so we need manually destroy them |
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364 | ^(systemProcessor->ctx){}; |
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365 | ^(systemProcessor){}; |
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366 | |
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367 | // Final step, destroy the main thread since it is no longer needed |
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368 | // Since we provided a stack to this taxk it will not destroy anything |
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369 | ^(mainThread){}; |
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370 | |
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371 | LIB_DEBUG_PRINTF("Kernel : Shutdown complete\n"); |
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372 | } |
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373 | |
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374 | //----------------------------------------------------------------------------- |
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375 | // Locks |
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376 | void ?{}( simple_lock * this ) { |
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377 | ( &this->blocked ){}; |
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378 | } |
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379 | |
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380 | void ^?{}( simple_lock * this ) { |
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381 | |
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382 | } |
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383 | |
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384 | void lock( simple_lock * this ) { |
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385 | { |
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386 | pthread_spinlock_guard guard = { &systemCluster->lock }; //HUGE TEMP HACK which only works if we have a single cluster and is stupid |
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387 | append( &this->blocked, this_thread() ); |
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388 | } |
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389 | suspend(); |
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390 | } |
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391 | |
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392 | void unlock( simple_lock * this ) { |
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393 | thread * it; |
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394 | while( it = pop_head( &this->blocked) ) { |
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395 | thread_schedule( it ); |
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396 | } |
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397 | } |
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398 | |
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399 | //----------------------------------------------------------------------------- |
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400 | // Queues |
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401 | void ?{}( simple_thread_list * this ) { |
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402 | this->head = NULL; |
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403 | this->tail = &this->head; |
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404 | } |
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405 | |
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406 | void append( simple_thread_list * this, thread * t ) { |
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407 | assert( t->next == NULL ); |
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408 | *this->tail = t; |
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409 | this->tail = &t->next; |
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410 | } |
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411 | |
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412 | thread * pop_head( simple_thread_list * this ) { |
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413 | thread * head = this->head; |
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414 | if( head ) { |
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415 | this->head = head->next; |
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416 | if( !head->next ) { |
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417 | this->tail = &this->head; |
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418 | } |
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419 | head->next = NULL; |
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420 | } |
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421 | |
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422 | return head; |
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423 | } |
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424 | // Local Variables: // |
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425 | // mode: c // |
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426 | // tab-width: 4 // |
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427 | // End: // |
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