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 2017 |
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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 | #include "libhdr.h" |
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18 | |
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19 | //C Includes |
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20 | #include <stddef.h> |
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21 | extern "C" { |
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22 | #include <stdio.h> |
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23 | #include <fenv.h> |
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24 | #include <sys/resource.h> |
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25 | #include <signal.h> |
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26 | #include <unistd.h> |
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27 | } |
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28 | |
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29 | //CFA Includes |
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30 | #include "kernel_private.h" |
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31 | #include "preemption.h" |
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32 | #include "startup.h" |
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33 | |
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34 | //Private includes |
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35 | #define __CFA_INVOKE_PRIVATE__ |
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36 | #include "invoke.h" |
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37 | |
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38 | //Start and stop routine for the kernel, declared first to make sure they run first |
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39 | void kernel_startup(void) __attribute__(( constructor( STARTUP_PRIORITY_KERNEL ) )); |
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40 | void kernel_shutdown(void) __attribute__(( destructor ( STARTUP_PRIORITY_KERNEL ) )); |
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41 | |
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42 | //----------------------------------------------------------------------------- |
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43 | // Kernel storage |
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44 | #define KERNEL_STORAGE(T,X) static char X##Storage[sizeof(T)] |
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45 | |
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46 | KERNEL_STORAGE(processorCtx_t, systemProcessorCtx); |
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47 | KERNEL_STORAGE(cluster, systemCluster); |
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48 | KERNEL_STORAGE(system_proc_t, systemProcessor); |
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49 | KERNEL_STORAGE(thread_desc, mainThread); |
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50 | KERNEL_STORAGE(machine_context_t, mainThreadCtx); |
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51 | |
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52 | cluster * systemCluster; |
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53 | system_proc_t * systemProcessor; |
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54 | thread_desc * mainThread; |
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55 | |
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56 | //----------------------------------------------------------------------------- |
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57 | // Global state |
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58 | |
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59 | volatile thread_local processor * this_processor; |
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60 | volatile thread_local coroutine_desc * this_coroutine; |
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61 | volatile thread_local thread_desc * this_thread; |
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62 | volatile thread_local bool preemption_in_progress = 0; |
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63 | volatile thread_local unsigned short disable_preempt_count = 1; |
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64 | |
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65 | //----------------------------------------------------------------------------- |
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66 | // Main thread construction |
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67 | struct current_stack_info_t { |
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68 | machine_context_t ctx; |
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69 | unsigned int size; // size of stack |
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70 | void *base; // base of stack |
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71 | void *storage; // pointer to stack |
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72 | void *limit; // stack grows towards stack limit |
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73 | void *context; // address of cfa_context_t |
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74 | void *top; // address of top of storage |
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75 | }; |
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76 | |
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77 | void ?{}( current_stack_info_t & this ) { |
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78 | CtxGet( this.ctx ); |
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79 | this.base = this.ctx.FP; |
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80 | this.storage = this.ctx.SP; |
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81 | |
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82 | rlimit r; |
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83 | getrlimit( RLIMIT_STACK, &r); |
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84 | this.size = r.rlim_cur; |
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85 | |
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86 | this.limit = (void *)(((intptr_t)this.base) - this.size); |
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87 | this.context = &mainThreadCtxStorage; |
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88 | this.top = this.base; |
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89 | } |
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90 | |
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91 | void ?{}( coStack_t & this, current_stack_info_t * info) { |
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92 | this.size = info->size; |
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93 | this.storage = info->storage; |
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94 | this.limit = info->limit; |
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95 | this.base = info->base; |
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96 | this.context = info->context; |
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97 | this.top = info->top; |
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98 | this.userStack = true; |
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99 | } |
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100 | |
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101 | void ?{}( coroutine_desc & this, current_stack_info_t * info) { |
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102 | (this.stack){ info }; |
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103 | this.name = "Main Thread"; |
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104 | this.errno_ = 0; |
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105 | this.state = Start; |
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106 | } |
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107 | |
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108 | void ?{}( thread_desc & this, current_stack_info_t * info) { |
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109 | (this.cor){ info }; |
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110 | } |
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111 | |
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112 | //----------------------------------------------------------------------------- |
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113 | // Processor coroutine |
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114 | void ?{}(processorCtx_t & this, processor * proc) { |
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115 | (this.__cor){ "Processor" }; |
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116 | this.proc = proc; |
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117 | proc->runner = &this; |
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118 | } |
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119 | |
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120 | void ?{}(processorCtx_t & this, processor * proc, current_stack_info_t * info) { |
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121 | (this.__cor){ info }; |
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122 | this.proc = proc; |
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123 | proc->runner = &this; |
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124 | } |
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125 | |
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126 | void ?{}(processor & this) { |
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127 | this{ systemCluster }; |
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128 | } |
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129 | |
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130 | void ?{}(processor & this, cluster * cltr) { |
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131 | this.cltr = cltr; |
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132 | (this.terminated){ 0 }; |
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133 | this.is_terminated = false; |
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134 | this.preemption_alarm = NULL; |
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135 | this.preemption = default_preemption(); |
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136 | this.pending_preemption = false; |
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137 | |
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138 | start( &this ); |
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139 | } |
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140 | |
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141 | void ?{}(processor & this, cluster * cltr, processorCtx_t * runner) { |
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142 | this.cltr = cltr; |
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143 | (this.terminated){ 0 }; |
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144 | this.is_terminated = false; |
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145 | this.preemption_alarm = NULL; |
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146 | this.preemption = default_preemption(); |
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147 | this.pending_preemption = false; |
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148 | this.kernel_thread = pthread_self(); |
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149 | |
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150 | this.runner = runner; |
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151 | LIB_DEBUG_PRINT_SAFE("Kernel : constructing system processor context %p\n", runner); |
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152 | (*runner){ &this }; |
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153 | } |
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154 | |
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155 | LIB_DEBUG_DO( bool validate( alarm_list_t * this ); ) |
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156 | |
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157 | void ?{}(system_proc_t & this, cluster * cltr, processorCtx_t * runner) { |
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158 | (this.alarms){}; |
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159 | (this.alarm_lock){}; |
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160 | this.pending_alarm = false; |
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161 | |
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162 | (this.proc){ cltr, runner }; |
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163 | |
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164 | verify( validate( &this.alarms ) ); |
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165 | } |
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166 | |
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167 | void ^?{}(processor & this) { |
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168 | if( ! this.is_terminated ) { |
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169 | LIB_DEBUG_PRINT_SAFE("Kernel : core %p signaling termination\n", &this); |
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170 | this.is_terminated = true; |
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171 | P( this.terminated ); |
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172 | pthread_join( this.kernel_thread, NULL ); |
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173 | } |
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174 | } |
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175 | |
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176 | void ?{}(cluster & this) { |
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177 | ( this.ready_queue ){}; |
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178 | ( this.lock ){}; |
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179 | } |
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180 | |
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181 | void ^?{}(cluster & this) { |
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182 | |
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183 | } |
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184 | |
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185 | //============================================================================================= |
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186 | // Kernel Scheduling logic |
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187 | //============================================================================================= |
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188 | //Main of the processor contexts |
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189 | void main(processorCtx_t * runner) { |
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190 | processor * this = runner->proc; |
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191 | |
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192 | LIB_DEBUG_PRINT_SAFE("Kernel : core %p starting\n", this); |
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193 | |
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194 | { |
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195 | // Setup preemption data |
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196 | preemption_scope scope = { this }; |
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197 | |
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198 | LIB_DEBUG_PRINT_SAFE("Kernel : core %p started\n", this); |
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199 | |
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200 | thread_desc * readyThread = NULL; |
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201 | for( unsigned int spin_count = 0; ! this->is_terminated; spin_count++ ) |
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202 | { |
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203 | readyThread = nextThread( this->cltr ); |
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204 | |
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205 | if(readyThread) |
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206 | { |
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207 | verify( disable_preempt_count > 0 ); |
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208 | |
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209 | runThread(this, readyThread); |
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210 | |
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211 | verify( disable_preempt_count > 0 ); |
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212 | |
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213 | //Some actions need to be taken from the kernel |
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214 | finishRunning(this); |
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215 | |
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216 | spin_count = 0; |
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217 | } |
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218 | else |
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219 | { |
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220 | spin(this, &spin_count); |
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221 | } |
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222 | } |
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223 | |
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224 | LIB_DEBUG_PRINT_SAFE("Kernel : core %p stopping\n", this); |
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225 | } |
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226 | |
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227 | V( &this->terminated ); |
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228 | |
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229 | LIB_DEBUG_PRINT_SAFE("Kernel : core %p terminated\n", this); |
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230 | } |
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231 | |
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232 | // runThread runs a thread by context switching |
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233 | // from the processor coroutine to the target thread |
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234 | void runThread(processor * this, thread_desc * dst) { |
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235 | coroutine_desc * proc_cor = get_coroutine(this->runner); |
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236 | coroutine_desc * thrd_cor = get_coroutine(dst); |
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237 | |
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238 | //Reset the terminating actions here |
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239 | this->finish.action_code = No_Action; |
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240 | |
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241 | //Update global state |
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242 | this_thread = dst; |
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243 | |
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244 | // Context Switch to the thread |
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245 | ThreadCtxSwitch(proc_cor, thrd_cor); |
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246 | // when ThreadCtxSwitch returns we are back in the processor coroutine |
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247 | } |
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248 | |
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249 | // Once a thread has finished running, some of |
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250 | // its final actions must be executed from the kernel |
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251 | void finishRunning(processor * this) { |
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252 | if( this->finish.action_code == Release ) { |
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253 | unlock( this->finish.lock ); |
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254 | } |
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255 | else if( this->finish.action_code == Schedule ) { |
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256 | ScheduleThread( this->finish.thrd ); |
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257 | } |
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258 | else if( this->finish.action_code == Release_Schedule ) { |
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259 | unlock( this->finish.lock ); |
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260 | ScheduleThread( this->finish.thrd ); |
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261 | } |
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262 | else if( this->finish.action_code == Release_Multi ) { |
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263 | for(int i = 0; i < this->finish.lock_count; i++) { |
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264 | unlock( this->finish.locks[i] ); |
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265 | } |
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266 | } |
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267 | else if( this->finish.action_code == Release_Multi_Schedule ) { |
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268 | for(int i = 0; i < this->finish.lock_count; i++) { |
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269 | unlock( this->finish.locks[i] ); |
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270 | } |
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271 | for(int i = 0; i < this->finish.thrd_count; i++) { |
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272 | ScheduleThread( this->finish.thrds[i] ); |
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273 | } |
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274 | } |
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275 | else { |
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276 | assert(this->finish.action_code == No_Action); |
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277 | } |
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278 | } |
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279 | |
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280 | // Handles spinning logic |
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281 | // TODO : find some strategy to put cores to sleep after some time |
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282 | void spin(processor * this, unsigned int * spin_count) { |
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283 | (*spin_count)++; |
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284 | } |
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285 | |
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286 | // Context invoker for processors |
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287 | // This is the entry point for processors (kernel threads) |
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288 | // It effectively constructs a coroutine by stealing the pthread stack |
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289 | void * CtxInvokeProcessor(void * arg) { |
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290 | processor * proc = (processor *) arg; |
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291 | this_processor = proc; |
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292 | this_coroutine = NULL; |
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293 | this_thread = NULL; |
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294 | disable_preempt_count = 1; |
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295 | // SKULLDUGGERY: We want to create a context for the processor coroutine |
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296 | // which is needed for the 2-step context switch. However, there is no reason |
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297 | // to waste the perfectly valid stack create by pthread. |
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298 | current_stack_info_t info; |
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299 | machine_context_t ctx; |
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300 | info.context = &ctx; |
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301 | processorCtx_t proc_cor_storage = { proc, &info }; |
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302 | |
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303 | LIB_DEBUG_PRINT_SAFE("Coroutine : created stack %p\n", proc_cor_storage.__cor.stack.base); |
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304 | |
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305 | //Set global state |
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306 | this_coroutine = &proc->runner->__cor; |
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307 | this_thread = NULL; |
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308 | |
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309 | //We now have a proper context from which to schedule threads |
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310 | LIB_DEBUG_PRINT_SAFE("Kernel : core %p created (%p, %p)\n", proc, proc->runner, &ctx); |
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311 | |
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312 | // SKULLDUGGERY: Since the coroutine doesn't have its own stack, we can't |
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313 | // resume it to start it like it normally would, it will just context switch |
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314 | // back to here. Instead directly call the main since we already are on the |
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315 | // appropriate stack. |
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316 | proc_cor_storage.__cor.state = Active; |
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317 | main( &proc_cor_storage ); |
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318 | proc_cor_storage.__cor.state = Halted; |
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319 | |
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320 | // Main routine of the core returned, the core is now fully terminated |
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321 | LIB_DEBUG_PRINT_SAFE("Kernel : core %p main ended (%p)\n", proc, proc->runner); |
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322 | |
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323 | return NULL; |
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324 | } |
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325 | |
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326 | void start(processor * this) { |
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327 | LIB_DEBUG_PRINT_SAFE("Kernel : Starting core %p\n", this); |
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328 | |
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329 | pthread_create( &this->kernel_thread, NULL, CtxInvokeProcessor, (void*)this ); |
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330 | |
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331 | LIB_DEBUG_PRINT_SAFE("Kernel : core %p started\n", this); |
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332 | } |
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333 | |
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334 | //----------------------------------------------------------------------------- |
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335 | // Scheduler routines |
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336 | void ScheduleThread( thread_desc * thrd ) { |
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337 | // if( !thrd ) return; |
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338 | assert( thrd ); |
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339 | assert( thrd->cor.state != Halted ); |
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340 | |
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341 | verify( disable_preempt_count > 0 ); |
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342 | |
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343 | verifyf( thrd->next == NULL, "Expected null got %p", thrd->next ); |
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344 | |
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345 | lock( &systemProcessor->proc.cltr->lock DEBUG_CTX2 ); |
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346 | append( &systemProcessor->proc.cltr->ready_queue, thrd ); |
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347 | unlock( &systemProcessor->proc.cltr->lock ); |
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348 | |
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349 | verify( disable_preempt_count > 0 ); |
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350 | } |
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351 | |
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352 | thread_desc * nextThread(cluster * this) { |
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353 | verify( disable_preempt_count > 0 ); |
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354 | lock( &this->lock DEBUG_CTX2 ); |
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355 | thread_desc * head = pop_head( &this->ready_queue ); |
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356 | unlock( &this->lock ); |
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357 | verify( disable_preempt_count > 0 ); |
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358 | return head; |
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359 | } |
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360 | |
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361 | void BlockInternal() { |
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362 | disable_interrupts(); |
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363 | verify( disable_preempt_count > 0 ); |
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364 | suspend(); |
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365 | verify( disable_preempt_count > 0 ); |
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366 | enable_interrupts( DEBUG_CTX ); |
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367 | } |
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368 | |
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369 | void BlockInternal( spinlock * lock ) { |
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370 | disable_interrupts(); |
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371 | this_processor->finish.action_code = Release; |
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372 | this_processor->finish.lock = lock; |
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373 | |
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374 | verify( disable_preempt_count > 0 ); |
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375 | suspend(); |
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376 | verify( disable_preempt_count > 0 ); |
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377 | |
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378 | enable_interrupts( DEBUG_CTX ); |
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379 | } |
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380 | |
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381 | void BlockInternal( thread_desc * thrd ) { |
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382 | disable_interrupts(); |
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383 | assert( thrd->cor.state != Halted ); |
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384 | this_processor->finish.action_code = Schedule; |
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385 | this_processor->finish.thrd = thrd; |
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386 | |
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387 | verify( disable_preempt_count > 0 ); |
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388 | suspend(); |
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389 | verify( disable_preempt_count > 0 ); |
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390 | |
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391 | enable_interrupts( DEBUG_CTX ); |
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392 | } |
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393 | |
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394 | void BlockInternal( spinlock * lock, thread_desc * thrd ) { |
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395 | disable_interrupts(); |
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396 | this_processor->finish.action_code = Release_Schedule; |
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397 | this_processor->finish.lock = lock; |
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398 | this_processor->finish.thrd = thrd; |
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399 | |
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400 | verify( disable_preempt_count > 0 ); |
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401 | suspend(); |
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402 | verify( disable_preempt_count > 0 ); |
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403 | |
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404 | enable_interrupts( DEBUG_CTX ); |
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405 | } |
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406 | |
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407 | void BlockInternal(spinlock ** locks, unsigned short count) { |
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408 | disable_interrupts(); |
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409 | this_processor->finish.action_code = Release_Multi; |
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410 | this_processor->finish.locks = locks; |
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411 | this_processor->finish.lock_count = count; |
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412 | |
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413 | verify( disable_preempt_count > 0 ); |
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414 | suspend(); |
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415 | verify( disable_preempt_count > 0 ); |
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416 | |
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417 | enable_interrupts( DEBUG_CTX ); |
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418 | } |
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419 | |
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420 | void BlockInternal(spinlock ** locks, unsigned short lock_count, thread_desc ** thrds, unsigned short thrd_count) { |
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421 | disable_interrupts(); |
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422 | this_processor->finish.action_code = Release_Multi_Schedule; |
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423 | this_processor->finish.locks = locks; |
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424 | this_processor->finish.lock_count = lock_count; |
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425 | this_processor->finish.thrds = thrds; |
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426 | this_processor->finish.thrd_count = thrd_count; |
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427 | |
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428 | verify( disable_preempt_count > 0 ); |
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429 | suspend(); |
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430 | verify( disable_preempt_count > 0 ); |
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431 | |
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432 | enable_interrupts( DEBUG_CTX ); |
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433 | } |
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434 | |
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435 | void LeaveThread(spinlock * lock, thread_desc * thrd) { |
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436 | verify( disable_preempt_count > 0 ); |
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437 | this_processor->finish.action_code = thrd ? Release_Schedule : Release; |
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438 | this_processor->finish.lock = lock; |
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439 | this_processor->finish.thrd = thrd; |
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440 | |
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441 | suspend(); |
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442 | } |
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443 | |
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444 | //============================================================================================= |
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445 | // Kernel Setup logic |
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446 | //============================================================================================= |
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447 | //----------------------------------------------------------------------------- |
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448 | // Kernel boot procedures |
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449 | void kernel_startup(void) { |
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450 | LIB_DEBUG_PRINT_SAFE("Kernel : Starting\n"); |
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451 | |
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452 | // Start by initializing the main thread |
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453 | // SKULLDUGGERY: the mainThread steals the process main thread |
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454 | // which will then be scheduled by the systemProcessor normally |
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455 | mainThread = (thread_desc *)&mainThreadStorage; |
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456 | current_stack_info_t info; |
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457 | mainThread{ &info }; |
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458 | |
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459 | LIB_DEBUG_PRINT_SAFE("Kernel : Main thread ready\n"); |
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460 | |
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461 | // Initialize the system cluster |
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462 | systemCluster = (cluster *)&systemClusterStorage; |
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463 | systemCluster{}; |
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464 | |
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465 | LIB_DEBUG_PRINT_SAFE("Kernel : System cluster ready\n"); |
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466 | |
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467 | // Initialize the system processor and the system processor ctx |
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468 | // (the coroutine that contains the processing control flow) |
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469 | systemProcessor = (system_proc_t *)&systemProcessorStorage; |
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470 | systemProcessor{ systemCluster, (processorCtx_t *)&systemProcessorCtxStorage }; |
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471 | |
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472 | // Add the main thread to the ready queue |
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473 | // once resume is called on systemProcessor->runner the mainThread needs to be scheduled like any normal thread |
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474 | ScheduleThread(mainThread); |
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475 | |
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476 | //initialize the global state variables |
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477 | this_processor = &systemProcessor->proc; |
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478 | this_thread = mainThread; |
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479 | this_coroutine = &mainThread->cor; |
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480 | disable_preempt_count = 1; |
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481 | |
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482 | // Enable preemption |
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483 | kernel_start_preemption(); |
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484 | |
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485 | // SKULLDUGGERY: Force a context switch to the system processor to set the main thread's context to the current UNIX |
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486 | // context. Hence, the main thread does not begin through CtxInvokeThread, like all other threads. The trick here is that |
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487 | // mainThread is on the ready queue when this call is made. |
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488 | resume( systemProcessor->proc.runner ); |
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489 | |
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490 | |
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491 | |
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492 | // THE SYSTEM IS NOW COMPLETELY RUNNING |
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493 | LIB_DEBUG_PRINT_SAFE("Kernel : Started\n--------------------------------------------------\n\n"); |
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494 | |
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495 | enable_interrupts( DEBUG_CTX ); |
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496 | } |
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497 | |
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498 | void kernel_shutdown(void) { |
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499 | LIB_DEBUG_PRINT_SAFE("\n--------------------------------------------------\nKernel : Shutting down\n"); |
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500 | |
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501 | disable_interrupts(); |
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502 | |
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503 | // SKULLDUGGERY: Notify the systemProcessor it needs to terminates. |
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504 | // When its coroutine terminates, it return control to the mainThread |
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505 | // which is currently here |
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506 | systemProcessor->proc.is_terminated = true; |
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507 | suspend(); |
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508 | |
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509 | // THE SYSTEM IS NOW COMPLETELY STOPPED |
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510 | |
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511 | // Disable preemption |
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512 | kernel_stop_preemption(); |
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513 | |
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514 | // Destroy the system processor and its context in reverse order of construction |
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515 | // These were manually constructed so we need manually destroy them |
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516 | ^(systemProcessor->proc.runner){}; |
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517 | ^(systemProcessor){}; |
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518 | |
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519 | // Final step, destroy the main thread since it is no longer needed |
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520 | // Since we provided a stack to this taxk it will not destroy anything |
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521 | ^(mainThread){}; |
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522 | |
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523 | LIB_DEBUG_PRINT_SAFE("Kernel : Shutdown complete\n"); |
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524 | } |
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525 | |
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526 | static spinlock kernel_abort_lock; |
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527 | static spinlock kernel_debug_lock; |
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528 | static bool kernel_abort_called = false; |
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529 | |
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530 | void * kernel_abort (void) __attribute__ ((__nothrow__)) { |
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531 | // abort cannot be recursively entered by the same or different processors because all signal handlers return when |
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532 | // the globalAbort flag is true. |
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533 | lock( &kernel_abort_lock DEBUG_CTX2 ); |
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534 | |
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535 | // first task to abort ? |
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536 | if ( !kernel_abort_called ) { // not first task to abort ? |
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537 | kernel_abort_called = true; |
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538 | unlock( &kernel_abort_lock ); |
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539 | } |
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540 | else { |
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541 | unlock( &kernel_abort_lock ); |
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542 | |
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543 | sigset_t mask; |
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544 | sigemptyset( &mask ); |
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545 | sigaddset( &mask, SIGALRM ); // block SIGALRM signals |
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546 | sigaddset( &mask, SIGUSR1 ); // block SIGUSR1 signals |
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547 | sigsuspend( &mask ); // block the processor to prevent further damage during abort |
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548 | _exit( EXIT_FAILURE ); // if processor unblocks before it is killed, terminate it |
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549 | } |
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550 | |
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551 | return this_thread; |
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552 | } |
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553 | |
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554 | void kernel_abort_msg( void * kernel_data, char * abort_text, int abort_text_size ) { |
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555 | thread_desc * thrd = kernel_data; |
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556 | |
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557 | int len = snprintf( abort_text, abort_text_size, "Error occurred while executing task %.256s (%p)", thrd->cor.name, thrd ); |
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558 | __lib_debug_write( STDERR_FILENO, abort_text, len ); |
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559 | |
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560 | if ( thrd != this_coroutine ) { |
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561 | len = snprintf( abort_text, abort_text_size, " in coroutine %.256s (%p).\n", this_coroutine->name, this_coroutine ); |
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562 | __lib_debug_write( STDERR_FILENO, abort_text, len ); |
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563 | } |
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564 | else { |
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565 | __lib_debug_write( STDERR_FILENO, ".\n", 2 ); |
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566 | } |
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567 | } |
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568 | |
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569 | extern "C" { |
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570 | void __lib_debug_acquire() { |
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571 | lock( &kernel_debug_lock DEBUG_CTX2 ); |
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572 | } |
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573 | |
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574 | void __lib_debug_release() { |
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575 | unlock( &kernel_debug_lock ); |
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576 | } |
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577 | } |
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578 | |
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579 | //============================================================================================= |
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580 | // Kernel Utilities |
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581 | //============================================================================================= |
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582 | //----------------------------------------------------------------------------- |
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583 | // Locks |
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584 | void ?{}( spinlock & this ) { |
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585 | this.lock = 0; |
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586 | } |
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587 | void ^?{}( spinlock & this ) { |
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588 | |
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589 | } |
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590 | |
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591 | bool try_lock( spinlock * this DEBUG_CTX_PARAM2 ) { |
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592 | return this->lock == 0 && __sync_lock_test_and_set_4( &this->lock, 1 ) == 0; |
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593 | } |
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594 | |
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595 | void lock( spinlock * this DEBUG_CTX_PARAM2 ) { |
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596 | for ( unsigned int i = 1;; i += 1 ) { |
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597 | if ( this->lock == 0 && __sync_lock_test_and_set_4( &this->lock, 1 ) == 0 ) { break; } |
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598 | } |
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599 | LIB_DEBUG_DO( |
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600 | this->prev_name = caller; |
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601 | this->prev_thrd = this_thread; |
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602 | ) |
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603 | } |
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604 | |
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605 | void lock_yield( spinlock * this DEBUG_CTX_PARAM2 ) { |
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606 | for ( unsigned int i = 1;; i += 1 ) { |
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607 | if ( this->lock == 0 && __sync_lock_test_and_set_4( &this->lock, 1 ) == 0 ) { break; } |
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608 | yield(); |
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609 | } |
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610 | LIB_DEBUG_DO( |
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611 | this->prev_name = caller; |
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612 | this->prev_thrd = this_thread; |
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613 | ) |
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614 | } |
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615 | |
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616 | |
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617 | void unlock( spinlock * this ) { |
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618 | __sync_lock_release_4( &this->lock ); |
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619 | } |
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620 | |
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621 | void ?{}( semaphore & this, int count = 1 ) { |
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622 | (this.lock){}; |
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623 | this.count = count; |
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624 | (this.waiting){}; |
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625 | } |
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626 | void ^?{}(semaphore & this) {} |
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627 | |
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628 | void P(semaphore * this) { |
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629 | lock( &this->lock DEBUG_CTX2 ); |
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630 | this->count -= 1; |
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631 | if ( this->count < 0 ) { |
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632 | // queue current task |
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633 | append( &this->waiting, (thread_desc *)this_thread ); |
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634 | |
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635 | // atomically release spin lock and block |
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636 | BlockInternal( &this->lock ); |
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637 | } |
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638 | else { |
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639 | unlock( &this->lock ); |
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640 | } |
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641 | } |
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642 | |
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643 | void V(semaphore * this) { |
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644 | thread_desc * thrd = NULL; |
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645 | lock( &this->lock DEBUG_CTX2 ); |
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646 | this->count += 1; |
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647 | if ( this->count <= 0 ) { |
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648 | // remove task at head of waiting list |
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649 | thrd = pop_head( &this->waiting ); |
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650 | } |
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651 | |
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652 | unlock( &this->lock ); |
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653 | |
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654 | // make new owner |
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655 | WakeThread( thrd ); |
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656 | } |
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657 | |
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658 | //----------------------------------------------------------------------------- |
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659 | // Queues |
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660 | void ?{}( __thread_queue_t & this ) { |
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661 | this.head = NULL; |
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662 | this.tail = &this.head; |
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663 | } |
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664 | |
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665 | void append( __thread_queue_t * this, thread_desc * t ) { |
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666 | verify(this->tail != NULL); |
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667 | *this->tail = t; |
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668 | this->tail = &t->next; |
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669 | } |
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670 | |
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671 | thread_desc * pop_head( __thread_queue_t * this ) { |
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672 | thread_desc * head = this->head; |
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673 | if( head ) { |
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674 | this->head = head->next; |
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675 | if( !head->next ) { |
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676 | this->tail = &this->head; |
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677 | } |
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678 | head->next = NULL; |
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679 | } |
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680 | return head; |
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681 | } |
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682 | |
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683 | void ?{}( __condition_stack_t & this ) { |
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684 | this.top = NULL; |
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685 | } |
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686 | |
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687 | void push( __condition_stack_t * this, __condition_criterion_t * t ) { |
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688 | verify( !t->next ); |
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689 | t->next = this->top; |
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690 | this->top = t; |
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691 | } |
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692 | |
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693 | __condition_criterion_t * pop( __condition_stack_t * this ) { |
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694 | __condition_criterion_t * top = this->top; |
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695 | if( top ) { |
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696 | this->top = top->next; |
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697 | top->next = NULL; |
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698 | } |
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699 | return top; |
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700 | } |
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701 | // Local Variables: // |
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702 | // mode: c // |
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703 | // tab-width: 4 // |
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704 | // End: // |
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