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 | // signal.c -- |
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9 | // |
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10 | // Author : Thierry Delisle |
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11 | // Created On : Mon Jun 5 14:20:42 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 | #include "preemption.h" |
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19 | |
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20 | extern "C" { |
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21 | #include <errno.h> |
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22 | #include <execinfo.h> |
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23 | #define __USE_GNU |
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24 | #include <signal.h> |
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25 | #undef __USE_GNU |
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26 | #include <stdio.h> |
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27 | #include <string.h> |
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28 | #include <unistd.h> |
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29 | } |
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30 | |
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31 | |
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32 | #ifdef __USE_STREAM__ |
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33 | #include "fstream" |
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34 | #endif |
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35 | |
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36 | #define __CFA_DEFAULT_PREEMPTION__ 10000 |
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37 | |
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38 | __attribute__((weak)) unsigned int default_preemption() { |
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39 | return __CFA_DEFAULT_PREEMPTION__; |
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40 | } |
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41 | |
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42 | #define __CFA_SIGCXT__ ucontext_t * |
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43 | #define __CFA_SIGPARMS__ __attribute__((unused)) int sig, __attribute__((unused)) siginfo_t *sfp, __attribute__((unused)) __CFA_SIGCXT__ cxt |
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44 | |
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45 | static void preempt( processor * this ); |
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46 | static void timeout( thread_desc * this ); |
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47 | |
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48 | void sigHandler_ctxSwitch( __CFA_SIGPARMS__ ); |
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49 | void sigHandler_alarm ( __CFA_SIGPARMS__ ); |
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50 | void sigHandler_segv ( __CFA_SIGPARMS__ ); |
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51 | void sigHandler_abort ( __CFA_SIGPARMS__ ); |
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52 | |
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53 | static void __kernel_sigaction( int sig, void (*handler)(__CFA_SIGPARMS__), int flags ); |
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54 | |
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55 | //============================================================================================= |
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56 | // Kernel Preemption logic |
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57 | //============================================================================================= |
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58 | |
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59 | void kernel_start_preemption() { |
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60 | LIB_DEBUG_PRINT_SAFE("Kernel : Starting preemption\n"); |
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61 | __kernel_sigaction( SIGUSR1, sigHandler_ctxSwitch, SA_SIGINFO ); |
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62 | __kernel_sigaction( SIGALRM, sigHandler_alarm , SA_SIGINFO ); |
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63 | __kernel_sigaction( SIGSEGV, sigHandler_segv , SA_SIGINFO ); |
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64 | __kernel_sigaction( SIGBUS , sigHandler_segv , SA_SIGINFO ); |
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65 | // __kernel_sigaction( SIGABRT, sigHandler_abort , SA_SIGINFO ); |
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66 | } |
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67 | |
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68 | void kernel_stop_preemption() { |
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69 | //Block all signals, we are no longer in a position to handle them |
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70 | sigset_t mask; |
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71 | sigfillset( &mask ); |
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72 | sigprocmask( SIG_BLOCK, &mask, NULL ); |
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73 | LIB_DEBUG_PRINT_SAFE("Kernel : Preemption stopped\n"); |
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74 | |
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75 | // assert( !systemProcessor->alarms.head ); |
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76 | // assert( systemProcessor->alarms.tail == &systemProcessor->alarms.head ); |
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77 | } |
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78 | |
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79 | LIB_DEBUG_DO( bool validate( alarm_list_t * this ); ) |
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80 | |
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81 | void tick_preemption() { |
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82 | // LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, "Ticking preemption\n" ); |
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83 | |
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84 | alarm_list_t * alarms = &systemProcessor->alarms; |
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85 | __cfa_time_t currtime = __kernel_get_time(); |
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86 | while( alarms->head && alarms->head->alarm < currtime ) { |
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87 | alarm_node_t * node = pop(alarms); |
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88 | // LIB_DEBUG_PRINT_BUFFER_LOCAL( STDERR_FILENO, "Ticking %p\n", node ); |
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89 | |
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90 | if( node->kernel_alarm ) { |
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91 | preempt( node->proc ); |
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92 | } |
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93 | else { |
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94 | timeout( node->thrd ); |
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95 | } |
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96 | |
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97 | verify( validate( alarms ) ); |
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98 | |
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99 | if( node->period > 0 ) { |
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100 | node->alarm = currtime + node->period; |
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101 | insert( alarms, node ); |
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102 | } |
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103 | else { |
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104 | node->set = false; |
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105 | } |
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106 | } |
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107 | |
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108 | if( alarms->head ) { |
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109 | __kernel_set_timer( alarms->head->alarm - currtime ); |
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110 | } |
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111 | |
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112 | verify( validate( alarms ) ); |
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113 | // LIB_DEBUG_PRINT_BUFFER_LOCAL( STDERR_FILENO, "Ticking preemption done\n" ); |
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114 | } |
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115 | |
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116 | void update_preemption( processor * this, __cfa_time_t duration ) { |
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117 | LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, "Processor : %p updating preemption to %lu\n", this, duration ); |
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118 | |
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119 | alarm_node_t * alarm = this->preemption_alarm; |
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120 | duration *= 1000; |
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121 | |
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122 | // Alarms need to be enabled |
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123 | if ( duration > 0 && !alarm->set ) { |
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124 | alarm->alarm = __kernel_get_time() + duration; |
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125 | alarm->period = duration; |
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126 | register_self( alarm ); |
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127 | } |
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128 | // Zero duraction but alarm is set |
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129 | else if ( duration == 0 && alarm->set ) { |
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130 | unregister_self( alarm ); |
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131 | alarm->alarm = 0; |
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132 | alarm->period = 0; |
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133 | } |
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134 | // If alarm is different from previous, change it |
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135 | else if ( duration > 0 && alarm->period != duration ) { |
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136 | unregister_self( alarm ); |
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137 | alarm->alarm = __kernel_get_time() + duration; |
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138 | alarm->period = duration; |
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139 | register_self( alarm ); |
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140 | } |
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141 | } |
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142 | |
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143 | void ?{}( preemption_scope * this, processor * proc ) { |
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144 | (&this->alarm){ proc }; |
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145 | this->proc = proc; |
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146 | this->proc->preemption_alarm = &this->alarm; |
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147 | update_preemption( this->proc, this->proc->preemption ); |
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148 | } |
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149 | |
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150 | void ^?{}( preemption_scope * this ) { |
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151 | disable_interrupts(); |
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152 | |
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153 | update_preemption( this->proc, 0 ); |
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154 | } |
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155 | |
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156 | //============================================================================================= |
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157 | // Kernel Signal logic |
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158 | //============================================================================================= |
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159 | |
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160 | LIB_DEBUG_DO( static thread_local void * last_interrupt = 0; ) |
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161 | |
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162 | extern "C" { |
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163 | void disable_interrupts() { |
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164 | __attribute__((unused)) unsigned short new_val = __atomic_add_fetch_2( &disable_preempt_count, 1, __ATOMIC_SEQ_CST ); |
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165 | verify( new_val < (unsigned short)65_000 ); |
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166 | verify( new_val != (unsigned short) 0 ); |
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167 | } |
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168 | |
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169 | void enable_interrupts_noRF() { |
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170 | __attribute__((unused)) unsigned short prev = __atomic_fetch_add_2( &disable_preempt_count, -1, __ATOMIC_SEQ_CST ); |
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171 | verify( prev != (unsigned short) 0 ); |
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172 | } |
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173 | |
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174 | void enable_interrupts( DEBUG_CTX_PARAM ) { |
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175 | processor * proc = this_processor; |
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176 | thread_desc * thrd = this_thread; |
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177 | unsigned short prev = __atomic_fetch_add_2( &disable_preempt_count, -1, __ATOMIC_SEQ_CST ); |
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178 | verify( prev != (unsigned short) 0 ); |
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179 | if( prev == 1 && proc->pending_preemption ) { |
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180 | proc->pending_preemption = false; |
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181 | BlockInternal( thrd ); |
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182 | } |
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183 | |
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184 | LIB_DEBUG_DO( proc->last_enable = caller; ) |
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185 | } |
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186 | } |
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187 | |
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188 | static inline void signal_unblock( int sig ) { |
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189 | LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, "Unblock %d on %p\n", sig, this_processor ); |
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190 | |
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191 | sigset_t mask; |
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192 | sigemptyset( &mask ); |
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193 | sigaddset( &mask, sig ); |
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194 | |
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195 | if ( pthread_sigmask( SIG_UNBLOCK, &mask, NULL ) == -1 ) { |
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196 | abortf( "internal error, pthread_sigmask" ); |
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197 | } // if |
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198 | } |
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199 | |
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200 | // static inline void signal_block( int sig ) { |
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201 | // sigset_t mask; |
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202 | // sigemptyset( &mask ); |
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203 | // sigaddset( &mask, sig ); |
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204 | |
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205 | // if ( pthread_sigmask( SIG_BLOCK, &mask, NULL ) == -1 ) { |
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206 | // abortf( "internal error, pthread_sigmask" ); |
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207 | // } // if |
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208 | // } |
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209 | |
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210 | static inline bool preemption_ready() { |
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211 | return disable_preempt_count == 0; |
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212 | } |
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213 | |
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214 | static inline void defer_ctxSwitch() { |
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215 | this_processor->pending_preemption = true; |
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216 | } |
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217 | |
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218 | static inline void defer_alarm() { |
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219 | systemProcessor->pending_alarm = true; |
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220 | } |
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221 | |
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222 | extern "C" { |
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223 | __attribute__((noinline)) void __debug_break() { |
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224 | pthread_kill( pthread_self(), SIGTRAP ); |
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225 | } |
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226 | } |
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227 | |
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228 | #ifdef __x86_64__ |
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229 | #define CFA_REG_IP REG_RIP |
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230 | #else |
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231 | #define CFA_REG_IP REG_EIP |
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232 | #endif |
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233 | |
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234 | void sigHandler_ctxSwitch( __CFA_SIGPARMS__ ) { |
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235 | LIB_DEBUG_DO( last_interrupt = (void *)(cxt->uc_mcontext.gregs[CFA_REG_IP]); ) |
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236 | verify( this_processor != systemProcessor ); |
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237 | |
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238 | if( preemption_ready() ) { |
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239 | signal_unblock( SIGUSR1 ); |
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240 | BlockInternal( (thread_desc*)this_thread ); |
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241 | } |
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242 | else { |
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243 | defer_ctxSwitch(); |
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244 | } |
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245 | } |
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246 | |
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247 | void sigHandler_alarm( __CFA_SIGPARMS__ ) { |
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248 | LIB_DEBUG_DO( last_interrupt = (void *)(cxt->uc_mcontext.gregs[CFA_REG_IP]); ) |
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249 | verify( this_processor == systemProcessor ); |
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250 | |
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251 | if( try_lock( &systemProcessor->alarm_lock DEBUG_CTX2 ) ) { |
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252 | tick_preemption(); |
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253 | systemProcessor->pending_alarm = false; |
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254 | unlock( &systemProcessor->alarm_lock ); |
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255 | } |
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256 | else { |
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257 | defer_alarm(); |
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258 | } |
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259 | |
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260 | signal_unblock( SIGALRM ); |
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261 | |
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262 | if( preemption_ready() && this_processor->pending_preemption ) { |
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263 | |
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264 | this_processor->pending_preemption = false; |
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265 | BlockInternal( (thread_desc*)this_thread ); |
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266 | } |
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267 | } |
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268 | |
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269 | static void preempt( processor * this ) { |
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270 | if( this != systemProcessor ) { |
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271 | pthread_kill( this->kernel_thread, SIGUSR1 ); |
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272 | } |
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273 | else { |
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274 | defer_ctxSwitch(); |
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275 | } |
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276 | } |
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277 | |
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278 | static void timeout( thread_desc * this ) { |
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279 | //TODO : implement waking threads |
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280 | } |
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281 | |
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282 | static void __kernel_sigaction( int sig, void (*handler)(__CFA_SIGPARMS__), int flags ) { |
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283 | struct sigaction act; |
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284 | |
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285 | act.sa_sigaction = (void (*)(int, siginfo_t *, void *))handler; |
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286 | act.sa_flags = flags; |
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287 | |
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288 | if ( sigaction( sig, &act, NULL ) == -1 ) { |
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289 | LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, |
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290 | " __kernel_sigaction( sig:%d, handler:%p, flags:%d ), problem installing signal handler, error(%d) %s.\n", |
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291 | sig, handler, flags, errno, strerror( errno ) |
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292 | ); |
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293 | _exit( EXIT_FAILURE ); |
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294 | } |
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295 | } |
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296 | |
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297 | typedef void (*sa_handler_t)(int); |
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298 | |
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299 | static void __kernel_sigdefault( int sig ) { |
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300 | struct sigaction act; |
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301 | |
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302 | // act.sa_handler = SIG_DFL; |
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303 | act.sa_flags = 0; |
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304 | sigemptyset( &act.sa_mask ); |
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305 | |
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306 | if ( sigaction( sig, &act, NULL ) == -1 ) { |
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307 | LIB_DEBUG_PRINT_BUFFER_DECL( STDERR_FILENO, |
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308 | " __kernel_sigdefault( sig:%d ), problem reseting signal handler, error(%d) %s.\n", |
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309 | sig, errno, strerror( errno ) |
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310 | ); |
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311 | _exit( EXIT_FAILURE ); |
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312 | } |
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313 | } |
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314 | |
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315 | //============================================================================================= |
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316 | // Terminating Signals logic |
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317 | //============================================================================================= |
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318 | |
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319 | LIB_DEBUG_DO( |
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320 | static void __kernel_backtrace( int start ) { |
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321 | // skip first N stack frames |
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322 | |
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323 | enum { Frames = 50 }; |
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324 | void * array[Frames]; |
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325 | int size = backtrace( array, Frames ); |
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326 | char ** messages = backtrace_symbols( array, size ); |
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327 | |
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328 | // find executable name |
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329 | *index( messages[0], '(' ) = '\0'; |
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330 | #ifdef __USE_STREAM__ |
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331 | serr | "Stack back trace for:" | messages[0] | endl; |
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332 | #else |
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333 | fprintf( stderr, "Stack back trace for: %s\n", messages[0]); |
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334 | #endif |
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335 | |
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336 | // skip last 2 stack frames after main |
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337 | for ( int i = start; i < size && messages != NULL; i += 1 ) { |
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338 | char * name = NULL; |
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339 | char * offset_begin = NULL; |
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340 | char * offset_end = NULL; |
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341 | |
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342 | for ( char *p = messages[i]; *p; ++p ) { |
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343 | // find parantheses and +offset |
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344 | if ( *p == '(' ) { |
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345 | name = p; |
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346 | } |
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347 | else if ( *p == '+' ) { |
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348 | offset_begin = p; |
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349 | } |
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350 | else if ( *p == ')' ) { |
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351 | offset_end = p; |
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352 | break; |
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353 | } |
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354 | } |
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355 | |
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356 | // if line contains symbol print it |
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357 | int frameNo = i - start; |
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358 | if ( name && offset_begin && offset_end && name < offset_begin ) { |
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359 | // delimit strings |
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360 | *name++ = '\0'; |
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361 | *offset_begin++ = '\0'; |
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362 | *offset_end++ = '\0'; |
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363 | |
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364 | #ifdef __USE_STREAM__ |
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365 | serr | "(" | frameNo | ")" | messages[i] | ":" |
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366 | | name | "+" | offset_begin | offset_end | endl; |
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367 | #else |
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368 | fprintf( stderr, "(%i) %s : %s + %s %s\n", frameNo, messages[i], name, offset_begin, offset_end); |
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369 | #endif |
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370 | } |
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371 | // otherwise, print the whole line |
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372 | else { |
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373 | #ifdef __USE_STREAM__ |
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374 | serr | "(" | frameNo | ")" | messages[i] | endl; |
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375 | #else |
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376 | fprintf( stderr, "(%i) %s\n", frameNo, messages[i] ); |
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377 | #endif |
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378 | } |
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379 | } |
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380 | |
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381 | free( messages ); |
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382 | } |
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383 | ) |
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384 | |
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385 | void sigHandler_segv( __CFA_SIGPARMS__ ) { |
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386 | LIB_DEBUG_DO( |
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387 | #ifdef __USE_STREAM__ |
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388 | serr | "*CFA runtime error* program cfa-cpp terminated with" |
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389 | | (sig == SIGSEGV ? "segment fault." : "bus error.") |
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390 | | endl; |
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391 | #else |
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392 | fprintf( stderr, "*CFA runtime error* program cfa-cpp terminated with %s\n", sig == SIGSEGV ? "segment fault." : "bus error." ); |
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393 | #endif |
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394 | |
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395 | // skip first 2 stack frames |
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396 | __kernel_backtrace( 1 ); |
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397 | ) |
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398 | exit( EXIT_FAILURE ); |
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399 | } |
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400 | |
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401 | // void sigHandler_abort( __CFA_SIGPARMS__ ) { |
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402 | // // skip first 6 stack frames |
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403 | // LIB_DEBUG_DO( __kernel_backtrace( 6 ); ) |
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404 | |
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405 | // // reset default signal handler |
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406 | // __kernel_sigdefault( SIGABRT ); |
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407 | |
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408 | // raise( SIGABRT ); |
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409 | // } |
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