1 | ////////////////////////////////////////////////////////////////////////////////// |
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2 | // File : ctx_handler.c |
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3 | // Date : 01/04/2012 |
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4 | // Authors : alain greiner & joel porquet |
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5 | // Copyright (c) UPMC-LIP6 |
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6 | ////////////////////////////////////////////////////////////////////////////////// |
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7 | |
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8 | #include <ctx_handler.h> |
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9 | #include <sys_handler.h> |
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10 | #include <giet_config.h> |
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11 | #include <hard_config.h> |
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12 | #include <utils.h> |
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13 | #include <tty0.h> |
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14 | #include <xcu_driver.h> |
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15 | #include <fat32.h> |
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16 | #include <elf-types.h> |
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17 | |
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18 | ///////////////////////////////////////////////////////////////////////////////// |
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19 | // Extern variables and functions |
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20 | ///////////////////////////////////////////////////////////////////////////////// |
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21 | |
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22 | // defined in giet_kernel/switch.s file |
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23 | extern void _task_switch(unsigned int *, unsigned int *); |
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24 | |
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25 | // allocated in boot.c or kernel_init.c files |
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26 | extern static_scheduler_t* _schedulers[X_SIZE][Y_SIZE][NB_PROCS_MAX]; |
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27 | |
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28 | |
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29 | /////////////////////////////////////////////// |
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30 | static void _ctx_kill_task( unsigned int ltid ) |
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31 | { |
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32 | // get scheduler address |
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33 | static_scheduler_t* psched = (static_scheduler_t*)_get_sched(); |
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34 | |
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35 | // pretend the task to kill is scheduled (required for sys_handler calls) |
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36 | unsigned int cur_task = psched->current; |
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37 | psched->current = ltid; |
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38 | |
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39 | // release private TTY terminal if required |
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40 | if ( psched->context[ltid][CTX_TTY_ID] < NB_TTY_CHANNELS ) |
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41 | { |
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42 | _sys_tty_release(); |
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43 | psched->context[ltid][CTX_TTY_ID] = -1; |
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44 | } |
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45 | |
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46 | // release private TIM channel if required |
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47 | if ( psched->context[ltid][CTX_TIM_ID] < NB_TIM_CHANNELS ) |
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48 | { |
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49 | _sys_tim_release(); |
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50 | psched->context[ltid][CTX_TIM_ID] = -1; |
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51 | } |
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52 | |
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53 | // release private NIC_RX channel if required |
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54 | if ( psched->context[ltid][CTX_NIC_RX_ID] < NB_NIC_CHANNELS ) |
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55 | { |
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56 | _sys_nic_release( 1 ); |
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57 | psched->context[ltid][CTX_NIC_RX_ID] = -1; |
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58 | } |
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59 | |
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60 | // release private NIC_TX channel if required |
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61 | if ( psched->context[ltid][CTX_NIC_TX_ID] < NB_NIC_CHANNELS ) |
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62 | { |
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63 | _sys_nic_release( 0 ); |
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64 | psched->context[ltid][CTX_NIC_TX_ID] = -1; |
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65 | } |
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66 | |
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67 | // release private FBF_CMA channel if required |
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68 | if ( psched->context[ltid][CTX_CMA_FB_ID] < NB_CMA_CHANNELS ) |
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69 | { |
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70 | _sys_fbf_cma_release(); |
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71 | psched->context[ltid][CTX_CMA_FB_ID] = -1; |
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72 | } |
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73 | |
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74 | // restore scheduled task |
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75 | psched->current = cur_task; |
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76 | |
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77 | // set NORUN_MASK_TASK bit |
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78 | _atomic_or( &psched->context[ltid][CTX_NORUN_ID], NORUN_MASK_TASK ); |
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79 | |
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80 | } // end _ctx_kill_task() |
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81 | |
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82 | |
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83 | |
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84 | //////////////////////////////////////////////////////////////////////// |
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85 | static unsigned int _load_writable_segments( mapping_vspace_t* vspace ) |
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86 | { |
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87 | |
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88 | #if GIET_DEBUG_SWITCH |
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89 | unsigned int gpid = _get_procid(); |
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90 | unsigned int cluster_xy = gpid >> P_WIDTH; |
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91 | unsigned int p = gpid & ((1<<P_WIDTH)-1); |
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92 | unsigned int x = cluster_xy >> Y_WIDTH; |
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93 | unsigned int y = cluster_xy & ((1<<Y_WIDTH)-1); |
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94 | if ( _get_proctime() > GIET_DEBUG_SWITCH ) |
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95 | _printf("\n[DEBUG SWITCH] P[%d,%d,%d] _load_writable_segments() : enters for %s\n", |
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96 | x , y , p , vspace->name ); |
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97 | #endif |
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98 | |
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99 | mapping_header_t* header = (mapping_header_t *)SEG_BOOT_MAPPING_BASE; |
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100 | mapping_vseg_t* vseg = _get_vseg_base(header); |
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101 | |
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102 | // buffer to store one cluster |
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103 | char buf[4096]; |
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104 | |
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105 | // open the .elf file associated to vspace |
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106 | unsigned int vseg_id; |
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107 | unsigned int fd = 0; |
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108 | |
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109 | for (vseg_id = vspace->vseg_offset; |
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110 | vseg_id < (vspace->vseg_offset + vspace->vsegs); |
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111 | vseg_id++) |
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112 | { |
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113 | if(vseg[vseg_id].type == VSEG_TYPE_ELF) |
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114 | { |
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115 | fd = _fat_open( vseg[vseg_id].binpath , O_RDONLY ); |
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116 | |
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117 | #if GIET_DEBUG_SWITCH |
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118 | if ( _get_proctime() > GIET_DEBUG_SWITCH ) |
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119 | _printf("\n[DEBUG SWITCH] P[%d,%d,%d] _load_writable_segments() : open %s / fd = %d\n", |
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120 | x , y , p , vseg[vseg_id].binpath , fd ); |
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121 | #endif |
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122 | |
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123 | if ( fd < 0 ) return 1; |
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124 | break; |
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125 | } |
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126 | } |
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127 | |
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128 | // load Elf-Header into buffer from .elf file |
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129 | if ( _fat_lseek( fd, 0, SEEK_SET ) ) return 1; |
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130 | if ( _fat_read( fd, buf, 4096 ) ) return 1; |
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131 | |
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132 | #if GIET_DEBUG_SWITCH |
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133 | if ( _get_proctime() > GIET_DEBUG_SWITCH ) |
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134 | _printf("\n[DEBUG SWITCH] P[%d,%d,%d] _load_writable_segments() : load Elf-Header\n", |
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135 | x , y , p ); |
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136 | #endif |
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137 | |
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138 | // get nsegments and Program-Header-Table offset from Elf-Header |
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139 | Elf32_Ehdr* elf_header_ptr = (Elf32_Ehdr*)buf; |
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140 | unsigned int offset = elf_header_ptr->e_phoff; |
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141 | unsigned int nsegments = elf_header_ptr->e_phnum; |
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142 | |
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143 | // load Program-Header-Table from .elf file |
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144 | if ( _fat_lseek( fd, offset, SEEK_SET ) ) return 1; |
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145 | if ( _fat_read( fd, buf, 4096 ) ) return 1; |
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146 | |
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147 | #if GIET_DEBUG_SWITCH |
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148 | if ( _get_proctime() > GIET_DEBUG_SWITCH ) |
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149 | _printf("\n[DEBUG SWITCH] P[%d,%d,%d] _load_writable_segments() : " |
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150 | "load Program-Header-Table\n", x , y , p ); |
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151 | #endif |
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152 | |
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153 | // set Program-Header-Table pointer |
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154 | Elf32_Phdr* elf_pht_ptr = (Elf32_Phdr*)buf; |
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155 | |
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156 | // scan segments to load all loadable & writable segments |
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157 | unsigned int seg_id; |
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158 | for (seg_id = 0 ; seg_id < nsegments ; seg_id++) |
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159 | { |
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160 | if ( (elf_pht_ptr[seg_id].p_type == PT_LOAD) && // loadable |
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161 | (elf_pht_ptr[seg_id].p_flags & PF_W) ) // writable |
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162 | { |
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163 | // Get segment attributes |
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164 | unsigned int seg_vaddr = elf_pht_ptr[seg_id].p_vaddr; |
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165 | unsigned int seg_offset = elf_pht_ptr[seg_id].p_offset; |
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166 | unsigned int seg_size = elf_pht_ptr[seg_id].p_filesz; |
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167 | |
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168 | // load the segment |
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169 | if ( _fat_lseek( fd, seg_offset, SEEK_SET ) ) return 1; |
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170 | if ( _fat_read( fd, (void*)seg_vaddr, seg_size ) ) return 1; |
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171 | |
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172 | #if GIET_DEBUG_SWITCH |
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173 | if ( _get_proctime() > GIET_DEBUG_SWITCH ) |
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174 | _printf("\n[DEBUG SWITCH] P[%d,%d,%d] _load_writable_segments() : load segment %x\n", |
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175 | x , y , p , seg_vaddr ); |
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176 | #endif |
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177 | |
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178 | } |
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179 | } // end loop on writable & loadable segments |
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180 | |
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181 | // close .elf file |
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182 | _fat_close( fd ); |
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183 | |
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184 | return 0; |
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185 | } // end load_writable_segments() |
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186 | |
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187 | |
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188 | |
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189 | /////////////////////////////////////////////// |
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190 | static void _ctx_exec_task( unsigned int ltid ) |
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191 | { |
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192 | // get pointers in mapping |
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193 | mapping_header_t * header = (mapping_header_t *)SEG_BOOT_MAPPING_BASE; |
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194 | mapping_task_t * task = _get_task_base(header); |
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195 | mapping_vseg_t * vseg = _get_vseg_base(header); |
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196 | mapping_vspace_t * vspace = _get_vspace_base(header); |
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197 | |
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198 | // get scheduler address for processor running the calling task |
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199 | static_scheduler_t* psched = (static_scheduler_t*)_get_sched(); |
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200 | |
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201 | // get global task index, vspace index, and stack vseg index |
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202 | unsigned int task_id = psched->context[ltid][CTX_GTID_ID]; |
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203 | unsigned int vspace_id = psched->context[ltid][CTX_VSID_ID]; |
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204 | unsigned int vseg_id = task[task_id].stack_vseg_id; |
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205 | |
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206 | #if GIET_DEBUG_SWITCH |
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207 | unsigned int gpid = _get_procid(); |
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208 | unsigned int cluster_xy = gpid >> P_WIDTH; |
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209 | unsigned int p = gpid & ((1<<P_WIDTH)-1); |
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210 | unsigned int x = cluster_xy >> Y_WIDTH; |
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211 | unsigned int y = cluster_xy & ((1<<Y_WIDTH)-1); |
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212 | if ( _get_proctime() > GIET_DEBUG_SWITCH ) |
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213 | _printf("\n[DEBUG SWITCH] P[%d,%d,%d] _ctx_exec_task() : enters for %s\n", |
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214 | x , y , p , task[task_id].name ); |
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215 | #endif |
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216 | |
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217 | // reload writable segments |
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218 | if ( _load_writable_segments( &vspace[vspace_id] ) ) |
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219 | { |
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220 | _printf("[GIET ERROR] in _ctx_exec_task() for task %s\n", |
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221 | task[task_id].name ); |
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222 | return; |
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223 | } |
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224 | |
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225 | // find initial stack pointer |
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226 | unsigned int sp_value = vseg[vseg_id].vbase + vseg[vseg_id].length; |
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227 | |
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228 | // reset task context: RA / SR / SP / EPC / NORUN |
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229 | psched->context[ltid][CTX_RA_ID] = (unsigned int)&_ctx_eret; |
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230 | psched->context[ltid][CTX_SR_ID] = GIET_SR_INIT_VALUE; |
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231 | psched->context[ltid][CTX_SP_ID] = sp_value; |
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232 | psched->context[ltid][CTX_EPC_ID] = psched->context[ltid][CTX_ENTRY_ID]; |
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233 | psched->context[ltid][CTX_NORUN_ID] = 0; |
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234 | } |
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235 | |
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236 | |
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237 | ////////////////////////////////// |
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238 | void _ctx_display( unsigned int x, |
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239 | unsigned int y, |
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240 | unsigned int p, |
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241 | unsigned int ltid, |
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242 | char* string ) |
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243 | { |
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244 | static_scheduler_t* psched = _schedulers[x][y][p]; |
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245 | _printf("\n########## task[%d,%d,%d,%d] context\n" |
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246 | " - CTX_EPC = %x\n" |
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247 | " - CTX_PTAB = %x\n" |
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248 | " - CTX_PTPR = %x\n" |
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249 | " - CTX_VSID = %x\n" |
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250 | " - CTX_SR = %x\n" |
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251 | " - CTX_RA = %x\n" |
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252 | " - CTX_SP = %x\n" |
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253 | " - CTX_NORUN = %x\n" |
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254 | " - CTX_SIG = %x\n" |
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255 | "########## %s\n", |
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256 | x , y , p , ltid , |
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257 | psched->context[ltid][CTX_EPC_ID], |
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258 | psched->context[ltid][CTX_PTAB_ID], |
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259 | psched->context[ltid][CTX_PTPR_ID], |
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260 | psched->context[ltid][CTX_VSID_ID], |
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261 | psched->context[ltid][CTX_SR_ID], |
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262 | psched->context[ltid][CTX_RA_ID], |
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263 | psched->context[ltid][CTX_SP_ID], |
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264 | psched->context[ltid][CTX_NORUN_ID], |
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265 | psched->context[ltid][CTX_SIG_ID], |
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266 | string ); |
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267 | } // _ctx_display() |
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268 | |
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269 | |
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270 | ////////////////// |
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271 | void _ctx_switch() |
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272 | { |
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273 | unsigned int gpid = _get_procid(); |
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274 | unsigned int cluster_xy = gpid >> P_WIDTH; |
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275 | unsigned int lpid = gpid & ((1<<P_WIDTH)-1); |
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276 | |
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277 | // get scheduler address |
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278 | static_scheduler_t* psched = (static_scheduler_t*)_get_sched(); |
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279 | |
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280 | // get number of tasks allocated to scheduler |
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281 | unsigned int tasks = psched->tasks; |
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282 | |
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283 | // get current task index |
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284 | unsigned int curr_task_id = psched->current; |
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285 | |
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286 | // select the next task using a round-robin policy |
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287 | unsigned int next_task_id; |
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288 | unsigned int tid; |
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289 | unsigned int found = 0; |
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290 | |
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291 | for (tid = curr_task_id + 1; tid < curr_task_id + 1 + tasks; tid++) |
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292 | { |
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293 | next_task_id = tid % tasks; |
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294 | |
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295 | // this task needs to be killed |
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296 | if ( psched->context[next_task_id][CTX_SIG_ID] & SIG_MASK_KILL ) |
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297 | { |
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298 | _ctx_kill_task( next_task_id ); |
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299 | |
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300 | // acknowledge signal |
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301 | _atomic_and( &psched->context[next_task_id][CTX_SIG_ID], ~SIG_MASK_KILL ); |
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302 | } |
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303 | |
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304 | // this task needs to be executed |
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305 | if ( psched->context[next_task_id][CTX_SIG_ID] & SIG_MASK_EXEC ) |
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306 | { |
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307 | _ctx_exec_task( next_task_id ); |
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308 | |
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309 | // acknowledge signal |
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310 | _atomic_and( &psched->context[next_task_id][CTX_SIG_ID], ~SIG_MASK_EXEC ); |
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311 | } |
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312 | |
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313 | // test if the task is runable |
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314 | if ( psched->context[next_task_id][CTX_NORUN_ID] == 0 ) |
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315 | { |
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316 | found = 1; |
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317 | // TODO: don't break to process all pending signals. |
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318 | break; |
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319 | } |
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320 | } |
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321 | |
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322 | // launch "idle" task if no runable task |
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323 | if (found == 0) next_task_id = IDLE_TASK_INDEX; |
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324 | |
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325 | #if ( GIET_DEBUG_SWITCH & 0x1 ) |
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326 | unsigned int x = cluster_xy >> Y_WIDTH; |
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327 | unsigned int y = cluster_xy & ((1<<Y_WIDTH)-1); |
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328 | if ( _get_proctime() > GIET_DEBUG_SWITCH ) |
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329 | _printf("\n[DEBUG SWITCH] (%d) -> (%d) on processor[%d,%d,%d] at cycle %d\n", |
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330 | curr_task_id, next_task_id, x, y , lpid, _get_proctime() ); |
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331 | #endif |
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332 | |
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333 | if (curr_task_id != next_task_id) // actual task switch required |
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334 | { |
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335 | unsigned int* curr_ctx_vaddr = &(psched->context[curr_task_id][0]); |
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336 | unsigned int* next_ctx_vaddr = &(psched->context[next_task_id][0]); |
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337 | |
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338 | // reset TICK timer counter. |
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339 | _xcu_timer_reset_cpt( cluster_xy, lpid ); |
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340 | |
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341 | // set current task index |
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342 | psched->current = next_task_id; |
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343 | |
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344 | // makes context switch |
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345 | _task_switch( curr_ctx_vaddr , next_ctx_vaddr ); |
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346 | } |
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347 | } //end _ctx_switch() |
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348 | |
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349 | |
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350 | ///////////////// |
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351 | void _idle_task() |
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352 | { |
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353 | unsigned int gpid = _get_procid(); |
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354 | unsigned int cluster_xy = gpid >> P_WIDTH; |
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355 | unsigned int x = cluster_xy >> Y_WIDTH; |
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356 | unsigned int y = cluster_xy & ((1<<Y_WIDTH)-1); |
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357 | unsigned int p = gpid & ((1<<P_WIDTH)-1); |
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358 | |
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359 | while(1) |
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360 | { |
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361 | // initialize counter |
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362 | unsigned int count = GIET_IDLE_TASK_PERIOD; |
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363 | |
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364 | // decounting loop |
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365 | asm volatile( |
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366 | "move $3, %0 \n" |
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367 | "_idle_task_loop: \n" |
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368 | "addi $3, $3, -1 \n" |
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369 | "bnez $3, _idle_task_loop \n" |
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370 | "nop \n" |
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371 | : |
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372 | : "r"(count) |
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373 | : "$3" ); |
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374 | |
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375 | // warning message |
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376 | _printf("\n[GIET WARNING] Processor[%d,%d,%d] still idle at cycle %d", |
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377 | x , y , p , _get_proctime() ); |
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378 | } |
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379 | } // end ctx_idle() |
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380 | |
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381 | |
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382 | //////////////// |
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383 | void _ctx_eret() |
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384 | { |
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385 | asm volatile("eret"); |
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386 | } |
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387 | |
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388 | |
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389 | // Local Variables: |
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390 | // tab-width: 4 |
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391 | // c-basic-offset: 4 |
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392 | // c-file-offsets:((innamespace . 0)(inline-open . 0)) |
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393 | // indent-tabs-mode: nil |
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394 | // End: |
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395 | // vim: filetype=c:expandtab:shiftwidth=4:tabstop=4:softtabstop=4 |
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396 | |
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