1 | /* |
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2 | * page.c :- This file contains implementation of C function to |
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3 | * Instanciate paging. More detailled information |
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4 | * can be found on Intel site and more precisely in |
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5 | * the following book : |
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6 | * |
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7 | * Pentium Processor familly |
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8 | * Developper's Manual |
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9 | * |
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10 | * Volume 3 : Architecture and Programming Manual |
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11 | * |
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12 | * Copyright (C) 1999 Emmanuel Raguet (raguet@crf.canon.fr) |
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13 | * Canon Centre Recherche France. |
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14 | * |
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15 | * The license and distribution terms for this file may be |
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16 | * found in found in the file LICENSE in this distribution or at |
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17 | * http://www.rtems.com/license/LICENSE. |
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18 | * |
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19 | * $Header$ |
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20 | */ |
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21 | |
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22 | #include <stdio.h> |
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23 | #include <stdlib.h> |
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24 | #include <string.h> |
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25 | #include <rtems.h> |
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26 | #include <libcpu/cpu.h> |
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27 | |
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28 | #define MEMORY_SIZE 0x4000000 /* 64Mo */ |
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29 | |
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30 | static int directoryEntry=0; |
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31 | static int tableEntry=0; |
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32 | static page_directory *pageDirectory; |
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33 | |
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34 | extern uint32_t rtemsFreeMemStart; |
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35 | |
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36 | |
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37 | /*************************************************************************/ |
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38 | /************** IT IS A ONE-TO-ONE TRANSLATION ***************************/ |
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39 | /*************************************************************************/ |
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40 | |
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41 | |
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42 | /* |
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43 | * Disable the paging |
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44 | */ |
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45 | void _CPU_disable_paging() { |
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46 | cr0 regCr0; |
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47 | |
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48 | rtems_cache_flush_entire_data(); |
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49 | regCr0.i = i386_get_cr0(); |
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50 | regCr0.cr0.paging = 0; |
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51 | i386_set_cr0( regCr0.i ); |
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52 | } |
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53 | |
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54 | /* |
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55 | * Enable the paging |
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56 | */ |
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57 | void _CPU_enable_paging() { |
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58 | cr0 regCr0; |
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59 | |
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60 | regCr0.i = i386_get_cr0(); |
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61 | regCr0.cr0.paging = 1; |
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62 | i386_set_cr0( regCr0.i ); |
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63 | rtems_cache_flush_entire_data(); |
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64 | } |
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65 | |
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66 | |
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67 | /* |
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68 | * Initialize the paging with 1-to-1 mapping |
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69 | */ |
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70 | |
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71 | int init_paging() { |
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72 | |
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73 | int memorySize; |
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74 | int nbPages; |
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75 | int nbInitPages; |
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76 | char *Tables; |
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77 | cr3 regCr3; |
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78 | page_table *pageTable; |
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79 | unsigned int physPage; |
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80 | int nbTables=0; |
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81 | |
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82 | /* |
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83 | * rtemsFreeMemStart is the last valid 32-bits address |
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84 | * so the size is rtemsFreeMemStart + 4 |
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85 | */ |
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86 | memorySize = rtemsFreeMemStart + 4; |
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87 | |
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88 | nbPages = ( (memorySize - 1) / PG_SIZE ) + 1; |
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89 | nbTables = ( (memorySize - 1) / FOUR_MB ) + 2; |
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90 | |
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91 | /* allocate 1 page more to page alignement */ |
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92 | Tables = (char *)malloc( (nbTables + 1)*sizeof(page_table) ); |
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93 | if ( Tables == NULL ){ |
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94 | return -1; /*unable to allocate memory */ |
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95 | } |
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96 | |
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97 | /* 4K-page alignement */ |
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98 | Tables += (PG_SIZE - (int)Tables) & 0xFFF; |
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99 | |
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100 | /* Reset Tables */ |
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101 | memset( Tables, 0, nbTables*sizeof(page_table) ); |
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102 | pageDirectory = (page_directory *) Tables; |
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103 | pageTable = (page_table *)((int)Tables + PG_SIZE); |
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104 | |
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105 | nbInitPages = 0; |
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106 | directoryEntry = 0; |
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107 | tableEntry = 0; |
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108 | physPage = 0; |
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109 | |
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110 | while ( nbInitPages != nbPages ){ |
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111 | if ( tableEntry == 0 ){ |
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112 | pageDirectory->pageDirEntry[directoryEntry].bits.page_frame_address = (unsigned int)pageTable >> 12; |
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113 | pageDirectory->pageDirEntry[directoryEntry].bits.available = 0; |
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114 | pageDirectory->pageDirEntry[directoryEntry].bits.page_size = 0; |
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115 | pageDirectory->pageDirEntry[directoryEntry].bits.accessed = 0; |
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116 | pageDirectory->pageDirEntry[directoryEntry].bits.cache_disable = 0; |
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117 | pageDirectory->pageDirEntry[directoryEntry].bits.write_through = 0; |
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118 | pageDirectory->pageDirEntry[directoryEntry].bits.user = 1; |
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119 | pageDirectory->pageDirEntry[directoryEntry].bits.writable = 1; |
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120 | pageDirectory->pageDirEntry[directoryEntry].bits.present = 1; |
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121 | } |
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122 | pageTable->pageTableEntry[tableEntry].bits.page_frame_address = physPage; |
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123 | pageTable->pageTableEntry[tableEntry].bits.available = 0; |
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124 | pageTable->pageTableEntry[tableEntry].bits.dirty = 0; |
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125 | pageTable->pageTableEntry[tableEntry].bits.accessed = 0; |
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126 | pageTable->pageTableEntry[tableEntry].bits.cache_disable = 0; |
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127 | pageTable->pageTableEntry[tableEntry].bits.write_through = 0; |
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128 | pageTable->pageTableEntry[tableEntry].bits.user = 1; |
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129 | pageTable->pageTableEntry[tableEntry].bits.writable = 1; |
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130 | pageTable->pageTableEntry[tableEntry].bits.present = 1; |
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131 | |
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132 | physPage ++; |
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133 | tableEntry ++; |
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134 | |
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135 | if (tableEntry >= MAX_ENTRY){ |
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136 | tableEntry = 0; |
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137 | directoryEntry ++; |
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138 | pageTable ++; |
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139 | } |
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140 | |
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141 | nbInitPages++; |
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142 | } |
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143 | |
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144 | regCr3.cr3.page_write_transparent = 0; |
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145 | regCr3.cr3.page_cache_disable = 0; |
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146 | regCr3.cr3.page_directory_base = (unsigned int)pageDirectory >> 12; |
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147 | |
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148 | i386_set_cr3( regCr3.i ); |
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149 | |
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150 | _CPU_enable_cache(); |
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151 | _CPU_enable_paging(); |
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152 | |
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153 | return 0; |
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154 | } |
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155 | |
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156 | /* |
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157 | * Is cache enable |
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158 | */ |
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159 | int _CPU_is_cache_enabled() { |
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160 | cr0 regCr0; |
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161 | |
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162 | regCr0.i = i386_get_cr0(); |
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163 | return( ~(regCr0.cr0.page_level_cache_disable) ); |
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164 | } |
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165 | |
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166 | /* |
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167 | * Is paging enable |
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168 | */ |
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169 | int _CPU_is_paging_enabled() { |
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170 | cr0 regCr0; |
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171 | |
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172 | regCr0.i = i386_get_cr0(); |
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173 | return(regCr0.cr0.paging); |
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174 | } |
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175 | |
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176 | |
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177 | /* |
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178 | * Translate the physical address in the virtual space and return |
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179 | * the translated address in mappedAddress |
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180 | */ |
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181 | |
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182 | int _CPU_map_phys_address |
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183 | (void **mappedAddress, void *physAddress, int size, int flag){ |
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184 | |
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185 | page_table *localPageTable; |
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186 | unsigned int lastAddress, countAddress; |
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187 | char *Tables; |
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188 | linear_address virtualAddress; |
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189 | unsigned char pagingWasEnabled; |
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190 | |
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191 | pagingWasEnabled = 0; |
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192 | |
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193 | if (_CPU_is_paging_enabled()){ |
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194 | pagingWasEnabled = 1; |
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195 | _CPU_disable_paging(); |
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196 | } |
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197 | |
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198 | countAddress = (unsigned int)physAddress; |
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199 | lastAddress = (unsigned int)physAddress + (size - 1); |
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200 | virtualAddress.address = 0; |
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201 | |
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202 | while (1){ |
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203 | |
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204 | if ((countAddress & ~MASK_OFFSET) > (lastAddress & ~MASK_OFFSET)) |
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205 | break; |
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206 | |
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207 | /* Need to allocate a new page table */ |
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208 | if (pageDirectory->pageDirEntry[directoryEntry].bits.page_frame_address == 0){ |
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209 | /* We allocate 2 pages to perform 4k-page alignement */ |
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210 | Tables = (char *)malloc(2*sizeof(page_table)); |
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211 | if ( Tables == NULL ){ |
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212 | if (pagingWasEnabled) |
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213 | _CPU_enable_paging(); |
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214 | return -1; /* unable to allocate memory */ |
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215 | } |
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216 | /* 4K-page alignement */ |
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217 | Tables += (PG_SIZE - (int)Tables) & 0xFFF; |
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218 | |
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219 | /* Reset Table */ |
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220 | memset( Tables, 0, sizeof(page_table) ); |
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221 | pageDirectory->pageDirEntry[directoryEntry].bits.page_frame_address = |
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222 | (unsigned int)Tables >> 12; |
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223 | pageDirectory->pageDirEntry[directoryEntry].bits.available = 0; |
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224 | pageDirectory->pageDirEntry[directoryEntry].bits.page_size = 0; |
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225 | pageDirectory->pageDirEntry[directoryEntry].bits.accessed = 0; |
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226 | pageDirectory->pageDirEntry[directoryEntry].bits.cache_disable = 0; |
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227 | pageDirectory->pageDirEntry[directoryEntry].bits.write_through = 0; |
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228 | pageDirectory->pageDirEntry[directoryEntry].bits.user = 1; |
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229 | pageDirectory->pageDirEntry[directoryEntry].bits.writable = 1; |
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230 | pageDirectory->pageDirEntry[directoryEntry].bits.present = 1; |
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231 | } |
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232 | |
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233 | |
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234 | localPageTable = (page_table *)(pageDirectory-> |
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235 | pageDirEntry[directoryEntry].bits. |
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236 | page_frame_address << 12); |
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237 | |
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238 | if (virtualAddress.address == 0){ |
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239 | virtualAddress.bits.directory = directoryEntry; |
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240 | virtualAddress.bits.page = tableEntry; |
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241 | virtualAddress.bits.offset = (unsigned int)physAddress & MASK_OFFSET; |
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242 | } |
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243 | |
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244 | localPageTable->pageTableEntry[tableEntry].bits.page_frame_address = |
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245 | ((unsigned int)countAddress & ~MASK_OFFSET) >> 12; |
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246 | localPageTable->pageTableEntry[tableEntry].bits.available = 0; |
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247 | localPageTable->pageTableEntry[tableEntry].bits.dirty = 0; |
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248 | localPageTable->pageTableEntry[tableEntry].bits.accessed = 0; |
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249 | localPageTable->pageTableEntry[tableEntry].bits.cache_disable = 0; |
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250 | localPageTable->pageTableEntry[tableEntry].bits.write_through = 0; |
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251 | localPageTable->pageTableEntry[tableEntry].bits.user = 1; |
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252 | localPageTable->pageTableEntry[tableEntry].bits.writable = 0; |
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253 | localPageTable->pageTableEntry[tableEntry].bits.present = 1; |
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254 | |
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255 | localPageTable->pageTableEntry[tableEntry].table_entry |= flag ; |
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256 | |
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257 | countAddress += PG_SIZE; |
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258 | tableEntry++; |
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259 | if (tableEntry >= MAX_ENTRY){ |
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260 | tableEntry = 0; |
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261 | directoryEntry++; |
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262 | } |
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263 | } |
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264 | |
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265 | if (mappedAddress != 0) |
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266 | *mappedAddress = (void *)(virtualAddress.address); |
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267 | if (pagingWasEnabled) |
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268 | _CPU_enable_paging(); |
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269 | return 0; |
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270 | } |
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271 | |
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272 | /* |
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273 | * "Compress" the Directory and Page tables to avoid |
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274 | * important loss of address range |
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275 | */ |
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276 | static void Paging_Table_Compress() { |
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277 | unsigned int dirCount, pageCount; |
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278 | page_table *localPageTable; |
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279 | |
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280 | if (tableEntry == 0){ |
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281 | dirCount = directoryEntry - 1; |
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282 | pageCount = MAX_ENTRY - 1; |
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283 | } |
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284 | else { |
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285 | dirCount = directoryEntry; |
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286 | pageCount = tableEntry - 1; |
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287 | } |
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288 | |
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289 | while (1){ |
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290 | |
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291 | localPageTable = (page_table *)(pageDirectory-> |
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292 | pageDirEntry[dirCount].bits. |
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293 | page_frame_address << 12); |
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294 | |
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295 | if (localPageTable->pageTableEntry[pageCount].bits.present == 1){ |
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296 | pageCount++; |
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297 | if (pageCount >= MAX_ENTRY){ |
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298 | pageCount = 0; |
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299 | dirCount++; |
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300 | } |
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301 | break; |
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302 | } |
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303 | |
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304 | |
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305 | if (pageCount == 0) { |
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306 | if (dirCount == 0){ |
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307 | break; |
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308 | } |
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309 | else { |
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310 | pageCount = MAX_ENTRY - 1; |
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311 | dirCount-- ; |
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312 | } |
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313 | } |
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314 | else |
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315 | pageCount-- ; |
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316 | } |
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317 | |
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318 | directoryEntry = dirCount; |
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319 | tableEntry = pageCount; |
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320 | } |
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321 | |
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322 | |
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323 | /* |
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324 | * Unmap the virtual address from the tables |
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325 | * (we do not deallocate the table already allocated) |
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326 | */ |
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327 | |
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328 | int _CPU_unmap_virt_address(void *mappedAddress, int size){ |
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329 | |
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330 | linear_address linearAddr; |
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331 | page_table *localPageTable; |
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332 | unsigned int lastAddr ; |
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333 | unsigned int dirCount ; |
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334 | unsigned char pagingWasEnabled; |
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335 | |
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336 | pagingWasEnabled = 0; |
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337 | |
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338 | if (_CPU_is_paging_enabled()){ |
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339 | pagingWasEnabled = 1; |
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340 | _CPU_disable_paging(); |
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341 | } |
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342 | |
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343 | linearAddr.address = (unsigned int)mappedAddress; |
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344 | lastAddr = (unsigned int)mappedAddress + (size - 1); |
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345 | dirCount = linearAddr.bits.directory; |
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346 | |
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347 | while (1){ |
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348 | |
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349 | if ((linearAddr.address & ~MASK_OFFSET) > (lastAddr & ~MASK_OFFSET)) |
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350 | break; |
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351 | |
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352 | if (pageDirectory->pageDirEntry[linearAddr.bits.directory].bits.present == 0){ |
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353 | if (pagingWasEnabled) |
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354 | _CPU_enable_paging(); |
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355 | return -1; |
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356 | } |
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357 | |
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358 | localPageTable = (page_table *)(pageDirectory-> |
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359 | pageDirEntry[linearAddr.bits.directory].bits. |
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360 | page_frame_address << 12); |
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361 | |
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362 | if (localPageTable->pageTableEntry[linearAddr.bits.page].bits.present == 0){ |
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363 | if (pagingWasEnabled) |
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364 | _CPU_enable_paging(); |
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365 | return -1; |
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366 | } |
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367 | |
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368 | localPageTable->pageTableEntry[linearAddr.bits.page].bits.present = 0; |
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369 | |
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370 | linearAddr.address += PG_SIZE ; |
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371 | } |
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372 | Paging_Table_Compress(); |
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373 | if (pagingWasEnabled) |
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374 | _CPU_enable_paging(); |
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375 | |
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376 | return 0; |
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377 | } |
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378 | |
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379 | /* |
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380 | * Modify the flags PRESENT, WRITABLE, USER, WRITE_TROUGH, CACHE_DISABLE |
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381 | * of the page's descriptor. |
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382 | */ |
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383 | |
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384 | int _CPU_change_memory_mapping_attribute |
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385 | (void **newAddress, void *mappedAddress, unsigned int size, unsigned int flag){ |
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386 | |
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387 | linear_address linearAddr; |
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388 | page_table *localPageTable; |
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389 | unsigned int lastAddr ; |
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390 | unsigned char pagingWasEnabled; |
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391 | |
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392 | pagingWasEnabled = 0; |
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393 | |
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394 | if (_CPU_is_paging_enabled()){ |
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395 | pagingWasEnabled = 1; |
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396 | _CPU_disable_paging(); |
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397 | } |
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398 | |
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399 | linearAddr.address = (unsigned int)mappedAddress; |
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400 | lastAddr = (unsigned int)mappedAddress + (size - 1); |
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401 | |
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402 | while (1){ |
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403 | |
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404 | if ((linearAddr.address & ~MASK_OFFSET) > (lastAddr & ~MASK_OFFSET)) |
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405 | break; |
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406 | |
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407 | if (pageDirectory->pageDirEntry[linearAddr.bits.directory].bits.present == 0){ |
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408 | if (pagingWasEnabled) |
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409 | _CPU_enable_paging(); |
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410 | return -1; |
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411 | } |
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412 | localPageTable = (page_table *)(pageDirectory-> |
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413 | pageDirEntry[linearAddr.bits.directory].bits. |
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414 | page_frame_address << 12); |
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415 | |
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416 | if (localPageTable->pageTableEntry[linearAddr.bits.page].bits.present == 0){ |
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417 | if (pagingWasEnabled) |
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418 | _CPU_enable_paging(); |
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419 | return -1; |
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420 | } |
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421 | |
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422 | localPageTable->pageTableEntry[linearAddr.bits.page].table_entry &= ~MASK_FLAGS ; |
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423 | localPageTable->pageTableEntry[linearAddr.bits.page].table_entry |= flag ; |
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424 | |
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425 | linearAddr.address += PG_SIZE ; |
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426 | } |
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427 | |
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428 | if (newAddress != NULL) |
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429 | *newAddress = mappedAddress ; |
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430 | |
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431 | if (pagingWasEnabled) |
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432 | _CPU_enable_paging(); |
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433 | |
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434 | return 0; |
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435 | } |
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436 | |
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437 | /* |
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438 | * Display the page descriptor flags |
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439 | * CACHE_DISABLE of the whole memory |
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440 | */ |
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441 | |
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442 | #include <rtems/bspIo.h> |
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443 | |
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444 | int _CPU_display_memory_attribute(){ |
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445 | unsigned int dirCount, pageCount; |
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446 | cr0 regCr0; |
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447 | page_table *localPageTable; |
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448 | unsigned int prevCache; |
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449 | unsigned int prevPresent; |
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450 | unsigned int maxPage; |
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451 | unsigned char pagingWasEnabled; |
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452 | |
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453 | regCr0.i = i386_get_cr0(); |
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454 | |
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455 | printk("\n\n >>>>>>>>> MEMORY CACHE CONFIGURATION <<<<<<<<<<\n\n"); |
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456 | |
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457 | printk("CR0 -> paging : %s\n",(regCr0.cr0.paging ? "ENABLE ":"DISABLE")); |
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458 | printk(" page-level cache : %s\n\n",(regCr0.cr0.page_level_cache_disable ? "DISABLE":"ENABLE")); |
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459 | |
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460 | if (regCr0.cr0.paging == 0) |
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461 | return 0; |
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462 | |
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463 | prevPresent = 0; |
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464 | prevCache = 1; |
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465 | |
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466 | pagingWasEnabled = 0; |
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467 | |
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468 | if (_CPU_is_paging_enabled()){ |
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469 | pagingWasEnabled = 1; |
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470 | _CPU_disable_paging(); |
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471 | } |
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472 | |
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473 | for (dirCount = 0; dirCount < directoryEntry+1; dirCount++) { |
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474 | |
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475 | localPageTable = (page_table *)(pageDirectory-> |
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476 | pageDirEntry[dirCount].bits. |
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477 | page_frame_address << 12); |
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478 | |
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479 | maxPage = MAX_ENTRY; |
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480 | /*if ( dirCount == (directoryEntry-1)) |
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481 | maxPage = tableEntry;*/ |
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482 | for (pageCount = 0; pageCount < maxPage; pageCount++) { |
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483 | |
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484 | if (localPageTable->pageTableEntry[pageCount].bits.present != 0){ |
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485 | if (prevPresent == 0){ |
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486 | prevPresent = 1; |
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487 | printk ("present page from address %x \n", ((dirCount << 22)|(pageCount << 12))); |
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488 | } |
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489 | if (prevCache != localPageTable->pageTableEntry[pageCount].bits.cache_disable ) { |
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490 | prevCache = localPageTable->pageTableEntry[pageCount]. |
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491 | bits.cache_disable; |
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492 | printk (" cache %s from %x <phy %x>\n", |
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493 | (prevCache ? "DISABLE" : "ENABLE "), |
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494 | ((dirCount << 22)|(pageCount << 12)), |
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495 | localPageTable->pageTableEntry[pageCount].bits.page_frame_address << 12); |
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496 | } |
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497 | } |
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498 | else { |
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499 | if (prevPresent == 1){ |
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500 | prevPresent = 0; |
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501 | printk ("Absent from %x \n", ((dirCount << 22)|(pageCount << 12))); |
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502 | } |
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503 | } |
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504 | } |
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505 | } |
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506 | if (pagingWasEnabled) |
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507 | _CPU_enable_paging(); |
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508 | return 0; |
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509 | |
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510 | } |
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