1 | #ifdef TARGET_DEFS_ONLY
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2 |
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3 | #define EM_TCC_TARGET EM_X86_64
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4 |
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5 | /* relocation type for 32 bit data relocation */
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6 | #define R_DATA_32 R_X86_64_32S
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7 | #define R_DATA_PTR R_X86_64_64
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8 | #define R_JMP_SLOT R_X86_64_JUMP_SLOT
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9 | #define R_GLOB_DAT R_X86_64_GLOB_DAT
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10 | #define R_COPY R_X86_64_COPY
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11 | #define R_RELATIVE R_X86_64_RELATIVE
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12 |
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13 | #define R_NUM R_X86_64_NUM
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14 |
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15 | #define ELF_START_ADDR 0x400000
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16 | #define ELF_PAGE_SIZE 0x200000
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17 |
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18 | #define PCRELATIVE_DLLPLT 1
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19 | #define RELOCATE_DLLPLT 1
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20 |
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21 | #else /* !TARGET_DEFS_ONLY */
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22 |
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23 | #include "tcc.h"
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24 |
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25 | /* Returns 1 for a code relocation, 0 for a data relocation. For unknown
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26 | relocations, returns -1. */
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27 | int code_reloc (int reloc_type)
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28 | {
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29 | switch (reloc_type) {
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30 | case R_X86_64_32:
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31 | case R_X86_64_32S:
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32 | case R_X86_64_64:
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33 | case R_X86_64_GOTPC32:
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34 | case R_X86_64_GOTPC64:
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35 | case R_X86_64_GOTPCREL:
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36 | case R_X86_64_GOTPCRELX:
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37 | case R_X86_64_REX_GOTPCRELX:
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38 | case R_X86_64_GOTTPOFF:
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39 | case R_X86_64_GOT32:
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40 | case R_X86_64_GOT64:
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41 | case R_X86_64_GLOB_DAT:
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42 | case R_X86_64_COPY:
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43 | case R_X86_64_RELATIVE:
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44 | case R_X86_64_GOTOFF64:
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45 | return 0;
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46 |
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47 | case R_X86_64_PC32:
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48 | case R_X86_64_PC64:
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49 | case R_X86_64_PLT32:
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50 | case R_X86_64_PLTOFF64:
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51 | case R_X86_64_JUMP_SLOT:
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52 | return 1;
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53 | }
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54 |
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55 | tcc_error ("Unknown relocation type: %d", reloc_type);
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56 | return -1;
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57 | }
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58 |
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59 | /* Returns an enumerator to describe whether and when the relocation needs a
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60 | GOT and/or PLT entry to be created. See tcc.h for a description of the
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61 | different values. */
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62 | int gotplt_entry_type (int reloc_type)
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63 | {
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64 | switch (reloc_type) {
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65 | case R_X86_64_GLOB_DAT:
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66 | case R_X86_64_JUMP_SLOT:
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67 | case R_X86_64_COPY:
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68 | case R_X86_64_RELATIVE:
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69 | return NO_GOTPLT_ENTRY;
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70 |
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71 | /* The following relocs wouldn't normally need GOT or PLT
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72 | slots, but we need them for simplicity in the link
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73 | editor part. See our caller for comments. */
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74 | case R_X86_64_32:
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75 | case R_X86_64_32S:
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76 | case R_X86_64_64:
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77 | case R_X86_64_PC32:
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78 | case R_X86_64_PC64:
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79 | return AUTO_GOTPLT_ENTRY;
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80 |
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81 | case R_X86_64_GOTTPOFF:
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82 | return BUILD_GOT_ONLY;
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83 |
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84 | case R_X86_64_GOT32:
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85 | case R_X86_64_GOT64:
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86 | case R_X86_64_GOTPC32:
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87 | case R_X86_64_GOTPC64:
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88 | case R_X86_64_GOTOFF64:
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89 | case R_X86_64_GOTPCREL:
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90 | case R_X86_64_GOTPCRELX:
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91 | case R_X86_64_REX_GOTPCRELX:
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92 | case R_X86_64_PLT32:
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93 | case R_X86_64_PLTOFF64:
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94 | return ALWAYS_GOTPLT_ENTRY;
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95 | }
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96 |
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97 | tcc_error ("Unknown relocation type: %d", reloc_type);
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98 | return -1;
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99 | }
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100 |
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101 | ST_FUNC unsigned create_plt_entry(TCCState *s1, unsigned got_offset, struct sym_attr *attr)
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102 | {
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103 | Section *plt = s1->plt;
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104 | uint8_t *p;
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105 | int modrm;
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106 | unsigned plt_offset, relofs;
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107 |
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108 | modrm = 0x25;
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109 |
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110 | /* empty PLT: create PLT0 entry that pushes the library identifier
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111 | (GOT + PTR_SIZE) and jumps to ld.so resolution routine
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112 | (GOT + 2 * PTR_SIZE) */
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113 | if (plt->data_offset == 0) {
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114 | p = section_ptr_add(plt, 16);
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115 | p[0] = 0xff; /* pushl got + PTR_SIZE */
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116 | p[1] = modrm + 0x10;
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117 | write32le(p + 2, PTR_SIZE);
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118 | p[6] = 0xff; /* jmp *(got + PTR_SIZE * 2) */
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119 | p[7] = modrm;
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120 | write32le(p + 8, PTR_SIZE * 2);
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121 | }
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122 | plt_offset = plt->data_offset;
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123 |
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124 | /* The PLT slot refers to the relocation entry it needs via offset.
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125 | The reloc entry is created below, so its offset is the current
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126 | data_offset */
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127 | relofs = s1->got->reloc ? s1->got->reloc->data_offset : 0;
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128 |
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129 | /* Jump to GOT entry where ld.so initially put the address of ip + 4 */
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130 | p = section_ptr_add(plt, 16);
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131 | p[0] = 0xff; /* jmp *(got + x) */
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132 | p[1] = modrm;
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133 | write32le(p + 2, got_offset);
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134 | p[6] = 0x68; /* push $xxx */
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135 | /* On x86-64, the relocation is referred to by _index_ */
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136 | write32le(p + 7, relofs / sizeof (ElfW_Rel));
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137 | p[11] = 0xe9; /* jmp plt_start */
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138 | write32le(p + 12, -(plt->data_offset));
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139 | return plt_offset;
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140 | }
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141 |
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142 | /* relocate the PLT: compute addresses and offsets in the PLT now that final
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143 | address for PLT and GOT are known (see fill_program_header) */
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144 | ST_FUNC void relocate_plt(TCCState *s1)
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145 | {
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146 | uint8_t *p, *p_end;
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147 |
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148 | if (!s1->plt)
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149 | return;
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150 |
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151 | p = s1->plt->data;
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152 | p_end = p + s1->plt->data_offset;
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153 |
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154 | if (p < p_end) {
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155 | int x = s1->got->sh_addr - s1->plt->sh_addr - 6;
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156 | add32le(p + 2, x);
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157 | add32le(p + 8, x - 6);
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158 | p += 16;
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159 | while (p < p_end) {
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160 | add32le(p + 2, x + s1->plt->data - p);
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161 | p += 16;
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162 | }
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163 | }
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164 | }
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165 |
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166 | static ElfW_Rel *qrel; /* ptr to next reloc entry reused */
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167 |
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168 | void relocate_init(Section *sr)
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169 | {
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170 | qrel = (ElfW_Rel *) sr->data;
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171 | }
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172 |
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173 | void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr, addr_t addr, addr_t val)
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174 | {
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175 | int sym_index, esym_index;
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176 |
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177 | sym_index = ELFW(R_SYM)(rel->r_info);
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178 |
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179 | switch (type) {
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180 | case R_X86_64_64:
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181 | if (s1->output_type == TCC_OUTPUT_DLL) {
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182 | esym_index = s1->sym_attrs[sym_index].dyn_index;
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183 | qrel->r_offset = rel->r_offset;
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184 | if (esym_index) {
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185 | qrel->r_info = ELFW(R_INFO)(esym_index, R_X86_64_64);
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186 | qrel->r_addend = rel->r_addend;
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187 | qrel++;
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188 | break;
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189 | } else {
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190 | qrel->r_info = ELFW(R_INFO)(0, R_X86_64_RELATIVE);
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191 | qrel->r_addend = read64le(ptr) + val;
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192 | qrel++;
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193 | }
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194 | }
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195 | add64le(ptr, val);
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196 | break;
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197 | case R_X86_64_32:
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198 | case R_X86_64_32S:
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199 | if (s1->output_type == TCC_OUTPUT_DLL) {
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200 | /* XXX: this logic may depend on TCC's codegen
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201 | now TCC uses R_X86_64_32 even for a 64bit pointer */
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202 | qrel->r_info = ELFW(R_INFO)(0, R_X86_64_RELATIVE);
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203 | /* Use sign extension! */
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204 | qrel->r_addend = (int)read32le(ptr) + val;
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205 | qrel++;
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206 | }
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207 | add32le(ptr, val);
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208 | break;
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209 |
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210 | case R_X86_64_PC32:
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211 | if (s1->output_type == TCC_OUTPUT_DLL) {
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212 | /* DLL relocation */
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213 | esym_index = s1->sym_attrs[sym_index].dyn_index;
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214 | if (esym_index) {
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215 | qrel->r_offset = rel->r_offset;
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216 | qrel->r_info = ELFW(R_INFO)(esym_index, R_X86_64_PC32);
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217 | /* Use sign extension! */
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218 | qrel->r_addend = (int)read32le(ptr) + rel->r_addend;
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219 | qrel++;
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220 | break;
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221 | }
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222 | }
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223 | goto plt32pc32;
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224 |
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225 | case R_X86_64_PLT32:
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226 | /* fallthrough: val already holds the PLT slot address */
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227 |
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228 | plt32pc32:
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229 | {
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230 | long long diff;
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231 | diff = (long long)val - addr;
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232 | if (diff < -2147483648LL || diff > 2147483647LL) {
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233 | tcc_error("internal error: relocation failed");
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234 | }
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235 | add32le(ptr, diff);
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236 | }
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237 | break;
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238 |
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239 | case R_X86_64_PLTOFF64:
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240 | add64le(ptr, val - s1->got->sh_addr + rel->r_addend);
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241 | break;
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242 |
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243 | case R_X86_64_PC64:
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244 | if (s1->output_type == TCC_OUTPUT_DLL) {
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245 | /* DLL relocation */
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246 | esym_index = s1->sym_attrs[sym_index].dyn_index;
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247 | if (esym_index) {
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248 | qrel->r_offset = rel->r_offset;
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249 | qrel->r_info = ELFW(R_INFO)(esym_index, R_X86_64_PC64);
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250 | qrel->r_addend = read64le(ptr) + rel->r_addend;
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251 | qrel++;
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252 | break;
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253 | }
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254 | }
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255 | add64le(ptr, val - addr);
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256 | break;
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257 |
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258 | case R_X86_64_GLOB_DAT:
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259 | case R_X86_64_JUMP_SLOT:
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260 | /* They don't need addend */
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261 | write64le(ptr, val - rel->r_addend);
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262 | break;
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263 | case R_X86_64_GOTPCREL:
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264 | case R_X86_64_GOTPCRELX:
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265 | case R_X86_64_REX_GOTPCRELX:
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266 | add32le(ptr, s1->got->sh_addr - addr +
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267 | s1->sym_attrs[sym_index].got_offset - 4);
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268 | break;
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269 | case R_X86_64_GOTPC32:
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270 | add32le(ptr, s1->got->sh_addr - addr + rel->r_addend);
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271 | break;
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272 | case R_X86_64_GOTPC64:
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273 | add64le(ptr, s1->got->sh_addr - addr + rel->r_addend);
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274 | break;
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275 | case R_X86_64_GOTTPOFF:
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276 | add32le(ptr, val - s1->got->sh_addr);
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277 | break;
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278 | case R_X86_64_GOT32:
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279 | /* we load the got offset */
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280 | add32le(ptr, s1->sym_attrs[sym_index].got_offset);
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281 | break;
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282 | case R_X86_64_GOT64:
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283 | /* we load the got offset */
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284 | add64le(ptr, s1->sym_attrs[sym_index].got_offset);
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285 | break;
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286 | case R_X86_64_GOTOFF64:
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287 | add64le(ptr, val - s1->got->sh_addr);
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288 | break;
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289 | case R_X86_64_RELATIVE:
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290 | #ifdef TCC_TARGET_PE
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291 | add32le(ptr, val - s1->pe_imagebase);
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292 | #endif
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293 | /* do nothing */
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294 | break;
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295 | }
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296 | }
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297 |
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298 | #endif /* !TARGET_DEFS_ONLY */
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