1 | /* |
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2 | * Taken from NetBSD and stripped of the relocations not needed on RTEMS. |
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3 | */ |
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4 | |
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5 | /* $NetBSD: mdreloc.c,v 1.43 2010/01/13 20:17:22 christos Exp $ */ |
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6 | |
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7 | /*- |
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8 | * Copyright (c) 1999, 2002 The NetBSD Foundation, Inc. |
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9 | * All rights reserved. |
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10 | * |
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11 | * This code is derived from software contributed to The NetBSD Foundation |
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12 | * by Paul Kranenburg and by Charles M. Hannum. |
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13 | * |
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14 | * Redistribution and use in source and binary forms, with or without |
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15 | * modification, are permitted provided that the following conditions |
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16 | * are met: |
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17 | * 1. Redistributions of source code must retain the above copyright |
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18 | * notice, this list of conditions and the following disclaimer. |
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19 | * 2. Redistributions in binary form must reproduce the above copyright |
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20 | * notice, this list of conditions and the following disclaimer in the |
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21 | * documentation and/or other materials provided with the distribution. |
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22 | * |
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23 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
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24 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
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25 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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26 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
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27 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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28 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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29 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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30 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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31 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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32 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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33 | * POSSIBILITY OF SUCH DAMAGE. |
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34 | */ |
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35 | |
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36 | #include <sys/cdefs.h> |
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37 | |
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38 | #include <inttypes.h> |
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39 | #include <stdio.h> |
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40 | |
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41 | #include <rtems/rtl/rtl.h> |
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42 | #include "rtl-elf.h" |
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43 | #include "rtl-error.h" |
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44 | #include <rtems/rtl/rtl-trace.h> |
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45 | #include "rtl-unwind.h" |
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46 | #include "rtl-unwind-dw2.h" |
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47 | |
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48 | /* |
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49 | * The following table holds for each relocation type: |
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50 | * - the width in bits of the memory location the relocation |
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51 | * applies to (not currently used) |
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52 | * - the number of bits the relocation value must be shifted to the |
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53 | * right (i.e. discard least significant bits) to fit into |
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54 | * the appropriate field in the instruction word. |
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55 | * - flags indicating whether |
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56 | * * the relocation involves a symbol |
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57 | * * the relocation is relative to the current position |
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58 | * * the relocation is for a GOT entry |
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59 | * * the relocation is relative to the load address |
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60 | * |
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61 | */ |
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62 | #define _RF_S 0x80000000 /* Resolve symbol */ |
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63 | #define _RF_A 0x40000000 /* Use addend */ |
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64 | #define _RF_P 0x20000000 /* Location relative */ |
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65 | #define _RF_G 0x10000000 /* GOT offset */ |
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66 | #define _RF_B 0x08000000 /* Load address relative */ |
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67 | #define _RF_U 0x04000000 /* Unaligned */ |
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68 | #define _RF_SZ(s) (((s) & 0xff) << 8) /* memory target size */ |
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69 | #define _RF_RS(s) ( (s) & 0xff) /* right shift */ |
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70 | |
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71 | static const uint32_t reloc_target_flags[] = { |
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72 | 0, /* NONE */ |
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73 | _RF_S|_RF_A| _RF_SZ(8) | _RF_RS(0), /* RELOC_8 */ |
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74 | _RF_S|_RF_A| _RF_SZ(16) | _RF_RS(0), /* RELOC_16 */ |
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75 | _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELOC_32 */ |
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76 | _RF_S|_RF_A|_RF_P| _RF_SZ(8) | _RF_RS(0), /* DISP_8 */ |
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77 | _RF_S|_RF_A|_RF_P| _RF_SZ(16) | _RF_RS(0), /* DISP_16 */ |
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78 | _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* DISP_32 */ |
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79 | _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_30 */ |
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80 | _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_22 */ |
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81 | _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HI22 */ |
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82 | _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 22 */ |
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83 | _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 13 */ |
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84 | _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LO10 */ |
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85 | _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT10 */ |
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86 | _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT13 */ |
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87 | _RF_G| _RF_SZ(32) | _RF_RS(10), /* GOT22 */ |
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88 | _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PC10 */ |
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89 | _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC22 */ |
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90 | _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WPLT30 */ |
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91 | _RF_SZ(32) | _RF_RS(0), /* COPY */ |
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92 | _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_DAT */ |
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93 | _RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */ |
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94 | _RF_A| _RF_B|_RF_SZ(32) | _RF_RS(0), /* RELATIVE */ |
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95 | _RF_S|_RF_A| _RF_U|_RF_SZ(32) | _RF_RS(0), /* UA_32 */ |
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96 | }; |
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97 | |
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98 | #define NOT_CURRENTLY_USED_BUT_MAYBE_USEFUL |
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99 | #ifdef NOT_CURRENTLY_USED_BUT_MAYBE_USEFUL |
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100 | static const char *reloc_names[] = { |
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101 | "NONE", "RELOC_8", "RELOC_16", "RELOC_32", "DISP_8", |
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102 | "DISP_16", "DISP_32", "WDISP_30", "WDISP_22", "HI22", |
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103 | "22", "13", "LO10", "GOT10", "GOT13", |
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104 | "GOT22", "PC10", "PC22", "WPLT30", "COPY", |
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105 | "GLOB_DAT", "JMP_SLOT", "RELATIVE", "UA_32" |
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106 | }; |
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107 | #endif |
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108 | |
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109 | #define RELOC_RESOLVE_SYMBOL(t) ((reloc_target_flags[t] & _RF_S) != 0) |
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110 | #define RELOC_PC_RELATIVE(t) ((reloc_target_flags[t] & _RF_P) != 0) |
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111 | #define RELOC_BASE_RELATIVE(t) ((reloc_target_flags[t] & _RF_B) != 0) |
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112 | #define RELOC_UNALIGNED(t) ((reloc_target_flags[t] & _RF_U) != 0) |
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113 | #define RELOC_USE_ADDEND(t) ((reloc_target_flags[t] & _RF_A) != 0) |
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114 | #define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff) |
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115 | #define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff) |
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116 | |
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117 | static const int reloc_target_bitmask[] = { |
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118 | #define _BM(x) (~(-(1ULL << (x)))) |
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119 | 0, /* NONE */ |
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120 | _BM(8), _BM(16), _BM(32), /* RELOC_8, _16, _32 */ |
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121 | _BM(8), _BM(16), _BM(32), /* DISP8, DISP16, DISP32 */ |
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122 | _BM(30), _BM(22), /* WDISP30, WDISP22 */ |
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123 | _BM(22), _BM(22), /* HI22, _22 */ |
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124 | _BM(13), _BM(10), /* RELOC_13, _LO10 */ |
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125 | _BM(10), _BM(13), _BM(22), /* GOT10, GOT13, GOT22 */ |
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126 | _BM(10), _BM(22), /* _PC10, _PC22 */ |
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127 | _BM(30), 0, /* _WPLT30, _COPY */ |
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128 | -1, -1, -1, /* _GLOB_DAT, JMP_SLOT, _RELATIVE */ |
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129 | _BM(32) /* _UA32 */ |
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130 | #undef _BM |
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131 | }; |
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132 | #define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t]) |
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133 | |
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134 | uint32_t |
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135 | rtems_rtl_elf_section_flags (const rtems_rtl_obj* obj, |
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136 | const Elf_Shdr* shdr) |
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137 | { |
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138 | return 0; |
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139 | } |
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140 | |
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141 | bool |
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142 | rtems_rtl_elf_rel_resolve_sym (Elf_Word type) |
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143 | { |
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144 | return RELOC_RESOLVE_SYMBOL (type) ? true : false; |
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145 | } |
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146 | |
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147 | size_t |
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148 | rtems_rtl_elf_relocate_tramp_max_size (void) |
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149 | { |
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150 | /* |
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151 | * Disable by returning 0. |
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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 | bool |
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157 | rtems_rtl_elf_relocate_rela_tramp (rtems_rtl_obj* obj, |
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158 | const Elf_Rela* rela, |
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159 | const rtems_rtl_obj_sect* sect, |
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160 | const char* symname, |
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161 | const Elf_Byte syminfo, |
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162 | const Elf_Word symvalue) |
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163 | { |
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164 | (void) obj; |
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165 | (void) rela; |
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166 | (void) sect; |
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167 | (void) symname; |
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168 | (void) syminfo; |
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169 | (void) symvalue; |
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170 | return true; |
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171 | } |
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172 | |
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173 | bool |
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174 | rtems_rtl_elf_relocate_rela (rtems_rtl_obj* obj, |
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175 | const Elf_Rela* rela, |
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176 | const rtems_rtl_obj_sect* sect, |
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177 | const char* symname, |
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178 | const Elf_Byte syminfo, |
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179 | const Elf_Word symvalue) |
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180 | { |
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181 | Elf_Addr *where; |
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182 | Elf_Word type, value, mask; |
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183 | Elf_Addr tmp = 0; |
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184 | |
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185 | where = (Elf_Addr *) (sect->base + rela->r_offset); |
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186 | |
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187 | type = ELF_R_TYPE(rela->r_info); |
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188 | if (type == R_TYPE(NONE)) |
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189 | return true; |
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190 | |
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191 | /* We do JMP_SLOTs in _rtld_bind() below */ |
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192 | if (type == R_TYPE(JMP_SLOT)) |
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193 | return true; |
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194 | |
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195 | /* COPY relocs are also handled elsewhere */ |
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196 | if (type == R_TYPE(COPY)) |
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197 | return true; |
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198 | |
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199 | /* |
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200 | * We use the fact that relocation types are an `enum' |
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201 | * Note: R_SPARC_6 is currently numerically largest. |
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202 | */ |
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203 | if (type > R_TYPE(6)) |
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204 | return false; |
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205 | |
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206 | value = rela->r_addend; |
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207 | |
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208 | /* |
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209 | * Handle relative relocs here, as an optimization. |
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210 | */ |
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211 | if (type == R_TYPE (RELATIVE)) { |
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212 | *where += (Elf_Addr)(sect->base + value); |
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213 | if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC)) |
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214 | printf ("rtl: reloc relative in %s --> %p", |
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215 | rtems_rtl_obj_oname (obj), (void *)*where); |
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216 | return true; |
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217 | } |
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218 | |
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219 | if (RELOC_RESOLVE_SYMBOL (type)) { |
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220 | /* Add in the symbol's absolute address */ |
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221 | value += symvalue; |
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222 | } |
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223 | |
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224 | if (RELOC_PC_RELATIVE (type)) { |
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225 | value -= (Elf_Word)where; |
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226 | } |
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227 | |
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228 | if (RELOC_BASE_RELATIVE (type)) { |
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229 | /* |
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230 | * Note that even though sparcs use `Elf_rela' |
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231 | * exclusively we still need the implicit memory addend |
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232 | * in relocations referring to GOT entries. |
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233 | * Undoubtedly, someone f*cked this up in the distant |
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234 | * past, and now we're stuck with it in the name of |
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235 | * compatibility for all eternity.. |
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236 | * |
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237 | * In any case, the implicit and explicit should be |
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238 | * mutually exclusive. We provide a check for that |
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239 | * here. |
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240 | */ |
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241 | #define DIAGNOSTIC |
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242 | #ifdef DIAGNOSTIC |
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243 | if (value != 0 && *where != 0) { |
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244 | if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC)) |
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245 | printf("rtl: reloc base_rel(%s): where=%p, *where 0x%" PRIu32 ", " |
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246 | "addend=0x%" PRIu32 ", base %p\n", |
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247 | rtems_rtl_obj_oname (obj), |
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248 | where, *where, rela->r_addend, sect->base); |
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249 | } |
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250 | #endif |
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251 | value += (Elf_Word)(sect->base + *where); |
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252 | } |
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253 | |
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254 | mask = RELOC_VALUE_BITMASK (type); |
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255 | value >>= RELOC_VALUE_RIGHTSHIFT (type); |
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256 | value &= mask; |
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257 | |
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258 | if (RELOC_UNALIGNED(type)) { |
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259 | /* |
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260 | * Handle unaligned relocations. |
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261 | */ |
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262 | char *ptr = (char*) where; |
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263 | int i, size = RELOC_TARGET_SIZE (type) / 8; |
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264 | |
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265 | /* Read it in one byte at a time. */ |
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266 | for (i = size - 1; i >= 0; i--) |
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267 | tmp = (tmp << 8) | ptr[i]; |
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268 | |
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269 | tmp &= ~mask; |
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270 | tmp |= value; |
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271 | |
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272 | /* Write it back out. */ |
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273 | for (i = size - 1; i >= 0; i--, tmp >>= 8) |
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274 | ptr[i] = tmp & 0xff; |
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275 | } else { |
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276 | *where &= ~mask; |
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277 | *where |= value; |
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278 | tmp = *where; |
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279 | } |
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280 | |
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281 | if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC)) |
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282 | printf ("rtl: %s %p @ %p in %s\n", |
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283 | reloc_names[ELF_R_TYPE(rela->r_info)], |
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284 | (void *)tmp, where, rtems_rtl_obj_oname (obj)); |
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285 | |
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286 | return true; |
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287 | } |
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288 | |
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289 | bool |
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290 | rtems_rtl_elf_relocate_rel_tramp (rtems_rtl_obj* obj, |
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291 | const Elf_Rel* rel, |
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292 | const rtems_rtl_obj_sect* sect, |
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293 | const char* symname, |
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294 | const Elf_Byte syminfo, |
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295 | const Elf_Word symvalue) |
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296 | { |
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297 | (void) obj; |
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298 | (void) rel; |
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299 | (void) sect; |
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300 | (void) symname; |
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301 | (void) syminfo; |
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302 | (void) symvalue; |
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303 | rtems_rtl_set_error (EINVAL, "rel type record not supported"); |
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304 | return false; |
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305 | } |
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306 | |
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307 | bool |
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308 | rtems_rtl_elf_relocate_rel (rtems_rtl_obj* obj, |
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309 | const Elf_Rel* rel, |
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310 | const rtems_rtl_obj_sect* sect, |
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311 | const char* symname, |
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312 | const Elf_Byte syminfo, |
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313 | const Elf_Word symvalue) |
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314 | { |
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315 | (void) obj; |
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316 | (void) rel; |
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317 | (void) sect; |
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318 | (void) symname; |
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319 | (void) syminfo; |
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320 | (void) symvalue; |
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321 | printf ("rtl: rel type record not supported; please report\n"); |
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322 | return false; |
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323 | } |
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324 | |
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325 | bool |
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326 | rtems_rtl_elf_unwind_parse (const rtems_rtl_obj* obj, |
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327 | const char* name, |
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328 | uint32_t flags) |
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329 | { |
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330 | return rtems_rtl_elf_unwind_dw2_parse (obj, name, flags); |
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331 | } |
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332 | |
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333 | bool |
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334 | rtems_rtl_elf_unwind_register (rtems_rtl_obj* obj) |
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335 | { |
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336 | return rtems_rtl_elf_unwind_dw2_register (obj); |
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337 | } |
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338 | |
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339 | bool |
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340 | rtems_rtl_elf_unwind_deregister (rtems_rtl_obj* obj) |
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341 | { |
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342 | return rtems_rtl_elf_unwind_dw2_deregister (obj); |
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343 | } |
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