tools/relocate-rela.c

   1 // SPDX-License-Identifier: GPL-2.0+ OR BSD-2-Clause
   2 /*
   3  * Copyright 2013 Freescale Semiconductor, Inc.
   4  *
   5  * 64-bit and little-endian target only until we need to support a different
   6  * arch that needs this.
   7  */
   8
   9 #include <elf.h>
  10 #include <errno.h>
  11 #include <inttypes.h>
  12 #include <stdarg.h>
  13 #include <stdbool.h>
  14 #include <stdio.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include "compiler.h"
  18
  19 #ifndef R_AARCH64_RELATIVE
  20 #define R_AARCH64_RELATIVE      1027
  21 #endif
  22
  23 static int ei_class;
  24
  25 static uint64_t rela_start, rela_end, text_base;
  26
  27 static const bool debug_en;
  28
  29 static void debug(const char *fmt, ...)
  30 {
  31         va_list args;
  32
  33         if (debug_en) {
  34                 va_start(args, fmt);
  35                 vprintf(fmt, args);
  36                 va_end(args);
  37         }
  38 }
  39
  40 static bool supported_rela(Elf64_Rela *rela)
  41 {
  42         uint64_t mask = 0xffffffffULL; /* would be different on 32-bit */
  43         uint32_t type = rela->r_info & mask;
  44
  45         switch (type) {
  46 #ifdef R_AARCH64_RELATIVE
  47         case R_AARCH64_RELATIVE:
  48                 return true;
  49 #endif
  50         default:
  51                 fprintf(stderr, "warning: unsupported relocation type %"
  52                                 PRIu32 " at %" PRIx64 "\n",
  53                         type, rela->r_offset);
  54
  55                 return false;
  56         }
  57 }
  58
  59 static int decode_elf64(FILE *felf, char **argv)
  60 {
  61         size_t size;
  62         Elf64_Ehdr header;
  63         uint64_t section_header_base, section_header_size, sh_offset, sh_size;
  64         Elf64_Shdr *sh_table; /* Elf symbol table */
  65         int ret, i, machine;
  66         char *sh_str;
  67
  68         debug("64bit version\n");
  69
  70         /* Make sure we are at start */
  71         rewind(felf);
  72
  73         size = fread(&header, 1, sizeof(header), felf);
  74         if (size != sizeof(header)) {
  75                 fclose(felf);
  76                 return 25;
  77         }
  78
  79         machine = header.e_machine;
  80         debug("Machine\t%d\n", machine);
  81
  82         text_base = header.e_entry;
  83         section_header_base = header.e_shoff;
  84         section_header_size = header.e_shentsize * header.e_shnum;
  85
  86         sh_table = malloc(section_header_size);
  87         if (!sh_table) {
  88                 fprintf(stderr, "%s: Cannot allocate space for section header\n",
  89                         argv[0]);
  90                 fclose(felf);
  91                 return 26;
  92         }
  93
  94         ret = fseek(felf, section_header_base, SEEK_SET);
  95         if (ret) {
  96                 fprintf(stderr, "%s: Can't set pointer to section header: %x/%lx\n",
  97                         argv[0], ret, section_header_base);
  98                 free(sh_table);
  99                 fclose(felf);
 100                 return 26;
 101         }
 102
 103         size = fread(sh_table, 1, section_header_size, felf);
 104         if (size != section_header_size) {
 105                 fprintf(stderr, "%s: Can't read section header: %lx/%lx\n",
 106                         argv[0], size, section_header_size);
 107                 free(sh_table);
 108                 fclose(felf);
 109                 return 27;
 110         }
 111
 112         sh_size = sh_table[header.e_shstrndx].sh_size;
 113         debug("e_shstrndx\t0x%08x\n", header.e_shstrndx);
 114         debug("sh_size\t\t0x%08lx\n", sh_size);
 115
 116         sh_str = malloc(sh_size);
 117         if (!sh_str) {
 118                 fprintf(stderr, "malloc failed\n");
 119                 free(sh_table);
 120                 fclose(felf);
 121                 return 28;
 122         }
 123
 124         /*
 125          * Specifies the byte offset from the beginning of the file
 126          * to the first byte in the section.
 127          */
 128         sh_offset = sh_table[header.e_shstrndx].sh_offset;
 129
 130         debug("sh_offset\t0x%08x\n", header.e_shnum);
 131
 132         ret = fseek(felf, sh_offset, SEEK_SET);
 133         if (ret) {
 134                 fprintf(stderr, "Setting up sh_offset failed\n");
 135                 free(sh_str);
 136                 free(sh_table);
 137                 fclose(felf);
 138                 return 29;
 139         }
 140
 141         size = fread(sh_str, 1, sh_size, felf);
 142         if (size != sh_size) {
 143                 fprintf(stderr, "%s: Can't read section: %lx/%lx\n",
 144                         argv[0], size, sh_size);
 145                 free(sh_str);
 146                 free(sh_table);
 147                 fclose(felf);
 148                 return 30;
 149         }
 150
 151         for (i = 0; i < header.e_shnum; i++) {
 152                 /* fprintf(stderr, "%s\n", sh_str + sh_table[i].sh_name); Debug only */
 153                 if (!strcmp(".rela.dyn", (sh_str + sh_table[i].sh_name))) {
 154                         debug("Found section\t\".rela_dyn\"\n");
 155                         debug(" at addr\t0x%08x\n",
 156                               (unsigned int)sh_table[i].sh_addr);
 157                         debug(" at offset\t0x%08x\n",
 158                               (unsigned int)sh_table[i].sh_offset);
 159                         debug(" of size\t0x%08x\n",
 160                               (unsigned int)sh_table[i].sh_size);
 161                         rela_start = sh_table[i].sh_addr;
 162                         rela_end = rela_start + sh_table[i].sh_size;
 163                         break;
 164                 }
 165         }
 166
 167         /* Clean up */
 168         free(sh_str);
 169         free(sh_table);
 170         fclose(felf);
 171
 172         debug("text_base\t0x%08lx\n", text_base);
 173         debug("rela_start\t0x%08lx\n", rela_start);
 174         debug("rela_end\t0x%08lx\n", rela_end);
 175
 176         if (!rela_start)
 177                 return 1;
 178
 179         return 0;
 180 }
 181
 182 static int decode_elf(char **argv)
 183 {
 184         FILE *felf;
 185         size_t size;
 186         unsigned char e_ident[EI_NIDENT];
 187
 188         felf = fopen(argv[2], "r+b");
 189         if (!felf) {
 190                 fprintf(stderr, "%s: Cannot open %s: %s\n",
 191                         argv[0], argv[5], strerror(errno));
 192                 return 2;
 193         }
 194
 195         size = fread(e_ident, 1, EI_NIDENT, felf);
 196         if (size != EI_NIDENT) {
 197                 fclose(felf);
 198                 return 25;
 199         }
 200
 201         /* Check if this is really ELF file */
 202         if (e_ident[0] != 0x7f &&
 203             e_ident[1] != 'E' &&
 204             e_ident[2] != 'L' &&
 205             e_ident[3] != 'F') {
 206                 fclose(felf);
 207                 return 1;
 208         }
 209
 210         ei_class = e_ident[4];
 211         debug("EI_CLASS(1=32bit, 2=64bit) %d\n", ei_class);
 212
 213         if (ei_class == 2)
 214                 return decode_elf64(felf, argv);
 215
 216         return 1;
 217 }
 218
 219 int main(int argc, char **argv)
 220 {
 221         FILE *f;
 222         int i, num, ret;
 223         uint64_t file_size;
 224
 225         if (argc != 3) {
 226                 fprintf(stderr, "Statically apply ELF rela relocations\n");
 227                 fprintf(stderr, "Usage: %s <bin file> <u-boot ELF>\n",
 228                         argv[0]);
 229                 return 1;
 230         }
 231
 232         ret = decode_elf(argv);
 233         if (ret) {
 234                 fprintf(stderr, "ELF decoding failed\n");
 235                 return ret;
 236         }
 237
 238         if (rela_start > rela_end || rela_start < text_base) {
 239                 fprintf(stderr, "%s: bad rela bounds\n", argv[0]);
 240                 return 3;
 241         }
 242
 243         rela_start -= text_base;
 244         rela_end -= text_base;
 245
 246         f = fopen(argv[1], "r+b");
 247         if (!f) {
 248                 fprintf(stderr, "%s: Cannot open %s: %s\n",
 249                         argv[0], argv[1], strerror(errno));
 250                 return 2;
 251         }
 252
 253         fseek(f, 0, SEEK_END);
 254         file_size = ftell(f);
 255         rewind(f);
 256
 257         if (rela_end > file_size) {
 258                 // Most likely compiler inserted some section that didn't get
 259                 // objcopy-ed into the final binary
 260                 rela_end = file_size;
 261         }
 262
 263         if ((rela_end - rela_start) % sizeof(Elf64_Rela)) {
 264                 fprintf(stderr, "%s: rela size isn't a multiple of Elf64_Rela\n", argv[0]);
 265                 return 3;
 266         }
 267
 268         num = (rela_end - rela_start) / sizeof(Elf64_Rela);
 269
 270         for (i = 0; i < num; i++) {
 271                 Elf64_Rela rela, swrela;
 272                 uint64_t pos = rela_start + sizeof(Elf64_Rela) * i;
 273                 uint64_t addr;
 274
 275                 if (fseek(f, pos, SEEK_SET) < 0) {
 276                         fprintf(stderr, "%s: %s: seek to %" PRIx64
 277                                         " failed: %s\n",
 278                                 argv[0], argv[1], pos, strerror(errno));
 279                 }
 280
 281                 if (fread(&rela, sizeof(rela), 1, f) != 1) {
 282                         fprintf(stderr, "%s: %s: read rela failed at %"
 283                                         PRIx64 "\n",
 284                                 argv[0], argv[1], pos);
 285                         return 4;
 286                 }
 287
 288                 swrela.r_offset = cpu_to_le64(rela.r_offset);
 289                 swrela.r_info = cpu_to_le64(rela.r_info);
 290                 swrela.r_addend = cpu_to_le64(rela.r_addend);
 291
 292                 if (!supported_rela(&swrela))
 293                         continue;
 294
 295                 debug("Rela %" PRIx64 " %" PRIu64 " %" PRIx64 "\n",
 296                       swrela.r_offset, swrela.r_info, swrela.r_addend);
 297
 298                 if (swrela.r_offset < text_base) {
 299                         fprintf(stderr, "%s: %s: bad rela at %" PRIx64 "\n",
 300                                 argv[0], argv[1], pos);
 301                         return 4;
 302                 }
 303
 304                 addr = swrela.r_offset - text_base;
 305
 306                 if (fseek(f, addr, SEEK_SET) < 0) {
 307                         fprintf(stderr, "%s: %s: seek to %"
 308                                         PRIx64 " failed: %s\n",
 309                                 argv[0], argv[1], addr, strerror(errno));
 310                 }
 311
 312                 if (fwrite(&rela.r_addend, sizeof(rela.r_addend), 1, f) != 1) {
 313                         fprintf(stderr, "%s: %s: write failed at %" PRIx64 "\n",
 314                                 argv[0], argv[1], addr);
 315                         return 4;
 316                 }
 317         }
 318
 319         if (fclose(f) < 0) {
 320                 fprintf(stderr, "%s: %s: close failed: %s\n",
 321                         argv[0], argv[1], strerror(errno));
 322                 return 4;
 323         }
 324
 325         return 0;
 326 }