1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * MIPS Relocation Data Generator 4 * 5 * Copyright (c) 2017 Imagination Technologies Ltd. 6 */ 7 8 #include <assert.h> 9 #include <elf.h> 10 #include <errno.h> 11 #include <fcntl.h> 12 #include <limits.h> 13 #include <stdbool.h> 14 #include <stdio.h> 15 #include <stdlib.h> 16 #include <sys/mman.h> 17 #include <sys/stat.h> 18 #include <unistd.h> 19 20 #include <asm/relocs.h> 21 22 #define hdr_field(pfx, idx, field) ({ \ 23 uint64_t _val; \ 24 unsigned int _size; \ 25 \ 26 if (is_64) { \ 27 _val = pfx##hdr64[idx].field; \ 28 _size = sizeof(pfx##hdr64[0].field); \ 29 } else { \ 30 _val = pfx##hdr32[idx].field; \ 31 _size = sizeof(pfx##hdr32[0].field); \ 32 } \ 33 \ 34 switch (_size) { \ 35 case 1: \ 36 break; \ 37 case 2: \ 38 _val = is_be ? be16toh(_val) : le16toh(_val); \ 39 break; \ 40 case 4: \ 41 _val = is_be ? be32toh(_val) : le32toh(_val); \ 42 break; \ 43 case 8: \ 44 _val = is_be ? be64toh(_val) : le64toh(_val); \ 45 break; \ 46 } \ 47 \ 48 _val; \ 49 }) 50 51 #define set_hdr_field(pfx, idx, field, val) ({ \ 52 uint64_t _val; \ 53 unsigned int _size; \ 54 \ 55 if (is_64) \ 56 _size = sizeof(pfx##hdr64[0].field); \ 57 else \ 58 _size = sizeof(pfx##hdr32[0].field); \ 59 \ 60 switch (_size) { \ 61 case 1: \ 62 _val = val; \ 63 break; \ 64 case 2: \ 65 _val = is_be ? htobe16(val) : htole16(val); \ 66 break; \ 67 case 4: \ 68 _val = is_be ? htobe32(val) : htole32(val); \ 69 break; \ 70 case 8: \ 71 _val = is_be ? htobe64(val) : htole64(val); \ 72 break; \ 73 default: \ 74 /* We should never reach here */ \ 75 _val = 0; \ 76 assert(0); \ 77 break; \ 78 } \ 79 \ 80 if (is_64) \ 81 pfx##hdr64[idx].field = _val; \ 82 else \ 83 pfx##hdr32[idx].field = _val; \ 84 }) 85 86 #define ehdr_field(field) \ 87 hdr_field(e, 0, field) 88 #define phdr_field(idx, field) \ 89 hdr_field(p, idx, field) 90 #define shdr_field(idx, field) \ 91 hdr_field(s, idx, field) 92 93 #define set_phdr_field(idx, field, val) \ 94 set_hdr_field(p, idx, field, val) 95 #define set_shdr_field(idx, field, val) \ 96 set_hdr_field(s, idx, field, val) 97 98 #define shstr(idx) (&shstrtab[idx]) 99 100 bool is_64, is_be; 101 uint64_t text_base; 102 103 struct mips_reloc { 104 uint8_t type; 105 uint64_t offset; 106 } *relocs; 107 size_t relocs_sz, relocs_idx; 108 109 static int add_reloc(unsigned int type, uint64_t off) 110 { 111 struct mips_reloc *new; 112 size_t new_sz; 113 114 switch (type) { 115 case R_MIPS_NONE: 116 case R_MIPS_LO16: 117 case R_MIPS_PC16: 118 case R_MIPS_HIGHER: 119 case R_MIPS_HIGHEST: 120 case R_MIPS_PC21_S2: 121 case R_MIPS_PC26_S2: 122 /* Skip these relocs */ 123 return 0; 124 125 default: 126 break; 127 } 128 129 if (relocs_idx == relocs_sz) { 130 new_sz = relocs_sz ? relocs_sz * 2 : 128; 131 new = realloc(relocs, new_sz * sizeof(*relocs)); 132 if (!new) { 133 fprintf(stderr, "Out of memory\n"); 134 return -ENOMEM; 135 } 136 137 relocs = new; 138 relocs_sz = new_sz; 139 } 140 141 relocs[relocs_idx++] = (struct mips_reloc){ 142 .type = type, 143 .offset = off, 144 }; 145 146 return 0; 147 } 148 149 static int parse_mips32_rel(const void *_rel) 150 { 151 const Elf32_Rel *rel = _rel; 152 uint32_t off, type; 153 154 off = is_be ? be32toh(rel->r_offset) : le32toh(rel->r_offset); 155 off -= text_base; 156 157 type = is_be ? be32toh(rel->r_info) : le32toh(rel->r_info); 158 type = ELF32_R_TYPE(type); 159 160 return add_reloc(type, off); 161 } 162 163 static int parse_mips64_rela(const void *_rel) 164 { 165 const Elf64_Rela *rel = _rel; 166 uint64_t off, type; 167 168 off = is_be ? be64toh(rel->r_offset) : le64toh(rel->r_offset); 169 off -= text_base; 170 171 type = rel->r_info >> (64 - 8); 172 173 return add_reloc(type, off); 174 } 175 176 static void output_uint(uint8_t **buf, uint64_t val) 177 { 178 uint64_t tmp; 179 180 do { 181 tmp = val & 0x7f; 182 val >>= 7; 183 tmp |= !!val << 7; 184 *(*buf)++ = tmp; 185 } while (val); 186 } 187 188 static int compare_relocs(const void *a, const void *b) 189 { 190 const struct mips_reloc *ra = a, *rb = b; 191 192 return ra->offset - rb->offset; 193 } 194 195 int main(int argc, char *argv[]) 196 { 197 unsigned int i, j, i_rel_shdr, sh_type, sh_entsize, sh_entries; 198 size_t rel_size, rel_actual_size; 199 const char *shstrtab, *sh_name, *rel_pfx; 200 int (*parse_fn)(const void *rel); 201 uint8_t *buf_start, *buf; 202 const Elf32_Ehdr *ehdr32; 203 const Elf64_Ehdr *ehdr64; 204 uintptr_t sh_offset; 205 Elf32_Shdr *shdr32; 206 Elf64_Shdr *shdr64; 207 struct stat st; 208 int err, fd; 209 void *elf; 210 bool skip; 211 212 fd = open(argv[1], O_RDWR); 213 if (fd == -1) { 214 fprintf(stderr, "Unable to open input file %s\n", argv[1]); 215 err = errno; 216 goto out_ret; 217 } 218 219 err = fstat(fd, &st); 220 if (err) { 221 fprintf(stderr, "Unable to fstat() input file\n"); 222 goto out_close_fd; 223 } 224 225 elf = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); 226 if (elf == MAP_FAILED) { 227 fprintf(stderr, "Unable to mmap() input file\n"); 228 err = errno; 229 goto out_close_fd; 230 } 231 232 ehdr32 = elf; 233 ehdr64 = elf; 234 235 if (memcmp(&ehdr32->e_ident[EI_MAG0], ELFMAG, SELFMAG)) { 236 fprintf(stderr, "Input file is not an ELF\n"); 237 err = -EINVAL; 238 goto out_free_relocs; 239 } 240 241 if (ehdr32->e_ident[EI_VERSION] != EV_CURRENT) { 242 fprintf(stderr, "Unrecognised ELF version\n"); 243 err = -EINVAL; 244 goto out_free_relocs; 245 } 246 247 switch (ehdr32->e_ident[EI_CLASS]) { 248 case ELFCLASS32: 249 is_64 = false; 250 break; 251 case ELFCLASS64: 252 is_64 = true; 253 break; 254 default: 255 fprintf(stderr, "Unrecognised ELF class\n"); 256 err = -EINVAL; 257 goto out_free_relocs; 258 } 259 260 switch (ehdr32->e_ident[EI_DATA]) { 261 case ELFDATA2LSB: 262 is_be = false; 263 break; 264 case ELFDATA2MSB: 265 is_be = true; 266 break; 267 default: 268 fprintf(stderr, "Unrecognised ELF data encoding\n"); 269 err = -EINVAL; 270 goto out_free_relocs; 271 } 272 273 if (ehdr_field(e_type) != ET_EXEC) { 274 fprintf(stderr, "Input ELF is not an executable\n"); 275 printf("type 0x%lx\n", ehdr_field(e_type)); 276 err = -EINVAL; 277 goto out_free_relocs; 278 } 279 280 if (ehdr_field(e_machine) != EM_MIPS) { 281 fprintf(stderr, "Input ELF does not target MIPS\n"); 282 err = -EINVAL; 283 goto out_free_relocs; 284 } 285 286 shdr32 = elf + ehdr_field(e_shoff); 287 shdr64 = elf + ehdr_field(e_shoff); 288 shstrtab = elf + shdr_field(ehdr_field(e_shstrndx), sh_offset); 289 290 i_rel_shdr = UINT_MAX; 291 for (i = 0; i < ehdr_field(e_shnum); i++) { 292 sh_name = shstr(shdr_field(i, sh_name)); 293 294 if (!strcmp(sh_name, ".data.reloc")) { 295 i_rel_shdr = i; 296 continue; 297 } 298 299 if (!strcmp(sh_name, ".text")) { 300 text_base = shdr_field(i, sh_addr); 301 continue; 302 } 303 } 304 if (i_rel_shdr == UINT_MAX) { 305 fprintf(stderr, "Unable to find .rel section\n"); 306 err = -EINVAL; 307 goto out_free_relocs; 308 } 309 if (!text_base) { 310 fprintf(stderr, "Unable to find .text base address\n"); 311 err = -EINVAL; 312 goto out_free_relocs; 313 } 314 315 rel_pfx = is_64 ? ".rela." : ".rel."; 316 317 for (i = 0; i < ehdr_field(e_shnum); i++) { 318 sh_type = shdr_field(i, sh_type); 319 if ((sh_type != SHT_REL) && (sh_type != SHT_RELA)) 320 continue; 321 322 sh_name = shstr(shdr_field(i, sh_name)); 323 if (strncmp(sh_name, rel_pfx, strlen(rel_pfx))) { 324 if (strcmp(sh_name, ".rel") && strcmp(sh_name, ".rel.dyn")) 325 fprintf(stderr, "WARNING: Unexpected reloc section name '%s'\n", sh_name); 326 continue; 327 } 328 329 /* 330 * Skip reloc sections which either don't correspond to another 331 * section in the ELF, or whose corresponding section isn't 332 * loaded as part of the U-Boot binary (ie. doesn't have the 333 * alloc flags set). 334 */ 335 skip = true; 336 for (j = 0; j < ehdr_field(e_shnum); j++) { 337 if (strcmp(&sh_name[strlen(rel_pfx) - 1], shstr(shdr_field(j, sh_name)))) 338 continue; 339 340 skip = !(shdr_field(j, sh_flags) & SHF_ALLOC); 341 break; 342 } 343 if (skip) 344 continue; 345 346 sh_offset = shdr_field(i, sh_offset); 347 sh_entsize = shdr_field(i, sh_entsize); 348 sh_entries = shdr_field(i, sh_size) / sh_entsize; 349 350 if (sh_type == SHT_REL) { 351 if (is_64) { 352 fprintf(stderr, "REL-style reloc in MIPS64 ELF?\n"); 353 err = -EINVAL; 354 goto out_free_relocs; 355 } else { 356 parse_fn = parse_mips32_rel; 357 } 358 } else { 359 if (is_64) { 360 parse_fn = parse_mips64_rela; 361 } else { 362 fprintf(stderr, "RELA-style reloc in MIPS32 ELF?\n"); 363 err = -EINVAL; 364 goto out_free_relocs; 365 } 366 } 367 368 for (j = 0; j < sh_entries; j++) { 369 err = parse_fn(elf + sh_offset + (j * sh_entsize)); 370 if (err) 371 goto out_free_relocs; 372 } 373 } 374 375 /* Sort relocs in ascending order of offset */ 376 qsort(relocs, relocs_idx, sizeof(*relocs), compare_relocs); 377 378 /* Make reloc offsets relative to their predecessor */ 379 for (i = relocs_idx - 1; i > 0; i--) 380 relocs[i].offset -= relocs[i - 1].offset; 381 382 /* Write the relocations to the .rel section */ 383 buf = buf_start = elf + shdr_field(i_rel_shdr, sh_offset); 384 for (i = 0; i < relocs_idx; i++) { 385 output_uint(&buf, relocs[i].type); 386 output_uint(&buf, relocs[i].offset >> 2); 387 } 388 389 /* Write a terminating R_MIPS_NONE (0) */ 390 output_uint(&buf, R_MIPS_NONE); 391 392 /* Ensure the relocs didn't overflow the .rel section */ 393 rel_size = shdr_field(i_rel_shdr, sh_size); 394 rel_actual_size = buf - buf_start; 395 if (rel_actual_size > rel_size) { 396 fprintf(stderr, "Relocations overflow available space of 0x%lx (required 0x%lx)!\n", 397 rel_size, rel_actual_size); 398 fprintf(stderr, "Please adjust CONFIG_MIPS_RELOCATION_TABLE_SIZE to at least 0x%lx\n", 399 (rel_actual_size + 0x100) & ~0xFF); 400 err = -ENOMEM; 401 goto out_free_relocs; 402 } 403 404 /* Make sure data is written back to the file */ 405 err = msync(elf, st.st_size, MS_SYNC); 406 if (err) { 407 fprintf(stderr, "Failed to msync: %d\n", errno); 408 goto out_free_relocs; 409 } 410 411 out_free_relocs: 412 free(relocs); 413 munmap(elf, st.st_size); 414 out_close_fd: 415 close(fd); 416 out_ret: 417 return err; 418 } 419