1 /* 2 * IA-64-specific support for kernel module loader. 3 * 4 * Copyright (C) 2003 Hewlett-Packard Co 5 * David Mosberger-Tang <davidm@hpl.hp.com> 6 * 7 * Loosely based on patch by Rusty Russell. 8 */ 9 10 /* relocs tested so far: 11 12 DIR64LSB 13 FPTR64LSB 14 GPREL22 15 LDXMOV 16 LDXMOV 17 LTOFF22 18 LTOFF22X 19 LTOFF22X 20 LTOFF_FPTR22 21 PCREL21B (for br.call only; br.cond is not supported out of modules!) 22 PCREL60B (for brl.cond only; brl.call is not supported for modules!) 23 PCREL64LSB 24 SECREL32LSB 25 SEGREL64LSB 26 */ 27 28 29 #include <linux/kernel.h> 30 #include <linux/sched.h> 31 #include <linux/elf.h> 32 #include <linux/moduleloader.h> 33 #include <linux/string.h> 34 #include <linux/vmalloc.h> 35 36 #include <asm/patch.h> 37 #include <asm/unaligned.h> 38 39 #define ARCH_MODULE_DEBUG 0 40 41 #if ARCH_MODULE_DEBUG 42 # define DEBUGP printk 43 # define inline 44 #else 45 # define DEBUGP(fmt , a...) 46 #endif 47 48 #ifdef CONFIG_ITANIUM 49 # define USE_BRL 0 50 #else 51 # define USE_BRL 1 52 #endif 53 54 #define MAX_LTOFF ((uint64_t) (1 << 22)) /* max. allowable linkage-table offset */ 55 56 /* Define some relocation helper macros/types: */ 57 58 #define FORMAT_SHIFT 0 59 #define FORMAT_BITS 3 60 #define FORMAT_MASK ((1 << FORMAT_BITS) - 1) 61 #define VALUE_SHIFT 3 62 #define VALUE_BITS 5 63 #define VALUE_MASK ((1 << VALUE_BITS) - 1) 64 65 enum reloc_target_format { 66 /* direct encoded formats: */ 67 RF_NONE = 0, 68 RF_INSN14 = 1, 69 RF_INSN22 = 2, 70 RF_INSN64 = 3, 71 RF_32MSB = 4, 72 RF_32LSB = 5, 73 RF_64MSB = 6, 74 RF_64LSB = 7, 75 76 /* formats that cannot be directly decoded: */ 77 RF_INSN60, 78 RF_INSN21B, /* imm21 form 1 */ 79 RF_INSN21M, /* imm21 form 2 */ 80 RF_INSN21F /* imm21 form 3 */ 81 }; 82 83 enum reloc_value_formula { 84 RV_DIRECT = 4, /* S + A */ 85 RV_GPREL = 5, /* @gprel(S + A) */ 86 RV_LTREL = 6, /* @ltoff(S + A) */ 87 RV_PLTREL = 7, /* @pltoff(S + A) */ 88 RV_FPTR = 8, /* @fptr(S + A) */ 89 RV_PCREL = 9, /* S + A - P */ 90 RV_LTREL_FPTR = 10, /* @ltoff(@fptr(S + A)) */ 91 RV_SEGREL = 11, /* @segrel(S + A) */ 92 RV_SECREL = 12, /* @secrel(S + A) */ 93 RV_BDREL = 13, /* BD + A */ 94 RV_LTV = 14, /* S + A (like RV_DIRECT, except frozen at static link-time) */ 95 RV_PCREL2 = 15, /* S + A - P */ 96 RV_SPECIAL = 16, /* various (see below) */ 97 RV_RSVD17 = 17, 98 RV_TPREL = 18, /* @tprel(S + A) */ 99 RV_LTREL_TPREL = 19, /* @ltoff(@tprel(S + A)) */ 100 RV_DTPMOD = 20, /* @dtpmod(S + A) */ 101 RV_LTREL_DTPMOD = 21, /* @ltoff(@dtpmod(S + A)) */ 102 RV_DTPREL = 22, /* @dtprel(S + A) */ 103 RV_LTREL_DTPREL = 23, /* @ltoff(@dtprel(S + A)) */ 104 RV_RSVD24 = 24, 105 RV_RSVD25 = 25, 106 RV_RSVD26 = 26, 107 RV_RSVD27 = 27 108 /* 28-31 reserved for implementation-specific purposes. */ 109 }; 110 111 #define N(reloc) [R_IA64_##reloc] = #reloc 112 113 static const char *reloc_name[256] = { 114 N(NONE), N(IMM14), N(IMM22), N(IMM64), 115 N(DIR32MSB), N(DIR32LSB), N(DIR64MSB), N(DIR64LSB), 116 N(GPREL22), N(GPREL64I), N(GPREL32MSB), N(GPREL32LSB), 117 N(GPREL64MSB), N(GPREL64LSB), N(LTOFF22), N(LTOFF64I), 118 N(PLTOFF22), N(PLTOFF64I), N(PLTOFF64MSB), N(PLTOFF64LSB), 119 N(FPTR64I), N(FPTR32MSB), N(FPTR32LSB), N(FPTR64MSB), 120 N(FPTR64LSB), N(PCREL60B), N(PCREL21B), N(PCREL21M), 121 N(PCREL21F), N(PCREL32MSB), N(PCREL32LSB), N(PCREL64MSB), 122 N(PCREL64LSB), N(LTOFF_FPTR22), N(LTOFF_FPTR64I), N(LTOFF_FPTR32MSB), 123 N(LTOFF_FPTR32LSB), N(LTOFF_FPTR64MSB), N(LTOFF_FPTR64LSB), N(SEGREL32MSB), 124 N(SEGREL32LSB), N(SEGREL64MSB), N(SEGREL64LSB), N(SECREL32MSB), 125 N(SECREL32LSB), N(SECREL64MSB), N(SECREL64LSB), N(REL32MSB), 126 N(REL32LSB), N(REL64MSB), N(REL64LSB), N(LTV32MSB), 127 N(LTV32LSB), N(LTV64MSB), N(LTV64LSB), N(PCREL21BI), 128 N(PCREL22), N(PCREL64I), N(IPLTMSB), N(IPLTLSB), 129 N(COPY), N(LTOFF22X), N(LDXMOV), N(TPREL14), 130 N(TPREL22), N(TPREL64I), N(TPREL64MSB), N(TPREL64LSB), 131 N(LTOFF_TPREL22), N(DTPMOD64MSB), N(DTPMOD64LSB), N(LTOFF_DTPMOD22), 132 N(DTPREL14), N(DTPREL22), N(DTPREL64I), N(DTPREL32MSB), 133 N(DTPREL32LSB), N(DTPREL64MSB), N(DTPREL64LSB), N(LTOFF_DTPREL22) 134 }; 135 136 #undef N 137 138 /* Opaque struct for insns, to protect against derefs. */ 139 struct insn; 140 141 static inline uint64_t 142 bundle (const struct insn *insn) 143 { 144 return (uint64_t) insn & ~0xfUL; 145 } 146 147 static inline int 148 slot (const struct insn *insn) 149 { 150 return (uint64_t) insn & 0x3; 151 } 152 153 static int 154 apply_imm64 (struct module *mod, struct insn *insn, uint64_t val) 155 { 156 if (slot(insn) != 2) { 157 printk(KERN_ERR "%s: invalid slot number %d for IMM64\n", 158 mod->name, slot(insn)); 159 return 0; 160 } 161 ia64_patch_imm64((u64) insn, val); 162 return 1; 163 } 164 165 static int 166 apply_imm60 (struct module *mod, struct insn *insn, uint64_t val) 167 { 168 if (slot(insn) != 2) { 169 printk(KERN_ERR "%s: invalid slot number %d for IMM60\n", 170 mod->name, slot(insn)); 171 return 0; 172 } 173 if (val + ((uint64_t) 1 << 59) >= (1UL << 60)) { 174 printk(KERN_ERR "%s: value %ld out of IMM60 range\n", mod->name, (int64_t) val); 175 return 0; 176 } 177 ia64_patch_imm60((u64) insn, val); 178 return 1; 179 } 180 181 static int 182 apply_imm22 (struct module *mod, struct insn *insn, uint64_t val) 183 { 184 if (val + (1 << 21) >= (1 << 22)) { 185 printk(KERN_ERR "%s: value %li out of IMM22 range\n", mod->name, (int64_t)val); 186 return 0; 187 } 188 ia64_patch((u64) insn, 0x01fffcfe000UL, ( ((val & 0x200000UL) << 15) /* bit 21 -> 36 */ 189 | ((val & 0x1f0000UL) << 6) /* bit 16 -> 22 */ 190 | ((val & 0x00ff80UL) << 20) /* bit 7 -> 27 */ 191 | ((val & 0x00007fUL) << 13) /* bit 0 -> 13 */)); 192 return 1; 193 } 194 195 static int 196 apply_imm21b (struct module *mod, struct insn *insn, uint64_t val) 197 { 198 if (val + (1 << 20) >= (1 << 21)) { 199 printk(KERN_ERR "%s: value %li out of IMM21b range\n", mod->name, (int64_t)val); 200 return 0; 201 } 202 ia64_patch((u64) insn, 0x11ffffe000UL, ( ((val & 0x100000UL) << 16) /* bit 20 -> 36 */ 203 | ((val & 0x0fffffUL) << 13) /* bit 0 -> 13 */)); 204 return 1; 205 } 206 207 #if USE_BRL 208 209 struct plt_entry { 210 /* Three instruction bundles in PLT. */ 211 unsigned char bundle[2][16]; 212 }; 213 214 static const struct plt_entry ia64_plt_template = { 215 { 216 { 217 0x04, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */ 218 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, /* movl gp=TARGET_GP */ 219 0x00, 0x00, 0x00, 0x60 220 }, 221 { 222 0x05, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */ 223 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* brl.many gp=TARGET_GP */ 224 0x08, 0x00, 0x00, 0xc0 225 } 226 } 227 }; 228 229 static int 230 patch_plt (struct module *mod, struct plt_entry *plt, long target_ip, unsigned long target_gp) 231 { 232 if (apply_imm64(mod, (struct insn *) (plt->bundle[0] + 2), target_gp) 233 && apply_imm60(mod, (struct insn *) (plt->bundle[1] + 2), 234 (target_ip - (int64_t) plt->bundle[1]) / 16)) 235 return 1; 236 return 0; 237 } 238 239 unsigned long 240 plt_target (struct plt_entry *plt) 241 { 242 uint64_t b0, b1, *b = (uint64_t *) plt->bundle[1]; 243 long off; 244 245 b0 = b[0]; b1 = b[1]; 246 off = ( ((b1 & 0x00fffff000000000UL) >> 36) /* imm20b -> bit 0 */ 247 | ((b0 >> 48) << 20) | ((b1 & 0x7fffffUL) << 36) /* imm39 -> bit 20 */ 248 | ((b1 & 0x0800000000000000UL) << 0)); /* i -> bit 59 */ 249 return (long) plt->bundle[1] + 16*off; 250 } 251 252 #else /* !USE_BRL */ 253 254 struct plt_entry { 255 /* Three instruction bundles in PLT. */ 256 unsigned char bundle[3][16]; 257 }; 258 259 static const struct plt_entry ia64_plt_template = { 260 { 261 { 262 0x05, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */ 263 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* movl r16=TARGET_IP */ 264 0x02, 0x00, 0x00, 0x60 265 }, 266 { 267 0x04, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */ 268 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, /* movl gp=TARGET_GP */ 269 0x00, 0x00, 0x00, 0x60 270 }, 271 { 272 0x11, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MIB] nop.m 0 */ 273 0x60, 0x80, 0x04, 0x80, 0x03, 0x00, /* mov b6=r16 */ 274 0x60, 0x00, 0x80, 0x00 /* br.few b6 */ 275 } 276 } 277 }; 278 279 static int 280 patch_plt (struct module *mod, struct plt_entry *plt, long target_ip, unsigned long target_gp) 281 { 282 if (apply_imm64(mod, (struct insn *) (plt->bundle[0] + 2), target_ip) 283 && apply_imm64(mod, (struct insn *) (plt->bundle[1] + 2), target_gp)) 284 return 1; 285 return 0; 286 } 287 288 unsigned long 289 plt_target (struct plt_entry *plt) 290 { 291 uint64_t b0, b1, *b = (uint64_t *) plt->bundle[0]; 292 293 b0 = b[0]; b1 = b[1]; 294 return ( ((b1 & 0x000007f000000000) >> 36) /* imm7b -> bit 0 */ 295 | ((b1 & 0x07fc000000000000) >> 43) /* imm9d -> bit 7 */ 296 | ((b1 & 0x0003e00000000000) >> 29) /* imm5c -> bit 16 */ 297 | ((b1 & 0x0000100000000000) >> 23) /* ic -> bit 21 */ 298 | ((b0 >> 46) << 22) | ((b1 & 0x7fffff) << 40) /* imm41 -> bit 22 */ 299 | ((b1 & 0x0800000000000000) << 4)); /* i -> bit 63 */ 300 } 301 302 #endif /* !USE_BRL */ 303 304 void * 305 module_alloc (unsigned long size) 306 { 307 if (!size) 308 return NULL; 309 return vmalloc(size); 310 } 311 312 void 313 module_free (struct module *mod, void *module_region) 314 { 315 if (mod && mod->arch.init_unw_table && 316 module_region == mod->module_init) { 317 unw_remove_unwind_table(mod->arch.init_unw_table); 318 mod->arch.init_unw_table = NULL; 319 } 320 vfree(module_region); 321 } 322 323 /* Have we already seen one of these relocations? */ 324 /* FIXME: we could look in other sections, too --RR */ 325 static int 326 duplicate_reloc (const Elf64_Rela *rela, unsigned int num) 327 { 328 unsigned int i; 329 330 for (i = 0; i < num; i++) { 331 if (rela[i].r_info == rela[num].r_info && rela[i].r_addend == rela[num].r_addend) 332 return 1; 333 } 334 return 0; 335 } 336 337 /* Count how many GOT entries we may need */ 338 static unsigned int 339 count_gots (const Elf64_Rela *rela, unsigned int num) 340 { 341 unsigned int i, ret = 0; 342 343 /* Sure, this is order(n^2), but it's usually short, and not 344 time critical */ 345 for (i = 0; i < num; i++) { 346 switch (ELF64_R_TYPE(rela[i].r_info)) { 347 case R_IA64_LTOFF22: 348 case R_IA64_LTOFF22X: 349 case R_IA64_LTOFF64I: 350 case R_IA64_LTOFF_FPTR22: 351 case R_IA64_LTOFF_FPTR64I: 352 case R_IA64_LTOFF_FPTR32MSB: 353 case R_IA64_LTOFF_FPTR32LSB: 354 case R_IA64_LTOFF_FPTR64MSB: 355 case R_IA64_LTOFF_FPTR64LSB: 356 if (!duplicate_reloc(rela, i)) 357 ret++; 358 break; 359 } 360 } 361 return ret; 362 } 363 364 /* Count how many PLT entries we may need */ 365 static unsigned int 366 count_plts (const Elf64_Rela *rela, unsigned int num) 367 { 368 unsigned int i, ret = 0; 369 370 /* Sure, this is order(n^2), but it's usually short, and not 371 time critical */ 372 for (i = 0; i < num; i++) { 373 switch (ELF64_R_TYPE(rela[i].r_info)) { 374 case R_IA64_PCREL21B: 375 case R_IA64_PLTOFF22: 376 case R_IA64_PLTOFF64I: 377 case R_IA64_PLTOFF64MSB: 378 case R_IA64_PLTOFF64LSB: 379 case R_IA64_IPLTMSB: 380 case R_IA64_IPLTLSB: 381 if (!duplicate_reloc(rela, i)) 382 ret++; 383 break; 384 } 385 } 386 return ret; 387 } 388 389 /* We need to create an function-descriptors for any internal function 390 which is referenced. */ 391 static unsigned int 392 count_fdescs (const Elf64_Rela *rela, unsigned int num) 393 { 394 unsigned int i, ret = 0; 395 396 /* Sure, this is order(n^2), but it's usually short, and not time critical. */ 397 for (i = 0; i < num; i++) { 398 switch (ELF64_R_TYPE(rela[i].r_info)) { 399 case R_IA64_FPTR64I: 400 case R_IA64_FPTR32LSB: 401 case R_IA64_FPTR32MSB: 402 case R_IA64_FPTR64LSB: 403 case R_IA64_FPTR64MSB: 404 case R_IA64_LTOFF_FPTR22: 405 case R_IA64_LTOFF_FPTR32LSB: 406 case R_IA64_LTOFF_FPTR32MSB: 407 case R_IA64_LTOFF_FPTR64I: 408 case R_IA64_LTOFF_FPTR64LSB: 409 case R_IA64_LTOFF_FPTR64MSB: 410 case R_IA64_IPLTMSB: 411 case R_IA64_IPLTLSB: 412 /* 413 * Jumps to static functions sometimes go straight to their 414 * offset. Of course, that may not be possible if the jump is 415 * from init -> core or vice. versa, so we need to generate an 416 * FDESC (and PLT etc) for that. 417 */ 418 case R_IA64_PCREL21B: 419 if (!duplicate_reloc(rela, i)) 420 ret++; 421 break; 422 } 423 } 424 return ret; 425 } 426 427 int 428 module_frob_arch_sections (Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, char *secstrings, 429 struct module *mod) 430 { 431 unsigned long core_plts = 0, init_plts = 0, gots = 0, fdescs = 0; 432 Elf64_Shdr *s, *sechdrs_end = sechdrs + ehdr->e_shnum; 433 434 /* 435 * To store the PLTs and function-descriptors, we expand the .text section for 436 * core module-code and the .init.text section for initialization code. 437 */ 438 for (s = sechdrs; s < sechdrs_end; ++s) 439 if (strcmp(".core.plt", secstrings + s->sh_name) == 0) 440 mod->arch.core_plt = s; 441 else if (strcmp(".init.plt", secstrings + s->sh_name) == 0) 442 mod->arch.init_plt = s; 443 else if (strcmp(".got", secstrings + s->sh_name) == 0) 444 mod->arch.got = s; 445 else if (strcmp(".opd", secstrings + s->sh_name) == 0) 446 mod->arch.opd = s; 447 else if (strcmp(".IA_64.unwind", secstrings + s->sh_name) == 0) 448 mod->arch.unwind = s; 449 450 if (!mod->arch.core_plt || !mod->arch.init_plt || !mod->arch.got || !mod->arch.opd) { 451 printk(KERN_ERR "%s: sections missing\n", mod->name); 452 return -ENOEXEC; 453 } 454 455 /* GOT and PLTs can occur in any relocated section... */ 456 for (s = sechdrs + 1; s < sechdrs_end; ++s) { 457 const Elf64_Rela *rels = (void *)ehdr + s->sh_offset; 458 unsigned long numrels = s->sh_size/sizeof(Elf64_Rela); 459 460 if (s->sh_type != SHT_RELA) 461 continue; 462 463 gots += count_gots(rels, numrels); 464 fdescs += count_fdescs(rels, numrels); 465 if (strstr(secstrings + s->sh_name, ".init")) 466 init_plts += count_plts(rels, numrels); 467 else 468 core_plts += count_plts(rels, numrels); 469 } 470 471 mod->arch.core_plt->sh_type = SHT_NOBITS; 472 mod->arch.core_plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC; 473 mod->arch.core_plt->sh_addralign = 16; 474 mod->arch.core_plt->sh_size = core_plts * sizeof(struct plt_entry); 475 mod->arch.init_plt->sh_type = SHT_NOBITS; 476 mod->arch.init_plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC; 477 mod->arch.init_plt->sh_addralign = 16; 478 mod->arch.init_plt->sh_size = init_plts * sizeof(struct plt_entry); 479 mod->arch.got->sh_type = SHT_NOBITS; 480 mod->arch.got->sh_flags = ARCH_SHF_SMALL | SHF_ALLOC; 481 mod->arch.got->sh_addralign = 8; 482 mod->arch.got->sh_size = gots * sizeof(struct got_entry); 483 mod->arch.opd->sh_type = SHT_NOBITS; 484 mod->arch.opd->sh_flags = SHF_ALLOC; 485 mod->arch.opd->sh_addralign = 8; 486 mod->arch.opd->sh_size = fdescs * sizeof(struct fdesc); 487 DEBUGP("%s: core.plt=%lx, init.plt=%lx, got=%lx, fdesc=%lx\n", 488 __func__, mod->arch.core_plt->sh_size, mod->arch.init_plt->sh_size, 489 mod->arch.got->sh_size, mod->arch.opd->sh_size); 490 return 0; 491 } 492 493 static inline int 494 in_init (const struct module *mod, uint64_t addr) 495 { 496 return addr - (uint64_t) mod->module_init < mod->init_size; 497 } 498 499 static inline int 500 in_core (const struct module *mod, uint64_t addr) 501 { 502 return addr - (uint64_t) mod->module_core < mod->core_size; 503 } 504 505 static inline int 506 is_internal (const struct module *mod, uint64_t value) 507 { 508 return in_init(mod, value) || in_core(mod, value); 509 } 510 511 /* 512 * Get gp-relative offset for the linkage-table entry of VALUE. 513 */ 514 static uint64_t 515 get_ltoff (struct module *mod, uint64_t value, int *okp) 516 { 517 struct got_entry *got, *e; 518 519 if (!*okp) 520 return 0; 521 522 got = (void *) mod->arch.got->sh_addr; 523 for (e = got; e < got + mod->arch.next_got_entry; ++e) 524 if (e->val == value) 525 goto found; 526 527 /* Not enough GOT entries? */ 528 if (e >= (struct got_entry *) (mod->arch.got->sh_addr + mod->arch.got->sh_size)) 529 BUG(); 530 531 e->val = value; 532 ++mod->arch.next_got_entry; 533 found: 534 return (uint64_t) e - mod->arch.gp; 535 } 536 537 static inline int 538 gp_addressable (struct module *mod, uint64_t value) 539 { 540 return value - mod->arch.gp + MAX_LTOFF/2 < MAX_LTOFF; 541 } 542 543 /* Get PC-relative PLT entry for this value. Returns 0 on failure. */ 544 static uint64_t 545 get_plt (struct module *mod, const struct insn *insn, uint64_t value, int *okp) 546 { 547 struct plt_entry *plt, *plt_end; 548 uint64_t target_ip, target_gp; 549 550 if (!*okp) 551 return 0; 552 553 if (in_init(mod, (uint64_t) insn)) { 554 plt = (void *) mod->arch.init_plt->sh_addr; 555 plt_end = (void *) plt + mod->arch.init_plt->sh_size; 556 } else { 557 plt = (void *) mod->arch.core_plt->sh_addr; 558 plt_end = (void *) plt + mod->arch.core_plt->sh_size; 559 } 560 561 /* "value" is a pointer to a function-descriptor; fetch the target ip/gp from it: */ 562 target_ip = ((uint64_t *) value)[0]; 563 target_gp = ((uint64_t *) value)[1]; 564 565 /* Look for existing PLT entry. */ 566 while (plt->bundle[0][0]) { 567 if (plt_target(plt) == target_ip) 568 goto found; 569 if (++plt >= plt_end) 570 BUG(); 571 } 572 *plt = ia64_plt_template; 573 if (!patch_plt(mod, plt, target_ip, target_gp)) { 574 *okp = 0; 575 return 0; 576 } 577 #if ARCH_MODULE_DEBUG 578 if (plt_target(plt) != target_ip) { 579 printk("%s: mistargeted PLT: wanted %lx, got %lx\n", 580 __func__, target_ip, plt_target(plt)); 581 *okp = 0; 582 return 0; 583 } 584 #endif 585 found: 586 return (uint64_t) plt; 587 } 588 589 /* Get function descriptor for VALUE. */ 590 static uint64_t 591 get_fdesc (struct module *mod, uint64_t value, int *okp) 592 { 593 struct fdesc *fdesc = (void *) mod->arch.opd->sh_addr; 594 595 if (!*okp) 596 return 0; 597 598 if (!value) { 599 printk(KERN_ERR "%s: fdesc for zero requested!\n", mod->name); 600 return 0; 601 } 602 603 if (!is_internal(mod, value)) 604 /* 605 * If it's not a module-local entry-point, "value" already points to a 606 * function-descriptor. 607 */ 608 return value; 609 610 /* Look for existing function descriptor. */ 611 while (fdesc->ip) { 612 if (fdesc->ip == value) 613 return (uint64_t)fdesc; 614 if ((uint64_t) ++fdesc >= mod->arch.opd->sh_addr + mod->arch.opd->sh_size) 615 BUG(); 616 } 617 618 /* Create new one */ 619 fdesc->ip = value; 620 fdesc->gp = mod->arch.gp; 621 return (uint64_t) fdesc; 622 } 623 624 static inline int 625 do_reloc (struct module *mod, uint8_t r_type, Elf64_Sym *sym, uint64_t addend, 626 Elf64_Shdr *sec, void *location) 627 { 628 enum reloc_target_format format = (r_type >> FORMAT_SHIFT) & FORMAT_MASK; 629 enum reloc_value_formula formula = (r_type >> VALUE_SHIFT) & VALUE_MASK; 630 uint64_t val; 631 int ok = 1; 632 633 val = sym->st_value + addend; 634 635 switch (formula) { 636 case RV_SEGREL: /* segment base is arbitrarily chosen to be 0 for kernel modules */ 637 case RV_DIRECT: 638 break; 639 640 case RV_GPREL: val -= mod->arch.gp; break; 641 case RV_LTREL: val = get_ltoff(mod, val, &ok); break; 642 case RV_PLTREL: val = get_plt(mod, location, val, &ok); break; 643 case RV_FPTR: val = get_fdesc(mod, val, &ok); break; 644 case RV_SECREL: val -= sec->sh_addr; break; 645 case RV_LTREL_FPTR: val = get_ltoff(mod, get_fdesc(mod, val, &ok), &ok); break; 646 647 case RV_PCREL: 648 switch (r_type) { 649 case R_IA64_PCREL21B: 650 if ((in_init(mod, val) && in_core(mod, (uint64_t)location)) || 651 (in_core(mod, val) && in_init(mod, (uint64_t)location))) { 652 /* 653 * Init section may have been allocated far away from core, 654 * if the branch won't reach, then allocate a plt for it. 655 */ 656 uint64_t delta = ((int64_t)val - (int64_t)location) / 16; 657 if (delta + (1 << 20) >= (1 << 21)) { 658 val = get_fdesc(mod, val, &ok); 659 val = get_plt(mod, location, val, &ok); 660 } 661 } else if (!is_internal(mod, val)) 662 val = get_plt(mod, location, val, &ok); 663 /* FALL THROUGH */ 664 default: 665 val -= bundle(location); 666 break; 667 668 case R_IA64_PCREL32MSB: 669 case R_IA64_PCREL32LSB: 670 case R_IA64_PCREL64MSB: 671 case R_IA64_PCREL64LSB: 672 val -= (uint64_t) location; 673 break; 674 675 } 676 switch (r_type) { 677 case R_IA64_PCREL60B: format = RF_INSN60; break; 678 case R_IA64_PCREL21B: format = RF_INSN21B; break; 679 case R_IA64_PCREL21M: format = RF_INSN21M; break; 680 case R_IA64_PCREL21F: format = RF_INSN21F; break; 681 default: break; 682 } 683 break; 684 685 case RV_BDREL: 686 val -= (uint64_t) (in_init(mod, val) ? mod->module_init : mod->module_core); 687 break; 688 689 case RV_LTV: 690 /* can link-time value relocs happen here? */ 691 BUG(); 692 break; 693 694 case RV_PCREL2: 695 if (r_type == R_IA64_PCREL21BI) { 696 if (!is_internal(mod, val)) { 697 printk(KERN_ERR "%s: %s reloc against non-local symbol (%lx)\n", 698 __func__, reloc_name[r_type], val); 699 return -ENOEXEC; 700 } 701 format = RF_INSN21B; 702 } 703 val -= bundle(location); 704 break; 705 706 case RV_SPECIAL: 707 switch (r_type) { 708 case R_IA64_IPLTMSB: 709 case R_IA64_IPLTLSB: 710 val = get_fdesc(mod, get_plt(mod, location, val, &ok), &ok); 711 format = RF_64LSB; 712 if (r_type == R_IA64_IPLTMSB) 713 format = RF_64MSB; 714 break; 715 716 case R_IA64_SUB: 717 val = addend - sym->st_value; 718 format = RF_INSN64; 719 break; 720 721 case R_IA64_LTOFF22X: 722 if (gp_addressable(mod, val)) 723 val -= mod->arch.gp; 724 else 725 val = get_ltoff(mod, val, &ok); 726 format = RF_INSN22; 727 break; 728 729 case R_IA64_LDXMOV: 730 if (gp_addressable(mod, val)) { 731 /* turn "ld8" into "mov": */ 732 DEBUGP("%s: patching ld8 at %p to mov\n", __func__, location); 733 ia64_patch((u64) location, 0x1fff80fe000UL, 0x10000000000UL); 734 } 735 return 0; 736 737 default: 738 if (reloc_name[r_type]) 739 printk(KERN_ERR "%s: special reloc %s not supported", 740 mod->name, reloc_name[r_type]); 741 else 742 printk(KERN_ERR "%s: unknown special reloc %x\n", 743 mod->name, r_type); 744 return -ENOEXEC; 745 } 746 break; 747 748 case RV_TPREL: 749 case RV_LTREL_TPREL: 750 case RV_DTPMOD: 751 case RV_LTREL_DTPMOD: 752 case RV_DTPREL: 753 case RV_LTREL_DTPREL: 754 printk(KERN_ERR "%s: %s reloc not supported\n", 755 mod->name, reloc_name[r_type] ? reloc_name[r_type] : "?"); 756 return -ENOEXEC; 757 758 default: 759 printk(KERN_ERR "%s: unknown reloc %x\n", mod->name, r_type); 760 return -ENOEXEC; 761 } 762 763 if (!ok) 764 return -ENOEXEC; 765 766 DEBUGP("%s: [%p]<-%016lx = %s(%lx)\n", __func__, location, val, 767 reloc_name[r_type] ? reloc_name[r_type] : "?", sym->st_value + addend); 768 769 switch (format) { 770 case RF_INSN21B: ok = apply_imm21b(mod, location, (int64_t) val / 16); break; 771 case RF_INSN22: ok = apply_imm22(mod, location, val); break; 772 case RF_INSN64: ok = apply_imm64(mod, location, val); break; 773 case RF_INSN60: ok = apply_imm60(mod, location, (int64_t) val / 16); break; 774 case RF_32LSB: put_unaligned(val, (uint32_t *) location); break; 775 case RF_64LSB: put_unaligned(val, (uint64_t *) location); break; 776 case RF_32MSB: /* ia64 Linux is little-endian... */ 777 case RF_64MSB: /* ia64 Linux is little-endian... */ 778 case RF_INSN14: /* must be within-module, i.e., resolved by "ld -r" */ 779 case RF_INSN21M: /* must be within-module, i.e., resolved by "ld -r" */ 780 case RF_INSN21F: /* must be within-module, i.e., resolved by "ld -r" */ 781 printk(KERN_ERR "%s: format %u needed by %s reloc is not supported\n", 782 mod->name, format, reloc_name[r_type] ? reloc_name[r_type] : "?"); 783 return -ENOEXEC; 784 785 default: 786 printk(KERN_ERR "%s: relocation %s resulted in unknown format %u\n", 787 mod->name, reloc_name[r_type] ? reloc_name[r_type] : "?", format); 788 return -ENOEXEC; 789 } 790 return ok ? 0 : -ENOEXEC; 791 } 792 793 int 794 apply_relocate_add (Elf64_Shdr *sechdrs, const char *strtab, unsigned int symindex, 795 unsigned int relsec, struct module *mod) 796 { 797 unsigned int i, n = sechdrs[relsec].sh_size / sizeof(Elf64_Rela); 798 Elf64_Rela *rela = (void *) sechdrs[relsec].sh_addr; 799 Elf64_Shdr *target_sec; 800 int ret; 801 802 DEBUGP("%s: applying section %u (%u relocs) to %u\n", __func__, 803 relsec, n, sechdrs[relsec].sh_info); 804 805 target_sec = sechdrs + sechdrs[relsec].sh_info; 806 807 if (target_sec->sh_entsize == ~0UL) 808 /* 809 * If target section wasn't allocated, we don't need to relocate it. 810 * Happens, e.g., for debug sections. 811 */ 812 return 0; 813 814 if (!mod->arch.gp) { 815 /* 816 * XXX Should have an arch-hook for running this after final section 817 * addresses have been selected... 818 */ 819 uint64_t gp; 820 if (mod->core_size > MAX_LTOFF) 821 /* 822 * This takes advantage of fact that SHF_ARCH_SMALL gets allocated 823 * at the end of the module. 824 */ 825 gp = mod->core_size - MAX_LTOFF / 2; 826 else 827 gp = mod->core_size / 2; 828 gp = (uint64_t) mod->module_core + ((gp + 7) & -8); 829 mod->arch.gp = gp; 830 DEBUGP("%s: placing gp at 0x%lx\n", __func__, gp); 831 } 832 833 for (i = 0; i < n; i++) { 834 ret = do_reloc(mod, ELF64_R_TYPE(rela[i].r_info), 835 ((Elf64_Sym *) sechdrs[symindex].sh_addr 836 + ELF64_R_SYM(rela[i].r_info)), 837 rela[i].r_addend, target_sec, 838 (void *) target_sec->sh_addr + rela[i].r_offset); 839 if (ret < 0) 840 return ret; 841 } 842 return 0; 843 } 844 845 int 846 apply_relocate (Elf64_Shdr *sechdrs, const char *strtab, unsigned int symindex, 847 unsigned int relsec, struct module *mod) 848 { 849 printk(KERN_ERR "module %s: REL relocs in section %u unsupported\n", mod->name, relsec); 850 return -ENOEXEC; 851 } 852 853 /* 854 * Modules contain a single unwind table which covers both the core and the init text 855 * sections but since the two are not contiguous, we need to split this table up such that 856 * we can register (and unregister) each "segment" separately. Fortunately, this sounds 857 * more complicated than it really is. 858 */ 859 static void 860 register_unwind_table (struct module *mod) 861 { 862 struct unw_table_entry *start = (void *) mod->arch.unwind->sh_addr; 863 struct unw_table_entry *end = start + mod->arch.unwind->sh_size / sizeof (*start); 864 struct unw_table_entry tmp, *e1, *e2, *core, *init; 865 unsigned long num_init = 0, num_core = 0; 866 867 /* First, count how many init and core unwind-table entries there are. */ 868 for (e1 = start; e1 < end; ++e1) 869 if (in_init(mod, e1->start_offset)) 870 ++num_init; 871 else 872 ++num_core; 873 /* 874 * Second, sort the table such that all unwind-table entries for the init and core 875 * text sections are nicely separated. We do this with a stupid bubble sort 876 * (unwind tables don't get ridiculously huge). 877 */ 878 for (e1 = start; e1 < end; ++e1) { 879 for (e2 = e1 + 1; e2 < end; ++e2) { 880 if (e2->start_offset < e1->start_offset) { 881 tmp = *e1; 882 *e1 = *e2; 883 *e2 = tmp; 884 } 885 } 886 } 887 /* 888 * Third, locate the init and core segments in the unwind table: 889 */ 890 if (in_init(mod, start->start_offset)) { 891 init = start; 892 core = start + num_init; 893 } else { 894 core = start; 895 init = start + num_core; 896 } 897 898 DEBUGP("%s: name=%s, gp=%lx, num_init=%lu, num_core=%lu\n", __func__, 899 mod->name, mod->arch.gp, num_init, num_core); 900 901 /* 902 * Fourth, register both tables (if not empty). 903 */ 904 if (num_core > 0) { 905 mod->arch.core_unw_table = unw_add_unwind_table(mod->name, 0, mod->arch.gp, 906 core, core + num_core); 907 DEBUGP("%s: core: handle=%p [%p-%p)\n", __func__, 908 mod->arch.core_unw_table, core, core + num_core); 909 } 910 if (num_init > 0) { 911 mod->arch.init_unw_table = unw_add_unwind_table(mod->name, 0, mod->arch.gp, 912 init, init + num_init); 913 DEBUGP("%s: init: handle=%p [%p-%p)\n", __func__, 914 mod->arch.init_unw_table, init, init + num_init); 915 } 916 } 917 918 int 919 module_finalize (const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *mod) 920 { 921 DEBUGP("%s: init: entry=%p\n", __func__, mod->init); 922 if (mod->arch.unwind) 923 register_unwind_table(mod); 924 return 0; 925 } 926 927 void 928 module_arch_cleanup (struct module *mod) 929 { 930 if (mod->arch.init_unw_table) 931 unw_remove_unwind_table(mod->arch.init_unw_table); 932 if (mod->arch.core_unw_table) 933 unw_remove_unwind_table(mod->arch.core_unw_table); 934 } 935