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", 175 mod->name, (long) val); 176 return 0; 177 } 178 ia64_patch_imm60((u64) insn, val); 179 return 1; 180 } 181 182 static int 183 apply_imm22 (struct module *mod, struct insn *insn, uint64_t val) 184 { 185 if (val + (1 << 21) >= (1 << 22)) { 186 printk(KERN_ERR "%s: value %li out of IMM22 range\n", 187 mod->name, (long)val); 188 return 0; 189 } 190 ia64_patch((u64) insn, 0x01fffcfe000UL, ( ((val & 0x200000UL) << 15) /* bit 21 -> 36 */ 191 | ((val & 0x1f0000UL) << 6) /* bit 16 -> 22 */ 192 | ((val & 0x00ff80UL) << 20) /* bit 7 -> 27 */ 193 | ((val & 0x00007fUL) << 13) /* bit 0 -> 13 */)); 194 return 1; 195 } 196 197 static int 198 apply_imm21b (struct module *mod, struct insn *insn, uint64_t val) 199 { 200 if (val + (1 << 20) >= (1 << 21)) { 201 printk(KERN_ERR "%s: value %li out of IMM21b range\n", 202 mod->name, (long)val); 203 return 0; 204 } 205 ia64_patch((u64) insn, 0x11ffffe000UL, ( ((val & 0x100000UL) << 16) /* bit 20 -> 36 */ 206 | ((val & 0x0fffffUL) << 13) /* bit 0 -> 13 */)); 207 return 1; 208 } 209 210 #if USE_BRL 211 212 struct plt_entry { 213 /* Three instruction bundles in PLT. */ 214 unsigned char bundle[2][16]; 215 }; 216 217 static const struct plt_entry ia64_plt_template = { 218 { 219 { 220 0x04, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */ 221 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, /* movl gp=TARGET_GP */ 222 0x00, 0x00, 0x00, 0x60 223 }, 224 { 225 0x05, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */ 226 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* brl.many gp=TARGET_GP */ 227 0x08, 0x00, 0x00, 0xc0 228 } 229 } 230 }; 231 232 static int 233 patch_plt (struct module *mod, struct plt_entry *plt, long target_ip, unsigned long target_gp) 234 { 235 if (apply_imm64(mod, (struct insn *) (plt->bundle[0] + 2), target_gp) 236 && apply_imm60(mod, (struct insn *) (plt->bundle[1] + 2), 237 (target_ip - (int64_t) plt->bundle[1]) / 16)) 238 return 1; 239 return 0; 240 } 241 242 unsigned long 243 plt_target (struct plt_entry *plt) 244 { 245 uint64_t b0, b1, *b = (uint64_t *) plt->bundle[1]; 246 long off; 247 248 b0 = b[0]; b1 = b[1]; 249 off = ( ((b1 & 0x00fffff000000000UL) >> 36) /* imm20b -> bit 0 */ 250 | ((b0 >> 48) << 20) | ((b1 & 0x7fffffUL) << 36) /* imm39 -> bit 20 */ 251 | ((b1 & 0x0800000000000000UL) << 0)); /* i -> bit 59 */ 252 return (long) plt->bundle[1] + 16*off; 253 } 254 255 #else /* !USE_BRL */ 256 257 struct plt_entry { 258 /* Three instruction bundles in PLT. */ 259 unsigned char bundle[3][16]; 260 }; 261 262 static const struct plt_entry ia64_plt_template = { 263 { 264 { 265 0x05, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */ 266 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* movl r16=TARGET_IP */ 267 0x02, 0x00, 0x00, 0x60 268 }, 269 { 270 0x04, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MLX] nop.m 0 */ 271 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, /* movl gp=TARGET_GP */ 272 0x00, 0x00, 0x00, 0x60 273 }, 274 { 275 0x11, 0x00, 0x00, 0x00, 0x01, 0x00, /* [MIB] nop.m 0 */ 276 0x60, 0x80, 0x04, 0x80, 0x03, 0x00, /* mov b6=r16 */ 277 0x60, 0x00, 0x80, 0x00 /* br.few b6 */ 278 } 279 } 280 }; 281 282 static int 283 patch_plt (struct module *mod, struct plt_entry *plt, long target_ip, unsigned long target_gp) 284 { 285 if (apply_imm64(mod, (struct insn *) (plt->bundle[0] + 2), target_ip) 286 && apply_imm64(mod, (struct insn *) (plt->bundle[1] + 2), target_gp)) 287 return 1; 288 return 0; 289 } 290 291 unsigned long 292 plt_target (struct plt_entry *plt) 293 { 294 uint64_t b0, b1, *b = (uint64_t *) plt->bundle[0]; 295 296 b0 = b[0]; b1 = b[1]; 297 return ( ((b1 & 0x000007f000000000) >> 36) /* imm7b -> bit 0 */ 298 | ((b1 & 0x07fc000000000000) >> 43) /* imm9d -> bit 7 */ 299 | ((b1 & 0x0003e00000000000) >> 29) /* imm5c -> bit 16 */ 300 | ((b1 & 0x0000100000000000) >> 23) /* ic -> bit 21 */ 301 | ((b0 >> 46) << 22) | ((b1 & 0x7fffff) << 40) /* imm41 -> bit 22 */ 302 | ((b1 & 0x0800000000000000) << 4)); /* i -> bit 63 */ 303 } 304 305 #endif /* !USE_BRL */ 306 307 void 308 module_arch_freeing_init (struct module *mod) 309 { 310 if (mod->arch.init_unw_table) { 311 unw_remove_unwind_table(mod->arch.init_unw_table); 312 mod->arch.init_unw_table = NULL; 313 } 314 } 315 316 /* Have we already seen one of these relocations? */ 317 /* FIXME: we could look in other sections, too --RR */ 318 static int 319 duplicate_reloc (const Elf64_Rela *rela, unsigned int num) 320 { 321 unsigned int i; 322 323 for (i = 0; i < num; i++) { 324 if (rela[i].r_info == rela[num].r_info && rela[i].r_addend == rela[num].r_addend) 325 return 1; 326 } 327 return 0; 328 } 329 330 /* Count how many GOT entries we may need */ 331 static unsigned int 332 count_gots (const Elf64_Rela *rela, unsigned int num) 333 { 334 unsigned int i, ret = 0; 335 336 /* Sure, this is order(n^2), but it's usually short, and not 337 time critical */ 338 for (i = 0; i < num; i++) { 339 switch (ELF64_R_TYPE(rela[i].r_info)) { 340 case R_IA64_LTOFF22: 341 case R_IA64_LTOFF22X: 342 case R_IA64_LTOFF64I: 343 case R_IA64_LTOFF_FPTR22: 344 case R_IA64_LTOFF_FPTR64I: 345 case R_IA64_LTOFF_FPTR32MSB: 346 case R_IA64_LTOFF_FPTR32LSB: 347 case R_IA64_LTOFF_FPTR64MSB: 348 case R_IA64_LTOFF_FPTR64LSB: 349 if (!duplicate_reloc(rela, i)) 350 ret++; 351 break; 352 } 353 } 354 return ret; 355 } 356 357 /* Count how many PLT entries we may need */ 358 static unsigned int 359 count_plts (const Elf64_Rela *rela, unsigned int num) 360 { 361 unsigned int i, ret = 0; 362 363 /* Sure, this is order(n^2), but it's usually short, and not 364 time critical */ 365 for (i = 0; i < num; i++) { 366 switch (ELF64_R_TYPE(rela[i].r_info)) { 367 case R_IA64_PCREL21B: 368 case R_IA64_PLTOFF22: 369 case R_IA64_PLTOFF64I: 370 case R_IA64_PLTOFF64MSB: 371 case R_IA64_PLTOFF64LSB: 372 case R_IA64_IPLTMSB: 373 case R_IA64_IPLTLSB: 374 if (!duplicate_reloc(rela, i)) 375 ret++; 376 break; 377 } 378 } 379 return ret; 380 } 381 382 /* We need to create an function-descriptors for any internal function 383 which is referenced. */ 384 static unsigned int 385 count_fdescs (const Elf64_Rela *rela, unsigned int num) 386 { 387 unsigned int i, ret = 0; 388 389 /* Sure, this is order(n^2), but it's usually short, and not time critical. */ 390 for (i = 0; i < num; i++) { 391 switch (ELF64_R_TYPE(rela[i].r_info)) { 392 case R_IA64_FPTR64I: 393 case R_IA64_FPTR32LSB: 394 case R_IA64_FPTR32MSB: 395 case R_IA64_FPTR64LSB: 396 case R_IA64_FPTR64MSB: 397 case R_IA64_LTOFF_FPTR22: 398 case R_IA64_LTOFF_FPTR32LSB: 399 case R_IA64_LTOFF_FPTR32MSB: 400 case R_IA64_LTOFF_FPTR64I: 401 case R_IA64_LTOFF_FPTR64LSB: 402 case R_IA64_LTOFF_FPTR64MSB: 403 case R_IA64_IPLTMSB: 404 case R_IA64_IPLTLSB: 405 /* 406 * Jumps to static functions sometimes go straight to their 407 * offset. Of course, that may not be possible if the jump is 408 * from init -> core or vice. versa, so we need to generate an 409 * FDESC (and PLT etc) for that. 410 */ 411 case R_IA64_PCREL21B: 412 if (!duplicate_reloc(rela, i)) 413 ret++; 414 break; 415 } 416 } 417 return ret; 418 } 419 420 int 421 module_frob_arch_sections (Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, char *secstrings, 422 struct module *mod) 423 { 424 unsigned long core_plts = 0, init_plts = 0, gots = 0, fdescs = 0; 425 Elf64_Shdr *s, *sechdrs_end = sechdrs + ehdr->e_shnum; 426 427 /* 428 * To store the PLTs and function-descriptors, we expand the .text section for 429 * core module-code and the .init.text section for initialization code. 430 */ 431 for (s = sechdrs; s < sechdrs_end; ++s) 432 if (strcmp(".core.plt", secstrings + s->sh_name) == 0) 433 mod->arch.core_plt = s; 434 else if (strcmp(".init.plt", secstrings + s->sh_name) == 0) 435 mod->arch.init_plt = s; 436 else if (strcmp(".got", secstrings + s->sh_name) == 0) 437 mod->arch.got = s; 438 else if (strcmp(".opd", secstrings + s->sh_name) == 0) 439 mod->arch.opd = s; 440 else if (strcmp(".IA_64.unwind", secstrings + s->sh_name) == 0) 441 mod->arch.unwind = s; 442 #ifdef CONFIG_PARAVIRT 443 else if (strcmp(".paravirt_bundles", 444 secstrings + s->sh_name) == 0) 445 mod->arch.paravirt_bundles = s; 446 else if (strcmp(".paravirt_insts", 447 secstrings + s->sh_name) == 0) 448 mod->arch.paravirt_insts = s; 449 #endif 450 451 if (!mod->arch.core_plt || !mod->arch.init_plt || !mod->arch.got || !mod->arch.opd) { 452 printk(KERN_ERR "%s: sections missing\n", mod->name); 453 return -ENOEXEC; 454 } 455 456 /* GOT and PLTs can occur in any relocated section... */ 457 for (s = sechdrs + 1; s < sechdrs_end; ++s) { 458 const Elf64_Rela *rels = (void *)ehdr + s->sh_offset; 459 unsigned long numrels = s->sh_size/sizeof(Elf64_Rela); 460 461 if (s->sh_type != SHT_RELA) 462 continue; 463 464 gots += count_gots(rels, numrels); 465 fdescs += count_fdescs(rels, numrels); 466 if (strstr(secstrings + s->sh_name, ".init")) 467 init_plts += count_plts(rels, numrels); 468 else 469 core_plts += count_plts(rels, numrels); 470 } 471 472 mod->arch.core_plt->sh_type = SHT_NOBITS; 473 mod->arch.core_plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC; 474 mod->arch.core_plt->sh_addralign = 16; 475 mod->arch.core_plt->sh_size = core_plts * sizeof(struct plt_entry); 476 mod->arch.init_plt->sh_type = SHT_NOBITS; 477 mod->arch.init_plt->sh_flags = SHF_EXECINSTR | SHF_ALLOC; 478 mod->arch.init_plt->sh_addralign = 16; 479 mod->arch.init_plt->sh_size = init_plts * sizeof(struct plt_entry); 480 mod->arch.got->sh_type = SHT_NOBITS; 481 mod->arch.got->sh_flags = ARCH_SHF_SMALL | SHF_ALLOC; 482 mod->arch.got->sh_addralign = 8; 483 mod->arch.got->sh_size = gots * sizeof(struct got_entry); 484 mod->arch.opd->sh_type = SHT_NOBITS; 485 mod->arch.opd->sh_flags = SHF_ALLOC; 486 mod->arch.opd->sh_addralign = 8; 487 mod->arch.opd->sh_size = fdescs * sizeof(struct fdesc); 488 DEBUGP("%s: core.plt=%lx, init.plt=%lx, got=%lx, fdesc=%lx\n", 489 __func__, mod->arch.core_plt->sh_size, mod->arch.init_plt->sh_size, 490 mod->arch.got->sh_size, mod->arch.opd->sh_size); 491 return 0; 492 } 493 494 static inline int 495 in_init (const struct module *mod, uint64_t addr) 496 { 497 return addr - (uint64_t) mod->module_init < mod->init_size; 498 } 499 500 static inline int 501 in_core (const struct module *mod, uint64_t addr) 502 { 503 return addr - (uint64_t) mod->module_core < mod->core_size; 504 } 505 506 static inline int 507 is_internal (const struct module *mod, uint64_t value) 508 { 509 return in_init(mod, value) || in_core(mod, value); 510 } 511 512 /* 513 * Get gp-relative offset for the linkage-table entry of VALUE. 514 */ 515 static uint64_t 516 get_ltoff (struct module *mod, uint64_t value, int *okp) 517 { 518 struct got_entry *got, *e; 519 520 if (!*okp) 521 return 0; 522 523 got = (void *) mod->arch.got->sh_addr; 524 for (e = got; e < got + mod->arch.next_got_entry; ++e) 525 if (e->val == value) 526 goto found; 527 528 /* Not enough GOT entries? */ 529 BUG_ON(e >= (struct got_entry *) (mod->arch.got->sh_addr + mod->arch.got->sh_size)); 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 " 698 "non-local symbol (%lx)\n", __func__, 699 reloc_name[r_type], (unsigned long)val); 700 return -ENOEXEC; 701 } 702 format = RF_INSN21B; 703 } 704 val -= bundle(location); 705 break; 706 707 case RV_SPECIAL: 708 switch (r_type) { 709 case R_IA64_IPLTMSB: 710 case R_IA64_IPLTLSB: 711 val = get_fdesc(mod, get_plt(mod, location, val, &ok), &ok); 712 format = RF_64LSB; 713 if (r_type == R_IA64_IPLTMSB) 714 format = RF_64MSB; 715 break; 716 717 case R_IA64_SUB: 718 val = addend - sym->st_value; 719 format = RF_INSN64; 720 break; 721 722 case R_IA64_LTOFF22X: 723 if (gp_addressable(mod, val)) 724 val -= mod->arch.gp; 725 else 726 val = get_ltoff(mod, val, &ok); 727 format = RF_INSN22; 728 break; 729 730 case R_IA64_LDXMOV: 731 if (gp_addressable(mod, val)) { 732 /* turn "ld8" into "mov": */ 733 DEBUGP("%s: patching ld8 at %p to mov\n", __func__, location); 734 ia64_patch((u64) location, 0x1fff80fe000UL, 0x10000000000UL); 735 } 736 return 0; 737 738 default: 739 if (reloc_name[r_type]) 740 printk(KERN_ERR "%s: special reloc %s not supported", 741 mod->name, reloc_name[r_type]); 742 else 743 printk(KERN_ERR "%s: unknown special reloc %x\n", 744 mod->name, r_type); 745 return -ENOEXEC; 746 } 747 break; 748 749 case RV_TPREL: 750 case RV_LTREL_TPREL: 751 case RV_DTPMOD: 752 case RV_LTREL_DTPMOD: 753 case RV_DTPREL: 754 case RV_LTREL_DTPREL: 755 printk(KERN_ERR "%s: %s reloc not supported\n", 756 mod->name, reloc_name[r_type] ? reloc_name[r_type] : "?"); 757 return -ENOEXEC; 758 759 default: 760 printk(KERN_ERR "%s: unknown reloc %x\n", mod->name, r_type); 761 return -ENOEXEC; 762 } 763 764 if (!ok) 765 return -ENOEXEC; 766 767 DEBUGP("%s: [%p]<-%016lx = %s(%lx)\n", __func__, location, val, 768 reloc_name[r_type] ? reloc_name[r_type] : "?", sym->st_value + addend); 769 770 switch (format) { 771 case RF_INSN21B: ok = apply_imm21b(mod, location, (int64_t) val / 16); break; 772 case RF_INSN22: ok = apply_imm22(mod, location, val); break; 773 case RF_INSN64: ok = apply_imm64(mod, location, val); break; 774 case RF_INSN60: ok = apply_imm60(mod, location, (int64_t) val / 16); break; 775 case RF_32LSB: put_unaligned(val, (uint32_t *) location); break; 776 case RF_64LSB: put_unaligned(val, (uint64_t *) location); break; 777 case RF_32MSB: /* ia64 Linux is little-endian... */ 778 case RF_64MSB: /* ia64 Linux is little-endian... */ 779 case RF_INSN14: /* must be within-module, i.e., resolved by "ld -r" */ 780 case RF_INSN21M: /* must be within-module, i.e., resolved by "ld -r" */ 781 case RF_INSN21F: /* must be within-module, i.e., resolved by "ld -r" */ 782 printk(KERN_ERR "%s: format %u needed by %s reloc is not supported\n", 783 mod->name, format, reloc_name[r_type] ? reloc_name[r_type] : "?"); 784 return -ENOEXEC; 785 786 default: 787 printk(KERN_ERR "%s: relocation %s resulted in unknown format %u\n", 788 mod->name, reloc_name[r_type] ? reloc_name[r_type] : "?", format); 789 return -ENOEXEC; 790 } 791 return ok ? 0 : -ENOEXEC; 792 } 793 794 int 795 apply_relocate_add (Elf64_Shdr *sechdrs, const char *strtab, unsigned int symindex, 796 unsigned int relsec, struct module *mod) 797 { 798 unsigned int i, n = sechdrs[relsec].sh_size / sizeof(Elf64_Rela); 799 Elf64_Rela *rela = (void *) sechdrs[relsec].sh_addr; 800 Elf64_Shdr *target_sec; 801 int ret; 802 803 DEBUGP("%s: applying section %u (%u relocs) to %u\n", __func__, 804 relsec, n, sechdrs[relsec].sh_info); 805 806 target_sec = sechdrs + sechdrs[relsec].sh_info; 807 808 if (target_sec->sh_entsize == ~0UL) 809 /* 810 * If target section wasn't allocated, we don't need to relocate it. 811 * Happens, e.g., for debug sections. 812 */ 813 return 0; 814 815 if (!mod->arch.gp) { 816 /* 817 * XXX Should have an arch-hook for running this after final section 818 * addresses have been selected... 819 */ 820 uint64_t gp; 821 if (mod->core_size > MAX_LTOFF) 822 /* 823 * This takes advantage of fact that SHF_ARCH_SMALL gets allocated 824 * at the end of the module. 825 */ 826 gp = mod->core_size - MAX_LTOFF / 2; 827 else 828 gp = mod->core_size / 2; 829 gp = (uint64_t) mod->module_core + ((gp + 7) & -8); 830 mod->arch.gp = gp; 831 DEBUGP("%s: placing gp at 0x%lx\n", __func__, gp); 832 } 833 834 for (i = 0; i < n; i++) { 835 ret = do_reloc(mod, ELF64_R_TYPE(rela[i].r_info), 836 ((Elf64_Sym *) sechdrs[symindex].sh_addr 837 + ELF64_R_SYM(rela[i].r_info)), 838 rela[i].r_addend, target_sec, 839 (void *) target_sec->sh_addr + rela[i].r_offset); 840 if (ret < 0) 841 return ret; 842 } 843 return 0; 844 } 845 846 /* 847 * Modules contain a single unwind table which covers both the core and the init text 848 * sections but since the two are not contiguous, we need to split this table up such that 849 * we can register (and unregister) each "segment" separately. Fortunately, this sounds 850 * more complicated than it really is. 851 */ 852 static void 853 register_unwind_table (struct module *mod) 854 { 855 struct unw_table_entry *start = (void *) mod->arch.unwind->sh_addr; 856 struct unw_table_entry *end = start + mod->arch.unwind->sh_size / sizeof (*start); 857 struct unw_table_entry tmp, *e1, *e2, *core, *init; 858 unsigned long num_init = 0, num_core = 0; 859 860 /* First, count how many init and core unwind-table entries there are. */ 861 for (e1 = start; e1 < end; ++e1) 862 if (in_init(mod, e1->start_offset)) 863 ++num_init; 864 else 865 ++num_core; 866 /* 867 * Second, sort the table such that all unwind-table entries for the init and core 868 * text sections are nicely separated. We do this with a stupid bubble sort 869 * (unwind tables don't get ridiculously huge). 870 */ 871 for (e1 = start; e1 < end; ++e1) { 872 for (e2 = e1 + 1; e2 < end; ++e2) { 873 if (e2->start_offset < e1->start_offset) { 874 tmp = *e1; 875 *e1 = *e2; 876 *e2 = tmp; 877 } 878 } 879 } 880 /* 881 * Third, locate the init and core segments in the unwind table: 882 */ 883 if (in_init(mod, start->start_offset)) { 884 init = start; 885 core = start + num_init; 886 } else { 887 core = start; 888 init = start + num_core; 889 } 890 891 DEBUGP("%s: name=%s, gp=%lx, num_init=%lu, num_core=%lu\n", __func__, 892 mod->name, mod->arch.gp, num_init, num_core); 893 894 /* 895 * Fourth, register both tables (if not empty). 896 */ 897 if (num_core > 0) { 898 mod->arch.core_unw_table = unw_add_unwind_table(mod->name, 0, mod->arch.gp, 899 core, core + num_core); 900 DEBUGP("%s: core: handle=%p [%p-%p)\n", __func__, 901 mod->arch.core_unw_table, core, core + num_core); 902 } 903 if (num_init > 0) { 904 mod->arch.init_unw_table = unw_add_unwind_table(mod->name, 0, mod->arch.gp, 905 init, init + num_init); 906 DEBUGP("%s: init: handle=%p [%p-%p)\n", __func__, 907 mod->arch.init_unw_table, init, init + num_init); 908 } 909 } 910 911 int 912 module_finalize (const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *mod) 913 { 914 DEBUGP("%s: init: entry=%p\n", __func__, mod->init); 915 if (mod->arch.unwind) 916 register_unwind_table(mod); 917 #ifdef CONFIG_PARAVIRT 918 if (mod->arch.paravirt_bundles) { 919 struct paravirt_patch_site_bundle *start = 920 (struct paravirt_patch_site_bundle *) 921 mod->arch.paravirt_bundles->sh_addr; 922 struct paravirt_patch_site_bundle *end = 923 (struct paravirt_patch_site_bundle *) 924 (mod->arch.paravirt_bundles->sh_addr + 925 mod->arch.paravirt_bundles->sh_size); 926 927 paravirt_patch_apply_bundle(start, end); 928 } 929 if (mod->arch.paravirt_insts) { 930 struct paravirt_patch_site_inst *start = 931 (struct paravirt_patch_site_inst *) 932 mod->arch.paravirt_insts->sh_addr; 933 struct paravirt_patch_site_inst *end = 934 (struct paravirt_patch_site_inst *) 935 (mod->arch.paravirt_insts->sh_addr + 936 mod->arch.paravirt_insts->sh_size); 937 938 paravirt_patch_apply_inst(start, end); 939 } 940 #endif 941 return 0; 942 } 943 944 void 945 module_arch_cleanup (struct module *mod) 946 { 947 if (mod->arch.init_unw_table) 948 unw_remove_unwind_table(mod->arch.init_unw_table); 949 if (mod->arch.core_unw_table) 950 unw_remove_unwind_table(mod->arch.core_unw_table); 951 } 952