1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * x86 instruction analysis 4 * 5 * Copyright (C) IBM Corporation, 2002, 2004, 2009 6 */ 7 8 #include <linux/kernel.h> 9 #ifdef __KERNEL__ 10 #include <linux/string.h> 11 #else 12 #include <string.h> 13 #endif 14 #include "../include/asm/inat.h" /* __ignore_sync_check__ */ 15 #include "../include/asm/insn.h" /* __ignore_sync_check__ */ 16 #include "../include/asm-generic/unaligned.h" /* __ignore_sync_check__ */ 17 18 #include <linux/errno.h> 19 #include <linux/kconfig.h> 20 21 #include "../include/asm/emulate_prefix.h" /* __ignore_sync_check__ */ 22 23 #define leXX_to_cpu(t, r) \ 24 ({ \ 25 __typeof__(t) v; \ 26 switch (sizeof(t)) { \ 27 case 4: v = le32_to_cpu(r); break; \ 28 case 2: v = le16_to_cpu(r); break; \ 29 case 1: v = r; break; \ 30 default: \ 31 BUILD_BUG(); break; \ 32 } \ 33 v; \ 34 }) 35 36 /* Verify next sizeof(t) bytes can be on the same instruction */ 37 #define validate_next(t, insn, n) \ 38 ((insn)->next_byte + sizeof(t) + n <= (insn)->end_kaddr) 39 40 #define __get_next(t, insn) \ 41 ({ t r = get_unaligned((t *)(insn)->next_byte); (insn)->next_byte += sizeof(t); leXX_to_cpu(t, r); }) 42 43 #define __peek_nbyte_next(t, insn, n) \ 44 ({ t r = get_unaligned((t *)(insn)->next_byte + n); leXX_to_cpu(t, r); }) 45 46 #define get_next(t, insn) \ 47 ({ if (unlikely(!validate_next(t, insn, 0))) goto err_out; __get_next(t, insn); }) 48 49 #define peek_nbyte_next(t, insn, n) \ 50 ({ if (unlikely(!validate_next(t, insn, n))) goto err_out; __peek_nbyte_next(t, insn, n); }) 51 52 #define peek_next(t, insn) peek_nbyte_next(t, insn, 0) 53 54 /** 55 * insn_init() - initialize struct insn 56 * @insn: &struct insn to be initialized 57 * @kaddr: address (in kernel memory) of instruction (or copy thereof) 58 * @buf_len: length of the insn buffer at @kaddr 59 * @x86_64: !0 for 64-bit kernel or 64-bit app 60 */ 61 void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64) 62 { 63 /* 64 * Instructions longer than MAX_INSN_SIZE (15 bytes) are invalid 65 * even if the input buffer is long enough to hold them. 66 */ 67 if (buf_len > MAX_INSN_SIZE) 68 buf_len = MAX_INSN_SIZE; 69 70 memset(insn, 0, sizeof(*insn)); 71 insn->kaddr = kaddr; 72 insn->end_kaddr = kaddr + buf_len; 73 insn->next_byte = kaddr; 74 insn->x86_64 = x86_64; 75 insn->opnd_bytes = 4; 76 if (x86_64) 77 insn->addr_bytes = 8; 78 else 79 insn->addr_bytes = 4; 80 } 81 82 static const insn_byte_t xen_prefix[] = { __XEN_EMULATE_PREFIX }; 83 static const insn_byte_t kvm_prefix[] = { __KVM_EMULATE_PREFIX }; 84 85 static int __insn_get_emulate_prefix(struct insn *insn, 86 const insn_byte_t *prefix, size_t len) 87 { 88 size_t i; 89 90 for (i = 0; i < len; i++) { 91 if (peek_nbyte_next(insn_byte_t, insn, i) != prefix[i]) 92 goto err_out; 93 } 94 95 insn->emulate_prefix_size = len; 96 insn->next_byte += len; 97 98 return 1; 99 100 err_out: 101 return 0; 102 } 103 104 static void insn_get_emulate_prefix(struct insn *insn) 105 { 106 if (__insn_get_emulate_prefix(insn, xen_prefix, sizeof(xen_prefix))) 107 return; 108 109 __insn_get_emulate_prefix(insn, kvm_prefix, sizeof(kvm_prefix)); 110 } 111 112 /** 113 * insn_get_prefixes - scan x86 instruction prefix bytes 114 * @insn: &struct insn containing instruction 115 * 116 * Populates the @insn->prefixes bitmap, and updates @insn->next_byte 117 * to point to the (first) opcode. No effect if @insn->prefixes.got 118 * is already set. 119 * 120 * * Returns: 121 * 0: on success 122 * < 0: on error 123 */ 124 int insn_get_prefixes(struct insn *insn) 125 { 126 struct insn_field *prefixes = &insn->prefixes; 127 insn_attr_t attr; 128 insn_byte_t b, lb; 129 int i, nb; 130 131 if (prefixes->got) 132 return 0; 133 134 insn_get_emulate_prefix(insn); 135 136 nb = 0; 137 lb = 0; 138 b = peek_next(insn_byte_t, insn); 139 attr = inat_get_opcode_attribute(b); 140 while (inat_is_legacy_prefix(attr)) { 141 /* Skip if same prefix */ 142 for (i = 0; i < nb; i++) 143 if (prefixes->bytes[i] == b) 144 goto found; 145 if (nb == 4) 146 /* Invalid instruction */ 147 break; 148 prefixes->bytes[nb++] = b; 149 if (inat_is_address_size_prefix(attr)) { 150 /* address size switches 2/4 or 4/8 */ 151 if (insn->x86_64) 152 insn->addr_bytes ^= 12; 153 else 154 insn->addr_bytes ^= 6; 155 } else if (inat_is_operand_size_prefix(attr)) { 156 /* oprand size switches 2/4 */ 157 insn->opnd_bytes ^= 6; 158 } 159 found: 160 prefixes->nbytes++; 161 insn->next_byte++; 162 lb = b; 163 b = peek_next(insn_byte_t, insn); 164 attr = inat_get_opcode_attribute(b); 165 } 166 /* Set the last prefix */ 167 if (lb && lb != insn->prefixes.bytes[3]) { 168 if (unlikely(insn->prefixes.bytes[3])) { 169 /* Swap the last prefix */ 170 b = insn->prefixes.bytes[3]; 171 for (i = 0; i < nb; i++) 172 if (prefixes->bytes[i] == lb) 173 insn_set_byte(prefixes, i, b); 174 } 175 insn_set_byte(&insn->prefixes, 3, lb); 176 } 177 178 /* Decode REX prefix */ 179 if (insn->x86_64) { 180 b = peek_next(insn_byte_t, insn); 181 attr = inat_get_opcode_attribute(b); 182 if (inat_is_rex_prefix(attr)) { 183 insn_field_set(&insn->rex_prefix, b, 1); 184 insn->next_byte++; 185 if (X86_REX_W(b)) 186 /* REX.W overrides opnd_size */ 187 insn->opnd_bytes = 8; 188 } else if (inat_is_rex2_prefix(attr)) { 189 insn_set_byte(&insn->rex_prefix, 0, b); 190 b = peek_nbyte_next(insn_byte_t, insn, 1); 191 insn_set_byte(&insn->rex_prefix, 1, b); 192 insn->rex_prefix.nbytes = 2; 193 insn->next_byte += 2; 194 if (X86_REX_W(b)) 195 /* REX.W overrides opnd_size */ 196 insn->opnd_bytes = 8; 197 insn->rex_prefix.got = 1; 198 goto vex_end; 199 } 200 } 201 insn->rex_prefix.got = 1; 202 203 /* Decode VEX prefix */ 204 b = peek_next(insn_byte_t, insn); 205 attr = inat_get_opcode_attribute(b); 206 if (inat_is_vex_prefix(attr)) { 207 insn_byte_t b2 = peek_nbyte_next(insn_byte_t, insn, 1); 208 if (!insn->x86_64) { 209 /* 210 * In 32-bits mode, if the [7:6] bits (mod bits of 211 * ModRM) on the second byte are not 11b, it is 212 * LDS or LES or BOUND. 213 */ 214 if (X86_MODRM_MOD(b2) != 3) 215 goto vex_end; 216 } 217 insn_set_byte(&insn->vex_prefix, 0, b); 218 insn_set_byte(&insn->vex_prefix, 1, b2); 219 if (inat_is_evex_prefix(attr)) { 220 b2 = peek_nbyte_next(insn_byte_t, insn, 2); 221 insn_set_byte(&insn->vex_prefix, 2, b2); 222 b2 = peek_nbyte_next(insn_byte_t, insn, 3); 223 insn_set_byte(&insn->vex_prefix, 3, b2); 224 insn->vex_prefix.nbytes = 4; 225 insn->next_byte += 4; 226 if (insn->x86_64 && X86_VEX_W(b2)) 227 /* VEX.W overrides opnd_size */ 228 insn->opnd_bytes = 8; 229 } else if (inat_is_vex3_prefix(attr)) { 230 b2 = peek_nbyte_next(insn_byte_t, insn, 2); 231 insn_set_byte(&insn->vex_prefix, 2, b2); 232 insn->vex_prefix.nbytes = 3; 233 insn->next_byte += 3; 234 if (insn->x86_64 && X86_VEX_W(b2)) 235 /* VEX.W overrides opnd_size */ 236 insn->opnd_bytes = 8; 237 } else { 238 /* 239 * For VEX2, fake VEX3-like byte#2. 240 * Makes it easier to decode vex.W, vex.vvvv, 241 * vex.L and vex.pp. Masking with 0x7f sets vex.W == 0. 242 */ 243 insn_set_byte(&insn->vex_prefix, 2, b2 & 0x7f); 244 insn->vex_prefix.nbytes = 2; 245 insn->next_byte += 2; 246 } 247 } 248 vex_end: 249 insn->vex_prefix.got = 1; 250 251 prefixes->got = 1; 252 253 return 0; 254 255 err_out: 256 return -ENODATA; 257 } 258 259 /** 260 * insn_get_opcode - collect opcode(s) 261 * @insn: &struct insn containing instruction 262 * 263 * Populates @insn->opcode, updates @insn->next_byte to point past the 264 * opcode byte(s), and set @insn->attr (except for groups). 265 * If necessary, first collects any preceding (prefix) bytes. 266 * Sets @insn->opcode.value = opcode1. No effect if @insn->opcode.got 267 * is already 1. 268 * 269 * Returns: 270 * 0: on success 271 * < 0: on error 272 */ 273 int insn_get_opcode(struct insn *insn) 274 { 275 struct insn_field *opcode = &insn->opcode; 276 int pfx_id, ret; 277 insn_byte_t op; 278 279 if (opcode->got) 280 return 0; 281 282 ret = insn_get_prefixes(insn); 283 if (ret) 284 return ret; 285 286 /* Get first opcode */ 287 op = get_next(insn_byte_t, insn); 288 insn_set_byte(opcode, 0, op); 289 opcode->nbytes = 1; 290 291 /* Check if there is VEX prefix or not */ 292 if (insn_is_avx(insn)) { 293 insn_byte_t m, p; 294 m = insn_vex_m_bits(insn); 295 p = insn_vex_p_bits(insn); 296 insn->attr = inat_get_avx_attribute(op, m, p); 297 /* SCALABLE EVEX uses p bits to encode operand size */ 298 if (inat_evex_scalable(insn->attr) && !insn_vex_w_bit(insn) && 299 p == INAT_PFX_OPNDSZ) 300 insn->opnd_bytes = 2; 301 if ((inat_must_evex(insn->attr) && !insn_is_evex(insn)) || 302 (!inat_accept_vex(insn->attr) && 303 !inat_is_group(insn->attr))) { 304 /* This instruction is bad */ 305 insn->attr = 0; 306 return -EINVAL; 307 } 308 /* VEX has only 1 byte for opcode */ 309 goto end; 310 } 311 312 /* Check if there is REX2 prefix or not */ 313 if (insn_is_rex2(insn)) { 314 if (insn_rex2_m_bit(insn)) { 315 /* map 1 is escape 0x0f */ 316 insn_attr_t esc_attr = inat_get_opcode_attribute(0x0f); 317 318 pfx_id = insn_last_prefix_id(insn); 319 insn->attr = inat_get_escape_attribute(op, pfx_id, esc_attr); 320 } else { 321 insn->attr = inat_get_opcode_attribute(op); 322 } 323 goto end; 324 } 325 326 insn->attr = inat_get_opcode_attribute(op); 327 while (inat_is_escape(insn->attr)) { 328 /* Get escaped opcode */ 329 op = get_next(insn_byte_t, insn); 330 opcode->bytes[opcode->nbytes++] = op; 331 pfx_id = insn_last_prefix_id(insn); 332 insn->attr = inat_get_escape_attribute(op, pfx_id, insn->attr); 333 } 334 335 if (inat_must_vex(insn->attr)) { 336 /* This instruction is bad */ 337 insn->attr = 0; 338 return -EINVAL; 339 } 340 end: 341 opcode->got = 1; 342 return 0; 343 344 err_out: 345 return -ENODATA; 346 } 347 348 /** 349 * insn_get_modrm - collect ModRM byte, if any 350 * @insn: &struct insn containing instruction 351 * 352 * Populates @insn->modrm and updates @insn->next_byte to point past the 353 * ModRM byte, if any. If necessary, first collects the preceding bytes 354 * (prefixes and opcode(s)). No effect if @insn->modrm.got is already 1. 355 * 356 * Returns: 357 * 0: on success 358 * < 0: on error 359 */ 360 int insn_get_modrm(struct insn *insn) 361 { 362 struct insn_field *modrm = &insn->modrm; 363 insn_byte_t pfx_id, mod; 364 int ret; 365 366 if (modrm->got) 367 return 0; 368 369 ret = insn_get_opcode(insn); 370 if (ret) 371 return ret; 372 373 if (inat_has_modrm(insn->attr)) { 374 mod = get_next(insn_byte_t, insn); 375 insn_field_set(modrm, mod, 1); 376 if (inat_is_group(insn->attr)) { 377 pfx_id = insn_last_prefix_id(insn); 378 insn->attr = inat_get_group_attribute(mod, pfx_id, 379 insn->attr); 380 if (insn_is_avx(insn) && !inat_accept_vex(insn->attr)) { 381 /* Bad insn */ 382 insn->attr = 0; 383 return -EINVAL; 384 } 385 } 386 } 387 388 if (insn->x86_64 && inat_is_force64(insn->attr)) 389 insn->opnd_bytes = 8; 390 391 modrm->got = 1; 392 return 0; 393 394 err_out: 395 return -ENODATA; 396 } 397 398 399 /** 400 * insn_rip_relative() - Does instruction use RIP-relative addressing mode? 401 * @insn: &struct insn containing instruction 402 * 403 * If necessary, first collects the instruction up to and including the 404 * ModRM byte. No effect if @insn->x86_64 is 0. 405 */ 406 int insn_rip_relative(struct insn *insn) 407 { 408 struct insn_field *modrm = &insn->modrm; 409 int ret; 410 411 if (!insn->x86_64) 412 return 0; 413 414 ret = insn_get_modrm(insn); 415 if (ret) 416 return 0; 417 /* 418 * For rip-relative instructions, the mod field (top 2 bits) 419 * is zero and the r/m field (bottom 3 bits) is 0x5. 420 */ 421 return (modrm->nbytes && (modrm->bytes[0] & 0xc7) == 0x5); 422 } 423 424 /** 425 * insn_get_sib() - Get the SIB byte of instruction 426 * @insn: &struct insn containing instruction 427 * 428 * If necessary, first collects the instruction up to and including the 429 * ModRM byte. 430 * 431 * Returns: 432 * 0: if decoding succeeded 433 * < 0: otherwise. 434 */ 435 int insn_get_sib(struct insn *insn) 436 { 437 insn_byte_t modrm; 438 int ret; 439 440 if (insn->sib.got) 441 return 0; 442 443 ret = insn_get_modrm(insn); 444 if (ret) 445 return ret; 446 447 if (insn->modrm.nbytes) { 448 modrm = insn->modrm.bytes[0]; 449 if (insn->addr_bytes != 2 && 450 X86_MODRM_MOD(modrm) != 3 && X86_MODRM_RM(modrm) == 4) { 451 insn_field_set(&insn->sib, 452 get_next(insn_byte_t, insn), 1); 453 } 454 } 455 insn->sib.got = 1; 456 457 return 0; 458 459 err_out: 460 return -ENODATA; 461 } 462 463 464 /** 465 * insn_get_displacement() - Get the displacement of instruction 466 * @insn: &struct insn containing instruction 467 * 468 * If necessary, first collects the instruction up to and including the 469 * SIB byte. 470 * Displacement value is sign-expanded. 471 * 472 * * Returns: 473 * 0: if decoding succeeded 474 * < 0: otherwise. 475 */ 476 int insn_get_displacement(struct insn *insn) 477 { 478 insn_byte_t mod, rm, base; 479 int ret; 480 481 if (insn->displacement.got) 482 return 0; 483 484 ret = insn_get_sib(insn); 485 if (ret) 486 return ret; 487 488 if (insn->modrm.nbytes) { 489 /* 490 * Interpreting the modrm byte: 491 * mod = 00 - no displacement fields (exceptions below) 492 * mod = 01 - 1-byte displacement field 493 * mod = 10 - displacement field is 4 bytes, or 2 bytes if 494 * address size = 2 (0x67 prefix in 32-bit mode) 495 * mod = 11 - no memory operand 496 * 497 * If address size = 2... 498 * mod = 00, r/m = 110 - displacement field is 2 bytes 499 * 500 * If address size != 2... 501 * mod != 11, r/m = 100 - SIB byte exists 502 * mod = 00, SIB base = 101 - displacement field is 4 bytes 503 * mod = 00, r/m = 101 - rip-relative addressing, displacement 504 * field is 4 bytes 505 */ 506 mod = X86_MODRM_MOD(insn->modrm.value); 507 rm = X86_MODRM_RM(insn->modrm.value); 508 base = X86_SIB_BASE(insn->sib.value); 509 if (mod == 3) 510 goto out; 511 if (mod == 1) { 512 insn_field_set(&insn->displacement, 513 get_next(signed char, insn), 1); 514 } else if (insn->addr_bytes == 2) { 515 if ((mod == 0 && rm == 6) || mod == 2) { 516 insn_field_set(&insn->displacement, 517 get_next(short, insn), 2); 518 } 519 } else { 520 if ((mod == 0 && rm == 5) || mod == 2 || 521 (mod == 0 && base == 5)) { 522 insn_field_set(&insn->displacement, 523 get_next(int, insn), 4); 524 } 525 } 526 } 527 out: 528 insn->displacement.got = 1; 529 return 0; 530 531 err_out: 532 return -ENODATA; 533 } 534 535 /* Decode moffset16/32/64. Return 0 if failed */ 536 static int __get_moffset(struct insn *insn) 537 { 538 switch (insn->addr_bytes) { 539 case 2: 540 insn_field_set(&insn->moffset1, get_next(short, insn), 2); 541 break; 542 case 4: 543 insn_field_set(&insn->moffset1, get_next(int, insn), 4); 544 break; 545 case 8: 546 insn_field_set(&insn->moffset1, get_next(int, insn), 4); 547 insn_field_set(&insn->moffset2, get_next(int, insn), 4); 548 break; 549 default: /* opnd_bytes must be modified manually */ 550 goto err_out; 551 } 552 insn->moffset1.got = insn->moffset2.got = 1; 553 554 return 1; 555 556 err_out: 557 return 0; 558 } 559 560 /* Decode imm v32(Iz). Return 0 if failed */ 561 static int __get_immv32(struct insn *insn) 562 { 563 switch (insn->opnd_bytes) { 564 case 2: 565 insn_field_set(&insn->immediate, get_next(short, insn), 2); 566 break; 567 case 4: 568 case 8: 569 insn_field_set(&insn->immediate, get_next(int, insn), 4); 570 break; 571 default: /* opnd_bytes must be modified manually */ 572 goto err_out; 573 } 574 575 return 1; 576 577 err_out: 578 return 0; 579 } 580 581 /* Decode imm v64(Iv/Ov), Return 0 if failed */ 582 static int __get_immv(struct insn *insn) 583 { 584 switch (insn->opnd_bytes) { 585 case 2: 586 insn_field_set(&insn->immediate1, get_next(short, insn), 2); 587 break; 588 case 4: 589 insn_field_set(&insn->immediate1, get_next(int, insn), 4); 590 insn->immediate1.nbytes = 4; 591 break; 592 case 8: 593 insn_field_set(&insn->immediate1, get_next(int, insn), 4); 594 insn_field_set(&insn->immediate2, get_next(int, insn), 4); 595 break; 596 default: /* opnd_bytes must be modified manually */ 597 goto err_out; 598 } 599 insn->immediate1.got = insn->immediate2.got = 1; 600 601 return 1; 602 err_out: 603 return 0; 604 } 605 606 /* Decode ptr16:16/32(Ap) */ 607 static int __get_immptr(struct insn *insn) 608 { 609 switch (insn->opnd_bytes) { 610 case 2: 611 insn_field_set(&insn->immediate1, get_next(short, insn), 2); 612 break; 613 case 4: 614 insn_field_set(&insn->immediate1, get_next(int, insn), 4); 615 break; 616 case 8: 617 /* ptr16:64 is not exist (no segment) */ 618 return 0; 619 default: /* opnd_bytes must be modified manually */ 620 goto err_out; 621 } 622 insn_field_set(&insn->immediate2, get_next(unsigned short, insn), 2); 623 insn->immediate1.got = insn->immediate2.got = 1; 624 625 return 1; 626 err_out: 627 return 0; 628 } 629 630 /** 631 * insn_get_immediate() - Get the immediate in an instruction 632 * @insn: &struct insn containing instruction 633 * 634 * If necessary, first collects the instruction up to and including the 635 * displacement bytes. 636 * Basically, most of immediates are sign-expanded. Unsigned-value can be 637 * computed by bit masking with ((1 << (nbytes * 8)) - 1) 638 * 639 * Returns: 640 * 0: on success 641 * < 0: on error 642 */ 643 int insn_get_immediate(struct insn *insn) 644 { 645 int ret; 646 647 if (insn->immediate.got) 648 return 0; 649 650 ret = insn_get_displacement(insn); 651 if (ret) 652 return ret; 653 654 if (inat_has_moffset(insn->attr)) { 655 if (!__get_moffset(insn)) 656 goto err_out; 657 goto done; 658 } 659 660 if (!inat_has_immediate(insn->attr)) 661 /* no immediates */ 662 goto done; 663 664 switch (inat_immediate_size(insn->attr)) { 665 case INAT_IMM_BYTE: 666 insn_field_set(&insn->immediate, get_next(signed char, insn), 1); 667 break; 668 case INAT_IMM_WORD: 669 insn_field_set(&insn->immediate, get_next(short, insn), 2); 670 break; 671 case INAT_IMM_DWORD: 672 insn_field_set(&insn->immediate, get_next(int, insn), 4); 673 break; 674 case INAT_IMM_QWORD: 675 insn_field_set(&insn->immediate1, get_next(int, insn), 4); 676 insn_field_set(&insn->immediate2, get_next(int, insn), 4); 677 break; 678 case INAT_IMM_PTR: 679 if (!__get_immptr(insn)) 680 goto err_out; 681 break; 682 case INAT_IMM_VWORD32: 683 if (!__get_immv32(insn)) 684 goto err_out; 685 break; 686 case INAT_IMM_VWORD: 687 if (!__get_immv(insn)) 688 goto err_out; 689 break; 690 default: 691 /* Here, insn must have an immediate, but failed */ 692 goto err_out; 693 } 694 if (inat_has_second_immediate(insn->attr)) { 695 insn_field_set(&insn->immediate2, get_next(signed char, insn), 1); 696 } 697 done: 698 insn->immediate.got = 1; 699 return 0; 700 701 err_out: 702 return -ENODATA; 703 } 704 705 /** 706 * insn_get_length() - Get the length of instruction 707 * @insn: &struct insn containing instruction 708 * 709 * If necessary, first collects the instruction up to and including the 710 * immediates bytes. 711 * 712 * Returns: 713 * - 0 on success 714 * - < 0 on error 715 */ 716 int insn_get_length(struct insn *insn) 717 { 718 int ret; 719 720 if (insn->length) 721 return 0; 722 723 ret = insn_get_immediate(insn); 724 if (ret) 725 return ret; 726 727 insn->length = (unsigned char)((unsigned long)insn->next_byte 728 - (unsigned long)insn->kaddr); 729 730 return 0; 731 } 732 733 /* Ensure this instruction is decoded completely */ 734 static inline int insn_complete(struct insn *insn) 735 { 736 return insn->opcode.got && insn->modrm.got && insn->sib.got && 737 insn->displacement.got && insn->immediate.got; 738 } 739 740 /** 741 * insn_decode() - Decode an x86 instruction 742 * @insn: &struct insn to be initialized 743 * @kaddr: address (in kernel memory) of instruction (or copy thereof) 744 * @buf_len: length of the insn buffer at @kaddr 745 * @m: insn mode, see enum insn_mode 746 * 747 * Returns: 748 * 0: if decoding succeeded 749 * < 0: otherwise. 750 */ 751 int insn_decode(struct insn *insn, const void *kaddr, int buf_len, enum insn_mode m) 752 { 753 int ret; 754 755 #define INSN_MODE_KERN (enum insn_mode)-1 /* __ignore_sync_check__ mode is only valid in the kernel */ 756 757 if (m == INSN_MODE_KERN) 758 insn_init(insn, kaddr, buf_len, IS_ENABLED(CONFIG_X86_64)); 759 else 760 insn_init(insn, kaddr, buf_len, m == INSN_MODE_64); 761 762 ret = insn_get_length(insn); 763 if (ret) 764 return ret; 765 766 if (insn_complete(insn)) 767 return 0; 768 769 return -EINVAL; 770 } 771