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1/*
2 * x86 instruction analysis
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright (C) IBM Corporation, 2002, 2004, 2009
19 */
20
21#ifdef __KERNEL__
22#include <linux/string.h>
23#else
24#include <string.h>
25#endif
26#include <asm/inat.h>
27#include <asm/insn.h>
28
29/* Verify next sizeof(t) bytes can be on the same instruction */
30#define validate_next(t, insn, n) \
31 ((insn)->next_byte + sizeof(t) + n - (insn)->kaddr <= MAX_INSN_SIZE)
32
33#define __get_next(t, insn) \
34 ({ t r = *(t*)insn->next_byte; insn->next_byte += sizeof(t); r; })
35
36#define __peek_nbyte_next(t, insn, n) \
37 ({ t r = *(t*)((insn)->next_byte + n); r; })
38
39#define get_next(t, insn) \
40 ({ if (unlikely(!validate_next(t, insn, 0))) goto err_out; __get_next(t, insn); })
41
42#define peek_nbyte_next(t, insn, n) \
43 ({ if (unlikely(!validate_next(t, insn, n))) goto err_out; __peek_nbyte_next(t, insn, n); })
44
45#define peek_next(t, insn) peek_nbyte_next(t, insn, 0)
46
47/**
48 * insn_init() - initialize struct insn
49 * @insn: &struct insn to be initialized
50 * @kaddr: address (in kernel memory) of instruction (or copy thereof)
51 * @x86_64: !0 for 64-bit kernel or 64-bit app
52 */
53void insn_init(struct insn *insn, const void *kaddr, int x86_64)
54{
55 memset(insn, 0, sizeof(*insn));
56 insn->kaddr = kaddr;
57 insn->next_byte = kaddr;
58 insn->x86_64 = x86_64 ? 1 : 0;
59 insn->opnd_bytes = 4;
60 if (x86_64)
61 insn->addr_bytes = 8;
62 else
63 insn->addr_bytes = 4;
64}
65
66/**
67 * insn_get_prefixes - scan x86 instruction prefix bytes
68 * @insn: &struct insn containing instruction
69 *
70 * Populates the @insn->prefixes bitmap, and updates @insn->next_byte
71 * to point to the (first) opcode. No effect if @insn->prefixes.got
72 * is already set.
73 */
74void insn_get_prefixes(struct insn *insn)
75{
76 struct insn_field *prefixes = &insn->prefixes;
77 insn_attr_t attr;
78 insn_byte_t b, lb;
79 int i, nb;
80
81 if (prefixes->got)
82 return;
83
84 nb = 0;
85 lb = 0;
86 b = peek_next(insn_byte_t, insn);
87 attr = inat_get_opcode_attribute(b);
88 while (inat_is_legacy_prefix(attr)) {
89 /* Skip if same prefix */
90 for (i = 0; i < nb; i++)
91 if (prefixes->bytes[i] == b)
92 goto found;
93 if (nb == 4)
94 /* Invalid instruction */
95 break;
96 prefixes->bytes[nb++] = b;
97 if (inat_is_address_size_prefix(attr)) {
98 /* address size switches 2/4 or 4/8 */
99 if (insn->x86_64)
100 insn->addr_bytes ^= 12;
101 else
102 insn->addr_bytes ^= 6;
103 } else if (inat_is_operand_size_prefix(attr)) {
104 /* oprand size switches 2/4 */
105 insn->opnd_bytes ^= 6;
106 }
107found:
108 prefixes->nbytes++;
109 insn->next_byte++;
110 lb = b;
111 b = peek_next(insn_byte_t, insn);
112 attr = inat_get_opcode_attribute(b);
113 }
114 /* Set the last prefix */
115 if (lb && lb != insn->prefixes.bytes[3]) {
116 if (unlikely(insn->prefixes.bytes[3])) {
117 /* Swap the last prefix */
118 b = insn->prefixes.bytes[3];
119 for (i = 0; i < nb; i++)
120 if (prefixes->bytes[i] == lb)
121 prefixes->bytes[i] = b;
122 }
123 insn->prefixes.bytes[3] = lb;
124 }
125
126 /* Decode REX prefix */
127 if (insn->x86_64) {
128 b = peek_next(insn_byte_t, insn);
129 attr = inat_get_opcode_attribute(b);
130 if (inat_is_rex_prefix(attr)) {
131 insn->rex_prefix.value = b;
132 insn->rex_prefix.nbytes = 1;
133 insn->next_byte++;
134 if (X86_REX_W(b))
135 /* REX.W overrides opnd_size */
136 insn->opnd_bytes = 8;
137 }
138 }
139 insn->rex_prefix.got = 1;
140
141 /* Decode VEX prefix */
142 b = peek_next(insn_byte_t, insn);
143 attr = inat_get_opcode_attribute(b);
144 if (inat_is_vex_prefix(attr)) {
145 insn_byte_t b2 = peek_nbyte_next(insn_byte_t, insn, 1);
146 if (!insn->x86_64) {
147 /*
148 * In 32-bits mode, if the [7:6] bits (mod bits of
149 * ModRM) on the second byte are not 11b, it is
150 * LDS or LES.
151 */
152 if (X86_MODRM_MOD(b2) != 3)
153 goto vex_end;
154 }
155 insn->vex_prefix.bytes[0] = b;
156 insn->vex_prefix.bytes[1] = b2;
157 if (inat_is_vex3_prefix(attr)) {
158 b2 = peek_nbyte_next(insn_byte_t, insn, 2);
159 insn->vex_prefix.bytes[2] = b2;
160 insn->vex_prefix.nbytes = 3;
161 insn->next_byte += 3;
162 if (insn->x86_64 && X86_VEX_W(b2))
163 /* VEX.W overrides opnd_size */
164 insn->opnd_bytes = 8;
165 } else {
166 insn->vex_prefix.nbytes = 2;
167 insn->next_byte += 2;
168 }
169 }
170vex_end:
171 insn->vex_prefix.got = 1;
172
173 prefixes->got = 1;
174
175err_out:
176 return;
177}
178
179/**
180 * insn_get_opcode - collect opcode(s)
181 * @insn: &struct insn containing instruction
182 *
183 * Populates @insn->opcode, updates @insn->next_byte to point past the
184 * opcode byte(s), and set @insn->attr (except for groups).
185 * If necessary, first collects any preceding (prefix) bytes.
186 * Sets @insn->opcode.value = opcode1. No effect if @insn->opcode.got
187 * is already 1.
188 */
189void insn_get_opcode(struct insn *insn)
190{
191 struct insn_field *opcode = &insn->opcode;
192 insn_byte_t op;
193 int pfx_id;
194 if (opcode->got)
195 return;
196 if (!insn->prefixes.got)
197 insn_get_prefixes(insn);
198
199 /* Get first opcode */
200 op = get_next(insn_byte_t, insn);
201 opcode->bytes[0] = op;
202 opcode->nbytes = 1;
203
204 /* Check if there is VEX prefix or not */
205 if (insn_is_avx(insn)) {
206 insn_byte_t m, p;
207 m = insn_vex_m_bits(insn);
208 p = insn_vex_p_bits(insn);
209 insn->attr = inat_get_avx_attribute(op, m, p);
210 if (!inat_accept_vex(insn->attr) && !inat_is_group(insn->attr))
211 insn->attr = 0; /* This instruction is bad */
212 goto end; /* VEX has only 1 byte for opcode */
213 }
214
215 insn->attr = inat_get_opcode_attribute(op);
216 while (inat_is_escape(insn->attr)) {
217 /* Get escaped opcode */
218 op = get_next(insn_byte_t, insn);
219 opcode->bytes[opcode->nbytes++] = op;
220 pfx_id = insn_last_prefix_id(insn);
221 insn->attr = inat_get_escape_attribute(op, pfx_id, insn->attr);
222 }
223 if (inat_must_vex(insn->attr))
224 insn->attr = 0; /* This instruction is bad */
225end:
226 opcode->got = 1;
227
228err_out:
229 return;
230}
231
232/**
233 * insn_get_modrm - collect ModRM byte, if any
234 * @insn: &struct insn containing instruction
235 *
236 * Populates @insn->modrm and updates @insn->next_byte to point past the
237 * ModRM byte, if any. If necessary, first collects the preceding bytes
238 * (prefixes and opcode(s)). No effect if @insn->modrm.got is already 1.
239 */
240void insn_get_modrm(struct insn *insn)
241{
242 struct insn_field *modrm = &insn->modrm;
243 insn_byte_t pfx_id, mod;
244 if (modrm->got)
245 return;
246 if (!insn->opcode.got)
247 insn_get_opcode(insn);
248
249 if (inat_has_modrm(insn->attr)) {
250 mod = get_next(insn_byte_t, insn);
251 modrm->value = mod;
252 modrm->nbytes = 1;
253 if (inat_is_group(insn->attr)) {
254 pfx_id = insn_last_prefix_id(insn);
255 insn->attr = inat_get_group_attribute(mod, pfx_id,
256 insn->attr);
257 if (insn_is_avx(insn) && !inat_accept_vex(insn->attr))
258 insn->attr = 0; /* This is bad */
259 }
260 }
261
262 if (insn->x86_64 && inat_is_force64(insn->attr))
263 insn->opnd_bytes = 8;
264 modrm->got = 1;
265
266err_out:
267 return;
268}
269
270
271/**
272 * insn_rip_relative() - Does instruction use RIP-relative addressing mode?
273 * @insn: &struct insn containing instruction
274 *
275 * If necessary, first collects the instruction up to and including the
276 * ModRM byte. No effect if @insn->x86_64 is 0.
277 */
278int insn_rip_relative(struct insn *insn)
279{
280 struct insn_field *modrm = &insn->modrm;
281
282 if (!insn->x86_64)
283 return 0;
284 if (!modrm->got)
285 insn_get_modrm(insn);
286 /*
287 * For rip-relative instructions, the mod field (top 2 bits)
288 * is zero and the r/m field (bottom 3 bits) is 0x5.
289 */
290 return (modrm->nbytes && (modrm->value & 0xc7) == 0x5);
291}
292
293/**
294 * insn_get_sib() - Get the SIB byte of instruction
295 * @insn: &struct insn containing instruction
296 *
297 * If necessary, first collects the instruction up to and including the
298 * ModRM byte.
299 */
300void insn_get_sib(struct insn *insn)
301{
302 insn_byte_t modrm;
303
304 if (insn->sib.got)
305 return;
306 if (!insn->modrm.got)
307 insn_get_modrm(insn);
308 if (insn->modrm.nbytes) {
309 modrm = (insn_byte_t)insn->modrm.value;
310 if (insn->addr_bytes != 2 &&
311 X86_MODRM_MOD(modrm) != 3 && X86_MODRM_RM(modrm) == 4) {
312 insn->sib.value = get_next(insn_byte_t, insn);
313 insn->sib.nbytes = 1;
314 }
315 }
316 insn->sib.got = 1;
317
318err_out:
319 return;
320}
321
322
323/**
324 * insn_get_displacement() - Get the displacement of instruction
325 * @insn: &struct insn containing instruction
326 *
327 * If necessary, first collects the instruction up to and including the
328 * SIB byte.
329 * Displacement value is sign-expanded.
330 */
331void insn_get_displacement(struct insn *insn)
332{
333 insn_byte_t mod, rm, base;
334
335 if (insn->displacement.got)
336 return;
337 if (!insn->sib.got)
338 insn_get_sib(insn);
339 if (insn->modrm.nbytes) {
340 /*
341 * Interpreting the modrm byte:
342 * mod = 00 - no displacement fields (exceptions below)
343 * mod = 01 - 1-byte displacement field
344 * mod = 10 - displacement field is 4 bytes, or 2 bytes if
345 * address size = 2 (0x67 prefix in 32-bit mode)
346 * mod = 11 - no memory operand
347 *
348 * If address size = 2...
349 * mod = 00, r/m = 110 - displacement field is 2 bytes
350 *
351 * If address size != 2...
352 * mod != 11, r/m = 100 - SIB byte exists
353 * mod = 00, SIB base = 101 - displacement field is 4 bytes
354 * mod = 00, r/m = 101 - rip-relative addressing, displacement
355 * field is 4 bytes
356 */
357 mod = X86_MODRM_MOD(insn->modrm.value);
358 rm = X86_MODRM_RM(insn->modrm.value);
359 base = X86_SIB_BASE(insn->sib.value);
360 if (mod == 3)
361 goto out;
362 if (mod == 1) {
363 insn->displacement.value = get_next(char, insn);
364 insn->displacement.nbytes = 1;
365 } else if (insn->addr_bytes == 2) {
366 if ((mod == 0 && rm == 6) || mod == 2) {
367 insn->displacement.value =
368 get_next(short, insn);
369 insn->displacement.nbytes = 2;
370 }
371 } else {
372 if ((mod == 0 && rm == 5) || mod == 2 ||
373 (mod == 0 && base == 5)) {
374 insn->displacement.value = get_next(int, insn);
375 insn->displacement.nbytes = 4;
376 }
377 }
378 }
379out:
380 insn->displacement.got = 1;
381
382err_out:
383 return;
384}
385
386/* Decode moffset16/32/64. Return 0 if failed */
387static int __get_moffset(struct insn *insn)
388{
389 switch (insn->addr_bytes) {
390 case 2:
391 insn->moffset1.value = get_next(short, insn);
392 insn->moffset1.nbytes = 2;
393 break;
394 case 4:
395 insn->moffset1.value = get_next(int, insn);
396 insn->moffset1.nbytes = 4;
397 break;
398 case 8:
399 insn->moffset1.value = get_next(int, insn);
400 insn->moffset1.nbytes = 4;
401 insn->moffset2.value = get_next(int, insn);
402 insn->moffset2.nbytes = 4;
403 break;
404 default: /* opnd_bytes must be modified manually */
405 goto err_out;
406 }
407 insn->moffset1.got = insn->moffset2.got = 1;
408
409 return 1;
410
411err_out:
412 return 0;
413}
414
415/* Decode imm v32(Iz). Return 0 if failed */
416static int __get_immv32(struct insn *insn)
417{
418 switch (insn->opnd_bytes) {
419 case 2:
420 insn->immediate.value = get_next(short, insn);
421 insn->immediate.nbytes = 2;
422 break;
423 case 4:
424 case 8:
425 insn->immediate.value = get_next(int, insn);
426 insn->immediate.nbytes = 4;
427 break;
428 default: /* opnd_bytes must be modified manually */
429 goto err_out;
430 }
431
432 return 1;
433
434err_out:
435 return 0;
436}
437
438/* Decode imm v64(Iv/Ov), Return 0 if failed */
439static int __get_immv(struct insn *insn)
440{
441 switch (insn->opnd_bytes) {
442 case 2:
443 insn->immediate1.value = get_next(short, insn);
444 insn->immediate1.nbytes = 2;
445 break;
446 case 4:
447 insn->immediate1.value = get_next(int, insn);
448 insn->immediate1.nbytes = 4;
449 break;
450 case 8:
451 insn->immediate1.value = get_next(int, insn);
452 insn->immediate1.nbytes = 4;
453 insn->immediate2.value = get_next(int, insn);
454 insn->immediate2.nbytes = 4;
455 break;
456 default: /* opnd_bytes must be modified manually */
457 goto err_out;
458 }
459 insn->immediate1.got = insn->immediate2.got = 1;
460
461 return 1;
462err_out:
463 return 0;
464}
465
466/* Decode ptr16:16/32(Ap) */
467static int __get_immptr(struct insn *insn)
468{
469 switch (insn->opnd_bytes) {
470 case 2:
471 insn->immediate1.value = get_next(short, insn);
472 insn->immediate1.nbytes = 2;
473 break;
474 case 4:
475 insn->immediate1.value = get_next(int, insn);
476 insn->immediate1.nbytes = 4;
477 break;
478 case 8:
479 /* ptr16:64 is not exist (no segment) */
480 return 0;
481 default: /* opnd_bytes must be modified manually */
482 goto err_out;
483 }
484 insn->immediate2.value = get_next(unsigned short, insn);
485 insn->immediate2.nbytes = 2;
486 insn->immediate1.got = insn->immediate2.got = 1;
487
488 return 1;
489err_out:
490 return 0;
491}
492
493/**
494 * insn_get_immediate() - Get the immediates of instruction
495 * @insn: &struct insn containing instruction
496 *
497 * If necessary, first collects the instruction up to and including the
498 * displacement bytes.
499 * Basically, most of immediates are sign-expanded. Unsigned-value can be
500 * get by bit masking with ((1 << (nbytes * 8)) - 1)
501 */
502void insn_get_immediate(struct insn *insn)
503{
504 if (insn->immediate.got)
505 return;
506 if (!insn->displacement.got)
507 insn_get_displacement(insn);
508
509 if (inat_has_moffset(insn->attr)) {
510 if (!__get_moffset(insn))
511 goto err_out;
512 goto done;
513 }
514
515 if (!inat_has_immediate(insn->attr))
516 /* no immediates */
517 goto done;
518
519 switch (inat_immediate_size(insn->attr)) {
520 case INAT_IMM_BYTE:
521 insn->immediate.value = get_next(char, insn);
522 insn->immediate.nbytes = 1;
523 break;
524 case INAT_IMM_WORD:
525 insn->immediate.value = get_next(short, insn);
526 insn->immediate.nbytes = 2;
527 break;
528 case INAT_IMM_DWORD:
529 insn->immediate.value = get_next(int, insn);
530 insn->immediate.nbytes = 4;
531 break;
532 case INAT_IMM_QWORD:
533 insn->immediate1.value = get_next(int, insn);
534 insn->immediate1.nbytes = 4;
535 insn->immediate2.value = get_next(int, insn);
536 insn->immediate2.nbytes = 4;
537 break;
538 case INAT_IMM_PTR:
539 if (!__get_immptr(insn))
540 goto err_out;
541 break;
542 case INAT_IMM_VWORD32:
543 if (!__get_immv32(insn))
544 goto err_out;
545 break;
546 case INAT_IMM_VWORD:
547 if (!__get_immv(insn))
548 goto err_out;
549 break;
550 default:
551 /* Here, insn must have an immediate, but failed */
552 goto err_out;
553 }
554 if (inat_has_second_immediate(insn->attr)) {
555 insn->immediate2.value = get_next(char, insn);
556 insn->immediate2.nbytes = 1;
557 }
558done:
559 insn->immediate.got = 1;
560
561err_out:
562 return;
563}
564
565/**
566 * insn_get_length() - Get the length of instruction
567 * @insn: &struct insn containing instruction
568 *
569 * If necessary, first collects the instruction up to and including the
570 * immediates bytes.
571 */
572void insn_get_length(struct insn *insn)
573{
574 if (insn->length)
575 return;
576 if (!insn->immediate.got)
577 insn_get_immediate(insn);
578 insn->length = (unsigned char)((unsigned long)insn->next_byte
579 - (unsigned long)insn->kaddr);
580}
1/*
2 * x86 instruction analysis
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright (C) IBM Corporation, 2002, 2004, 2009
19 */
20
21#include <linux/string.h>
22#include <asm/inat.h>
23#include <asm/insn.h>
24
25#define get_next(t, insn) \
26 ({t r; r = *(t*)insn->next_byte; insn->next_byte += sizeof(t); r; })
27
28#define peek_next(t, insn) \
29 ({t r; r = *(t*)insn->next_byte; r; })
30
31#define peek_nbyte_next(t, insn, n) \
32 ({t r; r = *(t*)((insn)->next_byte + n); r; })
33
34/**
35 * insn_init() - initialize struct insn
36 * @insn: &struct insn to be initialized
37 * @kaddr: address (in kernel memory) of instruction (or copy thereof)
38 * @x86_64: !0 for 64-bit kernel or 64-bit app
39 */
40void insn_init(struct insn *insn, const void *kaddr, int x86_64)
41{
42 memset(insn, 0, sizeof(*insn));
43 insn->kaddr = kaddr;
44 insn->next_byte = kaddr;
45 insn->x86_64 = x86_64 ? 1 : 0;
46 insn->opnd_bytes = 4;
47 if (x86_64)
48 insn->addr_bytes = 8;
49 else
50 insn->addr_bytes = 4;
51}
52
53/**
54 * insn_get_prefixes - scan x86 instruction prefix bytes
55 * @insn: &struct insn containing instruction
56 *
57 * Populates the @insn->prefixes bitmap, and updates @insn->next_byte
58 * to point to the (first) opcode. No effect if @insn->prefixes.got
59 * is already set.
60 */
61void insn_get_prefixes(struct insn *insn)
62{
63 struct insn_field *prefixes = &insn->prefixes;
64 insn_attr_t attr;
65 insn_byte_t b, lb;
66 int i, nb;
67
68 if (prefixes->got)
69 return;
70
71 nb = 0;
72 lb = 0;
73 b = peek_next(insn_byte_t, insn);
74 attr = inat_get_opcode_attribute(b);
75 while (inat_is_legacy_prefix(attr)) {
76 /* Skip if same prefix */
77 for (i = 0; i < nb; i++)
78 if (prefixes->bytes[i] == b)
79 goto found;
80 if (nb == 4)
81 /* Invalid instruction */
82 break;
83 prefixes->bytes[nb++] = b;
84 if (inat_is_address_size_prefix(attr)) {
85 /* address size switches 2/4 or 4/8 */
86 if (insn->x86_64)
87 insn->addr_bytes ^= 12;
88 else
89 insn->addr_bytes ^= 6;
90 } else if (inat_is_operand_size_prefix(attr)) {
91 /* oprand size switches 2/4 */
92 insn->opnd_bytes ^= 6;
93 }
94found:
95 prefixes->nbytes++;
96 insn->next_byte++;
97 lb = b;
98 b = peek_next(insn_byte_t, insn);
99 attr = inat_get_opcode_attribute(b);
100 }
101 /* Set the last prefix */
102 if (lb && lb != insn->prefixes.bytes[3]) {
103 if (unlikely(insn->prefixes.bytes[3])) {
104 /* Swap the last prefix */
105 b = insn->prefixes.bytes[3];
106 for (i = 0; i < nb; i++)
107 if (prefixes->bytes[i] == lb)
108 prefixes->bytes[i] = b;
109 }
110 insn->prefixes.bytes[3] = lb;
111 }
112
113 /* Decode REX prefix */
114 if (insn->x86_64) {
115 b = peek_next(insn_byte_t, insn);
116 attr = inat_get_opcode_attribute(b);
117 if (inat_is_rex_prefix(attr)) {
118 insn->rex_prefix.value = b;
119 insn->rex_prefix.nbytes = 1;
120 insn->next_byte++;
121 if (X86_REX_W(b))
122 /* REX.W overrides opnd_size */
123 insn->opnd_bytes = 8;
124 }
125 }
126 insn->rex_prefix.got = 1;
127
128 /* Decode VEX prefix */
129 b = peek_next(insn_byte_t, insn);
130 attr = inat_get_opcode_attribute(b);
131 if (inat_is_vex_prefix(attr)) {
132 insn_byte_t b2 = peek_nbyte_next(insn_byte_t, insn, 1);
133 if (!insn->x86_64) {
134 /*
135 * In 32-bits mode, if the [7:6] bits (mod bits of
136 * ModRM) on the second byte are not 11b, it is
137 * LDS or LES.
138 */
139 if (X86_MODRM_MOD(b2) != 3)
140 goto vex_end;
141 }
142 insn->vex_prefix.bytes[0] = b;
143 insn->vex_prefix.bytes[1] = b2;
144 if (inat_is_vex3_prefix(attr)) {
145 b2 = peek_nbyte_next(insn_byte_t, insn, 2);
146 insn->vex_prefix.bytes[2] = b2;
147 insn->vex_prefix.nbytes = 3;
148 insn->next_byte += 3;
149 if (insn->x86_64 && X86_VEX_W(b2))
150 /* VEX.W overrides opnd_size */
151 insn->opnd_bytes = 8;
152 } else {
153 insn->vex_prefix.nbytes = 2;
154 insn->next_byte += 2;
155 }
156 }
157vex_end:
158 insn->vex_prefix.got = 1;
159
160 prefixes->got = 1;
161 return;
162}
163
164/**
165 * insn_get_opcode - collect opcode(s)
166 * @insn: &struct insn containing instruction
167 *
168 * Populates @insn->opcode, updates @insn->next_byte to point past the
169 * opcode byte(s), and set @insn->attr (except for groups).
170 * If necessary, first collects any preceding (prefix) bytes.
171 * Sets @insn->opcode.value = opcode1. No effect if @insn->opcode.got
172 * is already 1.
173 */
174void insn_get_opcode(struct insn *insn)
175{
176 struct insn_field *opcode = &insn->opcode;
177 insn_byte_t op, pfx;
178 if (opcode->got)
179 return;
180 if (!insn->prefixes.got)
181 insn_get_prefixes(insn);
182
183 /* Get first opcode */
184 op = get_next(insn_byte_t, insn);
185 opcode->bytes[0] = op;
186 opcode->nbytes = 1;
187
188 /* Check if there is VEX prefix or not */
189 if (insn_is_avx(insn)) {
190 insn_byte_t m, p;
191 m = insn_vex_m_bits(insn);
192 p = insn_vex_p_bits(insn);
193 insn->attr = inat_get_avx_attribute(op, m, p);
194 if (!inat_accept_vex(insn->attr))
195 insn->attr = 0; /* This instruction is bad */
196 goto end; /* VEX has only 1 byte for opcode */
197 }
198
199 insn->attr = inat_get_opcode_attribute(op);
200 while (inat_is_escape(insn->attr)) {
201 /* Get escaped opcode */
202 op = get_next(insn_byte_t, insn);
203 opcode->bytes[opcode->nbytes++] = op;
204 pfx = insn_last_prefix(insn);
205 insn->attr = inat_get_escape_attribute(op, pfx, insn->attr);
206 }
207 if (inat_must_vex(insn->attr))
208 insn->attr = 0; /* This instruction is bad */
209end:
210 opcode->got = 1;
211}
212
213/**
214 * insn_get_modrm - collect ModRM byte, if any
215 * @insn: &struct insn containing instruction
216 *
217 * Populates @insn->modrm and updates @insn->next_byte to point past the
218 * ModRM byte, if any. If necessary, first collects the preceding bytes
219 * (prefixes and opcode(s)). No effect if @insn->modrm.got is already 1.
220 */
221void insn_get_modrm(struct insn *insn)
222{
223 struct insn_field *modrm = &insn->modrm;
224 insn_byte_t pfx, mod;
225 if (modrm->got)
226 return;
227 if (!insn->opcode.got)
228 insn_get_opcode(insn);
229
230 if (inat_has_modrm(insn->attr)) {
231 mod = get_next(insn_byte_t, insn);
232 modrm->value = mod;
233 modrm->nbytes = 1;
234 if (inat_is_group(insn->attr)) {
235 pfx = insn_last_prefix(insn);
236 insn->attr = inat_get_group_attribute(mod, pfx,
237 insn->attr);
238 }
239 }
240
241 if (insn->x86_64 && inat_is_force64(insn->attr))
242 insn->opnd_bytes = 8;
243 modrm->got = 1;
244}
245
246
247/**
248 * insn_rip_relative() - Does instruction use RIP-relative addressing mode?
249 * @insn: &struct insn containing instruction
250 *
251 * If necessary, first collects the instruction up to and including the
252 * ModRM byte. No effect if @insn->x86_64 is 0.
253 */
254int insn_rip_relative(struct insn *insn)
255{
256 struct insn_field *modrm = &insn->modrm;
257
258 if (!insn->x86_64)
259 return 0;
260 if (!modrm->got)
261 insn_get_modrm(insn);
262 /*
263 * For rip-relative instructions, the mod field (top 2 bits)
264 * is zero and the r/m field (bottom 3 bits) is 0x5.
265 */
266 return (modrm->nbytes && (modrm->value & 0xc7) == 0x5);
267}
268
269/**
270 * insn_get_sib() - Get the SIB byte of instruction
271 * @insn: &struct insn containing instruction
272 *
273 * If necessary, first collects the instruction up to and including the
274 * ModRM byte.
275 */
276void insn_get_sib(struct insn *insn)
277{
278 insn_byte_t modrm;
279
280 if (insn->sib.got)
281 return;
282 if (!insn->modrm.got)
283 insn_get_modrm(insn);
284 if (insn->modrm.nbytes) {
285 modrm = (insn_byte_t)insn->modrm.value;
286 if (insn->addr_bytes != 2 &&
287 X86_MODRM_MOD(modrm) != 3 && X86_MODRM_RM(modrm) == 4) {
288 insn->sib.value = get_next(insn_byte_t, insn);
289 insn->sib.nbytes = 1;
290 }
291 }
292 insn->sib.got = 1;
293}
294
295
296/**
297 * insn_get_displacement() - Get the displacement of instruction
298 * @insn: &struct insn containing instruction
299 *
300 * If necessary, first collects the instruction up to and including the
301 * SIB byte.
302 * Displacement value is sign-expanded.
303 */
304void insn_get_displacement(struct insn *insn)
305{
306 insn_byte_t mod, rm, base;
307
308 if (insn->displacement.got)
309 return;
310 if (!insn->sib.got)
311 insn_get_sib(insn);
312 if (insn->modrm.nbytes) {
313 /*
314 * Interpreting the modrm byte:
315 * mod = 00 - no displacement fields (exceptions below)
316 * mod = 01 - 1-byte displacement field
317 * mod = 10 - displacement field is 4 bytes, or 2 bytes if
318 * address size = 2 (0x67 prefix in 32-bit mode)
319 * mod = 11 - no memory operand
320 *
321 * If address size = 2...
322 * mod = 00, r/m = 110 - displacement field is 2 bytes
323 *
324 * If address size != 2...
325 * mod != 11, r/m = 100 - SIB byte exists
326 * mod = 00, SIB base = 101 - displacement field is 4 bytes
327 * mod = 00, r/m = 101 - rip-relative addressing, displacement
328 * field is 4 bytes
329 */
330 mod = X86_MODRM_MOD(insn->modrm.value);
331 rm = X86_MODRM_RM(insn->modrm.value);
332 base = X86_SIB_BASE(insn->sib.value);
333 if (mod == 3)
334 goto out;
335 if (mod == 1) {
336 insn->displacement.value = get_next(char, insn);
337 insn->displacement.nbytes = 1;
338 } else if (insn->addr_bytes == 2) {
339 if ((mod == 0 && rm == 6) || mod == 2) {
340 insn->displacement.value =
341 get_next(short, insn);
342 insn->displacement.nbytes = 2;
343 }
344 } else {
345 if ((mod == 0 && rm == 5) || mod == 2 ||
346 (mod == 0 && base == 5)) {
347 insn->displacement.value = get_next(int, insn);
348 insn->displacement.nbytes = 4;
349 }
350 }
351 }
352out:
353 insn->displacement.got = 1;
354}
355
356/* Decode moffset16/32/64 */
357static void __get_moffset(struct insn *insn)
358{
359 switch (insn->addr_bytes) {
360 case 2:
361 insn->moffset1.value = get_next(short, insn);
362 insn->moffset1.nbytes = 2;
363 break;
364 case 4:
365 insn->moffset1.value = get_next(int, insn);
366 insn->moffset1.nbytes = 4;
367 break;
368 case 8:
369 insn->moffset1.value = get_next(int, insn);
370 insn->moffset1.nbytes = 4;
371 insn->moffset2.value = get_next(int, insn);
372 insn->moffset2.nbytes = 4;
373 break;
374 }
375 insn->moffset1.got = insn->moffset2.got = 1;
376}
377
378/* Decode imm v32(Iz) */
379static void __get_immv32(struct insn *insn)
380{
381 switch (insn->opnd_bytes) {
382 case 2:
383 insn->immediate.value = get_next(short, insn);
384 insn->immediate.nbytes = 2;
385 break;
386 case 4:
387 case 8:
388 insn->immediate.value = get_next(int, insn);
389 insn->immediate.nbytes = 4;
390 break;
391 }
392}
393
394/* Decode imm v64(Iv/Ov) */
395static void __get_immv(struct insn *insn)
396{
397 switch (insn->opnd_bytes) {
398 case 2:
399 insn->immediate1.value = get_next(short, insn);
400 insn->immediate1.nbytes = 2;
401 break;
402 case 4:
403 insn->immediate1.value = get_next(int, insn);
404 insn->immediate1.nbytes = 4;
405 break;
406 case 8:
407 insn->immediate1.value = get_next(int, insn);
408 insn->immediate1.nbytes = 4;
409 insn->immediate2.value = get_next(int, insn);
410 insn->immediate2.nbytes = 4;
411 break;
412 }
413 insn->immediate1.got = insn->immediate2.got = 1;
414}
415
416/* Decode ptr16:16/32(Ap) */
417static void __get_immptr(struct insn *insn)
418{
419 switch (insn->opnd_bytes) {
420 case 2:
421 insn->immediate1.value = get_next(short, insn);
422 insn->immediate1.nbytes = 2;
423 break;
424 case 4:
425 insn->immediate1.value = get_next(int, insn);
426 insn->immediate1.nbytes = 4;
427 break;
428 case 8:
429 /* ptr16:64 is not exist (no segment) */
430 return;
431 }
432 insn->immediate2.value = get_next(unsigned short, insn);
433 insn->immediate2.nbytes = 2;
434 insn->immediate1.got = insn->immediate2.got = 1;
435}
436
437/**
438 * insn_get_immediate() - Get the immediates of instruction
439 * @insn: &struct insn containing instruction
440 *
441 * If necessary, first collects the instruction up to and including the
442 * displacement bytes.
443 * Basically, most of immediates are sign-expanded. Unsigned-value can be
444 * get by bit masking with ((1 << (nbytes * 8)) - 1)
445 */
446void insn_get_immediate(struct insn *insn)
447{
448 if (insn->immediate.got)
449 return;
450 if (!insn->displacement.got)
451 insn_get_displacement(insn);
452
453 if (inat_has_moffset(insn->attr)) {
454 __get_moffset(insn);
455 goto done;
456 }
457
458 if (!inat_has_immediate(insn->attr))
459 /* no immediates */
460 goto done;
461
462 switch (inat_immediate_size(insn->attr)) {
463 case INAT_IMM_BYTE:
464 insn->immediate.value = get_next(char, insn);
465 insn->immediate.nbytes = 1;
466 break;
467 case INAT_IMM_WORD:
468 insn->immediate.value = get_next(short, insn);
469 insn->immediate.nbytes = 2;
470 break;
471 case INAT_IMM_DWORD:
472 insn->immediate.value = get_next(int, insn);
473 insn->immediate.nbytes = 4;
474 break;
475 case INAT_IMM_QWORD:
476 insn->immediate1.value = get_next(int, insn);
477 insn->immediate1.nbytes = 4;
478 insn->immediate2.value = get_next(int, insn);
479 insn->immediate2.nbytes = 4;
480 break;
481 case INAT_IMM_PTR:
482 __get_immptr(insn);
483 break;
484 case INAT_IMM_VWORD32:
485 __get_immv32(insn);
486 break;
487 case INAT_IMM_VWORD:
488 __get_immv(insn);
489 break;
490 default:
491 break;
492 }
493 if (inat_has_second_immediate(insn->attr)) {
494 insn->immediate2.value = get_next(char, insn);
495 insn->immediate2.nbytes = 1;
496 }
497done:
498 insn->immediate.got = 1;
499}
500
501/**
502 * insn_get_length() - Get the length of instruction
503 * @insn: &struct insn containing instruction
504 *
505 * If necessary, first collects the instruction up to and including the
506 * immediates bytes.
507 */
508void insn_get_length(struct insn *insn)
509{
510 if (insn->length)
511 return;
512 if (!insn->immediate.got)
513 insn_get_immediate(insn);
514 insn->length = (unsigned char)((unsigned long)insn->next_byte
515 - (unsigned long)insn->kaddr);
516}