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442f04c3 JP |
1 | /* |
2 | * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version 2 | |
7 | * of the License, or (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, see <http://www.gnu.org/licenses/>. | |
16 | */ | |
17 | ||
18 | #include <stdio.h> | |
19 | #include <stdlib.h> | |
20 | ||
21 | #define unlikely(cond) (cond) | |
6a77cff8 JP |
22 | #include <asm/insn.h> |
23 | #include "lib/inat.c" | |
24 | #include "lib/insn.c" | |
442f04c3 JP |
25 | |
26 | #include "../../elf.h" | |
27 | #include "../../arch.h" | |
28 | #include "../../warn.h" | |
29 | ||
baa41469 JP |
30 | static unsigned char op_to_cfi_reg[][2] = { |
31 | {CFI_AX, CFI_R8}, | |
32 | {CFI_CX, CFI_R9}, | |
33 | {CFI_DX, CFI_R10}, | |
34 | {CFI_BX, CFI_R11}, | |
35 | {CFI_SP, CFI_R12}, | |
36 | {CFI_BP, CFI_R13}, | |
37 | {CFI_SI, CFI_R14}, | |
38 | {CFI_DI, CFI_R15}, | |
39 | }; | |
40 | ||
442f04c3 JP |
41 | static int is_x86_64(struct elf *elf) |
42 | { | |
43 | switch (elf->ehdr.e_machine) { | |
44 | case EM_X86_64: | |
45 | return 1; | |
46 | case EM_386: | |
47 | return 0; | |
48 | default: | |
49 | WARN("unexpected ELF machine type %d", elf->ehdr.e_machine); | |
50 | return -1; | |
51 | } | |
52 | } | |
53 | ||
baa41469 JP |
54 | bool arch_callee_saved_reg(unsigned char reg) |
55 | { | |
56 | switch (reg) { | |
57 | case CFI_BP: | |
58 | case CFI_BX: | |
59 | case CFI_R12: | |
60 | case CFI_R13: | |
61 | case CFI_R14: | |
62 | case CFI_R15: | |
63 | return true; | |
64 | ||
65 | case CFI_AX: | |
66 | case CFI_CX: | |
67 | case CFI_DX: | |
68 | case CFI_SI: | |
69 | case CFI_DI: | |
70 | case CFI_SP: | |
71 | case CFI_R8: | |
72 | case CFI_R9: | |
73 | case CFI_R10: | |
74 | case CFI_R11: | |
75 | case CFI_RA: | |
76 | default: | |
77 | return false; | |
78 | } | |
79 | } | |
80 | ||
442f04c3 JP |
81 | int arch_decode_instruction(struct elf *elf, struct section *sec, |
82 | unsigned long offset, unsigned int maxlen, | |
83 | unsigned int *len, unsigned char *type, | |
baa41469 | 84 | unsigned long *immediate, struct stack_op *op) |
442f04c3 JP |
85 | { |
86 | struct insn insn; | |
baa41469 JP |
87 | int x86_64, sign; |
88 | unsigned char op1, op2, rex = 0, rex_b = 0, rex_r = 0, rex_w = 0, | |
dd88a0a0 JP |
89 | rex_x = 0, modrm = 0, modrm_mod = 0, modrm_rm = 0, |
90 | modrm_reg = 0, sib = 0; | |
442f04c3 JP |
91 | |
92 | x86_64 = is_x86_64(elf); | |
93 | if (x86_64 == -1) | |
94 | return -1; | |
95 | ||
baa41469 | 96 | insn_init(&insn, sec->data->d_buf + offset, maxlen, x86_64); |
442f04c3 | 97 | insn_get_length(&insn); |
442f04c3 JP |
98 | |
99 | if (!insn_complete(&insn)) { | |
100 | WARN_FUNC("can't decode instruction", sec, offset); | |
101 | return -1; | |
102 | } | |
103 | ||
104 | *len = insn.length; | |
105 | *type = INSN_OTHER; | |
106 | ||
107 | if (insn.vex_prefix.nbytes) | |
108 | return 0; | |
109 | ||
110 | op1 = insn.opcode.bytes[0]; | |
111 | op2 = insn.opcode.bytes[1]; | |
112 | ||
baa41469 JP |
113 | if (insn.rex_prefix.nbytes) { |
114 | rex = insn.rex_prefix.bytes[0]; | |
115 | rex_w = X86_REX_W(rex) >> 3; | |
116 | rex_r = X86_REX_R(rex) >> 2; | |
dd88a0a0 | 117 | rex_x = X86_REX_X(rex) >> 1; |
baa41469 JP |
118 | rex_b = X86_REX_B(rex); |
119 | } | |
120 | ||
121 | if (insn.modrm.nbytes) { | |
122 | modrm = insn.modrm.bytes[0]; | |
123 | modrm_mod = X86_MODRM_MOD(modrm); | |
124 | modrm_reg = X86_MODRM_REG(modrm); | |
125 | modrm_rm = X86_MODRM_RM(modrm); | |
126 | } | |
127 | ||
128 | if (insn.sib.nbytes) | |
129 | sib = insn.sib.bytes[0]; | |
130 | ||
442f04c3 | 131 | switch (op1) { |
baa41469 JP |
132 | |
133 | case 0x1: | |
134 | case 0x29: | |
135 | if (rex_w && !rex_b && modrm_mod == 3 && modrm_rm == 4) { | |
136 | ||
137 | /* add/sub reg, %rsp */ | |
138 | *type = INSN_STACK; | |
139 | op->src.type = OP_SRC_ADD; | |
140 | op->src.reg = op_to_cfi_reg[modrm_reg][rex_r]; | |
e7e83dd3 | 141 | op->dest.type = OP_DEST_REG; |
baa41469 JP |
142 | op->dest.reg = CFI_SP; |
143 | } | |
144 | break; | |
145 | ||
146 | case 0x50 ... 0x57: | |
147 | ||
148 | /* push reg */ | |
149 | *type = INSN_STACK; | |
150 | op->src.type = OP_SRC_REG; | |
151 | op->src.reg = op_to_cfi_reg[op1 & 0x7][rex_b]; | |
152 | op->dest.type = OP_DEST_PUSH; | |
153 | ||
442f04c3 JP |
154 | break; |
155 | ||
baa41469 JP |
156 | case 0x58 ... 0x5f: |
157 | ||
158 | /* pop reg */ | |
159 | *type = INSN_STACK; | |
160 | op->src.type = OP_SRC_POP; | |
161 | op->dest.type = OP_DEST_REG; | |
162 | op->dest.reg = op_to_cfi_reg[op1 & 0x7][rex_b]; | |
163 | ||
164 | break; | |
165 | ||
166 | case 0x68: | |
167 | case 0x6a: | |
168 | /* push immediate */ | |
169 | *type = INSN_STACK; | |
170 | op->src.type = OP_SRC_CONST; | |
171 | op->dest.type = OP_DEST_PUSH; | |
442f04c3 JP |
172 | break; |
173 | ||
174 | case 0x70 ... 0x7f: | |
175 | *type = INSN_JUMP_CONDITIONAL; | |
176 | break; | |
177 | ||
baa41469 JP |
178 | case 0x81: |
179 | case 0x83: | |
180 | if (rex != 0x48) | |
181 | break; | |
182 | ||
183 | if (modrm == 0xe4) { | |
184 | /* and imm, %rsp */ | |
185 | *type = INSN_STACK; | |
186 | op->src.type = OP_SRC_AND; | |
187 | op->src.reg = CFI_SP; | |
188 | op->src.offset = insn.immediate.value; | |
189 | op->dest.type = OP_DEST_REG; | |
190 | op->dest.reg = CFI_SP; | |
191 | break; | |
192 | } | |
193 | ||
194 | if (modrm == 0xc4) | |
195 | sign = 1; | |
196 | else if (modrm == 0xec) | |
197 | sign = -1; | |
198 | else | |
199 | break; | |
200 | ||
201 | /* add/sub imm, %rsp */ | |
202 | *type = INSN_STACK; | |
203 | op->src.type = OP_SRC_ADD; | |
204 | op->src.reg = CFI_SP; | |
205 | op->src.offset = insn.immediate.value * sign; | |
206 | op->dest.type = OP_DEST_REG; | |
207 | op->dest.reg = CFI_SP; | |
208 | break; | |
209 | ||
442f04c3 | 210 | case 0x89: |
0d0970ee | 211 | if (rex_w && !rex_r && modrm_mod == 3 && modrm_reg == 4) { |
baa41469 | 212 | |
0d0970ee | 213 | /* mov %rsp, reg */ |
baa41469 JP |
214 | *type = INSN_STACK; |
215 | op->src.type = OP_SRC_REG; | |
216 | op->src.reg = CFI_SP; | |
217 | op->dest.type = OP_DEST_REG; | |
0d0970ee | 218 | op->dest.reg = op_to_cfi_reg[modrm_rm][rex_b]; |
baa41469 JP |
219 | break; |
220 | } | |
dd88a0a0 JP |
221 | |
222 | if (rex_w && !rex_b && modrm_mod == 3 && modrm_rm == 4) { | |
223 | ||
224 | /* mov reg, %rsp */ | |
225 | *type = INSN_STACK; | |
226 | op->src.type = OP_SRC_REG; | |
227 | op->src.reg = op_to_cfi_reg[modrm_reg][rex_r]; | |
228 | op->dest.type = OP_DEST_REG; | |
229 | op->dest.reg = CFI_SP; | |
230 | break; | |
231 | } | |
232 | ||
baa41469 JP |
233 | /* fallthrough */ |
234 | case 0x88: | |
235 | if (!rex_b && | |
236 | (modrm_mod == 1 || modrm_mod == 2) && modrm_rm == 5) { | |
237 | ||
238 | /* mov reg, disp(%rbp) */ | |
239 | *type = INSN_STACK; | |
240 | op->src.type = OP_SRC_REG; | |
241 | op->src.reg = op_to_cfi_reg[modrm_reg][rex_r]; | |
242 | op->dest.type = OP_DEST_REG_INDIRECT; | |
243 | op->dest.reg = CFI_BP; | |
244 | op->dest.offset = insn.displacement.value; | |
245 | ||
246 | } else if (rex_w && !rex_b && modrm_rm == 4 && sib == 0x24) { | |
247 | ||
248 | /* mov reg, disp(%rsp) */ | |
249 | *type = INSN_STACK; | |
250 | op->src.type = OP_SRC_REG; | |
251 | op->src.reg = op_to_cfi_reg[modrm_reg][rex_r]; | |
252 | op->dest.type = OP_DEST_REG_INDIRECT; | |
253 | op->dest.reg = CFI_SP; | |
254 | op->dest.offset = insn.displacement.value; | |
255 | } | |
256 | ||
257 | break; | |
258 | ||
259 | case 0x8b: | |
260 | if (rex_w && !rex_b && modrm_mod == 1 && modrm_rm == 5) { | |
261 | ||
262 | /* mov disp(%rbp), reg */ | |
263 | *type = INSN_STACK; | |
264 | op->src.type = OP_SRC_REG_INDIRECT; | |
265 | op->src.reg = CFI_BP; | |
266 | op->src.offset = insn.displacement.value; | |
267 | op->dest.type = OP_DEST_REG; | |
268 | op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r]; | |
269 | ||
270 | } else if (rex_w && !rex_b && sib == 0x24 && | |
271 | modrm_mod != 3 && modrm_rm == 4) { | |
272 | ||
273 | /* mov disp(%rsp), reg */ | |
274 | *type = INSN_STACK; | |
275 | op->src.type = OP_SRC_REG_INDIRECT; | |
276 | op->src.reg = CFI_SP; | |
277 | op->src.offset = insn.displacement.value; | |
278 | op->dest.type = OP_DEST_REG; | |
279 | op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r]; | |
280 | } | |
281 | ||
442f04c3 JP |
282 | break; |
283 | ||
2cc17fda | 284 | case 0x8d: |
dd88a0a0 | 285 | if (sib == 0x24 && rex_w && !rex_b && !rex_x) { |
baa41469 | 286 | |
baa41469 | 287 | *type = INSN_STACK; |
607a4029 JP |
288 | if (!insn.displacement.value) { |
289 | /* lea (%rsp), reg */ | |
290 | op->src.type = OP_SRC_REG; | |
291 | } else { | |
292 | /* lea disp(%rsp), reg */ | |
293 | op->src.type = OP_SRC_ADD; | |
294 | op->src.offset = insn.displacement.value; | |
295 | } | |
dd88a0a0 | 296 | op->src.reg = CFI_SP; |
baa41469 | 297 | op->dest.type = OP_DEST_REG; |
dd88a0a0 | 298 | op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r]; |
baa41469 | 299 | |
dd88a0a0 | 300 | } else if (rex == 0x48 && modrm == 0x65) { |
5b8de48e | 301 | |
dd88a0a0 | 302 | /* lea disp(%rbp), %rsp */ |
5b8de48e JP |
303 | *type = INSN_STACK; |
304 | op->src.type = OP_SRC_ADD; | |
dd88a0a0 | 305 | op->src.reg = CFI_BP; |
5b8de48e JP |
306 | op->src.offset = insn.displacement.value; |
307 | op->dest.type = OP_DEST_REG; | |
308 | op->dest.reg = CFI_SP; | |
5b8de48e | 309 | |
dd88a0a0 JP |
310 | } else if (rex == 0x49 && modrm == 0x62 && |
311 | insn.displacement.value == -8) { | |
baa41469 JP |
312 | |
313 | /* | |
314 | * lea -0x8(%r10), %rsp | |
315 | * | |
316 | * Restoring rsp back to its original value after a | |
317 | * stack realignment. | |
318 | */ | |
319 | *type = INSN_STACK; | |
320 | op->src.type = OP_SRC_ADD; | |
321 | op->src.reg = CFI_R10; | |
322 | op->src.offset = -8; | |
323 | op->dest.type = OP_DEST_REG; | |
324 | op->dest.reg = CFI_SP; | |
baa41469 | 325 | |
dd88a0a0 JP |
326 | } else if (rex == 0x49 && modrm == 0x65 && |
327 | insn.displacement.value == -16) { | |
baa41469 JP |
328 | |
329 | /* | |
330 | * lea -0x10(%r13), %rsp | |
331 | * | |
332 | * Restoring rsp back to its original value after a | |
333 | * stack realignment. | |
334 | */ | |
335 | *type = INSN_STACK; | |
336 | op->src.type = OP_SRC_ADD; | |
337 | op->src.reg = CFI_R13; | |
338 | op->src.offset = -16; | |
339 | op->dest.type = OP_DEST_REG; | |
340 | op->dest.reg = CFI_SP; | |
baa41469 JP |
341 | } |
342 | ||
343 | break; | |
344 | ||
345 | case 0x8f: | |
346 | /* pop to mem */ | |
347 | *type = INSN_STACK; | |
348 | op->src.type = OP_SRC_POP; | |
349 | op->dest.type = OP_DEST_MEM; | |
2cc17fda JP |
350 | break; |
351 | ||
442f04c3 JP |
352 | case 0x90: |
353 | *type = INSN_NOP; | |
354 | break; | |
355 | ||
baa41469 JP |
356 | case 0x9c: |
357 | /* pushf */ | |
358 | *type = INSN_STACK; | |
359 | op->src.type = OP_SRC_CONST; | |
360 | op->dest.type = OP_DEST_PUSH; | |
361 | break; | |
362 | ||
363 | case 0x9d: | |
364 | /* popf */ | |
365 | *type = INSN_STACK; | |
366 | op->src.type = OP_SRC_POP; | |
367 | op->dest.type = OP_DEST_MEM; | |
368 | break; | |
369 | ||
442f04c3 | 370 | case 0x0f: |
baa41469 | 371 | |
649ea4d5 JP |
372 | if (op2 >= 0x80 && op2 <= 0x8f) { |
373 | ||
442f04c3 | 374 | *type = INSN_JUMP_CONDITIONAL; |
649ea4d5 JP |
375 | |
376 | } else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 || | |
377 | op2 == 0x35) { | |
baa41469 | 378 | |
442f04c3 JP |
379 | /* sysenter, sysret */ |
380 | *type = INSN_CONTEXT_SWITCH; | |
baa41469 | 381 | |
649ea4d5 JP |
382 | } else if (op2 == 0x0b || op2 == 0xb9) { |
383 | ||
384 | /* ud2 */ | |
385 | *type = INSN_BUG; | |
386 | ||
387 | } else if (op2 == 0x0d || op2 == 0x1f) { | |
baa41469 | 388 | |
442f04c3 JP |
389 | /* nopl/nopw */ |
390 | *type = INSN_NOP; | |
baa41469 | 391 | |
649ea4d5 | 392 | } else if (op2 == 0xa0 || op2 == 0xa8) { |
baa41469 JP |
393 | |
394 | /* push fs/gs */ | |
395 | *type = INSN_STACK; | |
396 | op->src.type = OP_SRC_CONST; | |
397 | op->dest.type = OP_DEST_PUSH; | |
398 | ||
399 | } else if (op2 == 0xa1 || op2 == 0xa9) { | |
400 | ||
401 | /* pop fs/gs */ | |
402 | *type = INSN_STACK; | |
403 | op->src.type = OP_SRC_POP; | |
404 | op->dest.type = OP_DEST_MEM; | |
405 | } | |
442f04c3 JP |
406 | |
407 | break; | |
408 | ||
baa41469 JP |
409 | case 0xc9: |
410 | /* | |
411 | * leave | |
412 | * | |
413 | * equivalent to: | |
414 | * mov bp, sp | |
415 | * pop bp | |
416 | */ | |
417 | *type = INSN_STACK; | |
418 | op->dest.type = OP_DEST_LEAVE; | |
419 | ||
442f04c3 JP |
420 | break; |
421 | ||
baa41469 JP |
422 | case 0xe3: |
423 | /* jecxz/jrcxz */ | |
442f04c3 JP |
424 | *type = INSN_JUMP_CONDITIONAL; |
425 | break; | |
426 | ||
427 | case 0xe9: | |
428 | case 0xeb: | |
429 | *type = INSN_JUMP_UNCONDITIONAL; | |
430 | break; | |
431 | ||
432 | case 0xc2: | |
433 | case 0xc3: | |
434 | *type = INSN_RETURN; | |
435 | break; | |
436 | ||
442f04c3 JP |
437 | case 0xca: /* retf */ |
438 | case 0xcb: /* retf */ | |
b5b46c47 | 439 | case 0xcf: /* iret */ |
442f04c3 JP |
440 | *type = INSN_CONTEXT_SWITCH; |
441 | break; | |
442 | ||
443 | case 0xe8: | |
444 | *type = INSN_CALL; | |
445 | break; | |
446 | ||
447 | case 0xff: | |
baa41469 JP |
448 | if (modrm_reg == 2 || modrm_reg == 3) |
449 | ||
442f04c3 | 450 | *type = INSN_CALL_DYNAMIC; |
baa41469 JP |
451 | |
452 | else if (modrm_reg == 4) | |
453 | ||
442f04c3 | 454 | *type = INSN_JUMP_DYNAMIC; |
baa41469 JP |
455 | |
456 | else if (modrm_reg == 5) | |
457 | ||
458 | /* jmpf */ | |
442f04c3 JP |
459 | *type = INSN_CONTEXT_SWITCH; |
460 | ||
baa41469 JP |
461 | else if (modrm_reg == 6) { |
462 | ||
463 | /* push from mem */ | |
464 | *type = INSN_STACK; | |
465 | op->src.type = OP_SRC_CONST; | |
466 | op->dest.type = OP_DEST_PUSH; | |
467 | } | |
468 | ||
442f04c3 JP |
469 | break; |
470 | ||
471 | default: | |
472 | break; | |
473 | } | |
474 | ||
475 | *immediate = insn.immediate.nbytes ? insn.immediate.value : 0; | |
476 | ||
477 | return 0; | |
478 | } | |
baa41469 JP |
479 | |
480 | void arch_initial_func_cfi_state(struct cfi_state *state) | |
481 | { | |
482 | int i; | |
483 | ||
484 | for (i = 0; i < CFI_NUM_REGS; i++) { | |
485 | state->regs[i].base = CFI_UNDEFINED; | |
486 | state->regs[i].offset = 0; | |
487 | } | |
488 | ||
489 | /* initial CFA (call frame address) */ | |
490 | state->cfa.base = CFI_SP; | |
491 | state->cfa.offset = 8; | |
492 | ||
493 | /* initial RA (return address) */ | |
494 | state->regs[16].base = CFI_CFA; | |
495 | state->regs[16].offset = -8; | |
496 | } |