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dcc914f4 JP |
1 | /* |
2 | * Copyright (C) 2015-2017 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 <string.h> | |
19 | #include <stdlib.h> | |
20 | ||
21 | #include "check.h" | |
22 | #include "elf.h" | |
23 | #include "special.h" | |
24 | #include "arch.h" | |
25 | #include "warn.h" | |
26 | ||
27 | #include <linux/hashtable.h> | |
28 | #include <linux/kernel.h> | |
29 | ||
dcc914f4 JP |
30 | struct alternative { |
31 | struct list_head list; | |
32 | struct instruction *insn; | |
33 | }; | |
34 | ||
35 | const char *objname; | |
867ac9d7 | 36 | static bool no_fp; |
baa41469 | 37 | struct cfi_state initial_func_cfi; |
dcc914f4 | 38 | |
627fce14 JP |
39 | struct instruction *find_insn(struct objtool_file *file, |
40 | struct section *sec, unsigned long offset) | |
dcc914f4 JP |
41 | { |
42 | struct instruction *insn; | |
43 | ||
44 | hash_for_each_possible(file->insn_hash, insn, hash, offset) | |
45 | if (insn->sec == sec && insn->offset == offset) | |
46 | return insn; | |
47 | ||
48 | return NULL; | |
49 | } | |
50 | ||
51 | static struct instruction *next_insn_same_sec(struct objtool_file *file, | |
52 | struct instruction *insn) | |
53 | { | |
54 | struct instruction *next = list_next_entry(insn, list); | |
55 | ||
baa41469 | 56 | if (!next || &next->list == &file->insn_list || next->sec != insn->sec) |
dcc914f4 JP |
57 | return NULL; |
58 | ||
59 | return next; | |
60 | } | |
61 | ||
dcc914f4 JP |
62 | #define func_for_each_insn(file, func, insn) \ |
63 | for (insn = find_insn(file, func->sec, func->offset); \ | |
64 | insn && &insn->list != &file->insn_list && \ | |
65 | insn->sec == func->sec && \ | |
66 | insn->offset < func->offset + func->len; \ | |
67 | insn = list_next_entry(insn, list)) | |
68 | ||
69 | #define func_for_each_insn_continue_reverse(file, func, insn) \ | |
70 | for (insn = list_prev_entry(insn, list); \ | |
71 | &insn->list != &file->insn_list && \ | |
72 | insn->sec == func->sec && insn->offset >= func->offset; \ | |
73 | insn = list_prev_entry(insn, list)) | |
74 | ||
75 | #define sec_for_each_insn_from(file, insn) \ | |
76 | for (; insn; insn = next_insn_same_sec(file, insn)) | |
77 | ||
baa41469 JP |
78 | #define sec_for_each_insn_continue(file, insn) \ |
79 | for (insn = next_insn_same_sec(file, insn); insn; \ | |
80 | insn = next_insn_same_sec(file, insn)) | |
dcc914f4 JP |
81 | |
82 | /* | |
83 | * Check if the function has been manually whitelisted with the | |
84 | * STACK_FRAME_NON_STANDARD macro, or if it should be automatically whitelisted | |
85 | * due to its use of a context switching instruction. | |
86 | */ | |
87 | static bool ignore_func(struct objtool_file *file, struct symbol *func) | |
88 | { | |
89 | struct rela *rela; | |
dcc914f4 JP |
90 | |
91 | /* check for STACK_FRAME_NON_STANDARD */ | |
92 | if (file->whitelist && file->whitelist->rela) | |
93 | list_for_each_entry(rela, &file->whitelist->rela->rela_list, list) { | |
94 | if (rela->sym->type == STT_SECTION && | |
95 | rela->sym->sec == func->sec && | |
96 | rela->addend == func->offset) | |
97 | return true; | |
98 | if (rela->sym->type == STT_FUNC && rela->sym == func) | |
99 | return true; | |
100 | } | |
101 | ||
dcc914f4 JP |
102 | return false; |
103 | } | |
104 | ||
105 | /* | |
106 | * This checks to see if the given function is a "noreturn" function. | |
107 | * | |
108 | * For global functions which are outside the scope of this object file, we | |
109 | * have to keep a manual list of them. | |
110 | * | |
111 | * For local functions, we have to detect them manually by simply looking for | |
112 | * the lack of a return instruction. | |
113 | * | |
114 | * Returns: | |
115 | * -1: error | |
116 | * 0: no dead end | |
117 | * 1: dead end | |
118 | */ | |
119 | static int __dead_end_function(struct objtool_file *file, struct symbol *func, | |
120 | int recursion) | |
121 | { | |
122 | int i; | |
123 | struct instruction *insn; | |
124 | bool empty = true; | |
125 | ||
126 | /* | |
127 | * Unfortunately these have to be hard coded because the noreturn | |
128 | * attribute isn't provided in ELF data. | |
129 | */ | |
130 | static const char * const global_noreturns[] = { | |
131 | "__stack_chk_fail", | |
132 | "panic", | |
133 | "do_exit", | |
134 | "do_task_dead", | |
135 | "__module_put_and_exit", | |
136 | "complete_and_exit", | |
137 | "kvm_spurious_fault", | |
138 | "__reiserfs_panic", | |
139 | "lbug_with_loc", | |
140 | "fortify_panic", | |
141 | }; | |
142 | ||
143 | if (func->bind == STB_WEAK) | |
144 | return 0; | |
145 | ||
146 | if (func->bind == STB_GLOBAL) | |
147 | for (i = 0; i < ARRAY_SIZE(global_noreturns); i++) | |
148 | if (!strcmp(func->name, global_noreturns[i])) | |
149 | return 1; | |
150 | ||
151 | if (!func->sec) | |
152 | return 0; | |
153 | ||
154 | func_for_each_insn(file, func, insn) { | |
155 | empty = false; | |
156 | ||
157 | if (insn->type == INSN_RETURN) | |
158 | return 0; | |
159 | } | |
160 | ||
161 | if (empty) | |
162 | return 0; | |
163 | ||
164 | /* | |
165 | * A function can have a sibling call instead of a return. In that | |
166 | * case, the function's dead-end status depends on whether the target | |
167 | * of the sibling call returns. | |
168 | */ | |
169 | func_for_each_insn(file, func, insn) { | |
170 | if (insn->sec != func->sec || | |
171 | insn->offset >= func->offset + func->len) | |
172 | break; | |
173 | ||
174 | if (insn->type == INSN_JUMP_UNCONDITIONAL) { | |
175 | struct instruction *dest = insn->jump_dest; | |
176 | struct symbol *dest_func; | |
177 | ||
178 | if (!dest) | |
179 | /* sibling call to another file */ | |
180 | return 0; | |
181 | ||
182 | if (dest->sec != func->sec || | |
183 | dest->offset < func->offset || | |
184 | dest->offset >= func->offset + func->len) { | |
185 | /* local sibling call */ | |
186 | dest_func = find_symbol_by_offset(dest->sec, | |
187 | dest->offset); | |
188 | if (!dest_func) | |
189 | continue; | |
190 | ||
191 | if (recursion == 5) { | |
192 | WARN_FUNC("infinite recursion (objtool bug!)", | |
193 | dest->sec, dest->offset); | |
194 | return -1; | |
195 | } | |
196 | ||
197 | return __dead_end_function(file, dest_func, | |
198 | recursion + 1); | |
199 | } | |
200 | } | |
201 | ||
202 | if (insn->type == INSN_JUMP_DYNAMIC && list_empty(&insn->alts)) | |
203 | /* sibling call */ | |
204 | return 0; | |
205 | } | |
206 | ||
207 | return 1; | |
208 | } | |
209 | ||
210 | static int dead_end_function(struct objtool_file *file, struct symbol *func) | |
211 | { | |
212 | return __dead_end_function(file, func, 0); | |
213 | } | |
214 | ||
baa41469 JP |
215 | static void clear_insn_state(struct insn_state *state) |
216 | { | |
217 | int i; | |
218 | ||
219 | memset(state, 0, sizeof(*state)); | |
220 | state->cfa.base = CFI_UNDEFINED; | |
221 | for (i = 0; i < CFI_NUM_REGS; i++) | |
222 | state->regs[i].base = CFI_UNDEFINED; | |
223 | state->drap_reg = CFI_UNDEFINED; | |
224 | } | |
225 | ||
dcc914f4 JP |
226 | /* |
227 | * Call the arch-specific instruction decoder for all the instructions and add | |
228 | * them to the global instruction list. | |
229 | */ | |
230 | static int decode_instructions(struct objtool_file *file) | |
231 | { | |
232 | struct section *sec; | |
233 | struct symbol *func; | |
234 | unsigned long offset; | |
235 | struct instruction *insn; | |
236 | int ret; | |
237 | ||
baa41469 | 238 | for_each_sec(file, sec) { |
dcc914f4 JP |
239 | |
240 | if (!(sec->sh.sh_flags & SHF_EXECINSTR)) | |
241 | continue; | |
242 | ||
627fce14 JP |
243 | if (strcmp(sec->name, ".altinstr_replacement") && |
244 | strcmp(sec->name, ".altinstr_aux") && | |
245 | strncmp(sec->name, ".discard.", 9)) | |
246 | sec->text = true; | |
247 | ||
dcc914f4 JP |
248 | for (offset = 0; offset < sec->len; offset += insn->len) { |
249 | insn = malloc(sizeof(*insn)); | |
baa41469 JP |
250 | if (!insn) { |
251 | WARN("malloc failed"); | |
252 | return -1; | |
253 | } | |
dcc914f4 | 254 | memset(insn, 0, sizeof(*insn)); |
dcc914f4 | 255 | INIT_LIST_HEAD(&insn->alts); |
baa41469 JP |
256 | clear_insn_state(&insn->state); |
257 | ||
dcc914f4 JP |
258 | insn->sec = sec; |
259 | insn->offset = offset; | |
260 | ||
261 | ret = arch_decode_instruction(file->elf, sec, offset, | |
262 | sec->len - offset, | |
263 | &insn->len, &insn->type, | |
baa41469 JP |
264 | &insn->immediate, |
265 | &insn->stack_op); | |
dcc914f4 JP |
266 | if (ret) |
267 | return ret; | |
268 | ||
269 | if (!insn->type || insn->type > INSN_LAST) { | |
270 | WARN_FUNC("invalid instruction type %d", | |
271 | insn->sec, insn->offset, insn->type); | |
272 | return -1; | |
273 | } | |
274 | ||
275 | hash_add(file->insn_hash, &insn->hash, insn->offset); | |
276 | list_add_tail(&insn->list, &file->insn_list); | |
277 | } | |
278 | ||
279 | list_for_each_entry(func, &sec->symbol_list, list) { | |
280 | if (func->type != STT_FUNC) | |
281 | continue; | |
282 | ||
283 | if (!find_insn(file, sec, func->offset)) { | |
284 | WARN("%s(): can't find starting instruction", | |
285 | func->name); | |
286 | return -1; | |
287 | } | |
288 | ||
289 | func_for_each_insn(file, func, insn) | |
290 | if (!insn->func) | |
291 | insn->func = func; | |
292 | } | |
293 | } | |
294 | ||
295 | return 0; | |
296 | } | |
297 | ||
298 | /* | |
299 | * Find all uses of the unreachable() macro, which are code path dead ends. | |
300 | */ | |
301 | static int add_dead_ends(struct objtool_file *file) | |
302 | { | |
303 | struct section *sec; | |
304 | struct rela *rela; | |
305 | struct instruction *insn; | |
306 | bool found; | |
307 | ||
308 | sec = find_section_by_name(file->elf, ".rela.discard.unreachable"); | |
309 | if (!sec) | |
310 | return 0; | |
311 | ||
312 | list_for_each_entry(rela, &sec->rela_list, list) { | |
313 | if (rela->sym->type != STT_SECTION) { | |
314 | WARN("unexpected relocation symbol type in %s", sec->name); | |
315 | return -1; | |
316 | } | |
317 | insn = find_insn(file, rela->sym->sec, rela->addend); | |
318 | if (insn) | |
319 | insn = list_prev_entry(insn, list); | |
320 | else if (rela->addend == rela->sym->sec->len) { | |
321 | found = false; | |
322 | list_for_each_entry_reverse(insn, &file->insn_list, list) { | |
323 | if (insn->sec == rela->sym->sec) { | |
324 | found = true; | |
325 | break; | |
326 | } | |
327 | } | |
328 | ||
329 | if (!found) { | |
330 | WARN("can't find unreachable insn at %s+0x%x", | |
331 | rela->sym->sec->name, rela->addend); | |
332 | return -1; | |
333 | } | |
334 | } else { | |
335 | WARN("can't find unreachable insn at %s+0x%x", | |
336 | rela->sym->sec->name, rela->addend); | |
337 | return -1; | |
338 | } | |
339 | ||
340 | insn->dead_end = true; | |
341 | } | |
342 | ||
343 | return 0; | |
344 | } | |
345 | ||
346 | /* | |
347 | * Warnings shouldn't be reported for ignored functions. | |
348 | */ | |
349 | static void add_ignores(struct objtool_file *file) | |
350 | { | |
351 | struct instruction *insn; | |
352 | struct section *sec; | |
353 | struct symbol *func; | |
354 | ||
baa41469 | 355 | for_each_sec(file, sec) { |
dcc914f4 JP |
356 | list_for_each_entry(func, &sec->symbol_list, list) { |
357 | if (func->type != STT_FUNC) | |
358 | continue; | |
359 | ||
360 | if (!ignore_func(file, func)) | |
361 | continue; | |
362 | ||
363 | func_for_each_insn(file, func, insn) | |
baa41469 | 364 | insn->ignore = true; |
dcc914f4 JP |
365 | } |
366 | } | |
367 | } | |
368 | ||
369 | /* | |
370 | * Find the destination instructions for all jumps. | |
371 | */ | |
372 | static int add_jump_destinations(struct objtool_file *file) | |
373 | { | |
374 | struct instruction *insn; | |
375 | struct rela *rela; | |
376 | struct section *dest_sec; | |
377 | unsigned long dest_off; | |
378 | ||
379 | for_each_insn(file, insn) { | |
380 | if (insn->type != INSN_JUMP_CONDITIONAL && | |
381 | insn->type != INSN_JUMP_UNCONDITIONAL) | |
382 | continue; | |
383 | ||
baa41469 | 384 | if (insn->ignore) |
dcc914f4 JP |
385 | continue; |
386 | ||
387 | rela = find_rela_by_dest_range(insn->sec, insn->offset, | |
388 | insn->len); | |
389 | if (!rela) { | |
390 | dest_sec = insn->sec; | |
391 | dest_off = insn->offset + insn->len + insn->immediate; | |
392 | } else if (rela->sym->type == STT_SECTION) { | |
393 | dest_sec = rela->sym->sec; | |
394 | dest_off = rela->addend + 4; | |
395 | } else if (rela->sym->sec->idx) { | |
396 | dest_sec = rela->sym->sec; | |
397 | dest_off = rela->sym->sym.st_value + rela->addend + 4; | |
398 | } else { | |
399 | /* sibling call */ | |
400 | insn->jump_dest = 0; | |
401 | continue; | |
402 | } | |
403 | ||
404 | insn->jump_dest = find_insn(file, dest_sec, dest_off); | |
405 | if (!insn->jump_dest) { | |
406 | ||
407 | /* | |
408 | * This is a special case where an alt instruction | |
409 | * jumps past the end of the section. These are | |
410 | * handled later in handle_group_alt(). | |
411 | */ | |
412 | if (!strcmp(insn->sec->name, ".altinstr_replacement")) | |
413 | continue; | |
414 | ||
415 | WARN_FUNC("can't find jump dest instruction at %s+0x%lx", | |
416 | insn->sec, insn->offset, dest_sec->name, | |
417 | dest_off); | |
418 | return -1; | |
419 | } | |
420 | } | |
421 | ||
422 | return 0; | |
423 | } | |
424 | ||
425 | /* | |
426 | * Find the destination instructions for all calls. | |
427 | */ | |
428 | static int add_call_destinations(struct objtool_file *file) | |
429 | { | |
430 | struct instruction *insn; | |
431 | unsigned long dest_off; | |
432 | struct rela *rela; | |
433 | ||
434 | for_each_insn(file, insn) { | |
435 | if (insn->type != INSN_CALL) | |
436 | continue; | |
437 | ||
438 | rela = find_rela_by_dest_range(insn->sec, insn->offset, | |
439 | insn->len); | |
440 | if (!rela) { | |
441 | dest_off = insn->offset + insn->len + insn->immediate; | |
442 | insn->call_dest = find_symbol_by_offset(insn->sec, | |
443 | dest_off); | |
444 | if (!insn->call_dest) { | |
445 | WARN_FUNC("can't find call dest symbol at offset 0x%lx", | |
446 | insn->sec, insn->offset, dest_off); | |
447 | return -1; | |
448 | } | |
449 | } else if (rela->sym->type == STT_SECTION) { | |
450 | insn->call_dest = find_symbol_by_offset(rela->sym->sec, | |
451 | rela->addend+4); | |
452 | if (!insn->call_dest || | |
453 | insn->call_dest->type != STT_FUNC) { | |
454 | WARN_FUNC("can't find call dest symbol at %s+0x%x", | |
455 | insn->sec, insn->offset, | |
456 | rela->sym->sec->name, | |
457 | rela->addend + 4); | |
458 | return -1; | |
459 | } | |
460 | } else | |
461 | insn->call_dest = rela->sym; | |
462 | } | |
463 | ||
464 | return 0; | |
465 | } | |
466 | ||
467 | /* | |
468 | * The .alternatives section requires some extra special care, over and above | |
469 | * what other special sections require: | |
470 | * | |
471 | * 1. Because alternatives are patched in-place, we need to insert a fake jump | |
472 | * instruction at the end so that validate_branch() skips all the original | |
473 | * replaced instructions when validating the new instruction path. | |
474 | * | |
475 | * 2. An added wrinkle is that the new instruction length might be zero. In | |
476 | * that case the old instructions are replaced with noops. We simulate that | |
477 | * by creating a fake jump as the only new instruction. | |
478 | * | |
479 | * 3. In some cases, the alternative section includes an instruction which | |
480 | * conditionally jumps to the _end_ of the entry. We have to modify these | |
481 | * jumps' destinations to point back to .text rather than the end of the | |
482 | * entry in .altinstr_replacement. | |
483 | * | |
484 | * 4. It has been requested that we don't validate the !POPCNT feature path | |
485 | * which is a "very very small percentage of machines". | |
486 | */ | |
487 | static int handle_group_alt(struct objtool_file *file, | |
488 | struct special_alt *special_alt, | |
489 | struct instruction *orig_insn, | |
490 | struct instruction **new_insn) | |
491 | { | |
492 | struct instruction *last_orig_insn, *last_new_insn, *insn, *fake_jump; | |
493 | unsigned long dest_off; | |
494 | ||
495 | last_orig_insn = NULL; | |
496 | insn = orig_insn; | |
497 | sec_for_each_insn_from(file, insn) { | |
498 | if (insn->offset >= special_alt->orig_off + special_alt->orig_len) | |
499 | break; | |
500 | ||
501 | if (special_alt->skip_orig) | |
502 | insn->type = INSN_NOP; | |
503 | ||
504 | insn->alt_group = true; | |
505 | last_orig_insn = insn; | |
506 | } | |
507 | ||
508 | if (!next_insn_same_sec(file, last_orig_insn)) { | |
509 | WARN("%s: don't know how to handle alternatives at end of section", | |
510 | special_alt->orig_sec->name); | |
511 | return -1; | |
512 | } | |
513 | ||
514 | fake_jump = malloc(sizeof(*fake_jump)); | |
515 | if (!fake_jump) { | |
516 | WARN("malloc failed"); | |
517 | return -1; | |
518 | } | |
519 | memset(fake_jump, 0, sizeof(*fake_jump)); | |
520 | INIT_LIST_HEAD(&fake_jump->alts); | |
baa41469 JP |
521 | clear_insn_state(&fake_jump->state); |
522 | ||
dcc914f4 JP |
523 | fake_jump->sec = special_alt->new_sec; |
524 | fake_jump->offset = -1; | |
525 | fake_jump->type = INSN_JUMP_UNCONDITIONAL; | |
526 | fake_jump->jump_dest = list_next_entry(last_orig_insn, list); | |
baa41469 | 527 | fake_jump->ignore = true; |
dcc914f4 JP |
528 | |
529 | if (!special_alt->new_len) { | |
530 | *new_insn = fake_jump; | |
531 | return 0; | |
532 | } | |
533 | ||
534 | last_new_insn = NULL; | |
535 | insn = *new_insn; | |
536 | sec_for_each_insn_from(file, insn) { | |
537 | if (insn->offset >= special_alt->new_off + special_alt->new_len) | |
538 | break; | |
539 | ||
540 | last_new_insn = insn; | |
541 | ||
542 | if (insn->type != INSN_JUMP_CONDITIONAL && | |
543 | insn->type != INSN_JUMP_UNCONDITIONAL) | |
544 | continue; | |
545 | ||
546 | if (!insn->immediate) | |
547 | continue; | |
548 | ||
549 | dest_off = insn->offset + insn->len + insn->immediate; | |
550 | if (dest_off == special_alt->new_off + special_alt->new_len) | |
551 | insn->jump_dest = fake_jump; | |
552 | ||
553 | if (!insn->jump_dest) { | |
554 | WARN_FUNC("can't find alternative jump destination", | |
555 | insn->sec, insn->offset); | |
556 | return -1; | |
557 | } | |
558 | } | |
559 | ||
560 | if (!last_new_insn) { | |
561 | WARN_FUNC("can't find last new alternative instruction", | |
562 | special_alt->new_sec, special_alt->new_off); | |
563 | return -1; | |
564 | } | |
565 | ||
566 | list_add(&fake_jump->list, &last_new_insn->list); | |
567 | ||
568 | return 0; | |
569 | } | |
570 | ||
571 | /* | |
572 | * A jump table entry can either convert a nop to a jump or a jump to a nop. | |
573 | * If the original instruction is a jump, make the alt entry an effective nop | |
574 | * by just skipping the original instruction. | |
575 | */ | |
576 | static int handle_jump_alt(struct objtool_file *file, | |
577 | struct special_alt *special_alt, | |
578 | struct instruction *orig_insn, | |
579 | struct instruction **new_insn) | |
580 | { | |
581 | if (orig_insn->type == INSN_NOP) | |
582 | return 0; | |
583 | ||
584 | if (orig_insn->type != INSN_JUMP_UNCONDITIONAL) { | |
585 | WARN_FUNC("unsupported instruction at jump label", | |
586 | orig_insn->sec, orig_insn->offset); | |
587 | return -1; | |
588 | } | |
589 | ||
590 | *new_insn = list_next_entry(orig_insn, list); | |
591 | return 0; | |
592 | } | |
593 | ||
594 | /* | |
595 | * Read all the special sections which have alternate instructions which can be | |
596 | * patched in or redirected to at runtime. Each instruction having alternate | |
597 | * instruction(s) has them added to its insn->alts list, which will be | |
598 | * traversed in validate_branch(). | |
599 | */ | |
600 | static int add_special_section_alts(struct objtool_file *file) | |
601 | { | |
602 | struct list_head special_alts; | |
603 | struct instruction *orig_insn, *new_insn; | |
604 | struct special_alt *special_alt, *tmp; | |
605 | struct alternative *alt; | |
606 | int ret; | |
607 | ||
608 | ret = special_get_alts(file->elf, &special_alts); | |
609 | if (ret) | |
610 | return ret; | |
611 | ||
612 | list_for_each_entry_safe(special_alt, tmp, &special_alts, list) { | |
613 | alt = malloc(sizeof(*alt)); | |
614 | if (!alt) { | |
615 | WARN("malloc failed"); | |
616 | ret = -1; | |
617 | goto out; | |
618 | } | |
619 | ||
620 | orig_insn = find_insn(file, special_alt->orig_sec, | |
621 | special_alt->orig_off); | |
622 | if (!orig_insn) { | |
623 | WARN_FUNC("special: can't find orig instruction", | |
624 | special_alt->orig_sec, special_alt->orig_off); | |
625 | ret = -1; | |
626 | goto out; | |
627 | } | |
628 | ||
629 | new_insn = NULL; | |
630 | if (!special_alt->group || special_alt->new_len) { | |
631 | new_insn = find_insn(file, special_alt->new_sec, | |
632 | special_alt->new_off); | |
633 | if (!new_insn) { | |
634 | WARN_FUNC("special: can't find new instruction", | |
635 | special_alt->new_sec, | |
636 | special_alt->new_off); | |
637 | ret = -1; | |
638 | goto out; | |
639 | } | |
640 | } | |
641 | ||
642 | if (special_alt->group) { | |
643 | ret = handle_group_alt(file, special_alt, orig_insn, | |
644 | &new_insn); | |
645 | if (ret) | |
646 | goto out; | |
647 | } else if (special_alt->jump_or_nop) { | |
648 | ret = handle_jump_alt(file, special_alt, orig_insn, | |
649 | &new_insn); | |
650 | if (ret) | |
651 | goto out; | |
652 | } | |
653 | ||
654 | alt->insn = new_insn; | |
655 | list_add_tail(&alt->list, &orig_insn->alts); | |
656 | ||
657 | list_del(&special_alt->list); | |
658 | free(special_alt); | |
659 | } | |
660 | ||
661 | out: | |
662 | return ret; | |
663 | } | |
664 | ||
665 | static int add_switch_table(struct objtool_file *file, struct symbol *func, | |
666 | struct instruction *insn, struct rela *table, | |
667 | struct rela *next_table) | |
668 | { | |
669 | struct rela *rela = table; | |
670 | struct instruction *alt_insn; | |
671 | struct alternative *alt; | |
672 | ||
673 | list_for_each_entry_from(rela, &file->rodata->rela->rela_list, list) { | |
674 | if (rela == next_table) | |
675 | break; | |
676 | ||
677 | if (rela->sym->sec != insn->sec || | |
678 | rela->addend <= func->offset || | |
679 | rela->addend >= func->offset + func->len) | |
680 | break; | |
681 | ||
682 | alt_insn = find_insn(file, insn->sec, rela->addend); | |
683 | if (!alt_insn) { | |
684 | WARN("%s: can't find instruction at %s+0x%x", | |
685 | file->rodata->rela->name, insn->sec->name, | |
686 | rela->addend); | |
687 | return -1; | |
688 | } | |
689 | ||
690 | alt = malloc(sizeof(*alt)); | |
691 | if (!alt) { | |
692 | WARN("malloc failed"); | |
693 | return -1; | |
694 | } | |
695 | ||
696 | alt->insn = alt_insn; | |
697 | list_add_tail(&alt->list, &insn->alts); | |
698 | } | |
699 | ||
700 | return 0; | |
701 | } | |
702 | ||
703 | /* | |
704 | * find_switch_table() - Given a dynamic jump, find the switch jump table in | |
705 | * .rodata associated with it. | |
706 | * | |
707 | * There are 3 basic patterns: | |
708 | * | |
709 | * 1. jmpq *[rodata addr](,%reg,8) | |
710 | * | |
711 | * This is the most common case by far. It jumps to an address in a simple | |
712 | * jump table which is stored in .rodata. | |
713 | * | |
714 | * 2. jmpq *[rodata addr](%rip) | |
715 | * | |
716 | * This is caused by a rare GCC quirk, currently only seen in three driver | |
717 | * functions in the kernel, only with certain obscure non-distro configs. | |
718 | * | |
719 | * As part of an optimization, GCC makes a copy of an existing switch jump | |
720 | * table, modifies it, and then hard-codes the jump (albeit with an indirect | |
721 | * jump) to use a single entry in the table. The rest of the jump table and | |
722 | * some of its jump targets remain as dead code. | |
723 | * | |
724 | * In such a case we can just crudely ignore all unreachable instruction | |
725 | * warnings for the entire object file. Ideally we would just ignore them | |
726 | * for the function, but that would require redesigning the code quite a | |
727 | * bit. And honestly that's just not worth doing: unreachable instruction | |
728 | * warnings are of questionable value anyway, and this is such a rare issue. | |
729 | * | |
730 | * 3. mov [rodata addr],%reg1 | |
731 | * ... some instructions ... | |
732 | * jmpq *(%reg1,%reg2,8) | |
733 | * | |
734 | * This is a fairly uncommon pattern which is new for GCC 6. As of this | |
735 | * writing, there are 11 occurrences of it in the allmodconfig kernel. | |
736 | * | |
737 | * TODO: Once we have DWARF CFI and smarter instruction decoding logic, | |
738 | * ensure the same register is used in the mov and jump instructions. | |
739 | */ | |
740 | static struct rela *find_switch_table(struct objtool_file *file, | |
741 | struct symbol *func, | |
742 | struct instruction *insn) | |
743 | { | |
744 | struct rela *text_rela, *rodata_rela; | |
745 | struct instruction *orig_insn = insn; | |
746 | ||
747 | text_rela = find_rela_by_dest_range(insn->sec, insn->offset, insn->len); | |
748 | if (text_rela && text_rela->sym == file->rodata->sym) { | |
749 | /* case 1 */ | |
750 | rodata_rela = find_rela_by_dest(file->rodata, | |
751 | text_rela->addend); | |
752 | if (rodata_rela) | |
753 | return rodata_rela; | |
754 | ||
755 | /* case 2 */ | |
756 | rodata_rela = find_rela_by_dest(file->rodata, | |
757 | text_rela->addend + 4); | |
758 | if (!rodata_rela) | |
759 | return NULL; | |
760 | file->ignore_unreachables = true; | |
761 | return rodata_rela; | |
762 | } | |
763 | ||
764 | /* case 3 */ | |
765 | func_for_each_insn_continue_reverse(file, func, insn) { | |
766 | if (insn->type == INSN_JUMP_DYNAMIC) | |
767 | break; | |
768 | ||
769 | /* allow small jumps within the range */ | |
770 | if (insn->type == INSN_JUMP_UNCONDITIONAL && | |
771 | insn->jump_dest && | |
772 | (insn->jump_dest->offset <= insn->offset || | |
773 | insn->jump_dest->offset > orig_insn->offset)) | |
774 | break; | |
775 | ||
776 | /* look for a relocation which references .rodata */ | |
777 | text_rela = find_rela_by_dest_range(insn->sec, insn->offset, | |
778 | insn->len); | |
779 | if (!text_rela || text_rela->sym != file->rodata->sym) | |
780 | continue; | |
781 | ||
782 | /* | |
783 | * Make sure the .rodata address isn't associated with a | |
784 | * symbol. gcc jump tables are anonymous data. | |
785 | */ | |
786 | if (find_symbol_containing(file->rodata, text_rela->addend)) | |
787 | continue; | |
788 | ||
789 | return find_rela_by_dest(file->rodata, text_rela->addend); | |
790 | } | |
791 | ||
792 | return NULL; | |
793 | } | |
794 | ||
795 | static int add_func_switch_tables(struct objtool_file *file, | |
796 | struct symbol *func) | |
797 | { | |
798 | struct instruction *insn, *prev_jump = NULL; | |
799 | struct rela *rela, *prev_rela = NULL; | |
800 | int ret; | |
801 | ||
802 | func_for_each_insn(file, func, insn) { | |
803 | if (insn->type != INSN_JUMP_DYNAMIC) | |
804 | continue; | |
805 | ||
806 | rela = find_switch_table(file, func, insn); | |
807 | if (!rela) | |
808 | continue; | |
809 | ||
810 | /* | |
811 | * We found a switch table, but we don't know yet how big it | |
812 | * is. Don't add it until we reach the end of the function or | |
813 | * the beginning of another switch table in the same function. | |
814 | */ | |
815 | if (prev_jump) { | |
816 | ret = add_switch_table(file, func, prev_jump, prev_rela, | |
817 | rela); | |
818 | if (ret) | |
819 | return ret; | |
820 | } | |
821 | ||
822 | prev_jump = insn; | |
823 | prev_rela = rela; | |
824 | } | |
825 | ||
826 | if (prev_jump) { | |
827 | ret = add_switch_table(file, func, prev_jump, prev_rela, NULL); | |
828 | if (ret) | |
829 | return ret; | |
830 | } | |
831 | ||
832 | return 0; | |
833 | } | |
834 | ||
835 | /* | |
836 | * For some switch statements, gcc generates a jump table in the .rodata | |
837 | * section which contains a list of addresses within the function to jump to. | |
838 | * This finds these jump tables and adds them to the insn->alts lists. | |
839 | */ | |
840 | static int add_switch_table_alts(struct objtool_file *file) | |
841 | { | |
842 | struct section *sec; | |
843 | struct symbol *func; | |
844 | int ret; | |
845 | ||
846 | if (!file->rodata || !file->rodata->rela) | |
847 | return 0; | |
848 | ||
baa41469 | 849 | for_each_sec(file, sec) { |
dcc914f4 JP |
850 | list_for_each_entry(func, &sec->symbol_list, list) { |
851 | if (func->type != STT_FUNC) | |
852 | continue; | |
853 | ||
854 | ret = add_func_switch_tables(file, func); | |
855 | if (ret) | |
856 | return ret; | |
857 | } | |
858 | } | |
859 | ||
860 | return 0; | |
861 | } | |
862 | ||
39358a03 JP |
863 | static int read_unwind_hints(struct objtool_file *file) |
864 | { | |
865 | struct section *sec, *relasec; | |
866 | struct rela *rela; | |
867 | struct unwind_hint *hint; | |
868 | struct instruction *insn; | |
869 | struct cfi_reg *cfa; | |
870 | int i; | |
871 | ||
872 | sec = find_section_by_name(file->elf, ".discard.unwind_hints"); | |
873 | if (!sec) | |
874 | return 0; | |
875 | ||
876 | relasec = sec->rela; | |
877 | if (!relasec) { | |
878 | WARN("missing .rela.discard.unwind_hints section"); | |
879 | return -1; | |
880 | } | |
881 | ||
882 | if (sec->len % sizeof(struct unwind_hint)) { | |
883 | WARN("struct unwind_hint size mismatch"); | |
884 | return -1; | |
885 | } | |
886 | ||
887 | file->hints = true; | |
888 | ||
889 | for (i = 0; i < sec->len / sizeof(struct unwind_hint); i++) { | |
890 | hint = (struct unwind_hint *)sec->data->d_buf + i; | |
891 | ||
892 | rela = find_rela_by_dest(sec, i * sizeof(*hint)); | |
893 | if (!rela) { | |
894 | WARN("can't find rela for unwind_hints[%d]", i); | |
895 | return -1; | |
896 | } | |
897 | ||
898 | insn = find_insn(file, rela->sym->sec, rela->addend); | |
899 | if (!insn) { | |
900 | WARN("can't find insn for unwind_hints[%d]", i); | |
901 | return -1; | |
902 | } | |
903 | ||
904 | cfa = &insn->state.cfa; | |
905 | ||
906 | if (hint->type == UNWIND_HINT_TYPE_SAVE) { | |
907 | insn->save = true; | |
908 | continue; | |
909 | ||
910 | } else if (hint->type == UNWIND_HINT_TYPE_RESTORE) { | |
911 | insn->restore = true; | |
912 | insn->hint = true; | |
913 | continue; | |
914 | } | |
915 | ||
916 | insn->hint = true; | |
917 | ||
918 | switch (hint->sp_reg) { | |
919 | case ORC_REG_UNDEFINED: | |
920 | cfa->base = CFI_UNDEFINED; | |
921 | break; | |
922 | case ORC_REG_SP: | |
923 | cfa->base = CFI_SP; | |
924 | break; | |
925 | case ORC_REG_BP: | |
926 | cfa->base = CFI_BP; | |
927 | break; | |
928 | case ORC_REG_SP_INDIRECT: | |
929 | cfa->base = CFI_SP_INDIRECT; | |
930 | break; | |
931 | case ORC_REG_R10: | |
932 | cfa->base = CFI_R10; | |
933 | break; | |
934 | case ORC_REG_R13: | |
935 | cfa->base = CFI_R13; | |
936 | break; | |
937 | case ORC_REG_DI: | |
938 | cfa->base = CFI_DI; | |
939 | break; | |
940 | case ORC_REG_DX: | |
941 | cfa->base = CFI_DX; | |
942 | break; | |
943 | default: | |
944 | WARN_FUNC("unsupported unwind_hint sp base reg %d", | |
945 | insn->sec, insn->offset, hint->sp_reg); | |
946 | return -1; | |
947 | } | |
948 | ||
949 | cfa->offset = hint->sp_offset; | |
950 | insn->state.type = hint->type; | |
951 | } | |
952 | ||
953 | return 0; | |
954 | } | |
955 | ||
dcc914f4 JP |
956 | static int decode_sections(struct objtool_file *file) |
957 | { | |
958 | int ret; | |
959 | ||
960 | ret = decode_instructions(file); | |
961 | if (ret) | |
962 | return ret; | |
963 | ||
964 | ret = add_dead_ends(file); | |
965 | if (ret) | |
966 | return ret; | |
967 | ||
968 | add_ignores(file); | |
969 | ||
970 | ret = add_jump_destinations(file); | |
971 | if (ret) | |
972 | return ret; | |
973 | ||
974 | ret = add_call_destinations(file); | |
975 | if (ret) | |
976 | return ret; | |
977 | ||
978 | ret = add_special_section_alts(file); | |
979 | if (ret) | |
980 | return ret; | |
981 | ||
982 | ret = add_switch_table_alts(file); | |
983 | if (ret) | |
984 | return ret; | |
985 | ||
39358a03 JP |
986 | ret = read_unwind_hints(file); |
987 | if (ret) | |
988 | return ret; | |
989 | ||
dcc914f4 JP |
990 | return 0; |
991 | } | |
992 | ||
993 | static bool is_fentry_call(struct instruction *insn) | |
994 | { | |
995 | if (insn->type == INSN_CALL && | |
996 | insn->call_dest->type == STT_NOTYPE && | |
997 | !strcmp(insn->call_dest->name, "__fentry__")) | |
998 | return true; | |
999 | ||
1000 | return false; | |
1001 | } | |
1002 | ||
baa41469 | 1003 | static bool has_modified_stack_frame(struct insn_state *state) |
dcc914f4 | 1004 | { |
baa41469 JP |
1005 | int i; |
1006 | ||
1007 | if (state->cfa.base != initial_func_cfi.cfa.base || | |
1008 | state->cfa.offset != initial_func_cfi.cfa.offset || | |
1009 | state->stack_size != initial_func_cfi.cfa.offset || | |
1010 | state->drap) | |
1011 | return true; | |
1012 | ||
1013 | for (i = 0; i < CFI_NUM_REGS; i++) | |
1014 | if (state->regs[i].base != initial_func_cfi.regs[i].base || | |
1015 | state->regs[i].offset != initial_func_cfi.regs[i].offset) | |
1016 | return true; | |
1017 | ||
1018 | return false; | |
1019 | } | |
1020 | ||
1021 | static bool has_valid_stack_frame(struct insn_state *state) | |
1022 | { | |
1023 | if (state->cfa.base == CFI_BP && state->regs[CFI_BP].base == CFI_CFA && | |
1024 | state->regs[CFI_BP].offset == -16) | |
1025 | return true; | |
1026 | ||
1027 | if (state->drap && state->regs[CFI_BP].base == CFI_BP) | |
1028 | return true; | |
1029 | ||
1030 | return false; | |
dcc914f4 JP |
1031 | } |
1032 | ||
627fce14 JP |
1033 | static int update_insn_state_regs(struct instruction *insn, struct insn_state *state) |
1034 | { | |
1035 | struct cfi_reg *cfa = &state->cfa; | |
1036 | struct stack_op *op = &insn->stack_op; | |
1037 | ||
1038 | if (cfa->base != CFI_SP) | |
1039 | return 0; | |
1040 | ||
1041 | /* push */ | |
1042 | if (op->dest.type == OP_DEST_PUSH) | |
1043 | cfa->offset += 8; | |
1044 | ||
1045 | /* pop */ | |
1046 | if (op->src.type == OP_SRC_POP) | |
1047 | cfa->offset -= 8; | |
1048 | ||
1049 | /* add immediate to sp */ | |
1050 | if (op->dest.type == OP_DEST_REG && op->src.type == OP_SRC_ADD && | |
1051 | op->dest.reg == CFI_SP && op->src.reg == CFI_SP) | |
1052 | cfa->offset -= op->src.offset; | |
1053 | ||
1054 | return 0; | |
1055 | } | |
1056 | ||
baa41469 JP |
1057 | static void save_reg(struct insn_state *state, unsigned char reg, int base, |
1058 | int offset) | |
dcc914f4 | 1059 | { |
baa41469 JP |
1060 | if ((arch_callee_saved_reg(reg) || |
1061 | (state->drap && reg == state->drap_reg)) && | |
1062 | state->regs[reg].base == CFI_UNDEFINED) { | |
1063 | state->regs[reg].base = base; | |
1064 | state->regs[reg].offset = offset; | |
1065 | } | |
dcc914f4 JP |
1066 | } |
1067 | ||
baa41469 | 1068 | static void restore_reg(struct insn_state *state, unsigned char reg) |
dcc914f4 | 1069 | { |
baa41469 JP |
1070 | state->regs[reg].base = CFI_UNDEFINED; |
1071 | state->regs[reg].offset = 0; | |
1072 | } | |
1073 | ||
1074 | /* | |
1075 | * A note about DRAP stack alignment: | |
1076 | * | |
1077 | * GCC has the concept of a DRAP register, which is used to help keep track of | |
1078 | * the stack pointer when aligning the stack. r10 or r13 is used as the DRAP | |
1079 | * register. The typical DRAP pattern is: | |
1080 | * | |
1081 | * 4c 8d 54 24 08 lea 0x8(%rsp),%r10 | |
1082 | * 48 83 e4 c0 and $0xffffffffffffffc0,%rsp | |
1083 | * 41 ff 72 f8 pushq -0x8(%r10) | |
1084 | * 55 push %rbp | |
1085 | * 48 89 e5 mov %rsp,%rbp | |
1086 | * (more pushes) | |
1087 | * 41 52 push %r10 | |
1088 | * ... | |
1089 | * 41 5a pop %r10 | |
1090 | * (more pops) | |
1091 | * 5d pop %rbp | |
1092 | * 49 8d 62 f8 lea -0x8(%r10),%rsp | |
1093 | * c3 retq | |
1094 | * | |
1095 | * There are some variations in the epilogues, like: | |
1096 | * | |
1097 | * 5b pop %rbx | |
1098 | * 41 5a pop %r10 | |
1099 | * 41 5c pop %r12 | |
1100 | * 41 5d pop %r13 | |
1101 | * 41 5e pop %r14 | |
1102 | * c9 leaveq | |
1103 | * 49 8d 62 f8 lea -0x8(%r10),%rsp | |
1104 | * c3 retq | |
1105 | * | |
1106 | * and: | |
1107 | * | |
1108 | * 4c 8b 55 e8 mov -0x18(%rbp),%r10 | |
1109 | * 48 8b 5d e0 mov -0x20(%rbp),%rbx | |
1110 | * 4c 8b 65 f0 mov -0x10(%rbp),%r12 | |
1111 | * 4c 8b 6d f8 mov -0x8(%rbp),%r13 | |
1112 | * c9 leaveq | |
1113 | * 49 8d 62 f8 lea -0x8(%r10),%rsp | |
1114 | * c3 retq | |
1115 | * | |
1116 | * Sometimes r13 is used as the DRAP register, in which case it's saved and | |
1117 | * restored beforehand: | |
1118 | * | |
1119 | * 41 55 push %r13 | |
1120 | * 4c 8d 6c 24 10 lea 0x10(%rsp),%r13 | |
1121 | * 48 83 e4 f0 and $0xfffffffffffffff0,%rsp | |
1122 | * ... | |
1123 | * 49 8d 65 f0 lea -0x10(%r13),%rsp | |
1124 | * 41 5d pop %r13 | |
1125 | * c3 retq | |
1126 | */ | |
1127 | static int update_insn_state(struct instruction *insn, struct insn_state *state) | |
1128 | { | |
1129 | struct stack_op *op = &insn->stack_op; | |
1130 | struct cfi_reg *cfa = &state->cfa; | |
1131 | struct cfi_reg *regs = state->regs; | |
1132 | ||
1133 | /* stack operations don't make sense with an undefined CFA */ | |
1134 | if (cfa->base == CFI_UNDEFINED) { | |
1135 | if (insn->func) { | |
1136 | WARN_FUNC("undefined stack state", insn->sec, insn->offset); | |
1137 | return -1; | |
1138 | } | |
1139 | return 0; | |
1140 | } | |
1141 | ||
627fce14 JP |
1142 | if (state->type == ORC_TYPE_REGS || state->type == ORC_TYPE_REGS_IRET) |
1143 | return update_insn_state_regs(insn, state); | |
1144 | ||
baa41469 JP |
1145 | switch (op->dest.type) { |
1146 | ||
1147 | case OP_DEST_REG: | |
1148 | switch (op->src.type) { | |
1149 | ||
1150 | case OP_SRC_REG: | |
1151 | if (cfa->base == op->src.reg && cfa->base == CFI_SP && | |
1152 | op->dest.reg == CFI_BP && regs[CFI_BP].base == CFI_CFA && | |
1153 | regs[CFI_BP].offset == -cfa->offset) { | |
1154 | ||
1155 | /* mov %rsp, %rbp */ | |
1156 | cfa->base = op->dest.reg; | |
1157 | state->bp_scratch = false; | |
1158 | } else if (state->drap) { | |
1159 | ||
1160 | /* drap: mov %rsp, %rbp */ | |
1161 | regs[CFI_BP].base = CFI_BP; | |
1162 | regs[CFI_BP].offset = -state->stack_size; | |
1163 | state->bp_scratch = false; | |
867ac9d7 | 1164 | } else if (!no_fp) { |
baa41469 JP |
1165 | |
1166 | WARN_FUNC("unknown stack-related register move", | |
1167 | insn->sec, insn->offset); | |
1168 | return -1; | |
1169 | } | |
1170 | ||
1171 | break; | |
1172 | ||
1173 | case OP_SRC_ADD: | |
1174 | if (op->dest.reg == CFI_SP && op->src.reg == CFI_SP) { | |
1175 | ||
1176 | /* add imm, %rsp */ | |
1177 | state->stack_size -= op->src.offset; | |
1178 | if (cfa->base == CFI_SP) | |
1179 | cfa->offset -= op->src.offset; | |
1180 | break; | |
1181 | } | |
1182 | ||
1183 | if (op->dest.reg == CFI_SP && op->src.reg == CFI_BP) { | |
1184 | ||
1185 | /* lea disp(%rbp), %rsp */ | |
1186 | state->stack_size = -(op->src.offset + regs[CFI_BP].offset); | |
1187 | break; | |
1188 | } | |
1189 | ||
1190 | if (op->dest.reg != CFI_BP && op->src.reg == CFI_SP && | |
1191 | cfa->base == CFI_SP) { | |
1192 | ||
1193 | /* drap: lea disp(%rsp), %drap */ | |
1194 | state->drap_reg = op->dest.reg; | |
1195 | break; | |
1196 | } | |
1197 | ||
1198 | if (state->drap && op->dest.reg == CFI_SP && | |
1199 | op->src.reg == state->drap_reg) { | |
1200 | ||
1201 | /* drap: lea disp(%drap), %rsp */ | |
1202 | cfa->base = CFI_SP; | |
1203 | cfa->offset = state->stack_size = -op->src.offset; | |
1204 | state->drap_reg = CFI_UNDEFINED; | |
1205 | state->drap = false; | |
1206 | break; | |
1207 | } | |
1208 | ||
1209 | if (op->dest.reg == state->cfa.base) { | |
1210 | WARN_FUNC("unsupported stack register modification", | |
1211 | insn->sec, insn->offset); | |
1212 | return -1; | |
1213 | } | |
1214 | ||
1215 | break; | |
1216 | ||
1217 | case OP_SRC_AND: | |
1218 | if (op->dest.reg != CFI_SP || | |
1219 | (state->drap_reg != CFI_UNDEFINED && cfa->base != CFI_SP) || | |
1220 | (state->drap_reg == CFI_UNDEFINED && cfa->base != CFI_BP)) { | |
1221 | WARN_FUNC("unsupported stack pointer realignment", | |
1222 | insn->sec, insn->offset); | |
1223 | return -1; | |
1224 | } | |
1225 | ||
1226 | if (state->drap_reg != CFI_UNDEFINED) { | |
1227 | /* drap: and imm, %rsp */ | |
1228 | cfa->base = state->drap_reg; | |
1229 | cfa->offset = state->stack_size = 0; | |
1230 | state->drap = true; | |
1231 | ||
1232 | } | |
1233 | ||
1234 | /* | |
1235 | * Older versions of GCC (4.8ish) realign the stack | |
1236 | * without DRAP, with a frame pointer. | |
1237 | */ | |
1238 | ||
1239 | break; | |
1240 | ||
1241 | case OP_SRC_POP: | |
1242 | if (!state->drap && op->dest.type == OP_DEST_REG && | |
1243 | op->dest.reg == cfa->base) { | |
1244 | ||
1245 | /* pop %rbp */ | |
1246 | cfa->base = CFI_SP; | |
1247 | } | |
1248 | ||
1249 | if (regs[op->dest.reg].offset == -state->stack_size) { | |
1250 | ||
1251 | if (state->drap && cfa->base == CFI_BP_INDIRECT && | |
1252 | op->dest.type == OP_DEST_REG && | |
1253 | op->dest.reg == state->drap_reg) { | |
1254 | ||
1255 | /* drap: pop %drap */ | |
1256 | cfa->base = state->drap_reg; | |
1257 | cfa->offset = 0; | |
1258 | } | |
1259 | ||
1260 | restore_reg(state, op->dest.reg); | |
1261 | } | |
1262 | ||
1263 | state->stack_size -= 8; | |
1264 | if (cfa->base == CFI_SP) | |
1265 | cfa->offset -= 8; | |
1266 | ||
1267 | break; | |
1268 | ||
1269 | case OP_SRC_REG_INDIRECT: | |
1270 | if (state->drap && op->src.reg == CFI_BP && | |
1271 | op->src.offset == regs[op->dest.reg].offset) { | |
1272 | ||
1273 | /* drap: mov disp(%rbp), %reg */ | |
1274 | if (op->dest.reg == state->drap_reg) { | |
1275 | cfa->base = state->drap_reg; | |
1276 | cfa->offset = 0; | |
1277 | } | |
1278 | ||
1279 | restore_reg(state, op->dest.reg); | |
1280 | ||
1281 | } else if (op->src.reg == cfa->base && | |
1282 | op->src.offset == regs[op->dest.reg].offset + cfa->offset) { | |
1283 | ||
1284 | /* mov disp(%rbp), %reg */ | |
1285 | /* mov disp(%rsp), %reg */ | |
1286 | restore_reg(state, op->dest.reg); | |
1287 | } | |
1288 | ||
1289 | break; | |
1290 | ||
1291 | default: | |
1292 | WARN_FUNC("unknown stack-related instruction", | |
1293 | insn->sec, insn->offset); | |
1294 | return -1; | |
1295 | } | |
1296 | ||
1297 | break; | |
1298 | ||
1299 | case OP_DEST_PUSH: | |
1300 | state->stack_size += 8; | |
1301 | if (cfa->base == CFI_SP) | |
1302 | cfa->offset += 8; | |
1303 | ||
1304 | if (op->src.type != OP_SRC_REG) | |
1305 | break; | |
1306 | ||
1307 | if (state->drap) { | |
1308 | if (op->src.reg == cfa->base && op->src.reg == state->drap_reg) { | |
1309 | ||
1310 | /* drap: push %drap */ | |
1311 | cfa->base = CFI_BP_INDIRECT; | |
1312 | cfa->offset = -state->stack_size; | |
1313 | ||
1314 | /* save drap so we know when to undefine it */ | |
1315 | save_reg(state, op->src.reg, CFI_CFA, -state->stack_size); | |
1316 | ||
1317 | } else if (op->src.reg == CFI_BP && cfa->base == state->drap_reg) { | |
1318 | ||
1319 | /* drap: push %rbp */ | |
1320 | state->stack_size = 0; | |
1321 | ||
1322 | } else if (regs[op->src.reg].base == CFI_UNDEFINED) { | |
1323 | ||
1324 | /* drap: push %reg */ | |
1325 | save_reg(state, op->src.reg, CFI_BP, -state->stack_size); | |
1326 | } | |
1327 | ||
1328 | } else { | |
1329 | ||
1330 | /* push %reg */ | |
1331 | save_reg(state, op->src.reg, CFI_CFA, -state->stack_size); | |
1332 | } | |
1333 | ||
1334 | /* detect when asm code uses rbp as a scratch register */ | |
867ac9d7 | 1335 | if (!no_fp && insn->func && op->src.reg == CFI_BP && |
baa41469 JP |
1336 | cfa->base != CFI_BP) |
1337 | state->bp_scratch = true; | |
1338 | break; | |
1339 | ||
1340 | case OP_DEST_REG_INDIRECT: | |
1341 | ||
1342 | if (state->drap) { | |
1343 | if (op->src.reg == cfa->base && op->src.reg == state->drap_reg) { | |
1344 | ||
1345 | /* drap: mov %drap, disp(%rbp) */ | |
1346 | cfa->base = CFI_BP_INDIRECT; | |
1347 | cfa->offset = op->dest.offset; | |
1348 | ||
1349 | /* save drap so we know when to undefine it */ | |
1350 | save_reg(state, op->src.reg, CFI_CFA, op->dest.offset); | |
1351 | } | |
1352 | ||
1353 | else if (regs[op->src.reg].base == CFI_UNDEFINED) { | |
1354 | ||
1355 | /* drap: mov reg, disp(%rbp) */ | |
1356 | save_reg(state, op->src.reg, CFI_BP, op->dest.offset); | |
1357 | } | |
1358 | ||
1359 | } else if (op->dest.reg == cfa->base) { | |
1360 | ||
1361 | /* mov reg, disp(%rbp) */ | |
1362 | /* mov reg, disp(%rsp) */ | |
1363 | save_reg(state, op->src.reg, CFI_CFA, | |
1364 | op->dest.offset - state->cfa.offset); | |
1365 | } | |
1366 | ||
1367 | break; | |
1368 | ||
1369 | case OP_DEST_LEAVE: | |
1370 | if ((!state->drap && cfa->base != CFI_BP) || | |
1371 | (state->drap && cfa->base != state->drap_reg)) { | |
1372 | WARN_FUNC("leave instruction with modified stack frame", | |
1373 | insn->sec, insn->offset); | |
1374 | return -1; | |
1375 | } | |
1376 | ||
1377 | /* leave (mov %rbp, %rsp; pop %rbp) */ | |
1378 | ||
1379 | state->stack_size = -state->regs[CFI_BP].offset - 8; | |
1380 | restore_reg(state, CFI_BP); | |
1381 | ||
1382 | if (!state->drap) { | |
1383 | cfa->base = CFI_SP; | |
1384 | cfa->offset -= 8; | |
1385 | } | |
1386 | ||
1387 | break; | |
1388 | ||
1389 | case OP_DEST_MEM: | |
1390 | if (op->src.type != OP_SRC_POP) { | |
1391 | WARN_FUNC("unknown stack-related memory operation", | |
1392 | insn->sec, insn->offset); | |
1393 | return -1; | |
1394 | } | |
1395 | ||
1396 | /* pop mem */ | |
1397 | state->stack_size -= 8; | |
1398 | if (cfa->base == CFI_SP) | |
1399 | cfa->offset -= 8; | |
1400 | ||
1401 | break; | |
1402 | ||
1403 | default: | |
1404 | WARN_FUNC("unknown stack-related instruction", | |
1405 | insn->sec, insn->offset); | |
1406 | return -1; | |
1407 | } | |
1408 | ||
1409 | return 0; | |
1410 | } | |
1411 | ||
1412 | static bool insn_state_match(struct instruction *insn, struct insn_state *state) | |
1413 | { | |
1414 | struct insn_state *state1 = &insn->state, *state2 = state; | |
1415 | int i; | |
1416 | ||
1417 | if (memcmp(&state1->cfa, &state2->cfa, sizeof(state1->cfa))) { | |
1418 | WARN_FUNC("stack state mismatch: cfa1=%d%+d cfa2=%d%+d", | |
1419 | insn->sec, insn->offset, | |
1420 | state1->cfa.base, state1->cfa.offset, | |
1421 | state2->cfa.base, state2->cfa.offset); | |
1422 | ||
1423 | } else if (memcmp(&state1->regs, &state2->regs, sizeof(state1->regs))) { | |
1424 | for (i = 0; i < CFI_NUM_REGS; i++) { | |
1425 | if (!memcmp(&state1->regs[i], &state2->regs[i], | |
1426 | sizeof(struct cfi_reg))) | |
1427 | continue; | |
1428 | ||
1429 | WARN_FUNC("stack state mismatch: reg1[%d]=%d%+d reg2[%d]=%d%+d", | |
1430 | insn->sec, insn->offset, | |
1431 | i, state1->regs[i].base, state1->regs[i].offset, | |
1432 | i, state2->regs[i].base, state2->regs[i].offset); | |
1433 | break; | |
1434 | } | |
1435 | ||
627fce14 JP |
1436 | } else if (state1->type != state2->type) { |
1437 | WARN_FUNC("stack state mismatch: type1=%d type2=%d", | |
1438 | insn->sec, insn->offset, state1->type, state2->type); | |
1439 | ||
baa41469 JP |
1440 | } else if (state1->drap != state2->drap || |
1441 | (state1->drap && state1->drap_reg != state2->drap_reg)) { | |
1442 | WARN_FUNC("stack state mismatch: drap1=%d(%d) drap2=%d(%d)", | |
1443 | insn->sec, insn->offset, | |
1444 | state1->drap, state1->drap_reg, | |
1445 | state2->drap, state2->drap_reg); | |
1446 | ||
1447 | } else | |
1448 | return true; | |
1449 | ||
1450 | return false; | |
dcc914f4 JP |
1451 | } |
1452 | ||
1453 | /* | |
1454 | * Follow the branch starting at the given instruction, and recursively follow | |
1455 | * any other branches (jumps). Meanwhile, track the frame pointer state at | |
1456 | * each instruction and validate all the rules described in | |
1457 | * tools/objtool/Documentation/stack-validation.txt. | |
1458 | */ | |
baa41469 JP |
1459 | static int validate_branch(struct objtool_file *file, struct instruction *first, |
1460 | struct insn_state state) | |
dcc914f4 JP |
1461 | { |
1462 | struct alternative *alt; | |
39358a03 | 1463 | struct instruction *insn, *next_insn; |
dcc914f4 JP |
1464 | struct section *sec; |
1465 | struct symbol *func = NULL; | |
dcc914f4 JP |
1466 | int ret; |
1467 | ||
1468 | insn = first; | |
1469 | sec = insn->sec; | |
dcc914f4 JP |
1470 | |
1471 | if (insn->alt_group && list_empty(&insn->alts)) { | |
1472 | WARN_FUNC("don't know how to handle branch to middle of alternative instruction group", | |
1473 | sec, insn->offset); | |
baa41469 | 1474 | return -1; |
dcc914f4 JP |
1475 | } |
1476 | ||
1477 | while (1) { | |
39358a03 JP |
1478 | next_insn = next_insn_same_sec(file, insn); |
1479 | ||
dcc914f4 JP |
1480 | if (file->c_file && insn->func) { |
1481 | if (func && func != insn->func) { | |
1482 | WARN("%s() falls through to next function %s()", | |
1483 | func->name, insn->func->name); | |
1484 | return 1; | |
1485 | } | |
dcc914f4 JP |
1486 | } |
1487 | ||
baa41469 JP |
1488 | func = insn->func; |
1489 | ||
4855022a JP |
1490 | if (func && insn->ignore) { |
1491 | WARN_FUNC("BUG: why am I validating an ignored function?", | |
1492 | sec, insn->offset); | |
1493 | return -1; | |
1494 | } | |
1495 | ||
dcc914f4 | 1496 | if (insn->visited) { |
39358a03 | 1497 | if (!insn->hint && !insn_state_match(insn, &state)) |
dcc914f4 | 1498 | return 1; |
dcc914f4 JP |
1499 | |
1500 | return 0; | |
1501 | } | |
1502 | ||
39358a03 JP |
1503 | if (insn->hint) { |
1504 | if (insn->restore) { | |
1505 | struct instruction *save_insn, *i; | |
1506 | ||
1507 | i = insn; | |
1508 | save_insn = NULL; | |
1509 | func_for_each_insn_continue_reverse(file, func, i) { | |
1510 | if (i->save) { | |
1511 | save_insn = i; | |
1512 | break; | |
1513 | } | |
1514 | } | |
1515 | ||
1516 | if (!save_insn) { | |
1517 | WARN_FUNC("no corresponding CFI save for CFI restore", | |
1518 | sec, insn->offset); | |
1519 | return 1; | |
1520 | } | |
1521 | ||
1522 | if (!save_insn->visited) { | |
1523 | /* | |
1524 | * Oops, no state to copy yet. | |
1525 | * Hopefully we can reach this | |
1526 | * instruction from another branch | |
1527 | * after the save insn has been | |
1528 | * visited. | |
1529 | */ | |
1530 | if (insn == first) | |
1531 | return 0; | |
1532 | ||
1533 | WARN_FUNC("objtool isn't smart enough to handle this CFI save/restore combo", | |
1534 | sec, insn->offset); | |
1535 | return 1; | |
1536 | } | |
1537 | ||
1538 | insn->state = save_insn->state; | |
1539 | } | |
1540 | ||
1541 | state = insn->state; | |
1542 | ||
1543 | } else | |
1544 | insn->state = state; | |
dcc914f4 | 1545 | |
baa41469 JP |
1546 | insn->visited = true; |
1547 | ||
dcc914f4 JP |
1548 | list_for_each_entry(alt, &insn->alts, list) { |
1549 | ret = validate_branch(file, alt->insn, state); | |
1550 | if (ret) | |
1551 | return 1; | |
1552 | } | |
1553 | ||
1554 | switch (insn->type) { | |
1555 | ||
dcc914f4 | 1556 | case INSN_RETURN: |
baa41469 JP |
1557 | if (func && has_modified_stack_frame(&state)) { |
1558 | WARN_FUNC("return with modified stack frame", | |
dcc914f4 JP |
1559 | sec, insn->offset); |
1560 | return 1; | |
1561 | } | |
baa41469 JP |
1562 | |
1563 | if (state.bp_scratch) { | |
1564 | WARN("%s uses BP as a scratch register", | |
1565 | insn->func->name); | |
1566 | return 1; | |
1567 | } | |
1568 | ||
dcc914f4 JP |
1569 | return 0; |
1570 | ||
1571 | case INSN_CALL: | |
baa41469 | 1572 | if (is_fentry_call(insn)) |
dcc914f4 | 1573 | break; |
dcc914f4 JP |
1574 | |
1575 | ret = dead_end_function(file, insn->call_dest); | |
1576 | if (ret == 1) | |
1577 | return 0; | |
1578 | if (ret == -1) | |
1579 | return 1; | |
1580 | ||
1581 | /* fallthrough */ | |
1582 | case INSN_CALL_DYNAMIC: | |
867ac9d7 | 1583 | if (!no_fp && func && !has_valid_stack_frame(&state)) { |
dcc914f4 JP |
1584 | WARN_FUNC("call without frame pointer save/setup", |
1585 | sec, insn->offset); | |
1586 | return 1; | |
1587 | } | |
1588 | break; | |
1589 | ||
1590 | case INSN_JUMP_CONDITIONAL: | |
1591 | case INSN_JUMP_UNCONDITIONAL: | |
4855022a JP |
1592 | if (insn->jump_dest && |
1593 | (!func || !insn->jump_dest->func || | |
1594 | func == insn->jump_dest->func)) { | |
dcc914f4 JP |
1595 | ret = validate_branch(file, insn->jump_dest, |
1596 | state); | |
1597 | if (ret) | |
1598 | return 1; | |
4855022a | 1599 | |
baa41469 JP |
1600 | } else if (func && has_modified_stack_frame(&state)) { |
1601 | WARN_FUNC("sibling call from callable instruction with modified stack frame", | |
dcc914f4 JP |
1602 | sec, insn->offset); |
1603 | return 1; | |
4855022a | 1604 | } |
dcc914f4 JP |
1605 | |
1606 | if (insn->type == INSN_JUMP_UNCONDITIONAL) | |
1607 | return 0; | |
1608 | ||
1609 | break; | |
1610 | ||
1611 | case INSN_JUMP_DYNAMIC: | |
baa41469 JP |
1612 | if (func && list_empty(&insn->alts) && |
1613 | has_modified_stack_frame(&state)) { | |
1614 | WARN_FUNC("sibling call from callable instruction with modified stack frame", | |
dcc914f4 JP |
1615 | sec, insn->offset); |
1616 | return 1; | |
1617 | } | |
1618 | ||
1619 | return 0; | |
1620 | ||
39358a03 JP |
1621 | case INSN_CONTEXT_SWITCH: |
1622 | if (func && (!next_insn || !next_insn->hint)) { | |
1623 | WARN_FUNC("unsupported instruction in callable function", | |
1624 | sec, insn->offset); | |
1625 | return 1; | |
1626 | } | |
1627 | return 0; | |
1628 | ||
baa41469 JP |
1629 | case INSN_STACK: |
1630 | if (update_insn_state(insn, &state)) | |
1631 | return -1; | |
1632 | ||
1633 | break; | |
1634 | ||
dcc914f4 JP |
1635 | default: |
1636 | break; | |
1637 | } | |
1638 | ||
1639 | if (insn->dead_end) | |
1640 | return 0; | |
1641 | ||
39358a03 | 1642 | insn = next_insn; |
dcc914f4 JP |
1643 | if (!insn) { |
1644 | WARN("%s: unexpected end of section", sec->name); | |
1645 | return 1; | |
1646 | } | |
1647 | } | |
1648 | ||
1649 | return 0; | |
1650 | } | |
1651 | ||
39358a03 JP |
1652 | static int validate_unwind_hints(struct objtool_file *file) |
1653 | { | |
1654 | struct instruction *insn; | |
1655 | int ret, warnings = 0; | |
1656 | struct insn_state state; | |
1657 | ||
1658 | if (!file->hints) | |
1659 | return 0; | |
1660 | ||
1661 | clear_insn_state(&state); | |
1662 | ||
1663 | for_each_insn(file, insn) { | |
1664 | if (insn->hint && !insn->visited) { | |
1665 | ret = validate_branch(file, insn, state); | |
1666 | warnings += ret; | |
1667 | } | |
1668 | } | |
1669 | ||
1670 | return warnings; | |
1671 | } | |
1672 | ||
dcc914f4 JP |
1673 | static bool is_kasan_insn(struct instruction *insn) |
1674 | { | |
1675 | return (insn->type == INSN_CALL && | |
1676 | !strcmp(insn->call_dest->name, "__asan_handle_no_return")); | |
1677 | } | |
1678 | ||
1679 | static bool is_ubsan_insn(struct instruction *insn) | |
1680 | { | |
1681 | return (insn->type == INSN_CALL && | |
1682 | !strcmp(insn->call_dest->name, | |
1683 | "__ubsan_handle_builtin_unreachable")); | |
1684 | } | |
1685 | ||
baa41469 | 1686 | static bool ignore_unreachable_insn(struct instruction *insn) |
dcc914f4 JP |
1687 | { |
1688 | int i; | |
1689 | ||
baa41469 JP |
1690 | if (insn->ignore || insn->type == INSN_NOP) |
1691 | return true; | |
1692 | ||
1693 | /* | |
1694 | * Ignore any unused exceptions. This can happen when a whitelisted | |
1695 | * function has an exception table entry. | |
1696 | */ | |
1697 | if (!strcmp(insn->sec->name, ".fixup")) | |
dcc914f4 JP |
1698 | return true; |
1699 | ||
1700 | /* | |
1701 | * Check if this (or a subsequent) instruction is related to | |
1702 | * CONFIG_UBSAN or CONFIG_KASAN. | |
1703 | * | |
1704 | * End the search at 5 instructions to avoid going into the weeds. | |
1705 | */ | |
baa41469 JP |
1706 | if (!insn->func) |
1707 | return false; | |
dcc914f4 JP |
1708 | for (i = 0; i < 5; i++) { |
1709 | ||
1710 | if (is_kasan_insn(insn) || is_ubsan_insn(insn)) | |
1711 | return true; | |
1712 | ||
1713 | if (insn->type == INSN_JUMP_UNCONDITIONAL && insn->jump_dest) { | |
1714 | insn = insn->jump_dest; | |
1715 | continue; | |
1716 | } | |
1717 | ||
baa41469 | 1718 | if (insn->offset + insn->len >= insn->func->offset + insn->func->len) |
dcc914f4 JP |
1719 | break; |
1720 | insn = list_next_entry(insn, list); | |
1721 | } | |
1722 | ||
1723 | return false; | |
1724 | } | |
1725 | ||
1726 | static int validate_functions(struct objtool_file *file) | |
1727 | { | |
1728 | struct section *sec; | |
1729 | struct symbol *func; | |
1730 | struct instruction *insn; | |
baa41469 | 1731 | struct insn_state state; |
dcc914f4 JP |
1732 | int ret, warnings = 0; |
1733 | ||
baa41469 JP |
1734 | clear_insn_state(&state); |
1735 | ||
1736 | state.cfa = initial_func_cfi.cfa; | |
1737 | memcpy(&state.regs, &initial_func_cfi.regs, | |
1738 | CFI_NUM_REGS * sizeof(struct cfi_reg)); | |
1739 | state.stack_size = initial_func_cfi.cfa.offset; | |
1740 | ||
1741 | for_each_sec(file, sec) { | |
dcc914f4 JP |
1742 | list_for_each_entry(func, &sec->symbol_list, list) { |
1743 | if (func->type != STT_FUNC) | |
1744 | continue; | |
1745 | ||
1746 | insn = find_insn(file, sec, func->offset); | |
baa41469 | 1747 | if (!insn || insn->ignore) |
dcc914f4 JP |
1748 | continue; |
1749 | ||
baa41469 | 1750 | ret = validate_branch(file, insn, state); |
dcc914f4 JP |
1751 | warnings += ret; |
1752 | } | |
1753 | } | |
1754 | ||
dcc914f4 JP |
1755 | return warnings; |
1756 | } | |
1757 | ||
baa41469 | 1758 | static int validate_reachable_instructions(struct objtool_file *file) |
dcc914f4 JP |
1759 | { |
1760 | struct instruction *insn; | |
baa41469 JP |
1761 | |
1762 | if (file->ignore_unreachables) | |
1763 | return 0; | |
dcc914f4 JP |
1764 | |
1765 | for_each_insn(file, insn) { | |
baa41469 JP |
1766 | if (insn->visited || ignore_unreachable_insn(insn)) |
1767 | continue; | |
1768 | ||
baa41469 JP |
1769 | WARN_FUNC("unreachable instruction", insn->sec, insn->offset); |
1770 | return 1; | |
dcc914f4 JP |
1771 | } |
1772 | ||
baa41469 | 1773 | return 0; |
dcc914f4 JP |
1774 | } |
1775 | ||
1776 | static void cleanup(struct objtool_file *file) | |
1777 | { | |
1778 | struct instruction *insn, *tmpinsn; | |
1779 | struct alternative *alt, *tmpalt; | |
1780 | ||
1781 | list_for_each_entry_safe(insn, tmpinsn, &file->insn_list, list) { | |
1782 | list_for_each_entry_safe(alt, tmpalt, &insn->alts, list) { | |
1783 | list_del(&alt->list); | |
1784 | free(alt); | |
1785 | } | |
1786 | list_del(&insn->list); | |
1787 | hash_del(&insn->hash); | |
1788 | free(insn); | |
1789 | } | |
1790 | elf_close(file->elf); | |
1791 | } | |
1792 | ||
867ac9d7 | 1793 | int check(const char *_objname, bool _no_fp, bool no_unreachable, bool orc) |
dcc914f4 JP |
1794 | { |
1795 | struct objtool_file file; | |
1796 | int ret, warnings = 0; | |
1797 | ||
1798 | objname = _objname; | |
867ac9d7 | 1799 | no_fp = _no_fp; |
dcc914f4 | 1800 | |
627fce14 | 1801 | file.elf = elf_open(objname, orc ? O_RDWR : O_RDONLY); |
baa41469 | 1802 | if (!file.elf) |
dcc914f4 | 1803 | return 1; |
dcc914f4 JP |
1804 | |
1805 | INIT_LIST_HEAD(&file.insn_list); | |
1806 | hash_init(file.insn_hash); | |
1807 | file.whitelist = find_section_by_name(file.elf, ".discard.func_stack_frame_non_standard"); | |
1808 | file.rodata = find_section_by_name(file.elf, ".rodata"); | |
dcc914f4 | 1809 | file.c_file = find_section_by_name(file.elf, ".comment"); |
867ac9d7 | 1810 | file.ignore_unreachables = no_unreachable; |
39358a03 | 1811 | file.hints = false; |
dcc914f4 | 1812 | |
baa41469 JP |
1813 | arch_initial_func_cfi_state(&initial_func_cfi); |
1814 | ||
dcc914f4 JP |
1815 | ret = decode_sections(&file); |
1816 | if (ret < 0) | |
1817 | goto out; | |
1818 | warnings += ret; | |
1819 | ||
baa41469 | 1820 | if (list_empty(&file.insn_list)) |
dcc914f4 | 1821 | goto out; |
dcc914f4 | 1822 | |
baa41469 | 1823 | ret = validate_functions(&file); |
dcc914f4 JP |
1824 | if (ret < 0) |
1825 | goto out; | |
1826 | warnings += ret; | |
1827 | ||
39358a03 JP |
1828 | ret = validate_unwind_hints(&file); |
1829 | if (ret < 0) | |
1830 | goto out; | |
1831 | warnings += ret; | |
1832 | ||
baa41469 JP |
1833 | if (!warnings) { |
1834 | ret = validate_reachable_instructions(&file); | |
1835 | if (ret < 0) | |
1836 | goto out; | |
1837 | warnings += ret; | |
1838 | } | |
1839 | ||
627fce14 JP |
1840 | if (orc) { |
1841 | ret = create_orc(&file); | |
1842 | if (ret < 0) | |
1843 | goto out; | |
1844 | ||
1845 | ret = create_orc_sections(&file); | |
1846 | if (ret < 0) | |
1847 | goto out; | |
1848 | ||
1849 | ret = elf_write(file.elf); | |
1850 | if (ret < 0) | |
1851 | goto out; | |
1852 | } | |
1853 | ||
dcc914f4 JP |
1854 | out: |
1855 | cleanup(&file); | |
1856 | ||
1857 | /* ignore warnings for now until we get all the code cleaned up */ | |
1858 | if (ret || warnings) | |
1859 | return 0; | |
1860 | return 0; | |
1861 | } |