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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 | /* | |
19 | * objtool check: | |
20 | * | |
21 | * This command analyzes every .o file and ensures the validity of its stack | |
22 | * trace metadata. It enforces a set of rules on asm code and C inline | |
23 | * assembly code so that stack traces can be reliable. | |
24 | * | |
25 | * For more information, see tools/objtool/Documentation/stack-validation.txt. | |
26 | */ | |
27 | ||
28 | #include <string.h> | |
d0761e37 | 29 | #include <stdlib.h> |
442f04c3 JP |
30 | #include <subcmd/parse-options.h> |
31 | ||
32 | #include "builtin.h" | |
33 | #include "elf.h" | |
34 | #include "special.h" | |
35 | #include "arch.h" | |
36 | #include "warn.h" | |
37 | ||
042ba73f JP |
38 | #include <linux/hashtable.h> |
39 | ||
442f04c3 JP |
40 | #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) |
41 | ||
42 | #define STATE_FP_SAVED 0x1 | |
43 | #define STATE_FP_SETUP 0x2 | |
44 | #define STATE_FENTRY 0x4 | |
45 | ||
46 | struct instruction { | |
47 | struct list_head list; | |
042ba73f | 48 | struct hlist_node hash; |
442f04c3 JP |
49 | struct section *sec; |
50 | unsigned long offset; | |
51 | unsigned int len, state; | |
52 | unsigned char type; | |
53 | unsigned long immediate; | |
54 | bool alt_group, visited; | |
55 | struct symbol *call_dest; | |
56 | struct instruction *jump_dest; | |
57 | struct list_head alts; | |
b1547d31 | 58 | struct symbol *func; |
442f04c3 JP |
59 | }; |
60 | ||
61 | struct alternative { | |
62 | struct list_head list; | |
63 | struct instruction *insn; | |
64 | }; | |
65 | ||
66 | struct objtool_file { | |
67 | struct elf *elf; | |
a196e171 | 68 | struct list_head insn_list; |
042ba73f JP |
69 | DECLARE_HASHTABLE(insn_hash, 16); |
70 | struct section *rodata, *whitelist; | |
b1547d31 | 71 | bool ignore_unreachables, c_file; |
442f04c3 JP |
72 | }; |
73 | ||
74 | const char *objname; | |
75 | static bool nofp; | |
76 | ||
74aec058 JP |
77 | static struct instruction *find_insn(struct objtool_file *file, |
78 | struct section *sec, unsigned long offset) | |
442f04c3 JP |
79 | { |
80 | struct instruction *insn; | |
81 | ||
042ba73f | 82 | hash_for_each_possible(file->insn_hash, insn, hash, offset) |
442f04c3 JP |
83 | if (insn->sec == sec && insn->offset == offset) |
84 | return insn; | |
85 | ||
86 | return NULL; | |
87 | } | |
88 | ||
74aec058 JP |
89 | static struct instruction *next_insn_same_sec(struct objtool_file *file, |
90 | struct instruction *insn) | |
91 | { | |
92 | struct instruction *next = list_next_entry(insn, list); | |
93 | ||
a196e171 | 94 | if (&next->list == &file->insn_list || next->sec != insn->sec) |
74aec058 JP |
95 | return NULL; |
96 | ||
97 | return next; | |
98 | } | |
99 | ||
9cfffb11 JP |
100 | static bool gcov_enabled(struct objtool_file *file) |
101 | { | |
102 | struct section *sec; | |
103 | struct symbol *sym; | |
104 | ||
105 | list_for_each_entry(sec, &file->elf->sections, list) | |
106 | list_for_each_entry(sym, &sec->symbol_list, list) | |
107 | if (!strncmp(sym->name, "__gcov_.", 8)) | |
108 | return true; | |
109 | ||
110 | return false; | |
111 | } | |
112 | ||
74aec058 | 113 | #define for_each_insn(file, insn) \ |
a196e171 | 114 | list_for_each_entry(insn, &file->insn_list, list) |
74aec058 JP |
115 | |
116 | #define func_for_each_insn(file, func, insn) \ | |
117 | for (insn = find_insn(file, func->sec, func->offset); \ | |
a196e171 | 118 | insn && &insn->list != &file->insn_list && \ |
74aec058 JP |
119 | insn->sec == func->sec && \ |
120 | insn->offset < func->offset + func->len; \ | |
121 | insn = list_next_entry(insn, list)) | |
122 | ||
6d01f28b JP |
123 | #define func_for_each_insn_continue_reverse(file, func, insn) \ |
124 | for (insn = list_prev_entry(insn, list); \ | |
125 | &insn->list != &file->insn_list && \ | |
126 | insn->sec == func->sec && insn->offset >= func->offset; \ | |
127 | insn = list_prev_entry(insn, list)) | |
128 | ||
74aec058 JP |
129 | #define sec_for_each_insn_from(file, insn) \ |
130 | for (; insn; insn = next_insn_same_sec(file, insn)) | |
131 | ||
132 | ||
442f04c3 JP |
133 | /* |
134 | * Check if the function has been manually whitelisted with the | |
135 | * STACK_FRAME_NON_STANDARD macro, or if it should be automatically whitelisted | |
136 | * due to its use of a context switching instruction. | |
137 | */ | |
138 | static bool ignore_func(struct objtool_file *file, struct symbol *func) | |
139 | { | |
442f04c3 JP |
140 | struct rela *rela; |
141 | struct instruction *insn; | |
142 | ||
143 | /* check for STACK_FRAME_NON_STANDARD */ | |
042ba73f | 144 | if (file->whitelist && file->whitelist->rela) |
0ea5ad86 JP |
145 | list_for_each_entry(rela, &file->whitelist->rela->rela_list, list) { |
146 | if (rela->sym->type == STT_SECTION && | |
147 | rela->sym->sec == func->sec && | |
442f04c3 JP |
148 | rela->addend == func->offset) |
149 | return true; | |
0ea5ad86 JP |
150 | if (rela->sym->type == STT_FUNC && rela->sym == func) |
151 | return true; | |
152 | } | |
442f04c3 JP |
153 | |
154 | /* check if it has a context switching instruction */ | |
74aec058 | 155 | func_for_each_insn(file, func, insn) |
442f04c3 JP |
156 | if (insn->type == INSN_CONTEXT_SWITCH) |
157 | return true; | |
442f04c3 JP |
158 | |
159 | return false; | |
160 | } | |
161 | ||
162 | /* | |
163 | * This checks to see if the given function is a "noreturn" function. | |
164 | * | |
165 | * For global functions which are outside the scope of this object file, we | |
166 | * have to keep a manual list of them. | |
167 | * | |
168 | * For local functions, we have to detect them manually by simply looking for | |
169 | * the lack of a return instruction. | |
b1e03249 JP |
170 | * |
171 | * Returns: | |
172 | * -1: error | |
173 | * 0: no dead end | |
174 | * 1: dead end | |
442f04c3 | 175 | */ |
b1e03249 JP |
176 | static int __dead_end_function(struct objtool_file *file, struct symbol *func, |
177 | int recursion) | |
442f04c3 JP |
178 | { |
179 | int i; | |
74aec058 | 180 | struct instruction *insn; |
442f04c3 JP |
181 | bool empty = true; |
182 | ||
183 | /* | |
184 | * Unfortunately these have to be hard coded because the noreturn | |
185 | * attribute isn't provided in ELF data. | |
186 | */ | |
187 | static const char * const global_noreturns[] = { | |
188 | "__stack_chk_fail", | |
189 | "panic", | |
190 | "do_exit", | |
c1fad9ef | 191 | "do_task_dead", |
442f04c3 JP |
192 | "__module_put_and_exit", |
193 | "complete_and_exit", | |
194 | "kvm_spurious_fault", | |
195 | "__reiserfs_panic", | |
196 | "lbug_with_loc" | |
197 | }; | |
198 | ||
199 | if (func->bind == STB_WEAK) | |
b1e03249 | 200 | return 0; |
442f04c3 JP |
201 | |
202 | if (func->bind == STB_GLOBAL) | |
203 | for (i = 0; i < ARRAY_SIZE(global_noreturns); i++) | |
204 | if (!strcmp(func->name, global_noreturns[i])) | |
b1e03249 | 205 | return 1; |
442f04c3 JP |
206 | |
207 | if (!func->sec) | |
b1e03249 | 208 | return 0; |
442f04c3 | 209 | |
74aec058 | 210 | func_for_each_insn(file, func, insn) { |
442f04c3 JP |
211 | empty = false; |
212 | ||
213 | if (insn->type == INSN_RETURN) | |
b1e03249 | 214 | return 0; |
81bfafca JP |
215 | } |
216 | ||
217 | if (empty) | |
b1e03249 | 218 | return 0; |
81bfafca JP |
219 | |
220 | /* | |
221 | * A function can have a sibling call instead of a return. In that | |
222 | * case, the function's dead-end status depends on whether the target | |
223 | * of the sibling call returns. | |
224 | */ | |
74aec058 | 225 | func_for_each_insn(file, func, insn) { |
81bfafca JP |
226 | if (insn->sec != func->sec || |
227 | insn->offset >= func->offset + func->len) | |
228 | break; | |
442f04c3 JP |
229 | |
230 | if (insn->type == INSN_JUMP_UNCONDITIONAL) { | |
231 | struct instruction *dest = insn->jump_dest; | |
232 | struct symbol *dest_func; | |
233 | ||
234 | if (!dest) | |
235 | /* sibling call to another file */ | |
b1e03249 | 236 | return 0; |
442f04c3 JP |
237 | |
238 | if (dest->sec != func->sec || | |
239 | dest->offset < func->offset || | |
240 | dest->offset >= func->offset + func->len) { | |
241 | /* local sibling call */ | |
242 | dest_func = find_symbol_by_offset(dest->sec, | |
243 | dest->offset); | |
244 | if (!dest_func) | |
245 | continue; | |
246 | ||
b1e03249 JP |
247 | if (recursion == 5) { |
248 | WARN_FUNC("infinite recursion (objtool bug!)", | |
249 | dest->sec, dest->offset); | |
250 | return -1; | |
251 | } | |
252 | ||
253 | return __dead_end_function(file, dest_func, | |
254 | recursion + 1); | |
442f04c3 JP |
255 | } |
256 | } | |
257 | ||
b1547d31 | 258 | if (insn->type == INSN_JUMP_DYNAMIC && list_empty(&insn->alts)) |
442f04c3 | 259 | /* sibling call */ |
b1e03249 | 260 | return 0; |
442f04c3 JP |
261 | } |
262 | ||
b1e03249 JP |
263 | return 1; |
264 | } | |
265 | ||
266 | static int dead_end_function(struct objtool_file *file, struct symbol *func) | |
267 | { | |
268 | return __dead_end_function(file, func, 0); | |
442f04c3 JP |
269 | } |
270 | ||
271 | /* | |
272 | * Call the arch-specific instruction decoder for all the instructions and add | |
a196e171 | 273 | * them to the global instruction list. |
442f04c3 JP |
274 | */ |
275 | static int decode_instructions(struct objtool_file *file) | |
276 | { | |
277 | struct section *sec; | |
b1547d31 | 278 | struct symbol *func; |
442f04c3 JP |
279 | unsigned long offset; |
280 | struct instruction *insn; | |
281 | int ret; | |
282 | ||
442f04c3 JP |
283 | list_for_each_entry(sec, &file->elf->sections, list) { |
284 | ||
285 | if (!(sec->sh.sh_flags & SHF_EXECINSTR)) | |
286 | continue; | |
287 | ||
288 | for (offset = 0; offset < sec->len; offset += insn->len) { | |
289 | insn = malloc(sizeof(*insn)); | |
290 | memset(insn, 0, sizeof(*insn)); | |
291 | ||
292 | INIT_LIST_HEAD(&insn->alts); | |
293 | insn->sec = sec; | |
294 | insn->offset = offset; | |
295 | ||
296 | ret = arch_decode_instruction(file->elf, sec, offset, | |
297 | sec->len - offset, | |
298 | &insn->len, &insn->type, | |
299 | &insn->immediate); | |
300 | if (ret) | |
301 | return ret; | |
302 | ||
303 | if (!insn->type || insn->type > INSN_LAST) { | |
304 | WARN_FUNC("invalid instruction type %d", | |
305 | insn->sec, insn->offset, insn->type); | |
306 | return -1; | |
307 | } | |
308 | ||
042ba73f | 309 | hash_add(file->insn_hash, &insn->hash, insn->offset); |
a196e171 | 310 | list_add_tail(&insn->list, &file->insn_list); |
442f04c3 | 311 | } |
b1547d31 JP |
312 | |
313 | list_for_each_entry(func, &sec->symbol_list, list) { | |
314 | if (func->type != STT_FUNC) | |
315 | continue; | |
316 | ||
317 | if (!find_insn(file, sec, func->offset)) { | |
318 | WARN("%s(): can't find starting instruction", | |
319 | func->name); | |
320 | return -1; | |
321 | } | |
322 | ||
323 | func_for_each_insn(file, func, insn) | |
324 | if (!insn->func) | |
325 | insn->func = func; | |
326 | } | |
442f04c3 JP |
327 | } |
328 | ||
329 | return 0; | |
330 | } | |
331 | ||
332 | /* | |
333 | * Warnings shouldn't be reported for ignored functions. | |
334 | */ | |
a196e171 | 335 | static void add_ignores(struct objtool_file *file) |
442f04c3 JP |
336 | { |
337 | struct instruction *insn; | |
338 | struct section *sec; | |
339 | struct symbol *func; | |
340 | ||
341 | list_for_each_entry(sec, &file->elf->sections, list) { | |
a196e171 | 342 | list_for_each_entry(func, &sec->symbol_list, list) { |
442f04c3 JP |
343 | if (func->type != STT_FUNC) |
344 | continue; | |
345 | ||
346 | if (!ignore_func(file, func)) | |
347 | continue; | |
348 | ||
74aec058 | 349 | func_for_each_insn(file, func, insn) |
442f04c3 | 350 | insn->visited = true; |
442f04c3 JP |
351 | } |
352 | } | |
353 | } | |
354 | ||
355 | /* | |
356 | * Find the destination instructions for all jumps. | |
357 | */ | |
a196e171 | 358 | static int add_jump_destinations(struct objtool_file *file) |
442f04c3 JP |
359 | { |
360 | struct instruction *insn; | |
361 | struct rela *rela; | |
362 | struct section *dest_sec; | |
363 | unsigned long dest_off; | |
364 | ||
74aec058 | 365 | for_each_insn(file, insn) { |
442f04c3 JP |
366 | if (insn->type != INSN_JUMP_CONDITIONAL && |
367 | insn->type != INSN_JUMP_UNCONDITIONAL) | |
368 | continue; | |
369 | ||
370 | /* skip ignores */ | |
371 | if (insn->visited) | |
372 | continue; | |
373 | ||
374 | rela = find_rela_by_dest_range(insn->sec, insn->offset, | |
375 | insn->len); | |
376 | if (!rela) { | |
377 | dest_sec = insn->sec; | |
378 | dest_off = insn->offset + insn->len + insn->immediate; | |
379 | } else if (rela->sym->type == STT_SECTION) { | |
380 | dest_sec = rela->sym->sec; | |
381 | dest_off = rela->addend + 4; | |
382 | } else if (rela->sym->sec->idx) { | |
383 | dest_sec = rela->sym->sec; | |
384 | dest_off = rela->sym->sym.st_value + rela->addend + 4; | |
385 | } else { | |
386 | /* sibling call */ | |
387 | insn->jump_dest = 0; | |
388 | continue; | |
389 | } | |
390 | ||
74aec058 | 391 | insn->jump_dest = find_insn(file, dest_sec, dest_off); |
442f04c3 JP |
392 | if (!insn->jump_dest) { |
393 | ||
394 | /* | |
395 | * This is a special case where an alt instruction | |
396 | * jumps past the end of the section. These are | |
397 | * handled later in handle_group_alt(). | |
398 | */ | |
399 | if (!strcmp(insn->sec->name, ".altinstr_replacement")) | |
400 | continue; | |
401 | ||
402 | WARN_FUNC("can't find jump dest instruction at %s+0x%lx", | |
403 | insn->sec, insn->offset, dest_sec->name, | |
404 | dest_off); | |
405 | return -1; | |
406 | } | |
407 | } | |
408 | ||
409 | return 0; | |
410 | } | |
411 | ||
412 | /* | |
413 | * Find the destination instructions for all calls. | |
414 | */ | |
a196e171 | 415 | static int add_call_destinations(struct objtool_file *file) |
442f04c3 JP |
416 | { |
417 | struct instruction *insn; | |
418 | unsigned long dest_off; | |
419 | struct rela *rela; | |
420 | ||
74aec058 | 421 | for_each_insn(file, insn) { |
442f04c3 JP |
422 | if (insn->type != INSN_CALL) |
423 | continue; | |
424 | ||
425 | rela = find_rela_by_dest_range(insn->sec, insn->offset, | |
426 | insn->len); | |
427 | if (!rela) { | |
428 | dest_off = insn->offset + insn->len + insn->immediate; | |
429 | insn->call_dest = find_symbol_by_offset(insn->sec, | |
430 | dest_off); | |
431 | if (!insn->call_dest) { | |
432 | WARN_FUNC("can't find call dest symbol at offset 0x%lx", | |
433 | insn->sec, insn->offset, dest_off); | |
434 | return -1; | |
435 | } | |
436 | } else if (rela->sym->type == STT_SECTION) { | |
437 | insn->call_dest = find_symbol_by_offset(rela->sym->sec, | |
438 | rela->addend+4); | |
439 | if (!insn->call_dest || | |
440 | insn->call_dest->type != STT_FUNC) { | |
441 | WARN_FUNC("can't find call dest symbol at %s+0x%x", | |
442 | insn->sec, insn->offset, | |
443 | rela->sym->sec->name, | |
444 | rela->addend + 4); | |
445 | return -1; | |
446 | } | |
447 | } else | |
448 | insn->call_dest = rela->sym; | |
449 | } | |
450 | ||
451 | return 0; | |
452 | } | |
453 | ||
454 | /* | |
455 | * The .alternatives section requires some extra special care, over and above | |
456 | * what other special sections require: | |
457 | * | |
458 | * 1. Because alternatives are patched in-place, we need to insert a fake jump | |
459 | * instruction at the end so that validate_branch() skips all the original | |
460 | * replaced instructions when validating the new instruction path. | |
461 | * | |
462 | * 2. An added wrinkle is that the new instruction length might be zero. In | |
463 | * that case the old instructions are replaced with noops. We simulate that | |
464 | * by creating a fake jump as the only new instruction. | |
465 | * | |
466 | * 3. In some cases, the alternative section includes an instruction which | |
467 | * conditionally jumps to the _end_ of the entry. We have to modify these | |
468 | * jumps' destinations to point back to .text rather than the end of the | |
469 | * entry in .altinstr_replacement. | |
470 | * | |
471 | * 4. It has been requested that we don't validate the !POPCNT feature path | |
472 | * which is a "very very small percentage of machines". | |
473 | */ | |
474 | static int handle_group_alt(struct objtool_file *file, | |
475 | struct special_alt *special_alt, | |
476 | struct instruction *orig_insn, | |
477 | struct instruction **new_insn) | |
478 | { | |
479 | struct instruction *last_orig_insn, *last_new_insn, *insn, *fake_jump; | |
480 | unsigned long dest_off; | |
481 | ||
482 | last_orig_insn = NULL; | |
483 | insn = orig_insn; | |
74aec058 JP |
484 | sec_for_each_insn_from(file, insn) { |
485 | if (insn->offset >= special_alt->orig_off + special_alt->orig_len) | |
442f04c3 JP |
486 | break; |
487 | ||
488 | if (special_alt->skip_orig) | |
489 | insn->type = INSN_NOP; | |
490 | ||
491 | insn->alt_group = true; | |
492 | last_orig_insn = insn; | |
493 | } | |
494 | ||
74aec058 | 495 | if (!next_insn_same_sec(file, last_orig_insn)) { |
442f04c3 JP |
496 | WARN("%s: don't know how to handle alternatives at end of section", |
497 | special_alt->orig_sec->name); | |
498 | return -1; | |
499 | } | |
500 | ||
501 | fake_jump = malloc(sizeof(*fake_jump)); | |
502 | if (!fake_jump) { | |
503 | WARN("malloc failed"); | |
504 | return -1; | |
505 | } | |
506 | memset(fake_jump, 0, sizeof(*fake_jump)); | |
507 | INIT_LIST_HEAD(&fake_jump->alts); | |
508 | fake_jump->sec = special_alt->new_sec; | |
509 | fake_jump->offset = -1; | |
510 | fake_jump->type = INSN_JUMP_UNCONDITIONAL; | |
511 | fake_jump->jump_dest = list_next_entry(last_orig_insn, list); | |
512 | ||
513 | if (!special_alt->new_len) { | |
514 | *new_insn = fake_jump; | |
515 | return 0; | |
516 | } | |
517 | ||
518 | last_new_insn = NULL; | |
519 | insn = *new_insn; | |
74aec058 JP |
520 | sec_for_each_insn_from(file, insn) { |
521 | if (insn->offset >= special_alt->new_off + special_alt->new_len) | |
442f04c3 JP |
522 | break; |
523 | ||
524 | last_new_insn = insn; | |
525 | ||
526 | if (insn->type != INSN_JUMP_CONDITIONAL && | |
527 | insn->type != INSN_JUMP_UNCONDITIONAL) | |
528 | continue; | |
529 | ||
530 | if (!insn->immediate) | |
531 | continue; | |
532 | ||
533 | dest_off = insn->offset + insn->len + insn->immediate; | |
534 | if (dest_off == special_alt->new_off + special_alt->new_len) | |
535 | insn->jump_dest = fake_jump; | |
536 | ||
537 | if (!insn->jump_dest) { | |
538 | WARN_FUNC("can't find alternative jump destination", | |
539 | insn->sec, insn->offset); | |
540 | return -1; | |
541 | } | |
542 | } | |
543 | ||
544 | if (!last_new_insn) { | |
545 | WARN_FUNC("can't find last new alternative instruction", | |
546 | special_alt->new_sec, special_alt->new_off); | |
547 | return -1; | |
548 | } | |
549 | ||
550 | list_add(&fake_jump->list, &last_new_insn->list); | |
551 | ||
552 | return 0; | |
553 | } | |
554 | ||
555 | /* | |
556 | * A jump table entry can either convert a nop to a jump or a jump to a nop. | |
557 | * If the original instruction is a jump, make the alt entry an effective nop | |
558 | * by just skipping the original instruction. | |
559 | */ | |
560 | static int handle_jump_alt(struct objtool_file *file, | |
561 | struct special_alt *special_alt, | |
562 | struct instruction *orig_insn, | |
563 | struct instruction **new_insn) | |
564 | { | |
565 | if (orig_insn->type == INSN_NOP) | |
566 | return 0; | |
567 | ||
568 | if (orig_insn->type != INSN_JUMP_UNCONDITIONAL) { | |
569 | WARN_FUNC("unsupported instruction at jump label", | |
570 | orig_insn->sec, orig_insn->offset); | |
571 | return -1; | |
572 | } | |
573 | ||
574 | *new_insn = list_next_entry(orig_insn, list); | |
575 | return 0; | |
576 | } | |
577 | ||
578 | /* | |
579 | * Read all the special sections which have alternate instructions which can be | |
580 | * patched in or redirected to at runtime. Each instruction having alternate | |
581 | * instruction(s) has them added to its insn->alts list, which will be | |
582 | * traversed in validate_branch(). | |
583 | */ | |
a196e171 | 584 | static int add_special_section_alts(struct objtool_file *file) |
442f04c3 JP |
585 | { |
586 | struct list_head special_alts; | |
587 | struct instruction *orig_insn, *new_insn; | |
588 | struct special_alt *special_alt, *tmp; | |
589 | struct alternative *alt; | |
590 | int ret; | |
591 | ||
592 | ret = special_get_alts(file->elf, &special_alts); | |
593 | if (ret) | |
594 | return ret; | |
595 | ||
596 | list_for_each_entry_safe(special_alt, tmp, &special_alts, list) { | |
597 | alt = malloc(sizeof(*alt)); | |
598 | if (!alt) { | |
599 | WARN("malloc failed"); | |
600 | ret = -1; | |
601 | goto out; | |
602 | } | |
603 | ||
74aec058 JP |
604 | orig_insn = find_insn(file, special_alt->orig_sec, |
605 | special_alt->orig_off); | |
442f04c3 JP |
606 | if (!orig_insn) { |
607 | WARN_FUNC("special: can't find orig instruction", | |
608 | special_alt->orig_sec, special_alt->orig_off); | |
609 | ret = -1; | |
610 | goto out; | |
611 | } | |
612 | ||
613 | new_insn = NULL; | |
614 | if (!special_alt->group || special_alt->new_len) { | |
74aec058 JP |
615 | new_insn = find_insn(file, special_alt->new_sec, |
616 | special_alt->new_off); | |
442f04c3 JP |
617 | if (!new_insn) { |
618 | WARN_FUNC("special: can't find new instruction", | |
619 | special_alt->new_sec, | |
620 | special_alt->new_off); | |
621 | ret = -1; | |
622 | goto out; | |
623 | } | |
624 | } | |
625 | ||
626 | if (special_alt->group) { | |
627 | ret = handle_group_alt(file, special_alt, orig_insn, | |
628 | &new_insn); | |
629 | if (ret) | |
630 | goto out; | |
631 | } else if (special_alt->jump_or_nop) { | |
632 | ret = handle_jump_alt(file, special_alt, orig_insn, | |
633 | &new_insn); | |
634 | if (ret) | |
635 | goto out; | |
636 | } | |
637 | ||
638 | alt->insn = new_insn; | |
639 | list_add_tail(&alt->list, &orig_insn->alts); | |
640 | ||
641 | list_del(&special_alt->list); | |
642 | free(special_alt); | |
643 | } | |
644 | ||
645 | out: | |
646 | return ret; | |
647 | } | |
648 | ||
8133fbb4 JP |
649 | static int add_switch_table(struct objtool_file *file, struct symbol *func, |
650 | struct instruction *insn, struct rela *table, | |
651 | struct rela *next_table) | |
442f04c3 | 652 | { |
8133fbb4 JP |
653 | struct rela *rela = table; |
654 | struct instruction *alt_insn; | |
442f04c3 JP |
655 | struct alternative *alt; |
656 | ||
8133fbb4 JP |
657 | list_for_each_entry_from(rela, &file->rodata->rela->rela_list, list) { |
658 | if (rela == next_table) | |
659 | break; | |
660 | ||
661 | if (rela->sym->sec != insn->sec || | |
662 | rela->addend <= func->offset || | |
663 | rela->addend >= func->offset + func->len) | |
664 | break; | |
665 | ||
666 | alt_insn = find_insn(file, insn->sec, rela->addend); | |
667 | if (!alt_insn) { | |
668 | WARN("%s: can't find instruction at %s+0x%x", | |
669 | file->rodata->rela->name, insn->sec->name, | |
670 | rela->addend); | |
671 | return -1; | |
672 | } | |
673 | ||
674 | alt = malloc(sizeof(*alt)); | |
675 | if (!alt) { | |
676 | WARN("malloc failed"); | |
677 | return -1; | |
678 | } | |
679 | ||
680 | alt->insn = alt_insn; | |
681 | list_add_tail(&alt->list, &insn->alts); | |
682 | } | |
683 | ||
684 | return 0; | |
685 | } | |
686 | ||
6d01f28b JP |
687 | /* |
688 | * find_switch_table() - Given a dynamic jump, find the switch jump table in | |
689 | * .rodata associated with it. | |
690 | * | |
691 | * There are 3 basic patterns: | |
692 | * | |
693 | * 1. jmpq *[rodata addr](,%reg,8) | |
694 | * | |
695 | * This is the most common case by far. It jumps to an address in a simple | |
696 | * jump table which is stored in .rodata. | |
697 | * | |
698 | * 2. jmpq *[rodata addr](%rip) | |
699 | * | |
700 | * This is caused by a rare GCC quirk, currently only seen in three driver | |
701 | * functions in the kernel, only with certain obscure non-distro configs. | |
702 | * | |
703 | * As part of an optimization, GCC makes a copy of an existing switch jump | |
704 | * table, modifies it, and then hard-codes the jump (albeit with an indirect | |
705 | * jump) to use a single entry in the table. The rest of the jump table and | |
706 | * some of its jump targets remain as dead code. | |
707 | * | |
708 | * In such a case we can just crudely ignore all unreachable instruction | |
709 | * warnings for the entire object file. Ideally we would just ignore them | |
710 | * for the function, but that would require redesigning the code quite a | |
711 | * bit. And honestly that's just not worth doing: unreachable instruction | |
712 | * warnings are of questionable value anyway, and this is such a rare issue. | |
713 | * | |
714 | * 3. mov [rodata addr],%reg1 | |
715 | * ... some instructions ... | |
716 | * jmpq *(%reg1,%reg2,8) | |
717 | * | |
718 | * This is a fairly uncommon pattern which is new for GCC 6. As of this | |
719 | * writing, there are 11 occurrences of it in the allmodconfig kernel. | |
720 | * | |
721 | * TODO: Once we have DWARF CFI and smarter instruction decoding logic, | |
722 | * ensure the same register is used in the mov and jump instructions. | |
723 | */ | |
724 | static struct rela *find_switch_table(struct objtool_file *file, | |
725 | struct symbol *func, | |
726 | struct instruction *insn) | |
8133fbb4 | 727 | { |
6d01f28b | 728 | struct rela *text_rela, *rodata_rela; |
3732710f | 729 | struct instruction *orig_insn = insn; |
8133fbb4 | 730 | |
6d01f28b JP |
731 | text_rela = find_rela_by_dest_range(insn->sec, insn->offset, insn->len); |
732 | if (text_rela && text_rela->sym == file->rodata->sym) { | |
733 | /* case 1 */ | |
734 | rodata_rela = find_rela_by_dest(file->rodata, | |
735 | text_rela->addend); | |
736 | if (rodata_rela) | |
737 | return rodata_rela; | |
8133fbb4 | 738 | |
6d01f28b JP |
739 | /* case 2 */ |
740 | rodata_rela = find_rela_by_dest(file->rodata, | |
741 | text_rela->addend + 4); | |
742 | if (!rodata_rela) | |
743 | return NULL; | |
744 | file->ignore_unreachables = true; | |
745 | return rodata_rela; | |
746 | } | |
747 | ||
748 | /* case 3 */ | |
749 | func_for_each_insn_continue_reverse(file, func, insn) { | |
3732710f | 750 | if (insn->type == INSN_JUMP_DYNAMIC) |
6d01f28b | 751 | break; |
442f04c3 | 752 | |
3732710f JP |
753 | /* allow small jumps within the range */ |
754 | if (insn->type == INSN_JUMP_UNCONDITIONAL && | |
755 | insn->jump_dest && | |
756 | (insn->jump_dest->offset <= insn->offset || | |
757 | insn->jump_dest->offset >= orig_insn->offset)) | |
758 | break; | |
759 | ||
a196e171 JP |
760 | text_rela = find_rela_by_dest_range(insn->sec, insn->offset, |
761 | insn->len); | |
6d01f28b JP |
762 | if (text_rela && text_rela->sym == file->rodata->sym) |
763 | return find_rela_by_dest(file->rodata, | |
764 | text_rela->addend); | |
765 | } | |
442f04c3 | 766 | |
6d01f28b JP |
767 | return NULL; |
768 | } | |
8133fbb4 | 769 | |
6d01f28b JP |
770 | static int add_func_switch_tables(struct objtool_file *file, |
771 | struct symbol *func) | |
772 | { | |
773 | struct instruction *insn, *prev_jump = NULL; | |
774 | struct rela *rela, *prev_rela = NULL; | |
775 | int ret; | |
8133fbb4 | 776 | |
6d01f28b JP |
777 | func_for_each_insn(file, func, insn) { |
778 | if (insn->type != INSN_JUMP_DYNAMIC) | |
779 | continue; | |
780 | ||
781 | rela = find_switch_table(file, func, insn); | |
782 | if (!rela) | |
442f04c3 JP |
783 | continue; |
784 | ||
8133fbb4 JP |
785 | /* |
786 | * We found a switch table, but we don't know yet how big it | |
787 | * is. Don't add it until we reach the end of the function or | |
788 | * the beginning of another switch table in the same function. | |
789 | */ | |
790 | if (prev_jump) { | |
791 | ret = add_switch_table(file, func, prev_jump, prev_rela, | |
6d01f28b | 792 | rela); |
8133fbb4 JP |
793 | if (ret) |
794 | return ret; | |
442f04c3 JP |
795 | } |
796 | ||
8133fbb4 | 797 | prev_jump = insn; |
6d01f28b | 798 | prev_rela = rela; |
8133fbb4 | 799 | } |
442f04c3 | 800 | |
8133fbb4 JP |
801 | if (prev_jump) { |
802 | ret = add_switch_table(file, func, prev_jump, prev_rela, NULL); | |
803 | if (ret) | |
804 | return ret; | |
805 | } | |
806 | ||
807 | return 0; | |
808 | } | |
442f04c3 | 809 | |
8133fbb4 JP |
810 | /* |
811 | * For some switch statements, gcc generates a jump table in the .rodata | |
812 | * section which contains a list of addresses within the function to jump to. | |
813 | * This finds these jump tables and adds them to the insn->alts lists. | |
814 | */ | |
815 | static int add_switch_table_alts(struct objtool_file *file) | |
816 | { | |
817 | struct section *sec; | |
818 | struct symbol *func; | |
819 | int ret; | |
820 | ||
821 | if (!file->rodata || !file->rodata->rela) | |
822 | return 0; | |
823 | ||
824 | list_for_each_entry(sec, &file->elf->sections, list) { | |
825 | list_for_each_entry(func, &sec->symbol_list, list) { | |
826 | if (func->type != STT_FUNC) | |
827 | continue; | |
828 | ||
829 | ret = add_func_switch_tables(file, func); | |
830 | if (ret) | |
831 | return ret; | |
442f04c3 JP |
832 | } |
833 | } | |
834 | ||
835 | return 0; | |
836 | } | |
837 | ||
838 | static int decode_sections(struct objtool_file *file) | |
839 | { | |
840 | int ret; | |
841 | ||
842 | ret = decode_instructions(file); | |
843 | if (ret) | |
844 | return ret; | |
845 | ||
a196e171 | 846 | add_ignores(file); |
442f04c3 | 847 | |
a196e171 | 848 | ret = add_jump_destinations(file); |
442f04c3 JP |
849 | if (ret) |
850 | return ret; | |
851 | ||
a196e171 | 852 | ret = add_call_destinations(file); |
442f04c3 JP |
853 | if (ret) |
854 | return ret; | |
855 | ||
a196e171 | 856 | ret = add_special_section_alts(file); |
442f04c3 JP |
857 | if (ret) |
858 | return ret; | |
859 | ||
a196e171 | 860 | ret = add_switch_table_alts(file); |
442f04c3 JP |
861 | if (ret) |
862 | return ret; | |
863 | ||
864 | return 0; | |
865 | } | |
866 | ||
867 | static bool is_fentry_call(struct instruction *insn) | |
868 | { | |
869 | if (insn->type == INSN_CALL && | |
870 | insn->call_dest->type == STT_NOTYPE && | |
871 | !strcmp(insn->call_dest->name, "__fentry__")) | |
872 | return true; | |
873 | ||
874 | return false; | |
875 | } | |
876 | ||
877 | static bool has_modified_stack_frame(struct instruction *insn) | |
878 | { | |
879 | return (insn->state & STATE_FP_SAVED) || | |
880 | (insn->state & STATE_FP_SETUP); | |
881 | } | |
882 | ||
883 | static bool has_valid_stack_frame(struct instruction *insn) | |
884 | { | |
885 | return (insn->state & STATE_FP_SAVED) && | |
886 | (insn->state & STATE_FP_SETUP); | |
887 | } | |
888 | ||
d8d1b2cb JP |
889 | static unsigned int frame_state(unsigned long state) |
890 | { | |
891 | return (state & (STATE_FP_SAVED | STATE_FP_SETUP)); | |
892 | } | |
893 | ||
442f04c3 JP |
894 | /* |
895 | * Follow the branch starting at the given instruction, and recursively follow | |
896 | * any other branches (jumps). Meanwhile, track the frame pointer state at | |
897 | * each instruction and validate all the rules described in | |
898 | * tools/objtool/Documentation/stack-validation.txt. | |
899 | */ | |
900 | static int validate_branch(struct objtool_file *file, | |
901 | struct instruction *first, unsigned char first_state) | |
902 | { | |
903 | struct alternative *alt; | |
904 | struct instruction *insn; | |
905 | struct section *sec; | |
b1547d31 | 906 | struct symbol *func = NULL; |
442f04c3 | 907 | unsigned char state; |
1bcb58a0 | 908 | int ret; |
442f04c3 JP |
909 | |
910 | insn = first; | |
911 | sec = insn->sec; | |
912 | state = first_state; | |
913 | ||
914 | if (insn->alt_group && list_empty(&insn->alts)) { | |
915 | WARN_FUNC("don't know how to handle branch to middle of alternative instruction group", | |
916 | sec, insn->offset); | |
1bcb58a0 | 917 | return 1; |
442f04c3 JP |
918 | } |
919 | ||
920 | while (1) { | |
b1547d31 JP |
921 | if (file->c_file && insn->func) { |
922 | if (func && func != insn->func) { | |
923 | WARN("%s() falls through to next function %s()", | |
924 | func->name, insn->func->name); | |
925 | return 1; | |
926 | } | |
927 | ||
928 | func = insn->func; | |
929 | } | |
930 | ||
442f04c3 | 931 | if (insn->visited) { |
d8d1b2cb | 932 | if (frame_state(insn->state) != frame_state(state)) { |
442f04c3 JP |
933 | WARN_FUNC("frame pointer state mismatch", |
934 | sec, insn->offset); | |
1bcb58a0 | 935 | return 1; |
442f04c3 JP |
936 | } |
937 | ||
1bcb58a0 | 938 | return 0; |
442f04c3 JP |
939 | } |
940 | ||
442f04c3 JP |
941 | insn->visited = true; |
942 | insn->state = state; | |
943 | ||
944 | list_for_each_entry(alt, &insn->alts, list) { | |
945 | ret = validate_branch(file, alt->insn, state); | |
1bcb58a0 JP |
946 | if (ret) |
947 | return 1; | |
442f04c3 JP |
948 | } |
949 | ||
950 | switch (insn->type) { | |
951 | ||
952 | case INSN_FP_SAVE: | |
953 | if (!nofp) { | |
954 | if (state & STATE_FP_SAVED) { | |
955 | WARN_FUNC("duplicate frame pointer save", | |
956 | sec, insn->offset); | |
1bcb58a0 | 957 | return 1; |
442f04c3 JP |
958 | } |
959 | state |= STATE_FP_SAVED; | |
960 | } | |
961 | break; | |
962 | ||
963 | case INSN_FP_SETUP: | |
964 | if (!nofp) { | |
965 | if (state & STATE_FP_SETUP) { | |
966 | WARN_FUNC("duplicate frame pointer setup", | |
967 | sec, insn->offset); | |
1bcb58a0 | 968 | return 1; |
442f04c3 JP |
969 | } |
970 | state |= STATE_FP_SETUP; | |
971 | } | |
972 | break; | |
973 | ||
974 | case INSN_FP_RESTORE: | |
975 | if (!nofp) { | |
976 | if (has_valid_stack_frame(insn)) | |
977 | state &= ~STATE_FP_SETUP; | |
978 | ||
979 | state &= ~STATE_FP_SAVED; | |
980 | } | |
981 | break; | |
982 | ||
983 | case INSN_RETURN: | |
984 | if (!nofp && has_modified_stack_frame(insn)) { | |
985 | WARN_FUNC("return without frame pointer restore", | |
986 | sec, insn->offset); | |
1bcb58a0 | 987 | return 1; |
442f04c3 | 988 | } |
1bcb58a0 | 989 | return 0; |
442f04c3 JP |
990 | |
991 | case INSN_CALL: | |
992 | if (is_fentry_call(insn)) { | |
993 | state |= STATE_FENTRY; | |
994 | break; | |
995 | } | |
996 | ||
b1e03249 JP |
997 | ret = dead_end_function(file, insn->call_dest); |
998 | if (ret == 1) | |
1bcb58a0 | 999 | return 0; |
b1e03249 | 1000 | if (ret == -1) |
1bcb58a0 | 1001 | return 1; |
442f04c3 JP |
1002 | |
1003 | /* fallthrough */ | |
1004 | case INSN_CALL_DYNAMIC: | |
1005 | if (!nofp && !has_valid_stack_frame(insn)) { | |
1006 | WARN_FUNC("call without frame pointer save/setup", | |
1007 | sec, insn->offset); | |
1bcb58a0 | 1008 | return 1; |
442f04c3 JP |
1009 | } |
1010 | break; | |
1011 | ||
1012 | case INSN_JUMP_CONDITIONAL: | |
1013 | case INSN_JUMP_UNCONDITIONAL: | |
1014 | if (insn->jump_dest) { | |
1015 | ret = validate_branch(file, insn->jump_dest, | |
1016 | state); | |
1bcb58a0 JP |
1017 | if (ret) |
1018 | return 1; | |
442f04c3 JP |
1019 | } else if (has_modified_stack_frame(insn)) { |
1020 | WARN_FUNC("sibling call from callable instruction with changed frame pointer", | |
1021 | sec, insn->offset); | |
1bcb58a0 | 1022 | return 1; |
442f04c3 JP |
1023 | } /* else it's a sibling call */ |
1024 | ||
1025 | if (insn->type == INSN_JUMP_UNCONDITIONAL) | |
1bcb58a0 | 1026 | return 0; |
442f04c3 JP |
1027 | |
1028 | break; | |
1029 | ||
1030 | case INSN_JUMP_DYNAMIC: | |
1031 | if (list_empty(&insn->alts) && | |
1032 | has_modified_stack_frame(insn)) { | |
1033 | WARN_FUNC("sibling call from callable instruction with changed frame pointer", | |
1034 | sec, insn->offset); | |
1bcb58a0 | 1035 | return 1; |
442f04c3 JP |
1036 | } |
1037 | ||
1bcb58a0 | 1038 | return 0; |
442f04c3 JP |
1039 | |
1040 | case INSN_BUG: | |
1bcb58a0 | 1041 | return 0; |
442f04c3 JP |
1042 | |
1043 | default: | |
1044 | break; | |
1045 | } | |
1046 | ||
74aec058 JP |
1047 | insn = next_insn_same_sec(file, insn); |
1048 | if (!insn) { | |
442f04c3 | 1049 | WARN("%s: unexpected end of section", sec->name); |
1bcb58a0 | 1050 | return 1; |
442f04c3 JP |
1051 | } |
1052 | } | |
1053 | ||
1bcb58a0 | 1054 | return 0; |
442f04c3 JP |
1055 | } |
1056 | ||
442f04c3 JP |
1057 | static bool is_kasan_insn(struct instruction *insn) |
1058 | { | |
1059 | return (insn->type == INSN_CALL && | |
1060 | !strcmp(insn->call_dest->name, "__asan_handle_no_return")); | |
1061 | } | |
1062 | ||
1063 | static bool is_ubsan_insn(struct instruction *insn) | |
1064 | { | |
1065 | return (insn->type == INSN_CALL && | |
1066 | !strcmp(insn->call_dest->name, | |
1067 | "__ubsan_handle_builtin_unreachable")); | |
1068 | } | |
1069 | ||
74aec058 JP |
1070 | static bool ignore_unreachable_insn(struct symbol *func, |
1071 | struct instruction *insn) | |
442f04c3 JP |
1072 | { |
1073 | int i; | |
1074 | ||
1075 | if (insn->type == INSN_NOP) | |
1076 | return true; | |
1077 | ||
442f04c3 JP |
1078 | /* |
1079 | * Check if this (or a subsequent) instruction is related to | |
1080 | * CONFIG_UBSAN or CONFIG_KASAN. | |
1081 | * | |
1082 | * End the search at 5 instructions to avoid going into the weeds. | |
1083 | */ | |
1084 | for (i = 0; i < 5; i++) { | |
1085 | ||
1086 | if (is_kasan_insn(insn) || is_ubsan_insn(insn)) | |
1087 | return true; | |
1088 | ||
1089 | if (insn->type == INSN_JUMP_UNCONDITIONAL && insn->jump_dest) { | |
1090 | insn = insn->jump_dest; | |
1091 | continue; | |
1092 | } | |
1093 | ||
74aec058 | 1094 | if (insn->offset + insn->len >= func->offset + func->len) |
442f04c3 JP |
1095 | break; |
1096 | insn = list_next_entry(insn, list); | |
1097 | } | |
1098 | ||
1099 | return false; | |
1100 | } | |
1101 | ||
1102 | static int validate_functions(struct objtool_file *file) | |
1103 | { | |
1104 | struct section *sec; | |
1105 | struct symbol *func; | |
1106 | struct instruction *insn; | |
442f04c3 JP |
1107 | int ret, warnings = 0; |
1108 | ||
1109 | list_for_each_entry(sec, &file->elf->sections, list) { | |
a196e171 | 1110 | list_for_each_entry(func, &sec->symbol_list, list) { |
442f04c3 JP |
1111 | if (func->type != STT_FUNC) |
1112 | continue; | |
1113 | ||
74aec058 | 1114 | insn = find_insn(file, sec, func->offset); |
b1547d31 | 1115 | if (!insn) |
442f04c3 | 1116 | continue; |
442f04c3 JP |
1117 | |
1118 | ret = validate_branch(file, insn, 0); | |
1119 | warnings += ret; | |
1120 | } | |
1121 | } | |
1122 | ||
1123 | list_for_each_entry(sec, &file->elf->sections, list) { | |
a196e171 | 1124 | list_for_each_entry(func, &sec->symbol_list, list) { |
442f04c3 JP |
1125 | if (func->type != STT_FUNC) |
1126 | continue; | |
1127 | ||
74aec058 | 1128 | func_for_each_insn(file, func, insn) { |
442f04c3 JP |
1129 | if (insn->visited) |
1130 | continue; | |
1131 | ||
442f04c3 | 1132 | insn->visited = true; |
7e578441 JP |
1133 | |
1134 | if (file->ignore_unreachables || warnings || | |
1135 | ignore_unreachable_insn(func, insn)) | |
1136 | continue; | |
1137 | ||
9cfffb11 JP |
1138 | /* |
1139 | * gcov produces a lot of unreachable | |
1140 | * instructions. If we get an unreachable | |
1141 | * warning and the file has gcov enabled, just | |
1142 | * ignore it, and all other such warnings for | |
1143 | * the file. | |
1144 | */ | |
1145 | if (!file->ignore_unreachables && | |
1146 | gcov_enabled(file)) { | |
1147 | file->ignore_unreachables = true; | |
1148 | continue; | |
1149 | } | |
1150 | ||
7e578441 JP |
1151 | WARN_FUNC("function has unreachable instruction", insn->sec, insn->offset); |
1152 | warnings++; | |
442f04c3 JP |
1153 | } |
1154 | } | |
1155 | } | |
1156 | ||
1157 | return warnings; | |
1158 | } | |
1159 | ||
1160 | static int validate_uncallable_instructions(struct objtool_file *file) | |
1161 | { | |
1162 | struct instruction *insn; | |
1163 | int warnings = 0; | |
1164 | ||
74aec058 | 1165 | for_each_insn(file, insn) { |
442f04c3 JP |
1166 | if (!insn->visited && insn->type == INSN_RETURN) { |
1167 | WARN_FUNC("return instruction outside of a callable function", | |
1168 | insn->sec, insn->offset); | |
1169 | warnings++; | |
1170 | } | |
1171 | } | |
1172 | ||
1173 | return warnings; | |
1174 | } | |
1175 | ||
1176 | static void cleanup(struct objtool_file *file) | |
1177 | { | |
1178 | struct instruction *insn, *tmpinsn; | |
1179 | struct alternative *alt, *tmpalt; | |
1180 | ||
a196e171 | 1181 | list_for_each_entry_safe(insn, tmpinsn, &file->insn_list, list) { |
442f04c3 JP |
1182 | list_for_each_entry_safe(alt, tmpalt, &insn->alts, list) { |
1183 | list_del(&alt->list); | |
1184 | free(alt); | |
1185 | } | |
1186 | list_del(&insn->list); | |
042ba73f | 1187 | hash_del(&insn->hash); |
442f04c3 JP |
1188 | free(insn); |
1189 | } | |
1190 | elf_close(file->elf); | |
1191 | } | |
1192 | ||
1193 | const char * const check_usage[] = { | |
1194 | "objtool check [<options>] file.o", | |
1195 | NULL, | |
1196 | }; | |
1197 | ||
1198 | int cmd_check(int argc, const char **argv) | |
1199 | { | |
1200 | struct objtool_file file; | |
1201 | int ret, warnings = 0; | |
1202 | ||
1203 | const struct option options[] = { | |
1204 | OPT_BOOLEAN('f', "no-fp", &nofp, "Skip frame pointer validation"), | |
1205 | OPT_END(), | |
1206 | }; | |
1207 | ||
1208 | argc = parse_options(argc, argv, options, check_usage, 0); | |
1209 | ||
1210 | if (argc != 1) | |
1211 | usage_with_options(check_usage, options); | |
1212 | ||
1213 | objname = argv[0]; | |
1214 | ||
1215 | file.elf = elf_open(objname); | |
1216 | if (!file.elf) { | |
1217 | fprintf(stderr, "error reading elf file %s\n", objname); | |
1218 | return 1; | |
1219 | } | |
1220 | ||
a196e171 | 1221 | INIT_LIST_HEAD(&file.insn_list); |
042ba73f | 1222 | hash_init(file.insn_hash); |
7e578441 JP |
1223 | file.whitelist = find_section_by_name(file.elf, "__func_stack_frame_non_standard"); |
1224 | file.rodata = find_section_by_name(file.elf, ".rodata"); | |
1225 | file.ignore_unreachables = false; | |
b1547d31 | 1226 | file.c_file = find_section_by_name(file.elf, ".comment"); |
442f04c3 JP |
1227 | |
1228 | ret = decode_sections(&file); | |
1229 | if (ret < 0) | |
1230 | goto out; | |
1231 | warnings += ret; | |
1232 | ||
1233 | ret = validate_functions(&file); | |
1234 | if (ret < 0) | |
1235 | goto out; | |
1236 | warnings += ret; | |
1237 | ||
1238 | ret = validate_uncallable_instructions(&file); | |
1239 | if (ret < 0) | |
1240 | goto out; | |
1241 | warnings += ret; | |
1242 | ||
1243 | out: | |
1244 | cleanup(&file); | |
1245 | ||
1246 | /* ignore warnings for now until we get all the code cleaned up */ | |
1247 | if (ret || warnings) | |
1248 | return 0; | |
1249 | return 0; | |
1250 | } |