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1ccea77e | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
dcc914f4 JP |
2 | /* |
3 | * Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com> | |
dcc914f4 JP |
4 | */ |
5 | ||
6 | #include <string.h> | |
7 | #include <stdlib.h> | |
22682a07 | 8 | #include <inttypes.h> |
8b946cc3 | 9 | #include <sys/mman.h> |
dcc914f4 | 10 | |
7786032e VG |
11 | #include <arch/elf.h> |
12 | #include <objtool/builtin.h> | |
13 | #include <objtool/cfi.h> | |
14 | #include <objtool/arch.h> | |
15 | #include <objtool/check.h> | |
16 | #include <objtool/special.h> | |
17 | #include <objtool/warn.h> | |
18 | #include <objtool/endianness.h> | |
dcc914f4 | 19 | |
ee819aed | 20 | #include <linux/objtool.h> |
dcc914f4 JP |
21 | #include <linux/hashtable.h> |
22 | #include <linux/kernel.h> | |
1e7e4788 | 23 | #include <linux/static_call_types.h> |
dcc914f4 | 24 | |
dcc914f4 JP |
25 | struct alternative { |
26 | struct list_head list; | |
27 | struct instruction *insn; | |
764eef4b | 28 | bool skip_orig; |
dcc914f4 JP |
29 | }; |
30 | ||
8b946cc3 PZ |
31 | static unsigned long nr_cfi, nr_cfi_reused, nr_cfi_cache; |
32 | ||
33 | static struct cfi_init_state initial_func_cfi; | |
34 | static struct cfi_state init_cfi; | |
35 | static struct cfi_state func_cfi; | |
dcc914f4 | 36 | |
627fce14 JP |
37 | struct instruction *find_insn(struct objtool_file *file, |
38 | struct section *sec, unsigned long offset) | |
dcc914f4 JP |
39 | { |
40 | struct instruction *insn; | |
41 | ||
87ecb582 | 42 | hash_for_each_possible(file->insn_hash, insn, hash, sec_offset_hash(sec, offset)) { |
dcc914f4 JP |
43 | if (insn->sec == sec && insn->offset == offset) |
44 | return insn; | |
87ecb582 | 45 | } |
dcc914f4 JP |
46 | |
47 | return NULL; | |
48 | } | |
49 | ||
50 | static struct instruction *next_insn_same_sec(struct objtool_file *file, | |
51 | struct instruction *insn) | |
52 | { | |
53 | struct instruction *next = list_next_entry(insn, list); | |
54 | ||
baa41469 | 55 | if (!next || &next->list == &file->insn_list || next->sec != insn->sec) |
dcc914f4 JP |
56 | return NULL; |
57 | ||
58 | return next; | |
59 | } | |
60 | ||
13810435 JP |
61 | static struct instruction *next_insn_same_func(struct objtool_file *file, |
62 | struct instruction *insn) | |
63 | { | |
64 | struct instruction *next = list_next_entry(insn, list); | |
65 | struct symbol *func = insn->func; | |
66 | ||
67 | if (!func) | |
68 | return NULL; | |
69 | ||
70 | if (&next->list != &file->insn_list && next->func == func) | |
71 | return next; | |
72 | ||
73 | /* Check if we're already in the subfunction: */ | |
74 | if (func == func->cfunc) | |
75 | return NULL; | |
76 | ||
77 | /* Move to the subfunction: */ | |
78 | return find_insn(file, func->cfunc->sec, func->cfunc->offset); | |
79 | } | |
80 | ||
1119d265 JP |
81 | static struct instruction *prev_insn_same_sym(struct objtool_file *file, |
82 | struct instruction *insn) | |
83 | { | |
84 | struct instruction *prev = list_prev_entry(insn, list); | |
85 | ||
86 | if (&prev->list != &file->insn_list && prev->func == insn->func) | |
87 | return prev; | |
88 | ||
89 | return NULL; | |
90 | } | |
91 | ||
f0f70adb | 92 | #define func_for_each_insn(file, func, insn) \ |
13810435 JP |
93 | for (insn = find_insn(file, func->sec, func->offset); \ |
94 | insn; \ | |
95 | insn = next_insn_same_func(file, insn)) | |
96 | ||
dbf4aeb0 PZ |
97 | #define sym_for_each_insn(file, sym, insn) \ |
98 | for (insn = find_insn(file, sym->sec, sym->offset); \ | |
dcc914f4 | 99 | insn && &insn->list != &file->insn_list && \ |
dbf4aeb0 PZ |
100 | insn->sec == sym->sec && \ |
101 | insn->offset < sym->offset + sym->len; \ | |
dcc914f4 JP |
102 | insn = list_next_entry(insn, list)) |
103 | ||
dbf4aeb0 | 104 | #define sym_for_each_insn_continue_reverse(file, sym, insn) \ |
dcc914f4 JP |
105 | for (insn = list_prev_entry(insn, list); \ |
106 | &insn->list != &file->insn_list && \ | |
dbf4aeb0 | 107 | insn->sec == sym->sec && insn->offset >= sym->offset; \ |
dcc914f4 JP |
108 | insn = list_prev_entry(insn, list)) |
109 | ||
110 | #define sec_for_each_insn_from(file, insn) \ | |
111 | for (; insn; insn = next_insn_same_sec(file, insn)) | |
112 | ||
baa41469 JP |
113 | #define sec_for_each_insn_continue(file, insn) \ |
114 | for (insn = next_insn_same_sec(file, insn); insn; \ | |
115 | insn = next_insn_same_sec(file, insn)) | |
dcc914f4 | 116 | |
99033461 JP |
117 | static bool is_jump_table_jump(struct instruction *insn) |
118 | { | |
119 | struct alt_group *alt_group = insn->alt_group; | |
120 | ||
121 | if (insn->jump_table) | |
122 | return true; | |
123 | ||
124 | /* Retpoline alternative for a jump table? */ | |
125 | return alt_group && alt_group->orig_group && | |
126 | alt_group->orig_group->first_insn->jump_table; | |
127 | } | |
128 | ||
0c1ddd33 JP |
129 | static bool is_sibling_call(struct instruction *insn) |
130 | { | |
ecf11ba4 JP |
131 | /* |
132 | * Assume only ELF functions can make sibling calls. This ensures | |
133 | * sibling call detection consistency between vmlinux.o and individual | |
134 | * objects. | |
135 | */ | |
136 | if (!insn->func) | |
137 | return false; | |
138 | ||
0c1ddd33 JP |
139 | /* An indirect jump is either a sibling call or a jump to a table. */ |
140 | if (insn->type == INSN_JUMP_DYNAMIC) | |
99033461 | 141 | return !is_jump_table_jump(insn); |
0c1ddd33 | 142 | |
0c1ddd33 | 143 | /* add_jump_destinations() sets insn->call_dest for sibling calls. */ |
ecf11ba4 | 144 | return (is_static_jump(insn) && insn->call_dest); |
0c1ddd33 JP |
145 | } |
146 | ||
dcc914f4 JP |
147 | /* |
148 | * This checks to see if the given function is a "noreturn" function. | |
149 | * | |
150 | * For global functions which are outside the scope of this object file, we | |
151 | * have to keep a manual list of them. | |
152 | * | |
153 | * For local functions, we have to detect them manually by simply looking for | |
154 | * the lack of a return instruction. | |
dcc914f4 | 155 | */ |
8e25c9f8 JP |
156 | static bool __dead_end_function(struct objtool_file *file, struct symbol *func, |
157 | int recursion) | |
dcc914f4 JP |
158 | { |
159 | int i; | |
160 | struct instruction *insn; | |
161 | bool empty = true; | |
162 | ||
163 | /* | |
164 | * Unfortunately these have to be hard coded because the noreturn | |
165 | * attribute isn't provided in ELF data. | |
166 | */ | |
167 | static const char * const global_noreturns[] = { | |
168 | "__stack_chk_fail", | |
169 | "panic", | |
170 | "do_exit", | |
171 | "do_task_dead", | |
bbda86e9 | 172 | "kthread_exit", |
0e25498f | 173 | "make_task_dead", |
ca3574bd | 174 | "__module_put_and_kthread_exit", |
cead1855 | 175 | "kthread_complete_and_exit", |
dcc914f4 JP |
176 | "__reiserfs_panic", |
177 | "lbug_with_loc", | |
178 | "fortify_panic", | |
b394d468 | 179 | "usercopy_abort", |
684fb246 | 180 | "machine_real_restart", |
1fb466df | 181 | "rewind_stack_and_make_dead", |
33adf80f | 182 | "kunit_try_catch_throw", |
c26acfbb | 183 | "xen_start_kernel", |
9af9dcf1 | 184 | "cpu_bringup_and_idle", |
eae654f1 | 185 | "do_group_exit", |
f9cdf7ca | 186 | "stop_this_cpu", |
105cd685 | 187 | "__invalid_creds", |
385bd430 PZ |
188 | "cpu_startup_entry", |
189 | "__ubsan_handle_builtin_unreachable", | |
2028a255 | 190 | "ex_handler_msr_mce", |
dcc914f4 JP |
191 | }; |
192 | ||
c9bab22b JP |
193 | if (!func) |
194 | return false; | |
195 | ||
dcc914f4 | 196 | if (func->bind == STB_WEAK) |
8e25c9f8 | 197 | return false; |
dcc914f4 JP |
198 | |
199 | if (func->bind == STB_GLOBAL) | |
200 | for (i = 0; i < ARRAY_SIZE(global_noreturns); i++) | |
201 | if (!strcmp(func->name, global_noreturns[i])) | |
8e25c9f8 | 202 | return true; |
dcc914f4 | 203 | |
13810435 | 204 | if (!func->len) |
8e25c9f8 | 205 | return false; |
dcc914f4 | 206 | |
13810435 JP |
207 | insn = find_insn(file, func->sec, func->offset); |
208 | if (!insn->func) | |
8e25c9f8 | 209 | return false; |
13810435 | 210 | |
f0f70adb | 211 | func_for_each_insn(file, func, insn) { |
dcc914f4 JP |
212 | empty = false; |
213 | ||
214 | if (insn->type == INSN_RETURN) | |
8e25c9f8 | 215 | return false; |
dcc914f4 JP |
216 | } |
217 | ||
218 | if (empty) | |
8e25c9f8 | 219 | return false; |
dcc914f4 JP |
220 | |
221 | /* | |
222 | * A function can have a sibling call instead of a return. In that | |
223 | * case, the function's dead-end status depends on whether the target | |
224 | * of the sibling call returns. | |
225 | */ | |
f0f70adb | 226 | func_for_each_insn(file, func, insn) { |
0c1ddd33 | 227 | if (is_sibling_call(insn)) { |
dcc914f4 | 228 | struct instruction *dest = insn->jump_dest; |
dcc914f4 JP |
229 | |
230 | if (!dest) | |
231 | /* sibling call to another file */ | |
8e25c9f8 | 232 | return false; |
dcc914f4 | 233 | |
0c1ddd33 JP |
234 | /* local sibling call */ |
235 | if (recursion == 5) { | |
236 | /* | |
237 | * Infinite recursion: two functions have | |
238 | * sibling calls to each other. This is a very | |
239 | * rare case. It means they aren't dead ends. | |
240 | */ | |
241 | return false; | |
dcc914f4 | 242 | } |
dcc914f4 | 243 | |
0c1ddd33 JP |
244 | return __dead_end_function(file, dest->func, recursion+1); |
245 | } | |
dcc914f4 JP |
246 | } |
247 | ||
8e25c9f8 | 248 | return true; |
dcc914f4 JP |
249 | } |
250 | ||
8e25c9f8 | 251 | static bool dead_end_function(struct objtool_file *file, struct symbol *func) |
dcc914f4 JP |
252 | { |
253 | return __dead_end_function(file, func, 0); | |
254 | } | |
255 | ||
e7c0219b | 256 | static void init_cfi_state(struct cfi_state *cfi) |
baa41469 JP |
257 | { |
258 | int i; | |
259 | ||
dd88a0a0 | 260 | for (i = 0; i < CFI_NUM_REGS; i++) { |
e7c0219b PZ |
261 | cfi->regs[i].base = CFI_UNDEFINED; |
262 | cfi->vals[i].base = CFI_UNDEFINED; | |
dd88a0a0 | 263 | } |
e7c0219b PZ |
264 | cfi->cfa.base = CFI_UNDEFINED; |
265 | cfi->drap_reg = CFI_UNDEFINED; | |
266 | cfi->drap_offset = -1; | |
267 | } | |
268 | ||
753da417 JP |
269 | static void init_insn_state(struct objtool_file *file, struct insn_state *state, |
270 | struct section *sec) | |
e7c0219b PZ |
271 | { |
272 | memset(state, 0, sizeof(*state)); | |
273 | init_cfi_state(&state->cfi); | |
932f8e98 PZ |
274 | |
275 | /* | |
276 | * We need the full vmlinux for noinstr validation, otherwise we can | |
277 | * not correctly determine insn->call_dest->sec (external symbols do | |
278 | * not have a section). | |
279 | */ | |
753da417 | 280 | if (opts.link && opts.noinstr && sec) |
932f8e98 | 281 | state->noinstr = sec->noinstr; |
baa41469 JP |
282 | } |
283 | ||
8b946cc3 PZ |
284 | static struct cfi_state *cfi_alloc(void) |
285 | { | |
286 | struct cfi_state *cfi = calloc(sizeof(struct cfi_state), 1); | |
287 | if (!cfi) { | |
288 | WARN("calloc failed"); | |
289 | exit(1); | |
290 | } | |
291 | nr_cfi++; | |
292 | return cfi; | |
293 | } | |
294 | ||
295 | static int cfi_bits; | |
296 | static struct hlist_head *cfi_hash; | |
297 | ||
298 | static inline bool cficmp(struct cfi_state *cfi1, struct cfi_state *cfi2) | |
299 | { | |
300 | return memcmp((void *)cfi1 + sizeof(cfi1->hash), | |
301 | (void *)cfi2 + sizeof(cfi2->hash), | |
302 | sizeof(struct cfi_state) - sizeof(struct hlist_node)); | |
303 | } | |
304 | ||
305 | static inline u32 cfi_key(struct cfi_state *cfi) | |
306 | { | |
307 | return jhash((void *)cfi + sizeof(cfi->hash), | |
308 | sizeof(*cfi) - sizeof(cfi->hash), 0); | |
309 | } | |
310 | ||
311 | static struct cfi_state *cfi_hash_find_or_add(struct cfi_state *cfi) | |
312 | { | |
313 | struct hlist_head *head = &cfi_hash[hash_min(cfi_key(cfi), cfi_bits)]; | |
314 | struct cfi_state *obj; | |
315 | ||
316 | hlist_for_each_entry(obj, head, hash) { | |
317 | if (!cficmp(cfi, obj)) { | |
318 | nr_cfi_cache++; | |
319 | return obj; | |
320 | } | |
321 | } | |
322 | ||
323 | obj = cfi_alloc(); | |
324 | *obj = *cfi; | |
325 | hlist_add_head(&obj->hash, head); | |
326 | ||
327 | return obj; | |
328 | } | |
329 | ||
330 | static void cfi_hash_add(struct cfi_state *cfi) | |
331 | { | |
332 | struct hlist_head *head = &cfi_hash[hash_min(cfi_key(cfi), cfi_bits)]; | |
333 | ||
334 | hlist_add_head(&cfi->hash, head); | |
335 | } | |
336 | ||
337 | static void *cfi_hash_alloc(unsigned long size) | |
338 | { | |
339 | cfi_bits = max(10, ilog2(size)); | |
340 | cfi_hash = mmap(NULL, sizeof(struct hlist_head) << cfi_bits, | |
341 | PROT_READ|PROT_WRITE, | |
342 | MAP_PRIVATE|MAP_ANON, -1, 0); | |
343 | if (cfi_hash == (void *)-1L) { | |
344 | WARN("mmap fail cfi_hash"); | |
345 | cfi_hash = NULL; | |
2daf7fab | 346 | } else if (opts.stats) { |
8b946cc3 PZ |
347 | printf("cfi_bits: %d\n", cfi_bits); |
348 | } | |
349 | ||
350 | return cfi_hash; | |
351 | } | |
352 | ||
353 | static unsigned long nr_insns; | |
354 | static unsigned long nr_insns_visited; | |
355 | ||
dcc914f4 JP |
356 | /* |
357 | * Call the arch-specific instruction decoder for all the instructions and add | |
358 | * them to the global instruction list. | |
359 | */ | |
360 | static int decode_instructions(struct objtool_file *file) | |
361 | { | |
362 | struct section *sec; | |
363 | struct symbol *func; | |
364 | unsigned long offset; | |
365 | struct instruction *insn; | |
366 | int ret; | |
367 | ||
baa41469 | 368 | for_each_sec(file, sec) { |
dcc914f4 JP |
369 | |
370 | if (!(sec->sh.sh_flags & SHF_EXECINSTR)) | |
371 | continue; | |
372 | ||
627fce14 JP |
373 | if (strcmp(sec->name, ".altinstr_replacement") && |
374 | strcmp(sec->name, ".altinstr_aux") && | |
375 | strncmp(sec->name, ".discard.", 9)) | |
376 | sec->text = true; | |
377 | ||
0cc9ac8d | 378 | if (!strcmp(sec->name, ".noinstr.text") || |
951ddecf PZ |
379 | !strcmp(sec->name, ".entry.text") || |
380 | !strncmp(sec->name, ".text.__x86.", 12)) | |
c4a33939 PZ |
381 | sec->noinstr = true; |
382 | ||
fe255fe6 | 383 | for (offset = 0; offset < sec->sh.sh_size; offset += insn->len) { |
dcc914f4 | 384 | insn = malloc(sizeof(*insn)); |
baa41469 JP |
385 | if (!insn) { |
386 | WARN("malloc failed"); | |
387 | return -1; | |
388 | } | |
dcc914f4 | 389 | memset(insn, 0, sizeof(*insn)); |
dcc914f4 | 390 | INIT_LIST_HEAD(&insn->alts); |
65ea47dc | 391 | INIT_LIST_HEAD(&insn->stack_ops); |
89bc853e | 392 | INIT_LIST_HEAD(&insn->call_node); |
baa41469 | 393 | |
dcc914f4 JP |
394 | insn->sec = sec; |
395 | insn->offset = offset; | |
396 | ||
db2b0c5d | 397 | ret = arch_decode_instruction(file, sec, offset, |
fe255fe6 | 398 | sec->sh.sh_size - offset, |
dcc914f4 | 399 | &insn->len, &insn->type, |
baa41469 | 400 | &insn->immediate, |
65ea47dc | 401 | &insn->stack_ops); |
dcc914f4 | 402 | if (ret) |
b7037983 | 403 | goto err; |
dcc914f4 | 404 | |
0e5b613b PZ |
405 | /* |
406 | * By default, "ud2" is a dead end unless otherwise | |
407 | * annotated, because GCC 7 inserts it for certain | |
408 | * divide-by-zero cases. | |
409 | */ | |
410 | if (insn->type == INSN_BUG) | |
411 | insn->dead_end = true; | |
412 | ||
87ecb582 | 413 | hash_add(file->insn_hash, &insn->hash, sec_offset_hash(sec, insn->offset)); |
dcc914f4 | 414 | list_add_tail(&insn->list, &file->insn_list); |
1e11f3fd | 415 | nr_insns++; |
dcc914f4 JP |
416 | } |
417 | ||
418 | list_for_each_entry(func, &sec->symbol_list, list) { | |
e10cd8fe | 419 | if (func->type != STT_FUNC || func->alias != func) |
dcc914f4 JP |
420 | continue; |
421 | ||
422 | if (!find_insn(file, sec, func->offset)) { | |
423 | WARN("%s(): can't find starting instruction", | |
424 | func->name); | |
425 | return -1; | |
426 | } | |
427 | ||
08f87a93 | 428 | sym_for_each_insn(file, func, insn) { |
e10cd8fe | 429 | insn->func = func; |
89bc853e | 430 | if (insn->type == INSN_ENDBR && list_empty(&insn->call_node)) { |
08f87a93 | 431 | if (insn->offset == insn->func->offset) { |
89bc853e | 432 | list_add_tail(&insn->call_node, &file->endbr_list); |
08f87a93 PZ |
433 | file->nr_endbr++; |
434 | } else { | |
435 | file->nr_endbr_int++; | |
436 | } | |
437 | } | |
438 | } | |
dcc914f4 JP |
439 | } |
440 | } | |
441 | ||
2daf7fab | 442 | if (opts.stats) |
1e11f3fd PZ |
443 | printf("nr_insns: %lu\n", nr_insns); |
444 | ||
dcc914f4 | 445 | return 0; |
b7037983 KB |
446 | |
447 | err: | |
448 | free(insn); | |
449 | return ret; | |
dcc914f4 JP |
450 | } |
451 | ||
db2b0c5d PZ |
452 | /* |
453 | * Read the pv_ops[] .data table to find the static initialized values. | |
454 | */ | |
455 | static int add_pv_ops(struct objtool_file *file, const char *symname) | |
456 | { | |
457 | struct symbol *sym, *func; | |
458 | unsigned long off, end; | |
459 | struct reloc *rel; | |
460 | int idx; | |
461 | ||
462 | sym = find_symbol_by_name(file->elf, symname); | |
463 | if (!sym) | |
464 | return 0; | |
465 | ||
466 | off = sym->offset; | |
467 | end = off + sym->len; | |
468 | for (;;) { | |
469 | rel = find_reloc_by_dest_range(file->elf, sym->sec, off, end - off); | |
470 | if (!rel) | |
471 | break; | |
472 | ||
473 | func = rel->sym; | |
474 | if (func->type == STT_SECTION) | |
475 | func = find_symbol_by_offset(rel->sym->sec, rel->addend); | |
476 | ||
477 | idx = (rel->offset - sym->offset) / sizeof(unsigned long); | |
478 | ||
479 | objtool_pv_add(file, idx, func); | |
480 | ||
481 | off = rel->offset + 1; | |
482 | if (off > end) | |
483 | break; | |
484 | } | |
485 | ||
486 | return 0; | |
487 | } | |
488 | ||
489 | /* | |
490 | * Allocate and initialize file->pv_ops[]. | |
491 | */ | |
492 | static int init_pv_ops(struct objtool_file *file) | |
493 | { | |
494 | static const char *pv_ops_tables[] = { | |
495 | "pv_ops", | |
496 | "xen_cpu_ops", | |
497 | "xen_irq_ops", | |
498 | "xen_mmu_ops", | |
499 | NULL, | |
500 | }; | |
501 | const char *pv_ops; | |
502 | struct symbol *sym; | |
503 | int idx, nr; | |
504 | ||
2daf7fab | 505 | if (!opts.noinstr) |
db2b0c5d PZ |
506 | return 0; |
507 | ||
508 | file->pv_ops = NULL; | |
509 | ||
510 | sym = find_symbol_by_name(file->elf, "pv_ops"); | |
511 | if (!sym) | |
512 | return 0; | |
513 | ||
514 | nr = sym->len / sizeof(unsigned long); | |
515 | file->pv_ops = calloc(sizeof(struct pv_state), nr); | |
516 | if (!file->pv_ops) | |
517 | return -1; | |
518 | ||
519 | for (idx = 0; idx < nr; idx++) | |
520 | INIT_LIST_HEAD(&file->pv_ops[idx].targets); | |
521 | ||
522 | for (idx = 0; (pv_ops = pv_ops_tables[idx]); idx++) | |
523 | add_pv_ops(file, pv_ops); | |
524 | ||
525 | return 0; | |
526 | } | |
527 | ||
6b5dd716 ST |
528 | static struct instruction *find_last_insn(struct objtool_file *file, |
529 | struct section *sec) | |
530 | { | |
531 | struct instruction *insn = NULL; | |
532 | unsigned int offset; | |
fe255fe6 | 533 | unsigned int end = (sec->sh.sh_size > 10) ? sec->sh.sh_size - 10 : 0; |
6b5dd716 | 534 | |
fe255fe6 | 535 | for (offset = sec->sh.sh_size - 1; offset >= end && !insn; offset--) |
6b5dd716 ST |
536 | insn = find_insn(file, sec, offset); |
537 | ||
538 | return insn; | |
539 | } | |
540 | ||
dcc914f4 | 541 | /* |
649ea4d5 | 542 | * Mark "ud2" instructions and manually annotated dead ends. |
dcc914f4 JP |
543 | */ |
544 | static int add_dead_ends(struct objtool_file *file) | |
545 | { | |
546 | struct section *sec; | |
f1974222 | 547 | struct reloc *reloc; |
dcc914f4 | 548 | struct instruction *insn; |
dcc914f4 | 549 | |
649ea4d5 JP |
550 | /* |
551 | * Check for manually annotated dead ends. | |
552 | */ | |
dcc914f4 JP |
553 | sec = find_section_by_name(file->elf, ".rela.discard.unreachable"); |
554 | if (!sec) | |
649ea4d5 | 555 | goto reachable; |
dcc914f4 | 556 | |
f1974222 MH |
557 | list_for_each_entry(reloc, &sec->reloc_list, list) { |
558 | if (reloc->sym->type != STT_SECTION) { | |
dcc914f4 JP |
559 | WARN("unexpected relocation symbol type in %s", sec->name); |
560 | return -1; | |
561 | } | |
f1974222 | 562 | insn = find_insn(file, reloc->sym->sec, reloc->addend); |
dcc914f4 JP |
563 | if (insn) |
564 | insn = list_prev_entry(insn, list); | |
fe255fe6 | 565 | else if (reloc->addend == reloc->sym->sec->sh.sh_size) { |
f1974222 | 566 | insn = find_last_insn(file, reloc->sym->sec); |
6b5dd716 | 567 | if (!insn) { |
22682a07 | 568 | WARN("can't find unreachable insn at %s+0x%" PRIx64, |
f1974222 | 569 | reloc->sym->sec->name, reloc->addend); |
dcc914f4 JP |
570 | return -1; |
571 | } | |
572 | } else { | |
22682a07 | 573 | WARN("can't find unreachable insn at %s+0x%" PRIx64, |
f1974222 | 574 | reloc->sym->sec->name, reloc->addend); |
dcc914f4 JP |
575 | return -1; |
576 | } | |
577 | ||
578 | insn->dead_end = true; | |
579 | } | |
580 | ||
649ea4d5 JP |
581 | reachable: |
582 | /* | |
583 | * These manually annotated reachable checks are needed for GCC 4.4, | |
584 | * where the Linux unreachable() macro isn't supported. In that case | |
585 | * GCC doesn't know the "ud2" is fatal, so it generates code as if it's | |
586 | * not a dead end. | |
587 | */ | |
588 | sec = find_section_by_name(file->elf, ".rela.discard.reachable"); | |
589 | if (!sec) | |
590 | return 0; | |
591 | ||
f1974222 MH |
592 | list_for_each_entry(reloc, &sec->reloc_list, list) { |
593 | if (reloc->sym->type != STT_SECTION) { | |
649ea4d5 JP |
594 | WARN("unexpected relocation symbol type in %s", sec->name); |
595 | return -1; | |
596 | } | |
f1974222 | 597 | insn = find_insn(file, reloc->sym->sec, reloc->addend); |
649ea4d5 JP |
598 | if (insn) |
599 | insn = list_prev_entry(insn, list); | |
fe255fe6 | 600 | else if (reloc->addend == reloc->sym->sec->sh.sh_size) { |
f1974222 | 601 | insn = find_last_insn(file, reloc->sym->sec); |
6b5dd716 | 602 | if (!insn) { |
22682a07 | 603 | WARN("can't find reachable insn at %s+0x%" PRIx64, |
f1974222 | 604 | reloc->sym->sec->name, reloc->addend); |
649ea4d5 JP |
605 | return -1; |
606 | } | |
607 | } else { | |
22682a07 | 608 | WARN("can't find reachable insn at %s+0x%" PRIx64, |
f1974222 | 609 | reloc->sym->sec->name, reloc->addend); |
649ea4d5 JP |
610 | return -1; |
611 | } | |
612 | ||
613 | insn->dead_end = false; | |
614 | } | |
615 | ||
dcc914f4 JP |
616 | return 0; |
617 | } | |
618 | ||
1e7e4788 JP |
619 | static int create_static_call_sections(struct objtool_file *file) |
620 | { | |
ef47cc01 | 621 | struct section *sec; |
1e7e4788 JP |
622 | struct static_call_site *site; |
623 | struct instruction *insn; | |
624 | struct symbol *key_sym; | |
625 | char *key_name, *tmp; | |
626 | int idx; | |
627 | ||
628 | sec = find_section_by_name(file->elf, ".static_call_sites"); | |
629 | if (sec) { | |
630 | INIT_LIST_HEAD(&file->static_call_list); | |
631 | WARN("file already has .static_call_sites section, skipping"); | |
632 | return 0; | |
633 | } | |
634 | ||
635 | if (list_empty(&file->static_call_list)) | |
636 | return 0; | |
637 | ||
638 | idx = 0; | |
43d5430a | 639 | list_for_each_entry(insn, &file->static_call_list, call_node) |
1e7e4788 JP |
640 | idx++; |
641 | ||
642 | sec = elf_create_section(file->elf, ".static_call_sites", SHF_WRITE, | |
643 | sizeof(struct static_call_site), idx); | |
644 | if (!sec) | |
645 | return -1; | |
646 | ||
1e7e4788 | 647 | idx = 0; |
43d5430a | 648 | list_for_each_entry(insn, &file->static_call_list, call_node) { |
1e7e4788 JP |
649 | |
650 | site = (struct static_call_site *)sec->data->d_buf + idx; | |
651 | memset(site, 0, sizeof(struct static_call_site)); | |
652 | ||
653 | /* populate reloc for 'addr' */ | |
ef47cc01 PZ |
654 | if (elf_add_reloc_to_insn(file->elf, sec, |
655 | idx * sizeof(struct static_call_site), | |
656 | R_X86_64_PC32, | |
657 | insn->sec, insn->offset)) | |
44f6a7c0 | 658 | return -1; |
1e7e4788 JP |
659 | |
660 | /* find key symbol */ | |
661 | key_name = strdup(insn->call_dest->name); | |
662 | if (!key_name) { | |
663 | perror("strdup"); | |
664 | return -1; | |
665 | } | |
666 | if (strncmp(key_name, STATIC_CALL_TRAMP_PREFIX_STR, | |
667 | STATIC_CALL_TRAMP_PREFIX_LEN)) { | |
668 | WARN("static_call: trampoline name malformed: %s", key_name); | |
669 | return -1; | |
670 | } | |
671 | tmp = key_name + STATIC_CALL_TRAMP_PREFIX_LEN - STATIC_CALL_KEY_PREFIX_LEN; | |
672 | memcpy(tmp, STATIC_CALL_KEY_PREFIX_STR, STATIC_CALL_KEY_PREFIX_LEN); | |
673 | ||
674 | key_sym = find_symbol_by_name(file->elf, tmp); | |
675 | if (!key_sym) { | |
2daf7fab | 676 | if (!opts.module) { |
73f44fe1 JP |
677 | WARN("static_call: can't find static_call_key symbol: %s", tmp); |
678 | return -1; | |
679 | } | |
680 | ||
681 | /* | |
682 | * For modules(), the key might not be exported, which | |
683 | * means the module can make static calls but isn't | |
684 | * allowed to change them. | |
685 | * | |
686 | * In that case we temporarily set the key to be the | |
687 | * trampoline address. This is fixed up in | |
688 | * static_call_add_module(). | |
689 | */ | |
690 | key_sym = insn->call_dest; | |
1e7e4788 JP |
691 | } |
692 | free(key_name); | |
693 | ||
694 | /* populate reloc for 'key' */ | |
ef47cc01 PZ |
695 | if (elf_add_reloc(file->elf, sec, |
696 | idx * sizeof(struct static_call_site) + 4, | |
697 | R_X86_64_PC32, key_sym, | |
698 | is_sibling_call(insn) * STATIC_CALL_SITE_TAIL)) | |
1e7e4788 | 699 | return -1; |
1e7e4788 JP |
700 | |
701 | idx++; | |
702 | } | |
703 | ||
1e7e4788 JP |
704 | return 0; |
705 | } | |
706 | ||
134ab5bd PZ |
707 | static int create_retpoline_sites_sections(struct objtool_file *file) |
708 | { | |
709 | struct instruction *insn; | |
710 | struct section *sec; | |
711 | int idx; | |
712 | ||
713 | sec = find_section_by_name(file->elf, ".retpoline_sites"); | |
714 | if (sec) { | |
715 | WARN("file already has .retpoline_sites, skipping"); | |
716 | return 0; | |
717 | } | |
718 | ||
719 | idx = 0; | |
720 | list_for_each_entry(insn, &file->retpoline_call_list, call_node) | |
721 | idx++; | |
722 | ||
723 | if (!idx) | |
724 | return 0; | |
725 | ||
726 | sec = elf_create_section(file->elf, ".retpoline_sites", 0, | |
727 | sizeof(int), idx); | |
728 | if (!sec) { | |
729 | WARN("elf_create_section: .retpoline_sites"); | |
730 | return -1; | |
731 | } | |
732 | ||
733 | idx = 0; | |
734 | list_for_each_entry(insn, &file->retpoline_call_list, call_node) { | |
735 | ||
736 | int *site = (int *)sec->data->d_buf + idx; | |
737 | *site = 0; | |
738 | ||
739 | if (elf_add_reloc_to_insn(file->elf, sec, | |
740 | idx * sizeof(int), | |
741 | R_X86_64_PC32, | |
742 | insn->sec, insn->offset)) { | |
743 | WARN("elf_add_reloc_to_insn: .retpoline_sites"); | |
744 | return -1; | |
745 | } | |
746 | ||
747 | idx++; | |
748 | } | |
749 | ||
750 | return 0; | |
751 | } | |
752 | ||
d9e9d230 PZ |
753 | static int create_return_sites_sections(struct objtool_file *file) |
754 | { | |
755 | struct instruction *insn; | |
756 | struct section *sec; | |
757 | int idx; | |
758 | ||
759 | sec = find_section_by_name(file->elf, ".return_sites"); | |
760 | if (sec) { | |
761 | WARN("file already has .return_sites, skipping"); | |
762 | return 0; | |
763 | } | |
764 | ||
765 | idx = 0; | |
766 | list_for_each_entry(insn, &file->return_thunk_list, call_node) | |
767 | idx++; | |
768 | ||
769 | if (!idx) | |
770 | return 0; | |
771 | ||
772 | sec = elf_create_section(file->elf, ".return_sites", 0, | |
773 | sizeof(int), idx); | |
774 | if (!sec) { | |
775 | WARN("elf_create_section: .return_sites"); | |
776 | return -1; | |
777 | } | |
778 | ||
779 | idx = 0; | |
780 | list_for_each_entry(insn, &file->return_thunk_list, call_node) { | |
781 | ||
782 | int *site = (int *)sec->data->d_buf + idx; | |
783 | *site = 0; | |
784 | ||
785 | if (elf_add_reloc_to_insn(file->elf, sec, | |
786 | idx * sizeof(int), | |
787 | R_X86_64_PC32, | |
788 | insn->sec, insn->offset)) { | |
789 | WARN("elf_add_reloc_to_insn: .return_sites"); | |
790 | return -1; | |
791 | } | |
792 | ||
793 | idx++; | |
794 | } | |
795 | ||
796 | return 0; | |
797 | } | |
798 | ||
89bc853e PZ |
799 | static int create_ibt_endbr_seal_sections(struct objtool_file *file) |
800 | { | |
801 | struct instruction *insn; | |
802 | struct section *sec; | |
803 | int idx; | |
804 | ||
805 | sec = find_section_by_name(file->elf, ".ibt_endbr_seal"); | |
806 | if (sec) { | |
807 | WARN("file already has .ibt_endbr_seal, skipping"); | |
808 | return 0; | |
809 | } | |
810 | ||
811 | idx = 0; | |
812 | list_for_each_entry(insn, &file->endbr_list, call_node) | |
813 | idx++; | |
814 | ||
2daf7fab | 815 | if (opts.stats) { |
89bc853e PZ |
816 | printf("ibt: ENDBR at function start: %d\n", file->nr_endbr); |
817 | printf("ibt: ENDBR inside functions: %d\n", file->nr_endbr_int); | |
818 | printf("ibt: superfluous ENDBR: %d\n", idx); | |
819 | } | |
820 | ||
821 | if (!idx) | |
822 | return 0; | |
823 | ||
824 | sec = elf_create_section(file->elf, ".ibt_endbr_seal", 0, | |
825 | sizeof(int), idx); | |
826 | if (!sec) { | |
827 | WARN("elf_create_section: .ibt_endbr_seal"); | |
828 | return -1; | |
829 | } | |
830 | ||
831 | idx = 0; | |
832 | list_for_each_entry(insn, &file->endbr_list, call_node) { | |
833 | ||
834 | int *site = (int *)sec->data->d_buf + idx; | |
835 | *site = 0; | |
836 | ||
837 | if (elf_add_reloc_to_insn(file->elf, sec, | |
838 | idx * sizeof(int), | |
839 | R_X86_64_PC32, | |
840 | insn->sec, insn->offset)) { | |
841 | WARN("elf_add_reloc_to_insn: .ibt_endbr_seal"); | |
842 | return -1; | |
843 | } | |
844 | ||
845 | idx++; | |
846 | } | |
847 | ||
848 | return 0; | |
849 | } | |
850 | ||
99d00215 PZ |
851 | static int create_mcount_loc_sections(struct objtool_file *file) |
852 | { | |
ef47cc01 | 853 | struct section *sec; |
99d00215 PZ |
854 | unsigned long *loc; |
855 | struct instruction *insn; | |
856 | int idx; | |
857 | ||
858 | sec = find_section_by_name(file->elf, "__mcount_loc"); | |
859 | if (sec) { | |
860 | INIT_LIST_HEAD(&file->mcount_loc_list); | |
861 | WARN("file already has __mcount_loc section, skipping"); | |
862 | return 0; | |
863 | } | |
864 | ||
865 | if (list_empty(&file->mcount_loc_list)) | |
866 | return 0; | |
867 | ||
868 | idx = 0; | |
c509331b | 869 | list_for_each_entry(insn, &file->mcount_loc_list, call_node) |
99d00215 PZ |
870 | idx++; |
871 | ||
872 | sec = elf_create_section(file->elf, "__mcount_loc", 0, sizeof(unsigned long), idx); | |
873 | if (!sec) | |
874 | return -1; | |
875 | ||
99d00215 | 876 | idx = 0; |
c509331b | 877 | list_for_each_entry(insn, &file->mcount_loc_list, call_node) { |
99d00215 PZ |
878 | |
879 | loc = (unsigned long *)sec->data->d_buf + idx; | |
880 | memset(loc, 0, sizeof(unsigned long)); | |
881 | ||
ef47cc01 PZ |
882 | if (elf_add_reloc_to_insn(file->elf, sec, |
883 | idx * sizeof(unsigned long), | |
884 | R_X86_64_64, | |
885 | insn->sec, insn->offset)) | |
99d00215 | 886 | return -1; |
99d00215 PZ |
887 | |
888 | idx++; | |
889 | } | |
890 | ||
99d00215 PZ |
891 | return 0; |
892 | } | |
893 | ||
dcc914f4 JP |
894 | /* |
895 | * Warnings shouldn't be reported for ignored functions. | |
896 | */ | |
897 | static void add_ignores(struct objtool_file *file) | |
898 | { | |
899 | struct instruction *insn; | |
900 | struct section *sec; | |
901 | struct symbol *func; | |
f1974222 | 902 | struct reloc *reloc; |
dcc914f4 | 903 | |
aaf5c623 PZ |
904 | sec = find_section_by_name(file->elf, ".rela.discard.func_stack_frame_non_standard"); |
905 | if (!sec) | |
906 | return; | |
dcc914f4 | 907 | |
f1974222 MH |
908 | list_for_each_entry(reloc, &sec->reloc_list, list) { |
909 | switch (reloc->sym->type) { | |
aaf5c623 | 910 | case STT_FUNC: |
f1974222 | 911 | func = reloc->sym; |
aaf5c623 PZ |
912 | break; |
913 | ||
914 | case STT_SECTION: | |
f1974222 | 915 | func = find_func_by_offset(reloc->sym->sec, reloc->addend); |
7acfe531 | 916 | if (!func) |
dcc914f4 | 917 | continue; |
aaf5c623 | 918 | break; |
dcc914f4 | 919 | |
aaf5c623 | 920 | default: |
f1974222 | 921 | WARN("unexpected relocation symbol type in %s: %d", sec->name, reloc->sym->type); |
aaf5c623 | 922 | continue; |
dcc914f4 | 923 | } |
aaf5c623 | 924 | |
f0f70adb | 925 | func_for_each_insn(file, func, insn) |
aaf5c623 | 926 | insn->ignore = true; |
dcc914f4 JP |
927 | } |
928 | } | |
929 | ||
ea24213d PZ |
930 | /* |
931 | * This is a whitelist of functions that is allowed to be called with AC set. | |
932 | * The list is meant to be minimal and only contains compiler instrumentation | |
933 | * ABI and a few functions used to implement *_{to,from}_user() functions. | |
934 | * | |
935 | * These functions must not directly change AC, but may PUSHF/POPF. | |
936 | */ | |
937 | static const char *uaccess_safe_builtin[] = { | |
938 | /* KASAN */ | |
939 | "kasan_report", | |
f00748bf | 940 | "kasan_check_range", |
ea24213d PZ |
941 | /* KASAN out-of-line */ |
942 | "__asan_loadN_noabort", | |
943 | "__asan_load1_noabort", | |
944 | "__asan_load2_noabort", | |
945 | "__asan_load4_noabort", | |
946 | "__asan_load8_noabort", | |
947 | "__asan_load16_noabort", | |
948 | "__asan_storeN_noabort", | |
949 | "__asan_store1_noabort", | |
950 | "__asan_store2_noabort", | |
951 | "__asan_store4_noabort", | |
952 | "__asan_store8_noabort", | |
953 | "__asan_store16_noabort", | |
b0b8e56b JH |
954 | "__kasan_check_read", |
955 | "__kasan_check_write", | |
ea24213d PZ |
956 | /* KASAN in-line */ |
957 | "__asan_report_load_n_noabort", | |
958 | "__asan_report_load1_noabort", | |
959 | "__asan_report_load2_noabort", | |
960 | "__asan_report_load4_noabort", | |
961 | "__asan_report_load8_noabort", | |
962 | "__asan_report_load16_noabort", | |
963 | "__asan_report_store_n_noabort", | |
964 | "__asan_report_store1_noabort", | |
965 | "__asan_report_store2_noabort", | |
966 | "__asan_report_store4_noabort", | |
967 | "__asan_report_store8_noabort", | |
968 | "__asan_report_store16_noabort", | |
5f5c9712 | 969 | /* KCSAN */ |
9967683c | 970 | "__kcsan_check_access", |
0525bd82 ME |
971 | "__kcsan_mb", |
972 | "__kcsan_wmb", | |
973 | "__kcsan_rmb", | |
974 | "__kcsan_release", | |
5f5c9712 ME |
975 | "kcsan_found_watchpoint", |
976 | "kcsan_setup_watchpoint", | |
9967683c | 977 | "kcsan_check_scoped_accesses", |
50a19ad4 ME |
978 | "kcsan_disable_current", |
979 | "kcsan_enable_current_nowarn", | |
5f5c9712 ME |
980 | /* KCSAN/TSAN */ |
981 | "__tsan_func_entry", | |
982 | "__tsan_func_exit", | |
983 | "__tsan_read_range", | |
984 | "__tsan_write_range", | |
985 | "__tsan_read1", | |
986 | "__tsan_read2", | |
987 | "__tsan_read4", | |
988 | "__tsan_read8", | |
989 | "__tsan_read16", | |
990 | "__tsan_write1", | |
991 | "__tsan_write2", | |
992 | "__tsan_write4", | |
993 | "__tsan_write8", | |
994 | "__tsan_write16", | |
a81b3759 ME |
995 | "__tsan_read_write1", |
996 | "__tsan_read_write2", | |
997 | "__tsan_read_write4", | |
998 | "__tsan_read_write8", | |
999 | "__tsan_read_write16", | |
883957b1 ME |
1000 | "__tsan_atomic8_load", |
1001 | "__tsan_atomic16_load", | |
1002 | "__tsan_atomic32_load", | |
1003 | "__tsan_atomic64_load", | |
1004 | "__tsan_atomic8_store", | |
1005 | "__tsan_atomic16_store", | |
1006 | "__tsan_atomic32_store", | |
1007 | "__tsan_atomic64_store", | |
1008 | "__tsan_atomic8_exchange", | |
1009 | "__tsan_atomic16_exchange", | |
1010 | "__tsan_atomic32_exchange", | |
1011 | "__tsan_atomic64_exchange", | |
1012 | "__tsan_atomic8_fetch_add", | |
1013 | "__tsan_atomic16_fetch_add", | |
1014 | "__tsan_atomic32_fetch_add", | |
1015 | "__tsan_atomic64_fetch_add", | |
1016 | "__tsan_atomic8_fetch_sub", | |
1017 | "__tsan_atomic16_fetch_sub", | |
1018 | "__tsan_atomic32_fetch_sub", | |
1019 | "__tsan_atomic64_fetch_sub", | |
1020 | "__tsan_atomic8_fetch_and", | |
1021 | "__tsan_atomic16_fetch_and", | |
1022 | "__tsan_atomic32_fetch_and", | |
1023 | "__tsan_atomic64_fetch_and", | |
1024 | "__tsan_atomic8_fetch_or", | |
1025 | "__tsan_atomic16_fetch_or", | |
1026 | "__tsan_atomic32_fetch_or", | |
1027 | "__tsan_atomic64_fetch_or", | |
1028 | "__tsan_atomic8_fetch_xor", | |
1029 | "__tsan_atomic16_fetch_xor", | |
1030 | "__tsan_atomic32_fetch_xor", | |
1031 | "__tsan_atomic64_fetch_xor", | |
1032 | "__tsan_atomic8_fetch_nand", | |
1033 | "__tsan_atomic16_fetch_nand", | |
1034 | "__tsan_atomic32_fetch_nand", | |
1035 | "__tsan_atomic64_fetch_nand", | |
1036 | "__tsan_atomic8_compare_exchange_strong", | |
1037 | "__tsan_atomic16_compare_exchange_strong", | |
1038 | "__tsan_atomic32_compare_exchange_strong", | |
1039 | "__tsan_atomic64_compare_exchange_strong", | |
1040 | "__tsan_atomic8_compare_exchange_weak", | |
1041 | "__tsan_atomic16_compare_exchange_weak", | |
1042 | "__tsan_atomic32_compare_exchange_weak", | |
1043 | "__tsan_atomic64_compare_exchange_weak", | |
1044 | "__tsan_atomic8_compare_exchange_val", | |
1045 | "__tsan_atomic16_compare_exchange_val", | |
1046 | "__tsan_atomic32_compare_exchange_val", | |
1047 | "__tsan_atomic64_compare_exchange_val", | |
1048 | "__tsan_atomic_thread_fence", | |
1049 | "__tsan_atomic_signal_fence", | |
ea24213d PZ |
1050 | /* KCOV */ |
1051 | "write_comp_data", | |
ae033f08 | 1052 | "check_kcov_mode", |
ea24213d PZ |
1053 | "__sanitizer_cov_trace_pc", |
1054 | "__sanitizer_cov_trace_const_cmp1", | |
1055 | "__sanitizer_cov_trace_const_cmp2", | |
1056 | "__sanitizer_cov_trace_const_cmp4", | |
1057 | "__sanitizer_cov_trace_const_cmp8", | |
1058 | "__sanitizer_cov_trace_cmp1", | |
1059 | "__sanitizer_cov_trace_cmp2", | |
1060 | "__sanitizer_cov_trace_cmp4", | |
1061 | "__sanitizer_cov_trace_cmp8", | |
36b1c700 | 1062 | "__sanitizer_cov_trace_switch", |
ea24213d PZ |
1063 | /* UBSAN */ |
1064 | "ubsan_type_mismatch_common", | |
1065 | "__ubsan_handle_type_mismatch", | |
1066 | "__ubsan_handle_type_mismatch_v1", | |
9a50dcaf | 1067 | "__ubsan_handle_shift_out_of_bounds", |
ea24213d PZ |
1068 | /* misc */ |
1069 | "csum_partial_copy_generic", | |
ec6347bb DW |
1070 | "copy_mc_fragile", |
1071 | "copy_mc_fragile_handle_tail", | |
5da8e4a6 | 1072 | "copy_mc_enhanced_fast_string", |
ea24213d PZ |
1073 | "ftrace_likely_update", /* CONFIG_TRACE_BRANCH_PROFILING */ |
1074 | NULL | |
1075 | }; | |
1076 | ||
1077 | static void add_uaccess_safe(struct objtool_file *file) | |
1078 | { | |
1079 | struct symbol *func; | |
1080 | const char **name; | |
1081 | ||
2daf7fab | 1082 | if (!opts.uaccess) |
ea24213d PZ |
1083 | return; |
1084 | ||
1085 | for (name = uaccess_safe_builtin; *name; name++) { | |
1086 | func = find_symbol_by_name(file->elf, *name); | |
1087 | if (!func) | |
1088 | continue; | |
1089 | ||
e10cd8fe | 1090 | func->uaccess_safe = true; |
dcc914f4 JP |
1091 | } |
1092 | } | |
1093 | ||
258c7605 JP |
1094 | /* |
1095 | * FIXME: For now, just ignore any alternatives which add retpolines. This is | |
1096 | * a temporary hack, as it doesn't allow ORC to unwind from inside a retpoline. | |
1097 | * But it at least allows objtool to understand the control flow *around* the | |
1098 | * retpoline. | |
1099 | */ | |
ff05ab23 | 1100 | static int add_ignore_alternatives(struct objtool_file *file) |
258c7605 JP |
1101 | { |
1102 | struct section *sec; | |
f1974222 | 1103 | struct reloc *reloc; |
258c7605 JP |
1104 | struct instruction *insn; |
1105 | ||
ff05ab23 | 1106 | sec = find_section_by_name(file->elf, ".rela.discard.ignore_alts"); |
258c7605 JP |
1107 | if (!sec) |
1108 | return 0; | |
1109 | ||
f1974222 MH |
1110 | list_for_each_entry(reloc, &sec->reloc_list, list) { |
1111 | if (reloc->sym->type != STT_SECTION) { | |
258c7605 JP |
1112 | WARN("unexpected relocation symbol type in %s", sec->name); |
1113 | return -1; | |
1114 | } | |
1115 | ||
f1974222 | 1116 | insn = find_insn(file, reloc->sym->sec, reloc->addend); |
258c7605 | 1117 | if (!insn) { |
ff05ab23 | 1118 | WARN("bad .discard.ignore_alts entry"); |
258c7605 JP |
1119 | return -1; |
1120 | } | |
1121 | ||
1122 | insn->ignore_alts = true; | |
1123 | } | |
1124 | ||
1125 | return 0; | |
1126 | } | |
1127 | ||
530b4ddd PZ |
1128 | __weak bool arch_is_retpoline(struct symbol *sym) |
1129 | { | |
1130 | return false; | |
1131 | } | |
1132 | ||
d9e9d230 PZ |
1133 | __weak bool arch_is_rethunk(struct symbol *sym) |
1134 | { | |
1135 | return false; | |
1136 | } | |
1137 | ||
7bd2a600 PZ |
1138 | #define NEGATIVE_RELOC ((void *)-1L) |
1139 | ||
1140 | static struct reloc *insn_reloc(struct objtool_file *file, struct instruction *insn) | |
1141 | { | |
1142 | if (insn->reloc == NEGATIVE_RELOC) | |
1143 | return NULL; | |
1144 | ||
1145 | if (!insn->reloc) { | |
db2b0c5d PZ |
1146 | if (!file) |
1147 | return NULL; | |
1148 | ||
7bd2a600 PZ |
1149 | insn->reloc = find_reloc_by_dest_range(file->elf, insn->sec, |
1150 | insn->offset, insn->len); | |
1151 | if (!insn->reloc) { | |
1152 | insn->reloc = NEGATIVE_RELOC; | |
1153 | return NULL; | |
1154 | } | |
1155 | } | |
1156 | ||
1157 | return insn->reloc; | |
1158 | } | |
1159 | ||
f56dae88 PZ |
1160 | static void remove_insn_ops(struct instruction *insn) |
1161 | { | |
1162 | struct stack_op *op, *tmp; | |
1163 | ||
1164 | list_for_each_entry_safe(op, tmp, &insn->stack_ops, list) { | |
1165 | list_del(&op->list); | |
1166 | free(op); | |
1167 | } | |
1168 | } | |
1169 | ||
dd003ede PZ |
1170 | static void annotate_call_site(struct objtool_file *file, |
1171 | struct instruction *insn, bool sibling) | |
f56dae88 PZ |
1172 | { |
1173 | struct reloc *reloc = insn_reloc(file, insn); | |
dd003ede | 1174 | struct symbol *sym = insn->call_dest; |
f56dae88 | 1175 | |
dd003ede PZ |
1176 | if (!sym) |
1177 | sym = reloc->sym; | |
1178 | ||
1179 | /* | |
1180 | * Alternative replacement code is just template code which is | |
1181 | * sometimes copied to the original instruction. For now, don't | |
1182 | * annotate it. (In the future we might consider annotating the | |
1183 | * original instruction if/when it ever makes sense to do so.) | |
1184 | */ | |
1185 | if (!strcmp(insn->sec->name, ".altinstr_replacement")) | |
f56dae88 PZ |
1186 | return; |
1187 | ||
dd003ede PZ |
1188 | if (sym->static_call_tramp) { |
1189 | list_add_tail(&insn->call_node, &file->static_call_list); | |
1190 | return; | |
f56dae88 PZ |
1191 | } |
1192 | ||
134ab5bd PZ |
1193 | if (sym->retpoline_thunk) { |
1194 | list_add_tail(&insn->call_node, &file->retpoline_call_list); | |
1195 | return; | |
1196 | } | |
1197 | ||
f56dae88 | 1198 | /* |
05098119 ME |
1199 | * Many compilers cannot disable KCOV or sanitizer calls with a function |
1200 | * attribute so they need a little help, NOP out any such calls from | |
1201 | * noinstr text. | |
f56dae88 | 1202 | */ |
22102f45 | 1203 | if (opts.hack_noinstr && insn->sec->noinstr && sym->profiling_func) { |
f56dae88 PZ |
1204 | if (reloc) { |
1205 | reloc->type = R_NONE; | |
1206 | elf_write_reloc(file->elf, reloc); | |
1207 | } | |
1208 | ||
1209 | elf_write_insn(file->elf, insn->sec, | |
1210 | insn->offset, insn->len, | |
1211 | sibling ? arch_ret_insn(insn->len) | |
1212 | : arch_nop_insn(insn->len)); | |
1213 | ||
1214 | insn->type = sibling ? INSN_RETURN : INSN_NOP; | |
7a53f408 PZ |
1215 | |
1216 | if (sibling) { | |
1217 | /* | |
1218 | * We've replaced the tail-call JMP insn by two new | |
1219 | * insn: RET; INT3, except we only have a single struct | |
1220 | * insn here. Mark it retpoline_safe to avoid the SLS | |
1221 | * warning, instead of adding another insn. | |
1222 | */ | |
1223 | insn->retpoline_safe = true; | |
1224 | } | |
1225 | ||
dd003ede | 1226 | return; |
f56dae88 PZ |
1227 | } |
1228 | ||
2daf7fab | 1229 | if (opts.mcount && sym->fentry) { |
f56dae88 PZ |
1230 | if (sibling) |
1231 | WARN_FUNC("Tail call to __fentry__ !?!?", insn->sec, insn->offset); | |
1232 | ||
1233 | if (reloc) { | |
1234 | reloc->type = R_NONE; | |
1235 | elf_write_reloc(file->elf, reloc); | |
1236 | } | |
1237 | ||
1238 | elf_write_insn(file->elf, insn->sec, | |
1239 | insn->offset, insn->len, | |
1240 | arch_nop_insn(insn->len)); | |
1241 | ||
1242 | insn->type = INSN_NOP; | |
1243 | ||
c509331b | 1244 | list_add_tail(&insn->call_node, &file->mcount_loc_list); |
dd003ede | 1245 | return; |
f56dae88 | 1246 | } |
0e5b613b PZ |
1247 | |
1248 | if (!sibling && dead_end_function(file, sym)) | |
1249 | insn->dead_end = true; | |
dd003ede PZ |
1250 | } |
1251 | ||
1252 | static void add_call_dest(struct objtool_file *file, struct instruction *insn, | |
1253 | struct symbol *dest, bool sibling) | |
1254 | { | |
1255 | insn->call_dest = dest; | |
1256 | if (!dest) | |
1257 | return; | |
f56dae88 PZ |
1258 | |
1259 | /* | |
1260 | * Whatever stack impact regular CALLs have, should be undone | |
1261 | * by the RETURN of the called function. | |
1262 | * | |
1263 | * Annotated intra-function calls retain the stack_ops but | |
1264 | * are converted to JUMP, see read_intra_function_calls(). | |
1265 | */ | |
1266 | remove_insn_ops(insn); | |
dd003ede PZ |
1267 | |
1268 | annotate_call_site(file, insn, sibling); | |
f56dae88 PZ |
1269 | } |
1270 | ||
134ab5bd PZ |
1271 | static void add_retpoline_call(struct objtool_file *file, struct instruction *insn) |
1272 | { | |
1273 | /* | |
1274 | * Retpoline calls/jumps are really dynamic calls/jumps in disguise, | |
1275 | * so convert them accordingly. | |
1276 | */ | |
1277 | switch (insn->type) { | |
1278 | case INSN_CALL: | |
1279 | insn->type = INSN_CALL_DYNAMIC; | |
1280 | break; | |
1281 | case INSN_JUMP_UNCONDITIONAL: | |
1282 | insn->type = INSN_JUMP_DYNAMIC; | |
1283 | break; | |
1284 | case INSN_JUMP_CONDITIONAL: | |
1285 | insn->type = INSN_JUMP_DYNAMIC_CONDITIONAL; | |
1286 | break; | |
1287 | default: | |
1288 | return; | |
1289 | } | |
1290 | ||
1291 | insn->retpoline_safe = true; | |
1292 | ||
1293 | /* | |
1294 | * Whatever stack impact regular CALLs have, should be undone | |
1295 | * by the RETURN of the called function. | |
1296 | * | |
1297 | * Annotated intra-function calls retain the stack_ops but | |
1298 | * are converted to JUMP, see read_intra_function_calls(). | |
1299 | */ | |
1300 | remove_insn_ops(insn); | |
1301 | ||
1302 | annotate_call_site(file, insn, false); | |
1303 | } | |
08f87a93 | 1304 | |
a149180f | 1305 | static void add_return_call(struct objtool_file *file, struct instruction *insn, bool add) |
d9e9d230 PZ |
1306 | { |
1307 | /* | |
1308 | * Return thunk tail calls are really just returns in disguise, | |
1309 | * so convert them accordingly. | |
1310 | */ | |
1311 | insn->type = INSN_RETURN; | |
1312 | insn->retpoline_safe = true; | |
1313 | ||
a149180f PZ |
1314 | if (add) |
1315 | list_add_tail(&insn->call_node, &file->return_thunk_list); | |
d9e9d230 PZ |
1316 | } |
1317 | ||
08f87a93 PZ |
1318 | static bool same_function(struct instruction *insn1, struct instruction *insn2) |
1319 | { | |
1320 | return insn1->func->pfunc == insn2->func->pfunc; | |
1321 | } | |
1322 | ||
d139bca4 | 1323 | static bool is_first_func_insn(struct objtool_file *file, struct instruction *insn) |
08f87a93 | 1324 | { |
d139bca4 PZ |
1325 | if (insn->offset == insn->func->offset) |
1326 | return true; | |
1327 | ||
2daf7fab | 1328 | if (opts.ibt) { |
d139bca4 PZ |
1329 | struct instruction *prev = prev_insn_same_sym(file, insn); |
1330 | ||
1331 | if (prev && prev->type == INSN_ENDBR && | |
1332 | insn->offset == insn->func->offset + prev->len) | |
1333 | return true; | |
1334 | } | |
1335 | ||
1336 | return false; | |
08f87a93 PZ |
1337 | } |
1338 | ||
dcc914f4 JP |
1339 | /* |
1340 | * Find the destination instructions for all jumps. | |
1341 | */ | |
1342 | static int add_jump_destinations(struct objtool_file *file) | |
1343 | { | |
26ff6041 | 1344 | struct instruction *insn, *jump_dest; |
f1974222 | 1345 | struct reloc *reloc; |
dcc914f4 JP |
1346 | struct section *dest_sec; |
1347 | unsigned long dest_off; | |
1348 | ||
1349 | for_each_insn(file, insn) { | |
34c861e8 JP |
1350 | if (insn->jump_dest) { |
1351 | /* | |
1352 | * handle_group_alt() may have previously set | |
1353 | * 'jump_dest' for some alternatives. | |
1354 | */ | |
1355 | continue; | |
1356 | } | |
a2296140 | 1357 | if (!is_static_jump(insn)) |
dcc914f4 JP |
1358 | continue; |
1359 | ||
7bd2a600 | 1360 | reloc = insn_reloc(file, insn); |
f1974222 | 1361 | if (!reloc) { |
dcc914f4 | 1362 | dest_sec = insn->sec; |
bfb08f22 | 1363 | dest_off = arch_jump_destination(insn); |
f1974222 MH |
1364 | } else if (reloc->sym->type == STT_SECTION) { |
1365 | dest_sec = reloc->sym->sec; | |
1366 | dest_off = arch_dest_reloc_offset(reloc->addend); | |
1739c66e | 1367 | } else if (reloc->sym->retpoline_thunk) { |
134ab5bd | 1368 | add_retpoline_call(file, insn); |
39b73533 | 1369 | continue; |
d9e9d230 | 1370 | } else if (reloc->sym->return_thunk) { |
a149180f | 1371 | add_return_call(file, insn, true); |
d9e9d230 | 1372 | continue; |
ecf11ba4 | 1373 | } else if (insn->func) { |
26ff6041 JP |
1374 | /* |
1375 | * External sibling call or internal sibling call with | |
1376 | * STT_FUNC reloc. | |
1377 | */ | |
f56dae88 | 1378 | add_call_dest(file, insn, reloc->sym, true); |
dcc914f4 | 1379 | continue; |
ecf11ba4 JP |
1380 | } else if (reloc->sym->sec->idx) { |
1381 | dest_sec = reloc->sym->sec; | |
1382 | dest_off = reloc->sym->sym.st_value + | |
1383 | arch_dest_reloc_offset(reloc->addend); | |
1384 | } else { | |
1385 | /* non-func asm code jumping to another file */ | |
1386 | continue; | |
dcc914f4 JP |
1387 | } |
1388 | ||
26ff6041 JP |
1389 | jump_dest = find_insn(file, dest_sec, dest_off); |
1390 | if (!jump_dest) { | |
a149180f PZ |
1391 | struct symbol *sym = find_symbol_by_offset(dest_sec, dest_off); |
1392 | ||
1393 | /* | |
1394 | * This is a special case for zen_untrain_ret(). | |
1395 | * It jumps to __x86_return_thunk(), but objtool | |
1396 | * can't find the thunk's starting RET | |
1397 | * instruction, because the RET is also in the | |
1398 | * middle of another instruction. Objtool only | |
1399 | * knows about the outer instruction. | |
1400 | */ | |
1401 | if (sym && sym->return_thunk) { | |
1402 | add_return_call(file, insn, false); | |
1403 | continue; | |
1404 | } | |
1405 | ||
dcc914f4 JP |
1406 | WARN_FUNC("can't find jump dest instruction at %s+0x%lx", |
1407 | insn->sec, insn->offset, dest_sec->name, | |
1408 | dest_off); | |
1409 | return -1; | |
1410 | } | |
cd77849a JP |
1411 | |
1412 | /* | |
54262aa2 | 1413 | * Cross-function jump. |
cd77849a | 1414 | */ |
26ff6041 JP |
1415 | if (insn->func && jump_dest->func && |
1416 | insn->func != jump_dest->func) { | |
54262aa2 PZ |
1417 | |
1418 | /* | |
1419 | * For GCC 8+, create parent/child links for any cold | |
1420 | * subfunctions. This is _mostly_ redundant with a | |
1421 | * similar initialization in read_symbols(). | |
1422 | * | |
1423 | * If a function has aliases, we want the *first* such | |
1424 | * function in the symbol table to be the subfunction's | |
1425 | * parent. In that case we overwrite the | |
1426 | * initialization done in read_symbols(). | |
1427 | * | |
1428 | * However this code can't completely replace the | |
1429 | * read_symbols() code because this doesn't detect the | |
1430 | * case where the parent function's only reference to a | |
e7c2bc37 | 1431 | * subfunction is through a jump table. |
54262aa2 | 1432 | */ |
34ca59e1 | 1433 | if (!strstr(insn->func->name, ".cold") && |
26ff6041 JP |
1434 | strstr(jump_dest->func->name, ".cold")) { |
1435 | insn->func->cfunc = jump_dest->func; | |
1436 | jump_dest->func->pfunc = insn->func; | |
1437 | ||
1438 | } else if (!same_function(insn, jump_dest) && | |
1439 | is_first_func_insn(file, jump_dest)) { | |
1440 | /* | |
1441 | * Internal sibling call without reloc or with | |
1442 | * STT_SECTION reloc. | |
1443 | */ | |
1444 | add_call_dest(file, insn, jump_dest->func, true); | |
1445 | continue; | |
54262aa2 | 1446 | } |
cd77849a | 1447 | } |
26ff6041 JP |
1448 | |
1449 | insn->jump_dest = jump_dest; | |
dcc914f4 JP |
1450 | } |
1451 | ||
1452 | return 0; | |
1453 | } | |
1454 | ||
2b232a22 JT |
1455 | static struct symbol *find_call_destination(struct section *sec, unsigned long offset) |
1456 | { | |
1457 | struct symbol *call_dest; | |
1458 | ||
1459 | call_dest = find_func_by_offset(sec, offset); | |
1460 | if (!call_dest) | |
1461 | call_dest = find_symbol_by_offset(sec, offset); | |
1462 | ||
1463 | return call_dest; | |
1464 | } | |
1465 | ||
dcc914f4 JP |
1466 | /* |
1467 | * Find the destination instructions for all calls. | |
1468 | */ | |
1469 | static int add_call_destinations(struct objtool_file *file) | |
1470 | { | |
1471 | struct instruction *insn; | |
1472 | unsigned long dest_off; | |
f56dae88 | 1473 | struct symbol *dest; |
f1974222 | 1474 | struct reloc *reloc; |
dcc914f4 JP |
1475 | |
1476 | for_each_insn(file, insn) { | |
1477 | if (insn->type != INSN_CALL) | |
1478 | continue; | |
1479 | ||
7bd2a600 | 1480 | reloc = insn_reloc(file, insn); |
f1974222 | 1481 | if (!reloc) { |
bfb08f22 | 1482 | dest_off = arch_jump_destination(insn); |
f56dae88 PZ |
1483 | dest = find_call_destination(insn->sec, dest_off); |
1484 | ||
1485 | add_call_dest(file, insn, dest, false); | |
a845c7cf | 1486 | |
7acfe531 JP |
1487 | if (insn->ignore) |
1488 | continue; | |
1489 | ||
1490 | if (!insn->call_dest) { | |
8aa8eb2a | 1491 | WARN_FUNC("unannotated intra-function call", insn->sec, insn->offset); |
dcc914f4 JP |
1492 | return -1; |
1493 | } | |
a845c7cf | 1494 | |
7acfe531 JP |
1495 | if (insn->func && insn->call_dest->type != STT_FUNC) { |
1496 | WARN_FUNC("unsupported call to non-function", | |
1497 | insn->sec, insn->offset); | |
1498 | return -1; | |
1499 | } | |
1500 | ||
f1974222 MH |
1501 | } else if (reloc->sym->type == STT_SECTION) { |
1502 | dest_off = arch_dest_reloc_offset(reloc->addend); | |
f56dae88 PZ |
1503 | dest = find_call_destination(reloc->sym->sec, dest_off); |
1504 | if (!dest) { | |
bfb08f22 | 1505 | WARN_FUNC("can't find call dest symbol at %s+0x%lx", |
dcc914f4 | 1506 | insn->sec, insn->offset, |
f1974222 | 1507 | reloc->sym->sec->name, |
bfb08f22 | 1508 | dest_off); |
dcc914f4 JP |
1509 | return -1; |
1510 | } | |
bcb1b6ff | 1511 | |
f56dae88 PZ |
1512 | add_call_dest(file, insn, dest, false); |
1513 | ||
1739c66e | 1514 | } else if (reloc->sym->retpoline_thunk) { |
134ab5bd | 1515 | add_retpoline_call(file, insn); |
bcb1b6ff | 1516 | |
dcc914f4 | 1517 | } else |
f56dae88 | 1518 | add_call_dest(file, insn, reloc->sym, false); |
dcc914f4 JP |
1519 | } |
1520 | ||
1521 | return 0; | |
1522 | } | |
1523 | ||
1524 | /* | |
c9c324dc JP |
1525 | * The .alternatives section requires some extra special care over and above |
1526 | * other special sections because alternatives are patched in place. | |
dcc914f4 JP |
1527 | */ |
1528 | static int handle_group_alt(struct objtool_file *file, | |
1529 | struct special_alt *special_alt, | |
1530 | struct instruction *orig_insn, | |
1531 | struct instruction **new_insn) | |
1532 | { | |
c9c324dc | 1533 | struct instruction *last_orig_insn, *last_new_insn = NULL, *insn, *nop = NULL; |
b23cc71c | 1534 | struct alt_group *orig_alt_group, *new_alt_group; |
dcc914f4 JP |
1535 | unsigned long dest_off; |
1536 | ||
b23cc71c JP |
1537 | |
1538 | orig_alt_group = malloc(sizeof(*orig_alt_group)); | |
1539 | if (!orig_alt_group) { | |
1540 | WARN("malloc failed"); | |
1541 | return -1; | |
1542 | } | |
c9c324dc JP |
1543 | orig_alt_group->cfi = calloc(special_alt->orig_len, |
1544 | sizeof(struct cfi_state *)); | |
1545 | if (!orig_alt_group->cfi) { | |
1546 | WARN("calloc failed"); | |
1547 | return -1; | |
1548 | } | |
1549 | ||
dcc914f4 JP |
1550 | last_orig_insn = NULL; |
1551 | insn = orig_insn; | |
1552 | sec_for_each_insn_from(file, insn) { | |
1553 | if (insn->offset >= special_alt->orig_off + special_alt->orig_len) | |
1554 | break; | |
1555 | ||
b23cc71c | 1556 | insn->alt_group = orig_alt_group; |
dcc914f4 JP |
1557 | last_orig_insn = insn; |
1558 | } | |
b23cc71c JP |
1559 | orig_alt_group->orig_group = NULL; |
1560 | orig_alt_group->first_insn = orig_insn; | |
1561 | orig_alt_group->last_insn = last_orig_insn; | |
dcc914f4 | 1562 | |
17bc3391 | 1563 | |
c9c324dc JP |
1564 | new_alt_group = malloc(sizeof(*new_alt_group)); |
1565 | if (!new_alt_group) { | |
1566 | WARN("malloc failed"); | |
1567 | return -1; | |
dcc914f4 | 1568 | } |
dcc914f4 | 1569 | |
c9c324dc JP |
1570 | if (special_alt->new_len < special_alt->orig_len) { |
1571 | /* | |
1572 | * Insert a fake nop at the end to make the replacement | |
1573 | * alt_group the same size as the original. This is needed to | |
1574 | * allow propagate_alt_cfi() to do its magic. When the last | |
1575 | * instruction affects the stack, the instruction after it (the | |
1576 | * nop) will propagate the new state to the shared CFI array. | |
1577 | */ | |
1578 | nop = malloc(sizeof(*nop)); | |
1579 | if (!nop) { | |
1580 | WARN("malloc failed"); | |
17bc3391 JP |
1581 | return -1; |
1582 | } | |
c9c324dc JP |
1583 | memset(nop, 0, sizeof(*nop)); |
1584 | INIT_LIST_HEAD(&nop->alts); | |
1585 | INIT_LIST_HEAD(&nop->stack_ops); | |
c9c324dc JP |
1586 | |
1587 | nop->sec = special_alt->new_sec; | |
1588 | nop->offset = special_alt->new_off + special_alt->new_len; | |
1589 | nop->len = special_alt->orig_len - special_alt->new_len; | |
1590 | nop->type = INSN_NOP; | |
1591 | nop->func = orig_insn->func; | |
1592 | nop->alt_group = new_alt_group; | |
1593 | nop->ignore = orig_insn->ignore_alts; | |
dcc914f4 | 1594 | } |
17bc3391 | 1595 | |
c9c324dc JP |
1596 | if (!special_alt->new_len) { |
1597 | *new_insn = nop; | |
1598 | goto end; | |
dcc914f4 JP |
1599 | } |
1600 | ||
dcc914f4 JP |
1601 | insn = *new_insn; |
1602 | sec_for_each_insn_from(file, insn) { | |
45245f51 JT |
1603 | struct reloc *alt_reloc; |
1604 | ||
dcc914f4 JP |
1605 | if (insn->offset >= special_alt->new_off + special_alt->new_len) |
1606 | break; | |
1607 | ||
1608 | last_new_insn = insn; | |
1609 | ||
a845c7cf | 1610 | insn->ignore = orig_insn->ignore_alts; |
a4d09dde | 1611 | insn->func = orig_insn->func; |
b23cc71c | 1612 | insn->alt_group = new_alt_group; |
a845c7cf | 1613 | |
dc419723 JP |
1614 | /* |
1615 | * Since alternative replacement code is copy/pasted by the | |
1616 | * kernel after applying relocations, generally such code can't | |
1617 | * have relative-address relocation references to outside the | |
1618 | * .altinstr_replacement section, unless the arch's | |
1619 | * alternatives code can adjust the relative offsets | |
1620 | * accordingly. | |
dc419723 | 1621 | */ |
7bd2a600 | 1622 | alt_reloc = insn_reloc(file, insn); |
45245f51 JT |
1623 | if (alt_reloc && |
1624 | !arch_support_alt_relocation(special_alt, insn, alt_reloc)) { | |
dc419723 JP |
1625 | |
1626 | WARN_FUNC("unsupported relocation in alternatives section", | |
1627 | insn->sec, insn->offset); | |
1628 | return -1; | |
1629 | } | |
1630 | ||
a2296140 | 1631 | if (!is_static_jump(insn)) |
dcc914f4 JP |
1632 | continue; |
1633 | ||
1634 | if (!insn->immediate) | |
1635 | continue; | |
1636 | ||
bfb08f22 | 1637 | dest_off = arch_jump_destination(insn); |
34c861e8 | 1638 | if (dest_off == special_alt->new_off + special_alt->new_len) { |
c9c324dc | 1639 | insn->jump_dest = next_insn_same_sec(file, last_orig_insn); |
34c861e8 JP |
1640 | if (!insn->jump_dest) { |
1641 | WARN_FUNC("can't find alternative jump destination", | |
1642 | insn->sec, insn->offset); | |
1643 | return -1; | |
1644 | } | |
dcc914f4 JP |
1645 | } |
1646 | } | |
1647 | ||
1648 | if (!last_new_insn) { | |
1649 | WARN_FUNC("can't find last new alternative instruction", | |
1650 | special_alt->new_sec, special_alt->new_off); | |
1651 | return -1; | |
1652 | } | |
1653 | ||
c9c324dc JP |
1654 | if (nop) |
1655 | list_add(&nop->list, &last_new_insn->list); | |
1656 | end: | |
b23cc71c JP |
1657 | new_alt_group->orig_group = orig_alt_group; |
1658 | new_alt_group->first_insn = *new_insn; | |
c9c324dc JP |
1659 | new_alt_group->last_insn = nop ? : last_new_insn; |
1660 | new_alt_group->cfi = orig_alt_group->cfi; | |
dcc914f4 JP |
1661 | return 0; |
1662 | } | |
1663 | ||
1664 | /* | |
1665 | * A jump table entry can either convert a nop to a jump or a jump to a nop. | |
1666 | * If the original instruction is a jump, make the alt entry an effective nop | |
1667 | * by just skipping the original instruction. | |
1668 | */ | |
1669 | static int handle_jump_alt(struct objtool_file *file, | |
1670 | struct special_alt *special_alt, | |
1671 | struct instruction *orig_insn, | |
1672 | struct instruction **new_insn) | |
1673 | { | |
48001d26 PZ |
1674 | if (orig_insn->type != INSN_JUMP_UNCONDITIONAL && |
1675 | orig_insn->type != INSN_NOP) { | |
e2d9494b | 1676 | |
dcc914f4 JP |
1677 | WARN_FUNC("unsupported instruction at jump label", |
1678 | orig_insn->sec, orig_insn->offset); | |
1679 | return -1; | |
1680 | } | |
1681 | ||
4ab7674f | 1682 | if (opts.hack_jump_label && special_alt->key_addend & 2) { |
6d37b83c PZ |
1683 | struct reloc *reloc = insn_reloc(file, orig_insn); |
1684 | ||
1685 | if (reloc) { | |
1686 | reloc->type = R_NONE; | |
1687 | elf_write_reloc(file->elf, reloc); | |
1688 | } | |
1689 | elf_write_insn(file->elf, orig_insn->sec, | |
1690 | orig_insn->offset, orig_insn->len, | |
1691 | arch_nop_insn(orig_insn->len)); | |
1692 | orig_insn->type = INSN_NOP; | |
48001d26 PZ |
1693 | } |
1694 | ||
1695 | if (orig_insn->type == INSN_NOP) { | |
1696 | if (orig_insn->len == 2) | |
1697 | file->jl_nop_short++; | |
1698 | else | |
1699 | file->jl_nop_long++; | |
1700 | ||
1701 | return 0; | |
6d37b83c PZ |
1702 | } |
1703 | ||
e2d9494b PZ |
1704 | if (orig_insn->len == 2) |
1705 | file->jl_short++; | |
1706 | else | |
1707 | file->jl_long++; | |
1708 | ||
dcc914f4 JP |
1709 | *new_insn = list_next_entry(orig_insn, list); |
1710 | return 0; | |
1711 | } | |
1712 | ||
1713 | /* | |
1714 | * Read all the special sections which have alternate instructions which can be | |
1715 | * patched in or redirected to at runtime. Each instruction having alternate | |
1716 | * instruction(s) has them added to its insn->alts list, which will be | |
1717 | * traversed in validate_branch(). | |
1718 | */ | |
1719 | static int add_special_section_alts(struct objtool_file *file) | |
1720 | { | |
1721 | struct list_head special_alts; | |
1722 | struct instruction *orig_insn, *new_insn; | |
1723 | struct special_alt *special_alt, *tmp; | |
1724 | struct alternative *alt; | |
1725 | int ret; | |
1726 | ||
1727 | ret = special_get_alts(file->elf, &special_alts); | |
1728 | if (ret) | |
1729 | return ret; | |
1730 | ||
1731 | list_for_each_entry_safe(special_alt, tmp, &special_alts, list) { | |
dcc914f4 JP |
1732 | |
1733 | orig_insn = find_insn(file, special_alt->orig_sec, | |
1734 | special_alt->orig_off); | |
1735 | if (!orig_insn) { | |
1736 | WARN_FUNC("special: can't find orig instruction", | |
1737 | special_alt->orig_sec, special_alt->orig_off); | |
1738 | ret = -1; | |
1739 | goto out; | |
1740 | } | |
1741 | ||
1742 | new_insn = NULL; | |
1743 | if (!special_alt->group || special_alt->new_len) { | |
1744 | new_insn = find_insn(file, special_alt->new_sec, | |
1745 | special_alt->new_off); | |
1746 | if (!new_insn) { | |
1747 | WARN_FUNC("special: can't find new instruction", | |
1748 | special_alt->new_sec, | |
1749 | special_alt->new_off); | |
1750 | ret = -1; | |
1751 | goto out; | |
1752 | } | |
1753 | } | |
1754 | ||
1755 | if (special_alt->group) { | |
7170cf47 JT |
1756 | if (!special_alt->orig_len) { |
1757 | WARN_FUNC("empty alternative entry", | |
1758 | orig_insn->sec, orig_insn->offset); | |
1759 | continue; | |
1760 | } | |
1761 | ||
dcc914f4 JP |
1762 | ret = handle_group_alt(file, special_alt, orig_insn, |
1763 | &new_insn); | |
1764 | if (ret) | |
1765 | goto out; | |
1766 | } else if (special_alt->jump_or_nop) { | |
1767 | ret = handle_jump_alt(file, special_alt, orig_insn, | |
1768 | &new_insn); | |
1769 | if (ret) | |
1770 | goto out; | |
1771 | } | |
1772 | ||
258c7605 JP |
1773 | alt = malloc(sizeof(*alt)); |
1774 | if (!alt) { | |
1775 | WARN("malloc failed"); | |
1776 | ret = -1; | |
1777 | goto out; | |
1778 | } | |
1779 | ||
dcc914f4 | 1780 | alt->insn = new_insn; |
764eef4b | 1781 | alt->skip_orig = special_alt->skip_orig; |
ea24213d | 1782 | orig_insn->ignore_alts |= special_alt->skip_alt; |
dcc914f4 JP |
1783 | list_add_tail(&alt->list, &orig_insn->alts); |
1784 | ||
1785 | list_del(&special_alt->list); | |
1786 | free(special_alt); | |
1787 | } | |
1788 | ||
2daf7fab | 1789 | if (opts.stats) { |
e2d9494b PZ |
1790 | printf("jl\\\tNOP\tJMP\n"); |
1791 | printf("short:\t%ld\t%ld\n", file->jl_nop_short, file->jl_short); | |
1792 | printf("long:\t%ld\t%ld\n", file->jl_nop_long, file->jl_long); | |
1793 | } | |
1794 | ||
dcc914f4 JP |
1795 | out: |
1796 | return ret; | |
1797 | } | |
1798 | ||
e7c2bc37 | 1799 | static int add_jump_table(struct objtool_file *file, struct instruction *insn, |
f1974222 | 1800 | struct reloc *table) |
dcc914f4 | 1801 | { |
f1974222 | 1802 | struct reloc *reloc = table; |
e7c2bc37 | 1803 | struct instruction *dest_insn; |
dcc914f4 | 1804 | struct alternative *alt; |
fd35c88b JP |
1805 | struct symbol *pfunc = insn->func->pfunc; |
1806 | unsigned int prev_offset = 0; | |
dcc914f4 | 1807 | |
e7c2bc37 | 1808 | /* |
f1974222 | 1809 | * Each @reloc is a switch table relocation which points to the target |
e7c2bc37 JP |
1810 | * instruction. |
1811 | */ | |
f1974222 | 1812 | list_for_each_entry_from(reloc, &table->sec->reloc_list, list) { |
bd98c813 JH |
1813 | |
1814 | /* Check for the end of the table: */ | |
f1974222 | 1815 | if (reloc != table && reloc->jump_table_start) |
dcc914f4 JP |
1816 | break; |
1817 | ||
e7c2bc37 | 1818 | /* Make sure the table entries are consecutive: */ |
f1974222 | 1819 | if (prev_offset && reloc->offset != prev_offset + 8) |
fd35c88b JP |
1820 | break; |
1821 | ||
1822 | /* Detect function pointers from contiguous objects: */ | |
f1974222 MH |
1823 | if (reloc->sym->sec == pfunc->sec && |
1824 | reloc->addend == pfunc->offset) | |
fd35c88b JP |
1825 | break; |
1826 | ||
f1974222 | 1827 | dest_insn = find_insn(file, reloc->sym->sec, reloc->addend); |
e7c2bc37 | 1828 | if (!dest_insn) |
dcc914f4 JP |
1829 | break; |
1830 | ||
e7c2bc37 | 1831 | /* Make sure the destination is in the same function: */ |
e65050b9 | 1832 | if (!dest_insn->func || dest_insn->func->pfunc != pfunc) |
13810435 | 1833 | break; |
dcc914f4 JP |
1834 | |
1835 | alt = malloc(sizeof(*alt)); | |
1836 | if (!alt) { | |
1837 | WARN("malloc failed"); | |
1838 | return -1; | |
1839 | } | |
1840 | ||
e7c2bc37 | 1841 | alt->insn = dest_insn; |
dcc914f4 | 1842 | list_add_tail(&alt->list, &insn->alts); |
f1974222 | 1843 | prev_offset = reloc->offset; |
fd35c88b JP |
1844 | } |
1845 | ||
1846 | if (!prev_offset) { | |
1847 | WARN_FUNC("can't find switch jump table", | |
1848 | insn->sec, insn->offset); | |
1849 | return -1; | |
dcc914f4 JP |
1850 | } |
1851 | ||
1852 | return 0; | |
1853 | } | |
1854 | ||
1855 | /* | |
d871f7b5 RG |
1856 | * find_jump_table() - Given a dynamic jump, find the switch jump table |
1857 | * associated with it. | |
dcc914f4 | 1858 | */ |
f1974222 | 1859 | static struct reloc *find_jump_table(struct objtool_file *file, |
dcc914f4 JP |
1860 | struct symbol *func, |
1861 | struct instruction *insn) | |
1862 | { | |
d871f7b5 | 1863 | struct reloc *table_reloc; |
113d4bc9 | 1864 | struct instruction *dest_insn, *orig_insn = insn; |
dcc914f4 | 1865 | |
99ce7962 PZ |
1866 | /* |
1867 | * Backward search using the @first_jump_src links, these help avoid | |
1868 | * much of the 'in between' code. Which avoids us getting confused by | |
1869 | * it. | |
1870 | */ | |
7dec80cc | 1871 | for (; |
1119d265 JP |
1872 | insn && insn->func && insn->func->pfunc == func; |
1873 | insn = insn->first_jump_src ?: prev_insn_same_sym(file, insn)) { | |
99ce7962 | 1874 | |
7dec80cc | 1875 | if (insn != orig_insn && insn->type == INSN_JUMP_DYNAMIC) |
dcc914f4 JP |
1876 | break; |
1877 | ||
1878 | /* allow small jumps within the range */ | |
1879 | if (insn->type == INSN_JUMP_UNCONDITIONAL && | |
1880 | insn->jump_dest && | |
1881 | (insn->jump_dest->offset <= insn->offset || | |
1882 | insn->jump_dest->offset > orig_insn->offset)) | |
1883 | break; | |
1884 | ||
d871f7b5 | 1885 | table_reloc = arch_find_switch_table(file, insn); |
f1974222 | 1886 | if (!table_reloc) |
e7c2bc37 | 1887 | continue; |
f1974222 | 1888 | dest_insn = find_insn(file, table_reloc->sym->sec, table_reloc->addend); |
113d4bc9 JP |
1889 | if (!dest_insn || !dest_insn->func || dest_insn->func->pfunc != func) |
1890 | continue; | |
7dec80cc | 1891 | |
f1974222 | 1892 | return table_reloc; |
dcc914f4 JP |
1893 | } |
1894 | ||
1895 | return NULL; | |
1896 | } | |
1897 | ||
bd98c813 JH |
1898 | /* |
1899 | * First pass: Mark the head of each jump table so that in the next pass, | |
1900 | * we know when a given jump table ends and the next one starts. | |
1901 | */ | |
1902 | static void mark_func_jump_tables(struct objtool_file *file, | |
1903 | struct symbol *func) | |
dcc914f4 | 1904 | { |
bd98c813 | 1905 | struct instruction *insn, *last = NULL; |
f1974222 | 1906 | struct reloc *reloc; |
dcc914f4 | 1907 | |
f0f70adb | 1908 | func_for_each_insn(file, func, insn) { |
99ce7962 PZ |
1909 | if (!last) |
1910 | last = insn; | |
1911 | ||
1912 | /* | |
1913 | * Store back-pointers for unconditional forward jumps such | |
e7c2bc37 | 1914 | * that find_jump_table() can back-track using those and |
99ce7962 PZ |
1915 | * avoid some potentially confusing code. |
1916 | */ | |
1917 | if (insn->type == INSN_JUMP_UNCONDITIONAL && insn->jump_dest && | |
1918 | insn->offset > last->offset && | |
1919 | insn->jump_dest->offset > insn->offset && | |
1920 | !insn->jump_dest->first_jump_src) { | |
1921 | ||
1922 | insn->jump_dest->first_jump_src = insn; | |
1923 | last = insn->jump_dest; | |
1924 | } | |
1925 | ||
dcc914f4 JP |
1926 | if (insn->type != INSN_JUMP_DYNAMIC) |
1927 | continue; | |
1928 | ||
f1974222 MH |
1929 | reloc = find_jump_table(file, func, insn); |
1930 | if (reloc) { | |
1931 | reloc->jump_table_start = true; | |
1932 | insn->jump_table = reloc; | |
dcc914f4 | 1933 | } |
dcc914f4 | 1934 | } |
bd98c813 JH |
1935 | } |
1936 | ||
1937 | static int add_func_jump_tables(struct objtool_file *file, | |
1938 | struct symbol *func) | |
1939 | { | |
1940 | struct instruction *insn; | |
1941 | int ret; | |
1942 | ||
f0f70adb | 1943 | func_for_each_insn(file, func, insn) { |
bd98c813 JH |
1944 | if (!insn->jump_table) |
1945 | continue; | |
dcc914f4 | 1946 | |
bd98c813 | 1947 | ret = add_jump_table(file, insn, insn->jump_table); |
dcc914f4 JP |
1948 | if (ret) |
1949 | return ret; | |
1950 | } | |
1951 | ||
1952 | return 0; | |
1953 | } | |
1954 | ||
1955 | /* | |
1956 | * For some switch statements, gcc generates a jump table in the .rodata | |
1957 | * section which contains a list of addresses within the function to jump to. | |
1958 | * This finds these jump tables and adds them to the insn->alts lists. | |
1959 | */ | |
e7c2bc37 | 1960 | static int add_jump_table_alts(struct objtool_file *file) |
dcc914f4 JP |
1961 | { |
1962 | struct section *sec; | |
1963 | struct symbol *func; | |
1964 | int ret; | |
1965 | ||
4a60aa05 | 1966 | if (!file->rodata) |
dcc914f4 JP |
1967 | return 0; |
1968 | ||
baa41469 | 1969 | for_each_sec(file, sec) { |
dcc914f4 JP |
1970 | list_for_each_entry(func, &sec->symbol_list, list) { |
1971 | if (func->type != STT_FUNC) | |
1972 | continue; | |
1973 | ||
bd98c813 | 1974 | mark_func_jump_tables(file, func); |
e7c2bc37 | 1975 | ret = add_func_jump_tables(file, func); |
dcc914f4 JP |
1976 | if (ret) |
1977 | return ret; | |
1978 | } | |
1979 | } | |
1980 | ||
1981 | return 0; | |
1982 | } | |
1983 | ||
b735bd3e JP |
1984 | static void set_func_state(struct cfi_state *state) |
1985 | { | |
1986 | state->cfa = initial_func_cfi.cfa; | |
1987 | memcpy(&state->regs, &initial_func_cfi.regs, | |
1988 | CFI_NUM_REGS * sizeof(struct cfi_reg)); | |
1989 | state->stack_size = initial_func_cfi.cfa.offset; | |
1990 | } | |
1991 | ||
39358a03 JP |
1992 | static int read_unwind_hints(struct objtool_file *file) |
1993 | { | |
8b946cc3 | 1994 | struct cfi_state cfi = init_cfi; |
f1974222 | 1995 | struct section *sec, *relocsec; |
39358a03 JP |
1996 | struct unwind_hint *hint; |
1997 | struct instruction *insn; | |
8b946cc3 | 1998 | struct reloc *reloc; |
39358a03 JP |
1999 | int i; |
2000 | ||
2001 | sec = find_section_by_name(file->elf, ".discard.unwind_hints"); | |
2002 | if (!sec) | |
2003 | return 0; | |
2004 | ||
f1974222 MH |
2005 | relocsec = sec->reloc; |
2006 | if (!relocsec) { | |
39358a03 JP |
2007 | WARN("missing .rela.discard.unwind_hints section"); |
2008 | return -1; | |
2009 | } | |
2010 | ||
fe255fe6 | 2011 | if (sec->sh.sh_size % sizeof(struct unwind_hint)) { |
39358a03 JP |
2012 | WARN("struct unwind_hint size mismatch"); |
2013 | return -1; | |
2014 | } | |
2015 | ||
2016 | file->hints = true; | |
2017 | ||
fe255fe6 | 2018 | for (i = 0; i < sec->sh.sh_size / sizeof(struct unwind_hint); i++) { |
39358a03 JP |
2019 | hint = (struct unwind_hint *)sec->data->d_buf + i; |
2020 | ||
f1974222 MH |
2021 | reloc = find_reloc_by_dest(file->elf, sec, i * sizeof(*hint)); |
2022 | if (!reloc) { | |
2023 | WARN("can't find reloc for unwind_hints[%d]", i); | |
39358a03 JP |
2024 | return -1; |
2025 | } | |
2026 | ||
f1974222 | 2027 | insn = find_insn(file, reloc->sym->sec, reloc->addend); |
39358a03 JP |
2028 | if (!insn) { |
2029 | WARN("can't find insn for unwind_hints[%d]", i); | |
2030 | return -1; | |
2031 | } | |
2032 | ||
b735bd3e | 2033 | insn->hint = true; |
39358a03 | 2034 | |
a09a6e23 | 2035 | if (hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) { |
08f87a93 PZ |
2036 | struct symbol *sym = find_symbol_by_offset(insn->sec, insn->offset); |
2037 | ||
a09a6e23 PZ |
2038 | if (sym && sym->bind == STB_GLOBAL) { |
2039 | if (opts.ibt && insn->type != INSN_ENDBR && !insn->noendbr) { | |
2040 | WARN_FUNC("UNWIND_HINT_IRET_REGS without ENDBR", | |
2041 | insn->sec, insn->offset); | |
2042 | } | |
2043 | ||
2044 | insn->entry = 1; | |
08f87a93 PZ |
2045 | } |
2046 | } | |
2047 | ||
a09a6e23 PZ |
2048 | if (hint->type == UNWIND_HINT_TYPE_ENTRY) { |
2049 | hint->type = UNWIND_HINT_TYPE_CALL; | |
2050 | insn->entry = 1; | |
2051 | } | |
2052 | ||
b735bd3e | 2053 | if (hint->type == UNWIND_HINT_TYPE_FUNC) { |
8b946cc3 | 2054 | insn->cfi = &func_cfi; |
39358a03 JP |
2055 | continue; |
2056 | } | |
2057 | ||
8b946cc3 PZ |
2058 | if (insn->cfi) |
2059 | cfi = *(insn->cfi); | |
2060 | ||
2061 | if (arch_decode_hint_reg(hint->sp_reg, &cfi.cfa.base)) { | |
39358a03 JP |
2062 | WARN_FUNC("unsupported unwind_hint sp base reg %d", |
2063 | insn->sec, insn->offset, hint->sp_reg); | |
2064 | return -1; | |
2065 | } | |
2066 | ||
8b946cc3 PZ |
2067 | cfi.cfa.offset = bswap_if_needed(hint->sp_offset); |
2068 | cfi.type = hint->type; | |
2069 | cfi.end = hint->end; | |
2070 | ||
2071 | insn->cfi = cfi_hash_find_or_add(&cfi); | |
39358a03 JP |
2072 | } |
2073 | ||
2074 | return 0; | |
2075 | } | |
2076 | ||
96db4a98 PZ |
2077 | static int read_noendbr_hints(struct objtool_file *file) |
2078 | { | |
2079 | struct section *sec; | |
2080 | struct instruction *insn; | |
2081 | struct reloc *reloc; | |
2082 | ||
2083 | sec = find_section_by_name(file->elf, ".rela.discard.noendbr"); | |
2084 | if (!sec) | |
2085 | return 0; | |
2086 | ||
2087 | list_for_each_entry(reloc, &sec->reloc_list, list) { | |
2088 | insn = find_insn(file, reloc->sym->sec, reloc->sym->offset + reloc->addend); | |
2089 | if (!insn) { | |
2090 | WARN("bad .discard.noendbr entry"); | |
2091 | return -1; | |
2092 | } | |
2093 | ||
08f87a93 PZ |
2094 | if (insn->type == INSN_ENDBR) |
2095 | WARN_FUNC("ANNOTATE_NOENDBR on ENDBR", insn->sec, insn->offset); | |
2096 | ||
96db4a98 PZ |
2097 | insn->noendbr = 1; |
2098 | } | |
2099 | ||
2100 | return 0; | |
2101 | } | |
2102 | ||
b5bc2231 PZ |
2103 | static int read_retpoline_hints(struct objtool_file *file) |
2104 | { | |
63474dc4 | 2105 | struct section *sec; |
b5bc2231 | 2106 | struct instruction *insn; |
f1974222 | 2107 | struct reloc *reloc; |
b5bc2231 | 2108 | |
63474dc4 | 2109 | sec = find_section_by_name(file->elf, ".rela.discard.retpoline_safe"); |
b5bc2231 PZ |
2110 | if (!sec) |
2111 | return 0; | |
2112 | ||
f1974222 MH |
2113 | list_for_each_entry(reloc, &sec->reloc_list, list) { |
2114 | if (reloc->sym->type != STT_SECTION) { | |
63474dc4 | 2115 | WARN("unexpected relocation symbol type in %s", sec->name); |
b5bc2231 PZ |
2116 | return -1; |
2117 | } | |
2118 | ||
f1974222 | 2119 | insn = find_insn(file, reloc->sym->sec, reloc->addend); |
b5bc2231 | 2120 | if (!insn) { |
63474dc4 | 2121 | WARN("bad .discard.retpoline_safe entry"); |
b5bc2231 PZ |
2122 | return -1; |
2123 | } | |
2124 | ||
2125 | if (insn->type != INSN_JUMP_DYNAMIC && | |
9bb2ec60 | 2126 | insn->type != INSN_CALL_DYNAMIC && |
a09a6e23 PZ |
2127 | insn->type != INSN_RETURN && |
2128 | insn->type != INSN_NOP) { | |
2129 | WARN_FUNC("retpoline_safe hint not an indirect jump/call/ret/nop", | |
b5bc2231 PZ |
2130 | insn->sec, insn->offset); |
2131 | return -1; | |
2132 | } | |
2133 | ||
2134 | insn->retpoline_safe = true; | |
2135 | } | |
2136 | ||
2137 | return 0; | |
2138 | } | |
2139 | ||
c4a33939 PZ |
2140 | static int read_instr_hints(struct objtool_file *file) |
2141 | { | |
2142 | struct section *sec; | |
2143 | struct instruction *insn; | |
f1974222 | 2144 | struct reloc *reloc; |
c4a33939 PZ |
2145 | |
2146 | sec = find_section_by_name(file->elf, ".rela.discard.instr_end"); | |
2147 | if (!sec) | |
2148 | return 0; | |
2149 | ||
f1974222 MH |
2150 | list_for_each_entry(reloc, &sec->reloc_list, list) { |
2151 | if (reloc->sym->type != STT_SECTION) { | |
c4a33939 PZ |
2152 | WARN("unexpected relocation symbol type in %s", sec->name); |
2153 | return -1; | |
2154 | } | |
2155 | ||
f1974222 | 2156 | insn = find_insn(file, reloc->sym->sec, reloc->addend); |
c4a33939 PZ |
2157 | if (!insn) { |
2158 | WARN("bad .discard.instr_end entry"); | |
2159 | return -1; | |
2160 | } | |
2161 | ||
2162 | insn->instr--; | |
2163 | } | |
2164 | ||
2165 | sec = find_section_by_name(file->elf, ".rela.discard.instr_begin"); | |
2166 | if (!sec) | |
2167 | return 0; | |
2168 | ||
f1974222 MH |
2169 | list_for_each_entry(reloc, &sec->reloc_list, list) { |
2170 | if (reloc->sym->type != STT_SECTION) { | |
c4a33939 PZ |
2171 | WARN("unexpected relocation symbol type in %s", sec->name); |
2172 | return -1; | |
2173 | } | |
2174 | ||
f1974222 | 2175 | insn = find_insn(file, reloc->sym->sec, reloc->addend); |
c4a33939 PZ |
2176 | if (!insn) { |
2177 | WARN("bad .discard.instr_begin entry"); | |
2178 | return -1; | |
2179 | } | |
2180 | ||
2181 | insn->instr++; | |
2182 | } | |
2183 | ||
2184 | return 0; | |
2185 | } | |
2186 | ||
8aa8eb2a AC |
2187 | static int read_intra_function_calls(struct objtool_file *file) |
2188 | { | |
2189 | struct instruction *insn; | |
2190 | struct section *sec; | |
f1974222 | 2191 | struct reloc *reloc; |
8aa8eb2a AC |
2192 | |
2193 | sec = find_section_by_name(file->elf, ".rela.discard.intra_function_calls"); | |
2194 | if (!sec) | |
2195 | return 0; | |
2196 | ||
f1974222 | 2197 | list_for_each_entry(reloc, &sec->reloc_list, list) { |
8aa8eb2a AC |
2198 | unsigned long dest_off; |
2199 | ||
f1974222 | 2200 | if (reloc->sym->type != STT_SECTION) { |
8aa8eb2a AC |
2201 | WARN("unexpected relocation symbol type in %s", |
2202 | sec->name); | |
2203 | return -1; | |
2204 | } | |
2205 | ||
f1974222 | 2206 | insn = find_insn(file, reloc->sym->sec, reloc->addend); |
8aa8eb2a AC |
2207 | if (!insn) { |
2208 | WARN("bad .discard.intra_function_call entry"); | |
2209 | return -1; | |
2210 | } | |
2211 | ||
2212 | if (insn->type != INSN_CALL) { | |
2213 | WARN_FUNC("intra_function_call not a direct call", | |
2214 | insn->sec, insn->offset); | |
2215 | return -1; | |
2216 | } | |
2217 | ||
2218 | /* | |
2219 | * Treat intra-function CALLs as JMPs, but with a stack_op. | |
2220 | * See add_call_destinations(), which strips stack_ops from | |
2221 | * normal CALLs. | |
2222 | */ | |
2223 | insn->type = INSN_JUMP_UNCONDITIONAL; | |
2224 | ||
2225 | dest_off = insn->offset + insn->len + insn->immediate; | |
2226 | insn->jump_dest = find_insn(file, insn->sec, dest_off); | |
2227 | if (!insn->jump_dest) { | |
2228 | WARN_FUNC("can't find call dest at %s+0x%lx", | |
2229 | insn->sec, insn->offset, | |
2230 | insn->sec->name, dest_off); | |
2231 | return -1; | |
2232 | } | |
2233 | } | |
2234 | ||
2235 | return 0; | |
2236 | } | |
2237 | ||
05098119 ME |
2238 | /* |
2239 | * Return true if name matches an instrumentation function, where calls to that | |
2240 | * function from noinstr code can safely be removed, but compilers won't do so. | |
2241 | */ | |
2242 | static bool is_profiling_func(const char *name) | |
2243 | { | |
2244 | /* | |
2245 | * Many compilers cannot disable KCOV with a function attribute. | |
2246 | */ | |
2247 | if (!strncmp(name, "__sanitizer_cov_", 16)) | |
2248 | return true; | |
2249 | ||
2250 | /* | |
2251 | * Some compilers currently do not remove __tsan_func_entry/exit nor | |
2252 | * __tsan_atomic_signal_fence (used for barrier instrumentation) with | |
2253 | * the __no_sanitize_thread attribute, remove them. Once the kernel's | |
2254 | * minimum Clang version is 14.0, this can be removed. | |
2255 | */ | |
2256 | if (!strncmp(name, "__tsan_func_", 12) || | |
2257 | !strcmp(name, "__tsan_atomic_signal_fence")) | |
2258 | return true; | |
2259 | ||
2260 | return false; | |
2261 | } | |
2262 | ||
1739c66e | 2263 | static int classify_symbols(struct objtool_file *file) |
1e7e4788 JP |
2264 | { |
2265 | struct section *sec; | |
2266 | struct symbol *func; | |
2267 | ||
2268 | for_each_sec(file, sec) { | |
2269 | list_for_each_entry(func, &sec->symbol_list, list) { | |
1739c66e PZ |
2270 | if (func->bind != STB_GLOBAL) |
2271 | continue; | |
2272 | ||
2273 | if (!strncmp(func->name, STATIC_CALL_TRAMP_PREFIX_STR, | |
1e7e4788 JP |
2274 | strlen(STATIC_CALL_TRAMP_PREFIX_STR))) |
2275 | func->static_call_tramp = true; | |
1739c66e PZ |
2276 | |
2277 | if (arch_is_retpoline(func)) | |
2278 | func->retpoline_thunk = true; | |
2279 | ||
d9e9d230 PZ |
2280 | if (arch_is_rethunk(func)) |
2281 | func->return_thunk = true; | |
2282 | ||
1739c66e PZ |
2283 | if (!strcmp(func->name, "__fentry__")) |
2284 | func->fentry = true; | |
2285 | ||
05098119 ME |
2286 | if (is_profiling_func(func->name)) |
2287 | func->profiling_func = true; | |
1e7e4788 JP |
2288 | } |
2289 | } | |
2290 | ||
2291 | return 0; | |
2292 | } | |
2293 | ||
4a60aa05 AX |
2294 | static void mark_rodata(struct objtool_file *file) |
2295 | { | |
2296 | struct section *sec; | |
2297 | bool found = false; | |
2298 | ||
2299 | /* | |
87b512de JP |
2300 | * Search for the following rodata sections, each of which can |
2301 | * potentially contain jump tables: | |
2302 | * | |
2303 | * - .rodata: can contain GCC switch tables | |
2304 | * - .rodata.<func>: same, if -fdata-sections is being used | |
2305 | * - .rodata..c_jump_table: contains C annotated jump tables | |
2306 | * | |
2307 | * .rodata.str1.* sections are ignored; they don't contain jump tables. | |
4a60aa05 AX |
2308 | */ |
2309 | for_each_sec(file, sec) { | |
1ee44470 MS |
2310 | if (!strncmp(sec->name, ".rodata", 7) && |
2311 | !strstr(sec->name, ".str1.")) { | |
4a60aa05 AX |
2312 | sec->rodata = true; |
2313 | found = true; | |
2314 | } | |
2315 | } | |
2316 | ||
2317 | file->rodata = found; | |
2318 | } | |
2319 | ||
dcc914f4 JP |
2320 | static int decode_sections(struct objtool_file *file) |
2321 | { | |
2322 | int ret; | |
2323 | ||
4a60aa05 AX |
2324 | mark_rodata(file); |
2325 | ||
db2b0c5d PZ |
2326 | ret = init_pv_ops(file); |
2327 | if (ret) | |
2328 | return ret; | |
2329 | ||
dcc914f4 JP |
2330 | ret = decode_instructions(file); |
2331 | if (ret) | |
2332 | return ret; | |
2333 | ||
dcc914f4 | 2334 | add_ignores(file); |
ea24213d | 2335 | add_uaccess_safe(file); |
dcc914f4 | 2336 | |
ff05ab23 | 2337 | ret = add_ignore_alternatives(file); |
258c7605 JP |
2338 | if (ret) |
2339 | return ret; | |
2340 | ||
08f87a93 PZ |
2341 | /* |
2342 | * Must be before read_unwind_hints() since that needs insn->noendbr. | |
2343 | */ | |
96db4a98 PZ |
2344 | ret = read_noendbr_hints(file); |
2345 | if (ret) | |
2346 | return ret; | |
2347 | ||
a958c4fe PZ |
2348 | /* |
2349 | * Must be before add_{jump_call}_destination. | |
2350 | */ | |
1739c66e | 2351 | ret = classify_symbols(file); |
5b06fd3b PZ |
2352 | if (ret) |
2353 | return ret; | |
2354 | ||
43d5430a | 2355 | /* |
34c861e8 JP |
2356 | * Must be before add_jump_destinations(), which depends on 'func' |
2357 | * being set for alternatives, to enable proper sibling call detection. | |
43d5430a | 2358 | */ |
34c861e8 | 2359 | ret = add_special_section_alts(file); |
dcc914f4 JP |
2360 | if (ret) |
2361 | return ret; | |
2362 | ||
34c861e8 | 2363 | ret = add_jump_destinations(file); |
dcc914f4 JP |
2364 | if (ret) |
2365 | return ret; | |
2366 | ||
a958c4fe PZ |
2367 | /* |
2368 | * Must be before add_call_destination(); it changes INSN_CALL to | |
2369 | * INSN_JUMP. | |
2370 | */ | |
8aa8eb2a AC |
2371 | ret = read_intra_function_calls(file); |
2372 | if (ret) | |
2373 | return ret; | |
2374 | ||
a845c7cf | 2375 | ret = add_call_destinations(file); |
dcc914f4 JP |
2376 | if (ret) |
2377 | return ret; | |
2378 | ||
0e5b613b PZ |
2379 | /* |
2380 | * Must be after add_call_destinations() such that it can override | |
2381 | * dead_end_function() marks. | |
2382 | */ | |
2383 | ret = add_dead_ends(file); | |
2384 | if (ret) | |
2385 | return ret; | |
2386 | ||
e7c2bc37 | 2387 | ret = add_jump_table_alts(file); |
dcc914f4 JP |
2388 | if (ret) |
2389 | return ret; | |
2390 | ||
39358a03 JP |
2391 | ret = read_unwind_hints(file); |
2392 | if (ret) | |
2393 | return ret; | |
2394 | ||
b5bc2231 PZ |
2395 | ret = read_retpoline_hints(file); |
2396 | if (ret) | |
2397 | return ret; | |
2398 | ||
c4a33939 PZ |
2399 | ret = read_instr_hints(file); |
2400 | if (ret) | |
2401 | return ret; | |
2402 | ||
dcc914f4 JP |
2403 | return 0; |
2404 | } | |
2405 | ||
2406 | static bool is_fentry_call(struct instruction *insn) | |
2407 | { | |
1739c66e PZ |
2408 | if (insn->type == INSN_CALL && |
2409 | insn->call_dest && | |
2410 | insn->call_dest->fentry) | |
dcc914f4 JP |
2411 | return true; |
2412 | ||
2413 | return false; | |
2414 | } | |
2415 | ||
e25eea89 | 2416 | static bool has_modified_stack_frame(struct instruction *insn, struct insn_state *state) |
dcc914f4 | 2417 | { |
e7c0219b | 2418 | struct cfi_state *cfi = &state->cfi; |
baa41469 JP |
2419 | int i; |
2420 | ||
e7c0219b | 2421 | if (cfi->cfa.base != initial_func_cfi.cfa.base || cfi->drap) |
e25eea89 PZ |
2422 | return true; |
2423 | ||
b735bd3e | 2424 | if (cfi->cfa.offset != initial_func_cfi.cfa.offset) |
baa41469 JP |
2425 | return true; |
2426 | ||
b735bd3e | 2427 | if (cfi->stack_size != initial_func_cfi.cfa.offset) |
e25eea89 PZ |
2428 | return true; |
2429 | ||
2430 | for (i = 0; i < CFI_NUM_REGS; i++) { | |
e7c0219b PZ |
2431 | if (cfi->regs[i].base != initial_func_cfi.regs[i].base || |
2432 | cfi->regs[i].offset != initial_func_cfi.regs[i].offset) | |
baa41469 | 2433 | return true; |
e25eea89 | 2434 | } |
baa41469 JP |
2435 | |
2436 | return false; | |
2437 | } | |
2438 | ||
fb084fde JT |
2439 | static bool check_reg_frame_pos(const struct cfi_reg *reg, |
2440 | int expected_offset) | |
2441 | { | |
2442 | return reg->base == CFI_CFA && | |
2443 | reg->offset == expected_offset; | |
2444 | } | |
2445 | ||
baa41469 JP |
2446 | static bool has_valid_stack_frame(struct insn_state *state) |
2447 | { | |
e7c0219b PZ |
2448 | struct cfi_state *cfi = &state->cfi; |
2449 | ||
fb084fde JT |
2450 | if (cfi->cfa.base == CFI_BP && |
2451 | check_reg_frame_pos(&cfi->regs[CFI_BP], -cfi->cfa.offset) && | |
2452 | check_reg_frame_pos(&cfi->regs[CFI_RA], -cfi->cfa.offset + 8)) | |
baa41469 JP |
2453 | return true; |
2454 | ||
e7c0219b | 2455 | if (cfi->drap && cfi->regs[CFI_BP].base == CFI_BP) |
baa41469 JP |
2456 | return true; |
2457 | ||
2458 | return false; | |
dcc914f4 JP |
2459 | } |
2460 | ||
e7c0219b PZ |
2461 | static int update_cfi_state_regs(struct instruction *insn, |
2462 | struct cfi_state *cfi, | |
65ea47dc | 2463 | struct stack_op *op) |
627fce14 | 2464 | { |
e7c0219b | 2465 | struct cfi_reg *cfa = &cfi->cfa; |
627fce14 | 2466 | |
d8dd25a4 | 2467 | if (cfa->base != CFI_SP && cfa->base != CFI_SP_INDIRECT) |
627fce14 JP |
2468 | return 0; |
2469 | ||
2470 | /* push */ | |
ea24213d | 2471 | if (op->dest.type == OP_DEST_PUSH || op->dest.type == OP_DEST_PUSHF) |
627fce14 JP |
2472 | cfa->offset += 8; |
2473 | ||
2474 | /* pop */ | |
ea24213d | 2475 | if (op->src.type == OP_SRC_POP || op->src.type == OP_SRC_POPF) |
627fce14 JP |
2476 | cfa->offset -= 8; |
2477 | ||
2478 | /* add immediate to sp */ | |
2479 | if (op->dest.type == OP_DEST_REG && op->src.type == OP_SRC_ADD && | |
2480 | op->dest.reg == CFI_SP && op->src.reg == CFI_SP) | |
2481 | cfa->offset -= op->src.offset; | |
2482 | ||
2483 | return 0; | |
2484 | } | |
2485 | ||
e7c0219b | 2486 | static void save_reg(struct cfi_state *cfi, unsigned char reg, int base, int offset) |
dcc914f4 | 2487 | { |
bf4d1a83 | 2488 | if (arch_callee_saved_reg(reg) && |
e7c0219b PZ |
2489 | cfi->regs[reg].base == CFI_UNDEFINED) { |
2490 | cfi->regs[reg].base = base; | |
2491 | cfi->regs[reg].offset = offset; | |
baa41469 | 2492 | } |
dcc914f4 JP |
2493 | } |
2494 | ||
e7c0219b | 2495 | static void restore_reg(struct cfi_state *cfi, unsigned char reg) |
dcc914f4 | 2496 | { |
e7c0219b PZ |
2497 | cfi->regs[reg].base = initial_func_cfi.regs[reg].base; |
2498 | cfi->regs[reg].offset = initial_func_cfi.regs[reg].offset; | |
baa41469 JP |
2499 | } |
2500 | ||
2501 | /* | |
2502 | * A note about DRAP stack alignment: | |
2503 | * | |
2504 | * GCC has the concept of a DRAP register, which is used to help keep track of | |
2505 | * the stack pointer when aligning the stack. r10 or r13 is used as the DRAP | |
2506 | * register. The typical DRAP pattern is: | |
2507 | * | |
2508 | * 4c 8d 54 24 08 lea 0x8(%rsp),%r10 | |
2509 | * 48 83 e4 c0 and $0xffffffffffffffc0,%rsp | |
2510 | * 41 ff 72 f8 pushq -0x8(%r10) | |
2511 | * 55 push %rbp | |
2512 | * 48 89 e5 mov %rsp,%rbp | |
2513 | * (more pushes) | |
2514 | * 41 52 push %r10 | |
2515 | * ... | |
2516 | * 41 5a pop %r10 | |
2517 | * (more pops) | |
2518 | * 5d pop %rbp | |
2519 | * 49 8d 62 f8 lea -0x8(%r10),%rsp | |
2520 | * c3 retq | |
2521 | * | |
2522 | * There are some variations in the epilogues, like: | |
2523 | * | |
2524 | * 5b pop %rbx | |
2525 | * 41 5a pop %r10 | |
2526 | * 41 5c pop %r12 | |
2527 | * 41 5d pop %r13 | |
2528 | * 41 5e pop %r14 | |
2529 | * c9 leaveq | |
2530 | * 49 8d 62 f8 lea -0x8(%r10),%rsp | |
2531 | * c3 retq | |
2532 | * | |
2533 | * and: | |
2534 | * | |
2535 | * 4c 8b 55 e8 mov -0x18(%rbp),%r10 | |
2536 | * 48 8b 5d e0 mov -0x20(%rbp),%rbx | |
2537 | * 4c 8b 65 f0 mov -0x10(%rbp),%r12 | |
2538 | * 4c 8b 6d f8 mov -0x8(%rbp),%r13 | |
2539 | * c9 leaveq | |
2540 | * 49 8d 62 f8 lea -0x8(%r10),%rsp | |
2541 | * c3 retq | |
2542 | * | |
2543 | * Sometimes r13 is used as the DRAP register, in which case it's saved and | |
2544 | * restored beforehand: | |
2545 | * | |
2546 | * 41 55 push %r13 | |
2547 | * 4c 8d 6c 24 10 lea 0x10(%rsp),%r13 | |
2548 | * 48 83 e4 f0 and $0xfffffffffffffff0,%rsp | |
2549 | * ... | |
2550 | * 49 8d 65 f0 lea -0x10(%r13),%rsp | |
2551 | * 41 5d pop %r13 | |
2552 | * c3 retq | |
2553 | */ | |
d54dba41 PZ |
2554 | static int update_cfi_state(struct instruction *insn, |
2555 | struct instruction *next_insn, | |
2556 | struct cfi_state *cfi, struct stack_op *op) | |
baa41469 | 2557 | { |
e7c0219b PZ |
2558 | struct cfi_reg *cfa = &cfi->cfa; |
2559 | struct cfi_reg *regs = cfi->regs; | |
baa41469 JP |
2560 | |
2561 | /* stack operations don't make sense with an undefined CFA */ | |
2562 | if (cfa->base == CFI_UNDEFINED) { | |
2563 | if (insn->func) { | |
2564 | WARN_FUNC("undefined stack state", insn->sec, insn->offset); | |
2565 | return -1; | |
2566 | } | |
2567 | return 0; | |
2568 | } | |
2569 | ||
ee819aed JT |
2570 | if (cfi->type == UNWIND_HINT_TYPE_REGS || |
2571 | cfi->type == UNWIND_HINT_TYPE_REGS_PARTIAL) | |
e7c0219b | 2572 | return update_cfi_state_regs(insn, cfi, op); |
627fce14 | 2573 | |
baa41469 JP |
2574 | switch (op->dest.type) { |
2575 | ||
2576 | case OP_DEST_REG: | |
2577 | switch (op->src.type) { | |
2578 | ||
2579 | case OP_SRC_REG: | |
0d0970ee JP |
2580 | if (op->src.reg == CFI_SP && op->dest.reg == CFI_BP && |
2581 | cfa->base == CFI_SP && | |
fb084fde | 2582 | check_reg_frame_pos(®s[CFI_BP], -cfa->offset)) { |
0d0970ee JP |
2583 | |
2584 | /* mov %rsp, %rbp */ | |
2585 | cfa->base = op->dest.reg; | |
e7c0219b | 2586 | cfi->bp_scratch = false; |
0d0970ee | 2587 | } |
dd88a0a0 | 2588 | |
0d0970ee | 2589 | else if (op->src.reg == CFI_SP && |
e7c0219b | 2590 | op->dest.reg == CFI_BP && cfi->drap) { |
dd88a0a0 | 2591 | |
0d0970ee JP |
2592 | /* drap: mov %rsp, %rbp */ |
2593 | regs[CFI_BP].base = CFI_BP; | |
e7c0219b PZ |
2594 | regs[CFI_BP].offset = -cfi->stack_size; |
2595 | cfi->bp_scratch = false; | |
0d0970ee | 2596 | } |
dd88a0a0 | 2597 | |
0d0970ee JP |
2598 | else if (op->src.reg == CFI_SP && cfa->base == CFI_SP) { |
2599 | ||
2600 | /* | |
2601 | * mov %rsp, %reg | |
2602 | * | |
2603 | * This is needed for the rare case where GCC | |
2604 | * does: | |
2605 | * | |
2606 | * mov %rsp, %rax | |
2607 | * ... | |
2608 | * mov %rax, %rsp | |
2609 | */ | |
e7c0219b PZ |
2610 | cfi->vals[op->dest.reg].base = CFI_CFA; |
2611 | cfi->vals[op->dest.reg].offset = -cfi->stack_size; | |
dd88a0a0 JP |
2612 | } |
2613 | ||
3c1f0583 | 2614 | else if (op->src.reg == CFI_BP && op->dest.reg == CFI_SP && |
ffc7e74f | 2615 | (cfa->base == CFI_BP || cfa->base == cfi->drap_reg)) { |
3c1f0583 JP |
2616 | |
2617 | /* | |
2618 | * mov %rbp, %rsp | |
2619 | * | |
2620 | * Restore the original stack pointer (Clang). | |
2621 | */ | |
e7c0219b | 2622 | cfi->stack_size = -cfi->regs[CFI_BP].offset; |
3c1f0583 JP |
2623 | } |
2624 | ||
dd88a0a0 JP |
2625 | else if (op->dest.reg == cfa->base) { |
2626 | ||
2627 | /* mov %reg, %rsp */ | |
2628 | if (cfa->base == CFI_SP && | |
e7c0219b | 2629 | cfi->vals[op->src.reg].base == CFI_CFA) { |
dd88a0a0 JP |
2630 | |
2631 | /* | |
2632 | * This is needed for the rare case | |
2633 | * where GCC does something dumb like: | |
2634 | * | |
2635 | * lea 0x8(%rsp), %rcx | |
2636 | * ... | |
2637 | * mov %rcx, %rsp | |
2638 | */ | |
e7c0219b PZ |
2639 | cfa->offset = -cfi->vals[op->src.reg].offset; |
2640 | cfi->stack_size = cfa->offset; | |
dd88a0a0 | 2641 | |
aafeb14e PZ |
2642 | } else if (cfa->base == CFI_SP && |
2643 | cfi->vals[op->src.reg].base == CFI_SP_INDIRECT && | |
2644 | cfi->vals[op->src.reg].offset == cfa->offset) { | |
2645 | ||
2646 | /* | |
2647 | * Stack swizzle: | |
2648 | * | |
2649 | * 1: mov %rsp, (%[tos]) | |
2650 | * 2: mov %[tos], %rsp | |
2651 | * ... | |
2652 | * 3: pop %rsp | |
2653 | * | |
2654 | * Where: | |
2655 | * | |
2656 | * 1 - places a pointer to the previous | |
2657 | * stack at the Top-of-Stack of the | |
2658 | * new stack. | |
2659 | * | |
2660 | * 2 - switches to the new stack. | |
2661 | * | |
2662 | * 3 - pops the Top-of-Stack to restore | |
2663 | * the original stack. | |
2664 | * | |
2665 | * Note: we set base to SP_INDIRECT | |
2666 | * here and preserve offset. Therefore | |
2667 | * when the unwinder reaches ToS it | |
2668 | * will dereference SP and then add the | |
2669 | * offset to find the next frame, IOW: | |
2670 | * (%rsp) + offset. | |
2671 | */ | |
2672 | cfa->base = CFI_SP_INDIRECT; | |
2673 | ||
dd88a0a0 JP |
2674 | } else { |
2675 | cfa->base = CFI_UNDEFINED; | |
2676 | cfa->offset = 0; | |
2677 | } | |
baa41469 JP |
2678 | } |
2679 | ||
724c8a23 PZ |
2680 | else if (op->dest.reg == CFI_SP && |
2681 | cfi->vals[op->src.reg].base == CFI_SP_INDIRECT && | |
2682 | cfi->vals[op->src.reg].offset == cfa->offset) { | |
2683 | ||
2684 | /* | |
2685 | * The same stack swizzle case 2) as above. But | |
2686 | * because we can't change cfa->base, case 3) | |
2687 | * will become a regular POP. Pretend we're a | |
2688 | * PUSH so things don't go unbalanced. | |
2689 | */ | |
2690 | cfi->stack_size += 8; | |
2691 | } | |
2692 | ||
2693 | ||
baa41469 JP |
2694 | break; |
2695 | ||
2696 | case OP_SRC_ADD: | |
2697 | if (op->dest.reg == CFI_SP && op->src.reg == CFI_SP) { | |
2698 | ||
2699 | /* add imm, %rsp */ | |
e7c0219b | 2700 | cfi->stack_size -= op->src.offset; |
baa41469 JP |
2701 | if (cfa->base == CFI_SP) |
2702 | cfa->offset -= op->src.offset; | |
2703 | break; | |
2704 | } | |
2705 | ||
2706 | if (op->dest.reg == CFI_SP && op->src.reg == CFI_BP) { | |
2707 | ||
2708 | /* lea disp(%rbp), %rsp */ | |
e7c0219b | 2709 | cfi->stack_size = -(op->src.offset + regs[CFI_BP].offset); |
baa41469 JP |
2710 | break; |
2711 | } | |
2712 | ||
468af56a JT |
2713 | if (!cfi->drap && op->src.reg == CFI_SP && |
2714 | op->dest.reg == CFI_BP && cfa->base == CFI_SP && | |
2715 | check_reg_frame_pos(®s[CFI_BP], -cfa->offset + op->src.offset)) { | |
2716 | ||
2717 | /* lea disp(%rsp), %rbp */ | |
2718 | cfa->base = CFI_BP; | |
2719 | cfa->offset -= op->src.offset; | |
2720 | cfi->bp_scratch = false; | |
2721 | break; | |
2722 | } | |
2723 | ||
dd88a0a0 | 2724 | if (op->src.reg == CFI_SP && cfa->base == CFI_SP) { |
baa41469 JP |
2725 | |
2726 | /* drap: lea disp(%rsp), %drap */ | |
e7c0219b | 2727 | cfi->drap_reg = op->dest.reg; |
dd88a0a0 JP |
2728 | |
2729 | /* | |
2730 | * lea disp(%rsp), %reg | |
2731 | * | |
2732 | * This is needed for the rare case where GCC | |
2733 | * does something dumb like: | |
2734 | * | |
2735 | * lea 0x8(%rsp), %rcx | |
2736 | * ... | |
2737 | * mov %rcx, %rsp | |
2738 | */ | |
e7c0219b PZ |
2739 | cfi->vals[op->dest.reg].base = CFI_CFA; |
2740 | cfi->vals[op->dest.reg].offset = \ | |
2741 | -cfi->stack_size + op->src.offset; | |
dd88a0a0 | 2742 | |
baa41469 JP |
2743 | break; |
2744 | } | |
2745 | ||
e7c0219b PZ |
2746 | if (cfi->drap && op->dest.reg == CFI_SP && |
2747 | op->src.reg == cfi->drap_reg) { | |
baa41469 JP |
2748 | |
2749 | /* drap: lea disp(%drap), %rsp */ | |
2750 | cfa->base = CFI_SP; | |
e7c0219b PZ |
2751 | cfa->offset = cfi->stack_size = -op->src.offset; |
2752 | cfi->drap_reg = CFI_UNDEFINED; | |
2753 | cfi->drap = false; | |
baa41469 JP |
2754 | break; |
2755 | } | |
2756 | ||
d54dba41 | 2757 | if (op->dest.reg == cfi->cfa.base && !(next_insn && next_insn->hint)) { |
baa41469 JP |
2758 | WARN_FUNC("unsupported stack register modification", |
2759 | insn->sec, insn->offset); | |
2760 | return -1; | |
2761 | } | |
2762 | ||
2763 | break; | |
2764 | ||
2765 | case OP_SRC_AND: | |
2766 | if (op->dest.reg != CFI_SP || | |
e7c0219b PZ |
2767 | (cfi->drap_reg != CFI_UNDEFINED && cfa->base != CFI_SP) || |
2768 | (cfi->drap_reg == CFI_UNDEFINED && cfa->base != CFI_BP)) { | |
baa41469 JP |
2769 | WARN_FUNC("unsupported stack pointer realignment", |
2770 | insn->sec, insn->offset); | |
2771 | return -1; | |
2772 | } | |
2773 | ||
e7c0219b | 2774 | if (cfi->drap_reg != CFI_UNDEFINED) { |
baa41469 | 2775 | /* drap: and imm, %rsp */ |
e7c0219b PZ |
2776 | cfa->base = cfi->drap_reg; |
2777 | cfa->offset = cfi->stack_size = 0; | |
2778 | cfi->drap = true; | |
baa41469 JP |
2779 | } |
2780 | ||
2781 | /* | |
2782 | * Older versions of GCC (4.8ish) realign the stack | |
2783 | * without DRAP, with a frame pointer. | |
2784 | */ | |
2785 | ||
2786 | break; | |
2787 | ||
2788 | case OP_SRC_POP: | |
ea24213d | 2789 | case OP_SRC_POPF: |
aafeb14e PZ |
2790 | if (op->dest.reg == CFI_SP && cfa->base == CFI_SP_INDIRECT) { |
2791 | ||
2792 | /* pop %rsp; # restore from a stack swizzle */ | |
2793 | cfa->base = CFI_SP; | |
2794 | break; | |
2795 | } | |
2796 | ||
e7c0219b | 2797 | if (!cfi->drap && op->dest.reg == cfa->base) { |
baa41469 JP |
2798 | |
2799 | /* pop %rbp */ | |
2800 | cfa->base = CFI_SP; | |
2801 | } | |
2802 | ||
e7c0219b PZ |
2803 | if (cfi->drap && cfa->base == CFI_BP_INDIRECT && |
2804 | op->dest.reg == cfi->drap_reg && | |
2805 | cfi->drap_offset == -cfi->stack_size) { | |
baa41469 | 2806 | |
bf4d1a83 | 2807 | /* drap: pop %drap */ |
e7c0219b | 2808 | cfa->base = cfi->drap_reg; |
bf4d1a83 | 2809 | cfa->offset = 0; |
e7c0219b | 2810 | cfi->drap_offset = -1; |
baa41469 | 2811 | |
ffc7e74f | 2812 | } else if (cfi->stack_size == -regs[op->dest.reg].offset) { |
baa41469 | 2813 | |
bf4d1a83 | 2814 | /* pop %reg */ |
e7c0219b | 2815 | restore_reg(cfi, op->dest.reg); |
baa41469 JP |
2816 | } |
2817 | ||
e7c0219b | 2818 | cfi->stack_size -= 8; |
baa41469 JP |
2819 | if (cfa->base == CFI_SP) |
2820 | cfa->offset -= 8; | |
2821 | ||
2822 | break; | |
2823 | ||
2824 | case OP_SRC_REG_INDIRECT: | |
201ef5a9 JT |
2825 | if (!cfi->drap && op->dest.reg == cfa->base && |
2826 | op->dest.reg == CFI_BP) { | |
2827 | ||
2828 | /* mov disp(%rsp), %rbp */ | |
2829 | cfa->base = CFI_SP; | |
2830 | cfa->offset = cfi->stack_size; | |
2831 | } | |
2832 | ||
e7c0219b PZ |
2833 | if (cfi->drap && op->src.reg == CFI_BP && |
2834 | op->src.offset == cfi->drap_offset) { | |
bf4d1a83 JP |
2835 | |
2836 | /* drap: mov disp(%rbp), %drap */ | |
e7c0219b | 2837 | cfa->base = cfi->drap_reg; |
bf4d1a83 | 2838 | cfa->offset = 0; |
e7c0219b | 2839 | cfi->drap_offset = -1; |
bf4d1a83 JP |
2840 | } |
2841 | ||
e7c0219b | 2842 | if (cfi->drap && op->src.reg == CFI_BP && |
baa41469 JP |
2843 | op->src.offset == regs[op->dest.reg].offset) { |
2844 | ||
2845 | /* drap: mov disp(%rbp), %reg */ | |
e7c0219b | 2846 | restore_reg(cfi, op->dest.reg); |
baa41469 JP |
2847 | |
2848 | } else if (op->src.reg == cfa->base && | |
2849 | op->src.offset == regs[op->dest.reg].offset + cfa->offset) { | |
2850 | ||
2851 | /* mov disp(%rbp), %reg */ | |
2852 | /* mov disp(%rsp), %reg */ | |
e7c0219b | 2853 | restore_reg(cfi, op->dest.reg); |
201ef5a9 JT |
2854 | |
2855 | } else if (op->src.reg == CFI_SP && | |
2856 | op->src.offset == regs[op->dest.reg].offset + cfi->stack_size) { | |
2857 | ||
2858 | /* mov disp(%rsp), %reg */ | |
2859 | restore_reg(cfi, op->dest.reg); | |
baa41469 JP |
2860 | } |
2861 | ||
2862 | break; | |
2863 | ||
2864 | default: | |
2865 | WARN_FUNC("unknown stack-related instruction", | |
2866 | insn->sec, insn->offset); | |
2867 | return -1; | |
2868 | } | |
2869 | ||
2870 | break; | |
2871 | ||
2872 | case OP_DEST_PUSH: | |
ea24213d | 2873 | case OP_DEST_PUSHF: |
e7c0219b | 2874 | cfi->stack_size += 8; |
baa41469 JP |
2875 | if (cfa->base == CFI_SP) |
2876 | cfa->offset += 8; | |
2877 | ||
2878 | if (op->src.type != OP_SRC_REG) | |
2879 | break; | |
2880 | ||
e7c0219b PZ |
2881 | if (cfi->drap) { |
2882 | if (op->src.reg == cfa->base && op->src.reg == cfi->drap_reg) { | |
baa41469 JP |
2883 | |
2884 | /* drap: push %drap */ | |
2885 | cfa->base = CFI_BP_INDIRECT; | |
e7c0219b | 2886 | cfa->offset = -cfi->stack_size; |
baa41469 | 2887 | |
bf4d1a83 | 2888 | /* save drap so we know when to restore it */ |
e7c0219b | 2889 | cfi->drap_offset = -cfi->stack_size; |
baa41469 | 2890 | |
e7c0219b | 2891 | } else if (op->src.reg == CFI_BP && cfa->base == cfi->drap_reg) { |
baa41469 JP |
2892 | |
2893 | /* drap: push %rbp */ | |
e7c0219b | 2894 | cfi->stack_size = 0; |
baa41469 | 2895 | |
f4f80398 | 2896 | } else { |
baa41469 JP |
2897 | |
2898 | /* drap: push %reg */ | |
e7c0219b | 2899 | save_reg(cfi, op->src.reg, CFI_BP, -cfi->stack_size); |
baa41469 JP |
2900 | } |
2901 | ||
2902 | } else { | |
2903 | ||
2904 | /* push %reg */ | |
e7c0219b | 2905 | save_reg(cfi, op->src.reg, CFI_CFA, -cfi->stack_size); |
baa41469 JP |
2906 | } |
2907 | ||
2908 | /* detect when asm code uses rbp as a scratch register */ | |
72064474 | 2909 | if (opts.stackval && insn->func && op->src.reg == CFI_BP && |
baa41469 | 2910 | cfa->base != CFI_BP) |
e7c0219b | 2911 | cfi->bp_scratch = true; |
baa41469 JP |
2912 | break; |
2913 | ||
2914 | case OP_DEST_REG_INDIRECT: | |
2915 | ||
e7c0219b PZ |
2916 | if (cfi->drap) { |
2917 | if (op->src.reg == cfa->base && op->src.reg == cfi->drap_reg) { | |
baa41469 JP |
2918 | |
2919 | /* drap: mov %drap, disp(%rbp) */ | |
2920 | cfa->base = CFI_BP_INDIRECT; | |
2921 | cfa->offset = op->dest.offset; | |
2922 | ||
bf4d1a83 | 2923 | /* save drap offset so we know when to restore it */ |
e7c0219b | 2924 | cfi->drap_offset = op->dest.offset; |
f4f80398 | 2925 | } else { |
baa41469 JP |
2926 | |
2927 | /* drap: mov reg, disp(%rbp) */ | |
e7c0219b | 2928 | save_reg(cfi, op->src.reg, CFI_BP, op->dest.offset); |
baa41469 JP |
2929 | } |
2930 | ||
2931 | } else if (op->dest.reg == cfa->base) { | |
2932 | ||
2933 | /* mov reg, disp(%rbp) */ | |
2934 | /* mov reg, disp(%rsp) */ | |
e7c0219b PZ |
2935 | save_reg(cfi, op->src.reg, CFI_CFA, |
2936 | op->dest.offset - cfi->cfa.offset); | |
201ef5a9 JT |
2937 | |
2938 | } else if (op->dest.reg == CFI_SP) { | |
2939 | ||
2940 | /* mov reg, disp(%rsp) */ | |
2941 | save_reg(cfi, op->src.reg, CFI_CFA, | |
2942 | op->dest.offset - cfi->stack_size); | |
aafeb14e PZ |
2943 | |
2944 | } else if (op->src.reg == CFI_SP && op->dest.offset == 0) { | |
2945 | ||
2946 | /* mov %rsp, (%reg); # setup a stack swizzle. */ | |
2947 | cfi->vals[op->dest.reg].base = CFI_SP_INDIRECT; | |
2948 | cfi->vals[op->dest.reg].offset = cfa->offset; | |
baa41469 JP |
2949 | } |
2950 | ||
2951 | break; | |
2952 | ||
baa41469 | 2953 | case OP_DEST_MEM: |
ea24213d | 2954 | if (op->src.type != OP_SRC_POP && op->src.type != OP_SRC_POPF) { |
baa41469 JP |
2955 | WARN_FUNC("unknown stack-related memory operation", |
2956 | insn->sec, insn->offset); | |
2957 | return -1; | |
2958 | } | |
2959 | ||
2960 | /* pop mem */ | |
e7c0219b | 2961 | cfi->stack_size -= 8; |
baa41469 JP |
2962 | if (cfa->base == CFI_SP) |
2963 | cfa->offset -= 8; | |
2964 | ||
2965 | break; | |
2966 | ||
2967 | default: | |
2968 | WARN_FUNC("unknown stack-related instruction", | |
2969 | insn->sec, insn->offset); | |
2970 | return -1; | |
2971 | } | |
2972 | ||
2973 | return 0; | |
2974 | } | |
2975 | ||
c9c324dc JP |
2976 | /* |
2977 | * The stack layouts of alternatives instructions can sometimes diverge when | |
2978 | * they have stack modifications. That's fine as long as the potential stack | |
2979 | * layouts don't conflict at any given potential instruction boundary. | |
2980 | * | |
2981 | * Flatten the CFIs of the different alternative code streams (both original | |
2982 | * and replacement) into a single shared CFI array which can be used to detect | |
2983 | * conflicts and nicely feed a linear array of ORC entries to the unwinder. | |
2984 | */ | |
2985 | static int propagate_alt_cfi(struct objtool_file *file, struct instruction *insn) | |
65ea47dc | 2986 | { |
c9c324dc JP |
2987 | struct cfi_state **alt_cfi; |
2988 | int group_off; | |
65ea47dc | 2989 | |
c9c324dc JP |
2990 | if (!insn->alt_group) |
2991 | return 0; | |
65ea47dc | 2992 | |
8b946cc3 PZ |
2993 | if (!insn->cfi) { |
2994 | WARN("CFI missing"); | |
2995 | return -1; | |
2996 | } | |
2997 | ||
c9c324dc JP |
2998 | alt_cfi = insn->alt_group->cfi; |
2999 | group_off = insn->offset - insn->alt_group->first_insn->offset; | |
65ea47dc | 3000 | |
c9c324dc | 3001 | if (!alt_cfi[group_off]) { |
8b946cc3 | 3002 | alt_cfi[group_off] = insn->cfi; |
c9c324dc | 3003 | } else { |
8b946cc3 | 3004 | if (cficmp(alt_cfi[group_off], insn->cfi)) { |
c9c324dc JP |
3005 | WARN_FUNC("stack layout conflict in alternatives", |
3006 | insn->sec, insn->offset); | |
ab3852ab PZ |
3007 | return -1; |
3008 | } | |
c9c324dc JP |
3009 | } |
3010 | ||
3011 | return 0; | |
3012 | } | |
3013 | ||
d54dba41 PZ |
3014 | static int handle_insn_ops(struct instruction *insn, |
3015 | struct instruction *next_insn, | |
3016 | struct insn_state *state) | |
c9c324dc JP |
3017 | { |
3018 | struct stack_op *op; | |
3019 | ||
3020 | list_for_each_entry(op, &insn->stack_ops, list) { | |
3021 | ||
d54dba41 | 3022 | if (update_cfi_state(insn, next_insn, &state->cfi, op)) |
c9c324dc | 3023 | return 1; |
ab3852ab | 3024 | |
ba08abca PZ |
3025 | if (!insn->alt_group) |
3026 | continue; | |
3027 | ||
65ea47dc JT |
3028 | if (op->dest.type == OP_DEST_PUSHF) { |
3029 | if (!state->uaccess_stack) { | |
3030 | state->uaccess_stack = 1; | |
3031 | } else if (state->uaccess_stack >> 31) { | |
3032 | WARN_FUNC("PUSHF stack exhausted", | |
3033 | insn->sec, insn->offset); | |
3034 | return 1; | |
3035 | } | |
3036 | state->uaccess_stack <<= 1; | |
3037 | state->uaccess_stack |= state->uaccess; | |
3038 | } | |
3039 | ||
3040 | if (op->src.type == OP_SRC_POPF) { | |
3041 | if (state->uaccess_stack) { | |
3042 | state->uaccess = state->uaccess_stack & 1; | |
3043 | state->uaccess_stack >>= 1; | |
3044 | if (state->uaccess_stack == 1) | |
3045 | state->uaccess_stack = 0; | |
3046 | } | |
3047 | } | |
3048 | } | |
3049 | ||
3050 | return 0; | |
3051 | } | |
3052 | ||
e7c0219b | 3053 | static bool insn_cfi_match(struct instruction *insn, struct cfi_state *cfi2) |
baa41469 | 3054 | { |
8b946cc3 | 3055 | struct cfi_state *cfi1 = insn->cfi; |
baa41469 JP |
3056 | int i; |
3057 | ||
8b946cc3 PZ |
3058 | if (!cfi1) { |
3059 | WARN("CFI missing"); | |
3060 | return false; | |
3061 | } | |
3062 | ||
e7c0219b PZ |
3063 | if (memcmp(&cfi1->cfa, &cfi2->cfa, sizeof(cfi1->cfa))) { |
3064 | ||
baa41469 JP |
3065 | WARN_FUNC("stack state mismatch: cfa1=%d%+d cfa2=%d%+d", |
3066 | insn->sec, insn->offset, | |
e7c0219b PZ |
3067 | cfi1->cfa.base, cfi1->cfa.offset, |
3068 | cfi2->cfa.base, cfi2->cfa.offset); | |
baa41469 | 3069 | |
e7c0219b | 3070 | } else if (memcmp(&cfi1->regs, &cfi2->regs, sizeof(cfi1->regs))) { |
baa41469 | 3071 | for (i = 0; i < CFI_NUM_REGS; i++) { |
e7c0219b | 3072 | if (!memcmp(&cfi1->regs[i], &cfi2->regs[i], |
baa41469 JP |
3073 | sizeof(struct cfi_reg))) |
3074 | continue; | |
3075 | ||
3076 | WARN_FUNC("stack state mismatch: reg1[%d]=%d%+d reg2[%d]=%d%+d", | |
3077 | insn->sec, insn->offset, | |
e7c0219b PZ |
3078 | i, cfi1->regs[i].base, cfi1->regs[i].offset, |
3079 | i, cfi2->regs[i].base, cfi2->regs[i].offset); | |
baa41469 JP |
3080 | break; |
3081 | } | |
3082 | ||
e7c0219b PZ |
3083 | } else if (cfi1->type != cfi2->type) { |
3084 | ||
627fce14 | 3085 | WARN_FUNC("stack state mismatch: type1=%d type2=%d", |
e7c0219b PZ |
3086 | insn->sec, insn->offset, cfi1->type, cfi2->type); |
3087 | ||
3088 | } else if (cfi1->drap != cfi2->drap || | |
3089 | (cfi1->drap && cfi1->drap_reg != cfi2->drap_reg) || | |
3090 | (cfi1->drap && cfi1->drap_offset != cfi2->drap_offset)) { | |
627fce14 | 3091 | |
bf4d1a83 | 3092 | WARN_FUNC("stack state mismatch: drap1=%d(%d,%d) drap2=%d(%d,%d)", |
baa41469 | 3093 | insn->sec, insn->offset, |
e7c0219b PZ |
3094 | cfi1->drap, cfi1->drap_reg, cfi1->drap_offset, |
3095 | cfi2->drap, cfi2->drap_reg, cfi2->drap_offset); | |
baa41469 JP |
3096 | |
3097 | } else | |
3098 | return true; | |
3099 | ||
3100 | return false; | |
dcc914f4 JP |
3101 | } |
3102 | ||
ea24213d PZ |
3103 | static inline bool func_uaccess_safe(struct symbol *func) |
3104 | { | |
3105 | if (func) | |
e10cd8fe | 3106 | return func->uaccess_safe; |
ea24213d PZ |
3107 | |
3108 | return false; | |
3109 | } | |
3110 | ||
0c1ddd33 | 3111 | static inline const char *call_dest_name(struct instruction *insn) |
ea24213d | 3112 | { |
82880283 | 3113 | static char pvname[19]; |
db2b0c5d PZ |
3114 | struct reloc *rel; |
3115 | int idx; | |
3116 | ||
ea24213d PZ |
3117 | if (insn->call_dest) |
3118 | return insn->call_dest->name; | |
3119 | ||
db2b0c5d PZ |
3120 | rel = insn_reloc(NULL, insn); |
3121 | if (rel && !strcmp(rel->sym->name, "pv_ops")) { | |
3122 | idx = (rel->addend / sizeof(void *)); | |
3123 | snprintf(pvname, sizeof(pvname), "pv_ops[%d]", idx); | |
3124 | return pvname; | |
3125 | } | |
3126 | ||
ea24213d PZ |
3127 | return "{dynamic}"; |
3128 | } | |
3129 | ||
db2b0c5d PZ |
3130 | static bool pv_call_dest(struct objtool_file *file, struct instruction *insn) |
3131 | { | |
3132 | struct symbol *target; | |
3133 | struct reloc *rel; | |
3134 | int idx; | |
3135 | ||
3136 | rel = insn_reloc(file, insn); | |
3137 | if (!rel || strcmp(rel->sym->name, "pv_ops")) | |
3138 | return false; | |
3139 | ||
3140 | idx = (arch_dest_reloc_offset(rel->addend) / sizeof(void *)); | |
3141 | ||
3142 | if (file->pv_ops[idx].clean) | |
3143 | return true; | |
3144 | ||
3145 | file->pv_ops[idx].clean = true; | |
3146 | ||
3147 | list_for_each_entry(target, &file->pv_ops[idx].targets, pv_target) { | |
3148 | if (!target->sec->noinstr) { | |
3149 | WARN("pv_ops[%d]: %s", idx, target->name); | |
3150 | file->pv_ops[idx].clean = false; | |
3151 | } | |
3152 | } | |
3153 | ||
3154 | return file->pv_ops[idx].clean; | |
3155 | } | |
3156 | ||
3157 | static inline bool noinstr_call_dest(struct objtool_file *file, | |
3158 | struct instruction *insn, | |
3159 | struct symbol *func) | |
6b643a07 PZ |
3160 | { |
3161 | /* | |
3162 | * We can't deal with indirect function calls at present; | |
3163 | * assume they're instrumented. | |
3164 | */ | |
db2b0c5d PZ |
3165 | if (!func) { |
3166 | if (file->pv_ops) | |
3167 | return pv_call_dest(file, insn); | |
3168 | ||
6b643a07 | 3169 | return false; |
db2b0c5d | 3170 | } |
6b643a07 PZ |
3171 | |
3172 | /* | |
3173 | * If the symbol is from a noinstr section; we good. | |
3174 | */ | |
3175 | if (func->sec->noinstr) | |
3176 | return true; | |
3177 | ||
3178 | /* | |
3179 | * The __ubsan_handle_*() calls are like WARN(), they only happen when | |
3180 | * something 'BAD' happened. At the risk of taking the machine down, | |
3181 | * let them proceed to get the message out. | |
3182 | */ | |
3183 | if (!strncmp(func->name, "__ubsan_handle_", 15)) | |
3184 | return true; | |
3185 | ||
3186 | return false; | |
3187 | } | |
3188 | ||
db2b0c5d PZ |
3189 | static int validate_call(struct objtool_file *file, |
3190 | struct instruction *insn, | |
3191 | struct insn_state *state) | |
ea24213d | 3192 | { |
c4a33939 | 3193 | if (state->noinstr && state->instr <= 0 && |
db2b0c5d | 3194 | !noinstr_call_dest(file, insn, insn->call_dest)) { |
c4a33939 PZ |
3195 | WARN_FUNC("call to %s() leaves .noinstr.text section", |
3196 | insn->sec, insn->offset, call_dest_name(insn)); | |
3197 | return 1; | |
3198 | } | |
3199 | ||
ea24213d PZ |
3200 | if (state->uaccess && !func_uaccess_safe(insn->call_dest)) { |
3201 | WARN_FUNC("call to %s() with UACCESS enabled", | |
0c1ddd33 | 3202 | insn->sec, insn->offset, call_dest_name(insn)); |
ea24213d PZ |
3203 | return 1; |
3204 | } | |
3205 | ||
2f0f9e9a PZ |
3206 | if (state->df) { |
3207 | WARN_FUNC("call to %s() with DF set", | |
0c1ddd33 | 3208 | insn->sec, insn->offset, call_dest_name(insn)); |
2f0f9e9a PZ |
3209 | return 1; |
3210 | } | |
3211 | ||
ea24213d PZ |
3212 | return 0; |
3213 | } | |
3214 | ||
db2b0c5d PZ |
3215 | static int validate_sibling_call(struct objtool_file *file, |
3216 | struct instruction *insn, | |
3217 | struct insn_state *state) | |
54262aa2 | 3218 | { |
e25eea89 | 3219 | if (has_modified_stack_frame(insn, state)) { |
54262aa2 PZ |
3220 | WARN_FUNC("sibling call from callable instruction with modified stack frame", |
3221 | insn->sec, insn->offset); | |
3222 | return 1; | |
3223 | } | |
3224 | ||
db2b0c5d | 3225 | return validate_call(file, insn, state); |
54262aa2 PZ |
3226 | } |
3227 | ||
a92e92d1 PZ |
3228 | static int validate_return(struct symbol *func, struct instruction *insn, struct insn_state *state) |
3229 | { | |
c4a33939 PZ |
3230 | if (state->noinstr && state->instr > 0) { |
3231 | WARN_FUNC("return with instrumentation enabled", | |
3232 | insn->sec, insn->offset); | |
3233 | return 1; | |
3234 | } | |
3235 | ||
a92e92d1 PZ |
3236 | if (state->uaccess && !func_uaccess_safe(func)) { |
3237 | WARN_FUNC("return with UACCESS enabled", | |
3238 | insn->sec, insn->offset); | |
3239 | return 1; | |
3240 | } | |
3241 | ||
3242 | if (!state->uaccess && func_uaccess_safe(func)) { | |
3243 | WARN_FUNC("return with UACCESS disabled from a UACCESS-safe function", | |
3244 | insn->sec, insn->offset); | |
3245 | return 1; | |
3246 | } | |
3247 | ||
3248 | if (state->df) { | |
3249 | WARN_FUNC("return with DF set", | |
3250 | insn->sec, insn->offset); | |
3251 | return 1; | |
3252 | } | |
3253 | ||
e25eea89 | 3254 | if (func && has_modified_stack_frame(insn, state)) { |
a92e92d1 PZ |
3255 | WARN_FUNC("return with modified stack frame", |
3256 | insn->sec, insn->offset); | |
3257 | return 1; | |
3258 | } | |
3259 | ||
e7c0219b | 3260 | if (state->cfi.bp_scratch) { |
b2966952 JP |
3261 | WARN_FUNC("BP used as a scratch register", |
3262 | insn->sec, insn->offset); | |
a92e92d1 PZ |
3263 | return 1; |
3264 | } | |
3265 | ||
3266 | return 0; | |
3267 | } | |
3268 | ||
c9c324dc JP |
3269 | static struct instruction *next_insn_to_validate(struct objtool_file *file, |
3270 | struct instruction *insn) | |
7117f16b | 3271 | { |
b23cc71c | 3272 | struct alt_group *alt_group = insn->alt_group; |
7117f16b | 3273 | |
c9c324dc JP |
3274 | /* |
3275 | * Simulate the fact that alternatives are patched in-place. When the | |
3276 | * end of a replacement alt_group is reached, redirect objtool flow to | |
3277 | * the end of the original alt_group. | |
3278 | */ | |
3279 | if (alt_group && insn == alt_group->last_insn && alt_group->orig_group) | |
3280 | return next_insn_same_sec(file, alt_group->orig_group->last_insn); | |
3281 | ||
3282 | return next_insn_same_sec(file, insn); | |
7117f16b PZ |
3283 | } |
3284 | ||
dcc914f4 JP |
3285 | /* |
3286 | * Follow the branch starting at the given instruction, and recursively follow | |
3287 | * any other branches (jumps). Meanwhile, track the frame pointer state at | |
3288 | * each instruction and validate all the rules described in | |
3289 | * tools/objtool/Documentation/stack-validation.txt. | |
3290 | */ | |
c705cecc | 3291 | static int validate_branch(struct objtool_file *file, struct symbol *func, |
b7460462 | 3292 | struct instruction *insn, struct insn_state state) |
dcc914f4 JP |
3293 | { |
3294 | struct alternative *alt; | |
8b946cc3 | 3295 | struct instruction *next_insn, *prev_insn = NULL; |
dcc914f4 | 3296 | struct section *sec; |
882a0db9 | 3297 | u8 visited; |
dcc914f4 JP |
3298 | int ret; |
3299 | ||
dcc914f4 | 3300 | sec = insn->sec; |
dcc914f4 | 3301 | |
dcc914f4 | 3302 | while (1) { |
c9c324dc | 3303 | next_insn = next_insn_to_validate(file, insn); |
39358a03 | 3304 | |
08feafe8 | 3305 | if (func && insn->func && func != insn->func->pfunc) { |
ee97638b JP |
3306 | WARN("%s() falls through to next function %s()", |
3307 | func->name, insn->func->name); | |
3308 | return 1; | |
dcc914f4 JP |
3309 | } |
3310 | ||
4855022a JP |
3311 | if (func && insn->ignore) { |
3312 | WARN_FUNC("BUG: why am I validating an ignored function?", | |
3313 | sec, insn->offset); | |
12b25729 | 3314 | return 1; |
4855022a JP |
3315 | } |
3316 | ||
a09a6e23 PZ |
3317 | visited = VISITED_BRANCH << state.uaccess; |
3318 | if (insn->visited & VISITED_BRANCH_MASK) { | |
e7c0219b | 3319 | if (!insn->hint && !insn_cfi_match(insn, &state.cfi)) |
dcc914f4 | 3320 | return 1; |
dcc914f4 | 3321 | |
882a0db9 | 3322 | if (insn->visited & visited) |
ea24213d | 3323 | return 0; |
8b946cc3 PZ |
3324 | } else { |
3325 | nr_insns_visited++; | |
dcc914f4 JP |
3326 | } |
3327 | ||
c4a33939 PZ |
3328 | if (state.noinstr) |
3329 | state.instr += insn->instr; | |
3330 | ||
8b946cc3 PZ |
3331 | if (insn->hint) { |
3332 | state.cfi = *insn->cfi; | |
3333 | } else { | |
3334 | /* XXX track if we actually changed state.cfi */ | |
3335 | ||
3336 | if (prev_insn && !cficmp(prev_insn->cfi, &state.cfi)) { | |
3337 | insn->cfi = prev_insn->cfi; | |
3338 | nr_cfi_reused++; | |
3339 | } else { | |
3340 | insn->cfi = cfi_hash_find_or_add(&state.cfi); | |
3341 | } | |
3342 | } | |
dcc914f4 | 3343 | |
882a0db9 | 3344 | insn->visited |= visited; |
baa41469 | 3345 | |
c9c324dc JP |
3346 | if (propagate_alt_cfi(file, insn)) |
3347 | return 1; | |
3348 | ||
7117f16b | 3349 | if (!insn->ignore_alts && !list_empty(&insn->alts)) { |
764eef4b PZ |
3350 | bool skip_orig = false; |
3351 | ||
a845c7cf | 3352 | list_for_each_entry(alt, &insn->alts, list) { |
764eef4b PZ |
3353 | if (alt->skip_orig) |
3354 | skip_orig = true; | |
3355 | ||
c705cecc | 3356 | ret = validate_branch(file, func, alt->insn, state); |
7697eee3 | 3357 | if (ret) { |
2daf7fab | 3358 | if (opts.backtrace) |
7697eee3 PZ |
3359 | BT_FUNC("(alt)", insn); |
3360 | return ret; | |
3361 | } | |
a845c7cf | 3362 | } |
764eef4b PZ |
3363 | |
3364 | if (skip_orig) | |
3365 | return 0; | |
dcc914f4 JP |
3366 | } |
3367 | ||
d54dba41 | 3368 | if (handle_insn_ops(insn, next_insn, &state)) |
60041bcd PZ |
3369 | return 1; |
3370 | ||
dcc914f4 JP |
3371 | switch (insn->type) { |
3372 | ||
dcc914f4 | 3373 | case INSN_RETURN: |
a92e92d1 | 3374 | return validate_return(func, insn, &state); |
dcc914f4 JP |
3375 | |
3376 | case INSN_CALL: | |
ea24213d | 3377 | case INSN_CALL_DYNAMIC: |
db2b0c5d | 3378 | ret = validate_call(file, insn, &state); |
ea24213d PZ |
3379 | if (ret) |
3380 | return ret; | |
dcc914f4 | 3381 | |
72064474 | 3382 | if (opts.stackval && func && !is_fentry_call(insn) && |
c9bab22b | 3383 | !has_valid_stack_frame(&state)) { |
dcc914f4 JP |
3384 | WARN_FUNC("call without frame pointer save/setup", |
3385 | sec, insn->offset); | |
3386 | return 1; | |
3387 | } | |
c9bab22b | 3388 | |
0e5b613b | 3389 | if (insn->dead_end) |
c9bab22b JP |
3390 | return 0; |
3391 | ||
dcc914f4 JP |
3392 | break; |
3393 | ||
3394 | case INSN_JUMP_CONDITIONAL: | |
3395 | case INSN_JUMP_UNCONDITIONAL: | |
ecf11ba4 | 3396 | if (is_sibling_call(insn)) { |
db2b0c5d | 3397 | ret = validate_sibling_call(file, insn, &state); |
dcc914f4 | 3398 | if (ret) |
54262aa2 | 3399 | return ret; |
4855022a | 3400 | |
0c1ddd33 | 3401 | } else if (insn->jump_dest) { |
c705cecc JP |
3402 | ret = validate_branch(file, func, |
3403 | insn->jump_dest, state); | |
7697eee3 | 3404 | if (ret) { |
2daf7fab | 3405 | if (opts.backtrace) |
7697eee3 PZ |
3406 | BT_FUNC("(branch)", insn); |
3407 | return ret; | |
3408 | } | |
4855022a | 3409 | } |
dcc914f4 JP |
3410 | |
3411 | if (insn->type == INSN_JUMP_UNCONDITIONAL) | |
3412 | return 0; | |
3413 | ||
3414 | break; | |
3415 | ||
3416 | case INSN_JUMP_DYNAMIC: | |
b68b9907 | 3417 | case INSN_JUMP_DYNAMIC_CONDITIONAL: |
ecf11ba4 | 3418 | if (is_sibling_call(insn)) { |
db2b0c5d | 3419 | ret = validate_sibling_call(file, insn, &state); |
54262aa2 PZ |
3420 | if (ret) |
3421 | return ret; | |
dcc914f4 JP |
3422 | } |
3423 | ||
b68b9907 JP |
3424 | if (insn->type == INSN_JUMP_DYNAMIC) |
3425 | return 0; | |
3426 | ||
3427 | break; | |
dcc914f4 | 3428 | |
39358a03 JP |
3429 | case INSN_CONTEXT_SWITCH: |
3430 | if (func && (!next_insn || !next_insn->hint)) { | |
3431 | WARN_FUNC("unsupported instruction in callable function", | |
3432 | sec, insn->offset); | |
3433 | return 1; | |
3434 | } | |
3435 | return 0; | |
3436 | ||
ea24213d PZ |
3437 | case INSN_STAC: |
3438 | if (state.uaccess) { | |
3439 | WARN_FUNC("recursive UACCESS enable", sec, insn->offset); | |
3440 | return 1; | |
3441 | } | |
3442 | ||
3443 | state.uaccess = true; | |
3444 | break; | |
3445 | ||
3446 | case INSN_CLAC: | |
c705cecc | 3447 | if (!state.uaccess && func) { |
ea24213d PZ |
3448 | WARN_FUNC("redundant UACCESS disable", sec, insn->offset); |
3449 | return 1; | |
3450 | } | |
3451 | ||
3452 | if (func_uaccess_safe(func) && !state.uaccess_stack) { | |
3453 | WARN_FUNC("UACCESS-safe disables UACCESS", sec, insn->offset); | |
3454 | return 1; | |
3455 | } | |
3456 | ||
3457 | state.uaccess = false; | |
baa41469 JP |
3458 | break; |
3459 | ||
2f0f9e9a | 3460 | case INSN_STD: |
6f567c93 | 3461 | if (state.df) { |
2f0f9e9a | 3462 | WARN_FUNC("recursive STD", sec, insn->offset); |
6f567c93 JP |
3463 | return 1; |
3464 | } | |
2f0f9e9a PZ |
3465 | |
3466 | state.df = true; | |
3467 | break; | |
3468 | ||
3469 | case INSN_CLD: | |
6f567c93 | 3470 | if (!state.df && func) { |
2f0f9e9a | 3471 | WARN_FUNC("redundant CLD", sec, insn->offset); |
6f567c93 JP |
3472 | return 1; |
3473 | } | |
2f0f9e9a PZ |
3474 | |
3475 | state.df = false; | |
baa41469 JP |
3476 | break; |
3477 | ||
dcc914f4 JP |
3478 | default: |
3479 | break; | |
3480 | } | |
3481 | ||
3482 | if (insn->dead_end) | |
3483 | return 0; | |
3484 | ||
00d96180 | 3485 | if (!next_insn) { |
e7c0219b | 3486 | if (state.cfi.cfa.base == CFI_UNDEFINED) |
00d96180 | 3487 | return 0; |
dcc914f4 JP |
3488 | WARN("%s: unexpected end of section", sec->name); |
3489 | return 1; | |
3490 | } | |
00d96180 | 3491 | |
8b946cc3 | 3492 | prev_insn = insn; |
00d96180 | 3493 | insn = next_insn; |
dcc914f4 JP |
3494 | } |
3495 | ||
3496 | return 0; | |
3497 | } | |
3498 | ||
932f8e98 | 3499 | static int validate_unwind_hints(struct objtool_file *file, struct section *sec) |
39358a03 JP |
3500 | { |
3501 | struct instruction *insn; | |
39358a03 | 3502 | struct insn_state state; |
932f8e98 | 3503 | int ret, warnings = 0; |
39358a03 JP |
3504 | |
3505 | if (!file->hints) | |
3506 | return 0; | |
3507 | ||
753da417 | 3508 | init_insn_state(file, &state, sec); |
39358a03 | 3509 | |
932f8e98 PZ |
3510 | if (sec) { |
3511 | insn = find_insn(file, sec, 0); | |
3512 | if (!insn) | |
3513 | return 0; | |
3514 | } else { | |
3515 | insn = list_first_entry(&file->insn_list, typeof(*insn), list); | |
3516 | } | |
3517 | ||
3518 | while (&insn->list != &file->insn_list && (!sec || insn->sec == sec)) { | |
5b284b19 | 3519 | if (insn->hint && !insn->visited && !insn->ignore) { |
c705cecc | 3520 | ret = validate_branch(file, insn->func, insn, state); |
2daf7fab | 3521 | if (ret && opts.backtrace) |
7697eee3 | 3522 | BT_FUNC("<=== (hint)", insn); |
39358a03 JP |
3523 | warnings += ret; |
3524 | } | |
932f8e98 PZ |
3525 | |
3526 | insn = list_next_entry(insn, list); | |
39358a03 JP |
3527 | } |
3528 | ||
3529 | return warnings; | |
3530 | } | |
3531 | ||
a09a6e23 PZ |
3532 | /* |
3533 | * Validate rethunk entry constraint: must untrain RET before the first RET. | |
3534 | * | |
3535 | * Follow every branch (intra-function) and ensure ANNOTATE_UNRET_END comes | |
3536 | * before an actual RET instruction. | |
3537 | */ | |
3538 | static int validate_entry(struct objtool_file *file, struct instruction *insn) | |
3539 | { | |
3540 | struct instruction *next, *dest; | |
3541 | int ret, warnings = 0; | |
3542 | ||
3543 | for (;;) { | |
3544 | next = next_insn_to_validate(file, insn); | |
3545 | ||
3546 | if (insn->visited & VISITED_ENTRY) | |
3547 | return 0; | |
3548 | ||
3549 | insn->visited |= VISITED_ENTRY; | |
3550 | ||
3551 | if (!insn->ignore_alts && !list_empty(&insn->alts)) { | |
3552 | struct alternative *alt; | |
3553 | bool skip_orig = false; | |
3554 | ||
3555 | list_for_each_entry(alt, &insn->alts, list) { | |
3556 | if (alt->skip_orig) | |
3557 | skip_orig = true; | |
3558 | ||
3559 | ret = validate_entry(file, alt->insn); | |
3560 | if (ret) { | |
3561 | if (opts.backtrace) | |
3562 | BT_FUNC("(alt)", insn); | |
3563 | return ret; | |
3564 | } | |
3565 | } | |
3566 | ||
3567 | if (skip_orig) | |
3568 | return 0; | |
3569 | } | |
3570 | ||
3571 | switch (insn->type) { | |
3572 | ||
3573 | case INSN_CALL_DYNAMIC: | |
3574 | case INSN_JUMP_DYNAMIC: | |
3575 | case INSN_JUMP_DYNAMIC_CONDITIONAL: | |
3576 | WARN_FUNC("early indirect call", insn->sec, insn->offset); | |
3577 | return 1; | |
3578 | ||
3579 | case INSN_JUMP_UNCONDITIONAL: | |
3580 | case INSN_JUMP_CONDITIONAL: | |
3581 | if (!is_sibling_call(insn)) { | |
3582 | if (!insn->jump_dest) { | |
3583 | WARN_FUNC("unresolved jump target after linking?!?", | |
3584 | insn->sec, insn->offset); | |
3585 | return -1; | |
3586 | } | |
3587 | ret = validate_entry(file, insn->jump_dest); | |
3588 | if (ret) { | |
3589 | if (opts.backtrace) { | |
3590 | BT_FUNC("(branch%s)", insn, | |
3591 | insn->type == INSN_JUMP_CONDITIONAL ? "-cond" : ""); | |
3592 | } | |
3593 | return ret; | |
3594 | } | |
3595 | ||
3596 | if (insn->type == INSN_JUMP_UNCONDITIONAL) | |
3597 | return 0; | |
3598 | ||
3599 | break; | |
3600 | } | |
3601 | ||
3602 | /* fallthrough */ | |
3603 | case INSN_CALL: | |
3604 | dest = find_insn(file, insn->call_dest->sec, | |
3605 | insn->call_dest->offset); | |
3606 | if (!dest) { | |
3607 | WARN("Unresolved function after linking!?: %s", | |
3608 | insn->call_dest->name); | |
3609 | return -1; | |
3610 | } | |
3611 | ||
3612 | ret = validate_entry(file, dest); | |
3613 | if (ret) { | |
3614 | if (opts.backtrace) | |
3615 | BT_FUNC("(call)", insn); | |
3616 | return ret; | |
3617 | } | |
3618 | /* | |
3619 | * If a call returns without error, it must have seen UNTRAIN_RET. | |
3620 | * Therefore any non-error return is a success. | |
3621 | */ | |
3622 | return 0; | |
3623 | ||
3624 | case INSN_RETURN: | |
3625 | WARN_FUNC("RET before UNTRAIN", insn->sec, insn->offset); | |
3626 | return 1; | |
3627 | ||
3628 | case INSN_NOP: | |
3629 | if (insn->retpoline_safe) | |
3630 | return 0; | |
3631 | break; | |
3632 | ||
3633 | default: | |
3634 | break; | |
3635 | } | |
3636 | ||
3637 | if (!next) { | |
3638 | WARN_FUNC("teh end!", insn->sec, insn->offset); | |
3639 | return -1; | |
3640 | } | |
3641 | insn = next; | |
3642 | } | |
3643 | ||
3644 | return warnings; | |
3645 | } | |
3646 | ||
3647 | /* | |
3648 | * Validate that all branches starting at 'insn->entry' encounter UNRET_END | |
3649 | * before RET. | |
3650 | */ | |
3651 | static int validate_unret(struct objtool_file *file) | |
3652 | { | |
3653 | struct instruction *insn; | |
3654 | int ret, warnings = 0; | |
3655 | ||
3656 | for_each_insn(file, insn) { | |
3657 | if (!insn->entry) | |
3658 | continue; | |
3659 | ||
3660 | ret = validate_entry(file, insn); | |
3661 | if (ret < 0) { | |
3662 | WARN_FUNC("Failed UNRET validation", insn->sec, insn->offset); | |
3663 | return ret; | |
3664 | } | |
3665 | warnings += ret; | |
3666 | } | |
3667 | ||
3668 | return warnings; | |
3669 | } | |
3670 | ||
b5bc2231 PZ |
3671 | static int validate_retpoline(struct objtool_file *file) |
3672 | { | |
3673 | struct instruction *insn; | |
3674 | int warnings = 0; | |
3675 | ||
3676 | for_each_insn(file, insn) { | |
3677 | if (insn->type != INSN_JUMP_DYNAMIC && | |
9bb2ec60 PZ |
3678 | insn->type != INSN_CALL_DYNAMIC && |
3679 | insn->type != INSN_RETURN) | |
b5bc2231 PZ |
3680 | continue; |
3681 | ||
3682 | if (insn->retpoline_safe) | |
3683 | continue; | |
3684 | ||
ca41b97e PZ |
3685 | /* |
3686 | * .init.text code is ran before userspace and thus doesn't | |
3687 | * strictly need retpolines, except for modules which are | |
3688 | * loaded late, they very much do need retpoline in their | |
3689 | * .init.text | |
3690 | */ | |
2daf7fab | 3691 | if (!strcmp(insn->sec->name, ".init.text") && !opts.module) |
ca41b97e PZ |
3692 | continue; |
3693 | ||
9bb2ec60 PZ |
3694 | if (insn->type == INSN_RETURN) { |
3695 | WARN_FUNC("'naked' return found in RETPOLINE build", | |
3696 | insn->sec, insn->offset); | |
3697 | } else { | |
3698 | WARN_FUNC("indirect %s found in RETPOLINE build", | |
3699 | insn->sec, insn->offset, | |
3700 | insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call"); | |
3701 | } | |
b5bc2231 PZ |
3702 | |
3703 | warnings++; | |
3704 | } | |
3705 | ||
3706 | return warnings; | |
3707 | } | |
3708 | ||
dcc914f4 JP |
3709 | static bool is_kasan_insn(struct instruction *insn) |
3710 | { | |
3711 | return (insn->type == INSN_CALL && | |
3712 | !strcmp(insn->call_dest->name, "__asan_handle_no_return")); | |
3713 | } | |
3714 | ||
3715 | static bool is_ubsan_insn(struct instruction *insn) | |
3716 | { | |
3717 | return (insn->type == INSN_CALL && | |
3718 | !strcmp(insn->call_dest->name, | |
3719 | "__ubsan_handle_builtin_unreachable")); | |
3720 | } | |
3721 | ||
14db1f0a | 3722 | static bool ignore_unreachable_insn(struct objtool_file *file, struct instruction *insn) |
dcc914f4 JP |
3723 | { |
3724 | int i; | |
14db1f0a | 3725 | struct instruction *prev_insn; |
dcc914f4 | 3726 | |
1ffbe4e9 | 3727 | if (insn->ignore || insn->type == INSN_NOP || insn->type == INSN_TRAP) |
baa41469 JP |
3728 | return true; |
3729 | ||
3730 | /* | |
82a8954a | 3731 | * Ignore alternative replacement instructions. This can happen |
0e2bb2bc | 3732 | * when a whitelisted function uses one of the ALTERNATIVE macros. |
baa41469 | 3733 | */ |
82a8954a | 3734 | if (!strcmp(insn->sec->name, ".altinstr_replacement") || |
0e2bb2bc | 3735 | !strcmp(insn->sec->name, ".altinstr_aux")) |
dcc914f4 JP |
3736 | return true; |
3737 | ||
4adb2368 | 3738 | /* |
753da417 | 3739 | * Whole archive runs might encounter dead code from weak symbols. |
4adb2368 PZ |
3740 | * This is where the linker will have dropped the weak symbol in |
3741 | * favour of a regular symbol, but leaves the code in place. | |
3742 | * | |
3743 | * In this case we'll find a piece of code (whole function) that is not | |
3744 | * covered by a !section symbol. Ignore them. | |
3745 | */ | |
753da417 | 3746 | if (opts.link && !insn->func) { |
4adb2368 PZ |
3747 | int size = find_symbol_hole_containing(insn->sec, insn->offset); |
3748 | unsigned long end = insn->offset + size; | |
3749 | ||
3750 | if (!size) /* not a hole */ | |
3751 | return false; | |
3752 | ||
3753 | if (size < 0) /* hole until the end */ | |
3754 | return true; | |
3755 | ||
3756 | sec_for_each_insn_continue(file, insn) { | |
3757 | /* | |
3758 | * If we reach a visited instruction at or before the | |
3759 | * end of the hole, ignore the unreachable. | |
3760 | */ | |
3761 | if (insn->visited) | |
3762 | return true; | |
3763 | ||
3764 | if (insn->offset >= end) | |
3765 | break; | |
3766 | ||
3767 | /* | |
3768 | * If this hole jumps to a .cold function, mark it ignore too. | |
3769 | */ | |
3770 | if (insn->jump_dest && insn->jump_dest->func && | |
3771 | strstr(insn->jump_dest->func->name, ".cold")) { | |
3772 | struct instruction *dest = insn->jump_dest; | |
3773 | func_for_each_insn(file, dest->func, dest) | |
3774 | dest->ignore = true; | |
3775 | } | |
3776 | } | |
3777 | ||
3778 | return false; | |
3779 | } | |
3780 | ||
bd841d61 JP |
3781 | if (!insn->func) |
3782 | return false; | |
3783 | ||
2105a927 PZ |
3784 | if (insn->func->static_call_tramp) |
3785 | return true; | |
3786 | ||
bd841d61 JP |
3787 | /* |
3788 | * CONFIG_UBSAN_TRAP inserts a UD2 when it sees | |
3789 | * __builtin_unreachable(). The BUG() macro has an unreachable() after | |
3790 | * the UD2, which causes GCC's undefined trap logic to emit another UD2 | |
3791 | * (or occasionally a JMP to UD2). | |
14db1f0a IH |
3792 | * |
3793 | * It may also insert a UD2 after calling a __noreturn function. | |
bd841d61 | 3794 | */ |
14db1f0a IH |
3795 | prev_insn = list_prev_entry(insn, list); |
3796 | if ((prev_insn->dead_end || dead_end_function(file, prev_insn->call_dest)) && | |
bd841d61 JP |
3797 | (insn->type == INSN_BUG || |
3798 | (insn->type == INSN_JUMP_UNCONDITIONAL && | |
3799 | insn->jump_dest && insn->jump_dest->type == INSN_BUG))) | |
3800 | return true; | |
3801 | ||
dcc914f4 JP |
3802 | /* |
3803 | * Check if this (or a subsequent) instruction is related to | |
3804 | * CONFIG_UBSAN or CONFIG_KASAN. | |
3805 | * | |
3806 | * End the search at 5 instructions to avoid going into the weeds. | |
3807 | */ | |
3808 | for (i = 0; i < 5; i++) { | |
3809 | ||
3810 | if (is_kasan_insn(insn) || is_ubsan_insn(insn)) | |
3811 | return true; | |
3812 | ||
fe24e271 JP |
3813 | if (insn->type == INSN_JUMP_UNCONDITIONAL) { |
3814 | if (insn->jump_dest && | |
3815 | insn->jump_dest->func == insn->func) { | |
3816 | insn = insn->jump_dest; | |
3817 | continue; | |
3818 | } | |
3819 | ||
3820 | break; | |
dcc914f4 JP |
3821 | } |
3822 | ||
baa41469 | 3823 | if (insn->offset + insn->len >= insn->func->offset + insn->func->len) |
dcc914f4 | 3824 | break; |
fe24e271 | 3825 | |
dcc914f4 JP |
3826 | insn = list_next_entry(insn, list); |
3827 | } | |
3828 | ||
3829 | return false; | |
3830 | } | |
3831 | ||
4b5e2e7f PZ |
3832 | static int validate_symbol(struct objtool_file *file, struct section *sec, |
3833 | struct symbol *sym, struct insn_state *state) | |
dcc914f4 | 3834 | { |
dcc914f4 | 3835 | struct instruction *insn; |
4b5e2e7f PZ |
3836 | int ret; |
3837 | ||
3838 | if (!sym->len) { | |
3839 | WARN("%s() is missing an ELF size annotation", sym->name); | |
3840 | return 1; | |
3841 | } | |
3842 | ||
3843 | if (sym->pfunc != sym || sym->alias != sym) | |
3844 | return 0; | |
3845 | ||
3846 | insn = find_insn(file, sec, sym->offset); | |
3847 | if (!insn || insn->ignore || insn->visited) | |
3848 | return 0; | |
3849 | ||
3850 | state->uaccess = sym->uaccess_safe; | |
3851 | ||
3852 | ret = validate_branch(file, insn->func, insn, *state); | |
2daf7fab | 3853 | if (ret && opts.backtrace) |
4b5e2e7f PZ |
3854 | BT_FUNC("<=== (sym)", insn); |
3855 | return ret; | |
3856 | } | |
3857 | ||
3858 | static int validate_section(struct objtool_file *file, struct section *sec) | |
3859 | { | |
baa41469 | 3860 | struct insn_state state; |
4b5e2e7f PZ |
3861 | struct symbol *func; |
3862 | int warnings = 0; | |
dcc914f4 | 3863 | |
350994bf PZ |
3864 | list_for_each_entry(func, &sec->symbol_list, list) { |
3865 | if (func->type != STT_FUNC) | |
3866 | continue; | |
e10cd8fe | 3867 | |
753da417 | 3868 | init_insn_state(file, &state, sec); |
b735bd3e | 3869 | set_func_state(&state.cfi); |
0699e551 | 3870 | |
4b5e2e7f | 3871 | warnings += validate_symbol(file, sec, func, &state); |
dcc914f4 JP |
3872 | } |
3873 | ||
dcc914f4 JP |
3874 | return warnings; |
3875 | } | |
3876 | ||
753da417 | 3877 | static int validate_noinstr_sections(struct objtool_file *file) |
c4a33939 PZ |
3878 | { |
3879 | struct section *sec; | |
932f8e98 | 3880 | int warnings = 0; |
c4a33939 PZ |
3881 | |
3882 | sec = find_section_by_name(file->elf, ".noinstr.text"); | |
0cc9ac8d TG |
3883 | if (sec) { |
3884 | warnings += validate_section(file, sec); | |
3885 | warnings += validate_unwind_hints(file, sec); | |
3886 | } | |
c4a33939 | 3887 | |
0cc9ac8d TG |
3888 | sec = find_section_by_name(file->elf, ".entry.text"); |
3889 | if (sec) { | |
3890 | warnings += validate_section(file, sec); | |
3891 | warnings += validate_unwind_hints(file, sec); | |
3892 | } | |
932f8e98 PZ |
3893 | |
3894 | return warnings; | |
c4a33939 PZ |
3895 | } |
3896 | ||
350994bf PZ |
3897 | static int validate_functions(struct objtool_file *file) |
3898 | { | |
3899 | struct section *sec; | |
3900 | int warnings = 0; | |
3901 | ||
da837bd6 PZ |
3902 | for_each_sec(file, sec) { |
3903 | if (!(sec->sh.sh_flags & SHF_EXECINSTR)) | |
3904 | continue; | |
3905 | ||
350994bf | 3906 | warnings += validate_section(file, sec); |
da837bd6 | 3907 | } |
350994bf PZ |
3908 | |
3909 | return warnings; | |
3910 | } | |
3911 | ||
3c6f9f77 | 3912 | static void mark_endbr_used(struct instruction *insn) |
08f87a93 | 3913 | { |
3c6f9f77 JP |
3914 | if (!list_empty(&insn->call_node)) |
3915 | list_del_init(&insn->call_node); | |
3916 | } | |
3917 | ||
3918 | static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn) | |
3919 | { | |
3920 | struct instruction *dest; | |
08f87a93 | 3921 | struct reloc *reloc; |
3c6f9f77 JP |
3922 | unsigned long off; |
3923 | int warnings = 0; | |
08f87a93 | 3924 | |
3c6f9f77 JP |
3925 | /* |
3926 | * Looking for function pointer load relocations. Ignore | |
3927 | * direct/indirect branches: | |
3928 | */ | |
3929 | switch (insn->type) { | |
3930 | case INSN_CALL: | |
3931 | case INSN_CALL_DYNAMIC: | |
3932 | case INSN_JUMP_CONDITIONAL: | |
3933 | case INSN_JUMP_UNCONDITIONAL: | |
3934 | case INSN_JUMP_DYNAMIC: | |
3935 | case INSN_JUMP_DYNAMIC_CONDITIONAL: | |
3936 | case INSN_RETURN: | |
3937 | case INSN_NOP: | |
3938 | return 0; | |
3939 | default: | |
3940 | break; | |
3941 | } | |
08f87a93 | 3942 | |
3c6f9f77 JP |
3943 | for (reloc = insn_reloc(file, insn); |
3944 | reloc; | |
3945 | reloc = find_reloc_by_dest_range(file->elf, insn->sec, | |
3946 | reloc->offset + 1, | |
3947 | (insn->offset + insn->len) - (reloc->offset + 1))) { | |
08f87a93 | 3948 | |
3c6f9f77 JP |
3949 | /* |
3950 | * static_call_update() references the trampoline, which | |
3951 | * doesn't have (or need) ENDBR. Skip warning in that case. | |
3952 | */ | |
3953 | if (reloc->sym->static_call_tramp) | |
08f87a93 PZ |
3954 | continue; |
3955 | ||
3c6f9f77 JP |
3956 | off = reloc->sym->offset; |
3957 | if (reloc->type == R_X86_64_PC32 || reloc->type == R_X86_64_PLT32) | |
3958 | off += arch_dest_reloc_offset(reloc->addend); | |
3959 | else | |
3960 | off += reloc->addend; | |
3961 | ||
3962 | dest = find_insn(file, reloc->sym->sec, off); | |
3963 | if (!dest) | |
08f87a93 PZ |
3964 | continue; |
3965 | ||
3c6f9f77 JP |
3966 | if (dest->type == INSN_ENDBR) { |
3967 | mark_endbr_used(dest); | |
08f87a93 | 3968 | continue; |
3c6f9f77 | 3969 | } |
08f87a93 | 3970 | |
3c6f9f77 JP |
3971 | if (dest->func && dest->func == insn->func) { |
3972 | /* | |
3973 | * Anything from->to self is either _THIS_IP_ or | |
3974 | * IRET-to-self. | |
3975 | * | |
3976 | * There is no sane way to annotate _THIS_IP_ since the | |
3977 | * compiler treats the relocation as a constant and is | |
3978 | * happy to fold in offsets, skewing any annotation we | |
3979 | * do, leading to vast amounts of false-positives. | |
3980 | * | |
3981 | * There's also compiler generated _THIS_IP_ through | |
3982 | * KCOV and such which we have no hope of annotating. | |
3983 | * | |
3984 | * As such, blanket accept self-references without | |
3985 | * issue. | |
3986 | */ | |
08f87a93 | 3987 | continue; |
3c6f9f77 | 3988 | } |
08f87a93 | 3989 | |
3c6f9f77 | 3990 | if (dest->noendbr) |
08f87a93 PZ |
3991 | continue; |
3992 | ||
3c6f9f77 JP |
3993 | WARN_FUNC("relocation to !ENDBR: %s", |
3994 | insn->sec, insn->offset, | |
3995 | offstr(dest->sec, dest->offset)); | |
3996 | ||
3997 | warnings++; | |
3998 | } | |
3999 | ||
4000 | return warnings; | |
4001 | } | |
4002 | ||
4003 | static int validate_ibt_data_reloc(struct objtool_file *file, | |
4004 | struct reloc *reloc) | |
4005 | { | |
4006 | struct instruction *dest; | |
4007 | ||
4008 | dest = find_insn(file, reloc->sym->sec, | |
4009 | reloc->sym->offset + reloc->addend); | |
4010 | if (!dest) | |
4011 | return 0; | |
4012 | ||
4013 | if (dest->type == INSN_ENDBR) { | |
4014 | mark_endbr_used(dest); | |
4015 | return 0; | |
4016 | } | |
4017 | ||
4018 | if (dest->noendbr) | |
4019 | return 0; | |
4020 | ||
4021 | WARN_FUNC("data relocation to !ENDBR: %s", | |
4022 | reloc->sec->base, reloc->offset, | |
4023 | offstr(dest->sec, dest->offset)); | |
4024 | ||
4025 | return 1; | |
4026 | } | |
4027 | ||
4028 | /* | |
4029 | * Validate IBT rules and remove used ENDBR instructions from the seal list. | |
4030 | * Unused ENDBR instructions will be annotated for sealing (i.e., replaced with | |
4031 | * NOPs) later, in create_ibt_endbr_seal_sections(). | |
4032 | */ | |
4033 | static int validate_ibt(struct objtool_file *file) | |
4034 | { | |
4035 | struct section *sec; | |
4036 | struct reloc *reloc; | |
4037 | struct instruction *insn; | |
4038 | int warnings = 0; | |
4039 | ||
4040 | for_each_insn(file, insn) | |
4041 | warnings += validate_ibt_insn(file, insn); | |
4042 | ||
4043 | for_each_sec(file, sec) { | |
4044 | ||
4045 | /* Already done by validate_ibt_insn() */ | |
4046 | if (sec->sh.sh_flags & SHF_EXECINSTR) | |
08f87a93 PZ |
4047 | continue; |
4048 | ||
3c6f9f77 JP |
4049 | if (!sec->reloc) |
4050 | continue; | |
08f87a93 | 4051 | |
3c6f9f77 JP |
4052 | /* |
4053 | * These sections can reference text addresses, but not with | |
4054 | * the intent to indirect branch to them. | |
4055 | */ | |
4056 | if (!strncmp(sec->name, ".discard", 8) || | |
4057 | !strncmp(sec->name, ".debug", 6) || | |
4058 | !strcmp(sec->name, ".altinstructions") || | |
4059 | !strcmp(sec->name, ".ibt_endbr_seal") || | |
4060 | !strcmp(sec->name, ".orc_unwind_ip") || | |
4061 | !strcmp(sec->name, ".parainstructions") || | |
4062 | !strcmp(sec->name, ".retpoline_sites") || | |
4063 | !strcmp(sec->name, ".smp_locks") || | |
4064 | !strcmp(sec->name, ".static_call_sites") || | |
4065 | !strcmp(sec->name, "_error_injection_whitelist") || | |
4066 | !strcmp(sec->name, "_kprobe_blacklist") || | |
4067 | !strcmp(sec->name, "__bug_table") || | |
4068 | !strcmp(sec->name, "__ex_table") || | |
4069 | !strcmp(sec->name, "__jump_table") || | |
4070 | !strcmp(sec->name, "__mcount_loc") || | |
4071 | !strcmp(sec->name, "__tracepoints")) | |
4072 | continue; | |
08f87a93 | 4073 | |
3c6f9f77 JP |
4074 | list_for_each_entry(reloc, &sec->reloc->reloc_list, list) |
4075 | warnings += validate_ibt_data_reloc(file, reloc); | |
08f87a93 PZ |
4076 | } |
4077 | ||
3c6f9f77 | 4078 | return warnings; |
08f87a93 PZ |
4079 | } |
4080 | ||
c2bdd61c JP |
4081 | static int validate_sls(struct objtool_file *file) |
4082 | { | |
4083 | struct instruction *insn, *next_insn; | |
4084 | int warnings = 0; | |
4085 | ||
4086 | for_each_insn(file, insn) { | |
4087 | next_insn = next_insn_same_sec(file, insn); | |
4088 | ||
4089 | if (insn->retpoline_safe) | |
4090 | continue; | |
4091 | ||
4092 | switch (insn->type) { | |
4093 | case INSN_RETURN: | |
4094 | if (!next_insn || next_insn->type != INSN_TRAP) { | |
4095 | WARN_FUNC("missing int3 after ret", | |
4096 | insn->sec, insn->offset); | |
4097 | warnings++; | |
4098 | } | |
4099 | ||
4100 | break; | |
4101 | case INSN_JUMP_DYNAMIC: | |
4102 | if (!next_insn || next_insn->type != INSN_TRAP) { | |
4103 | WARN_FUNC("missing int3 after indirect jump", | |
4104 | insn->sec, insn->offset); | |
4105 | warnings++; | |
4106 | } | |
4107 | break; | |
4108 | default: | |
4109 | break; | |
4110 | } | |
4111 | } | |
4112 | ||
4113 | return warnings; | |
4114 | } | |
4115 | ||
baa41469 | 4116 | static int validate_reachable_instructions(struct objtool_file *file) |
dcc914f4 JP |
4117 | { |
4118 | struct instruction *insn; | |
baa41469 JP |
4119 | |
4120 | if (file->ignore_unreachables) | |
4121 | return 0; | |
dcc914f4 JP |
4122 | |
4123 | for_each_insn(file, insn) { | |
14db1f0a | 4124 | if (insn->visited || ignore_unreachable_insn(file, insn)) |
baa41469 JP |
4125 | continue; |
4126 | ||
baa41469 JP |
4127 | WARN_FUNC("unreachable instruction", insn->sec, insn->offset); |
4128 | return 1; | |
dcc914f4 JP |
4129 | } |
4130 | ||
baa41469 | 4131 | return 0; |
dcc914f4 JP |
4132 | } |
4133 | ||
d44becb9 | 4134 | int check(struct objtool_file *file) |
dcc914f4 | 4135 | { |
dcc914f4 JP |
4136 | int ret, warnings = 0; |
4137 | ||
baa41469 | 4138 | arch_initial_func_cfi_state(&initial_func_cfi); |
8b946cc3 PZ |
4139 | init_cfi_state(&init_cfi); |
4140 | init_cfi_state(&func_cfi); | |
4141 | set_func_state(&func_cfi); | |
4142 | ||
4143 | if (!cfi_hash_alloc(1UL << (file->elf->symbol_bits - 3))) | |
4144 | goto out; | |
4145 | ||
4146 | cfi_hash_add(&init_cfi); | |
4147 | cfi_hash_add(&func_cfi); | |
baa41469 | 4148 | |
6545eb03 | 4149 | ret = decode_sections(file); |
dcc914f4 JP |
4150 | if (ret < 0) |
4151 | goto out; | |
8b946cc3 | 4152 | |
dcc914f4 JP |
4153 | warnings += ret; |
4154 | ||
6545eb03 | 4155 | if (list_empty(&file->insn_list)) |
dcc914f4 | 4156 | goto out; |
dcc914f4 | 4157 | |
2daf7fab | 4158 | if (opts.retpoline) { |
6545eb03 | 4159 | ret = validate_retpoline(file); |
b5bc2231 PZ |
4160 | if (ret < 0) |
4161 | return ret; | |
4162 | warnings += ret; | |
4163 | } | |
4164 | ||
c2bdd61c | 4165 | if (opts.stackval || opts.orc || opts.uaccess) { |
7dce6204 JP |
4166 | ret = validate_functions(file); |
4167 | if (ret < 0) | |
4168 | goto out; | |
4169 | warnings += ret; | |
39358a03 | 4170 | |
7dce6204 | 4171 | ret = validate_unwind_hints(file, NULL); |
08f87a93 PZ |
4172 | if (ret < 0) |
4173 | goto out; | |
4174 | warnings += ret; | |
7dce6204 JP |
4175 | |
4176 | if (!warnings) { | |
4177 | ret = validate_reachable_instructions(file); | |
4178 | if (ret < 0) | |
4179 | goto out; | |
4180 | warnings += ret; | |
4181 | } | |
753da417 JP |
4182 | |
4183 | } else if (opts.noinstr) { | |
4184 | ret = validate_noinstr_sections(file); | |
4185 | if (ret < 0) | |
4186 | goto out; | |
4187 | warnings += ret; | |
08f87a93 PZ |
4188 | } |
4189 | ||
a09a6e23 PZ |
4190 | if (opts.unret) { |
4191 | /* | |
4192 | * Must be after validate_branch() and friends, it plays | |
4193 | * further games with insn->visited. | |
4194 | */ | |
4195 | ret = validate_unret(file); | |
4196 | if (ret < 0) | |
4197 | return ret; | |
4198 | warnings += ret; | |
4199 | } | |
4200 | ||
7dce6204 JP |
4201 | if (opts.ibt) { |
4202 | ret = validate_ibt(file); | |
baa41469 JP |
4203 | if (ret < 0) |
4204 | goto out; | |
c2bdd61c JP |
4205 | warnings += ret; |
4206 | } | |
4207 | ||
4208 | if (opts.sls) { | |
4209 | ret = validate_sls(file); | |
4210 | if (ret < 0) | |
4211 | goto out; | |
baa41469 JP |
4212 | warnings += ret; |
4213 | } | |
4214 | ||
26e17689 JP |
4215 | if (opts.static_call) { |
4216 | ret = create_static_call_sections(file); | |
4217 | if (ret < 0) | |
4218 | goto out; | |
4219 | warnings += ret; | |
4220 | } | |
1e7e4788 | 4221 | |
2daf7fab | 4222 | if (opts.retpoline) { |
134ab5bd PZ |
4223 | ret = create_retpoline_sites_sections(file); |
4224 | if (ret < 0) | |
4225 | goto out; | |
4226 | warnings += ret; | |
d9e9d230 PZ |
4227 | |
4228 | ret = create_return_sites_sections(file); | |
4229 | if (ret < 0) | |
4230 | goto out; | |
4231 | warnings += ret; | |
134ab5bd PZ |
4232 | } |
4233 | ||
2daf7fab | 4234 | if (opts.mcount) { |
99d00215 PZ |
4235 | ret = create_mcount_loc_sections(file); |
4236 | if (ret < 0) | |
4237 | goto out; | |
4238 | warnings += ret; | |
4239 | } | |
4240 | ||
2daf7fab | 4241 | if (opts.ibt) { |
89bc853e PZ |
4242 | ret = create_ibt_endbr_seal_sections(file); |
4243 | if (ret < 0) | |
4244 | goto out; | |
4245 | warnings += ret; | |
4246 | } | |
4247 | ||
b51277eb JP |
4248 | if (opts.orc && !list_empty(&file->insn_list)) { |
4249 | ret = orc_create(file); | |
4250 | if (ret < 0) | |
4251 | goto out; | |
4252 | warnings += ret; | |
4253 | } | |
4254 | ||
4255 | ||
2daf7fab | 4256 | if (opts.stats) { |
8b946cc3 PZ |
4257 | printf("nr_insns_visited: %ld\n", nr_insns_visited); |
4258 | printf("nr_cfi: %ld\n", nr_cfi); | |
4259 | printf("nr_cfi_reused: %ld\n", nr_cfi_reused); | |
4260 | printf("nr_cfi_cache: %ld\n", nr_cfi_cache); | |
4261 | } | |
4262 | ||
dcc914f4 | 4263 | out: |
655cf865 JP |
4264 | /* |
4265 | * For now, don't fail the kernel build on fatal warnings. These | |
4266 | * errors are still fairly common due to the growing matrix of | |
4267 | * supported toolchains and their recent pace of change. | |
4268 | */ | |
dcc914f4 JP |
4269 | return 0; |
4270 | } |