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1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright (C) 2019 Google, Inc. | |
4 | * modified from kernel/gcov/gcc_4_7.c | |
5 | * | |
6 | * This software is licensed under the terms of the GNU General Public | |
7 | * License version 2, as published by the Free Software Foundation, and | |
8 | * may be copied, distributed, and modified under those terms. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * | |
16 | * LLVM uses profiling data that's deliberately similar to GCC, but has a | |
17 | * very different way of exporting that data. LLVM calls llvm_gcov_init() once | |
18 | * per module, and provides a couple of callbacks that we can use to ask for | |
19 | * more data. | |
20 | * | |
21 | * We care about the "writeout" callback, which in turn calls back into | |
22 | * compiler-rt/this module to dump all the gathered coverage data to disk: | |
23 | * | |
24 | * llvm_gcda_start_file() | |
25 | * llvm_gcda_emit_function() | |
26 | * llvm_gcda_emit_arcs() | |
27 | * llvm_gcda_emit_function() | |
28 | * llvm_gcda_emit_arcs() | |
29 | * [... repeats for each function ...] | |
30 | * llvm_gcda_summary_info() | |
31 | * llvm_gcda_end_file() | |
32 | * | |
33 | * This design is much more stateless and unstructured than gcc's, and is | |
34 | * intended to run at process exit. This forces us to keep some local state | |
35 | * about which module we're dealing with at the moment. On the other hand, it | |
36 | * also means we don't depend as much on how LLVM represents profiling data | |
37 | * internally. | |
38 | * | |
39 | * See LLVM's lib/Transforms/Instrumentation/GCOVProfiling.cpp for more | |
40 | * details on how this works, particularly GCOVProfiler::emitProfileArcs(), | |
41 | * GCOVProfiler::insertCounterWriteout(), and | |
42 | * GCOVProfiler::insertFlush(). | |
43 | */ | |
44 | ||
45 | #define pr_fmt(fmt) "gcov: " fmt | |
46 | ||
47 | #include <linux/kernel.h> | |
48 | #include <linux/list.h> | |
49 | #include <linux/printk.h> | |
50 | #include <linux/ratelimit.h> | |
51 | #include <linux/seq_file.h> | |
52 | #include <linux/slab.h> | |
53 | #include <linux/vmalloc.h> | |
54 | #include "gcov.h" | |
55 | ||
56 | typedef void (*llvm_gcov_callback)(void); | |
57 | ||
58 | struct gcov_info { | |
59 | struct list_head head; | |
60 | ||
61 | const char *filename; | |
62 | unsigned int version; | |
63 | u32 checksum; | |
64 | ||
65 | struct list_head functions; | |
66 | }; | |
67 | ||
68 | struct gcov_fn_info { | |
69 | struct list_head head; | |
70 | ||
71 | u32 ident; | |
72 | u32 checksum; | |
73 | u8 use_extra_checksum; | |
74 | u32 cfg_checksum; | |
75 | ||
76 | u32 num_counters; | |
77 | u64 *counters; | |
78 | const char *function_name; | |
79 | }; | |
80 | ||
81 | static struct gcov_info *current_info; | |
82 | ||
83 | static LIST_HEAD(clang_gcov_list); | |
84 | ||
85 | void llvm_gcov_init(llvm_gcov_callback writeout, llvm_gcov_callback flush) | |
86 | { | |
87 | struct gcov_info *info = kzalloc(sizeof(*info), GFP_KERNEL); | |
88 | ||
89 | if (!info) | |
90 | return; | |
91 | ||
92 | INIT_LIST_HEAD(&info->head); | |
93 | INIT_LIST_HEAD(&info->functions); | |
94 | ||
95 | mutex_lock(&gcov_lock); | |
96 | ||
97 | list_add_tail(&info->head, &clang_gcov_list); | |
98 | current_info = info; | |
99 | writeout(); | |
100 | current_info = NULL; | |
101 | if (gcov_events_enabled) | |
102 | gcov_event(GCOV_ADD, info); | |
103 | ||
104 | mutex_unlock(&gcov_lock); | |
105 | } | |
106 | EXPORT_SYMBOL(llvm_gcov_init); | |
107 | ||
108 | void llvm_gcda_start_file(const char *orig_filename, const char version[4], | |
109 | u32 checksum) | |
110 | { | |
111 | current_info->filename = orig_filename; | |
112 | memcpy(¤t_info->version, version, sizeof(current_info->version)); | |
113 | current_info->checksum = checksum; | |
114 | } | |
115 | EXPORT_SYMBOL(llvm_gcda_start_file); | |
116 | ||
117 | void llvm_gcda_emit_function(u32 ident, const char *function_name, | |
118 | u32 func_checksum, u8 use_extra_checksum, u32 cfg_checksum) | |
119 | { | |
120 | struct gcov_fn_info *info = kzalloc(sizeof(*info), GFP_KERNEL); | |
121 | ||
122 | if (!info) | |
123 | return; | |
124 | ||
125 | INIT_LIST_HEAD(&info->head); | |
126 | info->ident = ident; | |
127 | info->checksum = func_checksum; | |
128 | info->use_extra_checksum = use_extra_checksum; | |
129 | info->cfg_checksum = cfg_checksum; | |
130 | if (function_name) | |
131 | info->function_name = kstrdup(function_name, GFP_KERNEL); | |
132 | ||
133 | list_add_tail(&info->head, ¤t_info->functions); | |
134 | } | |
135 | EXPORT_SYMBOL(llvm_gcda_emit_function); | |
136 | ||
137 | void llvm_gcda_emit_arcs(u32 num_counters, u64 *counters) | |
138 | { | |
139 | struct gcov_fn_info *info = list_last_entry(¤t_info->functions, | |
140 | struct gcov_fn_info, head); | |
141 | ||
142 | info->num_counters = num_counters; | |
143 | info->counters = counters; | |
144 | } | |
145 | EXPORT_SYMBOL(llvm_gcda_emit_arcs); | |
146 | ||
147 | void llvm_gcda_summary_info(void) | |
148 | { | |
149 | } | |
150 | EXPORT_SYMBOL(llvm_gcda_summary_info); | |
151 | ||
152 | void llvm_gcda_end_file(void) | |
153 | { | |
154 | } | |
155 | EXPORT_SYMBOL(llvm_gcda_end_file); | |
156 | ||
157 | /** | |
158 | * gcov_info_filename - return info filename | |
159 | * @info: profiling data set | |
160 | */ | |
161 | const char *gcov_info_filename(struct gcov_info *info) | |
162 | { | |
163 | return info->filename; | |
164 | } | |
165 | ||
166 | /** | |
167 | * gcov_info_version - return info version | |
168 | * @info: profiling data set | |
169 | */ | |
170 | unsigned int gcov_info_version(struct gcov_info *info) | |
171 | { | |
172 | return info->version; | |
173 | } | |
174 | ||
175 | /** | |
176 | * gcov_info_next - return next profiling data set | |
177 | * @info: profiling data set | |
178 | * | |
179 | * Returns next gcov_info following @info or first gcov_info in the chain if | |
180 | * @info is %NULL. | |
181 | */ | |
182 | struct gcov_info *gcov_info_next(struct gcov_info *info) | |
183 | { | |
184 | if (!info) | |
185 | return list_first_entry_or_null(&clang_gcov_list, | |
186 | struct gcov_info, head); | |
187 | if (list_is_last(&info->head, &clang_gcov_list)) | |
188 | return NULL; | |
189 | return list_next_entry(info, head); | |
190 | } | |
191 | ||
192 | /** | |
193 | * gcov_info_link - link/add profiling data set to the list | |
194 | * @info: profiling data set | |
195 | */ | |
196 | void gcov_info_link(struct gcov_info *info) | |
197 | { | |
198 | list_add_tail(&info->head, &clang_gcov_list); | |
199 | } | |
200 | ||
201 | /** | |
202 | * gcov_info_unlink - unlink/remove profiling data set from the list | |
203 | * @prev: previous profiling data set | |
204 | * @info: profiling data set | |
205 | */ | |
206 | void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info) | |
207 | { | |
208 | /* Generic code unlinks while iterating. */ | |
209 | __list_del_entry(&info->head); | |
210 | } | |
211 | ||
212 | /** | |
213 | * gcov_info_within_module - check if a profiling data set belongs to a module | |
214 | * @info: profiling data set | |
215 | * @mod: module | |
216 | * | |
217 | * Returns true if profiling data belongs module, false otherwise. | |
218 | */ | |
219 | bool gcov_info_within_module(struct gcov_info *info, struct module *mod) | |
220 | { | |
221 | return within_module((unsigned long)info->filename, mod); | |
222 | } | |
223 | ||
224 | /* Symbolic links to be created for each profiling data file. */ | |
225 | const struct gcov_link gcov_link[] = { | |
226 | { OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */ | |
227 | { 0, NULL}, | |
228 | }; | |
229 | ||
230 | /** | |
231 | * gcov_info_reset - reset profiling data to zero | |
232 | * @info: profiling data set | |
233 | */ | |
234 | void gcov_info_reset(struct gcov_info *info) | |
235 | { | |
236 | struct gcov_fn_info *fn; | |
237 | ||
238 | list_for_each_entry(fn, &info->functions, head) | |
239 | memset(fn->counters, 0, | |
240 | sizeof(fn->counters[0]) * fn->num_counters); | |
241 | } | |
242 | ||
243 | /** | |
244 | * gcov_info_is_compatible - check if profiling data can be added | |
245 | * @info1: first profiling data set | |
246 | * @info2: second profiling data set | |
247 | * | |
248 | * Returns non-zero if profiling data can be added, zero otherwise. | |
249 | */ | |
250 | int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2) | |
251 | { | |
252 | struct gcov_fn_info *fn_ptr1 = list_first_entry_or_null( | |
253 | &info1->functions, struct gcov_fn_info, head); | |
254 | struct gcov_fn_info *fn_ptr2 = list_first_entry_or_null( | |
255 | &info2->functions, struct gcov_fn_info, head); | |
256 | ||
257 | if (info1->checksum != info2->checksum) | |
258 | return false; | |
259 | if (!fn_ptr1) | |
260 | return fn_ptr1 == fn_ptr2; | |
261 | while (!list_is_last(&fn_ptr1->head, &info1->functions) && | |
262 | !list_is_last(&fn_ptr2->head, &info2->functions)) { | |
263 | if (fn_ptr1->checksum != fn_ptr2->checksum) | |
264 | return false; | |
265 | if (fn_ptr1->use_extra_checksum != fn_ptr2->use_extra_checksum) | |
266 | return false; | |
267 | if (fn_ptr1->use_extra_checksum && | |
268 | fn_ptr1->cfg_checksum != fn_ptr2->cfg_checksum) | |
269 | return false; | |
270 | fn_ptr1 = list_next_entry(fn_ptr1, head); | |
271 | fn_ptr2 = list_next_entry(fn_ptr2, head); | |
272 | } | |
273 | return list_is_last(&fn_ptr1->head, &info1->functions) && | |
274 | list_is_last(&fn_ptr2->head, &info2->functions); | |
275 | } | |
276 | ||
277 | /** | |
278 | * gcov_info_add - add up profiling data | |
279 | * @dest: profiling data set to which data is added | |
280 | * @source: profiling data set which is added | |
281 | * | |
282 | * Adds profiling counts of @source to @dest. | |
283 | */ | |
284 | void gcov_info_add(struct gcov_info *dst, struct gcov_info *src) | |
285 | { | |
286 | struct gcov_fn_info *dfn_ptr; | |
287 | struct gcov_fn_info *sfn_ptr = list_first_entry_or_null(&src->functions, | |
288 | struct gcov_fn_info, head); | |
289 | ||
290 | list_for_each_entry(dfn_ptr, &dst->functions, head) { | |
291 | u32 i; | |
292 | ||
293 | for (i = 0; i < sfn_ptr->num_counters; i++) | |
294 | dfn_ptr->counters[i] += sfn_ptr->counters[i]; | |
295 | } | |
296 | } | |
297 | ||
298 | static struct gcov_fn_info *gcov_fn_info_dup(struct gcov_fn_info *fn) | |
299 | { | |
300 | size_t cv_size; /* counter values size */ | |
301 | struct gcov_fn_info *fn_dup = kmemdup(fn, sizeof(*fn), | |
302 | GFP_KERNEL); | |
303 | if (!fn_dup) | |
304 | return NULL; | |
305 | INIT_LIST_HEAD(&fn_dup->head); | |
306 | ||
307 | fn_dup->function_name = kstrdup(fn->function_name, GFP_KERNEL); | |
308 | if (!fn_dup->function_name) | |
309 | goto err_name; | |
310 | ||
311 | cv_size = fn->num_counters * sizeof(fn->counters[0]); | |
312 | fn_dup->counters = vmalloc(cv_size); | |
313 | if (!fn_dup->counters) | |
314 | goto err_counters; | |
315 | memcpy(fn_dup->counters, fn->counters, cv_size); | |
316 | ||
317 | return fn_dup; | |
318 | ||
319 | err_counters: | |
320 | kfree(fn_dup->function_name); | |
321 | err_name: | |
322 | kfree(fn_dup); | |
323 | return NULL; | |
324 | } | |
325 | ||
326 | /** | |
327 | * gcov_info_dup - duplicate profiling data set | |
328 | * @info: profiling data set to duplicate | |
329 | * | |
330 | * Return newly allocated duplicate on success, %NULL on error. | |
331 | */ | |
332 | struct gcov_info *gcov_info_dup(struct gcov_info *info) | |
333 | { | |
334 | struct gcov_info *dup; | |
335 | struct gcov_fn_info *fn; | |
336 | ||
337 | dup = kmemdup(info, sizeof(*dup), GFP_KERNEL); | |
338 | if (!dup) | |
339 | return NULL; | |
340 | INIT_LIST_HEAD(&dup->head); | |
341 | INIT_LIST_HEAD(&dup->functions); | |
342 | dup->filename = kstrdup(info->filename, GFP_KERNEL); | |
343 | if (!dup->filename) | |
344 | goto err; | |
345 | ||
346 | list_for_each_entry(fn, &info->functions, head) { | |
347 | struct gcov_fn_info *fn_dup = gcov_fn_info_dup(fn); | |
348 | ||
349 | if (!fn_dup) | |
350 | goto err; | |
351 | list_add_tail(&fn_dup->head, &dup->functions); | |
352 | } | |
353 | ||
354 | return dup; | |
355 | ||
356 | err: | |
357 | gcov_info_free(dup); | |
358 | return NULL; | |
359 | } | |
360 | ||
361 | /** | |
362 | * gcov_info_free - release memory for profiling data set duplicate | |
363 | * @info: profiling data set duplicate to free | |
364 | */ | |
365 | void gcov_info_free(struct gcov_info *info) | |
366 | { | |
367 | struct gcov_fn_info *fn, *tmp; | |
368 | ||
369 | list_for_each_entry_safe(fn, tmp, &info->functions, head) { | |
370 | kfree(fn->function_name); | |
371 | vfree(fn->counters); | |
372 | list_del(&fn->head); | |
373 | kfree(fn); | |
374 | } | |
375 | kfree(info->filename); | |
376 | kfree(info); | |
377 | } | |
378 | ||
379 | #define ITER_STRIDE PAGE_SIZE | |
380 | ||
381 | /** | |
382 | * struct gcov_iterator - specifies current file position in logical records | |
383 | * @info: associated profiling data | |
384 | * @buffer: buffer containing file data | |
385 | * @size: size of buffer | |
386 | * @pos: current position in file | |
387 | */ | |
388 | struct gcov_iterator { | |
389 | struct gcov_info *info; | |
390 | void *buffer; | |
391 | size_t size; | |
392 | loff_t pos; | |
393 | }; | |
394 | ||
395 | /** | |
396 | * store_gcov_u32 - store 32 bit number in gcov format to buffer | |
397 | * @buffer: target buffer or NULL | |
398 | * @off: offset into the buffer | |
399 | * @v: value to be stored | |
400 | * | |
401 | * Number format defined by gcc: numbers are recorded in the 32 bit | |
402 | * unsigned binary form of the endianness of the machine generating the | |
403 | * file. Returns the number of bytes stored. If @buffer is %NULL, doesn't | |
404 | * store anything. | |
405 | */ | |
406 | static size_t store_gcov_u32(void *buffer, size_t off, u32 v) | |
407 | { | |
408 | u32 *data; | |
409 | ||
410 | if (buffer) { | |
411 | data = buffer + off; | |
412 | *data = v; | |
413 | } | |
414 | ||
415 | return sizeof(*data); | |
416 | } | |
417 | ||
418 | /** | |
419 | * store_gcov_u64 - store 64 bit number in gcov format to buffer | |
420 | * @buffer: target buffer or NULL | |
421 | * @off: offset into the buffer | |
422 | * @v: value to be stored | |
423 | * | |
424 | * Number format defined by gcc: numbers are recorded in the 32 bit | |
425 | * unsigned binary form of the endianness of the machine generating the | |
426 | * file. 64 bit numbers are stored as two 32 bit numbers, the low part | |
427 | * first. Returns the number of bytes stored. If @buffer is %NULL, doesn't store | |
428 | * anything. | |
429 | */ | |
430 | static size_t store_gcov_u64(void *buffer, size_t off, u64 v) | |
431 | { | |
432 | u32 *data; | |
433 | ||
434 | if (buffer) { | |
435 | data = buffer + off; | |
436 | ||
437 | data[0] = (v & 0xffffffffUL); | |
438 | data[1] = (v >> 32); | |
439 | } | |
440 | ||
441 | return sizeof(*data) * 2; | |
442 | } | |
443 | ||
444 | /** | |
445 | * convert_to_gcda - convert profiling data set to gcda file format | |
446 | * @buffer: the buffer to store file data or %NULL if no data should be stored | |
447 | * @info: profiling data set to be converted | |
448 | * | |
449 | * Returns the number of bytes that were/would have been stored into the buffer. | |
450 | */ | |
451 | static size_t convert_to_gcda(char *buffer, struct gcov_info *info) | |
452 | { | |
453 | struct gcov_fn_info *fi_ptr; | |
454 | size_t pos = 0; | |
455 | ||
456 | /* File header. */ | |
457 | pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC); | |
458 | pos += store_gcov_u32(buffer, pos, info->version); | |
459 | pos += store_gcov_u32(buffer, pos, info->checksum); | |
460 | ||
461 | list_for_each_entry(fi_ptr, &info->functions, head) { | |
462 | u32 i; | |
463 | u32 len = 2; | |
464 | ||
465 | if (fi_ptr->use_extra_checksum) | |
466 | len++; | |
467 | ||
468 | pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION); | |
469 | pos += store_gcov_u32(buffer, pos, len); | |
470 | pos += store_gcov_u32(buffer, pos, fi_ptr->ident); | |
471 | pos += store_gcov_u32(buffer, pos, fi_ptr->checksum); | |
472 | if (fi_ptr->use_extra_checksum) | |
473 | pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum); | |
474 | ||
475 | pos += store_gcov_u32(buffer, pos, GCOV_TAG_COUNTER_BASE); | |
476 | pos += store_gcov_u32(buffer, pos, fi_ptr->num_counters * 2); | |
477 | for (i = 0; i < fi_ptr->num_counters; i++) | |
478 | pos += store_gcov_u64(buffer, pos, fi_ptr->counters[i]); | |
479 | } | |
480 | ||
481 | return pos; | |
482 | } | |
483 | ||
484 | /** | |
485 | * gcov_iter_new - allocate and initialize profiling data iterator | |
486 | * @info: profiling data set to be iterated | |
487 | * | |
488 | * Return file iterator on success, %NULL otherwise. | |
489 | */ | |
490 | struct gcov_iterator *gcov_iter_new(struct gcov_info *info) | |
491 | { | |
492 | struct gcov_iterator *iter; | |
493 | ||
494 | iter = kzalloc(sizeof(struct gcov_iterator), GFP_KERNEL); | |
495 | if (!iter) | |
496 | goto err_free; | |
497 | ||
498 | iter->info = info; | |
499 | /* Dry-run to get the actual buffer size. */ | |
500 | iter->size = convert_to_gcda(NULL, info); | |
501 | iter->buffer = vmalloc(iter->size); | |
502 | if (!iter->buffer) | |
503 | goto err_free; | |
504 | ||
505 | convert_to_gcda(iter->buffer, info); | |
506 | ||
507 | return iter; | |
508 | ||
509 | err_free: | |
510 | kfree(iter); | |
511 | return NULL; | |
512 | } | |
513 | ||
514 | ||
515 | /** | |
516 | * gcov_iter_get_info - return profiling data set for given file iterator | |
517 | * @iter: file iterator | |
518 | */ | |
519 | void gcov_iter_free(struct gcov_iterator *iter) | |
520 | { | |
521 | vfree(iter->buffer); | |
522 | kfree(iter); | |
523 | } | |
524 | ||
525 | /** | |
526 | * gcov_iter_get_info - return profiling data set for given file iterator | |
527 | * @iter: file iterator | |
528 | */ | |
529 | struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter) | |
530 | { | |
531 | return iter->info; | |
532 | } | |
533 | ||
534 | /** | |
535 | * gcov_iter_start - reset file iterator to starting position | |
536 | * @iter: file iterator | |
537 | */ | |
538 | void gcov_iter_start(struct gcov_iterator *iter) | |
539 | { | |
540 | iter->pos = 0; | |
541 | } | |
542 | ||
543 | /** | |
544 | * gcov_iter_next - advance file iterator to next logical record | |
545 | * @iter: file iterator | |
546 | * | |
547 | * Return zero if new position is valid, non-zero if iterator has reached end. | |
548 | */ | |
549 | int gcov_iter_next(struct gcov_iterator *iter) | |
550 | { | |
551 | if (iter->pos < iter->size) | |
552 | iter->pos += ITER_STRIDE; | |
553 | ||
554 | if (iter->pos >= iter->size) | |
555 | return -EINVAL; | |
556 | ||
557 | return 0; | |
558 | } | |
559 | ||
560 | /** | |
561 | * gcov_iter_write - write data for current pos to seq_file | |
562 | * @iter: file iterator | |
563 | * @seq: seq_file handle | |
564 | * | |
565 | * Return zero on success, non-zero otherwise. | |
566 | */ | |
567 | int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq) | |
568 | { | |
569 | size_t len; | |
570 | ||
571 | if (iter->pos >= iter->size) | |
572 | return -EINVAL; | |
573 | ||
574 | len = ITER_STRIDE; | |
575 | if (iter->pos + len > iter->size) | |
576 | len = iter->size - iter->pos; | |
577 | ||
578 | seq_write(seq, iter->buffer + iter->pos, len); | |
579 | ||
580 | return 0; | |
581 | } |