Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * This code provides functions to handle gcc's profiling data format
4 : * introduced with gcc 4.7.
5 : *
6 : * This file is based heavily on gcc_3_4.c file.
7 : *
8 : * For a better understanding, refer to gcc source:
9 : * gcc/gcov-io.h
10 : * libgcc/libgcov.c
11 : *
12 : * Uses gcc-internal data definitions.
13 : */
14 :
15 : #include <linux/errno.h>
16 : #include <linux/slab.h>
17 : #include <linux/string.h>
18 : #include <linux/seq_file.h>
19 : #include <linux/vmalloc.h>
20 : #include "gcov.h"
21 :
22 : #if (__GNUC__ >= 10)
23 : #define GCOV_COUNTERS 8
24 : #elif (__GNUC__ >= 7)
25 : #define GCOV_COUNTERS 9
26 : #elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)
27 : #define GCOV_COUNTERS 10
28 : #else
29 : #define GCOV_COUNTERS 9
30 : #endif
31 :
32 : #define GCOV_TAG_FUNCTION_LENGTH 3
33 :
34 : static struct gcov_info *gcov_info_head;
35 :
36 : /**
37 : * struct gcov_ctr_info - information about counters for a single function
38 : * @num: number of counter values for this type
39 : * @values: array of counter values for this type
40 : *
41 : * This data is generated by gcc during compilation and doesn't change
42 : * at run-time with the exception of the values array.
43 : */
44 : struct gcov_ctr_info {
45 : unsigned int num;
46 : gcov_type *values;
47 : };
48 :
49 : /**
50 : * struct gcov_fn_info - profiling meta data per function
51 : * @key: comdat key
52 : * @ident: unique ident of function
53 : * @lineno_checksum: function lineo_checksum
54 : * @cfg_checksum: function cfg checksum
55 : * @ctrs: instrumented counters
56 : *
57 : * This data is generated by gcc during compilation and doesn't change
58 : * at run-time.
59 : *
60 : * Information about a single function. This uses the trailing array
61 : * idiom. The number of counters is determined from the merge pointer
62 : * array in gcov_info. The key is used to detect which of a set of
63 : * comdat functions was selected -- it points to the gcov_info object
64 : * of the object file containing the selected comdat function.
65 : */
66 : struct gcov_fn_info {
67 : const struct gcov_info *key;
68 : unsigned int ident;
69 : unsigned int lineno_checksum;
70 : unsigned int cfg_checksum;
71 : struct gcov_ctr_info ctrs[];
72 : };
73 :
74 : /**
75 : * struct gcov_info - profiling data per object file
76 : * @version: gcov version magic indicating the gcc version used for compilation
77 : * @next: list head for a singly-linked list
78 : * @stamp: uniquifying time stamp
79 : * @filename: name of the associated gcov data file
80 : * @merge: merge functions (null for unused counter type)
81 : * @n_functions: number of instrumented functions
82 : * @functions: pointer to pointers to function information
83 : *
84 : * This data is generated by gcc during compilation and doesn't change
85 : * at run-time with the exception of the next pointer.
86 : */
87 : struct gcov_info {
88 : unsigned int version;
89 : struct gcov_info *next;
90 : unsigned int stamp;
91 : const char *filename;
92 : void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int);
93 : unsigned int n_functions;
94 : struct gcov_fn_info **functions;
95 : };
96 :
97 : /**
98 : * gcov_info_filename - return info filename
99 : * @info: profiling data set
100 : */
101 458400 : const char *gcov_info_filename(struct gcov_info *info)
102 : {
103 458400 : return info->filename;
104 : }
105 :
106 : /**
107 : * gcov_info_version - return info version
108 : * @info: profiling data set
109 : */
110 1 : unsigned int gcov_info_version(struct gcov_info *info)
111 : {
112 1 : return info->version;
113 : }
114 :
115 : /**
116 : * gcov_info_next - return next profiling data set
117 : * @info: profiling data set
118 : *
119 : * Returns next gcov_info following @info or first gcov_info in the chain if
120 : * @info is %NULL.
121 : */
122 956 : struct gcov_info *gcov_info_next(struct gcov_info *info)
123 : {
124 956 : if (!info)
125 1 : return gcov_info_head;
126 :
127 955 : return info->next;
128 : }
129 :
130 : /**
131 : * gcov_info_link - link/add profiling data set to the list
132 : * @info: profiling data set
133 : */
134 955 : void gcov_info_link(struct gcov_info *info)
135 : {
136 955 : info->next = gcov_info_head;
137 955 : gcov_info_head = info;
138 955 : }
139 :
140 : /**
141 : * gcov_info_unlink - unlink/remove profiling data set from the list
142 : * @prev: previous profiling data set
143 : * @info: profiling data set
144 : */
145 0 : void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
146 : {
147 0 : if (prev)
148 0 : prev->next = info->next;
149 : else
150 0 : gcov_info_head = info->next;
151 0 : }
152 :
153 : /**
154 : * gcov_info_within_module - check if a profiling data set belongs to a module
155 : * @info: profiling data set
156 : * @mod: module
157 : *
158 : * Returns true if profiling data belongs module, false otherwise.
159 : */
160 0 : bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
161 : {
162 0 : return within_module((unsigned long)info, mod);
163 : }
164 :
165 : /* Symbolic links to be created for each profiling data file. */
166 : const struct gcov_link gcov_link[] = {
167 : { OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
168 : { 0, NULL},
169 : };
170 :
171 : /*
172 : * Determine whether a counter is active. Doesn't change at run-time.
173 : */
174 102184 : static int counter_active(struct gcov_info *info, unsigned int type)
175 : {
176 102184 : return info->merge[type] ? 1 : 0;
177 : }
178 :
179 : /* Determine number of active counters. Based on gcc magic. */
180 : static unsigned int num_counter_active(struct gcov_info *info)
181 : {
182 : unsigned int i;
183 : unsigned int result = 0;
184 :
185 2184 : for (i = 0; i < GCOV_COUNTERS; i++) {
186 2184 : if (counter_active(info, i))
187 273 : result++;
188 : }
189 137 : return result;
190 : }
191 :
192 : /**
193 : * gcov_info_reset - reset profiling data to zero
194 : * @info: profiling data set
195 : */
196 0 : void gcov_info_reset(struct gcov_info *info)
197 : {
198 0 : struct gcov_ctr_info *ci_ptr;
199 0 : unsigned int fi_idx;
200 0 : unsigned int ct_idx;
201 :
202 0 : for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
203 0 : ci_ptr = info->functions[fi_idx]->ctrs;
204 :
205 0 : for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
206 0 : if (!counter_active(info, ct_idx))
207 0 : continue;
208 :
209 0 : memset(ci_ptr->values, 0,
210 0 : sizeof(gcov_type) * ci_ptr->num);
211 0 : ci_ptr++;
212 : }
213 : }
214 0 : }
215 :
216 : /**
217 : * gcov_info_is_compatible - check if profiling data can be added
218 : * @info1: first profiling data set
219 : * @info2: second profiling data set
220 : *
221 : * Returns non-zero if profiling data can be added, zero otherwise.
222 : */
223 0 : int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
224 : {
225 0 : return (info1->stamp == info2->stamp);
226 : }
227 :
228 : /**
229 : * gcov_info_add - add up profiling data
230 : * @dst: profiling data set to which data is added
231 : * @src: profiling data set which is added
232 : *
233 : * Adds profiling counts of @src to @dst.
234 : */
235 0 : void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
236 : {
237 0 : struct gcov_ctr_info *dci_ptr;
238 0 : struct gcov_ctr_info *sci_ptr;
239 0 : unsigned int fi_idx;
240 0 : unsigned int ct_idx;
241 0 : unsigned int val_idx;
242 :
243 0 : for (fi_idx = 0; fi_idx < src->n_functions; fi_idx++) {
244 0 : dci_ptr = dst->functions[fi_idx]->ctrs;
245 0 : sci_ptr = src->functions[fi_idx]->ctrs;
246 :
247 0 : for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
248 0 : if (!counter_active(src, ct_idx))
249 0 : continue;
250 :
251 0 : for (val_idx = 0; val_idx < sci_ptr->num; val_idx++)
252 0 : dci_ptr->values[val_idx] +=
253 0 : sci_ptr->values[val_idx];
254 :
255 0 : dci_ptr++;
256 0 : sci_ptr++;
257 : }
258 : }
259 0 : }
260 :
261 : /**
262 : * gcov_info_dup - duplicate profiling data set
263 : * @info: profiling data set to duplicate
264 : *
265 : * Return newly allocated duplicate on success, %NULL on error.
266 : */
267 137 : struct gcov_info *gcov_info_dup(struct gcov_info *info)
268 : {
269 137 : struct gcov_info *dup;
270 137 : struct gcov_ctr_info *dci_ptr; /* dst counter info */
271 137 : struct gcov_ctr_info *sci_ptr; /* src counter info */
272 137 : unsigned int active;
273 137 : unsigned int fi_idx; /* function info idx */
274 137 : unsigned int ct_idx; /* counter type idx */
275 137 : size_t fi_size; /* function info size */
276 137 : size_t cv_size; /* counter values size */
277 :
278 137 : dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
279 137 : if (!dup)
280 : return NULL;
281 :
282 137 : dup->next = NULL;
283 137 : dup->filename = NULL;
284 137 : dup->functions = NULL;
285 :
286 137 : dup->filename = kstrdup(info->filename, GFP_KERNEL);
287 137 : if (!dup->filename)
288 0 : goto err_free;
289 :
290 137 : dup->functions = kcalloc(info->n_functions,
291 : sizeof(struct gcov_fn_info *), GFP_KERNEL);
292 137 : if (!dup->functions)
293 0 : goto err_free;
294 :
295 1233 : active = num_counter_active(info);
296 137 : fi_size = sizeof(struct gcov_fn_info);
297 137 : fi_size += sizeof(struct gcov_ctr_info) * active;
298 :
299 6395 : for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
300 6259 : dup->functions[fi_idx] = kzalloc(fi_size, GFP_KERNEL);
301 6259 : if (!dup->functions[fi_idx])
302 0 : goto err_free;
303 :
304 6259 : *(dup->functions[fi_idx]) = *(info->functions[fi_idx]);
305 :
306 6259 : sci_ptr = info->functions[fi_idx]->ctrs;
307 6259 : dci_ptr = dup->functions[fi_idx]->ctrs;
308 :
309 12517 : for (ct_idx = 0; ct_idx < active; ct_idx++) {
310 :
311 6259 : cv_size = sizeof(gcov_type) * sci_ptr->num;
312 :
313 6259 : dci_ptr->values = vmalloc(cv_size);
314 :
315 6258 : if (!dci_ptr->values)
316 0 : goto err_free;
317 :
318 6258 : dci_ptr->num = sci_ptr->num;
319 6258 : memcpy(dci_ptr->values, sci_ptr->values, cv_size);
320 :
321 6258 : sci_ptr++;
322 6258 : dci_ptr++;
323 : }
324 : }
325 :
326 : return dup;
327 0 : err_free:
328 0 : gcov_info_free(dup);
329 0 : return NULL;
330 : }
331 :
332 : /**
333 : * gcov_info_free - release memory for profiling data set duplicate
334 : * @info: profiling data set duplicate to free
335 : */
336 136 : void gcov_info_free(struct gcov_info *info)
337 : {
338 136 : unsigned int active;
339 136 : unsigned int fi_idx;
340 136 : unsigned int ct_idx;
341 136 : struct gcov_ctr_info *ci_ptr;
342 :
343 136 : if (!info->functions)
344 0 : goto free_info;
345 :
346 1224 : active = num_counter_active(info);
347 :
348 6386 : for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
349 6250 : if (!info->functions[fi_idx])
350 0 : continue;
351 :
352 6250 : ci_ptr = info->functions[fi_idx]->ctrs;
353 :
354 12500 : for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++)
355 6250 : vfree(ci_ptr->values);
356 :
357 6250 : kfree(info->functions[fi_idx]);
358 : }
359 :
360 136 : free_info:
361 136 : kfree(info->functions);
362 136 : kfree(info->filename);
363 136 : kfree(info);
364 136 : }
365 :
366 : #define ITER_STRIDE PAGE_SIZE
367 :
368 : /**
369 : * struct gcov_iterator - specifies current file position in logical records
370 : * @info: associated profiling data
371 : * @buffer: buffer containing file data
372 : * @size: size of buffer
373 : * @pos: current position in file
374 : */
375 : struct gcov_iterator {
376 : struct gcov_info *info;
377 : void *buffer;
378 : size_t size;
379 : loff_t pos;
380 : };
381 :
382 : /**
383 : * store_gcov_u32 - store 32 bit number in gcov format to buffer
384 : * @buffer: target buffer or NULL
385 : * @off: offset into the buffer
386 : * @v: value to be stored
387 : *
388 : * Number format defined by gcc: numbers are recorded in the 32 bit
389 : * unsigned binary form of the endianness of the machine generating the
390 : * file. Returns the number of bytes stored. If @buffer is %NULL, doesn't
391 : * store anything.
392 : */
393 88316 : static size_t store_gcov_u32(void *buffer, size_t off, u32 v)
394 : {
395 88316 : u32 *data;
396 :
397 88316 : if (buffer) {
398 44158 : data = buffer + off;
399 44158 : *data = v;
400 : }
401 :
402 88044 : return sizeof(*data);
403 : }
404 :
405 : /**
406 : * store_gcov_u64 - store 64 bit number in gcov format to buffer
407 : * @buffer: target buffer or NULL
408 : * @off: offset into the buffer
409 : * @v: value to be stored
410 : *
411 : * Number format defined by gcc: numbers are recorded in the 32 bit
412 : * unsigned binary form of the endianness of the machine generating the
413 : * file. 64 bit numbers are stored as two 32 bit numbers, the low part
414 : * first. Returns the number of bytes stored. If @buffer is %NULL, doesn't store
415 : * anything.
416 : */
417 99228 : static size_t store_gcov_u64(void *buffer, size_t off, u64 v)
418 : {
419 99228 : u32 *data;
420 :
421 99228 : if (buffer) {
422 49614 : data = buffer + off;
423 :
424 49614 : data[0] = (v & 0xffffffffUL);
425 49614 : data[1] = (v >> 32);
426 : }
427 :
428 99228 : return sizeof(*data) * 2;
429 : }
430 :
431 : /**
432 : * convert_to_gcda - convert profiling data set to gcda file format
433 : * @buffer: the buffer to store file data or %NULL if no data should be stored
434 : * @info: profiling data set to be converted
435 : *
436 : * Returns the number of bytes that were/would have been stored into the buffer.
437 : */
438 272 : static size_t convert_to_gcda(char *buffer, struct gcov_info *info)
439 : {
440 272 : struct gcov_fn_info *fi_ptr;
441 272 : struct gcov_ctr_info *ci_ptr;
442 272 : unsigned int fi_idx;
443 272 : unsigned int ct_idx;
444 272 : unsigned int cv_idx;
445 272 : size_t pos = 0;
446 :
447 : /* File header. */
448 272 : pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
449 272 : pos += store_gcov_u32(buffer, pos, info->version);
450 272 : pos += store_gcov_u32(buffer, pos, info->stamp);
451 :
452 12772 : for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
453 12500 : fi_ptr = info->functions[fi_idx];
454 :
455 : /* Function record. */
456 12500 : pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
457 12500 : pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION_LENGTH);
458 12500 : pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
459 12500 : pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum);
460 12500 : pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
461 :
462 12500 : ci_ptr = fi_ptr->ctrs;
463 :
464 112500 : for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
465 100000 : if (!counter_active(info, ct_idx))
466 87500 : continue;
467 :
468 : /* Counter record. */
469 25000 : pos += store_gcov_u32(buffer, pos,
470 12500 : GCOV_TAG_FOR_COUNTER(ct_idx));
471 12500 : pos += store_gcov_u32(buffer, pos, ci_ptr->num * 2);
472 :
473 111728 : for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
474 99228 : pos += store_gcov_u64(buffer, pos,
475 99228 : ci_ptr->values[cv_idx]);
476 : }
477 :
478 12500 : ci_ptr++;
479 : }
480 : }
481 :
482 272 : return pos;
483 : }
484 :
485 : /**
486 : * gcov_iter_new - allocate and initialize profiling data iterator
487 : * @info: profiling data set to be iterated
488 : *
489 : * Return file iterator on success, %NULL otherwise.
490 : */
491 136 : struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
492 : {
493 136 : struct gcov_iterator *iter;
494 :
495 136 : iter = kzalloc(sizeof(struct gcov_iterator), GFP_KERNEL);
496 136 : if (!iter)
497 0 : goto err_free;
498 :
499 136 : iter->info = info;
500 : /* Dry-run to get the actual buffer size. */
501 136 : iter->size = convert_to_gcda(NULL, info);
502 136 : iter->buffer = vmalloc(iter->size);
503 136 : if (!iter->buffer)
504 0 : goto err_free;
505 :
506 136 : convert_to_gcda(iter->buffer, info);
507 :
508 136 : return iter;
509 :
510 0 : err_free:
511 0 : kfree(iter);
512 0 : return NULL;
513 : }
514 :
515 :
516 : /**
517 : * gcov_iter_get_info - return profiling data set for given file iterator
518 : * @iter: file iterator
519 : */
520 136 : void gcov_iter_free(struct gcov_iterator *iter)
521 : {
522 136 : vfree(iter->buffer);
523 136 : kfree(iter);
524 136 : }
525 :
526 : /**
527 : * gcov_iter_get_info - return profiling data set for given file iterator
528 : * @iter: file iterator
529 : */
530 136 : struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter)
531 : {
532 136 : return iter->info;
533 : }
534 :
535 : /**
536 : * gcov_iter_start - reset file iterator to starting position
537 : * @iter: file iterator
538 : */
539 360 : void gcov_iter_start(struct gcov_iterator *iter)
540 : {
541 360 : iter->pos = 0;
542 360 : }
543 :
544 : /**
545 : * gcov_iter_next - advance file iterator to next logical record
546 : * @iter: file iterator
547 : *
548 : * Return zero if new position is valid, non-zero if iterator has reached end.
549 : */
550 565 : int gcov_iter_next(struct gcov_iterator *iter)
551 : {
552 565 : if (iter->pos < iter->size)
553 565 : iter->pos += ITER_STRIDE;
554 :
555 565 : if (iter->pos >= iter->size)
556 272 : return -EINVAL;
557 :
558 : return 0;
559 : }
560 :
561 : /**
562 : * gcov_iter_write - write data for current pos to seq_file
563 : * @iter: file iterator
564 : * @seq: seq_file handle
565 : *
566 : * Return zero on success, non-zero otherwise.
567 : */
568 312 : int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq)
569 : {
570 312 : size_t len;
571 :
572 312 : if (iter->pos >= iter->size)
573 : return -EINVAL;
574 :
575 312 : len = ITER_STRIDE;
576 312 : if (iter->pos + len > iter->size)
577 136 : len = iter->size - iter->pos;
578 :
579 312 : seq_write(seq, iter->buffer + iter->pos, len);
580 :
581 312 : return 0;
582 : }
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