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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__ >= 7)
23#define GCOV_COUNTERS 9
24#elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)
25#define GCOV_COUNTERS 10
26#elif __GNUC__ == 4 && __GNUC_MINOR__ >= 9
27#define GCOV_COUNTERS 9
28#else
29#define GCOV_COUNTERS 8
30#endif
31
32#define GCOV_TAG_FUNCTION_LENGTH 3
33
34static 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 */
44struct 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 */
66struct 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[0];
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 */
87struct 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 */
101const char *gcov_info_filename(struct gcov_info *info)
102{
103 return info->filename;
104}
105
106/**
107 * gcov_info_version - return info version
108 * @info: profiling data set
109 */
110unsigned int gcov_info_version(struct gcov_info *info)
111{
112 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 */
122struct gcov_info *gcov_info_next(struct gcov_info *info)
123{
124 if (!info)
125 return gcov_info_head;
126
127 return info->next;
128}
129
130/**
131 * gcov_info_link - link/add profiling data set to the list
132 * @info: profiling data set
133 */
134void gcov_info_link(struct gcov_info *info)
135{
136 info->next = gcov_info_head;
137 gcov_info_head = info;
138}
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 */
145void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
146{
147 if (prev)
148 prev->next = info->next;
149 else
150 gcov_info_head = info->next;
151}
152
153/* Symbolic links to be created for each profiling data file. */
154const struct gcov_link gcov_link[] = {
155 { OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
156 { 0, NULL},
157};
158
159/*
160 * Determine whether a counter is active. Doesn't change at run-time.
161 */
162static int counter_active(struct gcov_info *info, unsigned int type)
163{
164 return info->merge[type] ? 1 : 0;
165}
166
167/* Determine number of active counters. Based on gcc magic. */
168static unsigned int num_counter_active(struct gcov_info *info)
169{
170 unsigned int i;
171 unsigned int result = 0;
172
173 for (i = 0; i < GCOV_COUNTERS; i++) {
174 if (counter_active(info, i))
175 result++;
176 }
177 return result;
178}
179
180/**
181 * gcov_info_reset - reset profiling data to zero
182 * @info: profiling data set
183 */
184void gcov_info_reset(struct gcov_info *info)
185{
186 struct gcov_ctr_info *ci_ptr;
187 unsigned int fi_idx;
188 unsigned int ct_idx;
189
190 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
191 ci_ptr = info->functions[fi_idx]->ctrs;
192
193 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
194 if (!counter_active(info, ct_idx))
195 continue;
196
197 memset(ci_ptr->values, 0,
198 sizeof(gcov_type) * ci_ptr->num);
199 ci_ptr++;
200 }
201 }
202}
203
204/**
205 * gcov_info_is_compatible - check if profiling data can be added
206 * @info1: first profiling data set
207 * @info2: second profiling data set
208 *
209 * Returns non-zero if profiling data can be added, zero otherwise.
210 */
211int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
212{
213 return (info1->stamp == info2->stamp);
214}
215
216/**
217 * gcov_info_add - add up profiling data
218 * @dest: profiling data set to which data is added
219 * @source: profiling data set which is added
220 *
221 * Adds profiling counts of @source to @dest.
222 */
223void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
224{
225 struct gcov_ctr_info *dci_ptr;
226 struct gcov_ctr_info *sci_ptr;
227 unsigned int fi_idx;
228 unsigned int ct_idx;
229 unsigned int val_idx;
230
231 for (fi_idx = 0; fi_idx < src->n_functions; fi_idx++) {
232 dci_ptr = dst->functions[fi_idx]->ctrs;
233 sci_ptr = src->functions[fi_idx]->ctrs;
234
235 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
236 if (!counter_active(src, ct_idx))
237 continue;
238
239 for (val_idx = 0; val_idx < sci_ptr->num; val_idx++)
240 dci_ptr->values[val_idx] +=
241 sci_ptr->values[val_idx];
242
243 dci_ptr++;
244 sci_ptr++;
245 }
246 }
247}
248
249/**
250 * gcov_info_dup - duplicate profiling data set
251 * @info: profiling data set to duplicate
252 *
253 * Return newly allocated duplicate on success, %NULL on error.
254 */
255struct gcov_info *gcov_info_dup(struct gcov_info *info)
256{
257 struct gcov_info *dup;
258 struct gcov_ctr_info *dci_ptr; /* dst counter info */
259 struct gcov_ctr_info *sci_ptr; /* src counter info */
260 unsigned int active;
261 unsigned int fi_idx; /* function info idx */
262 unsigned int ct_idx; /* counter type idx */
263 size_t fi_size; /* function info size */
264 size_t cv_size; /* counter values size */
265
266 dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
267 if (!dup)
268 return NULL;
269
270 dup->next = NULL;
271 dup->filename = NULL;
272 dup->functions = NULL;
273
274 dup->filename = kstrdup(info->filename, GFP_KERNEL);
275 if (!dup->filename)
276 goto err_free;
277
278 dup->functions = kcalloc(info->n_functions,
279 sizeof(struct gcov_fn_info *), GFP_KERNEL);
280 if (!dup->functions)
281 goto err_free;
282
283 active = num_counter_active(info);
284 fi_size = sizeof(struct gcov_fn_info);
285 fi_size += sizeof(struct gcov_ctr_info) * active;
286
287 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
288 dup->functions[fi_idx] = kzalloc(fi_size, GFP_KERNEL);
289 if (!dup->functions[fi_idx])
290 goto err_free;
291
292 *(dup->functions[fi_idx]) = *(info->functions[fi_idx]);
293
294 sci_ptr = info->functions[fi_idx]->ctrs;
295 dci_ptr = dup->functions[fi_idx]->ctrs;
296
297 for (ct_idx = 0; ct_idx < active; ct_idx++) {
298
299 cv_size = sizeof(gcov_type) * sci_ptr->num;
300
301 dci_ptr->values = vmalloc(cv_size);
302
303 if (!dci_ptr->values)
304 goto err_free;
305
306 dci_ptr->num = sci_ptr->num;
307 memcpy(dci_ptr->values, sci_ptr->values, cv_size);
308
309 sci_ptr++;
310 dci_ptr++;
311 }
312 }
313
314 return dup;
315err_free:
316 gcov_info_free(dup);
317 return NULL;
318}
319
320/**
321 * gcov_info_free - release memory for profiling data set duplicate
322 * @info: profiling data set duplicate to free
323 */
324void gcov_info_free(struct gcov_info *info)
325{
326 unsigned int active;
327 unsigned int fi_idx;
328 unsigned int ct_idx;
329 struct gcov_ctr_info *ci_ptr;
330
331 if (!info->functions)
332 goto free_info;
333
334 active = num_counter_active(info);
335
336 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
337 if (!info->functions[fi_idx])
338 continue;
339
340 ci_ptr = info->functions[fi_idx]->ctrs;
341
342 for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++)
343 vfree(ci_ptr->values);
344
345 kfree(info->functions[fi_idx]);
346 }
347
348free_info:
349 kfree(info->functions);
350 kfree(info->filename);
351 kfree(info);
352}
353
354#define ITER_STRIDE PAGE_SIZE
355
356/**
357 * struct gcov_iterator - specifies current file position in logical records
358 * @info: associated profiling data
359 * @buffer: buffer containing file data
360 * @size: size of buffer
361 * @pos: current position in file
362 */
363struct gcov_iterator {
364 struct gcov_info *info;
365 void *buffer;
366 size_t size;
367 loff_t pos;
368};
369
370/**
371 * store_gcov_u32 - store 32 bit number in gcov format to buffer
372 * @buffer: target buffer or NULL
373 * @off: offset into the buffer
374 * @v: value to be stored
375 *
376 * Number format defined by gcc: numbers are recorded in the 32 bit
377 * unsigned binary form of the endianness of the machine generating the
378 * file. Returns the number of bytes stored. If @buffer is %NULL, doesn't
379 * store anything.
380 */
381static size_t store_gcov_u32(void *buffer, size_t off, u32 v)
382{
383 u32 *data;
384
385 if (buffer) {
386 data = buffer + off;
387 *data = v;
388 }
389
390 return sizeof(*data);
391}
392
393/**
394 * store_gcov_u64 - store 64 bit number in gcov format to buffer
395 * @buffer: target buffer or NULL
396 * @off: offset into the buffer
397 * @v: value to be stored
398 *
399 * Number format defined by gcc: numbers are recorded in the 32 bit
400 * unsigned binary form of the endianness of the machine generating the
401 * file. 64 bit numbers are stored as two 32 bit numbers, the low part
402 * first. Returns the number of bytes stored. If @buffer is %NULL, doesn't store
403 * anything.
404 */
405static size_t store_gcov_u64(void *buffer, size_t off, u64 v)
406{
407 u32 *data;
408
409 if (buffer) {
410 data = buffer + off;
411
412 data[0] = (v & 0xffffffffUL);
413 data[1] = (v >> 32);
414 }
415
416 return sizeof(*data) * 2;
417}
418
419/**
420 * convert_to_gcda - convert profiling data set to gcda file format
421 * @buffer: the buffer to store file data or %NULL if no data should be stored
422 * @info: profiling data set to be converted
423 *
424 * Returns the number of bytes that were/would have been stored into the buffer.
425 */
426static size_t convert_to_gcda(char *buffer, struct gcov_info *info)
427{
428 struct gcov_fn_info *fi_ptr;
429 struct gcov_ctr_info *ci_ptr;
430 unsigned int fi_idx;
431 unsigned int ct_idx;
432 unsigned int cv_idx;
433 size_t pos = 0;
434
435 /* File header. */
436 pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
437 pos += store_gcov_u32(buffer, pos, info->version);
438 pos += store_gcov_u32(buffer, pos, info->stamp);
439
440 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
441 fi_ptr = info->functions[fi_idx];
442
443 /* Function record. */
444 pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
445 pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION_LENGTH);
446 pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
447 pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum);
448 pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
449
450 ci_ptr = fi_ptr->ctrs;
451
452 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
453 if (!counter_active(info, ct_idx))
454 continue;
455
456 /* Counter record. */
457 pos += store_gcov_u32(buffer, pos,
458 GCOV_TAG_FOR_COUNTER(ct_idx));
459 pos += store_gcov_u32(buffer, pos, ci_ptr->num * 2);
460
461 for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
462 pos += store_gcov_u64(buffer, pos,
463 ci_ptr->values[cv_idx]);
464 }
465
466 ci_ptr++;
467 }
468 }
469
470 return pos;
471}
472
473/**
474 * gcov_iter_new - allocate and initialize profiling data iterator
475 * @info: profiling data set to be iterated
476 *
477 * Return file iterator on success, %NULL otherwise.
478 */
479struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
480{
481 struct gcov_iterator *iter;
482
483 iter = kzalloc(sizeof(struct gcov_iterator), GFP_KERNEL);
484 if (!iter)
485 goto err_free;
486
487 iter->info = info;
488 /* Dry-run to get the actual buffer size. */
489 iter->size = convert_to_gcda(NULL, info);
490 iter->buffer = vmalloc(iter->size);
491 if (!iter->buffer)
492 goto err_free;
493
494 convert_to_gcda(iter->buffer, info);
495
496 return iter;
497
498err_free:
499 kfree(iter);
500 return NULL;
501}
502
503
504/**
505 * gcov_iter_get_info - return profiling data set for given file iterator
506 * @iter: file iterator
507 */
508void gcov_iter_free(struct gcov_iterator *iter)
509{
510 vfree(iter->buffer);
511 kfree(iter);
512}
513
514/**
515 * gcov_iter_get_info - return profiling data set for given file iterator
516 * @iter: file iterator
517 */
518struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter)
519{
520 return iter->info;
521}
522
523/**
524 * gcov_iter_start - reset file iterator to starting position
525 * @iter: file iterator
526 */
527void gcov_iter_start(struct gcov_iterator *iter)
528{
529 iter->pos = 0;
530}
531
532/**
533 * gcov_iter_next - advance file iterator to next logical record
534 * @iter: file iterator
535 *
536 * Return zero if new position is valid, non-zero if iterator has reached end.
537 */
538int gcov_iter_next(struct gcov_iterator *iter)
539{
540 if (iter->pos < iter->size)
541 iter->pos += ITER_STRIDE;
542
543 if (iter->pos >= iter->size)
544 return -EINVAL;
545
546 return 0;
547}
548
549/**
550 * gcov_iter_write - write data for current pos to seq_file
551 * @iter: file iterator
552 * @seq: seq_file handle
553 *
554 * Return zero on success, non-zero otherwise.
555 */
556int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq)
557{
558 size_t len;
559
560 if (iter->pos >= iter->size)
561 return -EINVAL;
562
563 len = ITER_STRIDE;
564 if (iter->pos + len > iter->size)
565 len = iter->size - iter->pos;
566
567 seq_write(seq, iter->buffer + iter->pos, len);
568
569 return 0;
570}