Loading...
Note: File does not exist in v6.2.
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * This code provides functions to handle gcc's profiling data format
4 * introduced with gcc 3.4. Future versions of gcc may change the gcov
5 * format (as happened before), so all format-specific information needs
6 * to be kept modular and easily exchangeable.
7 *
8 * This file is based on gcc-internal definitions. Functions and data
9 * structures are defined to be compatible with gcc counterparts.
10 * For a better understanding, refer to gcc source: gcc/gcov-io.h.
11 *
12 * Copyright IBM Corp. 2009
13 * Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
14 *
15 * Uses gcc-internal data definitions.
16 */
17
18#include <linux/errno.h>
19#include <linux/slab.h>
20#include <linux/string.h>
21#include <linux/seq_file.h>
22#include <linux/vmalloc.h>
23#include "gcov.h"
24
25#define GCOV_COUNTERS 5
26
27static struct gcov_info *gcov_info_head;
28
29/**
30 * struct gcov_fn_info - profiling meta data per function
31 * @ident: object file-unique function identifier
32 * @checksum: function checksum
33 * @n_ctrs: number of values per counter type belonging to this function
34 *
35 * This data is generated by gcc during compilation and doesn't change
36 * at run-time.
37 */
38struct gcov_fn_info {
39 unsigned int ident;
40 unsigned int checksum;
41 unsigned int n_ctrs[0];
42};
43
44/**
45 * struct gcov_ctr_info - profiling data per counter type
46 * @num: number of counter values for this type
47 * @values: array of counter values for this type
48 * @merge: merge function for counter values of this type (unused)
49 *
50 * This data is generated by gcc during compilation and doesn't change
51 * at run-time with the exception of the values array.
52 */
53struct gcov_ctr_info {
54 unsigned int num;
55 gcov_type *values;
56 void (*merge)(gcov_type *, unsigned int);
57};
58
59/**
60 * struct gcov_info - profiling data per object file
61 * @version: gcov version magic indicating the gcc version used for compilation
62 * @next: list head for a singly-linked list
63 * @stamp: time stamp
64 * @filename: name of the associated gcov data file
65 * @n_functions: number of instrumented functions
66 * @functions: function data
67 * @ctr_mask: mask specifying which counter types are active
68 * @counts: counter data per counter type
69 *
70 * This data is generated by gcc during compilation and doesn't change
71 * at run-time with the exception of the next pointer.
72 */
73struct gcov_info {
74 unsigned int version;
75 struct gcov_info *next;
76 unsigned int stamp;
77 const char *filename;
78 unsigned int n_functions;
79 const struct gcov_fn_info *functions;
80 unsigned int ctr_mask;
81 struct gcov_ctr_info counts[0];
82};
83
84/**
85 * gcov_info_filename - return info filename
86 * @info: profiling data set
87 */
88const char *gcov_info_filename(struct gcov_info *info)
89{
90 return info->filename;
91}
92
93/**
94 * gcov_info_version - return info version
95 * @info: profiling data set
96 */
97unsigned int gcov_info_version(struct gcov_info *info)
98{
99 return info->version;
100}
101
102/**
103 * gcov_info_next - return next profiling data set
104 * @info: profiling data set
105 *
106 * Returns next gcov_info following @info or first gcov_info in the chain if
107 * @info is %NULL.
108 */
109struct gcov_info *gcov_info_next(struct gcov_info *info)
110{
111 if (!info)
112 return gcov_info_head;
113
114 return info->next;
115}
116
117/**
118 * gcov_info_link - link/add profiling data set to the list
119 * @info: profiling data set
120 */
121void gcov_info_link(struct gcov_info *info)
122{
123 info->next = gcov_info_head;
124 gcov_info_head = info;
125}
126
127/**
128 * gcov_info_unlink - unlink/remove profiling data set from the list
129 * @prev: previous profiling data set
130 * @info: profiling data set
131 */
132void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
133{
134 if (prev)
135 prev->next = info->next;
136 else
137 gcov_info_head = info->next;
138}
139
140/* Symbolic links to be created for each profiling data file. */
141const struct gcov_link gcov_link[] = {
142 { OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
143 { 0, NULL},
144};
145
146/*
147 * Determine whether a counter is active. Based on gcc magic. Doesn't change
148 * at run-time.
149 */
150static int counter_active(struct gcov_info *info, unsigned int type)
151{
152 return (1 << type) & info->ctr_mask;
153}
154
155/* Determine number of active counters. Based on gcc magic. */
156static unsigned int num_counter_active(struct gcov_info *info)
157{
158 unsigned int i;
159 unsigned int result = 0;
160
161 for (i = 0; i < GCOV_COUNTERS; i++) {
162 if (counter_active(info, i))
163 result++;
164 }
165 return result;
166}
167
168/**
169 * gcov_info_reset - reset profiling data to zero
170 * @info: profiling data set
171 */
172void gcov_info_reset(struct gcov_info *info)
173{
174 unsigned int active = num_counter_active(info);
175 unsigned int i;
176
177 for (i = 0; i < active; i++) {
178 memset(info->counts[i].values, 0,
179 info->counts[i].num * sizeof(gcov_type));
180 }
181}
182
183/**
184 * gcov_info_is_compatible - check if profiling data can be added
185 * @info1: first profiling data set
186 * @info2: second profiling data set
187 *
188 * Returns non-zero if profiling data can be added, zero otherwise.
189 */
190int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
191{
192 return (info1->stamp == info2->stamp);
193}
194
195/**
196 * gcov_info_add - add up profiling data
197 * @dest: profiling data set to which data is added
198 * @source: profiling data set which is added
199 *
200 * Adds profiling counts of @source to @dest.
201 */
202void gcov_info_add(struct gcov_info *dest, struct gcov_info *source)
203{
204 unsigned int i;
205 unsigned int j;
206
207 for (i = 0; i < num_counter_active(dest); i++) {
208 for (j = 0; j < dest->counts[i].num; j++) {
209 dest->counts[i].values[j] +=
210 source->counts[i].values[j];
211 }
212 }
213}
214
215/* Get size of function info entry. Based on gcc magic. */
216static size_t get_fn_size(struct gcov_info *info)
217{
218 size_t size;
219
220 size = sizeof(struct gcov_fn_info) + num_counter_active(info) *
221 sizeof(unsigned int);
222 if (__alignof__(struct gcov_fn_info) > sizeof(unsigned int))
223 size = ALIGN(size, __alignof__(struct gcov_fn_info));
224 return size;
225}
226
227/* Get address of function info entry. Based on gcc magic. */
228static struct gcov_fn_info *get_fn_info(struct gcov_info *info, unsigned int fn)
229{
230 return (struct gcov_fn_info *)
231 ((char *) info->functions + fn * get_fn_size(info));
232}
233
234/**
235 * gcov_info_dup - duplicate profiling data set
236 * @info: profiling data set to duplicate
237 *
238 * Return newly allocated duplicate on success, %NULL on error.
239 */
240struct gcov_info *gcov_info_dup(struct gcov_info *info)
241{
242 struct gcov_info *dup;
243 unsigned int i;
244 unsigned int active;
245
246 /* Duplicate gcov_info. */
247 active = num_counter_active(info);
248 dup = kzalloc(sizeof(struct gcov_info) +
249 sizeof(struct gcov_ctr_info) * active, GFP_KERNEL);
250 if (!dup)
251 return NULL;
252 dup->version = info->version;
253 dup->stamp = info->stamp;
254 dup->n_functions = info->n_functions;
255 dup->ctr_mask = info->ctr_mask;
256 /* Duplicate filename. */
257 dup->filename = kstrdup(info->filename, GFP_KERNEL);
258 if (!dup->filename)
259 goto err_free;
260 /* Duplicate table of functions. */
261 dup->functions = kmemdup(info->functions, info->n_functions *
262 get_fn_size(info), GFP_KERNEL);
263 if (!dup->functions)
264 goto err_free;
265 /* Duplicate counter arrays. */
266 for (i = 0; i < active ; i++) {
267 struct gcov_ctr_info *ctr = &info->counts[i];
268 size_t size = ctr->num * sizeof(gcov_type);
269
270 dup->counts[i].num = ctr->num;
271 dup->counts[i].merge = ctr->merge;
272 dup->counts[i].values = vmalloc(size);
273 if (!dup->counts[i].values)
274 goto err_free;
275 memcpy(dup->counts[i].values, ctr->values, size);
276 }
277 return dup;
278
279err_free:
280 gcov_info_free(dup);
281 return NULL;
282}
283
284/**
285 * gcov_info_free - release memory for profiling data set duplicate
286 * @info: profiling data set duplicate to free
287 */
288void gcov_info_free(struct gcov_info *info)
289{
290 unsigned int active = num_counter_active(info);
291 unsigned int i;
292
293 for (i = 0; i < active ; i++)
294 vfree(info->counts[i].values);
295 kfree(info->functions);
296 kfree(info->filename);
297 kfree(info);
298}
299
300/**
301 * struct type_info - iterator helper array
302 * @ctr_type: counter type
303 * @offset: index of the first value of the current function for this type
304 *
305 * This array is needed to convert the in-memory data format into the in-file
306 * data format:
307 *
308 * In-memory:
309 * for each counter type
310 * for each function
311 * values
312 *
313 * In-file:
314 * for each function
315 * for each counter type
316 * values
317 *
318 * See gcc source gcc/gcov-io.h for more information on data organization.
319 */
320struct type_info {
321 int ctr_type;
322 unsigned int offset;
323};
324
325/**
326 * struct gcov_iterator - specifies current file position in logical records
327 * @info: associated profiling data
328 * @record: record type
329 * @function: function number
330 * @type: counter type
331 * @count: index into values array
332 * @num_types: number of counter types
333 * @type_info: helper array to get values-array offset for current function
334 */
335struct gcov_iterator {
336 struct gcov_info *info;
337
338 int record;
339 unsigned int function;
340 unsigned int type;
341 unsigned int count;
342
343 int num_types;
344 struct type_info type_info[0];
345};
346
347static struct gcov_fn_info *get_func(struct gcov_iterator *iter)
348{
349 return get_fn_info(iter->info, iter->function);
350}
351
352static struct type_info *get_type(struct gcov_iterator *iter)
353{
354 return &iter->type_info[iter->type];
355}
356
357/**
358 * gcov_iter_new - allocate and initialize profiling data iterator
359 * @info: profiling data set to be iterated
360 *
361 * Return file iterator on success, %NULL otherwise.
362 */
363struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
364{
365 struct gcov_iterator *iter;
366
367 iter = kzalloc(sizeof(struct gcov_iterator) +
368 num_counter_active(info) * sizeof(struct type_info),
369 GFP_KERNEL);
370 if (iter)
371 iter->info = info;
372
373 return iter;
374}
375
376/**
377 * gcov_iter_free - release memory for iterator
378 * @iter: file iterator to free
379 */
380void gcov_iter_free(struct gcov_iterator *iter)
381{
382 kfree(iter);
383}
384
385/**
386 * gcov_iter_get_info - return profiling data set for given file iterator
387 * @iter: file iterator
388 */
389struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter)
390{
391 return iter->info;
392}
393
394/**
395 * gcov_iter_start - reset file iterator to starting position
396 * @iter: file iterator
397 */
398void gcov_iter_start(struct gcov_iterator *iter)
399{
400 int i;
401
402 iter->record = 0;
403 iter->function = 0;
404 iter->type = 0;
405 iter->count = 0;
406 iter->num_types = 0;
407 for (i = 0; i < GCOV_COUNTERS; i++) {
408 if (counter_active(iter->info, i)) {
409 iter->type_info[iter->num_types].ctr_type = i;
410 iter->type_info[iter->num_types++].offset = 0;
411 }
412 }
413}
414
415/* Mapping of logical record number to actual file content. */
416#define RECORD_FILE_MAGIC 0
417#define RECORD_GCOV_VERSION 1
418#define RECORD_TIME_STAMP 2
419#define RECORD_FUNCTION_TAG 3
420#define RECORD_FUNCTON_TAG_LEN 4
421#define RECORD_FUNCTION_IDENT 5
422#define RECORD_FUNCTION_CHECK 6
423#define RECORD_COUNT_TAG 7
424#define RECORD_COUNT_LEN 8
425#define RECORD_COUNT 9
426
427/**
428 * gcov_iter_next - advance file iterator to next logical record
429 * @iter: file iterator
430 *
431 * Return zero if new position is valid, non-zero if iterator has reached end.
432 */
433int gcov_iter_next(struct gcov_iterator *iter)
434{
435 switch (iter->record) {
436 case RECORD_FILE_MAGIC:
437 case RECORD_GCOV_VERSION:
438 case RECORD_FUNCTION_TAG:
439 case RECORD_FUNCTON_TAG_LEN:
440 case RECORD_FUNCTION_IDENT:
441 case RECORD_COUNT_TAG:
442 /* Advance to next record */
443 iter->record++;
444 break;
445 case RECORD_COUNT:
446 /* Advance to next count */
447 iter->count++;
448 /* fall through */
449 case RECORD_COUNT_LEN:
450 if (iter->count < get_func(iter)->n_ctrs[iter->type]) {
451 iter->record = 9;
452 break;
453 }
454 /* Advance to next counter type */
455 get_type(iter)->offset += iter->count;
456 iter->count = 0;
457 iter->type++;
458 /* fall through */
459 case RECORD_FUNCTION_CHECK:
460 if (iter->type < iter->num_types) {
461 iter->record = 7;
462 break;
463 }
464 /* Advance to next function */
465 iter->type = 0;
466 iter->function++;
467 /* fall through */
468 case RECORD_TIME_STAMP:
469 if (iter->function < iter->info->n_functions)
470 iter->record = 3;
471 else
472 iter->record = -1;
473 break;
474 }
475 /* Check for EOF. */
476 if (iter->record == -1)
477 return -EINVAL;
478 else
479 return 0;
480}
481
482/**
483 * seq_write_gcov_u32 - write 32 bit number in gcov format to seq_file
484 * @seq: seq_file handle
485 * @v: value to be stored
486 *
487 * Number format defined by gcc: numbers are recorded in the 32 bit
488 * unsigned binary form of the endianness of the machine generating the
489 * file.
490 */
491static int seq_write_gcov_u32(struct seq_file *seq, u32 v)
492{
493 return seq_write(seq, &v, sizeof(v));
494}
495
496/**
497 * seq_write_gcov_u64 - write 64 bit number in gcov format to seq_file
498 * @seq: seq_file handle
499 * @v: value to be stored
500 *
501 * Number format defined by gcc: numbers are recorded in the 32 bit
502 * unsigned binary form of the endianness of the machine generating the
503 * file. 64 bit numbers are stored as two 32 bit numbers, the low part
504 * first.
505 */
506static int seq_write_gcov_u64(struct seq_file *seq, u64 v)
507{
508 u32 data[2];
509
510 data[0] = (v & 0xffffffffUL);
511 data[1] = (v >> 32);
512 return seq_write(seq, data, sizeof(data));
513}
514
515/**
516 * gcov_iter_write - write data for current pos to seq_file
517 * @iter: file iterator
518 * @seq: seq_file handle
519 *
520 * Return zero on success, non-zero otherwise.
521 */
522int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq)
523{
524 int rc = -EINVAL;
525
526 switch (iter->record) {
527 case RECORD_FILE_MAGIC:
528 rc = seq_write_gcov_u32(seq, GCOV_DATA_MAGIC);
529 break;
530 case RECORD_GCOV_VERSION:
531 rc = seq_write_gcov_u32(seq, iter->info->version);
532 break;
533 case RECORD_TIME_STAMP:
534 rc = seq_write_gcov_u32(seq, iter->info->stamp);
535 break;
536 case RECORD_FUNCTION_TAG:
537 rc = seq_write_gcov_u32(seq, GCOV_TAG_FUNCTION);
538 break;
539 case RECORD_FUNCTON_TAG_LEN:
540 rc = seq_write_gcov_u32(seq, 2);
541 break;
542 case RECORD_FUNCTION_IDENT:
543 rc = seq_write_gcov_u32(seq, get_func(iter)->ident);
544 break;
545 case RECORD_FUNCTION_CHECK:
546 rc = seq_write_gcov_u32(seq, get_func(iter)->checksum);
547 break;
548 case RECORD_COUNT_TAG:
549 rc = seq_write_gcov_u32(seq,
550 GCOV_TAG_FOR_COUNTER(get_type(iter)->ctr_type));
551 break;
552 case RECORD_COUNT_LEN:
553 rc = seq_write_gcov_u32(seq,
554 get_func(iter)->n_ctrs[iter->type] * 2);
555 break;
556 case RECORD_COUNT:
557 rc = seq_write_gcov_u64(seq,
558 iter->info->counts[iter->type].
559 values[iter->count + get_type(iter)->offset]);
560 break;
561 }
562 return rc;
563}