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