1 // SPDX-License-Identifier: GPL-2.0
3 * This code provides functions to handle gcc's profiling data format
4 * introduced with gcc 4.7.
6 * This file is based heavily on gcc_3_4.c file.
8 * For a better understanding, refer to gcc source:
12 * Uses gcc-internal data definitions.
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>
23 #define GCOV_COUNTERS 8
25 #define GCOV_COUNTERS 9
26 #elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)
27 #define GCOV_COUNTERS 10
28 #elif __GNUC__ == 4 && __GNUC_MINOR__ >= 9
29 #define GCOV_COUNTERS 9
31 #define GCOV_COUNTERS 8
34 #define GCOV_TAG_FUNCTION_LENGTH 3
36 static struct gcov_info *gcov_info_head;
39 * struct gcov_ctr_info - information about counters for a single function
40 * @num: number of counter values for this type
41 * @values: array of counter values for this type
43 * This data is generated by gcc during compilation and doesn't change
44 * at run-time with the exception of the values array.
46 struct gcov_ctr_info {
52 * struct gcov_fn_info - profiling meta data per function
54 * @ident: unique ident of function
55 * @lineno_checksum: function lineo_checksum
56 * @cfg_checksum: function cfg checksum
57 * @ctrs: instrumented counters
59 * This data is generated by gcc during compilation and doesn't change
62 * Information about a single function. This uses the trailing array
63 * idiom. The number of counters is determined from the merge pointer
64 * array in gcov_info. The key is used to detect which of a set of
65 * comdat functions was selected -- it points to the gcov_info object
66 * of the object file containing the selected comdat function.
69 const struct gcov_info *key;
71 unsigned int lineno_checksum;
72 unsigned int cfg_checksum;
73 struct gcov_ctr_info ctrs[0];
77 * struct gcov_info - profiling data per object file
78 * @version: gcov version magic indicating the gcc version used for compilation
79 * @next: list head for a singly-linked list
80 * @stamp: uniquifying time stamp
81 * @filename: name of the associated gcov data file
82 * @merge: merge functions (null for unused counter type)
83 * @n_functions: number of instrumented functions
84 * @functions: pointer to pointers to function information
86 * This data is generated by gcc during compilation and doesn't change
87 * at run-time with the exception of the next pointer.
91 struct gcov_info *next;
94 void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int);
95 unsigned int n_functions;
96 struct gcov_fn_info **functions;
100 * gcov_info_filename - return info filename
101 * @info: profiling data set
103 const char *gcov_info_filename(struct gcov_info *info)
105 return info->filename;
109 * gcov_info_version - return info version
110 * @info: profiling data set
112 unsigned int gcov_info_version(struct gcov_info *info)
114 return info->version;
118 * gcov_info_next - return next profiling data set
119 * @info: profiling data set
121 * Returns next gcov_info following @info or first gcov_info in the chain if
124 struct gcov_info *gcov_info_next(struct gcov_info *info)
127 return gcov_info_head;
133 * gcov_info_link - link/add profiling data set to the list
134 * @info: profiling data set
136 void gcov_info_link(struct gcov_info *info)
138 info->next = gcov_info_head;
139 gcov_info_head = info;
143 * gcov_info_unlink - unlink/remove profiling data set from the list
144 * @prev: previous profiling data set
145 * @info: profiling data set
147 void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
150 prev->next = info->next;
152 gcov_info_head = info->next;
155 /* Symbolic links to be created for each profiling data file. */
156 const struct gcov_link gcov_link[] = {
157 { OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
162 * Determine whether a counter is active. Doesn't change at run-time.
164 static int counter_active(struct gcov_info *info, unsigned int type)
166 return info->merge[type] ? 1 : 0;
169 /* Determine number of active counters. Based on gcc magic. */
170 static unsigned int num_counter_active(struct gcov_info *info)
173 unsigned int result = 0;
175 for (i = 0; i < GCOV_COUNTERS; i++) {
176 if (counter_active(info, i))
183 * gcov_info_reset - reset profiling data to zero
184 * @info: profiling data set
186 void gcov_info_reset(struct gcov_info *info)
188 struct gcov_ctr_info *ci_ptr;
192 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
193 ci_ptr = info->functions[fi_idx]->ctrs;
195 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
196 if (!counter_active(info, ct_idx))
199 memset(ci_ptr->values, 0,
200 sizeof(gcov_type) * ci_ptr->num);
207 * gcov_info_is_compatible - check if profiling data can be added
208 * @info1: first profiling data set
209 * @info2: second profiling data set
211 * Returns non-zero if profiling data can be added, zero otherwise.
213 int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
215 return (info1->stamp == info2->stamp);
219 * gcov_info_add - add up profiling data
220 * @dest: profiling data set to which data is added
221 * @source: profiling data set which is added
223 * Adds profiling counts of @source to @dest.
225 void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
227 struct gcov_ctr_info *dci_ptr;
228 struct gcov_ctr_info *sci_ptr;
231 unsigned int val_idx;
233 for (fi_idx = 0; fi_idx < src->n_functions; fi_idx++) {
234 dci_ptr = dst->functions[fi_idx]->ctrs;
235 sci_ptr = src->functions[fi_idx]->ctrs;
237 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
238 if (!counter_active(src, ct_idx))
241 for (val_idx = 0; val_idx < sci_ptr->num; val_idx++)
242 dci_ptr->values[val_idx] +=
243 sci_ptr->values[val_idx];
252 * gcov_info_dup - duplicate profiling data set
253 * @info: profiling data set to duplicate
255 * Return newly allocated duplicate on success, %NULL on error.
257 struct gcov_info *gcov_info_dup(struct gcov_info *info)
259 struct gcov_info *dup;
260 struct gcov_ctr_info *dci_ptr; /* dst counter info */
261 struct gcov_ctr_info *sci_ptr; /* src counter info */
263 unsigned int fi_idx; /* function info idx */
264 unsigned int ct_idx; /* counter type idx */
265 size_t fi_size; /* function info size */
266 size_t cv_size; /* counter values size */
268 dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
273 dup->filename = NULL;
274 dup->functions = NULL;
276 dup->filename = kstrdup(info->filename, GFP_KERNEL);
280 dup->functions = kcalloc(info->n_functions,
281 sizeof(struct gcov_fn_info *), GFP_KERNEL);
285 active = num_counter_active(info);
286 fi_size = sizeof(struct gcov_fn_info);
287 fi_size += sizeof(struct gcov_ctr_info) * active;
289 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
290 dup->functions[fi_idx] = kzalloc(fi_size, GFP_KERNEL);
291 if (!dup->functions[fi_idx])
294 *(dup->functions[fi_idx]) = *(info->functions[fi_idx]);
296 sci_ptr = info->functions[fi_idx]->ctrs;
297 dci_ptr = dup->functions[fi_idx]->ctrs;
299 for (ct_idx = 0; ct_idx < active; ct_idx++) {
301 cv_size = sizeof(gcov_type) * sci_ptr->num;
303 dci_ptr->values = vmalloc(cv_size);
305 if (!dci_ptr->values)
308 dci_ptr->num = sci_ptr->num;
309 memcpy(dci_ptr->values, sci_ptr->values, cv_size);
323 * gcov_info_free - release memory for profiling data set duplicate
324 * @info: profiling data set duplicate to free
326 void gcov_info_free(struct gcov_info *info)
331 struct gcov_ctr_info *ci_ptr;
333 if (!info->functions)
336 active = num_counter_active(info);
338 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
339 if (!info->functions[fi_idx])
342 ci_ptr = info->functions[fi_idx]->ctrs;
344 for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++)
345 vfree(ci_ptr->values);
347 kfree(info->functions[fi_idx]);
351 kfree(info->functions);
352 kfree(info->filename);
356 #define ITER_STRIDE PAGE_SIZE
359 * struct gcov_iterator - specifies current file position in logical records
360 * @info: associated profiling data
361 * @buffer: buffer containing file data
362 * @size: size of buffer
363 * @pos: current position in file
365 struct gcov_iterator {
366 struct gcov_info *info;
373 * store_gcov_u32 - store 32 bit number in gcov format to buffer
374 * @buffer: target buffer or NULL
375 * @off: offset into the buffer
376 * @v: value to be stored
378 * Number format defined by gcc: numbers are recorded in the 32 bit
379 * unsigned binary form of the endianness of the machine generating the
380 * file. Returns the number of bytes stored. If @buffer is %NULL, doesn't
383 static size_t store_gcov_u32(void *buffer, size_t off, u32 v)
392 return sizeof(*data);
396 * store_gcov_u64 - store 64 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
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. 64 bit numbers are stored as two 32 bit numbers, the low part
404 * first. Returns the number of bytes stored. If @buffer is %NULL, doesn't store
407 static size_t store_gcov_u64(void *buffer, size_t off, u64 v)
414 data[0] = (v & 0xffffffffUL);
418 return sizeof(*data) * 2;
422 * convert_to_gcda - convert profiling data set to gcda file format
423 * @buffer: the buffer to store file data or %NULL if no data should be stored
424 * @info: profiling data set to be converted
426 * Returns the number of bytes that were/would have been stored into the buffer.
428 static size_t convert_to_gcda(char *buffer, struct gcov_info *info)
430 struct gcov_fn_info *fi_ptr;
431 struct gcov_ctr_info *ci_ptr;
438 pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
439 pos += store_gcov_u32(buffer, pos, info->version);
440 pos += store_gcov_u32(buffer, pos, info->stamp);
442 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
443 fi_ptr = info->functions[fi_idx];
445 /* Function record. */
446 pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
447 pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION_LENGTH);
448 pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
449 pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum);
450 pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
452 ci_ptr = fi_ptr->ctrs;
454 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
455 if (!counter_active(info, ct_idx))
458 /* Counter record. */
459 pos += store_gcov_u32(buffer, pos,
460 GCOV_TAG_FOR_COUNTER(ct_idx));
461 pos += store_gcov_u32(buffer, pos, ci_ptr->num * 2);
463 for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
464 pos += store_gcov_u64(buffer, pos,
465 ci_ptr->values[cv_idx]);
476 * gcov_iter_new - allocate and initialize profiling data iterator
477 * @info: profiling data set to be iterated
479 * Return file iterator on success, %NULL otherwise.
481 struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
483 struct gcov_iterator *iter;
485 iter = kzalloc(sizeof(struct gcov_iterator), GFP_KERNEL);
490 /* Dry-run to get the actual buffer size. */
491 iter->size = convert_to_gcda(NULL, info);
492 iter->buffer = vmalloc(iter->size);
496 convert_to_gcda(iter->buffer, info);
507 * gcov_iter_get_info - return profiling data set for given file iterator
508 * @iter: file iterator
510 void gcov_iter_free(struct gcov_iterator *iter)
517 * gcov_iter_get_info - return profiling data set for given file iterator
518 * @iter: file iterator
520 struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter)
526 * gcov_iter_start - reset file iterator to starting position
527 * @iter: file iterator
529 void gcov_iter_start(struct gcov_iterator *iter)
535 * gcov_iter_next - advance file iterator to next logical record
536 * @iter: file iterator
538 * Return zero if new position is valid, non-zero if iterator has reached end.
540 int gcov_iter_next(struct gcov_iterator *iter)
542 if (iter->pos < iter->size)
543 iter->pos += ITER_STRIDE;
545 if (iter->pos >= iter->size)
552 * gcov_iter_write - write data for current pos to seq_file
553 * @iter: file iterator
554 * @seq: seq_file handle
556 * Return zero on success, non-zero otherwise.
558 int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq)
562 if (iter->pos >= iter->size)
566 if (iter->pos + len > iter->size)
567 len = iter->size - iter->pos;
569 seq_write(seq, iter->buffer + iter->pos, len);