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>
22 #define GCOV_COUNTERS 8
24 #define GCOV_COUNTERS 9
25 #elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)
26 #define GCOV_COUNTERS 10
28 #define GCOV_COUNTERS 9
31 #define GCOV_TAG_FUNCTION_LENGTH 3
33 /* Since GCC 12.1 sizes are in BYTES and not in WORDS (4B). */
35 #define GCOV_UNIT_SIZE 4
37 #define GCOV_UNIT_SIZE 1
40 static struct gcov_info *gcov_info_head;
43 * struct gcov_ctr_info - information about counters for a single function
44 * @num: number of counter values for this type
45 * @values: array of counter values for this type
47 * This data is generated by gcc during compilation and doesn't change
48 * at run-time with the exception of the values array.
50 struct gcov_ctr_info {
56 * struct gcov_fn_info - profiling meta data per function
58 * @ident: unique ident of function
59 * @lineno_checksum: function lineo_checksum
60 * @cfg_checksum: function cfg checksum
61 * @ctrs: instrumented counters
63 * This data is generated by gcc during compilation and doesn't change
66 * Information about a single function. This uses the trailing array
67 * idiom. The number of counters is determined from the merge pointer
68 * array in gcov_info. The key is used to detect which of a set of
69 * comdat functions was selected -- it points to the gcov_info object
70 * of the object file containing the selected comdat function.
73 const struct gcov_info *key;
75 unsigned int lineno_checksum;
76 unsigned int cfg_checksum;
77 struct gcov_ctr_info ctrs[];
81 * struct gcov_info - profiling data per object file
82 * @version: gcov version magic indicating the gcc version used for compilation
83 * @next: list head for a singly-linked list
84 * @stamp: uniquifying time stamp
85 * @checksum: unique object checksum
86 * @filename: name of the associated gcov data file
87 * @merge: merge functions (null for unused counter type)
88 * @n_functions: number of instrumented functions
89 * @functions: pointer to pointers to function information
91 * This data is generated by gcc during compilation and doesn't change
92 * at run-time with the exception of the next pointer.
96 struct gcov_info *next;
98 /* Since GCC 12.1 a checksum field is added. */
100 unsigned int checksum;
102 const char *filename;
103 void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int);
104 unsigned int n_functions;
105 struct gcov_fn_info **functions;
109 * gcov_info_filename - return info filename
110 * @info: profiling data set
112 const char *gcov_info_filename(struct gcov_info *info)
114 return info->filename;
118 * gcov_info_version - return info version
119 * @info: profiling data set
121 unsigned int gcov_info_version(struct gcov_info *info)
123 return info->version;
127 * gcov_info_next - return next profiling data set
128 * @info: profiling data set
130 * Returns next gcov_info following @info or first gcov_info in the chain if
133 struct gcov_info *gcov_info_next(struct gcov_info *info)
136 return gcov_info_head;
142 * gcov_info_link - link/add profiling data set to the list
143 * @info: profiling data set
145 void gcov_info_link(struct gcov_info *info)
147 info->next = gcov_info_head;
148 gcov_info_head = info;
152 * gcov_info_unlink - unlink/remove profiling data set from the list
153 * @prev: previous profiling data set
154 * @info: profiling data set
156 void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
159 prev->next = info->next;
161 gcov_info_head = info->next;
165 * gcov_info_within_module - check if a profiling data set belongs to a module
166 * @info: profiling data set
169 * Returns true if profiling data belongs module, false otherwise.
171 bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
173 return within_module((unsigned long)info, mod);
176 /* Symbolic links to be created for each profiling data file. */
177 const struct gcov_link gcov_link[] = {
178 { OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
183 * Determine whether a counter is active. Doesn't change at run-time.
185 static int counter_active(struct gcov_info *info, unsigned int type)
187 return info->merge[type] ? 1 : 0;
190 /* Determine number of active counters. Based on gcc magic. */
191 static unsigned int num_counter_active(struct gcov_info *info)
194 unsigned int result = 0;
196 for (i = 0; i < GCOV_COUNTERS; i++) {
197 if (counter_active(info, i))
204 * gcov_info_reset - reset profiling data to zero
205 * @info: profiling data set
207 void gcov_info_reset(struct gcov_info *info)
209 struct gcov_ctr_info *ci_ptr;
213 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
214 ci_ptr = info->functions[fi_idx]->ctrs;
216 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
217 if (!counter_active(info, ct_idx))
220 memset(ci_ptr->values, 0,
221 sizeof(gcov_type) * ci_ptr->num);
228 * gcov_info_is_compatible - check if profiling data can be added
229 * @info1: first profiling data set
230 * @info2: second profiling data set
232 * Returns non-zero if profiling data can be added, zero otherwise.
234 int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
236 return (info1->stamp == info2->stamp);
240 * gcov_info_add - add up profiling data
241 * @dst: profiling data set to which data is added
242 * @src: profiling data set which is added
244 * Adds profiling counts of @src to @dst.
246 void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
248 struct gcov_ctr_info *dci_ptr;
249 struct gcov_ctr_info *sci_ptr;
252 unsigned int val_idx;
254 for (fi_idx = 0; fi_idx < src->n_functions; fi_idx++) {
255 dci_ptr = dst->functions[fi_idx]->ctrs;
256 sci_ptr = src->functions[fi_idx]->ctrs;
258 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
259 if (!counter_active(src, ct_idx))
262 for (val_idx = 0; val_idx < sci_ptr->num; val_idx++)
263 dci_ptr->values[val_idx] +=
264 sci_ptr->values[val_idx];
273 * gcov_info_dup - duplicate profiling data set
274 * @info: profiling data set to duplicate
276 * Return newly allocated duplicate on success, %NULL on error.
278 struct gcov_info *gcov_info_dup(struct gcov_info *info)
280 struct gcov_info *dup;
281 struct gcov_ctr_info *dci_ptr; /* dst counter info */
282 struct gcov_ctr_info *sci_ptr; /* src counter info */
284 unsigned int fi_idx; /* function info idx */
285 unsigned int ct_idx; /* counter type idx */
286 size_t fi_size; /* function info size */
287 size_t cv_size; /* counter values size */
289 dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
294 dup->filename = NULL;
295 dup->functions = NULL;
297 dup->filename = kstrdup(info->filename, GFP_KERNEL);
301 dup->functions = kcalloc(info->n_functions,
302 sizeof(struct gcov_fn_info *), GFP_KERNEL);
306 active = num_counter_active(info);
307 fi_size = sizeof(struct gcov_fn_info);
308 fi_size += sizeof(struct gcov_ctr_info) * active;
310 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
311 dup->functions[fi_idx] = kzalloc(fi_size, GFP_KERNEL);
312 if (!dup->functions[fi_idx])
315 *(dup->functions[fi_idx]) = *(info->functions[fi_idx]);
317 sci_ptr = info->functions[fi_idx]->ctrs;
318 dci_ptr = dup->functions[fi_idx]->ctrs;
320 for (ct_idx = 0; ct_idx < active; ct_idx++) {
322 cv_size = sizeof(gcov_type) * sci_ptr->num;
324 dci_ptr->values = kvmalloc(cv_size, GFP_KERNEL);
326 if (!dci_ptr->values)
329 dci_ptr->num = sci_ptr->num;
330 memcpy(dci_ptr->values, sci_ptr->values, cv_size);
344 * gcov_info_free - release memory for profiling data set duplicate
345 * @info: profiling data set duplicate to free
347 void gcov_info_free(struct gcov_info *info)
352 struct gcov_ctr_info *ci_ptr;
354 if (!info->functions)
357 active = num_counter_active(info);
359 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
360 if (!info->functions[fi_idx])
363 ci_ptr = info->functions[fi_idx]->ctrs;
365 for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++)
366 kvfree(ci_ptr->values);
368 kfree(info->functions[fi_idx]);
372 kfree(info->functions);
373 kfree(info->filename);
378 * convert_to_gcda - convert profiling data set to gcda file format
379 * @buffer: the buffer to store file data or %NULL if no data should be stored
380 * @info: profiling data set to be converted
382 * Returns the number of bytes that were/would have been stored into the buffer.
384 size_t convert_to_gcda(char *buffer, struct gcov_info *info)
386 struct gcov_fn_info *fi_ptr;
387 struct gcov_ctr_info *ci_ptr;
394 pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
395 pos += store_gcov_u32(buffer, pos, info->version);
396 pos += store_gcov_u32(buffer, pos, info->stamp);
399 /* Use zero as checksum of the compilation unit. */
400 pos += store_gcov_u32(buffer, pos, 0);
403 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
404 fi_ptr = info->functions[fi_idx];
406 /* Function record. */
407 pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
408 pos += store_gcov_u32(buffer, pos,
409 GCOV_TAG_FUNCTION_LENGTH * GCOV_UNIT_SIZE);
410 pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
411 pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum);
412 pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
414 ci_ptr = fi_ptr->ctrs;
416 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
417 if (!counter_active(info, ct_idx))
420 /* Counter record. */
421 pos += store_gcov_u32(buffer, pos,
422 GCOV_TAG_FOR_COUNTER(ct_idx));
423 pos += store_gcov_u32(buffer, pos,
424 ci_ptr->num * 2 * GCOV_UNIT_SIZE);
426 for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
427 pos += store_gcov_u64(buffer, pos,
428 ci_ptr->values[cv_idx]);