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/mm.h>
19#include "gcov.h"
20
21#if (__GNUC__ >= 10)
22#define GCOV_COUNTERS 8
23#elif (__GNUC__ >= 7)
24#define GCOV_COUNTERS 9
25#elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)
26#define GCOV_COUNTERS 10
27#else
28#define GCOV_COUNTERS 9
29#endif
30
31#define GCOV_TAG_FUNCTION_LENGTH 3
32
33/* Since GCC 12.1 sizes are in BYTES and not in WORDS (4B). */
34#if (__GNUC__ >= 12)
35#define GCOV_UNIT_SIZE 4
36#else
37#define GCOV_UNIT_SIZE 1
38#endif
39
40static struct gcov_info *gcov_info_head;
41
42/**
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
46 *
47 * This data is generated by gcc during compilation and doesn't change
48 * at run-time with the exception of the values array.
49 */
50struct gcov_ctr_info {
51 unsigned int num;
52 gcov_type *values;
53};
54
55/**
56 * struct gcov_fn_info - profiling meta data per function
57 * @key: comdat key
58 * @ident: unique ident of function
59 * @lineno_checksum: function lineo_checksum
60 * @cfg_checksum: function cfg checksum
61 * @ctrs: instrumented counters
62 *
63 * This data is generated by gcc during compilation and doesn't change
64 * at run-time.
65 *
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.
71 */
72struct gcov_fn_info {
73 const struct gcov_info *key;
74 unsigned int ident;
75 unsigned int lineno_checksum;
76 unsigned int cfg_checksum;
77 struct gcov_ctr_info ctrs[];
78};
79
80/**
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
90 *
91 * This data is generated by gcc during compilation and doesn't change
92 * at run-time with the exception of the next pointer.
93 */
94struct gcov_info {
95 unsigned int version;
96 struct gcov_info *next;
97 unsigned int stamp;
98 /* Since GCC 12.1 a checksum field is added. */
99#if (__GNUC__ >= 12)
100 unsigned int checksum;
101#endif
102 const char *filename;
103 void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int);
104 unsigned int n_functions;
105 struct gcov_fn_info **functions;
106};
107
108/**
109 * gcov_info_filename - return info filename
110 * @info: profiling data set
111 */
112const char *gcov_info_filename(struct gcov_info *info)
113{
114 return info->filename;
115}
116
117/**
118 * gcov_info_version - return info version
119 * @info: profiling data set
120 */
121unsigned int gcov_info_version(struct gcov_info *info)
122{
123 return info->version;
124}
125
126/**
127 * gcov_info_next - return next profiling data set
128 * @info: profiling data set
129 *
130 * Returns next gcov_info following @info or first gcov_info in the chain if
131 * @info is %NULL.
132 */
133struct gcov_info *gcov_info_next(struct gcov_info *info)
134{
135 if (!info)
136 return gcov_info_head;
137
138 return info->next;
139}
140
141/**
142 * gcov_info_link - link/add profiling data set to the list
143 * @info: profiling data set
144 */
145void gcov_info_link(struct gcov_info *info)
146{
147 info->next = gcov_info_head;
148 gcov_info_head = info;
149}
150
151/**
152 * gcov_info_unlink - unlink/remove profiling data set from the list
153 * @prev: previous profiling data set
154 * @info: profiling data set
155 */
156void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
157{
158 if (prev)
159 prev->next = info->next;
160 else
161 gcov_info_head = info->next;
162}
163
164/**
165 * gcov_info_within_module - check if a profiling data set belongs to a module
166 * @info: profiling data set
167 * @mod: module
168 *
169 * Returns true if profiling data belongs module, false otherwise.
170 */
171bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
172{
173 return within_module(addr: (unsigned long)info, mod);
174}
175
176/* Symbolic links to be created for each profiling data file. */
177const struct gcov_link gcov_link[] = {
178 { OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
179 { 0, NULL},
180};
181
182/*
183 * Determine whether a counter is active. Doesn't change at run-time.
184 */
185static int counter_active(struct gcov_info *info, unsigned int type)
186{
187 return info->merge[type] ? 1 : 0;
188}
189
190/* Determine number of active counters. Based on gcc magic. */
191static unsigned int num_counter_active(struct gcov_info *info)
192{
193 unsigned int i;
194 unsigned int result = 0;
195
196 for (i = 0; i < GCOV_COUNTERS; i++) {
197 if (counter_active(info, type: i))
198 result++;
199 }
200 return result;
201}
202
203/**
204 * gcov_info_reset - reset profiling data to zero
205 * @info: profiling data set
206 */
207void gcov_info_reset(struct gcov_info *info)
208{
209 struct gcov_ctr_info *ci_ptr;
210 unsigned int fi_idx;
211 unsigned int ct_idx;
212
213 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
214 ci_ptr = info->functions[fi_idx]->ctrs;
215
216 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
217 if (!counter_active(info, type: ct_idx))
218 continue;
219
220 memset(ci_ptr->values, 0,
221 sizeof(gcov_type) * ci_ptr->num);
222 ci_ptr++;
223 }
224 }
225}
226
227/**
228 * gcov_info_is_compatible - check if profiling data can be added
229 * @info1: first profiling data set
230 * @info2: second profiling data set
231 *
232 * Returns non-zero if profiling data can be added, zero otherwise.
233 */
234int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
235{
236 return (info1->stamp == info2->stamp);
237}
238
239/**
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
243 *
244 * Adds profiling counts of @src to @dst.
245 */
246void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
247{
248 struct gcov_ctr_info *dci_ptr;
249 struct gcov_ctr_info *sci_ptr;
250 unsigned int fi_idx;
251 unsigned int ct_idx;
252 unsigned int val_idx;
253
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;
257
258 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
259 if (!counter_active(info: src, type: ct_idx))
260 continue;
261
262 for (val_idx = 0; val_idx < sci_ptr->num; val_idx++)
263 dci_ptr->values[val_idx] +=
264 sci_ptr->values[val_idx];
265
266 dci_ptr++;
267 sci_ptr++;
268 }
269 }
270}
271
272/**
273 * gcov_info_dup - duplicate profiling data set
274 * @info: profiling data set to duplicate
275 *
276 * Return newly allocated duplicate on success, %NULL on error.
277 */
278struct gcov_info *gcov_info_dup(struct gcov_info *info)
279{
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 */
283 unsigned int active;
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 */
288
289 dup = kmemdup(p: info, size: sizeof(*dup), GFP_KERNEL);
290 if (!dup)
291 return NULL;
292
293 dup->next = NULL;
294 dup->filename = NULL;
295 dup->functions = NULL;
296
297 dup->filename = kstrdup(s: info->filename, GFP_KERNEL);
298 if (!dup->filename)
299 goto err_free;
300
301 dup->functions = kcalloc(n: info->n_functions,
302 size: sizeof(struct gcov_fn_info *), GFP_KERNEL);
303 if (!dup->functions)
304 goto err_free;
305
306 active = num_counter_active(info);
307 fi_size = sizeof(struct gcov_fn_info);
308 fi_size += sizeof(struct gcov_ctr_info) * active;
309
310 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
311 dup->functions[fi_idx] = kzalloc(size: fi_size, GFP_KERNEL);
312 if (!dup->functions[fi_idx])
313 goto err_free;
314
315 *(dup->functions[fi_idx]) = *(info->functions[fi_idx]);
316
317 sci_ptr = info->functions[fi_idx]->ctrs;
318 dci_ptr = dup->functions[fi_idx]->ctrs;
319
320 for (ct_idx = 0; ct_idx < active; ct_idx++) {
321
322 cv_size = sizeof(gcov_type) * sci_ptr->num;
323
324 dci_ptr->values = kvmalloc(size: cv_size, GFP_KERNEL);
325
326 if (!dci_ptr->values)
327 goto err_free;
328
329 dci_ptr->num = sci_ptr->num;
330 memcpy(dci_ptr->values, sci_ptr->values, cv_size);
331
332 sci_ptr++;
333 dci_ptr++;
334 }
335 }
336
337 return dup;
338err_free:
339 gcov_info_free(info: dup);
340 return NULL;
341}
342
343/**
344 * gcov_info_free - release memory for profiling data set duplicate
345 * @info: profiling data set duplicate to free
346 */
347void gcov_info_free(struct gcov_info *info)
348{
349 unsigned int active;
350 unsigned int fi_idx;
351 unsigned int ct_idx;
352 struct gcov_ctr_info *ci_ptr;
353
354 if (!info->functions)
355 goto free_info;
356
357 active = num_counter_active(info);
358
359 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
360 if (!info->functions[fi_idx])
361 continue;
362
363 ci_ptr = info->functions[fi_idx]->ctrs;
364
365 for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++)
366 kvfree(addr: ci_ptr->values);
367
368 kfree(objp: info->functions[fi_idx]);
369 }
370
371free_info:
372 kfree(objp: info->functions);
373 kfree(objp: info->filename);
374 kfree(objp: info);
375}
376
377/**
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
381 *
382 * Returns the number of bytes that were/would have been stored into the buffer.
383 */
384size_t convert_to_gcda(char *buffer, struct gcov_info *info)
385{
386 struct gcov_fn_info *fi_ptr;
387 struct gcov_ctr_info *ci_ptr;
388 unsigned int fi_idx;
389 unsigned int ct_idx;
390 unsigned int cv_idx;
391 size_t pos = 0;
392
393 /* File header. */
394 pos += store_gcov_u32(buffer, off: pos, GCOV_DATA_MAGIC);
395 pos += store_gcov_u32(buffer, off: pos, v: info->version);
396 pos += store_gcov_u32(buffer, off: pos, v: info->stamp);
397
398#if (__GNUC__ >= 12)
399 /* Use zero as checksum of the compilation unit. */
400 pos += store_gcov_u32(buffer, pos, 0);
401#endif
402
403 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
404 fi_ptr = info->functions[fi_idx];
405
406 /* Function record. */
407 pos += store_gcov_u32(buffer, off: pos, GCOV_TAG_FUNCTION);
408 pos += store_gcov_u32(buffer, off: pos,
409 GCOV_TAG_FUNCTION_LENGTH * GCOV_UNIT_SIZE);
410 pos += store_gcov_u32(buffer, off: pos, v: fi_ptr->ident);
411 pos += store_gcov_u32(buffer, off: pos, v: fi_ptr->lineno_checksum);
412 pos += store_gcov_u32(buffer, off: pos, v: fi_ptr->cfg_checksum);
413
414 ci_ptr = fi_ptr->ctrs;
415
416 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
417 if (!counter_active(info, type: ct_idx))
418 continue;
419
420 /* Counter record. */
421 pos += store_gcov_u32(buffer, off: pos,
422 GCOV_TAG_FOR_COUNTER(ct_idx));
423 pos += store_gcov_u32(buffer, off: pos,
424 v: ci_ptr->num * 2 * GCOV_UNIT_SIZE);
425
426 for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
427 pos += store_gcov_u64(buffer, off: pos,
428 v: ci_ptr->values[cv_idx]);
429 }
430
431 ci_ptr++;
432 }
433 }
434
435 return pos;
436}
437

source code of linux/kernel/gcov/gcc_4_7.c