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__ >= 14)
22 #define GCOV_COUNTERS 9
23 #elif (__GNUC__ >= 10)
24 #define GCOV_COUNTERS 8
25 #else
26 #define GCOV_COUNTERS 9
27 #endif
28
29 #define GCOV_TAG_FUNCTION_LENGTH 3
30
31 /* Since GCC 12.1 sizes are in BYTES and not in WORDS (4B). */
32 #if (__GNUC__ >= 12)
33 #define GCOV_UNIT_SIZE 4
34 #else
35 #define GCOV_UNIT_SIZE 1
36 #endif
37
38 static struct gcov_info *gcov_info_head;
39
40 /**
41 * struct gcov_ctr_info - information about counters for a single function
42 * @num: number of counter values for this type
43 * @values: array of counter values for this type
44 *
45 * This data is generated by gcc during compilation and doesn't change
46 * at run-time with the exception of the values array.
47 */
48 struct gcov_ctr_info {
49 unsigned int num;
50 gcov_type *values;
51 };
52
53 /**
54 * struct gcov_fn_info - profiling meta data per function
55 * @key: comdat key
56 * @ident: unique ident of function
57 * @lineno_checksum: function lineo_checksum
58 * @cfg_checksum: function cfg checksum
59 * @ctrs: instrumented counters
60 *
61 * This data is generated by gcc during compilation and doesn't change
62 * at run-time.
63 *
64 * Information about a single function. This uses the trailing array
65 * idiom. The number of counters is determined from the merge pointer
66 * array in gcov_info. The key is used to detect which of a set of
67 * comdat functions was selected -- it points to the gcov_info object
68 * of the object file containing the selected comdat function.
69 */
70 struct gcov_fn_info {
71 const struct gcov_info *key;
72 unsigned int ident;
73 unsigned int lineno_checksum;
74 unsigned int cfg_checksum;
75 struct gcov_ctr_info ctrs[];
76 };
77
78 /**
79 * struct gcov_info - profiling data per object file
80 * @version: gcov version magic indicating the gcc version used for compilation
81 * @next: list head for a singly-linked list
82 * @stamp: uniquifying time stamp
83 * @checksum: unique object checksum
84 * @filename: name of the associated gcov data file
85 * @merge: merge functions (null for unused counter type)
86 * @n_functions: number of instrumented functions
87 * @functions: pointer to pointers to function information
88 *
89 * This data is generated by gcc during compilation and doesn't change
90 * at run-time with the exception of the next pointer.
91 */
92 struct gcov_info {
93 unsigned int version;
94 struct gcov_info *next;
95 unsigned int stamp;
96 /* Since GCC 12.1 a checksum field is added. */
97 #if (__GNUC__ >= 12)
98 unsigned int checksum;
99 #endif
100 const char *filename;
101 void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int);
102 unsigned int n_functions;
103 struct gcov_fn_info **functions;
104 };
105
106 /**
107 * gcov_info_filename - return info filename
108 * @info: profiling data set
109 */
gcov_info_filename(struct gcov_info * info)110 const char *gcov_info_filename(struct gcov_info *info)
111 {
112 return info->filename;
113 }
114
115 /**
116 * gcov_info_version - return info version
117 * @info: profiling data set
118 */
gcov_info_version(struct gcov_info * info)119 unsigned int gcov_info_version(struct gcov_info *info)
120 {
121 return info->version;
122 }
123
124 /**
125 * gcov_info_next - return next profiling data set
126 * @info: profiling data set
127 *
128 * Returns next gcov_info following @info or first gcov_info in the chain if
129 * @info is %NULL.
130 */
gcov_info_next(struct gcov_info * info)131 struct gcov_info *gcov_info_next(struct gcov_info *info)
132 {
133 if (!info)
134 return gcov_info_head;
135
136 return info->next;
137 }
138
139 /**
140 * gcov_info_link - link/add profiling data set to the list
141 * @info: profiling data set
142 */
gcov_info_link(struct gcov_info * info)143 void gcov_info_link(struct gcov_info *info)
144 {
145 info->next = gcov_info_head;
146 gcov_info_head = info;
147 }
148
149 /**
150 * gcov_info_unlink - unlink/remove profiling data set from the list
151 * @prev: previous profiling data set
152 * @info: profiling data set
153 */
gcov_info_unlink(struct gcov_info * prev,struct gcov_info * info)154 void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
155 {
156 if (prev)
157 prev->next = info->next;
158 else
159 gcov_info_head = info->next;
160 }
161
162 /**
163 * gcov_info_within_module - check if a profiling data set belongs to a module
164 * @info: profiling data set
165 * @mod: module
166 *
167 * Returns true if profiling data belongs module, false otherwise.
168 */
gcov_info_within_module(struct gcov_info * info,struct module * mod)169 bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
170 {
171 return within_module((unsigned long)info, mod);
172 }
173
174 /* Symbolic links to be created for each profiling data file. */
175 const struct gcov_link gcov_link[] = {
176 { OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
177 { 0, NULL},
178 };
179
180 /*
181 * Determine whether a counter is active. Doesn't change at run-time.
182 */
counter_active(struct gcov_info * info,unsigned int type)183 static int counter_active(struct gcov_info *info, unsigned int type)
184 {
185 return info->merge[type] ? 1 : 0;
186 }
187
188 /* Determine number of active counters. Based on gcc magic. */
num_counter_active(struct gcov_info * info)189 static unsigned int num_counter_active(struct gcov_info *info)
190 {
191 unsigned int i;
192 unsigned int result = 0;
193
194 for (i = 0; i < GCOV_COUNTERS; i++) {
195 if (counter_active(info, i))
196 result++;
197 }
198 return result;
199 }
200
201 /**
202 * gcov_info_reset - reset profiling data to zero
203 * @info: profiling data set
204 */
gcov_info_reset(struct gcov_info * info)205 void gcov_info_reset(struct gcov_info *info)
206 {
207 struct gcov_ctr_info *ci_ptr;
208 unsigned int fi_idx;
209 unsigned int ct_idx;
210
211 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
212 ci_ptr = info->functions[fi_idx]->ctrs;
213
214 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
215 if (!counter_active(info, ct_idx))
216 continue;
217
218 memset(ci_ptr->values, 0,
219 sizeof(gcov_type) * ci_ptr->num);
220 ci_ptr++;
221 }
222 }
223 }
224
225 /**
226 * gcov_info_is_compatible - check if profiling data can be added
227 * @info1: first profiling data set
228 * @info2: second profiling data set
229 *
230 * Returns non-zero if profiling data can be added, zero otherwise.
231 */
gcov_info_is_compatible(struct gcov_info * info1,struct gcov_info * info2)232 int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
233 {
234 return (info1->stamp == info2->stamp);
235 }
236
237 /**
238 * gcov_info_add - add up profiling data
239 * @dst: profiling data set to which data is added
240 * @src: profiling data set which is added
241 *
242 * Adds profiling counts of @src to @dst.
243 */
gcov_info_add(struct gcov_info * dst,struct gcov_info * src)244 void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
245 {
246 struct gcov_ctr_info *dci_ptr;
247 struct gcov_ctr_info *sci_ptr;
248 unsigned int fi_idx;
249 unsigned int ct_idx;
250 unsigned int val_idx;
251
252 for (fi_idx = 0; fi_idx < src->n_functions; fi_idx++) {
253 dci_ptr = dst->functions[fi_idx]->ctrs;
254 sci_ptr = src->functions[fi_idx]->ctrs;
255
256 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
257 if (!counter_active(src, ct_idx))
258 continue;
259
260 for (val_idx = 0; val_idx < sci_ptr->num; val_idx++)
261 dci_ptr->values[val_idx] +=
262 sci_ptr->values[val_idx];
263
264 dci_ptr++;
265 sci_ptr++;
266 }
267 }
268 }
269
270 /**
271 * gcov_info_dup - duplicate profiling data set
272 * @info: profiling data set to duplicate
273 *
274 * Return newly allocated duplicate on success, %NULL on error.
275 */
gcov_info_dup(struct gcov_info * info)276 struct gcov_info *gcov_info_dup(struct gcov_info *info)
277 {
278 struct gcov_info *dup;
279 struct gcov_ctr_info *dci_ptr; /* dst counter info */
280 struct gcov_ctr_info *sci_ptr; /* src counter info */
281 unsigned int active;
282 unsigned int fi_idx; /* function info idx */
283 unsigned int ct_idx; /* counter type idx */
284 size_t fi_size; /* function info size */
285 size_t cv_size; /* counter values size */
286
287 dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
288 if (!dup)
289 return NULL;
290
291 dup->next = NULL;
292 dup->filename = NULL;
293 dup->functions = NULL;
294
295 dup->filename = kstrdup(info->filename, GFP_KERNEL);
296 if (!dup->filename)
297 goto err_free;
298
299 dup->functions = kcalloc(info->n_functions,
300 sizeof(struct gcov_fn_info *), GFP_KERNEL);
301 if (!dup->functions)
302 goto err_free;
303
304 active = num_counter_active(info);
305 fi_size = sizeof(struct gcov_fn_info);
306 fi_size += sizeof(struct gcov_ctr_info) * active;
307
308 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
309 dup->functions[fi_idx] = kzalloc(fi_size, GFP_KERNEL);
310 if (!dup->functions[fi_idx])
311 goto err_free;
312
313 *(dup->functions[fi_idx]) = *(info->functions[fi_idx]);
314
315 sci_ptr = info->functions[fi_idx]->ctrs;
316 dci_ptr = dup->functions[fi_idx]->ctrs;
317
318 for (ct_idx = 0; ct_idx < active; ct_idx++) {
319
320 cv_size = sizeof(gcov_type) * sci_ptr->num;
321
322 dci_ptr->values = kvmalloc(cv_size, GFP_KERNEL);
323
324 if (!dci_ptr->values)
325 goto err_free;
326
327 dci_ptr->num = sci_ptr->num;
328 memcpy(dci_ptr->values, sci_ptr->values, cv_size);
329
330 sci_ptr++;
331 dci_ptr++;
332 }
333 }
334
335 return dup;
336 err_free:
337 gcov_info_free(dup);
338 return NULL;
339 }
340
341 /**
342 * gcov_info_free - release memory for profiling data set duplicate
343 * @info: profiling data set duplicate to free
344 */
gcov_info_free(struct gcov_info * info)345 void gcov_info_free(struct gcov_info *info)
346 {
347 unsigned int active;
348 unsigned int fi_idx;
349 unsigned int ct_idx;
350 struct gcov_ctr_info *ci_ptr;
351
352 if (!info->functions)
353 goto free_info;
354
355 active = num_counter_active(info);
356
357 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
358 if (!info->functions[fi_idx])
359 continue;
360
361 ci_ptr = info->functions[fi_idx]->ctrs;
362
363 for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++)
364 kvfree(ci_ptr->values);
365
366 kfree(info->functions[fi_idx]);
367 }
368
369 free_info:
370 kfree(info->functions);
371 kfree(info->filename);
372 kfree(info);
373 }
374
375 /**
376 * convert_to_gcda - convert profiling data set to gcda file format
377 * @buffer: the buffer to store file data or %NULL if no data should be stored
378 * @info: profiling data set to be converted
379 *
380 * Returns the number of bytes that were/would have been stored into the buffer.
381 */
convert_to_gcda(char * buffer,struct gcov_info * info)382 size_t convert_to_gcda(char *buffer, struct gcov_info *info)
383 {
384 struct gcov_fn_info *fi_ptr;
385 struct gcov_ctr_info *ci_ptr;
386 unsigned int fi_idx;
387 unsigned int ct_idx;
388 unsigned int cv_idx;
389 size_t pos = 0;
390
391 /* File header. */
392 pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
393 pos += store_gcov_u32(buffer, pos, info->version);
394 pos += store_gcov_u32(buffer, pos, info->stamp);
395
396 #if (__GNUC__ >= 12)
397 /* Use zero as checksum of the compilation unit. */
398 pos += store_gcov_u32(buffer, pos, 0);
399 #endif
400
401 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
402 fi_ptr = info->functions[fi_idx];
403
404 /* Function record. */
405 pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
406 pos += store_gcov_u32(buffer, pos,
407 GCOV_TAG_FUNCTION_LENGTH * GCOV_UNIT_SIZE);
408 pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
409 pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum);
410 pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
411
412 ci_ptr = fi_ptr->ctrs;
413
414 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
415 if (!counter_active(info, ct_idx))
416 continue;
417
418 /* Counter record. */
419 pos += store_gcov_u32(buffer, pos,
420 GCOV_TAG_FOR_COUNTER(ct_idx));
421 pos += store_gcov_u32(buffer, pos,
422 ci_ptr->num * 2 * GCOV_UNIT_SIZE);
423
424 for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
425 pos += store_gcov_u64(buffer, pos,
426 ci_ptr->values[cv_idx]);
427 }
428
429 ci_ptr++;
430 }
431 }
432
433 return pos;
434 }
435