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 #elif (__GNUC__ >= 7)
26 #define GCOV_COUNTERS 9
27 #elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)
28 #define GCOV_COUNTERS 10
29 #else
30 #define GCOV_COUNTERS 9
31 #endif
32
33 #define GCOV_TAG_FUNCTION_LENGTH 3
34
35 /* Since GCC 12.1 sizes are in BYTES and not in WORDS (4B). */
36 #if (__GNUC__ >= 12)
37 #define GCOV_UNIT_SIZE 4
38 #else
39 #define GCOV_UNIT_SIZE 1
40 #endif
41
42 static struct gcov_info *gcov_info_head;
43
44 /**
45 * struct gcov_ctr_info - information about counters for a single function
46 * @num: number of counter values for this type
47 * @values: array of counter values for this type
48 *
49 * This data is generated by gcc during compilation and doesn't change
50 * at run-time with the exception of the values array.
51 */
52 struct gcov_ctr_info {
53 unsigned int num;
54 gcov_type *values;
55 };
56
57 /**
58 * struct gcov_fn_info - profiling meta data per function
59 * @key: comdat key
60 * @ident: unique ident of function
61 * @lineno_checksum: function lineo_checksum
62 * @cfg_checksum: function cfg checksum
63 * @ctrs: instrumented counters
64 *
65 * This data is generated by gcc during compilation and doesn't change
66 * at run-time.
67 *
68 * Information about a single function. This uses the trailing array
69 * idiom. The number of counters is determined from the merge pointer
70 * array in gcov_info. The key is used to detect which of a set of
71 * comdat functions was selected -- it points to the gcov_info object
72 * of the object file containing the selected comdat function.
73 */
74 struct gcov_fn_info {
75 const struct gcov_info *key;
76 unsigned int ident;
77 unsigned int lineno_checksum;
78 unsigned int cfg_checksum;
79 struct gcov_ctr_info ctrs[];
80 };
81
82 /**
83 * struct gcov_info - profiling data per object file
84 * @version: gcov version magic indicating the gcc version used for compilation
85 * @next: list head for a singly-linked list
86 * @stamp: uniquifying time stamp
87 * @checksum: unique object checksum
88 * @filename: name of the associated gcov data file
89 * @merge: merge functions (null for unused counter type)
90 * @n_functions: number of instrumented functions
91 * @functions: pointer to pointers to function information
92 *
93 * This data is generated by gcc during compilation and doesn't change
94 * at run-time with the exception of the next pointer.
95 */
96 struct gcov_info {
97 unsigned int version;
98 struct gcov_info *next;
99 unsigned int stamp;
100 /* Since GCC 12.1 a checksum field is added. */
101 #if (__GNUC__ >= 12)
102 unsigned int checksum;
103 #endif
104 const char *filename;
105 void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int);
106 unsigned int n_functions;
107 struct gcov_fn_info **functions;
108 };
109
110 /**
111 * gcov_info_filename - return info filename
112 * @info: profiling data set
113 */
gcov_info_filename(struct gcov_info * info)114 const char *gcov_info_filename(struct gcov_info *info)
115 {
116 return info->filename;
117 }
118
119 /**
120 * gcov_info_version - return info version
121 * @info: profiling data set
122 */
gcov_info_version(struct gcov_info * info)123 unsigned int gcov_info_version(struct gcov_info *info)
124 {
125 return info->version;
126 }
127
128 /**
129 * gcov_info_next - return next profiling data set
130 * @info: profiling data set
131 *
132 * Returns next gcov_info following @info or first gcov_info in the chain if
133 * @info is %NULL.
134 */
gcov_info_next(struct gcov_info * info)135 struct gcov_info *gcov_info_next(struct gcov_info *info)
136 {
137 if (!info)
138 return gcov_info_head;
139
140 return info->next;
141 }
142
143 /**
144 * gcov_info_link - link/add profiling data set to the list
145 * @info: profiling data set
146 */
gcov_info_link(struct gcov_info * info)147 void gcov_info_link(struct gcov_info *info)
148 {
149 info->next = gcov_info_head;
150 gcov_info_head = info;
151 }
152
153 /**
154 * gcov_info_unlink - unlink/remove profiling data set from the list
155 * @prev: previous profiling data set
156 * @info: profiling data set
157 */
gcov_info_unlink(struct gcov_info * prev,struct gcov_info * info)158 void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
159 {
160 if (prev)
161 prev->next = info->next;
162 else
163 gcov_info_head = info->next;
164 }
165
166 /**
167 * gcov_info_within_module - check if a profiling data set belongs to a module
168 * @info: profiling data set
169 * @mod: module
170 *
171 * Returns true if profiling data belongs module, false otherwise.
172 */
gcov_info_within_module(struct gcov_info * info,struct module * mod)173 bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
174 {
175 return within_module((unsigned long)info, mod);
176 }
177
178 /* Symbolic links to be created for each profiling data file. */
179 const struct gcov_link gcov_link[] = {
180 { OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */
181 { 0, NULL},
182 };
183
184 /*
185 * Determine whether a counter is active. Doesn't change at run-time.
186 */
counter_active(struct gcov_info * info,unsigned int type)187 static int counter_active(struct gcov_info *info, unsigned int type)
188 {
189 return info->merge[type] ? 1 : 0;
190 }
191
192 /* Determine number of active counters. Based on gcc magic. */
num_counter_active(struct gcov_info * info)193 static unsigned int num_counter_active(struct gcov_info *info)
194 {
195 unsigned int i;
196 unsigned int result = 0;
197
198 for (i = 0; i < GCOV_COUNTERS; i++) {
199 if (counter_active(info, i))
200 result++;
201 }
202 return result;
203 }
204
205 /**
206 * gcov_info_reset - reset profiling data to zero
207 * @info: profiling data set
208 */
gcov_info_reset(struct gcov_info * info)209 void gcov_info_reset(struct gcov_info *info)
210 {
211 struct gcov_ctr_info *ci_ptr;
212 unsigned int fi_idx;
213 unsigned int ct_idx;
214
215 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
216 ci_ptr = info->functions[fi_idx]->ctrs;
217
218 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
219 if (!counter_active(info, ct_idx))
220 continue;
221
222 memset(ci_ptr->values, 0,
223 sizeof(gcov_type) * ci_ptr->num);
224 ci_ptr++;
225 }
226 }
227 }
228
229 /**
230 * gcov_info_is_compatible - check if profiling data can be added
231 * @info1: first profiling data set
232 * @info2: second profiling data set
233 *
234 * Returns non-zero if profiling data can be added, zero otherwise.
235 */
gcov_info_is_compatible(struct gcov_info * info1,struct gcov_info * info2)236 int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
237 {
238 return (info1->stamp == info2->stamp);
239 }
240
241 /**
242 * gcov_info_add - add up profiling data
243 * @dst: profiling data set to which data is added
244 * @src: profiling data set which is added
245 *
246 * Adds profiling counts of @src to @dst.
247 */
gcov_info_add(struct gcov_info * dst,struct gcov_info * src)248 void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
249 {
250 struct gcov_ctr_info *dci_ptr;
251 struct gcov_ctr_info *sci_ptr;
252 unsigned int fi_idx;
253 unsigned int ct_idx;
254 unsigned int val_idx;
255
256 for (fi_idx = 0; fi_idx < src->n_functions; fi_idx++) {
257 dci_ptr = dst->functions[fi_idx]->ctrs;
258 sci_ptr = src->functions[fi_idx]->ctrs;
259
260 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
261 if (!counter_active(src, ct_idx))
262 continue;
263
264 for (val_idx = 0; val_idx < sci_ptr->num; val_idx++)
265 dci_ptr->values[val_idx] +=
266 sci_ptr->values[val_idx];
267
268 dci_ptr++;
269 sci_ptr++;
270 }
271 }
272 }
273
274 /**
275 * gcov_info_dup - duplicate profiling data set
276 * @info: profiling data set to duplicate
277 *
278 * Return newly allocated duplicate on success, %NULL on error.
279 */
gcov_info_dup(struct gcov_info * info)280 struct gcov_info *gcov_info_dup(struct gcov_info *info)
281 {
282 struct gcov_info *dup;
283 struct gcov_ctr_info *dci_ptr; /* dst counter info */
284 struct gcov_ctr_info *sci_ptr; /* src counter info */
285 unsigned int active;
286 unsigned int fi_idx; /* function info idx */
287 unsigned int ct_idx; /* counter type idx */
288 size_t fi_size; /* function info size */
289 size_t cv_size; /* counter values size */
290
291 dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
292 if (!dup)
293 return NULL;
294
295 dup->next = NULL;
296 dup->filename = NULL;
297 dup->functions = NULL;
298
299 dup->filename = kstrdup(info->filename, GFP_KERNEL);
300 if (!dup->filename)
301 goto err_free;
302
303 dup->functions = kcalloc(info->n_functions,
304 sizeof(struct gcov_fn_info *), GFP_KERNEL);
305 if (!dup->functions)
306 goto err_free;
307
308 active = num_counter_active(info);
309 fi_size = sizeof(struct gcov_fn_info);
310 fi_size += sizeof(struct gcov_ctr_info) * active;
311
312 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
313 dup->functions[fi_idx] = kzalloc(fi_size, GFP_KERNEL);
314 if (!dup->functions[fi_idx])
315 goto err_free;
316
317 *(dup->functions[fi_idx]) = *(info->functions[fi_idx]);
318
319 sci_ptr = info->functions[fi_idx]->ctrs;
320 dci_ptr = dup->functions[fi_idx]->ctrs;
321
322 for (ct_idx = 0; ct_idx < active; ct_idx++) {
323
324 cv_size = sizeof(gcov_type) * sci_ptr->num;
325
326 dci_ptr->values = kvmalloc(cv_size, GFP_KERNEL);
327
328 if (!dci_ptr->values)
329 goto err_free;
330
331 dci_ptr->num = sci_ptr->num;
332 memcpy(dci_ptr->values, sci_ptr->values, cv_size);
333
334 sci_ptr++;
335 dci_ptr++;
336 }
337 }
338
339 return dup;
340 err_free:
341 gcov_info_free(dup);
342 return NULL;
343 }
344
345 /**
346 * gcov_info_free - release memory for profiling data set duplicate
347 * @info: profiling data set duplicate to free
348 */
gcov_info_free(struct gcov_info * info)349 void gcov_info_free(struct gcov_info *info)
350 {
351 unsigned int active;
352 unsigned int fi_idx;
353 unsigned int ct_idx;
354 struct gcov_ctr_info *ci_ptr;
355
356 if (!info->functions)
357 goto free_info;
358
359 active = num_counter_active(info);
360
361 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
362 if (!info->functions[fi_idx])
363 continue;
364
365 ci_ptr = info->functions[fi_idx]->ctrs;
366
367 for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++)
368 kvfree(ci_ptr->values);
369
370 kfree(info->functions[fi_idx]);
371 }
372
373 free_info:
374 kfree(info->functions);
375 kfree(info->filename);
376 kfree(info);
377 }
378
379 /**
380 * convert_to_gcda - convert profiling data set to gcda file format
381 * @buffer: the buffer to store file data or %NULL if no data should be stored
382 * @info: profiling data set to be converted
383 *
384 * Returns the number of bytes that were/would have been stored into the buffer.
385 */
convert_to_gcda(char * buffer,struct gcov_info * info)386 size_t convert_to_gcda(char *buffer, struct gcov_info *info)
387 {
388 struct gcov_fn_info *fi_ptr;
389 struct gcov_ctr_info *ci_ptr;
390 unsigned int fi_idx;
391 unsigned int ct_idx;
392 unsigned int cv_idx;
393 size_t pos = 0;
394
395 /* File header. */
396 pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
397 pos += store_gcov_u32(buffer, pos, info->version);
398 pos += store_gcov_u32(buffer, pos, info->stamp);
399
400 #if (__GNUC__ >= 12)
401 /* Use zero as checksum of the compilation unit. */
402 pos += store_gcov_u32(buffer, pos, 0);
403 #endif
404
405 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
406 fi_ptr = info->functions[fi_idx];
407
408 /* Function record. */
409 pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
410 pos += store_gcov_u32(buffer, pos,
411 GCOV_TAG_FUNCTION_LENGTH * GCOV_UNIT_SIZE);
412 pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
413 pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum);
414 pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
415
416 ci_ptr = fi_ptr->ctrs;
417
418 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
419 if (!counter_active(info, ct_idx))
420 continue;
421
422 /* Counter record. */
423 pos += store_gcov_u32(buffer, pos,
424 GCOV_TAG_FOR_COUNTER(ct_idx));
425 pos += store_gcov_u32(buffer, pos,
426 ci_ptr->num * 2 * GCOV_UNIT_SIZE);
427
428 for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
429 pos += store_gcov_u64(buffer, pos,
430 ci_ptr->values[cv_idx]);
431 }
432
433 ci_ptr++;
434 }
435 }
436
437 return pos;
438 }
439