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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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. */ 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 */ 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 */ 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 */ 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 */ 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 */ 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 */ 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