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 40 static 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 */ 50 struct 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 */ 72 struct 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 */ 94 struct 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 */ 112 const 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 */ 121 unsigned 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 */ 133 struct 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 */ 145 void 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 */ 156 void 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 */ 171 bool gcov_info_within_module(struct gcov_info *info, struct module *mod) 172 { 173 return within_module((unsigned long)info, mod); 174 } 175 176 /* 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). */ 179 { 0, NULL}, 180 }; 181 182 /* 183 * Determine whether a counter is active. Doesn't change at run-time. 184 */ 185 static 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. */ 191 static 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, 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 */ 207 void 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, 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 */ 234 int 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 */ 246 void 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(src, 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 */ 278 struct 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(info, 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(info->filename, GFP_KERNEL); 298 if (!dup->filename) 299 goto err_free; 300 301 dup->functions = kcalloc(info->n_functions, 302 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(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(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; 338 err_free: 339 gcov_info_free(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 */ 347 void 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(ci_ptr->values); 367 368 kfree(info->functions[fi_idx]); 369 } 370 371 free_info: 372 kfree(info->functions); 373 kfree(info->filename); 374 kfree(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 */ 384 size_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, pos, GCOV_DATA_MAGIC); 395 pos += store_gcov_u32(buffer, pos, info->version); 396 pos += store_gcov_u32(buffer, pos, 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, 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); 413 414 ci_ptr = fi_ptr->ctrs; 415 416 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) { 417 if (!counter_active(info, ct_idx)) 418 continue; 419 420 /* 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); 425 426 for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) { 427 pos += store_gcov_u64(buffer, pos, 428 ci_ptr->values[cv_idx]); 429 } 430 431 ci_ptr++; 432 } 433 } 434 435 return pos; 436 } 437