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