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