1/* 2 * This code provides functions to handle gcc's profiling data format 3 * introduced with gcc 4.7. 4 * 5 * This file is based heavily on gcc_3_4.c file. 6 * 7 * For a better understanding, refer to gcc source: 8 * gcc/gcov-io.h 9 * libgcc/libgcov.c 10 * 11 * Uses gcc-internal data definitions. 12 */ 13 14#include <linux/errno.h> 15#include <linux/slab.h> 16#include <linux/string.h> 17#include <linux/seq_file.h> 18#include <linux/vmalloc.h> 19#include "gcov.h" 20 21#if __GNUC__ == 5 && __GNUC_MINOR__ >= 1 22#define GCOV_COUNTERS 10 23#elif __GNUC__ == 4 && __GNUC_MINOR__ >= 9 24#define GCOV_COUNTERS 9 25#else 26#define GCOV_COUNTERS 8 27#endif 28 29#define GCOV_TAG_FUNCTION_LENGTH 3 30 31static struct gcov_info *gcov_info_head; 32 33/** 34 * struct gcov_ctr_info - information about counters for a single function 35 * @num: number of counter values for this type 36 * @values: array of counter values for this type 37 * 38 * This data is generated by gcc during compilation and doesn't change 39 * at run-time with the exception of the values array. 40 */ 41struct gcov_ctr_info { 42 unsigned int num; 43 gcov_type *values; 44}; 45 46/** 47 * struct gcov_fn_info - profiling meta data per function 48 * @key: comdat key 49 * @ident: unique ident of function 50 * @lineno_checksum: function lineo_checksum 51 * @cfg_checksum: function cfg checksum 52 * @ctrs: instrumented counters 53 * 54 * This data is generated by gcc during compilation and doesn't change 55 * at run-time. 56 * 57 * Information about a single function. This uses the trailing array 58 * idiom. The number of counters is determined from the merge pointer 59 * array in gcov_info. The key is used to detect which of a set of 60 * comdat functions was selected -- it points to the gcov_info object 61 * of the object file containing the selected comdat function. 62 */ 63struct gcov_fn_info { 64 const struct gcov_info *key; 65 unsigned int ident; 66 unsigned int lineno_checksum; 67 unsigned int cfg_checksum; 68 struct gcov_ctr_info ctrs[0]; 69}; 70 71/** 72 * struct gcov_info - profiling data per object file 73 * @version: gcov version magic indicating the gcc version used for compilation 74 * @next: list head for a singly-linked list 75 * @stamp: uniquifying time stamp 76 * @filename: name of the associated gcov data file 77 * @merge: merge functions (null for unused counter type) 78 * @n_functions: number of instrumented functions 79 * @functions: pointer to pointers to function information 80 * 81 * This data is generated by gcc during compilation and doesn't change 82 * at run-time with the exception of the next pointer. 83 */ 84struct gcov_info { 85 unsigned int version; 86 struct gcov_info *next; 87 unsigned int stamp; 88 const char *filename; 89 void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int); 90 unsigned int n_functions; 91 struct gcov_fn_info **functions; 92}; 93 94/** 95 * gcov_info_filename - return info filename 96 * @info: profiling data set 97 */ 98const char *gcov_info_filename(struct gcov_info *info) 99{ 100 return info->filename; 101} 102 103/** 104 * gcov_info_version - return info version 105 * @info: profiling data set 106 */ 107unsigned int gcov_info_version(struct gcov_info *info) 108{ 109 return info->version; 110} 111 112/** 113 * gcov_info_next - return next profiling data set 114 * @info: profiling data set 115 * 116 * Returns next gcov_info following @info or first gcov_info in the chain if 117 * @info is %NULL. 118 */ 119struct gcov_info *gcov_info_next(struct gcov_info *info) 120{ 121 if (!info) 122 return gcov_info_head; 123 124 return info->next; 125} 126 127/** 128 * gcov_info_link - link/add profiling data set to the list 129 * @info: profiling data set 130 */ 131void gcov_info_link(struct gcov_info *info) 132{ 133 info->next = gcov_info_head; 134 gcov_info_head = info; 135} 136 137/** 138 * gcov_info_unlink - unlink/remove profiling data set from the list 139 * @prev: previous profiling data set 140 * @info: profiling data set 141 */ 142void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info) 143{ 144 if (prev) 145 prev->next = info->next; 146 else 147 gcov_info_head = info->next; 148} 149 150/* Symbolic links to be created for each profiling data file. */ 151const struct gcov_link gcov_link[] = { 152 { OBJ_TREE, "gcno" }, /* Link to .gcno file in $(objtree). */ 153 { 0, NULL}, 154}; 155 156/* 157 * Determine whether a counter is active. Doesn't change at run-time. 158 */ 159static int counter_active(struct gcov_info *info, unsigned int type) 160{ 161 return info->merge[type] ? 1 : 0; 162} 163 164/* Determine number of active counters. Based on gcc magic. */ 165static unsigned int num_counter_active(struct gcov_info *info) 166{ 167 unsigned int i; 168 unsigned int result = 0; 169 170 for (i = 0; i < GCOV_COUNTERS; i++) { 171 if (counter_active(info, i)) 172 result++; 173 } 174 return result; 175} 176 177/** 178 * gcov_info_reset - reset profiling data to zero 179 * @info: profiling data set 180 */ 181void gcov_info_reset(struct gcov_info *info) 182{ 183 struct gcov_ctr_info *ci_ptr; 184 unsigned int fi_idx; 185 unsigned int ct_idx; 186 187 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) { 188 ci_ptr = info->functions[fi_idx]->ctrs; 189 190 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) { 191 if (!counter_active(info, ct_idx)) 192 continue; 193 194 memset(ci_ptr->values, 0, 195 sizeof(gcov_type) * ci_ptr->num); 196 ci_ptr++; 197 } 198 } 199} 200 201/** 202 * gcov_info_is_compatible - check if profiling data can be added 203 * @info1: first profiling data set 204 * @info2: second profiling data set 205 * 206 * Returns non-zero if profiling data can be added, zero otherwise. 207 */ 208int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2) 209{ 210 return (info1->stamp == info2->stamp); 211} 212 213/** 214 * gcov_info_add - add up profiling data 215 * @dest: profiling data set to which data is added 216 * @source: profiling data set which is added 217 * 218 * Adds profiling counts of @source to @dest. 219 */ 220void gcov_info_add(struct gcov_info *dst, struct gcov_info *src) 221{ 222 struct gcov_ctr_info *dci_ptr; 223 struct gcov_ctr_info *sci_ptr; 224 unsigned int fi_idx; 225 unsigned int ct_idx; 226 unsigned int val_idx; 227 228 for (fi_idx = 0; fi_idx < src->n_functions; fi_idx++) { 229 dci_ptr = dst->functions[fi_idx]->ctrs; 230 sci_ptr = src->functions[fi_idx]->ctrs; 231 232 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) { 233 if (!counter_active(src, ct_idx)) 234 continue; 235 236 for (val_idx = 0; val_idx < sci_ptr->num; val_idx++) 237 dci_ptr->values[val_idx] += 238 sci_ptr->values[val_idx]; 239 240 dci_ptr++; 241 sci_ptr++; 242 } 243 } 244} 245 246/** 247 * gcov_info_dup - duplicate profiling data set 248 * @info: profiling data set to duplicate 249 * 250 * Return newly allocated duplicate on success, %NULL on error. 251 */ 252struct gcov_info *gcov_info_dup(struct gcov_info *info) 253{ 254 struct gcov_info *dup; 255 struct gcov_ctr_info *dci_ptr; /* dst counter info */ 256 struct gcov_ctr_info *sci_ptr; /* src counter info */ 257 unsigned int active; 258 unsigned int fi_idx; /* function info idx */ 259 unsigned int ct_idx; /* counter type idx */ 260 size_t fi_size; /* function info size */ 261 size_t cv_size; /* counter values size */ 262 263 dup = kmemdup(info, sizeof(*dup), GFP_KERNEL); 264 if (!dup) 265 return NULL; 266 267 dup->next = NULL; 268 dup->filename = NULL; 269 dup->functions = NULL; 270 271 dup->filename = kstrdup(info->filename, GFP_KERNEL); 272 if (!dup->filename) 273 goto err_free; 274 275 dup->functions = kcalloc(info->n_functions, 276 sizeof(struct gcov_fn_info *), GFP_KERNEL); 277 if (!dup->functions) 278 goto err_free; 279 280 active = num_counter_active(info); 281 fi_size = sizeof(struct gcov_fn_info); 282 fi_size += sizeof(struct gcov_ctr_info) * active; 283 284 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) { 285 dup->functions[fi_idx] = kzalloc(fi_size, GFP_KERNEL); 286 if (!dup->functions[fi_idx]) 287 goto err_free; 288 289 *(dup->functions[fi_idx]) = *(info->functions[fi_idx]); 290 291 sci_ptr = info->functions[fi_idx]->ctrs; 292 dci_ptr = dup->functions[fi_idx]->ctrs; 293 294 for (ct_idx = 0; ct_idx < active; ct_idx++) { 295 296 cv_size = sizeof(gcov_type) * sci_ptr->num; 297 298 dci_ptr->values = vmalloc(cv_size); 299 300 if (!dci_ptr->values) 301 goto err_free; 302 303 dci_ptr->num = sci_ptr->num; 304 memcpy(dci_ptr->values, sci_ptr->values, cv_size); 305 306 sci_ptr++; 307 dci_ptr++; 308 } 309 } 310 311 return dup; 312err_free: 313 gcov_info_free(dup); 314 return NULL; 315} 316 317/** 318 * gcov_info_free - release memory for profiling data set duplicate 319 * @info: profiling data set duplicate to free 320 */ 321void gcov_info_free(struct gcov_info *info) 322{ 323 unsigned int active; 324 unsigned int fi_idx; 325 unsigned int ct_idx; 326 struct gcov_ctr_info *ci_ptr; 327 328 if (!info->functions) 329 goto free_info; 330 331 active = num_counter_active(info); 332 333 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) { 334 if (!info->functions[fi_idx]) 335 continue; 336 337 ci_ptr = info->functions[fi_idx]->ctrs; 338 339 for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++) 340 vfree(ci_ptr->values); 341 342 kfree(info->functions[fi_idx]); 343 } 344 345free_info: 346 kfree(info->functions); 347 kfree(info->filename); 348 kfree(info); 349} 350 351#define ITER_STRIDE PAGE_SIZE 352 353/** 354 * struct gcov_iterator - specifies current file position in logical records 355 * @info: associated profiling data 356 * @buffer: buffer containing file data 357 * @size: size of buffer 358 * @pos: current position in file 359 */ 360struct gcov_iterator { 361 struct gcov_info *info; 362 void *buffer; 363 size_t size; 364 loff_t pos; 365}; 366 367/** 368 * store_gcov_u32 - store 32 bit number in gcov format to buffer 369 * @buffer: target buffer or NULL 370 * @off: offset into the buffer 371 * @v: value to be stored 372 * 373 * Number format defined by gcc: numbers are recorded in the 32 bit 374 * unsigned binary form of the endianness of the machine generating the 375 * file. Returns the number of bytes stored. If @buffer is %NULL, doesn't 376 * store anything. 377 */ 378static size_t store_gcov_u32(void *buffer, size_t off, u32 v) 379{ 380 u32 *data; 381 382 if (buffer) { 383 data = buffer + off; 384 *data = v; 385 } 386 387 return sizeof(*data); 388} 389 390/** 391 * store_gcov_u64 - store 64 bit number in gcov format to buffer 392 * @buffer: target buffer or NULL 393 * @off: offset into the buffer 394 * @v: value to be stored 395 * 396 * Number format defined by gcc: numbers are recorded in the 32 bit 397 * unsigned binary form of the endianness of the machine generating the 398 * file. 64 bit numbers are stored as two 32 bit numbers, the low part 399 * first. Returns the number of bytes stored. If @buffer is %NULL, doesn't store 400 * anything. 401 */ 402static size_t store_gcov_u64(void *buffer, size_t off, u64 v) 403{ 404 u32 *data; 405 406 if (buffer) { 407 data = buffer + off; 408 409 data[0] = (v & 0xffffffffUL); 410 data[1] = (v >> 32); 411 } 412 413 return sizeof(*data) * 2; 414} 415 416/** 417 * convert_to_gcda - convert profiling data set to gcda file format 418 * @buffer: the buffer to store file data or %NULL if no data should be stored 419 * @info: profiling data set to be converted 420 * 421 * Returns the number of bytes that were/would have been stored into the buffer. 422 */ 423static size_t convert_to_gcda(char *buffer, struct gcov_info *info) 424{ 425 struct gcov_fn_info *fi_ptr; 426 struct gcov_ctr_info *ci_ptr; 427 unsigned int fi_idx; 428 unsigned int ct_idx; 429 unsigned int cv_idx; 430 size_t pos = 0; 431 432 /* File header. */ 433 pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC); 434 pos += store_gcov_u32(buffer, pos, info->version); 435 pos += store_gcov_u32(buffer, pos, info->stamp); 436 437 for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) { 438 fi_ptr = info->functions[fi_idx]; 439 440 /* Function record. */ 441 pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION); 442 pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION_LENGTH); 443 pos += store_gcov_u32(buffer, pos, fi_ptr->ident); 444 pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum); 445 pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum); 446 447 ci_ptr = fi_ptr->ctrs; 448 449 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) { 450 if (!counter_active(info, ct_idx)) 451 continue; 452 453 /* Counter record. */ 454 pos += store_gcov_u32(buffer, pos, 455 GCOV_TAG_FOR_COUNTER(ct_idx)); 456 pos += store_gcov_u32(buffer, pos, ci_ptr->num * 2); 457 458 for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) { 459 pos += store_gcov_u64(buffer, pos, 460 ci_ptr->values[cv_idx]); 461 } 462 463 ci_ptr++; 464 } 465 } 466 467 return pos; 468} 469 470/** 471 * gcov_iter_new - allocate and initialize profiling data iterator 472 * @info: profiling data set to be iterated 473 * 474 * Return file iterator on success, %NULL otherwise. 475 */ 476struct gcov_iterator *gcov_iter_new(struct gcov_info *info) 477{ 478 struct gcov_iterator *iter; 479 480 iter = kzalloc(sizeof(struct gcov_iterator), GFP_KERNEL); 481 if (!iter) 482 goto err_free; 483 484 iter->info = info; 485 /* Dry-run to get the actual buffer size. */ 486 iter->size = convert_to_gcda(NULL, info); 487 iter->buffer = vmalloc(iter->size); 488 if (!iter->buffer) 489 goto err_free; 490 491 convert_to_gcda(iter->buffer, info); 492 493 return iter; 494 495err_free: 496 kfree(iter); 497 return NULL; 498} 499 500 501/** 502 * gcov_iter_get_info - return profiling data set for given file iterator 503 * @iter: file iterator 504 */ 505void gcov_iter_free(struct gcov_iterator *iter) 506{ 507 vfree(iter->buffer); 508 kfree(iter); 509} 510 511/** 512 * gcov_iter_get_info - return profiling data set for given file iterator 513 * @iter: file iterator 514 */ 515struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter) 516{ 517 return iter->info; 518} 519 520/** 521 * gcov_iter_start - reset file iterator to starting position 522 * @iter: file iterator 523 */ 524void gcov_iter_start(struct gcov_iterator *iter) 525{ 526 iter->pos = 0; 527} 528 529/** 530 * gcov_iter_next - advance file iterator to next logical record 531 * @iter: file iterator 532 * 533 * Return zero if new position is valid, non-zero if iterator has reached end. 534 */ 535int gcov_iter_next(struct gcov_iterator *iter) 536{ 537 if (iter->pos < iter->size) 538 iter->pos += ITER_STRIDE; 539 540 if (iter->pos >= iter->size) 541 return -EINVAL; 542 543 return 0; 544} 545 546/** 547 * gcov_iter_write - write data for current pos to seq_file 548 * @iter: file iterator 549 * @seq: seq_file handle 550 * 551 * Return zero on success, non-zero otherwise. 552 */ 553int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq) 554{ 555 size_t len; 556 557 if (iter->pos >= iter->size) 558 return -EINVAL; 559 560 len = ITER_STRIDE; 561 if (iter->pos + len > iter->size) 562 len = iter->size - iter->pos; 563 564 seq_write(seq, iter->buffer + iter->pos, len); 565 566 return 0; 567} 568