root/kernel/gcov/gcc_4_7.c

DEFINITIONS

1. gcov_info_filename
2. gcov_info_version
3. gcov_info_next
4. gcov_info_link
5. gcov_info_unlink
6. gcov_info_within_module
7. counter_active
8. num_counter_active
9. gcov_info_reset
10. gcov_info_is_compatible
11. gcov_info_add
12. gcov_info_dup
13. gcov_info_free
14. store_gcov_u32
15. store_gcov_u64
16. convert_to_gcda
17. gcov_iter_new
18. gcov_iter_free
19. gcov_iter_get_info
20. gcov_iter_start
21. gcov_iter_next
22. gcov_iter_write

   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/seq_file.h>
  19 #include <linux/vmalloc.h>
  20 #include "gcov.h"
  21 
  22 #if (__GNUC__ >= 7)
  23 #define GCOV_COUNTERS                   9
  24 #elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)
  25 #define GCOV_COUNTERS                   10
  26 #elif __GNUC__ == 4 && __GNUC_MINOR__ >= 9
  27 #define GCOV_COUNTERS                   9
  28 #else
  29 #define GCOV_COUNTERS                   8
  30 #endif
  31 
  32 #define GCOV_TAG_FUNCTION_LENGTH        3
  33 
  34 static struct gcov_info *gcov_info_head;
  35 
  36 /**
  37  * struct gcov_ctr_info - information about counters for a single function
  38  * @num: number of counter values for this type
  39  * @values: array of counter values for this type
  40  *
  41  * This data is generated by gcc during compilation and doesn't change
  42  * at run-time with the exception of the values array.
  43  */
  44 struct gcov_ctr_info {
  45         unsigned int num;
  46         gcov_type *values;
  47 };
  48 
  49 /**
  50  * struct gcov_fn_info - profiling meta data per function
  51  * @key: comdat key
  52  * @ident: unique ident of function
  53  * @lineno_checksum: function lineo_checksum
  54  * @cfg_checksum: function cfg checksum
  55  * @ctrs: instrumented counters
  56  *
  57  * This data is generated by gcc during compilation and doesn't change
  58  * at run-time.
  59  *
  60  * Information about a single function.  This uses the trailing array
  61  * idiom. The number of counters is determined from the merge pointer
  62  * array in gcov_info.  The key is used to detect which of a set of
  63  * comdat functions was selected -- it points to the gcov_info object
  64  * of the object file containing the selected comdat function.
  65  */
  66 struct gcov_fn_info {
  67         const struct gcov_info *key;
  68         unsigned int ident;
  69         unsigned int lineno_checksum;
  70         unsigned int cfg_checksum;
  71         struct gcov_ctr_info ctrs[0];
  72 };
  73 
  74 /**
  75  * struct gcov_info - profiling data per object file
  76  * @version: gcov version magic indicating the gcc version used for compilation
  77  * @next: list head for a singly-linked list
  78  * @stamp: uniquifying time stamp
  79  * @filename: name of the associated gcov data file
  80  * @merge: merge functions (null for unused counter type)
  81  * @n_functions: number of instrumented functions
  82  * @functions: pointer to pointers to function information
  83  *
  84  * This data is generated by gcc during compilation and doesn't change
  85  * at run-time with the exception of the next pointer.
  86  */
  87 struct gcov_info {
  88         unsigned int version;
  89         struct gcov_info *next;
  90         unsigned int stamp;
  91         const char *filename;
  92         void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int);
  93         unsigned int n_functions;
  94         struct gcov_fn_info **functions;
  95 };
  96 
  97 /**
  98  * gcov_info_filename - return info filename
  99  * @info: profiling data set
 100  */
 101 const char *gcov_info_filename(struct gcov_info *info)
 102 {
 103         return info->filename;
 104 }
 105 
 106 /**
 107  * gcov_info_version - return info version
 108  * @info: profiling data set
 109  */
 110 unsigned int gcov_info_version(struct gcov_info *info)
 111 {
 112         return info->version;
 113 }
 114 
 115 /**
 116  * gcov_info_next - return next profiling data set
 117  * @info: profiling data set
 118  *
 119  * Returns next gcov_info following @info or first gcov_info in the chain if
 120  * @info is %NULL.
 121  */
 122 struct gcov_info *gcov_info_next(struct gcov_info *info)
 123 {
 124         if (!info)
 125                 return gcov_info_head;
 126 
 127         return info->next;
 128 }
 129 
 130 /**
 131  * gcov_info_link - link/add profiling data set to the list
 132  * @info: profiling data set
 133  */
 134 void gcov_info_link(struct gcov_info *info)
 135 {
 136         info->next = gcov_info_head;
 137         gcov_info_head = info;
 138 }
 139 
 140 /**
 141  * gcov_info_unlink - unlink/remove profiling data set from the list
 142  * @prev: previous profiling data set
 143  * @info: profiling data set
 144  */
 145 void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
 146 {
 147         if (prev)
 148                 prev->next = info->next;
 149         else
 150                 gcov_info_head = info->next;
 151 }
 152 
 153 /**
 154  * gcov_info_within_module - check if a profiling data set belongs to a module
 155  * @info: profiling data set
 156  * @mod: module
 157  *
 158  * Returns true if profiling data belongs module, false otherwise.
 159  */
 160 bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
 161 {
 162         return within_module((unsigned long)info, mod);
 163 }
 164 
 165 /* Symbolic links to be created for each profiling data file. */
 166 const struct gcov_link gcov_link[] = {
 167         { OBJ_TREE, "gcno" },   /* Link to .gcno file in $(objtree). */
 168         { 0, NULL},
 169 };
 170 
 171 /*
 172  * Determine whether a counter is active. Doesn't change at run-time.
 173  */
 174 static int counter_active(struct gcov_info *info, unsigned int type)
 175 {
 176         return info->merge[type] ? 1 : 0;
 177 }
 178 
 179 /* Determine number of active counters. Based on gcc magic. */
 180 static unsigned int num_counter_active(struct gcov_info *info)
 181 {
 182         unsigned int i;
 183         unsigned int result = 0;
 184 
 185         for (i = 0; i < GCOV_COUNTERS; i++) {
 186                 if (counter_active(info, i))
 187                         result++;
 188         }
 189         return result;
 190 }
 191 
 192 /**
 193  * gcov_info_reset - reset profiling data to zero
 194  * @info: profiling data set
 195  */
 196 void gcov_info_reset(struct gcov_info *info)
 197 {
 198         struct gcov_ctr_info *ci_ptr;
 199         unsigned int fi_idx;
 200         unsigned int ct_idx;
 201 
 202         for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
 203                 ci_ptr = info->functions[fi_idx]->ctrs;
 204 
 205                 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
 206                         if (!counter_active(info, ct_idx))
 207                                 continue;
 208 
 209                         memset(ci_ptr->values, 0,
 210                                         sizeof(gcov_type) * ci_ptr->num);
 211                         ci_ptr++;
 212                 }
 213         }
 214 }
 215 
 216 /**
 217  * gcov_info_is_compatible - check if profiling data can be added
 218  * @info1: first profiling data set
 219  * @info2: second profiling data set
 220  *
 221  * Returns non-zero if profiling data can be added, zero otherwise.
 222  */
 223 int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
 224 {
 225         return (info1->stamp == info2->stamp);
 226 }
 227 
 228 /**
 229  * gcov_info_add - add up profiling data
 230  * @dest: profiling data set to which data is added
 231  * @source: profiling data set which is added
 232  *
 233  * Adds profiling counts of @source to @dest.
 234  */
 235 void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
 236 {
 237         struct gcov_ctr_info *dci_ptr;
 238         struct gcov_ctr_info *sci_ptr;
 239         unsigned int fi_idx;
 240         unsigned int ct_idx;
 241         unsigned int val_idx;
 242 
 243         for (fi_idx = 0; fi_idx < src->n_functions; fi_idx++) {
 244                 dci_ptr = dst->functions[fi_idx]->ctrs;
 245                 sci_ptr = src->functions[fi_idx]->ctrs;
 246 
 247                 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
 248                         if (!counter_active(src, ct_idx))
 249                                 continue;
 250 
 251                         for (val_idx = 0; val_idx < sci_ptr->num; val_idx++)
 252                                 dci_ptr->values[val_idx] +=
 253                                         sci_ptr->values[val_idx];
 254 
 255                         dci_ptr++;
 256                         sci_ptr++;
 257                 }
 258         }
 259 }
 260 
 261 /**
 262  * gcov_info_dup - duplicate profiling data set
 263  * @info: profiling data set to duplicate
 264  *
 265  * Return newly allocated duplicate on success, %NULL on error.
 266  */
 267 struct gcov_info *gcov_info_dup(struct gcov_info *info)
 268 {
 269         struct gcov_info *dup;
 270         struct gcov_ctr_info *dci_ptr; /* dst counter info */
 271         struct gcov_ctr_info *sci_ptr; /* src counter info */
 272         unsigned int active;
 273         unsigned int fi_idx; /* function info idx */
 274         unsigned int ct_idx; /* counter type idx */
 275         size_t fi_size; /* function info size */
 276         size_t cv_size; /* counter values size */
 277 
 278         dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
 279         if (!dup)
 280                 return NULL;
 281 
 282         dup->next = NULL;
 283         dup->filename = NULL;
 284         dup->functions = NULL;
 285 
 286         dup->filename = kstrdup(info->filename, GFP_KERNEL);
 287         if (!dup->filename)
 288                 goto err_free;
 289 
 290         dup->functions = kcalloc(info->n_functions,
 291                                  sizeof(struct gcov_fn_info *), GFP_KERNEL);
 292         if (!dup->functions)
 293                 goto err_free;
 294 
 295         active = num_counter_active(info);
 296         fi_size = sizeof(struct gcov_fn_info);
 297         fi_size += sizeof(struct gcov_ctr_info) * active;
 298 
 299         for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
 300                 dup->functions[fi_idx] = kzalloc(fi_size, GFP_KERNEL);
 301                 if (!dup->functions[fi_idx])
 302                         goto err_free;
 303 
 304                 *(dup->functions[fi_idx]) = *(info->functions[fi_idx]);
 305 
 306                 sci_ptr = info->functions[fi_idx]->ctrs;
 307                 dci_ptr = dup->functions[fi_idx]->ctrs;
 308 
 309                 for (ct_idx = 0; ct_idx < active; ct_idx++) {
 310 
 311                         cv_size = sizeof(gcov_type) * sci_ptr->num;
 312 
 313                         dci_ptr->values = vmalloc(cv_size);
 314 
 315                         if (!dci_ptr->values)
 316                                 goto err_free;
 317 
 318                         dci_ptr->num = sci_ptr->num;
 319                         memcpy(dci_ptr->values, sci_ptr->values, cv_size);
 320 
 321                         sci_ptr++;
 322                         dci_ptr++;
 323                 }
 324         }
 325 
 326         return dup;
 327 err_free:
 328         gcov_info_free(dup);
 329         return NULL;
 330 }
 331 
 332 /**
 333  * gcov_info_free - release memory for profiling data set duplicate
 334  * @info: profiling data set duplicate to free
 335  */
 336 void gcov_info_free(struct gcov_info *info)
 337 {
 338         unsigned int active;
 339         unsigned int fi_idx;
 340         unsigned int ct_idx;
 341         struct gcov_ctr_info *ci_ptr;
 342 
 343         if (!info->functions)
 344                 goto free_info;
 345 
 346         active = num_counter_active(info);
 347 
 348         for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
 349                 if (!info->functions[fi_idx])
 350                         continue;
 351 
 352                 ci_ptr = info->functions[fi_idx]->ctrs;
 353 
 354                 for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++)
 355                         vfree(ci_ptr->values);
 356 
 357                 kfree(info->functions[fi_idx]);
 358         }
 359 
 360 free_info:
 361         kfree(info->functions);
 362         kfree(info->filename);
 363         kfree(info);
 364 }
 365 
 366 #define ITER_STRIDE     PAGE_SIZE
 367 
 368 /**
 369  * struct gcov_iterator - specifies current file position in logical records
 370  * @info: associated profiling data
 371  * @buffer: buffer containing file data
 372  * @size: size of buffer
 373  * @pos: current position in file
 374  */
 375 struct gcov_iterator {
 376         struct gcov_info *info;
 377         void *buffer;
 378         size_t size;
 379         loff_t pos;
 380 };
 381 
 382 /**
 383  * store_gcov_u32 - store 32 bit number in gcov format to buffer
 384  * @buffer: target buffer or NULL
 385  * @off: offset into the buffer
 386  * @v: value to be stored
 387  *
 388  * Number format defined by gcc: numbers are recorded in the 32 bit
 389  * unsigned binary form of the endianness of the machine generating the
 390  * file. Returns the number of bytes stored. If @buffer is %NULL, doesn't
 391  * store anything.
 392  */
 393 static size_t store_gcov_u32(void *buffer, size_t off, u32 v)
 394 {
 395         u32 *data;
 396 
 397         if (buffer) {
 398                 data = buffer + off;
 399                 *data = v;
 400         }
 401 
 402         return sizeof(*data);
 403 }
 404 
 405 /**
 406  * store_gcov_u64 - store 64 bit number in gcov format to buffer
 407  * @buffer: target buffer or NULL
 408  * @off: offset into the buffer
 409  * @v: value to be stored
 410  *
 411  * Number format defined by gcc: numbers are recorded in the 32 bit
 412  * unsigned binary form of the endianness of the machine generating the
 413  * file. 64 bit numbers are stored as two 32 bit numbers, the low part
 414  * first. Returns the number of bytes stored. If @buffer is %NULL, doesn't store
 415  * anything.
 416  */
 417 static size_t store_gcov_u64(void *buffer, size_t off, u64 v)
 418 {
 419         u32 *data;
 420 
 421         if (buffer) {
 422                 data = buffer + off;
 423 
 424                 data[0] = (v & 0xffffffffUL);
 425                 data[1] = (v >> 32);
 426         }
 427 
 428         return sizeof(*data) * 2;
 429 }
 430 
 431 /**
 432  * convert_to_gcda - convert profiling data set to gcda file format
 433  * @buffer: the buffer to store file data or %NULL if no data should be stored
 434  * @info: profiling data set to be converted
 435  *
 436  * Returns the number of bytes that were/would have been stored into the buffer.
 437  */
 438 static size_t convert_to_gcda(char *buffer, struct gcov_info *info)
 439 {
 440         struct gcov_fn_info *fi_ptr;
 441         struct gcov_ctr_info *ci_ptr;
 442         unsigned int fi_idx;
 443         unsigned int ct_idx;
 444         unsigned int cv_idx;
 445         size_t pos = 0;
 446 
 447         /* File header. */
 448         pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
 449         pos += store_gcov_u32(buffer, pos, info->version);
 450         pos += store_gcov_u32(buffer, pos, info->stamp);
 451 
 452         for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
 453                 fi_ptr = info->functions[fi_idx];
 454 
 455                 /* Function record. */
 456                 pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
 457                 pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION_LENGTH);
 458                 pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
 459                 pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum);
 460                 pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
 461 
 462                 ci_ptr = fi_ptr->ctrs;
 463 
 464                 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
 465                         if (!counter_active(info, ct_idx))
 466                                 continue;
 467 
 468                         /* Counter record. */
 469                         pos += store_gcov_u32(buffer, pos,
 470                                               GCOV_TAG_FOR_COUNTER(ct_idx));
 471                         pos += store_gcov_u32(buffer, pos, ci_ptr->num * 2);
 472 
 473                         for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
 474                                 pos += store_gcov_u64(buffer, pos,
 475                                                       ci_ptr->values[cv_idx]);
 476                         }
 477 
 478                         ci_ptr++;
 479                 }
 480         }
 481 
 482         return pos;
 483 }
 484 
 485 /**
 486  * gcov_iter_new - allocate and initialize profiling data iterator
 487  * @info: profiling data set to be iterated
 488  *
 489  * Return file iterator on success, %NULL otherwise.
 490  */
 491 struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
 492 {
 493         struct gcov_iterator *iter;
 494 
 495         iter = kzalloc(sizeof(struct gcov_iterator), GFP_KERNEL);
 496         if (!iter)
 497                 goto err_free;
 498 
 499         iter->info = info;
 500         /* Dry-run to get the actual buffer size. */
 501         iter->size = convert_to_gcda(NULL, info);
 502         iter->buffer = vmalloc(iter->size);
 503         if (!iter->buffer)
 504                 goto err_free;
 505 
 506         convert_to_gcda(iter->buffer, info);
 507 
 508         return iter;
 509 
 510 err_free:
 511         kfree(iter);
 512         return NULL;
 513 }
 514 
 515 
 516 /**
 517  * gcov_iter_get_info - return profiling data set for given file iterator
 518  * @iter: file iterator
 519  */
 520 void gcov_iter_free(struct gcov_iterator *iter)
 521 {
 522         vfree(iter->buffer);
 523         kfree(iter);
 524 }
 525 
 526 /**
 527  * gcov_iter_get_info - return profiling data set for given file iterator
 528  * @iter: file iterator
 529  */
 530 struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter)
 531 {
 532         return iter->info;
 533 }
 534 
 535 /**
 536  * gcov_iter_start - reset file iterator to starting position
 537  * @iter: file iterator
 538  */
 539 void gcov_iter_start(struct gcov_iterator *iter)
 540 {
 541         iter->pos = 0;
 542 }
 543 
 544 /**
 545  * gcov_iter_next - advance file iterator to next logical record
 546  * @iter: file iterator
 547  *
 548  * Return zero if new position is valid, non-zero if iterator has reached end.
 549  */
 550 int gcov_iter_next(struct gcov_iterator *iter)
 551 {
 552         if (iter->pos < iter->size)
 553                 iter->pos += ITER_STRIDE;
 554 
 555         if (iter->pos >= iter->size)
 556                 return -EINVAL;
 557 
 558         return 0;
 559 }
 560 
 561 /**
 562  * gcov_iter_write - write data for current pos to seq_file
 563  * @iter: file iterator
 564  * @seq: seq_file handle
 565  *
 566  * Return zero on success, non-zero otherwise.
 567  */
 568 int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq)
 569 {
 570         size_t len;
 571 
 572         if (iter->pos >= iter->size)
 573                 return -EINVAL;
 574 
 575         len = ITER_STRIDE;
 576         if (iter->pos + len > iter->size)
 577                 len = iter->size - iter->pos;
 578 
 579         seq_write(seq, iter->buffer + iter->pos, len);
 580 
 581         return 0;
 582 }