root/kernel/gcov/gcc_3_4.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. get_fn_size
13. get_fn_info
14. gcov_info_dup
15. gcov_info_free
16. get_func
17. get_type
18. gcov_iter_new
19. gcov_iter_free
20. gcov_iter_get_info
21. gcov_iter_start
22. gcov_iter_next
23. seq_write_gcov_u32
24. seq_write_gcov_u64
25. 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 3.4. Future versions of gcc may change the gcov
   5  *  format (as happened before), so all format-specific information needs
   6  *  to be kept modular and easily exchangeable.
   7  *
   8  *  This file is based on gcc-internal definitions. Functions and data
   9  *  structures are defined to be compatible with gcc counterparts.
  10  *  For a better understanding, refer to gcc source: gcc/gcov-io.h.
  11  *
  12  *    Copyright IBM Corp. 2009
  13  *    Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
  14  *
  15  *    Uses gcc-internal data definitions.
  16  */
  17 
  18 #include <linux/errno.h>
  19 #include <linux/slab.h>
  20 #include <linux/string.h>
  21 #include <linux/seq_file.h>
  22 #include <linux/vmalloc.h>
  23 #include "gcov.h"
  24 
  25 #define GCOV_COUNTERS           5
  26 
  27 static struct gcov_info *gcov_info_head;
  28 
  29 /**
  30  * struct gcov_fn_info - profiling meta data per function
  31  * @ident: object file-unique function identifier
  32  * @checksum: function checksum
  33  * @n_ctrs: number of values per counter type belonging to this function
  34  *
  35  * This data is generated by gcc during compilation and doesn't change
  36  * at run-time.
  37  */
  38 struct gcov_fn_info {
  39         unsigned int ident;
  40         unsigned int checksum;
  41         unsigned int n_ctrs[0];
  42 };
  43 
  44 /**
  45  * struct gcov_ctr_info - profiling data per counter type
  46  * @num: number of counter values for this type
  47  * @values: array of counter values for this type
  48  * @merge: merge function for counter values of this type (unused)
  49  *
  50  * This data is generated by gcc during compilation and doesn't change
  51  * at run-time with the exception of the values array.
  52  */
  53 struct gcov_ctr_info {
  54         unsigned int    num;
  55         gcov_type       *values;
  56         void            (*merge)(gcov_type *, unsigned int);
  57 };
  58 
  59 /**
  60  * struct gcov_info - profiling data per object file
  61  * @version: gcov version magic indicating the gcc version used for compilation
  62  * @next: list head for a singly-linked list
  63  * @stamp: time stamp
  64  * @filename: name of the associated gcov data file
  65  * @n_functions: number of instrumented functions
  66  * @functions: function data
  67  * @ctr_mask: mask specifying which counter types are active
  68  * @counts: counter data per counter type
  69  *
  70  * This data is generated by gcc during compilation and doesn't change
  71  * at run-time with the exception of the next pointer.
  72  */
  73 struct gcov_info {
  74         unsigned int                    version;
  75         struct gcov_info                *next;
  76         unsigned int                    stamp;
  77         const char                      *filename;
  78         unsigned int                    n_functions;
  79         const struct gcov_fn_info       *functions;
  80         unsigned int                    ctr_mask;
  81         struct gcov_ctr_info            counts[0];
  82 };
  83 
  84 /**
  85  * gcov_info_filename - return info filename
  86  * @info: profiling data set
  87  */
  88 const char *gcov_info_filename(struct gcov_info *info)
  89 {
  90         return info->filename;
  91 }
  92 
  93 /**
  94  * gcov_info_version - return info version
  95  * @info: profiling data set
  96  */
  97 unsigned int gcov_info_version(struct gcov_info *info)
  98 {
  99         return info->version;
 100 }
 101 
 102 /**
 103  * gcov_info_next - return next profiling data set
 104  * @info: profiling data set
 105  *
 106  * Returns next gcov_info following @info or first gcov_info in the chain if
 107  * @info is %NULL.
 108  */
 109 struct gcov_info *gcov_info_next(struct gcov_info *info)
 110 {
 111         if (!info)
 112                 return gcov_info_head;
 113 
 114         return info->next;
 115 }
 116 
 117 /**
 118  * gcov_info_link - link/add profiling data set to the list
 119  * @info: profiling data set
 120  */
 121 void gcov_info_link(struct gcov_info *info)
 122 {
 123         info->next = gcov_info_head;
 124         gcov_info_head = info;
 125 }
 126 
 127 /**
 128  * gcov_info_unlink - unlink/remove profiling data set from the list
 129  * @prev: previous profiling data set
 130  * @info: profiling data set
 131  */
 132 void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
 133 {
 134         if (prev)
 135                 prev->next = info->next;
 136         else
 137                 gcov_info_head = info->next;
 138 }
 139 
 140 /**
 141  * gcov_info_within_module - check if a profiling data set belongs to a module
 142  * @info: profiling data set
 143  * @mod: module
 144  *
 145  * Returns true if profiling data belongs module, false otherwise.
 146  */
 147 bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
 148 {
 149         return within_module((unsigned long)info, mod);
 150 }
 151 
 152 /* Symbolic links to be created for each profiling data file. */
 153 const struct gcov_link gcov_link[] = {
 154         { OBJ_TREE, "gcno" },   /* Link to .gcno file in $(objtree). */
 155         { 0, NULL},
 156 };
 157 
 158 /*
 159  * Determine whether a counter is active. Based on gcc magic. Doesn't change
 160  * at run-time.
 161  */
 162 static int counter_active(struct gcov_info *info, unsigned int type)
 163 {
 164         return (1 << type) & info->ctr_mask;
 165 }
 166 
 167 /* Determine number of active counters. Based on gcc magic. */
 168 static unsigned int num_counter_active(struct gcov_info *info)
 169 {
 170         unsigned int i;
 171         unsigned int result = 0;
 172 
 173         for (i = 0; i < GCOV_COUNTERS; i++) {
 174                 if (counter_active(info, i))
 175                         result++;
 176         }
 177         return result;
 178 }
 179 
 180 /**
 181  * gcov_info_reset - reset profiling data to zero
 182  * @info: profiling data set
 183  */
 184 void gcov_info_reset(struct gcov_info *info)
 185 {
 186         unsigned int active = num_counter_active(info);
 187         unsigned int i;
 188 
 189         for (i = 0; i < active; i++) {
 190                 memset(info->counts[i].values, 0,
 191                        info->counts[i].num * sizeof(gcov_type));
 192         }
 193 }
 194 
 195 /**
 196  * gcov_info_is_compatible - check if profiling data can be added
 197  * @info1: first profiling data set
 198  * @info2: second profiling data set
 199  *
 200  * Returns non-zero if profiling data can be added, zero otherwise.
 201  */
 202 int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
 203 {
 204         return (info1->stamp == info2->stamp);
 205 }
 206 
 207 /**
 208  * gcov_info_add - add up profiling data
 209  * @dest: profiling data set to which data is added
 210  * @source: profiling data set which is added
 211  *
 212  * Adds profiling counts of @source to @dest.
 213  */
 214 void gcov_info_add(struct gcov_info *dest, struct gcov_info *source)
 215 {
 216         unsigned int i;
 217         unsigned int j;
 218 
 219         for (i = 0; i < num_counter_active(dest); i++) {
 220                 for (j = 0; j < dest->counts[i].num; j++) {
 221                         dest->counts[i].values[j] +=
 222                                 source->counts[i].values[j];
 223                 }
 224         }
 225 }
 226 
 227 /* Get size of function info entry. Based on gcc magic. */
 228 static size_t get_fn_size(struct gcov_info *info)
 229 {
 230         size_t size;
 231 
 232         size = sizeof(struct gcov_fn_info) + num_counter_active(info) *
 233                sizeof(unsigned int);
 234         if (__alignof__(struct gcov_fn_info) > sizeof(unsigned int))
 235                 size = ALIGN(size, __alignof__(struct gcov_fn_info));
 236         return size;
 237 }
 238 
 239 /* Get address of function info entry. Based on gcc magic. */
 240 static struct gcov_fn_info *get_fn_info(struct gcov_info *info, unsigned int fn)
 241 {
 242         return (struct gcov_fn_info *)
 243                 ((char *) info->functions + fn * get_fn_size(info));
 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  */
 252 struct gcov_info *gcov_info_dup(struct gcov_info *info)
 253 {
 254         struct gcov_info *dup;
 255         unsigned int i;
 256         unsigned int active;
 257 
 258         /* Duplicate gcov_info. */
 259         active = num_counter_active(info);
 260         dup = kzalloc(struct_size(dup, counts, active), GFP_KERNEL);
 261         if (!dup)
 262                 return NULL;
 263         dup->version            = info->version;
 264         dup->stamp              = info->stamp;
 265         dup->n_functions        = info->n_functions;
 266         dup->ctr_mask           = info->ctr_mask;
 267         /* Duplicate filename. */
 268         dup->filename           = kstrdup(info->filename, GFP_KERNEL);
 269         if (!dup->filename)
 270                 goto err_free;
 271         /* Duplicate table of functions. */
 272         dup->functions = kmemdup(info->functions, info->n_functions *
 273                                  get_fn_size(info), GFP_KERNEL);
 274         if (!dup->functions)
 275                 goto err_free;
 276         /* Duplicate counter arrays. */
 277         for (i = 0; i < active ; i++) {
 278                 struct gcov_ctr_info *ctr = &info->counts[i];
 279                 size_t size = ctr->num * sizeof(gcov_type);
 280 
 281                 dup->counts[i].num = ctr->num;
 282                 dup->counts[i].merge = ctr->merge;
 283                 dup->counts[i].values = vmalloc(size);
 284                 if (!dup->counts[i].values)
 285                         goto err_free;
 286                 memcpy(dup->counts[i].values, ctr->values, size);
 287         }
 288         return dup;
 289 
 290 err_free:
 291         gcov_info_free(dup);
 292         return NULL;
 293 }
 294 
 295 /**
 296  * gcov_info_free - release memory for profiling data set duplicate
 297  * @info: profiling data set duplicate to free
 298  */
 299 void gcov_info_free(struct gcov_info *info)
 300 {
 301         unsigned int active = num_counter_active(info);
 302         unsigned int i;
 303 
 304         for (i = 0; i < active ; i++)
 305                 vfree(info->counts[i].values);
 306         kfree(info->functions);
 307         kfree(info->filename);
 308         kfree(info);
 309 }
 310 
 311 /**
 312  * struct type_info - iterator helper array
 313  * @ctr_type: counter type
 314  * @offset: index of the first value of the current function for this type
 315  *
 316  * This array is needed to convert the in-memory data format into the in-file
 317  * data format:
 318  *
 319  * In-memory:
 320  *   for each counter type
 321  *     for each function
 322  *       values
 323  *
 324  * In-file:
 325  *   for each function
 326  *     for each counter type
 327  *       values
 328  *
 329  * See gcc source gcc/gcov-io.h for more information on data organization.
 330  */
 331 struct type_info {
 332         int ctr_type;
 333         unsigned int offset;
 334 };
 335 
 336 /**
 337  * struct gcov_iterator - specifies current file position in logical records
 338  * @info: associated profiling data
 339  * @record: record type
 340  * @function: function number
 341  * @type: counter type
 342  * @count: index into values array
 343  * @num_types: number of counter types
 344  * @type_info: helper array to get values-array offset for current function
 345  */
 346 struct gcov_iterator {
 347         struct gcov_info *info;
 348 
 349         int record;
 350         unsigned int function;
 351         unsigned int type;
 352         unsigned int count;
 353 
 354         int num_types;
 355         struct type_info type_info[0];
 356 };
 357 
 358 static struct gcov_fn_info *get_func(struct gcov_iterator *iter)
 359 {
 360         return get_fn_info(iter->info, iter->function);
 361 }
 362 
 363 static struct type_info *get_type(struct gcov_iterator *iter)
 364 {
 365         return &iter->type_info[iter->type];
 366 }
 367 
 368 /**
 369  * gcov_iter_new - allocate and initialize profiling data iterator
 370  * @info: profiling data set to be iterated
 371  *
 372  * Return file iterator on success, %NULL otherwise.
 373  */
 374 struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
 375 {
 376         struct gcov_iterator *iter;
 377 
 378         iter = kzalloc(struct_size(iter, type_info, num_counter_active(info)),
 379                        GFP_KERNEL);
 380         if (iter)
 381                 iter->info = info;
 382 
 383         return iter;
 384 }
 385 
 386 /**
 387  * gcov_iter_free - release memory for iterator
 388  * @iter: file iterator to free
 389  */
 390 void gcov_iter_free(struct gcov_iterator *iter)
 391 {
 392         kfree(iter);
 393 }
 394 
 395 /**
 396  * gcov_iter_get_info - return profiling data set for given file iterator
 397  * @iter: file iterator
 398  */
 399 struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter)
 400 {
 401         return iter->info;
 402 }
 403 
 404 /**
 405  * gcov_iter_start - reset file iterator to starting position
 406  * @iter: file iterator
 407  */
 408 void gcov_iter_start(struct gcov_iterator *iter)
 409 {
 410         int i;
 411 
 412         iter->record = 0;
 413         iter->function = 0;
 414         iter->type = 0;
 415         iter->count = 0;
 416         iter->num_types = 0;
 417         for (i = 0; i < GCOV_COUNTERS; i++) {
 418                 if (counter_active(iter->info, i)) {
 419                         iter->type_info[iter->num_types].ctr_type = i;
 420                         iter->type_info[iter->num_types++].offset = 0;
 421                 }
 422         }
 423 }
 424 
 425 /* Mapping of logical record number to actual file content. */
 426 #define RECORD_FILE_MAGIC       0
 427 #define RECORD_GCOV_VERSION     1
 428 #define RECORD_TIME_STAMP       2
 429 #define RECORD_FUNCTION_TAG     3
 430 #define RECORD_FUNCTON_TAG_LEN  4
 431 #define RECORD_FUNCTION_IDENT   5
 432 #define RECORD_FUNCTION_CHECK   6
 433 #define RECORD_COUNT_TAG        7
 434 #define RECORD_COUNT_LEN        8
 435 #define RECORD_COUNT            9
 436 
 437 /**
 438  * gcov_iter_next - advance file iterator to next logical record
 439  * @iter: file iterator
 440  *
 441  * Return zero if new position is valid, non-zero if iterator has reached end.
 442  */
 443 int gcov_iter_next(struct gcov_iterator *iter)
 444 {
 445         switch (iter->record) {
 446         case RECORD_FILE_MAGIC:
 447         case RECORD_GCOV_VERSION:
 448         case RECORD_FUNCTION_TAG:
 449         case RECORD_FUNCTON_TAG_LEN:
 450         case RECORD_FUNCTION_IDENT:
 451         case RECORD_COUNT_TAG:
 452                 /* Advance to next record */
 453                 iter->record++;
 454                 break;
 455         case RECORD_COUNT:
 456                 /* Advance to next count */
 457                 iter->count++;
 458                 /* fall through */
 459         case RECORD_COUNT_LEN:
 460                 if (iter->count < get_func(iter)->n_ctrs[iter->type]) {
 461                         iter->record = 9;
 462                         break;
 463                 }
 464                 /* Advance to next counter type */
 465                 get_type(iter)->offset += iter->count;
 466                 iter->count = 0;
 467                 iter->type++;
 468                 /* fall through */
 469         case RECORD_FUNCTION_CHECK:
 470                 if (iter->type < iter->num_types) {
 471                         iter->record = 7;
 472                         break;
 473                 }
 474                 /* Advance to next function */
 475                 iter->type = 0;
 476                 iter->function++;
 477                 /* fall through */
 478         case RECORD_TIME_STAMP:
 479                 if (iter->function < iter->info->n_functions)
 480                         iter->record = 3;
 481                 else
 482                         iter->record = -1;
 483                 break;
 484         }
 485         /* Check for EOF. */
 486         if (iter->record == -1)
 487                 return -EINVAL;
 488         else
 489                 return 0;
 490 }
 491 
 492 /**
 493  * seq_write_gcov_u32 - write 32 bit number in gcov format to seq_file
 494  * @seq: seq_file handle
 495  * @v: value to be stored
 496  *
 497  * Number format defined by gcc: numbers are recorded in the 32 bit
 498  * unsigned binary form of the endianness of the machine generating the
 499  * file.
 500  */
 501 static int seq_write_gcov_u32(struct seq_file *seq, u32 v)
 502 {
 503         return seq_write(seq, &v, sizeof(v));
 504 }
 505 
 506 /**
 507  * seq_write_gcov_u64 - write 64 bit number in gcov format to seq_file
 508  * @seq: seq_file handle
 509  * @v: value to be stored
 510  *
 511  * Number format defined by gcc: numbers are recorded in the 32 bit
 512  * unsigned binary form of the endianness of the machine generating the
 513  * file. 64 bit numbers are stored as two 32 bit numbers, the low part
 514  * first.
 515  */
 516 static int seq_write_gcov_u64(struct seq_file *seq, u64 v)
 517 {
 518         u32 data[2];
 519 
 520         data[0] = (v & 0xffffffffUL);
 521         data[1] = (v >> 32);
 522         return seq_write(seq, data, sizeof(data));
 523 }
 524 
 525 /**
 526  * gcov_iter_write - write data for current pos to seq_file
 527  * @iter: file iterator
 528  * @seq: seq_file handle
 529  *
 530  * Return zero on success, non-zero otherwise.
 531  */
 532 int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq)
 533 {
 534         int rc = -EINVAL;
 535 
 536         switch (iter->record) {
 537         case RECORD_FILE_MAGIC:
 538                 rc = seq_write_gcov_u32(seq, GCOV_DATA_MAGIC);
 539                 break;
 540         case RECORD_GCOV_VERSION:
 541                 rc = seq_write_gcov_u32(seq, iter->info->version);
 542                 break;
 543         case RECORD_TIME_STAMP:
 544                 rc = seq_write_gcov_u32(seq, iter->info->stamp);
 545                 break;
 546         case RECORD_FUNCTION_TAG:
 547                 rc = seq_write_gcov_u32(seq, GCOV_TAG_FUNCTION);
 548                 break;
 549         case RECORD_FUNCTON_TAG_LEN:
 550                 rc = seq_write_gcov_u32(seq, 2);
 551                 break;
 552         case RECORD_FUNCTION_IDENT:
 553                 rc = seq_write_gcov_u32(seq, get_func(iter)->ident);
 554                 break;
 555         case RECORD_FUNCTION_CHECK:
 556                 rc = seq_write_gcov_u32(seq, get_func(iter)->checksum);
 557                 break;
 558         case RECORD_COUNT_TAG:
 559                 rc = seq_write_gcov_u32(seq,
 560                         GCOV_TAG_FOR_COUNTER(get_type(iter)->ctr_type));
 561                 break;
 562         case RECORD_COUNT_LEN:
 563                 rc = seq_write_gcov_u32(seq,
 564                                 get_func(iter)->n_ctrs[iter->type] * 2);
 565                 break;
 566         case RECORD_COUNT:
 567                 rc = seq_write_gcov_u64(seq,
 568                         iter->info->counts[iter->type].
 569                                 values[iter->count + get_type(iter)->offset]);
 570                 break;
 571         }
 572         return rc;
 573 }