kernel/gcov/gcc_3_4.c

   1 /*
   2  *  This code provides functions to handle gcc's profiling data format
   3  *  introduced with gcc 3.4. Future versions of gcc may change the gcov
   4  *  format (as happened before), so all format-specific information needs
   5  *  to be kept modular and easily exchangeable.
   6  *
   7  *  This file is based on gcc-internal definitions. Functions and data
   8  *  structures are defined to be compatible with gcc counterparts.
   9  *  For a better understanding, refer to gcc source: gcc/gcov-io.h.
  10  *
  11  *    Copyright IBM Corp. 2009
  12  *    Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
  13  *
  14  *    Uses gcc-internal data definitions.
  15  */
  16
  17 #include <linux/errno.h>
  18 #include <linux/slab.h>
  19 #include <linux/string.h>
  20 #include <linux/seq_file.h>
  21 #include <linux/vmalloc.h>
  22 #include "gcov.h"
  23
  24 #define GCOV_COUNTERS           5
  25
  26 static struct gcov_info *gcov_info_head;
  27
  28 /**
  29  * struct gcov_fn_info - profiling meta data per function
  30  * @ident: object file-unique function identifier
  31  * @checksum: function checksum
  32  * @n_ctrs: number of values per counter type belonging to this function
  33  *
  34  * This data is generated by gcc during compilation and doesn't change
  35  * at run-time.
  36  */
  37 struct gcov_fn_info {
  38         unsigned int ident;
  39         unsigned int checksum;
  40         unsigned int n_ctrs[0];
  41 };
  42
  43 /**
  44  * struct gcov_ctr_info - profiling data per counter type
  45  * @num: number of counter values for this type
  46  * @values: array of counter values for this type
  47  * @merge: merge function for counter values of this type (unused)
  48  *
  49  * This data is generated by gcc during compilation and doesn't change
  50  * at run-time with the exception of the values array.
  51  */
  52 struct gcov_ctr_info {
  53         unsigned int    num;
  54         gcov_type       *values;
  55         void            (*merge)(gcov_type *, unsigned int);
  56 };
  57
  58 /**
  59  * struct gcov_info - profiling data per object file
  60  * @version: gcov version magic indicating the gcc version used for compilation
  61  * @next: list head for a singly-linked list
  62  * @stamp: time stamp
  63  * @filename: name of the associated gcov data file
  64  * @n_functions: number of instrumented functions
  65  * @functions: function data
  66  * @ctr_mask: mask specifying which counter types are active
  67  * @counts: counter data per counter type
  68  *
  69  * This data is generated by gcc during compilation and doesn't change
  70  * at run-time with the exception of the next pointer.
  71  */
  72 struct gcov_info {
  73         unsigned int                    version;
  74         struct gcov_info                *next;
  75         unsigned int                    stamp;
  76         const char                      *filename;
  77         unsigned int                    n_functions;
  78         const struct gcov_fn_info       *functions;
  79         unsigned int                    ctr_mask;
  80         struct gcov_ctr_info            counts[0];
  81 };
  82
  83 /**
  84  * gcov_info_filename - return info filename
  85  * @info: profiling data set
  86  */
  87 const char *gcov_info_filename(struct gcov_info *info)
  88 {
  89         return info->filename;
  90 }
  91
  92 /**
  93  * gcov_info_version - return info version
  94  * @info: profiling data set
  95  */
  96 unsigned int gcov_info_version(struct gcov_info *info)
  97 {
  98         return info->version;
  99 }
 100
 101 /**
 102  * gcov_info_next - return next profiling data set
 103  * @info: profiling data set
 104  *
 105  * Returns next gcov_info following @info or first gcov_info in the chain if
 106  * @info is %NULL.
 107  */
 108 struct gcov_info *gcov_info_next(struct gcov_info *info)
 109 {
 110         if (!info)
 111                 return gcov_info_head;
 112
 113         return info->next;
 114 }
 115
 116 /**
 117  * gcov_info_link - link/add profiling data set to the list
 118  * @info: profiling data set
 119  */
 120 void gcov_info_link(struct gcov_info *info)
 121 {
 122         info->next = gcov_info_head;
 123         gcov_info_head = info;
 124 }
 125
 126 /**
 127  * gcov_info_unlink - unlink/remove profiling data set from the list
 128  * @prev: previous profiling data set
 129  * @info: profiling data set
 130  */
 131 void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
 132 {
 133         if (prev)
 134                 prev->next = info->next;
 135         else
 136                 gcov_info_head = info->next;
 137 }
 138
 139 /* Symbolic links to be created for each profiling data file. */
 140 const struct gcov_link gcov_link[] = {
 141         { OBJ_TREE, "gcno" },   /* Link to .gcno file in $(objtree). */
 142         { 0, NULL},
 143 };
 144
 145 /*
 146  * Determine whether a counter is active. Based on gcc magic. Doesn't change
 147  * at run-time.
 148  */
 149 static int counter_active(struct gcov_info *info, unsigned int type)
 150 {
 151         return (1 << type) & info->ctr_mask;
 152 }
 153
 154 /* Determine number of active counters. Based on gcc magic. */
 155 static unsigned int num_counter_active(struct gcov_info *info)
 156 {
 157         unsigned int i;
 158         unsigned int result = 0;
 159
 160         for (i = 0; i < GCOV_COUNTERS; i++) {
 161                 if (counter_active(info, i))
 162                         result++;
 163         }
 164         return result;
 165 }
 166
 167 /**
 168  * gcov_info_reset - reset profiling data to zero
 169  * @info: profiling data set
 170  */
 171 void gcov_info_reset(struct gcov_info *info)
 172 {
 173         unsigned int active = num_counter_active(info);
 174         unsigned int i;
 175
 176         for (i = 0; i < active; i++) {
 177                 memset(info->counts[i].values, 0,
 178                        info->counts[i].num * sizeof(gcov_type));
 179         }
 180 }
 181
 182 /**
 183  * gcov_info_is_compatible - check if profiling data can be added
 184  * @info1: first profiling data set
 185  * @info2: second profiling data set
 186  *
 187  * Returns non-zero if profiling data can be added, zero otherwise.
 188  */
 189 int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
 190 {
 191         return (info1->stamp == info2->stamp);
 192 }
 193
 194 /**
 195  * gcov_info_add - add up profiling data
 196  * @dest: profiling data set to which data is added
 197  * @source: profiling data set which is added
 198  *
 199  * Adds profiling counts of @source to @dest.
 200  */
 201 void gcov_info_add(struct gcov_info *dest, struct gcov_info *source)
 202 {
 203         unsigned int i;
 204         unsigned int j;
 205
 206         for (i = 0; i < num_counter_active(dest); i++) {
 207                 for (j = 0; j < dest->counts[i].num; j++) {
 208                         dest->counts[i].values[j] +=
 209                                 source->counts[i].values[j];
 210                 }
 211         }
 212 }
 213
 214 /* Get size of function info entry. Based on gcc magic. */
 215 static size_t get_fn_size(struct gcov_info *info)
 216 {
 217         size_t size;
 218
 219         size = sizeof(struct gcov_fn_info) + num_counter_active(info) *
 220                sizeof(unsigned int);
 221         if (__alignof__(struct gcov_fn_info) > sizeof(unsigned int))
 222                 size = ALIGN(size, __alignof__(struct gcov_fn_info));
 223         return size;
 224 }
 225
 226 /* Get address of function info entry. Based on gcc magic. */
 227 static struct gcov_fn_info *get_fn_info(struct gcov_info *info, unsigned int fn)
 228 {
 229         return (struct gcov_fn_info *)
 230                 ((char *) info->functions + fn * get_fn_size(info));
 231 }
 232
 233 /**
 234  * gcov_info_dup - duplicate profiling data set
 235  * @info: profiling data set to duplicate
 236  *
 237  * Return newly allocated duplicate on success, %NULL on error.
 238  */
 239 struct gcov_info *gcov_info_dup(struct gcov_info *info)
 240 {
 241         struct gcov_info *dup;
 242         unsigned int i;
 243         unsigned int active;
 244
 245         /* Duplicate gcov_info. */
 246         active = num_counter_active(info);
 247         dup = kzalloc(sizeof(struct gcov_info) +
 248                       sizeof(struct gcov_ctr_info) * active, GFP_KERNEL);
 249         if (!dup)
 250                 return NULL;
 251         dup->version            = info->version;
 252         dup->stamp              = info->stamp;
 253         dup->n_functions        = info->n_functions;
 254         dup->ctr_mask           = info->ctr_mask;
 255         /* Duplicate filename. */
 256         dup->filename           = kstrdup(info->filename, GFP_KERNEL);
 257         if (!dup->filename)
 258                 goto err_free;
 259         /* Duplicate table of functions. */
 260         dup->functions = kmemdup(info->functions, info->n_functions *
 261                                  get_fn_size(info), GFP_KERNEL);
 262         if (!dup->functions)
 263                 goto err_free;
 264         /* Duplicate counter arrays. */
 265         for (i = 0; i < active ; i++) {
 266                 struct gcov_ctr_info *ctr = &info->counts[i];
 267                 size_t size = ctr->num * sizeof(gcov_type);
 268
 269                 dup->counts[i].num = ctr->num;
 270                 dup->counts[i].merge = ctr->merge;
 271                 dup->counts[i].values = vmalloc(size);
 272                 if (!dup->counts[i].values)
 273                         goto err_free;
 274                 memcpy(dup->counts[i].values, ctr->values, size);
 275         }
 276         return dup;
 277
 278 err_free:
 279         gcov_info_free(dup);
 280         return NULL;
 281 }
 282
 283 /**
 284  * gcov_info_free - release memory for profiling data set duplicate
 285  * @info: profiling data set duplicate to free
 286  */
 287 void gcov_info_free(struct gcov_info *info)
 288 {
 289         unsigned int active = num_counter_active(info);
 290         unsigned int i;
 291
 292         for (i = 0; i < active ; i++)
 293                 vfree(info->counts[i].values);
 294         kfree(info->functions);
 295         kfree(info->filename);
 296         kfree(info);
 297 }
 298
 299 /**
 300  * struct type_info - iterator helper array
 301  * @ctr_type: counter type
 302  * @offset: index of the first value of the current function for this type
 303  *
 304  * This array is needed to convert the in-memory data format into the in-file
 305  * data format:
 306  *
 307  * In-memory:
 308  *   for each counter type
 309  *     for each function
 310  *       values
 311  *
 312  * In-file:
 313  *   for each function
 314  *     for each counter type
 315  *       values
 316  *
 317  * See gcc source gcc/gcov-io.h for more information on data organization.
 318  */
 319 struct type_info {
 320         int ctr_type;
 321         unsigned int offset;
 322 };
 323
 324 /**
 325  * struct gcov_iterator - specifies current file position in logical records
 326  * @info: associated profiling data
 327  * @record: record type
 328  * @function: function number
 329  * @type: counter type
 330  * @count: index into values array
 331  * @num_types: number of counter types
 332  * @type_info: helper array to get values-array offset for current function
 333  */
 334 struct gcov_iterator {
 335         struct gcov_info *info;
 336
 337         int record;
 338         unsigned int function;
 339         unsigned int type;
 340         unsigned int count;
 341
 342         int num_types;
 343         struct type_info type_info[0];
 344 };
 345
 346 static struct gcov_fn_info *get_func(struct gcov_iterator *iter)
 347 {
 348         return get_fn_info(iter->info, iter->function);
 349 }
 350
 351 static struct type_info *get_type(struct gcov_iterator *iter)
 352 {
 353         return &iter->type_info[iter->type];
 354 }
 355
 356 /**
 357  * gcov_iter_new - allocate and initialize profiling data iterator
 358  * @info: profiling data set to be iterated
 359  *
 360  * Return file iterator on success, %NULL otherwise.
 361  */
 362 struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
 363 {
 364         struct gcov_iterator *iter;
 365
 366         iter = kzalloc(sizeof(struct gcov_iterator) +
 367                        num_counter_active(info) * sizeof(struct type_info),
 368                        GFP_KERNEL);
 369         if (iter)
 370                 iter->info = info;
 371
 372         return iter;
 373 }
 374
 375 /**
 376  * gcov_iter_free - release memory for iterator
 377  * @iter: file iterator to free
 378  */
 379 void gcov_iter_free(struct gcov_iterator *iter)
 380 {
 381         kfree(iter);
 382 }
 383
 384 /**
 385  * gcov_iter_get_info - return profiling data set for given file iterator
 386  * @iter: file iterator
 387  */
 388 struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter)
 389 {
 390         return iter->info;
 391 }
 392
 393 /**
 394  * gcov_iter_start - reset file iterator to starting position
 395  * @iter: file iterator
 396  */
 397 void gcov_iter_start(struct gcov_iterator *iter)
 398 {
 399         int i;
 400
 401         iter->record = 0;
 402         iter->function = 0;
 403         iter->type = 0;
 404         iter->count = 0;
 405         iter->num_types = 0;
 406         for (i = 0; i < GCOV_COUNTERS; i++) {
 407                 if (counter_active(iter->info, i)) {
 408                         iter->type_info[iter->num_types].ctr_type = i;
 409                         iter->type_info[iter->num_types++].offset = 0;
 410                 }
 411         }
 412 }
 413
 414 /* Mapping of logical record number to actual file content. */
 415 #define RECORD_FILE_MAGIC       0
 416 #define RECORD_GCOV_VERSION     1
 417 #define RECORD_TIME_STAMP       2
 418 #define RECORD_FUNCTION_TAG     3
 419 #define RECORD_FUNCTON_TAG_LEN  4
 420 #define RECORD_FUNCTION_IDENT   5
 421 #define RECORD_FUNCTION_CHECK   6
 422 #define RECORD_COUNT_TAG        7
 423 #define RECORD_COUNT_LEN        8
 424 #define RECORD_COUNT            9
 425
 426 /**
 427  * gcov_iter_next - advance file iterator to next logical record
 428  * @iter: file iterator
 429  *
 430  * Return zero if new position is valid, non-zero if iterator has reached end.
 431  */
 432 int gcov_iter_next(struct gcov_iterator *iter)
 433 {
 434         switch (iter->record) {
 435         case RECORD_FILE_MAGIC:
 436         case RECORD_GCOV_VERSION:
 437         case RECORD_FUNCTION_TAG:
 438         case RECORD_FUNCTON_TAG_LEN:
 439         case RECORD_FUNCTION_IDENT:
 440         case RECORD_COUNT_TAG:
 441                 /* Advance to next record */
 442                 iter->record++;
 443                 break;
 444         case RECORD_COUNT:
 445                 /* Advance to next count */
 446                 iter->count++;
 447                 /* fall through */
 448         case RECORD_COUNT_LEN:
 449                 if (iter->count < get_func(iter)->n_ctrs[iter->type]) {
 450                         iter->record = 9;
 451                         break;
 452                 }
 453                 /* Advance to next counter type */
 454                 get_type(iter)->offset += iter->count;
 455                 iter->count = 0;
 456                 iter->type++;
 457                 /* fall through */
 458         case RECORD_FUNCTION_CHECK:
 459                 if (iter->type < iter->num_types) {
 460                         iter->record = 7;
 461                         break;
 462                 }
 463                 /* Advance to next function */
 464                 iter->type = 0;
 465                 iter->function++;
 466                 /* fall through */
 467         case RECORD_TIME_STAMP:
 468                 if (iter->function < iter->info->n_functions)
 469                         iter->record = 3;
 470                 else
 471                         iter->record = -1;
 472                 break;
 473         }
 474         /* Check for EOF. */
 475         if (iter->record == -1)
 476                 return -EINVAL;
 477         else
 478                 return 0;
 479 }
 480
 481 /**
 482  * seq_write_gcov_u32 - write 32 bit number in gcov format to seq_file
 483  * @seq: seq_file handle
 484  * @v: value to be stored
 485  *
 486  * Number format defined by gcc: numbers are recorded in the 32 bit
 487  * unsigned binary form of the endianness of the machine generating the
 488  * file.
 489  */
 490 static int seq_write_gcov_u32(struct seq_file *seq, u32 v)
 491 {
 492         return seq_write(seq, &v, sizeof(v));
 493 }
 494
 495 /**
 496  * seq_write_gcov_u64 - write 64 bit number in gcov format to seq_file
 497  * @seq: seq_file handle
 498  * @v: value to be stored
 499  *
 500  * Number format defined by gcc: numbers are recorded in the 32 bit
 501  * unsigned binary form of the endianness of the machine generating the
 502  * file. 64 bit numbers are stored as two 32 bit numbers, the low part
 503  * first.
 504  */
 505 static int seq_write_gcov_u64(struct seq_file *seq, u64 v)
 506 {
 507         u32 data[2];
 508
 509         data[0] = (v & 0xffffffffUL);
 510         data[1] = (v >> 32);
 511         return seq_write(seq, data, sizeof(data));
 512 }
 513
 514 /**
 515  * gcov_iter_write - write data for current pos to seq_file
 516  * @iter: file iterator
 517  * @seq: seq_file handle
 518  *
 519  * Return zero on success, non-zero otherwise.
 520  */
 521 int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq)
 522 {
 523         int rc = -EINVAL;
 524
 525         switch (iter->record) {
 526         case RECORD_FILE_MAGIC:
 527                 rc = seq_write_gcov_u32(seq, GCOV_DATA_MAGIC);
 528                 break;
 529         case RECORD_GCOV_VERSION:
 530                 rc = seq_write_gcov_u32(seq, iter->info->version);
 531                 break;
 532         case RECORD_TIME_STAMP:
 533                 rc = seq_write_gcov_u32(seq, iter->info->stamp);
 534                 break;
 535         case RECORD_FUNCTION_TAG:
 536                 rc = seq_write_gcov_u32(seq, GCOV_TAG_FUNCTION);
 537                 break;
 538         case RECORD_FUNCTON_TAG_LEN:
 539                 rc = seq_write_gcov_u32(seq, 2);
 540                 break;
 541         case RECORD_FUNCTION_IDENT:
 542                 rc = seq_write_gcov_u32(seq, get_func(iter)->ident);
 543                 break;
 544         case RECORD_FUNCTION_CHECK:
 545                 rc = seq_write_gcov_u32(seq, get_func(iter)->checksum);
 546                 break;
 547         case RECORD_COUNT_TAG:
 548                 rc = seq_write_gcov_u32(seq,
 549                         GCOV_TAG_FOR_COUNTER(get_type(iter)->ctr_type));
 550                 break;
 551         case RECORD_COUNT_LEN:
 552                 rc = seq_write_gcov_u32(seq,
 553                                 get_func(iter)->n_ctrs[iter->type] * 2);
 554                 break;
 555         case RECORD_COUNT:
 556                 rc = seq_write_gcov_u64(seq,
 557                         iter->info->counts[iter->type].
 558                                 values[iter->count + get_type(iter)->offset]);
 559                 break;
 560         }
 561         return rc;
 562 }