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 /* Symbolic links to be created for each profiling data file. */
  25 const struct gcov_link gcov_link[] = {
  26         { OBJ_TREE, "gcno" },   /* Link to .gcno file in $(objtree). */
  27         { 0, NULL},
  28 };
  29
  30 /*
  31  * Determine whether a counter is active. Based on gcc magic. Doesn't change
  32  * at run-time.
  33  */
  34 static int counter_active(struct gcov_info *info, unsigned int type)
  35 {
  36         return (1 << type) & info->ctr_mask;
  37 }
  38
  39 /* Determine number of active counters. Based on gcc magic. */
  40 static unsigned int num_counter_active(struct gcov_info *info)
  41 {
  42         unsigned int i;
  43         unsigned int result = 0;
  44
  45         for (i = 0; i < GCOV_COUNTERS; i++) {
  46                 if (counter_active(info, i))
  47                         result++;
  48         }
  49         return result;
  50 }
  51
  52 /**
  53  * gcov_info_reset - reset profiling data to zero
  54  * @info: profiling data set
  55  */
  56 void gcov_info_reset(struct gcov_info *info)
  57 {
  58         unsigned int active = num_counter_active(info);
  59         unsigned int i;
  60
  61         for (i = 0; i < active; i++) {
  62                 memset(info->counts[i].values, 0,
  63                        info->counts[i].num * sizeof(gcov_type));
  64         }
  65 }
  66
  67 /**
  68  * gcov_info_is_compatible - check if profiling data can be added
  69  * @info1: first profiling data set
  70  * @info2: second profiling data set
  71  *
  72  * Returns non-zero if profiling data can be added, zero otherwise.
  73  */
  74 int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
  75 {
  76         return (info1->stamp == info2->stamp);
  77 }
  78
  79 /**
  80  * gcov_info_add - add up profiling data
  81  * @dest: profiling data set to which data is added
  82  * @source: profiling data set which is added
  83  *
  84  * Adds profiling counts of @source to @dest.
  85  */
  86 void gcov_info_add(struct gcov_info *dest, struct gcov_info *source)
  87 {
  88         unsigned int i;
  89         unsigned int j;
  90
  91         for (i = 0; i < num_counter_active(dest); i++) {
  92                 for (j = 0; j < dest->counts[i].num; j++) {
  93                         dest->counts[i].values[j] +=
  94                                 source->counts[i].values[j];
  95                 }
  96         }
  97 }
  98
  99 /* Get size of function info entry. Based on gcc magic. */
 100 static size_t get_fn_size(struct gcov_info *info)
 101 {
 102         size_t size;
 103
 104         size = sizeof(struct gcov_fn_info) + num_counter_active(info) *
 105                sizeof(unsigned int);
 106         if (__alignof__(struct gcov_fn_info) > sizeof(unsigned int))
 107                 size = ALIGN(size, __alignof__(struct gcov_fn_info));
 108         return size;
 109 }
 110
 111 /* Get address of function info entry. Based on gcc magic. */
 112 static struct gcov_fn_info *get_fn_info(struct gcov_info *info, unsigned int fn)
 113 {
 114         return (struct gcov_fn_info *)
 115                 ((char *) info->functions + fn * get_fn_size(info));
 116 }
 117
 118 /**
 119  * gcov_info_dup - duplicate profiling data set
 120  * @info: profiling data set to duplicate
 121  *
 122  * Return newly allocated duplicate on success, %NULL on error.
 123  */
 124 struct gcov_info *gcov_info_dup(struct gcov_info *info)
 125 {
 126         struct gcov_info *dup;
 127         unsigned int i;
 128         unsigned int active;
 129
 130         /* Duplicate gcov_info. */
 131         active = num_counter_active(info);
 132         dup = kzalloc(sizeof(struct gcov_info) +
 133                       sizeof(struct gcov_ctr_info) * active, GFP_KERNEL);
 134         if (!dup)
 135                 return NULL;
 136         dup->version            = info->version;
 137         dup->stamp              = info->stamp;
 138         dup->n_functions        = info->n_functions;
 139         dup->ctr_mask           = info->ctr_mask;
 140         /* Duplicate filename. */
 141         dup->filename           = kstrdup(info->filename, GFP_KERNEL);
 142         if (!dup->filename)
 143                 goto err_free;
 144         /* Duplicate table of functions. */
 145         dup->functions = kmemdup(info->functions, info->n_functions *
 146                                  get_fn_size(info), GFP_KERNEL);
 147         if (!dup->functions)
 148                 goto err_free;
 149         /* Duplicate counter arrays. */
 150         for (i = 0; i < active ; i++) {
 151                 struct gcov_ctr_info *ctr = &info->counts[i];
 152                 size_t size = ctr->num * sizeof(gcov_type);
 153
 154                 dup->counts[i].num = ctr->num;
 155                 dup->counts[i].merge = ctr->merge;
 156                 dup->counts[i].values = vmalloc(size);
 157                 if (!dup->counts[i].values)
 158                         goto err_free;
 159                 memcpy(dup->counts[i].values, ctr->values, size);
 160         }
 161         return dup;
 162
 163 err_free:
 164         gcov_info_free(dup);
 165         return NULL;
 166 }
 167
 168 /**
 169  * gcov_info_free - release memory for profiling data set duplicate
 170  * @info: profiling data set duplicate to free
 171  */
 172 void gcov_info_free(struct gcov_info *info)
 173 {
 174         unsigned int active = num_counter_active(info);
 175         unsigned int i;
 176
 177         for (i = 0; i < active ; i++)
 178                 vfree(info->counts[i].values);
 179         kfree(info->functions);
 180         kfree(info->filename);
 181         kfree(info);
 182 }
 183
 184 /**
 185  * struct type_info - iterator helper array
 186  * @ctr_type: counter type
 187  * @offset: index of the first value of the current function for this type
 188  *
 189  * This array is needed to convert the in-memory data format into the in-file
 190  * data format:
 191  *
 192  * In-memory:
 193  *   for each counter type
 194  *     for each function
 195  *       values
 196  *
 197  * In-file:
 198  *   for each function
 199  *     for each counter type
 200  *       values
 201  *
 202  * See gcc source gcc/gcov-io.h for more information on data organization.
 203  */
 204 struct type_info {
 205         int ctr_type;
 206         unsigned int offset;
 207 };
 208
 209 /**
 210  * struct gcov_iterator - specifies current file position in logical records
 211  * @info: associated profiling data
 212  * @record: record type
 213  * @function: function number
 214  * @type: counter type
 215  * @count: index into values array
 216  * @num_types: number of counter types
 217  * @type_info: helper array to get values-array offset for current function
 218  */
 219 struct gcov_iterator {
 220         struct gcov_info *info;
 221
 222         int record;
 223         unsigned int function;
 224         unsigned int type;
 225         unsigned int count;
 226
 227         int num_types;
 228         struct type_info type_info[0];
 229 };
 230
 231 static struct gcov_fn_info *get_func(struct gcov_iterator *iter)
 232 {
 233         return get_fn_info(iter->info, iter->function);
 234 }
 235
 236 static struct type_info *get_type(struct gcov_iterator *iter)
 237 {
 238         return &iter->type_info[iter->type];
 239 }
 240
 241 /**
 242  * gcov_iter_new - allocate and initialize profiling data iterator
 243  * @info: profiling data set to be iterated
 244  *
 245  * Return file iterator on success, %NULL otherwise.
 246  */
 247 struct gcov_iterator *gcov_iter_new(struct gcov_info *info)
 248 {
 249         struct gcov_iterator *iter;
 250
 251         iter = kzalloc(sizeof(struct gcov_iterator) +
 252                        num_counter_active(info) * sizeof(struct type_info),
 253                        GFP_KERNEL);
 254         if (iter)
 255                 iter->info = info;
 256
 257         return iter;
 258 }
 259
 260 /**
 261  * gcov_iter_free - release memory for iterator
 262  * @iter: file iterator to free
 263  */
 264 void gcov_iter_free(struct gcov_iterator *iter)
 265 {
 266         kfree(iter);
 267 }
 268
 269 /**
 270  * gcov_iter_get_info - return profiling data set for given file iterator
 271  * @iter: file iterator
 272  */
 273 struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter)
 274 {
 275         return iter->info;
 276 }
 277
 278 /**
 279  * gcov_iter_start - reset file iterator to starting position
 280  * @iter: file iterator
 281  */
 282 void gcov_iter_start(struct gcov_iterator *iter)
 283 {
 284         int i;
 285
 286         iter->record = 0;
 287         iter->function = 0;
 288         iter->type = 0;
 289         iter->count = 0;
 290         iter->num_types = 0;
 291         for (i = 0; i < GCOV_COUNTERS; i++) {
 292                 if (counter_active(iter->info, i)) {
 293                         iter->type_info[iter->num_types].ctr_type = i;
 294                         iter->type_info[iter->num_types++].offset = 0;
 295                 }
 296         }
 297 }
 298
 299 /* Mapping of logical record number to actual file content. */
 300 #define RECORD_FILE_MAGIC       0
 301 #define RECORD_GCOV_VERSION     1
 302 #define RECORD_TIME_STAMP       2
 303 #define RECORD_FUNCTION_TAG     3
 304 #define RECORD_FUNCTON_TAG_LEN  4
 305 #define RECORD_FUNCTION_IDENT   5
 306 #define RECORD_FUNCTION_CHECK   6
 307 #define RECORD_COUNT_TAG        7
 308 #define RECORD_COUNT_LEN        8
 309 #define RECORD_COUNT            9
 310
 311 /**
 312  * gcov_iter_next - advance file iterator to next logical record
 313  * @iter: file iterator
 314  *
 315  * Return zero if new position is valid, non-zero if iterator has reached end.
 316  */
 317 int gcov_iter_next(struct gcov_iterator *iter)
 318 {
 319         switch (iter->record) {
 320         case RECORD_FILE_MAGIC:
 321         case RECORD_GCOV_VERSION:
 322         case RECORD_FUNCTION_TAG:
 323         case RECORD_FUNCTON_TAG_LEN:
 324         case RECORD_FUNCTION_IDENT:
 325         case RECORD_COUNT_TAG:
 326                 /* Advance to next record */
 327                 iter->record++;
 328                 break;
 329         case RECORD_COUNT:
 330                 /* Advance to next count */
 331                 iter->count++;
 332                 /* fall through */
 333         case RECORD_COUNT_LEN:
 334                 if (iter->count < get_func(iter)->n_ctrs[iter->type]) {
 335                         iter->record = 9;
 336                         break;
 337                 }
 338                 /* Advance to next counter type */
 339                 get_type(iter)->offset += iter->count;
 340                 iter->count = 0;
 341                 iter->type++;
 342                 /* fall through */
 343         case RECORD_FUNCTION_CHECK:
 344                 if (iter->type < iter->num_types) {
 345                         iter->record = 7;
 346                         break;
 347                 }
 348                 /* Advance to next function */
 349                 iter->type = 0;
 350                 iter->function++;
 351                 /* fall through */
 352         case RECORD_TIME_STAMP:
 353                 if (iter->function < iter->info->n_functions)
 354                         iter->record = 3;
 355                 else
 356                         iter->record = -1;
 357                 break;
 358         }
 359         /* Check for EOF. */
 360         if (iter->record == -1)
 361                 return -EINVAL;
 362         else
 363                 return 0;
 364 }
 365
 366 /**
 367  * seq_write_gcov_u32 - write 32 bit number in gcov format to seq_file
 368  * @seq: seq_file handle
 369  * @v: value to be stored
 370  *
 371  * Number format defined by gcc: numbers are recorded in the 32 bit
 372  * unsigned binary form of the endianness of the machine generating the
 373  * file.
 374  */
 375 static int seq_write_gcov_u32(struct seq_file *seq, u32 v)
 376 {
 377         return seq_write(seq, &v, sizeof(v));
 378 }
 379
 380 /**
 381  * seq_write_gcov_u64 - write 64 bit number in gcov format to seq_file
 382  * @seq: seq_file handle
 383  * @v: value to be stored
 384  *
 385  * Number format defined by gcc: numbers are recorded in the 32 bit
 386  * unsigned binary form of the endianness of the machine generating the
 387  * file. 64 bit numbers are stored as two 32 bit numbers, the low part
 388  * first.
 389  */
 390 static int seq_write_gcov_u64(struct seq_file *seq, u64 v)
 391 {
 392         u32 data[2];
 393
 394         data[0] = (v & 0xffffffffUL);
 395         data[1] = (v >> 32);
 396         return seq_write(seq, data, sizeof(data));
 397 }
 398
 399 /**
 400  * gcov_iter_write - write data for current pos to seq_file
 401  * @iter: file iterator
 402  * @seq: seq_file handle
 403  *
 404  * Return zero on success, non-zero otherwise.
 405  */
 406 int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq)
 407 {
 408         int rc = -EINVAL;
 409
 410         switch (iter->record) {
 411         case RECORD_FILE_MAGIC:
 412                 rc = seq_write_gcov_u32(seq, GCOV_DATA_MAGIC);
 413                 break;
 414         case RECORD_GCOV_VERSION:
 415                 rc = seq_write_gcov_u32(seq, iter->info->version);
 416                 break;
 417         case RECORD_TIME_STAMP:
 418                 rc = seq_write_gcov_u32(seq, iter->info->stamp);
 419                 break;
 420         case RECORD_FUNCTION_TAG:
 421                 rc = seq_write_gcov_u32(seq, GCOV_TAG_FUNCTION);
 422                 break;
 423         case RECORD_FUNCTON_TAG_LEN:
 424                 rc = seq_write_gcov_u32(seq, 2);
 425                 break;
 426         case RECORD_FUNCTION_IDENT:
 427                 rc = seq_write_gcov_u32(seq, get_func(iter)->ident);
 428                 break;
 429         case RECORD_FUNCTION_CHECK:
 430                 rc = seq_write_gcov_u32(seq, get_func(iter)->checksum);
 431                 break;
 432         case RECORD_COUNT_TAG:
 433                 rc = seq_write_gcov_u32(seq,
 434                         GCOV_TAG_FOR_COUNTER(get_type(iter)->ctr_type));
 435                 break;
 436         case RECORD_COUNT_LEN:
 437                 rc = seq_write_gcov_u32(seq,
 438                                 get_func(iter)->n_ctrs[iter->type] * 2);
 439                 break;
 440         case RECORD_COUNT:
 441                 rc = seq_write_gcov_u64(seq,
 442                         iter->info->counts[iter->type].
 443                                 values[iter->count + get_type(iter)->offset]);
 444                 break;
 445         }
 446         return rc;
 447 }