kernel/gcov/gcc_4_7.c

   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/mm.h>
  19 #include "gcov.h"
  20
  21 #if (__GNUC__ >= 14)
  22 #define GCOV_COUNTERS                   9
  23 #elif (__GNUC__ >= 10)
  24 #define GCOV_COUNTERS                   8
  25 #elif (__GNUC__ >= 7)
  26 #define GCOV_COUNTERS                   9
  27 #elif (__GNUC__ > 5) || (__GNUC__ == 5 && __GNUC_MINOR__ >= 1)
  28 #define GCOV_COUNTERS                   10
  29 #else
  30 #define GCOV_COUNTERS                   9
  31 #endif
  32
  33 #define GCOV_TAG_FUNCTION_LENGTH        3
  34
  35 /* Since GCC 12.1 sizes are in BYTES and not in WORDS (4B). */
  36 #if (__GNUC__ >= 12)
  37 #define GCOV_UNIT_SIZE                          4
  38 #else
  39 #define GCOV_UNIT_SIZE                          1
  40 #endif
  41
  42 static struct gcov_info *gcov_info_head;
  43
  44 /**
  45  * struct gcov_ctr_info - information about counters for a single function
  46  * @num: number of counter values for this type
  47  * @values: array of counter values for this type
  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 };
  56
  57 /**
  58  * struct gcov_fn_info - profiling meta data per function
  59  * @key: comdat key
  60  * @ident: unique ident of function
  61  * @lineno_checksum: function lineo_checksum
  62  * @cfg_checksum: function cfg checksum
  63  * @ctrs: instrumented counters
  64  *
  65  * This data is generated by gcc during compilation and doesn't change
  66  * at run-time.
  67  *
  68  * Information about a single function.  This uses the trailing array
  69  * idiom. The number of counters is determined from the merge pointer
  70  * array in gcov_info.  The key is used to detect which of a set of
  71  * comdat functions was selected -- it points to the gcov_info object
  72  * of the object file containing the selected comdat function.
  73  */
  74 struct gcov_fn_info {
  75         const struct gcov_info *key;
  76         unsigned int ident;
  77         unsigned int lineno_checksum;
  78         unsigned int cfg_checksum;
  79         struct gcov_ctr_info ctrs[];
  80 };
  81
  82 /**
  83  * struct gcov_info - profiling data per object file
  84  * @version: gcov version magic indicating the gcc version used for compilation
  85  * @next: list head for a singly-linked list
  86  * @stamp: uniquifying time stamp
  87  * @checksum: unique object checksum
  88  * @filename: name of the associated gcov data file
  89  * @merge: merge functions (null for unused counter type)
  90  * @n_functions: number of instrumented functions
  91  * @functions: pointer to pointers to function information
  92  *
  93  * This data is generated by gcc during compilation and doesn't change
  94  * at run-time with the exception of the next pointer.
  95  */
  96 struct gcov_info {
  97         unsigned int version;
  98         struct gcov_info *next;
  99         unsigned int stamp;
 100  /* Since GCC 12.1 a checksum field is added. */
 101 #if (__GNUC__ >= 12)
 102         unsigned int checksum;
 103 #endif
 104         const char *filename;
 105         void (*merge[GCOV_COUNTERS])(gcov_type *, unsigned int);
 106         unsigned int n_functions;
 107         struct gcov_fn_info **functions;
 108 };
 109
 110 /**
 111  * gcov_info_filename - return info filename
 112  * @info: profiling data set
 113  */
 114 const char *gcov_info_filename(struct gcov_info *info)
 115 {
 116         return info->filename;
 117 }
 118
 119 /**
 120  * gcov_info_version - return info version
 121  * @info: profiling data set
 122  */
 123 unsigned int gcov_info_version(struct gcov_info *info)
 124 {
 125         return info->version;
 126 }
 127
 128 /**
 129  * gcov_info_next - return next profiling data set
 130  * @info: profiling data set
 131  *
 132  * Returns next gcov_info following @info or first gcov_info in the chain if
 133  * @info is %NULL.
 134  */
 135 struct gcov_info *gcov_info_next(struct gcov_info *info)
 136 {
 137         if (!info)
 138                 return gcov_info_head;
 139
 140         return info->next;
 141 }
 142
 143 /**
 144  * gcov_info_link - link/add profiling data set to the list
 145  * @info: profiling data set
 146  */
 147 void gcov_info_link(struct gcov_info *info)
 148 {
 149         info->next = gcov_info_head;
 150         gcov_info_head = info;
 151 }
 152
 153 /**
 154  * gcov_info_unlink - unlink/remove profiling data set from the list
 155  * @prev: previous profiling data set
 156  * @info: profiling data set
 157  */
 158 void gcov_info_unlink(struct gcov_info *prev, struct gcov_info *info)
 159 {
 160         if (prev)
 161                 prev->next = info->next;
 162         else
 163                 gcov_info_head = info->next;
 164 }
 165
 166 /**
 167  * gcov_info_within_module - check if a profiling data set belongs to a module
 168  * @info: profiling data set
 169  * @mod: module
 170  *
 171  * Returns true if profiling data belongs module, false otherwise.
 172  */
 173 bool gcov_info_within_module(struct gcov_info *info, struct module *mod)
 174 {
 175         return within_module((unsigned long)info, mod);
 176 }
 177
 178 /* Symbolic links to be created for each profiling data file. */
 179 const struct gcov_link gcov_link[] = {
 180         { OBJ_TREE, "gcno" },   /* Link to .gcno file in $(objtree). */
 181         { 0, NULL},
 182 };
 183
 184 /*
 185  * Determine whether a counter is active. Doesn't change at run-time.
 186  */
 187 static int counter_active(struct gcov_info *info, unsigned int type)
 188 {
 189         return info->merge[type] ? 1 : 0;
 190 }
 191
 192 /* Determine number of active counters. Based on gcc magic. */
 193 static unsigned int num_counter_active(struct gcov_info *info)
 194 {
 195         unsigned int i;
 196         unsigned int result = 0;
 197
 198         for (i = 0; i < GCOV_COUNTERS; i++) {
 199                 if (counter_active(info, i))
 200                         result++;
 201         }
 202         return result;
 203 }
 204
 205 /**
 206  * gcov_info_reset - reset profiling data to zero
 207  * @info: profiling data set
 208  */
 209 void gcov_info_reset(struct gcov_info *info)
 210 {
 211         struct gcov_ctr_info *ci_ptr;
 212         unsigned int fi_idx;
 213         unsigned int ct_idx;
 214
 215         for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
 216                 ci_ptr = info->functions[fi_idx]->ctrs;
 217
 218                 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
 219                         if (!counter_active(info, ct_idx))
 220                                 continue;
 221
 222                         memset(ci_ptr->values, 0,
 223                                         sizeof(gcov_type) * ci_ptr->num);
 224                         ci_ptr++;
 225                 }
 226         }
 227 }
 228
 229 /**
 230  * gcov_info_is_compatible - check if profiling data can be added
 231  * @info1: first profiling data set
 232  * @info2: second profiling data set
 233  *
 234  * Returns non-zero if profiling data can be added, zero otherwise.
 235  */
 236 int gcov_info_is_compatible(struct gcov_info *info1, struct gcov_info *info2)
 237 {
 238         return (info1->stamp == info2->stamp);
 239 }
 240
 241 /**
 242  * gcov_info_add - add up profiling data
 243  * @dst: profiling data set to which data is added
 244  * @src: profiling data set which is added
 245  *
 246  * Adds profiling counts of @src to @dst.
 247  */
 248 void gcov_info_add(struct gcov_info *dst, struct gcov_info *src)
 249 {
 250         struct gcov_ctr_info *dci_ptr;
 251         struct gcov_ctr_info *sci_ptr;
 252         unsigned int fi_idx;
 253         unsigned int ct_idx;
 254         unsigned int val_idx;
 255
 256         for (fi_idx = 0; fi_idx < src->n_functions; fi_idx++) {
 257                 dci_ptr = dst->functions[fi_idx]->ctrs;
 258                 sci_ptr = src->functions[fi_idx]->ctrs;
 259
 260                 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
 261                         if (!counter_active(src, ct_idx))
 262                                 continue;
 263
 264                         for (val_idx = 0; val_idx < sci_ptr->num; val_idx++)
 265                                 dci_ptr->values[val_idx] +=
 266                                         sci_ptr->values[val_idx];
 267
 268                         dci_ptr++;
 269                         sci_ptr++;
 270                 }
 271         }
 272 }
 273
 274 /**
 275  * gcov_info_dup - duplicate profiling data set
 276  * @info: profiling data set to duplicate
 277  *
 278  * Return newly allocated duplicate on success, %NULL on error.
 279  */
 280 struct gcov_info *gcov_info_dup(struct gcov_info *info)
 281 {
 282         struct gcov_info *dup;
 283         struct gcov_ctr_info *dci_ptr; /* dst counter info */
 284         struct gcov_ctr_info *sci_ptr; /* src counter info */
 285         unsigned int active;
 286         unsigned int fi_idx; /* function info idx */
 287         unsigned int ct_idx; /* counter type idx */
 288         size_t fi_size; /* function info size */
 289         size_t cv_size; /* counter values size */
 290
 291         dup = kmemdup(info, sizeof(*dup), GFP_KERNEL);
 292         if (!dup)
 293                 return NULL;
 294
 295         dup->next = NULL;
 296         dup->filename = NULL;
 297         dup->functions = NULL;
 298
 299         dup->filename = kstrdup(info->filename, GFP_KERNEL);
 300         if (!dup->filename)
 301                 goto err_free;
 302
 303         dup->functions = kcalloc(info->n_functions,
 304                                  sizeof(struct gcov_fn_info *), GFP_KERNEL);
 305         if (!dup->functions)
 306                 goto err_free;
 307
 308         active = num_counter_active(info);
 309         fi_size = sizeof(struct gcov_fn_info);
 310         fi_size += sizeof(struct gcov_ctr_info) * active;
 311
 312         for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
 313                 dup->functions[fi_idx] = kzalloc(fi_size, GFP_KERNEL);
 314                 if (!dup->functions[fi_idx])
 315                         goto err_free;
 316
 317                 *(dup->functions[fi_idx]) = *(info->functions[fi_idx]);
 318
 319                 sci_ptr = info->functions[fi_idx]->ctrs;
 320                 dci_ptr = dup->functions[fi_idx]->ctrs;
 321
 322                 for (ct_idx = 0; ct_idx < active; ct_idx++) {
 323
 324                         cv_size = sizeof(gcov_type) * sci_ptr->num;
 325
 326                         dci_ptr->values = kvmalloc(cv_size, GFP_KERNEL);
 327
 328                         if (!dci_ptr->values)
 329                                 goto err_free;
 330
 331                         dci_ptr->num = sci_ptr->num;
 332                         memcpy(dci_ptr->values, sci_ptr->values, cv_size);
 333
 334                         sci_ptr++;
 335                         dci_ptr++;
 336                 }
 337         }
 338
 339         return dup;
 340 err_free:
 341         gcov_info_free(dup);
 342         return NULL;
 343 }
 344
 345 /**
 346  * gcov_info_free - release memory for profiling data set duplicate
 347  * @info: profiling data set duplicate to free
 348  */
 349 void gcov_info_free(struct gcov_info *info)
 350 {
 351         unsigned int active;
 352         unsigned int fi_idx;
 353         unsigned int ct_idx;
 354         struct gcov_ctr_info *ci_ptr;
 355
 356         if (!info->functions)
 357                 goto free_info;
 358
 359         active = num_counter_active(info);
 360
 361         for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
 362                 if (!info->functions[fi_idx])
 363                         continue;
 364
 365                 ci_ptr = info->functions[fi_idx]->ctrs;
 366
 367                 for (ct_idx = 0; ct_idx < active; ct_idx++, ci_ptr++)
 368                         kvfree(ci_ptr->values);
 369
 370                 kfree(info->functions[fi_idx]);
 371         }
 372
 373 free_info:
 374         kfree(info->functions);
 375         kfree(info->filename);
 376         kfree(info);
 377 }
 378
 379 /**
 380  * convert_to_gcda - convert profiling data set to gcda file format
 381  * @buffer: the buffer to store file data or %NULL if no data should be stored
 382  * @info: profiling data set to be converted
 383  *
 384  * Returns the number of bytes that were/would have been stored into the buffer.
 385  */
 386 size_t convert_to_gcda(char *buffer, struct gcov_info *info)
 387 {
 388         struct gcov_fn_info *fi_ptr;
 389         struct gcov_ctr_info *ci_ptr;
 390         unsigned int fi_idx;
 391         unsigned int ct_idx;
 392         unsigned int cv_idx;
 393         size_t pos = 0;
 394
 395         /* File header. */
 396         pos += store_gcov_u32(buffer, pos, GCOV_DATA_MAGIC);
 397         pos += store_gcov_u32(buffer, pos, info->version);
 398         pos += store_gcov_u32(buffer, pos, info->stamp);
 399
 400 #if (__GNUC__ >= 12)
 401         /* Use zero as checksum of the compilation unit. */
 402         pos += store_gcov_u32(buffer, pos, 0);
 403 #endif
 404
 405         for (fi_idx = 0; fi_idx < info->n_functions; fi_idx++) {
 406                 fi_ptr = info->functions[fi_idx];
 407
 408                 /* Function record. */
 409                 pos += store_gcov_u32(buffer, pos, GCOV_TAG_FUNCTION);
 410                 pos += store_gcov_u32(buffer, pos,
 411                         GCOV_TAG_FUNCTION_LENGTH * GCOV_UNIT_SIZE);
 412                 pos += store_gcov_u32(buffer, pos, fi_ptr->ident);
 413                 pos += store_gcov_u32(buffer, pos, fi_ptr->lineno_checksum);
 414                 pos += store_gcov_u32(buffer, pos, fi_ptr->cfg_checksum);
 415
 416                 ci_ptr = fi_ptr->ctrs;
 417
 418                 for (ct_idx = 0; ct_idx < GCOV_COUNTERS; ct_idx++) {
 419                         if (!counter_active(info, ct_idx))
 420                                 continue;
 421
 422                         /* Counter record. */
 423                         pos += store_gcov_u32(buffer, pos,
 424                                               GCOV_TAG_FOR_COUNTER(ct_idx));
 425                         pos += store_gcov_u32(buffer, pos,
 426                                 ci_ptr->num * 2 * GCOV_UNIT_SIZE);
 427
 428                         for (cv_idx = 0; cv_idx < ci_ptr->num; cv_idx++) {
 429                                 pos += store_gcov_u64(buffer, pos,
 430                                                       ci_ptr->values[cv_idx]);
 431                         }
 432
 433                         ci_ptr++;
 434                 }
 435         }
 436
 437         return pos;
 438 }