Peter Oberparleiter | 2521f2c | 2009-06-17 16:28:08 -0700 | [diff] [blame] | 1 | /* |
| 2 | * This code exports profiling data as debugfs files to userspace. |
| 3 | * |
| 4 | * Copyright IBM Corp. 2009 |
| 5 | * Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com> |
| 6 | * |
| 7 | * Uses gcc-internal data definitions. |
| 8 | * Based on the gcov-kernel patch by: |
| 9 | * Hubertus Franke <frankeh@us.ibm.com> |
| 10 | * Nigel Hinds <nhinds@us.ibm.com> |
| 11 | * Rajan Ravindran <rajancr@us.ibm.com> |
| 12 | * Peter Oberparleiter <oberpar@linux.vnet.ibm.com> |
| 13 | * Paul Larson |
| 14 | * Yi CDL Yang |
| 15 | */ |
| 16 | |
| 17 | #define pr_fmt(fmt) "gcov: " fmt |
| 18 | |
| 19 | #include <linux/init.h> |
| 20 | #include <linux/module.h> |
| 21 | #include <linux/debugfs.h> |
| 22 | #include <linux/fs.h> |
| 23 | #include <linux/list.h> |
| 24 | #include <linux/string.h> |
| 25 | #include <linux/slab.h> |
| 26 | #include <linux/mutex.h> |
| 27 | #include <linux/seq_file.h> |
| 28 | #include "gcov.h" |
| 29 | |
| 30 | /** |
| 31 | * struct gcov_node - represents a debugfs entry |
| 32 | * @list: list head for child node list |
| 33 | * @children: child nodes |
| 34 | * @all: list head for list of all nodes |
| 35 | * @parent: parent node |
| 36 | * @info: associated profiling data structure if not a directory |
| 37 | * @ghost: when an object file containing profiling data is unloaded we keep a |
| 38 | * copy of the profiling data here to allow collecting coverage data |
| 39 | * for cleanup code. Such a node is called a "ghost". |
| 40 | * @dentry: main debugfs entry, either a directory or data file |
| 41 | * @links: associated symbolic links |
| 42 | * @name: data file basename |
| 43 | * |
| 44 | * struct gcov_node represents an entity within the gcov/ subdirectory |
| 45 | * of debugfs. There are directory and data file nodes. The latter represent |
| 46 | * the actual synthesized data file plus any associated symbolic links which |
| 47 | * are needed by the gcov tool to work correctly. |
| 48 | */ |
| 49 | struct gcov_node { |
| 50 | struct list_head list; |
| 51 | struct list_head children; |
| 52 | struct list_head all; |
| 53 | struct gcov_node *parent; |
| 54 | struct gcov_info *info; |
| 55 | struct gcov_info *ghost; |
| 56 | struct dentry *dentry; |
| 57 | struct dentry **links; |
| 58 | char name[0]; |
| 59 | }; |
| 60 | |
| 61 | static const char objtree[] = OBJTREE; |
| 62 | static const char srctree[] = SRCTREE; |
| 63 | static struct gcov_node root_node; |
| 64 | static struct dentry *reset_dentry; |
| 65 | static LIST_HEAD(all_head); |
| 66 | static DEFINE_MUTEX(node_lock); |
| 67 | |
| 68 | /* If non-zero, keep copies of profiling data for unloaded modules. */ |
| 69 | static int gcov_persist = 1; |
| 70 | |
| 71 | static int __init gcov_persist_setup(char *str) |
| 72 | { |
| 73 | unsigned long val; |
| 74 | |
| 75 | if (strict_strtoul(str, 0, &val)) { |
| 76 | pr_warning("invalid gcov_persist parameter '%s'\n", str); |
| 77 | return 0; |
| 78 | } |
| 79 | gcov_persist = val; |
| 80 | pr_info("setting gcov_persist to %d\n", gcov_persist); |
| 81 | |
| 82 | return 1; |
| 83 | } |
| 84 | __setup("gcov_persist=", gcov_persist_setup); |
| 85 | |
| 86 | /* |
| 87 | * seq_file.start() implementation for gcov data files. Note that the |
| 88 | * gcov_iterator interface is designed to be more restrictive than seq_file |
| 89 | * (no start from arbitrary position, etc.), to simplify the iterator |
| 90 | * implementation. |
| 91 | */ |
| 92 | static void *gcov_seq_start(struct seq_file *seq, loff_t *pos) |
| 93 | { |
| 94 | loff_t i; |
| 95 | |
| 96 | gcov_iter_start(seq->private); |
| 97 | for (i = 0; i < *pos; i++) { |
| 98 | if (gcov_iter_next(seq->private)) |
| 99 | return NULL; |
| 100 | } |
| 101 | return seq->private; |
| 102 | } |
| 103 | |
| 104 | /* seq_file.next() implementation for gcov data files. */ |
| 105 | static void *gcov_seq_next(struct seq_file *seq, void *data, loff_t *pos) |
| 106 | { |
| 107 | struct gcov_iterator *iter = data; |
| 108 | |
| 109 | if (gcov_iter_next(iter)) |
| 110 | return NULL; |
| 111 | (*pos)++; |
| 112 | |
| 113 | return iter; |
| 114 | } |
| 115 | |
| 116 | /* seq_file.show() implementation for gcov data files. */ |
| 117 | static int gcov_seq_show(struct seq_file *seq, void *data) |
| 118 | { |
| 119 | struct gcov_iterator *iter = data; |
| 120 | |
| 121 | if (gcov_iter_write(iter, seq)) |
| 122 | return -EINVAL; |
| 123 | return 0; |
| 124 | } |
| 125 | |
| 126 | static void gcov_seq_stop(struct seq_file *seq, void *data) |
| 127 | { |
| 128 | /* Unused. */ |
| 129 | } |
| 130 | |
| 131 | static const struct seq_operations gcov_seq_ops = { |
| 132 | .start = gcov_seq_start, |
| 133 | .next = gcov_seq_next, |
| 134 | .show = gcov_seq_show, |
| 135 | .stop = gcov_seq_stop, |
| 136 | }; |
| 137 | |
| 138 | /* |
| 139 | * Return the profiling data set for a given node. This can either be the |
| 140 | * original profiling data structure or a duplicate (also called "ghost") |
| 141 | * in case the associated object file has been unloaded. |
| 142 | */ |
| 143 | static struct gcov_info *get_node_info(struct gcov_node *node) |
| 144 | { |
| 145 | if (node->info) |
| 146 | return node->info; |
| 147 | |
| 148 | return node->ghost; |
| 149 | } |
| 150 | |
| 151 | /* |
| 152 | * open() implementation for gcov data files. Create a copy of the profiling |
| 153 | * data set and initialize the iterator and seq_file interface. |
| 154 | */ |
| 155 | static int gcov_seq_open(struct inode *inode, struct file *file) |
| 156 | { |
| 157 | struct gcov_node *node = inode->i_private; |
| 158 | struct gcov_iterator *iter; |
| 159 | struct seq_file *seq; |
| 160 | struct gcov_info *info; |
| 161 | int rc = -ENOMEM; |
| 162 | |
| 163 | mutex_lock(&node_lock); |
| 164 | /* |
| 165 | * Read from a profiling data copy to minimize reference tracking |
| 166 | * complexity and concurrent access. |
| 167 | */ |
| 168 | info = gcov_info_dup(get_node_info(node)); |
| 169 | if (!info) |
| 170 | goto out_unlock; |
| 171 | iter = gcov_iter_new(info); |
| 172 | if (!iter) |
| 173 | goto err_free_info; |
| 174 | rc = seq_open(file, &gcov_seq_ops); |
| 175 | if (rc) |
| 176 | goto err_free_iter_info; |
| 177 | seq = file->private_data; |
| 178 | seq->private = iter; |
| 179 | out_unlock: |
| 180 | mutex_unlock(&node_lock); |
| 181 | return rc; |
| 182 | |
| 183 | err_free_iter_info: |
| 184 | gcov_iter_free(iter); |
| 185 | err_free_info: |
| 186 | gcov_info_free(info); |
| 187 | goto out_unlock; |
| 188 | } |
| 189 | |
| 190 | /* |
| 191 | * release() implementation for gcov data files. Release resources allocated |
| 192 | * by open(). |
| 193 | */ |
| 194 | static int gcov_seq_release(struct inode *inode, struct file *file) |
| 195 | { |
| 196 | struct gcov_iterator *iter; |
| 197 | struct gcov_info *info; |
| 198 | struct seq_file *seq; |
| 199 | |
| 200 | seq = file->private_data; |
| 201 | iter = seq->private; |
| 202 | info = gcov_iter_get_info(iter); |
| 203 | gcov_iter_free(iter); |
| 204 | gcov_info_free(info); |
| 205 | seq_release(inode, file); |
| 206 | |
| 207 | return 0; |
| 208 | } |
| 209 | |
| 210 | /* |
| 211 | * Find a node by the associated data file name. Needs to be called with |
| 212 | * node_lock held. |
| 213 | */ |
| 214 | static struct gcov_node *get_node_by_name(const char *name) |
| 215 | { |
| 216 | struct gcov_node *node; |
| 217 | struct gcov_info *info; |
| 218 | |
| 219 | list_for_each_entry(node, &all_head, all) { |
| 220 | info = get_node_info(node); |
| 221 | if (info && (strcmp(info->filename, name) == 0)) |
| 222 | return node; |
| 223 | } |
| 224 | |
| 225 | return NULL; |
| 226 | } |
| 227 | |
| 228 | static void remove_node(struct gcov_node *node); |
| 229 | |
| 230 | /* |
| 231 | * write() implementation for gcov data files. Reset profiling data for the |
| 232 | * associated file. If the object file has been unloaded (i.e. this is |
| 233 | * a "ghost" node), remove the debug fs node as well. |
| 234 | */ |
| 235 | static ssize_t gcov_seq_write(struct file *file, const char __user *addr, |
| 236 | size_t len, loff_t *pos) |
| 237 | { |
| 238 | struct seq_file *seq; |
| 239 | struct gcov_info *info; |
| 240 | struct gcov_node *node; |
| 241 | |
| 242 | seq = file->private_data; |
| 243 | info = gcov_iter_get_info(seq->private); |
| 244 | mutex_lock(&node_lock); |
| 245 | node = get_node_by_name(info->filename); |
| 246 | if (node) { |
| 247 | /* Reset counts or remove node for unloaded modules. */ |
| 248 | if (node->ghost) |
| 249 | remove_node(node); |
| 250 | else |
| 251 | gcov_info_reset(node->info); |
| 252 | } |
| 253 | /* Reset counts for open file. */ |
| 254 | gcov_info_reset(info); |
| 255 | mutex_unlock(&node_lock); |
| 256 | |
| 257 | return len; |
| 258 | } |
| 259 | |
| 260 | /* |
| 261 | * Given a string <path> representing a file path of format: |
| 262 | * path/to/file.gcda |
| 263 | * construct and return a new string: |
| 264 | * <dir/>path/to/file.<ext> |
| 265 | */ |
| 266 | static char *link_target(const char *dir, const char *path, const char *ext) |
| 267 | { |
| 268 | char *target; |
| 269 | char *old_ext; |
| 270 | char *copy; |
| 271 | |
| 272 | copy = kstrdup(path, GFP_KERNEL); |
| 273 | if (!copy) |
| 274 | return NULL; |
| 275 | old_ext = strrchr(copy, '.'); |
| 276 | if (old_ext) |
| 277 | *old_ext = '\0'; |
| 278 | if (dir) |
| 279 | target = kasprintf(GFP_KERNEL, "%s/%s.%s", dir, copy, ext); |
| 280 | else |
| 281 | target = kasprintf(GFP_KERNEL, "%s.%s", copy, ext); |
| 282 | kfree(copy); |
| 283 | |
| 284 | return target; |
| 285 | } |
| 286 | |
| 287 | /* |
| 288 | * Construct a string representing the symbolic link target for the given |
| 289 | * gcov data file name and link type. Depending on the link type and the |
| 290 | * location of the data file, the link target can either point to a |
| 291 | * subdirectory of srctree, objtree or in an external location. |
| 292 | */ |
| 293 | static char *get_link_target(const char *filename, const struct gcov_link *ext) |
| 294 | { |
| 295 | const char *rel; |
| 296 | char *result; |
| 297 | |
| 298 | if (strncmp(filename, objtree, strlen(objtree)) == 0) { |
| 299 | rel = filename + strlen(objtree) + 1; |
| 300 | if (ext->dir == SRC_TREE) |
| 301 | result = link_target(srctree, rel, ext->ext); |
| 302 | else |
| 303 | result = link_target(objtree, rel, ext->ext); |
| 304 | } else { |
| 305 | /* External compilation. */ |
| 306 | result = link_target(NULL, filename, ext->ext); |
| 307 | } |
| 308 | |
| 309 | return result; |
| 310 | } |
| 311 | |
| 312 | #define SKEW_PREFIX ".tmp_" |
| 313 | |
| 314 | /* |
| 315 | * For a filename .tmp_filename.ext return filename.ext. Needed to compensate |
| 316 | * for filename skewing caused by the mod-versioning mechanism. |
| 317 | */ |
| 318 | static const char *deskew(const char *basename) |
| 319 | { |
| 320 | if (strncmp(basename, SKEW_PREFIX, sizeof(SKEW_PREFIX) - 1) == 0) |
| 321 | return basename + sizeof(SKEW_PREFIX) - 1; |
| 322 | return basename; |
| 323 | } |
| 324 | |
| 325 | /* |
| 326 | * Create links to additional files (usually .c and .gcno files) which the |
| 327 | * gcov tool expects to find in the same directory as the gcov data file. |
| 328 | */ |
| 329 | static void add_links(struct gcov_node *node, struct dentry *parent) |
| 330 | { |
| 331 | char *basename; |
| 332 | char *target; |
| 333 | int num; |
| 334 | int i; |
| 335 | |
| 336 | for (num = 0; gcov_link[num].ext; num++) |
| 337 | /* Nothing. */; |
| 338 | node->links = kcalloc(num, sizeof(struct dentry *), GFP_KERNEL); |
| 339 | if (!node->links) |
| 340 | return; |
| 341 | for (i = 0; i < num; i++) { |
| 342 | target = get_link_target(get_node_info(node)->filename, |
| 343 | &gcov_link[i]); |
| 344 | if (!target) |
| 345 | goto out_err; |
| 346 | basename = strrchr(target, '/'); |
| 347 | if (!basename) |
| 348 | goto out_err; |
| 349 | basename++; |
| 350 | node->links[i] = debugfs_create_symlink(deskew(basename), |
| 351 | parent, target); |
| 352 | if (!node->links[i]) |
| 353 | goto out_err; |
| 354 | kfree(target); |
| 355 | } |
| 356 | |
| 357 | return; |
| 358 | out_err: |
| 359 | kfree(target); |
| 360 | while (i-- > 0) |
| 361 | debugfs_remove(node->links[i]); |
| 362 | kfree(node->links); |
| 363 | node->links = NULL; |
| 364 | } |
| 365 | |
| 366 | static const struct file_operations gcov_data_fops = { |
| 367 | .open = gcov_seq_open, |
| 368 | .release = gcov_seq_release, |
| 369 | .read = seq_read, |
| 370 | .llseek = seq_lseek, |
| 371 | .write = gcov_seq_write, |
| 372 | }; |
| 373 | |
| 374 | /* Basic initialization of a new node. */ |
| 375 | static void init_node(struct gcov_node *node, struct gcov_info *info, |
| 376 | const char *name, struct gcov_node *parent) |
| 377 | { |
| 378 | INIT_LIST_HEAD(&node->list); |
| 379 | INIT_LIST_HEAD(&node->children); |
| 380 | INIT_LIST_HEAD(&node->all); |
| 381 | node->info = info; |
| 382 | node->parent = parent; |
| 383 | if (name) |
| 384 | strcpy(node->name, name); |
| 385 | } |
| 386 | |
| 387 | /* |
| 388 | * Create a new node and associated debugfs entry. Needs to be called with |
| 389 | * node_lock held. |
| 390 | */ |
| 391 | static struct gcov_node *new_node(struct gcov_node *parent, |
| 392 | struct gcov_info *info, const char *name) |
| 393 | { |
| 394 | struct gcov_node *node; |
| 395 | |
| 396 | node = kzalloc(sizeof(struct gcov_node) + strlen(name) + 1, GFP_KERNEL); |
| 397 | if (!node) { |
| 398 | pr_warning("out of memory\n"); |
| 399 | return NULL; |
| 400 | } |
| 401 | init_node(node, info, name, parent); |
| 402 | /* Differentiate between gcov data file nodes and directory nodes. */ |
| 403 | if (info) { |
| 404 | node->dentry = debugfs_create_file(deskew(node->name), 0600, |
| 405 | parent->dentry, node, &gcov_data_fops); |
| 406 | } else |
| 407 | node->dentry = debugfs_create_dir(node->name, parent->dentry); |
| 408 | if (!node->dentry) { |
| 409 | pr_warning("could not create file\n"); |
| 410 | kfree(node); |
| 411 | return NULL; |
| 412 | } |
| 413 | if (info) |
| 414 | add_links(node, parent->dentry); |
| 415 | list_add(&node->list, &parent->children); |
| 416 | list_add(&node->all, &all_head); |
| 417 | |
| 418 | return node; |
| 419 | } |
| 420 | |
| 421 | /* Remove symbolic links associated with node. */ |
| 422 | static void remove_links(struct gcov_node *node) |
| 423 | { |
| 424 | int i; |
| 425 | |
| 426 | if (!node->links) |
| 427 | return; |
| 428 | for (i = 0; gcov_link[i].ext; i++) |
| 429 | debugfs_remove(node->links[i]); |
| 430 | kfree(node->links); |
| 431 | node->links = NULL; |
| 432 | } |
| 433 | |
| 434 | /* |
| 435 | * Remove node from all lists and debugfs and release associated resources. |
| 436 | * Needs to be called with node_lock held. |
| 437 | */ |
| 438 | static void release_node(struct gcov_node *node) |
| 439 | { |
| 440 | list_del(&node->list); |
| 441 | list_del(&node->all); |
| 442 | debugfs_remove(node->dentry); |
| 443 | remove_links(node); |
| 444 | if (node->ghost) |
| 445 | gcov_info_free(node->ghost); |
| 446 | kfree(node); |
| 447 | } |
| 448 | |
| 449 | /* Release node and empty parents. Needs to be called with node_lock held. */ |
| 450 | static void remove_node(struct gcov_node *node) |
| 451 | { |
| 452 | struct gcov_node *parent; |
| 453 | |
| 454 | while ((node != &root_node) && list_empty(&node->children)) { |
| 455 | parent = node->parent; |
| 456 | release_node(node); |
| 457 | node = parent; |
| 458 | } |
| 459 | } |
| 460 | |
| 461 | /* |
| 462 | * Find child node with given basename. Needs to be called with node_lock |
| 463 | * held. |
| 464 | */ |
| 465 | static struct gcov_node *get_child_by_name(struct gcov_node *parent, |
| 466 | const char *name) |
| 467 | { |
| 468 | struct gcov_node *node; |
| 469 | |
| 470 | list_for_each_entry(node, &parent->children, list) { |
| 471 | if (strcmp(node->name, name) == 0) |
| 472 | return node; |
| 473 | } |
| 474 | |
| 475 | return NULL; |
| 476 | } |
| 477 | |
| 478 | /* |
| 479 | * write() implementation for reset file. Reset all profiling data to zero |
| 480 | * and remove ghost nodes. |
| 481 | */ |
| 482 | static ssize_t reset_write(struct file *file, const char __user *addr, |
| 483 | size_t len, loff_t *pos) |
| 484 | { |
| 485 | struct gcov_node *node; |
| 486 | |
| 487 | mutex_lock(&node_lock); |
| 488 | restart: |
| 489 | list_for_each_entry(node, &all_head, all) { |
| 490 | if (node->info) |
| 491 | gcov_info_reset(node->info); |
| 492 | else if (list_empty(&node->children)) { |
| 493 | remove_node(node); |
| 494 | /* Several nodes may have gone - restart loop. */ |
| 495 | goto restart; |
| 496 | } |
| 497 | } |
| 498 | mutex_unlock(&node_lock); |
| 499 | |
| 500 | return len; |
| 501 | } |
| 502 | |
| 503 | /* read() implementation for reset file. Unused. */ |
| 504 | static ssize_t reset_read(struct file *file, char __user *addr, size_t len, |
| 505 | loff_t *pos) |
| 506 | { |
| 507 | /* Allow read operation so that a recursive copy won't fail. */ |
| 508 | return 0; |
| 509 | } |
| 510 | |
| 511 | static const struct file_operations gcov_reset_fops = { |
| 512 | .write = reset_write, |
| 513 | .read = reset_read, |
| 514 | }; |
| 515 | |
| 516 | /* |
| 517 | * Create a node for a given profiling data set and add it to all lists and |
| 518 | * debugfs. Needs to be called with node_lock held. |
| 519 | */ |
| 520 | static void add_node(struct gcov_info *info) |
| 521 | { |
| 522 | char *filename; |
| 523 | char *curr; |
| 524 | char *next; |
| 525 | struct gcov_node *parent; |
| 526 | struct gcov_node *node; |
| 527 | |
| 528 | filename = kstrdup(info->filename, GFP_KERNEL); |
| 529 | if (!filename) |
| 530 | return; |
| 531 | parent = &root_node; |
| 532 | /* Create directory nodes along the path. */ |
| 533 | for (curr = filename; (next = strchr(curr, '/')); curr = next + 1) { |
| 534 | if (curr == next) |
| 535 | continue; |
| 536 | *next = 0; |
| 537 | if (strcmp(curr, ".") == 0) |
| 538 | continue; |
| 539 | if (strcmp(curr, "..") == 0) { |
| 540 | if (!parent->parent) |
| 541 | goto err_remove; |
| 542 | parent = parent->parent; |
| 543 | continue; |
| 544 | } |
| 545 | node = get_child_by_name(parent, curr); |
| 546 | if (!node) { |
| 547 | node = new_node(parent, NULL, curr); |
| 548 | if (!node) |
| 549 | goto err_remove; |
| 550 | } |
| 551 | parent = node; |
| 552 | } |
| 553 | /* Create file node. */ |
| 554 | node = new_node(parent, info, curr); |
| 555 | if (!node) |
| 556 | goto err_remove; |
| 557 | out: |
| 558 | kfree(filename); |
| 559 | return; |
| 560 | |
| 561 | err_remove: |
| 562 | remove_node(parent); |
| 563 | goto out; |
| 564 | } |
| 565 | |
| 566 | /* |
| 567 | * The profiling data set associated with this node is being unloaded. Store a |
| 568 | * copy of the profiling data and turn this node into a "ghost". |
| 569 | */ |
| 570 | static int ghost_node(struct gcov_node *node) |
| 571 | { |
| 572 | node->ghost = gcov_info_dup(node->info); |
| 573 | if (!node->ghost) { |
| 574 | pr_warning("could not save data for '%s' (out of memory)\n", |
| 575 | node->info->filename); |
| 576 | return -ENOMEM; |
| 577 | } |
| 578 | node->info = NULL; |
| 579 | |
| 580 | return 0; |
| 581 | } |
| 582 | |
| 583 | /* |
| 584 | * Profiling data for this node has been loaded again. Add profiling data |
| 585 | * from previous instantiation and turn this node into a regular node. |
| 586 | */ |
| 587 | static void revive_node(struct gcov_node *node, struct gcov_info *info) |
| 588 | { |
| 589 | if (gcov_info_is_compatible(node->ghost, info)) |
| 590 | gcov_info_add(info, node->ghost); |
| 591 | else { |
| 592 | pr_warning("discarding saved data for '%s' (version changed)\n", |
| 593 | info->filename); |
| 594 | } |
| 595 | gcov_info_free(node->ghost); |
| 596 | node->ghost = NULL; |
| 597 | node->info = info; |
| 598 | } |
| 599 | |
| 600 | /* |
| 601 | * Callback to create/remove profiling files when code compiled with |
| 602 | * -fprofile-arcs is loaded/unloaded. |
| 603 | */ |
| 604 | void gcov_event(enum gcov_action action, struct gcov_info *info) |
| 605 | { |
| 606 | struct gcov_node *node; |
| 607 | |
| 608 | mutex_lock(&node_lock); |
| 609 | node = get_node_by_name(info->filename); |
| 610 | switch (action) { |
| 611 | case GCOV_ADD: |
| 612 | /* Add new node or revive ghost. */ |
| 613 | if (!node) { |
| 614 | add_node(info); |
| 615 | break; |
| 616 | } |
| 617 | if (gcov_persist) |
| 618 | revive_node(node, info); |
| 619 | else { |
| 620 | pr_warning("could not add '%s' (already exists)\n", |
| 621 | info->filename); |
| 622 | } |
| 623 | break; |
| 624 | case GCOV_REMOVE: |
| 625 | /* Remove node or turn into ghost. */ |
| 626 | if (!node) { |
| 627 | pr_warning("could not remove '%s' (not found)\n", |
| 628 | info->filename); |
| 629 | break; |
| 630 | } |
| 631 | if (gcov_persist) { |
| 632 | if (!ghost_node(node)) |
| 633 | break; |
| 634 | } |
| 635 | remove_node(node); |
| 636 | break; |
| 637 | } |
| 638 | mutex_unlock(&node_lock); |
| 639 | } |
| 640 | |
| 641 | /* Create debugfs entries. */ |
| 642 | static __init int gcov_fs_init(void) |
| 643 | { |
| 644 | int rc = -EIO; |
| 645 | |
| 646 | init_node(&root_node, NULL, NULL, NULL); |
| 647 | /* |
| 648 | * /sys/kernel/debug/gcov will be parent for the reset control file |
| 649 | * and all profiling files. |
| 650 | */ |
| 651 | root_node.dentry = debugfs_create_dir("gcov", NULL); |
| 652 | if (!root_node.dentry) |
| 653 | goto err_remove; |
| 654 | /* |
| 655 | * Create reset file which resets all profiling counts when written |
| 656 | * to. |
| 657 | */ |
| 658 | reset_dentry = debugfs_create_file("reset", 0600, root_node.dentry, |
| 659 | NULL, &gcov_reset_fops); |
| 660 | if (!reset_dentry) |
| 661 | goto err_remove; |
| 662 | /* Replay previous events to get our fs hierarchy up-to-date. */ |
| 663 | gcov_enable_events(); |
| 664 | return 0; |
| 665 | |
| 666 | err_remove: |
| 667 | pr_err("init failed\n"); |
| 668 | if (root_node.dentry) |
| 669 | debugfs_remove(root_node.dentry); |
| 670 | |
| 671 | return rc; |
| 672 | } |
| 673 | device_initcall(gcov_fs_init); |