Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * This code exports profiling data as debugfs files to userspace.
4 : *
5 : * Copyright IBM Corp. 2009
6 : * Author(s): Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
7 : *
8 : * Uses gcc-internal data definitions.
9 : * Based on the gcov-kernel patch by:
10 : * Hubertus Franke <frankeh@us.ibm.com>
11 : * Nigel Hinds <nhinds@us.ibm.com>
12 : * Rajan Ravindran <rajancr@us.ibm.com>
13 : * Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
14 : * Paul Larson
15 : * Yi CDL Yang
16 : */
17 :
18 : #define pr_fmt(fmt) "gcov: " fmt
19 :
20 : #include <linux/init.h>
21 : #include <linux/module.h>
22 : #include <linux/debugfs.h>
23 : #include <linux/fs.h>
24 : #include <linux/list.h>
25 : #include <linux/string.h>
26 : #include <linux/slab.h>
27 : #include <linux/mutex.h>
28 : #include <linux/seq_file.h>
29 : #include "gcov.h"
30 :
31 : /**
32 : * struct gcov_node - represents a debugfs entry
33 : * @list: list head for child node list
34 : * @children: child nodes
35 : * @all: list head for list of all nodes
36 : * @parent: parent node
37 : * @loaded_info: array of pointers to profiling data sets for loaded object
38 : * files.
39 : * @num_loaded: number of profiling data sets for loaded object files.
40 : * @unloaded_info: accumulated copy of profiling data sets for unloaded
41 : * object files. Used only when gcov_persist=1.
42 : * @dentry: main debugfs entry, either a directory or data file
43 : * @links: associated symbolic links
44 : * @name: data file basename
45 : *
46 : * struct gcov_node represents an entity within the gcov/ subdirectory
47 : * of debugfs. There are directory and data file nodes. The latter represent
48 : * the actual synthesized data file plus any associated symbolic links which
49 : * are needed by the gcov tool to work correctly.
50 : */
51 : struct gcov_node {
52 : struct list_head list;
53 : struct list_head children;
54 : struct list_head all;
55 : struct gcov_node *parent;
56 : struct gcov_info **loaded_info;
57 : struct gcov_info *unloaded_info;
58 : struct dentry *dentry;
59 : struct dentry **links;
60 : int num_loaded;
61 : char name[];
62 : };
63 :
64 : static const char objtree[] = OBJTREE;
65 : static const char srctree[] = SRCTREE;
66 : static struct gcov_node root_node;
67 : static LIST_HEAD(all_head);
68 : static DEFINE_MUTEX(node_lock);
69 :
70 : /* If non-zero, keep copies of profiling data for unloaded modules. */
71 : static int gcov_persist = 1;
72 :
73 0 : static int __init gcov_persist_setup(char *str)
74 : {
75 0 : unsigned long val;
76 :
77 0 : if (kstrtoul(str, 0, &val)) {
78 0 : pr_warn("invalid gcov_persist parameter '%s'\n", str);
79 0 : return 0;
80 : }
81 0 : gcov_persist = val;
82 0 : pr_info("setting gcov_persist to %d\n", gcov_persist);
83 :
84 0 : return 1;
85 : }
86 : __setup("gcov_persist=", gcov_persist_setup);
87 :
88 : /*
89 : * seq_file.start() implementation for gcov data files. Note that the
90 : * gcov_iterator interface is designed to be more restrictive than seq_file
91 : * (no start from arbitrary position, etc.), to simplify the iterator
92 : * implementation.
93 : */
94 356 : static void *gcov_seq_start(struct seq_file *seq, loff_t *pos)
95 : {
96 356 : loff_t i;
97 :
98 356 : gcov_iter_start(seq->private);
99 917 : for (i = 0; i < *pos; i++) {
100 339 : if (gcov_iter_next(seq->private))
101 : return NULL;
102 : }
103 222 : return seq->private;
104 : }
105 :
106 : /* seq_file.next() implementation for gcov data files. */
107 222 : static void *gcov_seq_next(struct seq_file *seq, void *data, loff_t *pos)
108 : {
109 222 : struct gcov_iterator *iter = data;
110 :
111 222 : (*pos)++;
112 222 : if (gcov_iter_next(iter))
113 134 : return NULL;
114 :
115 : return iter;
116 : }
117 :
118 : /* seq_file.show() implementation for gcov data files. */
119 310 : static int gcov_seq_show(struct seq_file *seq, void *data)
120 : {
121 310 : struct gcov_iterator *iter = data;
122 :
123 310 : if (gcov_iter_write(iter, seq))
124 0 : return -EINVAL;
125 : return 0;
126 : }
127 :
128 356 : static void gcov_seq_stop(struct seq_file *seq, void *data)
129 : {
130 : /* Unused. */
131 356 : }
132 :
133 : static const struct seq_operations gcov_seq_ops = {
134 : .start = gcov_seq_start,
135 : .next = gcov_seq_next,
136 : .show = gcov_seq_show,
137 : .stop = gcov_seq_stop,
138 : };
139 :
140 : /*
141 : * Return a profiling data set associated with the given node. This is
142 : * either a data set for a loaded object file or a data set copy in case
143 : * all associated object files have been unloaded.
144 : */
145 511981 : static struct gcov_info *get_node_info(struct gcov_node *node)
146 : {
147 511981 : if (node->num_loaded > 0)
148 456490 : return node->loaded_info[0];
149 :
150 55491 : return node->unloaded_info;
151 : }
152 :
153 : /*
154 : * Return a newly allocated profiling data set which contains the sum of
155 : * all profiling data associated with the given node.
156 : */
157 135 : static struct gcov_info *get_accumulated_info(struct gcov_node *node)
158 : {
159 135 : struct gcov_info *info;
160 135 : int i = 0;
161 :
162 135 : if (node->unloaded_info)
163 0 : info = gcov_info_dup(node->unloaded_info);
164 : else
165 135 : info = gcov_info_dup(node->loaded_info[i++]);
166 134 : if (!info)
167 : return NULL;
168 134 : for (; i < node->num_loaded; i++)
169 0 : gcov_info_add(info, node->loaded_info[i]);
170 :
171 : return info;
172 : }
173 :
174 : /*
175 : * open() implementation for gcov data files. Create a copy of the profiling
176 : * data set and initialize the iterator and seq_file interface.
177 : */
178 135 : static int gcov_seq_open(struct inode *inode, struct file *file)
179 : {
180 135 : struct gcov_node *node = inode->i_private;
181 135 : struct gcov_iterator *iter;
182 135 : struct seq_file *seq;
183 135 : struct gcov_info *info;
184 135 : int rc = -ENOMEM;
185 :
186 135 : mutex_lock(&node_lock);
187 : /*
188 : * Read from a profiling data copy to minimize reference tracking
189 : * complexity and concurrent access and to keep accumulating multiple
190 : * profiling data sets associated with one node simple.
191 : */
192 135 : info = get_accumulated_info(node);
193 134 : if (!info)
194 0 : goto out_unlock;
195 134 : iter = gcov_iter_new(info);
196 134 : if (!iter)
197 0 : goto err_free_info;
198 134 : rc = seq_open(file, &gcov_seq_ops);
199 134 : if (rc)
200 0 : goto err_free_iter_info;
201 134 : seq = file->private_data;
202 134 : seq->private = iter;
203 134 : out_unlock:
204 134 : mutex_unlock(&node_lock);
205 134 : return rc;
206 :
207 0 : err_free_iter_info:
208 0 : gcov_iter_free(iter);
209 0 : err_free_info:
210 0 : gcov_info_free(info);
211 0 : goto out_unlock;
212 : }
213 :
214 : /*
215 : * release() implementation for gcov data files. Release resources allocated
216 : * by open().
217 : */
218 134 : static int gcov_seq_release(struct inode *inode, struct file *file)
219 : {
220 134 : struct gcov_iterator *iter;
221 134 : struct gcov_info *info;
222 134 : struct seq_file *seq;
223 :
224 134 : seq = file->private_data;
225 134 : iter = seq->private;
226 134 : info = gcov_iter_get_info(iter);
227 134 : gcov_iter_free(iter);
228 134 : gcov_info_free(info);
229 134 : seq_release(inode, file);
230 :
231 134 : return 0;
232 : }
233 :
234 : /*
235 : * Find a node by the associated data file name. Needs to be called with
236 : * node_lock held.
237 : */
238 955 : static struct gcov_node *get_node_by_name(const char *name)
239 : {
240 955 : struct gcov_node *node;
241 955 : struct gcov_info *info;
242 :
243 511981 : list_for_each_entry(node, &all_head, all) {
244 511026 : info = get_node_info(node);
245 511026 : if (info && (strcmp(gcov_info_filename(info), name) == 0))
246 0 : return node;
247 : }
248 :
249 : return NULL;
250 : }
251 :
252 : /*
253 : * Reset all profiling data associated with the specified node.
254 : */
255 0 : static void reset_node(struct gcov_node *node)
256 : {
257 0 : int i;
258 :
259 0 : if (node->unloaded_info)
260 0 : gcov_info_reset(node->unloaded_info);
261 0 : for (i = 0; i < node->num_loaded; i++)
262 0 : gcov_info_reset(node->loaded_info[i]);
263 0 : }
264 :
265 : static void remove_node(struct gcov_node *node);
266 :
267 : /*
268 : * write() implementation for gcov data files. Reset profiling data for the
269 : * corresponding file. If all associated object files have been unloaded,
270 : * remove the debug fs node as well.
271 : */
272 0 : static ssize_t gcov_seq_write(struct file *file, const char __user *addr,
273 : size_t len, loff_t *pos)
274 : {
275 0 : struct seq_file *seq;
276 0 : struct gcov_info *info;
277 0 : struct gcov_node *node;
278 :
279 0 : seq = file->private_data;
280 0 : info = gcov_iter_get_info(seq->private);
281 0 : mutex_lock(&node_lock);
282 0 : node = get_node_by_name(gcov_info_filename(info));
283 0 : if (node) {
284 : /* Reset counts or remove node for unloaded modules. */
285 0 : if (node->num_loaded == 0)
286 0 : remove_node(node);
287 : else
288 0 : reset_node(node);
289 : }
290 : /* Reset counts for open file. */
291 0 : gcov_info_reset(info);
292 0 : mutex_unlock(&node_lock);
293 :
294 0 : return len;
295 : }
296 :
297 : /*
298 : * Given a string <path> representing a file path of format:
299 : * path/to/file.gcda
300 : * construct and return a new string:
301 : * <dir/>path/to/file.<ext>
302 : */
303 955 : static char *link_target(const char *dir, const char *path, const char *ext)
304 : {
305 955 : char *target;
306 955 : char *old_ext;
307 955 : char *copy;
308 :
309 955 : copy = kstrdup(path, GFP_KERNEL);
310 955 : if (!copy)
311 : return NULL;
312 955 : old_ext = strrchr(copy, '.');
313 955 : if (old_ext)
314 955 : *old_ext = '\0';
315 955 : if (dir)
316 0 : target = kasprintf(GFP_KERNEL, "%s/%s.%s", dir, copy, ext);
317 : else
318 955 : target = kasprintf(GFP_KERNEL, "%s.%s", copy, ext);
319 955 : kfree(copy);
320 :
321 955 : return target;
322 : }
323 :
324 : /*
325 : * Construct a string representing the symbolic link target for the given
326 : * gcov data file name and link type. Depending on the link type and the
327 : * location of the data file, the link target can either point to a
328 : * subdirectory of srctree, objtree or in an external location.
329 : */
330 955 : static char *get_link_target(const char *filename, const struct gcov_link *ext)
331 : {
332 955 : const char *rel;
333 955 : char *result;
334 :
335 955 : if (strncmp(filename, objtree, strlen(objtree)) == 0) {
336 0 : rel = filename + strlen(objtree) + 1;
337 0 : if (ext->dir == SRC_TREE)
338 0 : result = link_target(srctree, rel, ext->ext);
339 : else
340 0 : result = link_target(objtree, rel, ext->ext);
341 : } else {
342 : /* External compilation. */
343 955 : result = link_target(NULL, filename, ext->ext);
344 : }
345 :
346 955 : return result;
347 : }
348 :
349 : #define SKEW_PREFIX ".tmp_"
350 :
351 : /*
352 : * For a filename .tmp_filename.ext return filename.ext. Needed to compensate
353 : * for filename skewing caused by the mod-versioning mechanism.
354 : */
355 1910 : static const char *deskew(const char *basename)
356 : {
357 1910 : if (strncmp(basename, SKEW_PREFIX, sizeof(SKEW_PREFIX) - 1) == 0)
358 0 : return basename + sizeof(SKEW_PREFIX) - 1;
359 : return basename;
360 : }
361 :
362 : /*
363 : * Create links to additional files (usually .c and .gcno files) which the
364 : * gcov tool expects to find in the same directory as the gcov data file.
365 : */
366 955 : static void add_links(struct gcov_node *node, struct dentry *parent)
367 : {
368 955 : const char *basename;
369 955 : char *target;
370 955 : int num;
371 955 : int i;
372 :
373 1910 : for (num = 0; gcov_link[num].ext; num++)
374 955 : /* Nothing. */;
375 955 : node->links = kcalloc(num, sizeof(struct dentry *), GFP_KERNEL);
376 955 : if (!node->links)
377 : return;
378 1910 : for (i = 0; i < num; i++) {
379 1910 : target = get_link_target(
380 : gcov_info_filename(get_node_info(node)),
381 : &gcov_link[i]);
382 955 : if (!target)
383 0 : goto out_err;
384 955 : basename = kbasename(target);
385 955 : if (basename == target)
386 0 : goto out_err;
387 955 : node->links[i] = debugfs_create_symlink(deskew(basename),
388 : parent, target);
389 955 : kfree(target);
390 : }
391 :
392 : return;
393 0 : out_err:
394 0 : kfree(target);
395 0 : while (i-- > 0)
396 0 : debugfs_remove(node->links[i]);
397 0 : kfree(node->links);
398 0 : node->links = NULL;
399 : }
400 :
401 : static const struct file_operations gcov_data_fops = {
402 : .open = gcov_seq_open,
403 : .release = gcov_seq_release,
404 : .read = seq_read,
405 : .llseek = seq_lseek,
406 : .write = gcov_seq_write,
407 : };
408 :
409 : /* Basic initialization of a new node. */
410 1058 : static void init_node(struct gcov_node *node, struct gcov_info *info,
411 : const char *name, struct gcov_node *parent)
412 : {
413 1057 : INIT_LIST_HEAD(&node->list);
414 1058 : INIT_LIST_HEAD(&node->children);
415 1058 : INIT_LIST_HEAD(&node->all);
416 1058 : if (node->loaded_info) {
417 955 : node->loaded_info[0] = info;
418 955 : node->num_loaded = 1;
419 : }
420 1058 : node->parent = parent;
421 1057 : if (name)
422 1057 : strcpy(node->name, name);
423 1057 : }
424 :
425 : /*
426 : * Create a new node and associated debugfs entry. Needs to be called with
427 : * node_lock held.
428 : */
429 1057 : static struct gcov_node *new_node(struct gcov_node *parent,
430 : struct gcov_info *info, const char *name)
431 : {
432 1057 : struct gcov_node *node;
433 :
434 1057 : node = kzalloc(sizeof(struct gcov_node) + strlen(name) + 1, GFP_KERNEL);
435 1057 : if (!node)
436 0 : goto err_nomem;
437 1057 : if (info) {
438 955 : node->loaded_info = kcalloc(1, sizeof(struct gcov_info *),
439 : GFP_KERNEL);
440 955 : if (!node->loaded_info)
441 0 : goto err_nomem;
442 : }
443 1057 : init_node(node, info, name, parent);
444 : /* Differentiate between gcov data file nodes and directory nodes. */
445 1057 : if (info) {
446 955 : node->dentry = debugfs_create_file(deskew(node->name), 0600,
447 : parent->dentry, node, &gcov_data_fops);
448 : } else
449 102 : node->dentry = debugfs_create_dir(node->name, parent->dentry);
450 1057 : if (info)
451 955 : add_links(node, parent->dentry);
452 1057 : list_add(&node->list, &parent->children);
453 1057 : list_add(&node->all, &all_head);
454 :
455 1057 : return node;
456 :
457 0 : err_nomem:
458 0 : kfree(node);
459 0 : pr_warn("out of memory\n");
460 0 : return NULL;
461 : }
462 :
463 : /* Remove symbolic links associated with node. */
464 0 : static void remove_links(struct gcov_node *node)
465 : {
466 0 : int i;
467 :
468 0 : if (!node->links)
469 : return;
470 0 : for (i = 0; gcov_link[i].ext; i++)
471 0 : debugfs_remove(node->links[i]);
472 0 : kfree(node->links);
473 0 : node->links = NULL;
474 : }
475 :
476 : /*
477 : * Remove node from all lists and debugfs and release associated resources.
478 : * Needs to be called with node_lock held.
479 : */
480 0 : static void release_node(struct gcov_node *node)
481 : {
482 0 : list_del(&node->list);
483 0 : list_del(&node->all);
484 0 : debugfs_remove(node->dentry);
485 0 : remove_links(node);
486 0 : kfree(node->loaded_info);
487 0 : if (node->unloaded_info)
488 0 : gcov_info_free(node->unloaded_info);
489 0 : kfree(node);
490 0 : }
491 :
492 : /* Release node and empty parents. Needs to be called with node_lock held. */
493 0 : static void remove_node(struct gcov_node *node)
494 : {
495 0 : struct gcov_node *parent;
496 :
497 0 : while ((node != &root_node) && list_empty(&node->children)) {
498 0 : parent = node->parent;
499 0 : release_node(node);
500 0 : node = parent;
501 : }
502 0 : }
503 :
504 : /*
505 : * Find child node with given basename. Needs to be called with node_lock
506 : * held.
507 : */
508 6617 : static struct gcov_node *get_child_by_name(struct gcov_node *parent,
509 : const char *name)
510 : {
511 6617 : struct gcov_node *node;
512 :
513 9080 : list_for_each_entry(node, &parent->children, list) {
514 8978 : if (strcmp(node->name, name) == 0)
515 6515 : return node;
516 : }
517 :
518 : return NULL;
519 : }
520 :
521 : /*
522 : * write() implementation for reset file. Reset all profiling data to zero
523 : * and remove nodes for which all associated object files are unloaded.
524 : */
525 0 : static ssize_t reset_write(struct file *file, const char __user *addr,
526 : size_t len, loff_t *pos)
527 : {
528 0 : struct gcov_node *node;
529 :
530 0 : mutex_lock(&node_lock);
531 0 : restart:
532 0 : list_for_each_entry(node, &all_head, all) {
533 0 : if (node->num_loaded > 0)
534 0 : reset_node(node);
535 0 : else if (list_empty(&node->children)) {
536 0 : remove_node(node);
537 : /* Several nodes may have gone - restart loop. */
538 0 : goto restart;
539 : }
540 : }
541 0 : mutex_unlock(&node_lock);
542 :
543 0 : return len;
544 : }
545 :
546 : /* read() implementation for reset file. Unused. */
547 0 : static ssize_t reset_read(struct file *file, char __user *addr, size_t len,
548 : loff_t *pos)
549 : {
550 : /* Allow read operation so that a recursive copy won't fail. */
551 0 : return 0;
552 : }
553 :
554 : static const struct file_operations gcov_reset_fops = {
555 : .write = reset_write,
556 : .read = reset_read,
557 : .llseek = noop_llseek,
558 : };
559 :
560 : /*
561 : * Create a node for a given profiling data set and add it to all lists and
562 : * debugfs. Needs to be called with node_lock held.
563 : */
564 955 : static void add_node(struct gcov_info *info)
565 : {
566 955 : char *filename;
567 955 : char *curr;
568 955 : char *next;
569 955 : struct gcov_node *parent;
570 955 : struct gcov_node *node;
571 :
572 955 : filename = kstrdup(gcov_info_filename(info), GFP_KERNEL);
573 955 : if (!filename)
574 : return;
575 : parent = &root_node;
576 : /* Create directory nodes along the path. */
577 8527 : for (curr = filename; (next = strchr(curr, '/')); curr = next + 1) {
578 7572 : if (curr == next)
579 955 : continue;
580 6617 : *next = 0;
581 6617 : if (strcmp(curr, ".") == 0)
582 0 : continue;
583 6617 : if (strcmp(curr, "..") == 0) {
584 0 : if (!parent->parent)
585 0 : goto err_remove;
586 0 : parent = parent->parent;
587 0 : continue;
588 : }
589 6617 : node = get_child_by_name(parent, curr);
590 6617 : if (!node) {
591 102 : node = new_node(parent, NULL, curr);
592 102 : if (!node)
593 0 : goto err_remove;
594 : }
595 : parent = node;
596 : }
597 : /* Create file node. */
598 955 : node = new_node(parent, info, curr);
599 955 : if (!node)
600 0 : goto err_remove;
601 955 : out:
602 955 : kfree(filename);
603 955 : return;
604 :
605 0 : err_remove:
606 0 : remove_node(parent);
607 0 : goto out;
608 : }
609 :
610 : /*
611 : * Associate a profiling data set with an existing node. Needs to be called
612 : * with node_lock held.
613 : */
614 0 : static void add_info(struct gcov_node *node, struct gcov_info *info)
615 : {
616 0 : struct gcov_info **loaded_info;
617 0 : int num = node->num_loaded;
618 :
619 : /*
620 : * Prepare new array. This is done first to simplify cleanup in
621 : * case the new data set is incompatible, the node only contains
622 : * unloaded data sets and there's not enough memory for the array.
623 : */
624 0 : loaded_info = kcalloc(num + 1, sizeof(struct gcov_info *), GFP_KERNEL);
625 0 : if (!loaded_info) {
626 0 : pr_warn("could not add '%s' (out of memory)\n",
627 : gcov_info_filename(info));
628 0 : return;
629 : }
630 0 : memcpy(loaded_info, node->loaded_info,
631 : num * sizeof(struct gcov_info *));
632 0 : loaded_info[num] = info;
633 : /* Check if the new data set is compatible. */
634 0 : if (num == 0) {
635 : /*
636 : * A module was unloaded, modified and reloaded. The new
637 : * data set replaces the copy of the last one.
638 : */
639 0 : if (!gcov_info_is_compatible(node->unloaded_info, info)) {
640 0 : pr_warn("discarding saved data for %s "
641 : "(incompatible version)\n",
642 : gcov_info_filename(info));
643 0 : gcov_info_free(node->unloaded_info);
644 0 : node->unloaded_info = NULL;
645 : }
646 : } else {
647 : /*
648 : * Two different versions of the same object file are loaded.
649 : * The initial one takes precedence.
650 : */
651 0 : if (!gcov_info_is_compatible(node->loaded_info[0], info)) {
652 0 : pr_warn("could not add '%s' (incompatible "
653 : "version)\n", gcov_info_filename(info));
654 0 : kfree(loaded_info);
655 0 : return;
656 : }
657 : }
658 : /* Overwrite previous array. */
659 0 : kfree(node->loaded_info);
660 0 : node->loaded_info = loaded_info;
661 0 : node->num_loaded = num + 1;
662 : }
663 :
664 : /*
665 : * Return the index of a profiling data set associated with a node.
666 : */
667 0 : static int get_info_index(struct gcov_node *node, struct gcov_info *info)
668 : {
669 0 : int i;
670 :
671 0 : for (i = 0; i < node->num_loaded; i++) {
672 0 : if (node->loaded_info[i] == info)
673 : return i;
674 : }
675 : return -ENOENT;
676 : }
677 :
678 : /*
679 : * Save the data of a profiling data set which is being unloaded.
680 : */
681 0 : static void save_info(struct gcov_node *node, struct gcov_info *info)
682 : {
683 0 : if (node->unloaded_info)
684 0 : gcov_info_add(node->unloaded_info, info);
685 : else {
686 0 : node->unloaded_info = gcov_info_dup(info);
687 0 : if (!node->unloaded_info) {
688 0 : pr_warn("could not save data for '%s' "
689 : "(out of memory)\n",
690 : gcov_info_filename(info));
691 : }
692 : }
693 0 : }
694 :
695 : /*
696 : * Disassociate a profiling data set from a node. Needs to be called with
697 : * node_lock held.
698 : */
699 0 : static void remove_info(struct gcov_node *node, struct gcov_info *info)
700 : {
701 0 : int i;
702 :
703 0 : i = get_info_index(node, info);
704 0 : if (i < 0) {
705 0 : pr_warn("could not remove '%s' (not found)\n",
706 : gcov_info_filename(info));
707 0 : return;
708 : }
709 0 : if (gcov_persist)
710 0 : save_info(node, info);
711 : /* Shrink array. */
712 0 : node->loaded_info[i] = node->loaded_info[node->num_loaded - 1];
713 0 : node->num_loaded--;
714 0 : if (node->num_loaded > 0)
715 : return;
716 : /* Last loaded data set was removed. */
717 0 : kfree(node->loaded_info);
718 0 : node->loaded_info = NULL;
719 0 : node->num_loaded = 0;
720 0 : if (!node->unloaded_info)
721 0 : remove_node(node);
722 : }
723 :
724 : /*
725 : * Callback to create/remove profiling files when code compiled with
726 : * -fprofile-arcs is loaded/unloaded.
727 : */
728 955 : void gcov_event(enum gcov_action action, struct gcov_info *info)
729 : {
730 955 : struct gcov_node *node;
731 :
732 955 : mutex_lock(&node_lock);
733 955 : node = get_node_by_name(gcov_info_filename(info));
734 955 : switch (action) {
735 955 : case GCOV_ADD:
736 955 : if (node)
737 0 : add_info(node, info);
738 : else
739 955 : add_node(info);
740 : break;
741 0 : case GCOV_REMOVE:
742 0 : if (node)
743 0 : remove_info(node, info);
744 : else {
745 0 : pr_warn("could not remove '%s' (not found)\n",
746 : gcov_info_filename(info));
747 : }
748 : break;
749 : }
750 955 : mutex_unlock(&node_lock);
751 955 : }
752 :
753 : /* Create debugfs entries. */
754 1 : static __init int gcov_fs_init(void)
755 : {
756 1 : init_node(&root_node, NULL, NULL, NULL);
757 : /*
758 : * /sys/kernel/debug/gcov will be parent for the reset control file
759 : * and all profiling files.
760 : */
761 1 : root_node.dentry = debugfs_create_dir("gcov", NULL);
762 : /*
763 : * Create reset file which resets all profiling counts when written
764 : * to.
765 : */
766 1 : debugfs_create_file("reset", 0600, root_node.dentry, NULL,
767 : &gcov_reset_fops);
768 : /* Replay previous events to get our fs hierarchy up-to-date. */
769 1 : gcov_enable_events();
770 1 : return 0;
771 : }
772 : device_initcall(gcov_fs_init);
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