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 <linux/mm.h> |
30 | #include "gcov.h" |
31 | |
32 | /** |
33 | * struct gcov_node - represents a debugfs entry |
34 | * @list: list head for child node list |
35 | * @children: child nodes |
36 | * @all: list head for list of all nodes |
37 | * @parent: parent node |
38 | * @loaded_info: array of pointers to profiling data sets for loaded object |
39 | * files. |
40 | * @num_loaded: number of profiling data sets for loaded object files. |
41 | * @unloaded_info: accumulated copy of profiling data sets for unloaded |
42 | * object files. Used only when gcov_persist=1. |
43 | * @dentry: main debugfs entry, either a directory or data file |
44 | * @links: associated symbolic links |
45 | * @name: data file basename |
46 | * |
47 | * struct gcov_node represents an entity within the gcov/ subdirectory |
48 | * of debugfs. There are directory and data file nodes. The latter represent |
49 | * the actual synthesized data file plus any associated symbolic links which |
50 | * are needed by the gcov tool to work correctly. |
51 | */ |
52 | struct gcov_node { |
53 | struct list_head list; |
54 | struct list_head children; |
55 | struct list_head all; |
56 | struct gcov_node *parent; |
57 | struct gcov_info **loaded_info; |
58 | struct gcov_info *unloaded_info; |
59 | struct dentry *dentry; |
60 | struct dentry **links; |
61 | int num_loaded; |
62 | char name[]; |
63 | }; |
64 | |
65 | static const char objtree[] = OBJTREE; |
66 | static const char srctree[] = SRCTREE; |
67 | static struct gcov_node root_node; |
68 | static LIST_HEAD(all_head); |
69 | static DEFINE_MUTEX(node_lock); |
70 | |
71 | /* If non-zero, keep copies of profiling data for unloaded modules. */ |
72 | static int gcov_persist = 1; |
73 | |
74 | static int __init gcov_persist_setup(char *str) |
75 | { |
76 | unsigned long val; |
77 | |
78 | if (kstrtoul(s: str, base: 0, res: &val)) { |
79 | pr_warn("invalid gcov_persist parameter '%s'\n" , str); |
80 | return 0; |
81 | } |
82 | gcov_persist = val; |
83 | pr_info("setting gcov_persist to %d\n" , gcov_persist); |
84 | |
85 | return 1; |
86 | } |
87 | __setup("gcov_persist=" , gcov_persist_setup); |
88 | |
89 | #define ITER_STRIDE PAGE_SIZE |
90 | |
91 | /** |
92 | * struct gcov_iterator - specifies current file position in logical records |
93 | * @info: associated profiling data |
94 | * @buffer: buffer containing file data |
95 | * @size: size of buffer |
96 | * @pos: current position in file |
97 | */ |
98 | struct gcov_iterator { |
99 | struct gcov_info *info; |
100 | size_t size; |
101 | loff_t pos; |
102 | char buffer[] __counted_by(size); |
103 | }; |
104 | |
105 | /** |
106 | * gcov_iter_new - allocate and initialize profiling data iterator |
107 | * @info: profiling data set to be iterated |
108 | * |
109 | * Return file iterator on success, %NULL otherwise. |
110 | */ |
111 | static struct gcov_iterator *gcov_iter_new(struct gcov_info *info) |
112 | { |
113 | struct gcov_iterator *iter; |
114 | size_t size; |
115 | |
116 | /* Dry-run to get the actual buffer size. */ |
117 | size = convert_to_gcda(NULL, info); |
118 | |
119 | iter = kvmalloc(struct_size(iter, buffer, size), GFP_KERNEL); |
120 | if (!iter) |
121 | return NULL; |
122 | |
123 | iter->info = info; |
124 | iter->size = size; |
125 | convert_to_gcda(buffer: iter->buffer, info); |
126 | |
127 | return iter; |
128 | } |
129 | |
130 | |
131 | /** |
132 | * gcov_iter_free - free iterator data |
133 | * @iter: file iterator |
134 | */ |
135 | static void gcov_iter_free(struct gcov_iterator *iter) |
136 | { |
137 | kvfree(addr: iter); |
138 | } |
139 | |
140 | /** |
141 | * gcov_iter_get_info - return profiling data set for given file iterator |
142 | * @iter: file iterator |
143 | */ |
144 | static struct gcov_info *gcov_iter_get_info(struct gcov_iterator *iter) |
145 | { |
146 | return iter->info; |
147 | } |
148 | |
149 | /** |
150 | * gcov_iter_start - reset file iterator to starting position |
151 | * @iter: file iterator |
152 | */ |
153 | static void gcov_iter_start(struct gcov_iterator *iter) |
154 | { |
155 | iter->pos = 0; |
156 | } |
157 | |
158 | /** |
159 | * gcov_iter_next - advance file iterator to next logical record |
160 | * @iter: file iterator |
161 | * |
162 | * Return zero if new position is valid, non-zero if iterator has reached end. |
163 | */ |
164 | static int gcov_iter_next(struct gcov_iterator *iter) |
165 | { |
166 | if (iter->pos < iter->size) |
167 | iter->pos += ITER_STRIDE; |
168 | |
169 | if (iter->pos >= iter->size) |
170 | return -EINVAL; |
171 | |
172 | return 0; |
173 | } |
174 | |
175 | /** |
176 | * gcov_iter_write - write data for current pos to seq_file |
177 | * @iter: file iterator |
178 | * @seq: seq_file handle |
179 | * |
180 | * Return zero on success, non-zero otherwise. |
181 | */ |
182 | static int gcov_iter_write(struct gcov_iterator *iter, struct seq_file *seq) |
183 | { |
184 | size_t len; |
185 | |
186 | if (iter->pos >= iter->size) |
187 | return -EINVAL; |
188 | |
189 | len = ITER_STRIDE; |
190 | if (iter->pos + len > iter->size) |
191 | len = iter->size - iter->pos; |
192 | |
193 | seq_write(seq, data: iter->buffer + iter->pos, len); |
194 | |
195 | return 0; |
196 | } |
197 | |
198 | /* |
199 | * seq_file.start() implementation for gcov data files. Note that the |
200 | * gcov_iterator interface is designed to be more restrictive than seq_file |
201 | * (no start from arbitrary position, etc.), to simplify the iterator |
202 | * implementation. |
203 | */ |
204 | static void *gcov_seq_start(struct seq_file *seq, loff_t *pos) |
205 | { |
206 | loff_t i; |
207 | |
208 | gcov_iter_start(iter: seq->private); |
209 | for (i = 0; i < *pos; i++) { |
210 | if (gcov_iter_next(iter: seq->private)) |
211 | return NULL; |
212 | } |
213 | return seq->private; |
214 | } |
215 | |
216 | /* seq_file.next() implementation for gcov data files. */ |
217 | static void *gcov_seq_next(struct seq_file *seq, void *data, loff_t *pos) |
218 | { |
219 | struct gcov_iterator *iter = data; |
220 | |
221 | (*pos)++; |
222 | if (gcov_iter_next(iter)) |
223 | return NULL; |
224 | |
225 | return iter; |
226 | } |
227 | |
228 | /* seq_file.show() implementation for gcov data files. */ |
229 | static int gcov_seq_show(struct seq_file *seq, void *data) |
230 | { |
231 | struct gcov_iterator *iter = data; |
232 | |
233 | if (gcov_iter_write(iter, seq)) |
234 | return -EINVAL; |
235 | return 0; |
236 | } |
237 | |
238 | static void gcov_seq_stop(struct seq_file *seq, void *data) |
239 | { |
240 | /* Unused. */ |
241 | } |
242 | |
243 | static const struct seq_operations gcov_seq_ops = { |
244 | .start = gcov_seq_start, |
245 | .next = gcov_seq_next, |
246 | .show = gcov_seq_show, |
247 | .stop = gcov_seq_stop, |
248 | }; |
249 | |
250 | /* |
251 | * Return a profiling data set associated with the given node. This is |
252 | * either a data set for a loaded object file or a data set copy in case |
253 | * all associated object files have been unloaded. |
254 | */ |
255 | static struct gcov_info *get_node_info(struct gcov_node *node) |
256 | { |
257 | if (node->num_loaded > 0) |
258 | return node->loaded_info[0]; |
259 | |
260 | return node->unloaded_info; |
261 | } |
262 | |
263 | /* |
264 | * Return a newly allocated profiling data set which contains the sum of |
265 | * all profiling data associated with the given node. |
266 | */ |
267 | static struct gcov_info *get_accumulated_info(struct gcov_node *node) |
268 | { |
269 | struct gcov_info *info; |
270 | int i = 0; |
271 | |
272 | if (node->unloaded_info) |
273 | info = gcov_info_dup(info: node->unloaded_info); |
274 | else |
275 | info = gcov_info_dup(info: node->loaded_info[i++]); |
276 | if (!info) |
277 | return NULL; |
278 | for (; i < node->num_loaded; i++) |
279 | gcov_info_add(dest: info, source: node->loaded_info[i]); |
280 | |
281 | return info; |
282 | } |
283 | |
284 | /* |
285 | * open() implementation for gcov data files. Create a copy of the profiling |
286 | * data set and initialize the iterator and seq_file interface. |
287 | */ |
288 | static int gcov_seq_open(struct inode *inode, struct file *file) |
289 | { |
290 | struct gcov_node *node = inode->i_private; |
291 | struct gcov_iterator *iter; |
292 | struct seq_file *seq; |
293 | struct gcov_info *info; |
294 | int rc = -ENOMEM; |
295 | |
296 | mutex_lock(&node_lock); |
297 | /* |
298 | * Read from a profiling data copy to minimize reference tracking |
299 | * complexity and concurrent access and to keep accumulating multiple |
300 | * profiling data sets associated with one node simple. |
301 | */ |
302 | info = get_accumulated_info(node); |
303 | if (!info) |
304 | goto out_unlock; |
305 | iter = gcov_iter_new(info); |
306 | if (!iter) |
307 | goto err_free_info; |
308 | rc = seq_open(file, &gcov_seq_ops); |
309 | if (rc) |
310 | goto err_free_iter_info; |
311 | seq = file->private_data; |
312 | seq->private = iter; |
313 | out_unlock: |
314 | mutex_unlock(lock: &node_lock); |
315 | return rc; |
316 | |
317 | err_free_iter_info: |
318 | gcov_iter_free(iter); |
319 | err_free_info: |
320 | gcov_info_free(info); |
321 | goto out_unlock; |
322 | } |
323 | |
324 | /* |
325 | * release() implementation for gcov data files. Release resources allocated |
326 | * by open(). |
327 | */ |
328 | static int gcov_seq_release(struct inode *inode, struct file *file) |
329 | { |
330 | struct gcov_iterator *iter; |
331 | struct gcov_info *info; |
332 | struct seq_file *seq; |
333 | |
334 | seq = file->private_data; |
335 | iter = seq->private; |
336 | info = gcov_iter_get_info(iter); |
337 | gcov_iter_free(iter); |
338 | gcov_info_free(info); |
339 | seq_release(inode, file); |
340 | |
341 | return 0; |
342 | } |
343 | |
344 | /* |
345 | * Find a node by the associated data file name. Needs to be called with |
346 | * node_lock held. |
347 | */ |
348 | static struct gcov_node *get_node_by_name(const char *name) |
349 | { |
350 | struct gcov_node *node; |
351 | struct gcov_info *info; |
352 | |
353 | list_for_each_entry(node, &all_head, all) { |
354 | info = get_node_info(node); |
355 | if (info && (strcmp(gcov_info_filename(info), name) == 0)) |
356 | return node; |
357 | } |
358 | |
359 | return NULL; |
360 | } |
361 | |
362 | /* |
363 | * Reset all profiling data associated with the specified node. |
364 | */ |
365 | static void reset_node(struct gcov_node *node) |
366 | { |
367 | int i; |
368 | |
369 | if (node->unloaded_info) |
370 | gcov_info_reset(info: node->unloaded_info); |
371 | for (i = 0; i < node->num_loaded; i++) |
372 | gcov_info_reset(info: node->loaded_info[i]); |
373 | } |
374 | |
375 | static void remove_node(struct gcov_node *node); |
376 | |
377 | /* |
378 | * write() implementation for gcov data files. Reset profiling data for the |
379 | * corresponding file. If all associated object files have been unloaded, |
380 | * remove the debug fs node as well. |
381 | */ |
382 | static ssize_t gcov_seq_write(struct file *file, const char __user *addr, |
383 | size_t len, loff_t *pos) |
384 | { |
385 | struct seq_file *seq; |
386 | struct gcov_info *info; |
387 | struct gcov_node *node; |
388 | |
389 | seq = file->private_data; |
390 | info = gcov_iter_get_info(iter: seq->private); |
391 | mutex_lock(&node_lock); |
392 | node = get_node_by_name(name: gcov_info_filename(info)); |
393 | if (node) { |
394 | /* Reset counts or remove node for unloaded modules. */ |
395 | if (node->num_loaded == 0) |
396 | remove_node(node); |
397 | else |
398 | reset_node(node); |
399 | } |
400 | /* Reset counts for open file. */ |
401 | gcov_info_reset(info); |
402 | mutex_unlock(lock: &node_lock); |
403 | |
404 | return len; |
405 | } |
406 | |
407 | /* |
408 | * Given a string <path> representing a file path of format: |
409 | * path/to/file.gcda |
410 | * construct and return a new string: |
411 | * <dir/>path/to/file.<ext> |
412 | */ |
413 | static char *link_target(const char *dir, const char *path, const char *ext) |
414 | { |
415 | char *target; |
416 | char *old_ext; |
417 | char *copy; |
418 | |
419 | copy = kstrdup(s: path, GFP_KERNEL); |
420 | if (!copy) |
421 | return NULL; |
422 | old_ext = strrchr(copy, '.'); |
423 | if (old_ext) |
424 | *old_ext = '\0'; |
425 | if (dir) |
426 | target = kasprintf(GFP_KERNEL, fmt: "%s/%s.%s" , dir, copy, ext); |
427 | else |
428 | target = kasprintf(GFP_KERNEL, fmt: "%s.%s" , copy, ext); |
429 | kfree(objp: copy); |
430 | |
431 | return target; |
432 | } |
433 | |
434 | /* |
435 | * Construct a string representing the symbolic link target for the given |
436 | * gcov data file name and link type. Depending on the link type and the |
437 | * location of the data file, the link target can either point to a |
438 | * subdirectory of srctree, objtree or in an external location. |
439 | */ |
440 | static char *get_link_target(const char *filename, const struct gcov_link *ext) |
441 | { |
442 | const char *rel; |
443 | char *result; |
444 | |
445 | if (strncmp(filename, objtree, strlen(objtree)) == 0) { |
446 | rel = filename + strlen(objtree) + 1; |
447 | if (ext->dir == SRC_TREE) |
448 | result = link_target(dir: srctree, path: rel, ext: ext->ext); |
449 | else |
450 | result = link_target(dir: objtree, path: rel, ext: ext->ext); |
451 | } else { |
452 | /* External compilation. */ |
453 | result = link_target(NULL, path: filename, ext: ext->ext); |
454 | } |
455 | |
456 | return result; |
457 | } |
458 | |
459 | #define SKEW_PREFIX ".tmp_" |
460 | |
461 | /* |
462 | * For a filename .tmp_filename.ext return filename.ext. Needed to compensate |
463 | * for filename skewing caused by the mod-versioning mechanism. |
464 | */ |
465 | static const char *deskew(const char *basename) |
466 | { |
467 | if (strncmp(basename, SKEW_PREFIX, sizeof(SKEW_PREFIX) - 1) == 0) |
468 | return basename + sizeof(SKEW_PREFIX) - 1; |
469 | return basename; |
470 | } |
471 | |
472 | /* |
473 | * Create links to additional files (usually .c and .gcno files) which the |
474 | * gcov tool expects to find in the same directory as the gcov data file. |
475 | */ |
476 | static void add_links(struct gcov_node *node, struct dentry *parent) |
477 | { |
478 | const char *basename; |
479 | char *target; |
480 | int num; |
481 | int i; |
482 | |
483 | for (num = 0; gcov_link[num].ext; num++) |
484 | /* Nothing. */; |
485 | node->links = kcalloc(n: num, size: sizeof(struct dentry *), GFP_KERNEL); |
486 | if (!node->links) |
487 | return; |
488 | for (i = 0; i < num; i++) { |
489 | target = get_link_target( |
490 | filename: gcov_info_filename(info: get_node_info(node)), |
491 | ext: &gcov_link[i]); |
492 | if (!target) |
493 | goto out_err; |
494 | basename = kbasename(path: target); |
495 | if (basename == target) |
496 | goto out_err; |
497 | node->links[i] = debugfs_create_symlink(name: deskew(basename), |
498 | parent, dest: target); |
499 | kfree(objp: target); |
500 | } |
501 | |
502 | return; |
503 | out_err: |
504 | kfree(objp: target); |
505 | while (i-- > 0) |
506 | debugfs_remove(dentry: node->links[i]); |
507 | kfree(objp: node->links); |
508 | node->links = NULL; |
509 | } |
510 | |
511 | static const struct file_operations gcov_data_fops = { |
512 | .open = gcov_seq_open, |
513 | .release = gcov_seq_release, |
514 | .read = seq_read, |
515 | .llseek = seq_lseek, |
516 | .write = gcov_seq_write, |
517 | }; |
518 | |
519 | /* Basic initialization of a new node. */ |
520 | static void init_node(struct gcov_node *node, struct gcov_info *info, |
521 | const char *name, struct gcov_node *parent) |
522 | { |
523 | INIT_LIST_HEAD(list: &node->list); |
524 | INIT_LIST_HEAD(list: &node->children); |
525 | INIT_LIST_HEAD(list: &node->all); |
526 | if (node->loaded_info) { |
527 | node->loaded_info[0] = info; |
528 | node->num_loaded = 1; |
529 | } |
530 | node->parent = parent; |
531 | if (name) |
532 | strcpy(p: node->name, q: name); |
533 | } |
534 | |
535 | /* |
536 | * Create a new node and associated debugfs entry. Needs to be called with |
537 | * node_lock held. |
538 | */ |
539 | static struct gcov_node *new_node(struct gcov_node *parent, |
540 | struct gcov_info *info, const char *name) |
541 | { |
542 | struct gcov_node *node; |
543 | |
544 | node = kzalloc(size: sizeof(struct gcov_node) + strlen(name) + 1, GFP_KERNEL); |
545 | if (!node) |
546 | goto err_nomem; |
547 | if (info) { |
548 | node->loaded_info = kcalloc(n: 1, size: sizeof(struct gcov_info *), |
549 | GFP_KERNEL); |
550 | if (!node->loaded_info) |
551 | goto err_nomem; |
552 | } |
553 | init_node(node, info, name, parent); |
554 | /* Differentiate between gcov data file nodes and directory nodes. */ |
555 | if (info) { |
556 | node->dentry = debugfs_create_file(name: deskew(basename: node->name), mode: 0600, |
557 | parent: parent->dentry, data: node, fops: &gcov_data_fops); |
558 | } else |
559 | node->dentry = debugfs_create_dir(name: node->name, parent: parent->dentry); |
560 | if (info) |
561 | add_links(node, parent: parent->dentry); |
562 | list_add(new: &node->list, head: &parent->children); |
563 | list_add(new: &node->all, head: &all_head); |
564 | |
565 | return node; |
566 | |
567 | err_nomem: |
568 | kfree(objp: node); |
569 | pr_warn("out of memory\n" ); |
570 | return NULL; |
571 | } |
572 | |
573 | /* Remove symbolic links associated with node. */ |
574 | static void remove_links(struct gcov_node *node) |
575 | { |
576 | int i; |
577 | |
578 | if (!node->links) |
579 | return; |
580 | for (i = 0; gcov_link[i].ext; i++) |
581 | debugfs_remove(dentry: node->links[i]); |
582 | kfree(objp: node->links); |
583 | node->links = NULL; |
584 | } |
585 | |
586 | /* |
587 | * Remove node from all lists and debugfs and release associated resources. |
588 | * Needs to be called with node_lock held. |
589 | */ |
590 | static void release_node(struct gcov_node *node) |
591 | { |
592 | list_del(entry: &node->list); |
593 | list_del(entry: &node->all); |
594 | debugfs_remove(dentry: node->dentry); |
595 | remove_links(node); |
596 | kfree(objp: node->loaded_info); |
597 | if (node->unloaded_info) |
598 | gcov_info_free(info: node->unloaded_info); |
599 | kfree(objp: node); |
600 | } |
601 | |
602 | /* Release node and empty parents. Needs to be called with node_lock held. */ |
603 | static void remove_node(struct gcov_node *node) |
604 | { |
605 | struct gcov_node *parent; |
606 | |
607 | while ((node != &root_node) && list_empty(head: &node->children)) { |
608 | parent = node->parent; |
609 | release_node(node); |
610 | node = parent; |
611 | } |
612 | } |
613 | |
614 | /* |
615 | * Find child node with given basename. Needs to be called with node_lock |
616 | * held. |
617 | */ |
618 | static struct gcov_node *get_child_by_name(struct gcov_node *parent, |
619 | const char *name) |
620 | { |
621 | struct gcov_node *node; |
622 | |
623 | list_for_each_entry(node, &parent->children, list) { |
624 | if (strcmp(node->name, name) == 0) |
625 | return node; |
626 | } |
627 | |
628 | return NULL; |
629 | } |
630 | |
631 | /* |
632 | * write() implementation for reset file. Reset all profiling data to zero |
633 | * and remove nodes for which all associated object files are unloaded. |
634 | */ |
635 | static ssize_t reset_write(struct file *file, const char __user *addr, |
636 | size_t len, loff_t *pos) |
637 | { |
638 | struct gcov_node *node; |
639 | |
640 | mutex_lock(&node_lock); |
641 | restart: |
642 | list_for_each_entry(node, &all_head, all) { |
643 | if (node->num_loaded > 0) |
644 | reset_node(node); |
645 | else if (list_empty(head: &node->children)) { |
646 | remove_node(node); |
647 | /* Several nodes may have gone - restart loop. */ |
648 | goto restart; |
649 | } |
650 | } |
651 | mutex_unlock(lock: &node_lock); |
652 | |
653 | return len; |
654 | } |
655 | |
656 | /* read() implementation for reset file. Unused. */ |
657 | static ssize_t reset_read(struct file *file, char __user *addr, size_t len, |
658 | loff_t *pos) |
659 | { |
660 | /* Allow read operation so that a recursive copy won't fail. */ |
661 | return 0; |
662 | } |
663 | |
664 | static const struct file_operations gcov_reset_fops = { |
665 | .write = reset_write, |
666 | .read = reset_read, |
667 | .llseek = noop_llseek, |
668 | }; |
669 | |
670 | /* |
671 | * Create a node for a given profiling data set and add it to all lists and |
672 | * debugfs. Needs to be called with node_lock held. |
673 | */ |
674 | static void add_node(struct gcov_info *info) |
675 | { |
676 | char *filename; |
677 | char *curr; |
678 | char *next; |
679 | struct gcov_node *parent; |
680 | struct gcov_node *node; |
681 | |
682 | filename = kstrdup(s: gcov_info_filename(info), GFP_KERNEL); |
683 | if (!filename) |
684 | return; |
685 | parent = &root_node; |
686 | /* Create directory nodes along the path. */ |
687 | for (curr = filename; (next = strchr(curr, '/')); curr = next + 1) { |
688 | if (curr == next) |
689 | continue; |
690 | *next = 0; |
691 | if (strcmp(curr, "." ) == 0) |
692 | continue; |
693 | if (strcmp(curr, ".." ) == 0) { |
694 | if (!parent->parent) |
695 | goto err_remove; |
696 | parent = parent->parent; |
697 | continue; |
698 | } |
699 | node = get_child_by_name(parent, name: curr); |
700 | if (!node) { |
701 | node = new_node(parent, NULL, name: curr); |
702 | if (!node) |
703 | goto err_remove; |
704 | } |
705 | parent = node; |
706 | } |
707 | /* Create file node. */ |
708 | node = new_node(parent, info, name: curr); |
709 | if (!node) |
710 | goto err_remove; |
711 | out: |
712 | kfree(objp: filename); |
713 | return; |
714 | |
715 | err_remove: |
716 | remove_node(node: parent); |
717 | goto out; |
718 | } |
719 | |
720 | /* |
721 | * Associate a profiling data set with an existing node. Needs to be called |
722 | * with node_lock held. |
723 | */ |
724 | static void add_info(struct gcov_node *node, struct gcov_info *info) |
725 | { |
726 | struct gcov_info **loaded_info; |
727 | int num = node->num_loaded; |
728 | |
729 | /* |
730 | * Prepare new array. This is done first to simplify cleanup in |
731 | * case the new data set is incompatible, the node only contains |
732 | * unloaded data sets and there's not enough memory for the array. |
733 | */ |
734 | loaded_info = kcalloc(n: num + 1, size: sizeof(struct gcov_info *), GFP_KERNEL); |
735 | if (!loaded_info) { |
736 | pr_warn("could not add '%s' (out of memory)\n" , |
737 | gcov_info_filename(info)); |
738 | return; |
739 | } |
740 | memcpy(loaded_info, node->loaded_info, |
741 | num * sizeof(struct gcov_info *)); |
742 | loaded_info[num] = info; |
743 | /* Check if the new data set is compatible. */ |
744 | if (num == 0) { |
745 | /* |
746 | * A module was unloaded, modified and reloaded. The new |
747 | * data set replaces the copy of the last one. |
748 | */ |
749 | if (!gcov_info_is_compatible(info1: node->unloaded_info, info2: info)) { |
750 | pr_warn("discarding saved data for %s " |
751 | "(incompatible version)\n" , |
752 | gcov_info_filename(info)); |
753 | gcov_info_free(info: node->unloaded_info); |
754 | node->unloaded_info = NULL; |
755 | } |
756 | } else { |
757 | /* |
758 | * Two different versions of the same object file are loaded. |
759 | * The initial one takes precedence. |
760 | */ |
761 | if (!gcov_info_is_compatible(info1: node->loaded_info[0], info2: info)) { |
762 | pr_warn("could not add '%s' (incompatible " |
763 | "version)\n" , gcov_info_filename(info)); |
764 | kfree(objp: loaded_info); |
765 | return; |
766 | } |
767 | } |
768 | /* Overwrite previous array. */ |
769 | kfree(objp: node->loaded_info); |
770 | node->loaded_info = loaded_info; |
771 | node->num_loaded = num + 1; |
772 | } |
773 | |
774 | /* |
775 | * Return the index of a profiling data set associated with a node. |
776 | */ |
777 | static int get_info_index(struct gcov_node *node, struct gcov_info *info) |
778 | { |
779 | int i; |
780 | |
781 | for (i = 0; i < node->num_loaded; i++) { |
782 | if (node->loaded_info[i] == info) |
783 | return i; |
784 | } |
785 | return -ENOENT; |
786 | } |
787 | |
788 | /* |
789 | * Save the data of a profiling data set which is being unloaded. |
790 | */ |
791 | static void save_info(struct gcov_node *node, struct gcov_info *info) |
792 | { |
793 | if (node->unloaded_info) |
794 | gcov_info_add(dest: node->unloaded_info, source: info); |
795 | else { |
796 | node->unloaded_info = gcov_info_dup(info); |
797 | if (!node->unloaded_info) { |
798 | pr_warn("could not save data for '%s' " |
799 | "(out of memory)\n" , |
800 | gcov_info_filename(info)); |
801 | } |
802 | } |
803 | } |
804 | |
805 | /* |
806 | * Disassociate a profiling data set from a node. Needs to be called with |
807 | * node_lock held. |
808 | */ |
809 | static void remove_info(struct gcov_node *node, struct gcov_info *info) |
810 | { |
811 | int i; |
812 | |
813 | i = get_info_index(node, info); |
814 | if (i < 0) { |
815 | pr_warn("could not remove '%s' (not found)\n" , |
816 | gcov_info_filename(info)); |
817 | return; |
818 | } |
819 | if (gcov_persist) |
820 | save_info(node, info); |
821 | /* Shrink array. */ |
822 | node->loaded_info[i] = node->loaded_info[node->num_loaded - 1]; |
823 | node->num_loaded--; |
824 | if (node->num_loaded > 0) |
825 | return; |
826 | /* Last loaded data set was removed. */ |
827 | kfree(objp: node->loaded_info); |
828 | node->loaded_info = NULL; |
829 | node->num_loaded = 0; |
830 | if (!node->unloaded_info) |
831 | remove_node(node); |
832 | } |
833 | |
834 | /* |
835 | * Callback to create/remove profiling files when code compiled with |
836 | * -fprofile-arcs is loaded/unloaded. |
837 | */ |
838 | void gcov_event(enum gcov_action action, struct gcov_info *info) |
839 | { |
840 | struct gcov_node *node; |
841 | |
842 | mutex_lock(&node_lock); |
843 | node = get_node_by_name(name: gcov_info_filename(info)); |
844 | switch (action) { |
845 | case GCOV_ADD: |
846 | if (node) |
847 | add_info(node, info); |
848 | else |
849 | add_node(info); |
850 | break; |
851 | case GCOV_REMOVE: |
852 | if (node) |
853 | remove_info(node, info); |
854 | else { |
855 | pr_warn("could not remove '%s' (not found)\n" , |
856 | gcov_info_filename(info)); |
857 | } |
858 | break; |
859 | } |
860 | mutex_unlock(lock: &node_lock); |
861 | } |
862 | |
863 | /* Create debugfs entries. */ |
864 | static __init int gcov_fs_init(void) |
865 | { |
866 | init_node(node: &root_node, NULL, NULL, NULL); |
867 | /* |
868 | * /sys/kernel/debug/gcov will be parent for the reset control file |
869 | * and all profiling files. |
870 | */ |
871 | root_node.dentry = debugfs_create_dir(name: "gcov" , NULL); |
872 | /* |
873 | * Create reset file which resets all profiling counts when written |
874 | * to. |
875 | */ |
876 | debugfs_create_file(name: "reset" , mode: 0600, parent: root_node.dentry, NULL, |
877 | fops: &gcov_reset_fops); |
878 | /* Replay previous events to get our fs hierarchy up-to-date. */ |
879 | gcov_enable_events(); |
880 | return 0; |
881 | } |
882 | device_initcall(gcov_fs_init); |
883 | |