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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
2521f2c2 PO |
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 | |
85a0fdfd PO |
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. | |
2521f2c2 PO |
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; | |
85a0fdfd PO |
56 | struct gcov_info **loaded_info; |
57 | struct gcov_info *unloaded_info; | |
2521f2c2 PO |
58 | struct dentry *dentry; |
59 | struct dentry **links; | |
85a0fdfd | 60 | int num_loaded; |
2521f2c2 PO |
61 | char name[0]; |
62 | }; | |
63 | ||
64 | static const char objtree[] = OBJTREE; | |
65 | static const char srctree[] = SRCTREE; | |
66 | static struct gcov_node root_node; | |
67 | static struct dentry *reset_dentry; | |
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 | ||
6072ddc8 | 78 | if (kstrtoul(str, 0, &val)) { |
a5ebb875 | 79 | pr_warn("invalid gcov_persist parameter '%s'\n", str); |
2521f2c2 PO |
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 | /* | |
90 | * seq_file.start() implementation for gcov data files. Note that the | |
91 | * gcov_iterator interface is designed to be more restrictive than seq_file | |
92 | * (no start from arbitrary position, etc.), to simplify the iterator | |
93 | * implementation. | |
94 | */ | |
95 | static void *gcov_seq_start(struct seq_file *seq, loff_t *pos) | |
96 | { | |
97 | loff_t i; | |
98 | ||
99 | gcov_iter_start(seq->private); | |
100 | for (i = 0; i < *pos; i++) { | |
101 | if (gcov_iter_next(seq->private)) | |
102 | return NULL; | |
103 | } | |
104 | return seq->private; | |
105 | } | |
106 | ||
107 | /* seq_file.next() implementation for gcov data files. */ | |
108 | static void *gcov_seq_next(struct seq_file *seq, void *data, loff_t *pos) | |
109 | { | |
110 | struct gcov_iterator *iter = data; | |
111 | ||
112 | if (gcov_iter_next(iter)) | |
113 | return NULL; | |
114 | (*pos)++; | |
115 | ||
116 | return iter; | |
117 | } | |
118 | ||
119 | /* seq_file.show() implementation for gcov data files. */ | |
120 | static int gcov_seq_show(struct seq_file *seq, void *data) | |
121 | { | |
122 | struct gcov_iterator *iter = data; | |
123 | ||
124 | if (gcov_iter_write(iter, seq)) | |
125 | return -EINVAL; | |
126 | return 0; | |
127 | } | |
128 | ||
129 | static void gcov_seq_stop(struct seq_file *seq, void *data) | |
130 | { | |
131 | /* Unused. */ | |
132 | } | |
133 | ||
134 | static const struct seq_operations gcov_seq_ops = { | |
135 | .start = gcov_seq_start, | |
136 | .next = gcov_seq_next, | |
137 | .show = gcov_seq_show, | |
138 | .stop = gcov_seq_stop, | |
139 | }; | |
140 | ||
141 | /* | |
85a0fdfd PO |
142 | * Return a profiling data set associated with the given node. This is |
143 | * either a data set for a loaded object file or a data set copy in case | |
144 | * all associated object files have been unloaded. | |
2521f2c2 PO |
145 | */ |
146 | static struct gcov_info *get_node_info(struct gcov_node *node) | |
147 | { | |
85a0fdfd PO |
148 | if (node->num_loaded > 0) |
149 | return node->loaded_info[0]; | |
2521f2c2 | 150 | |
85a0fdfd PO |
151 | return node->unloaded_info; |
152 | } | |
153 | ||
154 | /* | |
155 | * Return a newly allocated profiling data set which contains the sum of | |
156 | * all profiling data associated with the given node. | |
157 | */ | |
158 | static struct gcov_info *get_accumulated_info(struct gcov_node *node) | |
159 | { | |
160 | struct gcov_info *info; | |
161 | int i = 0; | |
162 | ||
163 | if (node->unloaded_info) | |
164 | info = gcov_info_dup(node->unloaded_info); | |
165 | else | |
166 | info = gcov_info_dup(node->loaded_info[i++]); | |
167 | if (!info) | |
168 | return NULL; | |
169 | for (; i < node->num_loaded; i++) | |
170 | gcov_info_add(info, node->loaded_info[i]); | |
171 | ||
172 | return info; | |
2521f2c2 PO |
173 | } |
174 | ||
175 | /* | |
176 | * open() implementation for gcov data files. Create a copy of the profiling | |
177 | * data set and initialize the iterator and seq_file interface. | |
178 | */ | |
179 | static int gcov_seq_open(struct inode *inode, struct file *file) | |
180 | { | |
181 | struct gcov_node *node = inode->i_private; | |
182 | struct gcov_iterator *iter; | |
183 | struct seq_file *seq; | |
184 | struct gcov_info *info; | |
185 | int rc = -ENOMEM; | |
186 | ||
187 | mutex_lock(&node_lock); | |
188 | /* | |
189 | * Read from a profiling data copy to minimize reference tracking | |
85a0fdfd PO |
190 | * complexity and concurrent access and to keep accumulating multiple |
191 | * profiling data sets associated with one node simple. | |
2521f2c2 | 192 | */ |
85a0fdfd | 193 | info = get_accumulated_info(node); |
2521f2c2 PO |
194 | if (!info) |
195 | goto out_unlock; | |
196 | iter = gcov_iter_new(info); | |
197 | if (!iter) | |
198 | goto err_free_info; | |
199 | rc = seq_open(file, &gcov_seq_ops); | |
200 | if (rc) | |
201 | goto err_free_iter_info; | |
202 | seq = file->private_data; | |
203 | seq->private = iter; | |
204 | out_unlock: | |
205 | mutex_unlock(&node_lock); | |
206 | return rc; | |
207 | ||
208 | err_free_iter_info: | |
209 | gcov_iter_free(iter); | |
210 | err_free_info: | |
211 | gcov_info_free(info); | |
212 | goto out_unlock; | |
213 | } | |
214 | ||
215 | /* | |
216 | * release() implementation for gcov data files. Release resources allocated | |
217 | * by open(). | |
218 | */ | |
219 | static int gcov_seq_release(struct inode *inode, struct file *file) | |
220 | { | |
221 | struct gcov_iterator *iter; | |
222 | struct gcov_info *info; | |
223 | struct seq_file *seq; | |
224 | ||
225 | seq = file->private_data; | |
226 | iter = seq->private; | |
227 | info = gcov_iter_get_info(iter); | |
228 | gcov_iter_free(iter); | |
229 | gcov_info_free(info); | |
230 | seq_release(inode, file); | |
231 | ||
232 | return 0; | |
233 | } | |
234 | ||
235 | /* | |
236 | * Find a node by the associated data file name. Needs to be called with | |
237 | * node_lock held. | |
238 | */ | |
239 | static struct gcov_node *get_node_by_name(const char *name) | |
240 | { | |
241 | struct gcov_node *node; | |
242 | struct gcov_info *info; | |
243 | ||
244 | list_for_each_entry(node, &all_head, all) { | |
245 | info = get_node_info(node); | |
8cbce376 | 246 | if (info && (strcmp(gcov_info_filename(info), name) == 0)) |
2521f2c2 PO |
247 | return node; |
248 | } | |
249 | ||
250 | return NULL; | |
251 | } | |
252 | ||
85a0fdfd PO |
253 | /* |
254 | * Reset all profiling data associated with the specified node. | |
255 | */ | |
256 | static void reset_node(struct gcov_node *node) | |
257 | { | |
258 | int i; | |
259 | ||
260 | if (node->unloaded_info) | |
261 | gcov_info_reset(node->unloaded_info); | |
262 | for (i = 0; i < node->num_loaded; i++) | |
263 | gcov_info_reset(node->loaded_info[i]); | |
264 | } | |
265 | ||
2521f2c2 PO |
266 | static void remove_node(struct gcov_node *node); |
267 | ||
268 | /* | |
269 | * write() implementation for gcov data files. Reset profiling data for the | |
85a0fdfd PO |
270 | * corresponding file. If all associated object files have been unloaded, |
271 | * remove the debug fs node as well. | |
2521f2c2 PO |
272 | */ |
273 | static ssize_t gcov_seq_write(struct file *file, const char __user *addr, | |
274 | size_t len, loff_t *pos) | |
275 | { | |
276 | struct seq_file *seq; | |
277 | struct gcov_info *info; | |
278 | struct gcov_node *node; | |
279 | ||
280 | seq = file->private_data; | |
281 | info = gcov_iter_get_info(seq->private); | |
282 | mutex_lock(&node_lock); | |
8cbce376 | 283 | node = get_node_by_name(gcov_info_filename(info)); |
2521f2c2 PO |
284 | if (node) { |
285 | /* Reset counts or remove node for unloaded modules. */ | |
85a0fdfd | 286 | if (node->num_loaded == 0) |
2521f2c2 PO |
287 | remove_node(node); |
288 | else | |
85a0fdfd | 289 | reset_node(node); |
2521f2c2 PO |
290 | } |
291 | /* Reset counts for open file. */ | |
292 | gcov_info_reset(info); | |
293 | mutex_unlock(&node_lock); | |
294 | ||
295 | return len; | |
296 | } | |
297 | ||
298 | /* | |
299 | * Given a string <path> representing a file path of format: | |
300 | * path/to/file.gcda | |
301 | * construct and return a new string: | |
302 | * <dir/>path/to/file.<ext> | |
303 | */ | |
304 | static char *link_target(const char *dir, const char *path, const char *ext) | |
305 | { | |
306 | char *target; | |
307 | char *old_ext; | |
308 | char *copy; | |
309 | ||
310 | copy = kstrdup(path, GFP_KERNEL); | |
311 | if (!copy) | |
312 | return NULL; | |
313 | old_ext = strrchr(copy, '.'); | |
314 | if (old_ext) | |
315 | *old_ext = '\0'; | |
316 | if (dir) | |
317 | target = kasprintf(GFP_KERNEL, "%s/%s.%s", dir, copy, ext); | |
318 | else | |
319 | target = kasprintf(GFP_KERNEL, "%s.%s", copy, ext); | |
320 | kfree(copy); | |
321 | ||
322 | return target; | |
323 | } | |
324 | ||
325 | /* | |
326 | * Construct a string representing the symbolic link target for the given | |
327 | * gcov data file name and link type. Depending on the link type and the | |
328 | * location of the data file, the link target can either point to a | |
329 | * subdirectory of srctree, objtree or in an external location. | |
330 | */ | |
331 | static char *get_link_target(const char *filename, const struct gcov_link *ext) | |
332 | { | |
333 | const char *rel; | |
334 | char *result; | |
335 | ||
336 | if (strncmp(filename, objtree, strlen(objtree)) == 0) { | |
337 | rel = filename + strlen(objtree) + 1; | |
338 | if (ext->dir == SRC_TREE) | |
339 | result = link_target(srctree, rel, ext->ext); | |
340 | else | |
341 | result = link_target(objtree, rel, ext->ext); | |
342 | } else { | |
343 | /* External compilation. */ | |
344 | result = link_target(NULL, filename, ext->ext); | |
345 | } | |
346 | ||
347 | return result; | |
348 | } | |
349 | ||
350 | #define SKEW_PREFIX ".tmp_" | |
351 | ||
352 | /* | |
353 | * For a filename .tmp_filename.ext return filename.ext. Needed to compensate | |
354 | * for filename skewing caused by the mod-versioning mechanism. | |
355 | */ | |
356 | static const char *deskew(const char *basename) | |
357 | { | |
358 | if (strncmp(basename, SKEW_PREFIX, sizeof(SKEW_PREFIX) - 1) == 0) | |
359 | return basename + sizeof(SKEW_PREFIX) - 1; | |
360 | return basename; | |
361 | } | |
362 | ||
363 | /* | |
364 | * Create links to additional files (usually .c and .gcno files) which the | |
365 | * gcov tool expects to find in the same directory as the gcov data file. | |
366 | */ | |
367 | static void add_links(struct gcov_node *node, struct dentry *parent) | |
368 | { | |
1931d433 | 369 | const char *basename; |
2521f2c2 PO |
370 | char *target; |
371 | int num; | |
372 | int i; | |
373 | ||
374 | for (num = 0; gcov_link[num].ext; num++) | |
375 | /* Nothing. */; | |
376 | node->links = kcalloc(num, sizeof(struct dentry *), GFP_KERNEL); | |
377 | if (!node->links) | |
378 | return; | |
379 | for (i = 0; i < num; i++) { | |
8cbce376 FH |
380 | target = get_link_target( |
381 | gcov_info_filename(get_node_info(node)), | |
382 | &gcov_link[i]); | |
2521f2c2 PO |
383 | if (!target) |
384 | goto out_err; | |
1931d433 AS |
385 | basename = kbasename(target); |
386 | if (basename == target) | |
2521f2c2 | 387 | goto out_err; |
2521f2c2 PO |
388 | node->links[i] = debugfs_create_symlink(deskew(basename), |
389 | parent, target); | |
390 | if (!node->links[i]) | |
391 | goto out_err; | |
392 | kfree(target); | |
393 | } | |
394 | ||
395 | return; | |
396 | out_err: | |
397 | kfree(target); | |
398 | while (i-- > 0) | |
399 | debugfs_remove(node->links[i]); | |
400 | kfree(node->links); | |
401 | node->links = NULL; | |
402 | } | |
403 | ||
404 | static const struct file_operations gcov_data_fops = { | |
405 | .open = gcov_seq_open, | |
406 | .release = gcov_seq_release, | |
407 | .read = seq_read, | |
408 | .llseek = seq_lseek, | |
409 | .write = gcov_seq_write, | |
410 | }; | |
411 | ||
412 | /* Basic initialization of a new node. */ | |
413 | static void init_node(struct gcov_node *node, struct gcov_info *info, | |
414 | const char *name, struct gcov_node *parent) | |
415 | { | |
416 | INIT_LIST_HEAD(&node->list); | |
417 | INIT_LIST_HEAD(&node->children); | |
418 | INIT_LIST_HEAD(&node->all); | |
85a0fdfd PO |
419 | if (node->loaded_info) { |
420 | node->loaded_info[0] = info; | |
421 | node->num_loaded = 1; | |
422 | } | |
2521f2c2 PO |
423 | node->parent = parent; |
424 | if (name) | |
425 | strcpy(node->name, name); | |
426 | } | |
427 | ||
428 | /* | |
429 | * Create a new node and associated debugfs entry. Needs to be called with | |
430 | * node_lock held. | |
431 | */ | |
432 | static struct gcov_node *new_node(struct gcov_node *parent, | |
433 | struct gcov_info *info, const char *name) | |
434 | { | |
435 | struct gcov_node *node; | |
436 | ||
437 | node = kzalloc(sizeof(struct gcov_node) + strlen(name) + 1, GFP_KERNEL); | |
85a0fdfd PO |
438 | if (!node) |
439 | goto err_nomem; | |
440 | if (info) { | |
441 | node->loaded_info = kcalloc(1, sizeof(struct gcov_info *), | |
442 | GFP_KERNEL); | |
443 | if (!node->loaded_info) | |
444 | goto err_nomem; | |
2521f2c2 PO |
445 | } |
446 | init_node(node, info, name, parent); | |
447 | /* Differentiate between gcov data file nodes and directory nodes. */ | |
448 | if (info) { | |
449 | node->dentry = debugfs_create_file(deskew(node->name), 0600, | |
450 | parent->dentry, node, &gcov_data_fops); | |
451 | } else | |
452 | node->dentry = debugfs_create_dir(node->name, parent->dentry); | |
453 | if (!node->dentry) { | |
a5ebb875 | 454 | pr_warn("could not create file\n"); |
2521f2c2 PO |
455 | kfree(node); |
456 | return NULL; | |
457 | } | |
458 | if (info) | |
459 | add_links(node, parent->dentry); | |
460 | list_add(&node->list, &parent->children); | |
461 | list_add(&node->all, &all_head); | |
462 | ||
463 | return node; | |
85a0fdfd PO |
464 | |
465 | err_nomem: | |
466 | kfree(node); | |
a5ebb875 | 467 | pr_warn("out of memory\n"); |
85a0fdfd | 468 | return NULL; |
2521f2c2 PO |
469 | } |
470 | ||
471 | /* Remove symbolic links associated with node. */ | |
472 | static void remove_links(struct gcov_node *node) | |
473 | { | |
474 | int i; | |
475 | ||
476 | if (!node->links) | |
477 | return; | |
478 | for (i = 0; gcov_link[i].ext; i++) | |
479 | debugfs_remove(node->links[i]); | |
480 | kfree(node->links); | |
481 | node->links = NULL; | |
482 | } | |
483 | ||
484 | /* | |
485 | * Remove node from all lists and debugfs and release associated resources. | |
486 | * Needs to be called with node_lock held. | |
487 | */ | |
488 | static void release_node(struct gcov_node *node) | |
489 | { | |
490 | list_del(&node->list); | |
491 | list_del(&node->all); | |
492 | debugfs_remove(node->dentry); | |
493 | remove_links(node); | |
85a0fdfd PO |
494 | kfree(node->loaded_info); |
495 | if (node->unloaded_info) | |
496 | gcov_info_free(node->unloaded_info); | |
2521f2c2 PO |
497 | kfree(node); |
498 | } | |
499 | ||
500 | /* Release node and empty parents. Needs to be called with node_lock held. */ | |
501 | static void remove_node(struct gcov_node *node) | |
502 | { | |
503 | struct gcov_node *parent; | |
504 | ||
505 | while ((node != &root_node) && list_empty(&node->children)) { | |
506 | parent = node->parent; | |
507 | release_node(node); | |
508 | node = parent; | |
509 | } | |
510 | } | |
511 | ||
512 | /* | |
513 | * Find child node with given basename. Needs to be called with node_lock | |
514 | * held. | |
515 | */ | |
516 | static struct gcov_node *get_child_by_name(struct gcov_node *parent, | |
517 | const char *name) | |
518 | { | |
519 | struct gcov_node *node; | |
520 | ||
521 | list_for_each_entry(node, &parent->children, list) { | |
522 | if (strcmp(node->name, name) == 0) | |
523 | return node; | |
524 | } | |
525 | ||
526 | return NULL; | |
527 | } | |
528 | ||
529 | /* | |
530 | * write() implementation for reset file. Reset all profiling data to zero | |
85a0fdfd | 531 | * and remove nodes for which all associated object files are unloaded. |
2521f2c2 PO |
532 | */ |
533 | static ssize_t reset_write(struct file *file, const char __user *addr, | |
534 | size_t len, loff_t *pos) | |
535 | { | |
536 | struct gcov_node *node; | |
537 | ||
538 | mutex_lock(&node_lock); | |
539 | restart: | |
540 | list_for_each_entry(node, &all_head, all) { | |
85a0fdfd PO |
541 | if (node->num_loaded > 0) |
542 | reset_node(node); | |
2521f2c2 PO |
543 | else if (list_empty(&node->children)) { |
544 | remove_node(node); | |
545 | /* Several nodes may have gone - restart loop. */ | |
546 | goto restart; | |
547 | } | |
548 | } | |
549 | mutex_unlock(&node_lock); | |
550 | ||
551 | return len; | |
552 | } | |
553 | ||
554 | /* read() implementation for reset file. Unused. */ | |
555 | static ssize_t reset_read(struct file *file, char __user *addr, size_t len, | |
556 | loff_t *pos) | |
557 | { | |
558 | /* Allow read operation so that a recursive copy won't fail. */ | |
559 | return 0; | |
560 | } | |
561 | ||
562 | static const struct file_operations gcov_reset_fops = { | |
563 | .write = reset_write, | |
564 | .read = reset_read, | |
6038f373 | 565 | .llseek = noop_llseek, |
2521f2c2 PO |
566 | }; |
567 | ||
568 | /* | |
569 | * Create a node for a given profiling data set and add it to all lists and | |
570 | * debugfs. Needs to be called with node_lock held. | |
571 | */ | |
572 | static void add_node(struct gcov_info *info) | |
573 | { | |
574 | char *filename; | |
575 | char *curr; | |
576 | char *next; | |
577 | struct gcov_node *parent; | |
578 | struct gcov_node *node; | |
579 | ||
8cbce376 | 580 | filename = kstrdup(gcov_info_filename(info), GFP_KERNEL); |
2521f2c2 PO |
581 | if (!filename) |
582 | return; | |
583 | parent = &root_node; | |
584 | /* Create directory nodes along the path. */ | |
585 | for (curr = filename; (next = strchr(curr, '/')); curr = next + 1) { | |
586 | if (curr == next) | |
587 | continue; | |
588 | *next = 0; | |
589 | if (strcmp(curr, ".") == 0) | |
590 | continue; | |
591 | if (strcmp(curr, "..") == 0) { | |
592 | if (!parent->parent) | |
593 | goto err_remove; | |
594 | parent = parent->parent; | |
595 | continue; | |
596 | } | |
597 | node = get_child_by_name(parent, curr); | |
598 | if (!node) { | |
599 | node = new_node(parent, NULL, curr); | |
600 | if (!node) | |
601 | goto err_remove; | |
602 | } | |
603 | parent = node; | |
604 | } | |
605 | /* Create file node. */ | |
606 | node = new_node(parent, info, curr); | |
607 | if (!node) | |
608 | goto err_remove; | |
609 | out: | |
610 | kfree(filename); | |
611 | return; | |
612 | ||
613 | err_remove: | |
614 | remove_node(parent); | |
615 | goto out; | |
616 | } | |
617 | ||
618 | /* | |
85a0fdfd PO |
619 | * Associate a profiling data set with an existing node. Needs to be called |
620 | * with node_lock held. | |
2521f2c2 | 621 | */ |
85a0fdfd | 622 | static void add_info(struct gcov_node *node, struct gcov_info *info) |
2521f2c2 | 623 | { |
85a0fdfd PO |
624 | struct gcov_info **loaded_info; |
625 | int num = node->num_loaded; | |
626 | ||
627 | /* | |
628 | * Prepare new array. This is done first to simplify cleanup in | |
629 | * case the new data set is incompatible, the node only contains | |
630 | * unloaded data sets and there's not enough memory for the array. | |
631 | */ | |
632 | loaded_info = kcalloc(num + 1, sizeof(struct gcov_info *), GFP_KERNEL); | |
633 | if (!loaded_info) { | |
a5ebb875 AM |
634 | pr_warn("could not add '%s' (out of memory)\n", |
635 | gcov_info_filename(info)); | |
85a0fdfd PO |
636 | return; |
637 | } | |
638 | memcpy(loaded_info, node->loaded_info, | |
639 | num * sizeof(struct gcov_info *)); | |
640 | loaded_info[num] = info; | |
641 | /* Check if the new data set is compatible. */ | |
642 | if (num == 0) { | |
643 | /* | |
644 | * A module was unloaded, modified and reloaded. The new | |
645 | * data set replaces the copy of the last one. | |
646 | */ | |
647 | if (!gcov_info_is_compatible(node->unloaded_info, info)) { | |
a5ebb875 AM |
648 | pr_warn("discarding saved data for %s " |
649 | "(incompatible version)\n", | |
650 | gcov_info_filename(info)); | |
85a0fdfd PO |
651 | gcov_info_free(node->unloaded_info); |
652 | node->unloaded_info = NULL; | |
653 | } | |
654 | } else { | |
655 | /* | |
656 | * Two different versions of the same object file are loaded. | |
657 | * The initial one takes precedence. | |
658 | */ | |
659 | if (!gcov_info_is_compatible(node->loaded_info[0], info)) { | |
a5ebb875 AM |
660 | pr_warn("could not add '%s' (incompatible " |
661 | "version)\n", gcov_info_filename(info)); | |
85a0fdfd PO |
662 | kfree(loaded_info); |
663 | return; | |
664 | } | |
2521f2c2 | 665 | } |
85a0fdfd PO |
666 | /* Overwrite previous array. */ |
667 | kfree(node->loaded_info); | |
668 | node->loaded_info = loaded_info; | |
669 | node->num_loaded = num + 1; | |
670 | } | |
2521f2c2 | 671 | |
85a0fdfd PO |
672 | /* |
673 | * Return the index of a profiling data set associated with a node. | |
674 | */ | |
675 | static int get_info_index(struct gcov_node *node, struct gcov_info *info) | |
676 | { | |
677 | int i; | |
678 | ||
679 | for (i = 0; i < node->num_loaded; i++) { | |
680 | if (node->loaded_info[i] == info) | |
681 | return i; | |
682 | } | |
683 | return -ENOENT; | |
2521f2c2 PO |
684 | } |
685 | ||
686 | /* | |
85a0fdfd | 687 | * Save the data of a profiling data set which is being unloaded. |
2521f2c2 | 688 | */ |
85a0fdfd | 689 | static void save_info(struct gcov_node *node, struct gcov_info *info) |
2521f2c2 | 690 | { |
85a0fdfd PO |
691 | if (node->unloaded_info) |
692 | gcov_info_add(node->unloaded_info, info); | |
2521f2c2 | 693 | else { |
85a0fdfd PO |
694 | node->unloaded_info = gcov_info_dup(info); |
695 | if (!node->unloaded_info) { | |
a5ebb875 AM |
696 | pr_warn("could not save data for '%s' " |
697 | "(out of memory)\n", | |
698 | gcov_info_filename(info)); | |
85a0fdfd PO |
699 | } |
700 | } | |
701 | } | |
702 | ||
703 | /* | |
704 | * Disassociate a profiling data set from a node. Needs to be called with | |
705 | * node_lock held. | |
706 | */ | |
707 | static void remove_info(struct gcov_node *node, struct gcov_info *info) | |
708 | { | |
709 | int i; | |
710 | ||
711 | i = get_info_index(node, info); | |
712 | if (i < 0) { | |
a5ebb875 AM |
713 | pr_warn("could not remove '%s' (not found)\n", |
714 | gcov_info_filename(info)); | |
85a0fdfd | 715 | return; |
2521f2c2 | 716 | } |
85a0fdfd PO |
717 | if (gcov_persist) |
718 | save_info(node, info); | |
719 | /* Shrink array. */ | |
720 | node->loaded_info[i] = node->loaded_info[node->num_loaded - 1]; | |
721 | node->num_loaded--; | |
722 | if (node->num_loaded > 0) | |
723 | return; | |
724 | /* Last loaded data set was removed. */ | |
725 | kfree(node->loaded_info); | |
726 | node->loaded_info = NULL; | |
727 | node->num_loaded = 0; | |
728 | if (!node->unloaded_info) | |
729 | remove_node(node); | |
2521f2c2 PO |
730 | } |
731 | ||
732 | /* | |
733 | * Callback to create/remove profiling files when code compiled with | |
734 | * -fprofile-arcs is loaded/unloaded. | |
735 | */ | |
736 | void gcov_event(enum gcov_action action, struct gcov_info *info) | |
737 | { | |
738 | struct gcov_node *node; | |
739 | ||
740 | mutex_lock(&node_lock); | |
8cbce376 | 741 | node = get_node_by_name(gcov_info_filename(info)); |
2521f2c2 PO |
742 | switch (action) { |
743 | case GCOV_ADD: | |
85a0fdfd PO |
744 | if (node) |
745 | add_info(node, info); | |
746 | else | |
2521f2c2 | 747 | add_node(info); |
2521f2c2 PO |
748 | break; |
749 | case GCOV_REMOVE: | |
85a0fdfd PO |
750 | if (node) |
751 | remove_info(node, info); | |
752 | else { | |
a5ebb875 AM |
753 | pr_warn("could not remove '%s' (not found)\n", |
754 | gcov_info_filename(info)); | |
2521f2c2 | 755 | } |
2521f2c2 PO |
756 | break; |
757 | } | |
758 | mutex_unlock(&node_lock); | |
759 | } | |
760 | ||
761 | /* Create debugfs entries. */ | |
762 | static __init int gcov_fs_init(void) | |
763 | { | |
764 | int rc = -EIO; | |
765 | ||
766 | init_node(&root_node, NULL, NULL, NULL); | |
767 | /* | |
768 | * /sys/kernel/debug/gcov will be parent for the reset control file | |
769 | * and all profiling files. | |
770 | */ | |
771 | root_node.dentry = debugfs_create_dir("gcov", NULL); | |
772 | if (!root_node.dentry) | |
773 | goto err_remove; | |
774 | /* | |
775 | * Create reset file which resets all profiling counts when written | |
776 | * to. | |
777 | */ | |
778 | reset_dentry = debugfs_create_file("reset", 0600, root_node.dentry, | |
779 | NULL, &gcov_reset_fops); | |
780 | if (!reset_dentry) | |
781 | goto err_remove; | |
782 | /* Replay previous events to get our fs hierarchy up-to-date. */ | |
783 | gcov_enable_events(); | |
784 | return 0; | |
785 | ||
786 | err_remove: | |
787 | pr_err("init failed\n"); | |
834b18b2 | 788 | debugfs_remove(root_node.dentry); |
2521f2c2 PO |
789 | |
790 | return rc; | |
791 | } | |
792 | device_initcall(gcov_fs_init); |