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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> | |
1391efa9 | 29 | #include <linux/mm.h> |
2521f2c2 PO |
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 | |
85a0fdfd PO |
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. | |
2521f2c2 PO |
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; | |
85a0fdfd PO |
57 | struct gcov_info **loaded_info; |
58 | struct gcov_info *unloaded_info; | |
2521f2c2 PO |
59 | struct dentry *dentry; |
60 | struct dentry **links; | |
85a0fdfd | 61 | int num_loaded; |
6524d794 | 62 | char name[]; |
2521f2c2 PO |
63 | }; |
64 | ||
65 | static const char objtree[] = OBJTREE; | |
66 | static const char srctree[] = SRCTREE; | |
67 | static struct gcov_node root_node; | |
2521f2c2 PO |
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 | ||
7a1d55b9 JB |
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; | |
7a1d55b9 JB |
100 | size_t size; |
101 | loff_t pos; | |
fbd126f5 | 102 | char buffer[] __counted_by(size); |
7a1d55b9 JB |
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; | |
3180c44f JB |
114 | size_t size; |
115 | ||
116 | /* Dry-run to get the actual buffer size. */ | |
117 | size = convert_to_gcda(NULL, info); | |
7a1d55b9 | 118 | |
1391efa9 | 119 | iter = kvmalloc(struct_size(iter, buffer, size), GFP_KERNEL); |
7a1d55b9 | 120 | if (!iter) |
3180c44f | 121 | return NULL; |
7a1d55b9 JB |
122 | |
123 | iter->info = info; | |
3180c44f | 124 | iter->size = size; |
7a1d55b9 JB |
125 | convert_to_gcda(iter->buffer, info); |
126 | ||
127 | return iter; | |
7a1d55b9 JB |
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 | { | |
1391efa9 | 137 | kvfree(iter); |
7a1d55b9 JB |
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, iter->buffer + iter->pos, len); | |
194 | ||
195 | return 0; | |
196 | } | |
197 | ||
2521f2c2 PO |
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(seq->private); | |
209 | for (i = 0; i < *pos; i++) { | |
210 | if (gcov_iter_next(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 | ||
f4d74ef6 | 221 | (*pos)++; |
2521f2c2 PO |
222 | if (gcov_iter_next(iter)) |
223 | return NULL; | |
2521f2c2 PO |
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 | /* | |
85a0fdfd PO |
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. | |
2521f2c2 PO |
254 | */ |
255 | static struct gcov_info *get_node_info(struct gcov_node *node) | |
256 | { | |
85a0fdfd PO |
257 | if (node->num_loaded > 0) |
258 | return node->loaded_info[0]; | |
2521f2c2 | 259 | |
85a0fdfd PO |
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(node->unloaded_info); | |
274 | else | |
275 | info = gcov_info_dup(node->loaded_info[i++]); | |
276 | if (!info) | |
277 | return NULL; | |
278 | for (; i < node->num_loaded; i++) | |
279 | gcov_info_add(info, node->loaded_info[i]); | |
280 | ||
281 | return info; | |
2521f2c2 PO |
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 | |
85a0fdfd PO |
299 | * complexity and concurrent access and to keep accumulating multiple |
300 | * profiling data sets associated with one node simple. | |
2521f2c2 | 301 | */ |
85a0fdfd | 302 | info = get_accumulated_info(node); |
2521f2c2 PO |
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(&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); | |
8cbce376 | 355 | if (info && (strcmp(gcov_info_filename(info), name) == 0)) |
2521f2c2 PO |
356 | return node; |
357 | } | |
358 | ||
359 | return NULL; | |
360 | } | |
361 | ||
85a0fdfd PO |
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(node->unloaded_info); | |
371 | for (i = 0; i < node->num_loaded; i++) | |
372 | gcov_info_reset(node->loaded_info[i]); | |
373 | } | |
374 | ||
2521f2c2 PO |
375 | static void remove_node(struct gcov_node *node); |
376 | ||
377 | /* | |
378 | * write() implementation for gcov data files. Reset profiling data for the | |
85a0fdfd PO |
379 | * corresponding file. If all associated object files have been unloaded, |
380 | * remove the debug fs node as well. | |
2521f2c2 PO |
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(seq->private); | |
391 | mutex_lock(&node_lock); | |
8cbce376 | 392 | node = get_node_by_name(gcov_info_filename(info)); |
2521f2c2 PO |
393 | if (node) { |
394 | /* Reset counts or remove node for unloaded modules. */ | |
85a0fdfd | 395 | if (node->num_loaded == 0) |
2521f2c2 PO |
396 | remove_node(node); |
397 | else | |
85a0fdfd | 398 | reset_node(node); |
2521f2c2 PO |
399 | } |
400 | /* Reset counts for open file. */ | |
401 | gcov_info_reset(info); | |
402 | mutex_unlock(&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(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, "%s/%s.%s", dir, copy, ext); | |
427 | else | |
428 | target = kasprintf(GFP_KERNEL, "%s.%s", copy, ext); | |
429 | kfree(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(srctree, rel, ext->ext); | |
449 | else | |
450 | result = link_target(objtree, rel, ext->ext); | |
451 | } else { | |
452 | /* External compilation. */ | |
453 | result = link_target(NULL, filename, 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 | { | |
1931d433 | 478 | const char *basename; |
2521f2c2 PO |
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(num, sizeof(struct dentry *), GFP_KERNEL); | |
486 | if (!node->links) | |
487 | return; | |
488 | for (i = 0; i < num; i++) { | |
8cbce376 FH |
489 | target = get_link_target( |
490 | gcov_info_filename(get_node_info(node)), | |
491 | &gcov_link[i]); | |
2521f2c2 PO |
492 | if (!target) |
493 | goto out_err; | |
1931d433 AS |
494 | basename = kbasename(target); |
495 | if (basename == target) | |
2521f2c2 | 496 | goto out_err; |
2521f2c2 PO |
497 | node->links[i] = debugfs_create_symlink(deskew(basename), |
498 | parent, target); | |
2521f2c2 PO |
499 | kfree(target); |
500 | } | |
501 | ||
502 | return; | |
503 | out_err: | |
504 | kfree(target); | |
505 | while (i-- > 0) | |
506 | debugfs_remove(node->links[i]); | |
507 | kfree(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(&node->list); | |
524 | INIT_LIST_HEAD(&node->children); | |
525 | INIT_LIST_HEAD(&node->all); | |
85a0fdfd PO |
526 | if (node->loaded_info) { |
527 | node->loaded_info[0] = info; | |
528 | node->num_loaded = 1; | |
529 | } | |
2521f2c2 PO |
530 | node->parent = parent; |
531 | if (name) | |
532 | strcpy(node->name, 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(sizeof(struct gcov_node) + strlen(name) + 1, GFP_KERNEL); | |
85a0fdfd PO |
545 | if (!node) |
546 | goto err_nomem; | |
547 | if (info) { | |
548 | node->loaded_info = kcalloc(1, sizeof(struct gcov_info *), | |
549 | GFP_KERNEL); | |
550 | if (!node->loaded_info) | |
551 | goto err_nomem; | |
2521f2c2 PO |
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(deskew(node->name), 0600, | |
557 | parent->dentry, node, &gcov_data_fops); | |
558 | } else | |
559 | node->dentry = debugfs_create_dir(node->name, parent->dentry); | |
2521f2c2 PO |
560 | if (info) |
561 | add_links(node, parent->dentry); | |
562 | list_add(&node->list, &parent->children); | |
563 | list_add(&node->all, &all_head); | |
564 | ||
565 | return node; | |
85a0fdfd PO |
566 | |
567 | err_nomem: | |
568 | kfree(node); | |
a5ebb875 | 569 | pr_warn("out of memory\n"); |
85a0fdfd | 570 | return NULL; |
2521f2c2 PO |
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(node->links[i]); | |
582 | kfree(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(&node->list); | |
593 | list_del(&node->all); | |
594 | debugfs_remove(node->dentry); | |
595 | remove_links(node); | |
85a0fdfd PO |
596 | kfree(node->loaded_info); |
597 | if (node->unloaded_info) | |
598 | gcov_info_free(node->unloaded_info); | |
2521f2c2 PO |
599 | kfree(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(&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 | |
85a0fdfd | 633 | * and remove nodes for which all associated object files are unloaded. |
2521f2c2 PO |
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) { | |
85a0fdfd PO |
643 | if (node->num_loaded > 0) |
644 | reset_node(node); | |
2521f2c2 PO |
645 | else if (list_empty(&node->children)) { |
646 | remove_node(node); | |
647 | /* Several nodes may have gone - restart loop. */ | |
648 | goto restart; | |
649 | } | |
650 | } | |
651 | mutex_unlock(&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, | |
6038f373 | 667 | .llseek = noop_llseek, |
2521f2c2 PO |
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 | ||
8cbce376 | 682 | filename = kstrdup(gcov_info_filename(info), GFP_KERNEL); |
2521f2c2 PO |
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, curr); | |
700 | if (!node) { | |
701 | node = new_node(parent, NULL, curr); | |
702 | if (!node) | |
703 | goto err_remove; | |
704 | } | |
705 | parent = node; | |
706 | } | |
707 | /* Create file node. */ | |
708 | node = new_node(parent, info, curr); | |
709 | if (!node) | |
710 | goto err_remove; | |
711 | out: | |
712 | kfree(filename); | |
713 | return; | |
714 | ||
715 | err_remove: | |
716 | remove_node(parent); | |
717 | goto out; | |
718 | } | |
719 | ||
720 | /* | |
85a0fdfd PO |
721 | * Associate a profiling data set with an existing node. Needs to be called |
722 | * with node_lock held. | |
2521f2c2 | 723 | */ |
85a0fdfd | 724 | static void add_info(struct gcov_node *node, struct gcov_info *info) |
2521f2c2 | 725 | { |
85a0fdfd PO |
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(num + 1, sizeof(struct gcov_info *), GFP_KERNEL); | |
735 | if (!loaded_info) { | |
a5ebb875 AM |
736 | pr_warn("could not add '%s' (out of memory)\n", |
737 | gcov_info_filename(info)); | |
85a0fdfd PO |
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(node->unloaded_info, info)) { | |
a5ebb875 AM |
750 | pr_warn("discarding saved data for %s " |
751 | "(incompatible version)\n", | |
752 | gcov_info_filename(info)); | |
85a0fdfd PO |
753 | gcov_info_free(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(node->loaded_info[0], info)) { | |
a5ebb875 AM |
762 | pr_warn("could not add '%s' (incompatible " |
763 | "version)\n", gcov_info_filename(info)); | |
85a0fdfd PO |
764 | kfree(loaded_info); |
765 | return; | |
766 | } | |
2521f2c2 | 767 | } |
85a0fdfd PO |
768 | /* Overwrite previous array. */ |
769 | kfree(node->loaded_info); | |
770 | node->loaded_info = loaded_info; | |
771 | node->num_loaded = num + 1; | |
772 | } | |
2521f2c2 | 773 | |
85a0fdfd PO |
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; | |
2521f2c2 PO |
786 | } |
787 | ||
788 | /* | |
85a0fdfd | 789 | * Save the data of a profiling data set which is being unloaded. |
2521f2c2 | 790 | */ |
85a0fdfd | 791 | static void save_info(struct gcov_node *node, struct gcov_info *info) |
2521f2c2 | 792 | { |
85a0fdfd PO |
793 | if (node->unloaded_info) |
794 | gcov_info_add(node->unloaded_info, info); | |
2521f2c2 | 795 | else { |
85a0fdfd PO |
796 | node->unloaded_info = gcov_info_dup(info); |
797 | if (!node->unloaded_info) { | |
a5ebb875 AM |
798 | pr_warn("could not save data for '%s' " |
799 | "(out of memory)\n", | |
800 | gcov_info_filename(info)); | |
85a0fdfd PO |
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) { | |
a5ebb875 AM |
815 | pr_warn("could not remove '%s' (not found)\n", |
816 | gcov_info_filename(info)); | |
85a0fdfd | 817 | return; |
2521f2c2 | 818 | } |
85a0fdfd PO |
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(node->loaded_info); | |
828 | node->loaded_info = NULL; | |
829 | node->num_loaded = 0; | |
830 | if (!node->unloaded_info) | |
831 | remove_node(node); | |
2521f2c2 PO |
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); | |
8cbce376 | 843 | node = get_node_by_name(gcov_info_filename(info)); |
2521f2c2 PO |
844 | switch (action) { |
845 | case GCOV_ADD: | |
85a0fdfd PO |
846 | if (node) |
847 | add_info(node, info); | |
848 | else | |
2521f2c2 | 849 | add_node(info); |
2521f2c2 PO |
850 | break; |
851 | case GCOV_REMOVE: | |
85a0fdfd PO |
852 | if (node) |
853 | remove_info(node, info); | |
854 | else { | |
a5ebb875 AM |
855 | pr_warn("could not remove '%s' (not found)\n", |
856 | gcov_info_filename(info)); | |
2521f2c2 | 857 | } |
2521f2c2 PO |
858 | break; |
859 | } | |
860 | mutex_unlock(&node_lock); | |
861 | } | |
862 | ||
863 | /* Create debugfs entries. */ | |
864 | static __init int gcov_fs_init(void) | |
865 | { | |
2521f2c2 PO |
866 | init_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("gcov", NULL); | |
2521f2c2 PO |
872 | /* |
873 | * Create reset file which resets all profiling counts when written | |
874 | * to. | |
875 | */ | |
1c769fc4 GKH |
876 | debugfs_create_file("reset", 0600, root_node.dentry, NULL, |
877 | &gcov_reset_fops); | |
2521f2c2 PO |
878 | /* Replay previous events to get our fs hierarchy up-to-date. */ |
879 | gcov_enable_events(); | |
880 | return 0; | |
2521f2c2 PO |
881 | } |
882 | device_initcall(gcov_fs_init); |