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68c1021b PMF |
1 | /* |
2 | * Copyright (C) 2007 Mathieu Desnoyers | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
17 | */ | |
18 | #include <linux/module.h> | |
19 | #include <linux/mutex.h> | |
20 | #include <linux/types.h> | |
21 | #include <linux/jhash.h> | |
22 | #include <linux/list.h> | |
23 | #include <linux/rcupdate.h> | |
24 | #include <linux/marker.h> | |
25 | #include <linux/err.h> | |
26 | #include <linux/slab.h> | |
27 | #include <linux/immediate.h> | |
28 | #include <linux/sched.h> | |
29 | #include <linux/uaccess.h> | |
30 | #include <linux/user_marker.h> | |
31 | #include <linux/ltt-tracer.h> | |
32 | ||
33 | extern struct marker __start___markers[]; | |
34 | extern struct marker __stop___markers[]; | |
35 | ||
36 | /* Set to 1 to enable marker debug output */ | |
37 | static const int marker_debug; | |
38 | ||
39 | /* | |
40 | * markers_mutex nests inside module_mutex. Markers mutex protects the builtin | |
41 | * and module markers and the hash table. | |
42 | */ | |
43 | static DEFINE_MUTEX(markers_mutex); | |
44 | ||
45 | void lock_markers(void) | |
46 | { | |
47 | mutex_lock(&markers_mutex); | |
48 | } | |
49 | ||
50 | void unlock_markers(void) | |
51 | { | |
52 | mutex_unlock(&markers_mutex); | |
53 | } | |
54 | ||
55 | /* | |
56 | * Marker hash table, containing the active markers. | |
57 | * Protected by module_mutex. | |
58 | */ | |
59 | #define MARKER_HASH_BITS 6 | |
60 | #define MARKER_TABLE_SIZE (1 << MARKER_HASH_BITS) | |
61 | static struct hlist_head marker_table[MARKER_TABLE_SIZE]; | |
62 | ||
63 | /* | |
64 | * Note about RCU : | |
65 | * It is used to make sure every handler has finished using its private data | |
66 | * between two consecutive operation (add or remove) on a given marker. It is | |
67 | * also used to delay the free of multiple probes array until a quiescent state | |
68 | * is reached. | |
69 | * marker entries modifications are protected by the markers_mutex. | |
70 | */ | |
71 | struct marker_entry { | |
72 | struct hlist_node hlist; | |
73 | char *format; | |
74 | char *name; | |
75 | /* Probe wrapper */ | |
76 | void (*call)(const struct marker *mdata, void *call_private, ...); | |
77 | struct marker_probe_closure single; | |
78 | struct marker_probe_closure *multi; | |
79 | int refcount; /* Number of times armed. 0 if disarmed. */ | |
80 | struct rcu_head rcu; | |
81 | void *oldptr; | |
82 | int rcu_pending; | |
83 | u16 channel_id; | |
84 | u16 event_id; | |
85 | unsigned char ptype:1; | |
86 | unsigned char format_allocated:1; | |
87 | char channel[0]; /* Contains channel'\0'name'\0'format'\0' */ | |
88 | }; | |
89 | ||
90 | #ifdef CONFIG_MARKERS_USERSPACE | |
91 | static void marker_update_processes(void); | |
92 | #else | |
93 | static void marker_update_processes(void) | |
94 | { | |
95 | } | |
96 | #endif | |
97 | ||
98 | /** | |
99 | * __mark_empty_function - Empty probe callback | |
100 | * @mdata: marker data | |
101 | * @probe_private: probe private data | |
102 | * @call_private: call site private data | |
103 | * @fmt: format string | |
104 | * @...: variable argument list | |
105 | * | |
106 | * Empty callback provided as a probe to the markers. By providing this to a | |
107 | * disabled marker, we make sure the execution flow is always valid even | |
108 | * though the function pointer change and the marker enabling are two distinct | |
109 | * operations that modifies the execution flow of preemptible code. | |
110 | */ | |
111 | notrace void __mark_empty_function(const struct marker *mdata, | |
112 | void *probe_private, void *call_private, const char *fmt, va_list *args) | |
113 | { | |
114 | } | |
115 | EXPORT_SYMBOL_GPL(__mark_empty_function); | |
116 | ||
117 | /* | |
118 | * marker_probe_cb Callback that prepares the variable argument list for probes. | |
119 | * @mdata: pointer of type struct marker | |
120 | * @call_private: caller site private data | |
121 | * @...: Variable argument list. | |
122 | * | |
123 | * Since we do not use "typical" pointer based RCU in the 1 argument case, we | |
124 | * need to put a full smp_rmb() in this branch. This is why we do not use | |
125 | * rcu_dereference() for the pointer read. | |
126 | */ | |
127 | notrace void marker_probe_cb(const struct marker *mdata, | |
128 | void *call_private, ...) | |
129 | { | |
130 | va_list args; | |
131 | char ptype; | |
132 | ||
133 | /* | |
134 | * rcu_read_lock_sched does two things : disabling preemption to make | |
135 | * sure the teardown of the callbacks can be done correctly when they | |
136 | * are in modules and they insure RCU read coherency. | |
137 | */ | |
138 | rcu_read_lock_sched_notrace(); | |
139 | ptype = mdata->ptype; | |
140 | if (likely(!ptype)) { | |
141 | marker_probe_func *func; | |
142 | /* Must read the ptype before ptr. They are not data dependant, | |
143 | * so we put an explicit smp_rmb() here. */ | |
144 | smp_rmb(); | |
145 | func = mdata->single.func; | |
146 | /* Must read the ptr before private data. They are not data | |
147 | * dependant, so we put an explicit smp_rmb() here. */ | |
148 | smp_rmb(); | |
149 | va_start(args, call_private); | |
150 | func(mdata, mdata->single.probe_private, call_private, | |
151 | mdata->format, &args); | |
152 | va_end(args); | |
153 | } else { | |
154 | struct marker_probe_closure *multi; | |
155 | int i; | |
156 | /* | |
157 | * Read mdata->ptype before mdata->multi. | |
158 | */ | |
159 | smp_rmb(); | |
160 | multi = mdata->multi; | |
161 | /* | |
162 | * multi points to an array, therefore accessing the array | |
163 | * depends on reading multi. However, even in this case, | |
164 | * we must insure that the pointer is read _before_ the array | |
165 | * data. Same as rcu_dereference, but we need a full smp_rmb() | |
166 | * in the fast path, so put the explicit barrier here. | |
167 | */ | |
168 | smp_read_barrier_depends(); | |
169 | for (i = 0; multi[i].func; i++) { | |
170 | va_start(args, call_private); | |
171 | multi[i].func(mdata, multi[i].probe_private, | |
172 | call_private, mdata->format, &args); | |
173 | va_end(args); | |
174 | } | |
175 | } | |
176 | rcu_read_unlock_sched_notrace(); | |
177 | } | |
178 | EXPORT_SYMBOL_GPL(marker_probe_cb); | |
179 | ||
180 | /* | |
181 | * marker_probe_cb Callback that does not prepare the variable argument list. | |
182 | * @mdata: pointer of type struct marker | |
183 | * @call_private: caller site private data | |
184 | * @...: Variable argument list. | |
185 | * | |
186 | * Should be connected to markers "MARK_NOARGS". | |
187 | */ | |
188 | static notrace void marker_probe_cb_noarg(const struct marker *mdata, | |
189 | void *call_private, ...) | |
190 | { | |
191 | va_list args; /* not initialized */ | |
192 | char ptype; | |
193 | ||
194 | rcu_read_lock_sched_notrace(); | |
195 | ptype = mdata->ptype; | |
196 | if (likely(!ptype)) { | |
197 | marker_probe_func *func; | |
198 | /* Must read the ptype before ptr. They are not data dependant, | |
199 | * so we put an explicit smp_rmb() here. */ | |
200 | smp_rmb(); | |
201 | func = mdata->single.func; | |
202 | /* Must read the ptr before private data. They are not data | |
203 | * dependant, so we put an explicit smp_rmb() here. */ | |
204 | smp_rmb(); | |
205 | func(mdata, mdata->single.probe_private, call_private, | |
206 | mdata->format, &args); | |
207 | } else { | |
208 | struct marker_probe_closure *multi; | |
209 | int i; | |
210 | /* | |
211 | * Read mdata->ptype before mdata->multi. | |
212 | */ | |
213 | smp_rmb(); | |
214 | multi = mdata->multi; | |
215 | /* | |
216 | * multi points to an array, therefore accessing the array | |
217 | * depends on reading multi. However, even in this case, | |
218 | * we must insure that the pointer is read _before_ the array | |
219 | * data. Same as rcu_dereference, but we need a full smp_rmb() | |
220 | * in the fast path, so put the explicit barrier here. | |
221 | */ | |
222 | smp_read_barrier_depends(); | |
223 | for (i = 0; multi[i].func; i++) | |
224 | multi[i].func(mdata, multi[i].probe_private, | |
225 | call_private, mdata->format, &args); | |
226 | } | |
227 | rcu_read_unlock_sched_notrace(); | |
228 | } | |
229 | ||
230 | static void free_old_closure(struct rcu_head *head) | |
231 | { | |
232 | struct marker_entry *entry = container_of(head, | |
233 | struct marker_entry, rcu); | |
234 | kfree(entry->oldptr); | |
235 | /* Make sure we free the data before setting the pending flag to 0 */ | |
236 | smp_wmb(); | |
237 | entry->rcu_pending = 0; | |
238 | } | |
239 | ||
240 | static void debug_print_probes(struct marker_entry *entry) | |
241 | { | |
242 | int i; | |
243 | ||
244 | if (!marker_debug) | |
245 | return; | |
246 | ||
247 | if (!entry->ptype) { | |
248 | printk(KERN_DEBUG "Single probe : %p %p\n", | |
249 | entry->single.func, | |
250 | entry->single.probe_private); | |
251 | } else { | |
252 | for (i = 0; entry->multi[i].func; i++) | |
253 | printk(KERN_DEBUG "Multi probe %d : %p %p\n", i, | |
254 | entry->multi[i].func, | |
255 | entry->multi[i].probe_private); | |
256 | } | |
257 | } | |
258 | ||
259 | static struct marker_probe_closure * | |
260 | marker_entry_add_probe(struct marker_entry *entry, | |
261 | marker_probe_func *probe, void *probe_private) | |
262 | { | |
263 | int nr_probes = 0; | |
264 | struct marker_probe_closure *old, *new; | |
265 | ||
266 | WARN_ON(!probe); | |
267 | ||
268 | debug_print_probes(entry); | |
269 | old = entry->multi; | |
270 | if (!entry->ptype) { | |
271 | if (entry->single.func == probe && | |
272 | entry->single.probe_private == probe_private) | |
273 | return ERR_PTR(-EBUSY); | |
274 | if (entry->single.func == __mark_empty_function) { | |
275 | /* 0 -> 1 probes */ | |
276 | entry->single.func = probe; | |
277 | entry->single.probe_private = probe_private; | |
278 | entry->refcount = 1; | |
279 | entry->ptype = 0; | |
280 | debug_print_probes(entry); | |
281 | return NULL; | |
282 | } else { | |
283 | /* 1 -> 2 probes */ | |
284 | nr_probes = 1; | |
285 | old = NULL; | |
286 | } | |
287 | } else { | |
288 | /* (N -> N+1), (N != 0, 1) probes */ | |
289 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) | |
290 | if (old[nr_probes].func == probe | |
291 | && old[nr_probes].probe_private | |
292 | == probe_private) | |
293 | return ERR_PTR(-EBUSY); | |
294 | } | |
295 | /* + 2 : one for new probe, one for NULL func */ | |
296 | new = kzalloc((nr_probes + 2) * sizeof(struct marker_probe_closure), | |
297 | GFP_KERNEL); | |
298 | if (new == NULL) | |
299 | return ERR_PTR(-ENOMEM); | |
300 | if (!old) | |
301 | new[0] = entry->single; | |
302 | else | |
303 | memcpy(new, old, | |
304 | nr_probes * sizeof(struct marker_probe_closure)); | |
305 | new[nr_probes].func = probe; | |
306 | new[nr_probes].probe_private = probe_private; | |
307 | entry->refcount = nr_probes + 1; | |
308 | entry->multi = new; | |
309 | entry->ptype = 1; | |
310 | debug_print_probes(entry); | |
311 | return old; | |
312 | } | |
313 | ||
314 | static struct marker_probe_closure * | |
315 | marker_entry_remove_probe(struct marker_entry *entry, | |
316 | marker_probe_func *probe, void *probe_private) | |
317 | { | |
318 | int nr_probes = 0, nr_del = 0, i; | |
319 | struct marker_probe_closure *old, *new; | |
320 | ||
321 | old = entry->multi; | |
322 | ||
323 | debug_print_probes(entry); | |
324 | if (!entry->ptype) { | |
325 | /* 0 -> N is an error */ | |
326 | WARN_ON(entry->single.func == __mark_empty_function); | |
327 | /* 1 -> 0 probes */ | |
328 | WARN_ON(probe && entry->single.func != probe); | |
329 | WARN_ON(entry->single.probe_private != probe_private); | |
330 | entry->single.func = __mark_empty_function; | |
331 | entry->refcount = 0; | |
332 | entry->ptype = 0; | |
333 | debug_print_probes(entry); | |
334 | return NULL; | |
335 | } else { | |
336 | /* (N -> M), (N > 1, M >= 0) probes */ | |
337 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { | |
338 | if ((!probe || old[nr_probes].func == probe) | |
339 | && old[nr_probes].probe_private | |
340 | == probe_private) | |
341 | nr_del++; | |
342 | } | |
343 | } | |
344 | ||
345 | if (nr_probes - nr_del == 0) { | |
346 | /* N -> 0, (N > 1) */ | |
347 | entry->single.func = __mark_empty_function; | |
348 | entry->refcount = 0; | |
349 | entry->ptype = 0; | |
350 | } else if (nr_probes - nr_del == 1) { | |
351 | /* N -> 1, (N > 1) */ | |
352 | for (i = 0; old[i].func; i++) | |
353 | if ((probe && old[i].func != probe) || | |
354 | old[i].probe_private != probe_private) | |
355 | entry->single = old[i]; | |
356 | entry->refcount = 1; | |
357 | entry->ptype = 0; | |
358 | } else { | |
359 | int j = 0; | |
360 | /* N -> M, (N > 1, M > 1) */ | |
361 | /* + 1 for NULL */ | |
362 | new = kzalloc((nr_probes - nr_del + 1) | |
363 | * sizeof(struct marker_probe_closure), GFP_KERNEL); | |
364 | if (new == NULL) | |
365 | return ERR_PTR(-ENOMEM); | |
366 | for (i = 0; old[i].func; i++) | |
367 | if ((probe && old[i].func != probe) || | |
368 | old[i].probe_private != probe_private) | |
369 | new[j++] = old[i]; | |
370 | entry->refcount = nr_probes - nr_del; | |
371 | entry->ptype = 1; | |
372 | entry->multi = new; | |
373 | } | |
374 | debug_print_probes(entry); | |
375 | return old; | |
376 | } | |
377 | ||
378 | /* | |
379 | * Get marker if the marker is present in the marker hash table. | |
380 | * Must be called with markers_mutex held. | |
381 | * Returns NULL if not present. | |
382 | */ | |
383 | static struct marker_entry *get_marker(const char *channel, const char *name) | |
384 | { | |
385 | struct hlist_head *head; | |
386 | struct hlist_node *node; | |
387 | struct marker_entry *e; | |
388 | size_t channel_len = strlen(channel) + 1; | |
389 | size_t name_len = strlen(name) + 1; | |
390 | u32 hash; | |
391 | ||
392 | hash = jhash(channel, channel_len-1, 0) ^ jhash(name, name_len-1, 0); | |
393 | head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)]; | |
394 | hlist_for_each_entry(e, node, head, hlist) { | |
395 | if (!strcmp(channel, e->channel) && !strcmp(name, e->name)) | |
396 | return e; | |
397 | } | |
398 | return NULL; | |
399 | } | |
400 | ||
401 | /* | |
402 | * Add the marker to the marker hash table. Must be called with markers_mutex | |
403 | * held. | |
404 | */ | |
405 | static struct marker_entry *add_marker(const char *channel, const char *name, | |
406 | const char *format) | |
407 | { | |
408 | struct hlist_head *head; | |
409 | struct hlist_node *node; | |
410 | struct marker_entry *e; | |
411 | size_t channel_len = strlen(channel) + 1; | |
412 | size_t name_len = strlen(name) + 1; | |
413 | size_t format_len = 0; | |
414 | u32 hash; | |
415 | ||
416 | hash = jhash(channel, channel_len-1, 0) ^ jhash(name, name_len-1, 0); | |
417 | if (format) | |
418 | format_len = strlen(format) + 1; | |
419 | head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)]; | |
420 | hlist_for_each_entry(e, node, head, hlist) { | |
421 | if (!strcmp(channel, e->channel) && !strcmp(name, e->name)) { | |
422 | printk(KERN_NOTICE | |
423 | "Marker %s.%s busy\n", channel, name); | |
424 | return ERR_PTR(-EBUSY); /* Already there */ | |
425 | } | |
426 | } | |
427 | /* | |
428 | * Using kmalloc here to allocate a variable length element. Could | |
429 | * cause some memory fragmentation if overused. | |
430 | */ | |
431 | e = kmalloc(sizeof(struct marker_entry) | |
432 | + channel_len + name_len + format_len, | |
433 | GFP_KERNEL); | |
434 | if (!e) | |
435 | return ERR_PTR(-ENOMEM); | |
436 | memcpy(e->channel, channel, channel_len); | |
437 | e->name = &e->channel[channel_len]; | |
438 | memcpy(e->name, name, name_len); | |
439 | if (format) { | |
440 | e->format = &e->name[channel_len + name_len]; | |
441 | memcpy(e->format, format, format_len); | |
442 | if (strcmp(e->format, MARK_NOARGS) == 0) | |
443 | e->call = marker_probe_cb_noarg; | |
444 | else | |
445 | e->call = marker_probe_cb; | |
446 | trace_mark(metadata, core_marker_format, | |
447 | "channel %s name %s format %s", | |
448 | e->channel, e->name, e->format); | |
449 | } else { | |
450 | e->format = NULL; | |
451 | e->call = marker_probe_cb; | |
452 | } | |
453 | e->single.func = __mark_empty_function; | |
454 | e->single.probe_private = NULL; | |
455 | e->multi = NULL; | |
456 | e->ptype = 0; | |
457 | e->format_allocated = 0; | |
458 | e->refcount = 0; | |
459 | e->rcu_pending = 0; | |
460 | hlist_add_head(&e->hlist, head); | |
461 | return e; | |
462 | } | |
463 | ||
464 | /* | |
465 | * Remove the marker from the marker hash table. Must be called with mutex_lock | |
466 | * held. | |
467 | */ | |
468 | static int remove_marker(const char *channel, const char *name) | |
469 | { | |
470 | struct hlist_head *head; | |
471 | struct hlist_node *node; | |
472 | struct marker_entry *e; | |
473 | int found = 0; | |
474 | size_t channel_len = strlen(channel) + 1; | |
475 | size_t name_len = strlen(name) + 1; | |
476 | u32 hash; | |
477 | int ret; | |
478 | ||
479 | hash = jhash(channel, channel_len-1, 0) ^ jhash(name, name_len-1, 0); | |
480 | head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)]; | |
481 | hlist_for_each_entry(e, node, head, hlist) { | |
482 | if (!strcmp(channel, e->channel) && !strcmp(name, e->name)) { | |
483 | found = 1; | |
484 | break; | |
485 | } | |
486 | } | |
487 | if (!found) | |
488 | return -ENOENT; | |
489 | if (e->single.func != __mark_empty_function) | |
490 | return -EBUSY; | |
491 | hlist_del(&e->hlist); | |
492 | if (e->format_allocated) | |
493 | kfree(e->format); | |
494 | ret = ltt_channels_unregister(e->channel); | |
495 | WARN_ON(ret); | |
496 | /* Make sure the call_rcu has been executed */ | |
497 | if (e->rcu_pending) | |
498 | rcu_barrier_sched(); | |
499 | kfree(e); | |
500 | return 0; | |
501 | } | |
502 | ||
503 | /* | |
504 | * Set the mark_entry format to the format found in the element. | |
505 | */ | |
506 | static int marker_set_format(struct marker_entry *entry, const char *format) | |
507 | { | |
508 | entry->format = kstrdup(format, GFP_KERNEL); | |
509 | if (!entry->format) | |
510 | return -ENOMEM; | |
511 | entry->format_allocated = 1; | |
512 | ||
513 | trace_mark(metadata, core_marker_format, | |
514 | "channel %s name %s format %s", | |
515 | entry->channel, entry->name, entry->format); | |
516 | return 0; | |
517 | } | |
518 | ||
519 | /* | |
520 | * Sets the probe callback corresponding to one marker. | |
521 | */ | |
522 | static int set_marker(struct marker_entry *entry, struct marker *elem, | |
523 | int active) | |
524 | { | |
525 | int ret = 0; | |
526 | WARN_ON(strcmp(entry->name, elem->name) != 0); | |
527 | ||
528 | if (entry->format) { | |
529 | if (strcmp(entry->format, elem->format) != 0) { | |
530 | printk(KERN_NOTICE | |
531 | "Format mismatch for probe %s " | |
532 | "(%s), marker (%s)\n", | |
533 | entry->name, | |
534 | entry->format, | |
535 | elem->format); | |
536 | return -EPERM; | |
537 | } | |
538 | } else { | |
539 | ret = marker_set_format(entry, elem->format); | |
540 | if (ret) | |
541 | return ret; | |
542 | } | |
543 | ||
544 | /* | |
545 | * probe_cb setup (statically known) is done here. It is | |
546 | * asynchronous with the rest of execution, therefore we only | |
547 | * pass from a "safe" callback (with argument) to an "unsafe" | |
548 | * callback (does not set arguments). | |
549 | */ | |
550 | elem->call = entry->call; | |
551 | elem->channel_id = entry->channel_id; | |
552 | elem->event_id = entry->event_id; | |
553 | /* | |
554 | * Sanity check : | |
555 | * We only update the single probe private data when the ptr is | |
556 | * set to a _non_ single probe! (0 -> 1 and N -> 1, N != 1) | |
557 | */ | |
558 | WARN_ON(elem->single.func != __mark_empty_function | |
559 | && elem->single.probe_private != entry->single.probe_private | |
560 | && !elem->ptype); | |
561 | elem->single.probe_private = entry->single.probe_private; | |
562 | /* | |
563 | * Make sure the private data is valid when we update the | |
564 | * single probe ptr. | |
565 | */ | |
566 | smp_wmb(); | |
567 | elem->single.func = entry->single.func; | |
568 | /* | |
569 | * We also make sure that the new probe callbacks array is consistent | |
570 | * before setting a pointer to it. | |
571 | */ | |
572 | rcu_assign_pointer(elem->multi, entry->multi); | |
573 | /* | |
574 | * Update the function or multi probe array pointer before setting the | |
575 | * ptype. | |
576 | */ | |
577 | smp_wmb(); | |
578 | elem->ptype = entry->ptype; | |
579 | ||
580 | if (elem->tp_name && (active ^ _imv_read(elem->state))) { | |
581 | WARN_ON(!elem->tp_cb); | |
582 | /* | |
583 | * It is ok to directly call the probe registration because type | |
584 | * checking has been done in the __trace_mark_tp() macro. | |
585 | */ | |
586 | ||
587 | if (active) { | |
588 | /* | |
589 | * try_module_get should always succeed because we hold | |
590 | * markers_mutex to get the tp_cb address. | |
591 | */ | |
592 | ret = try_module_get(__module_text_address( | |
593 | (unsigned long)elem->tp_cb)); | |
594 | BUG_ON(!ret); | |
595 | ret = tracepoint_probe_register_noupdate( | |
596 | elem->tp_name, | |
597 | elem->tp_cb); | |
598 | } else { | |
599 | ret = tracepoint_probe_unregister_noupdate( | |
600 | elem->tp_name, | |
601 | elem->tp_cb); | |
602 | /* | |
603 | * tracepoint_probe_update_all() must be called | |
604 | * before the module containing tp_cb is unloaded. | |
605 | */ | |
606 | module_put(__module_text_address( | |
607 | (unsigned long)elem->tp_cb)); | |
608 | } | |
609 | } | |
610 | elem->state__imv = active; | |
611 | ||
612 | return ret; | |
613 | } | |
614 | ||
615 | /* | |
616 | * Disable a marker and its probe callback. | |
617 | * Note: only waiting an RCU period after setting elem->call to the empty | |
618 | * function insures that the original callback is not used anymore. This insured | |
619 | * by rcu_read_lock_sched around the call site. | |
620 | */ | |
621 | static void disable_marker(struct marker *elem) | |
622 | { | |
623 | int ret; | |
624 | ||
625 | /* leave "call" as is. It is known statically. */ | |
626 | if (elem->tp_name && _imv_read(elem->state)) { | |
627 | WARN_ON(!elem->tp_cb); | |
628 | /* | |
629 | * It is ok to directly call the probe registration because type | |
630 | * checking has been done in the __trace_mark_tp() macro. | |
631 | */ | |
632 | ret = tracepoint_probe_unregister_noupdate(elem->tp_name, | |
633 | elem->tp_cb); | |
634 | WARN_ON(ret); | |
635 | /* | |
636 | * tracepoint_probe_update_all() must be called | |
637 | * before the module containing tp_cb is unloaded. | |
638 | */ | |
639 | module_put(__module_text_address((unsigned long)elem->tp_cb)); | |
640 | } | |
641 | elem->state__imv = 0; | |
642 | elem->single.func = __mark_empty_function; | |
643 | /* Update the function before setting the ptype */ | |
644 | smp_wmb(); | |
645 | elem->ptype = 0; /* single probe */ | |
646 | /* | |
647 | * Leave the private data and channel_id/event_id there, because removal | |
648 | * is racy and should be done only after an RCU period. These are never | |
649 | * used until the next initialization anyway. | |
650 | */ | |
651 | } | |
652 | ||
653 | /** | |
654 | * marker_update_probe_range - Update a probe range | |
655 | * @begin: beginning of the range | |
656 | * @end: end of the range | |
657 | * | |
658 | * Updates the probe callback corresponding to a range of markers. | |
659 | */ | |
660 | void marker_update_probe_range(struct marker *begin, | |
661 | struct marker *end) | |
662 | { | |
663 | struct marker *iter; | |
664 | struct marker_entry *mark_entry; | |
665 | ||
666 | mutex_lock(&markers_mutex); | |
667 | for (iter = begin; iter < end; iter++) { | |
668 | mark_entry = get_marker(iter->channel, iter->name); | |
669 | if (mark_entry) { | |
670 | set_marker(mark_entry, iter, !!mark_entry->refcount); | |
671 | /* | |
672 | * ignore error, continue | |
673 | */ | |
674 | } else { | |
675 | disable_marker(iter); | |
676 | } | |
677 | } | |
678 | mutex_unlock(&markers_mutex); | |
679 | } | |
680 | ||
681 | /* | |
682 | * Update probes, removing the faulty probes. | |
683 | * | |
684 | * Internal callback only changed before the first probe is connected to it. | |
685 | * Single probe private data can only be changed on 0 -> 1 and 2 -> 1 | |
686 | * transitions. All other transitions will leave the old private data valid. | |
687 | * This makes the non-atomicity of the callback/private data updates valid. | |
688 | * | |
689 | * "special case" updates : | |
690 | * 0 -> 1 callback | |
691 | * 1 -> 0 callback | |
692 | * 1 -> 2 callbacks | |
693 | * 2 -> 1 callbacks | |
694 | * Other updates all behave the same, just like the 2 -> 3 or 3 -> 2 updates. | |
695 | * Site effect : marker_set_format may delete the marker entry (creating a | |
696 | * replacement). | |
697 | */ | |
698 | static void marker_update_probes(void) | |
699 | { | |
700 | /* Core kernel markers */ | |
701 | marker_update_probe_range(__start___markers, __stop___markers); | |
702 | /* Markers in modules. */ | |
703 | module_update_markers(); | |
704 | tracepoint_probe_update_all(); | |
705 | /* Update immediate values */ | |
706 | core_imv_update(); | |
707 | module_imv_update(); | |
708 | marker_update_processes(); | |
709 | } | |
710 | ||
711 | /** | |
712 | * marker_probe_register - Connect a probe to a marker | |
713 | * @channel: marker channel | |
714 | * @name: marker name | |
715 | * @format: format string | |
716 | * @probe: probe handler | |
717 | * @probe_private: probe private data | |
718 | * | |
719 | * private data must be a valid allocated memory address, or NULL. | |
720 | * Returns 0 if ok, error value on error. | |
721 | * The probe address must at least be aligned on the architecture pointer size. | |
722 | */ | |
723 | int marker_probe_register(const char *channel, const char *name, | |
724 | const char *format, marker_probe_func *probe, | |
725 | void *probe_private) | |
726 | { | |
727 | struct marker_entry *entry; | |
728 | int ret = 0, ret_err; | |
729 | struct marker_probe_closure *old; | |
730 | int first_probe = 0; | |
731 | ||
732 | mutex_lock(&markers_mutex); | |
733 | entry = get_marker(channel, name); | |
734 | if (!entry) { | |
735 | first_probe = 1; | |
736 | entry = add_marker(channel, name, format); | |
737 | if (IS_ERR(entry)) | |
738 | ret = PTR_ERR(entry); | |
739 | if (ret) | |
740 | goto end; | |
741 | ret = ltt_channels_register(channel); | |
742 | if (ret) | |
743 | goto error_remove_marker; | |
744 | ret = ltt_channels_get_index_from_name(channel); | |
745 | if (ret < 0) | |
746 | goto error_unregister_channel; | |
747 | entry->channel_id = ret; | |
748 | ret = ltt_channels_get_event_id(channel, name); | |
749 | if (ret < 0) | |
750 | goto error_unregister_channel; | |
751 | entry->event_id = ret; | |
752 | ret = 0; | |
753 | trace_mark(metadata, core_marker_id, | |
754 | "channel %s name %s event_id %hu " | |
755 | "int #1u%zu long #1u%zu pointer #1u%zu " | |
756 | "size_t #1u%zu alignment #1u%u", | |
757 | channel, name, entry->event_id, | |
758 | sizeof(int), sizeof(long), sizeof(void *), | |
759 | sizeof(size_t), ltt_get_alignment()); | |
760 | } else if (format) { | |
761 | if (!entry->format) | |
762 | ret = marker_set_format(entry, format); | |
763 | else if (strcmp(entry->format, format)) | |
764 | ret = -EPERM; | |
765 | if (ret) | |
766 | goto end; | |
767 | } | |
768 | ||
769 | /* | |
770 | * If we detect that a call_rcu is pending for this marker, | |
771 | * make sure it's executed now. | |
772 | */ | |
773 | if (entry->rcu_pending) | |
774 | rcu_barrier_sched(); | |
775 | old = marker_entry_add_probe(entry, probe, probe_private); | |
776 | if (IS_ERR(old)) { | |
777 | ret = PTR_ERR(old); | |
778 | if (first_probe) | |
779 | goto error_unregister_channel; | |
780 | else | |
781 | goto end; | |
782 | } | |
783 | mutex_unlock(&markers_mutex); | |
784 | ||
785 | marker_update_probes(); | |
786 | ||
787 | mutex_lock(&markers_mutex); | |
788 | entry = get_marker(channel, name); | |
789 | if (!entry) | |
790 | goto end; | |
791 | if (entry->rcu_pending) | |
792 | rcu_barrier_sched(); | |
793 | entry->oldptr = old; | |
794 | entry->rcu_pending = 1; | |
795 | /* write rcu_pending before calling the RCU callback */ | |
796 | smp_wmb(); | |
797 | call_rcu_sched(&entry->rcu, free_old_closure); | |
798 | goto end; | |
799 | ||
800 | error_unregister_channel: | |
801 | ret_err = ltt_channels_unregister(channel); | |
802 | WARN_ON(ret_err); | |
803 | error_remove_marker: | |
804 | ret_err = remove_marker(channel, name); | |
805 | WARN_ON(ret_err); | |
806 | end: | |
807 | mutex_unlock(&markers_mutex); | |
808 | return ret; | |
809 | } | |
810 | EXPORT_SYMBOL_GPL(marker_probe_register); | |
811 | ||
812 | /** | |
813 | * marker_probe_unregister - Disconnect a probe from a marker | |
814 | * @channel: marker channel | |
815 | * @name: marker name | |
816 | * @probe: probe function pointer | |
817 | * @probe_private: probe private data | |
818 | * | |
819 | * Returns the private data given to marker_probe_register, or an ERR_PTR(). | |
820 | * We do not need to call a synchronize_sched to make sure the probes have | |
821 | * finished running before doing a module unload, because the module unload | |
822 | * itself uses stop_machine(), which insures that every preempt disabled section | |
823 | * have finished. | |
824 | */ | |
825 | int marker_probe_unregister(const char *channel, const char *name, | |
826 | marker_probe_func *probe, void *probe_private) | |
827 | { | |
828 | struct marker_entry *entry; | |
829 | struct marker_probe_closure *old; | |
830 | int ret = -ENOENT; | |
831 | ||
832 | mutex_lock(&markers_mutex); | |
833 | entry = get_marker(channel, name); | |
834 | if (!entry) | |
835 | goto end; | |
836 | if (entry->rcu_pending) | |
837 | rcu_barrier_sched(); | |
838 | old = marker_entry_remove_probe(entry, probe, probe_private); | |
839 | mutex_unlock(&markers_mutex); | |
840 | ||
841 | marker_update_probes(); | |
842 | ||
843 | mutex_lock(&markers_mutex); | |
844 | entry = get_marker(channel, name); | |
845 | if (!entry) | |
846 | goto end; | |
847 | if (entry->rcu_pending) | |
848 | rcu_barrier_sched(); | |
849 | entry->oldptr = old; | |
850 | entry->rcu_pending = 1; | |
851 | /* write rcu_pending before calling the RCU callback */ | |
852 | smp_wmb(); | |
853 | call_rcu_sched(&entry->rcu, free_old_closure); | |
854 | remove_marker(channel, name); /* Ignore busy error message */ | |
855 | ret = 0; | |
856 | end: | |
857 | mutex_unlock(&markers_mutex); | |
858 | return ret; | |
859 | } | |
860 | EXPORT_SYMBOL_GPL(marker_probe_unregister); | |
861 | ||
862 | static struct marker_entry * | |
863 | get_marker_from_private_data(marker_probe_func *probe, void *probe_private) | |
864 | { | |
865 | struct marker_entry *entry; | |
866 | unsigned int i; | |
867 | struct hlist_head *head; | |
868 | struct hlist_node *node; | |
869 | ||
870 | for (i = 0; i < MARKER_TABLE_SIZE; i++) { | |
871 | head = &marker_table[i]; | |
872 | hlist_for_each_entry(entry, node, head, hlist) { | |
873 | if (!entry->ptype) { | |
874 | if (entry->single.func == probe | |
875 | && entry->single.probe_private | |
876 | == probe_private) | |
877 | return entry; | |
878 | } else { | |
879 | struct marker_probe_closure *closure; | |
880 | closure = entry->multi; | |
881 | for (i = 0; closure[i].func; i++) { | |
882 | if (closure[i].func == probe && | |
883 | closure[i].probe_private | |
884 | == probe_private) | |
885 | return entry; | |
886 | } | |
887 | } | |
888 | } | |
889 | } | |
890 | return NULL; | |
891 | } | |
892 | ||
893 | /** | |
894 | * marker_probe_unregister_private_data - Disconnect a probe from a marker | |
895 | * @probe: probe function | |
896 | * @probe_private: probe private data | |
897 | * | |
898 | * Unregister a probe by providing the registered private data. | |
899 | * Only removes the first marker found in hash table. | |
900 | * Return 0 on success or error value. | |
901 | * We do not need to call a synchronize_sched to make sure the probes have | |
902 | * finished running before doing a module unload, because the module unload | |
903 | * itself uses stop_machine(), which insures that every preempt disabled section | |
904 | * have finished. | |
905 | */ | |
906 | int marker_probe_unregister_private_data(marker_probe_func *probe, | |
907 | void *probe_private) | |
908 | { | |
909 | struct marker_entry *entry; | |
910 | int ret = 0; | |
911 | struct marker_probe_closure *old; | |
912 | const char *channel = NULL, *name = NULL; | |
913 | ||
914 | mutex_lock(&markers_mutex); | |
915 | entry = get_marker_from_private_data(probe, probe_private); | |
916 | if (!entry) { | |
917 | ret = -ENOENT; | |
918 | goto end; | |
919 | } | |
920 | if (entry->rcu_pending) | |
921 | rcu_barrier_sched(); | |
922 | old = marker_entry_remove_probe(entry, NULL, probe_private); | |
923 | channel = kstrdup(entry->channel, GFP_KERNEL); | |
924 | name = kstrdup(entry->name, GFP_KERNEL); | |
925 | mutex_unlock(&markers_mutex); | |
926 | ||
927 | marker_update_probes(); | |
928 | ||
929 | mutex_lock(&markers_mutex); | |
930 | entry = get_marker(channel, name); | |
931 | if (!entry) | |
932 | goto end; | |
933 | if (entry->rcu_pending) | |
934 | rcu_barrier_sched(); | |
935 | entry->oldptr = old; | |
936 | entry->rcu_pending = 1; | |
937 | /* write rcu_pending before calling the RCU callback */ | |
938 | smp_wmb(); | |
939 | call_rcu_sched(&entry->rcu, free_old_closure); | |
940 | /* Ignore busy error message */ | |
941 | remove_marker(channel, name); | |
942 | end: | |
943 | mutex_unlock(&markers_mutex); | |
944 | kfree(channel); | |
945 | kfree(name); | |
946 | return ret; | |
947 | } | |
948 | EXPORT_SYMBOL_GPL(marker_probe_unregister_private_data); | |
949 | ||
950 | /** | |
951 | * marker_get_private_data - Get a marker's probe private data | |
952 | * @channel: marker channel | |
953 | * @name: marker name | |
954 | * @probe: probe to match | |
955 | * @num: get the nth matching probe's private data | |
956 | * | |
957 | * Returns the nth private data pointer (starting from 0) matching, or an | |
958 | * ERR_PTR. | |
959 | * Returns the private data pointer, or an ERR_PTR. | |
960 | * The private data pointer should _only_ be dereferenced if the caller is the | |
961 | * owner of the data, or its content could vanish. This is mostly used to | |
962 | * confirm that a caller is the owner of a registered probe. | |
963 | */ | |
964 | void *marker_get_private_data(const char *channel, const char *name, | |
965 | marker_probe_func *probe, int num) | |
966 | { | |
967 | struct hlist_head *head; | |
968 | struct hlist_node *node; | |
969 | struct marker_entry *e; | |
970 | size_t channel_len = strlen(channel) + 1; | |
971 | size_t name_len = strlen(name) + 1; | |
972 | int i; | |
973 | u32 hash; | |
974 | ||
975 | hash = jhash(channel, channel_len-1, 0) ^ jhash(name, name_len-1, 0); | |
976 | head = &marker_table[hash & ((1 << MARKER_HASH_BITS)-1)]; | |
977 | hlist_for_each_entry(e, node, head, hlist) { | |
978 | if (!strcmp(channel, e->channel) && !strcmp(name, e->name)) { | |
979 | if (!e->ptype) { | |
980 | if (num == 0 && e->single.func == probe) | |
981 | return e->single.probe_private; | |
982 | } else { | |
983 | struct marker_probe_closure *closure; | |
984 | int match = 0; | |
985 | closure = e->multi; | |
986 | for (i = 0; closure[i].func; i++) { | |
987 | if (closure[i].func != probe) | |
988 | continue; | |
989 | if (match++ == num) | |
990 | return closure[i].probe_private; | |
991 | } | |
992 | } | |
993 | break; | |
994 | } | |
995 | } | |
996 | return ERR_PTR(-ENOENT); | |
997 | } | |
998 | EXPORT_SYMBOL_GPL(marker_get_private_data); | |
999 | ||
1000 | /** | |
1001 | * markers_compact_event_ids - Compact markers event IDs and reassign channels | |
1002 | * | |
1003 | * Called when no channel users are active by the channel infrastructure. | |
1004 | * Called with lock_markers() and channel mutex held. | |
1005 | */ | |
1006 | void markers_compact_event_ids(void) | |
1007 | { | |
1008 | struct marker_entry *entry; | |
1009 | unsigned int i; | |
1010 | struct hlist_head *head; | |
1011 | struct hlist_node *node; | |
1012 | int ret; | |
1013 | ||
1014 | for (i = 0; i < MARKER_TABLE_SIZE; i++) { | |
1015 | head = &marker_table[i]; | |
1016 | hlist_for_each_entry(entry, node, head, hlist) { | |
1017 | ret = ltt_channels_get_index_from_name(entry->channel); | |
1018 | WARN_ON(ret < 0); | |
1019 | entry->channel_id = ret; | |
1020 | ret = _ltt_channels_get_event_id(entry->channel, | |
1021 | entry->name); | |
1022 | WARN_ON(ret < 0); | |
1023 | entry->event_id = ret; | |
1024 | } | |
1025 | } | |
1026 | } | |
1027 | ||
1028 | #ifdef CONFIG_MODULES | |
1029 | ||
1030 | /** | |
1031 | * marker_get_iter_range - Get a next marker iterator given a range. | |
1032 | * @marker: current markers (in), next marker (out) | |
1033 | * @begin: beginning of the range | |
1034 | * @end: end of the range | |
1035 | * | |
1036 | * Returns whether a next marker has been found (1) or not (0). | |
1037 | * Will return the first marker in the range if the input marker is NULL. | |
1038 | */ | |
1039 | int marker_get_iter_range(struct marker **marker, struct marker *begin, | |
1040 | struct marker *end) | |
1041 | { | |
1042 | if (!*marker && begin != end) { | |
1043 | *marker = begin; | |
1044 | return 1; | |
1045 | } | |
1046 | if (*marker >= begin && *marker < end) | |
1047 | return 1; | |
1048 | return 0; | |
1049 | } | |
1050 | EXPORT_SYMBOL_GPL(marker_get_iter_range); | |
1051 | ||
1052 | static void marker_get_iter(struct marker_iter *iter) | |
1053 | { | |
1054 | int found = 0; | |
1055 | ||
1056 | /* Core kernel markers */ | |
1057 | if (!iter->module) { | |
1058 | found = marker_get_iter_range(&iter->marker, | |
1059 | __start___markers, __stop___markers); | |
1060 | if (found) | |
1061 | goto end; | |
1062 | } | |
1063 | /* Markers in modules. */ | |
1064 | found = module_get_iter_markers(iter); | |
1065 | end: | |
1066 | if (!found) | |
1067 | marker_iter_reset(iter); | |
1068 | } | |
1069 | ||
1070 | void marker_iter_start(struct marker_iter *iter) | |
1071 | { | |
1072 | marker_get_iter(iter); | |
1073 | } | |
1074 | EXPORT_SYMBOL_GPL(marker_iter_start); | |
1075 | ||
1076 | void marker_iter_next(struct marker_iter *iter) | |
1077 | { | |
1078 | iter->marker++; | |
1079 | /* | |
1080 | * iter->marker may be invalid because we blindly incremented it. | |
1081 | * Make sure it is valid by marshalling on the markers, getting the | |
1082 | * markers from following modules if necessary. | |
1083 | */ | |
1084 | marker_get_iter(iter); | |
1085 | } | |
1086 | EXPORT_SYMBOL_GPL(marker_iter_next); | |
1087 | ||
1088 | void marker_iter_stop(struct marker_iter *iter) | |
1089 | { | |
1090 | } | |
1091 | EXPORT_SYMBOL_GPL(marker_iter_stop); | |
1092 | ||
1093 | void marker_iter_reset(struct marker_iter *iter) | |
1094 | { | |
1095 | iter->module = NULL; | |
1096 | iter->marker = NULL; | |
1097 | } | |
1098 | EXPORT_SYMBOL_GPL(marker_iter_reset); | |
1099 | ||
1100 | #ifdef CONFIG_MARKERS_USERSPACE | |
1101 | /* | |
1102 | * must be called with current->user_markers_mutex held | |
1103 | */ | |
1104 | static void free_user_marker(char __user *state, struct hlist_head *head) | |
1105 | { | |
1106 | struct user_marker *umark; | |
1107 | struct hlist_node *pos, *n; | |
1108 | ||
1109 | hlist_for_each_entry_safe(umark, pos, n, head, hlist) { | |
1110 | if (umark->state == state) { | |
1111 | hlist_del(&umark->hlist); | |
1112 | kfree(umark); | |
1113 | } | |
1114 | } | |
1115 | } | |
1116 | ||
1117 | asmlinkage long sys_marker(char __user *name, char __user *format, | |
1118 | char __user *state, int reg) | |
1119 | { | |
1120 | struct user_marker *umark; | |
1121 | long len; | |
1122 | struct marker_entry *entry; | |
1123 | int ret = 0; | |
1124 | ||
1125 | printk(KERN_DEBUG "Program %s %s marker [%p, %p]\n", | |
1126 | current->comm, reg ? "registers" : "unregisters", | |
1127 | name, state); | |
1128 | if (reg) { | |
1129 | umark = kmalloc(sizeof(struct user_marker), GFP_KERNEL); | |
1130 | umark->name[MAX_USER_MARKER_NAME_LEN - 1] = '\0'; | |
1131 | umark->format[MAX_USER_MARKER_FORMAT_LEN - 1] = '\0'; | |
1132 | umark->state = state; | |
1133 | len = strncpy_from_user(umark->name, name, | |
1134 | MAX_USER_MARKER_NAME_LEN - 1); | |
1135 | if (len < 0) { | |
1136 | ret = -EFAULT; | |
1137 | goto error; | |
1138 | } | |
1139 | len = strncpy_from_user(umark->format, format, | |
1140 | MAX_USER_MARKER_FORMAT_LEN - 1); | |
1141 | if (len < 0) { | |
1142 | ret = -EFAULT; | |
1143 | goto error; | |
1144 | } | |
1145 | printk(KERN_DEBUG "Marker name : %s, format : %s", umark->name, | |
1146 | umark->format); | |
1147 | mutex_lock(&markers_mutex); | |
1148 | entry = get_marker("userspace", umark->name); | |
1149 | if (entry) { | |
1150 | if (entry->format && | |
1151 | strcmp(entry->format, umark->format) != 0) { | |
1152 | printk(" error, wrong format in process %s", | |
1153 | current->comm); | |
1154 | ret = -EPERM; | |
1155 | goto error_unlock; | |
1156 | } | |
1157 | printk(" %s", !!entry->refcount | |
1158 | ? "enabled" : "disabled"); | |
1159 | if (put_user(!!entry->refcount, state)) { | |
1160 | ret = -EFAULT; | |
1161 | goto error_unlock; | |
1162 | } | |
1163 | printk("\n"); | |
1164 | } else { | |
1165 | printk(" disabled\n"); | |
1166 | if (put_user(0, umark->state)) { | |
1167 | printk(KERN_WARNING | |
1168 | "Marker in %s caused a fault\n", | |
1169 | current->comm); | |
1170 | goto error_unlock; | |
1171 | } | |
1172 | } | |
1173 | mutex_lock(¤t->group_leader->user_markers_mutex); | |
1174 | hlist_add_head(&umark->hlist, | |
1175 | ¤t->group_leader->user_markers); | |
1176 | current->group_leader->user_markers_sequence++; | |
1177 | mutex_unlock(¤t->group_leader->user_markers_mutex); | |
1178 | mutex_unlock(&markers_mutex); | |
1179 | } else { | |
1180 | mutex_lock(¤t->group_leader->user_markers_mutex); | |
1181 | free_user_marker(state, | |
1182 | ¤t->group_leader->user_markers); | |
1183 | current->group_leader->user_markers_sequence++; | |
1184 | mutex_unlock(¤t->group_leader->user_markers_mutex); | |
1185 | } | |
1186 | goto end; | |
1187 | error_unlock: | |
1188 | mutex_unlock(&markers_mutex); | |
1189 | error: | |
1190 | kfree(umark); | |
1191 | end: | |
1192 | return ret; | |
1193 | } | |
1194 | ||
1195 | /* | |
1196 | * Types : | |
1197 | * string : 0 | |
1198 | */ | |
1199 | asmlinkage long sys_trace(int type, uint16_t id, | |
1200 | char __user *ubuf) | |
1201 | { | |
1202 | long ret = -EPERM; | |
1203 | char *page; | |
1204 | int len; | |
1205 | ||
1206 | switch (type) { | |
1207 | case 0: /* String */ | |
1208 | ret = -ENOMEM; | |
1209 | page = (char *)__get_free_page(GFP_TEMPORARY); | |
1210 | if (!page) | |
1211 | goto string_out; | |
1212 | len = strncpy_from_user(page, ubuf, PAGE_SIZE); | |
1213 | if (len < 0) { | |
1214 | ret = -EFAULT; | |
1215 | goto string_err; | |
1216 | } | |
1217 | trace_mark(userspace, string, "string %s", page); | |
1218 | string_err: | |
1219 | free_page((unsigned long) page); | |
1220 | string_out: | |
1221 | break; | |
1222 | default: | |
1223 | break; | |
1224 | } | |
1225 | return ret; | |
1226 | } | |
1227 | ||
1228 | static void marker_update_processes(void) | |
1229 | { | |
1230 | struct task_struct *g, *t; | |
1231 | ||
1232 | /* | |
1233 | * markers_mutex is taken to protect the p->user_markers read. | |
1234 | */ | |
1235 | mutex_lock(&markers_mutex); | |
1236 | read_lock(&tasklist_lock); | |
1237 | for_each_process(g) { | |
1238 | WARN_ON(!thread_group_leader(g)); | |
1239 | if (hlist_empty(&g->user_markers)) | |
1240 | continue; | |
1241 | if (strcmp(g->comm, "testprog") == 0) | |
1242 | printk(KERN_DEBUG "set update pending for testprog\n"); | |
1243 | t = g; | |
1244 | do { | |
1245 | /* TODO : implement this thread flag in each arch. */ | |
1246 | set_tsk_thread_flag(t, TIF_MARKER_PENDING); | |
1247 | } while ((t = next_thread(t)) != g); | |
1248 | } | |
1249 | read_unlock(&tasklist_lock); | |
1250 | mutex_unlock(&markers_mutex); | |
1251 | } | |
1252 | ||
1253 | /* | |
1254 | * Update current process. | |
1255 | * Note that we have to wait a whole scheduler period before we are sure that | |
1256 | * every running userspace threads have their markers updated. | |
1257 | * (synchronize_sched() can be used to insure this). | |
1258 | */ | |
1259 | void marker_update_process(void) | |
1260 | { | |
1261 | struct user_marker *umark; | |
1262 | struct hlist_node *pos; | |
1263 | struct marker_entry *entry; | |
1264 | ||
1265 | mutex_lock(&markers_mutex); | |
1266 | mutex_lock(¤t->group_leader->user_markers_mutex); | |
1267 | if (strcmp(current->comm, "testprog") == 0) | |
1268 | printk(KERN_DEBUG "do update pending for testprog\n"); | |
1269 | hlist_for_each_entry(umark, pos, | |
1270 | ¤t->group_leader->user_markers, hlist) { | |
1271 | printk(KERN_DEBUG "Updating marker %s in %s\n", | |
1272 | umark->name, current->comm); | |
1273 | entry = get_marker("userspace", umark->name); | |
1274 | if (entry) { | |
1275 | if (entry->format && | |
1276 | strcmp(entry->format, umark->format) != 0) { | |
1277 | printk(KERN_WARNING | |
1278 | " error, wrong format in process %s\n", | |
1279 | current->comm); | |
1280 | break; | |
1281 | } | |
1282 | if (put_user(!!entry->refcount, umark->state)) { | |
1283 | printk(KERN_WARNING | |
1284 | "Marker in %s caused a fault\n", | |
1285 | current->comm); | |
1286 | break; | |
1287 | } | |
1288 | } else { | |
1289 | if (put_user(0, umark->state)) { | |
1290 | printk(KERN_WARNING | |
1291 | "Marker in %s caused a fault\n", | |
1292 | current->comm); | |
1293 | break; | |
1294 | } | |
1295 | } | |
1296 | } | |
1297 | clear_thread_flag(TIF_MARKER_PENDING); | |
1298 | mutex_unlock(¤t->group_leader->user_markers_mutex); | |
1299 | mutex_unlock(&markers_mutex); | |
1300 | } | |
1301 | ||
1302 | /* | |
1303 | * Called at process exit and upon do_execve(). | |
1304 | * We assume that when the leader exits, no more references can be done to the | |
1305 | * leader structure by the other threads. | |
1306 | */ | |
1307 | void exit_user_markers(struct task_struct *p) | |
1308 | { | |
1309 | struct user_marker *umark; | |
1310 | struct hlist_node *pos, *n; | |
1311 | ||
1312 | if (thread_group_leader(p)) { | |
1313 | mutex_lock(&markers_mutex); | |
1314 | mutex_lock(&p->user_markers_mutex); | |
1315 | hlist_for_each_entry_safe(umark, pos, n, &p->user_markers, | |
1316 | hlist) | |
1317 | kfree(umark); | |
1318 | INIT_HLIST_HEAD(&p->user_markers); | |
1319 | p->user_markers_sequence++; | |
1320 | mutex_unlock(&p->user_markers_mutex); | |
1321 | mutex_unlock(&markers_mutex); | |
1322 | } | |
1323 | } | |
1324 | ||
1325 | int is_marker_enabled(const char *channel, const char *name) | |
1326 | { | |
1327 | struct marker_entry *entry; | |
1328 | ||
1329 | mutex_lock(&markers_mutex); | |
1330 | entry = get_marker(channel, name); | |
1331 | mutex_unlock(&markers_mutex); | |
1332 | ||
1333 | return entry && !!entry->refcount; | |
1334 | } | |
1335 | #endif | |
1336 | ||
1337 | int marker_module_notify(struct notifier_block *self, | |
1338 | unsigned long val, void *data) | |
1339 | { | |
1340 | struct module *mod = data; | |
1341 | ||
1342 | switch (val) { | |
1343 | case MODULE_STATE_COMING: | |
1344 | marker_update_probe_range(mod->markers, | |
1345 | mod->markers + mod->num_markers); | |
1346 | break; | |
1347 | case MODULE_STATE_GOING: | |
1348 | marker_update_probe_range(mod->markers, | |
1349 | mod->markers + mod->num_markers); | |
1350 | break; | |
1351 | } | |
1352 | return 0; | |
1353 | } | |
1354 | ||
1355 | struct notifier_block marker_module_nb = { | |
1356 | .notifier_call = marker_module_notify, | |
1357 | .priority = 0, | |
1358 | }; | |
1359 | ||
1360 | static int init_markers(void) | |
1361 | { | |
1362 | return register_module_notifier(&marker_module_nb); | |
1363 | } | |
1364 | __initcall(init_markers); | |
1365 | ||
1366 | #endif /* CONFIG_MODULES */ | |
1367 | ||
1368 | void ltt_dump_marker_state(struct ltt_trace_struct *trace) | |
1369 | { | |
1370 | struct marker_iter iter; | |
1371 | struct ltt_probe_private_data call_data; | |
1372 | const char *channel; | |
1373 | ||
1374 | call_data.trace = trace; | |
1375 | call_data.serializer = NULL; | |
1376 | ||
1377 | marker_iter_reset(&iter); | |
1378 | marker_iter_start(&iter); | |
1379 | for (; iter.marker != NULL; marker_iter_next(&iter)) { | |
1380 | if (!_imv_read(iter.marker->state)) | |
1381 | continue; | |
1382 | channel = ltt_channels_get_name_from_index( | |
1383 | iter.marker->channel_id); | |
1384 | __trace_mark(0, metadata, core_marker_id, | |
1385 | &call_data, | |
1386 | "channel %s name %s event_id %hu " | |
1387 | "int #1u%zu long #1u%zu pointer #1u%zu " | |
1388 | "size_t #1u%zu alignment #1u%u", | |
1389 | channel, | |
1390 | iter.marker->name, | |
1391 | iter.marker->event_id, | |
1392 | sizeof(int), sizeof(long), | |
1393 | sizeof(void *), sizeof(size_t), | |
1394 | ltt_get_alignment()); | |
1395 | if (iter.marker->format) | |
1396 | __trace_mark(0, metadata, | |
1397 | core_marker_format, | |
1398 | &call_data, | |
1399 | "channel %s name %s format %s", | |
1400 | channel, | |
1401 | iter.marker->name, | |
1402 | iter.marker->format); | |
1403 | } | |
1404 | marker_iter_stop(&iter); | |
1405 | } | |
1406 | EXPORT_SYMBOL_GPL(ltt_dump_marker_state); |