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7491e2c4 TSV |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * event probes | |
4 | * | |
5 | * Part of this code was copied from kernel/trace/trace_kprobe.c written by | |
6 | * Masami Hiramatsu <mhiramat@kernel.org> | |
7 | * | |
8 | * Copyright (C) 2021, VMware Inc, Steven Rostedt <rostedt@goodmis.org> | |
9 | * Copyright (C) 2021, VMware Inc, Tzvetomir Stoyanov tz.stoyanov@gmail.com> | |
10 | * | |
11 | */ | |
12 | #include <linux/module.h> | |
13 | #include <linux/mutex.h> | |
14 | #include <linux/ftrace.h> | |
15 | ||
16 | #include "trace_dynevent.h" | |
17 | #include "trace_probe.h" | |
18 | #include "trace_probe_tmpl.h" | |
f1d3cbfa | 19 | #include "trace_probe_kernel.h" |
7491e2c4 TSV |
20 | |
21 | #define EPROBE_EVENT_SYSTEM "eprobes" | |
22 | ||
23 | struct trace_eprobe { | |
24 | /* tracepoint system */ | |
25 | const char *event_system; | |
26 | ||
27 | /* tracepoint event */ | |
28 | const char *event_name; | |
29 | ||
752be5c5 MHG |
30 | /* filter string for the tracepoint */ |
31 | char *filter_str; | |
32 | ||
7491e2c4 TSV |
33 | struct trace_event_call *event; |
34 | ||
35 | struct dyn_event devent; | |
36 | struct trace_probe tp; | |
37 | }; | |
38 | ||
39 | struct eprobe_data { | |
40 | struct trace_event_file *file; | |
41 | struct trace_eprobe *ep; | |
42 | }; | |
43 | ||
f8bbf8b9 CW |
44 | |
45 | #define for_each_trace_eprobe_tp(ep, _tp) \ | |
46 | list_for_each_entry(ep, trace_probe_probe_list(_tp), tp.list) | |
47 | ||
7491e2c4 TSV |
48 | static int __trace_eprobe_create(int argc, const char *argv[]); |
49 | ||
50 | static void trace_event_probe_cleanup(struct trace_eprobe *ep) | |
51 | { | |
52 | if (!ep) | |
53 | return; | |
54 | trace_probe_cleanup(&ep->tp); | |
55 | kfree(ep->event_name); | |
56 | kfree(ep->event_system); | |
57 | if (ep->event) | |
58 | trace_event_put_ref(ep->event); | |
d1776c02 | 59 | kfree(ep->filter_str); |
7491e2c4 TSV |
60 | kfree(ep); |
61 | } | |
62 | ||
63 | static struct trace_eprobe *to_trace_eprobe(struct dyn_event *ev) | |
64 | { | |
65 | return container_of(ev, struct trace_eprobe, devent); | |
66 | } | |
67 | ||
68 | static int eprobe_dyn_event_create(const char *raw_command) | |
69 | { | |
70 | return trace_probe_create(raw_command, __trace_eprobe_create); | |
71 | } | |
72 | ||
73 | static int eprobe_dyn_event_show(struct seq_file *m, struct dyn_event *ev) | |
74 | { | |
75 | struct trace_eprobe *ep = to_trace_eprobe(ev); | |
76 | int i; | |
77 | ||
78 | seq_printf(m, "e:%s/%s", trace_probe_group_name(&ep->tp), | |
79 | trace_probe_name(&ep->tp)); | |
80 | seq_printf(m, " %s.%s", ep->event_system, ep->event_name); | |
81 | ||
82 | for (i = 0; i < ep->tp.nr_args; i++) | |
83 | seq_printf(m, " %s=%s", ep->tp.args[i].name, ep->tp.args[i].comm); | |
84 | seq_putc(m, '\n'); | |
85 | ||
86 | return 0; | |
87 | } | |
88 | ||
89 | static int unregister_trace_eprobe(struct trace_eprobe *ep) | |
90 | { | |
91 | /* If other probes are on the event, just unregister eprobe */ | |
92 | if (trace_probe_has_sibling(&ep->tp)) | |
93 | goto unreg; | |
94 | ||
95 | /* Enabled event can not be unregistered */ | |
96 | if (trace_probe_is_enabled(&ep->tp)) | |
97 | return -EBUSY; | |
98 | ||
99 | /* Will fail if probe is being used by ftrace or perf */ | |
100 | if (trace_probe_unregister_event_call(&ep->tp)) | |
101 | return -EBUSY; | |
102 | ||
103 | unreg: | |
104 | dyn_event_remove(&ep->devent); | |
105 | trace_probe_unlink(&ep->tp); | |
106 | ||
107 | return 0; | |
108 | } | |
109 | ||
110 | static int eprobe_dyn_event_release(struct dyn_event *ev) | |
111 | { | |
112 | struct trace_eprobe *ep = to_trace_eprobe(ev); | |
113 | int ret = unregister_trace_eprobe(ep); | |
114 | ||
115 | if (!ret) | |
116 | trace_event_probe_cleanup(ep); | |
117 | return ret; | |
118 | } | |
119 | ||
120 | static bool eprobe_dyn_event_is_busy(struct dyn_event *ev) | |
121 | { | |
122 | struct trace_eprobe *ep = to_trace_eprobe(ev); | |
123 | ||
124 | return trace_probe_is_enabled(&ep->tp); | |
125 | } | |
126 | ||
127 | static bool eprobe_dyn_event_match(const char *system, const char *event, | |
128 | int argc, const char **argv, struct dyn_event *ev) | |
129 | { | |
130 | struct trace_eprobe *ep = to_trace_eprobe(ev); | |
7d5fda1c SRV |
131 | const char *slash; |
132 | ||
133 | /* | |
134 | * We match the following: | |
135 | * event only - match all eprobes with event name | |
136 | * system and event only - match all system/event probes | |
95c104c3 | 137 | * system only - match all system probes |
7d5fda1c SRV |
138 | * |
139 | * The below has the above satisfied with more arguments: | |
140 | * | |
141 | * attached system/event - If the arg has the system and event | |
142 | * the probe is attached to, match | |
143 | * probes with the attachment. | |
144 | * | |
145 | * If any more args are given, then it requires a full match. | |
146 | */ | |
147 | ||
148 | /* | |
149 | * If system exists, but this probe is not part of that system | |
150 | * do not match. | |
151 | */ | |
152 | if (system && strcmp(trace_probe_group_name(&ep->tp), system) != 0) | |
153 | return false; | |
154 | ||
155 | /* Must match the event name */ | |
95c104c3 | 156 | if (event[0] != '\0' && strcmp(trace_probe_name(&ep->tp), event) != 0) |
7d5fda1c SRV |
157 | return false; |
158 | ||
159 | /* No arguments match all */ | |
160 | if (argc < 1) | |
161 | return true; | |
162 | ||
163 | /* First argument is the system/event the probe is attached to */ | |
164 | ||
165 | slash = strchr(argv[0], '/'); | |
166 | if (!slash) | |
167 | slash = strchr(argv[0], '.'); | |
168 | if (!slash) | |
169 | return false; | |
170 | ||
171 | if (strncmp(ep->event_system, argv[0], slash - argv[0])) | |
172 | return false; | |
173 | if (strcmp(ep->event_name, slash + 1)) | |
174 | return false; | |
175 | ||
176 | argc--; | |
177 | argv++; | |
178 | ||
179 | /* If there are no other args, then match */ | |
180 | if (argc < 1) | |
181 | return true; | |
182 | ||
183 | return trace_probe_match_command_args(&ep->tp, argc, argv); | |
7491e2c4 TSV |
184 | } |
185 | ||
186 | static struct dyn_event_operations eprobe_dyn_event_ops = { | |
187 | .create = eprobe_dyn_event_create, | |
188 | .show = eprobe_dyn_event_show, | |
189 | .is_busy = eprobe_dyn_event_is_busy, | |
190 | .free = eprobe_dyn_event_release, | |
191 | .match = eprobe_dyn_event_match, | |
192 | }; | |
193 | ||
194 | static struct trace_eprobe *alloc_event_probe(const char *group, | |
195 | const char *this_event, | |
196 | struct trace_event_call *event, | |
197 | int nargs) | |
198 | { | |
199 | struct trace_eprobe *ep; | |
200 | const char *event_name; | |
201 | const char *sys_name; | |
202 | int ret = -ENOMEM; | |
203 | ||
204 | if (!event) | |
205 | return ERR_PTR(-ENODEV); | |
206 | ||
207 | sys_name = event->class->system; | |
208 | event_name = trace_event_name(event); | |
209 | ||
210 | ep = kzalloc(struct_size(ep, tp.args, nargs), GFP_KERNEL); | |
211 | if (!ep) { | |
5615e088 | 212 | trace_event_put_ref(event); |
7491e2c4 TSV |
213 | goto error; |
214 | } | |
215 | ep->event = event; | |
216 | ep->event_name = kstrdup(event_name, GFP_KERNEL); | |
217 | if (!ep->event_name) | |
218 | goto error; | |
219 | ep->event_system = kstrdup(sys_name, GFP_KERNEL); | |
220 | if (!ep->event_system) | |
221 | goto error; | |
222 | ||
035ba760 | 223 | ret = trace_probe_init(&ep->tp, this_event, group, false, nargs); |
7491e2c4 TSV |
224 | if (ret < 0) |
225 | goto error; | |
226 | ||
227 | dyn_event_init(&ep->devent, &eprobe_dyn_event_ops); | |
228 | return ep; | |
229 | error: | |
230 | trace_event_probe_cleanup(ep); | |
231 | return ERR_PTR(ret); | |
232 | } | |
233 | ||
7491e2c4 TSV |
234 | static int eprobe_event_define_fields(struct trace_event_call *event_call) |
235 | { | |
7491e2c4 TSV |
236 | struct eprobe_trace_entry_head field; |
237 | struct trace_probe *tp; | |
238 | ||
239 | tp = trace_probe_primary_from_call(event_call); | |
240 | if (WARN_ON_ONCE(!tp)) | |
241 | return -ENOENT; | |
242 | ||
7491e2c4 TSV |
243 | return traceprobe_define_arg_fields(event_call, sizeof(field), tp); |
244 | } | |
245 | ||
246 | static struct trace_event_fields eprobe_fields_array[] = { | |
247 | { .type = TRACE_FUNCTION_TYPE, | |
248 | .define_fields = eprobe_event_define_fields }, | |
249 | {} | |
250 | }; | |
251 | ||
252 | /* Event entry printers */ | |
253 | static enum print_line_t | |
254 | print_eprobe_event(struct trace_iterator *iter, int flags, | |
255 | struct trace_event *event) | |
256 | { | |
257 | struct eprobe_trace_entry_head *field; | |
258 | struct trace_event_call *pevent; | |
259 | struct trace_event *probed_event; | |
260 | struct trace_seq *s = &iter->seq; | |
b61edd57 | 261 | struct trace_eprobe *ep; |
7491e2c4 | 262 | struct trace_probe *tp; |
b61edd57 | 263 | unsigned int type; |
7491e2c4 TSV |
264 | |
265 | field = (struct eprobe_trace_entry_head *)iter->ent; | |
266 | tp = trace_probe_primary_from_call( | |
267 | container_of(event, struct trace_event_call, event)); | |
268 | if (WARN_ON_ONCE(!tp)) | |
269 | goto out; | |
270 | ||
b61edd57 SRG |
271 | ep = container_of(tp, struct trace_eprobe, tp); |
272 | type = ep->event->event.type; | |
273 | ||
7491e2c4 TSV |
274 | trace_seq_printf(s, "%s: (", trace_probe_name(tp)); |
275 | ||
b61edd57 | 276 | probed_event = ftrace_find_event(type); |
7491e2c4 TSV |
277 | if (probed_event) { |
278 | pevent = container_of(probed_event, struct trace_event_call, event); | |
279 | trace_seq_printf(s, "%s.%s", pevent->class->system, | |
280 | trace_event_name(pevent)); | |
281 | } else { | |
b61edd57 | 282 | trace_seq_printf(s, "%u", type); |
7491e2c4 TSV |
283 | } |
284 | ||
285 | trace_seq_putc(s, ')'); | |
286 | ||
196b6389 | 287 | if (trace_probe_print_args(s, tp->args, tp->nr_args, |
7491e2c4 TSV |
288 | (u8 *)&field[1], field) < 0) |
289 | goto out; | |
290 | ||
291 | trace_seq_putc(s, '\n'); | |
292 | out: | |
293 | return trace_handle_return(s); | |
294 | } | |
295 | ||
672a2bf8 SC |
296 | static nokprobe_inline unsigned long |
297 | get_event_field(struct fetch_insn *code, void *rec) | |
7491e2c4 TSV |
298 | { |
299 | struct ftrace_event_field *field = code->data; | |
300 | unsigned long val; | |
301 | void *addr; | |
302 | ||
303 | addr = rec + field->offset; | |
304 | ||
f04dec93 SRG |
305 | if (is_string_field(field)) { |
306 | switch (field->filter_type) { | |
307 | case FILTER_DYN_STRING: | |
308 | val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff)); | |
309 | break; | |
310 | case FILTER_RDYN_STRING: | |
311 | val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff)); | |
312 | break; | |
313 | case FILTER_STATIC_STRING: | |
314 | val = (unsigned long)addr; | |
315 | break; | |
316 | case FILTER_PTR_STRING: | |
317 | val = (unsigned long)(*(char *)addr); | |
318 | break; | |
319 | default: | |
320 | WARN_ON_ONCE(1); | |
321 | return 0; | |
322 | } | |
323 | return val; | |
324 | } | |
325 | ||
7491e2c4 TSV |
326 | switch (field->size) { |
327 | case 1: | |
328 | if (field->is_signed) | |
329 | val = *(char *)addr; | |
330 | else | |
331 | val = *(unsigned char *)addr; | |
332 | break; | |
333 | case 2: | |
334 | if (field->is_signed) | |
335 | val = *(short *)addr; | |
336 | else | |
337 | val = *(unsigned short *)addr; | |
338 | break; | |
339 | case 4: | |
340 | if (field->is_signed) | |
341 | val = *(int *)addr; | |
342 | else | |
343 | val = *(unsigned int *)addr; | |
344 | break; | |
345 | default: | |
346 | if (field->is_signed) | |
347 | val = *(long *)addr; | |
348 | else | |
349 | val = *(unsigned long *)addr; | |
350 | break; | |
351 | } | |
352 | return val; | |
353 | } | |
354 | ||
355 | static int get_eprobe_size(struct trace_probe *tp, void *rec) | |
356 | { | |
6a832ec3 | 357 | struct fetch_insn *code; |
7491e2c4 TSV |
358 | struct probe_arg *arg; |
359 | int i, len, ret = 0; | |
360 | ||
361 | for (i = 0; i < tp->nr_args; i++) { | |
362 | arg = tp->args + i; | |
6a832ec3 | 363 | if (arg->dynamic) { |
7491e2c4 TSV |
364 | unsigned long val; |
365 | ||
6a832ec3 SRG |
366 | code = arg->code; |
367 | retry: | |
368 | switch (code->op) { | |
369 | case FETCH_OP_TP_ARG: | |
370 | val = get_event_field(code, rec); | |
371 | break; | |
6a832ec3 SRG |
372 | case FETCH_NOP_SYMBOL: /* Ignore a place holder */ |
373 | code++; | |
374 | goto retry; | |
375 | default: | |
bd78acc8 SC |
376 | if (process_common_fetch_insn(code, &val) < 0) |
377 | continue; | |
6a832ec3 SRG |
378 | } |
379 | code++; | |
380 | len = process_fetch_insn_bottom(code, val, NULL, NULL); | |
7491e2c4 TSV |
381 | if (len > 0) |
382 | ret += len; | |
383 | } | |
384 | } | |
385 | ||
386 | return ret; | |
387 | } | |
388 | ||
389 | /* Kprobe specific fetch functions */ | |
390 | ||
391 | /* Note that we don't verify it, since the code does not come from user space */ | |
392 | static int | |
25f00e40 MHG |
393 | process_fetch_insn(struct fetch_insn *code, void *rec, void *edata, |
394 | void *dest, void *base) | |
7491e2c4 TSV |
395 | { |
396 | unsigned long val; | |
bd78acc8 | 397 | int ret; |
7491e2c4 | 398 | |
6a832ec3 SRG |
399 | retry: |
400 | switch (code->op) { | |
401 | case FETCH_OP_TP_ARG: | |
402 | val = get_event_field(code, rec); | |
403 | break; | |
6a832ec3 SRG |
404 | case FETCH_NOP_SYMBOL: /* Ignore a place holder */ |
405 | code++; | |
406 | goto retry; | |
407 | default: | |
bd78acc8 SC |
408 | ret = process_common_fetch_insn(code, &val); |
409 | if (ret < 0) | |
410 | return ret; | |
6a832ec3 SRG |
411 | } |
412 | code++; | |
413 | return process_fetch_insn_bottom(code, val, dest, base); | |
7491e2c4 TSV |
414 | } |
415 | NOKPROBE_SYMBOL(process_fetch_insn) | |
416 | ||
7491e2c4 TSV |
417 | /* eprobe handler */ |
418 | static inline void | |
419 | __eprobe_trace_func(struct eprobe_data *edata, void *rec) | |
420 | { | |
421 | struct eprobe_trace_entry_head *entry; | |
422 | struct trace_event_call *call = trace_probe_event_call(&edata->ep->tp); | |
423 | struct trace_event_buffer fbuffer; | |
424 | int dsize; | |
425 | ||
426 | if (WARN_ON_ONCE(call != edata->file->event_call)) | |
427 | return; | |
428 | ||
429 | if (trace_trigger_soft_disabled(edata->file)) | |
430 | return; | |
431 | ||
7491e2c4 | 432 | dsize = get_eprobe_size(&edata->ep->tp, rec); |
3e8b1a29 SRV |
433 | |
434 | entry = trace_event_buffer_reserve(&fbuffer, edata->file, | |
435 | sizeof(*entry) + edata->ep->tp.size + dsize); | |
436 | ||
437 | if (!entry) | |
7491e2c4 TSV |
438 | return; |
439 | ||
440 | entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); | |
25f00e40 | 441 | store_trace_args(&entry[1], &edata->ep->tp, rec, NULL, sizeof(*entry), dsize); |
7491e2c4 TSV |
442 | |
443 | trace_event_buffer_commit(&fbuffer); | |
444 | } | |
445 | ||
446 | /* | |
447 | * The event probe implementation uses event triggers to get access to | |
448 | * the event it is attached to, but is not an actual trigger. The below | |
449 | * functions are just stubs to fulfill what is needed to use the trigger | |
450 | * infrastructure. | |
451 | */ | |
47670541 | 452 | static int eprobe_trigger_init(struct event_trigger_data *data) |
7491e2c4 TSV |
453 | { |
454 | return 0; | |
455 | } | |
456 | ||
47670541 | 457 | static void eprobe_trigger_free(struct event_trigger_data *data) |
7491e2c4 TSV |
458 | { |
459 | ||
460 | } | |
461 | ||
462 | static int eprobe_trigger_print(struct seq_file *m, | |
7491e2c4 TSV |
463 | struct event_trigger_data *data) |
464 | { | |
465 | /* Do not print eprobe event triggers */ | |
466 | return 0; | |
467 | } | |
468 | ||
469 | static void eprobe_trigger_func(struct event_trigger_data *data, | |
470 | struct trace_buffer *buffer, void *rec, | |
471 | struct ring_buffer_event *rbe) | |
472 | { | |
473 | struct eprobe_data *edata = data->private_data; | |
474 | ||
94eedf3d SRG |
475 | if (unlikely(!rec)) |
476 | return; | |
477 | ||
7491e2c4 TSV |
478 | __eprobe_trace_func(edata, rec); |
479 | } | |
480 | ||
481 | static struct event_trigger_ops eprobe_trigger_ops = { | |
fb339e53 | 482 | .trigger = eprobe_trigger_func, |
7491e2c4 TSV |
483 | .print = eprobe_trigger_print, |
484 | .init = eprobe_trigger_init, | |
485 | .free = eprobe_trigger_free, | |
486 | }; | |
487 | ||
9ec5a7d1 TZ |
488 | static int eprobe_trigger_cmd_parse(struct event_command *cmd_ops, |
489 | struct trace_event_file *file, | |
e1f187d0 TZ |
490 | char *glob, char *cmd, |
491 | char *param_and_filter) | |
7491e2c4 TSV |
492 | { |
493 | return -1; | |
494 | } | |
495 | ||
2378a2d6 TZ |
496 | static int eprobe_trigger_reg_func(char *glob, |
497 | struct event_trigger_data *data, | |
498 | struct trace_event_file *file) | |
7491e2c4 TSV |
499 | { |
500 | return -1; | |
501 | } | |
502 | ||
2378a2d6 TZ |
503 | static void eprobe_trigger_unreg_func(char *glob, |
504 | struct event_trigger_data *data, | |
505 | struct trace_event_file *file) | |
7491e2c4 TSV |
506 | { |
507 | ||
508 | } | |
509 | ||
510 | static struct event_trigger_ops *eprobe_trigger_get_ops(char *cmd, | |
511 | char *param) | |
512 | { | |
513 | return &eprobe_trigger_ops; | |
514 | } | |
515 | ||
516 | static struct event_command event_trigger_cmd = { | |
517 | .name = "eprobe", | |
518 | .trigger_type = ETT_EVENT_EPROBE, | |
519 | .flags = EVENT_CMD_FL_NEEDS_REC, | |
9ec5a7d1 | 520 | .parse = eprobe_trigger_cmd_parse, |
7491e2c4 TSV |
521 | .reg = eprobe_trigger_reg_func, |
522 | .unreg = eprobe_trigger_unreg_func, | |
523 | .unreg_all = NULL, | |
524 | .get_trigger_ops = eprobe_trigger_get_ops, | |
525 | .set_filter = NULL, | |
526 | }; | |
527 | ||
528 | static struct event_trigger_data * | |
529 | new_eprobe_trigger(struct trace_eprobe *ep, struct trace_event_file *file) | |
530 | { | |
531 | struct event_trigger_data *trigger; | |
752be5c5 | 532 | struct event_filter *filter = NULL; |
7491e2c4 | 533 | struct eprobe_data *edata; |
752be5c5 | 534 | int ret; |
7491e2c4 TSV |
535 | |
536 | edata = kzalloc(sizeof(*edata), GFP_KERNEL); | |
537 | trigger = kzalloc(sizeof(*trigger), GFP_KERNEL); | |
538 | if (!trigger || !edata) { | |
752be5c5 MHG |
539 | ret = -ENOMEM; |
540 | goto error; | |
7491e2c4 TSV |
541 | } |
542 | ||
543 | trigger->flags = EVENT_TRIGGER_FL_PROBE; | |
544 | trigger->count = -1; | |
545 | trigger->ops = &eprobe_trigger_ops; | |
546 | ||
547 | /* | |
548 | * EVENT PROBE triggers are not registered as commands with | |
549 | * register_event_command(), as they are not controlled by the user | |
550 | * from the trigger file | |
551 | */ | |
552 | trigger->cmd_ops = &event_trigger_cmd; | |
553 | ||
554 | INIT_LIST_HEAD(&trigger->list); | |
752be5c5 MHG |
555 | |
556 | if (ep->filter_str) { | |
40adaf51 | 557 | ret = create_event_filter(file->tr, ep->event, |
752be5c5 MHG |
558 | ep->filter_str, false, &filter); |
559 | if (ret) | |
560 | goto error; | |
561 | } | |
562 | RCU_INIT_POINTER(trigger->filter, filter); | |
7491e2c4 TSV |
563 | |
564 | edata->file = file; | |
565 | edata->ep = ep; | |
566 | trigger->private_data = edata; | |
567 | ||
568 | return trigger; | |
752be5c5 MHG |
569 | error: |
570 | free_event_filter(filter); | |
571 | kfree(edata); | |
572 | kfree(trigger); | |
573 | return ERR_PTR(ret); | |
7491e2c4 TSV |
574 | } |
575 | ||
576 | static int enable_eprobe(struct trace_eprobe *ep, | |
577 | struct trace_event_file *eprobe_file) | |
578 | { | |
579 | struct event_trigger_data *trigger; | |
580 | struct trace_event_file *file; | |
581 | struct trace_array *tr = eprobe_file->tr; | |
582 | ||
583 | file = find_event_file(tr, ep->event_system, ep->event_name); | |
584 | if (!file) | |
585 | return -ENOENT; | |
586 | trigger = new_eprobe_trigger(ep, eprobe_file); | |
587 | if (IS_ERR(trigger)) | |
588 | return PTR_ERR(trigger); | |
589 | ||
590 | list_add_tail_rcu(&trigger->list, &file->triggers); | |
591 | ||
592 | trace_event_trigger_enable_disable(file, 1); | |
593 | update_cond_flag(file); | |
594 | ||
595 | return 0; | |
596 | } | |
597 | ||
598 | static struct trace_event_functions eprobe_funcs = { | |
599 | .trace = print_eprobe_event | |
600 | }; | |
601 | ||
602 | static int disable_eprobe(struct trace_eprobe *ep, | |
603 | struct trace_array *tr) | |
604 | { | |
ba27d855 | 605 | struct event_trigger_data *trigger = NULL, *iter; |
7491e2c4 | 606 | struct trace_event_file *file; |
752be5c5 | 607 | struct event_filter *filter; |
7491e2c4 TSV |
608 | struct eprobe_data *edata; |
609 | ||
610 | file = find_event_file(tr, ep->event_system, ep->event_name); | |
611 | if (!file) | |
612 | return -ENOENT; | |
613 | ||
ba27d855 JK |
614 | list_for_each_entry(iter, &file->triggers, list) { |
615 | if (!(iter->flags & EVENT_TRIGGER_FL_PROBE)) | |
7491e2c4 | 616 | continue; |
ba27d855 JK |
617 | edata = iter->private_data; |
618 | if (edata->ep == ep) { | |
619 | trigger = iter; | |
7491e2c4 | 620 | break; |
ba27d855 | 621 | } |
7491e2c4 | 622 | } |
ba27d855 | 623 | if (!trigger) |
7491e2c4 TSV |
624 | return -ENODEV; |
625 | ||
626 | list_del_rcu(&trigger->list); | |
627 | ||
628 | trace_event_trigger_enable_disable(file, 0); | |
629 | update_cond_flag(file); | |
6675880f VS |
630 | |
631 | /* Make sure nothing is using the edata or trigger */ | |
632 | tracepoint_synchronize_unregister(); | |
633 | ||
752be5c5 MHG |
634 | filter = rcu_access_pointer(trigger->filter); |
635 | ||
636 | if (filter) | |
637 | free_event_filter(filter); | |
6675880f VS |
638 | kfree(edata); |
639 | kfree(trigger); | |
640 | ||
7491e2c4 TSV |
641 | return 0; |
642 | } | |
643 | ||
644 | static int enable_trace_eprobe(struct trace_event_call *call, | |
645 | struct trace_event_file *file) | |
646 | { | |
f8bbf8b9 | 647 | struct trace_probe *tp; |
7491e2c4 TSV |
648 | struct trace_eprobe *ep; |
649 | bool enabled; | |
650 | int ret = 0; | |
cf0a624d | 651 | int cnt = 0; |
7491e2c4 TSV |
652 | |
653 | tp = trace_probe_primary_from_call(call); | |
654 | if (WARN_ON_ONCE(!tp)) | |
655 | return -ENODEV; | |
656 | enabled = trace_probe_is_enabled(tp); | |
657 | ||
658 | /* This also changes "enabled" state */ | |
659 | if (file) { | |
660 | ret = trace_probe_add_file(tp, file); | |
661 | if (ret) | |
662 | return ret; | |
663 | } else | |
664 | trace_probe_set_flag(tp, TP_FLAG_PROFILE); | |
665 | ||
666 | if (enabled) | |
667 | return 0; | |
668 | ||
f8bbf8b9 | 669 | for_each_trace_eprobe_tp(ep, tp) { |
7491e2c4 TSV |
670 | ret = enable_eprobe(ep, file); |
671 | if (ret) | |
672 | break; | |
673 | enabled = true; | |
cf0a624d | 674 | cnt++; |
7491e2c4 TSV |
675 | } |
676 | ||
677 | if (ret) { | |
678 | /* Failed to enable one of them. Roll back all */ | |
cf0a624d TSV |
679 | if (enabled) { |
680 | /* | |
681 | * It's a bug if one failed for something other than memory | |
682 | * not being available but another eprobe succeeded. | |
683 | */ | |
684 | WARN_ON_ONCE(ret != -ENOMEM); | |
685 | ||
f8bbf8b9 | 686 | for_each_trace_eprobe_tp(ep, tp) { |
cf0a624d TSV |
687 | disable_eprobe(ep, file->tr); |
688 | if (!--cnt) | |
689 | break; | |
690 | } | |
691 | } | |
7491e2c4 TSV |
692 | if (file) |
693 | trace_probe_remove_file(tp, file); | |
694 | else | |
695 | trace_probe_clear_flag(tp, TP_FLAG_PROFILE); | |
696 | } | |
697 | ||
698 | return ret; | |
699 | } | |
700 | ||
701 | static int disable_trace_eprobe(struct trace_event_call *call, | |
702 | struct trace_event_file *file) | |
703 | { | |
f8bbf8b9 | 704 | struct trace_probe *tp; |
7491e2c4 TSV |
705 | struct trace_eprobe *ep; |
706 | ||
707 | tp = trace_probe_primary_from_call(call); | |
708 | if (WARN_ON_ONCE(!tp)) | |
709 | return -ENODEV; | |
710 | ||
711 | if (file) { | |
712 | if (!trace_probe_get_file_link(tp, file)) | |
713 | return -ENOENT; | |
714 | if (!trace_probe_has_single_file(tp)) | |
715 | goto out; | |
716 | trace_probe_clear_flag(tp, TP_FLAG_TRACE); | |
717 | } else | |
718 | trace_probe_clear_flag(tp, TP_FLAG_PROFILE); | |
719 | ||
720 | if (!trace_probe_is_enabled(tp)) { | |
f8bbf8b9 | 721 | for_each_trace_eprobe_tp(ep, tp) |
7491e2c4 | 722 | disable_eprobe(ep, file->tr); |
7491e2c4 TSV |
723 | } |
724 | ||
725 | out: | |
726 | if (file) | |
727 | /* | |
728 | * Synchronization is done in below function. For perf event, | |
729 | * file == NULL and perf_trace_event_unreg() calls | |
730 | * tracepoint_synchronize_unregister() to ensure synchronize | |
731 | * event. We don't need to care about it. | |
732 | */ | |
733 | trace_probe_remove_file(tp, file); | |
734 | ||
735 | return 0; | |
736 | } | |
737 | ||
738 | static int eprobe_register(struct trace_event_call *event, | |
739 | enum trace_reg type, void *data) | |
740 | { | |
741 | struct trace_event_file *file = data; | |
742 | ||
743 | switch (type) { | |
744 | case TRACE_REG_REGISTER: | |
745 | return enable_trace_eprobe(event, file); | |
746 | case TRACE_REG_UNREGISTER: | |
747 | return disable_trace_eprobe(event, file); | |
748 | #ifdef CONFIG_PERF_EVENTS | |
749 | case TRACE_REG_PERF_REGISTER: | |
750 | case TRACE_REG_PERF_UNREGISTER: | |
751 | case TRACE_REG_PERF_OPEN: | |
752 | case TRACE_REG_PERF_CLOSE: | |
753 | case TRACE_REG_PERF_ADD: | |
754 | case TRACE_REG_PERF_DEL: | |
755 | return 0; | |
756 | #endif | |
757 | } | |
758 | return 0; | |
759 | } | |
760 | ||
761 | static inline void init_trace_eprobe_call(struct trace_eprobe *ep) | |
762 | { | |
763 | struct trace_event_call *call = trace_probe_event_call(&ep->tp); | |
764 | ||
765 | call->flags = TRACE_EVENT_FL_EPROBE; | |
766 | call->event.funcs = &eprobe_funcs; | |
767 | call->class->fields_array = eprobe_fields_array; | |
768 | call->class->reg = eprobe_register; | |
769 | } | |
770 | ||
771 | static struct trace_event_call * | |
772 | find_and_get_event(const char *system, const char *event_name) | |
773 | { | |
774 | struct trace_event_call *tp_event; | |
775 | const char *name; | |
776 | ||
777 | list_for_each_entry(tp_event, &ftrace_events, list) { | |
778 | /* Skip other probes and ftrace events */ | |
779 | if (tp_event->flags & | |
780 | (TRACE_EVENT_FL_IGNORE_ENABLE | | |
781 | TRACE_EVENT_FL_KPROBE | | |
782 | TRACE_EVENT_FL_UPROBE | | |
783 | TRACE_EVENT_FL_EPROBE)) | |
784 | continue; | |
785 | if (!tp_event->class->system || | |
786 | strcmp(system, tp_event->class->system)) | |
787 | continue; | |
788 | name = trace_event_name(tp_event); | |
789 | if (!name || strcmp(event_name, name)) | |
790 | continue; | |
f843249c | 791 | if (!trace_event_try_get_ref(tp_event)) |
7491e2c4 | 792 | return NULL; |
7491e2c4 | 793 | return tp_event; |
7491e2c4 TSV |
794 | } |
795 | return NULL; | |
796 | } | |
797 | ||
798 | static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[], int i) | |
799 | { | |
1b8b0cd7 MHG |
800 | struct traceprobe_parse_context ctx = { |
801 | .event = ep->event, | |
802 | .flags = TPARG_FL_KERNEL | TPARG_FL_TEVENT, | |
803 | }; | |
7491e2c4 TSV |
804 | int ret; |
805 | ||
1b8b0cd7 | 806 | ret = traceprobe_parse_probe_arg(&ep->tp, i, argv[i], &ctx); |
6a832ec3 SRG |
807 | /* Handle symbols "@" */ |
808 | if (!ret) | |
809 | ret = traceprobe_update_arg(&ep->tp.args[i]); | |
810 | ||
b1d1e904 | 811 | traceprobe_finish_parse(&ctx); |
7491e2c4 TSV |
812 | return ret; |
813 | } | |
814 | ||
752be5c5 MHG |
815 | static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const char *argv[]) |
816 | { | |
342a4a2f | 817 | struct event_filter *dummy = NULL; |
752be5c5 MHG |
818 | int i, ret, len = 0; |
819 | char *p; | |
820 | ||
821 | if (argc == 0) { | |
822 | trace_probe_log_err(0, NO_EP_FILTER); | |
823 | return -EINVAL; | |
824 | } | |
825 | ||
826 | /* Recover the filter string */ | |
827 | for (i = 0; i < argc; i++) | |
828 | len += strlen(argv[i]) + 1; | |
829 | ||
830 | ep->filter_str = kzalloc(len, GFP_KERNEL); | |
831 | if (!ep->filter_str) | |
832 | return -ENOMEM; | |
833 | ||
834 | p = ep->filter_str; | |
835 | for (i = 0; i < argc; i++) { | |
c96abaec QF |
836 | if (i) |
837 | ret = snprintf(p, len, " %s", argv[i]); | |
838 | else | |
839 | ret = snprintf(p, len, "%s", argv[i]); | |
752be5c5 MHG |
840 | p += ret; |
841 | len -= ret; | |
842 | } | |
752be5c5 MHG |
843 | |
844 | /* | |
845 | * Ensure the filter string can be parsed correctly. Note, this | |
846 | * filter string is for the original event, not for the eprobe. | |
847 | */ | |
848 | ret = create_event_filter(top_trace_array(), ep->event, ep->filter_str, | |
849 | true, &dummy); | |
850 | free_event_filter(dummy); | |
851 | if (ret) | |
852 | goto error; | |
853 | ||
854 | return 0; | |
855 | error: | |
856 | kfree(ep->filter_str); | |
857 | ep->filter_str = NULL; | |
858 | return ret; | |
859 | } | |
860 | ||
7491e2c4 TSV |
861 | static int __trace_eprobe_create(int argc, const char *argv[]) |
862 | { | |
863 | /* | |
864 | * Argument syntax: | |
752be5c5 MHG |
865 | * e[:[GRP/][ENAME]] SYSTEM.EVENT [FETCHARGS] [if FILTER] |
866 | * Fetch args (no space): | |
7491e2c4 TSV |
867 | * <name>=$<field>[:TYPE] |
868 | */ | |
869 | const char *event = NULL, *group = EPROBE_EVENT_SYSTEM; | |
870 | const char *sys_event = NULL, *sys_name = NULL; | |
871 | struct trace_event_call *event_call; | |
872 | struct trace_eprobe *ep = NULL; | |
873 | char buf1[MAX_EVENT_NAME_LEN]; | |
874 | char buf2[MAX_EVENT_NAME_LEN]; | |
95c104c3 | 875 | char gbuf[MAX_EVENT_NAME_LEN]; |
752be5c5 MHG |
876 | int ret = 0, filter_idx = 0; |
877 | int i, filter_cnt; | |
7491e2c4 TSV |
878 | |
879 | if (argc < 2 || argv[0][0] != 'e') | |
880 | return -ECANCELED; | |
881 | ||
882 | trace_probe_log_init("event_probe", argc, argv); | |
883 | ||
884 | event = strchr(&argv[0][1], ':'); | |
885 | if (event) { | |
886 | event++; | |
95c104c3 | 887 | ret = traceprobe_parse_event_name(&event, &group, gbuf, |
7491e2c4 TSV |
888 | event - argv[0]); |
889 | if (ret) | |
890 | goto parse_error; | |
7491e2c4 | 891 | } |
7491e2c4 | 892 | |
b774926c | 893 | trace_probe_log_set_index(1); |
7491e2c4 | 894 | sys_event = argv[1]; |
95c104c3 | 895 | ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2, 0); |
d8a64313 | 896 | if (ret || !sys_event || !sys_name) { |
2f63e5d2 | 897 | trace_probe_log_err(0, NO_EVENT_INFO); |
7491e2c4 | 898 | goto parse_error; |
2f63e5d2 | 899 | } |
7491e2c4 | 900 | |
95c104c3 | 901 | if (!event) { |
dc399ade | 902 | strscpy(buf1, sys_event, MAX_EVENT_NAME_LEN); |
95c104c3 LY |
903 | event = buf1; |
904 | } | |
905 | ||
752be5c5 MHG |
906 | for (i = 2; i < argc; i++) { |
907 | if (!strcmp(argv[i], "if")) { | |
908 | filter_idx = i + 1; | |
909 | filter_cnt = argc - filter_idx; | |
910 | argc = i; | |
911 | break; | |
912 | } | |
913 | } | |
914 | ||
7491e2c4 TSV |
915 | mutex_lock(&event_mutex); |
916 | event_call = find_and_get_event(sys_name, sys_event); | |
917 | ep = alloc_event_probe(group, event, event_call, argc - 2); | |
918 | mutex_unlock(&event_mutex); | |
919 | ||
920 | if (IS_ERR(ep)) { | |
921 | ret = PTR_ERR(ep); | |
2f63e5d2 MHG |
922 | if (ret == -ENODEV) |
923 | trace_probe_log_err(0, BAD_ATTACH_EVENT); | |
ddcf906f | 924 | /* This must return -ENOMEM or missing event, else there is a bug */ |
7fa598f9 | 925 | WARN_ON_ONCE(ret != -ENOMEM && ret != -ENODEV); |
5615e088 DC |
926 | ep = NULL; |
927 | goto error; | |
7491e2c4 TSV |
928 | } |
929 | ||
752be5c5 MHG |
930 | if (filter_idx) { |
931 | trace_probe_log_set_index(filter_idx); | |
932 | ret = trace_eprobe_parse_filter(ep, filter_cnt, argv + filter_idx); | |
933 | if (ret) | |
934 | goto parse_error; | |
935 | } else | |
936 | ep->filter_str = NULL; | |
937 | ||
7491e2c4 TSV |
938 | argc -= 2; argv += 2; |
939 | /* parse arguments */ | |
940 | for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { | |
941 | trace_probe_log_set_index(i + 2); | |
942 | ret = trace_eprobe_tp_update_arg(ep, argv, i); | |
943 | if (ret) | |
944 | goto error; | |
945 | } | |
946 | ret = traceprobe_set_print_fmt(&ep->tp, PROBE_PRINT_EVENT); | |
947 | if (ret < 0) | |
948 | goto error; | |
949 | init_trace_eprobe_call(ep); | |
950 | mutex_lock(&event_mutex); | |
951 | ret = trace_probe_register_event_call(&ep->tp); | |
952 | if (ret) { | |
953 | if (ret == -EEXIST) { | |
954 | trace_probe_log_set_index(0); | |
955 | trace_probe_log_err(0, EVENT_EXIST); | |
956 | } | |
957 | mutex_unlock(&event_mutex); | |
958 | goto error; | |
959 | } | |
960 | ret = dyn_event_add(&ep->devent, &ep->tp.event->call); | |
961 | mutex_unlock(&event_mutex); | |
962 | return ret; | |
963 | parse_error: | |
964 | ret = -EINVAL; | |
965 | error: | |
966 | trace_event_probe_cleanup(ep); | |
967 | return ret; | |
968 | } | |
969 | ||
970 | /* | |
971 | * Register dynevent at core_initcall. This allows kernel to setup eprobe | |
972 | * events in postcore_initcall without tracefs. | |
973 | */ | |
974 | static __init int trace_events_eprobe_init_early(void) | |
975 | { | |
976 | int err = 0; | |
977 | ||
978 | err = dyn_event_register(&eprobe_dyn_event_ops); | |
979 | if (err) | |
980 | pr_warn("Could not register eprobe_dyn_event_ops\n"); | |
981 | ||
982 | return err; | |
983 | } | |
984 | core_initcall(trace_events_eprobe_init_early); |