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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 | ||
44 | static int __trace_eprobe_create(int argc, const char *argv[]); | |
45 | ||
46 | static void trace_event_probe_cleanup(struct trace_eprobe *ep) | |
47 | { | |
48 | if (!ep) | |
49 | return; | |
50 | trace_probe_cleanup(&ep->tp); | |
51 | kfree(ep->event_name); | |
52 | kfree(ep->event_system); | |
53 | if (ep->event) | |
54 | trace_event_put_ref(ep->event); | |
d1776c02 | 55 | kfree(ep->filter_str); |
7491e2c4 TSV |
56 | kfree(ep); |
57 | } | |
58 | ||
59 | static struct trace_eprobe *to_trace_eprobe(struct dyn_event *ev) | |
60 | { | |
61 | return container_of(ev, struct trace_eprobe, devent); | |
62 | } | |
63 | ||
64 | static int eprobe_dyn_event_create(const char *raw_command) | |
65 | { | |
66 | return trace_probe_create(raw_command, __trace_eprobe_create); | |
67 | } | |
68 | ||
69 | static int eprobe_dyn_event_show(struct seq_file *m, struct dyn_event *ev) | |
70 | { | |
71 | struct trace_eprobe *ep = to_trace_eprobe(ev); | |
72 | int i; | |
73 | ||
74 | seq_printf(m, "e:%s/%s", trace_probe_group_name(&ep->tp), | |
75 | trace_probe_name(&ep->tp)); | |
76 | seq_printf(m, " %s.%s", ep->event_system, ep->event_name); | |
77 | ||
78 | for (i = 0; i < ep->tp.nr_args; i++) | |
79 | seq_printf(m, " %s=%s", ep->tp.args[i].name, ep->tp.args[i].comm); | |
80 | seq_putc(m, '\n'); | |
81 | ||
82 | return 0; | |
83 | } | |
84 | ||
85 | static int unregister_trace_eprobe(struct trace_eprobe *ep) | |
86 | { | |
87 | /* If other probes are on the event, just unregister eprobe */ | |
88 | if (trace_probe_has_sibling(&ep->tp)) | |
89 | goto unreg; | |
90 | ||
91 | /* Enabled event can not be unregistered */ | |
92 | if (trace_probe_is_enabled(&ep->tp)) | |
93 | return -EBUSY; | |
94 | ||
95 | /* Will fail if probe is being used by ftrace or perf */ | |
96 | if (trace_probe_unregister_event_call(&ep->tp)) | |
97 | return -EBUSY; | |
98 | ||
99 | unreg: | |
100 | dyn_event_remove(&ep->devent); | |
101 | trace_probe_unlink(&ep->tp); | |
102 | ||
103 | return 0; | |
104 | } | |
105 | ||
106 | static int eprobe_dyn_event_release(struct dyn_event *ev) | |
107 | { | |
108 | struct trace_eprobe *ep = to_trace_eprobe(ev); | |
109 | int ret = unregister_trace_eprobe(ep); | |
110 | ||
111 | if (!ret) | |
112 | trace_event_probe_cleanup(ep); | |
113 | return ret; | |
114 | } | |
115 | ||
116 | static bool eprobe_dyn_event_is_busy(struct dyn_event *ev) | |
117 | { | |
118 | struct trace_eprobe *ep = to_trace_eprobe(ev); | |
119 | ||
120 | return trace_probe_is_enabled(&ep->tp); | |
121 | } | |
122 | ||
123 | static bool eprobe_dyn_event_match(const char *system, const char *event, | |
124 | int argc, const char **argv, struct dyn_event *ev) | |
125 | { | |
126 | struct trace_eprobe *ep = to_trace_eprobe(ev); | |
7d5fda1c SRV |
127 | const char *slash; |
128 | ||
129 | /* | |
130 | * We match the following: | |
131 | * event only - match all eprobes with event name | |
132 | * system and event only - match all system/event probes | |
95c104c3 | 133 | * system only - match all system probes |
7d5fda1c SRV |
134 | * |
135 | * The below has the above satisfied with more arguments: | |
136 | * | |
137 | * attached system/event - If the arg has the system and event | |
138 | * the probe is attached to, match | |
139 | * probes with the attachment. | |
140 | * | |
141 | * If any more args are given, then it requires a full match. | |
142 | */ | |
143 | ||
144 | /* | |
145 | * If system exists, but this probe is not part of that system | |
146 | * do not match. | |
147 | */ | |
148 | if (system && strcmp(trace_probe_group_name(&ep->tp), system) != 0) | |
149 | return false; | |
150 | ||
151 | /* Must match the event name */ | |
95c104c3 | 152 | if (event[0] != '\0' && strcmp(trace_probe_name(&ep->tp), event) != 0) |
7d5fda1c SRV |
153 | return false; |
154 | ||
155 | /* No arguments match all */ | |
156 | if (argc < 1) | |
157 | return true; | |
158 | ||
159 | /* First argument is the system/event the probe is attached to */ | |
160 | ||
161 | slash = strchr(argv[0], '/'); | |
162 | if (!slash) | |
163 | slash = strchr(argv[0], '.'); | |
164 | if (!slash) | |
165 | return false; | |
166 | ||
167 | if (strncmp(ep->event_system, argv[0], slash - argv[0])) | |
168 | return false; | |
169 | if (strcmp(ep->event_name, slash + 1)) | |
170 | return false; | |
171 | ||
172 | argc--; | |
173 | argv++; | |
174 | ||
175 | /* If there are no other args, then match */ | |
176 | if (argc < 1) | |
177 | return true; | |
178 | ||
179 | return trace_probe_match_command_args(&ep->tp, argc, argv); | |
7491e2c4 TSV |
180 | } |
181 | ||
182 | static struct dyn_event_operations eprobe_dyn_event_ops = { | |
183 | .create = eprobe_dyn_event_create, | |
184 | .show = eprobe_dyn_event_show, | |
185 | .is_busy = eprobe_dyn_event_is_busy, | |
186 | .free = eprobe_dyn_event_release, | |
187 | .match = eprobe_dyn_event_match, | |
188 | }; | |
189 | ||
190 | static struct trace_eprobe *alloc_event_probe(const char *group, | |
191 | const char *this_event, | |
192 | struct trace_event_call *event, | |
193 | int nargs) | |
194 | { | |
195 | struct trace_eprobe *ep; | |
196 | const char *event_name; | |
197 | const char *sys_name; | |
198 | int ret = -ENOMEM; | |
199 | ||
200 | if (!event) | |
201 | return ERR_PTR(-ENODEV); | |
202 | ||
203 | sys_name = event->class->system; | |
204 | event_name = trace_event_name(event); | |
205 | ||
206 | ep = kzalloc(struct_size(ep, tp.args, nargs), GFP_KERNEL); | |
207 | if (!ep) { | |
5615e088 | 208 | trace_event_put_ref(event); |
7491e2c4 TSV |
209 | goto error; |
210 | } | |
211 | ep->event = event; | |
212 | ep->event_name = kstrdup(event_name, GFP_KERNEL); | |
213 | if (!ep->event_name) | |
214 | goto error; | |
215 | ep->event_system = kstrdup(sys_name, GFP_KERNEL); | |
216 | if (!ep->event_system) | |
217 | goto error; | |
218 | ||
219 | ret = trace_probe_init(&ep->tp, this_event, group, false); | |
220 | if (ret < 0) | |
221 | goto error; | |
222 | ||
223 | dyn_event_init(&ep->devent, &eprobe_dyn_event_ops); | |
224 | return ep; | |
225 | error: | |
226 | trace_event_probe_cleanup(ep); | |
227 | return ERR_PTR(ret); | |
228 | } | |
229 | ||
230 | static int trace_eprobe_tp_arg_update(struct trace_eprobe *ep, int i) | |
231 | { | |
232 | struct probe_arg *parg = &ep->tp.args[i]; | |
233 | struct ftrace_event_field *field; | |
234 | struct list_head *head; | |
6a832ec3 | 235 | int ret = -ENOENT; |
7491e2c4 TSV |
236 | |
237 | head = trace_get_fields(ep->event); | |
238 | list_for_each_entry(field, head, link) { | |
239 | if (!strcmp(parg->code->data, field->name)) { | |
240 | kfree(parg->code->data); | |
241 | parg->code->data = field; | |
242 | return 0; | |
243 | } | |
244 | } | |
6a832ec3 SRG |
245 | |
246 | /* | |
247 | * Argument not found on event. But allow for comm and COMM | |
248 | * to be used to get the current->comm. | |
249 | */ | |
250 | if (strcmp(parg->code->data, "COMM") == 0 || | |
251 | strcmp(parg->code->data, "comm") == 0) { | |
252 | parg->code->op = FETCH_OP_COMM; | |
253 | ret = 0; | |
254 | } | |
255 | ||
7491e2c4 TSV |
256 | kfree(parg->code->data); |
257 | parg->code->data = NULL; | |
6a832ec3 | 258 | return ret; |
7491e2c4 TSV |
259 | } |
260 | ||
261 | static int eprobe_event_define_fields(struct trace_event_call *event_call) | |
262 | { | |
7491e2c4 TSV |
263 | struct eprobe_trace_entry_head field; |
264 | struct trace_probe *tp; | |
265 | ||
266 | tp = trace_probe_primary_from_call(event_call); | |
267 | if (WARN_ON_ONCE(!tp)) | |
268 | return -ENOENT; | |
269 | ||
7491e2c4 TSV |
270 | return traceprobe_define_arg_fields(event_call, sizeof(field), tp); |
271 | } | |
272 | ||
273 | static struct trace_event_fields eprobe_fields_array[] = { | |
274 | { .type = TRACE_FUNCTION_TYPE, | |
275 | .define_fields = eprobe_event_define_fields }, | |
276 | {} | |
277 | }; | |
278 | ||
279 | /* Event entry printers */ | |
280 | static enum print_line_t | |
281 | print_eprobe_event(struct trace_iterator *iter, int flags, | |
282 | struct trace_event *event) | |
283 | { | |
284 | struct eprobe_trace_entry_head *field; | |
285 | struct trace_event_call *pevent; | |
286 | struct trace_event *probed_event; | |
287 | struct trace_seq *s = &iter->seq; | |
b61edd57 | 288 | struct trace_eprobe *ep; |
7491e2c4 | 289 | struct trace_probe *tp; |
b61edd57 | 290 | unsigned int type; |
7491e2c4 TSV |
291 | |
292 | field = (struct eprobe_trace_entry_head *)iter->ent; | |
293 | tp = trace_probe_primary_from_call( | |
294 | container_of(event, struct trace_event_call, event)); | |
295 | if (WARN_ON_ONCE(!tp)) | |
296 | goto out; | |
297 | ||
b61edd57 SRG |
298 | ep = container_of(tp, struct trace_eprobe, tp); |
299 | type = ep->event->event.type; | |
300 | ||
7491e2c4 TSV |
301 | trace_seq_printf(s, "%s: (", trace_probe_name(tp)); |
302 | ||
b61edd57 | 303 | probed_event = ftrace_find_event(type); |
7491e2c4 TSV |
304 | if (probed_event) { |
305 | pevent = container_of(probed_event, struct trace_event_call, event); | |
306 | trace_seq_printf(s, "%s.%s", pevent->class->system, | |
307 | trace_event_name(pevent)); | |
308 | } else { | |
b61edd57 | 309 | trace_seq_printf(s, "%u", type); |
7491e2c4 TSV |
310 | } |
311 | ||
312 | trace_seq_putc(s, ')'); | |
313 | ||
196b6389 | 314 | if (trace_probe_print_args(s, tp->args, tp->nr_args, |
7491e2c4 TSV |
315 | (u8 *)&field[1], field) < 0) |
316 | goto out; | |
317 | ||
318 | trace_seq_putc(s, '\n'); | |
319 | out: | |
320 | return trace_handle_return(s); | |
321 | } | |
322 | ||
672a2bf8 SC |
323 | static nokprobe_inline unsigned long |
324 | get_event_field(struct fetch_insn *code, void *rec) | |
7491e2c4 TSV |
325 | { |
326 | struct ftrace_event_field *field = code->data; | |
327 | unsigned long val; | |
328 | void *addr; | |
329 | ||
330 | addr = rec + field->offset; | |
331 | ||
f04dec93 SRG |
332 | if (is_string_field(field)) { |
333 | switch (field->filter_type) { | |
334 | case FILTER_DYN_STRING: | |
335 | val = (unsigned long)(rec + (*(unsigned int *)addr & 0xffff)); | |
336 | break; | |
337 | case FILTER_RDYN_STRING: | |
338 | val = (unsigned long)(addr + (*(unsigned int *)addr & 0xffff)); | |
339 | break; | |
340 | case FILTER_STATIC_STRING: | |
341 | val = (unsigned long)addr; | |
342 | break; | |
343 | case FILTER_PTR_STRING: | |
344 | val = (unsigned long)(*(char *)addr); | |
345 | break; | |
346 | default: | |
347 | WARN_ON_ONCE(1); | |
348 | return 0; | |
349 | } | |
350 | return val; | |
351 | } | |
352 | ||
7491e2c4 TSV |
353 | switch (field->size) { |
354 | case 1: | |
355 | if (field->is_signed) | |
356 | val = *(char *)addr; | |
357 | else | |
358 | val = *(unsigned char *)addr; | |
359 | break; | |
360 | case 2: | |
361 | if (field->is_signed) | |
362 | val = *(short *)addr; | |
363 | else | |
364 | val = *(unsigned short *)addr; | |
365 | break; | |
366 | case 4: | |
367 | if (field->is_signed) | |
368 | val = *(int *)addr; | |
369 | else | |
370 | val = *(unsigned int *)addr; | |
371 | break; | |
372 | default: | |
373 | if (field->is_signed) | |
374 | val = *(long *)addr; | |
375 | else | |
376 | val = *(unsigned long *)addr; | |
377 | break; | |
378 | } | |
379 | return val; | |
380 | } | |
381 | ||
382 | static int get_eprobe_size(struct trace_probe *tp, void *rec) | |
383 | { | |
6a832ec3 | 384 | struct fetch_insn *code; |
7491e2c4 TSV |
385 | struct probe_arg *arg; |
386 | int i, len, ret = 0; | |
387 | ||
388 | for (i = 0; i < tp->nr_args; i++) { | |
389 | arg = tp->args + i; | |
6a832ec3 | 390 | if (arg->dynamic) { |
7491e2c4 TSV |
391 | unsigned long val; |
392 | ||
6a832ec3 SRG |
393 | code = arg->code; |
394 | retry: | |
395 | switch (code->op) { | |
396 | case FETCH_OP_TP_ARG: | |
397 | val = get_event_field(code, rec); | |
398 | break; | |
6a832ec3 SRG |
399 | case FETCH_NOP_SYMBOL: /* Ignore a place holder */ |
400 | code++; | |
401 | goto retry; | |
402 | default: | |
bd78acc8 SC |
403 | if (process_common_fetch_insn(code, &val) < 0) |
404 | continue; | |
6a832ec3 SRG |
405 | } |
406 | code++; | |
407 | len = process_fetch_insn_bottom(code, val, NULL, NULL); | |
7491e2c4 TSV |
408 | if (len > 0) |
409 | ret += len; | |
410 | } | |
411 | } | |
412 | ||
413 | return ret; | |
414 | } | |
415 | ||
416 | /* Kprobe specific fetch functions */ | |
417 | ||
418 | /* Note that we don't verify it, since the code does not come from user space */ | |
419 | static int | |
420 | process_fetch_insn(struct fetch_insn *code, void *rec, void *dest, | |
421 | void *base) | |
422 | { | |
423 | unsigned long val; | |
bd78acc8 | 424 | int ret; |
7491e2c4 | 425 | |
6a832ec3 SRG |
426 | retry: |
427 | switch (code->op) { | |
428 | case FETCH_OP_TP_ARG: | |
429 | val = get_event_field(code, rec); | |
430 | break; | |
6a832ec3 SRG |
431 | case FETCH_NOP_SYMBOL: /* Ignore a place holder */ |
432 | code++; | |
433 | goto retry; | |
434 | default: | |
bd78acc8 SC |
435 | ret = process_common_fetch_insn(code, &val); |
436 | if (ret < 0) | |
437 | return ret; | |
6a832ec3 SRG |
438 | } |
439 | code++; | |
440 | return process_fetch_insn_bottom(code, val, dest, base); | |
7491e2c4 TSV |
441 | } |
442 | NOKPROBE_SYMBOL(process_fetch_insn) | |
443 | ||
7491e2c4 TSV |
444 | /* eprobe handler */ |
445 | static inline void | |
446 | __eprobe_trace_func(struct eprobe_data *edata, void *rec) | |
447 | { | |
448 | struct eprobe_trace_entry_head *entry; | |
449 | struct trace_event_call *call = trace_probe_event_call(&edata->ep->tp); | |
450 | struct trace_event_buffer fbuffer; | |
451 | int dsize; | |
452 | ||
453 | if (WARN_ON_ONCE(call != edata->file->event_call)) | |
454 | return; | |
455 | ||
456 | if (trace_trigger_soft_disabled(edata->file)) | |
457 | return; | |
458 | ||
7491e2c4 | 459 | dsize = get_eprobe_size(&edata->ep->tp, rec); |
3e8b1a29 SRV |
460 | |
461 | entry = trace_event_buffer_reserve(&fbuffer, edata->file, | |
462 | sizeof(*entry) + edata->ep->tp.size + dsize); | |
463 | ||
464 | if (!entry) | |
7491e2c4 TSV |
465 | return; |
466 | ||
467 | entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); | |
7491e2c4 TSV |
468 | store_trace_args(&entry[1], &edata->ep->tp, rec, sizeof(*entry), dsize); |
469 | ||
470 | trace_event_buffer_commit(&fbuffer); | |
471 | } | |
472 | ||
473 | /* | |
474 | * The event probe implementation uses event triggers to get access to | |
475 | * the event it is attached to, but is not an actual trigger. The below | |
476 | * functions are just stubs to fulfill what is needed to use the trigger | |
477 | * infrastructure. | |
478 | */ | |
47670541 | 479 | static int eprobe_trigger_init(struct event_trigger_data *data) |
7491e2c4 TSV |
480 | { |
481 | return 0; | |
482 | } | |
483 | ||
47670541 | 484 | static void eprobe_trigger_free(struct event_trigger_data *data) |
7491e2c4 TSV |
485 | { |
486 | ||
487 | } | |
488 | ||
489 | static int eprobe_trigger_print(struct seq_file *m, | |
7491e2c4 TSV |
490 | struct event_trigger_data *data) |
491 | { | |
492 | /* Do not print eprobe event triggers */ | |
493 | return 0; | |
494 | } | |
495 | ||
496 | static void eprobe_trigger_func(struct event_trigger_data *data, | |
497 | struct trace_buffer *buffer, void *rec, | |
498 | struct ring_buffer_event *rbe) | |
499 | { | |
500 | struct eprobe_data *edata = data->private_data; | |
501 | ||
94eedf3d SRG |
502 | if (unlikely(!rec)) |
503 | return; | |
504 | ||
7491e2c4 TSV |
505 | __eprobe_trace_func(edata, rec); |
506 | } | |
507 | ||
508 | static struct event_trigger_ops eprobe_trigger_ops = { | |
fb339e53 | 509 | .trigger = eprobe_trigger_func, |
7491e2c4 TSV |
510 | .print = eprobe_trigger_print, |
511 | .init = eprobe_trigger_init, | |
512 | .free = eprobe_trigger_free, | |
513 | }; | |
514 | ||
9ec5a7d1 TZ |
515 | static int eprobe_trigger_cmd_parse(struct event_command *cmd_ops, |
516 | struct trace_event_file *file, | |
e1f187d0 TZ |
517 | char *glob, char *cmd, |
518 | char *param_and_filter) | |
7491e2c4 TSV |
519 | { |
520 | return -1; | |
521 | } | |
522 | ||
2378a2d6 TZ |
523 | static int eprobe_trigger_reg_func(char *glob, |
524 | struct event_trigger_data *data, | |
525 | struct trace_event_file *file) | |
7491e2c4 TSV |
526 | { |
527 | return -1; | |
528 | } | |
529 | ||
2378a2d6 TZ |
530 | static void eprobe_trigger_unreg_func(char *glob, |
531 | struct event_trigger_data *data, | |
532 | struct trace_event_file *file) | |
7491e2c4 TSV |
533 | { |
534 | ||
535 | } | |
536 | ||
537 | static struct event_trigger_ops *eprobe_trigger_get_ops(char *cmd, | |
538 | char *param) | |
539 | { | |
540 | return &eprobe_trigger_ops; | |
541 | } | |
542 | ||
543 | static struct event_command event_trigger_cmd = { | |
544 | .name = "eprobe", | |
545 | .trigger_type = ETT_EVENT_EPROBE, | |
546 | .flags = EVENT_CMD_FL_NEEDS_REC, | |
9ec5a7d1 | 547 | .parse = eprobe_trigger_cmd_parse, |
7491e2c4 TSV |
548 | .reg = eprobe_trigger_reg_func, |
549 | .unreg = eprobe_trigger_unreg_func, | |
550 | .unreg_all = NULL, | |
551 | .get_trigger_ops = eprobe_trigger_get_ops, | |
552 | .set_filter = NULL, | |
553 | }; | |
554 | ||
555 | static struct event_trigger_data * | |
556 | new_eprobe_trigger(struct trace_eprobe *ep, struct trace_event_file *file) | |
557 | { | |
558 | struct event_trigger_data *trigger; | |
752be5c5 | 559 | struct event_filter *filter = NULL; |
7491e2c4 | 560 | struct eprobe_data *edata; |
752be5c5 | 561 | int ret; |
7491e2c4 TSV |
562 | |
563 | edata = kzalloc(sizeof(*edata), GFP_KERNEL); | |
564 | trigger = kzalloc(sizeof(*trigger), GFP_KERNEL); | |
565 | if (!trigger || !edata) { | |
752be5c5 MHG |
566 | ret = -ENOMEM; |
567 | goto error; | |
7491e2c4 TSV |
568 | } |
569 | ||
570 | trigger->flags = EVENT_TRIGGER_FL_PROBE; | |
571 | trigger->count = -1; | |
572 | trigger->ops = &eprobe_trigger_ops; | |
573 | ||
574 | /* | |
575 | * EVENT PROBE triggers are not registered as commands with | |
576 | * register_event_command(), as they are not controlled by the user | |
577 | * from the trigger file | |
578 | */ | |
579 | trigger->cmd_ops = &event_trigger_cmd; | |
580 | ||
581 | INIT_LIST_HEAD(&trigger->list); | |
752be5c5 MHG |
582 | |
583 | if (ep->filter_str) { | |
40adaf51 | 584 | ret = create_event_filter(file->tr, ep->event, |
752be5c5 MHG |
585 | ep->filter_str, false, &filter); |
586 | if (ret) | |
587 | goto error; | |
588 | } | |
589 | RCU_INIT_POINTER(trigger->filter, filter); | |
7491e2c4 TSV |
590 | |
591 | edata->file = file; | |
592 | edata->ep = ep; | |
593 | trigger->private_data = edata; | |
594 | ||
595 | return trigger; | |
752be5c5 MHG |
596 | error: |
597 | free_event_filter(filter); | |
598 | kfree(edata); | |
599 | kfree(trigger); | |
600 | return ERR_PTR(ret); | |
7491e2c4 TSV |
601 | } |
602 | ||
603 | static int enable_eprobe(struct trace_eprobe *ep, | |
604 | struct trace_event_file *eprobe_file) | |
605 | { | |
606 | struct event_trigger_data *trigger; | |
607 | struct trace_event_file *file; | |
608 | struct trace_array *tr = eprobe_file->tr; | |
609 | ||
610 | file = find_event_file(tr, ep->event_system, ep->event_name); | |
611 | if (!file) | |
612 | return -ENOENT; | |
613 | trigger = new_eprobe_trigger(ep, eprobe_file); | |
614 | if (IS_ERR(trigger)) | |
615 | return PTR_ERR(trigger); | |
616 | ||
617 | list_add_tail_rcu(&trigger->list, &file->triggers); | |
618 | ||
619 | trace_event_trigger_enable_disable(file, 1); | |
620 | update_cond_flag(file); | |
621 | ||
622 | return 0; | |
623 | } | |
624 | ||
625 | static struct trace_event_functions eprobe_funcs = { | |
626 | .trace = print_eprobe_event | |
627 | }; | |
628 | ||
629 | static int disable_eprobe(struct trace_eprobe *ep, | |
630 | struct trace_array *tr) | |
631 | { | |
ba27d855 | 632 | struct event_trigger_data *trigger = NULL, *iter; |
7491e2c4 | 633 | struct trace_event_file *file; |
752be5c5 | 634 | struct event_filter *filter; |
7491e2c4 TSV |
635 | struct eprobe_data *edata; |
636 | ||
637 | file = find_event_file(tr, ep->event_system, ep->event_name); | |
638 | if (!file) | |
639 | return -ENOENT; | |
640 | ||
ba27d855 JK |
641 | list_for_each_entry(iter, &file->triggers, list) { |
642 | if (!(iter->flags & EVENT_TRIGGER_FL_PROBE)) | |
7491e2c4 | 643 | continue; |
ba27d855 JK |
644 | edata = iter->private_data; |
645 | if (edata->ep == ep) { | |
646 | trigger = iter; | |
7491e2c4 | 647 | break; |
ba27d855 | 648 | } |
7491e2c4 | 649 | } |
ba27d855 | 650 | if (!trigger) |
7491e2c4 TSV |
651 | return -ENODEV; |
652 | ||
653 | list_del_rcu(&trigger->list); | |
654 | ||
655 | trace_event_trigger_enable_disable(file, 0); | |
656 | update_cond_flag(file); | |
6675880f VS |
657 | |
658 | /* Make sure nothing is using the edata or trigger */ | |
659 | tracepoint_synchronize_unregister(); | |
660 | ||
752be5c5 MHG |
661 | filter = rcu_access_pointer(trigger->filter); |
662 | ||
663 | if (filter) | |
664 | free_event_filter(filter); | |
6675880f VS |
665 | kfree(edata); |
666 | kfree(trigger); | |
667 | ||
7491e2c4 TSV |
668 | return 0; |
669 | } | |
670 | ||
671 | static int enable_trace_eprobe(struct trace_event_call *call, | |
672 | struct trace_event_file *file) | |
673 | { | |
674 | struct trace_probe *pos, *tp; | |
675 | struct trace_eprobe *ep; | |
676 | bool enabled; | |
677 | int ret = 0; | |
678 | ||
679 | tp = trace_probe_primary_from_call(call); | |
680 | if (WARN_ON_ONCE(!tp)) | |
681 | return -ENODEV; | |
682 | enabled = trace_probe_is_enabled(tp); | |
683 | ||
684 | /* This also changes "enabled" state */ | |
685 | if (file) { | |
686 | ret = trace_probe_add_file(tp, file); | |
687 | if (ret) | |
688 | return ret; | |
689 | } else | |
690 | trace_probe_set_flag(tp, TP_FLAG_PROFILE); | |
691 | ||
692 | if (enabled) | |
693 | return 0; | |
694 | ||
695 | list_for_each_entry(pos, trace_probe_probe_list(tp), list) { | |
696 | ep = container_of(pos, struct trace_eprobe, tp); | |
697 | ret = enable_eprobe(ep, file); | |
698 | if (ret) | |
699 | break; | |
700 | enabled = true; | |
701 | } | |
702 | ||
703 | if (ret) { | |
704 | /* Failed to enable one of them. Roll back all */ | |
705 | if (enabled) | |
706 | disable_eprobe(ep, file->tr); | |
707 | if (file) | |
708 | trace_probe_remove_file(tp, file); | |
709 | else | |
710 | trace_probe_clear_flag(tp, TP_FLAG_PROFILE); | |
711 | } | |
712 | ||
713 | return ret; | |
714 | } | |
715 | ||
716 | static int disable_trace_eprobe(struct trace_event_call *call, | |
717 | struct trace_event_file *file) | |
718 | { | |
719 | struct trace_probe *pos, *tp; | |
720 | struct trace_eprobe *ep; | |
721 | ||
722 | tp = trace_probe_primary_from_call(call); | |
723 | if (WARN_ON_ONCE(!tp)) | |
724 | return -ENODEV; | |
725 | ||
726 | if (file) { | |
727 | if (!trace_probe_get_file_link(tp, file)) | |
728 | return -ENOENT; | |
729 | if (!trace_probe_has_single_file(tp)) | |
730 | goto out; | |
731 | trace_probe_clear_flag(tp, TP_FLAG_TRACE); | |
732 | } else | |
733 | trace_probe_clear_flag(tp, TP_FLAG_PROFILE); | |
734 | ||
735 | if (!trace_probe_is_enabled(tp)) { | |
736 | list_for_each_entry(pos, trace_probe_probe_list(tp), list) { | |
737 | ep = container_of(pos, struct trace_eprobe, tp); | |
738 | disable_eprobe(ep, file->tr); | |
739 | } | |
740 | } | |
741 | ||
742 | out: | |
743 | if (file) | |
744 | /* | |
745 | * Synchronization is done in below function. For perf event, | |
746 | * file == NULL and perf_trace_event_unreg() calls | |
747 | * tracepoint_synchronize_unregister() to ensure synchronize | |
748 | * event. We don't need to care about it. | |
749 | */ | |
750 | trace_probe_remove_file(tp, file); | |
751 | ||
752 | return 0; | |
753 | } | |
754 | ||
755 | static int eprobe_register(struct trace_event_call *event, | |
756 | enum trace_reg type, void *data) | |
757 | { | |
758 | struct trace_event_file *file = data; | |
759 | ||
760 | switch (type) { | |
761 | case TRACE_REG_REGISTER: | |
762 | return enable_trace_eprobe(event, file); | |
763 | case TRACE_REG_UNREGISTER: | |
764 | return disable_trace_eprobe(event, file); | |
765 | #ifdef CONFIG_PERF_EVENTS | |
766 | case TRACE_REG_PERF_REGISTER: | |
767 | case TRACE_REG_PERF_UNREGISTER: | |
768 | case TRACE_REG_PERF_OPEN: | |
769 | case TRACE_REG_PERF_CLOSE: | |
770 | case TRACE_REG_PERF_ADD: | |
771 | case TRACE_REG_PERF_DEL: | |
772 | return 0; | |
773 | #endif | |
774 | } | |
775 | return 0; | |
776 | } | |
777 | ||
778 | static inline void init_trace_eprobe_call(struct trace_eprobe *ep) | |
779 | { | |
780 | struct trace_event_call *call = trace_probe_event_call(&ep->tp); | |
781 | ||
782 | call->flags = TRACE_EVENT_FL_EPROBE; | |
783 | call->event.funcs = &eprobe_funcs; | |
784 | call->class->fields_array = eprobe_fields_array; | |
785 | call->class->reg = eprobe_register; | |
786 | } | |
787 | ||
788 | static struct trace_event_call * | |
789 | find_and_get_event(const char *system, const char *event_name) | |
790 | { | |
791 | struct trace_event_call *tp_event; | |
792 | const char *name; | |
793 | ||
794 | list_for_each_entry(tp_event, &ftrace_events, list) { | |
795 | /* Skip other probes and ftrace events */ | |
796 | if (tp_event->flags & | |
797 | (TRACE_EVENT_FL_IGNORE_ENABLE | | |
798 | TRACE_EVENT_FL_KPROBE | | |
799 | TRACE_EVENT_FL_UPROBE | | |
800 | TRACE_EVENT_FL_EPROBE)) | |
801 | continue; | |
802 | if (!tp_event->class->system || | |
803 | strcmp(system, tp_event->class->system)) | |
804 | continue; | |
805 | name = trace_event_name(tp_event); | |
806 | if (!name || strcmp(event_name, name)) | |
807 | continue; | |
808 | if (!trace_event_try_get_ref(tp_event)) { | |
809 | return NULL; | |
810 | break; | |
811 | } | |
812 | return tp_event; | |
813 | break; | |
814 | } | |
815 | return NULL; | |
816 | } | |
817 | ||
818 | static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[], int i) | |
819 | { | |
820 | unsigned int flags = TPARG_FL_KERNEL | TPARG_FL_TPOINT; | |
821 | int ret; | |
822 | ||
823 | ret = traceprobe_parse_probe_arg(&ep->tp, i, argv[i], flags); | |
824 | if (ret) | |
825 | return ret; | |
826 | ||
2f63e5d2 | 827 | if (ep->tp.args[i].code->op == FETCH_OP_TP_ARG) { |
7491e2c4 | 828 | ret = trace_eprobe_tp_arg_update(ep, i); |
2f63e5d2 MHG |
829 | if (ret) |
830 | trace_probe_log_err(0, BAD_ATTACH_ARG); | |
831 | } | |
7491e2c4 | 832 | |
6a832ec3 SRG |
833 | /* Handle symbols "@" */ |
834 | if (!ret) | |
835 | ret = traceprobe_update_arg(&ep->tp.args[i]); | |
836 | ||
7491e2c4 TSV |
837 | return ret; |
838 | } | |
839 | ||
752be5c5 MHG |
840 | static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const char *argv[]) |
841 | { | |
342a4a2f | 842 | struct event_filter *dummy = NULL; |
752be5c5 MHG |
843 | int i, ret, len = 0; |
844 | char *p; | |
845 | ||
846 | if (argc == 0) { | |
847 | trace_probe_log_err(0, NO_EP_FILTER); | |
848 | return -EINVAL; | |
849 | } | |
850 | ||
851 | /* Recover the filter string */ | |
852 | for (i = 0; i < argc; i++) | |
853 | len += strlen(argv[i]) + 1; | |
854 | ||
855 | ep->filter_str = kzalloc(len, GFP_KERNEL); | |
856 | if (!ep->filter_str) | |
857 | return -ENOMEM; | |
858 | ||
859 | p = ep->filter_str; | |
860 | for (i = 0; i < argc; i++) { | |
c96abaec QF |
861 | if (i) |
862 | ret = snprintf(p, len, " %s", argv[i]); | |
863 | else | |
864 | ret = snprintf(p, len, "%s", argv[i]); | |
752be5c5 MHG |
865 | p += ret; |
866 | len -= ret; | |
867 | } | |
752be5c5 MHG |
868 | |
869 | /* | |
870 | * Ensure the filter string can be parsed correctly. Note, this | |
871 | * filter string is for the original event, not for the eprobe. | |
872 | */ | |
873 | ret = create_event_filter(top_trace_array(), ep->event, ep->filter_str, | |
874 | true, &dummy); | |
875 | free_event_filter(dummy); | |
876 | if (ret) | |
877 | goto error; | |
878 | ||
879 | return 0; | |
880 | error: | |
881 | kfree(ep->filter_str); | |
882 | ep->filter_str = NULL; | |
883 | return ret; | |
884 | } | |
885 | ||
7491e2c4 TSV |
886 | static int __trace_eprobe_create(int argc, const char *argv[]) |
887 | { | |
888 | /* | |
889 | * Argument syntax: | |
752be5c5 MHG |
890 | * e[:[GRP/][ENAME]] SYSTEM.EVENT [FETCHARGS] [if FILTER] |
891 | * Fetch args (no space): | |
7491e2c4 TSV |
892 | * <name>=$<field>[:TYPE] |
893 | */ | |
894 | const char *event = NULL, *group = EPROBE_EVENT_SYSTEM; | |
895 | const char *sys_event = NULL, *sys_name = NULL; | |
896 | struct trace_event_call *event_call; | |
897 | struct trace_eprobe *ep = NULL; | |
898 | char buf1[MAX_EVENT_NAME_LEN]; | |
899 | char buf2[MAX_EVENT_NAME_LEN]; | |
95c104c3 | 900 | char gbuf[MAX_EVENT_NAME_LEN]; |
752be5c5 MHG |
901 | int ret = 0, filter_idx = 0; |
902 | int i, filter_cnt; | |
7491e2c4 TSV |
903 | |
904 | if (argc < 2 || argv[0][0] != 'e') | |
905 | return -ECANCELED; | |
906 | ||
907 | trace_probe_log_init("event_probe", argc, argv); | |
908 | ||
909 | event = strchr(&argv[0][1], ':'); | |
910 | if (event) { | |
911 | event++; | |
95c104c3 | 912 | ret = traceprobe_parse_event_name(&event, &group, gbuf, |
7491e2c4 TSV |
913 | event - argv[0]); |
914 | if (ret) | |
915 | goto parse_error; | |
7491e2c4 | 916 | } |
7491e2c4 | 917 | |
b774926c | 918 | trace_probe_log_set_index(1); |
7491e2c4 | 919 | sys_event = argv[1]; |
95c104c3 | 920 | ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2, 0); |
d8a64313 | 921 | if (ret || !sys_event || !sys_name) { |
2f63e5d2 | 922 | trace_probe_log_err(0, NO_EVENT_INFO); |
7491e2c4 | 923 | goto parse_error; |
2f63e5d2 | 924 | } |
7491e2c4 | 925 | |
95c104c3 | 926 | if (!event) { |
dc399ade | 927 | strscpy(buf1, sys_event, MAX_EVENT_NAME_LEN); |
95c104c3 LY |
928 | event = buf1; |
929 | } | |
930 | ||
752be5c5 MHG |
931 | for (i = 2; i < argc; i++) { |
932 | if (!strcmp(argv[i], "if")) { | |
933 | filter_idx = i + 1; | |
934 | filter_cnt = argc - filter_idx; | |
935 | argc = i; | |
936 | break; | |
937 | } | |
938 | } | |
939 | ||
7491e2c4 TSV |
940 | mutex_lock(&event_mutex); |
941 | event_call = find_and_get_event(sys_name, sys_event); | |
942 | ep = alloc_event_probe(group, event, event_call, argc - 2); | |
943 | mutex_unlock(&event_mutex); | |
944 | ||
945 | if (IS_ERR(ep)) { | |
946 | ret = PTR_ERR(ep); | |
2f63e5d2 MHG |
947 | if (ret == -ENODEV) |
948 | trace_probe_log_err(0, BAD_ATTACH_EVENT); | |
ddcf906f | 949 | /* This must return -ENOMEM or missing event, else there is a bug */ |
7fa598f9 | 950 | WARN_ON_ONCE(ret != -ENOMEM && ret != -ENODEV); |
5615e088 DC |
951 | ep = NULL; |
952 | goto error; | |
7491e2c4 TSV |
953 | } |
954 | ||
752be5c5 MHG |
955 | if (filter_idx) { |
956 | trace_probe_log_set_index(filter_idx); | |
957 | ret = trace_eprobe_parse_filter(ep, filter_cnt, argv + filter_idx); | |
958 | if (ret) | |
959 | goto parse_error; | |
960 | } else | |
961 | ep->filter_str = NULL; | |
962 | ||
7491e2c4 TSV |
963 | argc -= 2; argv += 2; |
964 | /* parse arguments */ | |
965 | for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { | |
966 | trace_probe_log_set_index(i + 2); | |
967 | ret = trace_eprobe_tp_update_arg(ep, argv, i); | |
968 | if (ret) | |
969 | goto error; | |
970 | } | |
971 | ret = traceprobe_set_print_fmt(&ep->tp, PROBE_PRINT_EVENT); | |
972 | if (ret < 0) | |
973 | goto error; | |
974 | init_trace_eprobe_call(ep); | |
975 | mutex_lock(&event_mutex); | |
976 | ret = trace_probe_register_event_call(&ep->tp); | |
977 | if (ret) { | |
978 | if (ret == -EEXIST) { | |
979 | trace_probe_log_set_index(0); | |
980 | trace_probe_log_err(0, EVENT_EXIST); | |
981 | } | |
982 | mutex_unlock(&event_mutex); | |
983 | goto error; | |
984 | } | |
985 | ret = dyn_event_add(&ep->devent, &ep->tp.event->call); | |
986 | mutex_unlock(&event_mutex); | |
987 | return ret; | |
988 | parse_error: | |
989 | ret = -EINVAL; | |
990 | error: | |
991 | trace_event_probe_cleanup(ep); | |
992 | return ret; | |
993 | } | |
994 | ||
995 | /* | |
996 | * Register dynevent at core_initcall. This allows kernel to setup eprobe | |
997 | * events in postcore_initcall without tracefs. | |
998 | */ | |
999 | static __init int trace_events_eprobe_init_early(void) | |
1000 | { | |
1001 | int err = 0; | |
1002 | ||
1003 | err = dyn_event_register(&eprobe_dyn_event_ops); | |
1004 | if (err) | |
1005 | pr_warn("Could not register eprobe_dyn_event_ops\n"); | |
1006 | ||
1007 | return err; | |
1008 | } | |
1009 | core_initcall(trace_events_eprobe_init_early); |