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[cor.git] / kernel / trace / trace_kprobe.c
blob7f890262c8a3a4b71c01ac0a9c5f9146ed6a5223
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Kprobes-based tracing events
4 *
5 * Created by Masami Hiramatsu <mhiramat@redhat.com>
6 *
7 */
8 #define pr_fmt(fmt) "trace_kprobe: " fmt
9
10 #include <linux/security.h>
11 #include <linux/module.h>
12 #include <linux/uaccess.h>
13 #include <linux/rculist.h>
14 #include <linux/error-injection.h>
15
16 #include <asm/setup.h> /* for COMMAND_LINE_SIZE */
17
18 #include "trace_dynevent.h"
19 #include "trace_kprobe_selftest.h"
20 #include "trace_probe.h"
21 #include "trace_probe_tmpl.h"
22
23 #define KPROBE_EVENT_SYSTEM "kprobes"
24 #define KRETPROBE_MAXACTIVE_MAX 4096
25 #define MAX_KPROBE_CMDLINE_SIZE 1024
26
27 /* Kprobe early definition from command line */
28 static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
29 static bool kprobe_boot_events_enabled __initdata;
30
31 static int __init set_kprobe_boot_events(char *str)
32 {
33 strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
34 return 0;
35 }
36 __setup("kprobe_event=", set_kprobe_boot_events);
37
38 static int trace_kprobe_create(int argc, const char **argv);
39 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
40 static int trace_kprobe_release(struct dyn_event *ev);
41 static bool trace_kprobe_is_busy(struct dyn_event *ev);
42 static bool trace_kprobe_match(const char *system, const char *event,
43 int argc, const char **argv, struct dyn_event *ev);
44
45 static struct dyn_event_operations trace_kprobe_ops = {
46 .create = trace_kprobe_create,
47 .show = trace_kprobe_show,
48 .is_busy = trace_kprobe_is_busy,
49 .free = trace_kprobe_release,
50 .match = trace_kprobe_match,
51 };
52
53 /*
54 * Kprobe event core functions
55 */
56 struct trace_kprobe {
57 struct dyn_event devent;
58 struct kretprobe rp; /* Use rp.kp for kprobe use */
59 unsigned long __percpu *nhit;
60 const char *symbol; /* symbol name */
61 struct trace_probe tp;
62 };
63
64 static bool is_trace_kprobe(struct dyn_event *ev)
65 {
66 return ev->ops == &trace_kprobe_ops;
67 }
68
69 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
70 {
71 return container_of(ev, struct trace_kprobe, devent);
72 }
73
74 /**
75 * for_each_trace_kprobe - iterate over the trace_kprobe list
76 * @pos: the struct trace_kprobe * for each entry
77 * @dpos: the struct dyn_event * to use as a loop cursor
78 */
79 #define for_each_trace_kprobe(pos, dpos) \
80 for_each_dyn_event(dpos) \
81 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
82
83 #define SIZEOF_TRACE_KPROBE(n) \
84 (offsetof(struct trace_kprobe, tp.args) + \
85 (sizeof(struct probe_arg) * (n)))
86
87 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
88 {
89 return tk->rp.handler != NULL;
90 }
91
92 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
93 {
94 return tk->symbol ? tk->symbol : "unknown";
95 }
96
97 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
98 {
99 return tk->rp.kp.offset;
100 }
101
102 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
103 {
104 return !!(kprobe_gone(&tk->rp.kp));
105 }
106
107 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
108 struct module *mod)
109 {
110 int len = strlen(mod->name);
111 const char *name = trace_kprobe_symbol(tk);
112 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
113 }
114
115 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
116 {
117 char *p;
118 bool ret;
119
120 if (!tk->symbol)
121 return false;
122 p = strchr(tk->symbol, ':');
123 if (!p)
124 return true;
125 *p = '\0';
126 mutex_lock(&module_mutex);
127 ret = !!find_module(tk->symbol);
128 mutex_unlock(&module_mutex);
129 *p = ':';
130
131 return ret;
132 }
133
134 static bool trace_kprobe_is_busy(struct dyn_event *ev)
135 {
136 struct trace_kprobe *tk = to_trace_kprobe(ev);
137
138 return trace_probe_is_enabled(&tk->tp);
139 }
140
141 static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
142 int argc, const char **argv)
143 {
144 char buf[MAX_ARGSTR_LEN + 1];
145
146 if (!argc)
147 return true;
148
149 if (!tk->symbol)
150 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
151 else if (tk->rp.kp.offset)
152 snprintf(buf, sizeof(buf), "%s+%u",
153 trace_kprobe_symbol(tk), tk->rp.kp.offset);
154 else
155 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
156 if (strcmp(buf, argv[0]))
157 return false;
158 argc--; argv++;
159
160 return trace_probe_match_command_args(&tk->tp, argc, argv);
161 }
162
163 static bool trace_kprobe_match(const char *system, const char *event,
164 int argc, const char **argv, struct dyn_event *ev)
165 {
166 struct trace_kprobe *tk = to_trace_kprobe(ev);
167
168 return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
169 (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
170 trace_kprobe_match_command_head(tk, argc, argv);
171 }
172
173 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
174 {
175 unsigned long nhit = 0;
176 int cpu;
177
178 for_each_possible_cpu(cpu)
179 nhit += *per_cpu_ptr(tk->nhit, cpu);
180
181 return nhit;
182 }
183
184 static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
185 {
186 return !(list_empty(&tk->rp.kp.list) &&
187 hlist_unhashed(&tk->rp.kp.hlist));
188 }
189
190 /* Return 0 if it fails to find the symbol address */
191 static nokprobe_inline
192 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
193 {
194 unsigned long addr;
195
196 if (tk->symbol) {
197 addr = (unsigned long)
198 kallsyms_lookup_name(trace_kprobe_symbol(tk));
199 if (addr)
200 addr += tk->rp.kp.offset;
201 } else {
202 addr = (unsigned long)tk->rp.kp.addr;
203 }
204 return addr;
205 }
206
207 static nokprobe_inline struct trace_kprobe *
208 trace_kprobe_primary_from_call(struct trace_event_call *call)
209 {
210 struct trace_probe *tp;
211
212 tp = trace_probe_primary_from_call(call);
213 if (WARN_ON_ONCE(!tp))
214 return NULL;
215
216 return container_of(tp, struct trace_kprobe, tp);
217 }
218
219 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
220 {
221 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
222
223 return tk ? kprobe_on_func_entry(tk->rp.kp.addr,
224 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
225 tk->rp.kp.addr ? 0 : tk->rp.kp.offset) : false;
226 }
227
228 bool trace_kprobe_error_injectable(struct trace_event_call *call)
229 {
230 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
231
232 return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
233 false;
234 }
235
236 static int register_kprobe_event(struct trace_kprobe *tk);
237 static int unregister_kprobe_event(struct trace_kprobe *tk);
238
239 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
240 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
241 struct pt_regs *regs);
242
243 static void free_trace_kprobe(struct trace_kprobe *tk)
244 {
245 if (tk) {
246 trace_probe_cleanup(&tk->tp);
247 kfree(tk->symbol);
248 free_percpu(tk->nhit);
249 kfree(tk);
250 }
251 }
252
253 /*
254 * Allocate new trace_probe and initialize it (including kprobes).
255 */
256 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
257 const char *event,
258 void *addr,
259 const char *symbol,
260 unsigned long offs,
261 int maxactive,
262 int nargs, bool is_return)
263 {
264 struct trace_kprobe *tk;
265 int ret = -ENOMEM;
266
267 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
268 if (!tk)
269 return ERR_PTR(ret);
270
271 tk->nhit = alloc_percpu(unsigned long);
272 if (!tk->nhit)
273 goto error;
274
275 if (symbol) {
276 tk->symbol = kstrdup(symbol, GFP_KERNEL);
277 if (!tk->symbol)
278 goto error;
279 tk->rp.kp.symbol_name = tk->symbol;
280 tk->rp.kp.offset = offs;
281 } else
282 tk->rp.kp.addr = addr;
283
284 if (is_return)
285 tk->rp.handler = kretprobe_dispatcher;
286 else
287 tk->rp.kp.pre_handler = kprobe_dispatcher;
288
289 tk->rp.maxactive = maxactive;
290 INIT_HLIST_NODE(&tk->rp.kp.hlist);
291 INIT_LIST_HEAD(&tk->rp.kp.list);
292
293 ret = trace_probe_init(&tk->tp, event, group);
294 if (ret < 0)
295 goto error;
296
297 dyn_event_init(&tk->devent, &trace_kprobe_ops);
298 return tk;
299 error:
300 free_trace_kprobe(tk);
301 return ERR_PTR(ret);
302 }
303
304 static struct trace_kprobe *find_trace_kprobe(const char *event,
305 const char *group)
306 {
307 struct dyn_event *pos;
308 struct trace_kprobe *tk;
309
310 for_each_trace_kprobe(tk, pos)
311 if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
312 strcmp(trace_probe_group_name(&tk->tp), group) == 0)
313 return tk;
314 return NULL;
315 }
316
317 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
318 {
319 int ret = 0;
320
321 if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
322 if (trace_kprobe_is_return(tk))
323 ret = enable_kretprobe(&tk->rp);
324 else
325 ret = enable_kprobe(&tk->rp.kp);
326 }
327
328 return ret;
329 }
330
331 static void __disable_trace_kprobe(struct trace_probe *tp)
332 {
333 struct trace_probe *pos;
334 struct trace_kprobe *tk;
335
336 list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
337 tk = container_of(pos, struct trace_kprobe, tp);
338 if (!trace_kprobe_is_registered(tk))
339 continue;
340 if (trace_kprobe_is_return(tk))
341 disable_kretprobe(&tk->rp);
342 else
343 disable_kprobe(&tk->rp.kp);
344 }
345 }
346
347 /*
348 * Enable trace_probe
349 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
350 */
351 static int enable_trace_kprobe(struct trace_event_call *call,
352 struct trace_event_file *file)
353 {
354 struct trace_probe *pos, *tp;
355 struct trace_kprobe *tk;
356 bool enabled;
357 int ret = 0;
358
359 tp = trace_probe_primary_from_call(call);
360 if (WARN_ON_ONCE(!tp))
361 return -ENODEV;
362 enabled = trace_probe_is_enabled(tp);
363
364 /* This also changes "enabled" state */
365 if (file) {
366 ret = trace_probe_add_file(tp, file);
367 if (ret)
368 return ret;
369 } else
370 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
371
372 if (enabled)
373 return 0;
374
375 list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
376 tk = container_of(pos, struct trace_kprobe, tp);
377 if (trace_kprobe_has_gone(tk))
378 continue;
379 ret = __enable_trace_kprobe(tk);
380 if (ret)
381 break;
382 enabled = true;
383 }
384
385 if (ret) {
386 /* Failed to enable one of them. Roll back all */
387 if (enabled)
388 __disable_trace_kprobe(tp);
389 if (file)
390 trace_probe_remove_file(tp, file);
391 else
392 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
393 }
394
395 return ret;
396 }
397
398 /*
399 * Disable trace_probe
400 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
401 */
402 static int disable_trace_kprobe(struct trace_event_call *call,
403 struct trace_event_file *file)
404 {
405 struct trace_probe *tp;
406
407 tp = trace_probe_primary_from_call(call);
408 if (WARN_ON_ONCE(!tp))
409 return -ENODEV;
410
411 if (file) {
412 if (!trace_probe_get_file_link(tp, file))
413 return -ENOENT;
414 if (!trace_probe_has_single_file(tp))
415 goto out;
416 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
417 } else
418 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
419
420 if (!trace_probe_is_enabled(tp))
421 __disable_trace_kprobe(tp);
422
423 out:
424 if (file)
425 /*
426 * Synchronization is done in below function. For perf event,
427 * file == NULL and perf_trace_event_unreg() calls
428 * tracepoint_synchronize_unregister() to ensure synchronize
429 * event. We don't need to care about it.
430 */
431 trace_probe_remove_file(tp, file);
432
433 return 0;
434 }
435
436 #if defined(CONFIG_KPROBES_ON_FTRACE) && \
437 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
438 static bool __within_notrace_func(unsigned long addr)
439 {
440 unsigned long offset, size;
441
442 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
443 return false;
444
445 /* Get the entry address of the target function */
446 addr -= offset;
447
448 /*
449 * Since ftrace_location_range() does inclusive range check, we need
450 * to subtract 1 byte from the end address.
451 */
452 return !ftrace_location_range(addr, addr + size - 1);
453 }
454
455 static bool within_notrace_func(struct trace_kprobe *tk)
456 {
457 unsigned long addr = addr = trace_kprobe_address(tk);
458 char symname[KSYM_NAME_LEN], *p;
459
460 if (!__within_notrace_func(addr))
461 return false;
462
463 /* Check if the address is on a suffixed-symbol */
464 if (!lookup_symbol_name(addr, symname)) {
465 p = strchr(symname, '.');
466 if (!p)
467 return true;
468 *p = '\0';
469 addr = (unsigned long)kprobe_lookup_name(symname, 0);
470 if (addr)
471 return __within_notrace_func(addr);
472 }
473
474 return true;
475 }
476 #else
477 #define within_notrace_func(tk) (false)
478 #endif
479
480 /* Internal register function - just handle k*probes and flags */
481 static int __register_trace_kprobe(struct trace_kprobe *tk)
482 {
483 int i, ret;
484
485 ret = security_locked_down(LOCKDOWN_KPROBES);
486 if (ret)
487 return ret;
488
489 if (trace_kprobe_is_registered(tk))
490 return -EINVAL;
491
492 if (within_notrace_func(tk)) {
493 pr_warn("Could not probe notrace function %s\n",
494 trace_kprobe_symbol(tk));
495 return -EINVAL;
496 }
497
498 for (i = 0; i < tk->tp.nr_args; i++) {
499 ret = traceprobe_update_arg(&tk->tp.args[i]);
500 if (ret)
501 return ret;
502 }
503
504 /* Set/clear disabled flag according to tp->flag */
505 if (trace_probe_is_enabled(&tk->tp))
506 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
507 else
508 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
509
510 if (trace_kprobe_is_return(tk))
511 ret = register_kretprobe(&tk->rp);
512 else
513 ret = register_kprobe(&tk->rp.kp);
514
515 return ret;
516 }
517
518 /* Internal unregister function - just handle k*probes and flags */
519 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
520 {
521 if (trace_kprobe_is_registered(tk)) {
522 if (trace_kprobe_is_return(tk))
523 unregister_kretprobe(&tk->rp);
524 else
525 unregister_kprobe(&tk->rp.kp);
526 /* Cleanup kprobe for reuse and mark it unregistered */
527 INIT_HLIST_NODE(&tk->rp.kp.hlist);
528 INIT_LIST_HEAD(&tk->rp.kp.list);
529 if (tk->rp.kp.symbol_name)
530 tk->rp.kp.addr = NULL;
531 }
532 }
533
534 /* Unregister a trace_probe and probe_event */
535 static int unregister_trace_kprobe(struct trace_kprobe *tk)
536 {
537 /* If other probes are on the event, just unregister kprobe */
538 if (trace_probe_has_sibling(&tk->tp))
539 goto unreg;
540
541 /* Enabled event can not be unregistered */
542 if (trace_probe_is_enabled(&tk->tp))
543 return -EBUSY;
544
545 /* Will fail if probe is being used by ftrace or perf */
546 if (unregister_kprobe_event(tk))
547 return -EBUSY;
548
549 unreg:
550 __unregister_trace_kprobe(tk);
551 dyn_event_remove(&tk->devent);
552 trace_probe_unlink(&tk->tp);
553
554 return 0;
555 }
556
557 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
558 struct trace_kprobe *comp)
559 {
560 struct trace_probe_event *tpe = orig->tp.event;
561 struct trace_probe *pos;
562 int i;
563
564 list_for_each_entry(pos, &tpe->probes, list) {
565 orig = container_of(pos, struct trace_kprobe, tp);
566 if (strcmp(trace_kprobe_symbol(orig),
567 trace_kprobe_symbol(comp)) ||
568 trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
569 continue;
570
571 /*
572 * trace_probe_compare_arg_type() ensured that nr_args and
573 * each argument name and type are same. Let's compare comm.
574 */
575 for (i = 0; i < orig->tp.nr_args; i++) {
576 if (strcmp(orig->tp.args[i].comm,
577 comp->tp.args[i].comm))
578 break;
579 }
580
581 if (i == orig->tp.nr_args)
582 return true;
583 }
584
585 return false;
586 }
587
588 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
589 {
590 int ret;
591
592 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
593 if (ret) {
594 /* Note that argument starts index = 2 */
595 trace_probe_log_set_index(ret + 1);
596 trace_probe_log_err(0, DIFF_ARG_TYPE);
597 return -EEXIST;
598 }
599 if (trace_kprobe_has_same_kprobe(to, tk)) {
600 trace_probe_log_set_index(0);
601 trace_probe_log_err(0, SAME_PROBE);
602 return -EEXIST;
603 }
604
605 /* Append to existing event */
606 ret = trace_probe_append(&tk->tp, &to->tp);
607 if (ret)
608 return ret;
609
610 /* Register k*probe */
611 ret = __register_trace_kprobe(tk);
612 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
613 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
614 ret = 0;
615 }
616
617 if (ret)
618 trace_probe_unlink(&tk->tp);
619 else
620 dyn_event_add(&tk->devent);
621
622 return ret;
623 }
624
625 /* Register a trace_probe and probe_event */
626 static int register_trace_kprobe(struct trace_kprobe *tk)
627 {
628 struct trace_kprobe *old_tk;
629 int ret;
630
631 mutex_lock(&event_mutex);
632
633 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
634 trace_probe_group_name(&tk->tp));
635 if (old_tk) {
636 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
637 trace_probe_log_set_index(0);
638 trace_probe_log_err(0, DIFF_PROBE_TYPE);
639 ret = -EEXIST;
640 } else {
641 ret = append_trace_kprobe(tk, old_tk);
642 }
643 goto end;
644 }
645
646 /* Register new event */
647 ret = register_kprobe_event(tk);
648 if (ret) {
649 pr_warn("Failed to register probe event(%d)\n", ret);
650 goto end;
651 }
652
653 /* Register k*probe */
654 ret = __register_trace_kprobe(tk);
655 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
656 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
657 ret = 0;
658 }
659
660 if (ret < 0)
661 unregister_kprobe_event(tk);
662 else
663 dyn_event_add(&tk->devent);
664
665 end:
666 mutex_unlock(&event_mutex);
667 return ret;
668 }
669
670 /* Module notifier call back, checking event on the module */
671 static int trace_kprobe_module_callback(struct notifier_block *nb,
672 unsigned long val, void *data)
673 {
674 struct module *mod = data;
675 struct dyn_event *pos;
676 struct trace_kprobe *tk;
677 int ret;
678
679 if (val != MODULE_STATE_COMING)
680 return NOTIFY_DONE;
681
682 /* Update probes on coming module */
683 mutex_lock(&event_mutex);
684 for_each_trace_kprobe(tk, pos) {
685 if (trace_kprobe_within_module(tk, mod)) {
686 /* Don't need to check busy - this should have gone. */
687 __unregister_trace_kprobe(tk);
688 ret = __register_trace_kprobe(tk);
689 if (ret)
690 pr_warn("Failed to re-register probe %s on %s: %d\n",
691 trace_probe_name(&tk->tp),
692 mod->name, ret);
693 }
694 }
695 mutex_unlock(&event_mutex);
696
697 return NOTIFY_DONE;
698 }
699
700 static struct notifier_block trace_kprobe_module_nb = {
701 .notifier_call = trace_kprobe_module_callback,
702 .priority = 1 /* Invoked after kprobe module callback */
703 };
704
705 /* Convert certain expected symbols into '_' when generating event names */
706 static inline void sanitize_event_name(char *name)
707 {
708 while (*name++ != '\0')
709 if (*name == ':' || *name == '.')
710 *name = '_';
711 }
712
713 static int trace_kprobe_create(int argc, const char *argv[])
714 {
715 /*
716 * Argument syntax:
717 * - Add kprobe:
718 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
719 * - Add kretprobe:
720 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
721 * Fetch args:
722 * $retval : fetch return value
723 * $stack : fetch stack address
724 * $stackN : fetch Nth of stack (N:0-)
725 * $comm : fetch current task comm
726 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
727 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
728 * %REG : fetch register REG
729 * Dereferencing memory fetch:
730 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
731 * Alias name of args:
732 * NAME=FETCHARG : set NAME as alias of FETCHARG.
733 * Type of args:
734 * FETCHARG:TYPE : use TYPE instead of unsigned long.
735 */
736 struct trace_kprobe *tk = NULL;
737 int i, len, ret = 0;
738 bool is_return = false;
739 char *symbol = NULL, *tmp = NULL;
740 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
741 int maxactive = 0;
742 long offset = 0;
743 void *addr = NULL;
744 char buf[MAX_EVENT_NAME_LEN];
745 unsigned int flags = TPARG_FL_KERNEL;
746
747 switch (argv[0][0]) {
748 case 'r':
749 is_return = true;
750 flags |= TPARG_FL_RETURN;
751 break;
752 case 'p':
753 break;
754 default:
755 return -ECANCELED;
756 }
757 if (argc < 2)
758 return -ECANCELED;
759
760 trace_probe_log_init("trace_kprobe", argc, argv);
761
762 event = strchr(&argv[0][1], ':');
763 if (event)
764 event++;
765
766 if (isdigit(argv[0][1])) {
767 if (!is_return) {
768 trace_probe_log_err(1, MAXACT_NO_KPROBE);
769 goto parse_error;
770 }
771 if (event)
772 len = event - &argv[0][1] - 1;
773 else
774 len = strlen(&argv[0][1]);
775 if (len > MAX_EVENT_NAME_LEN - 1) {
776 trace_probe_log_err(1, BAD_MAXACT);
777 goto parse_error;
778 }
779 memcpy(buf, &argv[0][1], len);
780 buf[len] = '\0';
781 ret = kstrtouint(buf, 0, &maxactive);
782 if (ret || !maxactive) {
783 trace_probe_log_err(1, BAD_MAXACT);
784 goto parse_error;
785 }
786 /* kretprobes instances are iterated over via a list. The
787 * maximum should stay reasonable.
788 */
789 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
790 trace_probe_log_err(1, MAXACT_TOO_BIG);
791 goto parse_error;
792 }
793 }
794
795 /* try to parse an address. if that fails, try to read the
796 * input as a symbol. */
797 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
798 trace_probe_log_set_index(1);
799 /* Check whether uprobe event specified */
800 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
801 ret = -ECANCELED;
802 goto error;
803 }
804 /* a symbol specified */
805 symbol = kstrdup(argv[1], GFP_KERNEL);
806 if (!symbol)
807 return -ENOMEM;
808 /* TODO: support .init module functions */
809 ret = traceprobe_split_symbol_offset(symbol, &offset);
810 if (ret || offset < 0 || offset > UINT_MAX) {
811 trace_probe_log_err(0, BAD_PROBE_ADDR);
812 goto parse_error;
813 }
814 if (kprobe_on_func_entry(NULL, symbol, offset))
815 flags |= TPARG_FL_FENTRY;
816 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
817 trace_probe_log_err(0, BAD_RETPROBE);
818 goto parse_error;
819 }
820 }
821
822 trace_probe_log_set_index(0);
823 if (event) {
824 ret = traceprobe_parse_event_name(&event, &group, buf,
825 event - argv[0]);
826 if (ret)
827 goto parse_error;
828 } else {
829 /* Make a new event name */
830 if (symbol)
831 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
832 is_return ? 'r' : 'p', symbol, offset);
833 else
834 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
835 is_return ? 'r' : 'p', addr);
836 sanitize_event_name(buf);
837 event = buf;
838 }
839
840 /* setup a probe */
841 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
842 argc - 2, is_return);
843 if (IS_ERR(tk)) {
844 ret = PTR_ERR(tk);
845 /* This must return -ENOMEM, else there is a bug */
846 WARN_ON_ONCE(ret != -ENOMEM);
847 goto out; /* We know tk is not allocated */
848 }
849 argc -= 2; argv += 2;
850
851 /* parse arguments */
852 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
853 tmp = kstrdup(argv[i], GFP_KERNEL);
854 if (!tmp) {
855 ret = -ENOMEM;
856 goto error;
857 }
858
859 trace_probe_log_set_index(i + 2);
860 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
861 kfree(tmp);
862 if (ret)
863 goto error; /* This can be -ENOMEM */
864 }
865
866 ret = traceprobe_set_print_fmt(&tk->tp, is_return);
867 if (ret < 0)
868 goto error;
869
870 ret = register_trace_kprobe(tk);
871 if (ret) {
872 trace_probe_log_set_index(1);
873 if (ret == -EILSEQ)
874 trace_probe_log_err(0, BAD_INSN_BNDRY);
875 else if (ret == -ENOENT)
876 trace_probe_log_err(0, BAD_PROBE_ADDR);
877 else if (ret != -ENOMEM && ret != -EEXIST)
878 trace_probe_log_err(0, FAIL_REG_PROBE);
879 goto error;
880 }
881
882 out:
883 trace_probe_log_clear();
884 kfree(symbol);
885 return ret;
886
887 parse_error:
888 ret = -EINVAL;
889 error:
890 free_trace_kprobe(tk);
891 goto out;
892 }
893
894 static int create_or_delete_trace_kprobe(int argc, char **argv)
895 {
896 int ret;
897
898 if (argv[0][0] == '-')
899 return dyn_event_release(argc, argv, &trace_kprobe_ops);
900
901 ret = trace_kprobe_create(argc, (const char **)argv);
902 return ret == -ECANCELED ? -EINVAL : ret;
903 }
904
905 static int trace_kprobe_release(struct dyn_event *ev)
906 {
907 struct trace_kprobe *tk = to_trace_kprobe(ev);
908 int ret = unregister_trace_kprobe(tk);
909
910 if (!ret)
911 free_trace_kprobe(tk);
912 return ret;
913 }
914
915 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
916 {
917 struct trace_kprobe *tk = to_trace_kprobe(ev);
918 int i;
919
920 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
921 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
922 trace_probe_name(&tk->tp));
923
924 if (!tk->symbol)
925 seq_printf(m, " 0x%p", tk->rp.kp.addr);
926 else if (tk->rp.kp.offset)
927 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
928 tk->rp.kp.offset);
929 else
930 seq_printf(m, " %s", trace_kprobe_symbol(tk));
931
932 for (i = 0; i < tk->tp.nr_args; i++)
933 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
934 seq_putc(m, '\n');
935
936 return 0;
937 }
938
939 static int probes_seq_show(struct seq_file *m, void *v)
940 {
941 struct dyn_event *ev = v;
942
943 if (!is_trace_kprobe(ev))
944 return 0;
945
946 return trace_kprobe_show(m, ev);
947 }
948
949 static const struct seq_operations probes_seq_op = {
950 .start = dyn_event_seq_start,
951 .next = dyn_event_seq_next,
952 .stop = dyn_event_seq_stop,
953 .show = probes_seq_show
954 };
955
956 static int probes_open(struct inode *inode, struct file *file)
957 {
958 int ret;
959
960 ret = security_locked_down(LOCKDOWN_TRACEFS);
961 if (ret)
962 return ret;
963
964 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
965 ret = dyn_events_release_all(&trace_kprobe_ops);
966 if (ret < 0)
967 return ret;
968 }
969
970 return seq_open(file, &probes_seq_op);
971 }
972
973 static ssize_t probes_write(struct file *file, const char __user *buffer,
974 size_t count, loff_t *ppos)
975 {
976 return trace_parse_run_command(file, buffer, count, ppos,
977 create_or_delete_trace_kprobe);
978 }
979
980 static const struct file_operations kprobe_events_ops = {
981 .owner = THIS_MODULE,
982 .open = probes_open,
983 .read = seq_read,
984 .llseek = seq_lseek,
985 .release = seq_release,
986 .write = probes_write,
987 };
988
989 /* Probes profiling interfaces */
990 static int probes_profile_seq_show(struct seq_file *m, void *v)
991 {
992 struct dyn_event *ev = v;
993 struct trace_kprobe *tk;
994
995 if (!is_trace_kprobe(ev))
996 return 0;
997
998 tk = to_trace_kprobe(ev);
999 seq_printf(m, " %-44s %15lu %15lu\n",
1000 trace_probe_name(&tk->tp),
1001 trace_kprobe_nhit(tk),
1002 tk->rp.kp.nmissed);
1003
1004 return 0;
1005 }
1006
1007 static const struct seq_operations profile_seq_op = {
1008 .start = dyn_event_seq_start,
1009 .next = dyn_event_seq_next,
1010 .stop = dyn_event_seq_stop,
1011 .show = probes_profile_seq_show
1012 };
1013
1014 static int profile_open(struct inode *inode, struct file *file)
1015 {
1016 int ret;
1017
1018 ret = security_locked_down(LOCKDOWN_TRACEFS);
1019 if (ret)
1020 return ret;
1021
1022 return seq_open(file, &profile_seq_op);
1023 }
1024
1025 static const struct file_operations kprobe_profile_ops = {
1026 .owner = THIS_MODULE,
1027 .open = profile_open,
1028 .read = seq_read,
1029 .llseek = seq_lseek,
1030 .release = seq_release,
1031 };
1032
1033 /* Kprobe specific fetch functions */
1034
1035 /* Return the length of string -- including null terminal byte */
1036 static nokprobe_inline int
1037 fetch_store_strlen(unsigned long addr)
1038 {
1039 int ret, len = 0;
1040 u8 c;
1041
1042 do {
1043 ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
1044 len++;
1045 } while (c && ret == 0 && len < MAX_STRING_SIZE);
1046
1047 return (ret < 0) ? ret : len;
1048 }
1049
1050 /* Return the length of string -- including null terminal byte */
1051 static nokprobe_inline int
1052 fetch_store_strlen_user(unsigned long addr)
1053 {
1054 const void __user *uaddr = (__force const void __user *)addr;
1055
1056 return strnlen_unsafe_user(uaddr, MAX_STRING_SIZE);
1057 }
1058
1059 /*
1060 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
1061 * length and relative data location.
1062 */
1063 static nokprobe_inline int
1064 fetch_store_string(unsigned long addr, void *dest, void *base)
1065 {
1066 int maxlen = get_loc_len(*(u32 *)dest);
1067 void *__dest;
1068 long ret;
1069
1070 if (unlikely(!maxlen))
1071 return -ENOMEM;
1072
1073 __dest = get_loc_data(dest, base);
1074
1075 /*
1076 * Try to get string again, since the string can be changed while
1077 * probing.
1078 */
1079 ret = strncpy_from_unsafe(__dest, (void *)addr, maxlen);
1080 if (ret >= 0)
1081 *(u32 *)dest = make_data_loc(ret, __dest - base);
1082
1083 return ret;
1084 }
1085
1086 /*
1087 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
1088 * with max length and relative data location.
1089 */
1090 static nokprobe_inline int
1091 fetch_store_string_user(unsigned long addr, void *dest, void *base)
1092 {
1093 const void __user *uaddr = (__force const void __user *)addr;
1094 int maxlen = get_loc_len(*(u32 *)dest);
1095 void *__dest;
1096 long ret;
1097
1098 if (unlikely(!maxlen))
1099 return -ENOMEM;
1100
1101 __dest = get_loc_data(dest, base);
1102
1103 ret = strncpy_from_unsafe_user(__dest, uaddr, maxlen);
1104 if (ret >= 0)
1105 *(u32 *)dest = make_data_loc(ret, __dest - base);
1106
1107 return ret;
1108 }
1109
1110 static nokprobe_inline int
1111 probe_mem_read(void *dest, void *src, size_t size)
1112 {
1113 return probe_kernel_read(dest, src, size);
1114 }
1115
1116 static nokprobe_inline int
1117 probe_mem_read_user(void *dest, void *src, size_t size)
1118 {
1119 const void __user *uaddr = (__force const void __user *)src;
1120
1121 return probe_user_read(dest, uaddr, size);
1122 }
1123
1124 /* Note that we don't verify it, since the code does not come from user space */
1125 static int
1126 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
1127 void *base)
1128 {
1129 unsigned long val;
1130
1131 retry:
1132 /* 1st stage: get value from context */
1133 switch (code->op) {
1134 case FETCH_OP_REG:
1135 val = regs_get_register(regs, code->param);
1136 break;
1137 case FETCH_OP_STACK:
1138 val = regs_get_kernel_stack_nth(regs, code->param);
1139 break;
1140 case FETCH_OP_STACKP:
1141 val = kernel_stack_pointer(regs);
1142 break;
1143 case FETCH_OP_RETVAL:
1144 val = regs_return_value(regs);
1145 break;
1146 case FETCH_OP_IMM:
1147 val = code->immediate;
1148 break;
1149 case FETCH_OP_COMM:
1150 val = (unsigned long)current->comm;
1151 break;
1152 case FETCH_OP_DATA:
1153 val = (unsigned long)code->data;
1154 break;
1155 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1156 case FETCH_OP_ARG:
1157 val = regs_get_kernel_argument(regs, code->param);
1158 break;
1159 #endif
1160 case FETCH_NOP_SYMBOL: /* Ignore a place holder */
1161 code++;
1162 goto retry;
1163 default:
1164 return -EILSEQ;
1165 }
1166 code++;
1167
1168 return process_fetch_insn_bottom(code, val, dest, base);
1169 }
1170 NOKPROBE_SYMBOL(process_fetch_insn)
1171
1172 /* Kprobe handler */
1173 static nokprobe_inline void
1174 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1175 struct trace_event_file *trace_file)
1176 {
1177 struct kprobe_trace_entry_head *entry;
1178 struct ring_buffer_event *event;
1179 struct ring_buffer *buffer;
1180 int size, dsize, pc;
1181 unsigned long irq_flags;
1182 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1183
1184 WARN_ON(call != trace_file->event_call);
1185
1186 if (trace_trigger_soft_disabled(trace_file))
1187 return;
1188
1189 local_save_flags(irq_flags);
1190 pc = preempt_count();
1191
1192 dsize = __get_data_size(&tk->tp, regs);
1193 size = sizeof(*entry) + tk->tp.size + dsize;
1194
1195 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1196 call->event.type,
1197 size, irq_flags, pc);
1198 if (!event)
1199 return;
1200
1201 entry = ring_buffer_event_data(event);
1202 entry->ip = (unsigned long)tk->rp.kp.addr;
1203 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1204
1205 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1206 entry, irq_flags, pc, regs);
1207 }
1208
1209 static void
1210 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1211 {
1212 struct event_file_link *link;
1213
1214 trace_probe_for_each_link_rcu(link, &tk->tp)
1215 __kprobe_trace_func(tk, regs, link->file);
1216 }
1217 NOKPROBE_SYMBOL(kprobe_trace_func);
1218
1219 /* Kretprobe handler */
1220 static nokprobe_inline void
1221 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1222 struct pt_regs *regs,
1223 struct trace_event_file *trace_file)
1224 {
1225 struct kretprobe_trace_entry_head *entry;
1226 struct ring_buffer_event *event;
1227 struct ring_buffer *buffer;
1228 int size, pc, dsize;
1229 unsigned long irq_flags;
1230 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1231
1232 WARN_ON(call != trace_file->event_call);
1233
1234 if (trace_trigger_soft_disabled(trace_file))
1235 return;
1236
1237 local_save_flags(irq_flags);
1238 pc = preempt_count();
1239
1240 dsize = __get_data_size(&tk->tp, regs);
1241 size = sizeof(*entry) + tk->tp.size + dsize;
1242
1243 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1244 call->event.type,
1245 size, irq_flags, pc);
1246 if (!event)
1247 return;
1248
1249 entry = ring_buffer_event_data(event);
1250 entry->func = (unsigned long)tk->rp.kp.addr;
1251 entry->ret_ip = (unsigned long)ri->ret_addr;
1252 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1253
1254 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1255 entry, irq_flags, pc, regs);
1256 }
1257
1258 static void
1259 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1260 struct pt_regs *regs)
1261 {
1262 struct event_file_link *link;
1263
1264 trace_probe_for_each_link_rcu(link, &tk->tp)
1265 __kretprobe_trace_func(tk, ri, regs, link->file);
1266 }
1267 NOKPROBE_SYMBOL(kretprobe_trace_func);
1268
1269 /* Event entry printers */
1270 static enum print_line_t
1271 print_kprobe_event(struct trace_iterator *iter, int flags,
1272 struct trace_event *event)
1273 {
1274 struct kprobe_trace_entry_head *field;
1275 struct trace_seq *s = &iter->seq;
1276 struct trace_probe *tp;
1277
1278 field = (struct kprobe_trace_entry_head *)iter->ent;
1279 tp = trace_probe_primary_from_call(
1280 container_of(event, struct trace_event_call, event));
1281 if (WARN_ON_ONCE(!tp))
1282 goto out;
1283
1284 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1285
1286 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1287 goto out;
1288
1289 trace_seq_putc(s, ')');
1290
1291 if (print_probe_args(s, tp->args, tp->nr_args,
1292 (u8 *)&field[1], field) < 0)
1293 goto out;
1294
1295 trace_seq_putc(s, '\n');
1296 out:
1297 return trace_handle_return(s);
1298 }
1299
1300 static enum print_line_t
1301 print_kretprobe_event(struct trace_iterator *iter, int flags,
1302 struct trace_event *event)
1303 {
1304 struct kretprobe_trace_entry_head *field;
1305 struct trace_seq *s = &iter->seq;
1306 struct trace_probe *tp;
1307
1308 field = (struct kretprobe_trace_entry_head *)iter->ent;
1309 tp = trace_probe_primary_from_call(
1310 container_of(event, struct trace_event_call, event));
1311 if (WARN_ON_ONCE(!tp))
1312 goto out;
1313
1314 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1315
1316 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1317 goto out;
1318
1319 trace_seq_puts(s, " <- ");
1320
1321 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1322 goto out;
1323
1324 trace_seq_putc(s, ')');
1325
1326 if (print_probe_args(s, tp->args, tp->nr_args,
1327 (u8 *)&field[1], field) < 0)
1328 goto out;
1329
1330 trace_seq_putc(s, '\n');
1331
1332 out:
1333 return trace_handle_return(s);
1334 }
1335
1336
1337 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1338 {
1339 int ret;
1340 struct kprobe_trace_entry_head field;
1341 struct trace_probe *tp;
1342
1343 tp = trace_probe_primary_from_call(event_call);
1344 if (WARN_ON_ONCE(!tp))
1345 return -ENOENT;
1346
1347 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1348
1349 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1350 }
1351
1352 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1353 {
1354 int ret;
1355 struct kretprobe_trace_entry_head field;
1356 struct trace_probe *tp;
1357
1358 tp = trace_probe_primary_from_call(event_call);
1359 if (WARN_ON_ONCE(!tp))
1360 return -ENOENT;
1361
1362 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1363 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1364
1365 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1366 }
1367
1368 #ifdef CONFIG_PERF_EVENTS
1369
1370 /* Kprobe profile handler */
1371 static int
1372 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1373 {
1374 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1375 struct kprobe_trace_entry_head *entry;
1376 struct hlist_head *head;
1377 int size, __size, dsize;
1378 int rctx;
1379
1380 if (bpf_prog_array_valid(call)) {
1381 unsigned long orig_ip = instruction_pointer(regs);
1382 int ret;
1383
1384 ret = trace_call_bpf(call, regs);
1385
1386 /*
1387 * We need to check and see if we modified the pc of the
1388 * pt_regs, and if so return 1 so that we don't do the
1389 * single stepping.
1390 */
1391 if (orig_ip != instruction_pointer(regs))
1392 return 1;
1393 if (!ret)
1394 return 0;
1395 }
1396
1397 head = this_cpu_ptr(call->perf_events);
1398 if (hlist_empty(head))
1399 return 0;
1400
1401 dsize = __get_data_size(&tk->tp, regs);
1402 __size = sizeof(*entry) + tk->tp.size + dsize;
1403 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1404 size -= sizeof(u32);
1405
1406 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1407 if (!entry)
1408 return 0;
1409
1410 entry->ip = (unsigned long)tk->rp.kp.addr;
1411 memset(&entry[1], 0, dsize);
1412 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1413 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1414 head, NULL);
1415 return 0;
1416 }
1417 NOKPROBE_SYMBOL(kprobe_perf_func);
1418
1419 /* Kretprobe profile handler */
1420 static void
1421 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1422 struct pt_regs *regs)
1423 {
1424 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1425 struct kretprobe_trace_entry_head *entry;
1426 struct hlist_head *head;
1427 int size, __size, dsize;
1428 int rctx;
1429
1430 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1431 return;
1432
1433 head = this_cpu_ptr(call->perf_events);
1434 if (hlist_empty(head))
1435 return;
1436
1437 dsize = __get_data_size(&tk->tp, regs);
1438 __size = sizeof(*entry) + tk->tp.size + dsize;
1439 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1440 size -= sizeof(u32);
1441
1442 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1443 if (!entry)
1444 return;
1445
1446 entry->func = (unsigned long)tk->rp.kp.addr;
1447 entry->ret_ip = (unsigned long)ri->ret_addr;
1448 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1449 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1450 head, NULL);
1451 }
1452 NOKPROBE_SYMBOL(kretprobe_perf_func);
1453
1454 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1455 const char **symbol, u64 *probe_offset,
1456 u64 *probe_addr, bool perf_type_tracepoint)
1457 {
1458 const char *pevent = trace_event_name(event->tp_event);
1459 const char *group = event->tp_event->class->system;
1460 struct trace_kprobe *tk;
1461
1462 if (perf_type_tracepoint)
1463 tk = find_trace_kprobe(pevent, group);
1464 else
1465 tk = event->tp_event->data;
1466 if (!tk)
1467 return -EINVAL;
1468
1469 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1470 : BPF_FD_TYPE_KPROBE;
1471 if (tk->symbol) {
1472 *symbol = tk->symbol;
1473 *probe_offset = tk->rp.kp.offset;
1474 *probe_addr = 0;
1475 } else {
1476 *symbol = NULL;
1477 *probe_offset = 0;
1478 *probe_addr = (unsigned long)tk->rp.kp.addr;
1479 }
1480 return 0;
1481 }
1482 #endif /* CONFIG_PERF_EVENTS */
1483
1484 /*
1485 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1486 *
1487 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1488 * lockless, but we can't race with this __init function.
1489 */
1490 static int kprobe_register(struct trace_event_call *event,
1491 enum trace_reg type, void *data)
1492 {
1493 struct trace_event_file *file = data;
1494
1495 switch (type) {
1496 case TRACE_REG_REGISTER:
1497 return enable_trace_kprobe(event, file);
1498 case TRACE_REG_UNREGISTER:
1499 return disable_trace_kprobe(event, file);
1500
1501 #ifdef CONFIG_PERF_EVENTS
1502 case TRACE_REG_PERF_REGISTER:
1503 return enable_trace_kprobe(event, NULL);
1504 case TRACE_REG_PERF_UNREGISTER:
1505 return disable_trace_kprobe(event, NULL);
1506 case TRACE_REG_PERF_OPEN:
1507 case TRACE_REG_PERF_CLOSE:
1508 case TRACE_REG_PERF_ADD:
1509 case TRACE_REG_PERF_DEL:
1510 return 0;
1511 #endif
1512 }
1513 return 0;
1514 }
1515
1516 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1517 {
1518 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1519 int ret = 0;
1520
1521 raw_cpu_inc(*tk->nhit);
1522
1523 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1524 kprobe_trace_func(tk, regs);
1525 #ifdef CONFIG_PERF_EVENTS
1526 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1527 ret = kprobe_perf_func(tk, regs);
1528 #endif
1529 return ret;
1530 }
1531 NOKPROBE_SYMBOL(kprobe_dispatcher);
1532
1533 static int
1534 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1535 {
1536 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1537
1538 raw_cpu_inc(*tk->nhit);
1539
1540 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1541 kretprobe_trace_func(tk, ri, regs);
1542 #ifdef CONFIG_PERF_EVENTS
1543 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1544 kretprobe_perf_func(tk, ri, regs);
1545 #endif
1546 return 0; /* We don't tweek kernel, so just return 0 */
1547 }
1548 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1549
1550 static struct trace_event_functions kretprobe_funcs = {
1551 .trace = print_kretprobe_event
1552 };
1553
1554 static struct trace_event_functions kprobe_funcs = {
1555 .trace = print_kprobe_event
1556 };
1557
1558 static inline void init_trace_event_call(struct trace_kprobe *tk)
1559 {
1560 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1561
1562 if (trace_kprobe_is_return(tk)) {
1563 call->event.funcs = &kretprobe_funcs;
1564 call->class->define_fields = kretprobe_event_define_fields;
1565 } else {
1566 call->event.funcs = &kprobe_funcs;
1567 call->class->define_fields = kprobe_event_define_fields;
1568 }
1569
1570 call->flags = TRACE_EVENT_FL_KPROBE;
1571 call->class->reg = kprobe_register;
1572 }
1573
1574 static int register_kprobe_event(struct trace_kprobe *tk)
1575 {
1576 init_trace_event_call(tk);
1577
1578 return trace_probe_register_event_call(&tk->tp);
1579 }
1580
1581 static int unregister_kprobe_event(struct trace_kprobe *tk)
1582 {
1583 return trace_probe_unregister_event_call(&tk->tp);
1584 }
1585
1586 #ifdef CONFIG_PERF_EVENTS
1587 /* create a trace_kprobe, but don't add it to global lists */
1588 struct trace_event_call *
1589 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1590 bool is_return)
1591 {
1592 struct trace_kprobe *tk;
1593 int ret;
1594 char *event;
1595
1596 /*
1597 * local trace_kprobes are not added to dyn_event, so they are never
1598 * searched in find_trace_kprobe(). Therefore, there is no concern of
1599 * duplicated name here.
1600 */
1601 event = func ? func : "DUMMY_EVENT";
1602
1603 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1604 offs, 0 /* maxactive */, 0 /* nargs */,
1605 is_return);
1606
1607 if (IS_ERR(tk)) {
1608 pr_info("Failed to allocate trace_probe.(%d)\n",
1609 (int)PTR_ERR(tk));
1610 return ERR_CAST(tk);
1611 }
1612
1613 init_trace_event_call(tk);
1614
1615 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1616 ret = -ENOMEM;
1617 goto error;
1618 }
1619
1620 ret = __register_trace_kprobe(tk);
1621 if (ret < 0)
1622 goto error;
1623
1624 return trace_probe_event_call(&tk->tp);
1625 error:
1626 free_trace_kprobe(tk);
1627 return ERR_PTR(ret);
1628 }
1629
1630 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1631 {
1632 struct trace_kprobe *tk;
1633
1634 tk = trace_kprobe_primary_from_call(event_call);
1635 if (unlikely(!tk))
1636 return;
1637
1638 if (trace_probe_is_enabled(&tk->tp)) {
1639 WARN_ON(1);
1640 return;
1641 }
1642
1643 __unregister_trace_kprobe(tk);
1644
1645 free_trace_kprobe(tk);
1646 }
1647 #endif /* CONFIG_PERF_EVENTS */
1648
1649 static __init void enable_boot_kprobe_events(void)
1650 {
1651 struct trace_array *tr = top_trace_array();
1652 struct trace_event_file *file;
1653 struct trace_kprobe *tk;
1654 struct dyn_event *pos;
1655
1656 mutex_lock(&event_mutex);
1657 for_each_trace_kprobe(tk, pos) {
1658 list_for_each_entry(file, &tr->events, list)
1659 if (file->event_call == trace_probe_event_call(&tk->tp))
1660 trace_event_enable_disable(file, 1, 0);
1661 }
1662 mutex_unlock(&event_mutex);
1663 }
1664
1665 static __init void setup_boot_kprobe_events(void)
1666 {
1667 char *p, *cmd = kprobe_boot_events_buf;
1668 int ret;
1669
1670 strreplace(kprobe_boot_events_buf, ',', ' ');
1671
1672 while (cmd && *cmd != '\0') {
1673 p = strchr(cmd, ';');
1674 if (p)
1675 *p++ = '\0';
1676
1677 ret = trace_run_command(cmd, create_or_delete_trace_kprobe);
1678 if (ret)
1679 pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1680 else
1681 kprobe_boot_events_enabled = true;
1682
1683 cmd = p;
1684 }
1685
1686 enable_boot_kprobe_events();
1687 }
1688
1689 /* Make a tracefs interface for controlling probe points */
1690 static __init int init_kprobe_trace(void)
1691 {
1692 struct dentry *d_tracer;
1693 struct dentry *entry;
1694 int ret;
1695
1696 ret = dyn_event_register(&trace_kprobe_ops);
1697 if (ret)
1698 return ret;
1699
1700 if (register_module_notifier(&trace_kprobe_module_nb))
1701 return -EINVAL;
1702
1703 d_tracer = tracing_init_dentry();
1704 if (IS_ERR(d_tracer))
1705 return 0;
1706
1707 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1708 NULL, &kprobe_events_ops);
1709
1710 /* Event list interface */
1711 if (!entry)
1712 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1713
1714 /* Profile interface */
1715 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1716 NULL, &kprobe_profile_ops);
1717
1718 if (!entry)
1719 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1720
1721 setup_boot_kprobe_events();
1722
1723 return 0;
1724 }
1725 fs_initcall(init_kprobe_trace);
1726
1727
1728 #ifdef CONFIG_FTRACE_STARTUP_TEST
1729 static __init struct trace_event_file *
1730 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1731 {
1732 struct trace_event_file *file;
1733
1734 list_for_each_entry(file, &tr->events, list)
1735 if (file->event_call == trace_probe_event_call(&tk->tp))
1736 return file;
1737
1738 return NULL;
1739 }
1740
1741 /*
1742 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1743 * stage, we can do this lockless.
1744 */
1745 static __init int kprobe_trace_self_tests_init(void)
1746 {
1747 int ret, warn = 0;
1748 int (*target)(int, int, int, int, int, int);
1749 struct trace_kprobe *tk;
1750 struct trace_event_file *file;
1751
1752 if (tracing_is_disabled())
1753 return -ENODEV;
1754
1755 if (kprobe_boot_events_enabled) {
1756 pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n");
1757 return 0;
1758 }
1759
1760 target = kprobe_trace_selftest_target;
1761
1762 pr_info("Testing kprobe tracing: ");
1763
1764 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
1765 create_or_delete_trace_kprobe);
1766 if (WARN_ON_ONCE(ret)) {
1767 pr_warn("error on probing function entry.\n");
1768 warn++;
1769 } else {
1770 /* Enable trace point */
1771 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1772 if (WARN_ON_ONCE(tk == NULL)) {
1773 pr_warn("error on getting new probe.\n");
1774 warn++;
1775 } else {
1776 file = find_trace_probe_file(tk, top_trace_array());
1777 if (WARN_ON_ONCE(file == NULL)) {
1778 pr_warn("error on getting probe file.\n");
1779 warn++;
1780 } else
1781 enable_trace_kprobe(
1782 trace_probe_event_call(&tk->tp), file);
1783 }
1784 }
1785
1786 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
1787 create_or_delete_trace_kprobe);
1788 if (WARN_ON_ONCE(ret)) {
1789 pr_warn("error on probing function return.\n");
1790 warn++;
1791 } else {
1792 /* Enable trace point */
1793 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1794 if (WARN_ON_ONCE(tk == NULL)) {
1795 pr_warn("error on getting 2nd new probe.\n");
1796 warn++;
1797 } else {
1798 file = find_trace_probe_file(tk, top_trace_array());
1799 if (WARN_ON_ONCE(file == NULL)) {
1800 pr_warn("error on getting probe file.\n");
1801 warn++;
1802 } else
1803 enable_trace_kprobe(
1804 trace_probe_event_call(&tk->tp), file);
1805 }
1806 }
1807
1808 if (warn)
1809 goto end;
1810
1811 ret = target(1, 2, 3, 4, 5, 6);
1812
1813 /*
1814 * Not expecting an error here, the check is only to prevent the
1815 * optimizer from removing the call to target() as otherwise there
1816 * are no side-effects and the call is never performed.
1817 */
1818 if (ret != 21)
1819 warn++;
1820
1821 /* Disable trace points before removing it */
1822 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1823 if (WARN_ON_ONCE(tk == NULL)) {
1824 pr_warn("error on getting test probe.\n");
1825 warn++;
1826 } else {
1827 if (trace_kprobe_nhit(tk) != 1) {
1828 pr_warn("incorrect number of testprobe hits\n");
1829 warn++;
1830 }
1831
1832 file = find_trace_probe_file(tk, top_trace_array());
1833 if (WARN_ON_ONCE(file == NULL)) {
1834 pr_warn("error on getting probe file.\n");
1835 warn++;
1836 } else
1837 disable_trace_kprobe(
1838 trace_probe_event_call(&tk->tp), file);
1839 }
1840
1841 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1842 if (WARN_ON_ONCE(tk == NULL)) {
1843 pr_warn("error on getting 2nd test probe.\n");
1844 warn++;
1845 } else {
1846 if (trace_kprobe_nhit(tk) != 1) {
1847 pr_warn("incorrect number of testprobe2 hits\n");
1848 warn++;
1849 }
1850
1851 file = find_trace_probe_file(tk, top_trace_array());
1852 if (WARN_ON_ONCE(file == NULL)) {
1853 pr_warn("error on getting probe file.\n");
1854 warn++;
1855 } else
1856 disable_trace_kprobe(
1857 trace_probe_event_call(&tk->tp), file);
1858 }
1859
1860 ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
1861 if (WARN_ON_ONCE(ret)) {
1862 pr_warn("error on deleting a probe.\n");
1863 warn++;
1864 }
1865
1866 ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
1867 if (WARN_ON_ONCE(ret)) {
1868 pr_warn("error on deleting a probe.\n");
1869 warn++;
1870 }
1871
1872 end:
1873 ret = dyn_events_release_all(&trace_kprobe_ops);
1874 if (WARN_ON_ONCE(ret)) {
1875 pr_warn("error on cleaning up probes.\n");
1876 warn++;
1877 }
1878 /*
1879 * Wait for the optimizer work to finish. Otherwise it might fiddle
1880 * with probes in already freed __init text.
1881 */
1882 wait_for_kprobe_optimizer();
1883 if (warn)
1884 pr_cont("NG: Some tests are failed. Please check them.\n");
1885 else
1886 pr_cont("OK\n");
1887 return 0;
1888 }
1889
1890 late_initcall(kprobe_trace_self_tests_init);
1891
1892 #endif
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