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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 */
28static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
29static bool kprobe_boot_events_enabled __initdata;
30
31static 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
38static int trace_kprobe_create(int argc, const char **argv);
39static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
40static int trace_kprobe_release(struct dyn_event *ev);
41static bool trace_kprobe_is_busy(struct dyn_event *ev);
42static bool trace_kprobe_match(const char *system, const char *event,
43 int argc, const char **argv, struct dyn_event *ev);
44
45static 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 */
56struct 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
64static bool is_trace_kprobe(struct dyn_event *ev)
65{
66 return ev->ops == &trace_kprobe_ops;
67}
68
69static 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
87static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
88{
89 return tk->rp.handler != NULL;
90}
91
92static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
93{
94 return tk->symbol ? tk->symbol : "unknown";
95}
96
97static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
98{
99 return tk->rp.kp.offset;
100}
101
102static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
103{
104 return !!(kprobe_gone(&tk->rp.kp));
105}
106
107static 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
115static 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
134static 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
141static 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
163static 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
173static 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
184static 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 */
191static nokprobe_inline
192unsigned 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
207static nokprobe_inline struct trace_kprobe *
208trace_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
219bool 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
228bool 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
236static int register_kprobe_event(struct trace_kprobe *tk);
237static int unregister_kprobe_event(struct trace_kprobe *tk);
238
239static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
240static int kretprobe_dispatcher(struct kretprobe_instance *ri,
241 struct pt_regs *regs);
242
243static 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 */
256static 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;
299error:
300 free_trace_kprobe(tk);
301 return ERR_PTR(ret);
302}
303
304static 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
317static 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
331static 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 */
351static 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 */
402static 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)
438static bool within_notrace_func(struct trace_kprobe *tk)
439{
440 unsigned long offset, size, addr;
441
442 addr = trace_kprobe_address(tk);
443 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
444 return false;
445
446 /* Get the entry address of the target function */
447 addr -= offset;
448
449 /*
450 * Since ftrace_location_range() does inclusive range check, we need
451 * to subtract 1 byte from the end address.
452 */
453 return !ftrace_location_range(addr, addr + size - 1);
454}
455#else
456#define within_notrace_func(tk) (false)
457#endif
458
459/* Internal register function - just handle k*probes and flags */
460static int __register_trace_kprobe(struct trace_kprobe *tk)
461{
462 int i, ret;
463
464 ret = security_locked_down(LOCKDOWN_KPROBES);
465 if (ret)
466 return ret;
467
468 if (trace_kprobe_is_registered(tk))
469 return -EINVAL;
470
471 if (within_notrace_func(tk)) {
472 pr_warn("Could not probe notrace function %s\n",
473 trace_kprobe_symbol(tk));
474 return -EINVAL;
475 }
476
477 for (i = 0; i < tk->tp.nr_args; i++) {
478 ret = traceprobe_update_arg(&tk->tp.args[i]);
479 if (ret)
480 return ret;
481 }
482
483 /* Set/clear disabled flag according to tp->flag */
484 if (trace_probe_is_enabled(&tk->tp))
485 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
486 else
487 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
488
489 if (trace_kprobe_is_return(tk))
490 ret = register_kretprobe(&tk->rp);
491 else
492 ret = register_kprobe(&tk->rp.kp);
493
494 return ret;
495}
496
497/* Internal unregister function - just handle k*probes and flags */
498static void __unregister_trace_kprobe(struct trace_kprobe *tk)
499{
500 if (trace_kprobe_is_registered(tk)) {
501 if (trace_kprobe_is_return(tk))
502 unregister_kretprobe(&tk->rp);
503 else
504 unregister_kprobe(&tk->rp.kp);
505 /* Cleanup kprobe for reuse and mark it unregistered */
506 INIT_HLIST_NODE(&tk->rp.kp.hlist);
507 INIT_LIST_HEAD(&tk->rp.kp.list);
508 if (tk->rp.kp.symbol_name)
509 tk->rp.kp.addr = NULL;
510 }
511}
512
513/* Unregister a trace_probe and probe_event */
514static int unregister_trace_kprobe(struct trace_kprobe *tk)
515{
516 /* If other probes are on the event, just unregister kprobe */
517 if (trace_probe_has_sibling(&tk->tp))
518 goto unreg;
519
520 /* Enabled event can not be unregistered */
521 if (trace_probe_is_enabled(&tk->tp))
522 return -EBUSY;
523
524 /* Will fail if probe is being used by ftrace or perf */
525 if (unregister_kprobe_event(tk))
526 return -EBUSY;
527
528unreg:
529 __unregister_trace_kprobe(tk);
530 dyn_event_remove(&tk->devent);
531 trace_probe_unlink(&tk->tp);
532
533 return 0;
534}
535
536static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
537 struct trace_kprobe *comp)
538{
539 struct trace_probe_event *tpe = orig->tp.event;
540 struct trace_probe *pos;
541 int i;
542
543 list_for_each_entry(pos, &tpe->probes, list) {
544 orig = container_of(pos, struct trace_kprobe, tp);
545 if (strcmp(trace_kprobe_symbol(orig),
546 trace_kprobe_symbol(comp)) ||
547 trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
548 continue;
549
550 /*
551 * trace_probe_compare_arg_type() ensured that nr_args and
552 * each argument name and type are same. Let's compare comm.
553 */
554 for (i = 0; i < orig->tp.nr_args; i++) {
555 if (strcmp(orig->tp.args[i].comm,
556 comp->tp.args[i].comm))
557 break;
558 }
559
560 if (i == orig->tp.nr_args)
561 return true;
562 }
563
564 return false;
565}
566
567static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
568{
569 int ret;
570
571 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
572 if (ret) {
573 /* Note that argument starts index = 2 */
574 trace_probe_log_set_index(ret + 1);
575 trace_probe_log_err(0, DIFF_ARG_TYPE);
576 return -EEXIST;
577 }
578 if (trace_kprobe_has_same_kprobe(to, tk)) {
579 trace_probe_log_set_index(0);
580 trace_probe_log_err(0, SAME_PROBE);
581 return -EEXIST;
582 }
583
584 /* Append to existing event */
585 ret = trace_probe_append(&tk->tp, &to->tp);
586 if (ret)
587 return ret;
588
589 /* Register k*probe */
590 ret = __register_trace_kprobe(tk);
591 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
592 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
593 ret = 0;
594 }
595
596 if (ret)
597 trace_probe_unlink(&tk->tp);
598 else
599 dyn_event_add(&tk->devent);
600
601 return ret;
602}
603
604/* Register a trace_probe and probe_event */
605static int register_trace_kprobe(struct trace_kprobe *tk)
606{
607 struct trace_kprobe *old_tk;
608 int ret;
609
610 mutex_lock(&event_mutex);
611
612 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
613 trace_probe_group_name(&tk->tp));
614 if (old_tk) {
615 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
616 trace_probe_log_set_index(0);
617 trace_probe_log_err(0, DIFF_PROBE_TYPE);
618 ret = -EEXIST;
619 } else {
620 ret = append_trace_kprobe(tk, old_tk);
621 }
622 goto end;
623 }
624
625 /* Register new event */
626 ret = register_kprobe_event(tk);
627 if (ret) {
628 pr_warn("Failed to register probe event(%d)\n", ret);
629 goto end;
630 }
631
632 /* Register k*probe */
633 ret = __register_trace_kprobe(tk);
634 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
635 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
636 ret = 0;
637 }
638
639 if (ret < 0)
640 unregister_kprobe_event(tk);
641 else
642 dyn_event_add(&tk->devent);
643
644end:
645 mutex_unlock(&event_mutex);
646 return ret;
647}
648
649/* Module notifier call back, checking event on the module */
650static int trace_kprobe_module_callback(struct notifier_block *nb,
651 unsigned long val, void *data)
652{
653 struct module *mod = data;
654 struct dyn_event *pos;
655 struct trace_kprobe *tk;
656 int ret;
657
658 if (val != MODULE_STATE_COMING)
659 return NOTIFY_DONE;
660
661 /* Update probes on coming module */
662 mutex_lock(&event_mutex);
663 for_each_trace_kprobe(tk, pos) {
664 if (trace_kprobe_within_module(tk, mod)) {
665 /* Don't need to check busy - this should have gone. */
666 __unregister_trace_kprobe(tk);
667 ret = __register_trace_kprobe(tk);
668 if (ret)
669 pr_warn("Failed to re-register probe %s on %s: %d\n",
670 trace_probe_name(&tk->tp),
671 mod->name, ret);
672 }
673 }
674 mutex_unlock(&event_mutex);
675
676 return NOTIFY_DONE;
677}
678
679static struct notifier_block trace_kprobe_module_nb = {
680 .notifier_call = trace_kprobe_module_callback,
681 .priority = 1 /* Invoked after kprobe module callback */
682};
683
684/* Convert certain expected symbols into '_' when generating event names */
685static inline void sanitize_event_name(char *name)
686{
687 while (*name++ != '\0')
688 if (*name == ':' || *name == '.')
689 *name = '_';
690}
691
692static int trace_kprobe_create(int argc, const char *argv[])
693{
694 /*
695 * Argument syntax:
696 * - Add kprobe:
697 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
698 * - Add kretprobe:
699 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
700 * Fetch args:
701 * $retval : fetch return value
702 * $stack : fetch stack address
703 * $stackN : fetch Nth of stack (N:0-)
704 * $comm : fetch current task comm
705 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
706 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
707 * %REG : fetch register REG
708 * Dereferencing memory fetch:
709 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
710 * Alias name of args:
711 * NAME=FETCHARG : set NAME as alias of FETCHARG.
712 * Type of args:
713 * FETCHARG:TYPE : use TYPE instead of unsigned long.
714 */
715 struct trace_kprobe *tk = NULL;
716 int i, len, ret = 0;
717 bool is_return = false;
718 char *symbol = NULL, *tmp = NULL;
719 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
720 int maxactive = 0;
721 long offset = 0;
722 void *addr = NULL;
723 char buf[MAX_EVENT_NAME_LEN];
724 unsigned int flags = TPARG_FL_KERNEL;
725
726 switch (argv[0][0]) {
727 case 'r':
728 is_return = true;
729 flags |= TPARG_FL_RETURN;
730 break;
731 case 'p':
732 break;
733 default:
734 return -ECANCELED;
735 }
736 if (argc < 2)
737 return -ECANCELED;
738
739 trace_probe_log_init("trace_kprobe", argc, argv);
740
741 event = strchr(&argv[0][1], ':');
742 if (event)
743 event++;
744
745 if (isdigit(argv[0][1])) {
746 if (!is_return) {
747 trace_probe_log_err(1, MAXACT_NO_KPROBE);
748 goto parse_error;
749 }
750 if (event)
751 len = event - &argv[0][1] - 1;
752 else
753 len = strlen(&argv[0][1]);
754 if (len > MAX_EVENT_NAME_LEN - 1) {
755 trace_probe_log_err(1, BAD_MAXACT);
756 goto parse_error;
757 }
758 memcpy(buf, &argv[0][1], len);
759 buf[len] = '\0';
760 ret = kstrtouint(buf, 0, &maxactive);
761 if (ret || !maxactive) {
762 trace_probe_log_err(1, BAD_MAXACT);
763 goto parse_error;
764 }
765 /* kretprobes instances are iterated over via a list. The
766 * maximum should stay reasonable.
767 */
768 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
769 trace_probe_log_err(1, MAXACT_TOO_BIG);
770 goto parse_error;
771 }
772 }
773
774 /* try to parse an address. if that fails, try to read the
775 * input as a symbol. */
776 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
777 trace_probe_log_set_index(1);
778 /* Check whether uprobe event specified */
779 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
780 ret = -ECANCELED;
781 goto error;
782 }
783 /* a symbol specified */
784 symbol = kstrdup(argv[1], GFP_KERNEL);
785 if (!symbol)
786 return -ENOMEM;
787 /* TODO: support .init module functions */
788 ret = traceprobe_split_symbol_offset(symbol, &offset);
789 if (ret || offset < 0 || offset > UINT_MAX) {
790 trace_probe_log_err(0, BAD_PROBE_ADDR);
791 goto parse_error;
792 }
793 if (kprobe_on_func_entry(NULL, symbol, offset))
794 flags |= TPARG_FL_FENTRY;
795 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
796 trace_probe_log_err(0, BAD_RETPROBE);
797 goto parse_error;
798 }
799 }
800
801 trace_probe_log_set_index(0);
802 if (event) {
803 ret = traceprobe_parse_event_name(&event, &group, buf,
804 event - argv[0]);
805 if (ret)
806 goto parse_error;
807 } else {
808 /* Make a new event name */
809 if (symbol)
810 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
811 is_return ? 'r' : 'p', symbol, offset);
812 else
813 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
814 is_return ? 'r' : 'p', addr);
815 sanitize_event_name(buf);
816 event = buf;
817 }
818
819 /* setup a probe */
820 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
821 argc - 2, is_return);
822 if (IS_ERR(tk)) {
823 ret = PTR_ERR(tk);
824 /* This must return -ENOMEM, else there is a bug */
825 WARN_ON_ONCE(ret != -ENOMEM);
826 goto out; /* We know tk is not allocated */
827 }
828 argc -= 2; argv += 2;
829
830 /* parse arguments */
831 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
832 tmp = kstrdup(argv[i], GFP_KERNEL);
833 if (!tmp) {
834 ret = -ENOMEM;
835 goto error;
836 }
837
838 trace_probe_log_set_index(i + 2);
839 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
840 kfree(tmp);
841 if (ret)
842 goto error; /* This can be -ENOMEM */
843 }
844
845 ret = traceprobe_set_print_fmt(&tk->tp, is_return);
846 if (ret < 0)
847 goto error;
848
849 ret = register_trace_kprobe(tk);
850 if (ret) {
851 trace_probe_log_set_index(1);
852 if (ret == -EILSEQ)
853 trace_probe_log_err(0, BAD_INSN_BNDRY);
854 else if (ret == -ENOENT)
855 trace_probe_log_err(0, BAD_PROBE_ADDR);
856 else if (ret != -ENOMEM && ret != -EEXIST)
857 trace_probe_log_err(0, FAIL_REG_PROBE);
858 goto error;
859 }
860
861out:
862 trace_probe_log_clear();
863 kfree(symbol);
864 return ret;
865
866parse_error:
867 ret = -EINVAL;
868error:
869 free_trace_kprobe(tk);
870 goto out;
871}
872
873static int create_or_delete_trace_kprobe(int argc, char **argv)
874{
875 int ret;
876
877 if (argv[0][0] == '-')
878 return dyn_event_release(argc, argv, &trace_kprobe_ops);
879
880 ret = trace_kprobe_create(argc, (const char **)argv);
881 return ret == -ECANCELED ? -EINVAL : ret;
882}
883
884static int trace_kprobe_release(struct dyn_event *ev)
885{
886 struct trace_kprobe *tk = to_trace_kprobe(ev);
887 int ret = unregister_trace_kprobe(tk);
888
889 if (!ret)
890 free_trace_kprobe(tk);
891 return ret;
892}
893
894static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
895{
896 struct trace_kprobe *tk = to_trace_kprobe(ev);
897 int i;
898
899 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
900 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
901 trace_probe_name(&tk->tp));
902
903 if (!tk->symbol)
904 seq_printf(m, " 0x%p", tk->rp.kp.addr);
905 else if (tk->rp.kp.offset)
906 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
907 tk->rp.kp.offset);
908 else
909 seq_printf(m, " %s", trace_kprobe_symbol(tk));
910
911 for (i = 0; i < tk->tp.nr_args; i++)
912 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
913 seq_putc(m, '\n');
914
915 return 0;
916}
917
918static int probes_seq_show(struct seq_file *m, void *v)
919{
920 struct dyn_event *ev = v;
921
922 if (!is_trace_kprobe(ev))
923 return 0;
924
925 return trace_kprobe_show(m, ev);
926}
927
928static const struct seq_operations probes_seq_op = {
929 .start = dyn_event_seq_start,
930 .next = dyn_event_seq_next,
931 .stop = dyn_event_seq_stop,
932 .show = probes_seq_show
933};
934
935static int probes_open(struct inode *inode, struct file *file)
936{
937 int ret;
938
939 ret = security_locked_down(LOCKDOWN_TRACEFS);
940 if (ret)
941 return ret;
942
943 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
944 ret = dyn_events_release_all(&trace_kprobe_ops);
945 if (ret < 0)
946 return ret;
947 }
948
949 return seq_open(file, &probes_seq_op);
950}
951
952static ssize_t probes_write(struct file *file, const char __user *buffer,
953 size_t count, loff_t *ppos)
954{
955 return trace_parse_run_command(file, buffer, count, ppos,
956 create_or_delete_trace_kprobe);
957}
958
959static const struct file_operations kprobe_events_ops = {
960 .owner = THIS_MODULE,
961 .open = probes_open,
962 .read = seq_read,
963 .llseek = seq_lseek,
964 .release = seq_release,
965 .write = probes_write,
966};
967
968/* Probes profiling interfaces */
969static int probes_profile_seq_show(struct seq_file *m, void *v)
970{
971 struct dyn_event *ev = v;
972 struct trace_kprobe *tk;
973
974 if (!is_trace_kprobe(ev))
975 return 0;
976
977 tk = to_trace_kprobe(ev);
978 seq_printf(m, " %-44s %15lu %15lu\n",
979 trace_probe_name(&tk->tp),
980 trace_kprobe_nhit(tk),
981 tk->rp.kp.nmissed);
982
983 return 0;
984}
985
986static const struct seq_operations profile_seq_op = {
987 .start = dyn_event_seq_start,
988 .next = dyn_event_seq_next,
989 .stop = dyn_event_seq_stop,
990 .show = probes_profile_seq_show
991};
992
993static int profile_open(struct inode *inode, struct file *file)
994{
995 int ret;
996
997 ret = security_locked_down(LOCKDOWN_TRACEFS);
998 if (ret)
999 return ret;
1000
1001 return seq_open(file, &profile_seq_op);
1002}
1003
1004static const struct file_operations kprobe_profile_ops = {
1005 .owner = THIS_MODULE,
1006 .open = profile_open,
1007 .read = seq_read,
1008 .llseek = seq_lseek,
1009 .release = seq_release,
1010};
1011
1012/* Kprobe specific fetch functions */
1013
1014/* Return the length of string -- including null terminal byte */
1015static nokprobe_inline int
1016fetch_store_strlen(unsigned long addr)
1017{
1018 int ret, len = 0;
1019 u8 c;
1020
1021 do {
1022 ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
1023 len++;
1024 } while (c && ret == 0 && len < MAX_STRING_SIZE);
1025
1026 return (ret < 0) ? ret : len;
1027}
1028
1029/* Return the length of string -- including null terminal byte */
1030static nokprobe_inline int
1031fetch_store_strlen_user(unsigned long addr)
1032{
1033 const void __user *uaddr = (__force const void __user *)addr;
1034
1035 return strnlen_unsafe_user(uaddr, MAX_STRING_SIZE);
1036}
1037
1038/*
1039 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
1040 * length and relative data location.
1041 */
1042static nokprobe_inline int
1043fetch_store_string(unsigned long addr, void *dest, void *base)
1044{
1045 int maxlen = get_loc_len(*(u32 *)dest);
1046 void *__dest;
1047 long ret;
1048
1049 if (unlikely(!maxlen))
1050 return -ENOMEM;
1051
1052 __dest = get_loc_data(dest, base);
1053
1054 /*
1055 * Try to get string again, since the string can be changed while
1056 * probing.
1057 */
1058 ret = strncpy_from_unsafe(__dest, (void *)addr, maxlen);
1059 if (ret >= 0)
1060 *(u32 *)dest = make_data_loc(ret, __dest - base);
1061
1062 return ret;
1063}
1064
1065/*
1066 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
1067 * with max length and relative data location.
1068 */
1069static nokprobe_inline int
1070fetch_store_string_user(unsigned long addr, void *dest, void *base)
1071{
1072 const void __user *uaddr = (__force const void __user *)addr;
1073 int maxlen = get_loc_len(*(u32 *)dest);
1074 void *__dest;
1075 long ret;
1076
1077 if (unlikely(!maxlen))
1078 return -ENOMEM;
1079
1080 __dest = get_loc_data(dest, base);
1081
1082 ret = strncpy_from_unsafe_user(__dest, uaddr, maxlen);
1083 if (ret >= 0)
1084 *(u32 *)dest = make_data_loc(ret, __dest - base);
1085
1086 return ret;
1087}
1088
1089static nokprobe_inline int
1090probe_mem_read(void *dest, void *src, size_t size)
1091{
1092 return probe_kernel_read(dest, src, size);
1093}
1094
1095static nokprobe_inline int
1096probe_mem_read_user(void *dest, void *src, size_t size)
1097{
1098 const void __user *uaddr = (__force const void __user *)src;
1099
1100 return probe_user_read(dest, uaddr, size);
1101}
1102
1103/* Note that we don't verify it, since the code does not come from user space */
1104static int
1105process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
1106 void *base)
1107{
1108 unsigned long val;
1109
1110retry:
1111 /* 1st stage: get value from context */
1112 switch (code->op) {
1113 case FETCH_OP_REG:
1114 val = regs_get_register(regs, code->param);
1115 break;
1116 case FETCH_OP_STACK:
1117 val = regs_get_kernel_stack_nth(regs, code->param);
1118 break;
1119 case FETCH_OP_STACKP:
1120 val = kernel_stack_pointer(regs);
1121 break;
1122 case FETCH_OP_RETVAL:
1123 val = regs_return_value(regs);
1124 break;
1125 case FETCH_OP_IMM:
1126 val = code->immediate;
1127 break;
1128 case FETCH_OP_COMM:
1129 val = (unsigned long)current->comm;
1130 break;
1131 case FETCH_OP_DATA:
1132 val = (unsigned long)code->data;
1133 break;
1134#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1135 case FETCH_OP_ARG:
1136 val = regs_get_kernel_argument(regs, code->param);
1137 break;
1138#endif
1139 case FETCH_NOP_SYMBOL: /* Ignore a place holder */
1140 code++;
1141 goto retry;
1142 default:
1143 return -EILSEQ;
1144 }
1145 code++;
1146
1147 return process_fetch_insn_bottom(code, val, dest, base);
1148}
1149NOKPROBE_SYMBOL(process_fetch_insn)
1150
1151/* Kprobe handler */
1152static nokprobe_inline void
1153__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1154 struct trace_event_file *trace_file)
1155{
1156 struct kprobe_trace_entry_head *entry;
1157 struct ring_buffer_event *event;
1158 struct ring_buffer *buffer;
1159 int size, dsize, pc;
1160 unsigned long irq_flags;
1161 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1162
1163 WARN_ON(call != trace_file->event_call);
1164
1165 if (trace_trigger_soft_disabled(trace_file))
1166 return;
1167
1168 local_save_flags(irq_flags);
1169 pc = preempt_count();
1170
1171 dsize = __get_data_size(&tk->tp, regs);
1172 size = sizeof(*entry) + tk->tp.size + dsize;
1173
1174 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1175 call->event.type,
1176 size, irq_flags, pc);
1177 if (!event)
1178 return;
1179
1180 entry = ring_buffer_event_data(event);
1181 entry->ip = (unsigned long)tk->rp.kp.addr;
1182 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1183
1184 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1185 entry, irq_flags, pc, regs);
1186}
1187
1188static void
1189kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1190{
1191 struct event_file_link *link;
1192
1193 trace_probe_for_each_link_rcu(link, &tk->tp)
1194 __kprobe_trace_func(tk, regs, link->file);
1195}
1196NOKPROBE_SYMBOL(kprobe_trace_func);
1197
1198/* Kretprobe handler */
1199static nokprobe_inline void
1200__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1201 struct pt_regs *regs,
1202 struct trace_event_file *trace_file)
1203{
1204 struct kretprobe_trace_entry_head *entry;
1205 struct ring_buffer_event *event;
1206 struct ring_buffer *buffer;
1207 int size, pc, dsize;
1208 unsigned long irq_flags;
1209 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1210
1211 WARN_ON(call != trace_file->event_call);
1212
1213 if (trace_trigger_soft_disabled(trace_file))
1214 return;
1215
1216 local_save_flags(irq_flags);
1217 pc = preempt_count();
1218
1219 dsize = __get_data_size(&tk->tp, regs);
1220 size = sizeof(*entry) + tk->tp.size + dsize;
1221
1222 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1223 call->event.type,
1224 size, irq_flags, pc);
1225 if (!event)
1226 return;
1227
1228 entry = ring_buffer_event_data(event);
1229 entry->func = (unsigned long)tk->rp.kp.addr;
1230 entry->ret_ip = (unsigned long)ri->ret_addr;
1231 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1232
1233 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1234 entry, irq_flags, pc, regs);
1235}
1236
1237static void
1238kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1239 struct pt_regs *regs)
1240{
1241 struct event_file_link *link;
1242
1243 trace_probe_for_each_link_rcu(link, &tk->tp)
1244 __kretprobe_trace_func(tk, ri, regs, link->file);
1245}
1246NOKPROBE_SYMBOL(kretprobe_trace_func);
1247
1248/* Event entry printers */
1249static enum print_line_t
1250print_kprobe_event(struct trace_iterator *iter, int flags,
1251 struct trace_event *event)
1252{
1253 struct kprobe_trace_entry_head *field;
1254 struct trace_seq *s = &iter->seq;
1255 struct trace_probe *tp;
1256
1257 field = (struct kprobe_trace_entry_head *)iter->ent;
1258 tp = trace_probe_primary_from_call(
1259 container_of(event, struct trace_event_call, event));
1260 if (WARN_ON_ONCE(!tp))
1261 goto out;
1262
1263 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1264
1265 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1266 goto out;
1267
1268 trace_seq_putc(s, ')');
1269
1270 if (print_probe_args(s, tp->args, tp->nr_args,
1271 (u8 *)&field[1], field) < 0)
1272 goto out;
1273
1274 trace_seq_putc(s, '\n');
1275 out:
1276 return trace_handle_return(s);
1277}
1278
1279static enum print_line_t
1280print_kretprobe_event(struct trace_iterator *iter, int flags,
1281 struct trace_event *event)
1282{
1283 struct kretprobe_trace_entry_head *field;
1284 struct trace_seq *s = &iter->seq;
1285 struct trace_probe *tp;
1286
1287 field = (struct kretprobe_trace_entry_head *)iter->ent;
1288 tp = trace_probe_primary_from_call(
1289 container_of(event, struct trace_event_call, event));
1290 if (WARN_ON_ONCE(!tp))
1291 goto out;
1292
1293 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1294
1295 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1296 goto out;
1297
1298 trace_seq_puts(s, " <- ");
1299
1300 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1301 goto out;
1302
1303 trace_seq_putc(s, ')');
1304
1305 if (print_probe_args(s, tp->args, tp->nr_args,
1306 (u8 *)&field[1], field) < 0)
1307 goto out;
1308
1309 trace_seq_putc(s, '\n');
1310
1311 out:
1312 return trace_handle_return(s);
1313}
1314
1315
1316static int kprobe_event_define_fields(struct trace_event_call *event_call)
1317{
1318 int ret;
1319 struct kprobe_trace_entry_head field;
1320 struct trace_probe *tp;
1321
1322 tp = trace_probe_primary_from_call(event_call);
1323 if (WARN_ON_ONCE(!tp))
1324 return -ENOENT;
1325
1326 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1327
1328 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1329}
1330
1331static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1332{
1333 int ret;
1334 struct kretprobe_trace_entry_head field;
1335 struct trace_probe *tp;
1336
1337 tp = trace_probe_primary_from_call(event_call);
1338 if (WARN_ON_ONCE(!tp))
1339 return -ENOENT;
1340
1341 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1342 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1343
1344 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1345}
1346
1347#ifdef CONFIG_PERF_EVENTS
1348
1349/* Kprobe profile handler */
1350static int
1351kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1352{
1353 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1354 struct kprobe_trace_entry_head *entry;
1355 struct hlist_head *head;
1356 int size, __size, dsize;
1357 int rctx;
1358
1359 if (bpf_prog_array_valid(call)) {
1360 unsigned long orig_ip = instruction_pointer(regs);
1361 int ret;
1362
1363 ret = trace_call_bpf(call, regs);
1364
1365 /*
1366 * We need to check and see if we modified the pc of the
1367 * pt_regs, and if so return 1 so that we don't do the
1368 * single stepping.
1369 */
1370 if (orig_ip != instruction_pointer(regs))
1371 return 1;
1372 if (!ret)
1373 return 0;
1374 }
1375
1376 head = this_cpu_ptr(call->perf_events);
1377 if (hlist_empty(head))
1378 return 0;
1379
1380 dsize = __get_data_size(&tk->tp, regs);
1381 __size = sizeof(*entry) + tk->tp.size + dsize;
1382 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1383 size -= sizeof(u32);
1384
1385 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1386 if (!entry)
1387 return 0;
1388
1389 entry->ip = (unsigned long)tk->rp.kp.addr;
1390 memset(&entry[1], 0, dsize);
1391 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1392 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1393 head, NULL);
1394 return 0;
1395}
1396NOKPROBE_SYMBOL(kprobe_perf_func);
1397
1398/* Kretprobe profile handler */
1399static void
1400kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1401 struct pt_regs *regs)
1402{
1403 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1404 struct kretprobe_trace_entry_head *entry;
1405 struct hlist_head *head;
1406 int size, __size, dsize;
1407 int rctx;
1408
1409 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1410 return;
1411
1412 head = this_cpu_ptr(call->perf_events);
1413 if (hlist_empty(head))
1414 return;
1415
1416 dsize = __get_data_size(&tk->tp, regs);
1417 __size = sizeof(*entry) + tk->tp.size + dsize;
1418 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1419 size -= sizeof(u32);
1420
1421 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1422 if (!entry)
1423 return;
1424
1425 entry->func = (unsigned long)tk->rp.kp.addr;
1426 entry->ret_ip = (unsigned long)ri->ret_addr;
1427 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1428 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1429 head, NULL);
1430}
1431NOKPROBE_SYMBOL(kretprobe_perf_func);
1432
1433int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1434 const char **symbol, u64 *probe_offset,
1435 u64 *probe_addr, bool perf_type_tracepoint)
1436{
1437 const char *pevent = trace_event_name(event->tp_event);
1438 const char *group = event->tp_event->class->system;
1439 struct trace_kprobe *tk;
1440
1441 if (perf_type_tracepoint)
1442 tk = find_trace_kprobe(pevent, group);
1443 else
1444 tk = event->tp_event->data;
1445 if (!tk)
1446 return -EINVAL;
1447
1448 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1449 : BPF_FD_TYPE_KPROBE;
1450 if (tk->symbol) {
1451 *symbol = tk->symbol;
1452 *probe_offset = tk->rp.kp.offset;
1453 *probe_addr = 0;
1454 } else {
1455 *symbol = NULL;
1456 *probe_offset = 0;
1457 *probe_addr = (unsigned long)tk->rp.kp.addr;
1458 }
1459 return 0;
1460}
1461#endif /* CONFIG_PERF_EVENTS */
1462
1463/*
1464 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1465 *
1466 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1467 * lockless, but we can't race with this __init function.
1468 */
1469static int kprobe_register(struct trace_event_call *event,
1470 enum trace_reg type, void *data)
1471{
1472 struct trace_event_file *file = data;
1473
1474 switch (type) {
1475 case TRACE_REG_REGISTER:
1476 return enable_trace_kprobe(event, file);
1477 case TRACE_REG_UNREGISTER:
1478 return disable_trace_kprobe(event, file);
1479
1480#ifdef CONFIG_PERF_EVENTS
1481 case TRACE_REG_PERF_REGISTER:
1482 return enable_trace_kprobe(event, NULL);
1483 case TRACE_REG_PERF_UNREGISTER:
1484 return disable_trace_kprobe(event, NULL);
1485 case TRACE_REG_PERF_OPEN:
1486 case TRACE_REG_PERF_CLOSE:
1487 case TRACE_REG_PERF_ADD:
1488 case TRACE_REG_PERF_DEL:
1489 return 0;
1490#endif
1491 }
1492 return 0;
1493}
1494
1495static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1496{
1497 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1498 int ret = 0;
1499
1500 raw_cpu_inc(*tk->nhit);
1501
1502 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1503 kprobe_trace_func(tk, regs);
1504#ifdef CONFIG_PERF_EVENTS
1505 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1506 ret = kprobe_perf_func(tk, regs);
1507#endif
1508 return ret;
1509}
1510NOKPROBE_SYMBOL(kprobe_dispatcher);
1511
1512static int
1513kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1514{
1515 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1516
1517 raw_cpu_inc(*tk->nhit);
1518
1519 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1520 kretprobe_trace_func(tk, ri, regs);
1521#ifdef CONFIG_PERF_EVENTS
1522 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1523 kretprobe_perf_func(tk, ri, regs);
1524#endif
1525 return 0; /* We don't tweek kernel, so just return 0 */
1526}
1527NOKPROBE_SYMBOL(kretprobe_dispatcher);
1528
1529static struct trace_event_functions kretprobe_funcs = {
1530 .trace = print_kretprobe_event
1531};
1532
1533static struct trace_event_functions kprobe_funcs = {
1534 .trace = print_kprobe_event
1535};
1536
1537static inline void init_trace_event_call(struct trace_kprobe *tk)
1538{
1539 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1540
1541 if (trace_kprobe_is_return(tk)) {
1542 call->event.funcs = &kretprobe_funcs;
1543 call->class->define_fields = kretprobe_event_define_fields;
1544 } else {
1545 call->event.funcs = &kprobe_funcs;
1546 call->class->define_fields = kprobe_event_define_fields;
1547 }
1548
1549 call->flags = TRACE_EVENT_FL_KPROBE;
1550 call->class->reg = kprobe_register;
1551}
1552
1553static int register_kprobe_event(struct trace_kprobe *tk)
1554{
1555 init_trace_event_call(tk);
1556
1557 return trace_probe_register_event_call(&tk->tp);
1558}
1559
1560static int unregister_kprobe_event(struct trace_kprobe *tk)
1561{
1562 return trace_probe_unregister_event_call(&tk->tp);
1563}
1564
1565#ifdef CONFIG_PERF_EVENTS
1566/* create a trace_kprobe, but don't add it to global lists */
1567struct trace_event_call *
1568create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1569 bool is_return)
1570{
1571 struct trace_kprobe *tk;
1572 int ret;
1573 char *event;
1574
1575 /*
1576 * local trace_kprobes are not added to dyn_event, so they are never
1577 * searched in find_trace_kprobe(). Therefore, there is no concern of
1578 * duplicated name here.
1579 */
1580 event = func ? func : "DUMMY_EVENT";
1581
1582 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1583 offs, 0 /* maxactive */, 0 /* nargs */,
1584 is_return);
1585
1586 if (IS_ERR(tk)) {
1587 pr_info("Failed to allocate trace_probe.(%d)\n",
1588 (int)PTR_ERR(tk));
1589 return ERR_CAST(tk);
1590 }
1591
1592 init_trace_event_call(tk);
1593
1594 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1595 ret = -ENOMEM;
1596 goto error;
1597 }
1598
1599 ret = __register_trace_kprobe(tk);
1600 if (ret < 0)
1601 goto error;
1602
1603 return trace_probe_event_call(&tk->tp);
1604error:
1605 free_trace_kprobe(tk);
1606 return ERR_PTR(ret);
1607}
1608
1609void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1610{
1611 struct trace_kprobe *tk;
1612
1613 tk = trace_kprobe_primary_from_call(event_call);
1614 if (unlikely(!tk))
1615 return;
1616
1617 if (trace_probe_is_enabled(&tk->tp)) {
1618 WARN_ON(1);
1619 return;
1620 }
1621
1622 __unregister_trace_kprobe(tk);
1623
1624 free_trace_kprobe(tk);
1625}
1626#endif /* CONFIG_PERF_EVENTS */
1627
1628static __init void enable_boot_kprobe_events(void)
1629{
1630 struct trace_array *tr = top_trace_array();
1631 struct trace_event_file *file;
1632 struct trace_kprobe *tk;
1633 struct dyn_event *pos;
1634
1635 mutex_lock(&event_mutex);
1636 for_each_trace_kprobe(tk, pos) {
1637 list_for_each_entry(file, &tr->events, list)
1638 if (file->event_call == trace_probe_event_call(&tk->tp))
1639 trace_event_enable_disable(file, 1, 0);
1640 }
1641 mutex_unlock(&event_mutex);
1642}
1643
1644static __init void setup_boot_kprobe_events(void)
1645{
1646 char *p, *cmd = kprobe_boot_events_buf;
1647 int ret;
1648
1649 strreplace(kprobe_boot_events_buf, ',', ' ');
1650
1651 while (cmd && *cmd != '\0') {
1652 p = strchr(cmd, ';');
1653 if (p)
1654 *p++ = '\0';
1655
1656 ret = trace_run_command(cmd, create_or_delete_trace_kprobe);
1657 if (ret)
1658 pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1659 else
1660 kprobe_boot_events_enabled = true;
1661
1662 cmd = p;
1663 }
1664
1665 enable_boot_kprobe_events();
1666}
1667
1668/* Make a tracefs interface for controlling probe points */
1669static __init int init_kprobe_trace(void)
1670{
1671 struct dentry *d_tracer;
1672 struct dentry *entry;
1673 int ret;
1674
1675 ret = dyn_event_register(&trace_kprobe_ops);
1676 if (ret)
1677 return ret;
1678
1679 if (register_module_notifier(&trace_kprobe_module_nb))
1680 return -EINVAL;
1681
1682 d_tracer = tracing_init_dentry();
1683 if (IS_ERR(d_tracer))
1684 return 0;
1685
1686 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1687 NULL, &kprobe_events_ops);
1688
1689 /* Event list interface */
1690 if (!entry)
1691 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1692
1693 /* Profile interface */
1694 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1695 NULL, &kprobe_profile_ops);
1696
1697 if (!entry)
1698 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1699
1700 setup_boot_kprobe_events();
1701
1702 return 0;
1703}
1704fs_initcall(init_kprobe_trace);
1705
1706
1707#ifdef CONFIG_FTRACE_STARTUP_TEST
1708static __init struct trace_event_file *
1709find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1710{
1711 struct trace_event_file *file;
1712
1713 list_for_each_entry(file, &tr->events, list)
1714 if (file->event_call == trace_probe_event_call(&tk->tp))
1715 return file;
1716
1717 return NULL;
1718}
1719
1720/*
1721 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1722 * stage, we can do this lockless.
1723 */
1724static __init int kprobe_trace_self_tests_init(void)
1725{
1726 int ret, warn = 0;
1727 int (*target)(int, int, int, int, int, int);
1728 struct trace_kprobe *tk;
1729 struct trace_event_file *file;
1730
1731 if (tracing_is_disabled())
1732 return -ENODEV;
1733
1734 if (kprobe_boot_events_enabled) {
1735 pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n");
1736 return 0;
1737 }
1738
1739 target = kprobe_trace_selftest_target;
1740
1741 pr_info("Testing kprobe tracing: ");
1742
1743 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
1744 create_or_delete_trace_kprobe);
1745 if (WARN_ON_ONCE(ret)) {
1746 pr_warn("error on probing function entry.\n");
1747 warn++;
1748 } else {
1749 /* Enable trace point */
1750 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1751 if (WARN_ON_ONCE(tk == NULL)) {
1752 pr_warn("error on getting new probe.\n");
1753 warn++;
1754 } else {
1755 file = find_trace_probe_file(tk, top_trace_array());
1756 if (WARN_ON_ONCE(file == NULL)) {
1757 pr_warn("error on getting probe file.\n");
1758 warn++;
1759 } else
1760 enable_trace_kprobe(
1761 trace_probe_event_call(&tk->tp), file);
1762 }
1763 }
1764
1765 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
1766 create_or_delete_trace_kprobe);
1767 if (WARN_ON_ONCE(ret)) {
1768 pr_warn("error on probing function return.\n");
1769 warn++;
1770 } else {
1771 /* Enable trace point */
1772 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1773 if (WARN_ON_ONCE(tk == NULL)) {
1774 pr_warn("error on getting 2nd new probe.\n");
1775 warn++;
1776 } else {
1777 file = find_trace_probe_file(tk, top_trace_array());
1778 if (WARN_ON_ONCE(file == NULL)) {
1779 pr_warn("error on getting probe file.\n");
1780 warn++;
1781 } else
1782 enable_trace_kprobe(
1783 trace_probe_event_call(&tk->tp), file);
1784 }
1785 }
1786
1787 if (warn)
1788 goto end;
1789
1790 ret = target(1, 2, 3, 4, 5, 6);
1791
1792 /*
1793 * Not expecting an error here, the check is only to prevent the
1794 * optimizer from removing the call to target() as otherwise there
1795 * are no side-effects and the call is never performed.
1796 */
1797 if (ret != 21)
1798 warn++;
1799
1800 /* Disable trace points before removing it */
1801 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1802 if (WARN_ON_ONCE(tk == NULL)) {
1803 pr_warn("error on getting test probe.\n");
1804 warn++;
1805 } else {
1806 if (trace_kprobe_nhit(tk) != 1) {
1807 pr_warn("incorrect number of testprobe hits\n");
1808 warn++;
1809 }
1810
1811 file = find_trace_probe_file(tk, top_trace_array());
1812 if (WARN_ON_ONCE(file == NULL)) {
1813 pr_warn("error on getting probe file.\n");
1814 warn++;
1815 } else
1816 disable_trace_kprobe(
1817 trace_probe_event_call(&tk->tp), file);
1818 }
1819
1820 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1821 if (WARN_ON_ONCE(tk == NULL)) {
1822 pr_warn("error on getting 2nd test probe.\n");
1823 warn++;
1824 } else {
1825 if (trace_kprobe_nhit(tk) != 1) {
1826 pr_warn("incorrect number of testprobe2 hits\n");
1827 warn++;
1828 }
1829
1830 file = find_trace_probe_file(tk, top_trace_array());
1831 if (WARN_ON_ONCE(file == NULL)) {
1832 pr_warn("error on getting probe file.\n");
1833 warn++;
1834 } else
1835 disable_trace_kprobe(
1836 trace_probe_event_call(&tk->tp), file);
1837 }
1838
1839 ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
1840 if (WARN_ON_ONCE(ret)) {
1841 pr_warn("error on deleting a probe.\n");
1842 warn++;
1843 }
1844
1845 ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
1846 if (WARN_ON_ONCE(ret)) {
1847 pr_warn("error on deleting a probe.\n");
1848 warn++;
1849 }
1850
1851end:
1852 ret = dyn_events_release_all(&trace_kprobe_ops);
1853 if (WARN_ON_ONCE(ret)) {
1854 pr_warn("error on cleaning up probes.\n");
1855 warn++;
1856 }
1857 /*
1858 * Wait for the optimizer work to finish. Otherwise it might fiddle
1859 * with probes in already freed __init text.
1860 */
1861 wait_for_kprobe_optimizer();
1862 if (warn)
1863 pr_cont("NG: Some tests are failed. Please check them.\n");
1864 else
1865 pr_cont("OK\n");
1866 return 0;
1867}
1868
1869late_initcall(kprobe_trace_self_tests_init);
1870
1871#endif
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/bpf-cgroup.h>
11#include <linux/security.h>
12#include <linux/module.h>
13#include <linux/uaccess.h>
14#include <linux/rculist.h>
15#include <linux/error-injection.h>
16
17#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
18
19#include "trace_dynevent.h"
20#include "trace_kprobe_selftest.h"
21#include "trace_probe.h"
22#include "trace_probe_tmpl.h"
23#include "trace_probe_kernel.h"
24
25#define KPROBE_EVENT_SYSTEM "kprobes"
26#define KRETPROBE_MAXACTIVE_MAX 4096
27
28/* Kprobe early definition from command line */
29static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
30
31static int __init set_kprobe_boot_events(char *str)
32{
33 strscpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
34 disable_tracing_selftest("running kprobe events");
35
36 return 1;
37}
38__setup("kprobe_event=", set_kprobe_boot_events);
39
40static int trace_kprobe_create(const char *raw_command);
41static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
42static int trace_kprobe_release(struct dyn_event *ev);
43static bool trace_kprobe_is_busy(struct dyn_event *ev);
44static bool trace_kprobe_match(const char *system, const char *event,
45 int argc, const char **argv, struct dyn_event *ev);
46
47static struct dyn_event_operations trace_kprobe_ops = {
48 .create = trace_kprobe_create,
49 .show = trace_kprobe_show,
50 .is_busy = trace_kprobe_is_busy,
51 .free = trace_kprobe_release,
52 .match = trace_kprobe_match,
53};
54
55/*
56 * Kprobe event core functions
57 */
58struct trace_kprobe {
59 struct dyn_event devent;
60 struct kretprobe rp; /* Use rp.kp for kprobe use */
61 unsigned long __percpu *nhit;
62 const char *symbol; /* symbol name */
63 struct trace_probe tp;
64};
65
66static bool is_trace_kprobe(struct dyn_event *ev)
67{
68 return ev->ops == &trace_kprobe_ops;
69}
70
71static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
72{
73 return container_of(ev, struct trace_kprobe, devent);
74}
75
76/**
77 * for_each_trace_kprobe - iterate over the trace_kprobe list
78 * @pos: the struct trace_kprobe * for each entry
79 * @dpos: the struct dyn_event * to use as a loop cursor
80 */
81#define for_each_trace_kprobe(pos, dpos) \
82 for_each_dyn_event(dpos) \
83 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
84
85static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
86{
87 return tk->rp.handler != NULL;
88}
89
90static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
91{
92 return tk->symbol ? tk->symbol : "unknown";
93}
94
95static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
96{
97 return tk->rp.kp.offset;
98}
99
100static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
101{
102 return kprobe_gone(&tk->rp.kp);
103}
104
105static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
106 struct module *mod)
107{
108 int len = strlen(module_name(mod));
109 const char *name = trace_kprobe_symbol(tk);
110
111 return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
112}
113
114static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
115{
116 char *p;
117 bool ret;
118
119 if (!tk->symbol)
120 return false;
121 p = strchr(tk->symbol, ':');
122 if (!p)
123 return true;
124 *p = '\0';
125 rcu_read_lock_sched();
126 ret = !!find_module(tk->symbol);
127 rcu_read_unlock_sched();
128 *p = ':';
129
130 return ret;
131}
132
133static bool trace_kprobe_is_busy(struct dyn_event *ev)
134{
135 struct trace_kprobe *tk = to_trace_kprobe(ev);
136
137 return trace_probe_is_enabled(&tk->tp);
138}
139
140static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
141 int argc, const char **argv)
142{
143 char buf[MAX_ARGSTR_LEN + 1];
144
145 if (!argc)
146 return true;
147
148 if (!tk->symbol)
149 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
150 else if (tk->rp.kp.offset)
151 snprintf(buf, sizeof(buf), "%s+%u",
152 trace_kprobe_symbol(tk), tk->rp.kp.offset);
153 else
154 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
155 if (strcmp(buf, argv[0]))
156 return false;
157 argc--; argv++;
158
159 return trace_probe_match_command_args(&tk->tp, argc, argv);
160}
161
162static bool trace_kprobe_match(const char *system, const char *event,
163 int argc, const char **argv, struct dyn_event *ev)
164{
165 struct trace_kprobe *tk = to_trace_kprobe(ev);
166
167 return (event[0] == '\0' ||
168 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
173static 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
184static 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 */
191static nokprobe_inline
192unsigned 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
207static nokprobe_inline struct trace_kprobe *
208trace_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
219bool 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) == 0) : false;
226}
227
228bool 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
236static int register_kprobe_event(struct trace_kprobe *tk);
237static int unregister_kprobe_event(struct trace_kprobe *tk);
238
239static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
240static int kretprobe_dispatcher(struct kretprobe_instance *ri,
241 struct pt_regs *regs);
242
243static 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 */
256static 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(struct_size(tk, tp.args, 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, false, nargs);
294 if (ret < 0)
295 goto error;
296
297 dyn_event_init(&tk->devent, &trace_kprobe_ops);
298 return tk;
299error:
300 free_trace_kprobe(tk);
301 return ERR_PTR(ret);
302}
303
304static 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
317static 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
331static void __disable_trace_kprobe(struct trace_probe *tp)
332{
333 struct trace_kprobe *tk;
334
335 list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
336 if (!trace_kprobe_is_registered(tk))
337 continue;
338 if (trace_kprobe_is_return(tk))
339 disable_kretprobe(&tk->rp);
340 else
341 disable_kprobe(&tk->rp.kp);
342 }
343}
344
345/*
346 * Enable trace_probe
347 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
348 */
349static int enable_trace_kprobe(struct trace_event_call *call,
350 struct trace_event_file *file)
351{
352 struct trace_probe *tp;
353 struct trace_kprobe *tk;
354 bool enabled;
355 int ret = 0;
356
357 tp = trace_probe_primary_from_call(call);
358 if (WARN_ON_ONCE(!tp))
359 return -ENODEV;
360 enabled = trace_probe_is_enabled(tp);
361
362 /* This also changes "enabled" state */
363 if (file) {
364 ret = trace_probe_add_file(tp, file);
365 if (ret)
366 return ret;
367 } else
368 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
369
370 if (enabled)
371 return 0;
372
373 list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
374 if (trace_kprobe_has_gone(tk))
375 continue;
376 ret = __enable_trace_kprobe(tk);
377 if (ret)
378 break;
379 enabled = true;
380 }
381
382 if (ret) {
383 /* Failed to enable one of them. Roll back all */
384 if (enabled)
385 __disable_trace_kprobe(tp);
386 if (file)
387 trace_probe_remove_file(tp, file);
388 else
389 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
390 }
391
392 return ret;
393}
394
395/*
396 * Disable trace_probe
397 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
398 */
399static int disable_trace_kprobe(struct trace_event_call *call,
400 struct trace_event_file *file)
401{
402 struct trace_probe *tp;
403
404 tp = trace_probe_primary_from_call(call);
405 if (WARN_ON_ONCE(!tp))
406 return -ENODEV;
407
408 if (file) {
409 if (!trace_probe_get_file_link(tp, file))
410 return -ENOENT;
411 if (!trace_probe_has_single_file(tp))
412 goto out;
413 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
414 } else
415 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
416
417 if (!trace_probe_is_enabled(tp))
418 __disable_trace_kprobe(tp);
419
420 out:
421 if (file)
422 /*
423 * Synchronization is done in below function. For perf event,
424 * file == NULL and perf_trace_event_unreg() calls
425 * tracepoint_synchronize_unregister() to ensure synchronize
426 * event. We don't need to care about it.
427 */
428 trace_probe_remove_file(tp, file);
429
430 return 0;
431}
432
433#if defined(CONFIG_DYNAMIC_FTRACE) && \
434 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
435static bool __within_notrace_func(unsigned long addr)
436{
437 unsigned long offset, size;
438
439 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
440 return false;
441
442 /* Get the entry address of the target function */
443 addr -= offset;
444
445 /*
446 * Since ftrace_location_range() does inclusive range check, we need
447 * to subtract 1 byte from the end address.
448 */
449 return !ftrace_location_range(addr, addr + size - 1);
450}
451
452static bool within_notrace_func(struct trace_kprobe *tk)
453{
454 unsigned long addr = trace_kprobe_address(tk);
455 char symname[KSYM_NAME_LEN], *p;
456
457 if (!__within_notrace_func(addr))
458 return false;
459
460 /* Check if the address is on a suffixed-symbol */
461 if (!lookup_symbol_name(addr, symname)) {
462 p = strchr(symname, '.');
463 if (!p)
464 return true;
465 *p = '\0';
466 addr = (unsigned long)kprobe_lookup_name(symname, 0);
467 if (addr)
468 return __within_notrace_func(addr);
469 }
470
471 return true;
472}
473#else
474#define within_notrace_func(tk) (false)
475#endif
476
477/* Internal register function - just handle k*probes and flags */
478static int __register_trace_kprobe(struct trace_kprobe *tk)
479{
480 int i, ret;
481
482 ret = security_locked_down(LOCKDOWN_KPROBES);
483 if (ret)
484 return ret;
485
486 if (trace_kprobe_is_registered(tk))
487 return -EINVAL;
488
489 if (within_notrace_func(tk)) {
490 pr_warn("Could not probe notrace function %ps\n",
491 (void *)trace_kprobe_address(tk));
492 return -EINVAL;
493 }
494
495 for (i = 0; i < tk->tp.nr_args; i++) {
496 ret = traceprobe_update_arg(&tk->tp.args[i]);
497 if (ret)
498 return ret;
499 }
500
501 /* Set/clear disabled flag according to tp->flag */
502 if (trace_probe_is_enabled(&tk->tp))
503 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
504 else
505 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
506
507 if (trace_kprobe_is_return(tk))
508 ret = register_kretprobe(&tk->rp);
509 else
510 ret = register_kprobe(&tk->rp.kp);
511
512 return ret;
513}
514
515/* Internal unregister function - just handle k*probes and flags */
516static void __unregister_trace_kprobe(struct trace_kprobe *tk)
517{
518 if (trace_kprobe_is_registered(tk)) {
519 if (trace_kprobe_is_return(tk))
520 unregister_kretprobe(&tk->rp);
521 else
522 unregister_kprobe(&tk->rp.kp);
523 /* Cleanup kprobe for reuse and mark it unregistered */
524 INIT_HLIST_NODE(&tk->rp.kp.hlist);
525 INIT_LIST_HEAD(&tk->rp.kp.list);
526 if (tk->rp.kp.symbol_name)
527 tk->rp.kp.addr = NULL;
528 }
529}
530
531/* Unregister a trace_probe and probe_event */
532static int unregister_trace_kprobe(struct trace_kprobe *tk)
533{
534 /* If other probes are on the event, just unregister kprobe */
535 if (trace_probe_has_sibling(&tk->tp))
536 goto unreg;
537
538 /* Enabled event can not be unregistered */
539 if (trace_probe_is_enabled(&tk->tp))
540 return -EBUSY;
541
542 /* If there's a reference to the dynamic event */
543 if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp)))
544 return -EBUSY;
545
546 /* Will fail if probe is being used by ftrace or perf */
547 if (unregister_kprobe_event(tk))
548 return -EBUSY;
549
550unreg:
551 __unregister_trace_kprobe(tk);
552 dyn_event_remove(&tk->devent);
553 trace_probe_unlink(&tk->tp);
554
555 return 0;
556}
557
558static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
559 struct trace_kprobe *comp)
560{
561 struct trace_probe_event *tpe = orig->tp.event;
562 int i;
563
564 list_for_each_entry(orig, &tpe->probes, tp.list) {
565 if (strcmp(trace_kprobe_symbol(orig),
566 trace_kprobe_symbol(comp)) ||
567 trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
568 continue;
569
570 /*
571 * trace_probe_compare_arg_type() ensured that nr_args and
572 * each argument name and type are same. Let's compare comm.
573 */
574 for (i = 0; i < orig->tp.nr_args; i++) {
575 if (strcmp(orig->tp.args[i].comm,
576 comp->tp.args[i].comm))
577 break;
578 }
579
580 if (i == orig->tp.nr_args)
581 return true;
582 }
583
584 return false;
585}
586
587static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
588{
589 int ret;
590
591 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
592 if (ret) {
593 /* Note that argument starts index = 2 */
594 trace_probe_log_set_index(ret + 1);
595 trace_probe_log_err(0, DIFF_ARG_TYPE);
596 return -EEXIST;
597 }
598 if (trace_kprobe_has_same_kprobe(to, tk)) {
599 trace_probe_log_set_index(0);
600 trace_probe_log_err(0, SAME_PROBE);
601 return -EEXIST;
602 }
603
604 /* Append to existing event */
605 ret = trace_probe_append(&tk->tp, &to->tp);
606 if (ret)
607 return ret;
608
609 /* Register k*probe */
610 ret = __register_trace_kprobe(tk);
611 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
612 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
613 ret = 0;
614 }
615
616 if (ret)
617 trace_probe_unlink(&tk->tp);
618 else
619 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
620
621 return ret;
622}
623
624/* Register a trace_probe and probe_event */
625static int register_trace_kprobe(struct trace_kprobe *tk)
626{
627 struct trace_kprobe *old_tk;
628 int ret;
629
630 mutex_lock(&event_mutex);
631
632 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
633 trace_probe_group_name(&tk->tp));
634 if (old_tk) {
635 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
636 trace_probe_log_set_index(0);
637 trace_probe_log_err(0, DIFF_PROBE_TYPE);
638 ret = -EEXIST;
639 } else {
640 ret = append_trace_kprobe(tk, old_tk);
641 }
642 goto end;
643 }
644
645 /* Register new event */
646 ret = register_kprobe_event(tk);
647 if (ret) {
648 if (ret == -EEXIST) {
649 trace_probe_log_set_index(0);
650 trace_probe_log_err(0, EVENT_EXIST);
651 } else
652 pr_warn("Failed to register probe event(%d)\n", ret);
653 goto end;
654 }
655
656 /* Register k*probe */
657 ret = __register_trace_kprobe(tk);
658 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
659 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
660 ret = 0;
661 }
662
663 if (ret < 0)
664 unregister_kprobe_event(tk);
665 else
666 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
667
668end:
669 mutex_unlock(&event_mutex);
670 return ret;
671}
672
673/* Module notifier call back, checking event on the module */
674static int trace_kprobe_module_callback(struct notifier_block *nb,
675 unsigned long val, void *data)
676{
677 struct module *mod = data;
678 struct dyn_event *pos;
679 struct trace_kprobe *tk;
680 int ret;
681
682 if (val != MODULE_STATE_COMING)
683 return NOTIFY_DONE;
684
685 /* Update probes on coming module */
686 mutex_lock(&event_mutex);
687 for_each_trace_kprobe(tk, pos) {
688 if (trace_kprobe_within_module(tk, mod)) {
689 /* Don't need to check busy - this should have gone. */
690 __unregister_trace_kprobe(tk);
691 ret = __register_trace_kprobe(tk);
692 if (ret)
693 pr_warn("Failed to re-register probe %s on %s: %d\n",
694 trace_probe_name(&tk->tp),
695 module_name(mod), ret);
696 }
697 }
698 mutex_unlock(&event_mutex);
699
700 return NOTIFY_DONE;
701}
702
703static struct notifier_block trace_kprobe_module_nb = {
704 .notifier_call = trace_kprobe_module_callback,
705 .priority = 1 /* Invoked after kprobe module callback */
706};
707
708static int count_symbols(void *data, unsigned long unused)
709{
710 unsigned int *count = data;
711
712 (*count)++;
713
714 return 0;
715}
716
717struct sym_count_ctx {
718 unsigned int count;
719 const char *name;
720};
721
722static int count_mod_symbols(void *data, const char *name, unsigned long unused)
723{
724 struct sym_count_ctx *ctx = data;
725
726 if (strcmp(name, ctx->name) == 0)
727 ctx->count++;
728
729 return 0;
730}
731
732static unsigned int number_of_same_symbols(char *func_name)
733{
734 struct sym_count_ctx ctx = { .count = 0, .name = func_name };
735
736 kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count);
737
738 module_kallsyms_on_each_symbol(NULL, count_mod_symbols, &ctx);
739
740 return ctx.count;
741}
742
743static int trace_kprobe_entry_handler(struct kretprobe_instance *ri,
744 struct pt_regs *regs);
745
746static int __trace_kprobe_create(int argc, const char *argv[])
747{
748 /*
749 * Argument syntax:
750 * - Add kprobe:
751 * p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
752 * - Add kretprobe:
753 * r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
754 * Or
755 * p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
756 *
757 * Fetch args:
758 * $retval : fetch return value
759 * $stack : fetch stack address
760 * $stackN : fetch Nth of stack (N:0-)
761 * $comm : fetch current task comm
762 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
763 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
764 * %REG : fetch register REG
765 * Dereferencing memory fetch:
766 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
767 * Alias name of args:
768 * NAME=FETCHARG : set NAME as alias of FETCHARG.
769 * Type of args:
770 * FETCHARG:TYPE : use TYPE instead of unsigned long.
771 */
772 struct trace_kprobe *tk = NULL;
773 int i, len, new_argc = 0, ret = 0;
774 bool is_return = false;
775 char *symbol = NULL, *tmp = NULL;
776 const char **new_argv = NULL;
777 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
778 enum probe_print_type ptype;
779 int maxactive = 0;
780 long offset = 0;
781 void *addr = NULL;
782 char buf[MAX_EVENT_NAME_LEN];
783 char gbuf[MAX_EVENT_NAME_LEN];
784 char abuf[MAX_BTF_ARGS_LEN];
785 struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
786
787 switch (argv[0][0]) {
788 case 'r':
789 is_return = true;
790 break;
791 case 'p':
792 break;
793 default:
794 return -ECANCELED;
795 }
796 if (argc < 2)
797 return -ECANCELED;
798
799 trace_probe_log_init("trace_kprobe", argc, argv);
800
801 event = strchr(&argv[0][1], ':');
802 if (event)
803 event++;
804
805 if (isdigit(argv[0][1])) {
806 if (!is_return) {
807 trace_probe_log_err(1, BAD_MAXACT_TYPE);
808 goto parse_error;
809 }
810 if (event)
811 len = event - &argv[0][1] - 1;
812 else
813 len = strlen(&argv[0][1]);
814 if (len > MAX_EVENT_NAME_LEN - 1) {
815 trace_probe_log_err(1, BAD_MAXACT);
816 goto parse_error;
817 }
818 memcpy(buf, &argv[0][1], len);
819 buf[len] = '\0';
820 ret = kstrtouint(buf, 0, &maxactive);
821 if (ret || !maxactive) {
822 trace_probe_log_err(1, BAD_MAXACT);
823 goto parse_error;
824 }
825 /* kretprobes instances are iterated over via a list. The
826 * maximum should stay reasonable.
827 */
828 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
829 trace_probe_log_err(1, MAXACT_TOO_BIG);
830 goto parse_error;
831 }
832 }
833
834 /* try to parse an address. if that fails, try to read the
835 * input as a symbol. */
836 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
837 trace_probe_log_set_index(1);
838 /* Check whether uprobe event specified */
839 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
840 ret = -ECANCELED;
841 goto error;
842 }
843 /* a symbol specified */
844 symbol = kstrdup(argv[1], GFP_KERNEL);
845 if (!symbol)
846 return -ENOMEM;
847
848 tmp = strchr(symbol, '%');
849 if (tmp) {
850 if (!strcmp(tmp, "%return")) {
851 *tmp = '\0';
852 is_return = true;
853 } else {
854 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
855 goto parse_error;
856 }
857 }
858
859 /* TODO: support .init module functions */
860 ret = traceprobe_split_symbol_offset(symbol, &offset);
861 if (ret || offset < 0 || offset > UINT_MAX) {
862 trace_probe_log_err(0, BAD_PROBE_ADDR);
863 goto parse_error;
864 }
865 if (is_return)
866 ctx.flags |= TPARG_FL_RETURN;
867 ret = kprobe_on_func_entry(NULL, symbol, offset);
868 if (ret == 0 && !is_return)
869 ctx.flags |= TPARG_FL_FENTRY;
870 /* Defer the ENOENT case until register kprobe */
871 if (ret == -EINVAL && is_return) {
872 trace_probe_log_err(0, BAD_RETPROBE);
873 goto parse_error;
874 }
875 }
876
877 if (symbol && !strchr(symbol, ':')) {
878 unsigned int count;
879
880 count = number_of_same_symbols(symbol);
881 if (count > 1) {
882 /*
883 * Users should use ADDR to remove the ambiguity of
884 * using KSYM only.
885 */
886 trace_probe_log_err(0, NON_UNIQ_SYMBOL);
887 ret = -EADDRNOTAVAIL;
888
889 goto error;
890 } else if (count == 0) {
891 /*
892 * We can return ENOENT earlier than when register the
893 * kprobe.
894 */
895 trace_probe_log_err(0, BAD_PROBE_ADDR);
896 ret = -ENOENT;
897
898 goto error;
899 }
900 }
901
902 trace_probe_log_set_index(0);
903 if (event) {
904 ret = traceprobe_parse_event_name(&event, &group, gbuf,
905 event - argv[0]);
906 if (ret)
907 goto parse_error;
908 }
909
910 if (!event) {
911 /* Make a new event name */
912 if (symbol)
913 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
914 is_return ? 'r' : 'p', symbol, offset);
915 else
916 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
917 is_return ? 'r' : 'p', addr);
918 sanitize_event_name(buf);
919 event = buf;
920 }
921
922 argc -= 2; argv += 2;
923 ctx.funcname = symbol;
924 new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,
925 abuf, MAX_BTF_ARGS_LEN, &ctx);
926 if (IS_ERR(new_argv)) {
927 ret = PTR_ERR(new_argv);
928 new_argv = NULL;
929 goto out;
930 }
931 if (new_argv) {
932 argc = new_argc;
933 argv = new_argv;
934 }
935
936 /* setup a probe */
937 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
938 argc, is_return);
939 if (IS_ERR(tk)) {
940 ret = PTR_ERR(tk);
941 /* This must return -ENOMEM, else there is a bug */
942 WARN_ON_ONCE(ret != -ENOMEM);
943 goto out; /* We know tk is not allocated */
944 }
945
946 /* parse arguments */
947 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
948 trace_probe_log_set_index(i + 2);
949 ctx.offset = 0;
950 ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], &ctx);
951 if (ret)
952 goto error; /* This can be -ENOMEM */
953 }
954 /* entry handler for kretprobe */
955 if (is_return && tk->tp.entry_arg) {
956 tk->rp.entry_handler = trace_kprobe_entry_handler;
957 tk->rp.data_size = traceprobe_get_entry_data_size(&tk->tp);
958 }
959
960 ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
961 ret = traceprobe_set_print_fmt(&tk->tp, ptype);
962 if (ret < 0)
963 goto error;
964
965 ret = register_trace_kprobe(tk);
966 if (ret) {
967 trace_probe_log_set_index(1);
968 if (ret == -EILSEQ)
969 trace_probe_log_err(0, BAD_INSN_BNDRY);
970 else if (ret == -ENOENT)
971 trace_probe_log_err(0, BAD_PROBE_ADDR);
972 else if (ret != -ENOMEM && ret != -EEXIST)
973 trace_probe_log_err(0, FAIL_REG_PROBE);
974 goto error;
975 }
976
977out:
978 traceprobe_finish_parse(&ctx);
979 trace_probe_log_clear();
980 kfree(new_argv);
981 kfree(symbol);
982 return ret;
983
984parse_error:
985 ret = -EINVAL;
986error:
987 free_trace_kprobe(tk);
988 goto out;
989}
990
991static int trace_kprobe_create(const char *raw_command)
992{
993 return trace_probe_create(raw_command, __trace_kprobe_create);
994}
995
996static int create_or_delete_trace_kprobe(const char *raw_command)
997{
998 int ret;
999
1000 if (raw_command[0] == '-')
1001 return dyn_event_release(raw_command, &trace_kprobe_ops);
1002
1003 ret = trace_kprobe_create(raw_command);
1004 return ret == -ECANCELED ? -EINVAL : ret;
1005}
1006
1007static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
1008{
1009 return create_or_delete_trace_kprobe(cmd->seq.buffer);
1010}
1011
1012/**
1013 * kprobe_event_cmd_init - Initialize a kprobe event command object
1014 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1015 * @buf: A pointer to the buffer used to build the command
1016 * @maxlen: The length of the buffer passed in @buf
1017 *
1018 * Initialize a synthetic event command object. Use this before
1019 * calling any of the other kprobe_event functions.
1020 */
1021void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1022{
1023 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
1024 trace_kprobe_run_command);
1025}
1026EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
1027
1028/**
1029 * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
1030 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1031 * @kretprobe: Is this a return probe?
1032 * @name: The name of the kprobe event
1033 * @loc: The location of the kprobe event
1034 * @...: Variable number of arg (pairs), one pair for each field
1035 *
1036 * NOTE: Users normally won't want to call this function directly, but
1037 * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
1038 * adds a NULL to the end of the arg list. If this function is used
1039 * directly, make sure the last arg in the variable arg list is NULL.
1040 *
1041 * Generate a kprobe event command to be executed by
1042 * kprobe_event_gen_cmd_end(). This function can be used to generate the
1043 * complete command or only the first part of it; in the latter case,
1044 * kprobe_event_add_fields() can be used to add more fields following this.
1045 *
1046 * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
1047 * returns -EINVAL if @loc == NULL.
1048 *
1049 * Return: 0 if successful, error otherwise.
1050 */
1051int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
1052 const char *name, const char *loc, ...)
1053{
1054 char buf[MAX_EVENT_NAME_LEN];
1055 struct dynevent_arg arg;
1056 va_list args;
1057 int ret;
1058
1059 if (cmd->type != DYNEVENT_TYPE_KPROBE)
1060 return -EINVAL;
1061
1062 if (!loc)
1063 return -EINVAL;
1064
1065 if (kretprobe)
1066 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
1067 else
1068 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
1069
1070 ret = dynevent_str_add(cmd, buf);
1071 if (ret)
1072 return ret;
1073
1074 dynevent_arg_init(&arg, 0);
1075 arg.str = loc;
1076 ret = dynevent_arg_add(cmd, &arg, NULL);
1077 if (ret)
1078 return ret;
1079
1080 va_start(args, loc);
1081 for (;;) {
1082 const char *field;
1083
1084 field = va_arg(args, const char *);
1085 if (!field)
1086 break;
1087
1088 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1089 ret = -EINVAL;
1090 break;
1091 }
1092
1093 arg.str = field;
1094 ret = dynevent_arg_add(cmd, &arg, NULL);
1095 if (ret)
1096 break;
1097 }
1098 va_end(args);
1099
1100 return ret;
1101}
1102EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1103
1104/**
1105 * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1106 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1107 * @...: Variable number of arg (pairs), one pair for each field
1108 *
1109 * NOTE: Users normally won't want to call this function directly, but
1110 * rather use the kprobe_event_add_fields() wrapper, which
1111 * automatically adds a NULL to the end of the arg list. If this
1112 * function is used directly, make sure the last arg in the variable
1113 * arg list is NULL.
1114 *
1115 * Add probe fields to an existing kprobe command using a variable
1116 * list of args. Fields are added in the same order they're listed.
1117 *
1118 * Return: 0 if successful, error otherwise.
1119 */
1120int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1121{
1122 struct dynevent_arg arg;
1123 va_list args;
1124 int ret = 0;
1125
1126 if (cmd->type != DYNEVENT_TYPE_KPROBE)
1127 return -EINVAL;
1128
1129 dynevent_arg_init(&arg, 0);
1130
1131 va_start(args, cmd);
1132 for (;;) {
1133 const char *field;
1134
1135 field = va_arg(args, const char *);
1136 if (!field)
1137 break;
1138
1139 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1140 ret = -EINVAL;
1141 break;
1142 }
1143
1144 arg.str = field;
1145 ret = dynevent_arg_add(cmd, &arg, NULL);
1146 if (ret)
1147 break;
1148 }
1149 va_end(args);
1150
1151 return ret;
1152}
1153EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1154
1155/**
1156 * kprobe_event_delete - Delete a kprobe event
1157 * @name: The name of the kprobe event to delete
1158 *
1159 * Delete a kprobe event with the give @name from kernel code rather
1160 * than directly from the command line.
1161 *
1162 * Return: 0 if successful, error otherwise.
1163 */
1164int kprobe_event_delete(const char *name)
1165{
1166 char buf[MAX_EVENT_NAME_LEN];
1167
1168 snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1169
1170 return create_or_delete_trace_kprobe(buf);
1171}
1172EXPORT_SYMBOL_GPL(kprobe_event_delete);
1173
1174static int trace_kprobe_release(struct dyn_event *ev)
1175{
1176 struct trace_kprobe *tk = to_trace_kprobe(ev);
1177 int ret = unregister_trace_kprobe(tk);
1178
1179 if (!ret)
1180 free_trace_kprobe(tk);
1181 return ret;
1182}
1183
1184static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1185{
1186 struct trace_kprobe *tk = to_trace_kprobe(ev);
1187 int i;
1188
1189 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1190 if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1191 seq_printf(m, "%d", tk->rp.maxactive);
1192 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1193 trace_probe_name(&tk->tp));
1194
1195 if (!tk->symbol)
1196 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1197 else if (tk->rp.kp.offset)
1198 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1199 tk->rp.kp.offset);
1200 else
1201 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1202
1203 for (i = 0; i < tk->tp.nr_args; i++)
1204 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1205 seq_putc(m, '\n');
1206
1207 return 0;
1208}
1209
1210static int probes_seq_show(struct seq_file *m, void *v)
1211{
1212 struct dyn_event *ev = v;
1213
1214 if (!is_trace_kprobe(ev))
1215 return 0;
1216
1217 return trace_kprobe_show(m, ev);
1218}
1219
1220static const struct seq_operations probes_seq_op = {
1221 .start = dyn_event_seq_start,
1222 .next = dyn_event_seq_next,
1223 .stop = dyn_event_seq_stop,
1224 .show = probes_seq_show
1225};
1226
1227static int probes_open(struct inode *inode, struct file *file)
1228{
1229 int ret;
1230
1231 ret = security_locked_down(LOCKDOWN_TRACEFS);
1232 if (ret)
1233 return ret;
1234
1235 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1236 ret = dyn_events_release_all(&trace_kprobe_ops);
1237 if (ret < 0)
1238 return ret;
1239 }
1240
1241 return seq_open(file, &probes_seq_op);
1242}
1243
1244static ssize_t probes_write(struct file *file, const char __user *buffer,
1245 size_t count, loff_t *ppos)
1246{
1247 return trace_parse_run_command(file, buffer, count, ppos,
1248 create_or_delete_trace_kprobe);
1249}
1250
1251static const struct file_operations kprobe_events_ops = {
1252 .owner = THIS_MODULE,
1253 .open = probes_open,
1254 .read = seq_read,
1255 .llseek = seq_lseek,
1256 .release = seq_release,
1257 .write = probes_write,
1258};
1259
1260static unsigned long trace_kprobe_missed(struct trace_kprobe *tk)
1261{
1262 return trace_kprobe_is_return(tk) ?
1263 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
1264}
1265
1266/* Probes profiling interfaces */
1267static int probes_profile_seq_show(struct seq_file *m, void *v)
1268{
1269 struct dyn_event *ev = v;
1270 struct trace_kprobe *tk;
1271 unsigned long nmissed;
1272
1273 if (!is_trace_kprobe(ev))
1274 return 0;
1275
1276 tk = to_trace_kprobe(ev);
1277 nmissed = trace_kprobe_missed(tk);
1278 seq_printf(m, " %-44s %15lu %15lu\n",
1279 trace_probe_name(&tk->tp),
1280 trace_kprobe_nhit(tk),
1281 nmissed);
1282
1283 return 0;
1284}
1285
1286static const struct seq_operations profile_seq_op = {
1287 .start = dyn_event_seq_start,
1288 .next = dyn_event_seq_next,
1289 .stop = dyn_event_seq_stop,
1290 .show = probes_profile_seq_show
1291};
1292
1293static int profile_open(struct inode *inode, struct file *file)
1294{
1295 int ret;
1296
1297 ret = security_locked_down(LOCKDOWN_TRACEFS);
1298 if (ret)
1299 return ret;
1300
1301 return seq_open(file, &profile_seq_op);
1302}
1303
1304static const struct file_operations kprobe_profile_ops = {
1305 .owner = THIS_MODULE,
1306 .open = profile_open,
1307 .read = seq_read,
1308 .llseek = seq_lseek,
1309 .release = seq_release,
1310};
1311
1312/* Note that we don't verify it, since the code does not come from user space */
1313static int
1314process_fetch_insn(struct fetch_insn *code, void *rec, void *edata,
1315 void *dest, void *base)
1316{
1317 struct pt_regs *regs = rec;
1318 unsigned long val;
1319 int ret;
1320
1321retry:
1322 /* 1st stage: get value from context */
1323 switch (code->op) {
1324 case FETCH_OP_REG:
1325 val = regs_get_register(regs, code->param);
1326 break;
1327 case FETCH_OP_STACK:
1328 val = regs_get_kernel_stack_nth(regs, code->param);
1329 break;
1330 case FETCH_OP_STACKP:
1331 val = kernel_stack_pointer(regs);
1332 break;
1333 case FETCH_OP_RETVAL:
1334 val = regs_return_value(regs);
1335 break;
1336#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1337 case FETCH_OP_ARG:
1338 val = regs_get_kernel_argument(regs, code->param);
1339 break;
1340 case FETCH_OP_EDATA:
1341 val = *(unsigned long *)((unsigned long)edata + code->offset);
1342 break;
1343#endif
1344 case FETCH_NOP_SYMBOL: /* Ignore a place holder */
1345 code++;
1346 goto retry;
1347 default:
1348 ret = process_common_fetch_insn(code, &val);
1349 if (ret < 0)
1350 return ret;
1351 }
1352 code++;
1353
1354 return process_fetch_insn_bottom(code, val, dest, base);
1355}
1356NOKPROBE_SYMBOL(process_fetch_insn)
1357
1358/* Kprobe handler */
1359static nokprobe_inline void
1360__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1361 struct trace_event_file *trace_file)
1362{
1363 struct kprobe_trace_entry_head *entry;
1364 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1365 struct trace_event_buffer fbuffer;
1366 int dsize;
1367
1368 WARN_ON(call != trace_file->event_call);
1369
1370 if (trace_trigger_soft_disabled(trace_file))
1371 return;
1372
1373 dsize = __get_data_size(&tk->tp, regs, NULL);
1374
1375 entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1376 sizeof(*entry) + tk->tp.size + dsize);
1377 if (!entry)
1378 return;
1379
1380 fbuffer.regs = regs;
1381 entry->ip = (unsigned long)tk->rp.kp.addr;
1382 store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize);
1383
1384 trace_event_buffer_commit(&fbuffer);
1385}
1386
1387static void
1388kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1389{
1390 struct event_file_link *link;
1391
1392 trace_probe_for_each_link_rcu(link, &tk->tp)
1393 __kprobe_trace_func(tk, regs, link->file);
1394}
1395NOKPROBE_SYMBOL(kprobe_trace_func);
1396
1397/* Kretprobe handler */
1398
1399static int trace_kprobe_entry_handler(struct kretprobe_instance *ri,
1400 struct pt_regs *regs)
1401{
1402 struct kretprobe *rp = get_kretprobe(ri);
1403 struct trace_kprobe *tk;
1404
1405 /*
1406 * There is a small chance that get_kretprobe(ri) returns NULL when
1407 * the kretprobe is unregister on another CPU between kretprobe's
1408 * trampoline_handler and this function.
1409 */
1410 if (unlikely(!rp))
1411 return -ENOENT;
1412
1413 tk = container_of(rp, struct trace_kprobe, rp);
1414
1415 /* store argument values into ri->data as entry data */
1416 if (tk->tp.entry_arg)
1417 store_trace_entry_data(ri->data, &tk->tp, regs);
1418
1419 return 0;
1420}
1421
1422
1423static nokprobe_inline void
1424__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1425 struct pt_regs *regs,
1426 struct trace_event_file *trace_file)
1427{
1428 struct kretprobe_trace_entry_head *entry;
1429 struct trace_event_buffer fbuffer;
1430 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1431 int dsize;
1432
1433 WARN_ON(call != trace_file->event_call);
1434
1435 if (trace_trigger_soft_disabled(trace_file))
1436 return;
1437
1438 dsize = __get_data_size(&tk->tp, regs, ri->data);
1439
1440 entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1441 sizeof(*entry) + tk->tp.size + dsize);
1442 if (!entry)
1443 return;
1444
1445 fbuffer.regs = regs;
1446 entry->func = (unsigned long)tk->rp.kp.addr;
1447 entry->ret_ip = get_kretprobe_retaddr(ri);
1448 store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize);
1449
1450 trace_event_buffer_commit(&fbuffer);
1451}
1452
1453static void
1454kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1455 struct pt_regs *regs)
1456{
1457 struct event_file_link *link;
1458
1459 trace_probe_for_each_link_rcu(link, &tk->tp)
1460 __kretprobe_trace_func(tk, ri, regs, link->file);
1461}
1462NOKPROBE_SYMBOL(kretprobe_trace_func);
1463
1464/* Event entry printers */
1465static enum print_line_t
1466print_kprobe_event(struct trace_iterator *iter, int flags,
1467 struct trace_event *event)
1468{
1469 struct kprobe_trace_entry_head *field;
1470 struct trace_seq *s = &iter->seq;
1471 struct trace_probe *tp;
1472
1473 field = (struct kprobe_trace_entry_head *)iter->ent;
1474 tp = trace_probe_primary_from_call(
1475 container_of(event, struct trace_event_call, event));
1476 if (WARN_ON_ONCE(!tp))
1477 goto out;
1478
1479 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1480
1481 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1482 goto out;
1483
1484 trace_seq_putc(s, ')');
1485
1486 if (trace_probe_print_args(s, tp->args, tp->nr_args,
1487 (u8 *)&field[1], field) < 0)
1488 goto out;
1489
1490 trace_seq_putc(s, '\n');
1491 out:
1492 return trace_handle_return(s);
1493}
1494
1495static enum print_line_t
1496print_kretprobe_event(struct trace_iterator *iter, int flags,
1497 struct trace_event *event)
1498{
1499 struct kretprobe_trace_entry_head *field;
1500 struct trace_seq *s = &iter->seq;
1501 struct trace_probe *tp;
1502
1503 field = (struct kretprobe_trace_entry_head *)iter->ent;
1504 tp = trace_probe_primary_from_call(
1505 container_of(event, struct trace_event_call, event));
1506 if (WARN_ON_ONCE(!tp))
1507 goto out;
1508
1509 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1510
1511 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1512 goto out;
1513
1514 trace_seq_puts(s, " <- ");
1515
1516 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1517 goto out;
1518
1519 trace_seq_putc(s, ')');
1520
1521 if (trace_probe_print_args(s, tp->args, tp->nr_args,
1522 (u8 *)&field[1], field) < 0)
1523 goto out;
1524
1525 trace_seq_putc(s, '\n');
1526
1527 out:
1528 return trace_handle_return(s);
1529}
1530
1531
1532static int kprobe_event_define_fields(struct trace_event_call *event_call)
1533{
1534 int ret;
1535 struct kprobe_trace_entry_head field;
1536 struct trace_probe *tp;
1537
1538 tp = trace_probe_primary_from_call(event_call);
1539 if (WARN_ON_ONCE(!tp))
1540 return -ENOENT;
1541
1542 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1543
1544 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1545}
1546
1547static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1548{
1549 int ret;
1550 struct kretprobe_trace_entry_head field;
1551 struct trace_probe *tp;
1552
1553 tp = trace_probe_primary_from_call(event_call);
1554 if (WARN_ON_ONCE(!tp))
1555 return -ENOENT;
1556
1557 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1558 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1559
1560 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1561}
1562
1563#ifdef CONFIG_PERF_EVENTS
1564
1565/* Kprobe profile handler */
1566static int
1567kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1568{
1569 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1570 struct kprobe_trace_entry_head *entry;
1571 struct hlist_head *head;
1572 int size, __size, dsize;
1573 int rctx;
1574
1575 if (bpf_prog_array_valid(call)) {
1576 unsigned long orig_ip = instruction_pointer(regs);
1577 int ret;
1578
1579 ret = trace_call_bpf(call, regs);
1580
1581 /*
1582 * We need to check and see if we modified the pc of the
1583 * pt_regs, and if so return 1 so that we don't do the
1584 * single stepping.
1585 */
1586 if (orig_ip != instruction_pointer(regs))
1587 return 1;
1588 if (!ret)
1589 return 0;
1590 }
1591
1592 head = this_cpu_ptr(call->perf_events);
1593 if (hlist_empty(head))
1594 return 0;
1595
1596 dsize = __get_data_size(&tk->tp, regs, NULL);
1597 __size = sizeof(*entry) + tk->tp.size + dsize;
1598 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1599 size -= sizeof(u32);
1600
1601 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1602 if (!entry)
1603 return 0;
1604
1605 entry->ip = (unsigned long)tk->rp.kp.addr;
1606 memset(&entry[1], 0, dsize);
1607 store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize);
1608 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1609 head, NULL);
1610 return 0;
1611}
1612NOKPROBE_SYMBOL(kprobe_perf_func);
1613
1614/* Kretprobe profile handler */
1615static void
1616kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1617 struct pt_regs *regs)
1618{
1619 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1620 struct kretprobe_trace_entry_head *entry;
1621 struct hlist_head *head;
1622 int size, __size, dsize;
1623 int rctx;
1624
1625 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1626 return;
1627
1628 head = this_cpu_ptr(call->perf_events);
1629 if (hlist_empty(head))
1630 return;
1631
1632 dsize = __get_data_size(&tk->tp, regs, ri->data);
1633 __size = sizeof(*entry) + tk->tp.size + dsize;
1634 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1635 size -= sizeof(u32);
1636
1637 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1638 if (!entry)
1639 return;
1640
1641 entry->func = (unsigned long)tk->rp.kp.addr;
1642 entry->ret_ip = get_kretprobe_retaddr(ri);
1643 store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize);
1644 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1645 head, NULL);
1646}
1647NOKPROBE_SYMBOL(kretprobe_perf_func);
1648
1649int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1650 const char **symbol, u64 *probe_offset,
1651 u64 *probe_addr, unsigned long *missed,
1652 bool perf_type_tracepoint)
1653{
1654 const char *pevent = trace_event_name(event->tp_event);
1655 const char *group = event->tp_event->class->system;
1656 struct trace_kprobe *tk;
1657
1658 if (perf_type_tracepoint)
1659 tk = find_trace_kprobe(pevent, group);
1660 else
1661 tk = trace_kprobe_primary_from_call(event->tp_event);
1662 if (!tk)
1663 return -EINVAL;
1664
1665 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1666 : BPF_FD_TYPE_KPROBE;
1667 *probe_offset = tk->rp.kp.offset;
1668 *probe_addr = kallsyms_show_value(current_cred()) ?
1669 (unsigned long)tk->rp.kp.addr : 0;
1670 *symbol = tk->symbol;
1671 if (missed)
1672 *missed = trace_kprobe_missed(tk);
1673 return 0;
1674}
1675#endif /* CONFIG_PERF_EVENTS */
1676
1677/*
1678 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1679 *
1680 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1681 * lockless, but we can't race with this __init function.
1682 */
1683static int kprobe_register(struct trace_event_call *event,
1684 enum trace_reg type, void *data)
1685{
1686 struct trace_event_file *file = data;
1687
1688 switch (type) {
1689 case TRACE_REG_REGISTER:
1690 return enable_trace_kprobe(event, file);
1691 case TRACE_REG_UNREGISTER:
1692 return disable_trace_kprobe(event, file);
1693
1694#ifdef CONFIG_PERF_EVENTS
1695 case TRACE_REG_PERF_REGISTER:
1696 return enable_trace_kprobe(event, NULL);
1697 case TRACE_REG_PERF_UNREGISTER:
1698 return disable_trace_kprobe(event, NULL);
1699 case TRACE_REG_PERF_OPEN:
1700 case TRACE_REG_PERF_CLOSE:
1701 case TRACE_REG_PERF_ADD:
1702 case TRACE_REG_PERF_DEL:
1703 return 0;
1704#endif
1705 }
1706 return 0;
1707}
1708
1709static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1710{
1711 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1712 int ret = 0;
1713
1714 raw_cpu_inc(*tk->nhit);
1715
1716 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1717 kprobe_trace_func(tk, regs);
1718#ifdef CONFIG_PERF_EVENTS
1719 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1720 ret = kprobe_perf_func(tk, regs);
1721#endif
1722 return ret;
1723}
1724NOKPROBE_SYMBOL(kprobe_dispatcher);
1725
1726static int
1727kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1728{
1729 struct kretprobe *rp = get_kretprobe(ri);
1730 struct trace_kprobe *tk;
1731
1732 /*
1733 * There is a small chance that get_kretprobe(ri) returns NULL when
1734 * the kretprobe is unregister on another CPU between kretprobe's
1735 * trampoline_handler and this function.
1736 */
1737 if (unlikely(!rp))
1738 return 0;
1739
1740 tk = container_of(rp, struct trace_kprobe, rp);
1741 raw_cpu_inc(*tk->nhit);
1742
1743 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1744 kretprobe_trace_func(tk, ri, regs);
1745#ifdef CONFIG_PERF_EVENTS
1746 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1747 kretprobe_perf_func(tk, ri, regs);
1748#endif
1749 return 0; /* We don't tweak kernel, so just return 0 */
1750}
1751NOKPROBE_SYMBOL(kretprobe_dispatcher);
1752
1753static struct trace_event_functions kretprobe_funcs = {
1754 .trace = print_kretprobe_event
1755};
1756
1757static struct trace_event_functions kprobe_funcs = {
1758 .trace = print_kprobe_event
1759};
1760
1761static struct trace_event_fields kretprobe_fields_array[] = {
1762 { .type = TRACE_FUNCTION_TYPE,
1763 .define_fields = kretprobe_event_define_fields },
1764 {}
1765};
1766
1767static struct trace_event_fields kprobe_fields_array[] = {
1768 { .type = TRACE_FUNCTION_TYPE,
1769 .define_fields = kprobe_event_define_fields },
1770 {}
1771};
1772
1773static inline void init_trace_event_call(struct trace_kprobe *tk)
1774{
1775 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1776
1777 if (trace_kprobe_is_return(tk)) {
1778 call->event.funcs = &kretprobe_funcs;
1779 call->class->fields_array = kretprobe_fields_array;
1780 } else {
1781 call->event.funcs = &kprobe_funcs;
1782 call->class->fields_array = kprobe_fields_array;
1783 }
1784
1785 call->flags = TRACE_EVENT_FL_KPROBE;
1786 call->class->reg = kprobe_register;
1787}
1788
1789static int register_kprobe_event(struct trace_kprobe *tk)
1790{
1791 init_trace_event_call(tk);
1792
1793 return trace_probe_register_event_call(&tk->tp);
1794}
1795
1796static int unregister_kprobe_event(struct trace_kprobe *tk)
1797{
1798 return trace_probe_unregister_event_call(&tk->tp);
1799}
1800
1801#ifdef CONFIG_PERF_EVENTS
1802
1803/* create a trace_kprobe, but don't add it to global lists */
1804struct trace_event_call *
1805create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1806 bool is_return)
1807{
1808 enum probe_print_type ptype;
1809 struct trace_kprobe *tk;
1810 int ret;
1811 char *event;
1812
1813 if (func) {
1814 unsigned int count;
1815
1816 count = number_of_same_symbols(func);
1817 if (count > 1)
1818 /*
1819 * Users should use addr to remove the ambiguity of
1820 * using func only.
1821 */
1822 return ERR_PTR(-EADDRNOTAVAIL);
1823 else if (count == 0)
1824 /*
1825 * We can return ENOENT earlier than when register the
1826 * kprobe.
1827 */
1828 return ERR_PTR(-ENOENT);
1829 }
1830
1831 /*
1832 * local trace_kprobes are not added to dyn_event, so they are never
1833 * searched in find_trace_kprobe(). Therefore, there is no concern of
1834 * duplicated name here.
1835 */
1836 event = func ? func : "DUMMY_EVENT";
1837
1838 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1839 offs, 0 /* maxactive */, 0 /* nargs */,
1840 is_return);
1841
1842 if (IS_ERR(tk)) {
1843 pr_info("Failed to allocate trace_probe.(%d)\n",
1844 (int)PTR_ERR(tk));
1845 return ERR_CAST(tk);
1846 }
1847
1848 init_trace_event_call(tk);
1849
1850 ptype = trace_kprobe_is_return(tk) ?
1851 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1852 if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) {
1853 ret = -ENOMEM;
1854 goto error;
1855 }
1856
1857 ret = __register_trace_kprobe(tk);
1858 if (ret < 0)
1859 goto error;
1860
1861 return trace_probe_event_call(&tk->tp);
1862error:
1863 free_trace_kprobe(tk);
1864 return ERR_PTR(ret);
1865}
1866
1867void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1868{
1869 struct trace_kprobe *tk;
1870
1871 tk = trace_kprobe_primary_from_call(event_call);
1872 if (unlikely(!tk))
1873 return;
1874
1875 if (trace_probe_is_enabled(&tk->tp)) {
1876 WARN_ON(1);
1877 return;
1878 }
1879
1880 __unregister_trace_kprobe(tk);
1881
1882 free_trace_kprobe(tk);
1883}
1884#endif /* CONFIG_PERF_EVENTS */
1885
1886static __init void enable_boot_kprobe_events(void)
1887{
1888 struct trace_array *tr = top_trace_array();
1889 struct trace_event_file *file;
1890 struct trace_kprobe *tk;
1891 struct dyn_event *pos;
1892
1893 mutex_lock(&event_mutex);
1894 for_each_trace_kprobe(tk, pos) {
1895 list_for_each_entry(file, &tr->events, list)
1896 if (file->event_call == trace_probe_event_call(&tk->tp))
1897 trace_event_enable_disable(file, 1, 0);
1898 }
1899 mutex_unlock(&event_mutex);
1900}
1901
1902static __init void setup_boot_kprobe_events(void)
1903{
1904 char *p, *cmd = kprobe_boot_events_buf;
1905 int ret;
1906
1907 strreplace(kprobe_boot_events_buf, ',', ' ');
1908
1909 while (cmd && *cmd != '\0') {
1910 p = strchr(cmd, ';');
1911 if (p)
1912 *p++ = '\0';
1913
1914 ret = create_or_delete_trace_kprobe(cmd);
1915 if (ret)
1916 pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1917
1918 cmd = p;
1919 }
1920
1921 enable_boot_kprobe_events();
1922}
1923
1924/*
1925 * Register dynevent at core_initcall. This allows kernel to setup kprobe
1926 * events in postcore_initcall without tracefs.
1927 */
1928static __init int init_kprobe_trace_early(void)
1929{
1930 int ret;
1931
1932 ret = dyn_event_register(&trace_kprobe_ops);
1933 if (ret)
1934 return ret;
1935
1936 if (register_module_notifier(&trace_kprobe_module_nb))
1937 return -EINVAL;
1938
1939 return 0;
1940}
1941core_initcall(init_kprobe_trace_early);
1942
1943/* Make a tracefs interface for controlling probe points */
1944static __init int init_kprobe_trace(void)
1945{
1946 int ret;
1947
1948 ret = tracing_init_dentry();
1949 if (ret)
1950 return 0;
1951
1952 /* Event list interface */
1953 trace_create_file("kprobe_events", TRACE_MODE_WRITE,
1954 NULL, NULL, &kprobe_events_ops);
1955
1956 /* Profile interface */
1957 trace_create_file("kprobe_profile", TRACE_MODE_READ,
1958 NULL, NULL, &kprobe_profile_ops);
1959
1960 setup_boot_kprobe_events();
1961
1962 return 0;
1963}
1964fs_initcall(init_kprobe_trace);
1965
1966
1967#ifdef CONFIG_FTRACE_STARTUP_TEST
1968static __init struct trace_event_file *
1969find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1970{
1971 struct trace_event_file *file;
1972
1973 list_for_each_entry(file, &tr->events, list)
1974 if (file->event_call == trace_probe_event_call(&tk->tp))
1975 return file;
1976
1977 return NULL;
1978}
1979
1980/*
1981 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1982 * stage, we can do this lockless.
1983 */
1984static __init int kprobe_trace_self_tests_init(void)
1985{
1986 int ret, warn = 0;
1987 int (*target)(int, int, int, int, int, int);
1988 struct trace_kprobe *tk;
1989 struct trace_event_file *file;
1990
1991 if (tracing_is_disabled())
1992 return -ENODEV;
1993
1994 if (tracing_selftest_disabled)
1995 return 0;
1996
1997 target = kprobe_trace_selftest_target;
1998
1999 pr_info("Testing kprobe tracing: ");
2000
2001 ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
2002 if (WARN_ON_ONCE(ret)) {
2003 pr_warn("error on probing function entry.\n");
2004 warn++;
2005 } else {
2006 /* Enable trace point */
2007 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2008 if (WARN_ON_ONCE(tk == NULL)) {
2009 pr_warn("error on getting new probe.\n");
2010 warn++;
2011 } else {
2012 file = find_trace_probe_file(tk, top_trace_array());
2013 if (WARN_ON_ONCE(file == NULL)) {
2014 pr_warn("error on getting probe file.\n");
2015 warn++;
2016 } else
2017 enable_trace_kprobe(
2018 trace_probe_event_call(&tk->tp), file);
2019 }
2020 }
2021
2022 ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
2023 if (WARN_ON_ONCE(ret)) {
2024 pr_warn("error on probing function return.\n");
2025 warn++;
2026 } else {
2027 /* Enable trace point */
2028 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2029 if (WARN_ON_ONCE(tk == NULL)) {
2030 pr_warn("error on getting 2nd new probe.\n");
2031 warn++;
2032 } else {
2033 file = find_trace_probe_file(tk, top_trace_array());
2034 if (WARN_ON_ONCE(file == NULL)) {
2035 pr_warn("error on getting probe file.\n");
2036 warn++;
2037 } else
2038 enable_trace_kprobe(
2039 trace_probe_event_call(&tk->tp), file);
2040 }
2041 }
2042
2043 if (warn)
2044 goto end;
2045
2046 ret = target(1, 2, 3, 4, 5, 6);
2047
2048 /*
2049 * Not expecting an error here, the check is only to prevent the
2050 * optimizer from removing the call to target() as otherwise there
2051 * are no side-effects and the call is never performed.
2052 */
2053 if (ret != 21)
2054 warn++;
2055
2056 /* Disable trace points before removing it */
2057 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2058 if (WARN_ON_ONCE(tk == NULL)) {
2059 pr_warn("error on getting test probe.\n");
2060 warn++;
2061 } else {
2062 if (trace_kprobe_nhit(tk) != 1) {
2063 pr_warn("incorrect number of testprobe hits\n");
2064 warn++;
2065 }
2066
2067 file = find_trace_probe_file(tk, top_trace_array());
2068 if (WARN_ON_ONCE(file == NULL)) {
2069 pr_warn("error on getting probe file.\n");
2070 warn++;
2071 } else
2072 disable_trace_kprobe(
2073 trace_probe_event_call(&tk->tp), file);
2074 }
2075
2076 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2077 if (WARN_ON_ONCE(tk == NULL)) {
2078 pr_warn("error on getting 2nd test probe.\n");
2079 warn++;
2080 } else {
2081 if (trace_kprobe_nhit(tk) != 1) {
2082 pr_warn("incorrect number of testprobe2 hits\n");
2083 warn++;
2084 }
2085
2086 file = find_trace_probe_file(tk, top_trace_array());
2087 if (WARN_ON_ONCE(file == NULL)) {
2088 pr_warn("error on getting probe file.\n");
2089 warn++;
2090 } else
2091 disable_trace_kprobe(
2092 trace_probe_event_call(&tk->tp), file);
2093 }
2094
2095 ret = create_or_delete_trace_kprobe("-:testprobe");
2096 if (WARN_ON_ONCE(ret)) {
2097 pr_warn("error on deleting a probe.\n");
2098 warn++;
2099 }
2100
2101 ret = create_or_delete_trace_kprobe("-:testprobe2");
2102 if (WARN_ON_ONCE(ret)) {
2103 pr_warn("error on deleting a probe.\n");
2104 warn++;
2105 }
2106
2107end:
2108 ret = dyn_events_release_all(&trace_kprobe_ops);
2109 if (WARN_ON_ONCE(ret)) {
2110 pr_warn("error on cleaning up probes.\n");
2111 warn++;
2112 }
2113 /*
2114 * Wait for the optimizer work to finish. Otherwise it might fiddle
2115 * with probes in already freed __init text.
2116 */
2117 wait_for_kprobe_optimizer();
2118 if (warn)
2119 pr_cont("NG: Some tests are failed. Please check them.\n");
2120 else
2121 pr_cont("OK\n");
2122 return 0;
2123}
2124
2125late_initcall(kprobe_trace_self_tests_init);
2126
2127#endif