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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/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 strlcpy(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);
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 %s\n",
491 trace_kprobe_symbol(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 __trace_kprobe_create(int argc, const char *argv[])
709{
710 /*
711 * Argument syntax:
712 * - Add kprobe:
713 * p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
714 * - Add kretprobe:
715 * r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
716 * Or
717 * p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
718 *
719 * Fetch args:
720 * $retval : fetch return value
721 * $stack : fetch stack address
722 * $stackN : fetch Nth of stack (N:0-)
723 * $comm : fetch current task comm
724 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
725 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
726 * %REG : fetch register REG
727 * Dereferencing memory fetch:
728 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
729 * Alias name of args:
730 * NAME=FETCHARG : set NAME as alias of FETCHARG.
731 * Type of args:
732 * FETCHARG:TYPE : use TYPE instead of unsigned long.
733 */
734 struct trace_kprobe *tk = NULL;
735 int i, len, ret = 0;
736 bool is_return = false;
737 char *symbol = NULL, *tmp = NULL;
738 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
739 enum probe_print_type ptype;
740 int maxactive = 0;
741 long offset = 0;
742 void *addr = NULL;
743 char buf[MAX_EVENT_NAME_LEN];
744 char gbuf[MAX_EVENT_NAME_LEN];
745 unsigned int flags = TPARG_FL_KERNEL;
746
747 switch (argv[0][0]) {
748 case 'r':
749 is_return = true;
750 break;
751 case 'p':
752 break;
753 default:
754 return -ECANCELED;
755 }
756 if (argc < 2)
757 return -ECANCELED;
758
759 trace_probe_log_init("trace_kprobe", argc, argv);
760
761 event = strchr(&argv[0][1], ':');
762 if (event)
763 event++;
764
765 if (isdigit(argv[0][1])) {
766 if (!is_return) {
767 trace_probe_log_err(1, MAXACT_NO_KPROBE);
768 goto parse_error;
769 }
770 if (event)
771 len = event - &argv[0][1] - 1;
772 else
773 len = strlen(&argv[0][1]);
774 if (len > MAX_EVENT_NAME_LEN - 1) {
775 trace_probe_log_err(1, BAD_MAXACT);
776 goto parse_error;
777 }
778 memcpy(buf, &argv[0][1], len);
779 buf[len] = '\0';
780 ret = kstrtouint(buf, 0, &maxactive);
781 if (ret || !maxactive) {
782 trace_probe_log_err(1, BAD_MAXACT);
783 goto parse_error;
784 }
785 /* kretprobes instances are iterated over via a list. The
786 * maximum should stay reasonable.
787 */
788 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
789 trace_probe_log_err(1, MAXACT_TOO_BIG);
790 goto parse_error;
791 }
792 }
793
794 /* try to parse an address. if that fails, try to read the
795 * input as a symbol. */
796 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
797 trace_probe_log_set_index(1);
798 /* Check whether uprobe event specified */
799 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
800 ret = -ECANCELED;
801 goto error;
802 }
803 /* a symbol specified */
804 symbol = kstrdup(argv[1], GFP_KERNEL);
805 if (!symbol)
806 return -ENOMEM;
807
808 tmp = strchr(symbol, '%');
809 if (tmp) {
810 if (!strcmp(tmp, "%return")) {
811 *tmp = '\0';
812 is_return = true;
813 } else {
814 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
815 goto parse_error;
816 }
817 }
818
819 /* TODO: support .init module functions */
820 ret = traceprobe_split_symbol_offset(symbol, &offset);
821 if (ret || offset < 0 || offset > UINT_MAX) {
822 trace_probe_log_err(0, BAD_PROBE_ADDR);
823 goto parse_error;
824 }
825 if (is_return)
826 flags |= TPARG_FL_RETURN;
827 ret = kprobe_on_func_entry(NULL, symbol, offset);
828 if (ret == 0)
829 flags |= TPARG_FL_FENTRY;
830 /* Defer the ENOENT case until register kprobe */
831 if (ret == -EINVAL && is_return) {
832 trace_probe_log_err(0, BAD_RETPROBE);
833 goto parse_error;
834 }
835 }
836
837 trace_probe_log_set_index(0);
838 if (event) {
839 ret = traceprobe_parse_event_name(&event, &group, gbuf,
840 event - argv[0]);
841 if (ret)
842 goto parse_error;
843 }
844
845 if (!event) {
846 /* Make a new event name */
847 if (symbol)
848 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
849 is_return ? 'r' : 'p', symbol, offset);
850 else
851 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
852 is_return ? 'r' : 'p', addr);
853 sanitize_event_name(buf);
854 event = buf;
855 }
856
857 /* setup a probe */
858 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
859 argc - 2, is_return);
860 if (IS_ERR(tk)) {
861 ret = PTR_ERR(tk);
862 /* This must return -ENOMEM, else there is a bug */
863 WARN_ON_ONCE(ret != -ENOMEM);
864 goto out; /* We know tk is not allocated */
865 }
866 argc -= 2; argv += 2;
867
868 /* parse arguments */
869 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
870 trace_probe_log_set_index(i + 2);
871 ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], flags);
872 if (ret)
873 goto error; /* This can be -ENOMEM */
874 }
875
876 ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
877 ret = traceprobe_set_print_fmt(&tk->tp, ptype);
878 if (ret < 0)
879 goto error;
880
881 ret = register_trace_kprobe(tk);
882 if (ret) {
883 trace_probe_log_set_index(1);
884 if (ret == -EILSEQ)
885 trace_probe_log_err(0, BAD_INSN_BNDRY);
886 else if (ret == -ENOENT)
887 trace_probe_log_err(0, BAD_PROBE_ADDR);
888 else if (ret != -ENOMEM && ret != -EEXIST)
889 trace_probe_log_err(0, FAIL_REG_PROBE);
890 goto error;
891 }
892
893out:
894 trace_probe_log_clear();
895 kfree(symbol);
896 return ret;
897
898parse_error:
899 ret = -EINVAL;
900error:
901 free_trace_kprobe(tk);
902 goto out;
903}
904
905static int trace_kprobe_create(const char *raw_command)
906{
907 return trace_probe_create(raw_command, __trace_kprobe_create);
908}
909
910static int create_or_delete_trace_kprobe(const char *raw_command)
911{
912 int ret;
913
914 if (raw_command[0] == '-')
915 return dyn_event_release(raw_command, &trace_kprobe_ops);
916
917 ret = trace_kprobe_create(raw_command);
918 return ret == -ECANCELED ? -EINVAL : ret;
919}
920
921static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
922{
923 return create_or_delete_trace_kprobe(cmd->seq.buffer);
924}
925
926/**
927 * kprobe_event_cmd_init - Initialize a kprobe event command object
928 * @cmd: A pointer to the dynevent_cmd struct representing the new event
929 * @buf: A pointer to the buffer used to build the command
930 * @maxlen: The length of the buffer passed in @buf
931 *
932 * Initialize a synthetic event command object. Use this before
933 * calling any of the other kprobe_event functions.
934 */
935void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
936{
937 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
938 trace_kprobe_run_command);
939}
940EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
941
942/**
943 * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
944 * @cmd: A pointer to the dynevent_cmd struct representing the new event
945 * @name: The name of the kprobe event
946 * @loc: The location of the kprobe event
947 * @kretprobe: Is this a return probe?
948 * @args: Variable number of arg (pairs), one pair for each field
949 *
950 * NOTE: Users normally won't want to call this function directly, but
951 * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
952 * adds a NULL to the end of the arg list. If this function is used
953 * directly, make sure the last arg in the variable arg list is NULL.
954 *
955 * Generate a kprobe event command to be executed by
956 * kprobe_event_gen_cmd_end(). This function can be used to generate the
957 * complete command or only the first part of it; in the latter case,
958 * kprobe_event_add_fields() can be used to add more fields following this.
959 *
960 * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
961 * returns -EINVAL if @loc == NULL.
962 *
963 * Return: 0 if successful, error otherwise.
964 */
965int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
966 const char *name, const char *loc, ...)
967{
968 char buf[MAX_EVENT_NAME_LEN];
969 struct dynevent_arg arg;
970 va_list args;
971 int ret;
972
973 if (cmd->type != DYNEVENT_TYPE_KPROBE)
974 return -EINVAL;
975
976 if (!loc)
977 return -EINVAL;
978
979 if (kretprobe)
980 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
981 else
982 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
983
984 ret = dynevent_str_add(cmd, buf);
985 if (ret)
986 return ret;
987
988 dynevent_arg_init(&arg, 0);
989 arg.str = loc;
990 ret = dynevent_arg_add(cmd, &arg, NULL);
991 if (ret)
992 return ret;
993
994 va_start(args, loc);
995 for (;;) {
996 const char *field;
997
998 field = va_arg(args, const char *);
999 if (!field)
1000 break;
1001
1002 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1003 ret = -EINVAL;
1004 break;
1005 }
1006
1007 arg.str = field;
1008 ret = dynevent_arg_add(cmd, &arg, NULL);
1009 if (ret)
1010 break;
1011 }
1012 va_end(args);
1013
1014 return ret;
1015}
1016EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1017
1018/**
1019 * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1020 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1021 * @args: Variable number of arg (pairs), one pair for each field
1022 *
1023 * NOTE: Users normally won't want to call this function directly, but
1024 * rather use the kprobe_event_add_fields() wrapper, which
1025 * automatically adds a NULL to the end of the arg list. If this
1026 * function is used directly, make sure the last arg in the variable
1027 * arg list is NULL.
1028 *
1029 * Add probe fields to an existing kprobe command using a variable
1030 * list of args. Fields are added in the same order they're listed.
1031 *
1032 * Return: 0 if successful, error otherwise.
1033 */
1034int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1035{
1036 struct dynevent_arg arg;
1037 va_list args;
1038 int ret = 0;
1039
1040 if (cmd->type != DYNEVENT_TYPE_KPROBE)
1041 return -EINVAL;
1042
1043 dynevent_arg_init(&arg, 0);
1044
1045 va_start(args, cmd);
1046 for (;;) {
1047 const char *field;
1048
1049 field = va_arg(args, const char *);
1050 if (!field)
1051 break;
1052
1053 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1054 ret = -EINVAL;
1055 break;
1056 }
1057
1058 arg.str = field;
1059 ret = dynevent_arg_add(cmd, &arg, NULL);
1060 if (ret)
1061 break;
1062 }
1063 va_end(args);
1064
1065 return ret;
1066}
1067EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1068
1069/**
1070 * kprobe_event_delete - Delete a kprobe event
1071 * @name: The name of the kprobe event to delete
1072 *
1073 * Delete a kprobe event with the give @name from kernel code rather
1074 * than directly from the command line.
1075 *
1076 * Return: 0 if successful, error otherwise.
1077 */
1078int kprobe_event_delete(const char *name)
1079{
1080 char buf[MAX_EVENT_NAME_LEN];
1081
1082 snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1083
1084 return create_or_delete_trace_kprobe(buf);
1085}
1086EXPORT_SYMBOL_GPL(kprobe_event_delete);
1087
1088static int trace_kprobe_release(struct dyn_event *ev)
1089{
1090 struct trace_kprobe *tk = to_trace_kprobe(ev);
1091 int ret = unregister_trace_kprobe(tk);
1092
1093 if (!ret)
1094 free_trace_kprobe(tk);
1095 return ret;
1096}
1097
1098static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1099{
1100 struct trace_kprobe *tk = to_trace_kprobe(ev);
1101 int i;
1102
1103 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1104 if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1105 seq_printf(m, "%d", tk->rp.maxactive);
1106 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1107 trace_probe_name(&tk->tp));
1108
1109 if (!tk->symbol)
1110 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1111 else if (tk->rp.kp.offset)
1112 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1113 tk->rp.kp.offset);
1114 else
1115 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1116
1117 for (i = 0; i < tk->tp.nr_args; i++)
1118 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1119 seq_putc(m, '\n');
1120
1121 return 0;
1122}
1123
1124static int probes_seq_show(struct seq_file *m, void *v)
1125{
1126 struct dyn_event *ev = v;
1127
1128 if (!is_trace_kprobe(ev))
1129 return 0;
1130
1131 return trace_kprobe_show(m, ev);
1132}
1133
1134static const struct seq_operations probes_seq_op = {
1135 .start = dyn_event_seq_start,
1136 .next = dyn_event_seq_next,
1137 .stop = dyn_event_seq_stop,
1138 .show = probes_seq_show
1139};
1140
1141static int probes_open(struct inode *inode, struct file *file)
1142{
1143 int ret;
1144
1145 ret = security_locked_down(LOCKDOWN_TRACEFS);
1146 if (ret)
1147 return ret;
1148
1149 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1150 ret = dyn_events_release_all(&trace_kprobe_ops);
1151 if (ret < 0)
1152 return ret;
1153 }
1154
1155 return seq_open(file, &probes_seq_op);
1156}
1157
1158static ssize_t probes_write(struct file *file, const char __user *buffer,
1159 size_t count, loff_t *ppos)
1160{
1161 return trace_parse_run_command(file, buffer, count, ppos,
1162 create_or_delete_trace_kprobe);
1163}
1164
1165static const struct file_operations kprobe_events_ops = {
1166 .owner = THIS_MODULE,
1167 .open = probes_open,
1168 .read = seq_read,
1169 .llseek = seq_lseek,
1170 .release = seq_release,
1171 .write = probes_write,
1172};
1173
1174/* Probes profiling interfaces */
1175static int probes_profile_seq_show(struct seq_file *m, void *v)
1176{
1177 struct dyn_event *ev = v;
1178 struct trace_kprobe *tk;
1179 unsigned long nmissed;
1180
1181 if (!is_trace_kprobe(ev))
1182 return 0;
1183
1184 tk = to_trace_kprobe(ev);
1185 nmissed = trace_kprobe_is_return(tk) ?
1186 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
1187 seq_printf(m, " %-44s %15lu %15lu\n",
1188 trace_probe_name(&tk->tp),
1189 trace_kprobe_nhit(tk),
1190 nmissed);
1191
1192 return 0;
1193}
1194
1195static const struct seq_operations profile_seq_op = {
1196 .start = dyn_event_seq_start,
1197 .next = dyn_event_seq_next,
1198 .stop = dyn_event_seq_stop,
1199 .show = probes_profile_seq_show
1200};
1201
1202static int profile_open(struct inode *inode, struct file *file)
1203{
1204 int ret;
1205
1206 ret = security_locked_down(LOCKDOWN_TRACEFS);
1207 if (ret)
1208 return ret;
1209
1210 return seq_open(file, &profile_seq_op);
1211}
1212
1213static const struct file_operations kprobe_profile_ops = {
1214 .owner = THIS_MODULE,
1215 .open = profile_open,
1216 .read = seq_read,
1217 .llseek = seq_lseek,
1218 .release = seq_release,
1219};
1220
1221/* Kprobe specific fetch functions */
1222
1223/* Return the length of string -- including null terminal byte */
1224static nokprobe_inline int
1225fetch_store_strlen_user(unsigned long addr)
1226{
1227 return kern_fetch_store_strlen_user(addr);
1228}
1229
1230/* Return the length of string -- including null terminal byte */
1231static nokprobe_inline int
1232fetch_store_strlen(unsigned long addr)
1233{
1234 return kern_fetch_store_strlen(addr);
1235}
1236
1237/*
1238 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
1239 * with max length and relative data location.
1240 */
1241static nokprobe_inline int
1242fetch_store_string_user(unsigned long addr, void *dest, void *base)
1243{
1244 return kern_fetch_store_string_user(addr, dest, base);
1245}
1246
1247/*
1248 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
1249 * length and relative data location.
1250 */
1251static nokprobe_inline int
1252fetch_store_string(unsigned long addr, void *dest, void *base)
1253{
1254 return kern_fetch_store_string(addr, dest, base);
1255}
1256
1257static nokprobe_inline int
1258probe_mem_read_user(void *dest, void *src, size_t size)
1259{
1260 const void __user *uaddr = (__force const void __user *)src;
1261
1262 return copy_from_user_nofault(dest, uaddr, size);
1263}
1264
1265static nokprobe_inline int
1266probe_mem_read(void *dest, void *src, size_t size)
1267{
1268#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1269 if ((unsigned long)src < TASK_SIZE)
1270 return probe_mem_read_user(dest, src, size);
1271#endif
1272 return copy_from_kernel_nofault(dest, src, size);
1273}
1274
1275/* Note that we don't verify it, since the code does not come from user space */
1276static int
1277process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
1278 void *base)
1279{
1280 struct pt_regs *regs = rec;
1281 unsigned long val;
1282
1283retry:
1284 /* 1st stage: get value from context */
1285 switch (code->op) {
1286 case FETCH_OP_REG:
1287 val = regs_get_register(regs, code->param);
1288 break;
1289 case FETCH_OP_STACK:
1290 val = regs_get_kernel_stack_nth(regs, code->param);
1291 break;
1292 case FETCH_OP_STACKP:
1293 val = kernel_stack_pointer(regs);
1294 break;
1295 case FETCH_OP_RETVAL:
1296 val = regs_return_value(regs);
1297 break;
1298 case FETCH_OP_IMM:
1299 val = code->immediate;
1300 break;
1301 case FETCH_OP_COMM:
1302 val = (unsigned long)current->comm;
1303 break;
1304 case FETCH_OP_DATA:
1305 val = (unsigned long)code->data;
1306 break;
1307#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1308 case FETCH_OP_ARG:
1309 val = regs_get_kernel_argument(regs, code->param);
1310 break;
1311#endif
1312 case FETCH_NOP_SYMBOL: /* Ignore a place holder */
1313 code++;
1314 goto retry;
1315 default:
1316 return -EILSEQ;
1317 }
1318 code++;
1319
1320 return process_fetch_insn_bottom(code, val, dest, base);
1321}
1322NOKPROBE_SYMBOL(process_fetch_insn)
1323
1324/* Kprobe handler */
1325static nokprobe_inline void
1326__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1327 struct trace_event_file *trace_file)
1328{
1329 struct kprobe_trace_entry_head *entry;
1330 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1331 struct trace_event_buffer fbuffer;
1332 int dsize;
1333
1334 WARN_ON(call != trace_file->event_call);
1335
1336 if (trace_trigger_soft_disabled(trace_file))
1337 return;
1338
1339 dsize = __get_data_size(&tk->tp, regs);
1340
1341 entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1342 sizeof(*entry) + tk->tp.size + dsize);
1343 if (!entry)
1344 return;
1345
1346 fbuffer.regs = regs;
1347 entry->ip = (unsigned long)tk->rp.kp.addr;
1348 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1349
1350 trace_event_buffer_commit(&fbuffer);
1351}
1352
1353static void
1354kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1355{
1356 struct event_file_link *link;
1357
1358 trace_probe_for_each_link_rcu(link, &tk->tp)
1359 __kprobe_trace_func(tk, regs, link->file);
1360}
1361NOKPROBE_SYMBOL(kprobe_trace_func);
1362
1363/* Kretprobe handler */
1364static nokprobe_inline void
1365__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1366 struct pt_regs *regs,
1367 struct trace_event_file *trace_file)
1368{
1369 struct kretprobe_trace_entry_head *entry;
1370 struct trace_event_buffer fbuffer;
1371 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1372 int dsize;
1373
1374 WARN_ON(call != trace_file->event_call);
1375
1376 if (trace_trigger_soft_disabled(trace_file))
1377 return;
1378
1379 dsize = __get_data_size(&tk->tp, regs);
1380
1381 entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1382 sizeof(*entry) + tk->tp.size + dsize);
1383 if (!entry)
1384 return;
1385
1386 fbuffer.regs = regs;
1387 entry->func = (unsigned long)tk->rp.kp.addr;
1388 entry->ret_ip = get_kretprobe_retaddr(ri);
1389 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1390
1391 trace_event_buffer_commit(&fbuffer);
1392}
1393
1394static void
1395kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1396 struct pt_regs *regs)
1397{
1398 struct event_file_link *link;
1399
1400 trace_probe_for_each_link_rcu(link, &tk->tp)
1401 __kretprobe_trace_func(tk, ri, regs, link->file);
1402}
1403NOKPROBE_SYMBOL(kretprobe_trace_func);
1404
1405/* Event entry printers */
1406static enum print_line_t
1407print_kprobe_event(struct trace_iterator *iter, int flags,
1408 struct trace_event *event)
1409{
1410 struct kprobe_trace_entry_head *field;
1411 struct trace_seq *s = &iter->seq;
1412 struct trace_probe *tp;
1413
1414 field = (struct kprobe_trace_entry_head *)iter->ent;
1415 tp = trace_probe_primary_from_call(
1416 container_of(event, struct trace_event_call, event));
1417 if (WARN_ON_ONCE(!tp))
1418 goto out;
1419
1420 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1421
1422 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1423 goto out;
1424
1425 trace_seq_putc(s, ')');
1426
1427 if (print_probe_args(s, tp->args, tp->nr_args,
1428 (u8 *)&field[1], field) < 0)
1429 goto out;
1430
1431 trace_seq_putc(s, '\n');
1432 out:
1433 return trace_handle_return(s);
1434}
1435
1436static enum print_line_t
1437print_kretprobe_event(struct trace_iterator *iter, int flags,
1438 struct trace_event *event)
1439{
1440 struct kretprobe_trace_entry_head *field;
1441 struct trace_seq *s = &iter->seq;
1442 struct trace_probe *tp;
1443
1444 field = (struct kretprobe_trace_entry_head *)iter->ent;
1445 tp = trace_probe_primary_from_call(
1446 container_of(event, struct trace_event_call, event));
1447 if (WARN_ON_ONCE(!tp))
1448 goto out;
1449
1450 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1451
1452 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1453 goto out;
1454
1455 trace_seq_puts(s, " <- ");
1456
1457 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1458 goto out;
1459
1460 trace_seq_putc(s, ')');
1461
1462 if (print_probe_args(s, tp->args, tp->nr_args,
1463 (u8 *)&field[1], field) < 0)
1464 goto out;
1465
1466 trace_seq_putc(s, '\n');
1467
1468 out:
1469 return trace_handle_return(s);
1470}
1471
1472
1473static int kprobe_event_define_fields(struct trace_event_call *event_call)
1474{
1475 int ret;
1476 struct kprobe_trace_entry_head field;
1477 struct trace_probe *tp;
1478
1479 tp = trace_probe_primary_from_call(event_call);
1480 if (WARN_ON_ONCE(!tp))
1481 return -ENOENT;
1482
1483 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1484
1485 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1486}
1487
1488static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1489{
1490 int ret;
1491 struct kretprobe_trace_entry_head field;
1492 struct trace_probe *tp;
1493
1494 tp = trace_probe_primary_from_call(event_call);
1495 if (WARN_ON_ONCE(!tp))
1496 return -ENOENT;
1497
1498 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1499 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1500
1501 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1502}
1503
1504#ifdef CONFIG_PERF_EVENTS
1505
1506/* Kprobe profile handler */
1507static int
1508kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1509{
1510 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1511 struct kprobe_trace_entry_head *entry;
1512 struct hlist_head *head;
1513 int size, __size, dsize;
1514 int rctx;
1515
1516 if (bpf_prog_array_valid(call)) {
1517 unsigned long orig_ip = instruction_pointer(regs);
1518 int ret;
1519
1520 ret = trace_call_bpf(call, regs);
1521
1522 /*
1523 * We need to check and see if we modified the pc of the
1524 * pt_regs, and if so return 1 so that we don't do the
1525 * single stepping.
1526 */
1527 if (orig_ip != instruction_pointer(regs))
1528 return 1;
1529 if (!ret)
1530 return 0;
1531 }
1532
1533 head = this_cpu_ptr(call->perf_events);
1534 if (hlist_empty(head))
1535 return 0;
1536
1537 dsize = __get_data_size(&tk->tp, regs);
1538 __size = sizeof(*entry) + tk->tp.size + dsize;
1539 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1540 size -= sizeof(u32);
1541
1542 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1543 if (!entry)
1544 return 0;
1545
1546 entry->ip = (unsigned long)tk->rp.kp.addr;
1547 memset(&entry[1], 0, dsize);
1548 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1549 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1550 head, NULL);
1551 return 0;
1552}
1553NOKPROBE_SYMBOL(kprobe_perf_func);
1554
1555/* Kretprobe profile handler */
1556static void
1557kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1558 struct pt_regs *regs)
1559{
1560 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1561 struct kretprobe_trace_entry_head *entry;
1562 struct hlist_head *head;
1563 int size, __size, dsize;
1564 int rctx;
1565
1566 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1567 return;
1568
1569 head = this_cpu_ptr(call->perf_events);
1570 if (hlist_empty(head))
1571 return;
1572
1573 dsize = __get_data_size(&tk->tp, regs);
1574 __size = sizeof(*entry) + tk->tp.size + dsize;
1575 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1576 size -= sizeof(u32);
1577
1578 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1579 if (!entry)
1580 return;
1581
1582 entry->func = (unsigned long)tk->rp.kp.addr;
1583 entry->ret_ip = get_kretprobe_retaddr(ri);
1584 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1585 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1586 head, NULL);
1587}
1588NOKPROBE_SYMBOL(kretprobe_perf_func);
1589
1590int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1591 const char **symbol, u64 *probe_offset,
1592 u64 *probe_addr, bool perf_type_tracepoint)
1593{
1594 const char *pevent = trace_event_name(event->tp_event);
1595 const char *group = event->tp_event->class->system;
1596 struct trace_kprobe *tk;
1597
1598 if (perf_type_tracepoint)
1599 tk = find_trace_kprobe(pevent, group);
1600 else
1601 tk = trace_kprobe_primary_from_call(event->tp_event);
1602 if (!tk)
1603 return -EINVAL;
1604
1605 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1606 : BPF_FD_TYPE_KPROBE;
1607 if (tk->symbol) {
1608 *symbol = tk->symbol;
1609 *probe_offset = tk->rp.kp.offset;
1610 *probe_addr = 0;
1611 } else {
1612 *symbol = NULL;
1613 *probe_offset = 0;
1614 *probe_addr = (unsigned long)tk->rp.kp.addr;
1615 }
1616 return 0;
1617}
1618#endif /* CONFIG_PERF_EVENTS */
1619
1620/*
1621 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1622 *
1623 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1624 * lockless, but we can't race with this __init function.
1625 */
1626static int kprobe_register(struct trace_event_call *event,
1627 enum trace_reg type, void *data)
1628{
1629 struct trace_event_file *file = data;
1630
1631 switch (type) {
1632 case TRACE_REG_REGISTER:
1633 return enable_trace_kprobe(event, file);
1634 case TRACE_REG_UNREGISTER:
1635 return disable_trace_kprobe(event, file);
1636
1637#ifdef CONFIG_PERF_EVENTS
1638 case TRACE_REG_PERF_REGISTER:
1639 return enable_trace_kprobe(event, NULL);
1640 case TRACE_REG_PERF_UNREGISTER:
1641 return disable_trace_kprobe(event, NULL);
1642 case TRACE_REG_PERF_OPEN:
1643 case TRACE_REG_PERF_CLOSE:
1644 case TRACE_REG_PERF_ADD:
1645 case TRACE_REG_PERF_DEL:
1646 return 0;
1647#endif
1648 }
1649 return 0;
1650}
1651
1652static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1653{
1654 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1655 int ret = 0;
1656
1657 raw_cpu_inc(*tk->nhit);
1658
1659 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1660 kprobe_trace_func(tk, regs);
1661#ifdef CONFIG_PERF_EVENTS
1662 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1663 ret = kprobe_perf_func(tk, regs);
1664#endif
1665 return ret;
1666}
1667NOKPROBE_SYMBOL(kprobe_dispatcher);
1668
1669static int
1670kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1671{
1672 struct kretprobe *rp = get_kretprobe(ri);
1673 struct trace_kprobe *tk;
1674
1675 /*
1676 * There is a small chance that get_kretprobe(ri) returns NULL when
1677 * the kretprobe is unregister on another CPU between kretprobe's
1678 * trampoline_handler and this function.
1679 */
1680 if (unlikely(!rp))
1681 return 0;
1682
1683 tk = container_of(rp, struct trace_kprobe, rp);
1684 raw_cpu_inc(*tk->nhit);
1685
1686 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1687 kretprobe_trace_func(tk, ri, regs);
1688#ifdef CONFIG_PERF_EVENTS
1689 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1690 kretprobe_perf_func(tk, ri, regs);
1691#endif
1692 return 0; /* We don't tweak kernel, so just return 0 */
1693}
1694NOKPROBE_SYMBOL(kretprobe_dispatcher);
1695
1696static struct trace_event_functions kretprobe_funcs = {
1697 .trace = print_kretprobe_event
1698};
1699
1700static struct trace_event_functions kprobe_funcs = {
1701 .trace = print_kprobe_event
1702};
1703
1704static struct trace_event_fields kretprobe_fields_array[] = {
1705 { .type = TRACE_FUNCTION_TYPE,
1706 .define_fields = kretprobe_event_define_fields },
1707 {}
1708};
1709
1710static struct trace_event_fields kprobe_fields_array[] = {
1711 { .type = TRACE_FUNCTION_TYPE,
1712 .define_fields = kprobe_event_define_fields },
1713 {}
1714};
1715
1716static inline void init_trace_event_call(struct trace_kprobe *tk)
1717{
1718 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1719
1720 if (trace_kprobe_is_return(tk)) {
1721 call->event.funcs = &kretprobe_funcs;
1722 call->class->fields_array = kretprobe_fields_array;
1723 } else {
1724 call->event.funcs = &kprobe_funcs;
1725 call->class->fields_array = kprobe_fields_array;
1726 }
1727
1728 call->flags = TRACE_EVENT_FL_KPROBE;
1729 call->class->reg = kprobe_register;
1730}
1731
1732static int register_kprobe_event(struct trace_kprobe *tk)
1733{
1734 init_trace_event_call(tk);
1735
1736 return trace_probe_register_event_call(&tk->tp);
1737}
1738
1739static int unregister_kprobe_event(struct trace_kprobe *tk)
1740{
1741 return trace_probe_unregister_event_call(&tk->tp);
1742}
1743
1744#ifdef CONFIG_PERF_EVENTS
1745/* create a trace_kprobe, but don't add it to global lists */
1746struct trace_event_call *
1747create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1748 bool is_return)
1749{
1750 enum probe_print_type ptype;
1751 struct trace_kprobe *tk;
1752 int ret;
1753 char *event;
1754
1755 /*
1756 * local trace_kprobes are not added to dyn_event, so they are never
1757 * searched in find_trace_kprobe(). Therefore, there is no concern of
1758 * duplicated name here.
1759 */
1760 event = func ? func : "DUMMY_EVENT";
1761
1762 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1763 offs, 0 /* maxactive */, 0 /* nargs */,
1764 is_return);
1765
1766 if (IS_ERR(tk)) {
1767 pr_info("Failed to allocate trace_probe.(%d)\n",
1768 (int)PTR_ERR(tk));
1769 return ERR_CAST(tk);
1770 }
1771
1772 init_trace_event_call(tk);
1773
1774 ptype = trace_kprobe_is_return(tk) ?
1775 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1776 if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) {
1777 ret = -ENOMEM;
1778 goto error;
1779 }
1780
1781 ret = __register_trace_kprobe(tk);
1782 if (ret < 0)
1783 goto error;
1784
1785 return trace_probe_event_call(&tk->tp);
1786error:
1787 free_trace_kprobe(tk);
1788 return ERR_PTR(ret);
1789}
1790
1791void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1792{
1793 struct trace_kprobe *tk;
1794
1795 tk = trace_kprobe_primary_from_call(event_call);
1796 if (unlikely(!tk))
1797 return;
1798
1799 if (trace_probe_is_enabled(&tk->tp)) {
1800 WARN_ON(1);
1801 return;
1802 }
1803
1804 __unregister_trace_kprobe(tk);
1805
1806 free_trace_kprobe(tk);
1807}
1808#endif /* CONFIG_PERF_EVENTS */
1809
1810static __init void enable_boot_kprobe_events(void)
1811{
1812 struct trace_array *tr = top_trace_array();
1813 struct trace_event_file *file;
1814 struct trace_kprobe *tk;
1815 struct dyn_event *pos;
1816
1817 mutex_lock(&event_mutex);
1818 for_each_trace_kprobe(tk, pos) {
1819 list_for_each_entry(file, &tr->events, list)
1820 if (file->event_call == trace_probe_event_call(&tk->tp))
1821 trace_event_enable_disable(file, 1, 0);
1822 }
1823 mutex_unlock(&event_mutex);
1824}
1825
1826static __init void setup_boot_kprobe_events(void)
1827{
1828 char *p, *cmd = kprobe_boot_events_buf;
1829 int ret;
1830
1831 strreplace(kprobe_boot_events_buf, ',', ' ');
1832
1833 while (cmd && *cmd != '\0') {
1834 p = strchr(cmd, ';');
1835 if (p)
1836 *p++ = '\0';
1837
1838 ret = create_or_delete_trace_kprobe(cmd);
1839 if (ret)
1840 pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1841
1842 cmd = p;
1843 }
1844
1845 enable_boot_kprobe_events();
1846}
1847
1848/*
1849 * Register dynevent at core_initcall. This allows kernel to setup kprobe
1850 * events in postcore_initcall without tracefs.
1851 */
1852static __init int init_kprobe_trace_early(void)
1853{
1854 int ret;
1855
1856 ret = dyn_event_register(&trace_kprobe_ops);
1857 if (ret)
1858 return ret;
1859
1860 if (register_module_notifier(&trace_kprobe_module_nb))
1861 return -EINVAL;
1862
1863 return 0;
1864}
1865core_initcall(init_kprobe_trace_early);
1866
1867/* Make a tracefs interface for controlling probe points */
1868static __init int init_kprobe_trace(void)
1869{
1870 int ret;
1871
1872 ret = tracing_init_dentry();
1873 if (ret)
1874 return 0;
1875
1876 /* Event list interface */
1877 trace_create_file("kprobe_events", TRACE_MODE_WRITE,
1878 NULL, NULL, &kprobe_events_ops);
1879
1880 /* Profile interface */
1881 trace_create_file("kprobe_profile", TRACE_MODE_READ,
1882 NULL, NULL, &kprobe_profile_ops);
1883
1884 setup_boot_kprobe_events();
1885
1886 return 0;
1887}
1888fs_initcall(init_kprobe_trace);
1889
1890
1891#ifdef CONFIG_FTRACE_STARTUP_TEST
1892static __init struct trace_event_file *
1893find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1894{
1895 struct trace_event_file *file;
1896
1897 list_for_each_entry(file, &tr->events, list)
1898 if (file->event_call == trace_probe_event_call(&tk->tp))
1899 return file;
1900
1901 return NULL;
1902}
1903
1904/*
1905 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1906 * stage, we can do this lockless.
1907 */
1908static __init int kprobe_trace_self_tests_init(void)
1909{
1910 int ret, warn = 0;
1911 int (*target)(int, int, int, int, int, int);
1912 struct trace_kprobe *tk;
1913 struct trace_event_file *file;
1914
1915 if (tracing_is_disabled())
1916 return -ENODEV;
1917
1918 if (tracing_selftest_disabled)
1919 return 0;
1920
1921 target = kprobe_trace_selftest_target;
1922
1923 pr_info("Testing kprobe tracing: ");
1924
1925 ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
1926 if (WARN_ON_ONCE(ret)) {
1927 pr_warn("error on probing function entry.\n");
1928 warn++;
1929 } else {
1930 /* Enable trace point */
1931 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1932 if (WARN_ON_ONCE(tk == NULL)) {
1933 pr_warn("error on getting new probe.\n");
1934 warn++;
1935 } else {
1936 file = find_trace_probe_file(tk, top_trace_array());
1937 if (WARN_ON_ONCE(file == NULL)) {
1938 pr_warn("error on getting probe file.\n");
1939 warn++;
1940 } else
1941 enable_trace_kprobe(
1942 trace_probe_event_call(&tk->tp), file);
1943 }
1944 }
1945
1946 ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
1947 if (WARN_ON_ONCE(ret)) {
1948 pr_warn("error on probing function return.\n");
1949 warn++;
1950 } else {
1951 /* Enable trace point */
1952 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1953 if (WARN_ON_ONCE(tk == NULL)) {
1954 pr_warn("error on getting 2nd new probe.\n");
1955 warn++;
1956 } else {
1957 file = find_trace_probe_file(tk, top_trace_array());
1958 if (WARN_ON_ONCE(file == NULL)) {
1959 pr_warn("error on getting probe file.\n");
1960 warn++;
1961 } else
1962 enable_trace_kprobe(
1963 trace_probe_event_call(&tk->tp), file);
1964 }
1965 }
1966
1967 if (warn)
1968 goto end;
1969
1970 ret = target(1, 2, 3, 4, 5, 6);
1971
1972 /*
1973 * Not expecting an error here, the check is only to prevent the
1974 * optimizer from removing the call to target() as otherwise there
1975 * are no side-effects and the call is never performed.
1976 */
1977 if (ret != 21)
1978 warn++;
1979
1980 /* Disable trace points before removing it */
1981 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1982 if (WARN_ON_ONCE(tk == NULL)) {
1983 pr_warn("error on getting test probe.\n");
1984 warn++;
1985 } else {
1986 if (trace_kprobe_nhit(tk) != 1) {
1987 pr_warn("incorrect number of testprobe hits\n");
1988 warn++;
1989 }
1990
1991 file = find_trace_probe_file(tk, top_trace_array());
1992 if (WARN_ON_ONCE(file == NULL)) {
1993 pr_warn("error on getting probe file.\n");
1994 warn++;
1995 } else
1996 disable_trace_kprobe(
1997 trace_probe_event_call(&tk->tp), file);
1998 }
1999
2000 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2001 if (WARN_ON_ONCE(tk == NULL)) {
2002 pr_warn("error on getting 2nd test probe.\n");
2003 warn++;
2004 } else {
2005 if (trace_kprobe_nhit(tk) != 1) {
2006 pr_warn("incorrect number of testprobe2 hits\n");
2007 warn++;
2008 }
2009
2010 file = find_trace_probe_file(tk, top_trace_array());
2011 if (WARN_ON_ONCE(file == NULL)) {
2012 pr_warn("error on getting probe file.\n");
2013 warn++;
2014 } else
2015 disable_trace_kprobe(
2016 trace_probe_event_call(&tk->tp), file);
2017 }
2018
2019 ret = create_or_delete_trace_kprobe("-:testprobe");
2020 if (WARN_ON_ONCE(ret)) {
2021 pr_warn("error on deleting a probe.\n");
2022 warn++;
2023 }
2024
2025 ret = create_or_delete_trace_kprobe("-:testprobe2");
2026 if (WARN_ON_ONCE(ret)) {
2027 pr_warn("error on deleting a probe.\n");
2028 warn++;
2029 }
2030
2031end:
2032 ret = dyn_events_release_all(&trace_kprobe_ops);
2033 if (WARN_ON_ONCE(ret)) {
2034 pr_warn("error on cleaning up probes.\n");
2035 warn++;
2036 }
2037 /*
2038 * Wait for the optimizer work to finish. Otherwise it might fiddle
2039 * with probes in already freed __init text.
2040 */
2041 wait_for_kprobe_optimizer();
2042 if (warn)
2043 pr_cont("NG: Some tests are failed. Please check them.\n");
2044 else
2045 pr_cont("OK\n");
2046 return 0;
2047}
2048
2049late_initcall(kprobe_trace_self_tests_init);
2050
2051#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/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
26/* Kprobe early definition from command line */
27static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
28
29static int __init set_kprobe_boot_events(char *str)
30{
31 strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
32 disable_tracing_selftest("running kprobe events");
33
34 return 0;
35}
36__setup("kprobe_event=", set_kprobe_boot_events);
37
38static int trace_kprobe_create(const char *raw_command);
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(module_name(mod));
111 const char *name = trace_kprobe_symbol(tk);
112
113 return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
114}
115
116static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
117{
118 char *p;
119 bool ret;
120
121 if (!tk->symbol)
122 return false;
123 p = strchr(tk->symbol, ':');
124 if (!p)
125 return true;
126 *p = '\0';
127 rcu_read_lock_sched();
128 ret = !!find_module(tk->symbol);
129 rcu_read_unlock_sched();
130 *p = ':';
131
132 return ret;
133}
134
135static bool trace_kprobe_is_busy(struct dyn_event *ev)
136{
137 struct trace_kprobe *tk = to_trace_kprobe(ev);
138
139 return trace_probe_is_enabled(&tk->tp);
140}
141
142static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
143 int argc, const char **argv)
144{
145 char buf[MAX_ARGSTR_LEN + 1];
146
147 if (!argc)
148 return true;
149
150 if (!tk->symbol)
151 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
152 else if (tk->rp.kp.offset)
153 snprintf(buf, sizeof(buf), "%s+%u",
154 trace_kprobe_symbol(tk), tk->rp.kp.offset);
155 else
156 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
157 if (strcmp(buf, argv[0]))
158 return false;
159 argc--; argv++;
160
161 return trace_probe_match_command_args(&tk->tp, argc, argv);
162}
163
164static bool trace_kprobe_match(const char *system, const char *event,
165 int argc, const char **argv, struct dyn_event *ev)
166{
167 struct trace_kprobe *tk = to_trace_kprobe(ev);
168
169 return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
170 (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
171 trace_kprobe_match_command_head(tk, argc, argv);
172}
173
174static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
175{
176 unsigned long nhit = 0;
177 int cpu;
178
179 for_each_possible_cpu(cpu)
180 nhit += *per_cpu_ptr(tk->nhit, cpu);
181
182 return nhit;
183}
184
185static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
186{
187 return !(list_empty(&tk->rp.kp.list) &&
188 hlist_unhashed(&tk->rp.kp.hlist));
189}
190
191/* Return 0 if it fails to find the symbol address */
192static nokprobe_inline
193unsigned long trace_kprobe_address(struct trace_kprobe *tk)
194{
195 unsigned long addr;
196
197 if (tk->symbol) {
198 addr = (unsigned long)
199 kallsyms_lookup_name(trace_kprobe_symbol(tk));
200 if (addr)
201 addr += tk->rp.kp.offset;
202 } else {
203 addr = (unsigned long)tk->rp.kp.addr;
204 }
205 return addr;
206}
207
208static nokprobe_inline struct trace_kprobe *
209trace_kprobe_primary_from_call(struct trace_event_call *call)
210{
211 struct trace_probe *tp;
212
213 tp = trace_probe_primary_from_call(call);
214 if (WARN_ON_ONCE(!tp))
215 return NULL;
216
217 return container_of(tp, struct trace_kprobe, tp);
218}
219
220bool trace_kprobe_on_func_entry(struct trace_event_call *call)
221{
222 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
223
224 return tk ? (kprobe_on_func_entry(tk->rp.kp.addr,
225 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
226 tk->rp.kp.addr ? 0 : tk->rp.kp.offset) == 0) : false;
227}
228
229bool trace_kprobe_error_injectable(struct trace_event_call *call)
230{
231 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
232
233 return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
234 false;
235}
236
237static int register_kprobe_event(struct trace_kprobe *tk);
238static int unregister_kprobe_event(struct trace_kprobe *tk);
239
240static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
241static int kretprobe_dispatcher(struct kretprobe_instance *ri,
242 struct pt_regs *regs);
243
244static void free_trace_kprobe(struct trace_kprobe *tk)
245{
246 if (tk) {
247 trace_probe_cleanup(&tk->tp);
248 kfree(tk->symbol);
249 free_percpu(tk->nhit);
250 kfree(tk);
251 }
252}
253
254/*
255 * Allocate new trace_probe and initialize it (including kprobes).
256 */
257static struct trace_kprobe *alloc_trace_kprobe(const char *group,
258 const char *event,
259 void *addr,
260 const char *symbol,
261 unsigned long offs,
262 int maxactive,
263 int nargs, bool is_return)
264{
265 struct trace_kprobe *tk;
266 int ret = -ENOMEM;
267
268 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
269 if (!tk)
270 return ERR_PTR(ret);
271
272 tk->nhit = alloc_percpu(unsigned long);
273 if (!tk->nhit)
274 goto error;
275
276 if (symbol) {
277 tk->symbol = kstrdup(symbol, GFP_KERNEL);
278 if (!tk->symbol)
279 goto error;
280 tk->rp.kp.symbol_name = tk->symbol;
281 tk->rp.kp.offset = offs;
282 } else
283 tk->rp.kp.addr = addr;
284
285 if (is_return)
286 tk->rp.handler = kretprobe_dispatcher;
287 else
288 tk->rp.kp.pre_handler = kprobe_dispatcher;
289
290 tk->rp.maxactive = maxactive;
291 INIT_HLIST_NODE(&tk->rp.kp.hlist);
292 INIT_LIST_HEAD(&tk->rp.kp.list);
293
294 ret = trace_probe_init(&tk->tp, event, group, false);
295 if (ret < 0)
296 goto error;
297
298 dyn_event_init(&tk->devent, &trace_kprobe_ops);
299 return tk;
300error:
301 free_trace_kprobe(tk);
302 return ERR_PTR(ret);
303}
304
305static struct trace_kprobe *find_trace_kprobe(const char *event,
306 const char *group)
307{
308 struct dyn_event *pos;
309 struct trace_kprobe *tk;
310
311 for_each_trace_kprobe(tk, pos)
312 if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
313 strcmp(trace_probe_group_name(&tk->tp), group) == 0)
314 return tk;
315 return NULL;
316}
317
318static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
319{
320 int ret = 0;
321
322 if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
323 if (trace_kprobe_is_return(tk))
324 ret = enable_kretprobe(&tk->rp);
325 else
326 ret = enable_kprobe(&tk->rp.kp);
327 }
328
329 return ret;
330}
331
332static void __disable_trace_kprobe(struct trace_probe *tp)
333{
334 struct trace_probe *pos;
335 struct trace_kprobe *tk;
336
337 list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
338 tk = container_of(pos, struct trace_kprobe, tp);
339 if (!trace_kprobe_is_registered(tk))
340 continue;
341 if (trace_kprobe_is_return(tk))
342 disable_kretprobe(&tk->rp);
343 else
344 disable_kprobe(&tk->rp.kp);
345 }
346}
347
348/*
349 * Enable trace_probe
350 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
351 */
352static int enable_trace_kprobe(struct trace_event_call *call,
353 struct trace_event_file *file)
354{
355 struct trace_probe *pos, *tp;
356 struct trace_kprobe *tk;
357 bool enabled;
358 int ret = 0;
359
360 tp = trace_probe_primary_from_call(call);
361 if (WARN_ON_ONCE(!tp))
362 return -ENODEV;
363 enabled = trace_probe_is_enabled(tp);
364
365 /* This also changes "enabled" state */
366 if (file) {
367 ret = trace_probe_add_file(tp, file);
368 if (ret)
369 return ret;
370 } else
371 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
372
373 if (enabled)
374 return 0;
375
376 list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
377 tk = container_of(pos, struct trace_kprobe, tp);
378 if (trace_kprobe_has_gone(tk))
379 continue;
380 ret = __enable_trace_kprobe(tk);
381 if (ret)
382 break;
383 enabled = true;
384 }
385
386 if (ret) {
387 /* Failed to enable one of them. Roll back all */
388 if (enabled)
389 __disable_trace_kprobe(tp);
390 if (file)
391 trace_probe_remove_file(tp, file);
392 else
393 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
394 }
395
396 return ret;
397}
398
399/*
400 * Disable trace_probe
401 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
402 */
403static int disable_trace_kprobe(struct trace_event_call *call,
404 struct trace_event_file *file)
405{
406 struct trace_probe *tp;
407
408 tp = trace_probe_primary_from_call(call);
409 if (WARN_ON_ONCE(!tp))
410 return -ENODEV;
411
412 if (file) {
413 if (!trace_probe_get_file_link(tp, file))
414 return -ENOENT;
415 if (!trace_probe_has_single_file(tp))
416 goto out;
417 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
418 } else
419 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
420
421 if (!trace_probe_is_enabled(tp))
422 __disable_trace_kprobe(tp);
423
424 out:
425 if (file)
426 /*
427 * Synchronization is done in below function. For perf event,
428 * file == NULL and perf_trace_event_unreg() calls
429 * tracepoint_synchronize_unregister() to ensure synchronize
430 * event. We don't need to care about it.
431 */
432 trace_probe_remove_file(tp, file);
433
434 return 0;
435}
436
437#if defined(CONFIG_DYNAMIC_FTRACE) && \
438 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
439static bool __within_notrace_func(unsigned long addr)
440{
441 unsigned long offset, size;
442
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
456static bool within_notrace_func(struct trace_kprobe *tk)
457{
458 unsigned long addr = trace_kprobe_address(tk);
459 char symname[KSYM_NAME_LEN], *p;
460
461 if (!__within_notrace_func(addr))
462 return false;
463
464 /* Check if the address is on a suffixed-symbol */
465 if (!lookup_symbol_name(addr, symname)) {
466 p = strchr(symname, '.');
467 if (!p)
468 return true;
469 *p = '\0';
470 addr = (unsigned long)kprobe_lookup_name(symname, 0);
471 if (addr)
472 return __within_notrace_func(addr);
473 }
474
475 return true;
476}
477#else
478#define within_notrace_func(tk) (false)
479#endif
480
481/* Internal register function - just handle k*probes and flags */
482static int __register_trace_kprobe(struct trace_kprobe *tk)
483{
484 int i, ret;
485
486 ret = security_locked_down(LOCKDOWN_KPROBES);
487 if (ret)
488 return ret;
489
490 if (trace_kprobe_is_registered(tk))
491 return -EINVAL;
492
493 if (within_notrace_func(tk)) {
494 pr_warn("Could not probe notrace function %s\n",
495 trace_kprobe_symbol(tk));
496 return -EINVAL;
497 }
498
499 for (i = 0; i < tk->tp.nr_args; i++) {
500 ret = traceprobe_update_arg(&tk->tp.args[i]);
501 if (ret)
502 return ret;
503 }
504
505 /* Set/clear disabled flag according to tp->flag */
506 if (trace_probe_is_enabled(&tk->tp))
507 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
508 else
509 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
510
511 if (trace_kprobe_is_return(tk))
512 ret = register_kretprobe(&tk->rp);
513 else
514 ret = register_kprobe(&tk->rp.kp);
515
516 return ret;
517}
518
519/* Internal unregister function - just handle k*probes and flags */
520static void __unregister_trace_kprobe(struct trace_kprobe *tk)
521{
522 if (trace_kprobe_is_registered(tk)) {
523 if (trace_kprobe_is_return(tk))
524 unregister_kretprobe(&tk->rp);
525 else
526 unregister_kprobe(&tk->rp.kp);
527 /* Cleanup kprobe for reuse and mark it unregistered */
528 INIT_HLIST_NODE(&tk->rp.kp.hlist);
529 INIT_LIST_HEAD(&tk->rp.kp.list);
530 if (tk->rp.kp.symbol_name)
531 tk->rp.kp.addr = NULL;
532 }
533}
534
535/* Unregister a trace_probe and probe_event */
536static int unregister_trace_kprobe(struct trace_kprobe *tk)
537{
538 /* If other probes are on the event, just unregister kprobe */
539 if (trace_probe_has_sibling(&tk->tp))
540 goto unreg;
541
542 /* Enabled event can not be unregistered */
543 if (trace_probe_is_enabled(&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 struct trace_probe *pos;
563 int i;
564
565 list_for_each_entry(pos, &tpe->probes, list) {
566 orig = container_of(pos, struct trace_kprobe, tp);
567 if (strcmp(trace_kprobe_symbol(orig),
568 trace_kprobe_symbol(comp)) ||
569 trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
570 continue;
571
572 /*
573 * trace_probe_compare_arg_type() ensured that nr_args and
574 * each argument name and type are same. Let's compare comm.
575 */
576 for (i = 0; i < orig->tp.nr_args; i++) {
577 if (strcmp(orig->tp.args[i].comm,
578 comp->tp.args[i].comm))
579 break;
580 }
581
582 if (i == orig->tp.nr_args)
583 return true;
584 }
585
586 return false;
587}
588
589static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
590{
591 int ret;
592
593 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
594 if (ret) {
595 /* Note that argument starts index = 2 */
596 trace_probe_log_set_index(ret + 1);
597 trace_probe_log_err(0, DIFF_ARG_TYPE);
598 return -EEXIST;
599 }
600 if (trace_kprobe_has_same_kprobe(to, tk)) {
601 trace_probe_log_set_index(0);
602 trace_probe_log_err(0, SAME_PROBE);
603 return -EEXIST;
604 }
605
606 /* Append to existing event */
607 ret = trace_probe_append(&tk->tp, &to->tp);
608 if (ret)
609 return ret;
610
611 /* Register k*probe */
612 ret = __register_trace_kprobe(tk);
613 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
614 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
615 ret = 0;
616 }
617
618 if (ret)
619 trace_probe_unlink(&tk->tp);
620 else
621 dyn_event_add(&tk->devent);
622
623 return ret;
624}
625
626/* Register a trace_probe and probe_event */
627static int register_trace_kprobe(struct trace_kprobe *tk)
628{
629 struct trace_kprobe *old_tk;
630 int ret;
631
632 mutex_lock(&event_mutex);
633
634 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
635 trace_probe_group_name(&tk->tp));
636 if (old_tk) {
637 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
638 trace_probe_log_set_index(0);
639 trace_probe_log_err(0, DIFF_PROBE_TYPE);
640 ret = -EEXIST;
641 } else {
642 ret = append_trace_kprobe(tk, old_tk);
643 }
644 goto end;
645 }
646
647 /* Register new event */
648 ret = register_kprobe_event(tk);
649 if (ret) {
650 if (ret == -EEXIST) {
651 trace_probe_log_set_index(0);
652 trace_probe_log_err(0, EVENT_EXIST);
653 } else
654 pr_warn("Failed to register probe event(%d)\n", ret);
655 goto end;
656 }
657
658 /* Register k*probe */
659 ret = __register_trace_kprobe(tk);
660 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
661 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
662 ret = 0;
663 }
664
665 if (ret < 0)
666 unregister_kprobe_event(tk);
667 else
668 dyn_event_add(&tk->devent);
669
670end:
671 mutex_unlock(&event_mutex);
672 return ret;
673}
674
675/* Module notifier call back, checking event on the module */
676static int trace_kprobe_module_callback(struct notifier_block *nb,
677 unsigned long val, void *data)
678{
679 struct module *mod = data;
680 struct dyn_event *pos;
681 struct trace_kprobe *tk;
682 int ret;
683
684 if (val != MODULE_STATE_COMING)
685 return NOTIFY_DONE;
686
687 /* Update probes on coming module */
688 mutex_lock(&event_mutex);
689 for_each_trace_kprobe(tk, pos) {
690 if (trace_kprobe_within_module(tk, mod)) {
691 /* Don't need to check busy - this should have gone. */
692 __unregister_trace_kprobe(tk);
693 ret = __register_trace_kprobe(tk);
694 if (ret)
695 pr_warn("Failed to re-register probe %s on %s: %d\n",
696 trace_probe_name(&tk->tp),
697 module_name(mod), ret);
698 }
699 }
700 mutex_unlock(&event_mutex);
701
702 return NOTIFY_DONE;
703}
704
705static struct notifier_block trace_kprobe_module_nb = {
706 .notifier_call = trace_kprobe_module_callback,
707 .priority = 1 /* Invoked after kprobe module callback */
708};
709
710/* Convert certain expected symbols into '_' when generating event names */
711static inline void sanitize_event_name(char *name)
712{
713 while (*name++ != '\0')
714 if (*name == ':' || *name == '.')
715 *name = '_';
716}
717
718static int __trace_kprobe_create(int argc, const char *argv[])
719{
720 /*
721 * Argument syntax:
722 * - Add kprobe:
723 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
724 * - Add kretprobe:
725 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
726 * Or
727 * p:[GRP/]EVENT] [MOD:]KSYM[+0]%return [FETCHARGS]
728 *
729 * Fetch args:
730 * $retval : fetch return value
731 * $stack : fetch stack address
732 * $stackN : fetch Nth of stack (N:0-)
733 * $comm : fetch current task comm
734 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
735 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
736 * %REG : fetch register REG
737 * Dereferencing memory fetch:
738 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
739 * Alias name of args:
740 * NAME=FETCHARG : set NAME as alias of FETCHARG.
741 * Type of args:
742 * FETCHARG:TYPE : use TYPE instead of unsigned long.
743 */
744 struct trace_kprobe *tk = NULL;
745 int i, len, ret = 0;
746 bool is_return = false;
747 char *symbol = NULL, *tmp = NULL;
748 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
749 int maxactive = 0;
750 long offset = 0;
751 void *addr = NULL;
752 char buf[MAX_EVENT_NAME_LEN];
753 unsigned int flags = TPARG_FL_KERNEL;
754
755 switch (argv[0][0]) {
756 case 'r':
757 is_return = true;
758 break;
759 case 'p':
760 break;
761 default:
762 return -ECANCELED;
763 }
764 if (argc < 2)
765 return -ECANCELED;
766
767 trace_probe_log_init("trace_kprobe", argc, argv);
768
769 event = strchr(&argv[0][1], ':');
770 if (event)
771 event++;
772
773 if (isdigit(argv[0][1])) {
774 if (!is_return) {
775 trace_probe_log_err(1, MAXACT_NO_KPROBE);
776 goto parse_error;
777 }
778 if (event)
779 len = event - &argv[0][1] - 1;
780 else
781 len = strlen(&argv[0][1]);
782 if (len > MAX_EVENT_NAME_LEN - 1) {
783 trace_probe_log_err(1, BAD_MAXACT);
784 goto parse_error;
785 }
786 memcpy(buf, &argv[0][1], len);
787 buf[len] = '\0';
788 ret = kstrtouint(buf, 0, &maxactive);
789 if (ret || !maxactive) {
790 trace_probe_log_err(1, BAD_MAXACT);
791 goto parse_error;
792 }
793 /* kretprobes instances are iterated over via a list. The
794 * maximum should stay reasonable.
795 */
796 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
797 trace_probe_log_err(1, MAXACT_TOO_BIG);
798 goto parse_error;
799 }
800 }
801
802 /* try to parse an address. if that fails, try to read the
803 * input as a symbol. */
804 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
805 trace_probe_log_set_index(1);
806 /* Check whether uprobe event specified */
807 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
808 ret = -ECANCELED;
809 goto error;
810 }
811 /* a symbol specified */
812 symbol = kstrdup(argv[1], GFP_KERNEL);
813 if (!symbol)
814 return -ENOMEM;
815
816 tmp = strchr(symbol, '%');
817 if (tmp) {
818 if (!strcmp(tmp, "%return")) {
819 *tmp = '\0';
820 is_return = true;
821 } else {
822 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
823 goto parse_error;
824 }
825 }
826
827 /* TODO: support .init module functions */
828 ret = traceprobe_split_symbol_offset(symbol, &offset);
829 if (ret || offset < 0 || offset > UINT_MAX) {
830 trace_probe_log_err(0, BAD_PROBE_ADDR);
831 goto parse_error;
832 }
833 if (is_return)
834 flags |= TPARG_FL_RETURN;
835 ret = kprobe_on_func_entry(NULL, symbol, offset);
836 if (ret == 0)
837 flags |= TPARG_FL_FENTRY;
838 /* Defer the ENOENT case until register kprobe */
839 if (ret == -EINVAL && is_return) {
840 trace_probe_log_err(0, BAD_RETPROBE);
841 goto parse_error;
842 }
843 }
844
845 trace_probe_log_set_index(0);
846 if (event) {
847 ret = traceprobe_parse_event_name(&event, &group, buf,
848 event - argv[0]);
849 if (ret)
850 goto parse_error;
851 } else {
852 /* Make a new event name */
853 if (symbol)
854 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
855 is_return ? 'r' : 'p', symbol, offset);
856 else
857 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
858 is_return ? 'r' : 'p', addr);
859 sanitize_event_name(buf);
860 event = buf;
861 }
862
863 /* setup a probe */
864 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
865 argc - 2, is_return);
866 if (IS_ERR(tk)) {
867 ret = PTR_ERR(tk);
868 /* This must return -ENOMEM, else there is a bug */
869 WARN_ON_ONCE(ret != -ENOMEM);
870 goto out; /* We know tk is not allocated */
871 }
872 argc -= 2; argv += 2;
873
874 /* parse arguments */
875 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
876 tmp = kstrdup(argv[i], GFP_KERNEL);
877 if (!tmp) {
878 ret = -ENOMEM;
879 goto error;
880 }
881
882 trace_probe_log_set_index(i + 2);
883 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
884 kfree(tmp);
885 if (ret)
886 goto error; /* This can be -ENOMEM */
887 }
888
889 ret = traceprobe_set_print_fmt(&tk->tp, is_return);
890 if (ret < 0)
891 goto error;
892
893 ret = register_trace_kprobe(tk);
894 if (ret) {
895 trace_probe_log_set_index(1);
896 if (ret == -EILSEQ)
897 trace_probe_log_err(0, BAD_INSN_BNDRY);
898 else if (ret == -ENOENT)
899 trace_probe_log_err(0, BAD_PROBE_ADDR);
900 else if (ret != -ENOMEM && ret != -EEXIST)
901 trace_probe_log_err(0, FAIL_REG_PROBE);
902 goto error;
903 }
904
905out:
906 trace_probe_log_clear();
907 kfree(symbol);
908 return ret;
909
910parse_error:
911 ret = -EINVAL;
912error:
913 free_trace_kprobe(tk);
914 goto out;
915}
916
917static int trace_kprobe_create(const char *raw_command)
918{
919 return trace_probe_create(raw_command, __trace_kprobe_create);
920}
921
922static int create_or_delete_trace_kprobe(const char *raw_command)
923{
924 int ret;
925
926 if (raw_command[0] == '-')
927 return dyn_event_release(raw_command, &trace_kprobe_ops);
928
929 ret = trace_kprobe_create(raw_command);
930 return ret == -ECANCELED ? -EINVAL : ret;
931}
932
933static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
934{
935 return create_or_delete_trace_kprobe(cmd->seq.buffer);
936}
937
938/**
939 * kprobe_event_cmd_init - Initialize a kprobe event command object
940 * @cmd: A pointer to the dynevent_cmd struct representing the new event
941 * @buf: A pointer to the buffer used to build the command
942 * @maxlen: The length of the buffer passed in @buf
943 *
944 * Initialize a synthetic event command object. Use this before
945 * calling any of the other kprobe_event functions.
946 */
947void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
948{
949 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
950 trace_kprobe_run_command);
951}
952EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
953
954/**
955 * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
956 * @cmd: A pointer to the dynevent_cmd struct representing the new event
957 * @name: The name of the kprobe event
958 * @loc: The location of the kprobe event
959 * @kretprobe: Is this a return probe?
960 * @args: Variable number of arg (pairs), one pair for each field
961 *
962 * NOTE: Users normally won't want to call this function directly, but
963 * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
964 * adds a NULL to the end of the arg list. If this function is used
965 * directly, make sure the last arg in the variable arg list is NULL.
966 *
967 * Generate a kprobe event command to be executed by
968 * kprobe_event_gen_cmd_end(). This function can be used to generate the
969 * complete command or only the first part of it; in the latter case,
970 * kprobe_event_add_fields() can be used to add more fields following this.
971 *
972 * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
973 * returns -EINVAL if @loc == NULL.
974 *
975 * Return: 0 if successful, error otherwise.
976 */
977int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
978 const char *name, const char *loc, ...)
979{
980 char buf[MAX_EVENT_NAME_LEN];
981 struct dynevent_arg arg;
982 va_list args;
983 int ret;
984
985 if (cmd->type != DYNEVENT_TYPE_KPROBE)
986 return -EINVAL;
987
988 if (!loc)
989 return -EINVAL;
990
991 if (kretprobe)
992 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
993 else
994 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
995
996 ret = dynevent_str_add(cmd, buf);
997 if (ret)
998 return ret;
999
1000 dynevent_arg_init(&arg, 0);
1001 arg.str = loc;
1002 ret = dynevent_arg_add(cmd, &arg, NULL);
1003 if (ret)
1004 return ret;
1005
1006 va_start(args, loc);
1007 for (;;) {
1008 const char *field;
1009
1010 field = va_arg(args, const char *);
1011 if (!field)
1012 break;
1013
1014 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1015 ret = -EINVAL;
1016 break;
1017 }
1018
1019 arg.str = field;
1020 ret = dynevent_arg_add(cmd, &arg, NULL);
1021 if (ret)
1022 break;
1023 }
1024 va_end(args);
1025
1026 return ret;
1027}
1028EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1029
1030/**
1031 * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1032 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1033 * @args: Variable number of arg (pairs), one pair for each field
1034 *
1035 * NOTE: Users normally won't want to call this function directly, but
1036 * rather use the kprobe_event_add_fields() wrapper, which
1037 * automatically adds a NULL to the end of the arg list. If this
1038 * function is used directly, make sure the last arg in the variable
1039 * arg list is NULL.
1040 *
1041 * Add probe fields to an existing kprobe command using a variable
1042 * list of args. Fields are added in the same order they're listed.
1043 *
1044 * Return: 0 if successful, error otherwise.
1045 */
1046int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1047{
1048 struct dynevent_arg arg;
1049 va_list args;
1050 int ret = 0;
1051
1052 if (cmd->type != DYNEVENT_TYPE_KPROBE)
1053 return -EINVAL;
1054
1055 dynevent_arg_init(&arg, 0);
1056
1057 va_start(args, cmd);
1058 for (;;) {
1059 const char *field;
1060
1061 field = va_arg(args, const char *);
1062 if (!field)
1063 break;
1064
1065 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1066 ret = -EINVAL;
1067 break;
1068 }
1069
1070 arg.str = field;
1071 ret = dynevent_arg_add(cmd, &arg, NULL);
1072 if (ret)
1073 break;
1074 }
1075 va_end(args);
1076
1077 return ret;
1078}
1079EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1080
1081/**
1082 * kprobe_event_delete - Delete a kprobe event
1083 * @name: The name of the kprobe event to delete
1084 *
1085 * Delete a kprobe event with the give @name from kernel code rather
1086 * than directly from the command line.
1087 *
1088 * Return: 0 if successful, error otherwise.
1089 */
1090int kprobe_event_delete(const char *name)
1091{
1092 char buf[MAX_EVENT_NAME_LEN];
1093
1094 snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1095
1096 return create_or_delete_trace_kprobe(buf);
1097}
1098EXPORT_SYMBOL_GPL(kprobe_event_delete);
1099
1100static int trace_kprobe_release(struct dyn_event *ev)
1101{
1102 struct trace_kprobe *tk = to_trace_kprobe(ev);
1103 int ret = unregister_trace_kprobe(tk);
1104
1105 if (!ret)
1106 free_trace_kprobe(tk);
1107 return ret;
1108}
1109
1110static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1111{
1112 struct trace_kprobe *tk = to_trace_kprobe(ev);
1113 int i;
1114
1115 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1116 if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1117 seq_printf(m, "%d", tk->rp.maxactive);
1118 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1119 trace_probe_name(&tk->tp));
1120
1121 if (!tk->symbol)
1122 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1123 else if (tk->rp.kp.offset)
1124 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1125 tk->rp.kp.offset);
1126 else
1127 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1128
1129 for (i = 0; i < tk->tp.nr_args; i++)
1130 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1131 seq_putc(m, '\n');
1132
1133 return 0;
1134}
1135
1136static int probes_seq_show(struct seq_file *m, void *v)
1137{
1138 struct dyn_event *ev = v;
1139
1140 if (!is_trace_kprobe(ev))
1141 return 0;
1142
1143 return trace_kprobe_show(m, ev);
1144}
1145
1146static const struct seq_operations probes_seq_op = {
1147 .start = dyn_event_seq_start,
1148 .next = dyn_event_seq_next,
1149 .stop = dyn_event_seq_stop,
1150 .show = probes_seq_show
1151};
1152
1153static int probes_open(struct inode *inode, struct file *file)
1154{
1155 int ret;
1156
1157 ret = security_locked_down(LOCKDOWN_TRACEFS);
1158 if (ret)
1159 return ret;
1160
1161 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1162 ret = dyn_events_release_all(&trace_kprobe_ops);
1163 if (ret < 0)
1164 return ret;
1165 }
1166
1167 return seq_open(file, &probes_seq_op);
1168}
1169
1170static ssize_t probes_write(struct file *file, const char __user *buffer,
1171 size_t count, loff_t *ppos)
1172{
1173 return trace_parse_run_command(file, buffer, count, ppos,
1174 create_or_delete_trace_kprobe);
1175}
1176
1177static const struct file_operations kprobe_events_ops = {
1178 .owner = THIS_MODULE,
1179 .open = probes_open,
1180 .read = seq_read,
1181 .llseek = seq_lseek,
1182 .release = seq_release,
1183 .write = probes_write,
1184};
1185
1186/* Probes profiling interfaces */
1187static int probes_profile_seq_show(struct seq_file *m, void *v)
1188{
1189 struct dyn_event *ev = v;
1190 struct trace_kprobe *tk;
1191
1192 if (!is_trace_kprobe(ev))
1193 return 0;
1194
1195 tk = to_trace_kprobe(ev);
1196 seq_printf(m, " %-44s %15lu %15lu\n",
1197 trace_probe_name(&tk->tp),
1198 trace_kprobe_nhit(tk),
1199 tk->rp.kp.nmissed);
1200
1201 return 0;
1202}
1203
1204static const struct seq_operations profile_seq_op = {
1205 .start = dyn_event_seq_start,
1206 .next = dyn_event_seq_next,
1207 .stop = dyn_event_seq_stop,
1208 .show = probes_profile_seq_show
1209};
1210
1211static int profile_open(struct inode *inode, struct file *file)
1212{
1213 int ret;
1214
1215 ret = security_locked_down(LOCKDOWN_TRACEFS);
1216 if (ret)
1217 return ret;
1218
1219 return seq_open(file, &profile_seq_op);
1220}
1221
1222static const struct file_operations kprobe_profile_ops = {
1223 .owner = THIS_MODULE,
1224 .open = profile_open,
1225 .read = seq_read,
1226 .llseek = seq_lseek,
1227 .release = seq_release,
1228};
1229
1230/* Kprobe specific fetch functions */
1231
1232/* Return the length of string -- including null terminal byte */
1233static nokprobe_inline int
1234fetch_store_strlen_user(unsigned long addr)
1235{
1236 const void __user *uaddr = (__force const void __user *)addr;
1237
1238 return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
1239}
1240
1241/* Return the length of string -- including null terminal byte */
1242static nokprobe_inline int
1243fetch_store_strlen(unsigned long addr)
1244{
1245 int ret, len = 0;
1246 u8 c;
1247
1248#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1249 if (addr < TASK_SIZE)
1250 return fetch_store_strlen_user(addr);
1251#endif
1252
1253 do {
1254 ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);
1255 len++;
1256 } while (c && ret == 0 && len < MAX_STRING_SIZE);
1257
1258 return (ret < 0) ? ret : len;
1259}
1260
1261/*
1262 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
1263 * with max length and relative data location.
1264 */
1265static nokprobe_inline int
1266fetch_store_string_user(unsigned long addr, void *dest, void *base)
1267{
1268 const void __user *uaddr = (__force const void __user *)addr;
1269 int maxlen = get_loc_len(*(u32 *)dest);
1270 void *__dest;
1271 long ret;
1272
1273 if (unlikely(!maxlen))
1274 return -ENOMEM;
1275
1276 __dest = get_loc_data(dest, base);
1277
1278 ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
1279 if (ret >= 0)
1280 *(u32 *)dest = make_data_loc(ret, __dest - base);
1281
1282 return ret;
1283}
1284
1285/*
1286 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
1287 * length and relative data location.
1288 */
1289static nokprobe_inline int
1290fetch_store_string(unsigned long addr, void *dest, void *base)
1291{
1292 int maxlen = get_loc_len(*(u32 *)dest);
1293 void *__dest;
1294 long ret;
1295
1296#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1297 if ((unsigned long)addr < TASK_SIZE)
1298 return fetch_store_string_user(addr, dest, base);
1299#endif
1300
1301 if (unlikely(!maxlen))
1302 return -ENOMEM;
1303
1304 __dest = get_loc_data(dest, base);
1305
1306 /*
1307 * Try to get string again, since the string can be changed while
1308 * probing.
1309 */
1310 ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
1311 if (ret >= 0)
1312 *(u32 *)dest = make_data_loc(ret, __dest - base);
1313
1314 return ret;
1315}
1316
1317static nokprobe_inline int
1318probe_mem_read_user(void *dest, void *src, size_t size)
1319{
1320 const void __user *uaddr = (__force const void __user *)src;
1321
1322 return copy_from_user_nofault(dest, uaddr, size);
1323}
1324
1325static nokprobe_inline int
1326probe_mem_read(void *dest, void *src, size_t size)
1327{
1328#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1329 if ((unsigned long)src < TASK_SIZE)
1330 return probe_mem_read_user(dest, src, size);
1331#endif
1332 return copy_from_kernel_nofault(dest, src, size);
1333}
1334
1335/* Note that we don't verify it, since the code does not come from user space */
1336static int
1337process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
1338 void *base)
1339{
1340 unsigned long val;
1341
1342retry:
1343 /* 1st stage: get value from context */
1344 switch (code->op) {
1345 case FETCH_OP_REG:
1346 val = regs_get_register(regs, code->param);
1347 break;
1348 case FETCH_OP_STACK:
1349 val = regs_get_kernel_stack_nth(regs, code->param);
1350 break;
1351 case FETCH_OP_STACKP:
1352 val = kernel_stack_pointer(regs);
1353 break;
1354 case FETCH_OP_RETVAL:
1355 val = regs_return_value(regs);
1356 break;
1357 case FETCH_OP_IMM:
1358 val = code->immediate;
1359 break;
1360 case FETCH_OP_COMM:
1361 val = (unsigned long)current->comm;
1362 break;
1363 case FETCH_OP_DATA:
1364 val = (unsigned long)code->data;
1365 break;
1366#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1367 case FETCH_OP_ARG:
1368 val = regs_get_kernel_argument(regs, code->param);
1369 break;
1370#endif
1371 case FETCH_NOP_SYMBOL: /* Ignore a place holder */
1372 code++;
1373 goto retry;
1374 default:
1375 return -EILSEQ;
1376 }
1377 code++;
1378
1379 return process_fetch_insn_bottom(code, val, dest, base);
1380}
1381NOKPROBE_SYMBOL(process_fetch_insn)
1382
1383/* Kprobe handler */
1384static nokprobe_inline void
1385__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1386 struct trace_event_file *trace_file)
1387{
1388 struct kprobe_trace_entry_head *entry;
1389 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1390 struct trace_event_buffer fbuffer;
1391 int dsize;
1392
1393 WARN_ON(call != trace_file->event_call);
1394
1395 if (trace_trigger_soft_disabled(trace_file))
1396 return;
1397
1398 fbuffer.trace_ctx = tracing_gen_ctx();
1399 fbuffer.trace_file = trace_file;
1400
1401 dsize = __get_data_size(&tk->tp, regs);
1402
1403 fbuffer.event =
1404 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
1405 call->event.type,
1406 sizeof(*entry) + tk->tp.size + dsize,
1407 fbuffer.trace_ctx);
1408 if (!fbuffer.event)
1409 return;
1410
1411 fbuffer.regs = regs;
1412 entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
1413 entry->ip = (unsigned long)tk->rp.kp.addr;
1414 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1415
1416 trace_event_buffer_commit(&fbuffer);
1417}
1418
1419static void
1420kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1421{
1422 struct event_file_link *link;
1423
1424 trace_probe_for_each_link_rcu(link, &tk->tp)
1425 __kprobe_trace_func(tk, regs, link->file);
1426}
1427NOKPROBE_SYMBOL(kprobe_trace_func);
1428
1429/* Kretprobe handler */
1430static nokprobe_inline void
1431__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1432 struct pt_regs *regs,
1433 struct trace_event_file *trace_file)
1434{
1435 struct kretprobe_trace_entry_head *entry;
1436 struct trace_event_buffer fbuffer;
1437 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1438 int dsize;
1439
1440 WARN_ON(call != trace_file->event_call);
1441
1442 if (trace_trigger_soft_disabled(trace_file))
1443 return;
1444
1445 fbuffer.trace_ctx = tracing_gen_ctx();
1446 fbuffer.trace_file = trace_file;
1447
1448 dsize = __get_data_size(&tk->tp, regs);
1449 fbuffer.event =
1450 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
1451 call->event.type,
1452 sizeof(*entry) + tk->tp.size + dsize,
1453 fbuffer.trace_ctx);
1454 if (!fbuffer.event)
1455 return;
1456
1457 fbuffer.regs = regs;
1458 entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
1459 entry->func = (unsigned long)tk->rp.kp.addr;
1460 entry->ret_ip = (unsigned long)ri->ret_addr;
1461 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1462
1463 trace_event_buffer_commit(&fbuffer);
1464}
1465
1466static void
1467kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1468 struct pt_regs *regs)
1469{
1470 struct event_file_link *link;
1471
1472 trace_probe_for_each_link_rcu(link, &tk->tp)
1473 __kretprobe_trace_func(tk, ri, regs, link->file);
1474}
1475NOKPROBE_SYMBOL(kretprobe_trace_func);
1476
1477/* Event entry printers */
1478static enum print_line_t
1479print_kprobe_event(struct trace_iterator *iter, int flags,
1480 struct trace_event *event)
1481{
1482 struct kprobe_trace_entry_head *field;
1483 struct trace_seq *s = &iter->seq;
1484 struct trace_probe *tp;
1485
1486 field = (struct kprobe_trace_entry_head *)iter->ent;
1487 tp = trace_probe_primary_from_call(
1488 container_of(event, struct trace_event_call, event));
1489 if (WARN_ON_ONCE(!tp))
1490 goto out;
1491
1492 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1493
1494 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1495 goto out;
1496
1497 trace_seq_putc(s, ')');
1498
1499 if (print_probe_args(s, tp->args, tp->nr_args,
1500 (u8 *)&field[1], field) < 0)
1501 goto out;
1502
1503 trace_seq_putc(s, '\n');
1504 out:
1505 return trace_handle_return(s);
1506}
1507
1508static enum print_line_t
1509print_kretprobe_event(struct trace_iterator *iter, int flags,
1510 struct trace_event *event)
1511{
1512 struct kretprobe_trace_entry_head *field;
1513 struct trace_seq *s = &iter->seq;
1514 struct trace_probe *tp;
1515
1516 field = (struct kretprobe_trace_entry_head *)iter->ent;
1517 tp = trace_probe_primary_from_call(
1518 container_of(event, struct trace_event_call, event));
1519 if (WARN_ON_ONCE(!tp))
1520 goto out;
1521
1522 trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1523
1524 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1525 goto out;
1526
1527 trace_seq_puts(s, " <- ");
1528
1529 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1530 goto out;
1531
1532 trace_seq_putc(s, ')');
1533
1534 if (print_probe_args(s, tp->args, tp->nr_args,
1535 (u8 *)&field[1], field) < 0)
1536 goto out;
1537
1538 trace_seq_putc(s, '\n');
1539
1540 out:
1541 return trace_handle_return(s);
1542}
1543
1544
1545static int kprobe_event_define_fields(struct trace_event_call *event_call)
1546{
1547 int ret;
1548 struct kprobe_trace_entry_head field;
1549 struct trace_probe *tp;
1550
1551 tp = trace_probe_primary_from_call(event_call);
1552 if (WARN_ON_ONCE(!tp))
1553 return -ENOENT;
1554
1555 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1556
1557 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1558}
1559
1560static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1561{
1562 int ret;
1563 struct kretprobe_trace_entry_head field;
1564 struct trace_probe *tp;
1565
1566 tp = trace_probe_primary_from_call(event_call);
1567 if (WARN_ON_ONCE(!tp))
1568 return -ENOENT;
1569
1570 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1571 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1572
1573 return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1574}
1575
1576#ifdef CONFIG_PERF_EVENTS
1577
1578/* Kprobe profile handler */
1579static int
1580kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1581{
1582 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1583 struct kprobe_trace_entry_head *entry;
1584 struct hlist_head *head;
1585 int size, __size, dsize;
1586 int rctx;
1587
1588 if (bpf_prog_array_valid(call)) {
1589 unsigned long orig_ip = instruction_pointer(regs);
1590 int ret;
1591
1592 ret = trace_call_bpf(call, regs);
1593
1594 /*
1595 * We need to check and see if we modified the pc of the
1596 * pt_regs, and if so return 1 so that we don't do the
1597 * single stepping.
1598 */
1599 if (orig_ip != instruction_pointer(regs))
1600 return 1;
1601 if (!ret)
1602 return 0;
1603 }
1604
1605 head = this_cpu_ptr(call->perf_events);
1606 if (hlist_empty(head))
1607 return 0;
1608
1609 dsize = __get_data_size(&tk->tp, regs);
1610 __size = sizeof(*entry) + tk->tp.size + dsize;
1611 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1612 size -= sizeof(u32);
1613
1614 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1615 if (!entry)
1616 return 0;
1617
1618 entry->ip = (unsigned long)tk->rp.kp.addr;
1619 memset(&entry[1], 0, dsize);
1620 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1621 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1622 head, NULL);
1623 return 0;
1624}
1625NOKPROBE_SYMBOL(kprobe_perf_func);
1626
1627/* Kretprobe profile handler */
1628static void
1629kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1630 struct pt_regs *regs)
1631{
1632 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1633 struct kretprobe_trace_entry_head *entry;
1634 struct hlist_head *head;
1635 int size, __size, dsize;
1636 int rctx;
1637
1638 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1639 return;
1640
1641 head = this_cpu_ptr(call->perf_events);
1642 if (hlist_empty(head))
1643 return;
1644
1645 dsize = __get_data_size(&tk->tp, regs);
1646 __size = sizeof(*entry) + tk->tp.size + dsize;
1647 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1648 size -= sizeof(u32);
1649
1650 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1651 if (!entry)
1652 return;
1653
1654 entry->func = (unsigned long)tk->rp.kp.addr;
1655 entry->ret_ip = (unsigned long)ri->ret_addr;
1656 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1657 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1658 head, NULL);
1659}
1660NOKPROBE_SYMBOL(kretprobe_perf_func);
1661
1662int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1663 const char **symbol, u64 *probe_offset,
1664 u64 *probe_addr, bool perf_type_tracepoint)
1665{
1666 const char *pevent = trace_event_name(event->tp_event);
1667 const char *group = event->tp_event->class->system;
1668 struct trace_kprobe *tk;
1669
1670 if (perf_type_tracepoint)
1671 tk = find_trace_kprobe(pevent, group);
1672 else
1673 tk = trace_kprobe_primary_from_call(event->tp_event);
1674 if (!tk)
1675 return -EINVAL;
1676
1677 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1678 : BPF_FD_TYPE_KPROBE;
1679 if (tk->symbol) {
1680 *symbol = tk->symbol;
1681 *probe_offset = tk->rp.kp.offset;
1682 *probe_addr = 0;
1683 } else {
1684 *symbol = NULL;
1685 *probe_offset = 0;
1686 *probe_addr = (unsigned long)tk->rp.kp.addr;
1687 }
1688 return 0;
1689}
1690#endif /* CONFIG_PERF_EVENTS */
1691
1692/*
1693 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1694 *
1695 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1696 * lockless, but we can't race with this __init function.
1697 */
1698static int kprobe_register(struct trace_event_call *event,
1699 enum trace_reg type, void *data)
1700{
1701 struct trace_event_file *file = data;
1702
1703 switch (type) {
1704 case TRACE_REG_REGISTER:
1705 return enable_trace_kprobe(event, file);
1706 case TRACE_REG_UNREGISTER:
1707 return disable_trace_kprobe(event, file);
1708
1709#ifdef CONFIG_PERF_EVENTS
1710 case TRACE_REG_PERF_REGISTER:
1711 return enable_trace_kprobe(event, NULL);
1712 case TRACE_REG_PERF_UNREGISTER:
1713 return disable_trace_kprobe(event, NULL);
1714 case TRACE_REG_PERF_OPEN:
1715 case TRACE_REG_PERF_CLOSE:
1716 case TRACE_REG_PERF_ADD:
1717 case TRACE_REG_PERF_DEL:
1718 return 0;
1719#endif
1720 }
1721 return 0;
1722}
1723
1724static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1725{
1726 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1727 int ret = 0;
1728
1729 raw_cpu_inc(*tk->nhit);
1730
1731 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1732 kprobe_trace_func(tk, regs);
1733#ifdef CONFIG_PERF_EVENTS
1734 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1735 ret = kprobe_perf_func(tk, regs);
1736#endif
1737 return ret;
1738}
1739NOKPROBE_SYMBOL(kprobe_dispatcher);
1740
1741static int
1742kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1743{
1744 struct kretprobe *rp = get_kretprobe(ri);
1745 struct trace_kprobe *tk = container_of(rp, struct trace_kprobe, rp);
1746
1747 raw_cpu_inc(*tk->nhit);
1748
1749 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1750 kretprobe_trace_func(tk, ri, regs);
1751#ifdef CONFIG_PERF_EVENTS
1752 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1753 kretprobe_perf_func(tk, ri, regs);
1754#endif
1755 return 0; /* We don't tweak kernel, so just return 0 */
1756}
1757NOKPROBE_SYMBOL(kretprobe_dispatcher);
1758
1759static struct trace_event_functions kretprobe_funcs = {
1760 .trace = print_kretprobe_event
1761};
1762
1763static struct trace_event_functions kprobe_funcs = {
1764 .trace = print_kprobe_event
1765};
1766
1767static struct trace_event_fields kretprobe_fields_array[] = {
1768 { .type = TRACE_FUNCTION_TYPE,
1769 .define_fields = kretprobe_event_define_fields },
1770 {}
1771};
1772
1773static struct trace_event_fields kprobe_fields_array[] = {
1774 { .type = TRACE_FUNCTION_TYPE,
1775 .define_fields = kprobe_event_define_fields },
1776 {}
1777};
1778
1779static inline void init_trace_event_call(struct trace_kprobe *tk)
1780{
1781 struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1782
1783 if (trace_kprobe_is_return(tk)) {
1784 call->event.funcs = &kretprobe_funcs;
1785 call->class->fields_array = kretprobe_fields_array;
1786 } else {
1787 call->event.funcs = &kprobe_funcs;
1788 call->class->fields_array = kprobe_fields_array;
1789 }
1790
1791 call->flags = TRACE_EVENT_FL_KPROBE;
1792 call->class->reg = kprobe_register;
1793}
1794
1795static int register_kprobe_event(struct trace_kprobe *tk)
1796{
1797 init_trace_event_call(tk);
1798
1799 return trace_probe_register_event_call(&tk->tp);
1800}
1801
1802static int unregister_kprobe_event(struct trace_kprobe *tk)
1803{
1804 return trace_probe_unregister_event_call(&tk->tp);
1805}
1806
1807#ifdef CONFIG_PERF_EVENTS
1808/* create a trace_kprobe, but don't add it to global lists */
1809struct trace_event_call *
1810create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1811 bool is_return)
1812{
1813 struct trace_kprobe *tk;
1814 int ret;
1815 char *event;
1816
1817 /*
1818 * local trace_kprobes are not added to dyn_event, so they are never
1819 * searched in find_trace_kprobe(). Therefore, there is no concern of
1820 * duplicated name here.
1821 */
1822 event = func ? func : "DUMMY_EVENT";
1823
1824 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1825 offs, 0 /* maxactive */, 0 /* nargs */,
1826 is_return);
1827
1828 if (IS_ERR(tk)) {
1829 pr_info("Failed to allocate trace_probe.(%d)\n",
1830 (int)PTR_ERR(tk));
1831 return ERR_CAST(tk);
1832 }
1833
1834 init_trace_event_call(tk);
1835
1836 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1837 ret = -ENOMEM;
1838 goto error;
1839 }
1840
1841 ret = __register_trace_kprobe(tk);
1842 if (ret < 0)
1843 goto error;
1844
1845 return trace_probe_event_call(&tk->tp);
1846error:
1847 free_trace_kprobe(tk);
1848 return ERR_PTR(ret);
1849}
1850
1851void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1852{
1853 struct trace_kprobe *tk;
1854
1855 tk = trace_kprobe_primary_from_call(event_call);
1856 if (unlikely(!tk))
1857 return;
1858
1859 if (trace_probe_is_enabled(&tk->tp)) {
1860 WARN_ON(1);
1861 return;
1862 }
1863
1864 __unregister_trace_kprobe(tk);
1865
1866 free_trace_kprobe(tk);
1867}
1868#endif /* CONFIG_PERF_EVENTS */
1869
1870static __init void enable_boot_kprobe_events(void)
1871{
1872 struct trace_array *tr = top_trace_array();
1873 struct trace_event_file *file;
1874 struct trace_kprobe *tk;
1875 struct dyn_event *pos;
1876
1877 mutex_lock(&event_mutex);
1878 for_each_trace_kprobe(tk, pos) {
1879 list_for_each_entry(file, &tr->events, list)
1880 if (file->event_call == trace_probe_event_call(&tk->tp))
1881 trace_event_enable_disable(file, 1, 0);
1882 }
1883 mutex_unlock(&event_mutex);
1884}
1885
1886static __init void setup_boot_kprobe_events(void)
1887{
1888 char *p, *cmd = kprobe_boot_events_buf;
1889 int ret;
1890
1891 strreplace(kprobe_boot_events_buf, ',', ' ');
1892
1893 while (cmd && *cmd != '\0') {
1894 p = strchr(cmd, ';');
1895 if (p)
1896 *p++ = '\0';
1897
1898 ret = create_or_delete_trace_kprobe(cmd);
1899 if (ret)
1900 pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1901
1902 cmd = p;
1903 }
1904
1905 enable_boot_kprobe_events();
1906}
1907
1908/*
1909 * Register dynevent at core_initcall. This allows kernel to setup kprobe
1910 * events in postcore_initcall without tracefs.
1911 */
1912static __init int init_kprobe_trace_early(void)
1913{
1914 int ret;
1915
1916 ret = dyn_event_register(&trace_kprobe_ops);
1917 if (ret)
1918 return ret;
1919
1920 if (register_module_notifier(&trace_kprobe_module_nb))
1921 return -EINVAL;
1922
1923 return 0;
1924}
1925core_initcall(init_kprobe_trace_early);
1926
1927/* Make a tracefs interface for controlling probe points */
1928static __init int init_kprobe_trace(void)
1929{
1930 int ret;
1931 struct dentry *entry;
1932
1933 ret = tracing_init_dentry();
1934 if (ret)
1935 return 0;
1936
1937 entry = tracefs_create_file("kprobe_events", 0644, NULL,
1938 NULL, &kprobe_events_ops);
1939
1940 /* Event list interface */
1941 if (!entry)
1942 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1943
1944 /* Profile interface */
1945 entry = tracefs_create_file("kprobe_profile", 0444, NULL,
1946 NULL, &kprobe_profile_ops);
1947
1948 if (!entry)
1949 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1950
1951 setup_boot_kprobe_events();
1952
1953 return 0;
1954}
1955fs_initcall(init_kprobe_trace);
1956
1957
1958#ifdef CONFIG_FTRACE_STARTUP_TEST
1959static __init struct trace_event_file *
1960find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1961{
1962 struct trace_event_file *file;
1963
1964 list_for_each_entry(file, &tr->events, list)
1965 if (file->event_call == trace_probe_event_call(&tk->tp))
1966 return file;
1967
1968 return NULL;
1969}
1970
1971/*
1972 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1973 * stage, we can do this lockless.
1974 */
1975static __init int kprobe_trace_self_tests_init(void)
1976{
1977 int ret, warn = 0;
1978 int (*target)(int, int, int, int, int, int);
1979 struct trace_kprobe *tk;
1980 struct trace_event_file *file;
1981
1982 if (tracing_is_disabled())
1983 return -ENODEV;
1984
1985 if (tracing_selftest_disabled)
1986 return 0;
1987
1988 target = kprobe_trace_selftest_target;
1989
1990 pr_info("Testing kprobe tracing: ");
1991
1992 ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
1993 if (WARN_ON_ONCE(ret)) {
1994 pr_warn("error on probing function entry.\n");
1995 warn++;
1996 } else {
1997 /* Enable trace point */
1998 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1999 if (WARN_ON_ONCE(tk == NULL)) {
2000 pr_warn("error on getting new probe.\n");
2001 warn++;
2002 } else {
2003 file = find_trace_probe_file(tk, top_trace_array());
2004 if (WARN_ON_ONCE(file == NULL)) {
2005 pr_warn("error on getting probe file.\n");
2006 warn++;
2007 } else
2008 enable_trace_kprobe(
2009 trace_probe_event_call(&tk->tp), file);
2010 }
2011 }
2012
2013 ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
2014 if (WARN_ON_ONCE(ret)) {
2015 pr_warn("error on probing function return.\n");
2016 warn++;
2017 } else {
2018 /* Enable trace point */
2019 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2020 if (WARN_ON_ONCE(tk == NULL)) {
2021 pr_warn("error on getting 2nd new probe.\n");
2022 warn++;
2023 } else {
2024 file = find_trace_probe_file(tk, top_trace_array());
2025 if (WARN_ON_ONCE(file == NULL)) {
2026 pr_warn("error on getting probe file.\n");
2027 warn++;
2028 } else
2029 enable_trace_kprobe(
2030 trace_probe_event_call(&tk->tp), file);
2031 }
2032 }
2033
2034 if (warn)
2035 goto end;
2036
2037 ret = target(1, 2, 3, 4, 5, 6);
2038
2039 /*
2040 * Not expecting an error here, the check is only to prevent the
2041 * optimizer from removing the call to target() as otherwise there
2042 * are no side-effects and the call is never performed.
2043 */
2044 if (ret != 21)
2045 warn++;
2046
2047 /* Disable trace points before removing it */
2048 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2049 if (WARN_ON_ONCE(tk == NULL)) {
2050 pr_warn("error on getting test probe.\n");
2051 warn++;
2052 } else {
2053 if (trace_kprobe_nhit(tk) != 1) {
2054 pr_warn("incorrect number of testprobe hits\n");
2055 warn++;
2056 }
2057
2058 file = find_trace_probe_file(tk, top_trace_array());
2059 if (WARN_ON_ONCE(file == NULL)) {
2060 pr_warn("error on getting probe file.\n");
2061 warn++;
2062 } else
2063 disable_trace_kprobe(
2064 trace_probe_event_call(&tk->tp), file);
2065 }
2066
2067 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2068 if (WARN_ON_ONCE(tk == NULL)) {
2069 pr_warn("error on getting 2nd test probe.\n");
2070 warn++;
2071 } else {
2072 if (trace_kprobe_nhit(tk) != 1) {
2073 pr_warn("incorrect number of testprobe2 hits\n");
2074 warn++;
2075 }
2076
2077 file = find_trace_probe_file(tk, top_trace_array());
2078 if (WARN_ON_ONCE(file == NULL)) {
2079 pr_warn("error on getting probe file.\n");
2080 warn++;
2081 } else
2082 disable_trace_kprobe(
2083 trace_probe_event_call(&tk->tp), file);
2084 }
2085
2086 ret = create_or_delete_trace_kprobe("-:testprobe");
2087 if (WARN_ON_ONCE(ret)) {
2088 pr_warn("error on deleting a probe.\n");
2089 warn++;
2090 }
2091
2092 ret = create_or_delete_trace_kprobe("-:testprobe2");
2093 if (WARN_ON_ONCE(ret)) {
2094 pr_warn("error on deleting a probe.\n");
2095 warn++;
2096 }
2097
2098end:
2099 ret = dyn_events_release_all(&trace_kprobe_ops);
2100 if (WARN_ON_ONCE(ret)) {
2101 pr_warn("error on cleaning up probes.\n");
2102 warn++;
2103 }
2104 /*
2105 * Wait for the optimizer work to finish. Otherwise it might fiddle
2106 * with probes in already freed __init text.
2107 */
2108 wait_for_kprobe_optimizer();
2109 if (warn)
2110 pr_cont("NG: Some tests are failed. Please check them.\n");
2111 else
2112 pr_cont("OK\n");
2113 return 0;
2114}
2115
2116late_initcall(kprobe_trace_self_tests_init);
2117
2118#endif