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1/*
2 * Kprobes-based tracing events
3 *
4 * Created by Masami Hiramatsu <mhiramat@redhat.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19#define pr_fmt(fmt) "trace_kprobe: " fmt
20
21#include <linux/module.h>
22#include <linux/uaccess.h>
23#include <linux/rculist.h>
24#include <linux/error-injection.h>
25
26#include "trace_probe.h"
27
28#define KPROBE_EVENT_SYSTEM "kprobes"
29#define KRETPROBE_MAXACTIVE_MAX 4096
30
31/**
32 * Kprobe event core functions
33 */
34struct trace_kprobe {
35 struct list_head list;
36 struct kretprobe rp; /* Use rp.kp for kprobe use */
37 unsigned long __percpu *nhit;
38 const char *symbol; /* symbol name */
39 struct trace_probe tp;
40};
41
42#define SIZEOF_TRACE_KPROBE(n) \
43 (offsetof(struct trace_kprobe, tp.args) + \
44 (sizeof(struct probe_arg) * (n)))
45
46static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
47{
48 return tk->rp.handler != NULL;
49}
50
51static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
52{
53 return tk->symbol ? tk->symbol : "unknown";
54}
55
56static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
57{
58 return tk->rp.kp.offset;
59}
60
61static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
62{
63 return !!(kprobe_gone(&tk->rp.kp));
64}
65
66static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
67 struct module *mod)
68{
69 int len = strlen(mod->name);
70 const char *name = trace_kprobe_symbol(tk);
71 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
72}
73
74static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
75{
76 return !!strchr(trace_kprobe_symbol(tk), ':');
77}
78
79static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
80{
81 unsigned long nhit = 0;
82 int cpu;
83
84 for_each_possible_cpu(cpu)
85 nhit += *per_cpu_ptr(tk->nhit, cpu);
86
87 return nhit;
88}
89
90bool trace_kprobe_on_func_entry(struct trace_event_call *call)
91{
92 struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
93
94 return kprobe_on_func_entry(tk->rp.kp.addr,
95 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
96 tk->rp.kp.addr ? 0 : tk->rp.kp.offset);
97}
98
99bool trace_kprobe_error_injectable(struct trace_event_call *call)
100{
101 struct trace_kprobe *tk = (struct trace_kprobe *)call->data;
102 unsigned long addr;
103
104 if (tk->symbol) {
105 addr = (unsigned long)
106 kallsyms_lookup_name(trace_kprobe_symbol(tk));
107 addr += tk->rp.kp.offset;
108 } else {
109 addr = (unsigned long)tk->rp.kp.addr;
110 }
111 return within_error_injection_list(addr);
112}
113
114static int register_kprobe_event(struct trace_kprobe *tk);
115static int unregister_kprobe_event(struct trace_kprobe *tk);
116
117static DEFINE_MUTEX(probe_lock);
118static LIST_HEAD(probe_list);
119
120static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
121static int kretprobe_dispatcher(struct kretprobe_instance *ri,
122 struct pt_regs *regs);
123
124/* Memory fetching by symbol */
125struct symbol_cache {
126 char *symbol;
127 long offset;
128 unsigned long addr;
129};
130
131unsigned long update_symbol_cache(struct symbol_cache *sc)
132{
133 sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
134
135 if (sc->addr)
136 sc->addr += sc->offset;
137
138 return sc->addr;
139}
140
141void free_symbol_cache(struct symbol_cache *sc)
142{
143 kfree(sc->symbol);
144 kfree(sc);
145}
146
147struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
148{
149 struct symbol_cache *sc;
150
151 if (!sym || strlen(sym) == 0)
152 return NULL;
153
154 sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
155 if (!sc)
156 return NULL;
157
158 sc->symbol = kstrdup(sym, GFP_KERNEL);
159 if (!sc->symbol) {
160 kfree(sc);
161 return NULL;
162 }
163 sc->offset = offset;
164 update_symbol_cache(sc);
165
166 return sc;
167}
168
169/*
170 * Kprobes-specific fetch functions
171 */
172#define DEFINE_FETCH_stack(type) \
173static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
174 void *offset, void *dest) \
175{ \
176 *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
177 (unsigned int)((unsigned long)offset)); \
178} \
179NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
180
181DEFINE_BASIC_FETCH_FUNCS(stack)
182/* No string on the stack entry */
183#define fetch_stack_string NULL
184#define fetch_stack_string_size NULL
185
186#define DEFINE_FETCH_memory(type) \
187static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
188 void *addr, void *dest) \
189{ \
190 type retval; \
191 if (probe_kernel_address(addr, retval)) \
192 *(type *)dest = 0; \
193 else \
194 *(type *)dest = retval; \
195} \
196NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
197
198DEFINE_BASIC_FETCH_FUNCS(memory)
199/*
200 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
201 * length and relative data location.
202 */
203static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
204 void *addr, void *dest)
205{
206 int maxlen = get_rloc_len(*(u32 *)dest);
207 u8 *dst = get_rloc_data(dest);
208 long ret;
209
210 if (!maxlen)
211 return;
212
213 /*
214 * Try to get string again, since the string can be changed while
215 * probing.
216 */
217 ret = strncpy_from_unsafe(dst, addr, maxlen);
218
219 if (ret < 0) { /* Failed to fetch string */
220 dst[0] = '\0';
221 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
222 } else {
223 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
224 }
225}
226NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
227
228/* Return the length of string -- including null terminal byte */
229static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
230 void *addr, void *dest)
231{
232 mm_segment_t old_fs;
233 int ret, len = 0;
234 u8 c;
235
236 old_fs = get_fs();
237 set_fs(KERNEL_DS);
238 pagefault_disable();
239
240 do {
241 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
242 len++;
243 } while (c && ret == 0 && len < MAX_STRING_SIZE);
244
245 pagefault_enable();
246 set_fs(old_fs);
247
248 if (ret < 0) /* Failed to check the length */
249 *(u32 *)dest = 0;
250 else
251 *(u32 *)dest = len;
252}
253NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
254
255#define DEFINE_FETCH_symbol(type) \
256void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
257{ \
258 struct symbol_cache *sc = data; \
259 if (sc->addr) \
260 fetch_memory_##type(regs, (void *)sc->addr, dest); \
261 else \
262 *(type *)dest = 0; \
263} \
264NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
265
266DEFINE_BASIC_FETCH_FUNCS(symbol)
267DEFINE_FETCH_symbol(string)
268DEFINE_FETCH_symbol(string_size)
269
270/* kprobes don't support file_offset fetch methods */
271#define fetch_file_offset_u8 NULL
272#define fetch_file_offset_u16 NULL
273#define fetch_file_offset_u32 NULL
274#define fetch_file_offset_u64 NULL
275#define fetch_file_offset_string NULL
276#define fetch_file_offset_string_size NULL
277
278/* Fetch type information table */
279static const struct fetch_type kprobes_fetch_type_table[] = {
280 /* Special types */
281 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
282 sizeof(u32), 1, "__data_loc char[]"),
283 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
284 string_size, sizeof(u32), 0, "u32"),
285 /* Basic types */
286 ASSIGN_FETCH_TYPE(u8, u8, 0),
287 ASSIGN_FETCH_TYPE(u16, u16, 0),
288 ASSIGN_FETCH_TYPE(u32, u32, 0),
289 ASSIGN_FETCH_TYPE(u64, u64, 0),
290 ASSIGN_FETCH_TYPE(s8, u8, 1),
291 ASSIGN_FETCH_TYPE(s16, u16, 1),
292 ASSIGN_FETCH_TYPE(s32, u32, 1),
293 ASSIGN_FETCH_TYPE(s64, u64, 1),
294 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
295 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
296 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
297 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
298
299 ASSIGN_FETCH_TYPE_END
300};
301
302/*
303 * Allocate new trace_probe and initialize it (including kprobes).
304 */
305static struct trace_kprobe *alloc_trace_kprobe(const char *group,
306 const char *event,
307 void *addr,
308 const char *symbol,
309 unsigned long offs,
310 int maxactive,
311 int nargs, bool is_return)
312{
313 struct trace_kprobe *tk;
314 int ret = -ENOMEM;
315
316 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
317 if (!tk)
318 return ERR_PTR(ret);
319
320 tk->nhit = alloc_percpu(unsigned long);
321 if (!tk->nhit)
322 goto error;
323
324 if (symbol) {
325 tk->symbol = kstrdup(symbol, GFP_KERNEL);
326 if (!tk->symbol)
327 goto error;
328 tk->rp.kp.symbol_name = tk->symbol;
329 tk->rp.kp.offset = offs;
330 } else
331 tk->rp.kp.addr = addr;
332
333 if (is_return)
334 tk->rp.handler = kretprobe_dispatcher;
335 else
336 tk->rp.kp.pre_handler = kprobe_dispatcher;
337
338 tk->rp.maxactive = maxactive;
339
340 if (!event || !is_good_name(event)) {
341 ret = -EINVAL;
342 goto error;
343 }
344
345 tk->tp.call.class = &tk->tp.class;
346 tk->tp.call.name = kstrdup(event, GFP_KERNEL);
347 if (!tk->tp.call.name)
348 goto error;
349
350 if (!group || !is_good_name(group)) {
351 ret = -EINVAL;
352 goto error;
353 }
354
355 tk->tp.class.system = kstrdup(group, GFP_KERNEL);
356 if (!tk->tp.class.system)
357 goto error;
358
359 INIT_LIST_HEAD(&tk->list);
360 INIT_LIST_HEAD(&tk->tp.files);
361 return tk;
362error:
363 kfree(tk->tp.call.name);
364 kfree(tk->symbol);
365 free_percpu(tk->nhit);
366 kfree(tk);
367 return ERR_PTR(ret);
368}
369
370static void free_trace_kprobe(struct trace_kprobe *tk)
371{
372 int i;
373
374 for (i = 0; i < tk->tp.nr_args; i++)
375 traceprobe_free_probe_arg(&tk->tp.args[i]);
376
377 kfree(tk->tp.call.class->system);
378 kfree(tk->tp.call.name);
379 kfree(tk->symbol);
380 free_percpu(tk->nhit);
381 kfree(tk);
382}
383
384static struct trace_kprobe *find_trace_kprobe(const char *event,
385 const char *group)
386{
387 struct trace_kprobe *tk;
388
389 list_for_each_entry(tk, &probe_list, list)
390 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
391 strcmp(tk->tp.call.class->system, group) == 0)
392 return tk;
393 return NULL;
394}
395
396/*
397 * Enable trace_probe
398 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
399 */
400static int
401enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
402{
403 int ret = 0;
404
405 if (file) {
406 struct event_file_link *link;
407
408 link = kmalloc(sizeof(*link), GFP_KERNEL);
409 if (!link) {
410 ret = -ENOMEM;
411 goto out;
412 }
413
414 link->file = file;
415 list_add_tail_rcu(&link->list, &tk->tp.files);
416
417 tk->tp.flags |= TP_FLAG_TRACE;
418 } else
419 tk->tp.flags |= TP_FLAG_PROFILE;
420
421 if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
422 if (trace_kprobe_is_return(tk))
423 ret = enable_kretprobe(&tk->rp);
424 else
425 ret = enable_kprobe(&tk->rp.kp);
426 }
427 out:
428 return ret;
429}
430
431/*
432 * Disable trace_probe
433 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
434 */
435static int
436disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
437{
438 struct event_file_link *link = NULL;
439 int wait = 0;
440 int ret = 0;
441
442 if (file) {
443 link = find_event_file_link(&tk->tp, file);
444 if (!link) {
445 ret = -EINVAL;
446 goto out;
447 }
448
449 list_del_rcu(&link->list);
450 wait = 1;
451 if (!list_empty(&tk->tp.files))
452 goto out;
453
454 tk->tp.flags &= ~TP_FLAG_TRACE;
455 } else
456 tk->tp.flags &= ~TP_FLAG_PROFILE;
457
458 if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
459 if (trace_kprobe_is_return(tk))
460 disable_kretprobe(&tk->rp);
461 else
462 disable_kprobe(&tk->rp.kp);
463 wait = 1;
464 }
465
466 /*
467 * if tk is not added to any list, it must be a local trace_kprobe
468 * created with perf_event_open. We don't need to wait for these
469 * trace_kprobes
470 */
471 if (list_empty(&tk->list))
472 wait = 0;
473 out:
474 if (wait) {
475 /*
476 * Synchronize with kprobe_trace_func/kretprobe_trace_func
477 * to ensure disabled (all running handlers are finished).
478 * This is not only for kfree(), but also the caller,
479 * trace_remove_event_call() supposes it for releasing
480 * event_call related objects, which will be accessed in
481 * the kprobe_trace_func/kretprobe_trace_func.
482 */
483 synchronize_sched();
484 kfree(link); /* Ignored if link == NULL */
485 }
486
487 return ret;
488}
489
490/* Internal register function - just handle k*probes and flags */
491static int __register_trace_kprobe(struct trace_kprobe *tk)
492{
493 int i, ret;
494
495 if (trace_probe_is_registered(&tk->tp))
496 return -EINVAL;
497
498 for (i = 0; i < tk->tp.nr_args; i++)
499 traceprobe_update_arg(&tk->tp.args[i]);
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 if (ret == 0)
513 tk->tp.flags |= TP_FLAG_REGISTERED;
514 else {
515 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
516 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
517 ret = 0;
518 } else if (ret == -EILSEQ) {
519 pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
520 tk->rp.kp.addr);
521 ret = -EINVAL;
522 }
523 }
524
525 return ret;
526}
527
528/* Internal unregister function - just handle k*probes and flags */
529static void __unregister_trace_kprobe(struct trace_kprobe *tk)
530{
531 if (trace_probe_is_registered(&tk->tp)) {
532 if (trace_kprobe_is_return(tk))
533 unregister_kretprobe(&tk->rp);
534 else
535 unregister_kprobe(&tk->rp.kp);
536 tk->tp.flags &= ~TP_FLAG_REGISTERED;
537 /* Cleanup kprobe for reuse */
538 if (tk->rp.kp.symbol_name)
539 tk->rp.kp.addr = NULL;
540 }
541}
542
543/* Unregister a trace_probe and probe_event: call with locking probe_lock */
544static int unregister_trace_kprobe(struct trace_kprobe *tk)
545{
546 /* Enabled event can not be unregistered */
547 if (trace_probe_is_enabled(&tk->tp))
548 return -EBUSY;
549
550 /* Will fail if probe is being used by ftrace or perf */
551 if (unregister_kprobe_event(tk))
552 return -EBUSY;
553
554 __unregister_trace_kprobe(tk);
555 list_del(&tk->list);
556
557 return 0;
558}
559
560/* Register a trace_probe and probe_event */
561static int register_trace_kprobe(struct trace_kprobe *tk)
562{
563 struct trace_kprobe *old_tk;
564 int ret;
565
566 mutex_lock(&probe_lock);
567
568 /* Delete old (same name) event if exist */
569 old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
570 tk->tp.call.class->system);
571 if (old_tk) {
572 ret = unregister_trace_kprobe(old_tk);
573 if (ret < 0)
574 goto end;
575 free_trace_kprobe(old_tk);
576 }
577
578 /* Register new event */
579 ret = register_kprobe_event(tk);
580 if (ret) {
581 pr_warn("Failed to register probe event(%d)\n", ret);
582 goto end;
583 }
584
585 /* Register k*probe */
586 ret = __register_trace_kprobe(tk);
587 if (ret < 0)
588 unregister_kprobe_event(tk);
589 else
590 list_add_tail(&tk->list, &probe_list);
591
592end:
593 mutex_unlock(&probe_lock);
594 return ret;
595}
596
597/* Module notifier call back, checking event on the module */
598static int trace_kprobe_module_callback(struct notifier_block *nb,
599 unsigned long val, void *data)
600{
601 struct module *mod = data;
602 struct trace_kprobe *tk;
603 int ret;
604
605 if (val != MODULE_STATE_COMING)
606 return NOTIFY_DONE;
607
608 /* Update probes on coming module */
609 mutex_lock(&probe_lock);
610 list_for_each_entry(tk, &probe_list, list) {
611 if (trace_kprobe_within_module(tk, mod)) {
612 /* Don't need to check busy - this should have gone. */
613 __unregister_trace_kprobe(tk);
614 ret = __register_trace_kprobe(tk);
615 if (ret)
616 pr_warn("Failed to re-register probe %s on %s: %d\n",
617 trace_event_name(&tk->tp.call),
618 mod->name, ret);
619 }
620 }
621 mutex_unlock(&probe_lock);
622
623 return NOTIFY_DONE;
624}
625
626static struct notifier_block trace_kprobe_module_nb = {
627 .notifier_call = trace_kprobe_module_callback,
628 .priority = 1 /* Invoked after kprobe module callback */
629};
630
631/* Convert certain expected symbols into '_' when generating event names */
632static inline void sanitize_event_name(char *name)
633{
634 while (*name++ != '\0')
635 if (*name == ':' || *name == '.')
636 *name = '_';
637}
638
639static int create_trace_kprobe(int argc, char **argv)
640{
641 /*
642 * Argument syntax:
643 * - Add kprobe:
644 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
645 * - Add kretprobe:
646 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
647 * Fetch args:
648 * $retval : fetch return value
649 * $stack : fetch stack address
650 * $stackN : fetch Nth of stack (N:0-)
651 * $comm : fetch current task comm
652 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
653 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
654 * %REG : fetch register REG
655 * Dereferencing memory fetch:
656 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
657 * Alias name of args:
658 * NAME=FETCHARG : set NAME as alias of FETCHARG.
659 * Type of args:
660 * FETCHARG:TYPE : use TYPE instead of unsigned long.
661 */
662 struct trace_kprobe *tk;
663 int i, ret = 0;
664 bool is_return = false, is_delete = false;
665 char *symbol = NULL, *event = NULL, *group = NULL;
666 int maxactive = 0;
667 char *arg;
668 long offset = 0;
669 void *addr = NULL;
670 char buf[MAX_EVENT_NAME_LEN];
671
672 /* argc must be >= 1 */
673 if (argv[0][0] == 'p')
674 is_return = false;
675 else if (argv[0][0] == 'r')
676 is_return = true;
677 else if (argv[0][0] == '-')
678 is_delete = true;
679 else {
680 pr_info("Probe definition must be started with 'p', 'r' or"
681 " '-'.\n");
682 return -EINVAL;
683 }
684
685 event = strchr(&argv[0][1], ':');
686 if (event) {
687 event[0] = '\0';
688 event++;
689 }
690 if (is_return && isdigit(argv[0][1])) {
691 ret = kstrtouint(&argv[0][1], 0, &maxactive);
692 if (ret) {
693 pr_info("Failed to parse maxactive.\n");
694 return ret;
695 }
696 /* kretprobes instances are iterated over via a list. The
697 * maximum should stay reasonable.
698 */
699 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
700 pr_info("Maxactive is too big (%d > %d).\n",
701 maxactive, KRETPROBE_MAXACTIVE_MAX);
702 return -E2BIG;
703 }
704 }
705
706 if (event) {
707 if (strchr(event, '/')) {
708 group = event;
709 event = strchr(group, '/') + 1;
710 event[-1] = '\0';
711 if (strlen(group) == 0) {
712 pr_info("Group name is not specified\n");
713 return -EINVAL;
714 }
715 }
716 if (strlen(event) == 0) {
717 pr_info("Event name is not specified\n");
718 return -EINVAL;
719 }
720 }
721 if (!group)
722 group = KPROBE_EVENT_SYSTEM;
723
724 if (is_delete) {
725 if (!event) {
726 pr_info("Delete command needs an event name.\n");
727 return -EINVAL;
728 }
729 mutex_lock(&probe_lock);
730 tk = find_trace_kprobe(event, group);
731 if (!tk) {
732 mutex_unlock(&probe_lock);
733 pr_info("Event %s/%s doesn't exist.\n", group, event);
734 return -ENOENT;
735 }
736 /* delete an event */
737 ret = unregister_trace_kprobe(tk);
738 if (ret == 0)
739 free_trace_kprobe(tk);
740 mutex_unlock(&probe_lock);
741 return ret;
742 }
743
744 if (argc < 2) {
745 pr_info("Probe point is not specified.\n");
746 return -EINVAL;
747 }
748
749 /* try to parse an address. if that fails, try to read the
750 * input as a symbol. */
751 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
752 /* a symbol specified */
753 symbol = argv[1];
754 /* TODO: support .init module functions */
755 ret = traceprobe_split_symbol_offset(symbol, &offset);
756 if (ret || offset < 0 || offset > UINT_MAX) {
757 pr_info("Failed to parse either an address or a symbol.\n");
758 return ret;
759 }
760 if (offset && is_return &&
761 !kprobe_on_func_entry(NULL, symbol, offset)) {
762 pr_info("Given offset is not valid for return probe.\n");
763 return -EINVAL;
764 }
765 }
766 argc -= 2; argv += 2;
767
768 /* setup a probe */
769 if (!event) {
770 /* Make a new event name */
771 if (symbol)
772 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
773 is_return ? 'r' : 'p', symbol, offset);
774 else
775 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
776 is_return ? 'r' : 'p', addr);
777 sanitize_event_name(buf);
778 event = buf;
779 }
780 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
781 argc, is_return);
782 if (IS_ERR(tk)) {
783 pr_info("Failed to allocate trace_probe.(%d)\n",
784 (int)PTR_ERR(tk));
785 return PTR_ERR(tk);
786 }
787
788 /* parse arguments */
789 ret = 0;
790 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
791 struct probe_arg *parg = &tk->tp.args[i];
792
793 /* Increment count for freeing args in error case */
794 tk->tp.nr_args++;
795
796 /* Parse argument name */
797 arg = strchr(argv[i], '=');
798 if (arg) {
799 *arg++ = '\0';
800 parg->name = kstrdup(argv[i], GFP_KERNEL);
801 } else {
802 arg = argv[i];
803 /* If argument name is omitted, set "argN" */
804 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
805 parg->name = kstrdup(buf, GFP_KERNEL);
806 }
807
808 if (!parg->name) {
809 pr_info("Failed to allocate argument[%d] name.\n", i);
810 ret = -ENOMEM;
811 goto error;
812 }
813
814 if (!is_good_name(parg->name)) {
815 pr_info("Invalid argument[%d] name: %s\n",
816 i, parg->name);
817 ret = -EINVAL;
818 goto error;
819 }
820
821 if (traceprobe_conflict_field_name(parg->name,
822 tk->tp.args, i)) {
823 pr_info("Argument[%d] name '%s' conflicts with "
824 "another field.\n", i, argv[i]);
825 ret = -EINVAL;
826 goto error;
827 }
828
829 /* Parse fetch argument */
830 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
831 is_return, true,
832 kprobes_fetch_type_table);
833 if (ret) {
834 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
835 goto error;
836 }
837 }
838
839 ret = register_trace_kprobe(tk);
840 if (ret)
841 goto error;
842 return 0;
843
844error:
845 free_trace_kprobe(tk);
846 return ret;
847}
848
849static int release_all_trace_kprobes(void)
850{
851 struct trace_kprobe *tk;
852 int ret = 0;
853
854 mutex_lock(&probe_lock);
855 /* Ensure no probe is in use. */
856 list_for_each_entry(tk, &probe_list, list)
857 if (trace_probe_is_enabled(&tk->tp)) {
858 ret = -EBUSY;
859 goto end;
860 }
861 /* TODO: Use batch unregistration */
862 while (!list_empty(&probe_list)) {
863 tk = list_entry(probe_list.next, struct trace_kprobe, list);
864 ret = unregister_trace_kprobe(tk);
865 if (ret)
866 goto end;
867 free_trace_kprobe(tk);
868 }
869
870end:
871 mutex_unlock(&probe_lock);
872
873 return ret;
874}
875
876/* Probes listing interfaces */
877static void *probes_seq_start(struct seq_file *m, loff_t *pos)
878{
879 mutex_lock(&probe_lock);
880 return seq_list_start(&probe_list, *pos);
881}
882
883static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
884{
885 return seq_list_next(v, &probe_list, pos);
886}
887
888static void probes_seq_stop(struct seq_file *m, void *v)
889{
890 mutex_unlock(&probe_lock);
891}
892
893static int probes_seq_show(struct seq_file *m, void *v)
894{
895 struct trace_kprobe *tk = v;
896 int i;
897
898 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
899 seq_printf(m, ":%s/%s", tk->tp.call.class->system,
900 trace_event_name(&tk->tp.call));
901
902 if (!tk->symbol)
903 seq_printf(m, " 0x%p", tk->rp.kp.addr);
904 else if (tk->rp.kp.offset)
905 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
906 tk->rp.kp.offset);
907 else
908 seq_printf(m, " %s", trace_kprobe_symbol(tk));
909
910 for (i = 0; i < tk->tp.nr_args; i++)
911 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
912 seq_putc(m, '\n');
913
914 return 0;
915}
916
917static const struct seq_operations probes_seq_op = {
918 .start = probes_seq_start,
919 .next = probes_seq_next,
920 .stop = probes_seq_stop,
921 .show = probes_seq_show
922};
923
924static int probes_open(struct inode *inode, struct file *file)
925{
926 int ret;
927
928 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
929 ret = release_all_trace_kprobes();
930 if (ret < 0)
931 return ret;
932 }
933
934 return seq_open(file, &probes_seq_op);
935}
936
937static ssize_t probes_write(struct file *file, const char __user *buffer,
938 size_t count, loff_t *ppos)
939{
940 return trace_parse_run_command(file, buffer, count, ppos,
941 create_trace_kprobe);
942}
943
944static const struct file_operations kprobe_events_ops = {
945 .owner = THIS_MODULE,
946 .open = probes_open,
947 .read = seq_read,
948 .llseek = seq_lseek,
949 .release = seq_release,
950 .write = probes_write,
951};
952
953/* Probes profiling interfaces */
954static int probes_profile_seq_show(struct seq_file *m, void *v)
955{
956 struct trace_kprobe *tk = v;
957
958 seq_printf(m, " %-44s %15lu %15lu\n",
959 trace_event_name(&tk->tp.call),
960 trace_kprobe_nhit(tk),
961 tk->rp.kp.nmissed);
962
963 return 0;
964}
965
966static const struct seq_operations profile_seq_op = {
967 .start = probes_seq_start,
968 .next = probes_seq_next,
969 .stop = probes_seq_stop,
970 .show = probes_profile_seq_show
971};
972
973static int profile_open(struct inode *inode, struct file *file)
974{
975 return seq_open(file, &profile_seq_op);
976}
977
978static const struct file_operations kprobe_profile_ops = {
979 .owner = THIS_MODULE,
980 .open = profile_open,
981 .read = seq_read,
982 .llseek = seq_lseek,
983 .release = seq_release,
984};
985
986/* Kprobe handler */
987static nokprobe_inline void
988__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
989 struct trace_event_file *trace_file)
990{
991 struct kprobe_trace_entry_head *entry;
992 struct ring_buffer_event *event;
993 struct ring_buffer *buffer;
994 int size, dsize, pc;
995 unsigned long irq_flags;
996 struct trace_event_call *call = &tk->tp.call;
997
998 WARN_ON(call != trace_file->event_call);
999
1000 if (trace_trigger_soft_disabled(trace_file))
1001 return;
1002
1003 local_save_flags(irq_flags);
1004 pc = preempt_count();
1005
1006 dsize = __get_data_size(&tk->tp, regs);
1007 size = sizeof(*entry) + tk->tp.size + dsize;
1008
1009 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1010 call->event.type,
1011 size, irq_flags, pc);
1012 if (!event)
1013 return;
1014
1015 entry = ring_buffer_event_data(event);
1016 entry->ip = (unsigned long)tk->rp.kp.addr;
1017 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1018
1019 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1020 entry, irq_flags, pc, regs);
1021}
1022
1023static void
1024kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1025{
1026 struct event_file_link *link;
1027
1028 list_for_each_entry_rcu(link, &tk->tp.files, list)
1029 __kprobe_trace_func(tk, regs, link->file);
1030}
1031NOKPROBE_SYMBOL(kprobe_trace_func);
1032
1033/* Kretprobe handler */
1034static nokprobe_inline void
1035__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1036 struct pt_regs *regs,
1037 struct trace_event_file *trace_file)
1038{
1039 struct kretprobe_trace_entry_head *entry;
1040 struct ring_buffer_event *event;
1041 struct ring_buffer *buffer;
1042 int size, pc, dsize;
1043 unsigned long irq_flags;
1044 struct trace_event_call *call = &tk->tp.call;
1045
1046 WARN_ON(call != trace_file->event_call);
1047
1048 if (trace_trigger_soft_disabled(trace_file))
1049 return;
1050
1051 local_save_flags(irq_flags);
1052 pc = preempt_count();
1053
1054 dsize = __get_data_size(&tk->tp, regs);
1055 size = sizeof(*entry) + tk->tp.size + dsize;
1056
1057 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
1058 call->event.type,
1059 size, irq_flags, pc);
1060 if (!event)
1061 return;
1062
1063 entry = ring_buffer_event_data(event);
1064 entry->func = (unsigned long)tk->rp.kp.addr;
1065 entry->ret_ip = (unsigned long)ri->ret_addr;
1066 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1067
1068 event_trigger_unlock_commit_regs(trace_file, buffer, event,
1069 entry, irq_flags, pc, regs);
1070}
1071
1072static void
1073kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1074 struct pt_regs *regs)
1075{
1076 struct event_file_link *link;
1077
1078 list_for_each_entry_rcu(link, &tk->tp.files, list)
1079 __kretprobe_trace_func(tk, ri, regs, link->file);
1080}
1081NOKPROBE_SYMBOL(kretprobe_trace_func);
1082
1083/* Event entry printers */
1084static enum print_line_t
1085print_kprobe_event(struct trace_iterator *iter, int flags,
1086 struct trace_event *event)
1087{
1088 struct kprobe_trace_entry_head *field;
1089 struct trace_seq *s = &iter->seq;
1090 struct trace_probe *tp;
1091 u8 *data;
1092 int i;
1093
1094 field = (struct kprobe_trace_entry_head *)iter->ent;
1095 tp = container_of(event, struct trace_probe, call.event);
1096
1097 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1098
1099 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1100 goto out;
1101
1102 trace_seq_putc(s, ')');
1103
1104 data = (u8 *)&field[1];
1105 for (i = 0; i < tp->nr_args; i++)
1106 if (!tp->args[i].type->print(s, tp->args[i].name,
1107 data + tp->args[i].offset, field))
1108 goto out;
1109
1110 trace_seq_putc(s, '\n');
1111 out:
1112 return trace_handle_return(s);
1113}
1114
1115static enum print_line_t
1116print_kretprobe_event(struct trace_iterator *iter, int flags,
1117 struct trace_event *event)
1118{
1119 struct kretprobe_trace_entry_head *field;
1120 struct trace_seq *s = &iter->seq;
1121 struct trace_probe *tp;
1122 u8 *data;
1123 int i;
1124
1125 field = (struct kretprobe_trace_entry_head *)iter->ent;
1126 tp = container_of(event, struct trace_probe, call.event);
1127
1128 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
1129
1130 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1131 goto out;
1132
1133 trace_seq_puts(s, " <- ");
1134
1135 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1136 goto out;
1137
1138 trace_seq_putc(s, ')');
1139
1140 data = (u8 *)&field[1];
1141 for (i = 0; i < tp->nr_args; i++)
1142 if (!tp->args[i].type->print(s, tp->args[i].name,
1143 data + tp->args[i].offset, field))
1144 goto out;
1145
1146 trace_seq_putc(s, '\n');
1147
1148 out:
1149 return trace_handle_return(s);
1150}
1151
1152
1153static int kprobe_event_define_fields(struct trace_event_call *event_call)
1154{
1155 int ret, i;
1156 struct kprobe_trace_entry_head field;
1157 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1158
1159 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1160 /* Set argument names as fields */
1161 for (i = 0; i < tk->tp.nr_args; i++) {
1162 struct probe_arg *parg = &tk->tp.args[i];
1163
1164 ret = trace_define_field(event_call, parg->type->fmttype,
1165 parg->name,
1166 sizeof(field) + parg->offset,
1167 parg->type->size,
1168 parg->type->is_signed,
1169 FILTER_OTHER);
1170 if (ret)
1171 return ret;
1172 }
1173 return 0;
1174}
1175
1176static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1177{
1178 int ret, i;
1179 struct kretprobe_trace_entry_head field;
1180 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
1181
1182 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1183 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1184 /* Set argument names as fields */
1185 for (i = 0; i < tk->tp.nr_args; i++) {
1186 struct probe_arg *parg = &tk->tp.args[i];
1187
1188 ret = trace_define_field(event_call, parg->type->fmttype,
1189 parg->name,
1190 sizeof(field) + parg->offset,
1191 parg->type->size,
1192 parg->type->is_signed,
1193 FILTER_OTHER);
1194 if (ret)
1195 return ret;
1196 }
1197 return 0;
1198}
1199
1200#ifdef CONFIG_PERF_EVENTS
1201
1202/* Kprobe profile handler */
1203static int
1204kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1205{
1206 struct trace_event_call *call = &tk->tp.call;
1207 struct kprobe_trace_entry_head *entry;
1208 struct hlist_head *head;
1209 int size, __size, dsize;
1210 int rctx;
1211
1212 if (bpf_prog_array_valid(call)) {
1213 unsigned long orig_ip = instruction_pointer(regs);
1214 int ret;
1215
1216 ret = trace_call_bpf(call, regs);
1217
1218 /*
1219 * We need to check and see if we modified the pc of the
1220 * pt_regs, and if so clear the kprobe and return 1 so that we
1221 * don't do the single stepping.
1222 * The ftrace kprobe handler leaves it up to us to re-enable
1223 * preemption here before returning if we've modified the ip.
1224 */
1225 if (orig_ip != instruction_pointer(regs)) {
1226 reset_current_kprobe();
1227 preempt_enable_no_resched();
1228 return 1;
1229 }
1230 if (!ret)
1231 return 0;
1232 }
1233
1234 head = this_cpu_ptr(call->perf_events);
1235 if (hlist_empty(head))
1236 return 0;
1237
1238 dsize = __get_data_size(&tk->tp, regs);
1239 __size = sizeof(*entry) + tk->tp.size + dsize;
1240 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1241 size -= sizeof(u32);
1242
1243 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1244 if (!entry)
1245 return 0;
1246
1247 entry->ip = (unsigned long)tk->rp.kp.addr;
1248 memset(&entry[1], 0, dsize);
1249 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1250 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1251 head, NULL);
1252 return 0;
1253}
1254NOKPROBE_SYMBOL(kprobe_perf_func);
1255
1256/* Kretprobe profile handler */
1257static void
1258kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1259 struct pt_regs *regs)
1260{
1261 struct trace_event_call *call = &tk->tp.call;
1262 struct kretprobe_trace_entry_head *entry;
1263 struct hlist_head *head;
1264 int size, __size, dsize;
1265 int rctx;
1266
1267 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1268 return;
1269
1270 head = this_cpu_ptr(call->perf_events);
1271 if (hlist_empty(head))
1272 return;
1273
1274 dsize = __get_data_size(&tk->tp, regs);
1275 __size = sizeof(*entry) + tk->tp.size + dsize;
1276 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1277 size -= sizeof(u32);
1278
1279 entry = perf_trace_buf_alloc(size, NULL, &rctx);
1280 if (!entry)
1281 return;
1282
1283 entry->func = (unsigned long)tk->rp.kp.addr;
1284 entry->ret_ip = (unsigned long)ri->ret_addr;
1285 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1286 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1287 head, NULL);
1288}
1289NOKPROBE_SYMBOL(kretprobe_perf_func);
1290#endif /* CONFIG_PERF_EVENTS */
1291
1292/*
1293 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1294 *
1295 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1296 * lockless, but we can't race with this __init function.
1297 */
1298static int kprobe_register(struct trace_event_call *event,
1299 enum trace_reg type, void *data)
1300{
1301 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
1302 struct trace_event_file *file = data;
1303
1304 switch (type) {
1305 case TRACE_REG_REGISTER:
1306 return enable_trace_kprobe(tk, file);
1307 case TRACE_REG_UNREGISTER:
1308 return disable_trace_kprobe(tk, file);
1309
1310#ifdef CONFIG_PERF_EVENTS
1311 case TRACE_REG_PERF_REGISTER:
1312 return enable_trace_kprobe(tk, NULL);
1313 case TRACE_REG_PERF_UNREGISTER:
1314 return disable_trace_kprobe(tk, NULL);
1315 case TRACE_REG_PERF_OPEN:
1316 case TRACE_REG_PERF_CLOSE:
1317 case TRACE_REG_PERF_ADD:
1318 case TRACE_REG_PERF_DEL:
1319 return 0;
1320#endif
1321 }
1322 return 0;
1323}
1324
1325static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1326{
1327 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1328 int ret = 0;
1329
1330 raw_cpu_inc(*tk->nhit);
1331
1332 if (tk->tp.flags & TP_FLAG_TRACE)
1333 kprobe_trace_func(tk, regs);
1334#ifdef CONFIG_PERF_EVENTS
1335 if (tk->tp.flags & TP_FLAG_PROFILE)
1336 ret = kprobe_perf_func(tk, regs);
1337#endif
1338 return ret;
1339}
1340NOKPROBE_SYMBOL(kprobe_dispatcher);
1341
1342static int
1343kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1344{
1345 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1346
1347 raw_cpu_inc(*tk->nhit);
1348
1349 if (tk->tp.flags & TP_FLAG_TRACE)
1350 kretprobe_trace_func(tk, ri, regs);
1351#ifdef CONFIG_PERF_EVENTS
1352 if (tk->tp.flags & TP_FLAG_PROFILE)
1353 kretprobe_perf_func(tk, ri, regs);
1354#endif
1355 return 0; /* We don't tweek kernel, so just return 0 */
1356}
1357NOKPROBE_SYMBOL(kretprobe_dispatcher);
1358
1359static struct trace_event_functions kretprobe_funcs = {
1360 .trace = print_kretprobe_event
1361};
1362
1363static struct trace_event_functions kprobe_funcs = {
1364 .trace = print_kprobe_event
1365};
1366
1367static inline void init_trace_event_call(struct trace_kprobe *tk,
1368 struct trace_event_call *call)
1369{
1370 INIT_LIST_HEAD(&call->class->fields);
1371 if (trace_kprobe_is_return(tk)) {
1372 call->event.funcs = &kretprobe_funcs;
1373 call->class->define_fields = kretprobe_event_define_fields;
1374 } else {
1375 call->event.funcs = &kprobe_funcs;
1376 call->class->define_fields = kprobe_event_define_fields;
1377 }
1378
1379 call->flags = TRACE_EVENT_FL_KPROBE;
1380 call->class->reg = kprobe_register;
1381 call->data = tk;
1382}
1383
1384static int register_kprobe_event(struct trace_kprobe *tk)
1385{
1386 struct trace_event_call *call = &tk->tp.call;
1387 int ret = 0;
1388
1389 init_trace_event_call(tk, call);
1390
1391 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
1392 return -ENOMEM;
1393 ret = register_trace_event(&call->event);
1394 if (!ret) {
1395 kfree(call->print_fmt);
1396 return -ENODEV;
1397 }
1398 ret = trace_add_event_call(call);
1399 if (ret) {
1400 pr_info("Failed to register kprobe event: %s\n",
1401 trace_event_name(call));
1402 kfree(call->print_fmt);
1403 unregister_trace_event(&call->event);
1404 }
1405 return ret;
1406}
1407
1408static int unregister_kprobe_event(struct trace_kprobe *tk)
1409{
1410 int ret;
1411
1412 /* tp->event is unregistered in trace_remove_event_call() */
1413 ret = trace_remove_event_call(&tk->tp.call);
1414 if (!ret)
1415 kfree(tk->tp.call.print_fmt);
1416 return ret;
1417}
1418
1419#ifdef CONFIG_PERF_EVENTS
1420/* create a trace_kprobe, but don't add it to global lists */
1421struct trace_event_call *
1422create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1423 bool is_return)
1424{
1425 struct trace_kprobe *tk;
1426 int ret;
1427 char *event;
1428
1429 /*
1430 * local trace_kprobes are not added to probe_list, so they are never
1431 * searched in find_trace_kprobe(). Therefore, there is no concern of
1432 * duplicated name here.
1433 */
1434 event = func ? func : "DUMMY_EVENT";
1435
1436 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1437 offs, 0 /* maxactive */, 0 /* nargs */,
1438 is_return);
1439
1440 if (IS_ERR(tk)) {
1441 pr_info("Failed to allocate trace_probe.(%d)\n",
1442 (int)PTR_ERR(tk));
1443 return ERR_CAST(tk);
1444 }
1445
1446 init_trace_event_call(tk, &tk->tp.call);
1447
1448 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1449 ret = -ENOMEM;
1450 goto error;
1451 }
1452
1453 ret = __register_trace_kprobe(tk);
1454 if (ret < 0)
1455 goto error;
1456
1457 return &tk->tp.call;
1458error:
1459 free_trace_kprobe(tk);
1460 return ERR_PTR(ret);
1461}
1462
1463void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1464{
1465 struct trace_kprobe *tk;
1466
1467 tk = container_of(event_call, struct trace_kprobe, tp.call);
1468
1469 if (trace_probe_is_enabled(&tk->tp)) {
1470 WARN_ON(1);
1471 return;
1472 }
1473
1474 __unregister_trace_kprobe(tk);
1475 free_trace_kprobe(tk);
1476}
1477#endif /* CONFIG_PERF_EVENTS */
1478
1479/* Make a tracefs interface for controlling probe points */
1480static __init int init_kprobe_trace(void)
1481{
1482 struct dentry *d_tracer;
1483 struct dentry *entry;
1484
1485 if (register_module_notifier(&trace_kprobe_module_nb))
1486 return -EINVAL;
1487
1488 d_tracer = tracing_init_dentry();
1489 if (IS_ERR(d_tracer))
1490 return 0;
1491
1492 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1493 NULL, &kprobe_events_ops);
1494
1495 /* Event list interface */
1496 if (!entry)
1497 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1498
1499 /* Profile interface */
1500 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1501 NULL, &kprobe_profile_ops);
1502
1503 if (!entry)
1504 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1505 return 0;
1506}
1507fs_initcall(init_kprobe_trace);
1508
1509
1510#ifdef CONFIG_FTRACE_STARTUP_TEST
1511/*
1512 * The "__used" keeps gcc from removing the function symbol
1513 * from the kallsyms table. 'noinline' makes sure that there
1514 * isn't an inlined version used by the test method below
1515 */
1516static __used __init noinline int
1517kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
1518{
1519 return a1 + a2 + a3 + a4 + a5 + a6;
1520}
1521
1522static __init struct trace_event_file *
1523find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1524{
1525 struct trace_event_file *file;
1526
1527 list_for_each_entry(file, &tr->events, list)
1528 if (file->event_call == &tk->tp.call)
1529 return file;
1530
1531 return NULL;
1532}
1533
1534/*
1535 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1536 * stage, we can do this lockless.
1537 */
1538static __init int kprobe_trace_self_tests_init(void)
1539{
1540 int ret, warn = 0;
1541 int (*target)(int, int, int, int, int, int);
1542 struct trace_kprobe *tk;
1543 struct trace_event_file *file;
1544
1545 if (tracing_is_disabled())
1546 return -ENODEV;
1547
1548 target = kprobe_trace_selftest_target;
1549
1550 pr_info("Testing kprobe tracing: ");
1551
1552 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target "
1553 "$stack $stack0 +0($stack)",
1554 create_trace_kprobe);
1555 if (WARN_ON_ONCE(ret)) {
1556 pr_warn("error on probing function entry.\n");
1557 warn++;
1558 } else {
1559 /* Enable trace point */
1560 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1561 if (WARN_ON_ONCE(tk == NULL)) {
1562 pr_warn("error on getting new probe.\n");
1563 warn++;
1564 } else {
1565 file = find_trace_probe_file(tk, top_trace_array());
1566 if (WARN_ON_ONCE(file == NULL)) {
1567 pr_warn("error on getting probe file.\n");
1568 warn++;
1569 } else
1570 enable_trace_kprobe(tk, file);
1571 }
1572 }
1573
1574 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target "
1575 "$retval", create_trace_kprobe);
1576 if (WARN_ON_ONCE(ret)) {
1577 pr_warn("error on probing function return.\n");
1578 warn++;
1579 } else {
1580 /* Enable trace point */
1581 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1582 if (WARN_ON_ONCE(tk == NULL)) {
1583 pr_warn("error on getting 2nd new probe.\n");
1584 warn++;
1585 } else {
1586 file = find_trace_probe_file(tk, top_trace_array());
1587 if (WARN_ON_ONCE(file == NULL)) {
1588 pr_warn("error on getting probe file.\n");
1589 warn++;
1590 } else
1591 enable_trace_kprobe(tk, file);
1592 }
1593 }
1594
1595 if (warn)
1596 goto end;
1597
1598 ret = target(1, 2, 3, 4, 5, 6);
1599
1600 /*
1601 * Not expecting an error here, the check is only to prevent the
1602 * optimizer from removing the call to target() as otherwise there
1603 * are no side-effects and the call is never performed.
1604 */
1605 if (ret != 21)
1606 warn++;
1607
1608 /* Disable trace points before removing it */
1609 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1610 if (WARN_ON_ONCE(tk == NULL)) {
1611 pr_warn("error on getting test probe.\n");
1612 warn++;
1613 } else {
1614 if (trace_kprobe_nhit(tk) != 1) {
1615 pr_warn("incorrect number of testprobe hits\n");
1616 warn++;
1617 }
1618
1619 file = find_trace_probe_file(tk, top_trace_array());
1620 if (WARN_ON_ONCE(file == NULL)) {
1621 pr_warn("error on getting probe file.\n");
1622 warn++;
1623 } else
1624 disable_trace_kprobe(tk, file);
1625 }
1626
1627 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1628 if (WARN_ON_ONCE(tk == NULL)) {
1629 pr_warn("error on getting 2nd test probe.\n");
1630 warn++;
1631 } else {
1632 if (trace_kprobe_nhit(tk) != 1) {
1633 pr_warn("incorrect number of testprobe2 hits\n");
1634 warn++;
1635 }
1636
1637 file = find_trace_probe_file(tk, top_trace_array());
1638 if (WARN_ON_ONCE(file == NULL)) {
1639 pr_warn("error on getting probe file.\n");
1640 warn++;
1641 } else
1642 disable_trace_kprobe(tk, file);
1643 }
1644
1645 ret = trace_run_command("-:testprobe", create_trace_kprobe);
1646 if (WARN_ON_ONCE(ret)) {
1647 pr_warn("error on deleting a probe.\n");
1648 warn++;
1649 }
1650
1651 ret = trace_run_command("-:testprobe2", create_trace_kprobe);
1652 if (WARN_ON_ONCE(ret)) {
1653 pr_warn("error on deleting a probe.\n");
1654 warn++;
1655 }
1656
1657end:
1658 release_all_trace_kprobes();
1659 /*
1660 * Wait for the optimizer work to finish. Otherwise it might fiddle
1661 * with probes in already freed __init text.
1662 */
1663 wait_for_kprobe_optimizer();
1664 if (warn)
1665 pr_cont("NG: Some tests are failed. Please check them.\n");
1666 else
1667 pr_cont("OK\n");
1668 return 0;
1669}
1670
1671late_initcall(kprobe_trace_self_tests_init);
1672
1673#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