Loading...
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/*
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
20#include <linux/module.h>
21#include <linux/uaccess.h>
22#include <linux/kprobes.h>
23#include <linux/seq_file.h>
24#include <linux/slab.h>
25#include <linux/smp.h>
26#include <linux/debugfs.h>
27#include <linux/types.h>
28#include <linux/string.h>
29#include <linux/ctype.h>
30#include <linux/ptrace.h>
31#include <linux/perf_event.h>
32#include <linux/stringify.h>
33#include <linux/limits.h>
34#include <asm/bitsperlong.h>
35
36#include "trace.h"
37#include "trace_output.h"
38
39#define MAX_TRACE_ARGS 128
40#define MAX_ARGSTR_LEN 63
41#define MAX_EVENT_NAME_LEN 64
42#define MAX_STRING_SIZE PATH_MAX
43#define KPROBE_EVENT_SYSTEM "kprobes"
44
45/* Reserved field names */
46#define FIELD_STRING_IP "__probe_ip"
47#define FIELD_STRING_RETIP "__probe_ret_ip"
48#define FIELD_STRING_FUNC "__probe_func"
49
50const char *reserved_field_names[] = {
51 "common_type",
52 "common_flags",
53 "common_preempt_count",
54 "common_pid",
55 "common_tgid",
56 FIELD_STRING_IP,
57 FIELD_STRING_RETIP,
58 FIELD_STRING_FUNC,
59};
60
61/* Printing function type */
62typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *,
63 void *);
64#define PRINT_TYPE_FUNC_NAME(type) print_type_##type
65#define PRINT_TYPE_FMT_NAME(type) print_type_format_##type
66
67/* Printing in basic type function template */
68#define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt, cast) \
69static __kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, \
70 const char *name, \
71 void *data, void *ent)\
72{ \
73 return trace_seq_printf(s, " %s=" fmt, name, (cast)*(type *)data);\
74} \
75static const char PRINT_TYPE_FMT_NAME(type)[] = fmt;
76
77DEFINE_BASIC_PRINT_TYPE_FUNC(u8, "%x", unsigned int)
78DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "%x", unsigned int)
79DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "%lx", unsigned long)
80DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "%llx", unsigned long long)
81DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d", int)
82DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d", int)
83DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%ld", long)
84DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%lld", long long)
85
86/* data_rloc: data relative location, compatible with u32 */
87#define make_data_rloc(len, roffs) \
88 (((u32)(len) << 16) | ((u32)(roffs) & 0xffff))
89#define get_rloc_len(dl) ((u32)(dl) >> 16)
90#define get_rloc_offs(dl) ((u32)(dl) & 0xffff)
91
92static inline void *get_rloc_data(u32 *dl)
93{
94 return (u8 *)dl + get_rloc_offs(*dl);
95}
96
97/* For data_loc conversion */
98static inline void *get_loc_data(u32 *dl, void *ent)
99{
100 return (u8 *)ent + get_rloc_offs(*dl);
101}
102
103/*
104 * Convert data_rloc to data_loc:
105 * data_rloc stores the offset from data_rloc itself, but data_loc
106 * stores the offset from event entry.
107 */
108#define convert_rloc_to_loc(dl, offs) ((u32)(dl) + (offs))
109
110/* For defining macros, define string/string_size types */
111typedef u32 string;
112typedef u32 string_size;
113
114/* Print type function for string type */
115static __kprobes int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s,
116 const char *name,
117 void *data, void *ent)
118{
119 int len = *(u32 *)data >> 16;
120
121 if (!len)
122 return trace_seq_printf(s, " %s=(fault)", name);
123 else
124 return trace_seq_printf(s, " %s=\"%s\"", name,
125 (const char *)get_loc_data(data, ent));
126}
127static const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
128
129/* Data fetch function type */
130typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
131
132struct fetch_param {
133 fetch_func_t fn;
134 void *data;
135};
136
137static __kprobes void call_fetch(struct fetch_param *fprm,
138 struct pt_regs *regs, void *dest)
139{
140 return fprm->fn(regs, fprm->data, dest);
141}
142
143#define FETCH_FUNC_NAME(method, type) fetch_##method##_##type
144/*
145 * Define macro for basic types - we don't need to define s* types, because
146 * we have to care only about bitwidth at recording time.
147 */
148#define DEFINE_BASIC_FETCH_FUNCS(method) \
149DEFINE_FETCH_##method(u8) \
150DEFINE_FETCH_##method(u16) \
151DEFINE_FETCH_##method(u32) \
152DEFINE_FETCH_##method(u64)
153
154#define CHECK_FETCH_FUNCS(method, fn) \
155 (((FETCH_FUNC_NAME(method, u8) == fn) || \
156 (FETCH_FUNC_NAME(method, u16) == fn) || \
157 (FETCH_FUNC_NAME(method, u32) == fn) || \
158 (FETCH_FUNC_NAME(method, u64) == fn) || \
159 (FETCH_FUNC_NAME(method, string) == fn) || \
160 (FETCH_FUNC_NAME(method, string_size) == fn)) \
161 && (fn != NULL))
162
163/* Data fetch function templates */
164#define DEFINE_FETCH_reg(type) \
165static __kprobes void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, \
166 void *offset, void *dest) \
167{ \
168 *(type *)dest = (type)regs_get_register(regs, \
169 (unsigned int)((unsigned long)offset)); \
170}
171DEFINE_BASIC_FETCH_FUNCS(reg)
172/* No string on the register */
173#define fetch_reg_string NULL
174#define fetch_reg_string_size NULL
175
176#define DEFINE_FETCH_stack(type) \
177static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
178 void *offset, void *dest) \
179{ \
180 *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
181 (unsigned int)((unsigned long)offset)); \
182}
183DEFINE_BASIC_FETCH_FUNCS(stack)
184/* No string on the stack entry */
185#define fetch_stack_string NULL
186#define fetch_stack_string_size NULL
187
188#define DEFINE_FETCH_retval(type) \
189static __kprobes void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,\
190 void *dummy, void *dest) \
191{ \
192 *(type *)dest = (type)regs_return_value(regs); \
193}
194DEFINE_BASIC_FETCH_FUNCS(retval)
195/* No string on the retval */
196#define fetch_retval_string NULL
197#define fetch_retval_string_size NULL
198
199#define DEFINE_FETCH_memory(type) \
200static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
201 void *addr, void *dest) \
202{ \
203 type retval; \
204 if (probe_kernel_address(addr, retval)) \
205 *(type *)dest = 0; \
206 else \
207 *(type *)dest = retval; \
208}
209DEFINE_BASIC_FETCH_FUNCS(memory)
210/*
211 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
212 * length and relative data location.
213 */
214static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
215 void *addr, void *dest)
216{
217 long ret;
218 int maxlen = get_rloc_len(*(u32 *)dest);
219 u8 *dst = get_rloc_data(dest);
220 u8 *src = addr;
221 mm_segment_t old_fs = get_fs();
222 if (!maxlen)
223 return;
224 /*
225 * Try to get string again, since the string can be changed while
226 * probing.
227 */
228 set_fs(KERNEL_DS);
229 pagefault_disable();
230 do
231 ret = __copy_from_user_inatomic(dst++, src++, 1);
232 while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
233 dst[-1] = '\0';
234 pagefault_enable();
235 set_fs(old_fs);
236
237 if (ret < 0) { /* Failed to fetch string */
238 ((u8 *)get_rloc_data(dest))[0] = '\0';
239 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
240 } else
241 *(u32 *)dest = make_data_rloc(src - (u8 *)addr,
242 get_rloc_offs(*(u32 *)dest));
243}
244/* Return the length of string -- including null terminal byte */
245static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
246 void *addr, void *dest)
247{
248 int ret, len = 0;
249 u8 c;
250 mm_segment_t old_fs = get_fs();
251
252 set_fs(KERNEL_DS);
253 pagefault_disable();
254 do {
255 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
256 len++;
257 } while (c && ret == 0 && len < MAX_STRING_SIZE);
258 pagefault_enable();
259 set_fs(old_fs);
260
261 if (ret < 0) /* Failed to check the length */
262 *(u32 *)dest = 0;
263 else
264 *(u32 *)dest = len;
265}
266
267/* Memory fetching by symbol */
268struct symbol_cache {
269 char *symbol;
270 long offset;
271 unsigned long addr;
272};
273
274static unsigned long update_symbol_cache(struct symbol_cache *sc)
275{
276 sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
277 if (sc->addr)
278 sc->addr += sc->offset;
279 return sc->addr;
280}
281
282static void free_symbol_cache(struct symbol_cache *sc)
283{
284 kfree(sc->symbol);
285 kfree(sc);
286}
287
288static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
289{
290 struct symbol_cache *sc;
291
292 if (!sym || strlen(sym) == 0)
293 return NULL;
294 sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
295 if (!sc)
296 return NULL;
297
298 sc->symbol = kstrdup(sym, GFP_KERNEL);
299 if (!sc->symbol) {
300 kfree(sc);
301 return NULL;
302 }
303 sc->offset = offset;
304
305 update_symbol_cache(sc);
306 return sc;
307}
308
309#define DEFINE_FETCH_symbol(type) \
310static __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,\
311 void *data, void *dest) \
312{ \
313 struct symbol_cache *sc = data; \
314 if (sc->addr) \
315 fetch_memory_##type(regs, (void *)sc->addr, dest); \
316 else \
317 *(type *)dest = 0; \
318}
319DEFINE_BASIC_FETCH_FUNCS(symbol)
320DEFINE_FETCH_symbol(string)
321DEFINE_FETCH_symbol(string_size)
322
323/* Dereference memory access function */
324struct deref_fetch_param {
325 struct fetch_param orig;
326 long offset;
327};
328
329#define DEFINE_FETCH_deref(type) \
330static __kprobes void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,\
331 void *data, void *dest) \
332{ \
333 struct deref_fetch_param *dprm = data; \
334 unsigned long addr; \
335 call_fetch(&dprm->orig, regs, &addr); \
336 if (addr) { \
337 addr += dprm->offset; \
338 fetch_memory_##type(regs, (void *)addr, dest); \
339 } else \
340 *(type *)dest = 0; \
341}
342DEFINE_BASIC_FETCH_FUNCS(deref)
343DEFINE_FETCH_deref(string)
344DEFINE_FETCH_deref(string_size)
345
346static __kprobes void update_deref_fetch_param(struct deref_fetch_param *data)
347{
348 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
349 update_deref_fetch_param(data->orig.data);
350 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
351 update_symbol_cache(data->orig.data);
352}
353
354static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)
355{
356 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
357 free_deref_fetch_param(data->orig.data);
358 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
359 free_symbol_cache(data->orig.data);
360 kfree(data);
361}
362
363/* Bitfield fetch function */
364struct bitfield_fetch_param {
365 struct fetch_param orig;
366 unsigned char hi_shift;
367 unsigned char low_shift;
368};
369
370#define DEFINE_FETCH_bitfield(type) \
371static __kprobes void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,\
372 void *data, void *dest) \
373{ \
374 struct bitfield_fetch_param *bprm = data; \
375 type buf = 0; \
376 call_fetch(&bprm->orig, regs, &buf); \
377 if (buf) { \
378 buf <<= bprm->hi_shift; \
379 buf >>= bprm->low_shift; \
380 } \
381 *(type *)dest = buf; \
382}
383DEFINE_BASIC_FETCH_FUNCS(bitfield)
384#define fetch_bitfield_string NULL
385#define fetch_bitfield_string_size NULL
386
387static __kprobes void
388update_bitfield_fetch_param(struct bitfield_fetch_param *data)
389{
390 /*
391 * Don't check the bitfield itself, because this must be the
392 * last fetch function.
393 */
394 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
395 update_deref_fetch_param(data->orig.data);
396 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
397 update_symbol_cache(data->orig.data);
398}
399
400static __kprobes void
401free_bitfield_fetch_param(struct bitfield_fetch_param *data)
402{
403 /*
404 * Don't check the bitfield itself, because this must be the
405 * last fetch function.
406 */
407 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
408 free_deref_fetch_param(data->orig.data);
409 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
410 free_symbol_cache(data->orig.data);
411 kfree(data);
412}
413
414/* Default (unsigned long) fetch type */
415#define __DEFAULT_FETCH_TYPE(t) u##t
416#define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
417#define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
418#define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
419
420/* Fetch types */
421enum {
422 FETCH_MTD_reg = 0,
423 FETCH_MTD_stack,
424 FETCH_MTD_retval,
425 FETCH_MTD_memory,
426 FETCH_MTD_symbol,
427 FETCH_MTD_deref,
428 FETCH_MTD_bitfield,
429 FETCH_MTD_END,
430};
431
432#define ASSIGN_FETCH_FUNC(method, type) \
433 [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
434
435#define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
436 {.name = _name, \
437 .size = _size, \
438 .is_signed = sign, \
439 .print = PRINT_TYPE_FUNC_NAME(ptype), \
440 .fmt = PRINT_TYPE_FMT_NAME(ptype), \
441 .fmttype = _fmttype, \
442 .fetch = { \
443ASSIGN_FETCH_FUNC(reg, ftype), \
444ASSIGN_FETCH_FUNC(stack, ftype), \
445ASSIGN_FETCH_FUNC(retval, ftype), \
446ASSIGN_FETCH_FUNC(memory, ftype), \
447ASSIGN_FETCH_FUNC(symbol, ftype), \
448ASSIGN_FETCH_FUNC(deref, ftype), \
449ASSIGN_FETCH_FUNC(bitfield, ftype), \
450 } \
451 }
452
453#define ASSIGN_FETCH_TYPE(ptype, ftype, sign) \
454 __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
455
456#define FETCH_TYPE_STRING 0
457#define FETCH_TYPE_STRSIZE 1
458
459/* Fetch type information table */
460static const struct fetch_type {
461 const char *name; /* Name of type */
462 size_t size; /* Byte size of type */
463 int is_signed; /* Signed flag */
464 print_type_func_t print; /* Print functions */
465 const char *fmt; /* Fromat string */
466 const char *fmttype; /* Name in format file */
467 /* Fetch functions */
468 fetch_func_t fetch[FETCH_MTD_END];
469} fetch_type_table[] = {
470 /* Special types */
471 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
472 sizeof(u32), 1, "__data_loc char[]"),
473 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
474 string_size, sizeof(u32), 0, "u32"),
475 /* Basic types */
476 ASSIGN_FETCH_TYPE(u8, u8, 0),
477 ASSIGN_FETCH_TYPE(u16, u16, 0),
478 ASSIGN_FETCH_TYPE(u32, u32, 0),
479 ASSIGN_FETCH_TYPE(u64, u64, 0),
480 ASSIGN_FETCH_TYPE(s8, u8, 1),
481 ASSIGN_FETCH_TYPE(s16, u16, 1),
482 ASSIGN_FETCH_TYPE(s32, u32, 1),
483 ASSIGN_FETCH_TYPE(s64, u64, 1),
484};
485
486static const struct fetch_type *find_fetch_type(const char *type)
487{
488 int i;
489
490 if (!type)
491 type = DEFAULT_FETCH_TYPE_STR;
492
493 /* Special case: bitfield */
494 if (*type == 'b') {
495 unsigned long bs;
496 type = strchr(type, '/');
497 if (!type)
498 goto fail;
499 type++;
500 if (strict_strtoul(type, 0, &bs))
501 goto fail;
502 switch (bs) {
503 case 8:
504 return find_fetch_type("u8");
505 case 16:
506 return find_fetch_type("u16");
507 case 32:
508 return find_fetch_type("u32");
509 case 64:
510 return find_fetch_type("u64");
511 default:
512 goto fail;
513 }
514 }
515
516 for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
517 if (strcmp(type, fetch_type_table[i].name) == 0)
518 return &fetch_type_table[i];
519fail:
520 return NULL;
521}
522
523/* Special function : only accept unsigned long */
524static __kprobes void fetch_stack_address(struct pt_regs *regs,
525 void *dummy, void *dest)
526{
527 *(unsigned long *)dest = kernel_stack_pointer(regs);
528}
529
530static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
531 fetch_func_t orig_fn)
532{
533 int i;
534
535 if (type != &fetch_type_table[FETCH_TYPE_STRING])
536 return NULL; /* Only string type needs size function */
537 for (i = 0; i < FETCH_MTD_END; i++)
538 if (type->fetch[i] == orig_fn)
539 return fetch_type_table[FETCH_TYPE_STRSIZE].fetch[i];
540
541 WARN_ON(1); /* This should not happen */
542 return NULL;
543}
544
545/**
546 * Kprobe event core functions
547 */
548
549struct probe_arg {
550 struct fetch_param fetch;
551 struct fetch_param fetch_size;
552 unsigned int offset; /* Offset from argument entry */
553 const char *name; /* Name of this argument */
554 const char *comm; /* Command of this argument */
555 const struct fetch_type *type; /* Type of this argument */
556};
557
558/* Flags for trace_probe */
559#define TP_FLAG_TRACE 1
560#define TP_FLAG_PROFILE 2
561#define TP_FLAG_REGISTERED 4
562
563struct trace_probe {
564 struct list_head list;
565 struct kretprobe rp; /* Use rp.kp for kprobe use */
566 unsigned long nhit;
567 unsigned int flags; /* For TP_FLAG_* */
568 const char *symbol; /* symbol name */
569 struct ftrace_event_class class;
570 struct ftrace_event_call call;
571 ssize_t size; /* trace entry size */
572 unsigned int nr_args;
573 struct probe_arg args[];
574};
575
576#define SIZEOF_TRACE_PROBE(n) \
577 (offsetof(struct trace_probe, args) + \
578 (sizeof(struct probe_arg) * (n)))
579
580
581static __kprobes int trace_probe_is_return(struct trace_probe *tp)
582{
583 return tp->rp.handler != NULL;
584}
585
586static __kprobes const char *trace_probe_symbol(struct trace_probe *tp)
587{
588 return tp->symbol ? tp->symbol : "unknown";
589}
590
591static __kprobes unsigned long trace_probe_offset(struct trace_probe *tp)
592{
593 return tp->rp.kp.offset;
594}
595
596static __kprobes bool trace_probe_is_enabled(struct trace_probe *tp)
597{
598 return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
599}
600
601static __kprobes bool trace_probe_is_registered(struct trace_probe *tp)
602{
603 return !!(tp->flags & TP_FLAG_REGISTERED);
604}
605
606static __kprobes bool trace_probe_has_gone(struct trace_probe *tp)
607{
608 return !!(kprobe_gone(&tp->rp.kp));
609}
610
611static __kprobes bool trace_probe_within_module(struct trace_probe *tp,
612 struct module *mod)
613{
614 int len = strlen(mod->name);
615 const char *name = trace_probe_symbol(tp);
616 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
617}
618
619static __kprobes bool trace_probe_is_on_module(struct trace_probe *tp)
620{
621 return !!strchr(trace_probe_symbol(tp), ':');
622}
623
624static int register_probe_event(struct trace_probe *tp);
625static void unregister_probe_event(struct trace_probe *tp);
626
627static DEFINE_MUTEX(probe_lock);
628static LIST_HEAD(probe_list);
629
630static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
631static int kretprobe_dispatcher(struct kretprobe_instance *ri,
632 struct pt_regs *regs);
633
634/* Check the name is good for event/group/fields */
635static int is_good_name(const char *name)
636{
637 if (!isalpha(*name) && *name != '_')
638 return 0;
639 while (*++name != '\0') {
640 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
641 return 0;
642 }
643 return 1;
644}
645
646/*
647 * Allocate new trace_probe and initialize it (including kprobes).
648 */
649static struct trace_probe *alloc_trace_probe(const char *group,
650 const char *event,
651 void *addr,
652 const char *symbol,
653 unsigned long offs,
654 int nargs, int is_return)
655{
656 struct trace_probe *tp;
657 int ret = -ENOMEM;
658
659 tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
660 if (!tp)
661 return ERR_PTR(ret);
662
663 if (symbol) {
664 tp->symbol = kstrdup(symbol, GFP_KERNEL);
665 if (!tp->symbol)
666 goto error;
667 tp->rp.kp.symbol_name = tp->symbol;
668 tp->rp.kp.offset = offs;
669 } else
670 tp->rp.kp.addr = addr;
671
672 if (is_return)
673 tp->rp.handler = kretprobe_dispatcher;
674 else
675 tp->rp.kp.pre_handler = kprobe_dispatcher;
676
677 if (!event || !is_good_name(event)) {
678 ret = -EINVAL;
679 goto error;
680 }
681
682 tp->call.class = &tp->class;
683 tp->call.name = kstrdup(event, GFP_KERNEL);
684 if (!tp->call.name)
685 goto error;
686
687 if (!group || !is_good_name(group)) {
688 ret = -EINVAL;
689 goto error;
690 }
691
692 tp->class.system = kstrdup(group, GFP_KERNEL);
693 if (!tp->class.system)
694 goto error;
695
696 INIT_LIST_HEAD(&tp->list);
697 return tp;
698error:
699 kfree(tp->call.name);
700 kfree(tp->symbol);
701 kfree(tp);
702 return ERR_PTR(ret);
703}
704
705static void update_probe_arg(struct probe_arg *arg)
706{
707 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
708 update_bitfield_fetch_param(arg->fetch.data);
709 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
710 update_deref_fetch_param(arg->fetch.data);
711 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
712 update_symbol_cache(arg->fetch.data);
713}
714
715static void free_probe_arg(struct probe_arg *arg)
716{
717 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
718 free_bitfield_fetch_param(arg->fetch.data);
719 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
720 free_deref_fetch_param(arg->fetch.data);
721 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
722 free_symbol_cache(arg->fetch.data);
723 kfree(arg->name);
724 kfree(arg->comm);
725}
726
727static void free_trace_probe(struct trace_probe *tp)
728{
729 int i;
730
731 for (i = 0; i < tp->nr_args; i++)
732 free_probe_arg(&tp->args[i]);
733
734 kfree(tp->call.class->system);
735 kfree(tp->call.name);
736 kfree(tp->symbol);
737 kfree(tp);
738}
739
740static struct trace_probe *find_trace_probe(const char *event,
741 const char *group)
742{
743 struct trace_probe *tp;
744
745 list_for_each_entry(tp, &probe_list, list)
746 if (strcmp(tp->call.name, event) == 0 &&
747 strcmp(tp->call.class->system, group) == 0)
748 return tp;
749 return NULL;
750}
751
752/* Enable trace_probe - @flag must be TP_FLAG_TRACE or TP_FLAG_PROFILE */
753static int enable_trace_probe(struct trace_probe *tp, int flag)
754{
755 int ret = 0;
756
757 tp->flags |= flag;
758 if (trace_probe_is_enabled(tp) && trace_probe_is_registered(tp) &&
759 !trace_probe_has_gone(tp)) {
760 if (trace_probe_is_return(tp))
761 ret = enable_kretprobe(&tp->rp);
762 else
763 ret = enable_kprobe(&tp->rp.kp);
764 }
765
766 return ret;
767}
768
769/* Disable trace_probe - @flag must be TP_FLAG_TRACE or TP_FLAG_PROFILE */
770static void disable_trace_probe(struct trace_probe *tp, int flag)
771{
772 tp->flags &= ~flag;
773 if (!trace_probe_is_enabled(tp) && trace_probe_is_registered(tp)) {
774 if (trace_probe_is_return(tp))
775 disable_kretprobe(&tp->rp);
776 else
777 disable_kprobe(&tp->rp.kp);
778 }
779}
780
781/* Internal register function - just handle k*probes and flags */
782static int __register_trace_probe(struct trace_probe *tp)
783{
784 int i, ret;
785
786 if (trace_probe_is_registered(tp))
787 return -EINVAL;
788
789 for (i = 0; i < tp->nr_args; i++)
790 update_probe_arg(&tp->args[i]);
791
792 /* Set/clear disabled flag according to tp->flag */
793 if (trace_probe_is_enabled(tp))
794 tp->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
795 else
796 tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
797
798 if (trace_probe_is_return(tp))
799 ret = register_kretprobe(&tp->rp);
800 else
801 ret = register_kprobe(&tp->rp.kp);
802
803 if (ret == 0)
804 tp->flags |= TP_FLAG_REGISTERED;
805 else {
806 pr_warning("Could not insert probe at %s+%lu: %d\n",
807 trace_probe_symbol(tp), trace_probe_offset(tp), ret);
808 if (ret == -ENOENT && trace_probe_is_on_module(tp)) {
809 pr_warning("This probe might be able to register after"
810 "target module is loaded. Continue.\n");
811 ret = 0;
812 } else if (ret == -EILSEQ) {
813 pr_warning("Probing address(0x%p) is not an "
814 "instruction boundary.\n",
815 tp->rp.kp.addr);
816 ret = -EINVAL;
817 }
818 }
819
820 return ret;
821}
822
823/* Internal unregister function - just handle k*probes and flags */
824static void __unregister_trace_probe(struct trace_probe *tp)
825{
826 if (trace_probe_is_registered(tp)) {
827 if (trace_probe_is_return(tp))
828 unregister_kretprobe(&tp->rp);
829 else
830 unregister_kprobe(&tp->rp.kp);
831 tp->flags &= ~TP_FLAG_REGISTERED;
832 /* Cleanup kprobe for reuse */
833 if (tp->rp.kp.symbol_name)
834 tp->rp.kp.addr = NULL;
835 }
836}
837
838/* Unregister a trace_probe and probe_event: call with locking probe_lock */
839static void unregister_trace_probe(struct trace_probe *tp)
840{
841 __unregister_trace_probe(tp);
842 list_del(&tp->list);
843 unregister_probe_event(tp);
844}
845
846/* Register a trace_probe and probe_event */
847static int register_trace_probe(struct trace_probe *tp)
848{
849 struct trace_probe *old_tp;
850 int ret;
851
852 mutex_lock(&probe_lock);
853
854 /* Delete old (same name) event if exist */
855 old_tp = find_trace_probe(tp->call.name, tp->call.class->system);
856 if (old_tp) {
857 unregister_trace_probe(old_tp);
858 free_trace_probe(old_tp);
859 }
860
861 /* Register new event */
862 ret = register_probe_event(tp);
863 if (ret) {
864 pr_warning("Failed to register probe event(%d)\n", ret);
865 goto end;
866 }
867
868 /* Register k*probe */
869 ret = __register_trace_probe(tp);
870 if (ret < 0)
871 unregister_probe_event(tp);
872 else
873 list_add_tail(&tp->list, &probe_list);
874
875end:
876 mutex_unlock(&probe_lock);
877 return ret;
878}
879
880/* Module notifier call back, checking event on the module */
881static int trace_probe_module_callback(struct notifier_block *nb,
882 unsigned long val, void *data)
883{
884 struct module *mod = data;
885 struct trace_probe *tp;
886 int ret;
887
888 if (val != MODULE_STATE_COMING)
889 return NOTIFY_DONE;
890
891 /* Update probes on coming module */
892 mutex_lock(&probe_lock);
893 list_for_each_entry(tp, &probe_list, list) {
894 if (trace_probe_within_module(tp, mod)) {
895 __unregister_trace_probe(tp);
896 ret = __register_trace_probe(tp);
897 if (ret)
898 pr_warning("Failed to re-register probe %s on"
899 "%s: %d\n",
900 tp->call.name, mod->name, ret);
901 }
902 }
903 mutex_unlock(&probe_lock);
904
905 return NOTIFY_DONE;
906}
907
908static struct notifier_block trace_probe_module_nb = {
909 .notifier_call = trace_probe_module_callback,
910 .priority = 1 /* Invoked after kprobe module callback */
911};
912
913/* Split symbol and offset. */
914static int split_symbol_offset(char *symbol, unsigned long *offset)
915{
916 char *tmp;
917 int ret;
918
919 if (!offset)
920 return -EINVAL;
921
922 tmp = strchr(symbol, '+');
923 if (tmp) {
924 /* skip sign because strict_strtol doesn't accept '+' */
925 ret = strict_strtoul(tmp + 1, 0, offset);
926 if (ret)
927 return ret;
928 *tmp = '\0';
929 } else
930 *offset = 0;
931 return 0;
932}
933
934#define PARAM_MAX_ARGS 16
935#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
936
937static int parse_probe_vars(char *arg, const struct fetch_type *t,
938 struct fetch_param *f, int is_return)
939{
940 int ret = 0;
941 unsigned long param;
942
943 if (strcmp(arg, "retval") == 0) {
944 if (is_return)
945 f->fn = t->fetch[FETCH_MTD_retval];
946 else
947 ret = -EINVAL;
948 } else if (strncmp(arg, "stack", 5) == 0) {
949 if (arg[5] == '\0') {
950 if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
951 f->fn = fetch_stack_address;
952 else
953 ret = -EINVAL;
954 } else if (isdigit(arg[5])) {
955 ret = strict_strtoul(arg + 5, 10, ¶m);
956 if (ret || param > PARAM_MAX_STACK)
957 ret = -EINVAL;
958 else {
959 f->fn = t->fetch[FETCH_MTD_stack];
960 f->data = (void *)param;
961 }
962 } else
963 ret = -EINVAL;
964 } else
965 ret = -EINVAL;
966 return ret;
967}
968
969/* Recursive argument parser */
970static int __parse_probe_arg(char *arg, const struct fetch_type *t,
971 struct fetch_param *f, int is_return)
972{
973 int ret = 0;
974 unsigned long param;
975 long offset;
976 char *tmp;
977
978 switch (arg[0]) {
979 case '$':
980 ret = parse_probe_vars(arg + 1, t, f, is_return);
981 break;
982 case '%': /* named register */
983 ret = regs_query_register_offset(arg + 1);
984 if (ret >= 0) {
985 f->fn = t->fetch[FETCH_MTD_reg];
986 f->data = (void *)(unsigned long)ret;
987 ret = 0;
988 }
989 break;
990 case '@': /* memory or symbol */
991 if (isdigit(arg[1])) {
992 ret = strict_strtoul(arg + 1, 0, ¶m);
993 if (ret)
994 break;
995 f->fn = t->fetch[FETCH_MTD_memory];
996 f->data = (void *)param;
997 } else {
998 ret = split_symbol_offset(arg + 1, &offset);
999 if (ret)
1000 break;
1001 f->data = alloc_symbol_cache(arg + 1, offset);
1002 if (f->data)
1003 f->fn = t->fetch[FETCH_MTD_symbol];
1004 }
1005 break;
1006 case '+': /* deref memory */
1007 arg++; /* Skip '+', because strict_strtol() rejects it. */
1008 case '-':
1009 tmp = strchr(arg, '(');
1010 if (!tmp)
1011 break;
1012 *tmp = '\0';
1013 ret = strict_strtol(arg, 0, &offset);
1014 if (ret)
1015 break;
1016 arg = tmp + 1;
1017 tmp = strrchr(arg, ')');
1018 if (tmp) {
1019 struct deref_fetch_param *dprm;
1020 const struct fetch_type *t2 = find_fetch_type(NULL);
1021 *tmp = '\0';
1022 dprm = kzalloc(sizeof(struct deref_fetch_param),
1023 GFP_KERNEL);
1024 if (!dprm)
1025 return -ENOMEM;
1026 dprm->offset = offset;
1027 ret = __parse_probe_arg(arg, t2, &dprm->orig,
1028 is_return);
1029 if (ret)
1030 kfree(dprm);
1031 else {
1032 f->fn = t->fetch[FETCH_MTD_deref];
1033 f->data = (void *)dprm;
1034 }
1035 }
1036 break;
1037 }
1038 if (!ret && !f->fn) { /* Parsed, but do not find fetch method */
1039 pr_info("%s type has no corresponding fetch method.\n",
1040 t->name);
1041 ret = -EINVAL;
1042 }
1043 return ret;
1044}
1045
1046#define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
1047
1048/* Bitfield type needs to be parsed into a fetch function */
1049static int __parse_bitfield_probe_arg(const char *bf,
1050 const struct fetch_type *t,
1051 struct fetch_param *f)
1052{
1053 struct bitfield_fetch_param *bprm;
1054 unsigned long bw, bo;
1055 char *tail;
1056
1057 if (*bf != 'b')
1058 return 0;
1059
1060 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
1061 if (!bprm)
1062 return -ENOMEM;
1063 bprm->orig = *f;
1064 f->fn = t->fetch[FETCH_MTD_bitfield];
1065 f->data = (void *)bprm;
1066
1067 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
1068 if (bw == 0 || *tail != '@')
1069 return -EINVAL;
1070
1071 bf = tail + 1;
1072 bo = simple_strtoul(bf, &tail, 0);
1073 if (tail == bf || *tail != '/')
1074 return -EINVAL;
1075
1076 bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
1077 bprm->low_shift = bprm->hi_shift + bo;
1078 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
1079}
1080
1081/* String length checking wrapper */
1082static int parse_probe_arg(char *arg, struct trace_probe *tp,
1083 struct probe_arg *parg, int is_return)
1084{
1085 const char *t;
1086 int ret;
1087
1088 if (strlen(arg) > MAX_ARGSTR_LEN) {
1089 pr_info("Argument is too long.: %s\n", arg);
1090 return -ENOSPC;
1091 }
1092 parg->comm = kstrdup(arg, GFP_KERNEL);
1093 if (!parg->comm) {
1094 pr_info("Failed to allocate memory for command '%s'.\n", arg);
1095 return -ENOMEM;
1096 }
1097 t = strchr(parg->comm, ':');
1098 if (t) {
1099 arg[t - parg->comm] = '\0';
1100 t++;
1101 }
1102 parg->type = find_fetch_type(t);
1103 if (!parg->type) {
1104 pr_info("Unsupported type: %s\n", t);
1105 return -EINVAL;
1106 }
1107 parg->offset = tp->size;
1108 tp->size += parg->type->size;
1109 ret = __parse_probe_arg(arg, parg->type, &parg->fetch, is_return);
1110 if (ret >= 0 && t != NULL)
1111 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
1112 if (ret >= 0) {
1113 parg->fetch_size.fn = get_fetch_size_function(parg->type,
1114 parg->fetch.fn);
1115 parg->fetch_size.data = parg->fetch.data;
1116 }
1117 return ret;
1118}
1119
1120/* Return 1 if name is reserved or already used by another argument */
1121static int conflict_field_name(const char *name,
1122 struct probe_arg *args, int narg)
1123{
1124 int i;
1125 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1126 if (strcmp(reserved_field_names[i], name) == 0)
1127 return 1;
1128 for (i = 0; i < narg; i++)
1129 if (strcmp(args[i].name, name) == 0)
1130 return 1;
1131 return 0;
1132}
1133
1134static int create_trace_probe(int argc, char **argv)
1135{
1136 /*
1137 * Argument syntax:
1138 * - Add kprobe: p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
1139 * - Add kretprobe: r[:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
1140 * Fetch args:
1141 * $retval : fetch return value
1142 * $stack : fetch stack address
1143 * $stackN : fetch Nth of stack (N:0-)
1144 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
1145 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
1146 * %REG : fetch register REG
1147 * Dereferencing memory fetch:
1148 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
1149 * Alias name of args:
1150 * NAME=FETCHARG : set NAME as alias of FETCHARG.
1151 * Type of args:
1152 * FETCHARG:TYPE : use TYPE instead of unsigned long.
1153 */
1154 struct trace_probe *tp;
1155 int i, ret = 0;
1156 int is_return = 0, is_delete = 0;
1157 char *symbol = NULL, *event = NULL, *group = NULL;
1158 char *arg;
1159 unsigned long offset = 0;
1160 void *addr = NULL;
1161 char buf[MAX_EVENT_NAME_LEN];
1162
1163 /* argc must be >= 1 */
1164 if (argv[0][0] == 'p')
1165 is_return = 0;
1166 else if (argv[0][0] == 'r')
1167 is_return = 1;
1168 else if (argv[0][0] == '-')
1169 is_delete = 1;
1170 else {
1171 pr_info("Probe definition must be started with 'p', 'r' or"
1172 " '-'.\n");
1173 return -EINVAL;
1174 }
1175
1176 if (argv[0][1] == ':') {
1177 event = &argv[0][2];
1178 if (strchr(event, '/')) {
1179 group = event;
1180 event = strchr(group, '/') + 1;
1181 event[-1] = '\0';
1182 if (strlen(group) == 0) {
1183 pr_info("Group name is not specified\n");
1184 return -EINVAL;
1185 }
1186 }
1187 if (strlen(event) == 0) {
1188 pr_info("Event name is not specified\n");
1189 return -EINVAL;
1190 }
1191 }
1192 if (!group)
1193 group = KPROBE_EVENT_SYSTEM;
1194
1195 if (is_delete) {
1196 if (!event) {
1197 pr_info("Delete command needs an event name.\n");
1198 return -EINVAL;
1199 }
1200 mutex_lock(&probe_lock);
1201 tp = find_trace_probe(event, group);
1202 if (!tp) {
1203 mutex_unlock(&probe_lock);
1204 pr_info("Event %s/%s doesn't exist.\n", group, event);
1205 return -ENOENT;
1206 }
1207 /* delete an event */
1208 unregister_trace_probe(tp);
1209 free_trace_probe(tp);
1210 mutex_unlock(&probe_lock);
1211 return 0;
1212 }
1213
1214 if (argc < 2) {
1215 pr_info("Probe point is not specified.\n");
1216 return -EINVAL;
1217 }
1218 if (isdigit(argv[1][0])) {
1219 if (is_return) {
1220 pr_info("Return probe point must be a symbol.\n");
1221 return -EINVAL;
1222 }
1223 /* an address specified */
1224 ret = strict_strtoul(&argv[1][0], 0, (unsigned long *)&addr);
1225 if (ret) {
1226 pr_info("Failed to parse address.\n");
1227 return ret;
1228 }
1229 } else {
1230 /* a symbol specified */
1231 symbol = argv[1];
1232 /* TODO: support .init module functions */
1233 ret = split_symbol_offset(symbol, &offset);
1234 if (ret) {
1235 pr_info("Failed to parse symbol.\n");
1236 return ret;
1237 }
1238 if (offset && is_return) {
1239 pr_info("Return probe must be used without offset.\n");
1240 return -EINVAL;
1241 }
1242 }
1243 argc -= 2; argv += 2;
1244
1245 /* setup a probe */
1246 if (!event) {
1247 /* Make a new event name */
1248 if (symbol)
1249 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
1250 is_return ? 'r' : 'p', symbol, offset);
1251 else
1252 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
1253 is_return ? 'r' : 'p', addr);
1254 event = buf;
1255 }
1256 tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
1257 is_return);
1258 if (IS_ERR(tp)) {
1259 pr_info("Failed to allocate trace_probe.(%d)\n",
1260 (int)PTR_ERR(tp));
1261 return PTR_ERR(tp);
1262 }
1263
1264 /* parse arguments */
1265 ret = 0;
1266 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
1267 /* Increment count for freeing args in error case */
1268 tp->nr_args++;
1269
1270 /* Parse argument name */
1271 arg = strchr(argv[i], '=');
1272 if (arg) {
1273 *arg++ = '\0';
1274 tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
1275 } else {
1276 arg = argv[i];
1277 /* If argument name is omitted, set "argN" */
1278 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
1279 tp->args[i].name = kstrdup(buf, GFP_KERNEL);
1280 }
1281
1282 if (!tp->args[i].name) {
1283 pr_info("Failed to allocate argument[%d] name.\n", i);
1284 ret = -ENOMEM;
1285 goto error;
1286 }
1287
1288 if (!is_good_name(tp->args[i].name)) {
1289 pr_info("Invalid argument[%d] name: %s\n",
1290 i, tp->args[i].name);
1291 ret = -EINVAL;
1292 goto error;
1293 }
1294
1295 if (conflict_field_name(tp->args[i].name, tp->args, i)) {
1296 pr_info("Argument[%d] name '%s' conflicts with "
1297 "another field.\n", i, argv[i]);
1298 ret = -EINVAL;
1299 goto error;
1300 }
1301
1302 /* Parse fetch argument */
1303 ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
1304 if (ret) {
1305 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
1306 goto error;
1307 }
1308 }
1309
1310 ret = register_trace_probe(tp);
1311 if (ret)
1312 goto error;
1313 return 0;
1314
1315error:
1316 free_trace_probe(tp);
1317 return ret;
1318}
1319
1320static void release_all_trace_probes(void)
1321{
1322 struct trace_probe *tp;
1323
1324 mutex_lock(&probe_lock);
1325 /* TODO: Use batch unregistration */
1326 while (!list_empty(&probe_list)) {
1327 tp = list_entry(probe_list.next, struct trace_probe, list);
1328 unregister_trace_probe(tp);
1329 free_trace_probe(tp);
1330 }
1331 mutex_unlock(&probe_lock);
1332}
1333
1334/* Probes listing interfaces */
1335static void *probes_seq_start(struct seq_file *m, loff_t *pos)
1336{
1337 mutex_lock(&probe_lock);
1338 return seq_list_start(&probe_list, *pos);
1339}
1340
1341static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
1342{
1343 return seq_list_next(v, &probe_list, pos);
1344}
1345
1346static void probes_seq_stop(struct seq_file *m, void *v)
1347{
1348 mutex_unlock(&probe_lock);
1349}
1350
1351static int probes_seq_show(struct seq_file *m, void *v)
1352{
1353 struct trace_probe *tp = v;
1354 int i;
1355
1356 seq_printf(m, "%c", trace_probe_is_return(tp) ? 'r' : 'p');
1357 seq_printf(m, ":%s/%s", tp->call.class->system, tp->call.name);
1358
1359 if (!tp->symbol)
1360 seq_printf(m, " 0x%p", tp->rp.kp.addr);
1361 else if (tp->rp.kp.offset)
1362 seq_printf(m, " %s+%u", trace_probe_symbol(tp),
1363 tp->rp.kp.offset);
1364 else
1365 seq_printf(m, " %s", trace_probe_symbol(tp));
1366
1367 for (i = 0; i < tp->nr_args; i++)
1368 seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
1369 seq_printf(m, "\n");
1370
1371 return 0;
1372}
1373
1374static const struct seq_operations probes_seq_op = {
1375 .start = probes_seq_start,
1376 .next = probes_seq_next,
1377 .stop = probes_seq_stop,
1378 .show = probes_seq_show
1379};
1380
1381static int probes_open(struct inode *inode, struct file *file)
1382{
1383 if ((file->f_mode & FMODE_WRITE) &&
1384 (file->f_flags & O_TRUNC))
1385 release_all_trace_probes();
1386
1387 return seq_open(file, &probes_seq_op);
1388}
1389
1390static int command_trace_probe(const char *buf)
1391{
1392 char **argv;
1393 int argc = 0, ret = 0;
1394
1395 argv = argv_split(GFP_KERNEL, buf, &argc);
1396 if (!argv)
1397 return -ENOMEM;
1398
1399 if (argc)
1400 ret = create_trace_probe(argc, argv);
1401
1402 argv_free(argv);
1403 return ret;
1404}
1405
1406#define WRITE_BUFSIZE 4096
1407
1408static ssize_t probes_write(struct file *file, const char __user *buffer,
1409 size_t count, loff_t *ppos)
1410{
1411 char *kbuf, *tmp;
1412 int ret;
1413 size_t done;
1414 size_t size;
1415
1416 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
1417 if (!kbuf)
1418 return -ENOMEM;
1419
1420 ret = done = 0;
1421 while (done < count) {
1422 size = count - done;
1423 if (size >= WRITE_BUFSIZE)
1424 size = WRITE_BUFSIZE - 1;
1425 if (copy_from_user(kbuf, buffer + done, size)) {
1426 ret = -EFAULT;
1427 goto out;
1428 }
1429 kbuf[size] = '\0';
1430 tmp = strchr(kbuf, '\n');
1431 if (tmp) {
1432 *tmp = '\0';
1433 size = tmp - kbuf + 1;
1434 } else if (done + size < count) {
1435 pr_warning("Line length is too long: "
1436 "Should be less than %d.", WRITE_BUFSIZE);
1437 ret = -EINVAL;
1438 goto out;
1439 }
1440 done += size;
1441 /* Remove comments */
1442 tmp = strchr(kbuf, '#');
1443 if (tmp)
1444 *tmp = '\0';
1445
1446 ret = command_trace_probe(kbuf);
1447 if (ret)
1448 goto out;
1449 }
1450 ret = done;
1451out:
1452 kfree(kbuf);
1453 return ret;
1454}
1455
1456static const struct file_operations kprobe_events_ops = {
1457 .owner = THIS_MODULE,
1458 .open = probes_open,
1459 .read = seq_read,
1460 .llseek = seq_lseek,
1461 .release = seq_release,
1462 .write = probes_write,
1463};
1464
1465/* Probes profiling interfaces */
1466static int probes_profile_seq_show(struct seq_file *m, void *v)
1467{
1468 struct trace_probe *tp = v;
1469
1470 seq_printf(m, " %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
1471 tp->rp.kp.nmissed);
1472
1473 return 0;
1474}
1475
1476static const struct seq_operations profile_seq_op = {
1477 .start = probes_seq_start,
1478 .next = probes_seq_next,
1479 .stop = probes_seq_stop,
1480 .show = probes_profile_seq_show
1481};
1482
1483static int profile_open(struct inode *inode, struct file *file)
1484{
1485 return seq_open(file, &profile_seq_op);
1486}
1487
1488static const struct file_operations kprobe_profile_ops = {
1489 .owner = THIS_MODULE,
1490 .open = profile_open,
1491 .read = seq_read,
1492 .llseek = seq_lseek,
1493 .release = seq_release,
1494};
1495
1496/* Sum up total data length for dynamic arraies (strings) */
1497static __kprobes int __get_data_size(struct trace_probe *tp,
1498 struct pt_regs *regs)
1499{
1500 int i, ret = 0;
1501 u32 len;
1502
1503 for (i = 0; i < tp->nr_args; i++)
1504 if (unlikely(tp->args[i].fetch_size.fn)) {
1505 call_fetch(&tp->args[i].fetch_size, regs, &len);
1506 ret += len;
1507 }
1508
1509 return ret;
1510}
1511
1512/* Store the value of each argument */
1513static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
1514 struct pt_regs *regs,
1515 u8 *data, int maxlen)
1516{
1517 int i;
1518 u32 end = tp->size;
1519 u32 *dl; /* Data (relative) location */
1520
1521 for (i = 0; i < tp->nr_args; i++) {
1522 if (unlikely(tp->args[i].fetch_size.fn)) {
1523 /*
1524 * First, we set the relative location and
1525 * maximum data length to *dl
1526 */
1527 dl = (u32 *)(data + tp->args[i].offset);
1528 *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
1529 /* Then try to fetch string or dynamic array data */
1530 call_fetch(&tp->args[i].fetch, regs, dl);
1531 /* Reduce maximum length */
1532 end += get_rloc_len(*dl);
1533 maxlen -= get_rloc_len(*dl);
1534 /* Trick here, convert data_rloc to data_loc */
1535 *dl = convert_rloc_to_loc(*dl,
1536 ent_size + tp->args[i].offset);
1537 } else
1538 /* Just fetching data normally */
1539 call_fetch(&tp->args[i].fetch, regs,
1540 data + tp->args[i].offset);
1541 }
1542}
1543
1544/* Kprobe handler */
1545static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
1546{
1547 struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1548 struct kprobe_trace_entry_head *entry;
1549 struct ring_buffer_event *event;
1550 struct ring_buffer *buffer;
1551 int size, dsize, pc;
1552 unsigned long irq_flags;
1553 struct ftrace_event_call *call = &tp->call;
1554
1555 tp->nhit++;
1556
1557 local_save_flags(irq_flags);
1558 pc = preempt_count();
1559
1560 dsize = __get_data_size(tp, regs);
1561 size = sizeof(*entry) + tp->size + dsize;
1562
1563 event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1564 size, irq_flags, pc);
1565 if (!event)
1566 return;
1567
1568 entry = ring_buffer_event_data(event);
1569 entry->ip = (unsigned long)kp->addr;
1570 store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1571
1572 if (!filter_current_check_discard(buffer, call, entry, event))
1573 trace_nowake_buffer_unlock_commit_regs(buffer, event,
1574 irq_flags, pc, regs);
1575}
1576
1577/* Kretprobe handler */
1578static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
1579 struct pt_regs *regs)
1580{
1581 struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1582 struct kretprobe_trace_entry_head *entry;
1583 struct ring_buffer_event *event;
1584 struct ring_buffer *buffer;
1585 int size, pc, dsize;
1586 unsigned long irq_flags;
1587 struct ftrace_event_call *call = &tp->call;
1588
1589 local_save_flags(irq_flags);
1590 pc = preempt_count();
1591
1592 dsize = __get_data_size(tp, regs);
1593 size = sizeof(*entry) + tp->size + dsize;
1594
1595 event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1596 size, irq_flags, pc);
1597 if (!event)
1598 return;
1599
1600 entry = ring_buffer_event_data(event);
1601 entry->func = (unsigned long)tp->rp.kp.addr;
1602 entry->ret_ip = (unsigned long)ri->ret_addr;
1603 store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1604
1605 if (!filter_current_check_discard(buffer, call, entry, event))
1606 trace_nowake_buffer_unlock_commit_regs(buffer, event,
1607 irq_flags, pc, regs);
1608}
1609
1610/* Event entry printers */
1611enum print_line_t
1612print_kprobe_event(struct trace_iterator *iter, int flags,
1613 struct trace_event *event)
1614{
1615 struct kprobe_trace_entry_head *field;
1616 struct trace_seq *s = &iter->seq;
1617 struct trace_probe *tp;
1618 u8 *data;
1619 int i;
1620
1621 field = (struct kprobe_trace_entry_head *)iter->ent;
1622 tp = container_of(event, struct trace_probe, call.event);
1623
1624 if (!trace_seq_printf(s, "%s: (", tp->call.name))
1625 goto partial;
1626
1627 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1628 goto partial;
1629
1630 if (!trace_seq_puts(s, ")"))
1631 goto partial;
1632
1633 data = (u8 *)&field[1];
1634 for (i = 0; i < tp->nr_args; i++)
1635 if (!tp->args[i].type->print(s, tp->args[i].name,
1636 data + tp->args[i].offset, field))
1637 goto partial;
1638
1639 if (!trace_seq_puts(s, "\n"))
1640 goto partial;
1641
1642 return TRACE_TYPE_HANDLED;
1643partial:
1644 return TRACE_TYPE_PARTIAL_LINE;
1645}
1646
1647enum print_line_t
1648print_kretprobe_event(struct trace_iterator *iter, int flags,
1649 struct trace_event *event)
1650{
1651 struct kretprobe_trace_entry_head *field;
1652 struct trace_seq *s = &iter->seq;
1653 struct trace_probe *tp;
1654 u8 *data;
1655 int i;
1656
1657 field = (struct kretprobe_trace_entry_head *)iter->ent;
1658 tp = container_of(event, struct trace_probe, call.event);
1659
1660 if (!trace_seq_printf(s, "%s: (", tp->call.name))
1661 goto partial;
1662
1663 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1664 goto partial;
1665
1666 if (!trace_seq_puts(s, " <- "))
1667 goto partial;
1668
1669 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1670 goto partial;
1671
1672 if (!trace_seq_puts(s, ")"))
1673 goto partial;
1674
1675 data = (u8 *)&field[1];
1676 for (i = 0; i < tp->nr_args; i++)
1677 if (!tp->args[i].type->print(s, tp->args[i].name,
1678 data + tp->args[i].offset, field))
1679 goto partial;
1680
1681 if (!trace_seq_puts(s, "\n"))
1682 goto partial;
1683
1684 return TRACE_TYPE_HANDLED;
1685partial:
1686 return TRACE_TYPE_PARTIAL_LINE;
1687}
1688
1689#undef DEFINE_FIELD
1690#define DEFINE_FIELD(type, item, name, is_signed) \
1691 do { \
1692 ret = trace_define_field(event_call, #type, name, \
1693 offsetof(typeof(field), item), \
1694 sizeof(field.item), is_signed, \
1695 FILTER_OTHER); \
1696 if (ret) \
1697 return ret; \
1698 } while (0)
1699
1700static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1701{
1702 int ret, i;
1703 struct kprobe_trace_entry_head field;
1704 struct trace_probe *tp = (struct trace_probe *)event_call->data;
1705
1706 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1707 /* Set argument names as fields */
1708 for (i = 0; i < tp->nr_args; i++) {
1709 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1710 tp->args[i].name,
1711 sizeof(field) + tp->args[i].offset,
1712 tp->args[i].type->size,
1713 tp->args[i].type->is_signed,
1714 FILTER_OTHER);
1715 if (ret)
1716 return ret;
1717 }
1718 return 0;
1719}
1720
1721static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1722{
1723 int ret, i;
1724 struct kretprobe_trace_entry_head field;
1725 struct trace_probe *tp = (struct trace_probe *)event_call->data;
1726
1727 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1728 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1729 /* Set argument names as fields */
1730 for (i = 0; i < tp->nr_args; i++) {
1731 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1732 tp->args[i].name,
1733 sizeof(field) + tp->args[i].offset,
1734 tp->args[i].type->size,
1735 tp->args[i].type->is_signed,
1736 FILTER_OTHER);
1737 if (ret)
1738 return ret;
1739 }
1740 return 0;
1741}
1742
1743static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
1744{
1745 int i;
1746 int pos = 0;
1747
1748 const char *fmt, *arg;
1749
1750 if (!trace_probe_is_return(tp)) {
1751 fmt = "(%lx)";
1752 arg = "REC->" FIELD_STRING_IP;
1753 } else {
1754 fmt = "(%lx <- %lx)";
1755 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1756 }
1757
1758 /* When len=0, we just calculate the needed length */
1759#define LEN_OR_ZERO (len ? len - pos : 0)
1760
1761 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1762
1763 for (i = 0; i < tp->nr_args; i++) {
1764 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
1765 tp->args[i].name, tp->args[i].type->fmt);
1766 }
1767
1768 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
1769
1770 for (i = 0; i < tp->nr_args; i++) {
1771 if (strcmp(tp->args[i].type->name, "string") == 0)
1772 pos += snprintf(buf + pos, LEN_OR_ZERO,
1773 ", __get_str(%s)",
1774 tp->args[i].name);
1775 else
1776 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
1777 tp->args[i].name);
1778 }
1779
1780#undef LEN_OR_ZERO
1781
1782 /* return the length of print_fmt */
1783 return pos;
1784}
1785
1786static int set_print_fmt(struct trace_probe *tp)
1787{
1788 int len;
1789 char *print_fmt;
1790
1791 /* First: called with 0 length to calculate the needed length */
1792 len = __set_print_fmt(tp, NULL, 0);
1793 print_fmt = kmalloc(len + 1, GFP_KERNEL);
1794 if (!print_fmt)
1795 return -ENOMEM;
1796
1797 /* Second: actually write the @print_fmt */
1798 __set_print_fmt(tp, print_fmt, len + 1);
1799 tp->call.print_fmt = print_fmt;
1800
1801 return 0;
1802}
1803
1804#ifdef CONFIG_PERF_EVENTS
1805
1806/* Kprobe profile handler */
1807static __kprobes void kprobe_perf_func(struct kprobe *kp,
1808 struct pt_regs *regs)
1809{
1810 struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1811 struct ftrace_event_call *call = &tp->call;
1812 struct kprobe_trace_entry_head *entry;
1813 struct hlist_head *head;
1814 int size, __size, dsize;
1815 int rctx;
1816
1817 dsize = __get_data_size(tp, regs);
1818 __size = sizeof(*entry) + tp->size + dsize;
1819 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1820 size -= sizeof(u32);
1821 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1822 "profile buffer not large enough"))
1823 return;
1824
1825 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1826 if (!entry)
1827 return;
1828
1829 entry->ip = (unsigned long)kp->addr;
1830 memset(&entry[1], 0, dsize);
1831 store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1832
1833 head = this_cpu_ptr(call->perf_events);
1834 perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
1835}
1836
1837/* Kretprobe profile handler */
1838static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
1839 struct pt_regs *regs)
1840{
1841 struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1842 struct ftrace_event_call *call = &tp->call;
1843 struct kretprobe_trace_entry_head *entry;
1844 struct hlist_head *head;
1845 int size, __size, dsize;
1846 int rctx;
1847
1848 dsize = __get_data_size(tp, regs);
1849 __size = sizeof(*entry) + tp->size + dsize;
1850 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1851 size -= sizeof(u32);
1852 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1853 "profile buffer not large enough"))
1854 return;
1855
1856 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1857 if (!entry)
1858 return;
1859
1860 entry->func = (unsigned long)tp->rp.kp.addr;
1861 entry->ret_ip = (unsigned long)ri->ret_addr;
1862 store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1863
1864 head = this_cpu_ptr(call->perf_events);
1865 perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
1866}
1867#endif /* CONFIG_PERF_EVENTS */
1868
1869static __kprobes
1870int kprobe_register(struct ftrace_event_call *event, enum trace_reg type)
1871{
1872 struct trace_probe *tp = (struct trace_probe *)event->data;
1873
1874 switch (type) {
1875 case TRACE_REG_REGISTER:
1876 return enable_trace_probe(tp, TP_FLAG_TRACE);
1877 case TRACE_REG_UNREGISTER:
1878 disable_trace_probe(tp, TP_FLAG_TRACE);
1879 return 0;
1880
1881#ifdef CONFIG_PERF_EVENTS
1882 case TRACE_REG_PERF_REGISTER:
1883 return enable_trace_probe(tp, TP_FLAG_PROFILE);
1884 case TRACE_REG_PERF_UNREGISTER:
1885 disable_trace_probe(tp, TP_FLAG_PROFILE);
1886 return 0;
1887#endif
1888 }
1889 return 0;
1890}
1891
1892static __kprobes
1893int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1894{
1895 struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1896
1897 if (tp->flags & TP_FLAG_TRACE)
1898 kprobe_trace_func(kp, regs);
1899#ifdef CONFIG_PERF_EVENTS
1900 if (tp->flags & TP_FLAG_PROFILE)
1901 kprobe_perf_func(kp, regs);
1902#endif
1903 return 0; /* We don't tweek kernel, so just return 0 */
1904}
1905
1906static __kprobes
1907int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1908{
1909 struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1910
1911 if (tp->flags & TP_FLAG_TRACE)
1912 kretprobe_trace_func(ri, regs);
1913#ifdef CONFIG_PERF_EVENTS
1914 if (tp->flags & TP_FLAG_PROFILE)
1915 kretprobe_perf_func(ri, regs);
1916#endif
1917 return 0; /* We don't tweek kernel, so just return 0 */
1918}
1919
1920static struct trace_event_functions kretprobe_funcs = {
1921 .trace = print_kretprobe_event
1922};
1923
1924static struct trace_event_functions kprobe_funcs = {
1925 .trace = print_kprobe_event
1926};
1927
1928static int register_probe_event(struct trace_probe *tp)
1929{
1930 struct ftrace_event_call *call = &tp->call;
1931 int ret;
1932
1933 /* Initialize ftrace_event_call */
1934 INIT_LIST_HEAD(&call->class->fields);
1935 if (trace_probe_is_return(tp)) {
1936 call->event.funcs = &kretprobe_funcs;
1937 call->class->define_fields = kretprobe_event_define_fields;
1938 } else {
1939 call->event.funcs = &kprobe_funcs;
1940 call->class->define_fields = kprobe_event_define_fields;
1941 }
1942 if (set_print_fmt(tp) < 0)
1943 return -ENOMEM;
1944 ret = register_ftrace_event(&call->event);
1945 if (!ret) {
1946 kfree(call->print_fmt);
1947 return -ENODEV;
1948 }
1949 call->flags = 0;
1950 call->class->reg = kprobe_register;
1951 call->data = tp;
1952 ret = trace_add_event_call(call);
1953 if (ret) {
1954 pr_info("Failed to register kprobe event: %s\n", call->name);
1955 kfree(call->print_fmt);
1956 unregister_ftrace_event(&call->event);
1957 }
1958 return ret;
1959}
1960
1961static void unregister_probe_event(struct trace_probe *tp)
1962{
1963 /* tp->event is unregistered in trace_remove_event_call() */
1964 trace_remove_event_call(&tp->call);
1965 kfree(tp->call.print_fmt);
1966}
1967
1968/* Make a debugfs interface for controlling probe points */
1969static __init int init_kprobe_trace(void)
1970{
1971 struct dentry *d_tracer;
1972 struct dentry *entry;
1973
1974 if (register_module_notifier(&trace_probe_module_nb))
1975 return -EINVAL;
1976
1977 d_tracer = tracing_init_dentry();
1978 if (!d_tracer)
1979 return 0;
1980
1981 entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1982 NULL, &kprobe_events_ops);
1983
1984 /* Event list interface */
1985 if (!entry)
1986 pr_warning("Could not create debugfs "
1987 "'kprobe_events' entry\n");
1988
1989 /* Profile interface */
1990 entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1991 NULL, &kprobe_profile_ops);
1992
1993 if (!entry)
1994 pr_warning("Could not create debugfs "
1995 "'kprobe_profile' entry\n");
1996 return 0;
1997}
1998fs_initcall(init_kprobe_trace);
1999
2000
2001#ifdef CONFIG_FTRACE_STARTUP_TEST
2002
2003/*
2004 * The "__used" keeps gcc from removing the function symbol
2005 * from the kallsyms table.
2006 */
2007static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
2008 int a4, int a5, int a6)
2009{
2010 return a1 + a2 + a3 + a4 + a5 + a6;
2011}
2012
2013static __init int kprobe_trace_self_tests_init(void)
2014{
2015 int ret, warn = 0;
2016 int (*target)(int, int, int, int, int, int);
2017 struct trace_probe *tp;
2018
2019 target = kprobe_trace_selftest_target;
2020
2021 pr_info("Testing kprobe tracing: ");
2022
2023 ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
2024 "$stack $stack0 +0($stack)");
2025 if (WARN_ON_ONCE(ret)) {
2026 pr_warning("error on probing function entry.\n");
2027 warn++;
2028 } else {
2029 /* Enable trace point */
2030 tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM);
2031 if (WARN_ON_ONCE(tp == NULL)) {
2032 pr_warning("error on getting new probe.\n");
2033 warn++;
2034 } else
2035 enable_trace_probe(tp, TP_FLAG_TRACE);
2036 }
2037
2038 ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
2039 "$retval");
2040 if (WARN_ON_ONCE(ret)) {
2041 pr_warning("error on probing function return.\n");
2042 warn++;
2043 } else {
2044 /* Enable trace point */
2045 tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM);
2046 if (WARN_ON_ONCE(tp == NULL)) {
2047 pr_warning("error on getting new probe.\n");
2048 warn++;
2049 } else
2050 enable_trace_probe(tp, TP_FLAG_TRACE);
2051 }
2052
2053 if (warn)
2054 goto end;
2055
2056 ret = target(1, 2, 3, 4, 5, 6);
2057
2058 ret = command_trace_probe("-:testprobe");
2059 if (WARN_ON_ONCE(ret)) {
2060 pr_warning("error on deleting a probe.\n");
2061 warn++;
2062 }
2063
2064 ret = command_trace_probe("-:testprobe2");
2065 if (WARN_ON_ONCE(ret)) {
2066 pr_warning("error on deleting a probe.\n");
2067 warn++;
2068 }
2069
2070end:
2071 release_all_trace_probes();
2072 if (warn)
2073 pr_cont("NG: Some tests are failed. Please check them.\n");
2074 else
2075 pr_cont("OK\n");
2076 return 0;
2077}
2078
2079late_initcall(kprobe_trace_self_tests_init);
2080
2081#endif