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CommitLineData
413d37d1 1/*
77b44d1b 2 * Kprobes-based tracing events
413d37d1
MH
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 */
72576341 19#define pr_fmt(fmt) "trace_kprobe: " fmt
413d37d1
MH
20
21#include <linux/module.h>
22#include <linux/uaccess.h>
b2d09103 23#include <linux/rculist.h>
413d37d1 24
8ab83f56 25#include "trace_probe.h"
1ff511e3 26
8ab83f56 27#define KPROBE_EVENT_SYSTEM "kprobes"
696ced4f 28#define KRETPROBE_MAXACTIVE_MAX 4096
e09c8614 29
413d37d1 30/**
77b44d1b 31 * Kprobe event core functions
413d37d1 32 */
c31ffb3f 33struct trace_kprobe {
413d37d1 34 struct list_head list;
4a846b44 35 struct kretprobe rp; /* Use rp.kp for kprobe use */
a7636d9e 36 unsigned long __percpu *nhit;
413d37d1 37 const char *symbol; /* symbol name */
c31ffb3f 38 struct trace_probe tp;
413d37d1
MH
39};
40
c31ffb3f
NK
41#define SIZEOF_TRACE_KPROBE(n) \
42 (offsetof(struct trace_kprobe, tp.args) + \
eca0d916 43 (sizeof(struct probe_arg) * (n)))
a82378d8 44
93ccae7a 45
3da0f180 46static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
413d37d1 47{
c31ffb3f 48 return tk->rp.handler != NULL;
413d37d1
MH
49}
50
3da0f180 51static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
413d37d1 52{
c31ffb3f 53 return tk->symbol ? tk->symbol : "unknown";
413d37d1
MH
54}
55
3da0f180 56static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
61424318 57{
c31ffb3f 58 return tk->rp.kp.offset;
61424318
MH
59}
60
3da0f180 61static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
61424318 62{
c31ffb3f 63 return !!(kprobe_gone(&tk->rp.kp));
61424318
MH
64}
65
3da0f180 66static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
c31ffb3f 67 struct module *mod)
61424318
MH
68{
69 int len = strlen(mod->name);
c31ffb3f 70 const char *name = trace_kprobe_symbol(tk);
61424318
MH
71 return strncmp(mod->name, name, len) == 0 && name[len] == ':';
72}
73
7782046e 74static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
61424318 75{
7782046e
MH
76 char *p;
77 bool ret;
78
79 if (!tk->symbol)
80 return false;
81 p = strchr(tk->symbol, ':');
82 if (!p)
83 return true;
84 *p = '\0';
85 mutex_lock(&module_mutex);
86 ret = !!find_module(tk->symbol);
87 mutex_unlock(&module_mutex);
88 *p = ':';
89
90 return ret;
61424318
MH
91}
92
f18f97ac
MN
93static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
94{
95 unsigned long nhit = 0;
96 int cpu;
97
98 for_each_possible_cpu(cpu)
99 nhit += *per_cpu_ptr(tk->nhit, cpu);
100
101 return nhit;
102}
103
c31ffb3f
NK
104static int register_kprobe_event(struct trace_kprobe *tk);
105static int unregister_kprobe_event(struct trace_kprobe *tk);
413d37d1
MH
106
107static DEFINE_MUTEX(probe_lock);
108static LIST_HEAD(probe_list);
109
50d78056
MH
110static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
111static int kretprobe_dispatcher(struct kretprobe_instance *ri,
112 struct pt_regs *regs);
113
1301a44e
NK
114/* Memory fetching by symbol */
115struct symbol_cache {
116 char *symbol;
117 long offset;
118 unsigned long addr;
119};
120
121unsigned long update_symbol_cache(struct symbol_cache *sc)
122{
123 sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
124
125 if (sc->addr)
126 sc->addr += sc->offset;
127
128 return sc->addr;
129}
130
131void free_symbol_cache(struct symbol_cache *sc)
132{
133 kfree(sc->symbol);
134 kfree(sc);
135}
136
137struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
138{
139 struct symbol_cache *sc;
140
141 if (!sym || strlen(sym) == 0)
142 return NULL;
143
144 sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
145 if (!sc)
146 return NULL;
147
148 sc->symbol = kstrdup(sym, GFP_KERNEL);
149 if (!sc->symbol) {
150 kfree(sc);
151 return NULL;
152 }
153 sc->offset = offset;
154 update_symbol_cache(sc);
155
156 return sc;
157}
158
3fd996a2
NK
159/*
160 * Kprobes-specific fetch functions
161 */
162#define DEFINE_FETCH_stack(type) \
3da0f180 163static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \
3fd996a2
NK
164 void *offset, void *dest) \
165{ \
166 *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
167 (unsigned int)((unsigned long)offset)); \
3da0f180
MH
168} \
169NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
170
3fd996a2
NK
171DEFINE_BASIC_FETCH_FUNCS(stack)
172/* No string on the stack entry */
173#define fetch_stack_string NULL
174#define fetch_stack_string_size NULL
175
5baaa59e 176#define DEFINE_FETCH_memory(type) \
3da0f180 177static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \
5baaa59e
NK
178 void *addr, void *dest) \
179{ \
180 type retval; \
181 if (probe_kernel_address(addr, retval)) \
182 *(type *)dest = 0; \
183 else \
184 *(type *)dest = retval; \
3da0f180
MH
185} \
186NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
187
5baaa59e
NK
188DEFINE_BASIC_FETCH_FUNCS(memory)
189/*
190 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
191 * length and relative data location.
192 */
3da0f180
MH
193static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
194 void *addr, void *dest)
5baaa59e 195{
5baaa59e
NK
196 int maxlen = get_rloc_len(*(u32 *)dest);
197 u8 *dst = get_rloc_data(dest);
1a6877b9 198 long ret;
5baaa59e
NK
199
200 if (!maxlen)
201 return;
202
203 /*
204 * Try to get string again, since the string can be changed while
205 * probing.
206 */
1a6877b9 207 ret = strncpy_from_unsafe(dst, addr, maxlen);
5baaa59e
NK
208
209 if (ret < 0) { /* Failed to fetch string */
1a6877b9 210 dst[0] = '\0';
5baaa59e
NK
211 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
212 } else {
1a6877b9 213 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
5baaa59e
NK
214 }
215}
3da0f180 216NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
5baaa59e
NK
217
218/* Return the length of string -- including null terminal byte */
3da0f180
MH
219static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
220 void *addr, void *dest)
5baaa59e
NK
221{
222 mm_segment_t old_fs;
223 int ret, len = 0;
224 u8 c;
225
226 old_fs = get_fs();
227 set_fs(KERNEL_DS);
228 pagefault_disable();
229
230 do {
231 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
232 len++;
233 } while (c && ret == 0 && len < MAX_STRING_SIZE);
234
235 pagefault_enable();
236 set_fs(old_fs);
237
238 if (ret < 0) /* Failed to check the length */
239 *(u32 *)dest = 0;
240 else
241 *(u32 *)dest = len;
242}
3da0f180 243NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
5baaa59e 244
1301a44e 245#define DEFINE_FETCH_symbol(type) \
3da0f180 246void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\
1301a44e
NK
247{ \
248 struct symbol_cache *sc = data; \
249 if (sc->addr) \
250 fetch_memory_##type(regs, (void *)sc->addr, dest); \
251 else \
252 *(type *)dest = 0; \
3da0f180
MH
253} \
254NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
255
1301a44e
NK
256DEFINE_BASIC_FETCH_FUNCS(symbol)
257DEFINE_FETCH_symbol(string)
258DEFINE_FETCH_symbol(string_size)
259
b7e0bf34
NK
260/* kprobes don't support file_offset fetch methods */
261#define fetch_file_offset_u8 NULL
262#define fetch_file_offset_u16 NULL
263#define fetch_file_offset_u32 NULL
264#define fetch_file_offset_u64 NULL
265#define fetch_file_offset_string NULL
266#define fetch_file_offset_string_size NULL
267
34fee3a1 268/* Fetch type information table */
d9a16d3a 269static const struct fetch_type kprobes_fetch_type_table[] = {
34fee3a1
NK
270 /* Special types */
271 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
272 sizeof(u32), 1, "__data_loc char[]"),
273 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
274 string_size, sizeof(u32), 0, "u32"),
275 /* Basic types */
276 ASSIGN_FETCH_TYPE(u8, u8, 0),
277 ASSIGN_FETCH_TYPE(u16, u16, 0),
278 ASSIGN_FETCH_TYPE(u32, u32, 0),
279 ASSIGN_FETCH_TYPE(u64, u64, 0),
280 ASSIGN_FETCH_TYPE(s8, u8, 1),
281 ASSIGN_FETCH_TYPE(s16, u16, 1),
282 ASSIGN_FETCH_TYPE(s32, u32, 1),
283 ASSIGN_FETCH_TYPE(s64, u64, 1),
17ce3dc7
MH
284 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
285 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
286 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
287 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
34fee3a1
NK
288
289 ASSIGN_FETCH_TYPE_END
290};
291
4a846b44
MH
292/*
293 * Allocate new trace_probe and initialize it (including kprobes).
294 */
c31ffb3f 295static struct trace_kprobe *alloc_trace_kprobe(const char *group,
f52487e9 296 const char *event,
4a846b44
MH
297 void *addr,
298 const char *symbol,
299 unsigned long offs,
696ced4f 300 int maxactive,
3a6b7666 301 int nargs, bool is_return)
413d37d1 302{
c31ffb3f 303 struct trace_kprobe *tk;
6f3cf440 304 int ret = -ENOMEM;
413d37d1 305
c31ffb3f
NK
306 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
307 if (!tk)
6f3cf440 308 return ERR_PTR(ret);
413d37d1 309
a7636d9e
MKL
310 tk->nhit = alloc_percpu(unsigned long);
311 if (!tk->nhit)
312 goto error;
313
413d37d1 314 if (symbol) {
c31ffb3f
NK
315 tk->symbol = kstrdup(symbol, GFP_KERNEL);
316 if (!tk->symbol)
413d37d1 317 goto error;
c31ffb3f
NK
318 tk->rp.kp.symbol_name = tk->symbol;
319 tk->rp.kp.offset = offs;
4a846b44 320 } else
c31ffb3f 321 tk->rp.kp.addr = addr;
4a846b44
MH
322
323 if (is_return)
c31ffb3f 324 tk->rp.handler = kretprobe_dispatcher;
4a846b44 325 else
c31ffb3f 326 tk->rp.kp.pre_handler = kprobe_dispatcher;
4a846b44 327
696ced4f
AC
328 tk->rp.maxactive = maxactive;
329
da34634f 330 if (!event || !is_good_name(event)) {
6f3cf440 331 ret = -EINVAL;
4263565d 332 goto error;
6f3cf440
MH
333 }
334
c31ffb3f
NK
335 tk->tp.call.class = &tk->tp.class;
336 tk->tp.call.name = kstrdup(event, GFP_KERNEL);
337 if (!tk->tp.call.name)
4263565d 338 goto error;
413d37d1 339
da34634f 340 if (!group || !is_good_name(group)) {
6f3cf440 341 ret = -EINVAL;
f52487e9 342 goto error;
6f3cf440
MH
343 }
344
c31ffb3f
NK
345 tk->tp.class.system = kstrdup(group, GFP_KERNEL);
346 if (!tk->tp.class.system)
f52487e9
MH
347 goto error;
348
c31ffb3f
NK
349 INIT_LIST_HEAD(&tk->list);
350 INIT_LIST_HEAD(&tk->tp.files);
351 return tk;
413d37d1 352error:
c31ffb3f
NK
353 kfree(tk->tp.call.name);
354 kfree(tk->symbol);
a7636d9e 355 free_percpu(tk->nhit);
c31ffb3f 356 kfree(tk);
6f3cf440 357 return ERR_PTR(ret);
413d37d1
MH
358}
359
c31ffb3f 360static void free_trace_kprobe(struct trace_kprobe *tk)
413d37d1
MH
361{
362 int i;
363
c31ffb3f
NK
364 for (i = 0; i < tk->tp.nr_args; i++)
365 traceprobe_free_probe_arg(&tk->tp.args[i]);
413d37d1 366
c31ffb3f
NK
367 kfree(tk->tp.call.class->system);
368 kfree(tk->tp.call.name);
369 kfree(tk->symbol);
a7636d9e 370 free_percpu(tk->nhit);
c31ffb3f 371 kfree(tk);
413d37d1
MH
372}
373
c31ffb3f
NK
374static struct trace_kprobe *find_trace_kprobe(const char *event,
375 const char *group)
413d37d1 376{
c31ffb3f 377 struct trace_kprobe *tk;
413d37d1 378
c31ffb3f 379 list_for_each_entry(tk, &probe_list, list)
687fcc4a 380 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
c31ffb3f
NK
381 strcmp(tk->tp.call.class->system, group) == 0)
382 return tk;
413d37d1
MH
383 return NULL;
384}
385
41a7dd42
MH
386/*
387 * Enable trace_probe
388 * if the file is NULL, enable "perf" handler, or enable "trace" handler.
389 */
390static int
7f1d2f82 391enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
1538f888 392{
9da1cac2 393 struct event_file_link *link = NULL;
1538f888
MH
394 int ret = 0;
395
41a7dd42 396 if (file) {
b04d52e3
ON
397 link = kmalloc(sizeof(*link), GFP_KERNEL);
398 if (!link) {
41a7dd42 399 ret = -ENOMEM;
3fe3d619 400 goto out;
41a7dd42 401 }
41a7dd42 402
b04d52e3 403 link->file = file;
c31ffb3f 404 list_add_tail_rcu(&link->list, &tk->tp.files);
41a7dd42 405
c31ffb3f 406 tk->tp.flags |= TP_FLAG_TRACE;
41a7dd42 407 } else
c31ffb3f 408 tk->tp.flags |= TP_FLAG_PROFILE;
41a7dd42 409
c31ffb3f
NK
410 if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
411 if (trace_kprobe_is_return(tk))
412 ret = enable_kretprobe(&tk->rp);
1538f888 413 else
c31ffb3f 414 ret = enable_kprobe(&tk->rp.kp);
1538f888 415 }
1f9ea57f
AS
416
417 if (ret) {
418 if (file) {
9da1cac2
SRV
419 /* Notice the if is true on not WARN() */
420 if (!WARN_ON_ONCE(!link))
421 list_del_rcu(&link->list);
1f9ea57f
AS
422 kfree(link);
423 tk->tp.flags &= ~TP_FLAG_TRACE;
424 } else {
425 tk->tp.flags &= ~TP_FLAG_PROFILE;
426 }
427 }
3fe3d619 428 out:
1538f888
MH
429 return ret;
430}
431
41a7dd42
MH
432/*
433 * Disable trace_probe
434 * if the file is NULL, disable "perf" handler, or disable "trace" handler.
435 */
436static int
7f1d2f82 437disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
1538f888 438{
a232e270
MH
439 struct event_file_link *link = NULL;
440 int wait = 0;
41a7dd42
MH
441 int ret = 0;
442
41a7dd42 443 if (file) {
c31ffb3f 444 link = find_event_file_link(&tk->tp, file);
b04d52e3 445 if (!link) {
41a7dd42 446 ret = -EINVAL;
3fe3d619 447 goto out;
41a7dd42
MH
448 }
449
b04d52e3 450 list_del_rcu(&link->list);
a232e270 451 wait = 1;
c31ffb3f 452 if (!list_empty(&tk->tp.files))
b04d52e3 453 goto out;
41a7dd42 454
c31ffb3f 455 tk->tp.flags &= ~TP_FLAG_TRACE;
41a7dd42 456 } else
c31ffb3f 457 tk->tp.flags &= ~TP_FLAG_PROFILE;
41a7dd42 458
c31ffb3f
NK
459 if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
460 if (trace_kprobe_is_return(tk))
461 disable_kretprobe(&tk->rp);
1538f888 462 else
c31ffb3f 463 disable_kprobe(&tk->rp.kp);
a232e270 464 wait = 1;
1538f888 465 }
3fe3d619 466 out:
a232e270
MH
467 if (wait) {
468 /*
469 * Synchronize with kprobe_trace_func/kretprobe_trace_func
470 * to ensure disabled (all running handlers are finished).
471 * This is not only for kfree(), but also the caller,
472 * trace_remove_event_call() supposes it for releasing
473 * event_call related objects, which will be accessed in
474 * the kprobe_trace_func/kretprobe_trace_func.
475 */
476 synchronize_sched();
477 kfree(link); /* Ignored if link == NULL */
478 }
479
41a7dd42 480 return ret;
1538f888
MH
481}
482
61424318 483/* Internal register function - just handle k*probes and flags */
c31ffb3f 484static int __register_trace_kprobe(struct trace_kprobe *tk)
413d37d1 485{
7f6878a3 486 int i, ret;
61424318 487
c31ffb3f 488 if (trace_probe_is_registered(&tk->tp))
61424318
MH
489 return -EINVAL;
490
c31ffb3f
NK
491 for (i = 0; i < tk->tp.nr_args; i++)
492 traceprobe_update_arg(&tk->tp.args[i]);
7f6878a3 493
61424318 494 /* Set/clear disabled flag according to tp->flag */
c31ffb3f
NK
495 if (trace_probe_is_enabled(&tk->tp))
496 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
61424318 497 else
c31ffb3f 498 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
61424318 499
c31ffb3f
NK
500 if (trace_kprobe_is_return(tk))
501 ret = register_kretprobe(&tk->rp);
413d37d1 502 else
c31ffb3f 503 ret = register_kprobe(&tk->rp.kp);
61424318 504
7782046e 505 if (ret == 0) {
c31ffb3f 506 tk->tp.flags |= TP_FLAG_REGISTERED;
7782046e
MH
507 } else if (ret == -EILSEQ) {
508 pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
509 tk->rp.kp.addr);
510 ret = -EINVAL;
61424318 511 }
61424318
MH
512 return ret;
513}
514
515/* Internal unregister function - just handle k*probes and flags */
c31ffb3f 516static void __unregister_trace_kprobe(struct trace_kprobe *tk)
61424318 517{
c31ffb3f
NK
518 if (trace_probe_is_registered(&tk->tp)) {
519 if (trace_kprobe_is_return(tk))
520 unregister_kretprobe(&tk->rp);
61424318 521 else
c31ffb3f
NK
522 unregister_kprobe(&tk->rp.kp);
523 tk->tp.flags &= ~TP_FLAG_REGISTERED;
61424318 524 /* Cleanup kprobe for reuse */
c31ffb3f
NK
525 if (tk->rp.kp.symbol_name)
526 tk->rp.kp.addr = NULL;
61424318
MH
527 }
528}
529
530/* Unregister a trace_probe and probe_event: call with locking probe_lock */
c31ffb3f 531static int unregister_trace_kprobe(struct trace_kprobe *tk)
61424318 532{
02ca1521 533 /* Enabled event can not be unregistered */
c31ffb3f 534 if (trace_probe_is_enabled(&tk->tp))
02ca1521
MH
535 return -EBUSY;
536
40c32592 537 /* Will fail if probe is being used by ftrace or perf */
c31ffb3f 538 if (unregister_kprobe_event(tk))
40c32592
SRRH
539 return -EBUSY;
540
c31ffb3f
NK
541 __unregister_trace_kprobe(tk);
542 list_del(&tk->list);
02ca1521
MH
543
544 return 0;
413d37d1
MH
545}
546
547/* Register a trace_probe and probe_event */
c31ffb3f 548static int register_trace_kprobe(struct trace_kprobe *tk)
413d37d1 549{
c31ffb3f 550 struct trace_kprobe *old_tk;
413d37d1
MH
551 int ret;
552
553 mutex_lock(&probe_lock);
554
61424318 555 /* Delete old (same name) event if exist */
687fcc4a 556 old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
de7b2973 557 tk->tp.call.class->system);
c31ffb3f
NK
558 if (old_tk) {
559 ret = unregister_trace_kprobe(old_tk);
02ca1521
MH
560 if (ret < 0)
561 goto end;
c31ffb3f 562 free_trace_kprobe(old_tk);
2d5e067e 563 }
61424318
MH
564
565 /* Register new event */
c31ffb3f 566 ret = register_kprobe_event(tk);
2d5e067e 567 if (ret) {
a395d6a7 568 pr_warn("Failed to register probe event(%d)\n", ret);
2d5e067e
MH
569 goto end;
570 }
571
61424318 572 /* Register k*probe */
c31ffb3f 573 ret = __register_trace_kprobe(tk);
7782046e
MH
574 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
575 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
576 ret = 0;
577 }
578
61424318 579 if (ret < 0)
c31ffb3f 580 unregister_kprobe_event(tk);
61424318 581 else
c31ffb3f 582 list_add_tail(&tk->list, &probe_list);
61424318 583
413d37d1
MH
584end:
585 mutex_unlock(&probe_lock);
586 return ret;
587}
588
61424318 589/* Module notifier call back, checking event on the module */
c31ffb3f 590static int trace_kprobe_module_callback(struct notifier_block *nb,
61424318
MH
591 unsigned long val, void *data)
592{
593 struct module *mod = data;
c31ffb3f 594 struct trace_kprobe *tk;
61424318
MH
595 int ret;
596
597 if (val != MODULE_STATE_COMING)
598 return NOTIFY_DONE;
599
600 /* Update probes on coming module */
601 mutex_lock(&probe_lock);
c31ffb3f
NK
602 list_for_each_entry(tk, &probe_list, list) {
603 if (trace_kprobe_within_module(tk, mod)) {
02ca1521 604 /* Don't need to check busy - this should have gone. */
c31ffb3f
NK
605 __unregister_trace_kprobe(tk);
606 ret = __register_trace_kprobe(tk);
61424318 607 if (ret)
a395d6a7
JP
608 pr_warn("Failed to re-register probe %s on %s: %d\n",
609 trace_event_name(&tk->tp.call),
610 mod->name, ret);
61424318
MH
611 }
612 }
613 mutex_unlock(&probe_lock);
614
615 return NOTIFY_DONE;
616}
617
c31ffb3f
NK
618static struct notifier_block trace_kprobe_module_nb = {
619 .notifier_call = trace_kprobe_module_callback,
61424318
MH
620 .priority = 1 /* Invoked after kprobe module callback */
621};
622
fca18a47
NR
623/* Convert certain expected symbols into '_' when generating event names */
624static inline void sanitize_event_name(char *name)
625{
626 while (*name++ != '\0')
627 if (*name == ':' || *name == '.')
628 *name = '_';
629}
630
c31ffb3f 631static int create_trace_kprobe(int argc, char **argv)
413d37d1
MH
632{
633 /*
634 * Argument syntax:
696ced4f
AC
635 * - Add kprobe:
636 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
637 * - Add kretprobe:
638 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
413d37d1 639 * Fetch args:
2e06ff63
MH
640 * $retval : fetch return value
641 * $stack : fetch stack address
642 * $stackN : fetch Nth of stack (N:0-)
35abb67d 643 * $comm : fetch current task comm
413d37d1
MH
644 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
645 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
646 * %REG : fetch register REG
93ccae7a 647 * Dereferencing memory fetch:
413d37d1 648 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
eca0d916
MH
649 * Alias name of args:
650 * NAME=FETCHARG : set NAME as alias of FETCHARG.
93ccae7a
MH
651 * Type of args:
652 * FETCHARG:TYPE : use TYPE instead of unsigned long.
413d37d1 653 */
c31ffb3f 654 struct trace_kprobe *tk;
413d37d1 655 int i, ret = 0;
3a6b7666 656 bool is_return = false, is_delete = false;
93ccae7a 657 char *symbol = NULL, *event = NULL, *group = NULL;
696ced4f 658 int maxactive = 0;
da34634f 659 char *arg;
a35ee0b0 660 long offset = 0;
413d37d1 661 void *addr = NULL;
4a846b44 662 char buf[MAX_EVENT_NAME_LEN];
413d37d1 663
a7c312be 664 /* argc must be >= 1 */
413d37d1 665 if (argv[0][0] == 'p')
3a6b7666 666 is_return = false;
413d37d1 667 else if (argv[0][0] == 'r')
3a6b7666 668 is_return = true;
a7c312be 669 else if (argv[0][0] == '-')
3a6b7666 670 is_delete = true;
e63cc239 671 else {
a7c312be
MH
672 pr_info("Probe definition must be started with 'p', 'r' or"
673 " '-'.\n");
413d37d1 674 return -EINVAL;
e63cc239 675 }
413d37d1 676
696ced4f
AC
677 event = strchr(&argv[0][1], ':');
678 if (event) {
679 event[0] = '\0';
680 event++;
681 }
682 if (is_return && isdigit(argv[0][1])) {
683 ret = kstrtouint(&argv[0][1], 0, &maxactive);
684 if (ret) {
685 pr_info("Failed to parse maxactive.\n");
686 return ret;
687 }
688 /* kretprobes instances are iterated over via a list. The
689 * maximum should stay reasonable.
690 */
691 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
692 pr_info("Maxactive is too big (%d > %d).\n",
693 maxactive, KRETPROBE_MAXACTIVE_MAX);
694 return -E2BIG;
695 }
696 }
697
698 if (event) {
f52487e9
MH
699 if (strchr(event, '/')) {
700 group = event;
701 event = strchr(group, '/') + 1;
702 event[-1] = '\0';
703 if (strlen(group) == 0) {
a5efd925 704 pr_info("Group name is not specified\n");
f52487e9
MH
705 return -EINVAL;
706 }
707 }
413d37d1 708 if (strlen(event) == 0) {
a5efd925 709 pr_info("Event name is not specified\n");
413d37d1
MH
710 return -EINVAL;
711 }
712 }
a7c312be
MH
713 if (!group)
714 group = KPROBE_EVENT_SYSTEM;
413d37d1 715
a7c312be
MH
716 if (is_delete) {
717 if (!event) {
718 pr_info("Delete command needs an event name.\n");
719 return -EINVAL;
720 }
9da79ab8 721 mutex_lock(&probe_lock);
c31ffb3f
NK
722 tk = find_trace_kprobe(event, group);
723 if (!tk) {
9da79ab8 724 mutex_unlock(&probe_lock);
a7c312be
MH
725 pr_info("Event %s/%s doesn't exist.\n", group, event);
726 return -ENOENT;
727 }
728 /* delete an event */
c31ffb3f 729 ret = unregister_trace_kprobe(tk);
02ca1521 730 if (ret == 0)
c31ffb3f 731 free_trace_kprobe(tk);
9da79ab8 732 mutex_unlock(&probe_lock);
02ca1521 733 return ret;
a7c312be
MH
734 }
735
736 if (argc < 2) {
737 pr_info("Probe point is not specified.\n");
738 return -EINVAL;
739 }
9e52b325
SD
740
741 /* try to parse an address. if that fails, try to read the
742 * input as a symbol. */
743 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
413d37d1
MH
744 /* a symbol specified */
745 symbol = argv[1];
746 /* TODO: support .init module functions */
8ab83f56 747 ret = traceprobe_split_symbol_offset(symbol, &offset);
a35ee0b0 748 if (ret || offset < 0 || offset > UINT_MAX) {
9e52b325 749 pr_info("Failed to parse either an address or a symbol.\n");
413d37d1 750 return ret;
e63cc239 751 }
d0e02579 752 if (offset && is_return &&
659b957f 753 !kprobe_on_func_entry(NULL, symbol, offset)) {
d0e02579 754 pr_info("Given offset is not valid for return probe.\n");
413d37d1 755 return -EINVAL;
e63cc239 756 }
413d37d1 757 }
a82378d8 758 argc -= 2; argv += 2;
413d37d1
MH
759
760 /* setup a probe */
4263565d
MH
761 if (!event) {
762 /* Make a new event name */
4263565d 763 if (symbol)
6f3cf440 764 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
4263565d
MH
765 is_return ? 'r' : 'p', symbol, offset);
766 else
6f3cf440 767 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
4263565d 768 is_return ? 'r' : 'p', addr);
fca18a47 769 sanitize_event_name(buf);
4a846b44
MH
770 event = buf;
771 }
696ced4f
AC
772 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
773 argc, is_return);
c31ffb3f 774 if (IS_ERR(tk)) {
e63cc239 775 pr_info("Failed to allocate trace_probe.(%d)\n",
c31ffb3f
NK
776 (int)PTR_ERR(tk));
777 return PTR_ERR(tk);
e63cc239 778 }
413d37d1 779
413d37d1 780 /* parse arguments */
a82378d8
MH
781 ret = 0;
782 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
c31ffb3f
NK
783 struct probe_arg *parg = &tk->tp.args[i];
784
61a52736 785 /* Increment count for freeing args in error case */
c31ffb3f 786 tk->tp.nr_args++;
61a52736 787
eca0d916
MH
788 /* Parse argument name */
789 arg = strchr(argv[i], '=');
aba91595 790 if (arg) {
eca0d916 791 *arg++ = '\0';
c31ffb3f 792 parg->name = kstrdup(argv[i], GFP_KERNEL);
aba91595 793 } else {
eca0d916 794 arg = argv[i];
aba91595
MH
795 /* If argument name is omitted, set "argN" */
796 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
c31ffb3f 797 parg->name = kstrdup(buf, GFP_KERNEL);
aba91595 798 }
a703d946 799
c31ffb3f 800 if (!parg->name) {
aba91595 801 pr_info("Failed to allocate argument[%d] name.\n", i);
ba8665d7 802 ret = -ENOMEM;
413d37d1
MH
803 goto error;
804 }
da34634f 805
c31ffb3f 806 if (!is_good_name(parg->name)) {
da34634f 807 pr_info("Invalid argument[%d] name: %s\n",
c31ffb3f 808 i, parg->name);
da34634f
MH
809 ret = -EINVAL;
810 goto error;
811 }
93ccae7a 812
c31ffb3f
NK
813 if (traceprobe_conflict_field_name(parg->name,
814 tk->tp.args, i)) {
aba91595 815 pr_info("Argument[%d] name '%s' conflicts with "
93ccae7a
MH
816 "another field.\n", i, argv[i]);
817 ret = -EINVAL;
818 goto error;
819 }
ba8665d7
MH
820
821 /* Parse fetch argument */
c31ffb3f 822 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
d9a16d3a
SR
823 is_return, true,
824 kprobes_fetch_type_table);
e63cc239 825 if (ret) {
aba91595 826 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
413d37d1 827 goto error;
e63cc239 828 }
413d37d1 829 }
413d37d1 830
c31ffb3f 831 ret = register_trace_kprobe(tk);
413d37d1
MH
832 if (ret)
833 goto error;
834 return 0;
835
836error:
c31ffb3f 837 free_trace_kprobe(tk);
413d37d1
MH
838 return ret;
839}
840
c31ffb3f 841static int release_all_trace_kprobes(void)
413d37d1 842{
c31ffb3f 843 struct trace_kprobe *tk;
02ca1521 844 int ret = 0;
413d37d1
MH
845
846 mutex_lock(&probe_lock);
02ca1521 847 /* Ensure no probe is in use. */
c31ffb3f
NK
848 list_for_each_entry(tk, &probe_list, list)
849 if (trace_probe_is_enabled(&tk->tp)) {
02ca1521
MH
850 ret = -EBUSY;
851 goto end;
852 }
413d37d1
MH
853 /* TODO: Use batch unregistration */
854 while (!list_empty(&probe_list)) {
c31ffb3f
NK
855 tk = list_entry(probe_list.next, struct trace_kprobe, list);
856 ret = unregister_trace_kprobe(tk);
40c32592
SRRH
857 if (ret)
858 goto end;
c31ffb3f 859 free_trace_kprobe(tk);
413d37d1 860 }
02ca1521
MH
861
862end:
413d37d1 863 mutex_unlock(&probe_lock);
02ca1521
MH
864
865 return ret;
413d37d1
MH
866}
867
413d37d1
MH
868/* Probes listing interfaces */
869static void *probes_seq_start(struct seq_file *m, loff_t *pos)
870{
871 mutex_lock(&probe_lock);
872 return seq_list_start(&probe_list, *pos);
873}
874
875static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
876{
877 return seq_list_next(v, &probe_list, pos);
878}
879
880static void probes_seq_stop(struct seq_file *m, void *v)
881{
882 mutex_unlock(&probe_lock);
883}
884
885static int probes_seq_show(struct seq_file *m, void *v)
886{
c31ffb3f 887 struct trace_kprobe *tk = v;
93ccae7a 888 int i;
413d37d1 889
fa6f0cc7 890 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
de7b2973 891 seq_printf(m, ":%s/%s", tk->tp.call.class->system,
687fcc4a 892 trace_event_name(&tk->tp.call));
413d37d1 893
c31ffb3f
NK
894 if (!tk->symbol)
895 seq_printf(m, " 0x%p", tk->rp.kp.addr);
896 else if (tk->rp.kp.offset)
897 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
898 tk->rp.kp.offset);
413d37d1 899 else
c31ffb3f 900 seq_printf(m, " %s", trace_kprobe_symbol(tk));
413d37d1 901
c31ffb3f
NK
902 for (i = 0; i < tk->tp.nr_args; i++)
903 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
fa6f0cc7 904 seq_putc(m, '\n');
93ccae7a 905
413d37d1
MH
906 return 0;
907}
908
909static const struct seq_operations probes_seq_op = {
910 .start = probes_seq_start,
911 .next = probes_seq_next,
912 .stop = probes_seq_stop,
913 .show = probes_seq_show
914};
915
916static int probes_open(struct inode *inode, struct file *file)
917{
02ca1521
MH
918 int ret;
919
920 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
c31ffb3f 921 ret = release_all_trace_kprobes();
02ca1521
MH
922 if (ret < 0)
923 return ret;
924 }
413d37d1
MH
925
926 return seq_open(file, &probes_seq_op);
927}
928
413d37d1
MH
929static ssize_t probes_write(struct file *file, const char __user *buffer,
930 size_t count, loff_t *ppos)
931{
7e465baa
TZ
932 return trace_parse_run_command(file, buffer, count, ppos,
933 create_trace_kprobe);
413d37d1
MH
934}
935
936static const struct file_operations kprobe_events_ops = {
937 .owner = THIS_MODULE,
938 .open = probes_open,
939 .read = seq_read,
940 .llseek = seq_lseek,
941 .release = seq_release,
942 .write = probes_write,
943};
944
cd7e7bd5
MH
945/* Probes profiling interfaces */
946static int probes_profile_seq_show(struct seq_file *m, void *v)
947{
c31ffb3f 948 struct trace_kprobe *tk = v;
cd7e7bd5 949
de7b2973 950 seq_printf(m, " %-44s %15lu %15lu\n",
f18f97ac
MN
951 trace_event_name(&tk->tp.call),
952 trace_kprobe_nhit(tk),
c31ffb3f 953 tk->rp.kp.nmissed);
cd7e7bd5
MH
954
955 return 0;
956}
957
958static const struct seq_operations profile_seq_op = {
959 .start = probes_seq_start,
960 .next = probes_seq_next,
961 .stop = probes_seq_stop,
962 .show = probes_profile_seq_show
963};
964
965static int profile_open(struct inode *inode, struct file *file)
966{
967 return seq_open(file, &profile_seq_op);
968}
969
970static const struct file_operations kprobe_profile_ops = {
971 .owner = THIS_MODULE,
972 .open = profile_open,
973 .read = seq_read,
974 .llseek = seq_lseek,
975 .release = seq_release,
976};
977
413d37d1 978/* Kprobe handler */
3da0f180 979static nokprobe_inline void
c31ffb3f 980__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
7f1d2f82 981 struct trace_event_file *trace_file)
413d37d1 982{
93ccae7a 983 struct kprobe_trace_entry_head *entry;
413d37d1 984 struct ring_buffer_event *event;
8f8ffe24 985 struct ring_buffer *buffer;
e09c8614 986 int size, dsize, pc;
413d37d1 987 unsigned long irq_flags;
2425bcb9 988 struct trace_event_call *call = &tk->tp.call;
413d37d1 989
7f1d2f82 990 WARN_ON(call != trace_file->event_call);
41a7dd42 991
09a5059a 992 if (trace_trigger_soft_disabled(trace_file))
13a1e4ae 993 return;
b8820084 994
413d37d1
MH
995 local_save_flags(irq_flags);
996 pc = preempt_count();
997
c31ffb3f
NK
998 dsize = __get_data_size(&tk->tp, regs);
999 size = sizeof(*entry) + tk->tp.size + dsize;
413d37d1 1000
7f1d2f82 1001 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
41a7dd42
MH
1002 call->event.type,
1003 size, irq_flags, pc);
413d37d1 1004 if (!event)
1e12a4a7 1005 return;
413d37d1
MH
1006
1007 entry = ring_buffer_event_data(event);
c31ffb3f
NK
1008 entry->ip = (unsigned long)tk->rp.kp.addr;
1009 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
413d37d1 1010
7f1d2f82 1011 event_trigger_unlock_commit_regs(trace_file, buffer, event,
13a1e4ae 1012 entry, irq_flags, pc, regs);
413d37d1
MH
1013}
1014
3da0f180 1015static void
c31ffb3f 1016kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
41a7dd42 1017{
b04d52e3 1018 struct event_file_link *link;
41a7dd42 1019
c31ffb3f
NK
1020 list_for_each_entry_rcu(link, &tk->tp.files, list)
1021 __kprobe_trace_func(tk, regs, link->file);
41a7dd42 1022}
3da0f180 1023NOKPROBE_SYMBOL(kprobe_trace_func);
41a7dd42 1024
413d37d1 1025/* Kretprobe handler */
3da0f180 1026static nokprobe_inline void
c31ffb3f 1027__kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
41a7dd42 1028 struct pt_regs *regs,
7f1d2f82 1029 struct trace_event_file *trace_file)
413d37d1 1030{
93ccae7a 1031 struct kretprobe_trace_entry_head *entry;
413d37d1 1032 struct ring_buffer_event *event;
8f8ffe24 1033 struct ring_buffer *buffer;
e09c8614 1034 int size, pc, dsize;
413d37d1 1035 unsigned long irq_flags;
2425bcb9 1036 struct trace_event_call *call = &tk->tp.call;
413d37d1 1037
7f1d2f82 1038 WARN_ON(call != trace_file->event_call);
41a7dd42 1039
09a5059a 1040 if (trace_trigger_soft_disabled(trace_file))
13a1e4ae 1041 return;
b8820084 1042
413d37d1
MH
1043 local_save_flags(irq_flags);
1044 pc = preempt_count();
1045
c31ffb3f
NK
1046 dsize = __get_data_size(&tk->tp, regs);
1047 size = sizeof(*entry) + tk->tp.size + dsize;
413d37d1 1048
7f1d2f82 1049 event = trace_event_buffer_lock_reserve(&buffer, trace_file,
41a7dd42
MH
1050 call->event.type,
1051 size, irq_flags, pc);
413d37d1 1052 if (!event)
1e12a4a7 1053 return;
413d37d1
MH
1054
1055 entry = ring_buffer_event_data(event);
c31ffb3f 1056 entry->func = (unsigned long)tk->rp.kp.addr;
413d37d1 1057 entry->ret_ip = (unsigned long)ri->ret_addr;
c31ffb3f 1058 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
413d37d1 1059
7f1d2f82 1060 event_trigger_unlock_commit_regs(trace_file, buffer, event,
13a1e4ae 1061 entry, irq_flags, pc, regs);
413d37d1
MH
1062}
1063
3da0f180 1064static void
c31ffb3f 1065kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
41a7dd42
MH
1066 struct pt_regs *regs)
1067{
b04d52e3 1068 struct event_file_link *link;
41a7dd42 1069
c31ffb3f
NK
1070 list_for_each_entry_rcu(link, &tk->tp.files, list)
1071 __kretprobe_trace_func(tk, ri, regs, link->file);
41a7dd42 1072}
3da0f180 1073NOKPROBE_SYMBOL(kretprobe_trace_func);
41a7dd42 1074
413d37d1 1075/* Event entry printers */
b62fdd97 1076static enum print_line_t
a9a57763
SR
1077print_kprobe_event(struct trace_iterator *iter, int flags,
1078 struct trace_event *event)
413d37d1 1079{
93ccae7a 1080 struct kprobe_trace_entry_head *field;
413d37d1 1081 struct trace_seq *s = &iter->seq;
eca0d916 1082 struct trace_probe *tp;
93ccae7a 1083 u8 *data;
413d37d1
MH
1084 int i;
1085
93ccae7a 1086 field = (struct kprobe_trace_entry_head *)iter->ent;
80decc70 1087 tp = container_of(event, struct trace_probe, call.event);
413d37d1 1088
687fcc4a 1089 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
6e9f23d1 1090
413d37d1 1091 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
85224da0 1092 goto out;
413d37d1 1093
85224da0 1094 trace_seq_putc(s, ')');
413d37d1 1095
93ccae7a
MH
1096 data = (u8 *)&field[1];
1097 for (i = 0; i < tp->nr_args; i++)
1098 if (!tp->args[i].type->print(s, tp->args[i].name,
e09c8614 1099 data + tp->args[i].offset, field))
85224da0 1100 goto out;
413d37d1 1101
85224da0
SRRH
1102 trace_seq_putc(s, '\n');
1103 out:
1104 return trace_handle_return(s);
413d37d1
MH
1105}
1106
b62fdd97 1107static enum print_line_t
a9a57763
SR
1108print_kretprobe_event(struct trace_iterator *iter, int flags,
1109 struct trace_event *event)
413d37d1 1110{
93ccae7a 1111 struct kretprobe_trace_entry_head *field;
413d37d1 1112 struct trace_seq *s = &iter->seq;
eca0d916 1113 struct trace_probe *tp;
93ccae7a 1114 u8 *data;
413d37d1
MH
1115 int i;
1116
93ccae7a 1117 field = (struct kretprobe_trace_entry_head *)iter->ent;
80decc70 1118 tp = container_of(event, struct trace_probe, call.event);
413d37d1 1119
687fcc4a 1120 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call));
6e9f23d1 1121
413d37d1 1122 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
85224da0 1123 goto out;
413d37d1 1124
85224da0 1125 trace_seq_puts(s, " <- ");
413d37d1
MH
1126
1127 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
85224da0 1128 goto out;
413d37d1 1129
85224da0 1130 trace_seq_putc(s, ')');
413d37d1 1131
93ccae7a
MH
1132 data = (u8 *)&field[1];
1133 for (i = 0; i < tp->nr_args; i++)
1134 if (!tp->args[i].type->print(s, tp->args[i].name,
e09c8614 1135 data + tp->args[i].offset, field))
85224da0 1136 goto out;
413d37d1 1137
85224da0 1138 trace_seq_putc(s, '\n');
413d37d1 1139
85224da0
SRRH
1140 out:
1141 return trace_handle_return(s);
413d37d1
MH
1142}
1143
413d37d1 1144
2425bcb9 1145static int kprobe_event_define_fields(struct trace_event_call *event_call)
413d37d1
MH
1146{
1147 int ret, i;
93ccae7a 1148 struct kprobe_trace_entry_head field;
c31ffb3f 1149 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
413d37d1 1150
a703d946 1151 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
eca0d916 1152 /* Set argument names as fields */
c31ffb3f
NK
1153 for (i = 0; i < tk->tp.nr_args; i++) {
1154 struct probe_arg *parg = &tk->tp.args[i];
1155
1156 ret = trace_define_field(event_call, parg->type->fmttype,
1157 parg->name,
1158 sizeof(field) + parg->offset,
1159 parg->type->size,
1160 parg->type->is_signed,
93ccae7a
MH
1161 FILTER_OTHER);
1162 if (ret)
1163 return ret;
1164 }
413d37d1
MH
1165 return 0;
1166}
1167
2425bcb9 1168static int kretprobe_event_define_fields(struct trace_event_call *event_call)
413d37d1
MH
1169{
1170 int ret, i;
93ccae7a 1171 struct kretprobe_trace_entry_head field;
c31ffb3f 1172 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;
413d37d1 1173
a703d946
MH
1174 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1175 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
eca0d916 1176 /* Set argument names as fields */
c31ffb3f
NK
1177 for (i = 0; i < tk->tp.nr_args; i++) {
1178 struct probe_arg *parg = &tk->tp.args[i];
1179
1180 ret = trace_define_field(event_call, parg->type->fmttype,
1181 parg->name,
1182 sizeof(field) + parg->offset,
1183 parg->type->size,
1184 parg->type->is_signed,
93ccae7a
MH
1185 FILTER_OTHER);
1186 if (ret)
1187 return ret;
1188 }
413d37d1
MH
1189 return 0;
1190}
1191
07b139c8 1192#ifdef CONFIG_PERF_EVENTS
e08d1c65
MH
1193
1194/* Kprobe profile handler */
f3edacbd 1195static void
c31ffb3f 1196kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
e08d1c65 1197{
2425bcb9 1198 struct trace_event_call *call = &tk->tp.call;
93ccae7a 1199 struct kprobe_trace_entry_head *entry;
1c024eca 1200 struct hlist_head *head;
e09c8614 1201 int size, __size, dsize;
4ed7c92d 1202 int rctx;
e08d1c65 1203
f3edacbd
DM
1204 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1205 return;
2541517c 1206
288e984e
ON
1207 head = this_cpu_ptr(call->perf_events);
1208 if (hlist_empty(head))
f3edacbd 1209 return;
288e984e 1210
c31ffb3f
NK
1211 dsize = __get_data_size(&tk->tp, regs);
1212 __size = sizeof(*entry) + tk->tp.size + dsize;
74ebb63e
MH
1213 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1214 size -= sizeof(u32);
ce71b9df 1215
1e1dcd93 1216 entry = perf_trace_buf_alloc(size, NULL, &rctx);
430ad5a6 1217 if (!entry)
f3edacbd 1218 return;
a1a138d0 1219
c31ffb3f 1220 entry->ip = (unsigned long)tk->rp.kp.addr;
e09c8614 1221 memset(&entry[1], 0, dsize);
c31ffb3f 1222 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1e1dcd93 1223 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
8fd0fbbe 1224 head, NULL);
e08d1c65 1225}
3da0f180 1226NOKPROBE_SYMBOL(kprobe_perf_func);
e08d1c65
MH
1227
1228/* Kretprobe profile handler */
3da0f180 1229static void
c31ffb3f 1230kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
2b106aab 1231 struct pt_regs *regs)
e08d1c65 1232{
2425bcb9 1233 struct trace_event_call *call = &tk->tp.call;
93ccae7a 1234 struct kretprobe_trace_entry_head *entry;
1c024eca 1235 struct hlist_head *head;
e09c8614 1236 int size, __size, dsize;
4ed7c92d 1237 int rctx;
e08d1c65 1238
e87c6bc3 1239 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
2541517c
AS
1240 return;
1241
288e984e
ON
1242 head = this_cpu_ptr(call->perf_events);
1243 if (hlist_empty(head))
1244 return;
1245
c31ffb3f
NK
1246 dsize = __get_data_size(&tk->tp, regs);
1247 __size = sizeof(*entry) + tk->tp.size + dsize;
74ebb63e
MH
1248 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1249 size -= sizeof(u32);
444a2a3b 1250
1e1dcd93 1251 entry = perf_trace_buf_alloc(size, NULL, &rctx);
430ad5a6 1252 if (!entry)
1e12a4a7 1253 return;
e08d1c65 1254
c31ffb3f 1255 entry->func = (unsigned long)tk->rp.kp.addr;
a1a138d0 1256 entry->ret_ip = (unsigned long)ri->ret_addr;
c31ffb3f 1257 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
1e1dcd93 1258 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
8fd0fbbe 1259 head, NULL);
e08d1c65 1260}
3da0f180 1261NOKPROBE_SYMBOL(kretprobe_perf_func);
07b139c8 1262#endif /* CONFIG_PERF_EVENTS */
50d78056 1263
3fe3d619
ON
1264/*
1265 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1266 *
1267 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1268 * lockless, but we can't race with this __init function.
1269 */
2425bcb9 1270static int kprobe_register(struct trace_event_call *event,
fbc1963d 1271 enum trace_reg type, void *data)
2239291a 1272{
c31ffb3f 1273 struct trace_kprobe *tk = (struct trace_kprobe *)event->data;
7f1d2f82 1274 struct trace_event_file *file = data;
1538f888 1275
2239291a
SR
1276 switch (type) {
1277 case TRACE_REG_REGISTER:
c31ffb3f 1278 return enable_trace_kprobe(tk, file);
2239291a 1279 case TRACE_REG_UNREGISTER:
c31ffb3f 1280 return disable_trace_kprobe(tk, file);
2239291a
SR
1281
1282#ifdef CONFIG_PERF_EVENTS
1283 case TRACE_REG_PERF_REGISTER:
c31ffb3f 1284 return enable_trace_kprobe(tk, NULL);
2239291a 1285 case TRACE_REG_PERF_UNREGISTER:
c31ffb3f 1286 return disable_trace_kprobe(tk, NULL);
ceec0b6f
JO
1287 case TRACE_REG_PERF_OPEN:
1288 case TRACE_REG_PERF_CLOSE:
489c75c3
JO
1289 case TRACE_REG_PERF_ADD:
1290 case TRACE_REG_PERF_DEL:
ceec0b6f 1291 return 0;
2239291a
SR
1292#endif
1293 }
1294 return 0;
1295}
50d78056 1296
3da0f180 1297static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
50d78056 1298{
c31ffb3f 1299 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
e08d1c65 1300
a7636d9e 1301 raw_cpu_inc(*tk->nhit);
48182bd2 1302
c31ffb3f
NK
1303 if (tk->tp.flags & TP_FLAG_TRACE)
1304 kprobe_trace_func(tk, regs);
07b139c8 1305#ifdef CONFIG_PERF_EVENTS
c31ffb3f 1306 if (tk->tp.flags & TP_FLAG_PROFILE)
f3edacbd 1307 kprobe_perf_func(tk, regs);
07b139c8 1308#endif
f3edacbd 1309 return 0; /* We don't tweek kernel, so just return 0 */
50d78056 1310}
3da0f180 1311NOKPROBE_SYMBOL(kprobe_dispatcher);
50d78056 1312
3da0f180
MH
1313static int
1314kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
50d78056 1315{
c31ffb3f 1316 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
50d78056 1317
a7636d9e 1318 raw_cpu_inc(*tk->nhit);
48182bd2 1319
c31ffb3f
NK
1320 if (tk->tp.flags & TP_FLAG_TRACE)
1321 kretprobe_trace_func(tk, ri, regs);
07b139c8 1322#ifdef CONFIG_PERF_EVENTS
c31ffb3f
NK
1323 if (tk->tp.flags & TP_FLAG_PROFILE)
1324 kretprobe_perf_func(tk, ri, regs);
07b139c8 1325#endif
50d78056
MH
1326 return 0; /* We don't tweek kernel, so just return 0 */
1327}
3da0f180 1328NOKPROBE_SYMBOL(kretprobe_dispatcher);
e08d1c65 1329
a9a57763
SR
1330static struct trace_event_functions kretprobe_funcs = {
1331 .trace = print_kretprobe_event
1332};
1333
1334static struct trace_event_functions kprobe_funcs = {
1335 .trace = print_kprobe_event
1336};
1337
c31ffb3f 1338static int register_kprobe_event(struct trace_kprobe *tk)
413d37d1 1339{
2425bcb9 1340 struct trace_event_call *call = &tk->tp.call;
413d37d1
MH
1341 int ret;
1342
2425bcb9 1343 /* Initialize trace_event_call */
ffb9f995 1344 INIT_LIST_HEAD(&call->class->fields);
c31ffb3f 1345 if (trace_kprobe_is_return(tk)) {
80decc70 1346 call->event.funcs = &kretprobe_funcs;
2e33af02 1347 call->class->define_fields = kretprobe_event_define_fields;
413d37d1 1348 } else {
80decc70 1349 call->event.funcs = &kprobe_funcs;
2e33af02 1350 call->class->define_fields = kprobe_event_define_fields;
413d37d1 1351 }
5bf652aa 1352 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0)
a342a028 1353 return -ENOMEM;
9023c930 1354 ret = register_trace_event(&call->event);
32c0edae 1355 if (!ret) {
a342a028 1356 kfree(call->print_fmt);
ff50d991 1357 return -ENODEV;
a342a028 1358 }
72cbbc89 1359 call->flags = TRACE_EVENT_FL_KPROBE;
2239291a 1360 call->class->reg = kprobe_register;
c31ffb3f 1361 call->data = tk;
413d37d1 1362 ret = trace_add_event_call(call);
ff50d991 1363 if (ret) {
de7b2973 1364 pr_info("Failed to register kprobe event: %s\n",
687fcc4a 1365 trace_event_name(call));
a342a028 1366 kfree(call->print_fmt);
9023c930 1367 unregister_trace_event(&call->event);
ff50d991 1368 }
413d37d1
MH
1369 return ret;
1370}
1371
c31ffb3f 1372static int unregister_kprobe_event(struct trace_kprobe *tk)
413d37d1 1373{
40c32592
SRRH
1374 int ret;
1375
ff50d991 1376 /* tp->event is unregistered in trace_remove_event_call() */
c31ffb3f 1377 ret = trace_remove_event_call(&tk->tp.call);
40c32592 1378 if (!ret)
c31ffb3f 1379 kfree(tk->tp.call.print_fmt);
40c32592 1380 return ret;
413d37d1
MH
1381}
1382
8434dc93 1383/* Make a tracefs interface for controlling probe points */
413d37d1
MH
1384static __init int init_kprobe_trace(void)
1385{
1386 struct dentry *d_tracer;
1387 struct dentry *entry;
413d37d1 1388
c31ffb3f 1389 if (register_module_notifier(&trace_kprobe_module_nb))
61424318
MH
1390 return -EINVAL;
1391
413d37d1 1392 d_tracer = tracing_init_dentry();
14a5ae40 1393 if (IS_ERR(d_tracer))
413d37d1
MH
1394 return 0;
1395
8434dc93 1396 entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
413d37d1
MH
1397 NULL, &kprobe_events_ops);
1398
cd7e7bd5 1399 /* Event list interface */
413d37d1 1400 if (!entry)
a395d6a7 1401 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
cd7e7bd5
MH
1402
1403 /* Profile interface */
8434dc93 1404 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
cd7e7bd5
MH
1405 NULL, &kprobe_profile_ops);
1406
1407 if (!entry)
a395d6a7 1408 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
413d37d1
MH
1409 return 0;
1410}
1411fs_initcall(init_kprobe_trace);
1412
1413
1414#ifdef CONFIG_FTRACE_STARTUP_TEST
265a5b7e
SR
1415/*
1416 * The "__used" keeps gcc from removing the function symbol
d4d7ccc8
MN
1417 * from the kallsyms table. 'noinline' makes sure that there
1418 * isn't an inlined version used by the test method below
265a5b7e 1419 */
d4d7ccc8
MN
1420static __used __init noinline int
1421kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6)
413d37d1
MH
1422{
1423 return a1 + a2 + a3 + a4 + a5 + a6;
1424}
1425
26a346f2 1426static __init struct trace_event_file *
c31ffb3f 1427find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
41a7dd42 1428{
7f1d2f82 1429 struct trace_event_file *file;
41a7dd42
MH
1430
1431 list_for_each_entry(file, &tr->events, list)
c31ffb3f 1432 if (file->event_call == &tk->tp.call)
41a7dd42
MH
1433 return file;
1434
1435 return NULL;
1436}
1437
3fe3d619 1438/*
c31ffb3f 1439 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
3fe3d619
ON
1440 * stage, we can do this lockless.
1441 */
413d37d1
MH
1442static __init int kprobe_trace_self_tests_init(void)
1443{
231e36f4 1444 int ret, warn = 0;
413d37d1 1445 int (*target)(int, int, int, int, int, int);
c31ffb3f 1446 struct trace_kprobe *tk;
7f1d2f82 1447 struct trace_event_file *file;
413d37d1 1448
748ec3a2
YY
1449 if (tracing_is_disabled())
1450 return -ENODEV;
1451
413d37d1
MH
1452 target = kprobe_trace_selftest_target;
1453
1454 pr_info("Testing kprobe tracing: ");
1455
7e465baa
TZ
1456 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target "
1457 "$stack $stack0 +0($stack)",
1458 create_trace_kprobe);
231e36f4 1459 if (WARN_ON_ONCE(ret)) {
41a7dd42 1460 pr_warn("error on probing function entry.\n");
231e36f4
MH
1461 warn++;
1462 } else {
1463 /* Enable trace point */
c31ffb3f
NK
1464 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1465 if (WARN_ON_ONCE(tk == NULL)) {
41a7dd42 1466 pr_warn("error on getting new probe.\n");
231e36f4 1467 warn++;
41a7dd42 1468 } else {
c31ffb3f 1469 file = find_trace_probe_file(tk, top_trace_array());
41a7dd42
MH
1470 if (WARN_ON_ONCE(file == NULL)) {
1471 pr_warn("error on getting probe file.\n");
1472 warn++;
1473 } else
c31ffb3f 1474 enable_trace_kprobe(tk, file);
41a7dd42 1475 }
231e36f4 1476 }
413d37d1 1477
7e465baa
TZ
1478 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target "
1479 "$retval", create_trace_kprobe);
231e36f4 1480 if (WARN_ON_ONCE(ret)) {
41a7dd42 1481 pr_warn("error on probing function return.\n");
231e36f4
MH
1482 warn++;
1483 } else {
1484 /* Enable trace point */
c31ffb3f
NK
1485 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1486 if (WARN_ON_ONCE(tk == NULL)) {
41a7dd42 1487 pr_warn("error on getting 2nd new probe.\n");
231e36f4 1488 warn++;
41a7dd42 1489 } else {
c31ffb3f 1490 file = find_trace_probe_file(tk, top_trace_array());
41a7dd42
MH
1491 if (WARN_ON_ONCE(file == NULL)) {
1492 pr_warn("error on getting probe file.\n");
1493 warn++;
1494 } else
c31ffb3f 1495 enable_trace_kprobe(tk, file);
41a7dd42 1496 }
231e36f4
MH
1497 }
1498
1499 if (warn)
1500 goto end;
413d37d1
MH
1501
1502 ret = target(1, 2, 3, 4, 5, 6);
1503
d4d7ccc8
MN
1504 /*
1505 * Not expecting an error here, the check is only to prevent the
1506 * optimizer from removing the call to target() as otherwise there
1507 * are no side-effects and the call is never performed.
1508 */
1509 if (ret != 21)
1510 warn++;
1511
02ca1521 1512 /* Disable trace points before removing it */
c31ffb3f
NK
1513 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1514 if (WARN_ON_ONCE(tk == NULL)) {
41a7dd42 1515 pr_warn("error on getting test probe.\n");
02ca1521 1516 warn++;
41a7dd42 1517 } else {
d4d7ccc8
MN
1518 if (trace_kprobe_nhit(tk) != 1) {
1519 pr_warn("incorrect number of testprobe hits\n");
1520 warn++;
1521 }
1522
c31ffb3f 1523 file = find_trace_probe_file(tk, top_trace_array());
41a7dd42
MH
1524 if (WARN_ON_ONCE(file == NULL)) {
1525 pr_warn("error on getting probe file.\n");
1526 warn++;
1527 } else
c31ffb3f 1528 disable_trace_kprobe(tk, file);
41a7dd42 1529 }
02ca1521 1530
c31ffb3f
NK
1531 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1532 if (WARN_ON_ONCE(tk == NULL)) {
41a7dd42 1533 pr_warn("error on getting 2nd test probe.\n");
02ca1521 1534 warn++;
41a7dd42 1535 } else {
d4d7ccc8
MN
1536 if (trace_kprobe_nhit(tk) != 1) {
1537 pr_warn("incorrect number of testprobe2 hits\n");
1538 warn++;
1539 }
1540
c31ffb3f 1541 file = find_trace_probe_file(tk, top_trace_array());
41a7dd42
MH
1542 if (WARN_ON_ONCE(file == NULL)) {
1543 pr_warn("error on getting probe file.\n");
1544 warn++;
1545 } else
c31ffb3f 1546 disable_trace_kprobe(tk, file);
41a7dd42 1547 }
02ca1521 1548
7e465baa 1549 ret = trace_run_command("-:testprobe", create_trace_kprobe);
231e36f4 1550 if (WARN_ON_ONCE(ret)) {
41a7dd42 1551 pr_warn("error on deleting a probe.\n");
231e36f4
MH
1552 warn++;
1553 }
1554
7e465baa 1555 ret = trace_run_command("-:testprobe2", create_trace_kprobe);
231e36f4 1556 if (WARN_ON_ONCE(ret)) {
41a7dd42 1557 pr_warn("error on deleting a probe.\n");
231e36f4
MH
1558 warn++;
1559 }
413d37d1 1560
231e36f4 1561end:
c31ffb3f 1562 release_all_trace_kprobes();
30e7d894
TG
1563 /*
1564 * Wait for the optimizer work to finish. Otherwise it might fiddle
1565 * with probes in already freed __init text.
1566 */
1567 wait_for_kprobe_optimizer();
231e36f4
MH
1568 if (warn)
1569 pr_cont("NG: Some tests are failed. Please check them.\n");
1570 else
1571 pr_cont("OK\n");
413d37d1
MH
1572 return 0;
1573}
1574
1575late_initcall(kprobe_trace_self_tests_init);
1576
1577#endif