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tracing/kprobes: Rename probe_* to trace_probe_*
[linux-2.6.git] / kernel / trace / trace_kprobe.c
blob14b88ed65bb707e489e0b883cc49cfe53d307f89
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
50 const 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 */
62 typedef 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) \
69 static __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 } \
75 static const char PRINT_TYPE_FMT_NAME(type)[] = fmt;
76
77 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, "%x", unsigned int)
78 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "%x", unsigned int)
79 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "%lx", unsigned long)
80 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "%llx", unsigned long long)
81 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d", int)
82 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d", int)
83 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%ld", long)
84 DEFINE_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
92 static inline void *get_rloc_data(u32 *dl)
93 {
94 return (u8 *)dl + get_rloc_offs(*dl);
95 }
96
97 /* For data_loc conversion */
98 static 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 */
111 typedef u32 string;
112 typedef u32 string_size;
113
114 /* Print type function for string type */
115 static __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 }
127 static const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
128
129 /* Data fetch function type */
130 typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
131
132 struct fetch_param {
133 fetch_func_t fn;
134 void *data;
135 };
136
137 static __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) \
149 DEFINE_FETCH_##method(u8) \
150 DEFINE_FETCH_##method(u16) \
151 DEFINE_FETCH_##method(u32) \
152 DEFINE_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) \
165 static __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 }
171 DEFINE_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) \
177 static __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 }
183 DEFINE_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) \
189 static __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 }
194 DEFINE_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) \
200 static __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 }
209 DEFINE_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 */
214 static __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 */
245 static __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 */
268 struct symbol_cache {
269 char *symbol;
270 long offset;
271 unsigned long addr;
272 };
273
274 static 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
282 static void free_symbol_cache(struct symbol_cache *sc)
283 {
284 kfree(sc->symbol);
285 kfree(sc);
286 }
287
288 static 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) \
310 static __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 }
319 DEFINE_BASIC_FETCH_FUNCS(symbol)
320 DEFINE_FETCH_symbol(string)
321 DEFINE_FETCH_symbol(string_size)
322
323 /* Dereference memory access function */
324 struct deref_fetch_param {
325 struct fetch_param orig;
326 long offset;
327 };
328
329 #define DEFINE_FETCH_deref(type) \
330 static __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 }
342 DEFINE_BASIC_FETCH_FUNCS(deref)
343 DEFINE_FETCH_deref(string)
344 DEFINE_FETCH_deref(string_size)
345
346 static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)
347 {
348 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
349 free_deref_fetch_param(data->orig.data);
350 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
351 free_symbol_cache(data->orig.data);
352 kfree(data);
353 }
354
355 /* Bitfield fetch function */
356 struct bitfield_fetch_param {
357 struct fetch_param orig;
358 unsigned char hi_shift;
359 unsigned char low_shift;
360 };
361
362 #define DEFINE_FETCH_bitfield(type) \
363 static __kprobes void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,\
364 void *data, void *dest) \
365 { \
366 struct bitfield_fetch_param *bprm = data; \
367 type buf = 0; \
368 call_fetch(&bprm->orig, regs, &buf); \
369 if (buf) { \
370 buf <<= bprm->hi_shift; \
371 buf >>= bprm->low_shift; \
372 } \
373 *(type *)dest = buf; \
374 }
375 DEFINE_BASIC_FETCH_FUNCS(bitfield)
376 #define fetch_bitfield_string NULL
377 #define fetch_bitfield_string_size NULL
378
379 static __kprobes void
380 free_bitfield_fetch_param(struct bitfield_fetch_param *data)
381 {
382 /*
383 * Don't check the bitfield itself, because this must be the
384 * last fetch function.
385 */
386 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
387 free_deref_fetch_param(data->orig.data);
388 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
389 free_symbol_cache(data->orig.data);
390 kfree(data);
391 }
392 /* Default (unsigned long) fetch type */
393 #define __DEFAULT_FETCH_TYPE(t) u##t
394 #define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
395 #define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
396 #define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
397
398 /* Fetch types */
399 enum {
400 FETCH_MTD_reg = 0,
401 FETCH_MTD_stack,
402 FETCH_MTD_retval,
403 FETCH_MTD_memory,
404 FETCH_MTD_symbol,
405 FETCH_MTD_deref,
406 FETCH_MTD_bitfield,
407 FETCH_MTD_END,
408 };
409
410 #define ASSIGN_FETCH_FUNC(method, type) \
411 [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
412
413 #define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
414 {.name = _name, \
415 .size = _size, \
416 .is_signed = sign, \
417 .print = PRINT_TYPE_FUNC_NAME(ptype), \
418 .fmt = PRINT_TYPE_FMT_NAME(ptype), \
419 .fmttype = _fmttype, \
420 .fetch = { \
421 ASSIGN_FETCH_FUNC(reg, ftype), \
422 ASSIGN_FETCH_FUNC(stack, ftype), \
423 ASSIGN_FETCH_FUNC(retval, ftype), \
424 ASSIGN_FETCH_FUNC(memory, ftype), \
425 ASSIGN_FETCH_FUNC(symbol, ftype), \
426 ASSIGN_FETCH_FUNC(deref, ftype), \
427 ASSIGN_FETCH_FUNC(bitfield, ftype), \
428 } \
429 }
430
431 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign) \
432 __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
433
434 #define FETCH_TYPE_STRING 0
435 #define FETCH_TYPE_STRSIZE 1
436
437 /* Fetch type information table */
438 static const struct fetch_type {
439 const char *name; /* Name of type */
440 size_t size; /* Byte size of type */
441 int is_signed; /* Signed flag */
442 print_type_func_t print; /* Print functions */
443 const char *fmt; /* Fromat string */
444 const char *fmttype; /* Name in format file */
445 /* Fetch functions */
446 fetch_func_t fetch[FETCH_MTD_END];
447 } fetch_type_table[] = {
448 /* Special types */
449 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
450 sizeof(u32), 1, "__data_loc char[]"),
451 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
452 string_size, sizeof(u32), 0, "u32"),
453 /* Basic types */
454 ASSIGN_FETCH_TYPE(u8, u8, 0),
455 ASSIGN_FETCH_TYPE(u16, u16, 0),
456 ASSIGN_FETCH_TYPE(u32, u32, 0),
457 ASSIGN_FETCH_TYPE(u64, u64, 0),
458 ASSIGN_FETCH_TYPE(s8, u8, 1),
459 ASSIGN_FETCH_TYPE(s16, u16, 1),
460 ASSIGN_FETCH_TYPE(s32, u32, 1),
461 ASSIGN_FETCH_TYPE(s64, u64, 1),
462 };
463
464 static const struct fetch_type *find_fetch_type(const char *type)
465 {
466 int i;
467
468 if (!type)
469 type = DEFAULT_FETCH_TYPE_STR;
470
471 /* Special case: bitfield */
472 if (*type == 'b') {
473 unsigned long bs;
474 type = strchr(type, '/');
475 if (!type)
476 goto fail;
477 type++;
478 if (strict_strtoul(type, 0, &bs))
479 goto fail;
480 switch (bs) {
481 case 8:
482 return find_fetch_type("u8");
483 case 16:
484 return find_fetch_type("u16");
485 case 32:
486 return find_fetch_type("u32");
487 case 64:
488 return find_fetch_type("u64");
489 default:
490 goto fail;
491 }
492 }
493
494 for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
495 if (strcmp(type, fetch_type_table[i].name) == 0)
496 return &fetch_type_table[i];
497 fail:
498 return NULL;
499 }
500
501 /* Special function : only accept unsigned long */
502 static __kprobes void fetch_stack_address(struct pt_regs *regs,
503 void *dummy, void *dest)
504 {
505 *(unsigned long *)dest = kernel_stack_pointer(regs);
506 }
507
508 static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
509 fetch_func_t orig_fn)
510 {
511 int i;
512
513 if (type != &fetch_type_table[FETCH_TYPE_STRING])
514 return NULL; /* Only string type needs size function */
515 for (i = 0; i < FETCH_MTD_END; i++)
516 if (type->fetch[i] == orig_fn)
517 return fetch_type_table[FETCH_TYPE_STRSIZE].fetch[i];
518
519 WARN_ON(1); /* This should not happen */
520 return NULL;
521 }
522
523 /**
524 * Kprobe event core functions
525 */
526
527 struct probe_arg {
528 struct fetch_param fetch;
529 struct fetch_param fetch_size;
530 unsigned int offset; /* Offset from argument entry */
531 const char *name; /* Name of this argument */
532 const char *comm; /* Command of this argument */
533 const struct fetch_type *type; /* Type of this argument */
534 };
535
536 /* Flags for trace_probe */
537 #define TP_FLAG_TRACE 1
538 #define TP_FLAG_PROFILE 2
539
540 struct trace_probe {
541 struct list_head list;
542 struct kretprobe rp; /* Use rp.kp for kprobe use */
543 unsigned long nhit;
544 unsigned int flags; /* For TP_FLAG_* */
545 const char *symbol; /* symbol name */
546 struct ftrace_event_class class;
547 struct ftrace_event_call call;
548 ssize_t size; /* trace entry size */
549 unsigned int nr_args;
550 struct probe_arg args[];
551 };
552
553 #define SIZEOF_TRACE_PROBE(n) \
554 (offsetof(struct trace_probe, args) + \
555 (sizeof(struct probe_arg) * (n)))
556
557
558 static __kprobes int trace_probe_is_return(struct trace_probe *tp)
559 {
560 return tp->rp.handler != NULL;
561 }
562
563 static __kprobes const char *trace_probe_symbol(struct trace_probe *tp)
564 {
565 return tp->symbol ? tp->symbol : "unknown";
566 }
567
568 static int register_probe_event(struct trace_probe *tp);
569 static void unregister_probe_event(struct trace_probe *tp);
570
571 static DEFINE_MUTEX(probe_lock);
572 static LIST_HEAD(probe_list);
573
574 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
575 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
576 struct pt_regs *regs);
577
578 /* Check the name is good for event/group/fields */
579 static int is_good_name(const char *name)
580 {
581 if (!isalpha(*name) && *name != '_')
582 return 0;
583 while (*++name != '\0') {
584 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
585 return 0;
586 }
587 return 1;
588 }
589
590 /*
591 * Allocate new trace_probe and initialize it (including kprobes).
592 */
593 static struct trace_probe *alloc_trace_probe(const char *group,
594 const char *event,
595 void *addr,
596 const char *symbol,
597 unsigned long offs,
598 int nargs, int is_return)
599 {
600 struct trace_probe *tp;
601 int ret = -ENOMEM;
602
603 tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
604 if (!tp)
605 return ERR_PTR(ret);
606
607 if (symbol) {
608 tp->symbol = kstrdup(symbol, GFP_KERNEL);
609 if (!tp->symbol)
610 goto error;
611 tp->rp.kp.symbol_name = tp->symbol;
612 tp->rp.kp.offset = offs;
613 } else
614 tp->rp.kp.addr = addr;
615
616 if (is_return)
617 tp->rp.handler = kretprobe_dispatcher;
618 else
619 tp->rp.kp.pre_handler = kprobe_dispatcher;
620
621 if (!event || !is_good_name(event)) {
622 ret = -EINVAL;
623 goto error;
624 }
625
626 tp->call.class = &tp->class;
627 tp->call.name = kstrdup(event, GFP_KERNEL);
628 if (!tp->call.name)
629 goto error;
630
631 if (!group || !is_good_name(group)) {
632 ret = -EINVAL;
633 goto error;
634 }
635
636 tp->class.system = kstrdup(group, GFP_KERNEL);
637 if (!tp->class.system)
638 goto error;
639
640 INIT_LIST_HEAD(&tp->list);
641 return tp;
642 error:
643 kfree(tp->call.name);
644 kfree(tp->symbol);
645 kfree(tp);
646 return ERR_PTR(ret);
647 }
648
649 static void free_probe_arg(struct probe_arg *arg)
650 {
651 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
652 free_bitfield_fetch_param(arg->fetch.data);
653 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
654 free_deref_fetch_param(arg->fetch.data);
655 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
656 free_symbol_cache(arg->fetch.data);
657 kfree(arg->name);
658 kfree(arg->comm);
659 }
660
661 static void free_trace_probe(struct trace_probe *tp)
662 {
663 int i;
664
665 for (i = 0; i < tp->nr_args; i++)
666 free_probe_arg(&tp->args[i]);
667
668 kfree(tp->call.class->system);
669 kfree(tp->call.name);
670 kfree(tp->symbol);
671 kfree(tp);
672 }
673
674 static struct trace_probe *find_trace_probe(const char *event,
675 const char *group)
676 {
677 struct trace_probe *tp;
678
679 list_for_each_entry(tp, &probe_list, list)
680 if (strcmp(tp->call.name, event) == 0 &&
681 strcmp(tp->call.class->system, group) == 0)
682 return tp;
683 return NULL;
684 }
685
686 /* Unregister a trace_probe and probe_event: call with locking probe_lock */
687 static void unregister_trace_probe(struct trace_probe *tp)
688 {
689 if (trace_probe_is_return(tp))
690 unregister_kretprobe(&tp->rp);
691 else
692 unregister_kprobe(&tp->rp.kp);
693 list_del(&tp->list);
694 unregister_probe_event(tp);
695 }
696
697 /* Register a trace_probe and probe_event */
698 static int register_trace_probe(struct trace_probe *tp)
699 {
700 struct trace_probe *old_tp;
701 int ret;
702
703 mutex_lock(&probe_lock);
704
705 /* register as an event */
706 old_tp = find_trace_probe(tp->call.name, tp->call.class->system);
707 if (old_tp) {
708 /* delete old event */
709 unregister_trace_probe(old_tp);
710 free_trace_probe(old_tp);
711 }
712 ret = register_probe_event(tp);
713 if (ret) {
714 pr_warning("Failed to register probe event(%d)\n", ret);
715 goto end;
716 }
717
718 tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
719 if (trace_probe_is_return(tp))
720 ret = register_kretprobe(&tp->rp);
721 else
722 ret = register_kprobe(&tp->rp.kp);
723
724 if (ret) {
725 pr_warning("Could not insert probe(%d)\n", ret);
726 if (ret == -EILSEQ) {
727 pr_warning("Probing address(0x%p) is not an "
728 "instruction boundary.\n",
729 tp->rp.kp.addr);
730 ret = -EINVAL;
731 }
732 unregister_probe_event(tp);
733 } else
734 list_add_tail(&tp->list, &probe_list);
735 end:
736 mutex_unlock(&probe_lock);
737 return ret;
738 }
739
740 /* Split symbol and offset. */
741 static int split_symbol_offset(char *symbol, unsigned long *offset)
742 {
743 char *tmp;
744 int ret;
745
746 if (!offset)
747 return -EINVAL;
748
749 tmp = strchr(symbol, '+');
750 if (tmp) {
751 /* skip sign because strict_strtol doesn't accept '+' */
752 ret = strict_strtoul(tmp + 1, 0, offset);
753 if (ret)
754 return ret;
755 *tmp = '\0';
756 } else
757 *offset = 0;
758 return 0;
759 }
760
761 #define PARAM_MAX_ARGS 16
762 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
763
764 static int parse_probe_vars(char *arg, const struct fetch_type *t,
765 struct fetch_param *f, int is_return)
766 {
767 int ret = 0;
768 unsigned long param;
769
770 if (strcmp(arg, "retval") == 0) {
771 if (is_return)
772 f->fn = t->fetch[FETCH_MTD_retval];
773 else
774 ret = -EINVAL;
775 } else if (strncmp(arg, "stack", 5) == 0) {
776 if (arg[5] == '\0') {
777 if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
778 f->fn = fetch_stack_address;
779 else
780 ret = -EINVAL;
781 } else if (isdigit(arg[5])) {
782 ret = strict_strtoul(arg + 5, 10, &param);
783 if (ret || param > PARAM_MAX_STACK)
784 ret = -EINVAL;
785 else {
786 f->fn = t->fetch[FETCH_MTD_stack];
787 f->data = (void *)param;
788 }
789 } else
790 ret = -EINVAL;
791 } else
792 ret = -EINVAL;
793 return ret;
794 }
795
796 /* Recursive argument parser */
797 static int __parse_probe_arg(char *arg, const struct fetch_type *t,
798 struct fetch_param *f, int is_return)
799 {
800 int ret = 0;
801 unsigned long param;
802 long offset;
803 char *tmp;
804
805 switch (arg[0]) {
806 case '$':
807 ret = parse_probe_vars(arg + 1, t, f, is_return);
808 break;
809 case '%': /* named register */
810 ret = regs_query_register_offset(arg + 1);
811 if (ret >= 0) {
812 f->fn = t->fetch[FETCH_MTD_reg];
813 f->data = (void *)(unsigned long)ret;
814 ret = 0;
815 }
816 break;
817 case '@': /* memory or symbol */
818 if (isdigit(arg[1])) {
819 ret = strict_strtoul(arg + 1, 0, &param);
820 if (ret)
821 break;
822 f->fn = t->fetch[FETCH_MTD_memory];
823 f->data = (void *)param;
824 } else {
825 ret = split_symbol_offset(arg + 1, &offset);
826 if (ret)
827 break;
828 f->data = alloc_symbol_cache(arg + 1, offset);
829 if (f->data)
830 f->fn = t->fetch[FETCH_MTD_symbol];
831 }
832 break;
833 case '+': /* deref memory */
834 arg++; /* Skip '+', because strict_strtol() rejects it. */
835 case '-':
836 tmp = strchr(arg, '(');
837 if (!tmp)
838 break;
839 *tmp = '\0';
840 ret = strict_strtol(arg, 0, &offset);
841 if (ret)
842 break;
843 arg = tmp + 1;
844 tmp = strrchr(arg, ')');
845 if (tmp) {
846 struct deref_fetch_param *dprm;
847 const struct fetch_type *t2 = find_fetch_type(NULL);
848 *tmp = '\0';
849 dprm = kzalloc(sizeof(struct deref_fetch_param),
850 GFP_KERNEL);
851 if (!dprm)
852 return -ENOMEM;
853 dprm->offset = offset;
854 ret = __parse_probe_arg(arg, t2, &dprm->orig,
855 is_return);
856 if (ret)
857 kfree(dprm);
858 else {
859 f->fn = t->fetch[FETCH_MTD_deref];
860 f->data = (void *)dprm;
861 }
862 }
863 break;
864 }
865 if (!ret && !f->fn) { /* Parsed, but do not find fetch method */
866 pr_info("%s type has no corresponding fetch method.\n",
867 t->name);
868 ret = -EINVAL;
869 }
870 return ret;
871 }
872
873 #define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
874
875 /* Bitfield type needs to be parsed into a fetch function */
876 static int __parse_bitfield_probe_arg(const char *bf,
877 const struct fetch_type *t,
878 struct fetch_param *f)
879 {
880 struct bitfield_fetch_param *bprm;
881 unsigned long bw, bo;
882 char *tail;
883
884 if (*bf != 'b')
885 return 0;
886
887 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
888 if (!bprm)
889 return -ENOMEM;
890 bprm->orig = *f;
891 f->fn = t->fetch[FETCH_MTD_bitfield];
892 f->data = (void *)bprm;
893
894 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
895 if (bw == 0 || *tail != '@')
896 return -EINVAL;
897
898 bf = tail + 1;
899 bo = simple_strtoul(bf, &tail, 0);
900 if (tail == bf || *tail != '/')
901 return -EINVAL;
902
903 bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
904 bprm->low_shift = bprm->hi_shift + bo;
905 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
906 }
907
908 /* String length checking wrapper */
909 static int parse_probe_arg(char *arg, struct trace_probe *tp,
910 struct probe_arg *parg, int is_return)
911 {
912 const char *t;
913 int ret;
914
915 if (strlen(arg) > MAX_ARGSTR_LEN) {
916 pr_info("Argument is too long.: %s\n", arg);
917 return -ENOSPC;
918 }
919 parg->comm = kstrdup(arg, GFP_KERNEL);
920 if (!parg->comm) {
921 pr_info("Failed to allocate memory for command '%s'.\n", arg);
922 return -ENOMEM;
923 }
924 t = strchr(parg->comm, ':');
925 if (t) {
926 arg[t - parg->comm] = '\0';
927 t++;
928 }
929 parg->type = find_fetch_type(t);
930 if (!parg->type) {
931 pr_info("Unsupported type: %s\n", t);
932 return -EINVAL;
933 }
934 parg->offset = tp->size;
935 tp->size += parg->type->size;
936 ret = __parse_probe_arg(arg, parg->type, &parg->fetch, is_return);
937 if (ret >= 0 && t != NULL)
938 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
939 if (ret >= 0) {
940 parg->fetch_size.fn = get_fetch_size_function(parg->type,
941 parg->fetch.fn);
942 parg->fetch_size.data = parg->fetch.data;
943 }
944 return ret;
945 }
946
947 /* Return 1 if name is reserved or already used by another argument */
948 static int conflict_field_name(const char *name,
949 struct probe_arg *args, int narg)
950 {
951 int i;
952 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
953 if (strcmp(reserved_field_names[i], name) == 0)
954 return 1;
955 for (i = 0; i < narg; i++)
956 if (strcmp(args[i].name, name) == 0)
957 return 1;
958 return 0;
959 }
960
961 static int create_trace_probe(int argc, char **argv)
962 {
963 /*
964 * Argument syntax:
965 * - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
966 * - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
967 * Fetch args:
968 * $retval : fetch return value
969 * $stack : fetch stack address
970 * $stackN : fetch Nth of stack (N:0-)
971 * @ADDR : fetch memory at ADDR (ADDR should be in kernel)
972 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
973 * %REG : fetch register REG
974 * Dereferencing memory fetch:
975 * +|-offs(ARG) : fetch memory at ARG +|- offs address.
976 * Alias name of args:
977 * NAME=FETCHARG : set NAME as alias of FETCHARG.
978 * Type of args:
979 * FETCHARG:TYPE : use TYPE instead of unsigned long.
980 */
981 struct trace_probe *tp;
982 int i, ret = 0;
983 int is_return = 0, is_delete = 0;
984 char *symbol = NULL, *event = NULL, *group = NULL;
985 char *arg;
986 unsigned long offset = 0;
987 void *addr = NULL;
988 char buf[MAX_EVENT_NAME_LEN];
989
990 /* argc must be >= 1 */
991 if (argv[0][0] == 'p')
992 is_return = 0;
993 else if (argv[0][0] == 'r')
994 is_return = 1;
995 else if (argv[0][0] == '-')
996 is_delete = 1;
997 else {
998 pr_info("Probe definition must be started with 'p', 'r' or"
999 " '-'.\n");
1000 return -EINVAL;
1001 }
1002
1003 if (argv[0][1] == ':') {
1004 event = &argv[0][2];
1005 if (strchr(event, '/')) {
1006 group = event;
1007 event = strchr(group, '/') + 1;
1008 event[-1] = '\0';
1009 if (strlen(group) == 0) {
1010 pr_info("Group name is not specified\n");
1011 return -EINVAL;
1012 }
1013 }
1014 if (strlen(event) == 0) {
1015 pr_info("Event name is not specified\n");
1016 return -EINVAL;
1017 }
1018 }
1019 if (!group)
1020 group = KPROBE_EVENT_SYSTEM;
1021
1022 if (is_delete) {
1023 if (!event) {
1024 pr_info("Delete command needs an event name.\n");
1025 return -EINVAL;
1026 }
1027 mutex_lock(&probe_lock);
1028 tp = find_trace_probe(event, group);
1029 if (!tp) {
1030 mutex_unlock(&probe_lock);
1031 pr_info("Event %s/%s doesn't exist.\n", group, event);
1032 return -ENOENT;
1033 }
1034 /* delete an event */
1035 unregister_trace_probe(tp);
1036 free_trace_probe(tp);
1037 mutex_unlock(&probe_lock);
1038 return 0;
1039 }
1040
1041 if (argc < 2) {
1042 pr_info("Probe point is not specified.\n");
1043 return -EINVAL;
1044 }
1045 if (isdigit(argv[1][0])) {
1046 if (is_return) {
1047 pr_info("Return probe point must be a symbol.\n");
1048 return -EINVAL;
1049 }
1050 /* an address specified */
1051 ret = strict_strtoul(&argv[1][0], 0, (unsigned long *)&addr);
1052 if (ret) {
1053 pr_info("Failed to parse address.\n");
1054 return ret;
1055 }
1056 } else {
1057 /* a symbol specified */
1058 symbol = argv[1];
1059 /* TODO: support .init module functions */
1060 ret = split_symbol_offset(symbol, &offset);
1061 if (ret) {
1062 pr_info("Failed to parse symbol.\n");
1063 return ret;
1064 }
1065 if (offset && is_return) {
1066 pr_info("Return probe must be used without offset.\n");
1067 return -EINVAL;
1068 }
1069 }
1070 argc -= 2; argv += 2;
1071
1072 /* setup a probe */
1073 if (!event) {
1074 /* Make a new event name */
1075 if (symbol)
1076 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
1077 is_return ? 'r' : 'p', symbol, offset);
1078 else
1079 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
1080 is_return ? 'r' : 'p', addr);
1081 event = buf;
1082 }
1083 tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
1084 is_return);
1085 if (IS_ERR(tp)) {
1086 pr_info("Failed to allocate trace_probe.(%d)\n",
1087 (int)PTR_ERR(tp));
1088 return PTR_ERR(tp);
1089 }
1090
1091 /* parse arguments */
1092 ret = 0;
1093 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
1094 /* Increment count for freeing args in error case */
1095 tp->nr_args++;
1096
1097 /* Parse argument name */
1098 arg = strchr(argv[i], '=');
1099 if (arg) {
1100 *arg++ = '\0';
1101 tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
1102 } else {
1103 arg = argv[i];
1104 /* If argument name is omitted, set "argN" */
1105 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
1106 tp->args[i].name = kstrdup(buf, GFP_KERNEL);
1107 }
1108
1109 if (!tp->args[i].name) {
1110 pr_info("Failed to allocate argument[%d] name.\n", i);
1111 ret = -ENOMEM;
1112 goto error;
1113 }
1114
1115 if (!is_good_name(tp->args[i].name)) {
1116 pr_info("Invalid argument[%d] name: %s\n",
1117 i, tp->args[i].name);
1118 ret = -EINVAL;
1119 goto error;
1120 }
1121
1122 if (conflict_field_name(tp->args[i].name, tp->args, i)) {
1123 pr_info("Argument[%d] name '%s' conflicts with "
1124 "another field.\n", i, argv[i]);
1125 ret = -EINVAL;
1126 goto error;
1127 }
1128
1129 /* Parse fetch argument */
1130 ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
1131 if (ret) {
1132 pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
1133 goto error;
1134 }
1135 }
1136
1137 ret = register_trace_probe(tp);
1138 if (ret)
1139 goto error;
1140 return 0;
1141
1142 error:
1143 free_trace_probe(tp);
1144 return ret;
1145 }
1146
1147 static void release_all_trace_probes(void)
1148 {
1149 struct trace_probe *tp;
1150
1151 mutex_lock(&probe_lock);
1152 /* TODO: Use batch unregistration */
1153 while (!list_empty(&probe_list)) {
1154 tp = list_entry(probe_list.next, struct trace_probe, list);
1155 unregister_trace_probe(tp);
1156 free_trace_probe(tp);
1157 }
1158 mutex_unlock(&probe_lock);
1159 }
1160
1161
1162 /* Probes listing interfaces */
1163 static void *probes_seq_start(struct seq_file *m, loff_t *pos)
1164 {
1165 mutex_lock(&probe_lock);
1166 return seq_list_start(&probe_list, *pos);
1167 }
1168
1169 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
1170 {
1171 return seq_list_next(v, &probe_list, pos);
1172 }
1173
1174 static void probes_seq_stop(struct seq_file *m, void *v)
1175 {
1176 mutex_unlock(&probe_lock);
1177 }
1178
1179 static int probes_seq_show(struct seq_file *m, void *v)
1180 {
1181 struct trace_probe *tp = v;
1182 int i;
1183
1184 seq_printf(m, "%c", trace_probe_is_return(tp) ? 'r' : 'p');
1185 seq_printf(m, ":%s/%s", tp->call.class->system, tp->call.name);
1186
1187 if (!tp->symbol)
1188 seq_printf(m, " 0x%p", tp->rp.kp.addr);
1189 else if (tp->rp.kp.offset)
1190 seq_printf(m, " %s+%u", trace_probe_symbol(tp),
1191 tp->rp.kp.offset);
1192 else
1193 seq_printf(m, " %s", trace_probe_symbol(tp));
1194
1195 for (i = 0; i < tp->nr_args; i++)
1196 seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
1197 seq_printf(m, "\n");
1198
1199 return 0;
1200 }
1201
1202 static const struct seq_operations probes_seq_op = {
1203 .start = probes_seq_start,
1204 .next = probes_seq_next,
1205 .stop = probes_seq_stop,
1206 .show = probes_seq_show
1207 };
1208
1209 static int probes_open(struct inode *inode, struct file *file)
1210 {
1211 if ((file->f_mode & FMODE_WRITE) &&
1212 (file->f_flags & O_TRUNC))
1213 release_all_trace_probes();
1214
1215 return seq_open(file, &probes_seq_op);
1216 }
1217
1218 static int command_trace_probe(const char *buf)
1219 {
1220 char **argv;
1221 int argc = 0, ret = 0;
1222
1223 argv = argv_split(GFP_KERNEL, buf, &argc);
1224 if (!argv)
1225 return -ENOMEM;
1226
1227 if (argc)
1228 ret = create_trace_probe(argc, argv);
1229
1230 argv_free(argv);
1231 return ret;
1232 }
1233
1234 #define WRITE_BUFSIZE 4096
1235
1236 static ssize_t probes_write(struct file *file, const char __user *buffer,
1237 size_t count, loff_t *ppos)
1238 {
1239 char *kbuf, *tmp;
1240 int ret;
1241 size_t done;
1242 size_t size;
1243
1244 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
1245 if (!kbuf)
1246 return -ENOMEM;
1247
1248 ret = done = 0;
1249 while (done < count) {
1250 size = count - done;
1251 if (size >= WRITE_BUFSIZE)
1252 size = WRITE_BUFSIZE - 1;
1253 if (copy_from_user(kbuf, buffer + done, size)) {
1254 ret = -EFAULT;
1255 goto out;
1256 }
1257 kbuf[size] = '\0';
1258 tmp = strchr(kbuf, '\n');
1259 if (tmp) {
1260 *tmp = '\0';
1261 size = tmp - kbuf + 1;
1262 } else if (done + size < count) {
1263 pr_warning("Line length is too long: "
1264 "Should be less than %d.", WRITE_BUFSIZE);
1265 ret = -EINVAL;
1266 goto out;
1267 }
1268 done += size;
1269 /* Remove comments */
1270 tmp = strchr(kbuf, '#');
1271 if (tmp)
1272 *tmp = '\0';
1273
1274 ret = command_trace_probe(kbuf);
1275 if (ret)
1276 goto out;
1277 }
1278 ret = done;
1279 out:
1280 kfree(kbuf);
1281 return ret;
1282 }
1283
1284 static const struct file_operations kprobe_events_ops = {
1285 .owner = THIS_MODULE,
1286 .open = probes_open,
1287 .read = seq_read,
1288 .llseek = seq_lseek,
1289 .release = seq_release,
1290 .write = probes_write,
1291 };
1292
1293 /* Probes profiling interfaces */
1294 static int probes_profile_seq_show(struct seq_file *m, void *v)
1295 {
1296 struct trace_probe *tp = v;
1297
1298 seq_printf(m, " %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
1299 tp->rp.kp.nmissed);
1300
1301 return 0;
1302 }
1303
1304 static const struct seq_operations profile_seq_op = {
1305 .start = probes_seq_start,
1306 .next = probes_seq_next,
1307 .stop = probes_seq_stop,
1308 .show = probes_profile_seq_show
1309 };
1310
1311 static int profile_open(struct inode *inode, struct file *file)
1312 {
1313 return seq_open(file, &profile_seq_op);
1314 }
1315
1316 static const struct file_operations kprobe_profile_ops = {
1317 .owner = THIS_MODULE,
1318 .open = profile_open,
1319 .read = seq_read,
1320 .llseek = seq_lseek,
1321 .release = seq_release,
1322 };
1323
1324 /* Sum up total data length for dynamic arraies (strings) */
1325 static __kprobes int __get_data_size(struct trace_probe *tp,
1326 struct pt_regs *regs)
1327 {
1328 int i, ret = 0;
1329 u32 len;
1330
1331 for (i = 0; i < tp->nr_args; i++)
1332 if (unlikely(tp->args[i].fetch_size.fn)) {
1333 call_fetch(&tp->args[i].fetch_size, regs, &len);
1334 ret += len;
1335 }
1336
1337 return ret;
1338 }
1339
1340 /* Store the value of each argument */
1341 static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
1342 struct pt_regs *regs,
1343 u8 *data, int maxlen)
1344 {
1345 int i;
1346 u32 end = tp->size;
1347 u32 *dl; /* Data (relative) location */
1348
1349 for (i = 0; i < tp->nr_args; i++) {
1350 if (unlikely(tp->args[i].fetch_size.fn)) {
1351 /*
1352 * First, we set the relative location and
1353 * maximum data length to *dl
1354 */
1355 dl = (u32 *)(data + tp->args[i].offset);
1356 *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
1357 /* Then try to fetch string or dynamic array data */
1358 call_fetch(&tp->args[i].fetch, regs, dl);
1359 /* Reduce maximum length */
1360 end += get_rloc_len(*dl);
1361 maxlen -= get_rloc_len(*dl);
1362 /* Trick here, convert data_rloc to data_loc */
1363 *dl = convert_rloc_to_loc(*dl,
1364 ent_size + tp->args[i].offset);
1365 } else
1366 /* Just fetching data normally */
1367 call_fetch(&tp->args[i].fetch, regs,
1368 data + tp->args[i].offset);
1369 }
1370 }
1371
1372 /* Kprobe handler */
1373 static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
1374 {
1375 struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1376 struct kprobe_trace_entry_head *entry;
1377 struct ring_buffer_event *event;
1378 struct ring_buffer *buffer;
1379 int size, dsize, pc;
1380 unsigned long irq_flags;
1381 struct ftrace_event_call *call = &tp->call;
1382
1383 tp->nhit++;
1384
1385 local_save_flags(irq_flags);
1386 pc = preempt_count();
1387
1388 dsize = __get_data_size(tp, regs);
1389 size = sizeof(*entry) + tp->size + dsize;
1390
1391 event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1392 size, irq_flags, pc);
1393 if (!event)
1394 return;
1395
1396 entry = ring_buffer_event_data(event);
1397 entry->ip = (unsigned long)kp->addr;
1398 store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1399
1400 if (!filter_current_check_discard(buffer, call, entry, event))
1401 trace_nowake_buffer_unlock_commit_regs(buffer, event,
1402 irq_flags, pc, regs);
1403 }
1404
1405 /* Kretprobe handler */
1406 static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
1407 struct pt_regs *regs)
1408 {
1409 struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1410 struct kretprobe_trace_entry_head *entry;
1411 struct ring_buffer_event *event;
1412 struct ring_buffer *buffer;
1413 int size, pc, dsize;
1414 unsigned long irq_flags;
1415 struct ftrace_event_call *call = &tp->call;
1416
1417 local_save_flags(irq_flags);
1418 pc = preempt_count();
1419
1420 dsize = __get_data_size(tp, regs);
1421 size = sizeof(*entry) + tp->size + dsize;
1422
1423 event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1424 size, irq_flags, pc);
1425 if (!event)
1426 return;
1427
1428 entry = ring_buffer_event_data(event);
1429 entry->func = (unsigned long)tp->rp.kp.addr;
1430 entry->ret_ip = (unsigned long)ri->ret_addr;
1431 store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1432
1433 if (!filter_current_check_discard(buffer, call, entry, event))
1434 trace_nowake_buffer_unlock_commit_regs(buffer, event,
1435 irq_flags, pc, regs);
1436 }
1437
1438 /* Event entry printers */
1439 enum print_line_t
1440 print_kprobe_event(struct trace_iterator *iter, int flags,
1441 struct trace_event *event)
1442 {
1443 struct kprobe_trace_entry_head *field;
1444 struct trace_seq *s = &iter->seq;
1445 struct trace_probe *tp;
1446 u8 *data;
1447 int i;
1448
1449 field = (struct kprobe_trace_entry_head *)iter->ent;
1450 tp = container_of(event, struct trace_probe, call.event);
1451
1452 if (!trace_seq_printf(s, "%s: (", tp->call.name))
1453 goto partial;
1454
1455 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1456 goto partial;
1457
1458 if (!trace_seq_puts(s, ")"))
1459 goto partial;
1460
1461 data = (u8 *)&field[1];
1462 for (i = 0; i < tp->nr_args; i++)
1463 if (!tp->args[i].type->print(s, tp->args[i].name,
1464 data + tp->args[i].offset, field))
1465 goto partial;
1466
1467 if (!trace_seq_puts(s, "\n"))
1468 goto partial;
1469
1470 return TRACE_TYPE_HANDLED;
1471 partial:
1472 return TRACE_TYPE_PARTIAL_LINE;
1473 }
1474
1475 enum print_line_t
1476 print_kretprobe_event(struct trace_iterator *iter, int flags,
1477 struct trace_event *event)
1478 {
1479 struct kretprobe_trace_entry_head *field;
1480 struct trace_seq *s = &iter->seq;
1481 struct trace_probe *tp;
1482 u8 *data;
1483 int i;
1484
1485 field = (struct kretprobe_trace_entry_head *)iter->ent;
1486 tp = container_of(event, struct trace_probe, call.event);
1487
1488 if (!trace_seq_printf(s, "%s: (", tp->call.name))
1489 goto partial;
1490
1491 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1492 goto partial;
1493
1494 if (!trace_seq_puts(s, " <- "))
1495 goto partial;
1496
1497 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1498 goto partial;
1499
1500 if (!trace_seq_puts(s, ")"))
1501 goto partial;
1502
1503 data = (u8 *)&field[1];
1504 for (i = 0; i < tp->nr_args; i++)
1505 if (!tp->args[i].type->print(s, tp->args[i].name,
1506 data + tp->args[i].offset, field))
1507 goto partial;
1508
1509 if (!trace_seq_puts(s, "\n"))
1510 goto partial;
1511
1512 return TRACE_TYPE_HANDLED;
1513 partial:
1514 return TRACE_TYPE_PARTIAL_LINE;
1515 }
1516
1517 static int probe_event_enable(struct ftrace_event_call *call)
1518 {
1519 struct trace_probe *tp = (struct trace_probe *)call->data;
1520
1521 tp->flags |= TP_FLAG_TRACE;
1522 if (trace_probe_is_return(tp))
1523 return enable_kretprobe(&tp->rp);
1524 else
1525 return enable_kprobe(&tp->rp.kp);
1526 }
1527
1528 static void probe_event_disable(struct ftrace_event_call *call)
1529 {
1530 struct trace_probe *tp = (struct trace_probe *)call->data;
1531
1532 tp->flags &= ~TP_FLAG_TRACE;
1533 if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
1534 if (trace_probe_is_return(tp))
1535 disable_kretprobe(&tp->rp);
1536 else
1537 disable_kprobe(&tp->rp.kp);
1538 }
1539 }
1540
1541 #undef DEFINE_FIELD
1542 #define DEFINE_FIELD(type, item, name, is_signed) \
1543 do { \
1544 ret = trace_define_field(event_call, #type, name, \
1545 offsetof(typeof(field), item), \
1546 sizeof(field.item), is_signed, \
1547 FILTER_OTHER); \
1548 if (ret) \
1549 return ret; \
1550 } while (0)
1551
1552 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1553 {
1554 int ret, i;
1555 struct kprobe_trace_entry_head field;
1556 struct trace_probe *tp = (struct trace_probe *)event_call->data;
1557
1558 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1559 /* Set argument names as fields */
1560 for (i = 0; i < tp->nr_args; i++) {
1561 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1562 tp->args[i].name,
1563 sizeof(field) + tp->args[i].offset,
1564 tp->args[i].type->size,
1565 tp->args[i].type->is_signed,
1566 FILTER_OTHER);
1567 if (ret)
1568 return ret;
1569 }
1570 return 0;
1571 }
1572
1573 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1574 {
1575 int ret, i;
1576 struct kretprobe_trace_entry_head field;
1577 struct trace_probe *tp = (struct trace_probe *)event_call->data;
1578
1579 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1580 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1581 /* Set argument names as fields */
1582 for (i = 0; i < tp->nr_args; i++) {
1583 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1584 tp->args[i].name,
1585 sizeof(field) + tp->args[i].offset,
1586 tp->args[i].type->size,
1587 tp->args[i].type->is_signed,
1588 FILTER_OTHER);
1589 if (ret)
1590 return ret;
1591 }
1592 return 0;
1593 }
1594
1595 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
1596 {
1597 int i;
1598 int pos = 0;
1599
1600 const char *fmt, *arg;
1601
1602 if (!trace_probe_is_return(tp)) {
1603 fmt = "(%lx)";
1604 arg = "REC->" FIELD_STRING_IP;
1605 } else {
1606 fmt = "(%lx <- %lx)";
1607 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1608 }
1609
1610 /* When len=0, we just calculate the needed length */
1611 #define LEN_OR_ZERO (len ? len - pos : 0)
1612
1613 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1614
1615 for (i = 0; i < tp->nr_args; i++) {
1616 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
1617 tp->args[i].name, tp->args[i].type->fmt);
1618 }
1619
1620 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
1621
1622 for (i = 0; i < tp->nr_args; i++) {
1623 if (strcmp(tp->args[i].type->name, "string") == 0)
1624 pos += snprintf(buf + pos, LEN_OR_ZERO,
1625 ", __get_str(%s)",
1626 tp->args[i].name);
1627 else
1628 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
1629 tp->args[i].name);
1630 }
1631
1632 #undef LEN_OR_ZERO
1633
1634 /* return the length of print_fmt */
1635 return pos;
1636 }
1637
1638 static int set_print_fmt(struct trace_probe *tp)
1639 {
1640 int len;
1641 char *print_fmt;
1642
1643 /* First: called with 0 length to calculate the needed length */
1644 len = __set_print_fmt(tp, NULL, 0);
1645 print_fmt = kmalloc(len + 1, GFP_KERNEL);
1646 if (!print_fmt)
1647 return -ENOMEM;
1648
1649 /* Second: actually write the @print_fmt */
1650 __set_print_fmt(tp, print_fmt, len + 1);
1651 tp->call.print_fmt = print_fmt;
1652
1653 return 0;
1654 }
1655
1656 #ifdef CONFIG_PERF_EVENTS
1657
1658 /* Kprobe profile handler */
1659 static __kprobes void kprobe_perf_func(struct kprobe *kp,
1660 struct pt_regs *regs)
1661 {
1662 struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1663 struct ftrace_event_call *call = &tp->call;
1664 struct kprobe_trace_entry_head *entry;
1665 struct hlist_head *head;
1666 int size, __size, dsize;
1667 int rctx;
1668
1669 dsize = __get_data_size(tp, regs);
1670 __size = sizeof(*entry) + tp->size + dsize;
1671 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1672 size -= sizeof(u32);
1673 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1674 "profile buffer not large enough"))
1675 return;
1676
1677 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1678 if (!entry)
1679 return;
1680
1681 entry->ip = (unsigned long)kp->addr;
1682 memset(&entry[1], 0, dsize);
1683 store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1684
1685 head = this_cpu_ptr(call->perf_events);
1686 perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
1687 }
1688
1689 /* Kretprobe profile handler */
1690 static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
1691 struct pt_regs *regs)
1692 {
1693 struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1694 struct ftrace_event_call *call = &tp->call;
1695 struct kretprobe_trace_entry_head *entry;
1696 struct hlist_head *head;
1697 int size, __size, dsize;
1698 int rctx;
1699
1700 dsize = __get_data_size(tp, regs);
1701 __size = sizeof(*entry) + tp->size + dsize;
1702 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1703 size -= sizeof(u32);
1704 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1705 "profile buffer not large enough"))
1706 return;
1707
1708 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1709 if (!entry)
1710 return;
1711
1712 entry->func = (unsigned long)tp->rp.kp.addr;
1713 entry->ret_ip = (unsigned long)ri->ret_addr;
1714 store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1715
1716 head = this_cpu_ptr(call->perf_events);
1717 perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
1718 }
1719
1720 static int probe_perf_enable(struct ftrace_event_call *call)
1721 {
1722 struct trace_probe *tp = (struct trace_probe *)call->data;
1723
1724 tp->flags |= TP_FLAG_PROFILE;
1725
1726 if (trace_probe_is_return(tp))
1727 return enable_kretprobe(&tp->rp);
1728 else
1729 return enable_kprobe(&tp->rp.kp);
1730 }
1731
1732 static void probe_perf_disable(struct ftrace_event_call *call)
1733 {
1734 struct trace_probe *tp = (struct trace_probe *)call->data;
1735
1736 tp->flags &= ~TP_FLAG_PROFILE;
1737
1738 if (!(tp->flags & TP_FLAG_TRACE)) {
1739 if (trace_probe_is_return(tp))
1740 disable_kretprobe(&tp->rp);
1741 else
1742 disable_kprobe(&tp->rp.kp);
1743 }
1744 }
1745 #endif /* CONFIG_PERF_EVENTS */
1746
1747 static __kprobes
1748 int kprobe_register(struct ftrace_event_call *event, enum trace_reg type)
1749 {
1750 switch (type) {
1751 case TRACE_REG_REGISTER:
1752 return probe_event_enable(event);
1753 case TRACE_REG_UNREGISTER:
1754 probe_event_disable(event);
1755 return 0;
1756
1757 #ifdef CONFIG_PERF_EVENTS
1758 case TRACE_REG_PERF_REGISTER:
1759 return probe_perf_enable(event);
1760 case TRACE_REG_PERF_UNREGISTER:
1761 probe_perf_disable(event);
1762 return 0;
1763 #endif
1764 }
1765 return 0;
1766 }
1767
1768 static __kprobes
1769 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1770 {
1771 struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1772
1773 if (tp->flags & TP_FLAG_TRACE)
1774 kprobe_trace_func(kp, regs);
1775 #ifdef CONFIG_PERF_EVENTS
1776 if (tp->flags & TP_FLAG_PROFILE)
1777 kprobe_perf_func(kp, regs);
1778 #endif
1779 return 0; /* We don't tweek kernel, so just return 0 */
1780 }
1781
1782 static __kprobes
1783 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1784 {
1785 struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1786
1787 if (tp->flags & TP_FLAG_TRACE)
1788 kretprobe_trace_func(ri, regs);
1789 #ifdef CONFIG_PERF_EVENTS
1790 if (tp->flags & TP_FLAG_PROFILE)
1791 kretprobe_perf_func(ri, regs);
1792 #endif
1793 return 0; /* We don't tweek kernel, so just return 0 */
1794 }
1795
1796 static struct trace_event_functions kretprobe_funcs = {
1797 .trace = print_kretprobe_event
1798 };
1799
1800 static struct trace_event_functions kprobe_funcs = {
1801 .trace = print_kprobe_event
1802 };
1803
1804 static int register_probe_event(struct trace_probe *tp)
1805 {
1806 struct ftrace_event_call *call = &tp->call;
1807 int ret;
1808
1809 /* Initialize ftrace_event_call */
1810 INIT_LIST_HEAD(&call->class->fields);
1811 if (trace_probe_is_return(tp)) {
1812 call->event.funcs = &kretprobe_funcs;
1813 call->class->define_fields = kretprobe_event_define_fields;
1814 } else {
1815 call->event.funcs = &kprobe_funcs;
1816 call->class->define_fields = kprobe_event_define_fields;
1817 }
1818 if (set_print_fmt(tp) < 0)
1819 return -ENOMEM;
1820 ret = register_ftrace_event(&call->event);
1821 if (!ret) {
1822 kfree(call->print_fmt);
1823 return -ENODEV;
1824 }
1825 call->flags = 0;
1826 call->class->reg = kprobe_register;
1827 call->data = tp;
1828 ret = trace_add_event_call(call);
1829 if (ret) {
1830 pr_info("Failed to register kprobe event: %s\n", call->name);
1831 kfree(call->print_fmt);
1832 unregister_ftrace_event(&call->event);
1833 }
1834 return ret;
1835 }
1836
1837 static void unregister_probe_event(struct trace_probe *tp)
1838 {
1839 /* tp->event is unregistered in trace_remove_event_call() */
1840 trace_remove_event_call(&tp->call);
1841 kfree(tp->call.print_fmt);
1842 }
1843
1844 /* Make a debugfs interface for controlling probe points */
1845 static __init int init_kprobe_trace(void)
1846 {
1847 struct dentry *d_tracer;
1848 struct dentry *entry;
1849
1850 d_tracer = tracing_init_dentry();
1851 if (!d_tracer)
1852 return 0;
1853
1854 entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1855 NULL, &kprobe_events_ops);
1856
1857 /* Event list interface */
1858 if (!entry)
1859 pr_warning("Could not create debugfs "
1860 "'kprobe_events' entry\n");
1861
1862 /* Profile interface */
1863 entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1864 NULL, &kprobe_profile_ops);
1865
1866 if (!entry)
1867 pr_warning("Could not create debugfs "
1868 "'kprobe_profile' entry\n");
1869 return 0;
1870 }
1871 fs_initcall(init_kprobe_trace);
1872
1873
1874 #ifdef CONFIG_FTRACE_STARTUP_TEST
1875
1876 /*
1877 * The "__used" keeps gcc from removing the function symbol
1878 * from the kallsyms table.
1879 */
1880 static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1881 int a4, int a5, int a6)
1882 {
1883 return a1 + a2 + a3 + a4 + a5 + a6;
1884 }
1885
1886 static __init int kprobe_trace_self_tests_init(void)
1887 {
1888 int ret, warn = 0;
1889 int (*target)(int, int, int, int, int, int);
1890 struct trace_probe *tp;
1891
1892 target = kprobe_trace_selftest_target;
1893
1894 pr_info("Testing kprobe tracing: ");
1895
1896 ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1897 "$stack $stack0 +0($stack)");
1898 if (WARN_ON_ONCE(ret)) {
1899 pr_warning("error on probing function entry.\n");
1900 warn++;
1901 } else {
1902 /* Enable trace point */
1903 tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM);
1904 if (WARN_ON_ONCE(tp == NULL)) {
1905 pr_warning("error on getting new probe.\n");
1906 warn++;
1907 } else
1908 probe_event_enable(&tp->call);
1909 }
1910
1911 ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1912 "$retval");
1913 if (WARN_ON_ONCE(ret)) {
1914 pr_warning("error on probing function return.\n");
1915 warn++;
1916 } else {
1917 /* Enable trace point */
1918 tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM);
1919 if (WARN_ON_ONCE(tp == NULL)) {
1920 pr_warning("error on getting new probe.\n");
1921 warn++;
1922 } else
1923 probe_event_enable(&tp->call);
1924 }
1925
1926 if (warn)
1927 goto end;
1928
1929 ret = target(1, 2, 3, 4, 5, 6);
1930
1931 ret = command_trace_probe("-:testprobe");
1932 if (WARN_ON_ONCE(ret)) {
1933 pr_warning("error on deleting a probe.\n");
1934 warn++;
1935 }
1936
1937 ret = command_trace_probe("-:testprobe2");
1938 if (WARN_ON_ONCE(ret)) {
1939 pr_warning("error on deleting a probe.\n");
1940 warn++;
1941 }
1942
1943 end:
1944 release_all_trace_probes();
1945 if (warn)
1946 pr_cont("NG: Some tests are failed. Please check them.\n");
1947 else
1948 pr_cont("OK\n");
1949 return 0;
1950 }
1951
1952 late_initcall(kprobe_trace_self_tests_init);
1953
1954 #endif
Linus' kernel tree