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Merge ssh://master.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6...
[deliverable/linux.git] / kernel / trace / trace_kprobe.c
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 probe_is_return(struct trace_probe *tp)
559 {
560 return tp->rp.handler != NULL;
561 }
562
563 static __kprobes const char *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_probe_event(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 (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_probe_event(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 (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_probe_event(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 cleanup_all_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", 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", probe_symbol(tp), tp->rp.kp.offset);
1191 else
1192 seq_printf(m, " %s", probe_symbol(tp));
1193
1194 for (i = 0; i < tp->nr_args; i++)
1195 seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
1196 seq_printf(m, "\n");
1197
1198 return 0;
1199 }
1200
1201 static const struct seq_operations probes_seq_op = {
1202 .start = probes_seq_start,
1203 .next = probes_seq_next,
1204 .stop = probes_seq_stop,
1205 .show = probes_seq_show
1206 };
1207
1208 static int probes_open(struct inode *inode, struct file *file)
1209 {
1210 if ((file->f_mode & FMODE_WRITE) &&
1211 (file->f_flags & O_TRUNC))
1212 cleanup_all_probes();
1213
1214 return seq_open(file, &probes_seq_op);
1215 }
1216
1217 static int command_trace_probe(const char *buf)
1218 {
1219 char **argv;
1220 int argc = 0, ret = 0;
1221
1222 argv = argv_split(GFP_KERNEL, buf, &argc);
1223 if (!argv)
1224 return -ENOMEM;
1225
1226 if (argc)
1227 ret = create_trace_probe(argc, argv);
1228
1229 argv_free(argv);
1230 return ret;
1231 }
1232
1233 #define WRITE_BUFSIZE 4096
1234
1235 static ssize_t probes_write(struct file *file, const char __user *buffer,
1236 size_t count, loff_t *ppos)
1237 {
1238 char *kbuf, *tmp;
1239 int ret;
1240 size_t done;
1241 size_t size;
1242
1243 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
1244 if (!kbuf)
1245 return -ENOMEM;
1246
1247 ret = done = 0;
1248 while (done < count) {
1249 size = count - done;
1250 if (size >= WRITE_BUFSIZE)
1251 size = WRITE_BUFSIZE - 1;
1252 if (copy_from_user(kbuf, buffer + done, size)) {
1253 ret = -EFAULT;
1254 goto out;
1255 }
1256 kbuf[size] = '\0';
1257 tmp = strchr(kbuf, '\n');
1258 if (tmp) {
1259 *tmp = '\0';
1260 size = tmp - kbuf + 1;
1261 } else if (done + size < count) {
1262 pr_warning("Line length is too long: "
1263 "Should be less than %d.", WRITE_BUFSIZE);
1264 ret = -EINVAL;
1265 goto out;
1266 }
1267 done += size;
1268 /* Remove comments */
1269 tmp = strchr(kbuf, '#');
1270 if (tmp)
1271 *tmp = '\0';
1272
1273 ret = command_trace_probe(kbuf);
1274 if (ret)
1275 goto out;
1276 }
1277 ret = done;
1278 out:
1279 kfree(kbuf);
1280 return ret;
1281 }
1282
1283 static const struct file_operations kprobe_events_ops = {
1284 .owner = THIS_MODULE,
1285 .open = probes_open,
1286 .read = seq_read,
1287 .llseek = seq_lseek,
1288 .release = seq_release,
1289 .write = probes_write,
1290 };
1291
1292 /* Probes profiling interfaces */
1293 static int probes_profile_seq_show(struct seq_file *m, void *v)
1294 {
1295 struct trace_probe *tp = v;
1296
1297 seq_printf(m, " %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
1298 tp->rp.kp.nmissed);
1299
1300 return 0;
1301 }
1302
1303 static const struct seq_operations profile_seq_op = {
1304 .start = probes_seq_start,
1305 .next = probes_seq_next,
1306 .stop = probes_seq_stop,
1307 .show = probes_profile_seq_show
1308 };
1309
1310 static int profile_open(struct inode *inode, struct file *file)
1311 {
1312 return seq_open(file, &profile_seq_op);
1313 }
1314
1315 static const struct file_operations kprobe_profile_ops = {
1316 .owner = THIS_MODULE,
1317 .open = profile_open,
1318 .read = seq_read,
1319 .llseek = seq_lseek,
1320 .release = seq_release,
1321 };
1322
1323 /* Sum up total data length for dynamic arraies (strings) */
1324 static __kprobes int __get_data_size(struct trace_probe *tp,
1325 struct pt_regs *regs)
1326 {
1327 int i, ret = 0;
1328 u32 len;
1329
1330 for (i = 0; i < tp->nr_args; i++)
1331 if (unlikely(tp->args[i].fetch_size.fn)) {
1332 call_fetch(&tp->args[i].fetch_size, regs, &len);
1333 ret += len;
1334 }
1335
1336 return ret;
1337 }
1338
1339 /* Store the value of each argument */
1340 static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
1341 struct pt_regs *regs,
1342 u8 *data, int maxlen)
1343 {
1344 int i;
1345 u32 end = tp->size;
1346 u32 *dl; /* Data (relative) location */
1347
1348 for (i = 0; i < tp->nr_args; i++) {
1349 if (unlikely(tp->args[i].fetch_size.fn)) {
1350 /*
1351 * First, we set the relative location and
1352 * maximum data length to *dl
1353 */
1354 dl = (u32 *)(data + tp->args[i].offset);
1355 *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
1356 /* Then try to fetch string or dynamic array data */
1357 call_fetch(&tp->args[i].fetch, regs, dl);
1358 /* Reduce maximum length */
1359 end += get_rloc_len(*dl);
1360 maxlen -= get_rloc_len(*dl);
1361 /* Trick here, convert data_rloc to data_loc */
1362 *dl = convert_rloc_to_loc(*dl,
1363 ent_size + tp->args[i].offset);
1364 } else
1365 /* Just fetching data normally */
1366 call_fetch(&tp->args[i].fetch, regs,
1367 data + tp->args[i].offset);
1368 }
1369 }
1370
1371 /* Kprobe handler */
1372 static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
1373 {
1374 struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1375 struct kprobe_trace_entry_head *entry;
1376 struct ring_buffer_event *event;
1377 struct ring_buffer *buffer;
1378 int size, dsize, pc;
1379 unsigned long irq_flags;
1380 struct ftrace_event_call *call = &tp->call;
1381
1382 tp->nhit++;
1383
1384 local_save_flags(irq_flags);
1385 pc = preempt_count();
1386
1387 dsize = __get_data_size(tp, regs);
1388 size = sizeof(*entry) + tp->size + dsize;
1389
1390 event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1391 size, irq_flags, pc);
1392 if (!event)
1393 return;
1394
1395 entry = ring_buffer_event_data(event);
1396 entry->ip = (unsigned long)kp->addr;
1397 store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1398
1399 if (!filter_current_check_discard(buffer, call, entry, event))
1400 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1401 }
1402
1403 /* Kretprobe handler */
1404 static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
1405 struct pt_regs *regs)
1406 {
1407 struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1408 struct kretprobe_trace_entry_head *entry;
1409 struct ring_buffer_event *event;
1410 struct ring_buffer *buffer;
1411 int size, pc, dsize;
1412 unsigned long irq_flags;
1413 struct ftrace_event_call *call = &tp->call;
1414
1415 local_save_flags(irq_flags);
1416 pc = preempt_count();
1417
1418 dsize = __get_data_size(tp, regs);
1419 size = sizeof(*entry) + tp->size + dsize;
1420
1421 event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1422 size, irq_flags, pc);
1423 if (!event)
1424 return;
1425
1426 entry = ring_buffer_event_data(event);
1427 entry->func = (unsigned long)tp->rp.kp.addr;
1428 entry->ret_ip = (unsigned long)ri->ret_addr;
1429 store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1430
1431 if (!filter_current_check_discard(buffer, call, entry, event))
1432 trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1433 }
1434
1435 /* Event entry printers */
1436 enum print_line_t
1437 print_kprobe_event(struct trace_iterator *iter, int flags,
1438 struct trace_event *event)
1439 {
1440 struct kprobe_trace_entry_head *field;
1441 struct trace_seq *s = &iter->seq;
1442 struct trace_probe *tp;
1443 u8 *data;
1444 int i;
1445
1446 field = (struct kprobe_trace_entry_head *)iter->ent;
1447 tp = container_of(event, struct trace_probe, call.event);
1448
1449 if (!trace_seq_printf(s, "%s: (", tp->call.name))
1450 goto partial;
1451
1452 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1453 goto partial;
1454
1455 if (!trace_seq_puts(s, ")"))
1456 goto partial;
1457
1458 data = (u8 *)&field[1];
1459 for (i = 0; i < tp->nr_args; i++)
1460 if (!tp->args[i].type->print(s, tp->args[i].name,
1461 data + tp->args[i].offset, field))
1462 goto partial;
1463
1464 if (!trace_seq_puts(s, "\n"))
1465 goto partial;
1466
1467 return TRACE_TYPE_HANDLED;
1468 partial:
1469 return TRACE_TYPE_PARTIAL_LINE;
1470 }
1471
1472 enum print_line_t
1473 print_kretprobe_event(struct trace_iterator *iter, int flags,
1474 struct trace_event *event)
1475 {
1476 struct kretprobe_trace_entry_head *field;
1477 struct trace_seq *s = &iter->seq;
1478 struct trace_probe *tp;
1479 u8 *data;
1480 int i;
1481
1482 field = (struct kretprobe_trace_entry_head *)iter->ent;
1483 tp = container_of(event, struct trace_probe, call.event);
1484
1485 if (!trace_seq_printf(s, "%s: (", tp->call.name))
1486 goto partial;
1487
1488 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1489 goto partial;
1490
1491 if (!trace_seq_puts(s, " <- "))
1492 goto partial;
1493
1494 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1495 goto partial;
1496
1497 if (!trace_seq_puts(s, ")"))
1498 goto partial;
1499
1500 data = (u8 *)&field[1];
1501 for (i = 0; i < tp->nr_args; i++)
1502 if (!tp->args[i].type->print(s, tp->args[i].name,
1503 data + tp->args[i].offset, field))
1504 goto partial;
1505
1506 if (!trace_seq_puts(s, "\n"))
1507 goto partial;
1508
1509 return TRACE_TYPE_HANDLED;
1510 partial:
1511 return TRACE_TYPE_PARTIAL_LINE;
1512 }
1513
1514 static int probe_event_enable(struct ftrace_event_call *call)
1515 {
1516 struct trace_probe *tp = (struct trace_probe *)call->data;
1517
1518 tp->flags |= TP_FLAG_TRACE;
1519 if (probe_is_return(tp))
1520 return enable_kretprobe(&tp->rp);
1521 else
1522 return enable_kprobe(&tp->rp.kp);
1523 }
1524
1525 static void probe_event_disable(struct ftrace_event_call *call)
1526 {
1527 struct trace_probe *tp = (struct trace_probe *)call->data;
1528
1529 tp->flags &= ~TP_FLAG_TRACE;
1530 if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
1531 if (probe_is_return(tp))
1532 disable_kretprobe(&tp->rp);
1533 else
1534 disable_kprobe(&tp->rp.kp);
1535 }
1536 }
1537
1538 #undef DEFINE_FIELD
1539 #define DEFINE_FIELD(type, item, name, is_signed) \
1540 do { \
1541 ret = trace_define_field(event_call, #type, name, \
1542 offsetof(typeof(field), item), \
1543 sizeof(field.item), is_signed, \
1544 FILTER_OTHER); \
1545 if (ret) \
1546 return ret; \
1547 } while (0)
1548
1549 static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1550 {
1551 int ret, i;
1552 struct kprobe_trace_entry_head field;
1553 struct trace_probe *tp = (struct trace_probe *)event_call->data;
1554
1555 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1556 /* Set argument names as fields */
1557 for (i = 0; i < tp->nr_args; i++) {
1558 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1559 tp->args[i].name,
1560 sizeof(field) + tp->args[i].offset,
1561 tp->args[i].type->size,
1562 tp->args[i].type->is_signed,
1563 FILTER_OTHER);
1564 if (ret)
1565 return ret;
1566 }
1567 return 0;
1568 }
1569
1570 static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1571 {
1572 int ret, i;
1573 struct kretprobe_trace_entry_head field;
1574 struct trace_probe *tp = (struct trace_probe *)event_call->data;
1575
1576 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1577 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1578 /* Set argument names as fields */
1579 for (i = 0; i < tp->nr_args; i++) {
1580 ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1581 tp->args[i].name,
1582 sizeof(field) + tp->args[i].offset,
1583 tp->args[i].type->size,
1584 tp->args[i].type->is_signed,
1585 FILTER_OTHER);
1586 if (ret)
1587 return ret;
1588 }
1589 return 0;
1590 }
1591
1592 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
1593 {
1594 int i;
1595 int pos = 0;
1596
1597 const char *fmt, *arg;
1598
1599 if (!probe_is_return(tp)) {
1600 fmt = "(%lx)";
1601 arg = "REC->" FIELD_STRING_IP;
1602 } else {
1603 fmt = "(%lx <- %lx)";
1604 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1605 }
1606
1607 /* When len=0, we just calculate the needed length */
1608 #define LEN_OR_ZERO (len ? len - pos : 0)
1609
1610 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1611
1612 for (i = 0; i < tp->nr_args; i++) {
1613 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
1614 tp->args[i].name, tp->args[i].type->fmt);
1615 }
1616
1617 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
1618
1619 for (i = 0; i < tp->nr_args; i++) {
1620 if (strcmp(tp->args[i].type->name, "string") == 0)
1621 pos += snprintf(buf + pos, LEN_OR_ZERO,
1622 ", __get_str(%s)",
1623 tp->args[i].name);
1624 else
1625 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
1626 tp->args[i].name);
1627 }
1628
1629 #undef LEN_OR_ZERO
1630
1631 /* return the length of print_fmt */
1632 return pos;
1633 }
1634
1635 static int set_print_fmt(struct trace_probe *tp)
1636 {
1637 int len;
1638 char *print_fmt;
1639
1640 /* First: called with 0 length to calculate the needed length */
1641 len = __set_print_fmt(tp, NULL, 0);
1642 print_fmt = kmalloc(len + 1, GFP_KERNEL);
1643 if (!print_fmt)
1644 return -ENOMEM;
1645
1646 /* Second: actually write the @print_fmt */
1647 __set_print_fmt(tp, print_fmt, len + 1);
1648 tp->call.print_fmt = print_fmt;
1649
1650 return 0;
1651 }
1652
1653 #ifdef CONFIG_PERF_EVENTS
1654
1655 /* Kprobe profile handler */
1656 static __kprobes void kprobe_perf_func(struct kprobe *kp,
1657 struct pt_regs *regs)
1658 {
1659 struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1660 struct ftrace_event_call *call = &tp->call;
1661 struct kprobe_trace_entry_head *entry;
1662 struct hlist_head *head;
1663 int size, __size, dsize;
1664 int rctx;
1665
1666 dsize = __get_data_size(tp, regs);
1667 __size = sizeof(*entry) + tp->size + dsize;
1668 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1669 size -= sizeof(u32);
1670 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1671 "profile buffer not large enough"))
1672 return;
1673
1674 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1675 if (!entry)
1676 return;
1677
1678 entry->ip = (unsigned long)kp->addr;
1679 memset(&entry[1], 0, dsize);
1680 store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1681
1682 head = this_cpu_ptr(call->perf_events);
1683 perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
1684 }
1685
1686 /* Kretprobe profile handler */
1687 static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
1688 struct pt_regs *regs)
1689 {
1690 struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1691 struct ftrace_event_call *call = &tp->call;
1692 struct kretprobe_trace_entry_head *entry;
1693 struct hlist_head *head;
1694 int size, __size, dsize;
1695 int rctx;
1696
1697 dsize = __get_data_size(tp, regs);
1698 __size = sizeof(*entry) + tp->size + dsize;
1699 size = ALIGN(__size + sizeof(u32), sizeof(u64));
1700 size -= sizeof(u32);
1701 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1702 "profile buffer not large enough"))
1703 return;
1704
1705 entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1706 if (!entry)
1707 return;
1708
1709 entry->func = (unsigned long)tp->rp.kp.addr;
1710 entry->ret_ip = (unsigned long)ri->ret_addr;
1711 store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1712
1713 head = this_cpu_ptr(call->perf_events);
1714 perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
1715 }
1716
1717 static int probe_perf_enable(struct ftrace_event_call *call)
1718 {
1719 struct trace_probe *tp = (struct trace_probe *)call->data;
1720
1721 tp->flags |= TP_FLAG_PROFILE;
1722
1723 if (probe_is_return(tp))
1724 return enable_kretprobe(&tp->rp);
1725 else
1726 return enable_kprobe(&tp->rp.kp);
1727 }
1728
1729 static void probe_perf_disable(struct ftrace_event_call *call)
1730 {
1731 struct trace_probe *tp = (struct trace_probe *)call->data;
1732
1733 tp->flags &= ~TP_FLAG_PROFILE;
1734
1735 if (!(tp->flags & TP_FLAG_TRACE)) {
1736 if (probe_is_return(tp))
1737 disable_kretprobe(&tp->rp);
1738 else
1739 disable_kprobe(&tp->rp.kp);
1740 }
1741 }
1742 #endif /* CONFIG_PERF_EVENTS */
1743
1744 static __kprobes
1745 int kprobe_register(struct ftrace_event_call *event, enum trace_reg type)
1746 {
1747 switch (type) {
1748 case TRACE_REG_REGISTER:
1749 return probe_event_enable(event);
1750 case TRACE_REG_UNREGISTER:
1751 probe_event_disable(event);
1752 return 0;
1753
1754 #ifdef CONFIG_PERF_EVENTS
1755 case TRACE_REG_PERF_REGISTER:
1756 return probe_perf_enable(event);
1757 case TRACE_REG_PERF_UNREGISTER:
1758 probe_perf_disable(event);
1759 return 0;
1760 #endif
1761 }
1762 return 0;
1763 }
1764
1765 static __kprobes
1766 int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1767 {
1768 struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1769
1770 if (tp->flags & TP_FLAG_TRACE)
1771 kprobe_trace_func(kp, regs);
1772 #ifdef CONFIG_PERF_EVENTS
1773 if (tp->flags & TP_FLAG_PROFILE)
1774 kprobe_perf_func(kp, regs);
1775 #endif
1776 return 0; /* We don't tweek kernel, so just return 0 */
1777 }
1778
1779 static __kprobes
1780 int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1781 {
1782 struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1783
1784 if (tp->flags & TP_FLAG_TRACE)
1785 kretprobe_trace_func(ri, regs);
1786 #ifdef CONFIG_PERF_EVENTS
1787 if (tp->flags & TP_FLAG_PROFILE)
1788 kretprobe_perf_func(ri, regs);
1789 #endif
1790 return 0; /* We don't tweek kernel, so just return 0 */
1791 }
1792
1793 static struct trace_event_functions kretprobe_funcs = {
1794 .trace = print_kretprobe_event
1795 };
1796
1797 static struct trace_event_functions kprobe_funcs = {
1798 .trace = print_kprobe_event
1799 };
1800
1801 static int register_probe_event(struct trace_probe *tp)
1802 {
1803 struct ftrace_event_call *call = &tp->call;
1804 int ret;
1805
1806 /* Initialize ftrace_event_call */
1807 INIT_LIST_HEAD(&call->class->fields);
1808 if (probe_is_return(tp)) {
1809 call->event.funcs = &kretprobe_funcs;
1810 call->class->define_fields = kretprobe_event_define_fields;
1811 } else {
1812 call->event.funcs = &kprobe_funcs;
1813 call->class->define_fields = kprobe_event_define_fields;
1814 }
1815 if (set_print_fmt(tp) < 0)
1816 return -ENOMEM;
1817 ret = register_ftrace_event(&call->event);
1818 if (!ret) {
1819 kfree(call->print_fmt);
1820 return -ENODEV;
1821 }
1822 call->flags = 0;
1823 call->class->reg = kprobe_register;
1824 call->data = tp;
1825 ret = trace_add_event_call(call);
1826 if (ret) {
1827 pr_info("Failed to register kprobe event: %s\n", call->name);
1828 kfree(call->print_fmt);
1829 unregister_ftrace_event(&call->event);
1830 }
1831 return ret;
1832 }
1833
1834 static void unregister_probe_event(struct trace_probe *tp)
1835 {
1836 /* tp->event is unregistered in trace_remove_event_call() */
1837 trace_remove_event_call(&tp->call);
1838 kfree(tp->call.print_fmt);
1839 }
1840
1841 /* Make a debugfs interface for controlling probe points */
1842 static __init int init_kprobe_trace(void)
1843 {
1844 struct dentry *d_tracer;
1845 struct dentry *entry;
1846
1847 d_tracer = tracing_init_dentry();
1848 if (!d_tracer)
1849 return 0;
1850
1851 entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1852 NULL, &kprobe_events_ops);
1853
1854 /* Event list interface */
1855 if (!entry)
1856 pr_warning("Could not create debugfs "
1857 "'kprobe_events' entry\n");
1858
1859 /* Profile interface */
1860 entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1861 NULL, &kprobe_profile_ops);
1862
1863 if (!entry)
1864 pr_warning("Could not create debugfs "
1865 "'kprobe_profile' entry\n");
1866 return 0;
1867 }
1868 fs_initcall(init_kprobe_trace);
1869
1870
1871 #ifdef CONFIG_FTRACE_STARTUP_TEST
1872
1873 static int kprobe_trace_selftest_target(int a1, int a2, int a3,
1874 int a4, int a5, int a6)
1875 {
1876 return a1 + a2 + a3 + a4 + a5 + a6;
1877 }
1878
1879 static __init int kprobe_trace_self_tests_init(void)
1880 {
1881 int ret, warn = 0;
1882 int (*target)(int, int, int, int, int, int);
1883 struct trace_probe *tp;
1884
1885 target = kprobe_trace_selftest_target;
1886
1887 pr_info("Testing kprobe tracing: ");
1888
1889 ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1890 "$stack $stack0 +0($stack)");
1891 if (WARN_ON_ONCE(ret)) {
1892 pr_warning("error on probing function entry.\n");
1893 warn++;
1894 } else {
1895 /* Enable trace point */
1896 tp = find_probe_event("testprobe", KPROBE_EVENT_SYSTEM);
1897 if (WARN_ON_ONCE(tp == NULL)) {
1898 pr_warning("error on getting new probe.\n");
1899 warn++;
1900 } else
1901 probe_event_enable(&tp->call);
1902 }
1903
1904 ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1905 "$retval");
1906 if (WARN_ON_ONCE(ret)) {
1907 pr_warning("error on probing function return.\n");
1908 warn++;
1909 } else {
1910 /* Enable trace point */
1911 tp = find_probe_event("testprobe2", KPROBE_EVENT_SYSTEM);
1912 if (WARN_ON_ONCE(tp == NULL)) {
1913 pr_warning("error on getting new probe.\n");
1914 warn++;
1915 } else
1916 probe_event_enable(&tp->call);
1917 }
1918
1919 if (warn)
1920 goto end;
1921
1922 ret = target(1, 2, 3, 4, 5, 6);
1923
1924 ret = command_trace_probe("-:testprobe");
1925 if (WARN_ON_ONCE(ret)) {
1926 pr_warning("error on deleting a probe.\n");
1927 warn++;
1928 }
1929
1930 ret = command_trace_probe("-:testprobe2");
1931 if (WARN_ON_ONCE(ret)) {
1932 pr_warning("error on deleting a probe.\n");
1933 warn++;
1934 }
1935
1936 end:
1937 cleanup_all_probes();
1938 if (warn)
1939 pr_cont("NG: Some tests are failed. Please check them.\n");
1940 else
1941 pr_cont("OK\n");
1942 return 0;
1943 }
1944
1945 late_initcall(kprobe_trace_self_tests_init);
1946
1947 #endif
Linux kernel - Deliverables
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