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1/*
2 * Common code for probe-based Dynamic events.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
16 *
17 * This code was copied from kernel/trace/trace_kprobe.c written by
18 * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
19 *
20 * Updates to make this generic:
21 * Copyright (C) IBM Corporation, 2010-2011
22 * Author: Srikar Dronamraju
23 */
24
25#include "trace_probe.h"
26
27const char *reserved_field_names[] = {
28 "common_type",
29 "common_flags",
30 "common_preempt_count",
31 "common_pid",
32 "common_tgid",
33 FIELD_STRING_IP,
34 FIELD_STRING_RETIP,
35 FIELD_STRING_FUNC,
36};
37
38/* Printing in basic type function template */
39#define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt) \
40int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name, \
41 void *data, void *ent) \
42{ \
43 trace_seq_printf(s, " %s=" fmt, name, *(type *)data); \
44 return !trace_seq_has_overflowed(s); \
45} \
46const char PRINT_TYPE_FMT_NAME(type)[] = fmt; \
47NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(type));
48
49DEFINE_BASIC_PRINT_TYPE_FUNC(u8 , "0x%x")
50DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "0x%x")
51DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "0x%x")
52DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "0x%Lx")
53DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d")
54DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d")
55DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%d")
56DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%Ld")
57
58/* Print type function for string type */
59int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
60 void *data, void *ent)
61{
62 int len = *(u32 *)data >> 16;
63
64 if (!len)
65 trace_seq_printf(s, " %s=(fault)", name);
66 else
67 trace_seq_printf(s, " %s=\"%s\"", name,
68 (const char *)get_loc_data(data, ent));
69 return !trace_seq_has_overflowed(s);
70}
71NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string));
72
73const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
74
75#define CHECK_FETCH_FUNCS(method, fn) \
76 (((FETCH_FUNC_NAME(method, u8) == fn) || \
77 (FETCH_FUNC_NAME(method, u16) == fn) || \
78 (FETCH_FUNC_NAME(method, u32) == fn) || \
79 (FETCH_FUNC_NAME(method, u64) == fn) || \
80 (FETCH_FUNC_NAME(method, string) == fn) || \
81 (FETCH_FUNC_NAME(method, string_size) == fn)) \
82 && (fn != NULL))
83
84/* Data fetch function templates */
85#define DEFINE_FETCH_reg(type) \
86void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, void *offset, void *dest) \
87{ \
88 *(type *)dest = (type)regs_get_register(regs, \
89 (unsigned int)((unsigned long)offset)); \
90} \
91NOKPROBE_SYMBOL(FETCH_FUNC_NAME(reg, type));
92DEFINE_BASIC_FETCH_FUNCS(reg)
93/* No string on the register */
94#define fetch_reg_string NULL
95#define fetch_reg_string_size NULL
96
97#define DEFINE_FETCH_retval(type) \
98void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs, \
99 void *dummy, void *dest) \
100{ \
101 *(type *)dest = (type)regs_return_value(regs); \
102} \
103NOKPROBE_SYMBOL(FETCH_FUNC_NAME(retval, type));
104DEFINE_BASIC_FETCH_FUNCS(retval)
105/* No string on the retval */
106#define fetch_retval_string NULL
107#define fetch_retval_string_size NULL
108
109/* Dereference memory access function */
110struct deref_fetch_param {
111 struct fetch_param orig;
112 long offset;
113 fetch_func_t fetch;
114 fetch_func_t fetch_size;
115};
116
117#define DEFINE_FETCH_deref(type) \
118void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs, \
119 void *data, void *dest) \
120{ \
121 struct deref_fetch_param *dprm = data; \
122 unsigned long addr; \
123 call_fetch(&dprm->orig, regs, &addr); \
124 if (addr) { \
125 addr += dprm->offset; \
126 dprm->fetch(regs, (void *)addr, dest); \
127 } else \
128 *(type *)dest = 0; \
129} \
130NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, type));
131DEFINE_BASIC_FETCH_FUNCS(deref)
132DEFINE_FETCH_deref(string)
133
134void FETCH_FUNC_NAME(deref, string_size)(struct pt_regs *regs,
135 void *data, void *dest)
136{
137 struct deref_fetch_param *dprm = data;
138 unsigned long addr;
139
140 call_fetch(&dprm->orig, regs, &addr);
141 if (addr && dprm->fetch_size) {
142 addr += dprm->offset;
143 dprm->fetch_size(regs, (void *)addr, dest);
144 } else
145 *(string_size *)dest = 0;
146}
147NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, string_size));
148
149static void update_deref_fetch_param(struct deref_fetch_param *data)
150{
151 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
152 update_deref_fetch_param(data->orig.data);
153 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
154 update_symbol_cache(data->orig.data);
155}
156NOKPROBE_SYMBOL(update_deref_fetch_param);
157
158static void free_deref_fetch_param(struct deref_fetch_param *data)
159{
160 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
161 free_deref_fetch_param(data->orig.data);
162 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
163 free_symbol_cache(data->orig.data);
164 kfree(data);
165}
166NOKPROBE_SYMBOL(free_deref_fetch_param);
167
168/* Bitfield fetch function */
169struct bitfield_fetch_param {
170 struct fetch_param orig;
171 unsigned char hi_shift;
172 unsigned char low_shift;
173};
174
175#define DEFINE_FETCH_bitfield(type) \
176void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs, \
177 void *data, void *dest) \
178{ \
179 struct bitfield_fetch_param *bprm = data; \
180 type buf = 0; \
181 call_fetch(&bprm->orig, regs, &buf); \
182 if (buf) { \
183 buf <<= bprm->hi_shift; \
184 buf >>= bprm->low_shift; \
185 } \
186 *(type *)dest = buf; \
187} \
188NOKPROBE_SYMBOL(FETCH_FUNC_NAME(bitfield, type));
189DEFINE_BASIC_FETCH_FUNCS(bitfield)
190#define fetch_bitfield_string NULL
191#define fetch_bitfield_string_size NULL
192
193static void
194update_bitfield_fetch_param(struct bitfield_fetch_param *data)
195{
196 /*
197 * Don't check the bitfield itself, because this must be the
198 * last fetch function.
199 */
200 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
201 update_deref_fetch_param(data->orig.data);
202 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
203 update_symbol_cache(data->orig.data);
204}
205
206static void
207free_bitfield_fetch_param(struct bitfield_fetch_param *data)
208{
209 /*
210 * Don't check the bitfield itself, because this must be the
211 * last fetch function.
212 */
213 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
214 free_deref_fetch_param(data->orig.data);
215 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
216 free_symbol_cache(data->orig.data);
217
218 kfree(data);
219}
220
221static const struct fetch_type *find_fetch_type(const char *type,
222 const struct fetch_type *ftbl)
223{
224 int i;
225
226 if (!type)
227 type = DEFAULT_FETCH_TYPE_STR;
228
229 /* Special case: bitfield */
230 if (*type == 'b') {
231 unsigned long bs;
232
233 type = strchr(type, '/');
234 if (!type)
235 goto fail;
236
237 type++;
238 if (kstrtoul(type, 0, &bs))
239 goto fail;
240
241 switch (bs) {
242 case 8:
243 return find_fetch_type("u8", ftbl);
244 case 16:
245 return find_fetch_type("u16", ftbl);
246 case 32:
247 return find_fetch_type("u32", ftbl);
248 case 64:
249 return find_fetch_type("u64", ftbl);
250 default:
251 goto fail;
252 }
253 }
254
255 for (i = 0; ftbl[i].name; i++) {
256 if (strcmp(type, ftbl[i].name) == 0)
257 return &ftbl[i];
258 }
259
260fail:
261 return NULL;
262}
263
264/* Special function : only accept unsigned long */
265static void fetch_kernel_stack_address(struct pt_regs *regs, void *dummy, void *dest)
266{
267 *(unsigned long *)dest = kernel_stack_pointer(regs);
268}
269NOKPROBE_SYMBOL(fetch_kernel_stack_address);
270
271static void fetch_user_stack_address(struct pt_regs *regs, void *dummy, void *dest)
272{
273 *(unsigned long *)dest = user_stack_pointer(regs);
274}
275NOKPROBE_SYMBOL(fetch_user_stack_address);
276
277static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
278 fetch_func_t orig_fn,
279 const struct fetch_type *ftbl)
280{
281 int i;
282
283 if (type != &ftbl[FETCH_TYPE_STRING])
284 return NULL; /* Only string type needs size function */
285
286 for (i = 0; i < FETCH_MTD_END; i++)
287 if (type->fetch[i] == orig_fn)
288 return ftbl[FETCH_TYPE_STRSIZE].fetch[i];
289
290 WARN_ON(1); /* This should not happen */
291
292 return NULL;
293}
294
295/* Split symbol and offset. */
296int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
297{
298 char *tmp;
299 int ret;
300
301 if (!offset)
302 return -EINVAL;
303
304 tmp = strchr(symbol, '+');
305 if (tmp) {
306 /* skip sign because kstrtoul doesn't accept '+' */
307 ret = kstrtoul(tmp + 1, 0, offset);
308 if (ret)
309 return ret;
310
311 *tmp = '\0';
312 } else
313 *offset = 0;
314
315 return 0;
316}
317
318#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
319
320static int parse_probe_vars(char *arg, const struct fetch_type *t,
321 struct fetch_param *f, bool is_return,
322 bool is_kprobe)
323{
324 int ret = 0;
325 unsigned long param;
326
327 if (strcmp(arg, "retval") == 0) {
328 if (is_return)
329 f->fn = t->fetch[FETCH_MTD_retval];
330 else
331 ret = -EINVAL;
332 } else if (strncmp(arg, "stack", 5) == 0) {
333 if (arg[5] == '\0') {
334 if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR))
335 return -EINVAL;
336
337 if (is_kprobe)
338 f->fn = fetch_kernel_stack_address;
339 else
340 f->fn = fetch_user_stack_address;
341 } else if (isdigit(arg[5])) {
342 ret = kstrtoul(arg + 5, 10, ¶m);
343 if (ret || (is_kprobe && param > PARAM_MAX_STACK))
344 ret = -EINVAL;
345 else {
346 f->fn = t->fetch[FETCH_MTD_stack];
347 f->data = (void *)param;
348 }
349 } else
350 ret = -EINVAL;
351 } else
352 ret = -EINVAL;
353
354 return ret;
355}
356
357/* Recursive argument parser */
358static int parse_probe_arg(char *arg, const struct fetch_type *t,
359 struct fetch_param *f, bool is_return, bool is_kprobe,
360 const struct fetch_type *ftbl)
361{
362 unsigned long param;
363 long offset;
364 char *tmp;
365 int ret = 0;
366
367 switch (arg[0]) {
368 case '$':
369 ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
370 break;
371
372 case '%': /* named register */
373 ret = regs_query_register_offset(arg + 1);
374 if (ret >= 0) {
375 f->fn = t->fetch[FETCH_MTD_reg];
376 f->data = (void *)(unsigned long)ret;
377 ret = 0;
378 }
379 break;
380
381 case '@': /* memory, file-offset or symbol */
382 if (isdigit(arg[1])) {
383 ret = kstrtoul(arg + 1, 0, ¶m);
384 if (ret)
385 break;
386
387 f->fn = t->fetch[FETCH_MTD_memory];
388 f->data = (void *)param;
389 } else if (arg[1] == '+') {
390 /* kprobes don't support file offsets */
391 if (is_kprobe)
392 return -EINVAL;
393
394 ret = kstrtol(arg + 2, 0, &offset);
395 if (ret)
396 break;
397
398 f->fn = t->fetch[FETCH_MTD_file_offset];
399 f->data = (void *)offset;
400 } else {
401 /* uprobes don't support symbols */
402 if (!is_kprobe)
403 return -EINVAL;
404
405 ret = traceprobe_split_symbol_offset(arg + 1, &offset);
406 if (ret)
407 break;
408
409 f->data = alloc_symbol_cache(arg + 1, offset);
410 if (f->data)
411 f->fn = t->fetch[FETCH_MTD_symbol];
412 }
413 break;
414
415 case '+': /* deref memory */
416 arg++; /* Skip '+', because kstrtol() rejects it. */
417 case '-':
418 tmp = strchr(arg, '(');
419 if (!tmp)
420 break;
421
422 *tmp = '\0';
423 ret = kstrtol(arg, 0, &offset);
424
425 if (ret)
426 break;
427
428 arg = tmp + 1;
429 tmp = strrchr(arg, ')');
430
431 if (tmp) {
432 struct deref_fetch_param *dprm;
433 const struct fetch_type *t2;
434
435 t2 = find_fetch_type(NULL, ftbl);
436 *tmp = '\0';
437 dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL);
438
439 if (!dprm)
440 return -ENOMEM;
441
442 dprm->offset = offset;
443 dprm->fetch = t->fetch[FETCH_MTD_memory];
444 dprm->fetch_size = get_fetch_size_function(t,
445 dprm->fetch, ftbl);
446 ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
447 is_kprobe, ftbl);
448 if (ret)
449 kfree(dprm);
450 else {
451 f->fn = t->fetch[FETCH_MTD_deref];
452 f->data = (void *)dprm;
453 }
454 }
455 break;
456 }
457 if (!ret && !f->fn) { /* Parsed, but do not find fetch method */
458 pr_info("%s type has no corresponding fetch method.\n", t->name);
459 ret = -EINVAL;
460 }
461
462 return ret;
463}
464
465#define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
466
467/* Bitfield type needs to be parsed into a fetch function */
468static int __parse_bitfield_probe_arg(const char *bf,
469 const struct fetch_type *t,
470 struct fetch_param *f)
471{
472 struct bitfield_fetch_param *bprm;
473 unsigned long bw, bo;
474 char *tail;
475
476 if (*bf != 'b')
477 return 0;
478
479 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
480 if (!bprm)
481 return -ENOMEM;
482
483 bprm->orig = *f;
484 f->fn = t->fetch[FETCH_MTD_bitfield];
485 f->data = (void *)bprm;
486 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
487
488 if (bw == 0 || *tail != '@')
489 return -EINVAL;
490
491 bf = tail + 1;
492 bo = simple_strtoul(bf, &tail, 0);
493
494 if (tail == bf || *tail != '/')
495 return -EINVAL;
496
497 bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
498 bprm->low_shift = bprm->hi_shift + bo;
499
500 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
501}
502
503/* String length checking wrapper */
504int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
505 struct probe_arg *parg, bool is_return, bool is_kprobe,
506 const struct fetch_type *ftbl)
507{
508 const char *t;
509 int ret;
510
511 if (strlen(arg) > MAX_ARGSTR_LEN) {
512 pr_info("Argument is too long.: %s\n", arg);
513 return -ENOSPC;
514 }
515 parg->comm = kstrdup(arg, GFP_KERNEL);
516 if (!parg->comm) {
517 pr_info("Failed to allocate memory for command '%s'.\n", arg);
518 return -ENOMEM;
519 }
520 t = strchr(parg->comm, ':');
521 if (t) {
522 arg[t - parg->comm] = '\0';
523 t++;
524 }
525 parg->type = find_fetch_type(t, ftbl);
526 if (!parg->type) {
527 pr_info("Unsupported type: %s\n", t);
528 return -EINVAL;
529 }
530 parg->offset = *size;
531 *size += parg->type->size;
532 ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return,
533 is_kprobe, ftbl);
534
535 if (ret >= 0 && t != NULL)
536 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
537
538 if (ret >= 0) {
539 parg->fetch_size.fn = get_fetch_size_function(parg->type,
540 parg->fetch.fn,
541 ftbl);
542 parg->fetch_size.data = parg->fetch.data;
543 }
544
545 return ret;
546}
547
548/* Return 1 if name is reserved or already used by another argument */
549int traceprobe_conflict_field_name(const char *name,
550 struct probe_arg *args, int narg)
551{
552 int i;
553
554 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
555 if (strcmp(reserved_field_names[i], name) == 0)
556 return 1;
557
558 for (i = 0; i < narg; i++)
559 if (strcmp(args[i].name, name) == 0)
560 return 1;
561
562 return 0;
563}
564
565void traceprobe_update_arg(struct probe_arg *arg)
566{
567 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
568 update_bitfield_fetch_param(arg->fetch.data);
569 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
570 update_deref_fetch_param(arg->fetch.data);
571 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
572 update_symbol_cache(arg->fetch.data);
573}
574
575void traceprobe_free_probe_arg(struct probe_arg *arg)
576{
577 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
578 free_bitfield_fetch_param(arg->fetch.data);
579 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
580 free_deref_fetch_param(arg->fetch.data);
581 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
582 free_symbol_cache(arg->fetch.data);
583
584 kfree(arg->name);
585 kfree(arg->comm);
586}
587
588int traceprobe_command(const char *buf, int (*createfn)(int, char **))
589{
590 char **argv;
591 int argc, ret;
592
593 argc = 0;
594 ret = 0;
595 argv = argv_split(GFP_KERNEL, buf, &argc);
596 if (!argv)
597 return -ENOMEM;
598
599 if (argc)
600 ret = createfn(argc, argv);
601
602 argv_free(argv);
603
604 return ret;
605}
606
607#define WRITE_BUFSIZE 4096
608
609ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
610 size_t count, loff_t *ppos,
611 int (*createfn)(int, char **))
612{
613 char *kbuf, *tmp;
614 int ret = 0;
615 size_t done = 0;
616 size_t size;
617
618 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
619 if (!kbuf)
620 return -ENOMEM;
621
622 while (done < count) {
623 size = count - done;
624
625 if (size >= WRITE_BUFSIZE)
626 size = WRITE_BUFSIZE - 1;
627
628 if (copy_from_user(kbuf, buffer + done, size)) {
629 ret = -EFAULT;
630 goto out;
631 }
632 kbuf[size] = '\0';
633 tmp = strchr(kbuf, '\n');
634
635 if (tmp) {
636 *tmp = '\0';
637 size = tmp - kbuf + 1;
638 } else if (done + size < count) {
639 pr_warn("Line length is too long: Should be less than %d\n",
640 WRITE_BUFSIZE);
641 ret = -EINVAL;
642 goto out;
643 }
644 done += size;
645 /* Remove comments */
646 tmp = strchr(kbuf, '#');
647
648 if (tmp)
649 *tmp = '\0';
650
651 ret = traceprobe_command(kbuf, createfn);
652 if (ret)
653 goto out;
654 }
655 ret = done;
656
657out:
658 kfree(kbuf);
659
660 return ret;
661}
662
663static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
664 bool is_return)
665{
666 int i;
667 int pos = 0;
668
669 const char *fmt, *arg;
670
671 if (!is_return) {
672 fmt = "(%lx)";
673 arg = "REC->" FIELD_STRING_IP;
674 } else {
675 fmt = "(%lx <- %lx)";
676 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
677 }
678
679 /* When len=0, we just calculate the needed length */
680#define LEN_OR_ZERO (len ? len - pos : 0)
681
682 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
683
684 for (i = 0; i < tp->nr_args; i++) {
685 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
686 tp->args[i].name, tp->args[i].type->fmt);
687 }
688
689 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
690
691 for (i = 0; i < tp->nr_args; i++) {
692 if (strcmp(tp->args[i].type->name, "string") == 0)
693 pos += snprintf(buf + pos, LEN_OR_ZERO,
694 ", __get_str(%s)",
695 tp->args[i].name);
696 else
697 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
698 tp->args[i].name);
699 }
700
701#undef LEN_OR_ZERO
702
703 /* return the length of print_fmt */
704 return pos;
705}
706
707int set_print_fmt(struct trace_probe *tp, bool is_return)
708{
709 int len;
710 char *print_fmt;
711
712 /* First: called with 0 length to calculate the needed length */
713 len = __set_print_fmt(tp, NULL, 0, is_return);
714 print_fmt = kmalloc(len + 1, GFP_KERNEL);
715 if (!print_fmt)
716 return -ENOMEM;
717
718 /* Second: actually write the @print_fmt */
719 __set_print_fmt(tp, print_fmt, len + 1, is_return);
720 tp->call.print_fmt = print_fmt;
721
722 return 0;
723}
1/*
2 * Common code for probe-based Dynamic events.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
16 *
17 * This code was copied from kernel/trace/trace_kprobe.c written by
18 * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
19 *
20 * Updates to make this generic:
21 * Copyright (C) IBM Corporation, 2010-2011
22 * Author: Srikar Dronamraju
23 */
24#define pr_fmt(fmt) "trace_probe: " fmt
25
26#include "trace_probe.h"
27
28const char *reserved_field_names[] = {
29 "common_type",
30 "common_flags",
31 "common_preempt_count",
32 "common_pid",
33 "common_tgid",
34 FIELD_STRING_IP,
35 FIELD_STRING_RETIP,
36 FIELD_STRING_FUNC,
37};
38
39/* Printing in basic type function template */
40#define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \
41int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, const char *name, \
42 void *data, void *ent) \
43{ \
44 trace_seq_printf(s, " %s=" fmt, name, *(type *)data); \
45 return !trace_seq_has_overflowed(s); \
46} \
47const char PRINT_TYPE_FMT_NAME(tname)[] = fmt; \
48NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(tname));
49
50DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u")
51DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
52DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
53DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
54DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d")
55DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
56DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
57DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
58DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x")
59DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
60DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
61DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
62
63/* Print type function for string type */
64int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
65 void *data, void *ent)
66{
67 int len = *(u32 *)data >> 16;
68
69 if (!len)
70 trace_seq_printf(s, " %s=(fault)", name);
71 else
72 trace_seq_printf(s, " %s=\"%s\"", name,
73 (const char *)get_loc_data(data, ent));
74 return !trace_seq_has_overflowed(s);
75}
76NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string));
77
78const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
79
80#define CHECK_FETCH_FUNCS(method, fn) \
81 (((FETCH_FUNC_NAME(method, u8) == fn) || \
82 (FETCH_FUNC_NAME(method, u16) == fn) || \
83 (FETCH_FUNC_NAME(method, u32) == fn) || \
84 (FETCH_FUNC_NAME(method, u64) == fn) || \
85 (FETCH_FUNC_NAME(method, string) == fn) || \
86 (FETCH_FUNC_NAME(method, string_size) == fn)) \
87 && (fn != NULL))
88
89/* Data fetch function templates */
90#define DEFINE_FETCH_reg(type) \
91void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, void *offset, void *dest) \
92{ \
93 *(type *)dest = (type)regs_get_register(regs, \
94 (unsigned int)((unsigned long)offset)); \
95} \
96NOKPROBE_SYMBOL(FETCH_FUNC_NAME(reg, type));
97DEFINE_BASIC_FETCH_FUNCS(reg)
98/* No string on the register */
99#define fetch_reg_string NULL
100#define fetch_reg_string_size NULL
101
102#define DEFINE_FETCH_retval(type) \
103void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs, \
104 void *dummy, void *dest) \
105{ \
106 *(type *)dest = (type)regs_return_value(regs); \
107} \
108NOKPROBE_SYMBOL(FETCH_FUNC_NAME(retval, type));
109DEFINE_BASIC_FETCH_FUNCS(retval)
110/* No string on the retval */
111#define fetch_retval_string NULL
112#define fetch_retval_string_size NULL
113
114/* Dereference memory access function */
115struct deref_fetch_param {
116 struct fetch_param orig;
117 long offset;
118 fetch_func_t fetch;
119 fetch_func_t fetch_size;
120};
121
122#define DEFINE_FETCH_deref(type) \
123void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs, \
124 void *data, void *dest) \
125{ \
126 struct deref_fetch_param *dprm = data; \
127 unsigned long addr; \
128 call_fetch(&dprm->orig, regs, &addr); \
129 if (addr) { \
130 addr += dprm->offset; \
131 dprm->fetch(regs, (void *)addr, dest); \
132 } else \
133 *(type *)dest = 0; \
134} \
135NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, type));
136DEFINE_BASIC_FETCH_FUNCS(deref)
137DEFINE_FETCH_deref(string)
138
139void FETCH_FUNC_NAME(deref, string_size)(struct pt_regs *regs,
140 void *data, void *dest)
141{
142 struct deref_fetch_param *dprm = data;
143 unsigned long addr;
144
145 call_fetch(&dprm->orig, regs, &addr);
146 if (addr && dprm->fetch_size) {
147 addr += dprm->offset;
148 dprm->fetch_size(regs, (void *)addr, dest);
149 } else
150 *(string_size *)dest = 0;
151}
152NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, string_size));
153
154static void update_deref_fetch_param(struct deref_fetch_param *data)
155{
156 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
157 update_deref_fetch_param(data->orig.data);
158 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
159 update_symbol_cache(data->orig.data);
160}
161NOKPROBE_SYMBOL(update_deref_fetch_param);
162
163static void free_deref_fetch_param(struct deref_fetch_param *data)
164{
165 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
166 free_deref_fetch_param(data->orig.data);
167 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
168 free_symbol_cache(data->orig.data);
169 kfree(data);
170}
171NOKPROBE_SYMBOL(free_deref_fetch_param);
172
173/* Bitfield fetch function */
174struct bitfield_fetch_param {
175 struct fetch_param orig;
176 unsigned char hi_shift;
177 unsigned char low_shift;
178};
179
180#define DEFINE_FETCH_bitfield(type) \
181void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs, \
182 void *data, void *dest) \
183{ \
184 struct bitfield_fetch_param *bprm = data; \
185 type buf = 0; \
186 call_fetch(&bprm->orig, regs, &buf); \
187 if (buf) { \
188 buf <<= bprm->hi_shift; \
189 buf >>= bprm->low_shift; \
190 } \
191 *(type *)dest = buf; \
192} \
193NOKPROBE_SYMBOL(FETCH_FUNC_NAME(bitfield, type));
194DEFINE_BASIC_FETCH_FUNCS(bitfield)
195#define fetch_bitfield_string NULL
196#define fetch_bitfield_string_size NULL
197
198static void
199update_bitfield_fetch_param(struct bitfield_fetch_param *data)
200{
201 /*
202 * Don't check the bitfield itself, because this must be the
203 * last fetch function.
204 */
205 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
206 update_deref_fetch_param(data->orig.data);
207 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
208 update_symbol_cache(data->orig.data);
209}
210
211static void
212free_bitfield_fetch_param(struct bitfield_fetch_param *data)
213{
214 /*
215 * Don't check the bitfield itself, because this must be the
216 * last fetch function.
217 */
218 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
219 free_deref_fetch_param(data->orig.data);
220 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
221 free_symbol_cache(data->orig.data);
222
223 kfree(data);
224}
225
226void FETCH_FUNC_NAME(comm, string)(struct pt_regs *regs,
227 void *data, void *dest)
228{
229 int maxlen = get_rloc_len(*(u32 *)dest);
230 u8 *dst = get_rloc_data(dest);
231 long ret;
232
233 if (!maxlen)
234 return;
235
236 ret = strlcpy(dst, current->comm, maxlen);
237 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
238}
239NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string));
240
241void FETCH_FUNC_NAME(comm, string_size)(struct pt_regs *regs,
242 void *data, void *dest)
243{
244 *(u32 *)dest = strlen(current->comm) + 1;
245}
246NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string_size));
247
248static const struct fetch_type *find_fetch_type(const char *type,
249 const struct fetch_type *ftbl)
250{
251 int i;
252
253 if (!type)
254 type = DEFAULT_FETCH_TYPE_STR;
255
256 /* Special case: bitfield */
257 if (*type == 'b') {
258 unsigned long bs;
259
260 type = strchr(type, '/');
261 if (!type)
262 goto fail;
263
264 type++;
265 if (kstrtoul(type, 0, &bs))
266 goto fail;
267
268 switch (bs) {
269 case 8:
270 return find_fetch_type("u8", ftbl);
271 case 16:
272 return find_fetch_type("u16", ftbl);
273 case 32:
274 return find_fetch_type("u32", ftbl);
275 case 64:
276 return find_fetch_type("u64", ftbl);
277 default:
278 goto fail;
279 }
280 }
281
282 for (i = 0; ftbl[i].name; i++) {
283 if (strcmp(type, ftbl[i].name) == 0)
284 return &ftbl[i];
285 }
286
287fail:
288 return NULL;
289}
290
291/* Special function : only accept unsigned long */
292static void fetch_kernel_stack_address(struct pt_regs *regs, void *dummy, void *dest)
293{
294 *(unsigned long *)dest = kernel_stack_pointer(regs);
295}
296NOKPROBE_SYMBOL(fetch_kernel_stack_address);
297
298static void fetch_user_stack_address(struct pt_regs *regs, void *dummy, void *dest)
299{
300 *(unsigned long *)dest = user_stack_pointer(regs);
301}
302NOKPROBE_SYMBOL(fetch_user_stack_address);
303
304static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
305 fetch_func_t orig_fn,
306 const struct fetch_type *ftbl)
307{
308 int i;
309
310 if (type != &ftbl[FETCH_TYPE_STRING])
311 return NULL; /* Only string type needs size function */
312
313 for (i = 0; i < FETCH_MTD_END; i++)
314 if (type->fetch[i] == orig_fn)
315 return ftbl[FETCH_TYPE_STRSIZE].fetch[i];
316
317 WARN_ON(1); /* This should not happen */
318
319 return NULL;
320}
321
322/* Split symbol and offset. */
323int traceprobe_split_symbol_offset(char *symbol, long *offset)
324{
325 char *tmp;
326 int ret;
327
328 if (!offset)
329 return -EINVAL;
330
331 tmp = strpbrk(symbol, "+-");
332 if (tmp) {
333 ret = kstrtol(tmp, 0, offset);
334 if (ret)
335 return ret;
336 *tmp = '\0';
337 } else
338 *offset = 0;
339
340 return 0;
341}
342
343#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
344
345static int parse_probe_vars(char *arg, const struct fetch_type *t,
346 struct fetch_param *f, bool is_return,
347 bool is_kprobe)
348{
349 int ret = 0;
350 unsigned long param;
351
352 if (strcmp(arg, "retval") == 0) {
353 if (is_return)
354 f->fn = t->fetch[FETCH_MTD_retval];
355 else
356 ret = -EINVAL;
357 } else if (strncmp(arg, "stack", 5) == 0) {
358 if (arg[5] == '\0') {
359 if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR))
360 return -EINVAL;
361
362 if (is_kprobe)
363 f->fn = fetch_kernel_stack_address;
364 else
365 f->fn = fetch_user_stack_address;
366 } else if (isdigit(arg[5])) {
367 ret = kstrtoul(arg + 5, 10, ¶m);
368 if (ret || (is_kprobe && param > PARAM_MAX_STACK))
369 ret = -EINVAL;
370 else {
371 f->fn = t->fetch[FETCH_MTD_stack];
372 f->data = (void *)param;
373 }
374 } else
375 ret = -EINVAL;
376 } else if (strcmp(arg, "comm") == 0) {
377 if (strcmp(t->name, "string") != 0 &&
378 strcmp(t->name, "string_size") != 0)
379 return -EINVAL;
380 f->fn = t->fetch[FETCH_MTD_comm];
381 } else
382 ret = -EINVAL;
383
384 return ret;
385}
386
387/* Recursive argument parser */
388static int parse_probe_arg(char *arg, const struct fetch_type *t,
389 struct fetch_param *f, bool is_return, bool is_kprobe,
390 const struct fetch_type *ftbl)
391{
392 unsigned long param;
393 long offset;
394 char *tmp;
395 int ret = 0;
396
397 switch (arg[0]) {
398 case '$':
399 ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
400 break;
401
402 case '%': /* named register */
403 ret = regs_query_register_offset(arg + 1);
404 if (ret >= 0) {
405 f->fn = t->fetch[FETCH_MTD_reg];
406 f->data = (void *)(unsigned long)ret;
407 ret = 0;
408 }
409 break;
410
411 case '@': /* memory, file-offset or symbol */
412 if (isdigit(arg[1])) {
413 ret = kstrtoul(arg + 1, 0, ¶m);
414 if (ret)
415 break;
416
417 f->fn = t->fetch[FETCH_MTD_memory];
418 f->data = (void *)param;
419 } else if (arg[1] == '+') {
420 /* kprobes don't support file offsets */
421 if (is_kprobe)
422 return -EINVAL;
423
424 ret = kstrtol(arg + 2, 0, &offset);
425 if (ret)
426 break;
427
428 f->fn = t->fetch[FETCH_MTD_file_offset];
429 f->data = (void *)offset;
430 } else {
431 /* uprobes don't support symbols */
432 if (!is_kprobe)
433 return -EINVAL;
434
435 ret = traceprobe_split_symbol_offset(arg + 1, &offset);
436 if (ret)
437 break;
438
439 f->data = alloc_symbol_cache(arg + 1, offset);
440 if (f->data)
441 f->fn = t->fetch[FETCH_MTD_symbol];
442 }
443 break;
444
445 case '+': /* deref memory */
446 arg++; /* Skip '+', because kstrtol() rejects it. */
447 case '-':
448 tmp = strchr(arg, '(');
449 if (!tmp)
450 break;
451
452 *tmp = '\0';
453 ret = kstrtol(arg, 0, &offset);
454
455 if (ret)
456 break;
457
458 arg = tmp + 1;
459 tmp = strrchr(arg, ')');
460
461 if (tmp) {
462 struct deref_fetch_param *dprm;
463 const struct fetch_type *t2;
464
465 t2 = find_fetch_type(NULL, ftbl);
466 *tmp = '\0';
467 dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL);
468
469 if (!dprm)
470 return -ENOMEM;
471
472 dprm->offset = offset;
473 dprm->fetch = t->fetch[FETCH_MTD_memory];
474 dprm->fetch_size = get_fetch_size_function(t,
475 dprm->fetch, ftbl);
476 ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
477 is_kprobe, ftbl);
478 if (ret)
479 kfree(dprm);
480 else {
481 f->fn = t->fetch[FETCH_MTD_deref];
482 f->data = (void *)dprm;
483 }
484 }
485 break;
486 }
487 if (!ret && !f->fn) { /* Parsed, but do not find fetch method */
488 pr_info("%s type has no corresponding fetch method.\n", t->name);
489 ret = -EINVAL;
490 }
491
492 return ret;
493}
494
495#define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
496
497/* Bitfield type needs to be parsed into a fetch function */
498static int __parse_bitfield_probe_arg(const char *bf,
499 const struct fetch_type *t,
500 struct fetch_param *f)
501{
502 struct bitfield_fetch_param *bprm;
503 unsigned long bw, bo;
504 char *tail;
505
506 if (*bf != 'b')
507 return 0;
508
509 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
510 if (!bprm)
511 return -ENOMEM;
512
513 bprm->orig = *f;
514 f->fn = t->fetch[FETCH_MTD_bitfield];
515 f->data = (void *)bprm;
516 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
517
518 if (bw == 0 || *tail != '@')
519 return -EINVAL;
520
521 bf = tail + 1;
522 bo = simple_strtoul(bf, &tail, 0);
523
524 if (tail == bf || *tail != '/')
525 return -EINVAL;
526
527 bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
528 bprm->low_shift = bprm->hi_shift + bo;
529
530 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
531}
532
533/* String length checking wrapper */
534int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
535 struct probe_arg *parg, bool is_return, bool is_kprobe,
536 const struct fetch_type *ftbl)
537{
538 const char *t;
539 int ret;
540
541 if (strlen(arg) > MAX_ARGSTR_LEN) {
542 pr_info("Argument is too long.: %s\n", arg);
543 return -ENOSPC;
544 }
545 parg->comm = kstrdup(arg, GFP_KERNEL);
546 if (!parg->comm) {
547 pr_info("Failed to allocate memory for command '%s'.\n", arg);
548 return -ENOMEM;
549 }
550 t = strchr(parg->comm, ':');
551 if (t) {
552 arg[t - parg->comm] = '\0';
553 t++;
554 }
555 /*
556 * The default type of $comm should be "string", and it can't be
557 * dereferenced.
558 */
559 if (!t && strcmp(arg, "$comm") == 0)
560 t = "string";
561 parg->type = find_fetch_type(t, ftbl);
562 if (!parg->type) {
563 pr_info("Unsupported type: %s\n", t);
564 return -EINVAL;
565 }
566 parg->offset = *size;
567 *size += parg->type->size;
568 ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return,
569 is_kprobe, ftbl);
570
571 if (ret >= 0 && t != NULL)
572 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
573
574 if (ret >= 0) {
575 parg->fetch_size.fn = get_fetch_size_function(parg->type,
576 parg->fetch.fn,
577 ftbl);
578 parg->fetch_size.data = parg->fetch.data;
579 }
580
581 return ret;
582}
583
584/* Return 1 if name is reserved or already used by another argument */
585int traceprobe_conflict_field_name(const char *name,
586 struct probe_arg *args, int narg)
587{
588 int i;
589
590 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
591 if (strcmp(reserved_field_names[i], name) == 0)
592 return 1;
593
594 for (i = 0; i < narg; i++)
595 if (strcmp(args[i].name, name) == 0)
596 return 1;
597
598 return 0;
599}
600
601void traceprobe_update_arg(struct probe_arg *arg)
602{
603 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
604 update_bitfield_fetch_param(arg->fetch.data);
605 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
606 update_deref_fetch_param(arg->fetch.data);
607 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
608 update_symbol_cache(arg->fetch.data);
609}
610
611void traceprobe_free_probe_arg(struct probe_arg *arg)
612{
613 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
614 free_bitfield_fetch_param(arg->fetch.data);
615 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
616 free_deref_fetch_param(arg->fetch.data);
617 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
618 free_symbol_cache(arg->fetch.data);
619
620 kfree(arg->name);
621 kfree(arg->comm);
622}
623
624static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
625 bool is_return)
626{
627 int i;
628 int pos = 0;
629
630 const char *fmt, *arg;
631
632 if (!is_return) {
633 fmt = "(%lx)";
634 arg = "REC->" FIELD_STRING_IP;
635 } else {
636 fmt = "(%lx <- %lx)";
637 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
638 }
639
640 /* When len=0, we just calculate the needed length */
641#define LEN_OR_ZERO (len ? len - pos : 0)
642
643 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
644
645 for (i = 0; i < tp->nr_args; i++) {
646 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
647 tp->args[i].name, tp->args[i].type->fmt);
648 }
649
650 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
651
652 for (i = 0; i < tp->nr_args; i++) {
653 if (strcmp(tp->args[i].type->name, "string") == 0)
654 pos += snprintf(buf + pos, LEN_OR_ZERO,
655 ", __get_str(%s)",
656 tp->args[i].name);
657 else
658 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
659 tp->args[i].name);
660 }
661
662#undef LEN_OR_ZERO
663
664 /* return the length of print_fmt */
665 return pos;
666}
667
668int set_print_fmt(struct trace_probe *tp, bool is_return)
669{
670 int len;
671 char *print_fmt;
672
673 /* First: called with 0 length to calculate the needed length */
674 len = __set_print_fmt(tp, NULL, 0, is_return);
675 print_fmt = kmalloc(len + 1, GFP_KERNEL);
676 if (!print_fmt)
677 return -ENOMEM;
678
679 /* Second: actually write the @print_fmt */
680 __set_print_fmt(tp, print_fmt, len + 1, is_return);
681 tp->call.print_fmt = print_fmt;
682
683 return 0;
684}