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