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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * Common code for probe-based Dynamic events.
4 *
5 * This code was copied from kernel/trace/trace_kprobe.c written by
6 * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
7 *
8 * Updates to make this generic:
9 * Copyright (C) IBM Corporation, 2010-2011
10 * Author: Srikar Dronamraju
11 */
12#define pr_fmt(fmt) "trace_probe: " fmt
13
14#include <linux/bpf.h>
15#include "trace_btf.h"
16
17#include "trace_probe.h"
18
19#undef C
20#define C(a, b) b
21
22static const char *trace_probe_err_text[] = { ERRORS };
23
24static const char *reserved_field_names[] = {
25 "common_type",
26 "common_flags",
27 "common_preempt_count",
28 "common_pid",
29 "common_tgid",
30 FIELD_STRING_IP,
31 FIELD_STRING_RETIP,
32 FIELD_STRING_FUNC,
33};
34
35/* Printing in basic type function template */
36#define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \
37int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
38{ \
39 trace_seq_printf(s, fmt, *(type *)data); \
40 return !trace_seq_has_overflowed(s); \
41} \
42const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
43
44DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u")
45DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
46DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
47DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
48DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d")
49DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
50DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
51DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
52DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x")
53DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
54DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
55DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
56DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
57
58int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
59{
60 trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
61 return !trace_seq_has_overflowed(s);
62}
63const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
64
65/* Print type function for string type */
66int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
67{
68 int len = *(u32 *)data >> 16;
69
70 if (!len)
71 trace_seq_puts(s, FAULT_STRING);
72 else
73 trace_seq_printf(s, "\"%s\"",
74 (const char *)get_loc_data(data, ent));
75 return !trace_seq_has_overflowed(s);
76}
77
78const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
79
80/* Fetch type information table */
81static const struct fetch_type probe_fetch_types[] = {
82 /* Special types */
83 __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1,
84 "__data_loc char[]"),
85 __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
86 "__data_loc char[]"),
87 __ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1,
88 "__data_loc char[]"),
89 /* Basic types */
90 ASSIGN_FETCH_TYPE(u8, u8, 0),
91 ASSIGN_FETCH_TYPE(u16, u16, 0),
92 ASSIGN_FETCH_TYPE(u32, u32, 0),
93 ASSIGN_FETCH_TYPE(u64, u64, 0),
94 ASSIGN_FETCH_TYPE(s8, u8, 1),
95 ASSIGN_FETCH_TYPE(s16, u16, 1),
96 ASSIGN_FETCH_TYPE(s32, u32, 1),
97 ASSIGN_FETCH_TYPE(s64, u64, 1),
98 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
99 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
100 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
101 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
102 ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8, 0),
103 ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
104
105 ASSIGN_FETCH_TYPE_END
106};
107
108static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
109{
110 int i;
111
112 /* Reject the symbol/symstr for uprobes */
113 if (type && (flags & TPARG_FL_USER) &&
114 (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
115 return NULL;
116
117 if (!type)
118 type = DEFAULT_FETCH_TYPE_STR;
119
120 /* Special case: bitfield */
121 if (*type == 'b') {
122 unsigned long bs;
123
124 type = strchr(type, '/');
125 if (!type)
126 goto fail;
127
128 type++;
129 if (kstrtoul(type, 0, &bs))
130 goto fail;
131
132 switch (bs) {
133 case 8:
134 return find_fetch_type("u8", flags);
135 case 16:
136 return find_fetch_type("u16", flags);
137 case 32:
138 return find_fetch_type("u32", flags);
139 case 64:
140 return find_fetch_type("u64", flags);
141 default:
142 goto fail;
143 }
144 }
145
146 for (i = 0; probe_fetch_types[i].name; i++) {
147 if (strcmp(type, probe_fetch_types[i].name) == 0)
148 return &probe_fetch_types[i];
149 }
150
151fail:
152 return NULL;
153}
154
155static struct trace_probe_log trace_probe_log;
156
157void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
158{
159 trace_probe_log.subsystem = subsystem;
160 trace_probe_log.argc = argc;
161 trace_probe_log.argv = argv;
162 trace_probe_log.index = 0;
163}
164
165void trace_probe_log_clear(void)
166{
167 memset(&trace_probe_log, 0, sizeof(trace_probe_log));
168}
169
170void trace_probe_log_set_index(int index)
171{
172 trace_probe_log.index = index;
173}
174
175void __trace_probe_log_err(int offset, int err_type)
176{
177 char *command, *p;
178 int i, len = 0, pos = 0;
179
180 if (!trace_probe_log.argv)
181 return;
182
183 /* Recalculate the length and allocate buffer */
184 for (i = 0; i < trace_probe_log.argc; i++) {
185 if (i == trace_probe_log.index)
186 pos = len;
187 len += strlen(trace_probe_log.argv[i]) + 1;
188 }
189 command = kzalloc(len, GFP_KERNEL);
190 if (!command)
191 return;
192
193 if (trace_probe_log.index >= trace_probe_log.argc) {
194 /**
195 * Set the error position is next to the last arg + space.
196 * Note that len includes the terminal null and the cursor
197 * appears at pos + 1.
198 */
199 pos = len;
200 offset = 0;
201 }
202
203 /* And make a command string from argv array */
204 p = command;
205 for (i = 0; i < trace_probe_log.argc; i++) {
206 len = strlen(trace_probe_log.argv[i]);
207 strcpy(p, trace_probe_log.argv[i]);
208 p[len] = ' ';
209 p += len + 1;
210 }
211 *(p - 1) = '\0';
212
213 tracing_log_err(NULL, trace_probe_log.subsystem, command,
214 trace_probe_err_text, err_type, pos + offset);
215
216 kfree(command);
217}
218
219/* Split symbol and offset. */
220int traceprobe_split_symbol_offset(char *symbol, long *offset)
221{
222 char *tmp;
223 int ret;
224
225 if (!offset)
226 return -EINVAL;
227
228 tmp = strpbrk(symbol, "+-");
229 if (tmp) {
230 ret = kstrtol(tmp, 0, offset);
231 if (ret)
232 return ret;
233 *tmp = '\0';
234 } else
235 *offset = 0;
236
237 return 0;
238}
239
240/* @buf must has MAX_EVENT_NAME_LEN size */
241int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
242 char *buf, int offset)
243{
244 const char *slash, *event = *pevent;
245 int len;
246
247 slash = strchr(event, '/');
248 if (!slash)
249 slash = strchr(event, '.');
250
251 if (slash) {
252 if (slash == event) {
253 trace_probe_log_err(offset, NO_GROUP_NAME);
254 return -EINVAL;
255 }
256 if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
257 trace_probe_log_err(offset, GROUP_TOO_LONG);
258 return -EINVAL;
259 }
260 strscpy(buf, event, slash - event + 1);
261 if (!is_good_system_name(buf)) {
262 trace_probe_log_err(offset, BAD_GROUP_NAME);
263 return -EINVAL;
264 }
265 *pgroup = buf;
266 *pevent = slash + 1;
267 offset += slash - event + 1;
268 event = *pevent;
269 }
270 len = strlen(event);
271 if (len == 0) {
272 if (slash) {
273 *pevent = NULL;
274 return 0;
275 }
276 trace_probe_log_err(offset, NO_EVENT_NAME);
277 return -EINVAL;
278 } else if (len > MAX_EVENT_NAME_LEN) {
279 trace_probe_log_err(offset, EVENT_TOO_LONG);
280 return -EINVAL;
281 }
282 if (!is_good_name(event)) {
283 trace_probe_log_err(offset, BAD_EVENT_NAME);
284 return -EINVAL;
285 }
286 return 0;
287}
288
289static int parse_trace_event_arg(char *arg, struct fetch_insn *code,
290 struct traceprobe_parse_context *ctx)
291{
292 struct ftrace_event_field *field;
293 struct list_head *head;
294
295 head = trace_get_fields(ctx->event);
296 list_for_each_entry(field, head, link) {
297 if (!strcmp(arg, field->name)) {
298 code->op = FETCH_OP_TP_ARG;
299 code->data = field;
300 return 0;
301 }
302 }
303 return -ENOENT;
304}
305
306#ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
307
308static u32 btf_type_int(const struct btf_type *t)
309{
310 return *(u32 *)(t + 1);
311}
312
313static bool btf_type_is_char_ptr(struct btf *btf, const struct btf_type *type)
314{
315 const struct btf_type *real_type;
316 u32 intdata;
317 s32 tid;
318
319 real_type = btf_type_skip_modifiers(btf, type->type, &tid);
320 if (!real_type)
321 return false;
322
323 if (BTF_INFO_KIND(real_type->info) != BTF_KIND_INT)
324 return false;
325
326 intdata = btf_type_int(real_type);
327 return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
328 && BTF_INT_BITS(intdata) == 8;
329}
330
331static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type)
332{
333 const struct btf_type *real_type;
334 const struct btf_array *array;
335 u32 intdata;
336 s32 tid;
337
338 if (BTF_INFO_KIND(type->info) != BTF_KIND_ARRAY)
339 return false;
340
341 array = (const struct btf_array *)(type + 1);
342
343 real_type = btf_type_skip_modifiers(btf, array->type, &tid);
344
345 intdata = btf_type_int(real_type);
346 return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
347 && BTF_INT_BITS(intdata) == 8;
348}
349
350static int check_prepare_btf_string_fetch(char *typename,
351 struct fetch_insn **pcode,
352 struct traceprobe_parse_context *ctx)
353{
354 struct btf *btf = ctx->btf;
355
356 if (!btf || !ctx->last_type)
357 return 0;
358
359 /* char [] does not need any change. */
360 if (btf_type_is_char_array(btf, ctx->last_type))
361 return 0;
362
363 /* char * requires dereference the pointer. */
364 if (btf_type_is_char_ptr(btf, ctx->last_type)) {
365 struct fetch_insn *code = *pcode + 1;
366
367 if (code->op == FETCH_OP_END) {
368 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
369 return -E2BIG;
370 }
371 if (typename[0] == 'u')
372 code->op = FETCH_OP_UDEREF;
373 else
374 code->op = FETCH_OP_DEREF;
375 code->offset = 0;
376 *pcode = code;
377 return 0;
378 }
379 /* Other types are not available for string */
380 trace_probe_log_err(ctx->offset, BAD_TYPE4STR);
381 return -EINVAL;
382}
383
384static const char *fetch_type_from_btf_type(struct btf *btf,
385 const struct btf_type *type,
386 struct traceprobe_parse_context *ctx)
387{
388 u32 intdata;
389
390 /* TODO: const char * could be converted as a string */
391 switch (BTF_INFO_KIND(type->info)) {
392 case BTF_KIND_ENUM:
393 /* enum is "int", so convert to "s32" */
394 return "s32";
395 case BTF_KIND_ENUM64:
396 return "s64";
397 case BTF_KIND_PTR:
398 /* pointer will be converted to "x??" */
399 if (IS_ENABLED(CONFIG_64BIT))
400 return "x64";
401 else
402 return "x32";
403 case BTF_KIND_INT:
404 intdata = btf_type_int(type);
405 if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) {
406 switch (BTF_INT_BITS(intdata)) {
407 case 8:
408 return "s8";
409 case 16:
410 return "s16";
411 case 32:
412 return "s32";
413 case 64:
414 return "s64";
415 }
416 } else { /* unsigned */
417 switch (BTF_INT_BITS(intdata)) {
418 case 8:
419 return "u8";
420 case 16:
421 return "u16";
422 case 32:
423 return "u32";
424 case 64:
425 return "u64";
426 }
427 /* bitfield, size is encoded in the type */
428 ctx->last_bitsize = BTF_INT_BITS(intdata);
429 ctx->last_bitoffs += BTF_INT_OFFSET(intdata);
430 return "u64";
431 }
432 }
433 /* TODO: support other types */
434
435 return NULL;
436}
437
438static int query_btf_context(struct traceprobe_parse_context *ctx)
439{
440 const struct btf_param *param;
441 const struct btf_type *type;
442 struct btf *btf;
443 s32 nr;
444
445 if (ctx->btf)
446 return 0;
447
448 if (!ctx->funcname)
449 return -EINVAL;
450
451 type = btf_find_func_proto(ctx->funcname, &btf);
452 if (!type)
453 return -ENOENT;
454
455 ctx->btf = btf;
456 ctx->proto = type;
457
458 /* ctx->params is optional, since func(void) will not have params. */
459 nr = 0;
460 param = btf_get_func_param(type, &nr);
461 if (!IS_ERR_OR_NULL(param)) {
462 /* Hide the first 'data' argument of tracepoint */
463 if (ctx->flags & TPARG_FL_TPOINT) {
464 nr--;
465 param++;
466 }
467 }
468
469 if (nr > 0) {
470 ctx->nr_params = nr;
471 ctx->params = param;
472 } else {
473 ctx->nr_params = 0;
474 ctx->params = NULL;
475 }
476
477 return 0;
478}
479
480static void clear_btf_context(struct traceprobe_parse_context *ctx)
481{
482 if (ctx->btf) {
483 btf_put(ctx->btf);
484 ctx->btf = NULL;
485 ctx->proto = NULL;
486 ctx->params = NULL;
487 ctx->nr_params = 0;
488 }
489}
490
491/* Return 1 if the field separater is arrow operator ('->') */
492static int split_next_field(char *varname, char **next_field,
493 struct traceprobe_parse_context *ctx)
494{
495 char *field;
496 int ret = 0;
497
498 field = strpbrk(varname, ".-");
499 if (field) {
500 if (field[0] == '-' && field[1] == '>') {
501 field[0] = '\0';
502 field += 2;
503 ret = 1;
504 } else if (field[0] == '.') {
505 field[0] = '\0';
506 field += 1;
507 } else {
508 trace_probe_log_err(ctx->offset + field - varname, BAD_HYPHEN);
509 return -EINVAL;
510 }
511 *next_field = field;
512 }
513
514 return ret;
515}
516
517/*
518 * Parse the field of data structure. The @type must be a pointer type
519 * pointing the target data structure type.
520 */
521static int parse_btf_field(char *fieldname, const struct btf_type *type,
522 struct fetch_insn **pcode, struct fetch_insn *end,
523 struct traceprobe_parse_context *ctx)
524{
525 struct fetch_insn *code = *pcode;
526 const struct btf_member *field;
527 u32 bitoffs, anon_offs;
528 char *next;
529 int is_ptr;
530 s32 tid;
531
532 do {
533 /* Outer loop for solving arrow operator ('->') */
534 if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) {
535 trace_probe_log_err(ctx->offset, NO_PTR_STRCT);
536 return -EINVAL;
537 }
538 /* Convert a struct pointer type to a struct type */
539 type = btf_type_skip_modifiers(ctx->btf, type->type, &tid);
540 if (!type) {
541 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
542 return -EINVAL;
543 }
544
545 bitoffs = 0;
546 do {
547 /* Inner loop for solving dot operator ('.') */
548 next = NULL;
549 is_ptr = split_next_field(fieldname, &next, ctx);
550 if (is_ptr < 0)
551 return is_ptr;
552
553 anon_offs = 0;
554 field = btf_find_struct_member(ctx->btf, type, fieldname,
555 &anon_offs);
556 if (IS_ERR(field)) {
557 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
558 return PTR_ERR(field);
559 }
560 if (!field) {
561 trace_probe_log_err(ctx->offset, NO_BTF_FIELD);
562 return -ENOENT;
563 }
564 /* Add anonymous structure/union offset */
565 bitoffs += anon_offs;
566
567 /* Accumulate the bit-offsets of the dot-connected fields */
568 if (btf_type_kflag(type)) {
569 bitoffs += BTF_MEMBER_BIT_OFFSET(field->offset);
570 ctx->last_bitsize = BTF_MEMBER_BITFIELD_SIZE(field->offset);
571 } else {
572 bitoffs += field->offset;
573 ctx->last_bitsize = 0;
574 }
575
576 type = btf_type_skip_modifiers(ctx->btf, field->type, &tid);
577 if (!type) {
578 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
579 return -EINVAL;
580 }
581
582 ctx->offset += next - fieldname;
583 fieldname = next;
584 } while (!is_ptr && fieldname);
585
586 if (++code == end) {
587 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
588 return -EINVAL;
589 }
590 code->op = FETCH_OP_DEREF; /* TODO: user deref support */
591 code->offset = bitoffs / 8;
592 *pcode = code;
593
594 ctx->last_bitoffs = bitoffs % 8;
595 ctx->last_type = type;
596 } while (fieldname);
597
598 return 0;
599}
600
601static int __store_entry_arg(struct trace_probe *tp, int argnum);
602
603static int parse_btf_arg(char *varname,
604 struct fetch_insn **pcode, struct fetch_insn *end,
605 struct traceprobe_parse_context *ctx)
606{
607 struct fetch_insn *code = *pcode;
608 const struct btf_param *params;
609 const struct btf_type *type;
610 char *field = NULL;
611 int i, is_ptr, ret;
612 u32 tid;
613
614 if (WARN_ON_ONCE(!ctx->funcname))
615 return -EINVAL;
616
617 is_ptr = split_next_field(varname, &field, ctx);
618 if (is_ptr < 0)
619 return is_ptr;
620 if (!is_ptr && field) {
621 /* dot-connected field on an argument is not supported. */
622 trace_probe_log_err(ctx->offset + field - varname,
623 NOSUP_DAT_ARG);
624 return -EOPNOTSUPP;
625 }
626
627 if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) {
628 code->op = FETCH_OP_RETVAL;
629 /* Check whether the function return type is not void */
630 if (query_btf_context(ctx) == 0) {
631 if (ctx->proto->type == 0) {
632 trace_probe_log_err(ctx->offset, NO_RETVAL);
633 return -ENOENT;
634 }
635 tid = ctx->proto->type;
636 goto found;
637 }
638 if (field) {
639 trace_probe_log_err(ctx->offset + field - varname,
640 NO_BTF_ENTRY);
641 return -ENOENT;
642 }
643 return 0;
644 }
645
646 if (!ctx->btf) {
647 ret = query_btf_context(ctx);
648 if (ret < 0 || ctx->nr_params == 0) {
649 trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
650 return PTR_ERR(params);
651 }
652 }
653 params = ctx->params;
654
655 for (i = 0; i < ctx->nr_params; i++) {
656 const char *name = btf_name_by_offset(ctx->btf, params[i].name_off);
657
658 if (name && !strcmp(name, varname)) {
659 if (tparg_is_function_entry(ctx->flags)) {
660 code->op = FETCH_OP_ARG;
661 if (ctx->flags & TPARG_FL_TPOINT)
662 code->param = i + 1;
663 else
664 code->param = i;
665 } else if (tparg_is_function_return(ctx->flags)) {
666 code->op = FETCH_OP_EDATA;
667 ret = __store_entry_arg(ctx->tp, i);
668 if (ret < 0) {
669 /* internal error */
670 return ret;
671 }
672 code->offset = ret;
673 }
674 tid = params[i].type;
675 goto found;
676 }
677 }
678 trace_probe_log_err(ctx->offset, NO_BTFARG);
679 return -ENOENT;
680
681found:
682 type = btf_type_skip_modifiers(ctx->btf, tid, &tid);
683 if (!type) {
684 trace_probe_log_err(ctx->offset, BAD_BTF_TID);
685 return -EINVAL;
686 }
687 /* Initialize the last type information */
688 ctx->last_type = type;
689 ctx->last_bitoffs = 0;
690 ctx->last_bitsize = 0;
691 if (field) {
692 ctx->offset += field - varname;
693 return parse_btf_field(field, type, pcode, end, ctx);
694 }
695 return 0;
696}
697
698static const struct fetch_type *find_fetch_type_from_btf_type(
699 struct traceprobe_parse_context *ctx)
700{
701 struct btf *btf = ctx->btf;
702 const char *typestr = NULL;
703
704 if (btf && ctx->last_type)
705 typestr = fetch_type_from_btf_type(btf, ctx->last_type, ctx);
706
707 return find_fetch_type(typestr, ctx->flags);
708}
709
710static int parse_btf_bitfield(struct fetch_insn **pcode,
711 struct traceprobe_parse_context *ctx)
712{
713 struct fetch_insn *code = *pcode;
714
715 if ((ctx->last_bitsize % 8 == 0) && ctx->last_bitoffs == 0)
716 return 0;
717
718 code++;
719 if (code->op != FETCH_OP_NOP) {
720 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
721 return -EINVAL;
722 }
723 *pcode = code;
724
725 code->op = FETCH_OP_MOD_BF;
726 code->lshift = 64 - (ctx->last_bitsize + ctx->last_bitoffs);
727 code->rshift = 64 - ctx->last_bitsize;
728 code->basesize = 64 / 8;
729 return 0;
730}
731
732#else
733static void clear_btf_context(struct traceprobe_parse_context *ctx)
734{
735 ctx->btf = NULL;
736}
737
738static int query_btf_context(struct traceprobe_parse_context *ctx)
739{
740 return -EOPNOTSUPP;
741}
742
743static int parse_btf_arg(char *varname,
744 struct fetch_insn **pcode, struct fetch_insn *end,
745 struct traceprobe_parse_context *ctx)
746{
747 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
748 return -EOPNOTSUPP;
749}
750
751static int parse_btf_bitfield(struct fetch_insn **pcode,
752 struct traceprobe_parse_context *ctx)
753{
754 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
755 return -EOPNOTSUPP;
756}
757
758#define find_fetch_type_from_btf_type(ctx) \
759 find_fetch_type(NULL, ctx->flags)
760
761static int check_prepare_btf_string_fetch(char *typename,
762 struct fetch_insn **pcode,
763 struct traceprobe_parse_context *ctx)
764{
765 return 0;
766}
767
768#endif
769
770#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
771
772static int __store_entry_arg(struct trace_probe *tp, int argnum)
773{
774 struct probe_entry_arg *earg = tp->entry_arg;
775 bool match = false;
776 int i, offset;
777
778 if (!earg) {
779 earg = kzalloc(sizeof(*tp->entry_arg), GFP_KERNEL);
780 if (!earg)
781 return -ENOMEM;
782 earg->size = 2 * tp->nr_args + 1;
783 earg->code = kcalloc(earg->size, sizeof(struct fetch_insn),
784 GFP_KERNEL);
785 if (!earg->code) {
786 kfree(earg);
787 return -ENOMEM;
788 }
789 /* Fill the code buffer with 'end' to simplify it */
790 for (i = 0; i < earg->size; i++)
791 earg->code[i].op = FETCH_OP_END;
792 tp->entry_arg = earg;
793 }
794
795 offset = 0;
796 for (i = 0; i < earg->size - 1; i++) {
797 switch (earg->code[i].op) {
798 case FETCH_OP_END:
799 earg->code[i].op = FETCH_OP_ARG;
800 earg->code[i].param = argnum;
801 earg->code[i + 1].op = FETCH_OP_ST_EDATA;
802 earg->code[i + 1].offset = offset;
803 return offset;
804 case FETCH_OP_ARG:
805 match = (earg->code[i].param == argnum);
806 break;
807 case FETCH_OP_ST_EDATA:
808 offset = earg->code[i].offset;
809 if (match)
810 return offset;
811 offset += sizeof(unsigned long);
812 break;
813 default:
814 break;
815 }
816 }
817 return -ENOSPC;
818}
819
820int traceprobe_get_entry_data_size(struct trace_probe *tp)
821{
822 struct probe_entry_arg *earg = tp->entry_arg;
823 int i, size = 0;
824
825 if (!earg)
826 return 0;
827
828 for (i = 0; i < earg->size; i++) {
829 switch (earg->code[i].op) {
830 case FETCH_OP_END:
831 goto out;
832 case FETCH_OP_ST_EDATA:
833 size = earg->code[i].offset + sizeof(unsigned long);
834 break;
835 default:
836 break;
837 }
838 }
839out:
840 return size;
841}
842
843void store_trace_entry_data(void *edata, struct trace_probe *tp, struct pt_regs *regs)
844{
845 struct probe_entry_arg *earg = tp->entry_arg;
846 unsigned long val = 0;
847 int i;
848
849 if (!earg)
850 return;
851
852 for (i = 0; i < earg->size; i++) {
853 struct fetch_insn *code = &earg->code[i];
854
855 switch (code->op) {
856 case FETCH_OP_ARG:
857 val = regs_get_kernel_argument(regs, code->param);
858 break;
859 case FETCH_OP_ST_EDATA:
860 *(unsigned long *)((unsigned long)edata + code->offset) = val;
861 break;
862 case FETCH_OP_END:
863 goto end;
864 default:
865 break;
866 }
867 }
868end:
869 return;
870}
871NOKPROBE_SYMBOL(store_trace_entry_data)
872#endif
873
874#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
875
876/* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */
877static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
878 struct fetch_insn **pcode,
879 struct fetch_insn *end,
880 struct traceprobe_parse_context *ctx)
881{
882 struct fetch_insn *code = *pcode;
883 int err = TP_ERR_BAD_VAR;
884 char *arg = orig_arg + 1;
885 unsigned long param;
886 int ret = 0;
887 int len;
888
889 if (ctx->flags & TPARG_FL_TEVENT) {
890 if (code->data)
891 return -EFAULT;
892 ret = parse_trace_event_arg(arg, code, ctx);
893 if (!ret)
894 return 0;
895 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
896 code->op = FETCH_OP_COMM;
897 return 0;
898 }
899 /* backward compatibility */
900 ctx->offset = 0;
901 goto inval;
902 }
903
904 if (str_has_prefix(arg, "retval")) {
905 if (!(ctx->flags & TPARG_FL_RETURN)) {
906 err = TP_ERR_RETVAL_ON_PROBE;
907 goto inval;
908 }
909 if (!(ctx->flags & TPARG_FL_KERNEL) ||
910 !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
911 code->op = FETCH_OP_RETVAL;
912 return 0;
913 }
914 return parse_btf_arg(orig_arg, pcode, end, ctx);
915 }
916
917 len = str_has_prefix(arg, "stack");
918 if (len) {
919
920 if (arg[len] == '\0') {
921 code->op = FETCH_OP_STACKP;
922 return 0;
923 }
924
925 if (isdigit(arg[len])) {
926 ret = kstrtoul(arg + len, 10, ¶m);
927 if (ret)
928 goto inval;
929
930 if ((ctx->flags & TPARG_FL_KERNEL) &&
931 param > PARAM_MAX_STACK) {
932 err = TP_ERR_BAD_STACK_NUM;
933 goto inval;
934 }
935 code->op = FETCH_OP_STACK;
936 code->param = (unsigned int)param;
937 return 0;
938 }
939 goto inval;
940 }
941
942 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
943 code->op = FETCH_OP_COMM;
944 return 0;
945 }
946
947#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
948 len = str_has_prefix(arg, "arg");
949 if (len) {
950 ret = kstrtoul(arg + len, 10, ¶m);
951 if (ret)
952 goto inval;
953
954 if (!param || param > PARAM_MAX_STACK) {
955 err = TP_ERR_BAD_ARG_NUM;
956 goto inval;
957 }
958 param--; /* argN starts from 1, but internal arg[N] starts from 0 */
959
960 if (tparg_is_function_entry(ctx->flags)) {
961 code->op = FETCH_OP_ARG;
962 code->param = (unsigned int)param;
963 /*
964 * The tracepoint probe will probe a stub function, and the
965 * first parameter of the stub is a dummy and should be ignored.
966 */
967 if (ctx->flags & TPARG_FL_TPOINT)
968 code->param++;
969 } else if (tparg_is_function_return(ctx->flags)) {
970 /* function entry argument access from return probe */
971 ret = __store_entry_arg(ctx->tp, param);
972 if (ret < 0) /* This error should be an internal error */
973 return ret;
974
975 code->op = FETCH_OP_EDATA;
976 code->offset = ret;
977 } else {
978 err = TP_ERR_NOFENTRY_ARGS;
979 goto inval;
980 }
981 return 0;
982 }
983#endif
984
985inval:
986 __trace_probe_log_err(ctx->offset, err);
987 return -EINVAL;
988}
989
990static int str_to_immediate(char *str, unsigned long *imm)
991{
992 if (isdigit(str[0]))
993 return kstrtoul(str, 0, imm);
994 else if (str[0] == '-')
995 return kstrtol(str, 0, (long *)imm);
996 else if (str[0] == '+')
997 return kstrtol(str + 1, 0, (long *)imm);
998 return -EINVAL;
999}
1000
1001static int __parse_imm_string(char *str, char **pbuf, int offs)
1002{
1003 size_t len = strlen(str);
1004
1005 if (str[len - 1] != '"') {
1006 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
1007 return -EINVAL;
1008 }
1009 *pbuf = kstrndup(str, len - 1, GFP_KERNEL);
1010 if (!*pbuf)
1011 return -ENOMEM;
1012 return 0;
1013}
1014
1015/* Recursive argument parser */
1016static int
1017parse_probe_arg(char *arg, const struct fetch_type *type,
1018 struct fetch_insn **pcode, struct fetch_insn *end,
1019 struct traceprobe_parse_context *ctx)
1020{
1021 struct fetch_insn *code = *pcode;
1022 unsigned long param;
1023 int deref = FETCH_OP_DEREF;
1024 long offset = 0;
1025 char *tmp;
1026 int ret = 0;
1027
1028 switch (arg[0]) {
1029 case '$':
1030 ret = parse_probe_vars(arg, type, pcode, end, ctx);
1031 break;
1032
1033 case '%': /* named register */
1034 if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
1035 /* eprobe and fprobe do not handle registers */
1036 trace_probe_log_err(ctx->offset, BAD_VAR);
1037 break;
1038 }
1039 ret = regs_query_register_offset(arg + 1);
1040 if (ret >= 0) {
1041 code->op = FETCH_OP_REG;
1042 code->param = (unsigned int)ret;
1043 ret = 0;
1044 } else
1045 trace_probe_log_err(ctx->offset, BAD_REG_NAME);
1046 break;
1047
1048 case '@': /* memory, file-offset or symbol */
1049 if (isdigit(arg[1])) {
1050 ret = kstrtoul(arg + 1, 0, ¶m);
1051 if (ret) {
1052 trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
1053 break;
1054 }
1055 /* load address */
1056 code->op = FETCH_OP_IMM;
1057 code->immediate = param;
1058 } else if (arg[1] == '+') {
1059 /* kprobes don't support file offsets */
1060 if (ctx->flags & TPARG_FL_KERNEL) {
1061 trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
1062 return -EINVAL;
1063 }
1064 ret = kstrtol(arg + 2, 0, &offset);
1065 if (ret) {
1066 trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
1067 break;
1068 }
1069
1070 code->op = FETCH_OP_FOFFS;
1071 code->immediate = (unsigned long)offset; // imm64?
1072 } else {
1073 /* uprobes don't support symbols */
1074 if (!(ctx->flags & TPARG_FL_KERNEL)) {
1075 trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
1076 return -EINVAL;
1077 }
1078 /* Preserve symbol for updating */
1079 code->op = FETCH_NOP_SYMBOL;
1080 code->data = kstrdup(arg + 1, GFP_KERNEL);
1081 if (!code->data)
1082 return -ENOMEM;
1083 if (++code == end) {
1084 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1085 return -EINVAL;
1086 }
1087 code->op = FETCH_OP_IMM;
1088 code->immediate = 0;
1089 }
1090 /* These are fetching from memory */
1091 if (++code == end) {
1092 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1093 return -EINVAL;
1094 }
1095 *pcode = code;
1096 code->op = FETCH_OP_DEREF;
1097 code->offset = offset;
1098 break;
1099
1100 case '+': /* deref memory */
1101 case '-':
1102 if (arg[1] == 'u') {
1103 deref = FETCH_OP_UDEREF;
1104 arg[1] = arg[0];
1105 arg++;
1106 }
1107 if (arg[0] == '+')
1108 arg++; /* Skip '+', because kstrtol() rejects it. */
1109 tmp = strchr(arg, '(');
1110 if (!tmp) {
1111 trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
1112 return -EINVAL;
1113 }
1114 *tmp = '\0';
1115 ret = kstrtol(arg, 0, &offset);
1116 if (ret) {
1117 trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
1118 break;
1119 }
1120 ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
1121 arg = tmp + 1;
1122 tmp = strrchr(arg, ')');
1123 if (!tmp) {
1124 trace_probe_log_err(ctx->offset + strlen(arg),
1125 DEREF_OPEN_BRACE);
1126 return -EINVAL;
1127 } else {
1128 const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags);
1129 int cur_offs = ctx->offset;
1130
1131 *tmp = '\0';
1132 ret = parse_probe_arg(arg, t2, &code, end, ctx);
1133 if (ret)
1134 break;
1135 ctx->offset = cur_offs;
1136 if (code->op == FETCH_OP_COMM ||
1137 code->op == FETCH_OP_DATA) {
1138 trace_probe_log_err(ctx->offset, COMM_CANT_DEREF);
1139 return -EINVAL;
1140 }
1141 if (++code == end) {
1142 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1143 return -EINVAL;
1144 }
1145 *pcode = code;
1146
1147 code->op = deref;
1148 code->offset = offset;
1149 /* Reset the last type if used */
1150 ctx->last_type = NULL;
1151 }
1152 break;
1153 case '\\': /* Immediate value */
1154 if (arg[1] == '"') { /* Immediate string */
1155 ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
1156 if (ret)
1157 break;
1158 code->op = FETCH_OP_DATA;
1159 code->data = tmp;
1160 } else {
1161 ret = str_to_immediate(arg + 1, &code->immediate);
1162 if (ret)
1163 trace_probe_log_err(ctx->offset + 1, BAD_IMM);
1164 else
1165 code->op = FETCH_OP_IMM;
1166 }
1167 break;
1168 default:
1169 if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */
1170 if (!tparg_is_function_entry(ctx->flags) &&
1171 !tparg_is_function_return(ctx->flags)) {
1172 trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
1173 return -EINVAL;
1174 }
1175 ret = parse_btf_arg(arg, pcode, end, ctx);
1176 break;
1177 }
1178 }
1179 if (!ret && code->op == FETCH_OP_NOP) {
1180 /* Parsed, but do not find fetch method */
1181 trace_probe_log_err(ctx->offset, BAD_FETCH_ARG);
1182 ret = -EINVAL;
1183 }
1184 return ret;
1185}
1186
1187#define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
1188
1189/* Bitfield type needs to be parsed into a fetch function */
1190static int __parse_bitfield_probe_arg(const char *bf,
1191 const struct fetch_type *t,
1192 struct fetch_insn **pcode)
1193{
1194 struct fetch_insn *code = *pcode;
1195 unsigned long bw, bo;
1196 char *tail;
1197
1198 if (*bf != 'b')
1199 return 0;
1200
1201 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
1202
1203 if (bw == 0 || *tail != '@')
1204 return -EINVAL;
1205
1206 bf = tail + 1;
1207 bo = simple_strtoul(bf, &tail, 0);
1208
1209 if (tail == bf || *tail != '/')
1210 return -EINVAL;
1211 code++;
1212 if (code->op != FETCH_OP_NOP)
1213 return -EINVAL;
1214 *pcode = code;
1215
1216 code->op = FETCH_OP_MOD_BF;
1217 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
1218 code->rshift = BYTES_TO_BITS(t->size) - bw;
1219 code->basesize = t->size;
1220
1221 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
1222}
1223
1224/* Split type part from @arg and return it. */
1225static char *parse_probe_arg_type(char *arg, struct probe_arg *parg,
1226 struct traceprobe_parse_context *ctx)
1227{
1228 char *t = NULL, *t2, *t3;
1229 int offs;
1230
1231 t = strchr(arg, ':');
1232 if (t) {
1233 *t++ = '\0';
1234 t2 = strchr(t, '[');
1235 if (t2) {
1236 *t2++ = '\0';
1237 t3 = strchr(t2, ']');
1238 if (!t3) {
1239 offs = t2 + strlen(t2) - arg;
1240
1241 trace_probe_log_err(ctx->offset + offs,
1242 ARRAY_NO_CLOSE);
1243 return ERR_PTR(-EINVAL);
1244 } else if (t3[1] != '\0') {
1245 trace_probe_log_err(ctx->offset + t3 + 1 - arg,
1246 BAD_ARRAY_SUFFIX);
1247 return ERR_PTR(-EINVAL);
1248 }
1249 *t3 = '\0';
1250 if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
1251 trace_probe_log_err(ctx->offset + t2 - arg,
1252 BAD_ARRAY_NUM);
1253 return ERR_PTR(-EINVAL);
1254 }
1255 if (parg->count > MAX_ARRAY_LEN) {
1256 trace_probe_log_err(ctx->offset + t2 - arg,
1257 ARRAY_TOO_BIG);
1258 return ERR_PTR(-EINVAL);
1259 }
1260 }
1261 }
1262 offs = t ? t - arg : 0;
1263
1264 /*
1265 * Since $comm and immediate string can not be dereferenced,
1266 * we can find those by strcmp. But ignore for eprobes.
1267 */
1268 if (!(ctx->flags & TPARG_FL_TEVENT) &&
1269 (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
1270 strncmp(arg, "\\\"", 2) == 0)) {
1271 /* The type of $comm must be "string", and not an array type. */
1272 if (parg->count || (t && strcmp(t, "string"))) {
1273 trace_probe_log_err(ctx->offset + offs, NEED_STRING_TYPE);
1274 return ERR_PTR(-EINVAL);
1275 }
1276 parg->type = find_fetch_type("string", ctx->flags);
1277 } else
1278 parg->type = find_fetch_type(t, ctx->flags);
1279
1280 if (!parg->type) {
1281 trace_probe_log_err(ctx->offset + offs, BAD_TYPE);
1282 return ERR_PTR(-EINVAL);
1283 }
1284
1285 return t;
1286}
1287
1288/* After parsing, adjust the fetch_insn according to the probe_arg */
1289static int finalize_fetch_insn(struct fetch_insn *code,
1290 struct probe_arg *parg,
1291 char *type,
1292 int type_offset,
1293 struct traceprobe_parse_context *ctx)
1294{
1295 struct fetch_insn *scode;
1296 int ret;
1297
1298 /* Store operation */
1299 if (parg->type->is_string) {
1300 /* Check bad combination of the type and the last fetch_insn. */
1301 if (!strcmp(parg->type->name, "symstr")) {
1302 if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
1303 code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
1304 code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
1305 trace_probe_log_err(ctx->offset + type_offset,
1306 BAD_SYMSTRING);
1307 return -EINVAL;
1308 }
1309 } else {
1310 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
1311 code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
1312 code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
1313 trace_probe_log_err(ctx->offset + type_offset,
1314 BAD_STRING);
1315 return -EINVAL;
1316 }
1317 }
1318
1319 if (!strcmp(parg->type->name, "symstr") ||
1320 (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
1321 code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
1322 parg->count) {
1323 /*
1324 * IMM, DATA and COMM is pointing actual address, those
1325 * must be kept, and if parg->count != 0, this is an
1326 * array of string pointers instead of string address
1327 * itself.
1328 * For the symstr, it doesn't need to dereference, thus
1329 * it just get the value.
1330 */
1331 code++;
1332 if (code->op != FETCH_OP_NOP) {
1333 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1334 return -EINVAL;
1335 }
1336 }
1337
1338 /* If op == DEREF, replace it with STRING */
1339 if (!strcmp(parg->type->name, "ustring") ||
1340 code->op == FETCH_OP_UDEREF)
1341 code->op = FETCH_OP_ST_USTRING;
1342 else if (!strcmp(parg->type->name, "symstr"))
1343 code->op = FETCH_OP_ST_SYMSTR;
1344 else
1345 code->op = FETCH_OP_ST_STRING;
1346 code->size = parg->type->size;
1347 parg->dynamic = true;
1348 } else if (code->op == FETCH_OP_DEREF) {
1349 code->op = FETCH_OP_ST_MEM;
1350 code->size = parg->type->size;
1351 } else if (code->op == FETCH_OP_UDEREF) {
1352 code->op = FETCH_OP_ST_UMEM;
1353 code->size = parg->type->size;
1354 } else {
1355 code++;
1356 if (code->op != FETCH_OP_NOP) {
1357 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1358 return -E2BIG;
1359 }
1360 code->op = FETCH_OP_ST_RAW;
1361 code->size = parg->type->size;
1362 }
1363
1364 /* Save storing fetch_insn. */
1365 scode = code;
1366
1367 /* Modify operation */
1368 if (type != NULL) {
1369 /* Bitfield needs a special fetch_insn. */
1370 ret = __parse_bitfield_probe_arg(type, parg->type, &code);
1371 if (ret) {
1372 trace_probe_log_err(ctx->offset + type_offset, BAD_BITFIELD);
1373 return ret;
1374 }
1375 } else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1376 ctx->last_type) {
1377 /* If user not specified the type, try parsing BTF bitfield. */
1378 ret = parse_btf_bitfield(&code, ctx);
1379 if (ret)
1380 return ret;
1381 }
1382
1383 /* Loop(Array) operation */
1384 if (parg->count) {
1385 if (scode->op != FETCH_OP_ST_MEM &&
1386 scode->op != FETCH_OP_ST_STRING &&
1387 scode->op != FETCH_OP_ST_USTRING) {
1388 trace_probe_log_err(ctx->offset + type_offset, BAD_STRING);
1389 return -EINVAL;
1390 }
1391 code++;
1392 if (code->op != FETCH_OP_NOP) {
1393 trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1394 return -E2BIG;
1395 }
1396 code->op = FETCH_OP_LP_ARRAY;
1397 code->param = parg->count;
1398 }
1399
1400 /* Finalize the fetch_insn array. */
1401 code++;
1402 code->op = FETCH_OP_END;
1403
1404 return 0;
1405}
1406
1407/* String length checking wrapper */
1408static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
1409 struct probe_arg *parg,
1410 struct traceprobe_parse_context *ctx)
1411{
1412 struct fetch_insn *code, *tmp = NULL;
1413 char *type, *arg;
1414 int ret, len;
1415
1416 len = strlen(argv);
1417 if (len > MAX_ARGSTR_LEN) {
1418 trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
1419 return -E2BIG;
1420 } else if (len == 0) {
1421 trace_probe_log_err(ctx->offset, NO_ARG_BODY);
1422 return -EINVAL;
1423 }
1424
1425 arg = kstrdup(argv, GFP_KERNEL);
1426 if (!arg)
1427 return -ENOMEM;
1428
1429 parg->comm = kstrdup(arg, GFP_KERNEL);
1430 if (!parg->comm) {
1431 ret = -ENOMEM;
1432 goto out;
1433 }
1434
1435 type = parse_probe_arg_type(arg, parg, ctx);
1436 if (IS_ERR(type)) {
1437 ret = PTR_ERR(type);
1438 goto out;
1439 }
1440
1441 code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
1442 if (!code) {
1443 ret = -ENOMEM;
1444 goto out;
1445 }
1446 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
1447
1448 ctx->last_type = NULL;
1449 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
1450 ctx);
1451 if (ret < 0)
1452 goto fail;
1453
1454 /* Update storing type if BTF is available */
1455 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1456 ctx->last_type) {
1457 if (!type) {
1458 parg->type = find_fetch_type_from_btf_type(ctx);
1459 } else if (strstr(type, "string")) {
1460 ret = check_prepare_btf_string_fetch(type, &code, ctx);
1461 if (ret)
1462 goto fail;
1463 }
1464 }
1465 parg->offset = *size;
1466 *size += parg->type->size * (parg->count ?: 1);
1467
1468 if (parg->count) {
1469 len = strlen(parg->type->fmttype) + 6;
1470 parg->fmt = kmalloc(len, GFP_KERNEL);
1471 if (!parg->fmt) {
1472 ret = -ENOMEM;
1473 goto fail;
1474 }
1475 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
1476 parg->count);
1477 }
1478
1479 ret = finalize_fetch_insn(code, parg, type, type ? type - arg : 0, ctx);
1480 if (ret < 0)
1481 goto fail;
1482
1483 for (; code < tmp + FETCH_INSN_MAX; code++)
1484 if (code->op == FETCH_OP_END)
1485 break;
1486 /* Shrink down the code buffer */
1487 parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
1488 if (!parg->code)
1489 ret = -ENOMEM;
1490 else
1491 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
1492
1493fail:
1494 if (ret < 0) {
1495 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
1496 if (code->op == FETCH_NOP_SYMBOL ||
1497 code->op == FETCH_OP_DATA)
1498 kfree(code->data);
1499 }
1500 kfree(tmp);
1501out:
1502 kfree(arg);
1503
1504 return ret;
1505}
1506
1507/* Return 1 if name is reserved or already used by another argument */
1508static int traceprobe_conflict_field_name(const char *name,
1509 struct probe_arg *args, int narg)
1510{
1511 int i;
1512
1513 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1514 if (strcmp(reserved_field_names[i], name) == 0)
1515 return 1;
1516
1517 for (i = 0; i < narg; i++)
1518 if (strcmp(args[i].name, name) == 0)
1519 return 1;
1520
1521 return 0;
1522}
1523
1524static char *generate_probe_arg_name(const char *arg, int idx)
1525{
1526 char *name = NULL;
1527 const char *end;
1528
1529 /*
1530 * If argument name is omitted, try arg as a name (BTF variable)
1531 * or "argN".
1532 */
1533 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
1534 end = strchr(arg, ':');
1535 if (!end)
1536 end = arg + strlen(arg);
1537
1538 name = kmemdup_nul(arg, end - arg, GFP_KERNEL);
1539 if (!name || !is_good_name(name)) {
1540 kfree(name);
1541 name = NULL;
1542 }
1543 }
1544
1545 if (!name)
1546 name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
1547
1548 return name;
1549}
1550
1551int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
1552 struct traceprobe_parse_context *ctx)
1553{
1554 struct probe_arg *parg = &tp->args[i];
1555 const char *body;
1556
1557 ctx->tp = tp;
1558 body = strchr(arg, '=');
1559 if (body) {
1560 if (body - arg > MAX_ARG_NAME_LEN) {
1561 trace_probe_log_err(0, ARG_NAME_TOO_LONG);
1562 return -EINVAL;
1563 } else if (body == arg) {
1564 trace_probe_log_err(0, NO_ARG_NAME);
1565 return -EINVAL;
1566 }
1567 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
1568 body++;
1569 } else {
1570 parg->name = generate_probe_arg_name(arg, i);
1571 body = arg;
1572 }
1573 if (!parg->name)
1574 return -ENOMEM;
1575
1576 if (!is_good_name(parg->name)) {
1577 trace_probe_log_err(0, BAD_ARG_NAME);
1578 return -EINVAL;
1579 }
1580 if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
1581 trace_probe_log_err(0, USED_ARG_NAME);
1582 return -EINVAL;
1583 }
1584 ctx->offset = body - arg;
1585 /* Parse fetch argument */
1586 return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);
1587}
1588
1589void traceprobe_free_probe_arg(struct probe_arg *arg)
1590{
1591 struct fetch_insn *code = arg->code;
1592
1593 while (code && code->op != FETCH_OP_END) {
1594 if (code->op == FETCH_NOP_SYMBOL ||
1595 code->op == FETCH_OP_DATA)
1596 kfree(code->data);
1597 code++;
1598 }
1599 kfree(arg->code);
1600 kfree(arg->name);
1601 kfree(arg->comm);
1602 kfree(arg->fmt);
1603}
1604
1605static int argv_has_var_arg(int argc, const char *argv[], int *args_idx,
1606 struct traceprobe_parse_context *ctx)
1607{
1608 int i, found = 0;
1609
1610 for (i = 0; i < argc; i++)
1611 if (str_has_prefix(argv[i], "$arg")) {
1612 trace_probe_log_set_index(i + 2);
1613
1614 if (!tparg_is_function_entry(ctx->flags) &&
1615 !tparg_is_function_return(ctx->flags)) {
1616 trace_probe_log_err(0, NOFENTRY_ARGS);
1617 return -EINVAL;
1618 }
1619
1620 if (isdigit(argv[i][4])) {
1621 found = 1;
1622 continue;
1623 }
1624
1625 if (argv[i][4] != '*') {
1626 trace_probe_log_err(0, BAD_VAR);
1627 return -EINVAL;
1628 }
1629
1630 if (*args_idx >= 0 && *args_idx < argc) {
1631 trace_probe_log_err(0, DOUBLE_ARGS);
1632 return -EINVAL;
1633 }
1634 found = 1;
1635 *args_idx = i;
1636 }
1637
1638 return found;
1639}
1640
1641static int sprint_nth_btf_arg(int idx, const char *type,
1642 char *buf, int bufsize,
1643 struct traceprobe_parse_context *ctx)
1644{
1645 const char *name;
1646 int ret;
1647
1648 if (idx >= ctx->nr_params) {
1649 trace_probe_log_err(0, NO_BTFARG);
1650 return -ENOENT;
1651 }
1652 name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off);
1653 if (!name) {
1654 trace_probe_log_err(0, NO_BTF_ENTRY);
1655 return -ENOENT;
1656 }
1657 ret = snprintf(buf, bufsize, "%s%s", name, type);
1658 if (ret >= bufsize) {
1659 trace_probe_log_err(0, ARGS_2LONG);
1660 return -E2BIG;
1661 }
1662 return ret;
1663}
1664
1665/* Return new_argv which must be freed after use */
1666const char **traceprobe_expand_meta_args(int argc, const char *argv[],
1667 int *new_argc, char *buf, int bufsize,
1668 struct traceprobe_parse_context *ctx)
1669{
1670 const struct btf_param *params = NULL;
1671 int i, j, n, used, ret, args_idx = -1;
1672 const char **new_argv = NULL;
1673
1674 ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
1675 if (ret < 0)
1676 return ERR_PTR(ret);
1677
1678 if (!ret) {
1679 *new_argc = argc;
1680 return NULL;
1681 }
1682
1683 ret = query_btf_context(ctx);
1684 if (ret < 0 || ctx->nr_params == 0) {
1685 if (args_idx != -1) {
1686 /* $arg* requires BTF info */
1687 trace_probe_log_err(0, NOSUP_BTFARG);
1688 return (const char **)params;
1689 }
1690 *new_argc = argc;
1691 return NULL;
1692 }
1693
1694 if (args_idx >= 0)
1695 *new_argc = argc + ctx->nr_params - 1;
1696 else
1697 *new_argc = argc;
1698
1699 new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL);
1700 if (!new_argv)
1701 return ERR_PTR(-ENOMEM);
1702
1703 used = 0;
1704 for (i = 0, j = 0; i < argc; i++) {
1705 trace_probe_log_set_index(i + 2);
1706 if (i == args_idx) {
1707 for (n = 0; n < ctx->nr_params; n++) {
1708 ret = sprint_nth_btf_arg(n, "", buf + used,
1709 bufsize - used, ctx);
1710 if (ret < 0)
1711 goto error;
1712
1713 new_argv[j++] = buf + used;
1714 used += ret + 1;
1715 }
1716 continue;
1717 }
1718
1719 if (str_has_prefix(argv[i], "$arg")) {
1720 char *type = NULL;
1721
1722 n = simple_strtoul(argv[i] + 4, &type, 10);
1723 if (type && !(*type == ':' || *type == '\0')) {
1724 trace_probe_log_err(0, BAD_VAR);
1725 ret = -ENOENT;
1726 goto error;
1727 }
1728 /* Note: $argN starts from $arg1 */
1729 ret = sprint_nth_btf_arg(n - 1, type, buf + used,
1730 bufsize - used, ctx);
1731 if (ret < 0)
1732 goto error;
1733 new_argv[j++] = buf + used;
1734 used += ret + 1;
1735 } else
1736 new_argv[j++] = argv[i];
1737 }
1738
1739 return new_argv;
1740
1741error:
1742 kfree(new_argv);
1743 return ERR_PTR(ret);
1744}
1745
1746void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
1747{
1748 clear_btf_context(ctx);
1749}
1750
1751int traceprobe_update_arg(struct probe_arg *arg)
1752{
1753 struct fetch_insn *code = arg->code;
1754 long offset;
1755 char *tmp;
1756 char c;
1757 int ret = 0;
1758
1759 while (code && code->op != FETCH_OP_END) {
1760 if (code->op == FETCH_NOP_SYMBOL) {
1761 if (code[1].op != FETCH_OP_IMM)
1762 return -EINVAL;
1763
1764 tmp = strpbrk(code->data, "+-");
1765 if (tmp)
1766 c = *tmp;
1767 ret = traceprobe_split_symbol_offset(code->data,
1768 &offset);
1769 if (ret)
1770 return ret;
1771
1772 code[1].immediate =
1773 (unsigned long)kallsyms_lookup_name(code->data);
1774 if (tmp)
1775 *tmp = c;
1776 if (!code[1].immediate)
1777 return -ENOENT;
1778 code[1].immediate += offset;
1779 }
1780 code++;
1781 }
1782 return 0;
1783}
1784
1785/* When len=0, we just calculate the needed length */
1786#define LEN_OR_ZERO (len ? len - pos : 0)
1787static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
1788 enum probe_print_type ptype)
1789{
1790 struct probe_arg *parg;
1791 int i, j;
1792 int pos = 0;
1793 const char *fmt, *arg;
1794
1795 switch (ptype) {
1796 case PROBE_PRINT_NORMAL:
1797 fmt = "(%lx)";
1798 arg = ", REC->" FIELD_STRING_IP;
1799 break;
1800 case PROBE_PRINT_RETURN:
1801 fmt = "(%lx <- %lx)";
1802 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1803 break;
1804 case PROBE_PRINT_EVENT:
1805 fmt = "";
1806 arg = "";
1807 break;
1808 default:
1809 WARN_ON_ONCE(1);
1810 return 0;
1811 }
1812
1813 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1814
1815 for (i = 0; i < tp->nr_args; i++) {
1816 parg = tp->args + i;
1817 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
1818 if (parg->count) {
1819 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
1820 parg->type->fmt);
1821 for (j = 1; j < parg->count; j++)
1822 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
1823 parg->type->fmt);
1824 pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
1825 } else
1826 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
1827 parg->type->fmt);
1828 }
1829
1830 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
1831
1832 for (i = 0; i < tp->nr_args; i++) {
1833 parg = tp->args + i;
1834 if (parg->count) {
1835 if (parg->type->is_string)
1836 fmt = ", __get_str(%s[%d])";
1837 else
1838 fmt = ", REC->%s[%d]";
1839 for (j = 0; j < parg->count; j++)
1840 pos += snprintf(buf + pos, LEN_OR_ZERO,
1841 fmt, parg->name, j);
1842 } else {
1843 if (parg->type->is_string)
1844 fmt = ", __get_str(%s)";
1845 else
1846 fmt = ", REC->%s";
1847 pos += snprintf(buf + pos, LEN_OR_ZERO,
1848 fmt, parg->name);
1849 }
1850 }
1851
1852 /* return the length of print_fmt */
1853 return pos;
1854}
1855#undef LEN_OR_ZERO
1856
1857int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
1858{
1859 struct trace_event_call *call = trace_probe_event_call(tp);
1860 int len;
1861 char *print_fmt;
1862
1863 /* First: called with 0 length to calculate the needed length */
1864 len = __set_print_fmt(tp, NULL, 0, ptype);
1865 print_fmt = kmalloc(len + 1, GFP_KERNEL);
1866 if (!print_fmt)
1867 return -ENOMEM;
1868
1869 /* Second: actually write the @print_fmt */
1870 __set_print_fmt(tp, print_fmt, len + 1, ptype);
1871 call->print_fmt = print_fmt;
1872
1873 return 0;
1874}
1875
1876int traceprobe_define_arg_fields(struct trace_event_call *event_call,
1877 size_t offset, struct trace_probe *tp)
1878{
1879 int ret, i;
1880
1881 /* Set argument names as fields */
1882 for (i = 0; i < tp->nr_args; i++) {
1883 struct probe_arg *parg = &tp->args[i];
1884 const char *fmt = parg->type->fmttype;
1885 int size = parg->type->size;
1886
1887 if (parg->fmt)
1888 fmt = parg->fmt;
1889 if (parg->count)
1890 size *= parg->count;
1891 ret = trace_define_field(event_call, fmt, parg->name,
1892 offset + parg->offset, size,
1893 parg->type->is_signed,
1894 FILTER_OTHER);
1895 if (ret)
1896 return ret;
1897 }
1898 return 0;
1899}
1900
1901static void trace_probe_event_free(struct trace_probe_event *tpe)
1902{
1903 kfree(tpe->class.system);
1904 kfree(tpe->call.name);
1905 kfree(tpe->call.print_fmt);
1906 kfree(tpe);
1907}
1908
1909int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
1910{
1911 if (trace_probe_has_sibling(tp))
1912 return -EBUSY;
1913
1914 list_del_init(&tp->list);
1915 trace_probe_event_free(tp->event);
1916
1917 tp->event = to->event;
1918 list_add_tail(&tp->list, trace_probe_probe_list(to));
1919
1920 return 0;
1921}
1922
1923void trace_probe_unlink(struct trace_probe *tp)
1924{
1925 list_del_init(&tp->list);
1926 if (list_empty(trace_probe_probe_list(tp)))
1927 trace_probe_event_free(tp->event);
1928 tp->event = NULL;
1929}
1930
1931void trace_probe_cleanup(struct trace_probe *tp)
1932{
1933 int i;
1934
1935 for (i = 0; i < tp->nr_args; i++)
1936 traceprobe_free_probe_arg(&tp->args[i]);
1937
1938 if (tp->entry_arg) {
1939 kfree(tp->entry_arg->code);
1940 kfree(tp->entry_arg);
1941 tp->entry_arg = NULL;
1942 }
1943
1944 if (tp->event)
1945 trace_probe_unlink(tp);
1946}
1947
1948int trace_probe_init(struct trace_probe *tp, const char *event,
1949 const char *group, bool alloc_filter, int nargs)
1950{
1951 struct trace_event_call *call;
1952 size_t size = sizeof(struct trace_probe_event);
1953 int ret = 0;
1954
1955 if (!event || !group)
1956 return -EINVAL;
1957
1958 if (alloc_filter)
1959 size += sizeof(struct trace_uprobe_filter);
1960
1961 tp->event = kzalloc(size, GFP_KERNEL);
1962 if (!tp->event)
1963 return -ENOMEM;
1964
1965 INIT_LIST_HEAD(&tp->event->files);
1966 INIT_LIST_HEAD(&tp->event->class.fields);
1967 INIT_LIST_HEAD(&tp->event->probes);
1968 INIT_LIST_HEAD(&tp->list);
1969 list_add(&tp->list, &tp->event->probes);
1970
1971 call = trace_probe_event_call(tp);
1972 call->class = &tp->event->class;
1973 call->name = kstrdup(event, GFP_KERNEL);
1974 if (!call->name) {
1975 ret = -ENOMEM;
1976 goto error;
1977 }
1978
1979 tp->event->class.system = kstrdup(group, GFP_KERNEL);
1980 if (!tp->event->class.system) {
1981 ret = -ENOMEM;
1982 goto error;
1983 }
1984
1985 tp->nr_args = nargs;
1986 /* Make sure pointers in args[] are NULL */
1987 if (nargs)
1988 memset(tp->args, 0, sizeof(tp->args[0]) * nargs);
1989
1990 return 0;
1991
1992error:
1993 trace_probe_cleanup(tp);
1994 return ret;
1995}
1996
1997static struct trace_event_call *
1998find_trace_event_call(const char *system, const char *event_name)
1999{
2000 struct trace_event_call *tp_event;
2001 const char *name;
2002
2003 list_for_each_entry(tp_event, &ftrace_events, list) {
2004 if (!tp_event->class->system ||
2005 strcmp(system, tp_event->class->system))
2006 continue;
2007 name = trace_event_name(tp_event);
2008 if (!name || strcmp(event_name, name))
2009 continue;
2010 return tp_event;
2011 }
2012
2013 return NULL;
2014}
2015
2016int trace_probe_register_event_call(struct trace_probe *tp)
2017{
2018 struct trace_event_call *call = trace_probe_event_call(tp);
2019 int ret;
2020
2021 lockdep_assert_held(&event_mutex);
2022
2023 if (find_trace_event_call(trace_probe_group_name(tp),
2024 trace_probe_name(tp)))
2025 return -EEXIST;
2026
2027 ret = register_trace_event(&call->event);
2028 if (!ret)
2029 return -ENODEV;
2030
2031 ret = trace_add_event_call(call);
2032 if (ret)
2033 unregister_trace_event(&call->event);
2034
2035 return ret;
2036}
2037
2038int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
2039{
2040 struct event_file_link *link;
2041
2042 link = kmalloc(sizeof(*link), GFP_KERNEL);
2043 if (!link)
2044 return -ENOMEM;
2045
2046 link->file = file;
2047 INIT_LIST_HEAD(&link->list);
2048 list_add_tail_rcu(&link->list, &tp->event->files);
2049 trace_probe_set_flag(tp, TP_FLAG_TRACE);
2050 return 0;
2051}
2052
2053struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
2054 struct trace_event_file *file)
2055{
2056 struct event_file_link *link;
2057
2058 trace_probe_for_each_link(link, tp) {
2059 if (link->file == file)
2060 return link;
2061 }
2062
2063 return NULL;
2064}
2065
2066int trace_probe_remove_file(struct trace_probe *tp,
2067 struct trace_event_file *file)
2068{
2069 struct event_file_link *link;
2070
2071 link = trace_probe_get_file_link(tp, file);
2072 if (!link)
2073 return -ENOENT;
2074
2075 list_del_rcu(&link->list);
2076 kvfree_rcu_mightsleep(link);
2077
2078 if (list_empty(&tp->event->files))
2079 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
2080
2081 return 0;
2082}
2083
2084/*
2085 * Return the smallest index of different type argument (start from 1).
2086 * If all argument types and name are same, return 0.
2087 */
2088int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
2089{
2090 int i;
2091
2092 /* In case of more arguments */
2093 if (a->nr_args < b->nr_args)
2094 return a->nr_args + 1;
2095 if (a->nr_args > b->nr_args)
2096 return b->nr_args + 1;
2097
2098 for (i = 0; i < a->nr_args; i++) {
2099 if ((b->nr_args <= i) ||
2100 ((a->args[i].type != b->args[i].type) ||
2101 (a->args[i].count != b->args[i].count) ||
2102 strcmp(a->args[i].name, b->args[i].name)))
2103 return i + 1;
2104 }
2105
2106 return 0;
2107}
2108
2109bool trace_probe_match_command_args(struct trace_probe *tp,
2110 int argc, const char **argv)
2111{
2112 char buf[MAX_ARGSTR_LEN + 1];
2113 int i;
2114
2115 if (tp->nr_args < argc)
2116 return false;
2117
2118 for (i = 0; i < argc; i++) {
2119 snprintf(buf, sizeof(buf), "%s=%s",
2120 tp->args[i].name, tp->args[i].comm);
2121 if (strcmp(buf, argv[i]))
2122 return false;
2123 }
2124 return true;
2125}
2126
2127int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
2128{
2129 int argc = 0, ret = 0;
2130 char **argv;
2131
2132 argv = argv_split(GFP_KERNEL, raw_command, &argc);
2133 if (!argv)
2134 return -ENOMEM;
2135
2136 if (argc)
2137 ret = createfn(argc, (const char **)argv);
2138
2139 argv_free(argv);
2140
2141 return ret;
2142}
2143
2144int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
2145 u8 *data, void *field)
2146{
2147 void *p;
2148 int i, j;
2149
2150 for (i = 0; i < nr_args; i++) {
2151 struct probe_arg *a = args + i;
2152
2153 trace_seq_printf(s, " %s=", a->name);
2154 if (likely(!a->count)) {
2155 if (!a->type->print(s, data + a->offset, field))
2156 return -ENOMEM;
2157 continue;
2158 }
2159 trace_seq_putc(s, '{');
2160 p = data + a->offset;
2161 for (j = 0; j < a->count; j++) {
2162 if (!a->type->print(s, p, field))
2163 return -ENOMEM;
2164 trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
2165 p += a->type->size;
2166 }
2167 }
2168 return 0;
2169}