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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(tname, type, fmt) \
40int PRINT_TYPE_FUNC_NAME(tname)(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(tname)[] = fmt; \
47NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(tname));
48
49DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u")
50DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
51DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
52DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
53DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d")
54DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
55DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
56DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
57DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x")
58DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
59DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
60DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
61
62/* Print type function for string type */
63int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
64 void *data, void *ent)
65{
66 int len = *(u32 *)data >> 16;
67
68 if (!len)
69 trace_seq_printf(s, " %s=(fault)", name);
70 else
71 trace_seq_printf(s, " %s=\"%s\"", name,
72 (const char *)get_loc_data(data, ent));
73 return !trace_seq_has_overflowed(s);
74}
75NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string));
76
77const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
78
79#define CHECK_FETCH_FUNCS(method, fn) \
80 (((FETCH_FUNC_NAME(method, u8) == fn) || \
81 (FETCH_FUNC_NAME(method, u16) == fn) || \
82 (FETCH_FUNC_NAME(method, u32) == fn) || \
83 (FETCH_FUNC_NAME(method, u64) == fn) || \
84 (FETCH_FUNC_NAME(method, string) == fn) || \
85 (FETCH_FUNC_NAME(method, string_size) == fn)) \
86 && (fn != NULL))
87
88/* Data fetch function templates */
89#define DEFINE_FETCH_reg(type) \
90void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, void *offset, void *dest) \
91{ \
92 *(type *)dest = (type)regs_get_register(regs, \
93 (unsigned int)((unsigned long)offset)); \
94} \
95NOKPROBE_SYMBOL(FETCH_FUNC_NAME(reg, type));
96DEFINE_BASIC_FETCH_FUNCS(reg)
97/* No string on the register */
98#define fetch_reg_string NULL
99#define fetch_reg_string_size NULL
100
101#define DEFINE_FETCH_retval(type) \
102void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs, \
103 void *dummy, void *dest) \
104{ \
105 *(type *)dest = (type)regs_return_value(regs); \
106} \
107NOKPROBE_SYMBOL(FETCH_FUNC_NAME(retval, type));
108DEFINE_BASIC_FETCH_FUNCS(retval)
109/* No string on the retval */
110#define fetch_retval_string NULL
111#define fetch_retval_string_size NULL
112
113/* Dereference memory access function */
114struct deref_fetch_param {
115 struct fetch_param orig;
116 long offset;
117 fetch_func_t fetch;
118 fetch_func_t fetch_size;
119};
120
121#define DEFINE_FETCH_deref(type) \
122void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs, \
123 void *data, void *dest) \
124{ \
125 struct deref_fetch_param *dprm = data; \
126 unsigned long addr; \
127 call_fetch(&dprm->orig, regs, &addr); \
128 if (addr) { \
129 addr += dprm->offset; \
130 dprm->fetch(regs, (void *)addr, dest); \
131 } else \
132 *(type *)dest = 0; \
133} \
134NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, type));
135DEFINE_BASIC_FETCH_FUNCS(deref)
136DEFINE_FETCH_deref(string)
137
138void FETCH_FUNC_NAME(deref, string_size)(struct pt_regs *regs,
139 void *data, void *dest)
140{
141 struct deref_fetch_param *dprm = data;
142 unsigned long addr;
143
144 call_fetch(&dprm->orig, regs, &addr);
145 if (addr && dprm->fetch_size) {
146 addr += dprm->offset;
147 dprm->fetch_size(regs, (void *)addr, dest);
148 } else
149 *(string_size *)dest = 0;
150}
151NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, string_size));
152
153static void update_deref_fetch_param(struct deref_fetch_param *data)
154{
155 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
156 update_deref_fetch_param(data->orig.data);
157 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
158 update_symbol_cache(data->orig.data);
159}
160NOKPROBE_SYMBOL(update_deref_fetch_param);
161
162static void free_deref_fetch_param(struct deref_fetch_param *data)
163{
164 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
165 free_deref_fetch_param(data->orig.data);
166 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
167 free_symbol_cache(data->orig.data);
168 kfree(data);
169}
170NOKPROBE_SYMBOL(free_deref_fetch_param);
171
172/* Bitfield fetch function */
173struct bitfield_fetch_param {
174 struct fetch_param orig;
175 unsigned char hi_shift;
176 unsigned char low_shift;
177};
178
179#define DEFINE_FETCH_bitfield(type) \
180void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs, \
181 void *data, void *dest) \
182{ \
183 struct bitfield_fetch_param *bprm = data; \
184 type buf = 0; \
185 call_fetch(&bprm->orig, regs, &buf); \
186 if (buf) { \
187 buf <<= bprm->hi_shift; \
188 buf >>= bprm->low_shift; \
189 } \
190 *(type *)dest = buf; \
191} \
192NOKPROBE_SYMBOL(FETCH_FUNC_NAME(bitfield, type));
193DEFINE_BASIC_FETCH_FUNCS(bitfield)
194#define fetch_bitfield_string NULL
195#define fetch_bitfield_string_size NULL
196
197static void
198update_bitfield_fetch_param(struct bitfield_fetch_param *data)
199{
200 /*
201 * Don't check the bitfield itself, because this must be the
202 * last fetch function.
203 */
204 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
205 update_deref_fetch_param(data->orig.data);
206 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
207 update_symbol_cache(data->orig.data);
208}
209
210static void
211free_bitfield_fetch_param(struct bitfield_fetch_param *data)
212{
213 /*
214 * Don't check the bitfield itself, because this must be the
215 * last fetch function.
216 */
217 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
218 free_deref_fetch_param(data->orig.data);
219 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
220 free_symbol_cache(data->orig.data);
221
222 kfree(data);
223}
224
225void FETCH_FUNC_NAME(comm, string)(struct pt_regs *regs,
226 void *data, void *dest)
227{
228 int maxlen = get_rloc_len(*(u32 *)dest);
229 u8 *dst = get_rloc_data(dest);
230 long ret;
231
232 if (!maxlen)
233 return;
234
235 ret = strlcpy(dst, current->comm, maxlen);
236 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
237}
238NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string));
239
240void FETCH_FUNC_NAME(comm, string_size)(struct pt_regs *regs,
241 void *data, void *dest)
242{
243 *(u32 *)dest = strlen(current->comm) + 1;
244}
245NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string_size));
246
247static const struct fetch_type *find_fetch_type(const char *type,
248 const struct fetch_type *ftbl)
249{
250 int i;
251
252 if (!type)
253 type = DEFAULT_FETCH_TYPE_STR;
254
255 /* Special case: bitfield */
256 if (*type == 'b') {
257 unsigned long bs;
258
259 type = strchr(type, '/');
260 if (!type)
261 goto fail;
262
263 type++;
264 if (kstrtoul(type, 0, &bs))
265 goto fail;
266
267 switch (bs) {
268 case 8:
269 return find_fetch_type("u8", ftbl);
270 case 16:
271 return find_fetch_type("u16", ftbl);
272 case 32:
273 return find_fetch_type("u32", ftbl);
274 case 64:
275 return find_fetch_type("u64", ftbl);
276 default:
277 goto fail;
278 }
279 }
280
281 for (i = 0; ftbl[i].name; i++) {
282 if (strcmp(type, ftbl[i].name) == 0)
283 return &ftbl[i];
284 }
285
286fail:
287 return NULL;
288}
289
290/* Special function : only accept unsigned long */
291static void fetch_kernel_stack_address(struct pt_regs *regs, void *dummy, void *dest)
292{
293 *(unsigned long *)dest = kernel_stack_pointer(regs);
294}
295NOKPROBE_SYMBOL(fetch_kernel_stack_address);
296
297static void fetch_user_stack_address(struct pt_regs *regs, void *dummy, void *dest)
298{
299 *(unsigned long *)dest = user_stack_pointer(regs);
300}
301NOKPROBE_SYMBOL(fetch_user_stack_address);
302
303static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
304 fetch_func_t orig_fn,
305 const struct fetch_type *ftbl)
306{
307 int i;
308
309 if (type != &ftbl[FETCH_TYPE_STRING])
310 return NULL; /* Only string type needs size function */
311
312 for (i = 0; i < FETCH_MTD_END; i++)
313 if (type->fetch[i] == orig_fn)
314 return ftbl[FETCH_TYPE_STRSIZE].fetch[i];
315
316 WARN_ON(1); /* This should not happen */
317
318 return NULL;
319}
320
321/* Split symbol and offset. */
322int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
323{
324 char *tmp;
325 int ret;
326
327 if (!offset)
328 return -EINVAL;
329
330 tmp = strchr(symbol, '+');
331 if (tmp) {
332 /* skip sign because kstrtoul doesn't accept '+' */
333 ret = kstrtoul(tmp + 1, 0, offset);
334 if (ret)
335 return ret;
336
337 *tmp = '\0';
338 } else
339 *offset = 0;
340
341 return 0;
342}
343
344#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
345
346static int parse_probe_vars(char *arg, const struct fetch_type *t,
347 struct fetch_param *f, bool is_return,
348 bool is_kprobe)
349{
350 int ret = 0;
351 unsigned long param;
352
353 if (strcmp(arg, "retval") == 0) {
354 if (is_return)
355 f->fn = t->fetch[FETCH_MTD_retval];
356 else
357 ret = -EINVAL;
358 } else if (strncmp(arg, "stack", 5) == 0) {
359 if (arg[5] == '\0') {
360 if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR))
361 return -EINVAL;
362
363 if (is_kprobe)
364 f->fn = fetch_kernel_stack_address;
365 else
366 f->fn = fetch_user_stack_address;
367 } else if (isdigit(arg[5])) {
368 ret = kstrtoul(arg + 5, 10, ¶m);
369 if (ret || (is_kprobe && param > PARAM_MAX_STACK))
370 ret = -EINVAL;
371 else {
372 f->fn = t->fetch[FETCH_MTD_stack];
373 f->data = (void *)param;
374 }
375 } else
376 ret = -EINVAL;
377 } else if (strcmp(arg, "comm") == 0) {
378 if (strcmp(t->name, "string") != 0 &&
379 strcmp(t->name, "string_size") != 0)
380 return -EINVAL;
381 f->fn = t->fetch[FETCH_MTD_comm];
382 } else
383 ret = -EINVAL;
384
385 return ret;
386}
387
388/* Recursive argument parser */
389static int parse_probe_arg(char *arg, const struct fetch_type *t,
390 struct fetch_param *f, bool is_return, bool is_kprobe,
391 const struct fetch_type *ftbl)
392{
393 unsigned long param;
394 long offset;
395 char *tmp;
396 int ret = 0;
397
398 switch (arg[0]) {
399 case '$':
400 ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
401 break;
402
403 case '%': /* named register */
404 ret = regs_query_register_offset(arg + 1);
405 if (ret >= 0) {
406 f->fn = t->fetch[FETCH_MTD_reg];
407 f->data = (void *)(unsigned long)ret;
408 ret = 0;
409 }
410 break;
411
412 case '@': /* memory, file-offset or symbol */
413 if (isdigit(arg[1])) {
414 ret = kstrtoul(arg + 1, 0, ¶m);
415 if (ret)
416 break;
417
418 f->fn = t->fetch[FETCH_MTD_memory];
419 f->data = (void *)param;
420 } else if (arg[1] == '+') {
421 /* kprobes don't support file offsets */
422 if (is_kprobe)
423 return -EINVAL;
424
425 ret = kstrtol(arg + 2, 0, &offset);
426 if (ret)
427 break;
428
429 f->fn = t->fetch[FETCH_MTD_file_offset];
430 f->data = (void *)offset;
431 } else {
432 /* uprobes don't support symbols */
433 if (!is_kprobe)
434 return -EINVAL;
435
436 ret = traceprobe_split_symbol_offset(arg + 1, &offset);
437 if (ret)
438 break;
439
440 f->data = alloc_symbol_cache(arg + 1, offset);
441 if (f->data)
442 f->fn = t->fetch[FETCH_MTD_symbol];
443 }
444 break;
445
446 case '+': /* deref memory */
447 arg++; /* Skip '+', because kstrtol() rejects it. */
448 case '-':
449 tmp = strchr(arg, '(');
450 if (!tmp)
451 break;
452
453 *tmp = '\0';
454 ret = kstrtol(arg, 0, &offset);
455
456 if (ret)
457 break;
458
459 arg = tmp + 1;
460 tmp = strrchr(arg, ')');
461
462 if (tmp) {
463 struct deref_fetch_param *dprm;
464 const struct fetch_type *t2;
465
466 t2 = find_fetch_type(NULL, ftbl);
467 *tmp = '\0';
468 dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL);
469
470 if (!dprm)
471 return -ENOMEM;
472
473 dprm->offset = offset;
474 dprm->fetch = t->fetch[FETCH_MTD_memory];
475 dprm->fetch_size = get_fetch_size_function(t,
476 dprm->fetch, ftbl);
477 ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
478 is_kprobe, ftbl);
479 if (ret)
480 kfree(dprm);
481 else {
482 f->fn = t->fetch[FETCH_MTD_deref];
483 f->data = (void *)dprm;
484 }
485 }
486 break;
487 }
488 if (!ret && !f->fn) { /* Parsed, but do not find fetch method */
489 pr_info("%s type has no corresponding fetch method.\n", t->name);
490 ret = -EINVAL;
491 }
492
493 return ret;
494}
495
496#define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
497
498/* Bitfield type needs to be parsed into a fetch function */
499static int __parse_bitfield_probe_arg(const char *bf,
500 const struct fetch_type *t,
501 struct fetch_param *f)
502{
503 struct bitfield_fetch_param *bprm;
504 unsigned long bw, bo;
505 char *tail;
506
507 if (*bf != 'b')
508 return 0;
509
510 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
511 if (!bprm)
512 return -ENOMEM;
513
514 bprm->orig = *f;
515 f->fn = t->fetch[FETCH_MTD_bitfield];
516 f->data = (void *)bprm;
517 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
518
519 if (bw == 0 || *tail != '@')
520 return -EINVAL;
521
522 bf = tail + 1;
523 bo = simple_strtoul(bf, &tail, 0);
524
525 if (tail == bf || *tail != '/')
526 return -EINVAL;
527
528 bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
529 bprm->low_shift = bprm->hi_shift + bo;
530
531 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
532}
533
534/* String length checking wrapper */
535int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
536 struct probe_arg *parg, bool is_return, bool is_kprobe,
537 const struct fetch_type *ftbl)
538{
539 const char *t;
540 int ret;
541
542 if (strlen(arg) > MAX_ARGSTR_LEN) {
543 pr_info("Argument is too long.: %s\n", arg);
544 return -ENOSPC;
545 }
546 parg->comm = kstrdup(arg, GFP_KERNEL);
547 if (!parg->comm) {
548 pr_info("Failed to allocate memory for command '%s'.\n", arg);
549 return -ENOMEM;
550 }
551 t = strchr(parg->comm, ':');
552 if (t) {
553 arg[t - parg->comm] = '\0';
554 t++;
555 }
556 /*
557 * The default type of $comm should be "string", and it can't be
558 * dereferenced.
559 */
560 if (!t && strcmp(arg, "$comm") == 0)
561 t = "string";
562 parg->type = find_fetch_type(t, ftbl);
563 if (!parg->type) {
564 pr_info("Unsupported type: %s\n", t);
565 return -EINVAL;
566 }
567 parg->offset = *size;
568 *size += parg->type->size;
569 ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return,
570 is_kprobe, ftbl);
571
572 if (ret >= 0 && t != NULL)
573 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
574
575 if (ret >= 0) {
576 parg->fetch_size.fn = get_fetch_size_function(parg->type,
577 parg->fetch.fn,
578 ftbl);
579 parg->fetch_size.data = parg->fetch.data;
580 }
581
582 return ret;
583}
584
585/* Return 1 if name is reserved or already used by another argument */
586int traceprobe_conflict_field_name(const char *name,
587 struct probe_arg *args, int narg)
588{
589 int i;
590
591 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
592 if (strcmp(reserved_field_names[i], name) == 0)
593 return 1;
594
595 for (i = 0; i < narg; i++)
596 if (strcmp(args[i].name, name) == 0)
597 return 1;
598
599 return 0;
600}
601
602void traceprobe_update_arg(struct probe_arg *arg)
603{
604 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
605 update_bitfield_fetch_param(arg->fetch.data);
606 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
607 update_deref_fetch_param(arg->fetch.data);
608 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
609 update_symbol_cache(arg->fetch.data);
610}
611
612void traceprobe_free_probe_arg(struct probe_arg *arg)
613{
614 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
615 free_bitfield_fetch_param(arg->fetch.data);
616 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
617 free_deref_fetch_param(arg->fetch.data);
618 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
619 free_symbol_cache(arg->fetch.data);
620
621 kfree(arg->name);
622 kfree(arg->comm);
623}
624
625int traceprobe_command(const char *buf, int (*createfn)(int, char **))
626{
627 char **argv;
628 int argc, ret;
629
630 argc = 0;
631 ret = 0;
632 argv = argv_split(GFP_KERNEL, buf, &argc);
633 if (!argv)
634 return -ENOMEM;
635
636 if (argc)
637 ret = createfn(argc, argv);
638
639 argv_free(argv);
640
641 return ret;
642}
643
644#define WRITE_BUFSIZE 4096
645
646ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
647 size_t count, loff_t *ppos,
648 int (*createfn)(int, char **))
649{
650 char *kbuf, *tmp;
651 int ret = 0;
652 size_t done = 0;
653 size_t size;
654
655 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
656 if (!kbuf)
657 return -ENOMEM;
658
659 while (done < count) {
660 size = count - done;
661
662 if (size >= WRITE_BUFSIZE)
663 size = WRITE_BUFSIZE - 1;
664
665 if (copy_from_user(kbuf, buffer + done, size)) {
666 ret = -EFAULT;
667 goto out;
668 }
669 kbuf[size] = '\0';
670 tmp = strchr(kbuf, '\n');
671
672 if (tmp) {
673 *tmp = '\0';
674 size = tmp - kbuf + 1;
675 } else if (done + size < count) {
676 pr_warn("Line length is too long: Should be less than %d\n",
677 WRITE_BUFSIZE);
678 ret = -EINVAL;
679 goto out;
680 }
681 done += size;
682 /* Remove comments */
683 tmp = strchr(kbuf, '#');
684
685 if (tmp)
686 *tmp = '\0';
687
688 ret = traceprobe_command(kbuf, createfn);
689 if (ret)
690 goto out;
691 }
692 ret = done;
693
694out:
695 kfree(kbuf);
696
697 return ret;
698}
699
700static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
701 bool is_return)
702{
703 int i;
704 int pos = 0;
705
706 const char *fmt, *arg;
707
708 if (!is_return) {
709 fmt = "(%lx)";
710 arg = "REC->" FIELD_STRING_IP;
711 } else {
712 fmt = "(%lx <- %lx)";
713 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
714 }
715
716 /* When len=0, we just calculate the needed length */
717#define LEN_OR_ZERO (len ? len - pos : 0)
718
719 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
720
721 for (i = 0; i < tp->nr_args; i++) {
722 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
723 tp->args[i].name, tp->args[i].type->fmt);
724 }
725
726 pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
727
728 for (i = 0; i < tp->nr_args; i++) {
729 if (strcmp(tp->args[i].type->name, "string") == 0)
730 pos += snprintf(buf + pos, LEN_OR_ZERO,
731 ", __get_str(%s)",
732 tp->args[i].name);
733 else
734 pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
735 tp->args[i].name);
736 }
737
738#undef LEN_OR_ZERO
739
740 /* return the length of print_fmt */
741 return pos;
742}
743
744int set_print_fmt(struct trace_probe *tp, bool is_return)
745{
746 int len;
747 char *print_fmt;
748
749 /* First: called with 0 length to calculate the needed length */
750 len = __set_print_fmt(tp, NULL, 0, is_return);
751 print_fmt = kmalloc(len + 1, GFP_KERNEL);
752 if (!print_fmt)
753 return -ENOMEM;
754
755 /* Second: actually write the @print_fmt */
756 __set_print_fmt(tp, print_fmt, len + 1, is_return);
757 tp->call.print_fmt = print_fmt;
758
759 return 0;
760}