xref: /openbmc/linux/kernel/trace/trace_probe.c (revision 2aa71b4b) 
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 
16 #include "trace_probe.h"
17 
18 #undef C
19 #define C(a, b)		b
20 
21 static const char *trace_probe_err_text[] = { ERRORS };
22 
23 static const char *reserved_field_names[] = {
24 	"common_type",
25 	"common_flags",
26 	"common_preempt_count",
27 	"common_pid",
28 	"common_tgid",
29 	FIELD_STRING_IP,
30 	FIELD_STRING_RETIP,
31 	FIELD_STRING_FUNC,
32 };
33 
34 /* Printing  in basic type function template */
35 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt)			\
36 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
37 {									\
38 	trace_seq_printf(s, fmt, *(type *)data);			\
39 	return !trace_seq_has_overflowed(s);				\
40 }									\
41 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
42 
43 DEFINE_BASIC_PRINT_TYPE_FUNC(u8,  u8,  "%u")
44 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
45 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
46 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
47 DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  s8,  "%d")
48 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
49 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
50 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
51 DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
52 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
53 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
54 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
55 DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
56 
57 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
58 {
59 	trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
60 	return !trace_seq_has_overflowed(s);
61 }
62 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
63 
64 /* Print type function for string type */
65 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
66 {
67 	int len = *(u32 *)data >> 16;
68 
69 	if (!len)
70 		trace_seq_puts(s, FAULT_STRING);
71 	else
72 		trace_seq_printf(s, "\"%s\"",
73 				 (const char *)get_loc_data(data, ent));
74 	return !trace_seq_has_overflowed(s);
75 }
76 
77 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
78 
79 /* Fetch type information table */
80 static const struct fetch_type probe_fetch_types[] = {
81 	/* Special types */
82 	__ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1,
83 			    "__data_loc char[]"),
84 	__ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
85 			    "__data_loc char[]"),
86 	__ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1,
87 			    "__data_loc char[]"),
88 	/* Basic types */
89 	ASSIGN_FETCH_TYPE(u8,  u8,  0),
90 	ASSIGN_FETCH_TYPE(u16, u16, 0),
91 	ASSIGN_FETCH_TYPE(u32, u32, 0),
92 	ASSIGN_FETCH_TYPE(u64, u64, 0),
93 	ASSIGN_FETCH_TYPE(s8,  u8,  1),
94 	ASSIGN_FETCH_TYPE(s16, u16, 1),
95 	ASSIGN_FETCH_TYPE(s32, u32, 1),
96 	ASSIGN_FETCH_TYPE(s64, u64, 1),
97 	ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
98 	ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
99 	ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
100 	ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
101 	ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8,  0),
102 	ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
103 
104 	ASSIGN_FETCH_TYPE_END
105 };
106 
107 static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
108 {
109 	int i;
110 
111 	/* Reject the symbol/symstr for uprobes */
112 	if (type && (flags & TPARG_FL_USER) &&
113 	    (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
114 		return NULL;
115 
116 	if (!type)
117 		type = DEFAULT_FETCH_TYPE_STR;
118 
119 	/* Special case: bitfield */
120 	if (*type == 'b') {
121 		unsigned long bs;
122 
123 		type = strchr(type, '/');
124 		if (!type)
125 			goto fail;
126 
127 		type++;
128 		if (kstrtoul(type, 0, &bs))
129 			goto fail;
130 
131 		switch (bs) {
132 		case 8:
133 			return find_fetch_type("u8", flags);
134 		case 16:
135 			return find_fetch_type("u16", flags);
136 		case 32:
137 			return find_fetch_type("u32", flags);
138 		case 64:
139 			return find_fetch_type("u64", flags);
140 		default:
141 			goto fail;
142 		}
143 	}
144 
145 	for (i = 0; probe_fetch_types[i].name; i++) {
146 		if (strcmp(type, probe_fetch_types[i].name) == 0)
147 			return &probe_fetch_types[i];
148 	}
149 
150 fail:
151 	return NULL;
152 }
153 
154 static struct trace_probe_log trace_probe_log;
155 
156 void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
157 {
158 	trace_probe_log.subsystem = subsystem;
159 	trace_probe_log.argc = argc;
160 	trace_probe_log.argv = argv;
161 	trace_probe_log.index = 0;
162 }
163 
164 void trace_probe_log_clear(void)
165 {
166 	memset(&trace_probe_log, 0, sizeof(trace_probe_log));
167 }
168 
169 void trace_probe_log_set_index(int index)
170 {
171 	trace_probe_log.index = index;
172 }
173 
174 void __trace_probe_log_err(int offset, int err_type)
175 {
176 	char *command, *p;
177 	int i, len = 0, pos = 0;
178 
179 	if (!trace_probe_log.argv)
180 		return;
181 
182 	/* Recalculate the length and allocate buffer */
183 	for (i = 0; i < trace_probe_log.argc; i++) {
184 		if (i == trace_probe_log.index)
185 			pos = len;
186 		len += strlen(trace_probe_log.argv[i]) + 1;
187 	}
188 	command = kzalloc(len, GFP_KERNEL);
189 	if (!command)
190 		return;
191 
192 	if (trace_probe_log.index >= trace_probe_log.argc) {
193 		/**
194 		 * Set the error position is next to the last arg + space.
195 		 * Note that len includes the terminal null and the cursor
196 		 * appears at pos + 1.
197 		 */
198 		pos = len;
199 		offset = 0;
200 	}
201 
202 	/* And make a command string from argv array */
203 	p = command;
204 	for (i = 0; i < trace_probe_log.argc; i++) {
205 		len = strlen(trace_probe_log.argv[i]);
206 		strcpy(p, trace_probe_log.argv[i]);
207 		p[len] = ' ';
208 		p += len + 1;
209 	}
210 	*(p - 1) = '\0';
211 
212 	tracing_log_err(NULL, trace_probe_log.subsystem, command,
213 			trace_probe_err_text, err_type, pos + offset);
214 
215 	kfree(command);
216 }
217 
218 /* Split symbol and offset. */
219 int traceprobe_split_symbol_offset(char *symbol, long *offset)
220 {
221 	char *tmp;
222 	int ret;
223 
224 	if (!offset)
225 		return -EINVAL;
226 
227 	tmp = strpbrk(symbol, "+-");
228 	if (tmp) {
229 		ret = kstrtol(tmp, 0, offset);
230 		if (ret)
231 			return ret;
232 		*tmp = '\0';
233 	} else
234 		*offset = 0;
235 
236 	return 0;
237 }
238 
239 /* @buf must has MAX_EVENT_NAME_LEN size */
240 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
241 				char *buf, int offset)
242 {
243 	const char *slash, *event = *pevent;
244 	int len;
245 
246 	slash = strchr(event, '/');
247 	if (!slash)
248 		slash = strchr(event, '.');
249 
250 	if (slash) {
251 		if (slash == event) {
252 			trace_probe_log_err(offset, NO_GROUP_NAME);
253 			return -EINVAL;
254 		}
255 		if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
256 			trace_probe_log_err(offset, GROUP_TOO_LONG);
257 			return -EINVAL;
258 		}
259 		strscpy(buf, event, slash - event + 1);
260 		if (!is_good_system_name(buf)) {
261 			trace_probe_log_err(offset, BAD_GROUP_NAME);
262 			return -EINVAL;
263 		}
264 		*pgroup = buf;
265 		*pevent = slash + 1;
266 		offset += slash - event + 1;
267 		event = *pevent;
268 	}
269 	len = strlen(event);
270 	if (len == 0) {
271 		if (slash) {
272 			*pevent = NULL;
273 			return 0;
274 		}
275 		trace_probe_log_err(offset, NO_EVENT_NAME);
276 		return -EINVAL;
277 	} else if (len > MAX_EVENT_NAME_LEN) {
278 		trace_probe_log_err(offset, EVENT_TOO_LONG);
279 		return -EINVAL;
280 	}
281 	if (!is_good_name(event)) {
282 		trace_probe_log_err(offset, BAD_EVENT_NAME);
283 		return -EINVAL;
284 	}
285 	return 0;
286 }
287 
288 static int parse_trace_event_arg(char *arg, struct fetch_insn *code,
289 				 struct traceprobe_parse_context *ctx)
290 {
291 	struct ftrace_event_field *field;
292 	struct list_head *head;
293 
294 	head = trace_get_fields(ctx->event);
295 	list_for_each_entry(field, head, link) {
296 		if (!strcmp(arg, field->name)) {
297 			code->op = FETCH_OP_TP_ARG;
298 			code->data = field;
299 			return 0;
300 		}
301 	}
302 	return -ENOENT;
303 }
304 
305 #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
306 
307 static struct btf *traceprobe_get_btf(void)
308 {
309 	struct btf *btf = bpf_get_btf_vmlinux();
310 
311 	if (IS_ERR_OR_NULL(btf))
312 		return NULL;
313 
314 	return btf;
315 }
316 
317 static u32 btf_type_int(const struct btf_type *t)
318 {
319 	return *(u32 *)(t + 1);
320 }
321 
322 static const char *type_from_btf_id(struct btf *btf, s32 id)
323 {
324 	const struct btf_type *t;
325 	u32 intdata;
326 	s32 tid;
327 
328 	/* TODO: const char * could be converted as a string */
329 	t = btf_type_skip_modifiers(btf, id, &tid);
330 
331 	switch (BTF_INFO_KIND(t->info)) {
332 	case BTF_KIND_ENUM:
333 		/* enum is "int", so convert to "s32" */
334 		return "s32";
335 	case BTF_KIND_ENUM64:
336 		return "s64";
337 	case BTF_KIND_PTR:
338 		/* pointer will be converted to "x??" */
339 		if (IS_ENABLED(CONFIG_64BIT))
340 			return "x64";
341 		else
342 			return "x32";
343 	case BTF_KIND_INT:
344 		intdata = btf_type_int(t);
345 		if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) {
346 			switch (BTF_INT_BITS(intdata)) {
347 			case 8:
348 				return "s8";
349 			case 16:
350 				return "s16";
351 			case 32:
352 				return "s32";
353 			case 64:
354 				return "s64";
355 			}
356 		} else {	/* unsigned */
357 			switch (BTF_INT_BITS(intdata)) {
358 			case 8:
359 				return "u8";
360 			case 16:
361 				return "u16";
362 			case 32:
363 				return "u32";
364 			case 64:
365 				return "u64";
366 			}
367 		}
368 	}
369 	/* TODO: support other types */
370 
371 	return NULL;
372 }
373 
374 static const struct btf_type *find_btf_func_proto(const char *funcname)
375 {
376 	struct btf *btf = traceprobe_get_btf();
377 	const struct btf_type *t;
378 	s32 id;
379 
380 	if (!btf || !funcname)
381 		return ERR_PTR(-EINVAL);
382 
383 	id = btf_find_by_name_kind(btf, funcname, BTF_KIND_FUNC);
384 	if (id <= 0)
385 		return ERR_PTR(-ENOENT);
386 
387 	/* Get BTF_KIND_FUNC type */
388 	t = btf_type_by_id(btf, id);
389 	if (!t || !btf_type_is_func(t))
390 		return ERR_PTR(-ENOENT);
391 
392 	/* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */
393 	t = btf_type_by_id(btf, t->type);
394 	if (!t || !btf_type_is_func_proto(t))
395 		return ERR_PTR(-ENOENT);
396 
397 	return t;
398 }
399 
400 static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr,
401 						   bool tracepoint)
402 {
403 	const struct btf_param *param;
404 	const struct btf_type *t;
405 
406 	if (!funcname || !nr)
407 		return ERR_PTR(-EINVAL);
408 
409 	t = find_btf_func_proto(funcname);
410 	if (IS_ERR(t))
411 		return (const struct btf_param *)t;
412 
413 	*nr = btf_type_vlen(t);
414 	param = (const struct btf_param *)(t + 1);
415 
416 	/* Hide the first 'data' argument of tracepoint */
417 	if (tracepoint) {
418 		(*nr)--;
419 		param++;
420 	}
421 
422 	if (*nr > 0)
423 		return param;
424 	else
425 		return NULL;
426 }
427 
428 static int parse_btf_arg(const char *varname, struct fetch_insn *code,
429 			 struct traceprobe_parse_context *ctx)
430 {
431 	struct btf *btf = traceprobe_get_btf();
432 	const struct btf_param *params;
433 	int i;
434 
435 	if (!btf) {
436 		trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
437 		return -EOPNOTSUPP;
438 	}
439 
440 	if (WARN_ON_ONCE(!ctx->funcname))
441 		return -EINVAL;
442 
443 	if (!ctx->params) {
444 		params = find_btf_func_param(ctx->funcname, &ctx->nr_params,
445 					     ctx->flags & TPARG_FL_TPOINT);
446 		if (IS_ERR_OR_NULL(params)) {
447 			trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
448 			return PTR_ERR(params);
449 		}
450 		ctx->params = params;
451 	} else
452 		params = ctx->params;
453 
454 	for (i = 0; i < ctx->nr_params; i++) {
455 		const char *name = btf_name_by_offset(btf, params[i].name_off);
456 
457 		if (name && !strcmp(name, varname)) {
458 			code->op = FETCH_OP_ARG;
459 			if (ctx->flags & TPARG_FL_TPOINT)
460 				code->param = i + 1;
461 			else
462 				code->param = i;
463 			return 0;
464 		}
465 	}
466 	trace_probe_log_err(ctx->offset, NO_BTFARG);
467 	return -ENOENT;
468 }
469 
470 static const struct fetch_type *parse_btf_arg_type(int arg_idx,
471 					struct traceprobe_parse_context *ctx)
472 {
473 	struct btf *btf = traceprobe_get_btf();
474 	const char *typestr = NULL;
475 
476 	if (btf && ctx->params) {
477 		if (ctx->flags & TPARG_FL_TPOINT)
478 			arg_idx--;
479 		typestr = type_from_btf_id(btf, ctx->params[arg_idx].type);
480 	}
481 
482 	return find_fetch_type(typestr, ctx->flags);
483 }
484 
485 static const struct fetch_type *parse_btf_retval_type(
486 					struct traceprobe_parse_context *ctx)
487 {
488 	struct btf *btf = traceprobe_get_btf();
489 	const char *typestr = NULL;
490 	const struct btf_type *t;
491 
492 	if (btf && ctx->funcname) {
493 		t = find_btf_func_proto(ctx->funcname);
494 		if (!IS_ERR(t))
495 			typestr = type_from_btf_id(btf, t->type);
496 	}
497 
498 	return find_fetch_type(typestr, ctx->flags);
499 }
500 
501 static bool is_btf_retval_void(const char *funcname)
502 {
503 	const struct btf_type *t;
504 
505 	t = find_btf_func_proto(funcname);
506 	if (IS_ERR(t))
507 		return false;
508 
509 	return t->type == 0;
510 }
511 #else
512 static struct btf *traceprobe_get_btf(void)
513 {
514 	return NULL;
515 }
516 
517 static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr,
518 						   bool tracepoint)
519 {
520 	return ERR_PTR(-EOPNOTSUPP);
521 }
522 
523 static int parse_btf_arg(const char *varname, struct fetch_insn *code,
524 			 struct traceprobe_parse_context *ctx)
525 {
526 	trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
527 	return -EOPNOTSUPP;
528 }
529 
530 #define parse_btf_arg_type(idx, ctx)		\
531 	find_fetch_type(NULL, ctx->flags)
532 
533 #define parse_btf_retval_type(ctx)		\
534 	find_fetch_type(NULL, ctx->flags)
535 
536 #define is_btf_retval_void(funcname)	(false)
537 
538 #endif
539 
540 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
541 
542 static int parse_probe_vars(char *arg, const struct fetch_type *t,
543 			    struct fetch_insn *code,
544 			    struct traceprobe_parse_context *ctx)
545 {
546 	unsigned long param;
547 	int err = TP_ERR_BAD_VAR;
548 	int ret = 0;
549 	int len;
550 
551 	if (ctx->flags & TPARG_FL_TEVENT) {
552 		if (code->data)
553 			return -EFAULT;
554 		ret = parse_trace_event_arg(arg, code, ctx);
555 		if (!ret)
556 			return 0;
557 		if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
558 			code->op = FETCH_OP_COMM;
559 			return 0;
560 		}
561 		/* backward compatibility */
562 		ctx->offset = 0;
563 		goto inval;
564 	}
565 
566 	if (strcmp(arg, "retval") == 0) {
567 		if (ctx->flags & TPARG_FL_RETURN) {
568 			if ((ctx->flags & TPARG_FL_KERNEL) &&
569 			    is_btf_retval_void(ctx->funcname)) {
570 				err = TP_ERR_NO_RETVAL;
571 				goto inval;
572 			}
573 			code->op = FETCH_OP_RETVAL;
574 			return 0;
575 		}
576 		err = TP_ERR_RETVAL_ON_PROBE;
577 		goto inval;
578 	}
579 
580 	len = str_has_prefix(arg, "stack");
581 	if (len) {
582 
583 		if (arg[len] == '\0') {
584 			code->op = FETCH_OP_STACKP;
585 			return 0;
586 		}
587 
588 		if (isdigit(arg[len])) {
589 			ret = kstrtoul(arg + len, 10, &param);
590 			if (ret)
591 				goto inval;
592 
593 			if ((ctx->flags & TPARG_FL_KERNEL) &&
594 			    param > PARAM_MAX_STACK) {
595 				err = TP_ERR_BAD_STACK_NUM;
596 				goto inval;
597 			}
598 			code->op = FETCH_OP_STACK;
599 			code->param = (unsigned int)param;
600 			return 0;
601 		}
602 		goto inval;
603 	}
604 
605 	if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
606 		code->op = FETCH_OP_COMM;
607 		return 0;
608 	}
609 
610 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
611 	len = str_has_prefix(arg, "arg");
612 	if (len && tparg_is_function_entry(ctx->flags)) {
613 		ret = kstrtoul(arg + len, 10, &param);
614 		if (ret)
615 			goto inval;
616 
617 		if (!param || param > PARAM_MAX_STACK) {
618 			err = TP_ERR_BAD_ARG_NUM;
619 			goto inval;
620 		}
621 
622 		code->op = FETCH_OP_ARG;
623 		code->param = (unsigned int)param - 1;
624 		/*
625 		 * The tracepoint probe will probe a stub function, and the
626 		 * first parameter of the stub is a dummy and should be ignored.
627 		 */
628 		if (ctx->flags & TPARG_FL_TPOINT)
629 			code->param++;
630 		return 0;
631 	}
632 #endif
633 
634 inval:
635 	__trace_probe_log_err(ctx->offset, err);
636 	return -EINVAL;
637 }
638 
639 static int str_to_immediate(char *str, unsigned long *imm)
640 {
641 	if (isdigit(str[0]))
642 		return kstrtoul(str, 0, imm);
643 	else if (str[0] == '-')
644 		return kstrtol(str, 0, (long *)imm);
645 	else if (str[0] == '+')
646 		return kstrtol(str + 1, 0, (long *)imm);
647 	return -EINVAL;
648 }
649 
650 static int __parse_imm_string(char *str, char **pbuf, int offs)
651 {
652 	size_t len = strlen(str);
653 
654 	if (str[len - 1] != '"') {
655 		trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
656 		return -EINVAL;
657 	}
658 	*pbuf = kstrndup(str, len - 1, GFP_KERNEL);
659 	if (!*pbuf)
660 		return -ENOMEM;
661 	return 0;
662 }
663 
664 /* Recursive argument parser */
665 static int
666 parse_probe_arg(char *arg, const struct fetch_type *type,
667 		struct fetch_insn **pcode, struct fetch_insn *end,
668 		struct traceprobe_parse_context *ctx)
669 {
670 	struct fetch_insn *code = *pcode;
671 	unsigned long param;
672 	int deref = FETCH_OP_DEREF;
673 	long offset = 0;
674 	char *tmp;
675 	int ret = 0;
676 
677 	switch (arg[0]) {
678 	case '$':
679 		ret = parse_probe_vars(arg + 1, type, code, ctx);
680 		break;
681 
682 	case '%':	/* named register */
683 		if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
684 			/* eprobe and fprobe do not handle registers */
685 			trace_probe_log_err(ctx->offset, BAD_VAR);
686 			break;
687 		}
688 		ret = regs_query_register_offset(arg + 1);
689 		if (ret >= 0) {
690 			code->op = FETCH_OP_REG;
691 			code->param = (unsigned int)ret;
692 			ret = 0;
693 		} else
694 			trace_probe_log_err(ctx->offset, BAD_REG_NAME);
695 		break;
696 
697 	case '@':	/* memory, file-offset or symbol */
698 		if (isdigit(arg[1])) {
699 			ret = kstrtoul(arg + 1, 0, &param);
700 			if (ret) {
701 				trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
702 				break;
703 			}
704 			/* load address */
705 			code->op = FETCH_OP_IMM;
706 			code->immediate = param;
707 		} else if (arg[1] == '+') {
708 			/* kprobes don't support file offsets */
709 			if (ctx->flags & TPARG_FL_KERNEL) {
710 				trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
711 				return -EINVAL;
712 			}
713 			ret = kstrtol(arg + 2, 0, &offset);
714 			if (ret) {
715 				trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
716 				break;
717 			}
718 
719 			code->op = FETCH_OP_FOFFS;
720 			code->immediate = (unsigned long)offset;  // imm64?
721 		} else {
722 			/* uprobes don't support symbols */
723 			if (!(ctx->flags & TPARG_FL_KERNEL)) {
724 				trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
725 				return -EINVAL;
726 			}
727 			/* Preserve symbol for updating */
728 			code->op = FETCH_NOP_SYMBOL;
729 			code->data = kstrdup(arg + 1, GFP_KERNEL);
730 			if (!code->data)
731 				return -ENOMEM;
732 			if (++code == end) {
733 				trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
734 				return -EINVAL;
735 			}
736 			code->op = FETCH_OP_IMM;
737 			code->immediate = 0;
738 		}
739 		/* These are fetching from memory */
740 		if (++code == end) {
741 			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
742 			return -EINVAL;
743 		}
744 		*pcode = code;
745 		code->op = FETCH_OP_DEREF;
746 		code->offset = offset;
747 		break;
748 
749 	case '+':	/* deref memory */
750 	case '-':
751 		if (arg[1] == 'u') {
752 			deref = FETCH_OP_UDEREF;
753 			arg[1] = arg[0];
754 			arg++;
755 		}
756 		if (arg[0] == '+')
757 			arg++;	/* Skip '+', because kstrtol() rejects it. */
758 		tmp = strchr(arg, '(');
759 		if (!tmp) {
760 			trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
761 			return -EINVAL;
762 		}
763 		*tmp = '\0';
764 		ret = kstrtol(arg, 0, &offset);
765 		if (ret) {
766 			trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
767 			break;
768 		}
769 		ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
770 		arg = tmp + 1;
771 		tmp = strrchr(arg, ')');
772 		if (!tmp) {
773 			trace_probe_log_err(ctx->offset + strlen(arg),
774 					    DEREF_OPEN_BRACE);
775 			return -EINVAL;
776 		} else {
777 			const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags);
778 			int cur_offs = ctx->offset;
779 
780 			*tmp = '\0';
781 			ret = parse_probe_arg(arg, t2, &code, end, ctx);
782 			if (ret)
783 				break;
784 			ctx->offset = cur_offs;
785 			if (code->op == FETCH_OP_COMM ||
786 			    code->op == FETCH_OP_DATA) {
787 				trace_probe_log_err(ctx->offset, COMM_CANT_DEREF);
788 				return -EINVAL;
789 			}
790 			if (++code == end) {
791 				trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
792 				return -EINVAL;
793 			}
794 			*pcode = code;
795 
796 			code->op = deref;
797 			code->offset = offset;
798 		}
799 		break;
800 	case '\\':	/* Immediate value */
801 		if (arg[1] == '"') {	/* Immediate string */
802 			ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
803 			if (ret)
804 				break;
805 			code->op = FETCH_OP_DATA;
806 			code->data = tmp;
807 		} else {
808 			ret = str_to_immediate(arg + 1, &code->immediate);
809 			if (ret)
810 				trace_probe_log_err(ctx->offset + 1, BAD_IMM);
811 			else
812 				code->op = FETCH_OP_IMM;
813 		}
814 		break;
815 	default:
816 		if (isalpha(arg[0]) || arg[0] == '_') {	/* BTF variable */
817 			if (!tparg_is_function_entry(ctx->flags)) {
818 				trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
819 				return -EINVAL;
820 			}
821 			ret = parse_btf_arg(arg, code, ctx);
822 			break;
823 		}
824 	}
825 	if (!ret && code->op == FETCH_OP_NOP) {
826 		/* Parsed, but do not find fetch method */
827 		trace_probe_log_err(ctx->offset, BAD_FETCH_ARG);
828 		ret = -EINVAL;
829 	}
830 	return ret;
831 }
832 
833 #define BYTES_TO_BITS(nb)	((BITS_PER_LONG * (nb)) / sizeof(long))
834 
835 /* Bitfield type needs to be parsed into a fetch function */
836 static int __parse_bitfield_probe_arg(const char *bf,
837 				      const struct fetch_type *t,
838 				      struct fetch_insn **pcode)
839 {
840 	struct fetch_insn *code = *pcode;
841 	unsigned long bw, bo;
842 	char *tail;
843 
844 	if (*bf != 'b')
845 		return 0;
846 
847 	bw = simple_strtoul(bf + 1, &tail, 0);	/* Use simple one */
848 
849 	if (bw == 0 || *tail != '@')
850 		return -EINVAL;
851 
852 	bf = tail + 1;
853 	bo = simple_strtoul(bf, &tail, 0);
854 
855 	if (tail == bf || *tail != '/')
856 		return -EINVAL;
857 	code++;
858 	if (code->op != FETCH_OP_NOP)
859 		return -EINVAL;
860 	*pcode = code;
861 
862 	code->op = FETCH_OP_MOD_BF;
863 	code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
864 	code->rshift = BYTES_TO_BITS(t->size) - bw;
865 	code->basesize = t->size;
866 
867 	return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
868 }
869 
870 /* String length checking wrapper */
871 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
872 					   struct probe_arg *parg,
873 					   struct traceprobe_parse_context *ctx)
874 {
875 	struct fetch_insn *code, *scode, *tmp = NULL;
876 	char *t, *t2, *t3;
877 	int ret, len;
878 	char *arg;
879 
880 	arg = kstrdup(argv, GFP_KERNEL);
881 	if (!arg)
882 		return -ENOMEM;
883 
884 	ret = -EINVAL;
885 	len = strlen(arg);
886 	if (len > MAX_ARGSTR_LEN) {
887 		trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
888 		goto out;
889 	} else if (len == 0) {
890 		trace_probe_log_err(ctx->offset, NO_ARG_BODY);
891 		goto out;
892 	}
893 
894 	ret = -ENOMEM;
895 	parg->comm = kstrdup(arg, GFP_KERNEL);
896 	if (!parg->comm)
897 		goto out;
898 
899 	ret = -EINVAL;
900 	t = strchr(arg, ':');
901 	if (t) {
902 		*t = '\0';
903 		t2 = strchr(++t, '[');
904 		if (t2) {
905 			*t2++ = '\0';
906 			t3 = strchr(t2, ']');
907 			if (!t3) {
908 				int offs = t2 + strlen(t2) - arg;
909 
910 				trace_probe_log_err(ctx->offset + offs,
911 						    ARRAY_NO_CLOSE);
912 				goto out;
913 			} else if (t3[1] != '\0') {
914 				trace_probe_log_err(ctx->offset + t3 + 1 - arg,
915 						    BAD_ARRAY_SUFFIX);
916 				goto out;
917 			}
918 			*t3 = '\0';
919 			if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
920 				trace_probe_log_err(ctx->offset + t2 - arg,
921 						    BAD_ARRAY_NUM);
922 				goto out;
923 			}
924 			if (parg->count > MAX_ARRAY_LEN) {
925 				trace_probe_log_err(ctx->offset + t2 - arg,
926 						    ARRAY_TOO_BIG);
927 				goto out;
928 			}
929 		}
930 	}
931 
932 	/*
933 	 * Since $comm and immediate string can not be dereferenced,
934 	 * we can find those by strcmp. But ignore for eprobes.
935 	 */
936 	if (!(ctx->flags & TPARG_FL_TEVENT) &&
937 	    (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
938 	     strncmp(arg, "\\\"", 2) == 0)) {
939 		/* The type of $comm must be "string", and not an array. */
940 		if (parg->count || (t && strcmp(t, "string")))
941 			goto out;
942 		parg->type = find_fetch_type("string", ctx->flags);
943 	} else
944 		parg->type = find_fetch_type(t, ctx->flags);
945 	if (!parg->type) {
946 		trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0), BAD_TYPE);
947 		goto out;
948 	}
949 	parg->offset = *size;
950 	*size += parg->type->size * (parg->count ?: 1);
951 
952 	ret = -ENOMEM;
953 	if (parg->count) {
954 		len = strlen(parg->type->fmttype) + 6;
955 		parg->fmt = kmalloc(len, GFP_KERNEL);
956 		if (!parg->fmt)
957 			goto out;
958 		snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
959 			 parg->count);
960 	}
961 
962 	code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
963 	if (!code)
964 		goto out;
965 	code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
966 
967 	ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
968 			      ctx);
969 	if (ret)
970 		goto fail;
971 
972 	/* Update storing type if BTF is available */
973 	if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) && !t) {
974 		if (code->op == FETCH_OP_ARG)
975 			parg->type = parse_btf_arg_type(code->param, ctx);
976 		else if (code->op == FETCH_OP_RETVAL)
977 			parg->type = parse_btf_retval_type(ctx);
978 	}
979 
980 	ret = -EINVAL;
981 	/* Store operation */
982 	if (parg->type->is_string) {
983 		if (!strcmp(parg->type->name, "symstr")) {
984 			if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
985 			    code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
986 			    code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
987 				trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
988 						    BAD_SYMSTRING);
989 				goto fail;
990 			}
991 		} else {
992 			if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
993 			    code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
994 			    code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
995 				trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
996 						    BAD_STRING);
997 				goto fail;
998 			}
999 		}
1000 		if (!strcmp(parg->type->name, "symstr") ||
1001 		    (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
1002 		     code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
1003 		     parg->count) {
1004 			/*
1005 			 * IMM, DATA and COMM is pointing actual address, those
1006 			 * must be kept, and if parg->count != 0, this is an
1007 			 * array of string pointers instead of string address
1008 			 * itself.
1009 			 * For the symstr, it doesn't need to dereference, thus
1010 			 * it just get the value.
1011 			 */
1012 			code++;
1013 			if (code->op != FETCH_OP_NOP) {
1014 				trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1015 				goto fail;
1016 			}
1017 		}
1018 		/* If op == DEREF, replace it with STRING */
1019 		if (!strcmp(parg->type->name, "ustring") ||
1020 		    code->op == FETCH_OP_UDEREF)
1021 			code->op = FETCH_OP_ST_USTRING;
1022 		else if (!strcmp(parg->type->name, "symstr"))
1023 			code->op = FETCH_OP_ST_SYMSTR;
1024 		else
1025 			code->op = FETCH_OP_ST_STRING;
1026 		code->size = parg->type->size;
1027 		parg->dynamic = true;
1028 	} else if (code->op == FETCH_OP_DEREF) {
1029 		code->op = FETCH_OP_ST_MEM;
1030 		code->size = parg->type->size;
1031 	} else if (code->op == FETCH_OP_UDEREF) {
1032 		code->op = FETCH_OP_ST_UMEM;
1033 		code->size = parg->type->size;
1034 	} else {
1035 		code++;
1036 		if (code->op != FETCH_OP_NOP) {
1037 			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1038 			goto fail;
1039 		}
1040 		code->op = FETCH_OP_ST_RAW;
1041 		code->size = parg->type->size;
1042 	}
1043 	scode = code;
1044 	/* Modify operation */
1045 	if (t != NULL) {
1046 		ret = __parse_bitfield_probe_arg(t, parg->type, &code);
1047 		if (ret) {
1048 			trace_probe_log_err(ctx->offset + t - arg, BAD_BITFIELD);
1049 			goto fail;
1050 		}
1051 	}
1052 	ret = -EINVAL;
1053 	/* Loop(Array) operation */
1054 	if (parg->count) {
1055 		if (scode->op != FETCH_OP_ST_MEM &&
1056 		    scode->op != FETCH_OP_ST_STRING &&
1057 		    scode->op != FETCH_OP_ST_USTRING) {
1058 			trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
1059 					    BAD_STRING);
1060 			goto fail;
1061 		}
1062 		code++;
1063 		if (code->op != FETCH_OP_NOP) {
1064 			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1065 			goto fail;
1066 		}
1067 		code->op = FETCH_OP_LP_ARRAY;
1068 		code->param = parg->count;
1069 	}
1070 	code++;
1071 	code->op = FETCH_OP_END;
1072 
1073 	ret = 0;
1074 	/* Shrink down the code buffer */
1075 	parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
1076 	if (!parg->code)
1077 		ret = -ENOMEM;
1078 	else
1079 		memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
1080 
1081 fail:
1082 	if (ret) {
1083 		for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
1084 			if (code->op == FETCH_NOP_SYMBOL ||
1085 			    code->op == FETCH_OP_DATA)
1086 				kfree(code->data);
1087 	}
1088 	kfree(tmp);
1089 out:
1090 	kfree(arg);
1091 
1092 	return ret;
1093 }
1094 
1095 /* Return 1 if name is reserved or already used by another argument */
1096 static int traceprobe_conflict_field_name(const char *name,
1097 					  struct probe_arg *args, int narg)
1098 {
1099 	int i;
1100 
1101 	for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1102 		if (strcmp(reserved_field_names[i], name) == 0)
1103 			return 1;
1104 
1105 	for (i = 0; i < narg; i++)
1106 		if (strcmp(args[i].name, name) == 0)
1107 			return 1;
1108 
1109 	return 0;
1110 }
1111 
1112 static char *generate_probe_arg_name(const char *arg, int idx)
1113 {
1114 	char *name = NULL;
1115 	const char *end;
1116 
1117 	/*
1118 	 * If argument name is omitted, try arg as a name (BTF variable)
1119 	 * or "argN".
1120 	 */
1121 	if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
1122 		end = strchr(arg, ':');
1123 		if (!end)
1124 			end = arg + strlen(arg);
1125 
1126 		name = kmemdup_nul(arg, end - arg, GFP_KERNEL);
1127 		if (!name || !is_good_name(name)) {
1128 			kfree(name);
1129 			name = NULL;
1130 		}
1131 	}
1132 
1133 	if (!name)
1134 		name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
1135 
1136 	return name;
1137 }
1138 
1139 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
1140 			       struct traceprobe_parse_context *ctx)
1141 {
1142 	struct probe_arg *parg = &tp->args[i];
1143 	const char *body;
1144 
1145 	/* Increment count for freeing args in error case */
1146 	tp->nr_args++;
1147 
1148 	body = strchr(arg, '=');
1149 	if (body) {
1150 		if (body - arg > MAX_ARG_NAME_LEN) {
1151 			trace_probe_log_err(0, ARG_NAME_TOO_LONG);
1152 			return -EINVAL;
1153 		} else if (body == arg) {
1154 			trace_probe_log_err(0, NO_ARG_NAME);
1155 			return -EINVAL;
1156 		}
1157 		parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
1158 		body++;
1159 	} else {
1160 		parg->name = generate_probe_arg_name(arg, i);
1161 		body = arg;
1162 	}
1163 	if (!parg->name)
1164 		return -ENOMEM;
1165 
1166 	if (!is_good_name(parg->name)) {
1167 		trace_probe_log_err(0, BAD_ARG_NAME);
1168 		return -EINVAL;
1169 	}
1170 	if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
1171 		trace_probe_log_err(0, USED_ARG_NAME);
1172 		return -EINVAL;
1173 	}
1174 	ctx->offset = body - arg;
1175 	/* Parse fetch argument */
1176 	return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);
1177 }
1178 
1179 void traceprobe_free_probe_arg(struct probe_arg *arg)
1180 {
1181 	struct fetch_insn *code = arg->code;
1182 
1183 	while (code && code->op != FETCH_OP_END) {
1184 		if (code->op == FETCH_NOP_SYMBOL ||
1185 		    code->op == FETCH_OP_DATA)
1186 			kfree(code->data);
1187 		code++;
1188 	}
1189 	kfree(arg->code);
1190 	kfree(arg->name);
1191 	kfree(arg->comm);
1192 	kfree(arg->fmt);
1193 }
1194 
1195 static int argv_has_var_arg(int argc, const char *argv[], int *args_idx,
1196 			    struct traceprobe_parse_context *ctx)
1197 {
1198 	int i, found = 0;
1199 
1200 	for (i = 0; i < argc; i++)
1201 		if (str_has_prefix(argv[i], "$arg")) {
1202 			trace_probe_log_set_index(i + 2);
1203 
1204 			if (!tparg_is_function_entry(ctx->flags)) {
1205 				trace_probe_log_err(0, NOFENTRY_ARGS);
1206 				return -EINVAL;
1207 			}
1208 
1209 			if (isdigit(argv[i][4])) {
1210 				found = 1;
1211 				continue;
1212 			}
1213 
1214 			if (argv[i][4] != '*') {
1215 				trace_probe_log_err(0, BAD_VAR);
1216 				return -EINVAL;
1217 			}
1218 
1219 			if (*args_idx >= 0 && *args_idx < argc) {
1220 				trace_probe_log_err(0, DOUBLE_ARGS);
1221 				return -EINVAL;
1222 			}
1223 			found = 1;
1224 			*args_idx = i;
1225 		}
1226 
1227 	return found;
1228 }
1229 
1230 static int sprint_nth_btf_arg(int idx, const char *type,
1231 			      char *buf, int bufsize,
1232 			      struct traceprobe_parse_context *ctx)
1233 {
1234 	struct btf *btf = traceprobe_get_btf();
1235 	const char *name;
1236 	int ret;
1237 
1238 	if (idx >= ctx->nr_params) {
1239 		trace_probe_log_err(0, NO_BTFARG);
1240 		return -ENOENT;
1241 	}
1242 	name = btf_name_by_offset(btf, ctx->params[idx].name_off);
1243 	if (!name) {
1244 		trace_probe_log_err(0, NO_BTF_ENTRY);
1245 		return -ENOENT;
1246 	}
1247 	ret = snprintf(buf, bufsize, "%s%s", name, type);
1248 	if (ret >= bufsize) {
1249 		trace_probe_log_err(0, ARGS_2LONG);
1250 		return -E2BIG;
1251 	}
1252 	return ret;
1253 }
1254 
1255 /* Return new_argv which must be freed after use */
1256 const char **traceprobe_expand_meta_args(int argc, const char *argv[],
1257 					 int *new_argc, char *buf, int bufsize,
1258 					 struct traceprobe_parse_context *ctx)
1259 {
1260 	const struct btf_param *params = NULL;
1261 	int i, j, n, used, ret, args_idx = -1;
1262 	const char **new_argv = NULL;
1263 	int nr_params;
1264 
1265 	ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
1266 	if (ret < 0)
1267 		return ERR_PTR(ret);
1268 
1269 	if (!ret) {
1270 		*new_argc = argc;
1271 		return NULL;
1272 	}
1273 
1274 	params = find_btf_func_param(ctx->funcname, &nr_params,
1275 				     ctx->flags & TPARG_FL_TPOINT);
1276 	if (IS_ERR_OR_NULL(params)) {
1277 		if (args_idx != -1) {
1278 			/* $arg* requires BTF info */
1279 			trace_probe_log_err(0, NOSUP_BTFARG);
1280 			return (const char **)params;
1281 		}
1282 		*new_argc = argc;
1283 		return NULL;
1284 	}
1285 	ctx->params = params;
1286 	ctx->nr_params = nr_params;
1287 
1288 	if (args_idx >= 0)
1289 		*new_argc = argc + ctx->nr_params - 1;
1290 	else
1291 		*new_argc = argc;
1292 
1293 	new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL);
1294 	if (!new_argv)
1295 		return ERR_PTR(-ENOMEM);
1296 
1297 	used = 0;
1298 	for (i = 0, j = 0; i < argc; i++) {
1299 		trace_probe_log_set_index(i + 2);
1300 		if (i == args_idx) {
1301 			for (n = 0; n < nr_params; n++) {
1302 				ret = sprint_nth_btf_arg(n, "", buf + used,
1303 							 bufsize - used, ctx);
1304 				if (ret < 0)
1305 					goto error;
1306 
1307 				new_argv[j++] = buf + used;
1308 				used += ret + 1;
1309 			}
1310 			continue;
1311 		}
1312 
1313 		if (str_has_prefix(argv[i], "$arg")) {
1314 			char *type = NULL;
1315 
1316 			n = simple_strtoul(argv[i] + 4, &type, 10);
1317 			if (type && !(*type == ':' || *type == '\0')) {
1318 				trace_probe_log_err(0, BAD_VAR);
1319 				ret = -ENOENT;
1320 				goto error;
1321 			}
1322 			/* Note: $argN starts from $arg1 */
1323 			ret = sprint_nth_btf_arg(n - 1, type, buf + used,
1324 						 bufsize - used, ctx);
1325 			if (ret < 0)
1326 				goto error;
1327 			new_argv[j++] = buf + used;
1328 			used += ret + 1;
1329 		} else
1330 			new_argv[j++] = argv[i];
1331 	}
1332 
1333 	return new_argv;
1334 
1335 error:
1336 	kfree(new_argv);
1337 	return ERR_PTR(ret);
1338 }
1339 
1340 int traceprobe_update_arg(struct probe_arg *arg)
1341 {
1342 	struct fetch_insn *code = arg->code;
1343 	long offset;
1344 	char *tmp;
1345 	char c;
1346 	int ret = 0;
1347 
1348 	while (code && code->op != FETCH_OP_END) {
1349 		if (code->op == FETCH_NOP_SYMBOL) {
1350 			if (code[1].op != FETCH_OP_IMM)
1351 				return -EINVAL;
1352 
1353 			tmp = strpbrk(code->data, "+-");
1354 			if (tmp)
1355 				c = *tmp;
1356 			ret = traceprobe_split_symbol_offset(code->data,
1357 							     &offset);
1358 			if (ret)
1359 				return ret;
1360 
1361 			code[1].immediate =
1362 				(unsigned long)kallsyms_lookup_name(code->data);
1363 			if (tmp)
1364 				*tmp = c;
1365 			if (!code[1].immediate)
1366 				return -ENOENT;
1367 			code[1].immediate += offset;
1368 		}
1369 		code++;
1370 	}
1371 	return 0;
1372 }
1373 
1374 /* When len=0, we just calculate the needed length */
1375 #define LEN_OR_ZERO (len ? len - pos : 0)
1376 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
1377 			   enum probe_print_type ptype)
1378 {
1379 	struct probe_arg *parg;
1380 	int i, j;
1381 	int pos = 0;
1382 	const char *fmt, *arg;
1383 
1384 	switch (ptype) {
1385 	case PROBE_PRINT_NORMAL:
1386 		fmt = "(%lx)";
1387 		arg = ", REC->" FIELD_STRING_IP;
1388 		break;
1389 	case PROBE_PRINT_RETURN:
1390 		fmt = "(%lx <- %lx)";
1391 		arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1392 		break;
1393 	case PROBE_PRINT_EVENT:
1394 		fmt = "";
1395 		arg = "";
1396 		break;
1397 	default:
1398 		WARN_ON_ONCE(1);
1399 		return 0;
1400 	}
1401 
1402 	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1403 
1404 	for (i = 0; i < tp->nr_args; i++) {
1405 		parg = tp->args + i;
1406 		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
1407 		if (parg->count) {
1408 			pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
1409 					parg->type->fmt);
1410 			for (j = 1; j < parg->count; j++)
1411 				pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
1412 						parg->type->fmt);
1413 			pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
1414 		} else
1415 			pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
1416 					parg->type->fmt);
1417 	}
1418 
1419 	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
1420 
1421 	for (i = 0; i < tp->nr_args; i++) {
1422 		parg = tp->args + i;
1423 		if (parg->count) {
1424 			if (parg->type->is_string)
1425 				fmt = ", __get_str(%s[%d])";
1426 			else
1427 				fmt = ", REC->%s[%d]";
1428 			for (j = 0; j < parg->count; j++)
1429 				pos += snprintf(buf + pos, LEN_OR_ZERO,
1430 						fmt, parg->name, j);
1431 		} else {
1432 			if (parg->type->is_string)
1433 				fmt = ", __get_str(%s)";
1434 			else
1435 				fmt = ", REC->%s";
1436 			pos += snprintf(buf + pos, LEN_OR_ZERO,
1437 					fmt, parg->name);
1438 		}
1439 	}
1440 
1441 	/* return the length of print_fmt */
1442 	return pos;
1443 }
1444 #undef LEN_OR_ZERO
1445 
1446 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
1447 {
1448 	struct trace_event_call *call = trace_probe_event_call(tp);
1449 	int len;
1450 	char *print_fmt;
1451 
1452 	/* First: called with 0 length to calculate the needed length */
1453 	len = __set_print_fmt(tp, NULL, 0, ptype);
1454 	print_fmt = kmalloc(len + 1, GFP_KERNEL);
1455 	if (!print_fmt)
1456 		return -ENOMEM;
1457 
1458 	/* Second: actually write the @print_fmt */
1459 	__set_print_fmt(tp, print_fmt, len + 1, ptype);
1460 	call->print_fmt = print_fmt;
1461 
1462 	return 0;
1463 }
1464 
1465 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
1466 				 size_t offset, struct trace_probe *tp)
1467 {
1468 	int ret, i;
1469 
1470 	/* Set argument names as fields */
1471 	for (i = 0; i < tp->nr_args; i++) {
1472 		struct probe_arg *parg = &tp->args[i];
1473 		const char *fmt = parg->type->fmttype;
1474 		int size = parg->type->size;
1475 
1476 		if (parg->fmt)
1477 			fmt = parg->fmt;
1478 		if (parg->count)
1479 			size *= parg->count;
1480 		ret = trace_define_field(event_call, fmt, parg->name,
1481 					 offset + parg->offset, size,
1482 					 parg->type->is_signed,
1483 					 FILTER_OTHER);
1484 		if (ret)
1485 			return ret;
1486 	}
1487 	return 0;
1488 }
1489 
1490 static void trace_probe_event_free(struct trace_probe_event *tpe)
1491 {
1492 	kfree(tpe->class.system);
1493 	kfree(tpe->call.name);
1494 	kfree(tpe->call.print_fmt);
1495 	kfree(tpe);
1496 }
1497 
1498 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
1499 {
1500 	if (trace_probe_has_sibling(tp))
1501 		return -EBUSY;
1502 
1503 	list_del_init(&tp->list);
1504 	trace_probe_event_free(tp->event);
1505 
1506 	tp->event = to->event;
1507 	list_add_tail(&tp->list, trace_probe_probe_list(to));
1508 
1509 	return 0;
1510 }
1511 
1512 void trace_probe_unlink(struct trace_probe *tp)
1513 {
1514 	list_del_init(&tp->list);
1515 	if (list_empty(trace_probe_probe_list(tp)))
1516 		trace_probe_event_free(tp->event);
1517 	tp->event = NULL;
1518 }
1519 
1520 void trace_probe_cleanup(struct trace_probe *tp)
1521 {
1522 	int i;
1523 
1524 	for (i = 0; i < tp->nr_args; i++)
1525 		traceprobe_free_probe_arg(&tp->args[i]);
1526 
1527 	if (tp->event)
1528 		trace_probe_unlink(tp);
1529 }
1530 
1531 int trace_probe_init(struct trace_probe *tp, const char *event,
1532 		     const char *group, bool alloc_filter)
1533 {
1534 	struct trace_event_call *call;
1535 	size_t size = sizeof(struct trace_probe_event);
1536 	int ret = 0;
1537 
1538 	if (!event || !group)
1539 		return -EINVAL;
1540 
1541 	if (alloc_filter)
1542 		size += sizeof(struct trace_uprobe_filter);
1543 
1544 	tp->event = kzalloc(size, GFP_KERNEL);
1545 	if (!tp->event)
1546 		return -ENOMEM;
1547 
1548 	INIT_LIST_HEAD(&tp->event->files);
1549 	INIT_LIST_HEAD(&tp->event->class.fields);
1550 	INIT_LIST_HEAD(&tp->event->probes);
1551 	INIT_LIST_HEAD(&tp->list);
1552 	list_add(&tp->list, &tp->event->probes);
1553 
1554 	call = trace_probe_event_call(tp);
1555 	call->class = &tp->event->class;
1556 	call->name = kstrdup(event, GFP_KERNEL);
1557 	if (!call->name) {
1558 		ret = -ENOMEM;
1559 		goto error;
1560 	}
1561 
1562 	tp->event->class.system = kstrdup(group, GFP_KERNEL);
1563 	if (!tp->event->class.system) {
1564 		ret = -ENOMEM;
1565 		goto error;
1566 	}
1567 
1568 	return 0;
1569 
1570 error:
1571 	trace_probe_cleanup(tp);
1572 	return ret;
1573 }
1574 
1575 static struct trace_event_call *
1576 find_trace_event_call(const char *system, const char *event_name)
1577 {
1578 	struct trace_event_call *tp_event;
1579 	const char *name;
1580 
1581 	list_for_each_entry(tp_event, &ftrace_events, list) {
1582 		if (!tp_event->class->system ||
1583 		    strcmp(system, tp_event->class->system))
1584 			continue;
1585 		name = trace_event_name(tp_event);
1586 		if (!name || strcmp(event_name, name))
1587 			continue;
1588 		return tp_event;
1589 	}
1590 
1591 	return NULL;
1592 }
1593 
1594 int trace_probe_register_event_call(struct trace_probe *tp)
1595 {
1596 	struct trace_event_call *call = trace_probe_event_call(tp);
1597 	int ret;
1598 
1599 	lockdep_assert_held(&event_mutex);
1600 
1601 	if (find_trace_event_call(trace_probe_group_name(tp),
1602 				  trace_probe_name(tp)))
1603 		return -EEXIST;
1604 
1605 	ret = register_trace_event(&call->event);
1606 	if (!ret)
1607 		return -ENODEV;
1608 
1609 	ret = trace_add_event_call(call);
1610 	if (ret)
1611 		unregister_trace_event(&call->event);
1612 
1613 	return ret;
1614 }
1615 
1616 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
1617 {
1618 	struct event_file_link *link;
1619 
1620 	link = kmalloc(sizeof(*link), GFP_KERNEL);
1621 	if (!link)
1622 		return -ENOMEM;
1623 
1624 	link->file = file;
1625 	INIT_LIST_HEAD(&link->list);
1626 	list_add_tail_rcu(&link->list, &tp->event->files);
1627 	trace_probe_set_flag(tp, TP_FLAG_TRACE);
1628 	return 0;
1629 }
1630 
1631 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
1632 						  struct trace_event_file *file)
1633 {
1634 	struct event_file_link *link;
1635 
1636 	trace_probe_for_each_link(link, tp) {
1637 		if (link->file == file)
1638 			return link;
1639 	}
1640 
1641 	return NULL;
1642 }
1643 
1644 int trace_probe_remove_file(struct trace_probe *tp,
1645 			    struct trace_event_file *file)
1646 {
1647 	struct event_file_link *link;
1648 
1649 	link = trace_probe_get_file_link(tp, file);
1650 	if (!link)
1651 		return -ENOENT;
1652 
1653 	list_del_rcu(&link->list);
1654 	kvfree_rcu_mightsleep(link);
1655 
1656 	if (list_empty(&tp->event->files))
1657 		trace_probe_clear_flag(tp, TP_FLAG_TRACE);
1658 
1659 	return 0;
1660 }
1661 
1662 /*
1663  * Return the smallest index of different type argument (start from 1).
1664  * If all argument types and name are same, return 0.
1665  */
1666 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
1667 {
1668 	int i;
1669 
1670 	/* In case of more arguments */
1671 	if (a->nr_args < b->nr_args)
1672 		return a->nr_args + 1;
1673 	if (a->nr_args > b->nr_args)
1674 		return b->nr_args + 1;
1675 
1676 	for (i = 0; i < a->nr_args; i++) {
1677 		if ((b->nr_args <= i) ||
1678 		    ((a->args[i].type != b->args[i].type) ||
1679 		     (a->args[i].count != b->args[i].count) ||
1680 		     strcmp(a->args[i].name, b->args[i].name)))
1681 			return i + 1;
1682 	}
1683 
1684 	return 0;
1685 }
1686 
1687 bool trace_probe_match_command_args(struct trace_probe *tp,
1688 				    int argc, const char **argv)
1689 {
1690 	char buf[MAX_ARGSTR_LEN + 1];
1691 	int i;
1692 
1693 	if (tp->nr_args < argc)
1694 		return false;
1695 
1696 	for (i = 0; i < argc; i++) {
1697 		snprintf(buf, sizeof(buf), "%s=%s",
1698 			 tp->args[i].name, tp->args[i].comm);
1699 		if (strcmp(buf, argv[i]))
1700 			return false;
1701 	}
1702 	return true;
1703 }
1704 
1705 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
1706 {
1707 	int argc = 0, ret = 0;
1708 	char **argv;
1709 
1710 	argv = argv_split(GFP_KERNEL, raw_command, &argc);
1711 	if (!argv)
1712 		return -ENOMEM;
1713 
1714 	if (argc)
1715 		ret = createfn(argc, (const char **)argv);
1716 
1717 	argv_free(argv);
1718 
1719 	return ret;
1720 }
1721 
1722 int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
1723 		 u8 *data, void *field)
1724 {
1725 	void *p;
1726 	int i, j;
1727 
1728 	for (i = 0; i < nr_args; i++) {
1729 		struct probe_arg *a = args + i;
1730 
1731 		trace_seq_printf(s, " %s=", a->name);
1732 		if (likely(!a->count)) {
1733 			if (!a->type->print(s, data + a->offset, field))
1734 				return -ENOMEM;
1735 			continue;
1736 		}
1737 		trace_seq_putc(s, '{');
1738 		p = data + a->offset;
1739 		for (j = 0; j < a->count; j++) {
1740 			if (!a->type->print(s, p, field))
1741 				return -ENOMEM;
1742 			trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
1743 			p += a->type->size;
1744 		}
1745 	}
1746 	return 0;
1747 }
1748