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 <linux/fs.h>
16#include "trace_btf.h"
17
18#include "trace_probe.h"
19
20#undef C
21#define C(a, b)		b
22
23static const char *trace_probe_err_text[] = { ERRORS };
24
25static const char *reserved_field_names[] = {
26	"common_type",
27	"common_flags",
28	"common_preempt_count",
29	"common_pid",
30	"common_tgid",
31	FIELD_STRING_IP,
32	FIELD_STRING_RETIP,
33	FIELD_STRING_FUNC,
34};
35
36/* Printing  in basic type function template */
37#define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt)			\
38int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
39{									\
40	trace_seq_printf(s, fmt, *(type *)data);			\
41	return !trace_seq_has_overflowed(s);				\
42}									\
43const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
44
45DEFINE_BASIC_PRINT_TYPE_FUNC(u8,  u8,  "%u")
46DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
47DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
48DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
49DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  s8,  "%d")
50DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
51DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
52DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
53DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
54DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
55DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
56DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
57DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
58
59int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
60{
61	trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
62	return !trace_seq_has_overflowed(s);
63}
64const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
65
66/* Print type function for string type */
67int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
68{
69	int len = *(u32 *)data >> 16;
70
71	if (!len)
72		trace_seq_puts(s, FAULT_STRING);
73	else
74		trace_seq_printf(s, "\"%s\"",
75				 (const char *)get_loc_data(data, ent));
76	return !trace_seq_has_overflowed(s);
77}
78
79const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
80
81/* Fetch type information table */
82static const struct fetch_type probe_fetch_types[] = {
83	/* Special types */
84	__ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1,
85			    "__data_loc char[]"),
86	__ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
87			    "__data_loc char[]"),
88	__ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1,
89			    "__data_loc char[]"),
90	/* Basic types */
91	ASSIGN_FETCH_TYPE(u8,  u8,  0),
92	ASSIGN_FETCH_TYPE(u16, u16, 0),
93	ASSIGN_FETCH_TYPE(u32, u32, 0),
94	ASSIGN_FETCH_TYPE(u64, u64, 0),
95	ASSIGN_FETCH_TYPE(s8,  u8,  1),
96	ASSIGN_FETCH_TYPE(s16, u16, 1),
97	ASSIGN_FETCH_TYPE(s32, u32, 1),
98	ASSIGN_FETCH_TYPE(s64, u64, 1),
99	ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
100	ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
101	ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
102	ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
103	ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8,  0),
104	ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
105
106	ASSIGN_FETCH_TYPE_END
107};
108
109static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
110{
111	int i;
112
113	/* Reject the symbol/symstr for uprobes */
114	if (type && (flags & TPARG_FL_USER) &&
115	    (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
116		return NULL;
117
118	if (!type)
119		type = DEFAULT_FETCH_TYPE_STR;
120
121	/* Special case: bitfield */
122	if (*type == 'b') {
123		unsigned long bs;
124
125		type = strchr(type, '/');
126		if (!type)
127			goto fail;
128
129		type++;
130		if (kstrtoul(type, 0, &bs))
131			goto fail;
132
133		switch (bs) {
134		case 8:
135			return find_fetch_type("u8", flags);
136		case 16:
137			return find_fetch_type("u16", flags);
138		case 32:
139			return find_fetch_type("u32", flags);
140		case 64:
141			return find_fetch_type("u64", flags);
142		default:
143			goto fail;
144		}
145	}
146
147	for (i = 0; probe_fetch_types[i].name; i++) {
148		if (strcmp(type, probe_fetch_types[i].name) == 0)
149			return &probe_fetch_types[i];
150	}
151
152fail:
153	return NULL;
154}
155
156static struct trace_probe_log trace_probe_log;
157
158void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
159{
160	trace_probe_log.subsystem = subsystem;
161	trace_probe_log.argc = argc;
162	trace_probe_log.argv = argv;
163	trace_probe_log.index = 0;
164}
165
166void trace_probe_log_clear(void)
167{
168	memset(&trace_probe_log, 0, sizeof(trace_probe_log));
169}
170
171void trace_probe_log_set_index(int index)
172{
173	trace_probe_log.index = index;
174}
175
176void __trace_probe_log_err(int offset, int err_type)
177{
178	char *command, *p;
179	int i, len = 0, pos = 0;
180
181	if (!trace_probe_log.argv)
182		return;
183
184	/* Recalculate the length and allocate buffer */
185	for (i = 0; i < trace_probe_log.argc; i++) {
186		if (i == trace_probe_log.index)
187			pos = len;
188		len += strlen(trace_probe_log.argv[i]) + 1;
189	}
190	command = kzalloc(len, GFP_KERNEL);
191	if (!command)
192		return;
193
194	if (trace_probe_log.index >= trace_probe_log.argc) {
195		/**
196		 * Set the error position is next to the last arg + space.
197		 * Note that len includes the terminal null and the cursor
198		 * appears at pos + 1.
199		 */
200		pos = len;
201		offset = 0;
202	}
203
204	/* And make a command string from argv array */
205	p = command;
206	for (i = 0; i < trace_probe_log.argc; i++) {
207		len = strlen(trace_probe_log.argv[i]);
208		strcpy(p, trace_probe_log.argv[i]);
209		p[len] = ' ';
210		p += len + 1;
211	}
212	*(p - 1) = '\0';
213
214	tracing_log_err(NULL, trace_probe_log.subsystem, command,
215			trace_probe_err_text, err_type, pos + offset);
216
217	kfree(command);
218}
219
220/* Split symbol and offset. */
221int traceprobe_split_symbol_offset(char *symbol, long *offset)
222{
223	char *tmp;
224	int ret;
225
226	if (!offset)
227		return -EINVAL;
228
229	tmp = strpbrk(symbol, "+-");
230	if (tmp) {
231		ret = kstrtol(tmp, 0, offset);
232		if (ret)
233			return ret;
234		*tmp = '\0';
235	} else
236		*offset = 0;
237
238	return 0;
239}
240
241/* @buf must has MAX_EVENT_NAME_LEN size */
242int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
243				char *buf, int offset)
244{
245	const char *slash, *event = *pevent;
246	int len;
247
248	slash = strchr(event, '/');
249	if (!slash)
250		slash = strchr(event, '.');
251
252	if (slash) {
253		if (slash == event) {
254			trace_probe_log_err(offset, NO_GROUP_NAME);
255			return -EINVAL;
256		}
257		if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
258			trace_probe_log_err(offset, GROUP_TOO_LONG);
259			return -EINVAL;
260		}
261		strscpy(buf, event, slash - event + 1);
262		if (!is_good_system_name(buf)) {
263			trace_probe_log_err(offset, BAD_GROUP_NAME);
264			return -EINVAL;
265		}
266		*pgroup = buf;
267		*pevent = slash + 1;
268		offset += slash - event + 1;
269		event = *pevent;
270	}
271	len = strlen(event);
272	if (len == 0) {
273		if (slash) {
274			*pevent = NULL;
275			return 0;
276		}
277		trace_probe_log_err(offset, NO_EVENT_NAME);
278		return -EINVAL;
279	} else if (len > MAX_EVENT_NAME_LEN) {
280		trace_probe_log_err(offset, EVENT_TOO_LONG);
281		return -EINVAL;
282	}
283	if (!is_good_name(event)) {
284		trace_probe_log_err(offset, BAD_EVENT_NAME);
285		return -EINVAL;
286	}
287	return 0;
288}
289
290static int parse_trace_event_arg(char *arg, struct fetch_insn *code,
291				 struct traceprobe_parse_context *ctx)
292{
293	struct ftrace_event_field *field;
294	struct list_head *head;
295
296	head = trace_get_fields(ctx->event);
297	list_for_each_entry(field, head, link) {
298		if (!strcmp(arg, field->name)) {
299			code->op = FETCH_OP_TP_ARG;
300			code->data = field;
301			return 0;
302		}
303	}
304	return -ENOENT;
305}
306
307#ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
308
309static u32 btf_type_int(const struct btf_type *t)
310{
311	return *(u32 *)(t + 1);
312}
313
314static bool btf_type_is_char_ptr(struct btf *btf, const struct btf_type *type)
315{
316	const struct btf_type *real_type;
317	u32 intdata;
318	s32 tid;
319
320	real_type = btf_type_skip_modifiers(btf, type->type, &tid);
321	if (!real_type)
322		return false;
323
324	if (BTF_INFO_KIND(real_type->info) != BTF_KIND_INT)
325		return false;
326
327	intdata = btf_type_int(real_type);
328	return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
329		&& BTF_INT_BITS(intdata) == 8;
330}
331
332static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type)
333{
334	const struct btf_type *real_type;
335	const struct btf_array *array;
336	u32 intdata;
337	s32 tid;
338
339	if (BTF_INFO_KIND(type->info) != BTF_KIND_ARRAY)
340		return false;
341
342	array = (const struct btf_array *)(type + 1);
343
344	real_type = btf_type_skip_modifiers(btf, array->type, &tid);
345
346	intdata = btf_type_int(real_type);
347	return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
348		&& BTF_INT_BITS(intdata) == 8;
349}
350
351static int check_prepare_btf_string_fetch(char *typename,
352				struct fetch_insn **pcode,
353				struct traceprobe_parse_context *ctx)
354{
355	struct btf *btf = ctx->btf;
356
357	if (!btf || !ctx->last_type)
358		return 0;
359
360	/* char [] does not need any change. */
361	if (btf_type_is_char_array(btf, ctx->last_type))
362		return 0;
363
364	/* char * requires dereference the pointer. */
365	if (btf_type_is_char_ptr(btf, ctx->last_type)) {
366		struct fetch_insn *code = *pcode + 1;
367
368		if (code->op == FETCH_OP_END) {
369			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
370			return -E2BIG;
371		}
372		if (typename[0] == 'u')
373			code->op = FETCH_OP_UDEREF;
374		else
375			code->op = FETCH_OP_DEREF;
376		code->offset = 0;
377		*pcode = code;
378		return 0;
379	}
380	/* Other types are not available for string */
381	trace_probe_log_err(ctx->offset, BAD_TYPE4STR);
382	return -EINVAL;
383}
384
385static const char *fetch_type_from_btf_type(struct btf *btf,
386					const struct btf_type *type,
387					struct traceprobe_parse_context *ctx)
388{
389	u32 intdata;
390
391	/* TODO: const char * could be converted as a string */
392	switch (BTF_INFO_KIND(type->info)) {
393	case BTF_KIND_ENUM:
394		/* enum is "int", so convert to "s32" */
395		return "s32";
396	case BTF_KIND_ENUM64:
397		return "s64";
398	case BTF_KIND_PTR:
399		/* pointer will be converted to "x??" */
400		if (IS_ENABLED(CONFIG_64BIT))
401			return "x64";
402		else
403			return "x32";
404	case BTF_KIND_INT:
405		intdata = btf_type_int(type);
406		if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) {
407			switch (BTF_INT_BITS(intdata)) {
408			case 8:
409				return "s8";
410			case 16:
411				return "s16";
412			case 32:
413				return "s32";
414			case 64:
415				return "s64";
416			}
417		} else {	/* unsigned */
418			switch (BTF_INT_BITS(intdata)) {
419			case 8:
420				return "u8";
421			case 16:
422				return "u16";
423			case 32:
424				return "u32";
425			case 64:
426				return "u64";
427			}
428			/* bitfield, size is encoded in the type */
429			ctx->last_bitsize = BTF_INT_BITS(intdata);
430			ctx->last_bitoffs += BTF_INT_OFFSET(intdata);
431			return "u64";
432		}
433	}
434	/* TODO: support other types */
435
436	return NULL;
437}
438
439static int query_btf_context(struct traceprobe_parse_context *ctx)
440{
441	const struct btf_param *param;
442	const struct btf_type *type;
443	struct btf *btf;
444	s32 nr;
445
446	if (ctx->btf)
447		return 0;
448
449	if (!ctx->funcname)
450		return -EINVAL;
451
452	type = btf_find_func_proto(ctx->funcname, &btf);
453	if (!type)
454		return -ENOENT;
455
456	ctx->btf = btf;
457	ctx->proto = type;
458
459	/* ctx->params is optional, since func(void) will not have params. */
460	nr = 0;
461	param = btf_get_func_param(type, &nr);
462	if (!IS_ERR_OR_NULL(param)) {
463		/* Hide the first 'data' argument of tracepoint */
464		if (ctx->flags & TPARG_FL_TPOINT) {
465			nr--;
466			param++;
467		}
468	}
469
470	if (nr > 0) {
471		ctx->nr_params = nr;
472		ctx->params = param;
473	} else {
474		ctx->nr_params = 0;
475		ctx->params = NULL;
476	}
477
478	return 0;
479}
480
481static void clear_btf_context(struct traceprobe_parse_context *ctx)
482{
483	if (ctx->btf) {
484		btf_put(ctx->btf);
485		ctx->btf = NULL;
486		ctx->proto = NULL;
487		ctx->params = NULL;
488		ctx->nr_params = 0;
489	}
490}
491
492/* Return 1 if the field separater is arrow operator ('->') */
493static int split_next_field(char *varname, char **next_field,
494			    struct traceprobe_parse_context *ctx)
495{
496	char *field;
497	int ret = 0;
498
499	field = strpbrk(varname, ".-");
500	if (field) {
501		if (field[0] == '-' && field[1] == '>') {
502			field[0] = '\0';
503			field += 2;
504			ret = 1;
505		} else if (field[0] == '.') {
506			field[0] = '\0';
507			field += 1;
508		} else {
509			trace_probe_log_err(ctx->offset + field - varname, BAD_HYPHEN);
510			return -EINVAL;
511		}
512		*next_field = field;
513	}
514
515	return ret;
516}
517
518/*
519 * Parse the field of data structure. The @type must be a pointer type
520 * pointing the target data structure type.
521 */
522static int parse_btf_field(char *fieldname, const struct btf_type *type,
523			   struct fetch_insn **pcode, struct fetch_insn *end,
524			   struct traceprobe_parse_context *ctx)
525{
526	struct fetch_insn *code = *pcode;
527	const struct btf_member *field;
528	u32 bitoffs, anon_offs;
529	char *next;
530	int is_ptr;
531	s32 tid;
532
533	do {
534		/* Outer loop for solving arrow operator ('->') */
535		if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) {
536			trace_probe_log_err(ctx->offset, NO_PTR_STRCT);
537			return -EINVAL;
538		}
539		/* Convert a struct pointer type to a struct type */
540		type = btf_type_skip_modifiers(ctx->btf, type->type, &tid);
541		if (!type) {
542			trace_probe_log_err(ctx->offset, BAD_BTF_TID);
543			return -EINVAL;
544		}
545
546		bitoffs = 0;
547		do {
548			/* Inner loop for solving dot operator ('.') */
549			next = NULL;
550			is_ptr = split_next_field(fieldname, &next, ctx);
551			if (is_ptr < 0)
552				return is_ptr;
553
554			anon_offs = 0;
555			field = btf_find_struct_member(ctx->btf, type, fieldname,
556						       &anon_offs);
557			if (IS_ERR(field)) {
558				trace_probe_log_err(ctx->offset, BAD_BTF_TID);
559				return PTR_ERR(field);
560			}
561			if (!field) {
562				trace_probe_log_err(ctx->offset, NO_BTF_FIELD);
563				return -ENOENT;
564			}
565			/* Add anonymous structure/union offset */
566			bitoffs += anon_offs;
567
568			/* Accumulate the bit-offsets of the dot-connected fields */
569			if (btf_type_kflag(type)) {
570				bitoffs += BTF_MEMBER_BIT_OFFSET(field->offset);
571				ctx->last_bitsize = BTF_MEMBER_BITFIELD_SIZE(field->offset);
572			} else {
573				bitoffs += field->offset;
574				ctx->last_bitsize = 0;
575			}
576
577			type = btf_type_skip_modifiers(ctx->btf, field->type, &tid);
578			if (!type) {
579				trace_probe_log_err(ctx->offset, BAD_BTF_TID);
580				return -EINVAL;
581			}
582
583			ctx->offset += next - fieldname;
584			fieldname = next;
585		} while (!is_ptr && fieldname);
586
587		if (++code == end) {
588			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
589			return -EINVAL;
590		}
591		code->op = FETCH_OP_DEREF;	/* TODO: user deref support */
592		code->offset = bitoffs / 8;
593		*pcode = code;
594
595		ctx->last_bitoffs = bitoffs % 8;
596		ctx->last_type = type;
597	} while (fieldname);
598
599	return 0;
600}
601
602static int __store_entry_arg(struct trace_probe *tp, int argnum);
603
604static int parse_btf_arg(char *varname,
605			 struct fetch_insn **pcode, struct fetch_insn *end,
606			 struct traceprobe_parse_context *ctx)
607{
608	struct fetch_insn *code = *pcode;
609	const struct btf_param *params;
610	const struct btf_type *type;
611	char *field = NULL;
612	int i, is_ptr, ret;
613	u32 tid;
614
615	if (WARN_ON_ONCE(!ctx->funcname))
616		return -EINVAL;
617
618	is_ptr = split_next_field(varname, &field, ctx);
619	if (is_ptr < 0)
620		return is_ptr;
621	if (!is_ptr && field) {
622		/* dot-connected field on an argument is not supported. */
623		trace_probe_log_err(ctx->offset + field - varname,
624				    NOSUP_DAT_ARG);
625		return -EOPNOTSUPP;
626	}
627
628	if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) {
629		code->op = FETCH_OP_RETVAL;
630		/* Check whether the function return type is not void */
631		if (query_btf_context(ctx) == 0) {
632			if (ctx->proto->type == 0) {
633				trace_probe_log_err(ctx->offset, NO_RETVAL);
634				return -ENOENT;
635			}
636			tid = ctx->proto->type;
637			goto found;
638		}
639		if (field) {
640			trace_probe_log_err(ctx->offset + field - varname,
641					    NO_BTF_ENTRY);
642			return -ENOENT;
643		}
644		return 0;
645	}
646
647	if (!ctx->btf) {
648		ret = query_btf_context(ctx);
649		if (ret < 0 || ctx->nr_params == 0) {
650			trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
651			return PTR_ERR(params);
652		}
653	}
654	params = ctx->params;
655
656	for (i = 0; i < ctx->nr_params; i++) {
657		const char *name = btf_name_by_offset(ctx->btf, params[i].name_off);
658
659		if (name && !strcmp(name, varname)) {
660			if (tparg_is_function_entry(ctx->flags)) {
661				code->op = FETCH_OP_ARG;
662				if (ctx->flags & TPARG_FL_TPOINT)
663					code->param = i + 1;
664				else
665					code->param = i;
666			} else if (tparg_is_function_return(ctx->flags)) {
667				code->op = FETCH_OP_EDATA;
668				ret = __store_entry_arg(ctx->tp, i);
669				if (ret < 0) {
670					/* internal error */
671					return ret;
672				}
673				code->offset = ret;
674			}
675			tid = params[i].type;
676			goto found;
677		}
678	}
679	trace_probe_log_err(ctx->offset, NO_BTFARG);
680	return -ENOENT;
681
682found:
683	type = btf_type_skip_modifiers(ctx->btf, tid, &tid);
684	if (!type) {
685		trace_probe_log_err(ctx->offset, BAD_BTF_TID);
686		return -EINVAL;
687	}
688	/* Initialize the last type information */
689	ctx->last_type = type;
690	ctx->last_bitoffs = 0;
691	ctx->last_bitsize = 0;
692	if (field) {
693		ctx->offset += field - varname;
694		return parse_btf_field(field, type, pcode, end, ctx);
695	}
696	return 0;
697}
698
699static const struct fetch_type *find_fetch_type_from_btf_type(
700					struct traceprobe_parse_context *ctx)
701{
702	struct btf *btf = ctx->btf;
703	const char *typestr = NULL;
704
705	if (btf && ctx->last_type)
706		typestr = fetch_type_from_btf_type(btf, ctx->last_type, ctx);
707
708	return find_fetch_type(typestr, ctx->flags);
709}
710
711static int parse_btf_bitfield(struct fetch_insn **pcode,
712			      struct traceprobe_parse_context *ctx)
713{
714	struct fetch_insn *code = *pcode;
715
716	if ((ctx->last_bitsize % 8 == 0) && ctx->last_bitoffs == 0)
717		return 0;
718
719	code++;
720	if (code->op != FETCH_OP_NOP) {
721		trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
722		return -EINVAL;
723	}
724	*pcode = code;
725
726	code->op = FETCH_OP_MOD_BF;
727	code->lshift = 64 - (ctx->last_bitsize + ctx->last_bitoffs);
728	code->rshift = 64 - ctx->last_bitsize;
729	code->basesize = 64 / 8;
730	return 0;
731}
732
733#else
734static void clear_btf_context(struct traceprobe_parse_context *ctx)
735{
736	ctx->btf = NULL;
737}
738
739static int query_btf_context(struct traceprobe_parse_context *ctx)
740{
741	return -EOPNOTSUPP;
742}
743
744static int parse_btf_arg(char *varname,
745			 struct fetch_insn **pcode, struct fetch_insn *end,
746			 struct traceprobe_parse_context *ctx)
747{
748	trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
749	return -EOPNOTSUPP;
750}
751
752static int parse_btf_bitfield(struct fetch_insn **pcode,
753			      struct traceprobe_parse_context *ctx)
754{
755	trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
756	return -EOPNOTSUPP;
757}
758
759#define find_fetch_type_from_btf_type(ctx)		\
760	find_fetch_type(NULL, ctx->flags)
761
762static int check_prepare_btf_string_fetch(char *typename,
763				struct fetch_insn **pcode,
764				struct traceprobe_parse_context *ctx)
765{
766	return 0;
767}
768
769#endif
770
771#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
772
773static int __store_entry_arg(struct trace_probe *tp, int argnum)
774{
775	struct probe_entry_arg *earg = tp->entry_arg;
776	bool match = false;
777	int i, offset;
778
779	if (!earg) {
780		earg = kzalloc(sizeof(*tp->entry_arg), GFP_KERNEL);
781		if (!earg)
782			return -ENOMEM;
783		earg->size = 2 * tp->nr_args + 1;
784		earg->code = kcalloc(earg->size, sizeof(struct fetch_insn),
785				     GFP_KERNEL);
786		if (!earg->code) {
787			kfree(earg);
788			return -ENOMEM;
789		}
790		/* Fill the code buffer with 'end' to simplify it */
791		for (i = 0; i < earg->size; i++)
792			earg->code[i].op = FETCH_OP_END;
793		tp->entry_arg = earg;
794	}
795
796	offset = 0;
797	for (i = 0; i < earg->size - 1; i++) {
798		switch (earg->code[i].op) {
799		case FETCH_OP_END:
800			earg->code[i].op = FETCH_OP_ARG;
801			earg->code[i].param = argnum;
802			earg->code[i + 1].op = FETCH_OP_ST_EDATA;
803			earg->code[i + 1].offset = offset;
804			return offset;
805		case FETCH_OP_ARG:
806			match = (earg->code[i].param == argnum);
807			break;
808		case FETCH_OP_ST_EDATA:
809			offset = earg->code[i].offset;
810			if (match)
811				return offset;
812			offset += sizeof(unsigned long);
813			break;
814		default:
815			break;
816		}
817	}
818	return -ENOSPC;
819}
820
821int traceprobe_get_entry_data_size(struct trace_probe *tp)
822{
823	struct probe_entry_arg *earg = tp->entry_arg;
824	int i, size = 0;
825
826	if (!earg)
827		return 0;
828
829	for (i = 0; i < earg->size; i++) {
830		switch (earg->code[i].op) {
831		case FETCH_OP_END:
832			goto out;
833		case FETCH_OP_ST_EDATA:
834			size = earg->code[i].offset + sizeof(unsigned long);
835			break;
836		default:
837			break;
838		}
839	}
840out:
841	return size;
842}
843
844void store_trace_entry_data(void *edata, struct trace_probe *tp, struct pt_regs *regs)
845{
846	struct probe_entry_arg *earg = tp->entry_arg;
847	unsigned long val = 0;
848	int i;
849
850	if (!earg)
851		return;
852
853	for (i = 0; i < earg->size; i++) {
854		struct fetch_insn *code = &earg->code[i];
855
856		switch (code->op) {
857		case FETCH_OP_ARG:
858			val = regs_get_kernel_argument(regs, code->param);
859			break;
860		case FETCH_OP_ST_EDATA:
861			*(unsigned long *)((unsigned long)edata + code->offset) = val;
862			break;
863		case FETCH_OP_END:
864			goto end;
865		default:
866			break;
867		}
868	}
869end:
870	return;
871}
872NOKPROBE_SYMBOL(store_trace_entry_data)
873#endif
874
875#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
876
877/* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */
878static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
879			    struct fetch_insn **pcode,
880			    struct fetch_insn *end,
881			    struct traceprobe_parse_context *ctx)
882{
883	struct fetch_insn *code = *pcode;
884	int err = TP_ERR_BAD_VAR;
885	char *arg = orig_arg + 1;
886	unsigned long param;
887	int ret = 0;
888	int len;
889
890	if (ctx->flags & TPARG_FL_TEVENT) {
891		if (code->data)
892			return -EFAULT;
893		ret = parse_trace_event_arg(arg, code, ctx);
894		if (!ret)
895			return 0;
896		if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
897			code->op = FETCH_OP_COMM;
898			return 0;
899		}
900		/* backward compatibility */
901		ctx->offset = 0;
902		goto inval;
903	}
904
905	if (str_has_prefix(arg, "retval")) {
906		if (!(ctx->flags & TPARG_FL_RETURN)) {
907			err = TP_ERR_RETVAL_ON_PROBE;
908			goto inval;
909		}
910		if (!(ctx->flags & TPARG_FL_KERNEL) ||
911		    !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
912			code->op = FETCH_OP_RETVAL;
913			return 0;
914		}
915		return parse_btf_arg(orig_arg, pcode, end, ctx);
916	}
917
918	len = str_has_prefix(arg, "stack");
919	if (len) {
920
921		if (arg[len] == '\0') {
922			code->op = FETCH_OP_STACKP;
923			return 0;
924		}
925
926		if (isdigit(arg[len])) {
927			ret = kstrtoul(arg + len, 10, &param);
928			if (ret)
929				goto inval;
930
931			if ((ctx->flags & TPARG_FL_KERNEL) &&
932			    param > PARAM_MAX_STACK) {
933				err = TP_ERR_BAD_STACK_NUM;
934				goto inval;
935			}
936			code->op = FETCH_OP_STACK;
937			code->param = (unsigned int)param;
938			return 0;
939		}
940		goto inval;
941	}
942
943	if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
944		code->op = FETCH_OP_COMM;
945		return 0;
946	}
947
948#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
949	len = str_has_prefix(arg, "arg");
950	if (len) {
951		ret = kstrtoul(arg + len, 10, &param);
952		if (ret)
953			goto inval;
954
955		if (!param || param > PARAM_MAX_STACK) {
956			err = TP_ERR_BAD_ARG_NUM;
957			goto inval;
958		}
959		param--; /* argN starts from 1, but internal arg[N] starts from 0 */
960
961		if (tparg_is_function_entry(ctx->flags)) {
962			code->op = FETCH_OP_ARG;
963			code->param = (unsigned int)param;
964			/*
965			 * The tracepoint probe will probe a stub function, and the
966			 * first parameter of the stub is a dummy and should be ignored.
967			 */
968			if (ctx->flags & TPARG_FL_TPOINT)
969				code->param++;
970		} else if (tparg_is_function_return(ctx->flags)) {
971			/* function entry argument access from return probe */
972			ret = __store_entry_arg(ctx->tp, param);
973			if (ret < 0)	/* This error should be an internal error */
974				return ret;
975
976			code->op = FETCH_OP_EDATA;
977			code->offset = ret;
978		} else {
979			err = TP_ERR_NOFENTRY_ARGS;
980			goto inval;
981		}
982		return 0;
983	}
984#endif
985
986inval:
987	__trace_probe_log_err(ctx->offset, err);
988	return -EINVAL;
989}
990
991static int str_to_immediate(char *str, unsigned long *imm)
992{
993	if (isdigit(str[0]))
994		return kstrtoul(str, 0, imm);
995	else if (str[0] == '-')
996		return kstrtol(str, 0, (long *)imm);
997	else if (str[0] == '+')
998		return kstrtol(str + 1, 0, (long *)imm);
999	return -EINVAL;
1000}
1001
1002static int __parse_imm_string(char *str, char **pbuf, int offs)
1003{
1004	size_t len = strlen(str);
1005
1006	if (str[len - 1] != '"') {
1007		trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
1008		return -EINVAL;
1009	}
1010	*pbuf = kstrndup(str, len - 1, GFP_KERNEL);
1011	if (!*pbuf)
1012		return -ENOMEM;
1013	return 0;
1014}
1015
1016/* Recursive argument parser */
1017static int
1018parse_probe_arg(char *arg, const struct fetch_type *type,
1019		struct fetch_insn **pcode, struct fetch_insn *end,
1020		struct traceprobe_parse_context *ctx)
1021{
1022	struct fetch_insn *code = *pcode;
1023	unsigned long param;
1024	int deref = FETCH_OP_DEREF;
1025	long offset = 0;
1026	char *tmp;
1027	int ret = 0;
1028
1029	switch (arg[0]) {
1030	case '$':
1031		ret = parse_probe_vars(arg, type, pcode, end, ctx);
1032		break;
1033
1034	case '%':	/* named register */
1035		if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
1036			/* eprobe and fprobe do not handle registers */
1037			trace_probe_log_err(ctx->offset, BAD_VAR);
1038			break;
1039		}
1040		ret = regs_query_register_offset(arg + 1);
1041		if (ret >= 0) {
1042			code->op = FETCH_OP_REG;
1043			code->param = (unsigned int)ret;
1044			ret = 0;
1045		} else
1046			trace_probe_log_err(ctx->offset, BAD_REG_NAME);
1047		break;
1048
1049	case '@':	/* memory, file-offset or symbol */
1050		if (isdigit(arg[1])) {
1051			ret = kstrtoul(arg + 1, 0, &param);
1052			if (ret) {
1053				trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
1054				break;
1055			}
1056			/* load address */
1057			code->op = FETCH_OP_IMM;
1058			code->immediate = param;
1059		} else if (arg[1] == '+') {
1060			/* kprobes don't support file offsets */
1061			if (ctx->flags & TPARG_FL_KERNEL) {
1062				trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
1063				return -EINVAL;
1064			}
1065			ret = kstrtol(arg + 2, 0, &offset);
1066			if (ret) {
1067				trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
1068				break;
1069			}
1070
1071			code->op = FETCH_OP_FOFFS;
1072			code->immediate = (unsigned long)offset;  // imm64?
1073		} else {
1074			/* uprobes don't support symbols */
1075			if (!(ctx->flags & TPARG_FL_KERNEL)) {
1076				trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
1077				return -EINVAL;
1078			}
1079			/* Preserve symbol for updating */
1080			code->op = FETCH_NOP_SYMBOL;
1081			code->data = kstrdup(arg + 1, GFP_KERNEL);
1082			if (!code->data)
1083				return -ENOMEM;
1084			if (++code == end) {
1085				trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1086				return -EINVAL;
1087			}
1088			code->op = FETCH_OP_IMM;
1089			code->immediate = 0;
1090		}
1091		/* These are fetching from memory */
1092		if (++code == end) {
1093			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1094			return -EINVAL;
1095		}
1096		*pcode = code;
1097		code->op = FETCH_OP_DEREF;
1098		code->offset = offset;
1099		break;
1100
1101	case '+':	/* deref memory */
1102	case '-':
1103		if (arg[1] == 'u') {
1104			deref = FETCH_OP_UDEREF;
1105			arg[1] = arg[0];
1106			arg++;
1107		}
1108		if (arg[0] == '+')
1109			arg++;	/* Skip '+', because kstrtol() rejects it. */
1110		tmp = strchr(arg, '(');
1111		if (!tmp) {
1112			trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
1113			return -EINVAL;
1114		}
1115		*tmp = '\0';
1116		ret = kstrtol(arg, 0, &offset);
1117		if (ret) {
1118			trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
1119			break;
1120		}
1121		ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
1122		arg = tmp + 1;
1123		tmp = strrchr(arg, ')');
1124		if (!tmp) {
1125			trace_probe_log_err(ctx->offset + strlen(arg),
1126					    DEREF_OPEN_BRACE);
1127			return -EINVAL;
1128		} else {
1129			const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags);
1130			int cur_offs = ctx->offset;
1131
1132			*tmp = '\0';
1133			ret = parse_probe_arg(arg, t2, &code, end, ctx);
1134			if (ret)
1135				break;
1136			ctx->offset = cur_offs;
1137			if (code->op == FETCH_OP_COMM ||
1138			    code->op == FETCH_OP_DATA) {
1139				trace_probe_log_err(ctx->offset, COMM_CANT_DEREF);
1140				return -EINVAL;
1141			}
1142			if (++code == end) {
1143				trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1144				return -EINVAL;
1145			}
1146			*pcode = code;
1147
1148			code->op = deref;
1149			code->offset = offset;
1150			/* Reset the last type if used */
1151			ctx->last_type = NULL;
1152		}
1153		break;
1154	case '\\':	/* Immediate value */
1155		if (arg[1] == '"') {	/* Immediate string */
1156			ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
1157			if (ret)
1158				break;
1159			code->op = FETCH_OP_DATA;
1160			code->data = tmp;
1161		} else {
1162			ret = str_to_immediate(arg + 1, &code->immediate);
1163			if (ret)
1164				trace_probe_log_err(ctx->offset + 1, BAD_IMM);
1165			else
1166				code->op = FETCH_OP_IMM;
1167		}
1168		break;
1169	default:
1170		if (isalpha(arg[0]) || arg[0] == '_') {	/* BTF variable */
1171			if (!tparg_is_function_entry(ctx->flags) &&
1172			    !tparg_is_function_return(ctx->flags)) {
1173				trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
1174				return -EINVAL;
1175			}
1176			ret = parse_btf_arg(arg, pcode, end, ctx);
1177			break;
1178		}
1179	}
1180	if (!ret && code->op == FETCH_OP_NOP) {
1181		/* Parsed, but do not find fetch method */
1182		trace_probe_log_err(ctx->offset, BAD_FETCH_ARG);
1183		ret = -EINVAL;
1184	}
1185	return ret;
1186}
1187
1188/* Bitfield type needs to be parsed into a fetch function */
1189static int __parse_bitfield_probe_arg(const char *bf,
1190				      const struct fetch_type *t,
1191				      struct fetch_insn **pcode)
1192{
1193	struct fetch_insn *code = *pcode;
1194	unsigned long bw, bo;
1195	char *tail;
1196
1197	if (*bf != 'b')
1198		return 0;
1199
1200	bw = simple_strtoul(bf + 1, &tail, 0);	/* Use simple one */
1201
1202	if (bw == 0 || *tail != '@')
1203		return -EINVAL;
1204
1205	bf = tail + 1;
1206	bo = simple_strtoul(bf, &tail, 0);
1207
1208	if (tail == bf || *tail != '/')
1209		return -EINVAL;
1210	code++;
1211	if (code->op != FETCH_OP_NOP)
1212		return -EINVAL;
1213	*pcode = code;
1214
1215	code->op = FETCH_OP_MOD_BF;
1216	code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
1217	code->rshift = BYTES_TO_BITS(t->size) - bw;
1218	code->basesize = t->size;
1219
1220	return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
1221}
1222
1223/* Split type part from @arg and return it. */
1224static char *parse_probe_arg_type(char *arg, struct probe_arg *parg,
1225				  struct traceprobe_parse_context *ctx)
1226{
1227	char *t = NULL, *t2, *t3;
1228	int offs;
1229
1230	t = strchr(arg, ':');
1231	if (t) {
1232		*t++ = '\0';
1233		t2 = strchr(t, '[');
1234		if (t2) {
1235			*t2++ = '\0';
1236			t3 = strchr(t2, ']');
1237			if (!t3) {
1238				offs = t2 + strlen(t2) - arg;
1239
1240				trace_probe_log_err(ctx->offset + offs,
1241						    ARRAY_NO_CLOSE);
1242				return ERR_PTR(-EINVAL);
1243			} else if (t3[1] != '\0') {
1244				trace_probe_log_err(ctx->offset + t3 + 1 - arg,
1245						    BAD_ARRAY_SUFFIX);
1246				return ERR_PTR(-EINVAL);
1247			}
1248			*t3 = '\0';
1249			if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
1250				trace_probe_log_err(ctx->offset + t2 - arg,
1251						    BAD_ARRAY_NUM);
1252				return ERR_PTR(-EINVAL);
1253			}
1254			if (parg->count > MAX_ARRAY_LEN) {
1255				trace_probe_log_err(ctx->offset + t2 - arg,
1256						    ARRAY_TOO_BIG);
1257				return ERR_PTR(-EINVAL);
1258			}
1259		}
1260	}
1261	offs = t ? t - arg : 0;
1262
1263	/*
1264	 * Since $comm and immediate string can not be dereferenced,
1265	 * we can find those by strcmp. But ignore for eprobes.
1266	 */
1267	if (!(ctx->flags & TPARG_FL_TEVENT) &&
1268	    (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
1269	     strncmp(arg, "\\\"", 2) == 0)) {
1270		/* The type of $comm must be "string", and not an array type. */
1271		if (parg->count || (t && strcmp(t, "string"))) {
1272			trace_probe_log_err(ctx->offset + offs, NEED_STRING_TYPE);
1273			return ERR_PTR(-EINVAL);
1274		}
1275		parg->type = find_fetch_type("string", ctx->flags);
1276	} else
1277		parg->type = find_fetch_type(t, ctx->flags);
1278
1279	if (!parg->type) {
1280		trace_probe_log_err(ctx->offset + offs, BAD_TYPE);
1281		return ERR_PTR(-EINVAL);
1282	}
1283
1284	return t;
1285}
1286
1287/* After parsing, adjust the fetch_insn according to the probe_arg */
1288static int finalize_fetch_insn(struct fetch_insn *code,
1289			       struct probe_arg *parg,
1290			       char *type,
1291			       int type_offset,
1292			       struct traceprobe_parse_context *ctx)
1293{
1294	struct fetch_insn *scode;
1295	int ret;
1296
1297	/* Store operation */
1298	if (parg->type->is_string) {
1299		/* Check bad combination of the type and the last fetch_insn. */
1300		if (!strcmp(parg->type->name, "symstr")) {
1301			if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
1302			    code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
1303			    code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
1304				trace_probe_log_err(ctx->offset + type_offset,
1305						    BAD_SYMSTRING);
1306				return -EINVAL;
1307			}
1308		} else {
1309			if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
1310			    code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
1311			    code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
1312				trace_probe_log_err(ctx->offset + type_offset,
1313						    BAD_STRING);
1314				return -EINVAL;
1315			}
1316		}
1317
1318		if (!strcmp(parg->type->name, "symstr") ||
1319		    (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
1320		     code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
1321		     parg->count) {
1322			/*
1323			 * IMM, DATA and COMM is pointing actual address, those
1324			 * must be kept, and if parg->count != 0, this is an
1325			 * array of string pointers instead of string address
1326			 * itself.
1327			 * For the symstr, it doesn't need to dereference, thus
1328			 * it just get the value.
1329			 */
1330			code++;
1331			if (code->op != FETCH_OP_NOP) {
1332				trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1333				return -EINVAL;
1334			}
1335		}
1336
1337		/* If op == DEREF, replace it with STRING */
1338		if (!strcmp(parg->type->name, "ustring") ||
1339		    code->op == FETCH_OP_UDEREF)
1340			code->op = FETCH_OP_ST_USTRING;
1341		else if (!strcmp(parg->type->name, "symstr"))
1342			code->op = FETCH_OP_ST_SYMSTR;
1343		else
1344			code->op = FETCH_OP_ST_STRING;
1345		code->size = parg->type->size;
1346		parg->dynamic = true;
1347	} else if (code->op == FETCH_OP_DEREF) {
1348		code->op = FETCH_OP_ST_MEM;
1349		code->size = parg->type->size;
1350	} else if (code->op == FETCH_OP_UDEREF) {
1351		code->op = FETCH_OP_ST_UMEM;
1352		code->size = parg->type->size;
1353	} else {
1354		code++;
1355		if (code->op != FETCH_OP_NOP) {
1356			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1357			return -E2BIG;
1358		}
1359		code->op = FETCH_OP_ST_RAW;
1360		code->size = parg->type->size;
1361	}
1362
1363	/* Save storing fetch_insn. */
1364	scode = code;
1365
1366	/* Modify operation */
1367	if (type != NULL) {
1368		/* Bitfield needs a special fetch_insn. */
1369		ret = __parse_bitfield_probe_arg(type, parg->type, &code);
1370		if (ret) {
1371			trace_probe_log_err(ctx->offset + type_offset, BAD_BITFIELD);
1372			return ret;
1373		}
1374	} else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1375		   ctx->last_type) {
1376		/* If user not specified the type, try parsing BTF bitfield. */
1377		ret = parse_btf_bitfield(&code, ctx);
1378		if (ret)
1379			return ret;
1380	}
1381
1382	/* Loop(Array) operation */
1383	if (parg->count) {
1384		if (scode->op != FETCH_OP_ST_MEM &&
1385		    scode->op != FETCH_OP_ST_STRING &&
1386		    scode->op != FETCH_OP_ST_USTRING) {
1387			trace_probe_log_err(ctx->offset + type_offset, BAD_STRING);
1388			return -EINVAL;
1389		}
1390		code++;
1391		if (code->op != FETCH_OP_NOP) {
1392			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
1393			return -E2BIG;
1394		}
1395		code->op = FETCH_OP_LP_ARRAY;
1396		code->param = parg->count;
1397	}
1398
1399	/* Finalize the fetch_insn array. */
1400	code++;
1401	code->op = FETCH_OP_END;
1402
1403	return 0;
1404}
1405
1406/* String length checking wrapper */
1407static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
1408					   struct probe_arg *parg,
1409					   struct traceprobe_parse_context *ctx)
1410{
1411	struct fetch_insn *code, *tmp = NULL;
1412	char *type, *arg;
1413	int ret, len;
1414
1415	len = strlen(argv);
1416	if (len > MAX_ARGSTR_LEN) {
1417		trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
1418		return -E2BIG;
1419	} else if (len == 0) {
1420		trace_probe_log_err(ctx->offset, NO_ARG_BODY);
1421		return -EINVAL;
1422	}
1423
1424	arg = kstrdup(argv, GFP_KERNEL);
1425	if (!arg)
1426		return -ENOMEM;
1427
1428	parg->comm = kstrdup(arg, GFP_KERNEL);
1429	if (!parg->comm) {
1430		ret = -ENOMEM;
1431		goto out;
1432	}
1433
1434	type = parse_probe_arg_type(arg, parg, ctx);
1435	if (IS_ERR(type)) {
1436		ret = PTR_ERR(type);
1437		goto out;
1438	}
1439
1440	code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
1441	if (!code) {
1442		ret = -ENOMEM;
1443		goto out;
1444	}
1445	code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
1446
1447	ctx->last_type = NULL;
1448	ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
1449			      ctx);
1450	if (ret < 0)
1451		goto fail;
1452
1453	/* Update storing type if BTF is available */
1454	if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
1455	    ctx->last_type) {
1456		if (!type) {
1457			parg->type = find_fetch_type_from_btf_type(ctx);
1458		} else if (strstr(type, "string")) {
1459			ret = check_prepare_btf_string_fetch(type, &code, ctx);
1460			if (ret)
1461				goto fail;
1462		}
1463	}
1464	parg->offset = *size;
1465	*size += parg->type->size * (parg->count ?: 1);
1466
1467	if (parg->count) {
1468		len = strlen(parg->type->fmttype) + 6;
1469		parg->fmt = kmalloc(len, GFP_KERNEL);
1470		if (!parg->fmt) {
1471			ret = -ENOMEM;
1472			goto fail;
1473		}
1474		snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
1475			 parg->count);
1476	}
1477
1478	ret = finalize_fetch_insn(code, parg, type, type ? type - arg : 0, ctx);
1479	if (ret < 0)
1480		goto fail;
1481
1482	for (; code < tmp + FETCH_INSN_MAX; code++)
1483		if (code->op == FETCH_OP_END)
1484			break;
1485	/* Shrink down the code buffer */
1486	parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
1487	if (!parg->code)
1488		ret = -ENOMEM;
1489	else
1490		memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
1491
1492fail:
1493	if (ret < 0) {
1494		for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
1495			if (code->op == FETCH_NOP_SYMBOL ||
1496			    code->op == FETCH_OP_DATA)
1497				kfree(code->data);
1498	}
1499	kfree(tmp);
1500out:
1501	kfree(arg);
1502
1503	return ret;
1504}
1505
1506/* Return 1 if name is reserved or already used by another argument */
1507static int traceprobe_conflict_field_name(const char *name,
1508					  struct probe_arg *args, int narg)
1509{
1510	int i;
1511
1512	for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
1513		if (strcmp(reserved_field_names[i], name) == 0)
1514			return 1;
1515
1516	for (i = 0; i < narg; i++)
1517		if (strcmp(args[i].name, name) == 0)
1518			return 1;
1519
1520	return 0;
1521}
1522
1523static char *generate_probe_arg_name(const char *arg, int idx)
1524{
1525	char *name = NULL;
1526	const char *end;
1527
1528	/*
1529	 * If argument name is omitted, try arg as a name (BTF variable)
1530	 * or "argN".
1531	 */
1532	if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
1533		end = strchr(arg, ':');
1534		if (!end)
1535			end = arg + strlen(arg);
1536
1537		name = kmemdup_nul(arg, end - arg, GFP_KERNEL);
1538		if (!name || !is_good_name(name)) {
1539			kfree(name);
1540			name = NULL;
1541		}
1542	}
1543
1544	if (!name)
1545		name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
1546
1547	return name;
1548}
1549
1550int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
1551			       struct traceprobe_parse_context *ctx)
1552{
1553	struct probe_arg *parg = &tp->args[i];
1554	const char *body;
1555
1556	ctx->tp = tp;
1557	body = strchr(arg, '=');
1558	if (body) {
1559		if (body - arg > MAX_ARG_NAME_LEN) {
1560			trace_probe_log_err(0, ARG_NAME_TOO_LONG);
1561			return -EINVAL;
1562		} else if (body == arg) {
1563			trace_probe_log_err(0, NO_ARG_NAME);
1564			return -EINVAL;
1565		}
1566		parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
1567		body++;
1568	} else {
1569		parg->name = generate_probe_arg_name(arg, i);
1570		body = arg;
1571	}
1572	if (!parg->name)
1573		return -ENOMEM;
1574
1575	if (!is_good_name(parg->name)) {
1576		trace_probe_log_err(0, BAD_ARG_NAME);
1577		return -EINVAL;
1578	}
1579	if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
1580		trace_probe_log_err(0, USED_ARG_NAME);
1581		return -EINVAL;
1582	}
1583	ctx->offset = body - arg;
1584	/* Parse fetch argument */
1585	return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);
1586}
1587
1588void traceprobe_free_probe_arg(struct probe_arg *arg)
1589{
1590	struct fetch_insn *code = arg->code;
1591
1592	while (code && code->op != FETCH_OP_END) {
1593		if (code->op == FETCH_NOP_SYMBOL ||
1594		    code->op == FETCH_OP_DATA)
1595			kfree(code->data);
1596		code++;
1597	}
1598	kfree(arg->code);
1599	kfree(arg->name);
1600	kfree(arg->comm);
1601	kfree(arg->fmt);
1602}
1603
1604static int argv_has_var_arg(int argc, const char *argv[], int *args_idx,
1605			    struct traceprobe_parse_context *ctx)
1606{
1607	int i, found = 0;
1608
1609	for (i = 0; i < argc; i++)
1610		if (str_has_prefix(argv[i], "$arg")) {
1611			trace_probe_log_set_index(i + 2);
1612
1613			if (!tparg_is_function_entry(ctx->flags) &&
1614			    !tparg_is_function_return(ctx->flags)) {
1615				trace_probe_log_err(0, NOFENTRY_ARGS);
1616				return -EINVAL;
1617			}
1618
1619			if (isdigit(argv[i][4])) {
1620				found = 1;
1621				continue;
1622			}
1623
1624			if (argv[i][4] != '*') {
1625				trace_probe_log_err(0, BAD_VAR);
1626				return -EINVAL;
1627			}
1628
1629			if (*args_idx >= 0 && *args_idx < argc) {
1630				trace_probe_log_err(0, DOUBLE_ARGS);
1631				return -EINVAL;
1632			}
1633			found = 1;
1634			*args_idx = i;
1635		}
1636
1637	return found;
1638}
1639
1640static int sprint_nth_btf_arg(int idx, const char *type,
1641			      char *buf, int bufsize,
1642			      struct traceprobe_parse_context *ctx)
1643{
1644	const char *name;
1645	int ret;
1646
1647	if (idx >= ctx->nr_params) {
1648		trace_probe_log_err(0, NO_BTFARG);
1649		return -ENOENT;
1650	}
1651	name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off);
1652	if (!name) {
1653		trace_probe_log_err(0, NO_BTF_ENTRY);
1654		return -ENOENT;
1655	}
1656	ret = snprintf(buf, bufsize, "%s%s", name, type);
1657	if (ret >= bufsize) {
1658		trace_probe_log_err(0, ARGS_2LONG);
1659		return -E2BIG;
1660	}
1661	return ret;
1662}
1663
1664/* Return new_argv which must be freed after use */
1665const char **traceprobe_expand_meta_args(int argc, const char *argv[],
1666					 int *new_argc, char *buf, int bufsize,
1667					 struct traceprobe_parse_context *ctx)
1668{
1669	const struct btf_param *params = NULL;
1670	int i, j, n, used, ret, args_idx = -1;
1671	const char **new_argv = NULL;
1672
1673	ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
1674	if (ret < 0)
1675		return ERR_PTR(ret);
1676
1677	if (!ret) {
1678		*new_argc = argc;
1679		return NULL;
1680	}
1681
1682	ret = query_btf_context(ctx);
1683	if (ret < 0 || ctx->nr_params == 0) {
1684		if (args_idx != -1) {
1685			/* $arg* requires BTF info */
1686			trace_probe_log_err(0, NOSUP_BTFARG);
1687			return (const char **)params;
1688		}
1689		*new_argc = argc;
1690		return NULL;
1691	}
1692
1693	if (args_idx >= 0)
1694		*new_argc = argc + ctx->nr_params - 1;
1695	else
1696		*new_argc = argc;
1697
1698	new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL);
1699	if (!new_argv)
1700		return ERR_PTR(-ENOMEM);
1701
1702	used = 0;
1703	for (i = 0, j = 0; i < argc; i++) {
1704		trace_probe_log_set_index(i + 2);
1705		if (i == args_idx) {
1706			for (n = 0; n < ctx->nr_params; n++) {
1707				ret = sprint_nth_btf_arg(n, "", buf + used,
1708							 bufsize - used, ctx);
1709				if (ret < 0)
1710					goto error;
1711
1712				new_argv[j++] = buf + used;
1713				used += ret + 1;
1714			}
1715			continue;
1716		}
1717
1718		if (str_has_prefix(argv[i], "$arg")) {
1719			char *type = NULL;
1720
1721			n = simple_strtoul(argv[i] + 4, &type, 10);
1722			if (type && !(*type == ':' || *type == '\0')) {
1723				trace_probe_log_err(0, BAD_VAR);
1724				ret = -ENOENT;
1725				goto error;
1726			}
1727			/* Note: $argN starts from $arg1 */
1728			ret = sprint_nth_btf_arg(n - 1, type, buf + used,
1729						 bufsize - used, ctx);
1730			if (ret < 0)
1731				goto error;
1732			new_argv[j++] = buf + used;
1733			used += ret + 1;
1734		} else
1735			new_argv[j++] = argv[i];
1736	}
1737
1738	return new_argv;
1739
1740error:
1741	kfree(new_argv);
1742	return ERR_PTR(ret);
1743}
1744
1745/* @buf: *buf must be equal to NULL. Caller must to free *buf */
1746int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)
1747{
1748	int i, used, ret;
1749	const int bufsize = MAX_DENTRY_ARGS_LEN;
1750	char *tmpbuf = NULL;
1751
1752	if (*buf)
1753		return -EINVAL;
1754
1755	used = 0;
1756	for (i = 0; i < argc; i++) {
1757		char *tmp;
1758		char *equal;
1759		size_t arg_len;
1760
1761		if (!glob_match("*:%p[dD]", argv[i]))
1762			continue;
1763
1764		if (!tmpbuf) {
1765			tmpbuf = kmalloc(bufsize, GFP_KERNEL);
1766			if (!tmpbuf)
1767				return -ENOMEM;
1768		}
1769
1770		tmp = kstrdup(argv[i], GFP_KERNEL);
1771		if (!tmp)
1772			goto nomem;
1773
1774		equal = strchr(tmp, '=');
1775		if (equal)
1776			*equal = '\0';
1777		arg_len = strlen(argv[i]);
1778		tmp[arg_len - 4] = '\0';
1779		if (argv[i][arg_len - 1] == 'd')
1780			ret = snprintf(tmpbuf + used, bufsize - used,
1781				       "%s%s+0x0(+0x%zx(%s)):string",
1782				       equal ? tmp : "", equal ? "=" : "",
1783				       offsetof(struct dentry, d_name.name),
1784				       equal ? equal + 1 : tmp);
1785		else
1786			ret = snprintf(tmpbuf + used, bufsize - used,
1787				       "%s%s+0x0(+0x%zx(+0x%zx(%s))):string",
1788				       equal ? tmp : "", equal ? "=" : "",
1789				       offsetof(struct dentry, d_name.name),
1790				       offsetof(struct file, f_path.dentry),
1791				       equal ? equal + 1 : tmp);
1792
1793		kfree(tmp);
1794		if (ret >= bufsize - used)
1795			goto nomem;
1796		argv[i] = tmpbuf + used;
1797		used += ret + 1;
1798	}
1799
1800	*buf = tmpbuf;
1801	return 0;
1802nomem:
1803	kfree(tmpbuf);
1804	return -ENOMEM;
1805}
1806
1807void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
1808{
1809	clear_btf_context(ctx);
1810}
1811
1812int traceprobe_update_arg(struct probe_arg *arg)
1813{
1814	struct fetch_insn *code = arg->code;
1815	long offset;
1816	char *tmp;
1817	char c;
1818	int ret = 0;
1819
1820	while (code && code->op != FETCH_OP_END) {
1821		if (code->op == FETCH_NOP_SYMBOL) {
1822			if (code[1].op != FETCH_OP_IMM)
1823				return -EINVAL;
1824
1825			tmp = strpbrk(code->data, "+-");
1826			if (tmp)
1827				c = *tmp;
1828			ret = traceprobe_split_symbol_offset(code->data,
1829							     &offset);
1830			if (ret)
1831				return ret;
1832
1833			code[1].immediate =
1834				(unsigned long)kallsyms_lookup_name(code->data);
1835			if (tmp)
1836				*tmp = c;
1837			if (!code[1].immediate)
1838				return -ENOENT;
1839			code[1].immediate += offset;
1840		}
1841		code++;
1842	}
1843	return 0;
1844}
1845
1846/* When len=0, we just calculate the needed length */
1847#define LEN_OR_ZERO (len ? len - pos : 0)
1848static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
1849			   enum probe_print_type ptype)
1850{
1851	struct probe_arg *parg;
1852	int i, j;
1853	int pos = 0;
1854	const char *fmt, *arg;
1855
1856	switch (ptype) {
1857	case PROBE_PRINT_NORMAL:
1858		fmt = "(%lx)";
1859		arg = ", REC->" FIELD_STRING_IP;
1860		break;
1861	case PROBE_PRINT_RETURN:
1862		fmt = "(%lx <- %lx)";
1863		arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1864		break;
1865	case PROBE_PRINT_EVENT:
1866		fmt = "";
1867		arg = "";
1868		break;
1869	default:
1870		WARN_ON_ONCE(1);
1871		return 0;
1872	}
1873
1874	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1875
1876	for (i = 0; i < tp->nr_args; i++) {
1877		parg = tp->args + i;
1878		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
1879		if (parg->count) {
1880			pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
1881					parg->type->fmt);
1882			for (j = 1; j < parg->count; j++)
1883				pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
1884						parg->type->fmt);
1885			pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
1886		} else
1887			pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
1888					parg->type->fmt);
1889	}
1890
1891	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
1892
1893	for (i = 0; i < tp->nr_args; i++) {
1894		parg = tp->args + i;
1895		if (parg->count) {
1896			if (parg->type->is_string)
1897				fmt = ", __get_str(%s[%d])";
1898			else
1899				fmt = ", REC->%s[%d]";
1900			for (j = 0; j < parg->count; j++)
1901				pos += snprintf(buf + pos, LEN_OR_ZERO,
1902						fmt, parg->name, j);
1903		} else {
1904			if (parg->type->is_string)
1905				fmt = ", __get_str(%s)";
1906			else
1907				fmt = ", REC->%s";
1908			pos += snprintf(buf + pos, LEN_OR_ZERO,
1909					fmt, parg->name);
1910		}
1911	}
1912
1913	/* return the length of print_fmt */
1914	return pos;
1915}
1916#undef LEN_OR_ZERO
1917
1918int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
1919{
1920	struct trace_event_call *call = trace_probe_event_call(tp);
1921	int len;
1922	char *print_fmt;
1923
1924	/* First: called with 0 length to calculate the needed length */
1925	len = __set_print_fmt(tp, NULL, 0, ptype);
1926	print_fmt = kmalloc(len + 1, GFP_KERNEL);
1927	if (!print_fmt)
1928		return -ENOMEM;
1929
1930	/* Second: actually write the @print_fmt */
1931	__set_print_fmt(tp, print_fmt, len + 1, ptype);
1932	call->print_fmt = print_fmt;
1933
1934	return 0;
1935}
1936
1937int traceprobe_define_arg_fields(struct trace_event_call *event_call,
1938				 size_t offset, struct trace_probe *tp)
1939{
1940	int ret, i;
1941
1942	/* Set argument names as fields */
1943	for (i = 0; i < tp->nr_args; i++) {
1944		struct probe_arg *parg = &tp->args[i];
1945		const char *fmt = parg->type->fmttype;
1946		int size = parg->type->size;
1947
1948		if (parg->fmt)
1949			fmt = parg->fmt;
1950		if (parg->count)
1951			size *= parg->count;
1952		ret = trace_define_field(event_call, fmt, parg->name,
1953					 offset + parg->offset, size,
1954					 parg->type->is_signed,
1955					 FILTER_OTHER);
1956		if (ret)
1957			return ret;
1958	}
1959	return 0;
1960}
1961
1962static void trace_probe_event_free(struct trace_probe_event *tpe)
1963{
1964	kfree(tpe->class.system);
1965	kfree(tpe->call.name);
1966	kfree(tpe->call.print_fmt);
1967	kfree(tpe);
1968}
1969
1970int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
1971{
1972	if (trace_probe_has_sibling(tp))
1973		return -EBUSY;
1974
1975	list_del_init(&tp->list);
1976	trace_probe_event_free(tp->event);
1977
1978	tp->event = to->event;
1979	list_add_tail(&tp->list, trace_probe_probe_list(to));
1980
1981	return 0;
1982}
1983
1984void trace_probe_unlink(struct trace_probe *tp)
1985{
1986	list_del_init(&tp->list);
1987	if (list_empty(trace_probe_probe_list(tp)))
1988		trace_probe_event_free(tp->event);
1989	tp->event = NULL;
1990}
1991
1992void trace_probe_cleanup(struct trace_probe *tp)
1993{
1994	int i;
1995
1996	for (i = 0; i < tp->nr_args; i++)
1997		traceprobe_free_probe_arg(&tp->args[i]);
1998
1999	if (tp->entry_arg) {
2000		kfree(tp->entry_arg->code);
2001		kfree(tp->entry_arg);
2002		tp->entry_arg = NULL;
2003	}
2004
2005	if (tp->event)
2006		trace_probe_unlink(tp);
2007}
2008
2009int trace_probe_init(struct trace_probe *tp, const char *event,
2010		     const char *group, bool alloc_filter, int nargs)
2011{
2012	struct trace_event_call *call;
2013	size_t size = sizeof(struct trace_probe_event);
2014	int ret = 0;
2015
2016	if (!event || !group)
2017		return -EINVAL;
2018
2019	if (alloc_filter)
2020		size += sizeof(struct trace_uprobe_filter);
2021
2022	tp->event = kzalloc(size, GFP_KERNEL);
2023	if (!tp->event)
2024		return -ENOMEM;
2025
2026	INIT_LIST_HEAD(&tp->event->files);
2027	INIT_LIST_HEAD(&tp->event->class.fields);
2028	INIT_LIST_HEAD(&tp->event->probes);
2029	INIT_LIST_HEAD(&tp->list);
2030	list_add(&tp->list, &tp->event->probes);
2031
2032	call = trace_probe_event_call(tp);
2033	call->class = &tp->event->class;
2034	call->name = kstrdup(event, GFP_KERNEL);
2035	if (!call->name) {
2036		ret = -ENOMEM;
2037		goto error;
2038	}
2039
2040	tp->event->class.system = kstrdup(group, GFP_KERNEL);
2041	if (!tp->event->class.system) {
2042		ret = -ENOMEM;
2043		goto error;
2044	}
2045
2046	tp->nr_args = nargs;
2047	/* Make sure pointers in args[] are NULL */
2048	if (nargs)
2049		memset(tp->args, 0, sizeof(tp->args[0]) * nargs);
2050
2051	return 0;
2052
2053error:
2054	trace_probe_cleanup(tp);
2055	return ret;
2056}
2057
2058static struct trace_event_call *
2059find_trace_event_call(const char *system, const char *event_name)
2060{
2061	struct trace_event_call *tp_event;
2062	const char *name;
2063
2064	list_for_each_entry(tp_event, &ftrace_events, list) {
2065		if (!tp_event->class->system ||
2066		    strcmp(system, tp_event->class->system))
2067			continue;
2068		name = trace_event_name(tp_event);
2069		if (!name || strcmp(event_name, name))
2070			continue;
2071		return tp_event;
2072	}
2073
2074	return NULL;
2075}
2076
2077int trace_probe_register_event_call(struct trace_probe *tp)
2078{
2079	struct trace_event_call *call = trace_probe_event_call(tp);
2080	int ret;
2081
2082	lockdep_assert_held(&event_mutex);
2083
2084	if (find_trace_event_call(trace_probe_group_name(tp),
2085				  trace_probe_name(tp)))
2086		return -EEXIST;
2087
2088	ret = register_trace_event(&call->event);
2089	if (!ret)
2090		return -ENODEV;
2091
2092	ret = trace_add_event_call(call);
2093	if (ret)
2094		unregister_trace_event(&call->event);
2095
2096	return ret;
2097}
2098
2099int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
2100{
2101	struct event_file_link *link;
2102
2103	link = kmalloc(sizeof(*link), GFP_KERNEL);
2104	if (!link)
2105		return -ENOMEM;
2106
2107	link->file = file;
2108	INIT_LIST_HEAD(&link->list);
2109	list_add_tail_rcu(&link->list, &tp->event->files);
2110	trace_probe_set_flag(tp, TP_FLAG_TRACE);
2111	return 0;
2112}
2113
2114struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
2115						  struct trace_event_file *file)
2116{
2117	struct event_file_link *link;
2118
2119	trace_probe_for_each_link(link, tp) {
2120		if (link->file == file)
2121			return link;
2122	}
2123
2124	return NULL;
2125}
2126
2127int trace_probe_remove_file(struct trace_probe *tp,
2128			    struct trace_event_file *file)
2129{
2130	struct event_file_link *link;
2131
2132	link = trace_probe_get_file_link(tp, file);
2133	if (!link)
2134		return -ENOENT;
2135
2136	list_del_rcu(&link->list);
2137	kvfree_rcu_mightsleep(link);
2138
2139	if (list_empty(&tp->event->files))
2140		trace_probe_clear_flag(tp, TP_FLAG_TRACE);
2141
2142	return 0;
2143}
2144
2145/*
2146 * Return the smallest index of different type argument (start from 1).
2147 * If all argument types and name are same, return 0.
2148 */
2149int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
2150{
2151	int i;
2152
2153	/* In case of more arguments */
2154	if (a->nr_args < b->nr_args)
2155		return a->nr_args + 1;
2156	if (a->nr_args > b->nr_args)
2157		return b->nr_args + 1;
2158
2159	for (i = 0; i < a->nr_args; i++) {
2160		if ((b->nr_args <= i) ||
2161		    ((a->args[i].type != b->args[i].type) ||
2162		     (a->args[i].count != b->args[i].count) ||
2163		     strcmp(a->args[i].name, b->args[i].name)))
2164			return i + 1;
2165	}
2166
2167	return 0;
2168}
2169
2170bool trace_probe_match_command_args(struct trace_probe *tp,
2171				    int argc, const char **argv)
2172{
2173	char buf[MAX_ARGSTR_LEN + 1];
2174	int i;
2175
2176	if (tp->nr_args < argc)
2177		return false;
2178
2179	for (i = 0; i < argc; i++) {
2180		snprintf(buf, sizeof(buf), "%s=%s",
2181			 tp->args[i].name, tp->args[i].comm);
2182		if (strcmp(buf, argv[i]))
2183			return false;
2184	}
2185	return true;
2186}
2187
2188int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
2189{
2190	int argc = 0, ret = 0;
2191	char **argv;
2192
2193	argv = argv_split(GFP_KERNEL, raw_command, &argc);
2194	if (!argv)
2195		return -ENOMEM;
2196
2197	if (argc)
2198		ret = createfn(argc, (const char **)argv);
2199
2200	argv_free(argv);
2201
2202	return ret;
2203}
2204
2205int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
2206		 u8 *data, void *field)
2207{
2208	void *p;
2209	int i, j;
2210
2211	for (i = 0; i < nr_args; i++) {
2212		struct probe_arg *a = args + i;
2213
2214		trace_seq_printf(s, " %s=", a->name);
2215		if (likely(!a->count)) {
2216			if (!a->type->print(s, data + a->offset, field))
2217				return -ENOMEM;
2218			continue;
2219		}
2220		trace_seq_putc(s, '{');
2221		p = data + a->offset;
2222		for (j = 0; j < a->count; j++) {
2223			if (!a->type->print(s, p, field))
2224				return -ENOMEM;
2225			trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
2226			p += a->type->size;
2227		}
2228	}
2229	return 0;
2230}
2231