[linux-block.git] / kernel / trace / trace_probe.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Common code for probe-based Dynamic events.
 *
 * This code was copied from kernel/trace/trace_kprobe.c written by
 * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
 *
 * Updates to make this generic:
 * Copyright (C) IBM Corporation, 2010-2011
 * Author:     Srikar Dronamraju
 */
#define pr_fmt(fmt)	"trace_probe: " fmt

#include "trace_probe.h"

const char *reserved_field_names[] = {
	"common_type",
	"common_flags",
	"common_preempt_count",
	"common_pid",
	"common_tgid",
	FIELD_STRING_IP,
	FIELD_STRING_RETIP,
	FIELD_STRING_FUNC,
};

/* Printing  in basic type function template */
#define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt)			\
int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
{									\
	trace_seq_printf(s, fmt, *(type *)data);			\
	return !trace_seq_has_overflowed(s);				\
}									\
const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;

DEFINE_BASIC_PRINT_TYPE_FUNC(u8,  u8,  "%u")
DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  s8,  "%d")
DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")

/* Print type function for string type */
int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
{
	int len = *(u32 *)data >> 16;

	if (!len)
		trace_seq_puts(s, "(fault)");
	else
		trace_seq_printf(s, "\"%s\"",
				 (const char *)get_loc_data(data, ent));
	return !trace_seq_has_overflowed(s);
}

const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";

/* Fetch type information table */
static const struct fetch_type probe_fetch_types[] = {
	/* Special types */
	__ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1,
			    "__data_loc char[]"),
	/* Basic types */
	ASSIGN_FETCH_TYPE(u8,  u8,  0),
	ASSIGN_FETCH_TYPE(u16, u16, 0),
	ASSIGN_FETCH_TYPE(u32, u32, 0),
	ASSIGN_FETCH_TYPE(u64, u64, 0),
	ASSIGN_FETCH_TYPE(s8,  u8,  1),
	ASSIGN_FETCH_TYPE(s16, u16, 1),
	ASSIGN_FETCH_TYPE(s32, u32, 1),
	ASSIGN_FETCH_TYPE(s64, u64, 1),
	ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
	ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
	ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
	ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),

	ASSIGN_FETCH_TYPE_END
};

static const struct fetch_type *find_fetch_type(const char *type)
{
	int i;

	if (!type)
		type = DEFAULT_FETCH_TYPE_STR;

	/* Special case: bitfield */
	if (*type == 'b') {
		unsigned long bs;

		type = strchr(type, '/');
		if (!type)
			goto fail;

		type++;
		if (kstrtoul(type, 0, &bs))
			goto fail;

		switch (bs) {
		case 8:
			return find_fetch_type("u8");
		case 16:
			return find_fetch_type("u16");
		case 32:
			return find_fetch_type("u32");
		case 64:
			return find_fetch_type("u64");
		default:
			goto fail;
		}
	}

	for (i = 0; probe_fetch_types[i].name; i++) {
		if (strcmp(type, probe_fetch_types[i].name) == 0)
			return &probe_fetch_types[i];
	}

fail:
	return NULL;
}

/* Split symbol and offset. */
int traceprobe_split_symbol_offset(char *symbol, long *offset)
{
	char *tmp;
	int ret;

	if (!offset)
		return -EINVAL;

	tmp = strpbrk(symbol, "+-");
	if (tmp) {
		ret = kstrtol(tmp, 0, offset);
		if (ret)
			return ret;
		*tmp = '\0';
	} else
		*offset = 0;

	return 0;
}

#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))

static int parse_probe_vars(char *arg, const struct fetch_type *t,
			    struct fetch_insn *code, bool is_return,
			    bool is_kprobe)
{
	int ret = 0;
	unsigned long param;

	if (strcmp(arg, "retval") == 0) {
		if (is_return)
			code->op = FETCH_OP_RETVAL;
		else
			ret = -EINVAL;
	} else if (strncmp(arg, "stack", 5) == 0) {
		if (arg[5] == '\0') {
			code->op = FETCH_OP_STACKP;
		} else if (isdigit(arg[5])) {
			ret = kstrtoul(arg + 5, 10, &param);
			if (ret || (is_kprobe && param > PARAM_MAX_STACK))
				ret = -EINVAL;
			else {
				code->op = FETCH_OP_STACK;
				code->param = (unsigned int)param;
			}
		} else
			ret = -EINVAL;
	} else if (strcmp(arg, "comm") == 0) {
		code->op = FETCH_OP_COMM;
	} else
		ret = -EINVAL;

	return ret;
}

/* Recursive argument parser */
static int
parse_probe_arg(char *arg, const struct fetch_type *type,
		struct fetch_insn **pcode, struct fetch_insn *end,
		bool is_return, bool is_kprobe)
{
	struct fetch_insn *code = *pcode;
	unsigned long param;
	long offset;
	char *tmp;
	int ret = 0;

	switch (arg[0]) {
	case '$':
		ret = parse_probe_vars(arg + 1, type, code,
					is_return, is_kprobe);
		break;

	case '%':	/* named register */
		ret = regs_query_register_offset(arg + 1);
		if (ret >= 0) {
			code->op = FETCH_OP_REG;
			code->param = (unsigned int)ret;
			ret = 0;
		}
		break;

	case '@':	/* memory, file-offset or symbol */
		if (isdigit(arg[1])) {
			ret = kstrtoul(arg + 1, 0, &param);
			if (ret)
				break;
			/* load address */
			code->op = FETCH_OP_IMM;
			code->immediate = param;
		} else if (arg[1] == '+') {
			/* kprobes don't support file offsets */
			if (is_kprobe)
				return -EINVAL;

			ret = kstrtol(arg + 2, 0, &offset);
			if (ret)
				break;

			code->op = FETCH_OP_FOFFS;
			code->immediate = (unsigned long)offset;  // imm64?
		} else {
			/* uprobes don't support symbols */
			if (!is_kprobe)
				return -EINVAL;

			ret = traceprobe_split_symbol_offset(arg + 1, &offset);
			if (ret)
				break;

			code->op = FETCH_OP_IMM;
			code->immediate =
				(unsigned long)kallsyms_lookup_name(arg + 1);
			if (!code->immediate)
				return -ENOENT;
			code->immediate += offset;
		}
		/* These are fetching from memory */
		if (++code == end)
			return -E2BIG;
		*pcode = code;
		code->op = FETCH_OP_DEREF;
		code->offset = offset;
		break;

	case '+':	/* deref memory */
		arg++;	/* Skip '+', because kstrtol() rejects it. */
	case '-':
		tmp = strchr(arg, '(');
		if (!tmp)
			return -EINVAL;

		*tmp = '\0';
		ret = kstrtol(arg, 0, &offset);
		if (ret)
			break;

		arg = tmp + 1;
		tmp = strrchr(arg, ')');

		if (tmp) {
			const struct fetch_type *t2 = find_fetch_type(NULL);

			*tmp = '\0';
			ret = parse_probe_arg(arg, t2, &code, end, is_return,
					      is_kprobe);
			if (ret)
				break;
			if (code->op == FETCH_OP_COMM)
				return -EINVAL;
			if (++code == end)
				return -E2BIG;
			*pcode = code;

			code->op = FETCH_OP_DEREF;
			code->offset = offset;
		}
		break;
	}
	if (!ret && code->op == FETCH_OP_NOP) {
		/* Parsed, but do not find fetch method */
		ret = -EINVAL;
	}
	return ret;
}

#define BYTES_TO_BITS(nb)	((BITS_PER_LONG * (nb)) / sizeof(long))

/* Bitfield type needs to be parsed into a fetch function */
static int __parse_bitfield_probe_arg(const char *bf,
				      const struct fetch_type *t,
				      struct fetch_insn **pcode)
{
	struct fetch_insn *code = *pcode;
	unsigned long bw, bo;
	char *tail;

	if (*bf != 'b')
		return 0;

	bw = simple_strtoul(bf + 1, &tail, 0);	/* Use simple one */

	if (bw == 0 || *tail != '@')
		return -EINVAL;

	bf = tail + 1;
	bo = simple_strtoul(bf, &tail, 0);

	if (tail == bf || *tail != '/')
		return -EINVAL;
	code++;
	if (code->op != FETCH_OP_NOP)
		return -E2BIG;
	*pcode = code;

	code->op = FETCH_OP_MOD_BF;
	code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
	code->rshift = BYTES_TO_BITS(t->size) - bw;
	code->basesize = t->size;

	return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
}

/* String length checking wrapper */
int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
		struct probe_arg *parg, bool is_return, bool is_kprobe)
{
	struct fetch_insn *code, *tmp = NULL;
	const char *t;
	int ret;

	if (strlen(arg) > MAX_ARGSTR_LEN) {
		pr_info("Argument is too long.: %s\n",  arg);
		return -ENOSPC;
	}
	parg->comm = kstrdup(arg, GFP_KERNEL);
	if (!parg->comm) {
		pr_info("Failed to allocate memory for command '%s'.\n", arg);
		return -ENOMEM;
	}
	t = strchr(parg->comm, ':');
	if (t) {
		arg[t - parg->comm] = '\0';
		t++;
	}
	/*
	 * The default type of $comm should be "string", and it can't be
	 * dereferenced.
	 */
	if (!t && strcmp(arg, "$comm") == 0)
		t = "string";
	parg->type = find_fetch_type(t);
	if (!parg->type) {
		pr_info("Unsupported type: %s\n", t);
		return -EINVAL;
	}
	parg->offset = *size;
	*size += parg->type->size;

	code = tmp = kzalloc(sizeof(*code) * FETCH_INSN_MAX, GFP_KERNEL);
	if (!code)
		return -ENOMEM;
	code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;

	ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
			      is_return, is_kprobe);
	if (ret)
		goto fail;

	/* Store operation */
	if (!strcmp(parg->type->name, "string")) {
		if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM &&
		    code->op != FETCH_OP_COMM) {
			pr_info("string only accepts memory or address.\n");
			ret = -EINVAL;
			goto fail;
		}
		/* Since IMM or COMM must be the 1st insn, this is safe */
		if (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM)
			code++;
		code->op = FETCH_OP_ST_STRING;	/* In DEREF case, replace it */
		parg->dynamic = true;
	} else if (code->op == FETCH_OP_DEREF) {
		code->op = FETCH_OP_ST_MEM;
		code->size = parg->type->size;
	} else {
		code++;
		if (code->op != FETCH_OP_NOP) {
			ret = -E2BIG;
			goto fail;
		}
		code->op = FETCH_OP_ST_RAW;
		code->size = parg->type->size;
	}
	/* Modify operation */
	if (t != NULL) {
		ret = __parse_bitfield_probe_arg(t, parg->type, &code);
		if (ret)
			goto fail;
	}
	code++;
	code->op = FETCH_OP_END;

	/* Shrink down the code buffer */
	parg->code = kzalloc(sizeof(*code) * (code - tmp + 1), GFP_KERNEL);
	if (!parg->code)
		ret = -ENOMEM;
	else
		memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));

fail:
	kfree(tmp);

	return ret;
}

/* Return 1 if name is reserved or already used by another argument */
int traceprobe_conflict_field_name(const char *name,
			       struct probe_arg *args, int narg)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
		if (strcmp(reserved_field_names[i], name) == 0)
			return 1;

	for (i = 0; i < narg; i++)
		if (strcmp(args[i].name, name) == 0)
			return 1;

	return 0;
}

void traceprobe_free_probe_arg(struct probe_arg *arg)
{
	kfree(arg->code);
	kfree(arg->name);
	kfree(arg->comm);
}

static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
			   bool is_return)
{
	int i;
	int pos = 0;

	const char *fmt, *arg;

	if (!is_return) {
		fmt = "(%lx)";
		arg = "REC->" FIELD_STRING_IP;
	} else {
		fmt = "(%lx <- %lx)";
		arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
	}

	/* When len=0, we just calculate the needed length */
#define LEN_OR_ZERO (len ? len - pos : 0)

	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);

	for (i = 0; i < tp->nr_args; i++) {
		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
				tp->args[i].name, tp->args[i].type->fmt);
	}

	pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);

	for (i = 0; i < tp->nr_args; i++) {
		if (strcmp(tp->args[i].type->name, "string") == 0)
			pos += snprintf(buf + pos, LEN_OR_ZERO,
					", __get_str(%s)",
					tp->args[i].name);
		else
			pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
					tp->args[i].name);
	}

#undef LEN_OR_ZERO

	/* return the length of print_fmt */
	return pos;
}

int set_print_fmt(struct trace_probe *tp, bool is_return)
{
	int len;
	char *print_fmt;

	/* First: called with 0 length to calculate the needed length */
	len = __set_print_fmt(tp, NULL, 0, is_return);
	print_fmt = kmalloc(len + 1, GFP_KERNEL);
	if (!print_fmt)
		return -ENOMEM;

	/* Second: actually write the @print_fmt */
	__set_print_fmt(tp, print_fmt, len + 1, is_return);
	tp->call.print_fmt = print_fmt;

	return 0;
}

int traceprobe_define_arg_fields(struct trace_event_call *event_call,
				 size_t offset, struct trace_probe *tp)
{
	int ret, i;

	/* Set argument names as fields */
	for (i = 0; i < tp->nr_args; i++) {
		struct probe_arg *parg = &tp->args[i];

		ret = trace_define_field(event_call, parg->type->fmttype,
					 parg->name,
					 offset + parg->offset,
					 parg->type->size,
					 parg->type->is_signed,
					 FILTER_OTHER);
		if (ret)
			return ret;
	}
	return 0;
}
Commit	Line	Data
bcea3f96	1	// SPDX-License-Identifier: GPL-2.0
8ab83f56 SD	2	/*
	3	* Common code for probe-based Dynamic events.
	4	*
8ab83f56 SD	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	*/
72576341	12	#define pr_fmt(fmt) "trace_probe: " fmt
8ab83f56 SD	13
	14	#include "trace_probe.h"
	15
	16	const char *reserved_field_names[] = {
	17	"common_type",
	18	"common_flags",
	19	"common_preempt_count",
	20	"common_pid",
	21	"common_tgid",
	22	FIELD_STRING_IP,
	23	FIELD_STRING_RETIP,
	24	FIELD_STRING_FUNC,
	25	};
	26
8ab83f56	27	/* Printing in basic type function template */
17ce3dc7	28	#define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \
56de7630	29	int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq s, void data, void *ent)\
8ab83f56	30	{ \
56de7630	31	trace_seq_printf(s, fmt, (type )data); \
d2b0191a	32	return !trace_seq_has_overflowed(s); \
8ab83f56	33	} \
7bfbc63e	34	const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
8ab83f56	35
bdca79c2 MH	36	DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u")
	37	DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
	38	DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
	39	DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
17ce3dc7 MH	40	DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d")
	41	DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
	42	DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
	43	DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
	44	DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x")
	45	DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
	46	DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
	47	DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
8ab83f56	48
8ab83f56	49	/* Print type function for string type */
56de7630	50	int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq s, void data, void *ent)
8ab83f56 SD	51	{
	52	int len = (u32 )data >> 16;
	53
	54	if (!len)
56de7630	55	trace_seq_puts(s, "(fault)");
8ab83f56	56	else
56de7630	57	trace_seq_printf(s, "\"%s\"",
d2b0191a SRRH	58	(const char *)get_loc_data(data, ent));
d2b0191a SRRH	59	return !trace_seq_has_overflowed(s);
8ab83f56 SD	60	}
8ab83f56 SD	61
b26c74e1	62	const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
8ab83f56	63
f451bc89 MH	64	/* Fetch type information table */
	65	static const struct fetch_type probe_fetch_types[] = {
	66	/* Special types */
	67	__ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1,
	68	"__data_loc char[]"),
	69	/* Basic types */
	70	ASSIGN_FETCH_TYPE(u8, u8, 0),
	71	ASSIGN_FETCH_TYPE(u16, u16, 0),
	72	ASSIGN_FETCH_TYPE(u32, u32, 0),
	73	ASSIGN_FETCH_TYPE(u64, u64, 0),
	74	ASSIGN_FETCH_TYPE(s8, u8, 1),
	75	ASSIGN_FETCH_TYPE(s16, u16, 1),
	76	ASSIGN_FETCH_TYPE(s32, u32, 1),
	77	ASSIGN_FETCH_TYPE(s64, u64, 1),
	78	ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
	79	ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
	80	ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
	81	ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
	82
	83	ASSIGN_FETCH_TYPE_END
	84	};
	85
	86	static const struct fetch_type find_fetch_type(const char type)
8ab83f56 SD	87	{
	88	int i;
	89
	90	if (!type)
	91	type = DEFAULT_FETCH_TYPE_STR;
	92
	93	/* Special case: bitfield */
	94	if (*type == 'b') {
	95	unsigned long bs;
	96
	97	type = strchr(type, '/');
	98	if (!type)
	99	goto fail;
	100
	101	type++;
bcd83ea6	102	if (kstrtoul(type, 0, &bs))
8ab83f56 SD	103	goto fail;
	104
	105	switch (bs) {
	106	case 8:
f451bc89	107	return find_fetch_type("u8");
8ab83f56	108	case 16:
f451bc89	109	return find_fetch_type("u16");
8ab83f56	110	case 32:
f451bc89	111	return find_fetch_type("u32");
8ab83f56	112	case 64:
f451bc89	113	return find_fetch_type("u64");
8ab83f56 SD	114	default:
	115	goto fail;
	116	}
	117	}
	118
f451bc89 MH	119	for (i = 0; probe_fetch_types[i].name; i++) {
	120	if (strcmp(type, probe_fetch_types[i].name) == 0)
	121	return &probe_fetch_types[i];
34fee3a1	122	}
8ab83f56 SD	123
	124	fail:
	125	return NULL;
	126	}
	127
8ab83f56	128	/* Split symbol and offset. */
c5d343b6	129	int traceprobe_split_symbol_offset(char symbol, long offset)
8ab83f56 SD	130	{
	131	char *tmp;
	132	int ret;
	133
	134	if (!offset)
	135	return -EINVAL;
	136
c5d343b6	137	tmp = strpbrk(symbol, "+-");
8ab83f56	138	if (tmp) {
c5d343b6	139	ret = kstrtol(tmp, 0, offset);
8ab83f56 SD	140	if (ret)
8ab83f56 SD	141	return ret;
8ab83f56 SD	142	*tmp = '\0';
	143	} else
	144	*offset = 0;
	145
	146	return 0;
	147	}
	148
	149	#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
	150
	151	static int parse_probe_vars(char arg, const struct fetch_type t,
53305928	152	struct fetch_insn *code, bool is_return,
b079d374	153	bool is_kprobe)
8ab83f56 SD	154	{
	155	int ret = 0;
	156	unsigned long param;
	157
	158	if (strcmp(arg, "retval") == 0) {
	159	if (is_return)
53305928	160	code->op = FETCH_OP_RETVAL;
8ab83f56 SD	161	else
	162	ret = -EINVAL;
	163	} else if (strncmp(arg, "stack", 5) == 0) {
	164	if (arg[5] == '\0') {
53305928	165	code->op = FETCH_OP_STACKP;
8ab83f56	166	} else if (isdigit(arg[5])) {
bcd83ea6	167	ret = kstrtoul(arg + 5, 10, &param);
b079d374	168	if (ret \|\| (is_kprobe && param > PARAM_MAX_STACK))
8ab83f56 SD	169	ret = -EINVAL;
8ab83f56 SD	170	else {
53305928 MH	171	code->op = FETCH_OP_STACK;
53305928 MH	172	code->param = (unsigned int)param;
8ab83f56 SD	173	}
	174	} else
	175	ret = -EINVAL;
35abb67d	176	} else if (strcmp(arg, "comm") == 0) {
53305928	177	code->op = FETCH_OP_COMM;
8ab83f56 SD	178	} else
	179	ret = -EINVAL;
	180
	181	return ret;
	182	}
	183
	184	/* Recursive argument parser */
53305928 MH	185	static int
	186	parse_probe_arg(char arg, const struct fetch_type type,
	187	struct fetch_insn *pcode, struct fetch_insn end,
f451bc89	188	bool is_return, bool is_kprobe)
8ab83f56	189	{
53305928	190	struct fetch_insn code = pcode;
8ab83f56 SD	191	unsigned long param;
	192	long offset;
	193	char *tmp;
34fee3a1	194	int ret = 0;
8ab83f56	195
8ab83f56 SD	196	switch (arg[0]) {
8ab83f56 SD	197	case '$':
53305928 MH	198	ret = parse_probe_vars(arg + 1, type, code,
53305928 MH	199	is_return, is_kprobe);
8ab83f56 SD	200	break;
	201
	202	case '%': /* named register */
	203	ret = regs_query_register_offset(arg + 1);
	204	if (ret >= 0) {
53305928 MH	205	code->op = FETCH_OP_REG;
53305928 MH	206	code->param = (unsigned int)ret;
8ab83f56 SD	207	ret = 0;
	208	}
	209	break;
	210
b7e0bf34	211	case '@': /* memory, file-offset or symbol */
8ab83f56	212	if (isdigit(arg[1])) {
bcd83ea6	213	ret = kstrtoul(arg + 1, 0, &param);
8ab83f56 SD	214	if (ret)
8ab83f56 SD	215	break;
53305928 MH	216	/* load address */
	217	code->op = FETCH_OP_IMM;
	218	code->immediate = param;
b7e0bf34 NK	219	} else if (arg[1] == '+') {
	220	/* kprobes don't support file offsets */
	221	if (is_kprobe)
	222	return -EINVAL;
	223
	224	ret = kstrtol(arg + 2, 0, &offset);
	225	if (ret)
	226	break;
	227
53305928 MH	228	code->op = FETCH_OP_FOFFS;
53305928 MH	229	code->immediate = (unsigned long)offset; // imm64?
8ab83f56	230	} else {
b079d374 NK	231	/* uprobes don't support symbols */
	232	if (!is_kprobe)
	233	return -EINVAL;
	234
8ab83f56 SD	235	ret = traceprobe_split_symbol_offset(arg + 1, &offset);
	236	if (ret)
	237	break;
	238
53305928 MH	239	code->op = FETCH_OP_IMM;
	240	code->immediate =
	241	(unsigned long)kallsyms_lookup_name(arg + 1);
	242	if (!code->immediate)
	243	return -ENOENT;
	244	code->immediate += offset;
8ab83f56	245	}
53305928 MH	246	/* These are fetching from memory */
	247	if (++code == end)
	248	return -E2BIG;
	249	*pcode = code;
	250	code->op = FETCH_OP_DEREF;
	251	code->offset = offset;
8ab83f56 SD	252	break;
	253
	254	case '+': /* deref memory */
bcd83ea6	255	arg++; /* Skip '+', because kstrtol() rejects it. */
8ab83f56 SD	256	case '-':
	257	tmp = strchr(arg, '(');
	258	if (!tmp)
53305928	259	return -EINVAL;
8ab83f56 SD	260
8ab83f56 SD	261	*tmp = '\0';
bcd83ea6	262	ret = kstrtol(arg, 0, &offset);
8ab83f56 SD	263	if (ret)
	264	break;
	265
	266	arg = tmp + 1;
	267	tmp = strrchr(arg, ')');
	268
	269	if (tmp) {
f451bc89	270	const struct fetch_type *t2 = find_fetch_type(NULL);
8ab83f56	271
8ab83f56	272	*tmp = '\0';
53305928	273	ret = parse_probe_arg(arg, t2, &code, end, is_return,
f451bc89	274	is_kprobe);
8ab83f56	275	if (ret)
53305928 MH	276	break;
	277	if (code->op == FETCH_OP_COMM)
	278	return -EINVAL;
	279	if (++code == end)
	280	return -E2BIG;
	281	*pcode = code;
	282
	283	code->op = FETCH_OP_DEREF;
	284	code->offset = offset;
8ab83f56 SD	285	}
	286	break;
	287	}
53305928 MH	288	if (!ret && code->op == FETCH_OP_NOP) {
53305928 MH	289	/* Parsed, but do not find fetch method */
8ab83f56 SD	290	ret = -EINVAL;
8ab83f56 SD	291	}
8ab83f56 SD	292	return ret;
	293	}
	294
	295	#define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
	296
	297	/* Bitfield type needs to be parsed into a fetch function */
	298	static int __parse_bitfield_probe_arg(const char *bf,
	299	const struct fetch_type *t,
53305928	300	struct fetch_insn **pcode)
8ab83f56	301	{
53305928	302	struct fetch_insn code = pcode;
8ab83f56 SD	303	unsigned long bw, bo;
	304	char *tail;
	305
	306	if (*bf != 'b')
	307	return 0;
	308
8ab83f56 SD	309	bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
	310
	311	if (bw == 0 \|\| *tail != '@')
	312	return -EINVAL;
	313
	314	bf = tail + 1;
	315	bo = simple_strtoul(bf, &tail, 0);
	316
	317	if (tail == bf \|\| *tail != '/')
	318	return -EINVAL;
53305928 MH	319	code++;
	320	if (code->op != FETCH_OP_NOP)
	321	return -E2BIG;
	322	*pcode = code;
8ab83f56	323
53305928 MH	324	code->op = FETCH_OP_MOD_BF;
	325	code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
	326	code->rshift = BYTES_TO_BITS(t->size) - bw;
	327	code->basesize = t->size;
8ab83f56 SD	328
	329	return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
	330	}
	331
	332	/* String length checking wrapper */
	333	int traceprobe_parse_probe_arg(char arg, ssize_t size,
f451bc89	334	struct probe_arg *parg, bool is_return, bool is_kprobe)
8ab83f56	335	{
53305928	336	struct fetch_insn code, tmp = NULL;
8ab83f56 SD	337	const char *t;
	338	int ret;
	339
	340	if (strlen(arg) > MAX_ARGSTR_LEN) {
	341	pr_info("Argument is too long.: %s\n", arg);
	342	return -ENOSPC;
	343	}
	344	parg->comm = kstrdup(arg, GFP_KERNEL);
	345	if (!parg->comm) {
	346	pr_info("Failed to allocate memory for command '%s'.\n", arg);
	347	return -ENOMEM;
	348	}
	349	t = strchr(parg->comm, ':');
	350	if (t) {
	351	arg[t - parg->comm] = '\0';
	352	t++;
	353	}
35abb67d OS	354	/*
	355	* The default type of $comm should be "string", and it can't be
	356	* dereferenced.
	357	*/
	358	if (!t && strcmp(arg, "$comm") == 0)
	359	t = "string";
f451bc89	360	parg->type = find_fetch_type(t);
8ab83f56 SD	361	if (!parg->type) {
	362	pr_info("Unsupported type: %s\n", t);
	363	return -EINVAL;
	364	}
	365	parg->offset = *size;
	366	*size += parg->type->size;
8ab83f56	367
53305928 MH	368	code = tmp = kzalloc(sizeof(code) FETCH_INSN_MAX, GFP_KERNEL);
	369	if (!code)
	370	return -ENOMEM;
	371	code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
	372
	373	ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
f451bc89	374	is_return, is_kprobe);
53305928 MH	375	if (ret)
	376	goto fail;
	377
	378	/* Store operation */
	379	if (!strcmp(parg->type->name, "string")) {
	380	if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM &&
	381	code->op != FETCH_OP_COMM) {
	382	pr_info("string only accepts memory or address.\n");
	383	ret = -EINVAL;
	384	goto fail;
	385	}
	386	/* Since IMM or COMM must be the 1st insn, this is safe */
	387	if (code->op == FETCH_OP_IMM \|\| code->op == FETCH_OP_COMM)
	388	code++;
	389	code->op = FETCH_OP_ST_STRING; /* In DEREF case, replace it */
	390	parg->dynamic = true;
	391	} else if (code->op == FETCH_OP_DEREF) {
	392	code->op = FETCH_OP_ST_MEM;
	393	code->size = parg->type->size;
	394	} else {
	395	code++;
	396	if (code->op != FETCH_OP_NOP) {
	397	ret = -E2BIG;
	398	goto fail;
	399	}
	400	code->op = FETCH_OP_ST_RAW;
	401	code->size = parg->type->size;
	402	}
	403	/* Modify operation */
	404	if (t != NULL) {
	405	ret = __parse_bitfield_probe_arg(t, parg->type, &code);
	406	if (ret)
	407	goto fail;
8ab83f56	408	}
53305928 MH	409	code++;
	410	code->op = FETCH_OP_END;
	411
	412	/* Shrink down the code buffer */
	413	parg->code = kzalloc(sizeof(code) (code - tmp + 1), GFP_KERNEL);
	414	if (!parg->code)
	415	ret = -ENOMEM;
	416	else
	417	memcpy(parg->code, tmp, sizeof(code) (code - tmp + 1));
	418
	419	fail:
	420	kfree(tmp);
8ab83f56 SD	421
	422	return ret;
	423	}
	424
	425	/* Return 1 if name is reserved or already used by another argument */
	426	int traceprobe_conflict_field_name(const char *name,
	427	struct probe_arg *args, int narg)
	428	{
	429	int i;
	430
	431	for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
	432	if (strcmp(reserved_field_names[i], name) == 0)
	433	return 1;
	434
	435	for (i = 0; i < narg; i++)
	436	if (strcmp(args[i].name, name) == 0)
	437	return 1;
	438
	439	return 0;
	440	}
	441
8ab83f56 SD	442	void traceprobe_free_probe_arg(struct probe_arg *arg)
8ab83f56 SD	443	{
53305928	444	kfree(arg->code);
8ab83f56 SD	445	kfree(arg->name);
	446	kfree(arg->comm);
	447	}
	448
5bf652aa NK	449	static int __set_print_fmt(struct trace_probe tp, char buf, int len,
	450	bool is_return)
	451	{
	452	int i;
	453	int pos = 0;
	454
	455	const char fmt, arg;
	456
	457	if (!is_return) {
	458	fmt = "(%lx)";
	459	arg = "REC->" FIELD_STRING_IP;
	460	} else {
	461	fmt = "(%lx <- %lx)";
	462	arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
	463	}
	464
	465	/* When len=0, we just calculate the needed length */
	466	#define LEN_OR_ZERO (len ? len - pos : 0)
	467
	468	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
	469
	470	for (i = 0; i < tp->nr_args; i++) {
	471	pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
	472	tp->args[i].name, tp->args[i].type->fmt);
	473	}
	474
	475	pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
	476
	477	for (i = 0; i < tp->nr_args; i++) {
	478	if (strcmp(tp->args[i].type->name, "string") == 0)
	479	pos += snprintf(buf + pos, LEN_OR_ZERO,
	480	", __get_str(%s)",
	481	tp->args[i].name);
	482	else
	483	pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
	484	tp->args[i].name);
	485	}
	486
	487	#undef LEN_OR_ZERO
	488
	489	/* return the length of print_fmt */
	490	return pos;
	491	}
	492
	493	int set_print_fmt(struct trace_probe *tp, bool is_return)
	494	{
	495	int len;
	496	char *print_fmt;
	497
	498	/* First: called with 0 length to calculate the needed length */
	499	len = __set_print_fmt(tp, NULL, 0, is_return);
	500	print_fmt = kmalloc(len + 1, GFP_KERNEL);
	501	if (!print_fmt)
	502	return -ENOMEM;
	503
	504	/* Second: actually write the @print_fmt */
	505	__set_print_fmt(tp, print_fmt, len + 1, is_return);
	506	tp->call.print_fmt = print_fmt;
	507
	508	return 0;
	509	}
eeb07b06 MH	510
	511	int traceprobe_define_arg_fields(struct trace_event_call *event_call,
	512	size_t offset, struct trace_probe *tp)
	513	{
	514	int ret, i;
	515
	516	/* Set argument names as fields */
	517	for (i = 0; i < tp->nr_args; i++) {
	518	struct probe_arg *parg = &tp->args[i];
	519
	520	ret = trace_define_field(event_call, parg->type->fmttype,
	521	parg->name,
	522	offset + parg->offset,
	523	parg->type->size,
	524	parg->type->is_signed,
	525	FILTER_OTHER);
	526	if (ret)
	527	return ret;
	528	}
	529	return 0;
	530	}