[mirror_ubuntu-jammy-kernel.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")

int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
{
	trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
	return !trace_seq_has_overflowed(s);
}
const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";

/* 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_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 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 traceprobe_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
60c2e0ce MH	49	int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq s, void data, void *ent)
	50	{
	51	trace_seq_printf(s, "%pS", (void )(unsigned long *)data);
	52	return !trace_seq_has_overflowed(s);
	53	}
	54	const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
	55
8ab83f56	56	/* Print type function for string type */
56de7630	57	int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq s, void data, void *ent)
8ab83f56 SD	58	{
	59	int len = (u32 )data >> 16;
	60
	61	if (!len)
56de7630	62	trace_seq_puts(s, "(fault)");
8ab83f56	63	else
56de7630	64	trace_seq_printf(s, "\"%s\"",
d2b0191a SRRH	65	(const char *)get_loc_data(data, ent));
d2b0191a SRRH	66	return !trace_seq_has_overflowed(s);
8ab83f56 SD	67	}
8ab83f56 SD	68
b26c74e1	69	const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
8ab83f56	70
f451bc89 MH	71	/* Fetch type information table */
	72	static const struct fetch_type probe_fetch_types[] = {
	73	/* Special types */
	74	__ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1,
	75	"__data_loc char[]"),
	76	/* Basic types */
	77	ASSIGN_FETCH_TYPE(u8, u8, 0),
	78	ASSIGN_FETCH_TYPE(u16, u16, 0),
	79	ASSIGN_FETCH_TYPE(u32, u32, 0),
	80	ASSIGN_FETCH_TYPE(u64, u64, 0),
	81	ASSIGN_FETCH_TYPE(s8, u8, 1),
	82	ASSIGN_FETCH_TYPE(s16, u16, 1),
	83	ASSIGN_FETCH_TYPE(s32, u32, 1),
	84	ASSIGN_FETCH_TYPE(s64, u64, 1),
	85	ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
	86	ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
	87	ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
	88	ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
60c2e0ce	89	ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
f451bc89 MH	90
	91	ASSIGN_FETCH_TYPE_END
	92	};
	93
	94	static const struct fetch_type find_fetch_type(const char type)
8ab83f56 SD	95	{
	96	int i;
	97
	98	if (!type)
	99	type = DEFAULT_FETCH_TYPE_STR;
	100
	101	/* Special case: bitfield */
	102	if (*type == 'b') {
	103	unsigned long bs;
	104
	105	type = strchr(type, '/');
	106	if (!type)
	107	goto fail;
	108
	109	type++;
bcd83ea6	110	if (kstrtoul(type, 0, &bs))
8ab83f56 SD	111	goto fail;
	112
	113	switch (bs) {
	114	case 8:
f451bc89	115	return find_fetch_type("u8");
8ab83f56	116	case 16:
f451bc89	117	return find_fetch_type("u16");
8ab83f56	118	case 32:
f451bc89	119	return find_fetch_type("u32");
8ab83f56	120	case 64:
f451bc89	121	return find_fetch_type("u64");
8ab83f56 SD	122	default:
	123	goto fail;
	124	}
	125	}
	126
f451bc89 MH	127	for (i = 0; probe_fetch_types[i].name; i++) {
	128	if (strcmp(type, probe_fetch_types[i].name) == 0)
	129	return &probe_fetch_types[i];
34fee3a1	130	}
8ab83f56 SD	131
	132	fail:
	133	return NULL;
	134	}
	135
8ab83f56	136	/* Split symbol and offset. */
c5d343b6	137	int traceprobe_split_symbol_offset(char symbol, long offset)
8ab83f56 SD	138	{
	139	char *tmp;
	140	int ret;
	141
	142	if (!offset)
	143	return -EINVAL;
	144
c5d343b6	145	tmp = strpbrk(symbol, "+-");
8ab83f56	146	if (tmp) {
c5d343b6	147	ret = kstrtol(tmp, 0, offset);
8ab83f56 SD	148	if (ret)
8ab83f56 SD	149	return ret;
8ab83f56 SD	150	*tmp = '\0';
	151	} else
	152	*offset = 0;
	153
	154	return 0;
	155	}
	156
	157	#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
	158
	159	static int parse_probe_vars(char arg, const struct fetch_type t,
53305928	160	struct fetch_insn *code, bool is_return,
b079d374	161	bool is_kprobe)
8ab83f56 SD	162	{
	163	int ret = 0;
	164	unsigned long param;
	165
	166	if (strcmp(arg, "retval") == 0) {
	167	if (is_return)
53305928	168	code->op = FETCH_OP_RETVAL;
8ab83f56 SD	169	else
	170	ret = -EINVAL;
	171	} else if (strncmp(arg, "stack", 5) == 0) {
	172	if (arg[5] == '\0') {
53305928	173	code->op = FETCH_OP_STACKP;
8ab83f56	174	} else if (isdigit(arg[5])) {
bcd83ea6	175	ret = kstrtoul(arg + 5, 10, &param);
b079d374	176	if (ret \|\| (is_kprobe && param > PARAM_MAX_STACK))
8ab83f56 SD	177	ret = -EINVAL;
8ab83f56 SD	178	else {
53305928 MH	179	code->op = FETCH_OP_STACK;
53305928 MH	180	code->param = (unsigned int)param;
8ab83f56 SD	181	}
	182	} else
	183	ret = -EINVAL;
35abb67d	184	} else if (strcmp(arg, "comm") == 0) {
53305928	185	code->op = FETCH_OP_COMM;
8ab83f56 SD	186	} else
	187	ret = -EINVAL;
	188
	189	return ret;
	190	}
	191
	192	/* Recursive argument parser */
53305928 MH	193	static int
	194	parse_probe_arg(char arg, const struct fetch_type type,
	195	struct fetch_insn *pcode, struct fetch_insn end,
f451bc89	196	bool is_return, bool is_kprobe)
8ab83f56	197	{
53305928	198	struct fetch_insn code = pcode;
8ab83f56 SD	199	unsigned long param;
	200	long offset;
	201	char *tmp;
34fee3a1	202	int ret = 0;
8ab83f56	203
8ab83f56 SD	204	switch (arg[0]) {
8ab83f56 SD	205	case '$':
53305928 MH	206	ret = parse_probe_vars(arg + 1, type, code,
53305928 MH	207	is_return, is_kprobe);
8ab83f56 SD	208	break;
	209
	210	case '%': /* named register */
	211	ret = regs_query_register_offset(arg + 1);
	212	if (ret >= 0) {
53305928 MH	213	code->op = FETCH_OP_REG;
53305928 MH	214	code->param = (unsigned int)ret;
8ab83f56 SD	215	ret = 0;
	216	}
	217	break;
	218
b7e0bf34	219	case '@': /* memory, file-offset or symbol */
8ab83f56	220	if (isdigit(arg[1])) {
bcd83ea6	221	ret = kstrtoul(arg + 1, 0, &param);
8ab83f56 SD	222	if (ret)
8ab83f56 SD	223	break;
53305928 MH	224	/* load address */
	225	code->op = FETCH_OP_IMM;
	226	code->immediate = param;
b7e0bf34 NK	227	} else if (arg[1] == '+') {
	228	/* kprobes don't support file offsets */
	229	if (is_kprobe)
	230	return -EINVAL;
	231
	232	ret = kstrtol(arg + 2, 0, &offset);
	233	if (ret)
	234	break;
	235
53305928 MH	236	code->op = FETCH_OP_FOFFS;
53305928 MH	237	code->immediate = (unsigned long)offset; // imm64?
8ab83f56	238	} else {
b079d374 NK	239	/* uprobes don't support symbols */
	240	if (!is_kprobe)
	241	return -EINVAL;
	242
8ab83f56 SD	243	ret = traceprobe_split_symbol_offset(arg + 1, &offset);
	244	if (ret)
	245	break;
	246
53305928 MH	247	code->op = FETCH_OP_IMM;
	248	code->immediate =
	249	(unsigned long)kallsyms_lookup_name(arg + 1);
	250	if (!code->immediate)
	251	return -ENOENT;
	252	code->immediate += offset;
8ab83f56	253	}
53305928 MH	254	/* These are fetching from memory */
	255	if (++code == end)
	256	return -E2BIG;
	257	*pcode = code;
	258	code->op = FETCH_OP_DEREF;
	259	code->offset = offset;
8ab83f56 SD	260	break;
	261
	262	case '+': /* deref memory */
bcd83ea6	263	arg++; /* Skip '+', because kstrtol() rejects it. */
8ab83f56 SD	264	case '-':
	265	tmp = strchr(arg, '(');
	266	if (!tmp)
53305928	267	return -EINVAL;
8ab83f56 SD	268
8ab83f56 SD	269	*tmp = '\0';
bcd83ea6	270	ret = kstrtol(arg, 0, &offset);
8ab83f56 SD	271	if (ret)
	272	break;
	273
	274	arg = tmp + 1;
	275	tmp = strrchr(arg, ')');
	276
	277	if (tmp) {
f451bc89	278	const struct fetch_type *t2 = find_fetch_type(NULL);
8ab83f56	279
8ab83f56	280	*tmp = '\0';
53305928	281	ret = parse_probe_arg(arg, t2, &code, end, is_return,
f451bc89	282	is_kprobe);
8ab83f56	283	if (ret)
53305928 MH	284	break;
	285	if (code->op == FETCH_OP_COMM)
	286	return -EINVAL;
	287	if (++code == end)
	288	return -E2BIG;
	289	*pcode = code;
	290
	291	code->op = FETCH_OP_DEREF;
	292	code->offset = offset;
8ab83f56 SD	293	}
	294	break;
	295	}
53305928 MH	296	if (!ret && code->op == FETCH_OP_NOP) {
53305928 MH	297	/* Parsed, but do not find fetch method */
8ab83f56 SD	298	ret = -EINVAL;
8ab83f56 SD	299	}
8ab83f56 SD	300	return ret;
	301	}
	302
	303	#define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
	304
	305	/* Bitfield type needs to be parsed into a fetch function */
	306	static int __parse_bitfield_probe_arg(const char *bf,
	307	const struct fetch_type *t,
53305928	308	struct fetch_insn **pcode)
8ab83f56	309	{
53305928	310	struct fetch_insn code = pcode;
8ab83f56 SD	311	unsigned long bw, bo;
	312	char *tail;
	313
	314	if (*bf != 'b')
	315	return 0;
	316
8ab83f56 SD	317	bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
	318
	319	if (bw == 0 \|\| *tail != '@')
	320	return -EINVAL;
	321
	322	bf = tail + 1;
	323	bo = simple_strtoul(bf, &tail, 0);
	324
	325	if (tail == bf \|\| *tail != '/')
	326	return -EINVAL;
53305928 MH	327	code++;
	328	if (code->op != FETCH_OP_NOP)
	329	return -E2BIG;
	330	*pcode = code;
8ab83f56	331
53305928 MH	332	code->op = FETCH_OP_MOD_BF;
	333	code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
	334	code->rshift = BYTES_TO_BITS(t->size) - bw;
	335	code->basesize = t->size;
8ab83f56 SD	336
	337	return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
	338	}
	339
	340	/* String length checking wrapper */
	341	int traceprobe_parse_probe_arg(char arg, ssize_t size,
f451bc89	342	struct probe_arg *parg, bool is_return, bool is_kprobe)
8ab83f56	343	{
53305928	344	struct fetch_insn code, tmp = NULL;
8ab83f56 SD	345	const char *t;
	346	int ret;
	347
	348	if (strlen(arg) > MAX_ARGSTR_LEN) {
	349	pr_info("Argument is too long.: %s\n", arg);
	350	return -ENOSPC;
	351	}
	352	parg->comm = kstrdup(arg, GFP_KERNEL);
	353	if (!parg->comm) {
	354	pr_info("Failed to allocate memory for command '%s'.\n", arg);
	355	return -ENOMEM;
	356	}
	357	t = strchr(parg->comm, ':');
	358	if (t) {
	359	arg[t - parg->comm] = '\0';
	360	t++;
	361	}
35abb67d OS	362	/*
	363	* The default type of $comm should be "string", and it can't be
	364	* dereferenced.
	365	*/
	366	if (!t && strcmp(arg, "$comm") == 0)
	367	t = "string";
f451bc89	368	parg->type = find_fetch_type(t);
8ab83f56 SD	369	if (!parg->type) {
	370	pr_info("Unsupported type: %s\n", t);
	371	return -EINVAL;
	372	}
	373	parg->offset = *size;
	374	*size += parg->type->size;
8ab83f56	375
53305928 MH	376	code = tmp = kzalloc(sizeof(code) FETCH_INSN_MAX, GFP_KERNEL);
	377	if (!code)
	378	return -ENOMEM;
	379	code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
	380
	381	ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
f451bc89	382	is_return, is_kprobe);
53305928 MH	383	if (ret)
	384	goto fail;
	385
	386	/* Store operation */
	387	if (!strcmp(parg->type->name, "string")) {
	388	if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM &&
	389	code->op != FETCH_OP_COMM) {
	390	pr_info("string only accepts memory or address.\n");
	391	ret = -EINVAL;
	392	goto fail;
	393	}
	394	/* Since IMM or COMM must be the 1st insn, this is safe */
	395	if (code->op == FETCH_OP_IMM \|\| code->op == FETCH_OP_COMM)
	396	code++;
	397	code->op = FETCH_OP_ST_STRING; /* In DEREF case, replace it */
	398	parg->dynamic = true;
	399	} else if (code->op == FETCH_OP_DEREF) {
	400	code->op = FETCH_OP_ST_MEM;
	401	code->size = parg->type->size;
	402	} else {
	403	code++;
	404	if (code->op != FETCH_OP_NOP) {
	405	ret = -E2BIG;
	406	goto fail;
	407	}
	408	code->op = FETCH_OP_ST_RAW;
	409	code->size = parg->type->size;
	410	}
	411	/* Modify operation */
	412	if (t != NULL) {
	413	ret = __parse_bitfield_probe_arg(t, parg->type, &code);
	414	if (ret)
	415	goto fail;
8ab83f56	416	}
53305928 MH	417	code++;
	418	code->op = FETCH_OP_END;
	419
	420	/* Shrink down the code buffer */
	421	parg->code = kzalloc(sizeof(code) (code - tmp + 1), GFP_KERNEL);
	422	if (!parg->code)
	423	ret = -ENOMEM;
	424	else
	425	memcpy(parg->code, tmp, sizeof(code) (code - tmp + 1));
	426
	427	fail:
	428	kfree(tmp);
8ab83f56 SD	429
	430	return ret;
	431	}
	432
	433	/* Return 1 if name is reserved or already used by another argument */
	434	int traceprobe_conflict_field_name(const char *name,
	435	struct probe_arg *args, int narg)
	436	{
	437	int i;
	438
	439	for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
	440	if (strcmp(reserved_field_names[i], name) == 0)
	441	return 1;
	442
	443	for (i = 0; i < narg; i++)
	444	if (strcmp(args[i].name, name) == 0)
	445	return 1;
	446
	447	return 0;
	448	}
	449
8ab83f56 SD	450	void traceprobe_free_probe_arg(struct probe_arg *arg)
8ab83f56 SD	451	{
53305928	452	kfree(arg->code);
8ab83f56 SD	453	kfree(arg->name);
	454	kfree(arg->comm);
	455	}
	456
5bf652aa NK	457	static int __set_print_fmt(struct trace_probe tp, char buf, int len,
	458	bool is_return)
	459	{
	460	int i;
	461	int pos = 0;
	462
	463	const char fmt, arg;
	464
	465	if (!is_return) {
	466	fmt = "(%lx)";
	467	arg = "REC->" FIELD_STRING_IP;
	468	} else {
	469	fmt = "(%lx <- %lx)";
	470	arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
	471	}
	472
	473	/* When len=0, we just calculate the needed length */
	474	#define LEN_OR_ZERO (len ? len - pos : 0)
	475
	476	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
	477
	478	for (i = 0; i < tp->nr_args; i++) {
	479	pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
	480	tp->args[i].name, tp->args[i].type->fmt);
	481	}
	482
	483	pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
	484
	485	for (i = 0; i < tp->nr_args; i++) {
	486	if (strcmp(tp->args[i].type->name, "string") == 0)
	487	pos += snprintf(buf + pos, LEN_OR_ZERO,
	488	", __get_str(%s)",
	489	tp->args[i].name);
	490	else
	491	pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
	492	tp->args[i].name);
	493	}
	494
	495	#undef LEN_OR_ZERO
	496
	497	/* return the length of print_fmt */
	498	return pos;
	499	}
	500
0a46c854	501	int traceprobe_set_print_fmt(struct trace_probe *tp, bool is_return)
5bf652aa NK	502	{
	503	int len;
	504	char *print_fmt;
	505
	506	/* First: called with 0 length to calculate the needed length */
	507	len = __set_print_fmt(tp, NULL, 0, is_return);
	508	print_fmt = kmalloc(len + 1, GFP_KERNEL);
	509	if (!print_fmt)
	510	return -ENOMEM;
	511
	512	/* Second: actually write the @print_fmt */
	513	__set_print_fmt(tp, print_fmt, len + 1, is_return);
	514	tp->call.print_fmt = print_fmt;
	515
	516	return 0;
	517	}
eeb07b06 MH	518
	519	int traceprobe_define_arg_fields(struct trace_event_call *event_call,
	520	size_t offset, struct trace_probe *tp)
	521	{
	522	int ret, i;
	523
	524	/* Set argument names as fields */
	525	for (i = 0; i < tp->nr_args; i++) {
	526	struct probe_arg *parg = &tp->args[i];
	527
	528	ret = trace_define_field(event_call, parg->type->fmttype,
	529	parg->name,
	530	offset + parg->offset,
	531	parg->type->size,
	532	parg->type->is_signed,
	533	FILTER_OTHER);
	534	if (ret)
	535	return ret;
	536	}
	537	return 0;
	538	}