Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1980 insertions, 0 deletions

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
new file mode 100644
index 0000000000..4dc74d73fc
--- /dev/null
+++ b/kernel/trace/trace_probe.c
@@ -0,0 +1,1980 @@
+// 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 <linux/bpf.h>
+#include "trace_btf.h"
+
+#include "trace_probe.h"
+
+#undef C
+#define C(a, b)		b
+
+static const char *trace_probe_err_text[] = { ERRORS };
+
+static 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")
+DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
+
+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_STRING);
+	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, 1,
+			    "__data_loc char[]"),
+	__ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
+			    "__data_loc char[]"),
+	__ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 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(char, u8, u8,  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, unsigned long flags)
+{
+	int i;
+
+	/* Reject the symbol/symstr for uprobes */
+	if (type && (flags & TPARG_FL_USER) &&
+	    (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
+		return NULL;
+
+	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", flags);
+		case 16:
+			return find_fetch_type("u16", flags);
+		case 32:
+			return find_fetch_type("u32", flags);
+		case 64:
+			return find_fetch_type("u64", flags);
+		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;
+}
+
+static struct trace_probe_log trace_probe_log;
+
+void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
+{
+	trace_probe_log.subsystem = subsystem;
+	trace_probe_log.argc = argc;
+	trace_probe_log.argv = argv;
+	trace_probe_log.index = 0;
+}
+
+void trace_probe_log_clear(void)
+{
+	memset(&trace_probe_log, 0, sizeof(trace_probe_log));
+}
+
+void trace_probe_log_set_index(int index)
+{
+	trace_probe_log.index = index;
+}
+
+void __trace_probe_log_err(int offset, int err_type)
+{
+	char *command, *p;
+	int i, len = 0, pos = 0;
+
+	if (!trace_probe_log.argv)
+		return;
+
+	/* Recalculate the length and allocate buffer */
+	for (i = 0; i < trace_probe_log.argc; i++) {
+		if (i == trace_probe_log.index)
+			pos = len;
+		len += strlen(trace_probe_log.argv[i]) + 1;
+	}
+	command = kzalloc(len, GFP_KERNEL);
+	if (!command)
+		return;
+
+	if (trace_probe_log.index >= trace_probe_log.argc) {
+		/**
+		 * Set the error position is next to the last arg + space.
+		 * Note that len includes the terminal null and the cursor
+		 * appears at pos + 1.
+		 */
+		pos = len;
+		offset = 0;
+	}
+
+	/* And make a command string from argv array */
+	p = command;
+	for (i = 0; i < trace_probe_log.argc; i++) {
+		len = strlen(trace_probe_log.argv[i]);
+		strcpy(p, trace_probe_log.argv[i]);
+		p[len] = ' ';
+		p += len + 1;
+	}
+	*(p - 1) = '\0';
+
+	tracing_log_err(NULL, trace_probe_log.subsystem, command,
+			trace_probe_err_text, err_type, pos + offset);
+
+	kfree(command);
+}
+
+/* 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;
+}
+
+/* @buf must has MAX_EVENT_NAME_LEN size */
+int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
+				char *buf, int offset)
+{
+	const char *slash, *event = *pevent;
+	int len;
+
+	slash = strchr(event, '/');
+	if (!slash)
+		slash = strchr(event, '.');
+
+	if (slash) {
+		if (slash == event) {
+			trace_probe_log_err(offset, NO_GROUP_NAME);
+			return -EINVAL;
+		}
+		if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
+			trace_probe_log_err(offset, GROUP_TOO_LONG);
+			return -EINVAL;
+		}
+		strscpy(buf, event, slash - event + 1);
+		if (!is_good_system_name(buf)) {
+			trace_probe_log_err(offset, BAD_GROUP_NAME);
+			return -EINVAL;
+		}
+		*pgroup = buf;
+		*pevent = slash + 1;
+		offset += slash - event + 1;
+		event = *pevent;
+	}
+	len = strlen(event);
+	if (len == 0) {
+		if (slash) {
+			*pevent = NULL;
+			return 0;
+		}
+		trace_probe_log_err(offset, NO_EVENT_NAME);
+		return -EINVAL;
+	} else if (len > MAX_EVENT_NAME_LEN) {
+		trace_probe_log_err(offset, EVENT_TOO_LONG);
+		return -EINVAL;
+	}
+	if (!is_good_name(event)) {
+		trace_probe_log_err(offset, BAD_EVENT_NAME);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int parse_trace_event_arg(char *arg, struct fetch_insn *code,
+				 struct traceprobe_parse_context *ctx)
+{
+	struct ftrace_event_field *field;
+	struct list_head *head;
+
+	head = trace_get_fields(ctx->event);
+	list_for_each_entry(field, head, link) {
+		if (!strcmp(arg, field->name)) {
+			code->op = FETCH_OP_TP_ARG;
+			code->data = field;
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+
+#ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
+
+static u32 btf_type_int(const struct btf_type *t)
+{
+	return *(u32 *)(t + 1);
+}
+
+static bool btf_type_is_char_ptr(struct btf *btf, const struct btf_type *type)
+{
+	const struct btf_type *real_type;
+	u32 intdata;
+	s32 tid;
+
+	real_type = btf_type_skip_modifiers(btf, type->type, &tid);
+	if (!real_type)
+		return false;
+
+	if (BTF_INFO_KIND(real_type->info) != BTF_KIND_INT)
+		return false;
+
+	intdata = btf_type_int(real_type);
+	return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
+		&& BTF_INT_BITS(intdata) == 8;
+}
+
+static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type)
+{
+	const struct btf_type *real_type;
+	const struct btf_array *array;
+	u32 intdata;
+	s32 tid;
+
+	if (BTF_INFO_KIND(type->info) != BTF_KIND_ARRAY)
+		return false;
+
+	array = (const struct btf_array *)(type + 1);
+
+	real_type = btf_type_skip_modifiers(btf, array->type, &tid);
+
+	intdata = btf_type_int(real_type);
+	return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
+		&& BTF_INT_BITS(intdata) == 8;
+}
+
+static int check_prepare_btf_string_fetch(char *typename,
+				struct fetch_insn **pcode,
+				struct traceprobe_parse_context *ctx)
+{
+	struct btf *btf = ctx->btf;
+
+	if (!btf || !ctx->last_type)
+		return 0;
+
+	/* char [] does not need any change. */
+	if (btf_type_is_char_array(btf, ctx->last_type))
+		return 0;
+
+	/* char * requires dereference the pointer. */
+	if (btf_type_is_char_ptr(btf, ctx->last_type)) {
+		struct fetch_insn *code = *pcode + 1;
+
+		if (code->op == FETCH_OP_END) {
+			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
+			return -E2BIG;
+		}
+		if (typename[0] == 'u')
+			code->op = FETCH_OP_UDEREF;
+		else
+			code->op = FETCH_OP_DEREF;
+		code->offset = 0;
+		*pcode = code;
+		return 0;
+	}
+	/* Other types are not available for string */
+	trace_probe_log_err(ctx->offset, BAD_TYPE4STR);
+	return -EINVAL;
+}
+
+static const char *fetch_type_from_btf_type(struct btf *btf,
+					const struct btf_type *type,
+					struct traceprobe_parse_context *ctx)
+{
+	u32 intdata;
+
+	/* TODO: const char * could be converted as a string */
+	switch (BTF_INFO_KIND(type->info)) {
+	case BTF_KIND_ENUM:
+		/* enum is "int", so convert to "s32" */
+		return "s32";
+	case BTF_KIND_ENUM64:
+		return "s64";
+	case BTF_KIND_PTR:
+		/* pointer will be converted to "x??" */
+		if (IS_ENABLED(CONFIG_64BIT))
+			return "x64";
+		else
+			return "x32";
+	case BTF_KIND_INT:
+		intdata = btf_type_int(type);
+		if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) {
+			switch (BTF_INT_BITS(intdata)) {
+			case 8:
+				return "s8";
+			case 16:
+				return "s16";
+			case 32:
+				return "s32";
+			case 64:
+				return "s64";
+			}
+		} else {	/* unsigned */
+			switch (BTF_INT_BITS(intdata)) {
+			case 8:
+				return "u8";
+			case 16:
+				return "u16";
+			case 32:
+				return "u32";
+			case 64:
+				return "u64";
+			}
+			/* bitfield, size is encoded in the type */
+			ctx->last_bitsize = BTF_INT_BITS(intdata);
+			ctx->last_bitoffs += BTF_INT_OFFSET(intdata);
+			return "u64";
+		}
+	}
+	/* TODO: support other types */
+
+	return NULL;
+}
+
+static int query_btf_context(struct traceprobe_parse_context *ctx)
+{
+	const struct btf_param *param;
+	const struct btf_type *type;
+	struct btf *btf;
+	s32 nr;
+
+	if (ctx->btf)
+		return 0;
+
+	if (!ctx->funcname)
+		return -EINVAL;
+
+	type = btf_find_func_proto(ctx->funcname, &btf);
+	if (!type)
+		return -ENOENT;
+
+	ctx->btf = btf;
+	ctx->proto = type;
+
+	/* ctx->params is optional, since func(void) will not have params. */
+	nr = 0;
+	param = btf_get_func_param(type, &nr);
+	if (!IS_ERR_OR_NULL(param)) {
+		/* Hide the first 'data' argument of tracepoint */
+		if (ctx->flags & TPARG_FL_TPOINT) {
+			nr--;
+			param++;
+		}
+	}
+
+	if (nr > 0) {
+		ctx->nr_params = nr;
+		ctx->params = param;
+	} else {
+		ctx->nr_params = 0;
+		ctx->params = NULL;
+	}
+
+	return 0;
+}
+
+static void clear_btf_context(struct traceprobe_parse_context *ctx)
+{
+	if (ctx->btf) {
+		btf_put(ctx->btf);
+		ctx->btf = NULL;
+		ctx->proto = NULL;
+		ctx->params = NULL;
+		ctx->nr_params = 0;
+	}
+}
+
+/* Return 1 if the field separater is arrow operator ('->') */
+static int split_next_field(char *varname, char **next_field,
+			    struct traceprobe_parse_context *ctx)
+{
+	char *field;
+	int ret = 0;
+
+	field = strpbrk(varname, ".-");
+	if (field) {
+		if (field[0] == '-' && field[1] == '>') {
+			field[0] = '\0';
+			field += 2;
+			ret = 1;
+		} else if (field[0] == '.') {
+			field[0] = '\0';
+			field += 1;
+		} else {
+			trace_probe_log_err(ctx->offset + field - varname, BAD_HYPHEN);
+			return -EINVAL;
+		}
+		*next_field = field;
+	}
+
+	return ret;
+}
+
+/*
+ * Parse the field of data structure. The @type must be a pointer type
+ * pointing the target data structure type.
+ */
+static int parse_btf_field(char *fieldname, const struct btf_type *type,
+			   struct fetch_insn **pcode, struct fetch_insn *end,
+			   struct traceprobe_parse_context *ctx)
+{
+	struct fetch_insn *code = *pcode;
+	const struct btf_member *field;
+	u32 bitoffs, anon_offs;
+	char *next;
+	int is_ptr;
+	s32 tid;
+
+	do {
+		/* Outer loop for solving arrow operator ('->') */
+		if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) {
+			trace_probe_log_err(ctx->offset, NO_PTR_STRCT);
+			return -EINVAL;
+		}
+		/* Convert a struct pointer type to a struct type */
+		type = btf_type_skip_modifiers(ctx->btf, type->type, &tid);
+		if (!type) {
+			trace_probe_log_err(ctx->offset, BAD_BTF_TID);
+			return -EINVAL;
+		}
+
+		bitoffs = 0;
+		do {
+			/* Inner loop for solving dot operator ('.') */
+			next = NULL;
+			is_ptr = split_next_field(fieldname, &next, ctx);
+			if (is_ptr < 0)
+				return is_ptr;
+
+			anon_offs = 0;
+			field = btf_find_struct_member(ctx->btf, type, fieldname,
+						       &anon_offs);
+			if (!field) {
+				trace_probe_log_err(ctx->offset, NO_BTF_FIELD);
+				return -ENOENT;
+			}
+			/* Add anonymous structure/union offset */
+			bitoffs += anon_offs;
+
+			/* Accumulate the bit-offsets of the dot-connected fields */
+			if (btf_type_kflag(type)) {
+				bitoffs += BTF_MEMBER_BIT_OFFSET(field->offset);
+				ctx->last_bitsize = BTF_MEMBER_BITFIELD_SIZE(field->offset);
+			} else {
+				bitoffs += field->offset;
+				ctx->last_bitsize = 0;
+			}
+
+			type = btf_type_skip_modifiers(ctx->btf, field->type, &tid);
+			if (!type) {
+				trace_probe_log_err(ctx->offset, BAD_BTF_TID);
+				return -EINVAL;
+			}
+
+			ctx->offset += next - fieldname;
+			fieldname = next;
+		} while (!is_ptr && fieldname);
+
+		if (++code == end) {
+			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
+			return -EINVAL;
+		}
+		code->op = FETCH_OP_DEREF;	/* TODO: user deref support */
+		code->offset = bitoffs / 8;
+		*pcode = code;
+
+		ctx->last_bitoffs = bitoffs % 8;
+		ctx->last_type = type;
+	} while (fieldname);
+
+	return 0;
+}
+
+static int parse_btf_arg(char *varname,
+			 struct fetch_insn **pcode, struct fetch_insn *end,
+			 struct traceprobe_parse_context *ctx)
+{
+	struct fetch_insn *code = *pcode;
+	const struct btf_param *params;
+	const struct btf_type *type;
+	char *field = NULL;
+	int i, is_ptr, ret;
+	u32 tid;
+
+	if (WARN_ON_ONCE(!ctx->funcname))
+		return -EINVAL;
+
+	is_ptr = split_next_field(varname, &field, ctx);
+	if (is_ptr < 0)
+		return is_ptr;
+	if (!is_ptr && field) {
+		/* dot-connected field on an argument is not supported. */
+		trace_probe_log_err(ctx->offset + field - varname,
+				    NOSUP_DAT_ARG);
+		return -EOPNOTSUPP;
+	}
+
+	if (ctx->flags & TPARG_FL_RETURN) {
+		if (strcmp(varname, "$retval") != 0) {
+			trace_probe_log_err(ctx->offset, NO_BTFARG);
+			return -ENOENT;
+		}
+		code->op = FETCH_OP_RETVAL;
+		/* Check whether the function return type is not void */
+		if (query_btf_context(ctx) == 0) {
+			if (ctx->proto->type == 0) {
+				trace_probe_log_err(ctx->offset, NO_RETVAL);
+				return -ENOENT;
+			}
+			tid = ctx->proto->type;
+			goto found;
+		}
+		if (field) {
+			trace_probe_log_err(ctx->offset + field - varname,
+					    NO_BTF_ENTRY);
+			return -ENOENT;
+		}
+		return 0;
+	}
+
+	if (!ctx->btf) {
+		ret = query_btf_context(ctx);
+		if (ret < 0 || ctx->nr_params == 0) {
+			trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
+			return PTR_ERR(params);
+		}
+	}
+	params = ctx->params;
+
+	for (i = 0; i < ctx->nr_params; i++) {
+		const char *name = btf_name_by_offset(ctx->btf, params[i].name_off);
+
+		if (name && !strcmp(name, varname)) {
+			code->op = FETCH_OP_ARG;
+			if (ctx->flags & TPARG_FL_TPOINT)
+				code->param = i + 1;
+			else
+				code->param = i;
+			tid = params[i].type;
+			goto found;
+		}
+	}
+	trace_probe_log_err(ctx->offset, NO_BTFARG);
+	return -ENOENT;
+
+found:
+	type = btf_type_skip_modifiers(ctx->btf, tid, &tid);
+	if (!type) {
+		trace_probe_log_err(ctx->offset, BAD_BTF_TID);
+		return -EINVAL;
+	}
+	/* Initialize the last type information */
+	ctx->last_type = type;
+	ctx->last_bitoffs = 0;
+	ctx->last_bitsize = 0;
+	if (field) {
+		ctx->offset += field - varname;
+		return parse_btf_field(field, type, pcode, end, ctx);
+	}
+	return 0;
+}
+
+static const struct fetch_type *find_fetch_type_from_btf_type(
+					struct traceprobe_parse_context *ctx)
+{
+	struct btf *btf = ctx->btf;
+	const char *typestr = NULL;
+
+	if (btf && ctx->last_type)
+		typestr = fetch_type_from_btf_type(btf, ctx->last_type, ctx);
+
+	return find_fetch_type(typestr, ctx->flags);
+}
+
+static int parse_btf_bitfield(struct fetch_insn **pcode,
+			      struct traceprobe_parse_context *ctx)
+{
+	struct fetch_insn *code = *pcode;
+
+	if ((ctx->last_bitsize % 8 == 0) && ctx->last_bitoffs == 0)
+		return 0;
+
+	code++;
+	if (code->op != FETCH_OP_NOP) {
+		trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
+		return -EINVAL;
+	}
+	*pcode = code;
+
+	code->op = FETCH_OP_MOD_BF;
+	code->lshift = 64 - (ctx->last_bitsize + ctx->last_bitoffs);
+	code->rshift = 64 - ctx->last_bitsize;
+	code->basesize = 64 / 8;
+	return 0;
+}
+
+#else
+static void clear_btf_context(struct traceprobe_parse_context *ctx)
+{
+	ctx->btf = NULL;
+}
+
+static int query_btf_context(struct traceprobe_parse_context *ctx)
+{
+	return -EOPNOTSUPP;
+}
+
+static int parse_btf_arg(char *varname,
+			 struct fetch_insn **pcode, struct fetch_insn *end,
+			 struct traceprobe_parse_context *ctx)
+{
+	trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
+	return -EOPNOTSUPP;
+}
+
+static int parse_btf_bitfield(struct fetch_insn **pcode,
+			      struct traceprobe_parse_context *ctx)
+{
+	trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
+	return -EOPNOTSUPP;
+}
+
+#define find_fetch_type_from_btf_type(ctx)		\
+	find_fetch_type(NULL, ctx->flags)
+
+static int check_prepare_btf_string_fetch(char *typename,
+				struct fetch_insn **pcode,
+				struct traceprobe_parse_context *ctx)
+{
+	return 0;
+}
+
+#endif
+
+#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
+
+/* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */
+static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
+			    struct fetch_insn **pcode,
+			    struct fetch_insn *end,
+			    struct traceprobe_parse_context *ctx)
+{
+	struct fetch_insn *code = *pcode;
+	int err = TP_ERR_BAD_VAR;
+	char *arg = orig_arg + 1;
+	unsigned long param;
+	int ret = 0;
+	int len;
+
+	if (ctx->flags & TPARG_FL_TEVENT) {
+		if (code->data)
+			return -EFAULT;
+		ret = parse_trace_event_arg(arg, code, ctx);
+		if (!ret)
+			return 0;
+		if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
+			code->op = FETCH_OP_COMM;
+			return 0;
+		}
+		/* backward compatibility */
+		ctx->offset = 0;
+		goto inval;
+	}
+
+	if (str_has_prefix(arg, "retval")) {
+		if (!(ctx->flags & TPARG_FL_RETURN)) {
+			err = TP_ERR_RETVAL_ON_PROBE;
+			goto inval;
+		}
+		if (!(ctx->flags & TPARG_FL_KERNEL) ||
+		    !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
+			code->op = FETCH_OP_RETVAL;
+			return 0;
+		}
+		return parse_btf_arg(orig_arg, pcode, end, ctx);
+	}
+
+	len = str_has_prefix(arg, "stack");
+	if (len) {
+
+		if (arg[len] == '\0') {
+			code->op = FETCH_OP_STACKP;
+			return 0;
+		}
+
+		if (isdigit(arg[len])) {
+			ret = kstrtoul(arg + len, 10, &param);
+			if (ret)
+				goto inval;
+
+			if ((ctx->flags & TPARG_FL_KERNEL) &&
+			    param > PARAM_MAX_STACK) {
+				err = TP_ERR_BAD_STACK_NUM;
+				goto inval;
+			}
+			code->op = FETCH_OP_STACK;
+			code->param = (unsigned int)param;
+			return 0;
+		}
+		goto inval;
+	}
+
+	if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
+		code->op = FETCH_OP_COMM;
+		return 0;
+	}
+
+#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
+	len = str_has_prefix(arg, "arg");
+	if (len && tparg_is_function_entry(ctx->flags)) {
+		ret = kstrtoul(arg + len, 10, &param);
+		if (ret)
+			goto inval;
+
+		if (!param || param > PARAM_MAX_STACK) {
+			err = TP_ERR_BAD_ARG_NUM;
+			goto inval;
+		}
+
+		code->op = FETCH_OP_ARG;
+		code->param = (unsigned int)param - 1;
+		/*
+		 * The tracepoint probe will probe a stub function, and the
+		 * first parameter of the stub is a dummy and should be ignored.
+		 */
+		if (ctx->flags & TPARG_FL_TPOINT)
+			code->param++;
+		return 0;
+	}
+#endif
+
+inval:
+	__trace_probe_log_err(ctx->offset, err);
+	return -EINVAL;
+}
+
+static int str_to_immediate(char *str, unsigned long *imm)
+{
+	if (isdigit(str[0]))
+		return kstrtoul(str, 0, imm);
+	else if (str[0] == '-')
+		return kstrtol(str, 0, (long *)imm);
+	else if (str[0] == '+')
+		return kstrtol(str + 1, 0, (long *)imm);
+	return -EINVAL;
+}
+
+static int __parse_imm_string(char *str, char **pbuf, int offs)
+{
+	size_t len = strlen(str);
+
+	if (str[len - 1] != '"') {
+		trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
+		return -EINVAL;
+	}
+	*pbuf = kstrndup(str, len - 1, GFP_KERNEL);
+	if (!*pbuf)
+		return -ENOMEM;
+	return 0;
+}
+
+/* Recursive argument parser */
+static int
+parse_probe_arg(char *arg, const struct fetch_type *type,
+		struct fetch_insn **pcode, struct fetch_insn *end,
+		struct traceprobe_parse_context *ctx)
+{
+	struct fetch_insn *code = *pcode;
+	unsigned long param;
+	int deref = FETCH_OP_DEREF;
+	long offset = 0;
+	char *tmp;
+	int ret = 0;
+
+	switch (arg[0]) {
+	case '$':
+		ret = parse_probe_vars(arg, type, pcode, end, ctx);
+		break;
+
+	case '%':	/* named register */
+		if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
+			/* eprobe and fprobe do not handle registers */
+			trace_probe_log_err(ctx->offset, BAD_VAR);
+			break;
+		}
+		ret = regs_query_register_offset(arg + 1);
+		if (ret >= 0) {
+			code->op = FETCH_OP_REG;
+			code->param = (unsigned int)ret;
+			ret = 0;
+		} else
+			trace_probe_log_err(ctx->offset, BAD_REG_NAME);
+		break;
+
+	case '@':	/* memory, file-offset or symbol */
+		if (isdigit(arg[1])) {
+			ret = kstrtoul(arg + 1, 0, &param);
+			if (ret) {
+				trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
+				break;
+			}
+			/* load address */
+			code->op = FETCH_OP_IMM;
+			code->immediate = param;
+		} else if (arg[1] == '+') {
+			/* kprobes don't support file offsets */
+			if (ctx->flags & TPARG_FL_KERNEL) {
+				trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
+				return -EINVAL;
+			}
+			ret = kstrtol(arg + 2, 0, &offset);
+			if (ret) {
+				trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
+				break;
+			}
+
+			code->op = FETCH_OP_FOFFS;
+			code->immediate = (unsigned long)offset;  // imm64?
+		} else {
+			/* uprobes don't support symbols */
+			if (!(ctx->flags & TPARG_FL_KERNEL)) {
+				trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
+				return -EINVAL;
+			}
+			/* Preserve symbol for updating */
+			code->op = FETCH_NOP_SYMBOL;
+			code->data = kstrdup(arg + 1, GFP_KERNEL);
+			if (!code->data)
+				return -ENOMEM;
+			if (++code == end) {
+				trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
+				return -EINVAL;
+			}
+			code->op = FETCH_OP_IMM;
+			code->immediate = 0;
+		}
+		/* These are fetching from memory */
+		if (++code == end) {
+			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
+			return -EINVAL;
+		}
+		*pcode = code;
+		code->op = FETCH_OP_DEREF;
+		code->offset = offset;
+		break;
+
+	case '+':	/* deref memory */
+	case '-':
+		if (arg[1] == 'u') {
+			deref = FETCH_OP_UDEREF;
+			arg[1] = arg[0];
+			arg++;
+		}
+		if (arg[0] == '+')
+			arg++;	/* Skip '+', because kstrtol() rejects it. */
+		tmp = strchr(arg, '(');
+		if (!tmp) {
+			trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
+			return -EINVAL;
+		}
+		*tmp = '\0';
+		ret = kstrtol(arg, 0, &offset);
+		if (ret) {
+			trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
+			break;
+		}
+		ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
+		arg = tmp + 1;
+		tmp = strrchr(arg, ')');
+		if (!tmp) {
+			trace_probe_log_err(ctx->offset + strlen(arg),
+					    DEREF_OPEN_BRACE);
+			return -EINVAL;
+		} else {
+			const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags);
+			int cur_offs = ctx->offset;
+
+			*tmp = '\0';
+			ret = parse_probe_arg(arg, t2, &code, end, ctx);
+			if (ret)
+				break;
+			ctx->offset = cur_offs;
+			if (code->op == FETCH_OP_COMM ||
+			    code->op == FETCH_OP_DATA) {
+				trace_probe_log_err(ctx->offset, COMM_CANT_DEREF);
+				return -EINVAL;
+			}
+			if (++code == end) {
+				trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
+				return -EINVAL;
+			}
+			*pcode = code;
+
+			code->op = deref;
+			code->offset = offset;
+			/* Reset the last type if used */
+			ctx->last_type = NULL;
+		}
+		break;
+	case '\\':	/* Immediate value */
+		if (arg[1] == '"') {	/* Immediate string */
+			ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
+			if (ret)
+				break;
+			code->op = FETCH_OP_DATA;
+			code->data = tmp;
+		} else {
+			ret = str_to_immediate(arg + 1, &code->immediate);
+			if (ret)
+				trace_probe_log_err(ctx->offset + 1, BAD_IMM);
+			else
+				code->op = FETCH_OP_IMM;
+		}
+		break;
+	default:
+		if (isalpha(arg[0]) || arg[0] == '_') {	/* BTF variable */
+			if (!tparg_is_function_entry(ctx->flags)) {
+				trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
+				return -EINVAL;
+			}
+			ret = parse_btf_arg(arg, pcode, end, ctx);
+			break;
+		}
+	}
+	if (!ret && code->op == FETCH_OP_NOP) {
+		/* Parsed, but do not find fetch method */
+		trace_probe_log_err(ctx->offset, BAD_FETCH_ARG);
+		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 -EINVAL;
+	*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 */
+static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
+					   struct probe_arg *parg,
+					   struct traceprobe_parse_context *ctx)
+{
+	struct fetch_insn *code, *scode, *tmp = NULL;
+	char *t, *t2, *t3;
+	int ret, len;
+	char *arg;
+
+	arg = kstrdup(argv, GFP_KERNEL);
+	if (!arg)
+		return -ENOMEM;
+
+	ret = -EINVAL;
+	len = strlen(arg);
+	if (len > MAX_ARGSTR_LEN) {
+		trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
+		goto out;
+	} else if (len == 0) {
+		trace_probe_log_err(ctx->offset, NO_ARG_BODY);
+		goto out;
+	}
+
+	ret = -ENOMEM;
+	parg->comm = kstrdup(arg, GFP_KERNEL);
+	if (!parg->comm)
+		goto out;
+
+	ret = -EINVAL;
+	t = strchr(arg, ':');
+	if (t) {
+		*t = '\0';
+		t2 = strchr(++t, '[');
+		if (t2) {
+			*t2++ = '\0';
+			t3 = strchr(t2, ']');
+			if (!t3) {
+				int offs = t2 + strlen(t2) - arg;
+
+				trace_probe_log_err(ctx->offset + offs,
+						    ARRAY_NO_CLOSE);
+				goto out;
+			} else if (t3[1] != '\0') {
+				trace_probe_log_err(ctx->offset + t3 + 1 - arg,
+						    BAD_ARRAY_SUFFIX);
+				goto out;
+			}
+			*t3 = '\0';
+			if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
+				trace_probe_log_err(ctx->offset + t2 - arg,
+						    BAD_ARRAY_NUM);
+				goto out;
+			}
+			if (parg->count > MAX_ARRAY_LEN) {
+				trace_probe_log_err(ctx->offset + t2 - arg,
+						    ARRAY_TOO_BIG);
+				goto out;
+			}
+		}
+	}
+
+	/*
+	 * Since $comm and immediate string can not be dereferenced,
+	 * we can find those by strcmp. But ignore for eprobes.
+	 */
+	if (!(ctx->flags & TPARG_FL_TEVENT) &&
+	    (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
+	     strncmp(arg, "\\\"", 2) == 0)) {
+		/* The type of $comm must be "string", and not an array. */
+		if (parg->count || (t && strcmp(t, "string")))
+			goto out;
+		parg->type = find_fetch_type("string", ctx->flags);
+	} else
+		parg->type = find_fetch_type(t, ctx->flags);
+	if (!parg->type) {
+		trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0), BAD_TYPE);
+		goto out;
+	}
+	parg->offset = *size;
+	*size += parg->type->size * (parg->count ?: 1);
+
+	ret = -ENOMEM;
+	if (parg->count) {
+		len = strlen(parg->type->fmttype) + 6;
+		parg->fmt = kmalloc(len, GFP_KERNEL);
+		if (!parg->fmt)
+			goto out;
+		snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
+			 parg->count);
+	}
+
+	code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
+	if (!code)
+		goto out;
+	code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
+
+	ctx->last_type = NULL;
+	ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
+			      ctx);
+	if (ret)
+		goto fail;
+
+	/* Update storing type if BTF is available */
+	if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
+	    ctx->last_type) {
+		if (!t) {
+			parg->type = find_fetch_type_from_btf_type(ctx);
+		} else if (strstr(t, "string")) {
+			ret = check_prepare_btf_string_fetch(t, &code, ctx);
+			if (ret)
+				goto fail;
+		}
+	}
+
+	ret = -EINVAL;
+	/* Store operation */
+	if (parg->type->is_string) {
+		if (!strcmp(parg->type->name, "symstr")) {
+			if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
+			    code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
+			    code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
+				trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
+						    BAD_SYMSTRING);
+				goto fail;
+			}
+		} else {
+			if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
+			    code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
+			    code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
+				trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
+						    BAD_STRING);
+				goto fail;
+			}
+		}
+		if (!strcmp(parg->type->name, "symstr") ||
+		    (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
+		     code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
+		     parg->count) {
+			/*
+			 * IMM, DATA and COMM is pointing actual address, those
+			 * must be kept, and if parg->count != 0, this is an
+			 * array of string pointers instead of string address
+			 * itself.
+			 * For the symstr, it doesn't need to dereference, thus
+			 * it just get the value.
+			 */
+			code++;
+			if (code->op != FETCH_OP_NOP) {
+				trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
+				goto fail;
+			}
+		}
+		/* If op == DEREF, replace it with STRING */
+		if (!strcmp(parg->type->name, "ustring") ||
+		    code->op == FETCH_OP_UDEREF)
+			code->op = FETCH_OP_ST_USTRING;
+		else if (!strcmp(parg->type->name, "symstr"))
+			code->op = FETCH_OP_ST_SYMSTR;
+		else
+			code->op = FETCH_OP_ST_STRING;
+		code->size = parg->type->size;
+		parg->dynamic = true;
+	} else if (code->op == FETCH_OP_DEREF) {
+		code->op = FETCH_OP_ST_MEM;
+		code->size = parg->type->size;
+	} else if (code->op == FETCH_OP_UDEREF) {
+		code->op = FETCH_OP_ST_UMEM;
+		code->size = parg->type->size;
+	} else {
+		code++;
+		if (code->op != FETCH_OP_NOP) {
+			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
+			goto fail;
+		}
+		code->op = FETCH_OP_ST_RAW;
+		code->size = parg->type->size;
+	}
+	scode = code;
+	/* Modify operation */
+	if (t != NULL) {
+		ret = __parse_bitfield_probe_arg(t, parg->type, &code);
+		if (ret) {
+			trace_probe_log_err(ctx->offset + t - arg, BAD_BITFIELD);
+			goto fail;
+		}
+	} else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
+		   ctx->last_type) {
+		ret = parse_btf_bitfield(&code, ctx);
+		if (ret)
+			goto fail;
+	}
+	ret = -EINVAL;
+	/* Loop(Array) operation */
+	if (parg->count) {
+		if (scode->op != FETCH_OP_ST_MEM &&
+		    scode->op != FETCH_OP_ST_STRING &&
+		    scode->op != FETCH_OP_ST_USTRING) {
+			trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0),
+					    BAD_STRING);
+			goto fail;
+		}
+		code++;
+		if (code->op != FETCH_OP_NOP) {
+			trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
+			goto fail;
+		}
+		code->op = FETCH_OP_LP_ARRAY;
+		code->param = parg->count;
+	}
+	code++;
+	code->op = FETCH_OP_END;
+
+	ret = 0;
+	/* Shrink down the code buffer */
+	parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
+	if (!parg->code)
+		ret = -ENOMEM;
+	else
+		memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
+
+fail:
+	if (ret) {
+		for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
+			if (code->op == FETCH_NOP_SYMBOL ||
+			    code->op == FETCH_OP_DATA)
+				kfree(code->data);
+	}
+	kfree(tmp);
+out:
+	kfree(arg);
+
+	return ret;
+}
+
+/* Return 1 if name is reserved or already used by another argument */
+static 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;
+}
+
+static char *generate_probe_arg_name(const char *arg, int idx)
+{
+	char *name = NULL;
+	const char *end;
+
+	/*
+	 * If argument name is omitted, try arg as a name (BTF variable)
+	 * or "argN".
+	 */
+	if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
+		end = strchr(arg, ':');
+		if (!end)
+			end = arg + strlen(arg);
+
+		name = kmemdup_nul(arg, end - arg, GFP_KERNEL);
+		if (!name || !is_good_name(name)) {
+			kfree(name);
+			name = NULL;
+		}
+	}
+
+	if (!name)
+		name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
+
+	return name;
+}
+
+int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
+			       struct traceprobe_parse_context *ctx)
+{
+	struct probe_arg *parg = &tp->args[i];
+	const char *body;
+
+	/* Increment count for freeing args in error case */
+	tp->nr_args++;
+
+	body = strchr(arg, '=');
+	if (body) {
+		if (body - arg > MAX_ARG_NAME_LEN) {
+			trace_probe_log_err(0, ARG_NAME_TOO_LONG);
+			return -EINVAL;
+		} else if (body == arg) {
+			trace_probe_log_err(0, NO_ARG_NAME);
+			return -EINVAL;
+		}
+		parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
+		body++;
+	} else {
+		parg->name = generate_probe_arg_name(arg, i);
+		body = arg;
+	}
+	if (!parg->name)
+		return -ENOMEM;
+
+	if (!is_good_name(parg->name)) {
+		trace_probe_log_err(0, BAD_ARG_NAME);
+		return -EINVAL;
+	}
+	if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
+		trace_probe_log_err(0, USED_ARG_NAME);
+		return -EINVAL;
+	}
+	ctx->offset = body - arg;
+	/* Parse fetch argument */
+	return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);
+}
+
+void traceprobe_free_probe_arg(struct probe_arg *arg)
+{
+	struct fetch_insn *code = arg->code;
+
+	while (code && code->op != FETCH_OP_END) {
+		if (code->op == FETCH_NOP_SYMBOL ||
+		    code->op == FETCH_OP_DATA)
+			kfree(code->data);
+		code++;
+	}
+	kfree(arg->code);
+	kfree(arg->name);
+	kfree(arg->comm);
+	kfree(arg->fmt);
+}
+
+static int argv_has_var_arg(int argc, const char *argv[], int *args_idx,
+			    struct traceprobe_parse_context *ctx)
+{
+	int i, found = 0;
+
+	for (i = 0; i < argc; i++)
+		if (str_has_prefix(argv[i], "$arg")) {
+			trace_probe_log_set_index(i + 2);
+
+			if (!tparg_is_function_entry(ctx->flags)) {
+				trace_probe_log_err(0, NOFENTRY_ARGS);
+				return -EINVAL;
+			}
+
+			if (isdigit(argv[i][4])) {
+				found = 1;
+				continue;
+			}
+
+			if (argv[i][4] != '*') {
+				trace_probe_log_err(0, BAD_VAR);
+				return -EINVAL;
+			}
+
+			if (*args_idx >= 0 && *args_idx < argc) {
+				trace_probe_log_err(0, DOUBLE_ARGS);
+				return -EINVAL;
+			}
+			found = 1;
+			*args_idx = i;
+		}
+
+	return found;
+}
+
+static int sprint_nth_btf_arg(int idx, const char *type,
+			      char *buf, int bufsize,
+			      struct traceprobe_parse_context *ctx)
+{
+	const char *name;
+	int ret;
+
+	if (idx >= ctx->nr_params) {
+		trace_probe_log_err(0, NO_BTFARG);
+		return -ENOENT;
+	}
+	name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off);
+	if (!name) {
+		trace_probe_log_err(0, NO_BTF_ENTRY);
+		return -ENOENT;
+	}
+	ret = snprintf(buf, bufsize, "%s%s", name, type);
+	if (ret >= bufsize) {
+		trace_probe_log_err(0, ARGS_2LONG);
+		return -E2BIG;
+	}
+	return ret;
+}
+
+/* Return new_argv which must be freed after use */
+const char **traceprobe_expand_meta_args(int argc, const char *argv[],
+					 int *new_argc, char *buf, int bufsize,
+					 struct traceprobe_parse_context *ctx)
+{
+	const struct btf_param *params = NULL;
+	int i, j, n, used, ret, args_idx = -1;
+	const char **new_argv = NULL;
+
+	ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	if (!ret) {
+		*new_argc = argc;
+		return NULL;
+	}
+
+	ret = query_btf_context(ctx);
+	if (ret < 0 || ctx->nr_params == 0) {
+		if (args_idx != -1) {
+			/* $arg* requires BTF info */
+			trace_probe_log_err(0, NOSUP_BTFARG);
+			return (const char **)params;
+		}
+		*new_argc = argc;
+		return NULL;
+	}
+
+	if (args_idx >= 0)
+		*new_argc = argc + ctx->nr_params - 1;
+	else
+		*new_argc = argc;
+
+	new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL);
+	if (!new_argv)
+		return ERR_PTR(-ENOMEM);
+
+	used = 0;
+	for (i = 0, j = 0; i < argc; i++) {
+		trace_probe_log_set_index(i + 2);
+		if (i == args_idx) {
+			for (n = 0; n < ctx->nr_params; n++) {
+				ret = sprint_nth_btf_arg(n, "", buf + used,
+							 bufsize - used, ctx);
+				if (ret < 0)
+					goto error;
+
+				new_argv[j++] = buf + used;
+				used += ret + 1;
+			}
+			continue;
+		}
+
+		if (str_has_prefix(argv[i], "$arg")) {
+			char *type = NULL;
+
+			n = simple_strtoul(argv[i] + 4, &type, 10);
+			if (type && !(*type == ':' || *type == '\0')) {
+				trace_probe_log_err(0, BAD_VAR);
+				ret = -ENOENT;
+				goto error;
+			}
+			/* Note: $argN starts from $arg1 */
+			ret = sprint_nth_btf_arg(n - 1, type, buf + used,
+						 bufsize - used, ctx);
+			if (ret < 0)
+				goto error;
+			new_argv[j++] = buf + used;
+			used += ret + 1;
+		} else
+			new_argv[j++] = argv[i];
+	}
+
+	return new_argv;
+
+error:
+	kfree(new_argv);
+	return ERR_PTR(ret);
+}
+
+void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
+{
+	clear_btf_context(ctx);
+}
+
+int traceprobe_update_arg(struct probe_arg *arg)
+{
+	struct fetch_insn *code = arg->code;
+	long offset;
+	char *tmp;
+	char c;
+	int ret = 0;
+
+	while (code && code->op != FETCH_OP_END) {
+		if (code->op == FETCH_NOP_SYMBOL) {
+			if (code[1].op != FETCH_OP_IMM)
+				return -EINVAL;
+
+			tmp = strpbrk(code->data, "+-");
+			if (tmp)
+				c = *tmp;
+			ret = traceprobe_split_symbol_offset(code->data,
+							     &offset);
+			if (ret)
+				return ret;
+
+			code[1].immediate =
+				(unsigned long)kallsyms_lookup_name(code->data);
+			if (tmp)
+				*tmp = c;
+			if (!code[1].immediate)
+				return -ENOENT;
+			code[1].immediate += offset;
+		}
+		code++;
+	}
+	return 0;
+}
+
+/* When len=0, we just calculate the needed length */
+#define LEN_OR_ZERO (len ? len - pos : 0)
+static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
+			   enum probe_print_type ptype)
+{
+	struct probe_arg *parg;
+	int i, j;
+	int pos = 0;
+	const char *fmt, *arg;
+
+	switch (ptype) {
+	case PROBE_PRINT_NORMAL:
+		fmt = "(%lx)";
+		arg = ", REC->" FIELD_STRING_IP;
+		break;
+	case PROBE_PRINT_RETURN:
+		fmt = "(%lx <- %lx)";
+		arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
+		break;
+	case PROBE_PRINT_EVENT:
+		fmt = "";
+		arg = "";
+		break;
+	default:
+		WARN_ON_ONCE(1);
+		return 0;
+	}
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
+
+	for (i = 0; i < tp->nr_args; i++) {
+		parg = tp->args + i;
+		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
+		if (parg->count) {
+			pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
+					parg->type->fmt);
+			for (j = 1; j < parg->count; j++)
+				pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
+						parg->type->fmt);
+			pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
+		} else
+			pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
+					parg->type->fmt);
+	}
+
+	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
+
+	for (i = 0; i < tp->nr_args; i++) {
+		parg = tp->args + i;
+		if (parg->count) {
+			if (parg->type->is_string)
+				fmt = ", __get_str(%s[%d])";
+			else
+				fmt = ", REC->%s[%d]";
+			for (j = 0; j < parg->count; j++)
+				pos += snprintf(buf + pos, LEN_OR_ZERO,
+						fmt, parg->name, j);
+		} else {
+			if (parg->type->is_string)
+				fmt = ", __get_str(%s)";
+			else
+				fmt = ", REC->%s";
+			pos += snprintf(buf + pos, LEN_OR_ZERO,
+					fmt, parg->name);
+		}
+	}
+
+	/* return the length of print_fmt */
+	return pos;
+}
+#undef LEN_OR_ZERO
+
+int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
+{
+	struct trace_event_call *call = trace_probe_event_call(tp);
+	int len;
+	char *print_fmt;
+
+	/* First: called with 0 length to calculate the needed length */
+	len = __set_print_fmt(tp, NULL, 0, ptype);
+	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, ptype);
+	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];
+		const char *fmt = parg->type->fmttype;
+		int size = parg->type->size;
+
+		if (parg->fmt)
+			fmt = parg->fmt;
+		if (parg->count)
+			size *= parg->count;
+		ret = trace_define_field(event_call, fmt, parg->name,
+					 offset + parg->offset, size,
+					 parg->type->is_signed,
+					 FILTER_OTHER);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+static void trace_probe_event_free(struct trace_probe_event *tpe)
+{
+	kfree(tpe->class.system);
+	kfree(tpe->call.name);
+	kfree(tpe->call.print_fmt);
+	kfree(tpe);
+}
+
+int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
+{
+	if (trace_probe_has_sibling(tp))
+		return -EBUSY;
+
+	list_del_init(&tp->list);
+	trace_probe_event_free(tp->event);
+
+	tp->event = to->event;
+	list_add_tail(&tp->list, trace_probe_probe_list(to));
+
+	return 0;
+}
+
+void trace_probe_unlink(struct trace_probe *tp)
+{
+	list_del_init(&tp->list);
+	if (list_empty(trace_probe_probe_list(tp)))
+		trace_probe_event_free(tp->event);
+	tp->event = NULL;
+}
+
+void trace_probe_cleanup(struct trace_probe *tp)
+{
+	int i;
+
+	for (i = 0; i < tp->nr_args; i++)
+		traceprobe_free_probe_arg(&tp->args[i]);
+
+	if (tp->event)
+		trace_probe_unlink(tp);
+}
+
+int trace_probe_init(struct trace_probe *tp, const char *event,
+		     const char *group, bool alloc_filter)
+{
+	struct trace_event_call *call;
+	size_t size = sizeof(struct trace_probe_event);
+	int ret = 0;
+
+	if (!event || !group)
+		return -EINVAL;
+
+	if (alloc_filter)
+		size += sizeof(struct trace_uprobe_filter);
+
+	tp->event = kzalloc(size, GFP_KERNEL);
+	if (!tp->event)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&tp->event->files);
+	INIT_LIST_HEAD(&tp->event->class.fields);
+	INIT_LIST_HEAD(&tp->event->probes);
+	INIT_LIST_HEAD(&tp->list);
+	list_add(&tp->list, &tp->event->probes);
+
+	call = trace_probe_event_call(tp);
+	call->class = &tp->event->class;
+	call->name = kstrdup(event, GFP_KERNEL);
+	if (!call->name) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	tp->event->class.system = kstrdup(group, GFP_KERNEL);
+	if (!tp->event->class.system) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
+	return 0;
+
+error:
+	trace_probe_cleanup(tp);
+	return ret;
+}
+
+static struct trace_event_call *
+find_trace_event_call(const char *system, const char *event_name)
+{
+	struct trace_event_call *tp_event;
+	const char *name;
+
+	list_for_each_entry(tp_event, &ftrace_events, list) {
+		if (!tp_event->class->system ||
+		    strcmp(system, tp_event->class->system))
+			continue;
+		name = trace_event_name(tp_event);
+		if (!name || strcmp(event_name, name))
+			continue;
+		return tp_event;
+	}
+
+	return NULL;
+}
+
+int trace_probe_register_event_call(struct trace_probe *tp)
+{
+	struct trace_event_call *call = trace_probe_event_call(tp);
+	int ret;
+
+	lockdep_assert_held(&event_mutex);
+
+	if (find_trace_event_call(trace_probe_group_name(tp),
+				  trace_probe_name(tp)))
+		return -EEXIST;
+
+	ret = register_trace_event(&call->event);
+	if (!ret)
+		return -ENODEV;
+
+	ret = trace_add_event_call(call);
+	if (ret)
+		unregister_trace_event(&call->event);
+
+	return ret;
+}
+
+int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
+{
+	struct event_file_link *link;
+
+	link = kmalloc(sizeof(*link), GFP_KERNEL);
+	if (!link)
+		return -ENOMEM;
+
+	link->file = file;
+	INIT_LIST_HEAD(&link->list);
+	list_add_tail_rcu(&link->list, &tp->event->files);
+	trace_probe_set_flag(tp, TP_FLAG_TRACE);
+	return 0;
+}
+
+struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
+						  struct trace_event_file *file)
+{
+	struct event_file_link *link;
+
+	trace_probe_for_each_link(link, tp) {
+		if (link->file == file)
+			return link;
+	}
+
+	return NULL;
+}
+
+int trace_probe_remove_file(struct trace_probe *tp,
+			    struct trace_event_file *file)
+{
+	struct event_file_link *link;
+
+	link = trace_probe_get_file_link(tp, file);
+	if (!link)
+		return -ENOENT;
+
+	list_del_rcu(&link->list);
+	kvfree_rcu_mightsleep(link);
+
+	if (list_empty(&tp->event->files))
+		trace_probe_clear_flag(tp, TP_FLAG_TRACE);
+
+	return 0;
+}
+
+/*
+ * Return the smallest index of different type argument (start from 1).
+ * If all argument types and name are same, return 0.
+ */
+int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
+{
+	int i;
+
+	/* In case of more arguments */
+	if (a->nr_args < b->nr_args)
+		return a->nr_args + 1;
+	if (a->nr_args > b->nr_args)
+		return b->nr_args + 1;
+
+	for (i = 0; i < a->nr_args; i++) {
+		if ((b->nr_args <= i) ||
+		    ((a->args[i].type != b->args[i].type) ||
+		     (a->args[i].count != b->args[i].count) ||
+		     strcmp(a->args[i].name, b->args[i].name)))
+			return i + 1;
+	}
+
+	return 0;
+}
+
+bool trace_probe_match_command_args(struct trace_probe *tp,
+				    int argc, const char **argv)
+{
+	char buf[MAX_ARGSTR_LEN + 1];
+	int i;
+
+	if (tp->nr_args < argc)
+		return false;
+
+	for (i = 0; i < argc; i++) {
+		snprintf(buf, sizeof(buf), "%s=%s",
+			 tp->args[i].name, tp->args[i].comm);
+		if (strcmp(buf, argv[i]))
+			return false;
+	}
+	return true;
+}
+
+int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
+{
+	int argc = 0, ret = 0;
+	char **argv;
+
+	argv = argv_split(GFP_KERNEL, raw_command, &argc);
+	if (!argv)
+		return -ENOMEM;
+
+	if (argc)
+		ret = createfn(argc, (const char **)argv);
+
+	argv_free(argv);
+
+	return ret;
+}
+
+int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
+		 u8 *data, void *field)
+{
+	void *p;
+	int i, j;
+
+	for (i = 0; i < nr_args; i++) {
+		struct probe_arg *a = args + i;
+
+		trace_seq_printf(s, " %s=", a->name);
+		if (likely(!a->count)) {
+			if (!a->type->print(s, data + a->offset, field))
+				return -ENOMEM;
+			continue;
+		}
+		trace_seq_putc(s, '{');
+		p = data + a->offset;
+		for (j = 0; j < a->count; j++) {
+			if (!a->type->print(s, p, field))
+				return -ENOMEM;
+			trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
+			p += a->type->size;
+		}
+	}
+	return 0;
+}