1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Common header file for generic dynamic events.
4 */
5
6#ifndef _TRACE_DYNEVENT_H
7#define _TRACE_DYNEVENT_H
8
9#include <linux/kernel.h>
10#include <linux/list.h>
11#include <linux/mutex.h>
12#include <linux/seq_file.h>
13
14#include "trace.h"
15
16struct dyn_event;
17
18/**
19 * struct dyn_event_operations - Methods for each type of dynamic events
20 *
21 * These methods must be set for each type, since there is no default method.
22 * Before using this for dyn_event_init(), it must be registered by
23 * dyn_event_register().
24 *
25 * @create: Parse and create event method. This is invoked when user passes
26 *  a event definition to dynamic_events interface. This must not destruct
27 *  the arguments and return -ECANCELED if given arguments doesn't match its
28 *  command prefix.
29 * @show: Showing method. This is invoked when user reads the event definitions
30 *  via dynamic_events interface.
31 * @is_busy: Check whether given event is busy so that it can not be deleted.
32 *  Return true if it is busy, otherwise false.
33 * @free: Delete the given event. Return 0 if success, otherwise error.
34 * @match: Check whether given event and system name match this event. The argc
35 *  and argv is used for exact match. Return true if it matches, otherwise
36 *  false.
37 *
38 * Except for @create, these methods are called under holding event_mutex.
39 */
40struct dyn_event_operations {
41	struct list_head	list;
42	int (*create)(const char *raw_command);
43	int (*show)(struct seq_file *m, struct dyn_event *ev);
44	bool (*is_busy)(struct dyn_event *ev);
45	int (*free)(struct dyn_event *ev);
46	bool (*match)(const char *system, const char *event,
47		      int argc, const char **argv, struct dyn_event *ev);
48};
49
50/* Register new dyn_event type -- must be called at first */
51int dyn_event_register(struct dyn_event_operations *ops);
52
53/**
54 * struct dyn_event - Dynamic event list header
55 *
56 * The dyn_event structure encapsulates a list and a pointer to the operators
57 * for making a global list of dynamic events.
58 * User must includes this in each event structure, so that those events can
59 * be added/removed via dynamic_events interface.
60 */
61struct dyn_event {
62	struct list_head		list;
63	struct dyn_event_operations	*ops;
64};
65
66extern struct list_head dyn_event_list;
67
68static inline
69int dyn_event_init(struct dyn_event *ev, struct dyn_event_operations *ops)
70{
71	if (!ev || !ops)
72		return -EINVAL;
73
74	INIT_LIST_HEAD(&ev->list);
75	ev->ops = ops;
76	return 0;
77}
78
79static inline int dyn_event_add(struct dyn_event *ev,
80				struct trace_event_call *call)
81{
82	lockdep_assert_held(&event_mutex);
83
84	if (!ev || !ev->ops)
85		return -EINVAL;
86
87	call->flags |= TRACE_EVENT_FL_DYNAMIC;
88	list_add_tail(&ev->list, &dyn_event_list);
89	return 0;
90}
91
92static inline void dyn_event_remove(struct dyn_event *ev)
93{
94	lockdep_assert_held(&event_mutex);
95	list_del_init(&ev->list);
96}
97
98void *dyn_event_seq_start(struct seq_file *m, loff_t *pos);
99void *dyn_event_seq_next(struct seq_file *m, void *v, loff_t *pos);
100void dyn_event_seq_stop(struct seq_file *m, void *v);
101int dyn_events_release_all(struct dyn_event_operations *type);
102int dyn_event_release(const char *raw_command, struct dyn_event_operations *type);
103
104/*
105 * for_each_dyn_event	-	iterate over the dyn_event list
106 * @pos:	the struct dyn_event * to use as a loop cursor
107 *
108 * This is just a basement of for_each macro. Wrap this for
109 * each actual event structure with ops filtering.
110 */
111#define for_each_dyn_event(pos)	\
112	list_for_each_entry(pos, &dyn_event_list, list)
113
114/*
115 * for_each_dyn_event	-	iterate over the dyn_event list safely
116 * @pos:	the struct dyn_event * to use as a loop cursor
117 * @n:		the struct dyn_event * to use as temporary storage
118 */
119#define for_each_dyn_event_safe(pos, n)	\
120	list_for_each_entry_safe(pos, n, &dyn_event_list, list)
121
122extern void dynevent_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen,
123			      enum dynevent_type type,
124			      dynevent_create_fn_t run_command);
125
126typedef int (*dynevent_check_arg_fn_t)(void *data);
127
128struct dynevent_arg {
129	const char		*str;
130	char			separator; /* e.g. ';', ',', or nothing */
131};
132
133extern void dynevent_arg_init(struct dynevent_arg *arg,
134			      char separator);
135extern int dynevent_arg_add(struct dynevent_cmd *cmd,
136			    struct dynevent_arg *arg,
137			    dynevent_check_arg_fn_t check_arg);
138
139struct dynevent_arg_pair {
140	const char		*lhs;
141	const char		*rhs;
142	char			operator; /* e.g. '=' or nothing */
143	char			separator; /* e.g. ';', ',', or nothing */
144};
145
146extern void dynevent_arg_pair_init(struct dynevent_arg_pair *arg_pair,
147				   char operator, char separator);
148
149extern int dynevent_arg_pair_add(struct dynevent_cmd *cmd,
150				 struct dynevent_arg_pair *arg_pair,
151				 dynevent_check_arg_fn_t check_arg);
152extern int dynevent_str_add(struct dynevent_cmd *cmd, const char *str);
153
154#endif
155