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(list: &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(new: &ev->list, head: &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(entry: &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);
103int dyn_event_create(const char *raw_command, struct dyn_event_operations *type);
104
105/*
106 * for_each_dyn_event - iterate over the dyn_event list
107 * @pos: the struct dyn_event * to use as a loop cursor
108 *
109 * This is just a basement of for_each macro. Wrap this for
110 * each actual event structure with ops filtering.
111 */
112#define for_each_dyn_event(pos) \
113 list_for_each_entry(pos, &dyn_event_list, list)
114
115/*
116 * for_each_dyn_event - iterate over the dyn_event list safely
117 * @pos: the struct dyn_event * to use as a loop cursor
118 * @n: the struct dyn_event * to use as temporary storage
119 */
120#define for_each_dyn_event_safe(pos, n) \
121 list_for_each_entry_safe(pos, n, &dyn_event_list, list)
122
123extern void dynevent_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen,
124 enum dynevent_type type,
125 dynevent_create_fn_t run_command);
126
127typedef int (*dynevent_check_arg_fn_t)(void *data);
128
129struct dynevent_arg {
130 const char *str;
131 char separator; /* e.g. ';', ',', or nothing */
132};
133
134extern void dynevent_arg_init(struct dynevent_arg *arg,
135 char separator);
136extern int dynevent_arg_add(struct dynevent_cmd *cmd,
137 struct dynevent_arg *arg,
138 dynevent_check_arg_fn_t check_arg);
139
140struct dynevent_arg_pair {
141 const char *lhs;
142 const char *rhs;
143 char operator; /* e.g. '=' or nothing */
144 char separator; /* e.g. ';', ',', or nothing */
145};
146
147extern void dynevent_arg_pair_init(struct dynevent_arg_pair *arg_pair,
148 char operator, char separator);
149
150extern int dynevent_arg_pair_add(struct dynevent_cmd *cmd,
151 struct dynevent_arg_pair *arg_pair,
152 dynevent_check_arg_fn_t check_arg);
153extern int dynevent_str_add(struct dynevent_cmd *cmd, const char *str);
154
155#endif
156