1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
|
// SPDX-License-Identifier: GPL-2.0
/*
* Generic dynamic event control interface
*
* Copyright (C) 2018 Masami Hiramatsu <mhiramat@kernel.org>
*/
#include <linux/debugfs.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/tracefs.h>
#include "trace.h"
#include "trace_dynevent.h"
static DEFINE_MUTEX(dyn_event_ops_mutex);
static LIST_HEAD(dyn_event_ops_list);
int dyn_event_register(struct dyn_event_operations *ops)
{
if (!ops || !ops->create || !ops->show || !ops->is_busy ||
!ops->free || !ops->match)
return -EINVAL;
INIT_LIST_HEAD(&ops->list);
mutex_lock(&dyn_event_ops_mutex);
list_add_tail(&ops->list, &dyn_event_ops_list);
mutex_unlock(&dyn_event_ops_mutex);
return 0;
}
int dyn_event_release(int argc, char **argv, struct dyn_event_operations *type)
{
struct dyn_event *pos, *n;
char *system = NULL, *event, *p;
int ret = -ENOENT;
if (argv[0][0] == '-') {
if (argv[0][1] != ':')
return -EINVAL;
event = &argv[0][2];
} else {
event = strchr(argv[0], ':');
if (!event)
return -EINVAL;
event++;
}
p = strchr(event, '/');
if (p) {
system = event;
event = p + 1;
*p = '\0';
}
if (event[0] == '\0')
return -EINVAL;
mutex_lock(&event_mutex);
for_each_dyn_event_safe(pos, n) {
if (type && type != pos->ops)
continue;
if (pos->ops->match(system, event, pos)) {
ret = pos->ops->free(pos);
break;
}
}
mutex_unlock(&event_mutex);
return ret;
}
static int create_dyn_event(int argc, char **argv)
{
struct dyn_event_operations *ops;
int ret = -ENODEV;
if (argv[0][0] == '-' || argv[0][0] == '!')
return dyn_event_release(argc, argv, NULL);
mutex_lock(&dyn_event_ops_mutex);
list_for_each_entry(ops, &dyn_event_ops_list, list) {
ret = ops->create(argc, (const char **)argv);
if (!ret || ret != -ECANCELED)
break;
}
mutex_unlock(&dyn_event_ops_mutex);
if (ret == -ECANCELED)
ret = -EINVAL;
return ret;
}
/* Protected by event_mutex */
LIST_HEAD(dyn_event_list);
void *dyn_event_seq_start(struct seq_file *m, loff_t *pos)
{
mutex_lock(&event_mutex);
return seq_list_start(&dyn_event_list, *pos);
}
void *dyn_event_seq_next(struct seq_file *m, void *v, loff_t *pos)
{
return seq_list_next(v, &dyn_event_list, pos);
}
void dyn_event_seq_stop(struct seq_file *m, void *v)
{
mutex_unlock(&event_mutex);
}
static int dyn_event_seq_show(struct seq_file *m, void *v)
{
struct dyn_event *ev = v;
if (ev && ev->ops)
return ev->ops->show(m, ev);
return 0;
}
static const struct seq_operations dyn_event_seq_op = {
.start = dyn_event_seq_start,
.next = dyn_event_seq_next,
.stop = dyn_event_seq_stop,
.show = dyn_event_seq_show
};
/*
* dyn_events_release_all - Release all specific events
* @type: the dyn_event_operations * which filters releasing events
*
* This releases all events which ->ops matches @type. If @type is NULL,
* all events are released.
* Return -EBUSY if any of them are in use, and return other errors when
* it failed to free the given event. Except for -EBUSY, event releasing
* process will be aborted at that point and there may be some other
* releasable events on the list.
*/
int dyn_events_release_all(struct dyn_event_operations *type)
{
struct dyn_event *ev, *tmp;
int ret = 0;
mutex_lock(&event_mutex);
for_each_dyn_event(ev) {
if (type && ev->ops != type)
continue;
if (ev->ops->is_busy(ev)) {
ret = -EBUSY;
goto out;
}
}
for_each_dyn_event_safe(ev, tmp) {
if (type && ev->ops != type)
continue;
ret = ev->ops->free(ev);
if (ret)
break;
}
out:
mutex_unlock(&event_mutex);
return ret;
}
static int dyn_event_open(struct inode *inode, struct file *file)
{
int ret;
if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
ret = dyn_events_release_all(NULL);
if (ret < 0)
return ret;
}
return seq_open(file, &dyn_event_seq_op);
}
static ssize_t dyn_event_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
return trace_parse_run_command(file, buffer, count, ppos,
create_dyn_event);
}
static const struct file_operations dynamic_events_ops = {
.owner = THIS_MODULE,
.open = dyn_event_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
.write = dyn_event_write,
};
/* Make a tracefs interface for controlling dynamic events */
static __init int init_dynamic_event(void)
{
struct dentry *d_tracer;
struct dentry *entry;
d_tracer = tracing_init_dentry();
if (IS_ERR(d_tracer))
return 0;
entry = tracefs_create_file("dynamic_events", 0644, d_tracer,
NULL, &dynamic_events_ops);
/* Event list interface */
if (!entry)
pr_warn("Could not create tracefs 'dynamic_events' entry\n");
return 0;
}
fs_initcall(init_dynamic_event);
|
