Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/* probe-example.c
2 *
3 * Connects two functions to marker call sites.
4 *
5 * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
6 *
7 * This file is released under the GPLv2.
8 * See the file COPYING for more details.
9 */
10
11#include <linux/sched.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/marker.h>
15#include <asm/atomic.h>
16
17struct probe_data {
18 const char *name;
19 const char *format;
20 marker_probe_func *probe_func;
21};
22
23void probe_subsystem_event(const struct marker *mdata, void *private,
24 const char *format, ...)
25{
26 va_list ap;
27 /* Declare args */
28 unsigned int value;
29 const char *mystr;
30
31 /* Assign args */
32 va_start(ap, format);
33 value = va_arg(ap, typeof(value));
34 mystr = va_arg(ap, typeof(mystr));
35
36 /* Call printk */
37 printk(KERN_DEBUG "Value %u, string %s\n", value, mystr);
38
39 /* or count, check rights, serialize data in a buffer */
40
41 va_end(ap);
42}
43
44atomic_t eventb_count = ATOMIC_INIT(0);
45
46void probe_subsystem_eventb(const struct marker *mdata, void *private,
47 const char *format, ...)
48{
49 /* Increment counter */
50 atomic_inc(&eventb_count);
51}
52
53static struct probe_data probe_array[] =
54{
55 { .name = "subsystem_event",
56 .format = "integer %d string %s",
57 .probe_func = probe_subsystem_event },
58 { .name = "subsystem_eventb",
59 .format = MARK_NOARGS,
60 .probe_func = probe_subsystem_eventb },
61};
62
63static int __init probe_init(void)
64{
65 int result;
66 int i;
67
68 for (i = 0; i < ARRAY_SIZE(probe_array); i++) {
69 result = marker_probe_register(probe_array[i].name,
70 probe_array[i].format,
71 probe_array[i].probe_func, &probe_array[i]);
72 if (result)
73 printk(KERN_INFO "Unable to register probe %s\n",
74 probe_array[i].name);
75 result = marker_arm(probe_array[i].name);
76 if (result)
77 printk(KERN_INFO "Unable to arm probe %s\n",
78 probe_array[i].name);
79 }
80 return 0;
81}
82
83static void __exit probe_fini(void)
84{
85 int i;
86
87 for (i = 0; i < ARRAY_SIZE(probe_array); i++)
88 marker_probe_unregister(probe_array[i].name);
89 printk(KERN_INFO "Number of event b : %u\n",
90 atomic_read(&eventb_count));
91}
92
93module_init(probe_init);
94module_exit(probe_fini);
95
96MODULE_LICENSE("GPL");
97MODULE_AUTHOR("Mathieu Desnoyers");
98MODULE_DESCRIPTION("SUBSYSTEM Probe");