kern_dtrace.c revision 211614 
1/*-
2 * Copyright (c) 2007-2008 John Birrell <jb@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/sys/kern/kern_dtrace.c 211614 2010-08-22 11:09:53Z rpaulo $");
29
30#include "opt_kdb.h"
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/eventhandler.h>
35#include <sys/kdb.h>
36#include <sys/kernel.h>
37#include <sys/malloc.h>
38#include <sys/proc.h>
39#include <sys/dtrace_bsd.h>
40
41#define KDTRACE_PROC_SIZE	64
42#define	KDTRACE_THREAD_SIZE	256
43
44MALLOC_DEFINE(M_KDTRACE, "kdtrace", "DTrace hooks");
45
46/* Return the DTrace process data size compiled in the kernel hooks. */
47size_t
48kdtrace_proc_size()
49{
50
51	return (KDTRACE_PROC_SIZE);
52}
53
54static void
55kdtrace_proc_ctor(void *arg __unused, struct proc *p)
56{
57
58	p->p_dtrace = malloc(KDTRACE_PROC_SIZE, M_KDTRACE, M_WAITOK|M_ZERO);
59}
60
61static void
62kdtrace_proc_dtor(void *arg __unused, struct proc *p)
63{
64
65	if (p->p_dtrace != NULL) {
66		free(p->p_dtrace, M_KDTRACE);
67		p->p_dtrace = NULL;
68	}
69}
70
71/* Return the DTrace thread data size compiled in the kernel hooks. */
72size_t
73kdtrace_thread_size()
74{
75
76	return (KDTRACE_THREAD_SIZE);
77}
78
79static void
80kdtrace_thread_ctor(void *arg __unused, struct thread *td)
81{
82
83	td->td_dtrace = malloc(KDTRACE_THREAD_SIZE, M_KDTRACE, M_WAITOK|M_ZERO);
84}
85
86static void
87kdtrace_thread_dtor(void *arg __unused, struct thread *td)
88{
89
90	if (td->td_dtrace != NULL) {
91		free(td->td_dtrace, M_KDTRACE);
92		td->td_dtrace = NULL;
93	}
94}
95
96/*
97 *  Initialise the kernel DTrace hooks.
98 */
99static void
100init_dtrace(void *dummy __unused)
101{
102
103	EVENTHANDLER_REGISTER(process_ctor, kdtrace_proc_ctor, NULL,
104	    EVENTHANDLER_PRI_ANY);
105	EVENTHANDLER_REGISTER(process_dtor, kdtrace_proc_dtor, NULL,
106	    EVENTHANDLER_PRI_ANY);
107	EVENTHANDLER_REGISTER(thread_ctor, kdtrace_thread_ctor, NULL,
108	    EVENTHANDLER_PRI_ANY);
109	EVENTHANDLER_REGISTER(thread_dtor, kdtrace_thread_dtor, NULL,
110	    EVENTHANDLER_PRI_ANY);
111}
112
113SYSINIT(kdtrace, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_dtrace, NULL);
114