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("$FreeBSD$");
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#include <sys/sysctl.h>
41#include <sys/sysent.h>
42
43#define KDTRACE_PROC_SIZE	64
44#define	KDTRACE_THREAD_SIZE	256
45
46FEATURE(kdtrace_hooks,
47    "Kernel DTrace hooks which are required to load DTrace kernel modules");
48
49static MALLOC_DEFINE(M_KDTRACE, "kdtrace", "DTrace hooks");
50
51/* Hooks used in the machine-dependent trap handlers. */
52dtrace_trap_func_t		dtrace_trap_func;
53dtrace_doubletrap_func_t	dtrace_doubletrap_func;
54dtrace_pid_probe_ptr_t		dtrace_pid_probe_ptr;
55dtrace_return_probe_ptr_t	dtrace_return_probe_ptr;
56
57systrace_probe_func_t		systrace_probe_func;
58
59/* Return the DTrace process data size compiled in the kernel hooks. */
60size_t
61kdtrace_proc_size()
62{
63
64	return (KDTRACE_PROC_SIZE);
65}
66
67static void
68kdtrace_proc_ctor(void *arg __unused, struct proc *p)
69{
70
71	p->p_dtrace = malloc(KDTRACE_PROC_SIZE, M_KDTRACE, M_WAITOK|M_ZERO);
72}
73
74static void
75kdtrace_proc_dtor(void *arg __unused, struct proc *p)
76{
77
78	if (p->p_dtrace != NULL) {
79		free(p->p_dtrace, M_KDTRACE);
80		p->p_dtrace = NULL;
81	}
82}
83
84/* Return the DTrace thread data size compiled in the kernel hooks. */
85size_t
86kdtrace_thread_size()
87{
88
89	return (KDTRACE_THREAD_SIZE);
90}
91
92static void
93kdtrace_thread_ctor(void *arg __unused, struct thread *td)
94{
95
96	td->td_dtrace = malloc(KDTRACE_THREAD_SIZE, M_KDTRACE, M_WAITOK|M_ZERO);
97}
98
99static void
100kdtrace_thread_dtor(void *arg __unused, struct thread *td)
101{
102
103	if (td->td_dtrace != NULL) {
104		free(td->td_dtrace, M_KDTRACE);
105		td->td_dtrace = NULL;
106	}
107}
108
109/*
110 *  Initialise the kernel DTrace hooks.
111 */
112static void
113init_dtrace(void *dummy __unused)
114{
115
116	EVENTHANDLER_REGISTER(process_ctor, kdtrace_proc_ctor, NULL,
117	    EVENTHANDLER_PRI_ANY);
118	EVENTHANDLER_REGISTER(process_dtor, kdtrace_proc_dtor, NULL,
119	    EVENTHANDLER_PRI_ANY);
120	EVENTHANDLER_REGISTER(thread_ctor, kdtrace_thread_ctor, NULL,
121	    EVENTHANDLER_PRI_ANY);
122	EVENTHANDLER_REGISTER(thread_dtor, kdtrace_thread_dtor, NULL,
123	    EVENTHANDLER_PRI_ANY);
124}
125
126SYSINIT(kdtrace, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_dtrace, NULL);
127