1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2007-2008 John Birrell <jb@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include "opt_kdb.h"
33
34#include <sys/param.h>
35#include <sys/systm.h>
36#include <sys/eventhandler.h>
37#include <sys/kdb.h>
38#include <sys/kernel.h>
39#include <sys/malloc.h>
40#include <sys/proc.h>
41#include <sys/dtrace_bsd.h>
42#include <sys/sysctl.h>
43#include <sys/sysent.h>
44
45#define KDTRACE_PROC_SIZE	64
46#define	KDTRACE_THREAD_SIZE	256
47
48FEATURE(kdtrace_hooks,
49    "Kernel DTrace hooks which are required to load DTrace kernel modules");
50
51static MALLOC_DEFINE(M_KDTRACE, "kdtrace", "DTrace hooks");
52
53/* Hooks used in the machine-dependent trap handlers. */
54dtrace_trap_func_t		dtrace_trap_func;
55dtrace_doubletrap_func_t	dtrace_doubletrap_func;
56dtrace_pid_probe_ptr_t		dtrace_pid_probe_ptr;
57dtrace_return_probe_ptr_t	dtrace_return_probe_ptr;
58
59bool __read_frequently		systrace_enabled;
60systrace_probe_func_t 		systrace_probe_func;
61
62/* Return the DTrace process data size compiled in the kernel hooks. */
63size_t
64kdtrace_proc_size()
65{
66
67	return (KDTRACE_PROC_SIZE);
68}
69
70static void
71kdtrace_proc_ctor(void *arg __unused, struct proc *p)
72{
73
74	p->p_dtrace = malloc(KDTRACE_PROC_SIZE, M_KDTRACE, M_WAITOK|M_ZERO);
75}
76
77static void
78kdtrace_proc_dtor(void *arg __unused, struct proc *p)
79{
80
81	if (p->p_dtrace != NULL) {
82		free(p->p_dtrace, M_KDTRACE);
83		p->p_dtrace = NULL;
84	}
85}
86
87/* Return the DTrace thread data size compiled in the kernel hooks. */
88size_t
89kdtrace_thread_size()
90{
91
92	return (KDTRACE_THREAD_SIZE);
93}
94
95static void
96kdtrace_thread_ctor(void *arg __unused, struct thread *td)
97{
98
99	td->td_dtrace = malloc(KDTRACE_THREAD_SIZE, M_KDTRACE, M_WAITOK|M_ZERO);
100}
101
102static void
103kdtrace_thread_dtor(void *arg __unused, struct thread *td)
104{
105
106	if (td->td_dtrace != NULL) {
107		free(td->td_dtrace, M_KDTRACE);
108		td->td_dtrace = NULL;
109	}
110}
111
112/*
113 *  Initialise the kernel DTrace hooks.
114 */
115static void
116init_dtrace(void *dummy __unused)
117{
118
119	EVENTHANDLER_REGISTER(process_ctor, kdtrace_proc_ctor, NULL,
120	    EVENTHANDLER_PRI_ANY);
121	EVENTHANDLER_REGISTER(process_dtor, kdtrace_proc_dtor, NULL,
122	    EVENTHANDLER_PRI_ANY);
123	EVENTHANDLER_REGISTER(thread_ctor, kdtrace_thread_ctor, NULL,
124	    EVENTHANDLER_PRI_ANY);
125	EVENTHANDLER_REGISTER(thread_dtor, kdtrace_thread_dtor, NULL,
126	    EVENTHANDLER_PRI_ANY);
127}
128
129SYSINIT(kdtrace, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_dtrace, NULL);
130