2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2007-2008 John Birrell <jb@FreeBSD.org>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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.
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
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/eventhandler.h>
38 #include <sys/kernel.h>
39 #include <sys/malloc.h>
41 #include <sys/dtrace_bsd.h>
42 #include <sys/sysctl.h>
43 #include <sys/sysent.h>
45 #define KDTRACE_PROC_SIZE 64
46 #define KDTRACE_THREAD_SIZE 256
48 FEATURE(kdtrace_hooks,
49 "Kernel DTrace hooks which are required to load DTrace kernel modules");
51 static MALLOC_DEFINE(M_KDTRACE, "kdtrace", "DTrace hooks");
53 /* Hooks used in the machine-dependent trap handlers. */
54 dtrace_trap_func_t dtrace_trap_func;
55 dtrace_doubletrap_func_t dtrace_doubletrap_func;
56 dtrace_pid_probe_ptr_t dtrace_pid_probe_ptr;
57 dtrace_return_probe_ptr_t dtrace_return_probe_ptr;
59 systrace_probe_func_t __read_frequently systrace_probe_func;
61 /* Return the DTrace process data size compiled in the kernel hooks. */
66 return (KDTRACE_PROC_SIZE);
70 kdtrace_proc_ctor(void *arg __unused, struct proc *p)
73 p->p_dtrace = malloc(KDTRACE_PROC_SIZE, M_KDTRACE, M_WAITOK|M_ZERO);
77 kdtrace_proc_dtor(void *arg __unused, struct proc *p)
80 if (p->p_dtrace != NULL) {
81 free(p->p_dtrace, M_KDTRACE);
86 /* Return the DTrace thread data size compiled in the kernel hooks. */
91 return (KDTRACE_THREAD_SIZE);
95 kdtrace_thread_ctor(void *arg __unused, struct thread *td)
98 td->td_dtrace = malloc(KDTRACE_THREAD_SIZE, M_KDTRACE, M_WAITOK|M_ZERO);
102 kdtrace_thread_dtor(void *arg __unused, struct thread *td)
105 if (td->td_dtrace != NULL) {
106 free(td->td_dtrace, M_KDTRACE);
107 td->td_dtrace = NULL;
112 * Initialise the kernel DTrace hooks.
115 init_dtrace(void *dummy __unused)
118 EVENTHANDLER_REGISTER(process_ctor, kdtrace_proc_ctor, NULL,
119 EVENTHANDLER_PRI_ANY);
120 EVENTHANDLER_REGISTER(process_dtor, kdtrace_proc_dtor, NULL,
121 EVENTHANDLER_PRI_ANY);
122 EVENTHANDLER_REGISTER(thread_ctor, kdtrace_thread_ctor, NULL,
123 EVENTHANDLER_PRI_ANY);
124 EVENTHANDLER_REGISTER(thread_dtor, kdtrace_thread_dtor, NULL,
125 EVENTHANDLER_PRI_ANY);
128 SYSINIT(kdtrace, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_dtrace, NULL);