kern_dtrace.c revision 227293
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 227293 2011-11-07 06:44:47Z ed $"); 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 42#define KDTRACE_PROC_SIZE 64 43#define KDTRACE_THREAD_SIZE 256 44 45FEATURE(kdtrace_hooks, 46 "Kernel DTrace hooks which are required to load DTrace kernel modules"); 47 48static MALLOC_DEFINE(M_KDTRACE, "kdtrace", "DTrace hooks"); 49 50/* Return the DTrace process data size compiled in the kernel hooks. */ 51size_t 52kdtrace_proc_size() 53{ 54 55 return (KDTRACE_PROC_SIZE); 56} 57 58static void 59kdtrace_proc_ctor(void *arg __unused, struct proc *p) 60{ 61 62 p->p_dtrace = malloc(KDTRACE_PROC_SIZE, M_KDTRACE, M_WAITOK|M_ZERO); 63} 64 65static void 66kdtrace_proc_dtor(void *arg __unused, struct proc *p) 67{ 68 69 if (p->p_dtrace != NULL) { 70 free(p->p_dtrace, M_KDTRACE); 71 p->p_dtrace = NULL; 72 } 73} 74 75/* Return the DTrace thread data size compiled in the kernel hooks. */ 76size_t 77kdtrace_thread_size() 78{ 79 80 return (KDTRACE_THREAD_SIZE); 81} 82 83static void 84kdtrace_thread_ctor(void *arg __unused, struct thread *td) 85{ 86 87 td->td_dtrace = malloc(KDTRACE_THREAD_SIZE, M_KDTRACE, M_WAITOK|M_ZERO); 88} 89 90static void 91kdtrace_thread_dtor(void *arg __unused, struct thread *td) 92{ 93 94 if (td->td_dtrace != NULL) { 95 free(td->td_dtrace, M_KDTRACE); 96 td->td_dtrace = NULL; 97 } 98} 99 100/* 101 * Initialise the kernel DTrace hooks. 102 */ 103static void 104init_dtrace(void *dummy __unused) 105{ 106 107 EVENTHANDLER_REGISTER(process_ctor, kdtrace_proc_ctor, NULL, 108 EVENTHANDLER_PRI_ANY); 109 EVENTHANDLER_REGISTER(process_dtor, kdtrace_proc_dtor, NULL, 110 EVENTHANDLER_PRI_ANY); 111 EVENTHANDLER_REGISTER(thread_ctor, kdtrace_thread_ctor, NULL, 112 EVENTHANDLER_PRI_ANY); 113 EVENTHANDLER_REGISTER(thread_dtor, kdtrace_thread_dtor, NULL, 114 EVENTHANDLER_PRI_ANY); 115} 116 117SYSINIT(kdtrace, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_dtrace, NULL); 118