sys/kern/kern_dtrace.c

   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
  46 FEATURE(kdtrace_hooks,
  47     "Kernel DTrace hooks which are required to load DTrace kernel modules");
  48
  49 static MALLOC_DEFINE(M_KDTRACE, "kdtrace", "DTrace hooks");
  50
  51 /* Hooks used in the machine-dependent trap handlers. */
  52 dtrace_trap_func_t              dtrace_trap_func;
  53 dtrace_doubletrap_func_t        dtrace_doubletrap_func;
  54 dtrace_pid_probe_ptr_t          dtrace_pid_probe_ptr;
  55 dtrace_return_probe_ptr_t       dtrace_return_probe_ptr;
  56
  57 systrace_probe_func_t           systrace_probe_func;
  58
  59 /* Return the DTrace process data size compiled in the kernel hooks. */
  60 size_t
  61 kdtrace_proc_size()
  62 {
  63
  64         return (KDTRACE_PROC_SIZE);
  65 }
  66
  67 static void
  68 kdtrace_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
  74 static void
  75 kdtrace_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. */
  85 size_t
  86 kdtrace_thread_size()
  87 {
  88
  89         return (KDTRACE_THREAD_SIZE);
  90 }
  91
  92 static void
  93 kdtrace_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
  99 static void
 100 kdtrace_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  */
 112 static void
 113 init_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
 126 SYSINIT(kdtrace, SI_SUB_KDTRACE, SI_ORDER_FIRST, init_dtrace, NULL);