/*-
* Copyright 2006-2008 John Birrell <jb@FreeBSD.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*
* Backend for the Statically Defined Tracing (SDT) kernel support. This is
* required to allow a module to load even though DTrace kernel support may
* not be present. A module may be built with SDT probes in it which are
* registered and deregistered via SYSINIT/SYSUNINIT.
*
*/
#include "opt_kdtrace.h"
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/proc.h>
#include <sys/sx.h>
#include <sys/sdt.h>
/*
* This is the list of statically defined tracing providers.
*/
static TAILQ_HEAD(sdt_provider_list_head, sdt_provider) sdt_provider_list;
/*
* Mutex to serialise access to the SDT provider list.
*/
static struct sx sdt_sx;
/*
* Hook for the DTrace probe function. The 'sdt' provider will set this
* to dtrace_probe when it loads.
*/
sdt_probe_func_t sdt_probe_func = sdt_probe_stub;
/*
* This is a stub for probe calls in case kernel DTrace support isn't
* compiled in. It should never get called because there is no DTrace
* support to enable it.
*/
void
sdt_probe_stub(u_int32_t id, uintptr_t arg0, uintptr_t arg1,
uintptr_t arg2, uintptr_t arg3, uintptr_t arg4)
{
printf("sdt_probe_stub: Why did this get called?\n");
}
/*
* Called from SYSINIT to register a provider.
*/
void
sdt_provider_register(void *arg)
{
struct sdt_provider *prov = arg;
sx_xlock(&sdt_sx);
TAILQ_INSERT_TAIL(&sdt_provider_list, prov, prov_entry);
TAILQ_INIT(&prov->probe_list);
sx_xunlock(&sdt_sx);
}
/*
* Called from SYSUNINIT to de-register a provider.
*/
void
sdt_provider_deregister(void *arg)
{
struct sdt_provider *prov = arg;
sx_xlock(&sdt_sx);
TAILQ_REMOVE(&sdt_provider_list, prov, prov_entry);
sx_xunlock(&sdt_sx);
}
/*
* Called from SYSINIT to register a statically defined trace probe.
*/
void
sdt_probe_register(void *arg)
{
struct sdt_probe *probe = arg;
/*
* Check the reference structure version. Only version 1 is
* supported at the moment.
*/
if (probe->version != sizeof(struct sdt_probe)) {
printf("%s:%s:%s has version %d when %d required\n", probe->mod, probe->func, probe->name, probe->version, (int) sizeof(struct sdt_probe));
return;
}
sx_xlock(&sdt_sx);
TAILQ_INSERT_TAIL(&probe->prov->probe_list, probe, probe_entry);
TAILQ_INIT(&probe->argtype_list);
probe->state = SDT_INIT;
sx_xunlock(&sdt_sx);
}
/*
* Called from SYSUNINIT to de-register a statically defined trace probe.
*/
void
sdt_probe_deregister(void *arg)
{
struct sdt_probe *probe = arg;
sx_xlock(&sdt_sx);
if (probe->state == SDT_INIT) {
TAILQ_REMOVE(&probe->prov->probe_list, probe, probe_entry);
probe->state = SDT_UNINIT;
}
sx_xunlock(&sdt_sx);
}
/*
* Called from SYSINIT to register a statically defined trace probe argument.
*/
void
sdt_argtype_register(void *arg)
{
struct sdt_argtype *argtype = arg;
sx_xlock(&sdt_sx);
TAILQ_INSERT_TAIL(&argtype->probe->argtype_list, argtype, argtype_entry);
argtype->probe->n_args++;
sx_xunlock(&sdt_sx);
}
/*
* Called from SYSUNINIT to de-register a statically defined trace probe argument.
*/
void
sdt_argtype_deregister(void *arg)
{
struct sdt_argtype *argtype = arg;
sx_xlock(&sdt_sx);
TAILQ_REMOVE(&argtype->probe->argtype_list, argtype, argtype_entry);
sx_xunlock(&sdt_sx);
}
static void
sdt_init(void *arg)
{
sx_init_flags(&sdt_sx, "Statically Defined Tracing", SX_NOWITNESS);
TAILQ_INIT(&sdt_provider_list);
}
SYSINIT(sdt, SI_SUB_KDTRACE, SI_ORDER_FIRST, sdt_init, NULL);
static void
sdt_uninit(void *arg)
{
sx_destroy(&sdt_sx);
}
SYSUNINIT(sdt, SI_SUB_KDTRACE, SI_ORDER_FIRST, sdt_uninit, NULL);
/*
* List statically defined tracing providers.
*/
int
sdt_provider_listall(sdt_provider_listall_func_t callback_func,void *arg)
{
int error = 0;
struct sdt_provider *prov;
sx_xlock(&sdt_sx);
TAILQ_FOREACH(prov, &sdt_provider_list, prov_entry) {
if ((error = callback_func(prov, arg)) != 0)
break;
}
sx_xunlock(&sdt_sx);
return (error);
}
/*
* List statically defined tracing probes.
*/
int
sdt_probe_listall(struct sdt_provider *prov,
sdt_probe_listall_func_t callback_func,void *arg)
{
int error = 0;
int locked;
struct sdt_probe *probe;
locked = sx_xlocked(&sdt_sx);
if (!locked)
sx_xlock(&sdt_sx);
TAILQ_FOREACH(probe, &prov->probe_list, probe_entry) {
if ((error = callback_func(probe, arg)) != 0)
break;
}
if (!locked)
sx_xunlock(&sdt_sx);
return (error);
}
/*
* List statically defined tracing probe arguments.
*/
int
sdt_argtype_listall(struct sdt_probe *probe,
sdt_argtype_listall_func_t callback_func,void *arg)
{
int error = 0;
int locked;
struct sdt_argtype *argtype;
locked = sx_xlocked(&sdt_sx);
if (!locked)
sx_xlock(&sdt_sx);
TAILQ_FOREACH(argtype, &probe->argtype_list, argtype_entry) {
if ((error = callback_func(argtype, arg)) != 0)
break;
}
if (!locked)
sx_xunlock(&sdt_sx);
return (error);
}
