Index: head/sys/cddl/dev/sdt/sdt.c
===================================================================
--- head/sys/cddl/dev/sdt/sdt.c (revision 368305)
+++ head/sys/cddl/dev/sdt/sdt.c (revision 368306)
@@ -1,419 +1,441 @@
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*
* Portions Copyright 2006-2008 John Birrell jb@freebsd.org
*
* $FreeBSD$
*
*/
/*
* This file contains a reimplementation of the statically-defined tracing (SDT)
* framework for DTrace. Probes and SDT providers are defined using the macros
* in sys/sdt.h, which append all the needed structures to linker sets. When
* this module is loaded, it iterates over all of the loaded modules and
* registers probes and providers with the DTrace framework based on the
* contents of these linker sets.
*
* A list of SDT providers is maintained here since a provider may span multiple
* modules. When a kernel module is unloaded, a provider defined in that module
* is unregistered only if no other modules refer to it. The DTrace framework is
* responsible for destroying individual probes when a kernel module is
* unloaded; in particular, probes may not span multiple kernel modules.
*/
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/endian.h>
#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/linker.h>
#include <sys/linker_set.h>
#include <sys/lock.h>
#include <sys/lockstat.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/queue.h>
#include <sys/sdt.h>
#include <sys/dtrace.h>
#include <sys/dtrace_bsd.h>
/* DTrace methods. */
static void sdt_getargdesc(void *, dtrace_id_t, void *, dtrace_argdesc_t *);
static void sdt_provide_probes(void *, dtrace_probedesc_t *);
static void sdt_destroy(void *, dtrace_id_t, void *);
static void sdt_enable(void *, dtrace_id_t, void *);
static void sdt_disable(void *, dtrace_id_t, void *);
static void sdt_load(void);
static int sdt_unload(void);
static void sdt_create_provider(struct sdt_provider *);
static void sdt_create_probe(struct sdt_probe *);
static void sdt_kld_load(void *, struct linker_file *);
static void sdt_kld_unload_try(void *, struct linker_file *, int *);
static MALLOC_DEFINE(M_SDT, "SDT", "DTrace SDT providers");
static int sdt_probes_enabled_count;
static int lockstat_enabled_count;
static dtrace_pattr_t sdt_attr = {
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
};
static dtrace_pops_t sdt_pops = {
.dtps_provide = sdt_provide_probes,
.dtps_provide_module = NULL,
.dtps_enable = sdt_enable,
.dtps_disable = sdt_disable,
.dtps_suspend = NULL,
.dtps_resume = NULL,
.dtps_getargdesc = sdt_getargdesc,
.dtps_getargval = NULL,
.dtps_usermode = NULL,
.dtps_destroy = sdt_destroy,
};
static TAILQ_HEAD(, sdt_provider) sdt_prov_list;
static eventhandler_tag sdt_kld_load_tag;
static eventhandler_tag sdt_kld_unload_try_tag;
static void
sdt_create_provider(struct sdt_provider *prov)
{
struct sdt_provider *curr, *newprov;
TAILQ_FOREACH(curr, &sdt_prov_list, prov_entry)
if (strcmp(prov->name, curr->name) == 0) {
/* The provider has already been defined. */
curr->sdt_refs++;
return;
}
/*
* Make a copy of prov so that we don't lose fields if its module is
* unloaded but the provider isn't destroyed. This could happen with
* a provider that spans multiple modules.
*/
newprov = malloc(sizeof(*newprov), M_SDT, M_WAITOK | M_ZERO);
newprov->name = strdup(prov->name, M_SDT);
prov->sdt_refs = newprov->sdt_refs = 1;
TAILQ_INSERT_TAIL(&sdt_prov_list, newprov, prov_entry);
(void)dtrace_register(newprov->name, &sdt_attr, DTRACE_PRIV_USER, NULL,
&sdt_pops, NULL, (dtrace_provider_id_t *)&newprov->id);
prov->id = newprov->id;
}
static void
sdt_create_probe(struct sdt_probe *probe)
{
struct sdt_provider *prov;
char mod[DTRACE_MODNAMELEN];
char func[DTRACE_FUNCNAMELEN];
char name[DTRACE_NAMELEN];
const char *from;
char *to;
size_t len;
if (probe->version != (int)sizeof(*probe)) {
printf("ignoring probe %p, version %u expected %u\n",
probe, probe->version, (int)sizeof(*probe));
return;
}
TAILQ_FOREACH(prov, &sdt_prov_list, prov_entry)
if (strcmp(prov->name, probe->prov->name) == 0)
break;
KASSERT(prov != NULL, ("probe defined without a provider"));
/* If no module name was specified, use the module filename. */
if (*probe->mod == 0) {
len = strlcpy(mod, probe->sdtp_lf->filename, sizeof(mod));
if (len > 3 && strcmp(mod + len - 3, ".ko") == 0)
mod[len - 3] = '\0';
} else
strlcpy(mod, probe->mod, sizeof(mod));
/*
* Unfortunately this is necessary because the Solaris DTrace
* code mixes consts and non-consts with casts to override
* the incompatibilies. On FreeBSD, we use strict warnings
* in the C compiler, so we have to respect const vs non-const.
*/
strlcpy(func, probe->func, sizeof(func));
if (func[0] == '\0')
strcpy(func, "none");
from = probe->name;
to = name;
for (len = 0; len < (sizeof(name) - 1) && *from != '\0';
len++, from++, to++) {
if (from[0] == '_' && from[1] == '_') {
*to = '-';
from++;
} else
*to = *from;
}
*to = '\0';
if (dtrace_probe_lookup(prov->id, mod, func, name) != DTRACE_IDNONE)
return;
(void)dtrace_probe_create(prov->id, mod, func, name, 1, probe);
}
/*
* Probes are created through the SDT module load/unload hook, so this function
* has nothing to do. It only exists because the DTrace provider framework
* requires one of provide_probes and provide_module to be defined.
*/
static void
sdt_provide_probes(void *arg, dtrace_probedesc_t *desc)
{
}
static void
sdt_enable(void *arg __unused, dtrace_id_t id, void *parg)
{
struct sdt_probe *probe = parg;
probe->id = id;
probe->sdtp_lf->nenabled++;
if (strcmp(probe->prov->name, "lockstat") == 0) {
lockstat_enabled_count++;
if (lockstat_enabled_count == 1)
lockstat_enabled = true;
}
sdt_probes_enabled_count++;
if (sdt_probes_enabled_count == 1)
sdt_probes_enabled = true;
}
static void
sdt_disable(void *arg __unused, dtrace_id_t id, void *parg)
{
struct sdt_probe *probe = parg;
KASSERT(probe->sdtp_lf->nenabled > 0, ("no probes enabled"));
sdt_probes_enabled_count--;
if (sdt_probes_enabled_count == 0)
sdt_probes_enabled = false;
if (strcmp(probe->prov->name, "lockstat") == 0) {
lockstat_enabled_count--;
if (lockstat_enabled_count == 0)
lockstat_enabled = false;
}
probe->id = 0;
probe->sdtp_lf->nenabled--;
}
static void
sdt_getargdesc(void *arg, dtrace_id_t id, void *parg, dtrace_argdesc_t *desc)
{
struct sdt_argtype *argtype;
struct sdt_probe *probe = parg;
if (desc->dtargd_ndx >= probe->n_args) {
desc->dtargd_ndx = DTRACE_ARGNONE;
return;
}
TAILQ_FOREACH(argtype, &probe->argtype_list, argtype_entry) {
if (desc->dtargd_ndx == argtype->ndx) {
desc->dtargd_mapping = desc->dtargd_ndx;
if (argtype->type == NULL) {
desc->dtargd_native[0] = '\0';
desc->dtargd_xlate[0] = '\0';
continue;
}
strlcpy(desc->dtargd_native, argtype->type,
sizeof(desc->dtargd_native));
if (argtype->xtype != NULL)
strlcpy(desc->dtargd_xlate, argtype->xtype,
sizeof(desc->dtargd_xlate));
}
}
}
static void
sdt_destroy(void *arg, dtrace_id_t id, void *parg)
{
}
-/*
- * Called from the kernel linker when a module is loaded, before
- * dtrace_module_loaded() is called. This is done so that it's possible to
- * register new providers when modules are loaded. The DTrace framework
- * explicitly disallows calling into the framework from the provide_module
- * provider method, so we cannot do this there.
- */
static void
-sdt_kld_load(void *arg __unused, struct linker_file *lf)
+sdt_kld_load_providers(struct linker_file *lf)
{
struct sdt_provider **prov, **begin, **end;
- struct sdt_probe **probe, **p_begin, **p_end;
- struct sdt_argtype **argtype, **a_begin, **a_end;
if (linker_file_lookup_set(lf, "sdt_providers_set", &begin, &end,
NULL) == 0) {
for (prov = begin; prov < end; prov++)
sdt_create_provider(*prov);
}
+}
+static void
+sdt_kld_load_probes(struct linker_file *lf)
+{
+ struct sdt_probe **probe, **p_begin, **p_end;
+ struct sdt_argtype **argtype, **a_begin, **a_end;
+
if (linker_file_lookup_set(lf, "sdt_probes_set", &p_begin, &p_end,
NULL) == 0) {
for (probe = p_begin; probe < p_end; probe++) {
(*probe)->sdtp_lf = lf;
sdt_create_probe(*probe);
TAILQ_INIT(&(*probe)->argtype_list);
}
}
if (linker_file_lookup_set(lf, "sdt_argtypes_set", &a_begin, &a_end,
NULL) == 0) {
for (argtype = a_begin; argtype < a_end; argtype++) {
(*argtype)->probe->n_args++;
TAILQ_INSERT_TAIL(&(*argtype)->probe->argtype_list,
*argtype, argtype_entry);
}
}
}
+/*
+ * Called from the kernel linker when a module is loaded, before
+ * dtrace_module_loaded() is called. This is done so that it's possible to
+ * register new providers when modules are loaded. The DTrace framework
+ * explicitly disallows calling into the framework from the provide_module
+ * provider method, so we cannot do this there.
+ */
static void
+sdt_kld_load(void *arg __unused, struct linker_file *lf)
+{
+ sdt_kld_load_providers(lf);
+ sdt_kld_load_probes(lf);
+}
+
+static void
sdt_kld_unload_try(void *arg __unused, struct linker_file *lf, int *error)
{
struct sdt_provider *prov, **curr, **begin, **end, *tmp;
if (*error != 0)
/* We already have an error, so don't do anything. */
return;
else if (linker_file_lookup_set(lf, "sdt_providers_set", &begin, &end,
NULL))
/* No DTrace providers are declared in this file. */
return;
/*
* Go through all the providers declared in this linker file and
* unregister any that aren't declared in another loaded file.
*/
for (curr = begin; curr < end; curr++) {
TAILQ_FOREACH_SAFE(prov, &sdt_prov_list, prov_entry, tmp) {
if (strcmp(prov->name, (*curr)->name) != 0)
continue;
if (prov->sdt_refs == 1) {
if (dtrace_unregister(prov->id) != 0) {
*error = 1;
return;
}
TAILQ_REMOVE(&sdt_prov_list, prov, prov_entry);
free(prov->name, M_SDT);
free(prov, M_SDT);
} else
prov->sdt_refs--;
break;
}
}
}
static int
-sdt_linker_file_cb(linker_file_t lf, void *arg __unused)
+sdt_load_providers_cb(linker_file_t lf, void *arg __unused)
{
+ sdt_kld_load_providers(lf);
+ return (0);
+}
- sdt_kld_load(NULL, lf);
-
+static int
+sdt_load_probes_cb(linker_file_t lf, void *arg __unused)
+{
+ sdt_kld_load_probes(lf);
return (0);
}
static void
-sdt_load()
+sdt_load(void)
{
TAILQ_INIT(&sdt_prov_list);
sdt_probe_func = dtrace_probe;
sdt_kld_load_tag = EVENTHANDLER_REGISTER(kld_load, sdt_kld_load, NULL,
EVENTHANDLER_PRI_ANY);
sdt_kld_unload_try_tag = EVENTHANDLER_REGISTER(kld_unload_try,
sdt_kld_unload_try, NULL, EVENTHANDLER_PRI_ANY);
- /* Pick up probes from the kernel and already-loaded linker files. */
- linker_file_foreach(sdt_linker_file_cb, NULL);
+ /*
+ * Pick up probes from the kernel and already-loaded linker files.
+ * Define providers in a separate pass since a linker file may be using
+ * providers defined in a file that appears later in the list.
+ */
+ linker_file_foreach(sdt_load_providers_cb, NULL);
+ linker_file_foreach(sdt_load_probes_cb, NULL);
}
static int
-sdt_unload()
+sdt_unload(void)
{
struct sdt_provider *prov, *tmp;
int ret;
EVENTHANDLER_DEREGISTER(kld_load, sdt_kld_load_tag);
EVENTHANDLER_DEREGISTER(kld_unload_try, sdt_kld_unload_try_tag);
sdt_probe_func = sdt_probe_stub;
TAILQ_FOREACH_SAFE(prov, &sdt_prov_list, prov_entry, tmp) {
ret = dtrace_unregister(prov->id);
if (ret != 0)
return (ret);
TAILQ_REMOVE(&sdt_prov_list, prov, prov_entry);
free(prov->name, M_SDT);
free(prov, M_SDT);
}
return (0);
}
static int
sdt_modevent(module_t mod __unused, int type, void *data __unused)
{
switch (type) {
case MOD_LOAD:
case MOD_UNLOAD:
case MOD_SHUTDOWN:
return (0);
default:
return (EOPNOTSUPP);
}
}
SYSINIT(sdt_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, sdt_load, NULL);
SYSUNINIT(sdt_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, sdt_unload, NULL);
DEV_MODULE(sdt, sdt_modevent, NULL);
MODULE_VERSION(sdt, 1);
MODULE_DEPEND(sdt, dtrace, 1, 1, 1);