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authorMark Johnston <markj@FreeBSD.org>2013-08-13 03:10:39 +0000
committerMark Johnston <markj@FreeBSD.org>2013-08-13 03:10:39 +0000
commit8776669b53777489f705930295036a5eb0c5a37e (patch)
tree46930cccd981ff368016d8ab6113a94632ab865f /sys
parent9c6139e411bb55fae4d7449b71bb06059d9ee090 (diff)
downloadsrc-8776669b53777489f705930295036a5eb0c5a37e.tar.gz
src-8776669b53777489f705930295036a5eb0c5a37e.zip
FreeBSD's DTrace implementation has a few problems with respect to handling
probes declared in a kernel module when that module is unloaded. In particular, * Unloading a module with active SDT probes will cause a panic. [1] * A module's (FBT/SDT) probes aren't destroyed when the module is unloaded; trying to use them after the fact will generally cause a panic. This change fixes both problems by porting the DTrace module load/unload handlers from illumos and registering them with the corresponding EVENTHANDLER(9) handlers. This allows the DTrace framework to destroy all probes defined in a module when that module is unloaded, and to prevent a module unload from proceeding if some of its probes are active. The latter problem has already been fixed for FBT probes by checking lf->nenabled in kern_kldunload(), but moving the check into the DTrace framework generalizes it to all kernel providers and also fixes a race in the current implementation (since a probe may be activated between the check and the call to linker_file_unload()). Additionally, the SDT implementation has been reworked to define SDT providers/probes/argtypes in linker sets rather than using SYSINIT/SYSUNINIT to create and destroy SDT probes when a module is loaded or unloaded. This simplifies things quite a bit since it means that pretty much all of the SDT code can live in sdt.ko, and since it becomes easier to integrate SDT with the DTrace framework. Furthermore, this allows FreeBSD to be quite flexible in that SDT providers spanning multiple modules can be created on the fly when a module is loaded; at the moment it looks like illumos' SDT implementation requires all SDT probes to be statically defined in a single kernel table. PR: 166927, 166926, 166928 Reported by: davide [1] Reviewed by: avg, trociny (earlier version) MFC after: 1 month
Notes
Notes: svn path=/head/; revision=254268
Diffstat (limited to 'sys')
-rw-r--r--sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c79
-rw-r--r--sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h2
-rw-r--r--sys/cddl/dev/dtrace/dtrace_load.c6
-rw-r--r--sys/cddl/dev/dtrace/dtrace_unload.c2
-rw-r--r--sys/cddl/dev/fbt/fbt.c13
-rw-r--r--sys/cddl/dev/sdt/sdt.c285
-rw-r--r--sys/kern/kern_linker.c6
-rw-r--r--sys/kern/kern_sdt.c298
-rw-r--r--sys/sys/sdt.h158
9 files changed, 362 insertions, 487 deletions
diff --git a/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c b/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
index dd4ec77f061d..425b4454880c 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c
@@ -116,6 +116,7 @@
#if !defined(sun)
#include <sys/callout.h>
#include <sys/ctype.h>
+#include <sys/eventhandler.h>
#include <sys/limits.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
@@ -240,6 +241,8 @@ int dtrace_in_probe; /* non-zero if executing a probe */
#if defined(__i386__) || defined(__amd64__) || defined(__mips__) || defined(__powerpc__)
uintptr_t dtrace_in_probe_addr; /* Address of invop when already in probe */
#endif
+static eventhandler_tag dtrace_modload_tag;
+static eventhandler_tag dtrace_modunload_tag;
#endif
/*
@@ -8098,19 +8101,6 @@ dtrace_probe_description(const dtrace_probe_t *prp, dtrace_probedesc_t *pdp)
(void) strncpy(pdp->dtpd_name, prp->dtpr_name, DTRACE_NAMELEN - 1);
}
-#if !defined(sun)
-static int
-dtrace_probe_provide_cb(linker_file_t lf, void *arg)
-{
- dtrace_provider_t *prv = (dtrace_provider_t *) arg;
-
- prv->dtpv_pops.dtps_provide_module(prv->dtpv_arg, lf);
-
- return(0);
-}
-#endif
-
-
/*
* Called to indicate that a probe -- or probes -- should be provided by a
* specfied provider. If the specified description is NULL, the provider will
@@ -8166,8 +8156,6 @@ dtrace_probe_provide(dtrace_probedesc_t *desc, dtrace_provider_t *prv)
} while ((ctl = ctl->mod_next) != &modules);
mutex_exit(&mod_lock);
-#else
- (void) linker_file_foreach(dtrace_probe_provide_cb, prv);
#endif
} while (all && (prv = prv->dtpv_next) != NULL);
}
@@ -15152,7 +15140,6 @@ dtrace_helpers_duplicate(proc_t *from, proc_t *to)
dtrace_helper_provider_register(to, newhelp, NULL);
}
-#if defined(sun)
/*
* DTrace Hook Functions
*/
@@ -15166,7 +15153,9 @@ dtrace_module_loaded(modctl_t *ctl)
mutex_enter(&mod_lock);
#endif
+#if defined(sun)
ASSERT(ctl->mod_busy);
+#endif
/*
* We're going to call each providers per-module provide operation
@@ -15214,12 +15203,29 @@ dtrace_module_loaded(modctl_t *ctl)
}
static void
+#if defined(sun)
dtrace_module_unloaded(modctl_t *ctl)
+#else
+dtrace_module_unloaded(modctl_t *ctl, int *error)
+#endif
{
dtrace_probe_t template, *probe, *first, *next;
dtrace_provider_t *prov;
+#if !defined(sun)
+ char modname[DTRACE_MODNAMELEN];
+ size_t len;
+#endif
+#if defined(sun)
template.dtpr_mod = ctl->mod_modname;
+#else
+ /* Handle the fact that ctl->filename may end in ".ko". */
+ strlcpy(modname, ctl->filename, sizeof(modname));
+ len = strlen(ctl->filename);
+ if (len > 3 && strcmp(modname + len - 3, ".ko") == 0)
+ modname[len - 3] = '\0';
+ template.dtpr_mod = modname;
+#endif
mutex_enter(&dtrace_provider_lock);
#if defined(sun)
@@ -15227,6 +15233,18 @@ dtrace_module_unloaded(modctl_t *ctl)
#endif
mutex_enter(&dtrace_lock);
+#if !defined(sun)
+ if (ctl->nenabled > 0) {
+ /* Don't allow unloads if a probe is enabled. */
+ mutex_exit(&dtrace_provider_lock);
+ mutex_exit(&dtrace_lock);
+ *error = -1;
+ printf(
+ "kldunload: attempt to unload module that has DTrace probes enabled\n");
+ return;
+ }
+#endif
+
if (dtrace_bymod == NULL) {
/*
* The DTrace module is loaded (obviously) but not attached;
@@ -15260,8 +15278,13 @@ dtrace_module_unloaded(modctl_t *ctl)
* probe, either.
*/
if (dtrace_err_verbose) {
+#if defined(sun)
cmn_err(CE_WARN, "unloaded module '%s' had "
"enabled probes", ctl->mod_modname);
+#else
+ cmn_err(CE_WARN, "unloaded module '%s' had "
+ "enabled probes", modname);
+#endif
}
return;
@@ -15304,7 +15327,11 @@ dtrace_module_unloaded(modctl_t *ctl)
kmem_free(probe->dtpr_mod, strlen(probe->dtpr_mod) + 1);
kmem_free(probe->dtpr_func, strlen(probe->dtpr_func) + 1);
kmem_free(probe->dtpr_name, strlen(probe->dtpr_name) + 1);
+#if defined(sun)
vmem_free(dtrace_arena, (void *)(uintptr_t)probe->dtpr_id, 1);
+#else
+ free_unr(dtrace_arena, probe->dtpr_id);
+#endif
kmem_free(probe, sizeof (dtrace_probe_t));
}
@@ -15315,6 +15342,26 @@ dtrace_module_unloaded(modctl_t *ctl)
mutex_exit(&dtrace_provider_lock);
}
+#if !defined(sun)
+static void
+dtrace_mod_load(void *arg __unused, linker_file_t lf)
+{
+
+ dtrace_module_loaded(lf);
+}
+
+static void
+dtrace_mod_unload(void *arg __unused, linker_file_t lf, int *error)
+{
+
+ if (*error != 0)
+ /* We already have an error, so don't do anything. */
+ return;
+ dtrace_module_unloaded(lf, error);
+}
+#endif
+
+#if defined(sun)
static void
dtrace_suspend(void)
{
diff --git a/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h b/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h
index 4595c2ee484a..8728e300df94 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/sys/dtrace.h
@@ -2312,8 +2312,10 @@ extern void dtrace_membar_producer(void);
extern void dtrace_membar_consumer(void);
extern void (*dtrace_cpu_init)(processorid_t);
+#if defined(sun)
extern void (*dtrace_modload)(modctl_t *);
extern void (*dtrace_modunload)(modctl_t *);
+#endif
extern void (*dtrace_helpers_cleanup)(void);
extern void (*dtrace_helpers_fork)(proc_t *parent, proc_t *child);
extern void (*dtrace_cpustart_init)(void);
diff --git a/sys/cddl/dev/dtrace/dtrace_load.c b/sys/cddl/dev/dtrace/dtrace_load.c
index 9c5681a6e822..a153e7eefca8 100644
--- a/sys/cddl/dev/dtrace/dtrace_load.c
+++ b/sys/cddl/dev/dtrace/dtrace_load.c
@@ -56,6 +56,12 @@ dtrace_load(void *dummy)
/* Hang our hook for exceptions. */
dtrace_invop_init();
+ /* Register callbacks for module load and unload events. */
+ dtrace_modload_tag = EVENTHANDLER_REGISTER(mod_load,
+ dtrace_mod_load, NULL, EVENTHANDLER_PRI_ANY);
+ dtrace_modunload_tag = EVENTHANDLER_REGISTER(mod_unload,
+ dtrace_mod_unload, NULL, EVENTHANDLER_PRI_ANY);
+
/*
* Initialise the mutexes without 'witness' because the dtrace
* code is mostly written to wait for memory. To have the
diff --git a/sys/cddl/dev/dtrace/dtrace_unload.c b/sys/cddl/dev/dtrace/dtrace_unload.c
index 33d7c403f97a..f8d2ec690ec3 100644
--- a/sys/cddl/dev/dtrace/dtrace_unload.c
+++ b/sys/cddl/dev/dtrace/dtrace_unload.c
@@ -67,6 +67,8 @@ dtrace_unload()
}
dtrace_provider = NULL;
+ EVENTHANDLER_DEREGISTER(mod_load, dtrace_modload_tag);
+ EVENTHANDLER_DEREGISTER(mod_unload, dtrace_modunload_tag);
if ((state = dtrace_anon_grab()) != NULL) {
/*
diff --git a/sys/cddl/dev/fbt/fbt.c b/sys/cddl/dev/fbt/fbt.c
index b8281631f0d4..7b278f729909 100644
--- a/sys/cddl/dev/fbt/fbt.c
+++ b/sys/cddl/dev/fbt/fbt.c
@@ -1335,6 +1335,15 @@ fbt_getargdesc(void *arg __unused, dtrace_id_t id __unused, void *parg, dtrace_a
return;
}
+static int
+fbt_linker_file_cb(linker_file_t lf, void *arg)
+{
+
+ fbt_provide_module(arg, lf);
+
+ return (0);
+}
+
static void
fbt_load(void *dummy)
{
@@ -1359,8 +1368,10 @@ fbt_load(void *dummy)
if (dtrace_register("fbt", &fbt_attr, DTRACE_PRIV_USER,
NULL, &fbt_pops, NULL, &fbt_id) != 0)
return;
-}
+ /* Create probes for the kernel and already-loaded modules. */
+ linker_file_foreach(fbt_linker_file_cb, NULL);
+}
static int
fbt_unload()
diff --git a/sys/cddl/dev/sdt/sdt.c b/sys/cddl/dev/sdt/sdt.c
index 96ab550843f6..493ab9b0bcf2 100644
--- a/sys/cddl/dev/sdt/sdt.c
+++ b/sys/cddl/dev/sdt/sdt.c
@@ -24,36 +24,44 @@
*
*/
-#ifndef KDTRACE_HOOKS
-#define KDTRACE_HOOKS
-#endif
+#include "opt_kdtrace.h"
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/systm.h>
+
#include <sys/conf.h>
+#include <sys/eventhandler.h>
#include <sys/kernel.h>
#include <sys/limits.h>
-#include <sys/lock.h>
#include <sys/linker.h>
+#include <sys/linker_set.h>
+#include <sys/lock.h>
+#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
-
-#include <sys/dtrace.h>
+#include <sys/queue.h>
#include <sys/sdt.h>
-#define SDT_ADDR2NDX(addr) (((uintptr_t)(addr)) >> 4)
+#include <sys/dtrace.h>
+#include <sys/dtrace_bsd.h>
-static d_open_t sdt_open;
-static int sdt_unload(void);
+/* 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 d_open_t sdt_open;
static void sdt_load(void *);
-static int sdt_provider_unreg_callback(struct sdt_provider *prov,
- void *arg);
+static int sdt_unload(void *);
+static void sdt_create_provider(struct sdt_provider *);
+static void sdt_create_probe(struct sdt_probe *);
+static void sdt_modload(void *, struct linker_file *);
+static void sdt_modunload(void *, struct linker_file *, int *);
+
+static MALLOC_DEFINE(M_SDT, "SDT", "DTrace SDT providers");
static struct cdevsw sdt_cdevsw = {
.d_version = D_VERSION,
@@ -79,141 +87,261 @@ static dtrace_pops_t sdt_pops = {
sdt_getargdesc,
NULL,
NULL,
- sdt_destroy
+ sdt_destroy,
};
-static struct cdev *sdt_cdev;
+static struct cdev *sdt_cdev;
-static int
-sdt_argtype_callback(struct sdt_argtype *argtype, void *arg)
-{
- dtrace_argdesc_t *desc = arg;
+static TAILQ_HEAD(, sdt_provider) sdt_prov_list;
- if (desc->dtargd_ndx == argtype->ndx) {
- desc->dtargd_mapping = desc->dtargd_ndx; /* XXX */
- strlcpy(desc->dtargd_native, argtype->type,
- sizeof(desc->dtargd_native));
- desc->dtargd_xlate[0] = '\0'; /* XXX */
- }
-
- return (0);
-}
+eventhandler_tag modload_tag;
+eventhandler_tag modunload_tag;
static void
-sdt_getargdesc(void *arg, dtrace_id_t id, void *parg, dtrace_argdesc_t *desc)
+sdt_create_provider(struct sdt_provider *prov)
{
- struct sdt_probe *probe = parg;
+ struct sdt_provider *curr, *newprov;
- if (desc->dtargd_ndx < probe->n_args)
- (void) (sdt_argtype_listall(probe, sdt_argtype_callback, desc));
- else
- desc->dtargd_ndx = DTRACE_ARGNONE;
+ 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_INIT(&newprov->probe_list);
+
+ TAILQ_INSERT_TAIL(&sdt_prov_list, newprov, prov_entry);
- return;
+ (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 int
-sdt_probe_callback(struct sdt_probe *probe, void *arg __unused)
+static void
+sdt_create_probe(struct sdt_probe *probe)
{
- struct sdt_provider *prov = probe->prov;
- char mod[64];
- char func[64];
- char name[64];
+ struct sdt_provider *prov;
+ char mod[DTRACE_MODNAMELEN];
+ char func[DTRACE_FUNCNAMELEN];
+ char name[DTRACE_NAMELEN];
+ size_t len;
+
+ 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 gcc, so we have to respect const vs non-const.
+ * in the C compiler, so we have to respect const vs non-const.
*/
- strlcpy(mod, probe->mod, sizeof(mod));
strlcpy(func, probe->func, sizeof(func));
strlcpy(name, probe->name, sizeof(name));
- if (dtrace_probe_lookup(prov->id, mod, func, name) != 0)
- return (0);
+ if (dtrace_probe_lookup(prov->id, mod, func, name) != DTRACE_IDNONE)
+ return;
- (void) dtrace_probe_create(prov->id, probe->mod, probe->func,
- probe->name, 1, probe);
+ TAILQ_INSERT_TAIL(&prov->probe_list, probe, probe_entry);
- return (0);
+ (void)dtrace_probe_create(prov->id, mod, func, name, 1, probe);
}
-static int
-sdt_provider_entry(struct sdt_provider *prov, void *arg)
+/* Probes are created through the SDT module load/unload hook. */
+static void
+sdt_provide_probes(void *arg, dtrace_probedesc_t *desc)
{
- return (sdt_probe_listall(prov, sdt_probe_callback, NULL));
}
static void
-sdt_provide_probes(void *arg, dtrace_probedesc_t *desc)
+sdt_enable(void *arg __unused, dtrace_id_t id, void *parg)
{
- if (desc != NULL)
- return;
+ struct sdt_probe *probe = parg;
- (void) sdt_provider_listall(sdt_provider_entry, NULL);
+ probe->id = id;
+ probe->sdtp_lf->nenabled++;
}
static void
-sdt_destroy(void *arg, dtrace_id_t id, void *parg)
+sdt_disable(void *arg __unused, dtrace_id_t id, void *parg)
{
- /* Nothing to do here. */
+ struct sdt_probe *probe = parg;
+
+ KASSERT(probe->sdtp_lf->nenabled > 0, ("no probes enabled"));
+
+ probe->id = 0;
+ probe->sdtp_lf->nenabled--;
}
static void
-sdt_enable(void *arg, dtrace_id_t id, void *parg)
+sdt_getargdesc(void *arg, dtrace_id_t id, void *parg, dtrace_argdesc_t *desc)
{
+ struct sdt_argtype *argtype;
struct sdt_probe *probe = parg;
- probe->id = id;
+ if (desc->dtargd_ndx < probe->n_args) {
+ TAILQ_FOREACH(argtype, &probe->argtype_list, argtype_entry) {
+ if (desc->dtargd_ndx == argtype->ndx) {
+ /* XXX */
+ desc->dtargd_mapping = desc->dtargd_ndx;
+ strlcpy(desc->dtargd_native, argtype->type,
+ sizeof(desc->dtargd_native));
+ desc->dtargd_xlate[0] = '\0'; /* XXX */
+ }
+ }
+ } else
+ desc->dtargd_ndx = DTRACE_ARGNONE;
}
static void
-sdt_disable(void *arg, dtrace_id_t id, void *parg)
+sdt_destroy(void *arg, dtrace_id_t id, void *parg)
{
- struct sdt_probe *probe = parg;
+ struct sdt_probe *probe;
- probe->id = 0;
+ probe = parg;
+ TAILQ_REMOVE(&probe->prov->probe_list, probe, probe_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. We cannot do this in the
+ * provide_module method since it's called with the provider lock held
+ * and dtrace_register() will try to acquire it again.
+ */
+static void
+sdt_modload(void *arg __unused, 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))
+ return;
+ for (prov = begin; prov < end; prov++)
+ sdt_create_provider(*prov);
+
+ if (linker_file_lookup_set(lf, "sdt_probes_set", &p_begin, &p_end,
+ NULL))
+ return;
+ 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))
+ return;
+ for (argtype = a_begin; argtype < a_end; argtype++) {
+ (*argtype)->probe->n_args++;
+ TAILQ_INSERT_TAIL(&(*argtype)->probe->argtype_list, *argtype,
+ argtype_entry);
+ }
+}
+
+static void
+sdt_modunload(void *arg __unused, struct linker_file *lf, int *error __unused)
+{
+ 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 module. */
+ return;
+
+ /*
+ * Go through all the providers declared in this module and unregister
+ * any that aren't declared in another loaded module.
+ */
+ for (curr = begin; curr < end; curr++) {
+ TAILQ_FOREACH_SAFE(prov, &sdt_prov_list, prov_entry, tmp) {
+ if (strcmp(prov->name, (*curr)->name) == 0) {
+ if (prov->sdt_refs == 1) {
+ TAILQ_REMOVE(&sdt_prov_list, prov,
+ prov_entry);
+ dtrace_unregister(prov->id);
+ free(prov->name, M_SDT);
+ free(prov, M_SDT);
+ } else
+ prov->sdt_refs--;
+ break;
+ }
+ }
+ }
}
static int
-sdt_provider_reg_callback(struct sdt_provider *prov, void *arg __unused)
+sdt_linker_file_cb(linker_file_t lf, void *arg __unused)
{
- return (dtrace_register(prov->name, &sdt_attr, DTRACE_PRIV_USER,
- NULL, &sdt_pops, NULL, (dtrace_provider_id_t *) &prov->id));
+
+ sdt_modload(NULL, lf);
+
+ return (0);
}
static void
-sdt_load(void *dummy)
+sdt_load(void *arg __unused)
{
+
+ TAILQ_INIT(&sdt_prov_list);
+
/* Create the /dev/dtrace/sdt entry. */
sdt_cdev = make_dev(&sdt_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
"dtrace/sdt");
sdt_probe_func = dtrace_probe;
- sdt_register_callbacks(sdt_provider_reg_callback, NULL,
- sdt_provider_unreg_callback, NULL, sdt_probe_callback, NULL);
-}
+ modload_tag = EVENTHANDLER_REGISTER(mod_load, sdt_modload, NULL,
+ EVENTHANDLER_PRI_ANY);
+ modunload_tag = EVENTHANDLER_REGISTER(mod_unload, sdt_modunload, NULL,
+ EVENTHANDLER_PRI_ANY);
-static int
-sdt_provider_unreg_callback(struct sdt_provider *prov, void *arg __unused)
-{
- return (dtrace_unregister(prov->id));
+ /* Pick up probes from the kernel and already-loaded modules. */
+ linker_file_foreach(sdt_linker_file_cb, NULL);
}
static int
-sdt_unload()
+sdt_unload(void *arg __unused)
{
- int error = 0;
+ struct sdt_provider *prov, *tmp;
+
+ EVENTHANDLER_DEREGISTER(mod_load, modload_tag);
+ EVENTHANDLER_DEREGISTER(mod_unload, modunload_tag);
sdt_probe_func = sdt_probe_stub;
- sdt_deregister_callbacks();
-
+ TAILQ_FOREACH_SAFE(prov, &sdt_prov_list, prov_entry, tmp) {
+ TAILQ_REMOVE(&sdt_prov_list, prov, prov_entry);
+ dtrace_unregister(prov->id);
+ free(prov->name, M_SDT);
+ free(prov, M_SDT);
+ }
+
destroy_dev(sdt_cdev);
- return (error);
+ return (0);
}
/* ARGSUSED */
@@ -235,7 +363,6 @@ sdt_modevent(module_t mod __unused, int type, void *data __unused)
default:
error = EOPNOTSUPP;
break;
-
}
return (error);
@@ -243,8 +370,10 @@ sdt_modevent(module_t mod __unused, int type, void *data __unused)
/* ARGSUSED */
static int
-sdt_open(struct cdev *dev __unused, int oflags __unused, int devtype __unused, struct thread *td __unused)
+sdt_open(struct cdev *dev __unused, int oflags __unused, int devtype __unused,
+ struct thread *td __unused)
{
+
return (0);
}
diff --git a/sys/kern/kern_linker.c b/sys/kern/kern_linker.c
index 9a4c4db9cb4b..252bd2e2a239 100644
--- a/sys/kern/kern_linker.c
+++ b/sys/kern/kern_linker.c
@@ -1106,11 +1106,7 @@ kern_kldunload(struct thread *td, int fileid, int flags)
EVENTHANDLER_INVOKE(mod_unload, lf, &error);
if (error != 0)
error = EBUSY;
- else if (lf->nenabled > 0) {
- printf("kldunload: attempt to unload file that has"
- " DTrace probes enabled\n");
- error = EBUSY;
- } else if (lf->userrefs == 0) {
+ else if (lf->userrefs == 0) {
/*
* XXX: maybe LINKER_UNLOAD_FORCE should override ?
*/
diff --git a/sys/kern/kern_sdt.c b/sys/kern/kern_sdt.c
index ee4addee0c12..c8e1940fbd71 100644
--- a/sys/kern/kern_sdt.c
+++ b/sys/kern/kern_sdt.c
@@ -23,317 +23,29 @@
* 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.
+ * 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;
-static sdt_provider_listall_func_t sdt_provider_register_func = NULL;
-static sdt_provider_listall_func_t sdt_provider_deregister_func = NULL;
-static sdt_probe_listall_func_t sdt_probe_register_func = NULL;
-
-static void *sdt_provider_register_arg;
-static void *sdt_provider_deregister_arg;
-static void *sdt_probe_register_arg;
-
-static int sdt_provider_listall_locked(sdt_provider_listall_func_t, void *);
-
/*
* 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.
+ * enabled. It should never get called because there is no DTrace support
+ * to enable it.
*/
void
sdt_probe_stub(uint32_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);
-
- if (sdt_provider_register_func != NULL)
- sdt_provider_register_func(prov, sdt_provider_register_arg);
-
- 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);
-
- if (sdt_provider_deregister_func != NULL)
- sdt_provider_deregister_func(prov, sdt_provider_deregister_arg);
-
- 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;
-
- if (sdt_probe_register_func != NULL)
- sdt_probe_register_func(probe, sdt_provider_register_arg);
-
- 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;
-
- sx_xlock(&sdt_sx);
- error = sdt_provider_listall_locked(callback_func, arg);
- sx_xunlock(&sdt_sx);
-
- return (error);
-}
-
-static int
-sdt_provider_listall_locked(sdt_provider_listall_func_t callback_func,
- void *arg)
-{
- int error = 0;
- struct sdt_provider *prov;
-
- sx_assert(&sdt_sx, SX_XLOCKED);
-
- TAILQ_FOREACH(prov, &sdt_provider_list, prov_entry) {
- if ((error = callback_func(prov, arg)) != 0)
- break;
- }
-
- 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);
-}
-
-void sdt_register_callbacks(sdt_provider_listall_func_t register_prov,
- void *reg_prov_arg, sdt_provider_listall_func_t deregister_prov,
- void *dereg_prov_arg, sdt_probe_listall_func_t register_probe,
- void * reg_probe_arg)
-{
-
- sx_xlock(&sdt_sx);
- sdt_provider_register_func = register_prov;
- sdt_provider_deregister_func = deregister_prov;
- sdt_probe_register_func = register_probe;
-
- sdt_provider_register_arg = reg_prov_arg;
- sdt_provider_deregister_arg = dereg_prov_arg;
- sdt_probe_register_arg = reg_probe_arg;
-
- sdt_provider_listall_locked(register_prov, reg_prov_arg);
- sx_xunlock(&sdt_sx);
-}
-
-void sdt_deregister_callbacks(void)
-{
-
- sx_xlock(&sdt_sx);
- sdt_provider_listall_locked(sdt_provider_deregister_func,
- sdt_provider_deregister_arg);
-
- sdt_provider_register_func = NULL;
- sdt_provider_deregister_func = NULL;
- sdt_probe_register_func = NULL;
-
- sdt_provider_register_arg = NULL;
- sdt_provider_deregister_arg = NULL;
- sdt_probe_register_arg = NULL;
- sx_xunlock(&sdt_sx);
+ printf("sdt_probe_stub: Why did this get called?\n");
}
diff --git a/sys/sys/sdt.h b/sys/sys/sdt.h
index 9c3684151fde..02b4eba22c98 100644
--- a/sys/sys/sdt.h
+++ b/sys/sys/sdt.h
@@ -77,6 +77,9 @@
#else /* _KERNEL */
+#include <sys/cdefs.h>
+#include <sys/linker_set.h>
+
#ifndef KDTRACE_HOOKS
#define SDT_PROVIDER_DEFINE(prov)
@@ -109,85 +112,26 @@
#else
-/*
- * This type definition must match that of dtrace_probe. It is defined this
- * way to avoid having to rely on CDDL code.
- */
-typedef void (*sdt_probe_func_t)(u_int32_t, uintptr_t arg0, uintptr_t arg1,
- uintptr_t arg2, uintptr_t arg3, uintptr_t arg4);
-
-/*
- * The hook for the probe function. See kern_sdt.c which defaults this to
- * it's own stub. The 'sdt' provider will set it to dtrace_probe when it
- * loads.
- */
-extern sdt_probe_func_t sdt_probe_func;
-
-typedef enum {
- SDT_UNINIT = 1,
- SDT_INIT,
-} sdt_state_t;
-
-struct sdt_probe;
-struct sdt_provider;
-
-struct sdt_argtype {
- int ndx; /* Argument index. */
- const char *type; /* Argument type string. */
- TAILQ_ENTRY(sdt_argtype)
- argtype_entry; /* Argument type list entry. */
- struct sdt_probe
- *probe; /* Ptr to the probe structure. */
-};
-
-struct sdt_probe {
- int version; /* Set to sizeof(struct sdt_ref). */
- sdt_state_t state;
- struct sdt_provider
- *prov; /* Ptr to the provider structure. */
- TAILQ_ENTRY(sdt_probe)
- probe_entry; /* SDT probe list entry. */
- TAILQ_HEAD(argtype_list_head, sdt_argtype) argtype_list;
- const char *mod;
- const char *func;
- const char *name;
- id_t id; /* DTrace probe ID. */
- int n_args; /* Number of arguments. */
-};
-
-struct sdt_provider {
- const char *name; /* Provider name. */
- TAILQ_ENTRY(sdt_provider)
- prov_entry; /* SDT provider list entry. */
- TAILQ_HEAD(probe_list_head, sdt_probe) probe_list;
- uintptr_t id; /* DTrace provider ID. */
-};
+SET_DECLARE(sdt_providers_set, struct sdt_provider);
+SET_DECLARE(sdt_probes_set, struct sdt_probe);
+SET_DECLARE(sdt_argtypes_set, struct sdt_argtype);
#define SDT_PROVIDER_DEFINE(prov) \
struct sdt_provider sdt_provider_##prov[1] = { \
- { #prov, { NULL, NULL }, { NULL, NULL } } \
+ { #prov, { NULL, NULL }, { NULL, NULL }, 0, 0 } \
}; \
- SYSINIT(sdt_provider_##prov##_init, SI_SUB_KDTRACE, \
- SI_ORDER_SECOND, sdt_provider_register, \
- sdt_provider_##prov ); \
- SYSUNINIT(sdt_provider_##prov##_uninit, SI_SUB_KDTRACE, \
- SI_ORDER_SECOND, sdt_provider_deregister, \
- sdt_provider_##prov )
+ DATA_SET(sdt_providers_set, sdt_provider_##prov);
#define SDT_PROVIDER_DECLARE(prov) \
extern struct sdt_provider sdt_provider_##prov[1]
#define SDT_PROBE_DEFINE(prov, mod, func, name, sname) \
struct sdt_probe sdt_##prov##_##mod##_##func##_##name[1] = { \
- { sizeof(struct sdt_probe), 0, sdt_provider_##prov, \
- { NULL, NULL }, { NULL, NULL }, #mod, #func, #sname, 0, 0 } \
+ { sizeof(struct sdt_probe), sdt_provider_##prov, \
+ { NULL, NULL }, { NULL, NULL }, #mod, #func, #sname, 0, 0, \
+ NULL } \
}; \
- SYSINIT(sdt_##prov##_##mod##_##func##_##name##_init, SI_SUB_KDTRACE, \
- SI_ORDER_SECOND + 1, sdt_probe_register, \
- sdt_##prov##_##mod##_##func##_##name ); \
- SYSUNINIT(sdt_##prov##_##mod##_##func##_##name##_uninit, \
- SI_SUB_KDTRACE, SI_ORDER_SECOND + 1, sdt_probe_deregister, \
- sdt_##prov##_##mod##_##func##_##name )
+ DATA_SET(sdt_probes_set, sdt_##prov##_##mod##_##func##_##name);
#define SDT_PROBE_DECLARE(prov, mod, func, name) \
extern struct sdt_probe sdt_##prov##_##mod##_##func##_##name[1]
@@ -204,12 +148,7 @@ struct sdt_provider {
= { { num, type, { NULL, NULL }, \
sdt_##prov##_##mod##_##func##_##name } \
}; \
- SYSINIT(sdt_##prov##_##mod##_##func##_##name##num##_init, \
- SI_SUB_KDTRACE, SI_ORDER_SECOND + 2, sdt_argtype_register, \
- sdt_##prov##_##mod##_##func##_##name##num ); \
- SYSUNINIT(sdt_##prov##_##mod##_##func##_##name##num##_uninit, \
- SI_SUB_KDTRACE, SI_ORDER_SECOND + 2, sdt_argtype_deregister, \
- sdt_##prov##_##mod##_##func##_##name##num )
+ DATA_SET(sdt_argtypes_set, sdt_##prov##_##mod##_##func##_##name##num);
#define SDT_PROBE_DEFINE0(prov, mod, func, name, sname) \
SDT_PROBE_DEFINE(prov, mod, func, name, sname)
@@ -299,28 +238,59 @@ struct sdt_provider {
(uintptr_t)arg6); \
} while (0)
-typedef int (*sdt_argtype_listall_func_t)(struct sdt_argtype *, void *);
-typedef int (*sdt_probe_listall_func_t)(struct sdt_probe *, void *);
-typedef int (*sdt_provider_listall_func_t)(struct sdt_provider *, void *);
-
-void sdt_argtype_deregister(void *);
-void sdt_argtype_register(void *);
-void sdt_probe_deregister(void *);
-void sdt_probe_register(void *);
-void sdt_provider_deregister(void *);
-void sdt_provider_register(void *);
-void sdt_probe_stub(u_int32_t, uintptr_t arg0, uintptr_t arg1, uintptr_t arg2,
- uintptr_t arg3, uintptr_t arg4);
-int sdt_argtype_listall(struct sdt_probe *, sdt_argtype_listall_func_t, void *);
-int sdt_probe_listall(struct sdt_provider *, sdt_probe_listall_func_t, void *);
-int sdt_provider_listall(sdt_provider_listall_func_t,void *);
-
-void sdt_register_callbacks(sdt_provider_listall_func_t, void *,
- sdt_provider_listall_func_t, void *, sdt_probe_listall_func_t, void *);
-void sdt_deregister_callbacks(void);
-
#endif /* KDTRACE_HOOKS */
+/*
+ * This type definition must match that of dtrace_probe. It is defined this
+ * way to avoid having to rely on CDDL code.
+ */
+typedef void (*sdt_probe_func_t)(uint32_t, uintptr_t arg0, uintptr_t arg1,
+ uintptr_t arg2, uintptr_t arg3, uintptr_t arg4);
+
+/*
+ * The 'sdt' provider will set it to dtrace_probe when it loads.
+ */
+extern sdt_probe_func_t sdt_probe_func;
+
+struct sdt_probe;
+struct sdt_provider;
+struct linker_file;
+
+struct sdt_argtype {
+ int ndx; /* Argument index. */
+ const char *type; /* Argument type string. */
+ TAILQ_ENTRY(sdt_argtype)
+ argtype_entry; /* Argument type list entry. */
+ struct sdt_probe
+ *probe; /* Ptr to the probe structure. */
+};
+
+struct sdt_probe {
+ int version; /* Set to sizeof(struct sdt_probe). */
+ struct sdt_provider *prov; /* Ptr to the provider structure. */
+ TAILQ_ENTRY(sdt_probe)
+ probe_entry; /* SDT probe list entry. */
+ TAILQ_HEAD(argtype_list_head, sdt_argtype) argtype_list;
+ const char *mod;
+ const char *func;
+ const char *name;
+ id_t id; /* DTrace probe ID. */
+ int n_args; /* Number of arguments. */
+ struct linker_file *sdtp_lf; /* Module in which we're defined. */
+};
+
+struct sdt_provider {
+ char *name; /* Provider name. */
+ TAILQ_ENTRY(sdt_provider)
+ prov_entry; /* SDT provider list entry. */
+ TAILQ_HEAD(probe_list_head, sdt_probe) probe_list;
+ uintptr_t id; /* DTrace provider ID. */
+ int sdt_refs; /* Number of module references. */
+};
+
+void sdt_probe_stub(uint32_t, uintptr_t, uintptr_t, uintptr_t, uintptr_t,
+ uintptr_t);
+
#endif /* _KERNEL */
#endif /* _SYS_SDT_H */