4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
21 * Portions Copyright 2006-2008 John Birrell jb@freebsd.org
28 * This file contains a reimplementation of the statically-defined tracing (SDT)
29 * framework for DTrace. Probes and SDT providers are defined using the macros
30 * in sys/sdt.h, which append all the needed structures to linker sets. When
31 * this module is loaded, it iterates over all of the loaded modules and
32 * registers probes and providers with the DTrace framework based on the
33 * contents of these linker sets.
35 * A list of SDT providers is maintained here since a provider may span multiple
36 * modules. When a kernel module is unloaded, a provider defined in that module
37 * is unregistered only if no other modules refer to it. The DTrace framework is
38 * responsible for destroying individual probes when a kernel module is
39 * unloaded; in particular, probes may not span multiple kernel modules.
42 #include <sys/cdefs.h>
43 #include <sys/param.h>
44 #include <sys/systm.h>
47 #include <sys/eventhandler.h>
48 #include <sys/kernel.h>
49 #include <sys/limits.h>
50 #include <sys/linker.h>
51 #include <sys/linker_set.h>
53 #include <sys/lockstat.h>
54 #include <sys/malloc.h>
55 #include <sys/module.h>
56 #include <sys/mutex.h>
57 #include <sys/queue.h>
60 #include <sys/dtrace.h>
61 #include <sys/dtrace_bsd.h>
64 static void sdt_getargdesc(void *, dtrace_id_t, void *, dtrace_argdesc_t *);
65 static void sdt_provide_probes(void *, dtrace_probedesc_t *);
66 static void sdt_destroy(void *, dtrace_id_t, void *);
67 static void sdt_enable(void *, dtrace_id_t, void *);
68 static void sdt_disable(void *, dtrace_id_t, void *);
70 static void sdt_load(void);
71 static int sdt_unload(void);
72 static void sdt_create_provider(struct sdt_provider *);
73 static void sdt_create_probe(struct sdt_probe *);
74 static void sdt_kld_load(void *, struct linker_file *);
75 static void sdt_kld_unload_try(void *, struct linker_file *, int *);
77 static MALLOC_DEFINE(M_SDT, "SDT", "DTrace SDT providers");
79 static int sdt_probes_enabled_count;
80 static int lockstat_enabled_count;
82 static dtrace_pattr_t sdt_attr = {
83 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
84 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
85 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
86 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
87 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
90 static dtrace_pops_t sdt_pops = {
91 .dtps_provide = sdt_provide_probes,
92 .dtps_provide_module = NULL,
93 .dtps_enable = sdt_enable,
94 .dtps_disable = sdt_disable,
97 .dtps_getargdesc = sdt_getargdesc,
98 .dtps_getargval = NULL,
99 .dtps_usermode = NULL,
100 .dtps_destroy = sdt_destroy,
103 static TAILQ_HEAD(, sdt_provider) sdt_prov_list;
105 static eventhandler_tag sdt_kld_load_tag;
106 static eventhandler_tag sdt_kld_unload_try_tag;
109 sdt_create_provider(struct sdt_provider *prov)
111 struct sdt_provider *curr, *newprov;
113 TAILQ_FOREACH(curr, &sdt_prov_list, prov_entry)
114 if (strcmp(prov->name, curr->name) == 0) {
115 /* The provider has already been defined. */
121 * Make a copy of prov so that we don't lose fields if its module is
122 * unloaded but the provider isn't destroyed. This could happen with
123 * a provider that spans multiple modules.
125 newprov = malloc(sizeof(*newprov), M_SDT, M_WAITOK | M_ZERO);
126 newprov->name = strdup(prov->name, M_SDT);
127 prov->sdt_refs = newprov->sdt_refs = 1;
129 TAILQ_INSERT_TAIL(&sdt_prov_list, newprov, prov_entry);
131 (void)dtrace_register(newprov->name, &sdt_attr, DTRACE_PRIV_USER, NULL,
132 &sdt_pops, NULL, (dtrace_provider_id_t *)&newprov->id);
133 prov->id = newprov->id;
137 sdt_create_probe(struct sdt_probe *probe)
139 struct sdt_provider *prov;
140 char mod[DTRACE_MODNAMELEN];
141 char func[DTRACE_FUNCNAMELEN];
142 char name[DTRACE_NAMELEN];
147 if (probe->version != (int)sizeof(*probe)) {
148 printf("ignoring probe %p, version %u expected %u\n",
149 probe, probe->version, (int)sizeof(*probe));
153 TAILQ_FOREACH(prov, &sdt_prov_list, prov_entry)
154 if (strcmp(prov->name, probe->prov->name) == 0)
157 KASSERT(prov != NULL, ("probe defined without a provider"));
159 /* If no module name was specified, use the module filename. */
160 if (*probe->mod == 0) {
161 len = strlcpy(mod, probe->sdtp_lf->filename, sizeof(mod));
162 if (len > 3 && strcmp(mod + len - 3, ".ko") == 0)
165 strlcpy(mod, probe->mod, sizeof(mod));
168 * Unfortunately this is necessary because the Solaris DTrace
169 * code mixes consts and non-consts with casts to override
170 * the incompatibilies. On FreeBSD, we use strict warnings
171 * in the C compiler, so we have to respect const vs non-const.
173 strlcpy(func, probe->func, sizeof(func));
175 strcpy(func, "none");
179 for (len = 0; len < (sizeof(name) - 1) && *from != '\0';
180 len++, from++, to++) {
181 if (from[0] == '_' && from[1] == '_') {
189 if (dtrace_probe_lookup(prov->id, mod, func, name) != DTRACE_IDNONE)
192 (void)dtrace_probe_create(prov->id, mod, func, name, 1, probe);
196 * Probes are created through the SDT module load/unload hook, so this function
197 * has nothing to do. It only exists because the DTrace provider framework
198 * requires one of provide_probes and provide_module to be defined.
201 sdt_provide_probes(void *arg, dtrace_probedesc_t *desc)
206 sdt_enable(void *arg __unused, dtrace_id_t id, void *parg)
208 struct sdt_probe *probe = parg;
211 probe->sdtp_lf->nenabled++;
212 if (strcmp(probe->prov->name, "lockstat") == 0) {
213 lockstat_enabled_count++;
214 if (lockstat_enabled_count == 1)
215 lockstat_enabled = true;
217 sdt_probes_enabled_count++;
218 if (sdt_probes_enabled_count == 1)
219 sdt_probes_enabled = true;
223 sdt_disable(void *arg __unused, dtrace_id_t id, void *parg)
225 struct sdt_probe *probe = parg;
227 KASSERT(probe->sdtp_lf->nenabled > 0, ("no probes enabled"));
229 sdt_probes_enabled_count--;
230 if (sdt_probes_enabled_count == 0)
231 sdt_probes_enabled = false;
232 if (strcmp(probe->prov->name, "lockstat") == 0) {
233 lockstat_enabled_count--;
234 if (lockstat_enabled_count == 0)
235 lockstat_enabled = false;
238 probe->sdtp_lf->nenabled--;
242 sdt_getargdesc(void *arg, dtrace_id_t id, void *parg, dtrace_argdesc_t *desc)
244 struct sdt_argtype *argtype;
245 struct sdt_probe *probe = parg;
247 if (desc->dtargd_ndx >= probe->n_args) {
248 desc->dtargd_ndx = DTRACE_ARGNONE;
252 TAILQ_FOREACH(argtype, &probe->argtype_list, argtype_entry) {
253 if (desc->dtargd_ndx == argtype->ndx) {
254 desc->dtargd_mapping = desc->dtargd_ndx;
255 if (argtype->type == NULL) {
256 desc->dtargd_native[0] = '\0';
257 desc->dtargd_xlate[0] = '\0';
260 strlcpy(desc->dtargd_native, argtype->type,
261 sizeof(desc->dtargd_native));
262 if (argtype->xtype != NULL)
263 strlcpy(desc->dtargd_xlate, argtype->xtype,
264 sizeof(desc->dtargd_xlate));
270 sdt_destroy(void *arg, dtrace_id_t id, void *parg)
275 * Called from the kernel linker when a module is loaded, before
276 * dtrace_module_loaded() is called. This is done so that it's possible to
277 * register new providers when modules are loaded. The DTrace framework
278 * explicitly disallows calling into the framework from the provide_module
279 * provider method, so we cannot do this there.
282 sdt_kld_load(void *arg __unused, struct linker_file *lf)
284 struct sdt_provider **prov, **begin, **end;
285 struct sdt_probe **probe, **p_begin, **p_end;
286 struct sdt_argtype **argtype, **a_begin, **a_end;
288 if (linker_file_lookup_set(lf, "sdt_providers_set", &begin, &end,
290 for (prov = begin; prov < end; prov++)
291 sdt_create_provider(*prov);
294 if (linker_file_lookup_set(lf, "sdt_probes_set", &p_begin, &p_end,
296 for (probe = p_begin; probe < p_end; probe++) {
297 (*probe)->sdtp_lf = lf;
298 sdt_create_probe(*probe);
299 TAILQ_INIT(&(*probe)->argtype_list);
303 if (linker_file_lookup_set(lf, "sdt_argtypes_set", &a_begin, &a_end,
305 for (argtype = a_begin; argtype < a_end; argtype++) {
306 (*argtype)->probe->n_args++;
307 TAILQ_INSERT_TAIL(&(*argtype)->probe->argtype_list,
308 *argtype, argtype_entry);
314 sdt_kld_unload_try(void *arg __unused, struct linker_file *lf, int *error)
316 struct sdt_provider *prov, **curr, **begin, **end, *tmp;
319 /* We already have an error, so don't do anything. */
321 else if (linker_file_lookup_set(lf, "sdt_providers_set", &begin, &end,
323 /* No DTrace providers are declared in this file. */
327 * Go through all the providers declared in this linker file and
328 * unregister any that aren't declared in another loaded file.
330 for (curr = begin; curr < end; curr++) {
331 TAILQ_FOREACH_SAFE(prov, &sdt_prov_list, prov_entry, tmp) {
332 if (strcmp(prov->name, (*curr)->name) != 0)
335 if (prov->sdt_refs == 1) {
336 if (dtrace_unregister(prov->id) != 0) {
340 TAILQ_REMOVE(&sdt_prov_list, prov, prov_entry);
341 free(prov->name, M_SDT);
351 sdt_linker_file_cb(linker_file_t lf, void *arg __unused)
354 sdt_kld_load(NULL, lf);
363 TAILQ_INIT(&sdt_prov_list);
365 sdt_probe_func = dtrace_probe;
367 sdt_kld_load_tag = EVENTHANDLER_REGISTER(kld_load, sdt_kld_load, NULL,
368 EVENTHANDLER_PRI_ANY);
369 sdt_kld_unload_try_tag = EVENTHANDLER_REGISTER(kld_unload_try,
370 sdt_kld_unload_try, NULL, EVENTHANDLER_PRI_ANY);
372 /* Pick up probes from the kernel and already-loaded linker files. */
373 linker_file_foreach(sdt_linker_file_cb, NULL);
379 struct sdt_provider *prov, *tmp;
382 EVENTHANDLER_DEREGISTER(kld_load, sdt_kld_load_tag);
383 EVENTHANDLER_DEREGISTER(kld_unload_try, sdt_kld_unload_try_tag);
385 sdt_probe_func = sdt_probe_stub;
387 TAILQ_FOREACH_SAFE(prov, &sdt_prov_list, prov_entry, tmp) {
388 ret = dtrace_unregister(prov->id);
391 TAILQ_REMOVE(&sdt_prov_list, prov, prov_entry);
392 free(prov->name, M_SDT);
400 sdt_modevent(module_t mod __unused, int type, void *data __unused)
413 SYSINIT(sdt_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, sdt_load, NULL);
414 SYSUNINIT(sdt_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, sdt_unload, NULL);
416 DEV_MODULE(sdt, sdt_modevent, NULL);
417 MODULE_VERSION(sdt, 1);
418 MODULE_DEPEND(sdt, dtrace, 1, 1, 1);