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/endian.h>
48 #include <sys/eventhandler.h>
49 #include <sys/kernel.h>
50 #include <sys/limits.h>
51 #include <sys/linker.h>
52 #include <sys/linker_set.h>
54 #include <sys/lockstat.h>
55 #include <sys/malloc.h>
56 #include <sys/module.h>
57 #include <sys/mutex.h>
58 #include <sys/queue.h>
61 #include <sys/dtrace.h>
62 #include <sys/dtrace_bsd.h>
65 static void sdt_getargdesc(void *, dtrace_id_t, void *, dtrace_argdesc_t *);
66 static void sdt_provide_probes(void *, dtrace_probedesc_t *);
67 static void sdt_destroy(void *, dtrace_id_t, void *);
68 static void sdt_enable(void *, dtrace_id_t, void *);
69 static void sdt_disable(void *, dtrace_id_t, void *);
71 static void sdt_load(void);
72 static int sdt_unload(void);
73 static void sdt_create_provider(struct sdt_provider *);
74 static void sdt_create_probe(struct sdt_probe *);
75 static void sdt_kld_load(void *, struct linker_file *);
76 static void sdt_kld_unload_try(void *, struct linker_file *, int *);
78 static MALLOC_DEFINE(M_SDT, "SDT", "DTrace SDT providers");
80 static int sdt_probes_enabled_count;
81 static int lockstat_enabled_count;
83 static dtrace_pattr_t sdt_attr = {
84 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
85 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
86 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
87 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
88 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
91 static dtrace_pops_t sdt_pops = {
92 .dtps_provide = sdt_provide_probes,
93 .dtps_provide_module = NULL,
94 .dtps_enable = sdt_enable,
95 .dtps_disable = sdt_disable,
98 .dtps_getargdesc = sdt_getargdesc,
99 .dtps_getargval = NULL,
100 .dtps_usermode = NULL,
101 .dtps_destroy = sdt_destroy,
104 static TAILQ_HEAD(, sdt_provider) sdt_prov_list;
106 static eventhandler_tag sdt_kld_load_tag;
107 static eventhandler_tag sdt_kld_unload_try_tag;
110 sdt_create_provider(struct sdt_provider *prov)
112 struct sdt_provider *curr, *newprov;
114 TAILQ_FOREACH(curr, &sdt_prov_list, prov_entry)
115 if (strcmp(prov->name, curr->name) == 0) {
116 /* The provider has already been defined. */
122 * Make a copy of prov so that we don't lose fields if its module is
123 * unloaded but the provider isn't destroyed. This could happen with
124 * a provider that spans multiple modules.
126 newprov = malloc(sizeof(*newprov), M_SDT, M_WAITOK | M_ZERO);
127 newprov->name = strdup(prov->name, M_SDT);
128 prov->sdt_refs = newprov->sdt_refs = 1;
130 TAILQ_INSERT_TAIL(&sdt_prov_list, newprov, prov_entry);
132 (void)dtrace_register(newprov->name, &sdt_attr, DTRACE_PRIV_USER, NULL,
133 &sdt_pops, NULL, (dtrace_provider_id_t *)&newprov->id);
134 prov->id = newprov->id;
138 sdt_create_probe(struct sdt_probe *probe)
140 struct sdt_provider *prov;
141 char mod[DTRACE_MODNAMELEN];
142 char func[DTRACE_FUNCNAMELEN];
143 char name[DTRACE_NAMELEN];
148 if (probe->version != (int)sizeof(*probe)) {
149 printf("ignoring probe %p, version %u expected %u\n",
150 probe, probe->version, (int)sizeof(*probe));
154 TAILQ_FOREACH(prov, &sdt_prov_list, prov_entry)
155 if (strcmp(prov->name, probe->prov->name) == 0)
158 KASSERT(prov != NULL, ("probe defined without a provider"));
160 /* If no module name was specified, use the module filename. */
161 if (*probe->mod == 0) {
162 len = strlcpy(mod, probe->sdtp_lf->filename, sizeof(mod));
163 if (len > 3 && strcmp(mod + len - 3, ".ko") == 0)
166 strlcpy(mod, probe->mod, sizeof(mod));
169 * Unfortunately this is necessary because the Solaris DTrace
170 * code mixes consts and non-consts with casts to override
171 * the incompatibilies. On FreeBSD, we use strict warnings
172 * in the C compiler, so we have to respect const vs non-const.
174 strlcpy(func, probe->func, sizeof(func));
176 strcpy(func, "none");
180 for (len = 0; len < (sizeof(name) - 1) && *from != '\0';
181 len++, from++, to++) {
182 if (from[0] == '_' && from[1] == '_') {
190 if (dtrace_probe_lookup(prov->id, mod, func, name) != DTRACE_IDNONE)
193 (void)dtrace_probe_create(prov->id, mod, func, name, 1, probe);
197 * Probes are created through the SDT module load/unload hook, so this function
198 * has nothing to do. It only exists because the DTrace provider framework
199 * requires one of provide_probes and provide_module to be defined.
202 sdt_provide_probes(void *arg, dtrace_probedesc_t *desc)
207 sdt_enable(void *arg __unused, dtrace_id_t id, void *parg)
209 struct sdt_probe *probe = parg;
212 probe->sdtp_lf->nenabled++;
213 if (strcmp(probe->prov->name, "lockstat") == 0) {
214 lockstat_enabled_count++;
215 if (lockstat_enabled_count == 1)
216 lockstat_enabled = true;
218 sdt_probes_enabled_count++;
219 if (sdt_probes_enabled_count == 1)
220 sdt_probes_enabled = true;
224 sdt_disable(void *arg __unused, dtrace_id_t id, void *parg)
226 struct sdt_probe *probe = parg;
228 KASSERT(probe->sdtp_lf->nenabled > 0, ("no probes enabled"));
230 sdt_probes_enabled_count--;
231 if (sdt_probes_enabled_count == 0)
232 sdt_probes_enabled = false;
233 if (strcmp(probe->prov->name, "lockstat") == 0) {
234 lockstat_enabled_count--;
235 if (lockstat_enabled_count == 0)
236 lockstat_enabled = false;
239 probe->sdtp_lf->nenabled--;
243 sdt_getargdesc(void *arg, dtrace_id_t id, void *parg, dtrace_argdesc_t *desc)
245 struct sdt_argtype *argtype;
246 struct sdt_probe *probe = parg;
248 if (desc->dtargd_ndx >= probe->n_args) {
249 desc->dtargd_ndx = DTRACE_ARGNONE;
253 TAILQ_FOREACH(argtype, &probe->argtype_list, argtype_entry) {
254 if (desc->dtargd_ndx == argtype->ndx) {
255 desc->dtargd_mapping = desc->dtargd_ndx;
256 if (argtype->type == NULL) {
257 desc->dtargd_native[0] = '\0';
258 desc->dtargd_xlate[0] = '\0';
261 strlcpy(desc->dtargd_native, argtype->type,
262 sizeof(desc->dtargd_native));
263 if (argtype->xtype != NULL)
264 strlcpy(desc->dtargd_xlate, argtype->xtype,
265 sizeof(desc->dtargd_xlate));
271 sdt_destroy(void *arg, dtrace_id_t id, void *parg)
276 * Called from the kernel linker when a module is loaded, before
277 * dtrace_module_loaded() is called. This is done so that it's possible to
278 * register new providers when modules are loaded. The DTrace framework
279 * explicitly disallows calling into the framework from the provide_module
280 * provider method, so we cannot do this there.
283 sdt_kld_load(void *arg __unused, struct linker_file *lf)
285 struct sdt_provider **prov, **begin, **end;
286 struct sdt_probe **probe, **p_begin, **p_end;
287 struct sdt_argtype **argtype, **a_begin, **a_end;
289 if (linker_file_lookup_set(lf, "sdt_providers_set", &begin, &end,
291 for (prov = begin; prov < end; prov++)
292 sdt_create_provider(*prov);
295 if (linker_file_lookup_set(lf, "sdt_probes_set", &p_begin, &p_end,
297 for (probe = p_begin; probe < p_end; probe++) {
298 (*probe)->sdtp_lf = lf;
299 sdt_create_probe(*probe);
300 TAILQ_INIT(&(*probe)->argtype_list);
304 if (linker_file_lookup_set(lf, "sdt_argtypes_set", &a_begin, &a_end,
306 for (argtype = a_begin; argtype < a_end; argtype++) {
307 (*argtype)->probe->n_args++;
308 TAILQ_INSERT_TAIL(&(*argtype)->probe->argtype_list,
309 *argtype, argtype_entry);
315 sdt_kld_unload_try(void *arg __unused, struct linker_file *lf, int *error)
317 struct sdt_provider *prov, **curr, **begin, **end, *tmp;
320 /* We already have an error, so don't do anything. */
322 else if (linker_file_lookup_set(lf, "sdt_providers_set", &begin, &end,
324 /* No DTrace providers are declared in this file. */
328 * Go through all the providers declared in this linker file and
329 * unregister any that aren't declared in another loaded file.
331 for (curr = begin; curr < end; curr++) {
332 TAILQ_FOREACH_SAFE(prov, &sdt_prov_list, prov_entry, tmp) {
333 if (strcmp(prov->name, (*curr)->name) != 0)
336 if (prov->sdt_refs == 1) {
337 if (dtrace_unregister(prov->id) != 0) {
341 TAILQ_REMOVE(&sdt_prov_list, prov, prov_entry);
342 free(prov->name, M_SDT);
352 sdt_linker_file_cb(linker_file_t lf, void *arg __unused)
355 sdt_kld_load(NULL, lf);
364 TAILQ_INIT(&sdt_prov_list);
366 sdt_probe_func = dtrace_probe;
368 sdt_kld_load_tag = EVENTHANDLER_REGISTER(kld_load, sdt_kld_load, NULL,
369 EVENTHANDLER_PRI_ANY);
370 sdt_kld_unload_try_tag = EVENTHANDLER_REGISTER(kld_unload_try,
371 sdt_kld_unload_try, NULL, EVENTHANDLER_PRI_ANY);
373 /* Pick up probes from the kernel and already-loaded linker files. */
374 linker_file_foreach(sdt_linker_file_cb, NULL);
380 struct sdt_provider *prov, *tmp;
383 EVENTHANDLER_DEREGISTER(kld_load, sdt_kld_load_tag);
384 EVENTHANDLER_DEREGISTER(kld_unload_try, sdt_kld_unload_try_tag);
386 sdt_probe_func = sdt_probe_stub;
388 TAILQ_FOREACH_SAFE(prov, &sdt_prov_list, prov_entry, tmp) {
389 ret = dtrace_unregister(prov->id);
392 TAILQ_REMOVE(&sdt_prov_list, prov, prov_entry);
393 free(prov->name, M_SDT);
401 sdt_modevent(module_t mod __unused, int type, void *data __unused)
414 SYSINIT(sdt_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, sdt_load, NULL);
415 SYSUNINIT(sdt_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, sdt_unload, NULL);
417 DEV_MODULE(sdt, sdt_modevent, NULL);
418 MODULE_VERSION(sdt, 1);
419 MODULE_DEPEND(sdt, dtrace, 1, 1, 1);