xref: /freebsd/sys/cddl/dev/profile/profile.c (revision d8a0fe102c0cfdfcd5b818f850eff09d8536c9bc)
1 /*
2  * CDDL HEADER START
3  *
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.
7  *
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.
12  *
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]
18  *
19  * CDDL HEADER END
20  *
21  * Portions Copyright 2006-2008 John Birrell jb@freebsd.org
22  *
23  * $FreeBSD$
24  *
25  */
26 
27 /*
28  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
29  * Use is subject to license terms.
30  */
31 
32 #include <sys/cdefs.h>
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/conf.h>
36 #include <sys/cpuvar.h>
37 #include <sys/fcntl.h>
38 #include <sys/filio.h>
39 #include <sys/kdb.h>
40 #include <sys/kernel.h>
41 #include <sys/kmem.h>
42 #include <sys/kthread.h>
43 #include <sys/limits.h>
44 #include <sys/linker.h>
45 #include <sys/lock.h>
46 #include <sys/malloc.h>
47 #include <sys/module.h>
48 #include <sys/mutex.h>
49 #include <sys/poll.h>
50 #include <sys/proc.h>
51 #include <sys/selinfo.h>
52 #include <sys/smp.h>
53 #include <sys/sysctl.h>
54 #include <sys/uio.h>
55 #include <sys/unistd.h>
56 #include <machine/cpu.h>
57 #include <machine/stdarg.h>
58 
59 #include <sys/dtrace.h>
60 #include <sys/dtrace_bsd.h>
61 
62 #define	PROF_NAMELEN		15
63 
64 #define	PROF_PROFILE		0
65 #define	PROF_TICK		1
66 #define	PROF_PREFIX_PROFILE	"profile-"
67 #define	PROF_PREFIX_TICK	"tick-"
68 
69 /*
70  * Regardless of platform, there are five artificial frames in the case of the
71  * profile provider:
72  *
73  *	profile_fire
74  *	cyclic_expire
75  *	cyclic_fire
76  *	[ cbe ]
77  *	[ locore ]
78  *
79  * On amd64, there are two frames associated with locore:  one in locore, and
80  * another in common interrupt dispatch code.  (i386 has not been modified to
81  * use this common layer.)  Further, on i386, the interrupted instruction
82  * appears as its own stack frame.  All of this means that we need to add one
83  * frame for amd64, and then take one away for both amd64 and i386.
84  *
85  * On SPARC, the picture is further complicated because the compiler
86  * optimizes away tail-calls -- so the following frames are optimized away:
87  *
88  * 	profile_fire
89  *	cyclic_expire
90  *
91  * This gives three frames.  However, on DEBUG kernels, the cyclic_expire
92  * frame cannot be tail-call eliminated, yielding four frames in this case.
93  *
94  * All of the above constraints lead to the mess below.  Yes, the profile
95  * provider should ideally figure this out on-the-fly by hiting one of its own
96  * probes and then walking its own stack trace.  This is complicated, however,
97  * and the static definition doesn't seem to be overly brittle.  Still, we
98  * allow for a manual override in case we get it completely wrong.
99  */
100 #ifdef __amd64
101 #define	PROF_ARTIFICIAL_FRAMES	10
102 #else
103 #ifdef __i386
104 #define	PROF_ARTIFICIAL_FRAMES	6
105 #else
106 #ifdef __sparc
107 #ifdef DEBUG
108 #define	PROF_ARTIFICIAL_FRAMES	4
109 #else
110 #define	PROF_ARTIFICIAL_FRAMES	3
111 #endif
112 #endif
113 #endif
114 #endif
115 
116 #ifdef __mips
117 /*
118  * This value is bogus just to make module compilable on mips
119  */
120 #define	PROF_ARTIFICIAL_FRAMES	3
121 #endif
122 
123 #ifdef __powerpc__
124 /*
125  * This value is bogus just to make module compilable on powerpc
126  */
127 #define	PROF_ARTIFICIAL_FRAMES	12
128 #endif
129 
130 struct profile_probe_percpu;
131 
132 #ifdef __mips
133 /* bogus */
134 #define	PROF_ARTIFICIAL_FRAMES	3
135 #endif
136 
137 #ifdef __arm__
138 #define	PROF_ARTIFICIAL_FRAMES	3
139 #endif
140 
141 #ifdef __aarch64__
142 /* TODO: verify */
143 #define	PROF_ARTIFICIAL_FRAMES	10
144 #endif
145 
146 #ifdef __riscv
147 /* TODO: verify */
148 #define	PROF_ARTIFICIAL_FRAMES	10
149 #endif
150 
151 typedef struct profile_probe {
152 	char		prof_name[PROF_NAMELEN];
153 	dtrace_id_t	prof_id;
154 	int		prof_kind;
155 #ifdef illumos
156 	hrtime_t	prof_interval;
157 	cyclic_id_t	prof_cyclic;
158 #else
159 	sbintime_t	prof_interval;
160 	struct callout	prof_cyclic;
161 	sbintime_t	prof_expected;
162 	struct profile_probe_percpu **prof_pcpus;
163 #endif
164 } profile_probe_t;
165 
166 typedef struct profile_probe_percpu {
167 	hrtime_t	profc_expected;
168 	hrtime_t	profc_interval;
169 	profile_probe_t	*profc_probe;
170 #ifdef __FreeBSD__
171 	struct callout	profc_cyclic;
172 #endif
173 } profile_probe_percpu_t;
174 
175 static d_open_t	profile_open;
176 static int	profile_unload(void);
177 static void	profile_create(hrtime_t, char *, int);
178 static void	profile_destroy(void *, dtrace_id_t, void *);
179 static void	profile_enable(void *, dtrace_id_t, void *);
180 static void	profile_disable(void *, dtrace_id_t, void *);
181 static void	profile_load(void *);
182 static void	profile_provide(void *, dtrace_probedesc_t *);
183 
184 static int profile_rates[] = {
185     97, 199, 499, 997, 1999,
186     4001, 4999, 0, 0, 0,
187     0, 0, 0, 0, 0,
188     0, 0, 0, 0, 0
189 };
190 
191 static int profile_ticks[] = {
192     1, 10, 100, 500, 1000,
193     5000, 0, 0, 0, 0,
194     0, 0, 0, 0, 0
195 };
196 
197 /*
198  * profile_max defines the upper bound on the number of profile probes that
199  * can exist (this is to prevent malicious or clumsy users from exhausing
200  * system resources by creating a slew of profile probes). At mod load time,
201  * this gets its value from PROFILE_MAX_DEFAULT or profile-max-probes if it's
202  * present in the profile.conf file.
203  */
204 #define	PROFILE_MAX_DEFAULT	1000	/* default max. number of probes */
205 static uint32_t profile_max = PROFILE_MAX_DEFAULT;
206 					/* maximum number of profile probes */
207 static uint32_t profile_total;		/* current number of profile probes */
208 
209 static struct cdevsw profile_cdevsw = {
210 	.d_version	= D_VERSION,
211 	.d_open		= profile_open,
212 	.d_name		= "profile",
213 };
214 
215 static dtrace_pattr_t profile_attr = {
216 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
217 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
218 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
219 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
220 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_ISA },
221 };
222 
223 static dtrace_pops_t profile_pops = {
224 	.dtps_provide =		profile_provide,
225 	.dtps_provide_module =	NULL,
226 	.dtps_enable =		profile_enable,
227 	.dtps_disable =		profile_disable,
228 	.dtps_suspend =		NULL,
229 	.dtps_resume =		NULL,
230 	.dtps_getargdesc =	NULL,
231 	.dtps_getargval =	NULL,
232 	.dtps_usermode =	NULL,
233 	.dtps_destroy =		profile_destroy
234 };
235 
236 static struct cdev		*profile_cdev;
237 static dtrace_provider_id_t	profile_id;
238 static hrtime_t			profile_interval_min = NANOSEC / 5000;	/* 5000 hz */
239 static int			profile_aframes = PROF_ARTIFICIAL_FRAMES;
240 
241 SYSCTL_DECL(_kern_dtrace);
242 SYSCTL_NODE(_kern_dtrace, OID_AUTO, profile, CTLFLAG_RD, 0, "DTrace profile parameters");
243 SYSCTL_INT(_kern_dtrace_profile, OID_AUTO, aframes, CTLFLAG_RW, &profile_aframes,
244     0, "Skipped frames for profile provider");
245 
246 static sbintime_t
247 nsec_to_sbt(hrtime_t nsec)
248 {
249 	time_t sec;
250 
251 	/*
252 	 * We need to calculate nsec * 2^32 / 10^9
253 	 * Seconds and nanoseconds are split to avoid overflow.
254 	 */
255 	sec = nsec / NANOSEC;
256 	nsec = nsec % NANOSEC;
257 	return (((sbintime_t)sec << 32) | ((sbintime_t)nsec << 32) / NANOSEC);
258 }
259 
260 static hrtime_t
261 sbt_to_nsec(sbintime_t sbt)
262 {
263 
264 	return ((sbt >> 32) * NANOSEC +
265 	    (((uint32_t)sbt * (hrtime_t)NANOSEC) >> 32));
266 }
267 
268 static void
269 profile_probe(profile_probe_t *prof, hrtime_t late)
270 {
271 	struct thread *td;
272 	struct trapframe *frame;
273 	uintfptr_t pc, upc;
274 
275 	td = curthread;
276 	pc = upc = 0;
277 
278 	/*
279 	 * td_intr_frame can be unset if this is a catch-up event upon waking up
280 	 * from idle sleep. This can only happen on a CPU idle thread. Use a
281 	 * representative arg0 value in this case so that one of the probe
282 	 * arguments is non-zero.
283 	 */
284 	frame = td->td_intr_frame;
285 	if (frame != NULL) {
286 		if (TRAPF_USERMODE(frame))
287 			upc = TRAPF_PC(frame);
288 		else
289 			pc = TRAPF_PC(frame);
290 	} else if (TD_IS_IDLETHREAD(td))
291 		pc = (uintfptr_t)&cpu_idle;
292 
293 	dtrace_probe(prof->prof_id, pc, upc, late, 0, 0);
294 }
295 
296 static void
297 profile_fire(void *arg)
298 {
299 	profile_probe_percpu_t *pcpu = arg;
300 	profile_probe_t *prof = pcpu->profc_probe;
301 	hrtime_t late;
302 
303 	late = sbt_to_nsec(sbinuptime() - pcpu->profc_expected);
304 
305 	profile_probe(prof, late);
306 	pcpu->profc_expected += pcpu->profc_interval;
307 	callout_schedule_sbt_curcpu(&pcpu->profc_cyclic,
308 	    pcpu->profc_expected, 0, C_DIRECT_EXEC | C_ABSOLUTE);
309 }
310 
311 static void
312 profile_tick(void *arg)
313 {
314 	profile_probe_t *prof = arg;
315 
316 	profile_probe(prof, 0);
317 	prof->prof_expected += prof->prof_interval;
318 	callout_schedule_sbt(&prof->prof_cyclic,
319 	    prof->prof_expected, 0, C_DIRECT_EXEC | C_ABSOLUTE);
320 }
321 
322 static void
323 profile_create(hrtime_t interval, char *name, int kind)
324 {
325 	profile_probe_t *prof;
326 
327 	if (interval < profile_interval_min)
328 		return;
329 
330 	if (dtrace_probe_lookup(profile_id, NULL, NULL, name) != 0)
331 		return;
332 
333 	atomic_add_32(&profile_total, 1);
334 	if (profile_total > profile_max) {
335 		atomic_add_32(&profile_total, -1);
336 		return;
337 	}
338 
339 	prof = kmem_zalloc(sizeof (profile_probe_t), KM_SLEEP);
340 	(void) strcpy(prof->prof_name, name);
341 #ifdef illumos
342 	prof->prof_interval = interval;
343 	prof->prof_cyclic = CYCLIC_NONE;
344 #else
345 	prof->prof_interval = nsec_to_sbt(interval);
346 	callout_init(&prof->prof_cyclic, 1);
347 #endif
348 	prof->prof_kind = kind;
349 	prof->prof_id = dtrace_probe_create(profile_id,
350 	    NULL, NULL, name,
351 	    profile_aframes, prof);
352 }
353 
354 /*ARGSUSED*/
355 static void
356 profile_provide(void *arg, dtrace_probedesc_t *desc)
357 {
358 	int i, j, rate, kind;
359 	hrtime_t val = 0, mult = 1, len = 0;
360 	char *name, *suffix = NULL;
361 
362 	const struct {
363 		char *prefix;
364 		int kind;
365 	} types[] = {
366 		{ PROF_PREFIX_PROFILE, PROF_PROFILE },
367 		{ PROF_PREFIX_TICK, PROF_TICK },
368 		{ 0, 0 }
369 	};
370 
371 	const struct {
372 		char *name;
373 		hrtime_t mult;
374 	} suffixes[] = {
375 		{ "ns", 	NANOSEC / NANOSEC },
376 		{ "nsec",	NANOSEC / NANOSEC },
377 		{ "us",		NANOSEC / MICROSEC },
378 		{ "usec",	NANOSEC / MICROSEC },
379 		{ "ms",		NANOSEC / MILLISEC },
380 		{ "msec",	NANOSEC / MILLISEC },
381 		{ "s",		NANOSEC / SEC },
382 		{ "sec",	NANOSEC / SEC },
383 		{ "m",		NANOSEC * (hrtime_t)60 },
384 		{ "min",	NANOSEC * (hrtime_t)60 },
385 		{ "h",		NANOSEC * (hrtime_t)(60 * 60) },
386 		{ "hour",	NANOSEC * (hrtime_t)(60 * 60) },
387 		{ "d",		NANOSEC * (hrtime_t)(24 * 60 * 60) },
388 		{ "day",	NANOSEC * (hrtime_t)(24 * 60 * 60) },
389 		{ "hz",		0 },
390 		{ NULL }
391 	};
392 
393 	if (desc == NULL) {
394 		char n[PROF_NAMELEN];
395 
396 		/*
397 		 * If no description was provided, provide all of our probes.
398 		 */
399 		for (i = 0; i < sizeof (profile_rates) / sizeof (int); i++) {
400 			if ((rate = profile_rates[i]) == 0)
401 				continue;
402 
403 			(void) snprintf(n, PROF_NAMELEN, "%s%d",
404 			    PROF_PREFIX_PROFILE, rate);
405 			profile_create(NANOSEC / rate, n, PROF_PROFILE);
406 		}
407 
408 		for (i = 0; i < sizeof (profile_ticks) / sizeof (int); i++) {
409 			if ((rate = profile_ticks[i]) == 0)
410 				continue;
411 
412 			(void) snprintf(n, PROF_NAMELEN, "%s%d",
413 			    PROF_PREFIX_TICK, rate);
414 			profile_create(NANOSEC / rate, n, PROF_TICK);
415 		}
416 
417 		return;
418 	}
419 
420 	name = desc->dtpd_name;
421 
422 	for (i = 0; types[i].prefix != NULL; i++) {
423 		len = strlen(types[i].prefix);
424 
425 		if (strncmp(name, types[i].prefix, len) != 0)
426 			continue;
427 		break;
428 	}
429 
430 	if (types[i].prefix == NULL)
431 		return;
432 
433 	kind = types[i].kind;
434 	j = strlen(name) - len;
435 
436 	/*
437 	 * We need to start before any time suffix.
438 	 */
439 	for (j = strlen(name); j >= len; j--) {
440 		if (name[j] >= '0' && name[j] <= '9')
441 			break;
442 		suffix = &name[j];
443 	}
444 
445 	ASSERT(suffix != NULL);
446 
447 	/*
448 	 * Now determine the numerical value present in the probe name.
449 	 */
450 	for (; j >= len; j--) {
451 		if (name[j] < '0' || name[j] > '9')
452 			return;
453 
454 		val += (name[j] - '0') * mult;
455 		mult *= (hrtime_t)10;
456 	}
457 
458 	if (val == 0)
459 		return;
460 
461 	/*
462 	 * Look-up the suffix to determine the multiplier.
463 	 */
464 	for (i = 0, mult = 0; suffixes[i].name != NULL; i++) {
465 		if (strcasecmp(suffixes[i].name, suffix) == 0) {
466 			mult = suffixes[i].mult;
467 			break;
468 		}
469 	}
470 
471 	if (suffixes[i].name == NULL && *suffix != '\0')
472 		return;
473 
474 	if (mult == 0) {
475 		/*
476 		 * The default is frequency-per-second.
477 		 */
478 		val = NANOSEC / val;
479 	} else {
480 		val *= mult;
481 	}
482 
483 	profile_create(val, name, kind);
484 }
485 
486 /* ARGSUSED */
487 static void
488 profile_destroy(void *arg, dtrace_id_t id, void *parg)
489 {
490 	profile_probe_t *prof = parg;
491 
492 #ifdef illumos
493 	ASSERT(prof->prof_cyclic == CYCLIC_NONE);
494 #else
495 	ASSERT(!callout_active(&prof->prof_cyclic) && prof->prof_pcpus == NULL);
496 #endif
497 	kmem_free(prof, sizeof (profile_probe_t));
498 
499 	ASSERT(profile_total >= 1);
500 	atomic_add_32(&profile_total, -1);
501 }
502 
503 #ifdef illumos
504 /*ARGSUSED*/
505 static void
506 profile_online(void *arg, cpu_t *cpu, cyc_handler_t *hdlr, cyc_time_t *when)
507 {
508 	profile_probe_t *prof = arg;
509 	profile_probe_percpu_t *pcpu;
510 
511 	pcpu = kmem_zalloc(sizeof (profile_probe_percpu_t), KM_SLEEP);
512 	pcpu->profc_probe = prof;
513 
514 	hdlr->cyh_func = profile_fire;
515 	hdlr->cyh_arg = pcpu;
516 
517 	when->cyt_interval = prof->prof_interval;
518 	when->cyt_when = gethrtime() + when->cyt_interval;
519 
520 	pcpu->profc_expected = when->cyt_when;
521 	pcpu->profc_interval = when->cyt_interval;
522 }
523 
524 /*ARGSUSED*/
525 static void
526 profile_offline(void *arg, cpu_t *cpu, void *oarg)
527 {
528 	profile_probe_percpu_t *pcpu = oarg;
529 
530 	ASSERT(pcpu->profc_probe == arg);
531 	kmem_free(pcpu, sizeof (profile_probe_percpu_t));
532 }
533 
534 /* ARGSUSED */
535 static void
536 profile_enable(void *arg, dtrace_id_t id, void *parg)
537 {
538 	profile_probe_t *prof = parg;
539 	cyc_omni_handler_t omni;
540 	cyc_handler_t hdlr;
541 	cyc_time_t when;
542 
543 	ASSERT(prof->prof_interval != 0);
544 	ASSERT(MUTEX_HELD(&cpu_lock));
545 
546 	if (prof->prof_kind == PROF_TICK) {
547 		hdlr.cyh_func = profile_tick;
548 		hdlr.cyh_arg = prof;
549 
550 		when.cyt_interval = prof->prof_interval;
551 		when.cyt_when = gethrtime() + when.cyt_interval;
552 	} else {
553 		ASSERT(prof->prof_kind == PROF_PROFILE);
554 		omni.cyo_online = profile_online;
555 		omni.cyo_offline = profile_offline;
556 		omni.cyo_arg = prof;
557 	}
558 
559 	if (prof->prof_kind == PROF_TICK) {
560 		prof->prof_cyclic = cyclic_add(&hdlr, &when);
561 	} else {
562 		prof->prof_cyclic = cyclic_add_omni(&omni);
563 	}
564 }
565 
566 /* ARGSUSED */
567 static void
568 profile_disable(void *arg, dtrace_id_t id, void *parg)
569 {
570 	profile_probe_t *prof = parg;
571 
572 	ASSERT(prof->prof_cyclic != CYCLIC_NONE);
573 	ASSERT(MUTEX_HELD(&cpu_lock));
574 
575 	cyclic_remove(prof->prof_cyclic);
576 	prof->prof_cyclic = CYCLIC_NONE;
577 }
578 
579 #else
580 
581 static void
582 profile_enable_omni(profile_probe_t *prof)
583 {
584 	profile_probe_percpu_t *pcpu;
585 	int cpu;
586 
587 	prof->prof_pcpus = kmem_zalloc((mp_maxid + 1) * sizeof(pcpu), KM_SLEEP);
588 	CPU_FOREACH(cpu) {
589 		pcpu = kmem_zalloc(sizeof(profile_probe_percpu_t), KM_SLEEP);
590 		prof->prof_pcpus[cpu] = pcpu;
591 		pcpu->profc_probe = prof;
592 		pcpu->profc_expected = sbinuptime() + prof->prof_interval;
593 		pcpu->profc_interval = prof->prof_interval;
594 		callout_init(&pcpu->profc_cyclic, 1);
595 		callout_reset_sbt_on(&pcpu->profc_cyclic,
596 		    pcpu->profc_expected, 0, profile_fire, pcpu,
597 		    cpu, C_DIRECT_EXEC | C_ABSOLUTE);
598 	}
599 }
600 
601 static void
602 profile_disable_omni(profile_probe_t *prof)
603 {
604 	profile_probe_percpu_t *pcpu;
605 	int cpu;
606 
607 	ASSERT(prof->prof_pcpus != NULL);
608 	CPU_FOREACH(cpu) {
609 		pcpu = prof->prof_pcpus[cpu];
610 		ASSERT(pcpu->profc_probe == prof);
611 		ASSERT(callout_active(&pcpu->profc_cyclic));
612 		callout_stop(&pcpu->profc_cyclic);
613 		callout_drain(&pcpu->profc_cyclic);
614 		kmem_free(pcpu, sizeof(profile_probe_percpu_t));
615 	}
616 	kmem_free(prof->prof_pcpus, (mp_maxid + 1) * sizeof(pcpu));
617 	prof->prof_pcpus = NULL;
618 }
619 
620 /* ARGSUSED */
621 static void
622 profile_enable(void *arg, dtrace_id_t id, void *parg)
623 {
624 	profile_probe_t *prof = parg;
625 
626 	if (prof->prof_kind == PROF_TICK) {
627 		prof->prof_expected = sbinuptime() + prof->prof_interval;
628 		callout_reset_sbt(&prof->prof_cyclic,
629 		    prof->prof_expected, 0, profile_tick, prof,
630 		    C_DIRECT_EXEC | C_ABSOLUTE);
631 	} else {
632 		ASSERT(prof->prof_kind == PROF_PROFILE);
633 		profile_enable_omni(prof);
634 	}
635 }
636 
637 /* ARGSUSED */
638 static void
639 profile_disable(void *arg, dtrace_id_t id, void *parg)
640 {
641 	profile_probe_t *prof = parg;
642 
643 	if (prof->prof_kind == PROF_TICK) {
644 		ASSERT(callout_active(&prof->prof_cyclic));
645 		callout_stop(&prof->prof_cyclic);
646 		callout_drain(&prof->prof_cyclic);
647 	} else {
648 		ASSERT(prof->prof_kind == PROF_PROFILE);
649 		profile_disable_omni(prof);
650 	}
651 }
652 #endif
653 
654 static void
655 profile_load(void *dummy)
656 {
657 	/* Create the /dev/dtrace/profile entry. */
658 	profile_cdev = make_dev(&profile_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
659 	    "dtrace/profile");
660 
661 	if (dtrace_register("profile", &profile_attr, DTRACE_PRIV_USER,
662 	    NULL, &profile_pops, NULL, &profile_id) != 0)
663 		return;
664 }
665 
666 
667 static int
668 profile_unload()
669 {
670 	int error = 0;
671 
672 	if ((error = dtrace_unregister(profile_id)) != 0)
673 		return (error);
674 
675 	destroy_dev(profile_cdev);
676 
677 	return (error);
678 }
679 
680 /* ARGSUSED */
681 static int
682 profile_modevent(module_t mod __unused, int type, void *data __unused)
683 {
684 	int error = 0;
685 
686 	switch (type) {
687 	case MOD_LOAD:
688 		break;
689 
690 	case MOD_UNLOAD:
691 		break;
692 
693 	case MOD_SHUTDOWN:
694 		break;
695 
696 	default:
697 		error = EOPNOTSUPP;
698 		break;
699 
700 	}
701 	return (error);
702 }
703 
704 /* ARGSUSED */
705 static int
706 profile_open(struct cdev *dev __unused, int oflags __unused, int devtype __unused, struct thread *td __unused)
707 {
708 	return (0);
709 }
710 
711 SYSINIT(profile_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, profile_load, NULL);
712 SYSUNINIT(profile_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, profile_unload, NULL);
713 
714 DEV_MODULE(profile, profile_modevent, NULL);
715 MODULE_VERSION(profile, 1);
716 MODULE_DEPEND(profile, dtrace, 1, 1, 1);
717 MODULE_DEPEND(profile, opensolaris, 1, 1, 1);
718