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/*
22 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26
27#include <sys/errno.h>
28#include <sys/stat.h>
29#include <sys/modctl.h>
30#include <sys/conf.h>
31#include <sys/systm.h>
32#include <sys/ddi.h>
33#include <sys/sunddi.h>
34#include <sys/cpuvar.h>
35#include <sys/kmem.h>
36#include <sys/strsubr.h>
37#include <sys/dtrace.h>
38#include <sys/cyclic.h>
39#include <sys/atomic.h>
40
41static dev_info_t *profile_devi;
42static dtrace_provider_id_t profile_id;
43
44/*
45 * Regardless of platform, the stack frames look like this in the case of the
46 * profile provider:
47 *
48 *	profile_fire
49 *	cyclic_expire
50 *	cyclic_fire
51 *	[ cbe ]
52 *	[ interrupt code ]
53 *
54 * On x86, there are five frames from the generic interrupt code; further, the
55 * interrupted instruction appears as its own stack frame, giving us a total of
56 * 10.
57 *
58 * On SPARC, the picture is further complicated because the compiler
59 * optimizes away tail-calls -- so the following frames are optimized away:
60 *
61 * 	profile_fire
62 *	cyclic_expire
63 *
64 * This gives three frames.  However, on DEBUG kernels, the cyclic_expire
65 * frame cannot be tail-call eliminated, yielding four frames in this case.
66 *
67 * All of the above constraints lead to the mess below.  Yes, the profile
68 * provider should ideally figure this out on-the-fly by hitting one of its own
69 * probes and then walking its own stack trace.  This is complicated, however,
70 * and the static definition doesn't seem to be overly brittle.  Still, we
71 * allow for a manual override in case we get it completely wrong.
72 */
73#ifdef __x86
74#define	PROF_ARTIFICIAL_FRAMES	10
75#else
76#ifdef __sparc
77#ifdef DEBUG
78#define	PROF_ARTIFICIAL_FRAMES	4
79#else
80#define	PROF_ARTIFICIAL_FRAMES	3
81#endif
82#endif
83#endif
84
85#define	PROF_NAMELEN		15
86
87#define	PROF_PROFILE		0
88#define	PROF_TICK		1
89#define	PROF_PREFIX_PROFILE	"profile-"
90#define	PROF_PREFIX_TICK	"tick-"
91
92typedef struct profile_probe {
93	char		prof_name[PROF_NAMELEN];
94	dtrace_id_t	prof_id;
95	int		prof_kind;
96	hrtime_t	prof_interval;
97	cyclic_id_t	prof_cyclic;
98} profile_probe_t;
99
100typedef struct profile_probe_percpu {
101	hrtime_t	profc_expected;
102	hrtime_t	profc_interval;
103	profile_probe_t	*profc_probe;
104} profile_probe_percpu_t;
105
106hrtime_t	profile_interval_min = NANOSEC / 5000;		/* 5000 hz */
107int		profile_aframes = 0;				/* override */
108
109static int profile_rates[] = {
110    97, 199, 499, 997, 1999,
111    4001, 4999, 0, 0, 0,
112    0, 0, 0, 0, 0,
113    0, 0, 0, 0, 0
114};
115
116static int profile_ticks[] = {
117    1, 10, 100, 500, 1000,
118    5000, 0, 0, 0, 0,
119    0, 0, 0, 0, 0
120};
121
122/*
123 * profile_max defines the upper bound on the number of profile probes that
124 * can exist (this is to prevent malicious or clumsy users from exhausing
125 * system resources by creating a slew of profile probes). At mod load time,
126 * this gets its value from PROFILE_MAX_DEFAULT or profile-max-probes if it's
127 * present in the profile.conf file.
128 */
129#define	PROFILE_MAX_DEFAULT	1000	/* default max. number of probes */
130static uint32_t profile_max;		/* maximum number of profile probes */
131static uint32_t profile_total;	/* current number of profile probes */
132
133static void
134profile_fire(void *arg)
135{
136	profile_probe_percpu_t *pcpu = arg;
137	profile_probe_t *prof = pcpu->profc_probe;
138	hrtime_t late;
139
140	late = dtrace_gethrtime() - pcpu->profc_expected;
141	pcpu->profc_expected += pcpu->profc_interval;
142
143	dtrace_probe(prof->prof_id, CPU->cpu_profile_pc,
144	    CPU->cpu_profile_upc, late, 0, 0);
145}
146
147static void
148profile_tick(void *arg)
149{
150	profile_probe_t *prof = arg;
151
152	dtrace_probe(prof->prof_id, CPU->cpu_profile_pc,
153	    CPU->cpu_profile_upc, 0, 0, 0);
154}
155
156static void
157profile_create(hrtime_t interval, const char *name, int kind)
158{
159	profile_probe_t *prof;
160	int nr_frames = PROF_ARTIFICIAL_FRAMES + dtrace_mach_aframes();
161
162	if (profile_aframes)
163		nr_frames = profile_aframes;
164
165	if (interval < profile_interval_min)
166		return;
167
168	if (dtrace_probe_lookup(profile_id, NULL, NULL, name) != 0)
169		return;
170
171	atomic_add_32(&profile_total, 1);
172	if (profile_total > profile_max) {
173		atomic_add_32(&profile_total, -1);
174		return;
175	}
176
177	prof = kmem_zalloc(sizeof (profile_probe_t), KM_SLEEP);
178	(void) strcpy(prof->prof_name, name);
179	prof->prof_interval = interval;
180	prof->prof_cyclic = CYCLIC_NONE;
181	prof->prof_kind = kind;
182	prof->prof_id = dtrace_probe_create(profile_id,
183	    NULL, NULL, name, nr_frames, prof);
184}
185
186/*ARGSUSED*/
187static void
188profile_provide(void *arg, const dtrace_probedesc_t *desc)
189{
190	int i, j, rate, kind;
191	hrtime_t val = 0, mult = 1, len;
192	const char *name, *suffix = NULL;
193
194	const struct {
195		char *prefix;
196		int kind;
197	} types[] = {
198		{ PROF_PREFIX_PROFILE, PROF_PROFILE },
199		{ PROF_PREFIX_TICK, PROF_TICK },
200		{ NULL, NULL }
201	};
202
203	const struct {
204		char *name;
205		hrtime_t mult;
206	} suffixes[] = {
207		{ "ns", 	NANOSEC / NANOSEC },
208		{ "nsec",	NANOSEC / NANOSEC },
209		{ "us",		NANOSEC / MICROSEC },
210		{ "usec",	NANOSEC / MICROSEC },
211		{ "ms",		NANOSEC / MILLISEC },
212		{ "msec",	NANOSEC / MILLISEC },
213		{ "s",		NANOSEC / SEC },
214		{ "sec",	NANOSEC / SEC },
215		{ "m",		NANOSEC * (hrtime_t)60 },
216		{ "min",	NANOSEC * (hrtime_t)60 },
217		{ "h",		NANOSEC * (hrtime_t)(60 * 60) },
218		{ "hour",	NANOSEC * (hrtime_t)(60 * 60) },
219		{ "d",		NANOSEC * (hrtime_t)(24 * 60 * 60) },
220		{ "day",	NANOSEC * (hrtime_t)(24 * 60 * 60) },
221		{ "hz",		0 },
222		{ NULL }
223	};
224
225	if (desc == NULL) {
226		char n[PROF_NAMELEN];
227
228		/*
229		 * If no description was provided, provide all of our probes.
230		 */
231		for (i = 0; i < sizeof (profile_rates) / sizeof (int); i++) {
232			if ((rate = profile_rates[i]) == 0)
233				continue;
234
235			(void) snprintf(n, PROF_NAMELEN, "%s%d",
236			    PROF_PREFIX_PROFILE, rate);
237			profile_create(NANOSEC / rate, n, PROF_PROFILE);
238		}
239
240		for (i = 0; i < sizeof (profile_ticks) / sizeof (int); i++) {
241			if ((rate = profile_ticks[i]) == 0)
242				continue;
243
244			(void) snprintf(n, PROF_NAMELEN, "%s%d",
245			    PROF_PREFIX_TICK, rate);
246			profile_create(NANOSEC / rate, n, PROF_TICK);
247		}
248
249		return;
250	}
251
252	name = desc->dtpd_name;
253
254	for (i = 0; types[i].prefix != NULL; i++) {
255		len = strlen(types[i].prefix);
256
257		if (strncmp(name, types[i].prefix, len) != 0)
258			continue;
259		break;
260	}
261
262	if (types[i].prefix == NULL)
263		return;
264
265	kind = types[i].kind;
266	j = strlen(name) - len;
267
268	/*
269	 * We need to start before any time suffix.
270	 */
271	for (j = strlen(name); j >= len; j--) {
272		if (name[j] >= '0' && name[j] <= '9')
273			break;
274		suffix = &name[j];
275	}
276
277	ASSERT(suffix != NULL);
278
279	/*
280	 * Now determine the numerical value present in the probe name.
281	 */
282	for (; j >= len; j--) {
283		if (name[j] < '0' || name[j] > '9')
284			return;
285
286		val += (name[j] - '0') * mult;
287		mult *= (hrtime_t)10;
288	}
289
290	if (val == 0)
291		return;
292
293	/*
294	 * Look-up the suffix to determine the multiplier.
295	 */
296	for (i = 0, mult = 0; suffixes[i].name != NULL; i++) {
297		if (strcasecmp(suffixes[i].name, suffix) == 0) {
298			mult = suffixes[i].mult;
299			break;
300		}
301	}
302
303	if (suffixes[i].name == NULL && *suffix != '\0')
304		return;
305
306	if (mult == 0) {
307		/*
308		 * The default is frequency-per-second.
309		 */
310		val = NANOSEC / val;
311	} else {
312		val *= mult;
313	}
314
315	profile_create(val, name, kind);
316}
317
318/*ARGSUSED*/
319static void
320profile_destroy(void *arg, dtrace_id_t id, void *parg)
321{
322	profile_probe_t *prof = parg;
323
324	ASSERT(prof->prof_cyclic == CYCLIC_NONE);
325	kmem_free(prof, sizeof (profile_probe_t));
326
327	ASSERT(profile_total >= 1);
328	atomic_add_32(&profile_total, -1);
329}
330
331/*ARGSUSED*/
332static void
333profile_online(void *arg, cpu_t *cpu, cyc_handler_t *hdlr, cyc_time_t *when)
334{
335	profile_probe_t *prof = arg;
336	profile_probe_percpu_t *pcpu;
337
338	pcpu = kmem_zalloc(sizeof (profile_probe_percpu_t), KM_SLEEP);
339	pcpu->profc_probe = prof;
340
341	hdlr->cyh_func = profile_fire;
342	hdlr->cyh_arg = pcpu;
343	hdlr->cyh_level = CY_HIGH_LEVEL;
344
345	when->cyt_interval = prof->prof_interval;
346	when->cyt_when = dtrace_gethrtime() + when->cyt_interval;
347
348	pcpu->profc_expected = when->cyt_when;
349	pcpu->profc_interval = when->cyt_interval;
350}
351
352/*ARGSUSED*/
353static void
354profile_offline(void *arg, cpu_t *cpu, void *oarg)
355{
356	profile_probe_percpu_t *pcpu = oarg;
357
358	ASSERT(pcpu->profc_probe == arg);
359	kmem_free(pcpu, sizeof (profile_probe_percpu_t));
360}
361
362/*ARGSUSED*/
363static int
364profile_enable(void *arg, dtrace_id_t id, void *parg)
365{
366	profile_probe_t *prof = parg;
367	cyc_omni_handler_t omni;
368	cyc_handler_t hdlr;
369	cyc_time_t when;
370
371	ASSERT(prof->prof_interval != 0);
372	ASSERT(MUTEX_HELD(&cpu_lock));
373
374	if (prof->prof_kind == PROF_TICK) {
375		hdlr.cyh_func = profile_tick;
376		hdlr.cyh_arg = prof;
377		hdlr.cyh_level = CY_HIGH_LEVEL;
378
379		when.cyt_interval = prof->prof_interval;
380		when.cyt_when = dtrace_gethrtime() + when.cyt_interval;
381	} else {
382		ASSERT(prof->prof_kind == PROF_PROFILE);
383		omni.cyo_online = profile_online;
384		omni.cyo_offline = profile_offline;
385		omni.cyo_arg = prof;
386	}
387
388	if (prof->prof_kind == PROF_TICK) {
389		prof->prof_cyclic = cyclic_add(&hdlr, &when);
390	} else {
391		prof->prof_cyclic = cyclic_add_omni(&omni);
392	}
393	return (0);
394}
395
396/*ARGSUSED*/
397static void
398profile_disable(void *arg, dtrace_id_t id, void *parg)
399{
400	profile_probe_t *prof = parg;
401
402	ASSERT(prof->prof_cyclic != CYCLIC_NONE);
403	ASSERT(MUTEX_HELD(&cpu_lock));
404
405	cyclic_remove(prof->prof_cyclic);
406	prof->prof_cyclic = CYCLIC_NONE;
407}
408
409/*ARGSUSED*/
410static int
411profile_usermode(void *arg, dtrace_id_t id, void *parg)
412{
413	return (CPU->cpu_profile_pc == 0);
414}
415
416static dtrace_pattr_t profile_attr = {
417{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
418{ DTRACE_STABILITY_UNSTABLE, DTRACE_STABILITY_UNSTABLE, DTRACE_CLASS_UNKNOWN },
419{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
420{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
421{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
422};
423
424static dtrace_pops_t profile_pops = {
425	profile_provide,
426	NULL,
427	profile_enable,
428	profile_disable,
429	NULL,
430	NULL,
431	NULL,
432	NULL,
433	profile_usermode,
434	profile_destroy
435};
436
437static int
438profile_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
439{
440	switch (cmd) {
441	case DDI_ATTACH:
442		break;
443	case DDI_RESUME:
444		return (DDI_SUCCESS);
445	default:
446		return (DDI_FAILURE);
447	}
448
449	if (ddi_create_minor_node(devi, "profile", S_IFCHR, 0,
450	    DDI_PSEUDO, NULL) == DDI_FAILURE ||
451	    dtrace_register("profile", &profile_attr,
452	    DTRACE_PRIV_KERNEL | DTRACE_PRIV_USER, NULL,
453	    &profile_pops, NULL, &profile_id) != 0) {
454		ddi_remove_minor_node(devi, NULL);
455		return (DDI_FAILURE);
456	}
457
458	profile_max = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
459	    "profile-max-probes", PROFILE_MAX_DEFAULT);
460
461	ddi_report_dev(devi);
462	profile_devi = devi;
463	return (DDI_SUCCESS);
464}
465
466static int
467profile_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
468{
469	switch (cmd) {
470	case DDI_DETACH:
471		break;
472	case DDI_SUSPEND:
473		return (DDI_SUCCESS);
474	default:
475		return (DDI_FAILURE);
476	}
477
478	if (dtrace_unregister(profile_id) != 0)
479		return (DDI_FAILURE);
480
481	ddi_remove_minor_node(devi, NULL);
482	return (DDI_SUCCESS);
483}
484
485/*ARGSUSED*/
486static int
487profile_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
488{
489	int error;
490
491	switch (infocmd) {
492	case DDI_INFO_DEVT2DEVINFO:
493		*result = (void *)profile_devi;
494		error = DDI_SUCCESS;
495		break;
496	case DDI_INFO_DEVT2INSTANCE:
497		*result = (void *)0;
498		error = DDI_SUCCESS;
499		break;
500	default:
501		error = DDI_FAILURE;
502	}
503	return (error);
504}
505
506/*ARGSUSED*/
507static int
508profile_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
509{
510	return (0);
511}
512
513static struct cb_ops profile_cb_ops = {
514	profile_open,		/* open */
515	nodev,			/* close */
516	nulldev,		/* strategy */
517	nulldev,		/* print */
518	nodev,			/* dump */
519	nodev,			/* read */
520	nodev,			/* write */
521	nodev,			/* ioctl */
522	nodev,			/* devmap */
523	nodev,			/* mmap */
524	nodev,			/* segmap */
525	nochpoll,		/* poll */
526	ddi_prop_op,		/* cb_prop_op */
527	0,			/* streamtab  */
528	D_NEW | D_MP		/* Driver compatibility flag */
529};
530
531static struct dev_ops profile_ops = {
532	DEVO_REV,		/* devo_rev, */
533	0,			/* refcnt  */
534	profile_info,		/* get_dev_info */
535	nulldev,		/* identify */
536	nulldev,		/* probe */
537	profile_attach,		/* attach */
538	profile_detach,		/* detach */
539	nodev,			/* reset */
540	&profile_cb_ops,	/* driver operations */
541	NULL,			/* bus operations */
542	nodev,			/* dev power */
543	ddi_quiesce_not_needed,		/* quiesce */
544};
545
546/*
547 * Module linkage information for the kernel.
548 */
549static struct modldrv modldrv = {
550	&mod_driverops,		/* module type (this is a pseudo driver) */
551	"Profile Interrupt Tracing",	/* name of module */
552	&profile_ops,		/* driver ops */
553};
554
555static struct modlinkage modlinkage = {
556	MODREV_1,
557	(void *)&modldrv,
558	NULL
559};
560
561int
562_init(void)
563{
564	return (mod_install(&modlinkage));
565}
566
567int
568_info(struct modinfo *modinfop)
569{
570	return (mod_info(&modlinkage, modinfop));
571}
572
573int
574_fini(void)
575{
576	return (mod_remove(&modlinkage));
577}
578