xref: /illumos-gate/usr/src/uts/sun4u/sunfire/io/sysctrl_quiesce.c (revision 6f1fa39e3cf1b335f342bbca41590e9d76ab29b7)
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 /*
23  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * This workaround inhibits prom_printf after the cpus are grabbed.
29  * This can be removed when 4154263 is corrected.
30  */
31 #define	Bug_4154263
32 
33 /*
34  * A CPR derivative specifically for sunfire
35  */
36 
37 #include <sys/types.h>
38 #include <sys/systm.h>
39 #include <sys/machparam.h>
40 #include <sys/machsystm.h>
41 #include <sys/ddi.h>
42 #define	SUNDDI_IMPL
43 #include <sys/sunddi.h>
44 #include <sys/time.h>
45 #include <sys/kmem.h>
46 #include <nfs/lm.h>
47 #include <sys/ddi_impldefs.h>
48 #include <sys/obpdefs.h>
49 #include <sys/cmn_err.h>
50 #include <sys/debug.h>
51 #include <sys/errno.h>
52 #include <sys/callb.h>
53 #include <sys/clock.h>
54 #include <sys/x_call.h>
55 #include <sys/cpuvar.h>
56 #include <sys/epm.h>
57 #include <sys/vfs.h>
58 #include <sys/fhc.h>
59 #include <sys/sysctrl.h>
60 #include <sys/promif.h>
61 #include <sys/conf.h>
62 #include <sys/modctl.h>
63 #include <sys/cyclic.h>
64 #include <sys/sunndi.h>
65 #include <sys/machsystm.h>
66 
67 static enum sysctrl_suspend_state {
68 	SYSC_STATE_BEGIN = 0,
69 	SYSC_STATE_USER,
70 	SYSC_STATE_DAEMON,
71 	SYSC_STATE_DRIVER,
72 	SYSC_STATE_FULL } suspend_state;
73 
74 static int	pstate_save;
75 static uint_t	sysctrl_gate[NCPU];
76 int	sysctrl_quiesce_debug = FALSE;
77 static int	sysctrl_skip_kernel_threads = TRUE;
78 
79 /*
80  * sysctrl_skip_user_threads is used to control if user threads should
81  * be suspended.  If sysctrl_skip_user_threads is true, the rest of the
82  * flags are not used; if it is false, sysctrl_check_user_stop_result
83  * will be used to control whether or not we need to check suspend
84  * result, and sysctrl_allow_blocked_threads will be used to control
85  * whether or not we allow suspend to continue if there are blocked
86  * threads.  We allow all combinations of sysctrl_check_user_stop_result
87  * and sysctrl_allow_block_threads, even though it might not make much
88  * sense to not allow block threads when we don't even check stop
89  * result.
90  */
91 static int	sysctrl_skip_user_threads = 0;		/* default to FALSE */
92 static int	sysctrl_check_user_stop_result = 1;	/* default to TRUE */
93 static int	sysctrl_allow_blocked_threads = 1;	/* default to TRUE */
94 
95 static int	sysc_watchdog_suspended;
96 
97 extern int	sysctrl_enable_detach_suspend;
98 static int	sysc_lastval;
99 
100 #define	DEBUGP(p) { if (sysctrl_quiesce_debug) p; }
101 #define	errp	prom_printf
102 
103 #define	SYSC_CPU_LOOP_MSEC	1000
104 
105 static void
106 sysctrl_grab_cpus(void)
107 {
108 	int		i;
109 	cpuset_t	others;
110 	extern cpuset_t	cpu_ready_set;
111 	extern void	sysctrl_freeze(void);
112 	uint64_t	sysc_tick_limit;
113 	uint64_t	sysc_current_tick;
114 	uint64_t	sysc_tick_deadline;
115 
116 	extern u_longlong_t	gettick(void);
117 
118 	for (i = 0; i < NCPU; i++)
119 		sysctrl_gate[i] = 0;
120 
121 	/* tell other cpus to go quiet and wait for continue signal */
122 	others = cpu_ready_set;
123 	CPUSET_DEL(others, CPU->cpu_id);
124 	xt_some(others, (xcfunc_t *)sysctrl_freeze, (uint64_t)sysctrl_gate,
125 	    (uint64_t)(&sysctrl_gate[CPU->cpu_id]));
126 
127 	sysc_tick_limit = ((uint64_t)sys_tick_freq * SYSC_CPU_LOOP_MSEC) / 1000;
128 
129 	/* wait for each cpu to check in */
130 	for (i = 0; i < NCPU; i++) {
131 		if (!CPU_IN_SET(others, i))
132 			continue;
133 
134 		/*
135 		 * Get current tick value and calculate the deadline tick
136 		 */
137 		sysc_current_tick = gettick();
138 		sysc_tick_deadline = sysc_current_tick + sysc_tick_limit;
139 
140 		while (sysctrl_gate[i] == 0) {
141 			/* If in panic, we just return */
142 			if (panicstr)
143 				break;
144 
145 			/* Panic the system if cpu not responsed by deadline */
146 			sysc_current_tick = gettick();
147 			if (sysc_current_tick >= sysc_tick_deadline) {
148 				cmn_err(CE_PANIC, "sysctrl: cpu %d not "
149 				    "responding to quiesce command", i);
150 			}
151 		}
152 	}
153 
154 	/* now even our interrupts are disabled -- really quiet now */
155 	pstate_save = disable_vec_intr();
156 }
157 
158 static void
159 sysctrl_release_cpus(void)
160 {
161 	/* let the other cpus go */
162 	sysctrl_gate[CPU->cpu_id] = 1;
163 
164 	/* restore our interrupts too */
165 	enable_vec_intr(pstate_save);
166 }
167 
168 static void
169 sysctrl_stop_intr(void)
170 {
171 	mutex_enter(&cpu_lock);
172 	kpreempt_disable();
173 	cyclic_suspend();
174 }
175 
176 static void
177 sysctrl_enable_intr(void)
178 {
179 	cyclic_resume();
180 	(void) spl0();
181 	kpreempt_enable();
182 	mutex_exit(&cpu_lock);
183 }
184 
185 static int
186 sysctrl_is_real_device(dev_info_t *dip)
187 {
188 	struct regspec *regbuf;
189 	int length;
190 	int rc;
191 
192 	if (ddi_get_driver(dip) == NULL)
193 		return (FALSE);
194 
195 	if (DEVI(dip)->devi_pm_flags & (PMC_NEEDS_SR|PMC_PARENTAL_SR))
196 		return (TRUE);
197 	if (DEVI(dip)->devi_pm_flags & PMC_NO_SR)
198 		return (FALSE);
199 
200 	/*
201 	 * now the general case
202 	 */
203 	rc = ddi_getlongprop(DDI_DEV_T_ANY, dip, DDI_PROP_DONTPASS, "reg",
204 	    (caddr_t)&regbuf, &length);
205 	ASSERT(rc != DDI_PROP_NO_MEMORY);
206 	if (rc != DDI_PROP_SUCCESS) {
207 		return (FALSE);
208 	} else {
209 		kmem_free(regbuf, length);
210 		return (TRUE);
211 	}
212 }
213 
214 static dev_info_t *failed_driver;
215 static char device_path[MAXPATHLEN];
216 
217 static int
218 sysctrl_suspend_devices(dev_info_t *dip, sysc_cfga_pkt_t *pkt)
219 {
220 	int circ;
221 
222 	ASSERT(dip == NULL || ddi_get_parent(dip) == NULL ||
223 	    DEVI_BUSY_OWNED(ddi_get_parent(dip)));
224 
225 	failed_driver = NULL;
226 	for (; dip != NULL; dip = ddi_get_next_sibling(dip)) {
227 		/*
228 		 * Hold parent busy while walking child list
229 		 */
230 		ndi_devi_enter(dip, &circ);
231 		if (sysctrl_suspend_devices(ddi_get_child(dip), pkt)) {
232 			ndi_devi_exit(dip, circ);
233 			return (ENXIO);
234 		}
235 		ndi_devi_exit(dip, circ);
236 
237 		if (!sysctrl_is_real_device(dip))
238 			continue;
239 
240 		/*
241 		 * Safe to call ddi_pathname() as parent is held busy
242 		 */
243 		(void) ddi_pathname(dip, device_path);
244 		DEBUGP(errp(" suspending device %s\n", device_path));
245 		if (devi_detach(dip, DDI_SUSPEND) != DDI_SUCCESS) {
246 			DEBUGP(errp("  unable to suspend device %s\n",
247 			    device_path));
248 
249 			(void) strncpy(pkt->errbuf, device_path,
250 			    SYSC_OUTPUT_LEN);
251 			SYSC_ERR_SET(pkt, SYSC_ERR_SUSPEND);
252 			ndi_hold_devi(dip);
253 			failed_driver = dip;
254 			return (ENXIO);
255 		}
256 	}
257 
258 	return (DDI_SUCCESS);
259 }
260 
261 static void
262 sysctrl_resume_devices(dev_info_t *start, sysc_cfga_pkt_t *pkt)
263 {
264 	int		circ;
265 	dev_info_t	*dip, *next, *last = NULL;
266 
267 	ASSERT(start == NULL || ddi_get_parent(start) == NULL ||
268 	    DEVI_BUSY_OWNED(ddi_get_parent(start)));
269 
270 	/* attach in reverse device tree order */
271 	while (last != start) {
272 		dip = start;
273 		next = ddi_get_next_sibling(dip);
274 		while (next != last && dip != failed_driver) {
275 			dip = next;
276 			next = ddi_get_next_sibling(dip);
277 		}
278 		if (dip == failed_driver) {
279 			failed_driver = NULL;
280 			ndi_rele_devi(dip);
281 		} else if (sysctrl_is_real_device(dip) &&
282 		    failed_driver == NULL) {
283 			/*
284 			 * Parent dip is held busy, so ddi_pathname() can
285 			 * be safely called.
286 			 */
287 			(void) ddi_pathname(dip, device_path);
288 			DEBUGP(errp(" resuming device %s\n", device_path));
289 			if (devi_attach(dip, DDI_RESUME) != DDI_SUCCESS) {
290 				/*
291 				 * XXX - if in the future we decide not to
292 				 * panic the system, we need to set the error
293 				 * SYSC_ERR_RESUME here and also change the
294 				 * cfgadm platform library.
295 				 */
296 				cmn_err(CE_PANIC, "Unable to resume device %s",
297 				    device_path);
298 			}
299 		}
300 		ndi_devi_enter(dip, &circ);
301 		sysctrl_resume_devices(ddi_get_child(dip), pkt);
302 		ndi_devi_exit(dip, circ);
303 
304 		last = dip;
305 	}
306 }
307 
308 /*
309  * True if thread is virtually stopped.  Similar to CPR_VSTOPPED
310  * but from DR point of view.  These user threads are waiting in
311  * the kernel.  Once they complete in the kernel, they will process
312  * the stop signal and stop.
313  */
314 #define	SYSCTRL_VSTOPPED(t)		\
315 	((t)->t_state == TS_SLEEP &&	\
316 	(t)->t_wchan != NULL &&		\
317 	(t)->t_astflag &&		\
318 	((t)->t_proc_flag & TP_CHKPT))
319 
320 static int
321 sysctrl_stop_user_threads(sysc_cfga_pkt_t *pkt)
322 {
323 	int		count;
324 	char		cache_psargs[PSARGSZ];
325 	kthread_id_t	cache_tp;
326 	uint_t		cache_t_state;
327 	int		bailout;
328 	pid_t		pid;
329 
330 	extern void add_one_utstop();
331 	extern void utstop_timedwait(clock_t);
332 	extern void utstop_init(void);
333 
334 #define	SYSCTRL_UTSTOP_RETRY	4
335 #define	SYSCTRL_UTSTOP_WAIT	hz
336 
337 	if (sysctrl_skip_user_threads)
338 		return (DDI_SUCCESS);
339 
340 	utstop_init();
341 
342 	/* we need to try a few times to get past fork, etc. */
343 	for (count = 0; count < SYSCTRL_UTSTOP_RETRY; count++) {
344 		kthread_id_t tp;
345 
346 		/* walk the entire threadlist */
347 		mutex_enter(&pidlock);
348 		for (tp = curthread->t_next; tp != curthread; tp = tp->t_next) {
349 			proc_t *p = ttoproc(tp);
350 
351 			/* handle kernel threads separately */
352 			if (p->p_as == &kas || p->p_stat == SZOMB)
353 				continue;
354 
355 			mutex_enter(&p->p_lock);
356 			thread_lock(tp);
357 
358 			if (tp->t_state == TS_STOPPED) {
359 				/* add another reason to stop this thread */
360 				tp->t_schedflag &= ~TS_RESUME;
361 			} else {
362 				tp->t_proc_flag |= TP_CHKPT;
363 
364 				thread_unlock(tp);
365 				mutex_exit(&p->p_lock);
366 				add_one_utstop();
367 				mutex_enter(&p->p_lock);
368 				thread_lock(tp);
369 
370 				aston(tp);
371 
372 				if (ISWAKEABLE(tp) || ISWAITING(tp)) {
373 					setrun_locked(tp);
374 				}
375 
376 			}
377 
378 			/* grab thread if needed */
379 			if (tp->t_state == TS_ONPROC && tp->t_cpu != CPU)
380 				poke_cpu(tp->t_cpu->cpu_id);
381 
382 
383 			thread_unlock(tp);
384 			mutex_exit(&p->p_lock);
385 		}
386 		mutex_exit(&pidlock);
387 
388 
389 		/* let everything catch up */
390 		utstop_timedwait(count * count * SYSCTRL_UTSTOP_WAIT);
391 
392 
393 		/* now, walk the threadlist again to see if we are done */
394 		mutex_enter(&pidlock);
395 		for (tp = curthread->t_next, bailout = 0;
396 		    bailout == 0 && tp != curthread; tp = tp->t_next) {
397 			proc_t *p = ttoproc(tp);
398 
399 			/* handle kernel threads separately */
400 			if (p->p_as == &kas || p->p_stat == SZOMB)
401 				continue;
402 
403 			/*
404 			 * If this thread didn't stop, and we don't allow
405 			 * unstopped blocked threads, bail.
406 			 */
407 			/* did this thread stop? */
408 			thread_lock(tp);
409 			if (!CPR_ISTOPPED(tp) &&
410 			    !(sysctrl_allow_blocked_threads &&
411 			    SYSCTRL_VSTOPPED(tp))) {
412 
413 				/* nope, cache the details for later */
414 				bcopy(p->p_user.u_psargs, cache_psargs,
415 				    sizeof (cache_psargs));
416 				cache_tp = tp;
417 				cache_t_state = tp->t_state;
418 				bailout = 1;
419 				pid = p->p_pidp->pid_id;
420 			}
421 			thread_unlock(tp);
422 		}
423 		mutex_exit(&pidlock);
424 
425 		/* were all the threads stopped? */
426 		if (!bailout)
427 			break;
428 	}
429 
430 	/* were we unable to stop all threads after a few tries? */
431 	if (bailout) {
432 		(void) sprintf(pkt->errbuf, "process: %s id: %d state: %x"
433 		    " thread descriptor: %p", cache_psargs, (int)pid,
434 		    cache_t_state, (void *)cache_tp);
435 
436 		SYSC_ERR_SET(pkt, SYSC_ERR_UTHREAD);
437 
438 		return (ESRCH);
439 	}
440 
441 	return (DDI_SUCCESS);
442 }
443 
444 static int
445 sysctrl_stop_kernel_threads(sysc_cfga_pkt_t *pkt)
446 {
447 	caddr_t		name;
448 	kthread_id_t	tp;
449 
450 	if (sysctrl_skip_kernel_threads) {
451 		return (DDI_SUCCESS);
452 	}
453 
454 	/*
455 	 * Note: we unlock the table in resume.
456 	 * We only need to lock the callback table if we are actually
457 	 * suspending kernel threads.
458 	 */
459 	callb_lock_table();
460 	if ((name = callb_execute_class(CB_CL_CPR_DAEMON,
461 	    CB_CODE_CPR_CHKPT)) != (caddr_t)NULL) {
462 
463 		(void) strncpy(pkt->errbuf, name, SYSC_OUTPUT_LEN);
464 		SYSC_ERR_SET(pkt, SYSC_ERR_KTHREAD);
465 		return (EBUSY);
466 	}
467 
468 	/*
469 	 * Verify that all threads are accounted for
470 	 */
471 	mutex_enter(&pidlock);
472 	for (tp = curthread->t_next; tp != curthread; tp = tp->t_next) {
473 		proc_t	*p = ttoproc(tp);
474 
475 		if (p->p_as != &kas)
476 			continue;
477 
478 		if (tp->t_flag & T_INTR_THREAD)
479 			continue;
480 
481 		if (!callb_is_stopped(tp, &name)) {
482 			mutex_exit(&pidlock);
483 			(void) strncpy(pkt->errbuf, name, SYSC_OUTPUT_LEN);
484 			SYSC_ERR_SET(pkt, SYSC_ERR_KTHREAD);
485 			return (EBUSY);
486 		}
487 	}
488 
489 	mutex_exit(&pidlock);
490 	return (DDI_SUCCESS);
491 }
492 
493 static void
494 sysctrl_start_user_threads(void)
495 {
496 	kthread_id_t tp;
497 
498 	mutex_enter(&pidlock);
499 
500 	/* walk all threads and release them */
501 	for (tp = curthread->t_next; tp != curthread; tp = tp->t_next) {
502 		proc_t *p = ttoproc(tp);
503 
504 		/* skip kernel threads */
505 		if (ttoproc(tp)->p_as == &kas)
506 			continue;
507 
508 		mutex_enter(&p->p_lock);
509 		tp->t_proc_flag &= ~TP_CHKPT;
510 		mutex_exit(&p->p_lock);
511 
512 		thread_lock(tp);
513 		if (CPR_ISTOPPED(tp)) {
514 			/* back on the runq */
515 			tp->t_schedflag |= TS_RESUME;
516 			setrun_locked(tp);
517 		}
518 		thread_unlock(tp);
519 	}
520 
521 	mutex_exit(&pidlock);
522 }
523 
524 static void
525 sysctrl_signal_user(int sig)
526 {
527 	struct proc *p;
528 
529 	mutex_enter(&pidlock);
530 
531 	for (p = practive; p != NULL; p = p->p_next) {
532 		/* only user threads */
533 		if (p->p_exec == NULL || p->p_stat == SZOMB ||
534 		    p == proc_init || p == ttoproc(curthread))
535 			continue;
536 
537 		mutex_enter(&p->p_lock);
538 		sigtoproc(p, NULL, sig);
539 		mutex_exit(&p->p_lock);
540 	}
541 
542 	mutex_exit(&pidlock);
543 
544 	/* add a bit of delay */
545 	delay(hz);
546 }
547 
548 void
549 sysctrl_resume(sysc_cfga_pkt_t *pkt)
550 {
551 #ifndef Bug_4154263
552 	DEBUGP(errp("resume system...\n"));
553 #endif
554 	switch (suspend_state) {
555 	case SYSC_STATE_FULL:
556 		/*
557 		 * release all the other cpus
558 		 */
559 #ifndef	Bug_4154263
560 		DEBUGP(errp("release cpus..."));
561 #endif
562 		/*
563 		 * Prevent false alarm in tod_validate() due to tod
564 		 * value change between suspend and resume
565 		 */
566 		mutex_enter(&tod_lock);
567 		tod_status_set(TOD_DR_RESUME_DONE);
568 		mutex_exit(&tod_lock);
569 
570 		sysctrl_release_cpus();
571 		DEBUGP(errp("cpus resumed...\n"));
572 
573 		/*
574 		 * If we suspended hw watchdog at suspend,
575 		 * re-enable it now.
576 		 */
577 		if (sysc_watchdog_suspended) {
578 			mutex_enter(&tod_lock);
579 			(void) tod_ops.tod_set_watchdog_timer(
580 			    watchdog_timeout_seconds);
581 			mutex_exit(&tod_lock);
582 		}
583 
584 		/*
585 		 * resume callout
586 		 */
587 		(void) callb_execute_class(CB_CL_CPR_RPC, CB_CODE_CPR_RESUME);
588 		(void) callb_execute_class(CB_CL_CPR_CALLOUT,
589 		    CB_CODE_CPR_RESUME);
590 		sysctrl_enable_intr();
591 		/* FALLTHROUGH */
592 
593 	case SYSC_STATE_DRIVER:
594 		/*
595 		 * resume drivers
596 		 */
597 		DEBUGP(errp("resume drivers..."));
598 		sysctrl_resume_devices(ddi_root_node(), pkt);
599 		DEBUGP(errp("done\n"));
600 
601 		/*
602 		 * resume the lock manager
603 		 */
604 		lm_cprresume();
605 
606 		/* FALLTHROUGH */
607 
608 	case SYSC_STATE_DAEMON:
609 		/*
610 		 * resume kernel daemons
611 		 */
612 		if (!sysctrl_skip_kernel_threads) {
613 			DEBUGP(errp("starting kernel daemons..."));
614 			(void) callb_execute_class(CB_CL_CPR_DAEMON,
615 			    CB_CODE_CPR_RESUME);
616 			callb_unlock_table();
617 		}
618 		DEBUGP(errp("done\n"));
619 
620 		/* FALLTHROUGH */
621 
622 	case SYSC_STATE_USER:
623 		/*
624 		 * finally, resume user threads
625 		 */
626 		if (!sysctrl_skip_user_threads) {
627 			DEBUGP(errp("starting user threads..."));
628 			sysctrl_start_user_threads();
629 			DEBUGP(errp("done\n"));
630 		}
631 		/* FALLTHROUGH */
632 
633 	case SYSC_STATE_BEGIN:
634 	default:
635 		/*
636 		 * let those who care know that we've just resumed
637 		 */
638 		DEBUGP(errp("sending SIGTHAW..."));
639 		sysctrl_signal_user(SIGTHAW);
640 		DEBUGP(errp("done\n"));
641 		break;
642 	}
643 
644 	/* Restore sysctrl detach/suspend to its original value */
645 	sysctrl_enable_detach_suspend = sysc_lastval;
646 
647 	DEBUGP(errp("system state restored\n"));
648 }
649 
650 void
651 sysctrl_suspend_prepare(void)
652 {
653 	/*
654 	 * We use a function, lm_cprsuspend(), in the suspend flow that
655 	 * is redirected to a module through the modstubs mechanism.
656 	 * If the module is currently not loaded, modstubs attempts
657 	 * the modload. The context this happens in below causes the
658 	 * module load to block forever, so this function must be called
659 	 * in the normal system call context ahead of time.
660 	 */
661 	(void) modload("misc", "klmmod");
662 }
663 
664 int
665 sysctrl_suspend(sysc_cfga_pkt_t *pkt)
666 {
667 	int rc = DDI_SUCCESS;
668 
669 	/* enable sysctrl detach/suspend function */
670 	sysc_lastval = sysctrl_enable_detach_suspend;
671 	sysctrl_enable_detach_suspend = 1;
672 
673 	/*
674 	 * first, stop all user threads
675 	 */
676 	DEBUGP(errp("\nstopping user threads..."));
677 	suspend_state = SYSC_STATE_USER;
678 	if (((rc = sysctrl_stop_user_threads(pkt)) != DDI_SUCCESS) &&
679 	    sysctrl_check_user_stop_result) {
680 		sysctrl_resume(pkt);
681 		return (rc);
682 	}
683 	DEBUGP(errp("done\n"));
684 
685 	/*
686 	 * now stop daemon activities
687 	 */
688 	DEBUGP(errp("stopping kernel daemons..."));
689 	suspend_state = SYSC_STATE_DAEMON;
690 	if (rc = sysctrl_stop_kernel_threads(pkt)) {
691 		sysctrl_resume(pkt);
692 		return (rc);
693 	}
694 	DEBUGP(errp("done\n"));
695 
696 	/*
697 	 * This sync swap out all user pages
698 	 */
699 	vfs_sync(SYNC_ALL);
700 
701 	/*
702 	 * special treatment for lock manager
703 	 */
704 	lm_cprsuspend();
705 
706 	/*
707 	 * sync the file system in case we never make it back
708 	 */
709 	sync();
710 
711 	/*
712 	 * now suspend drivers
713 	 */
714 	DEBUGP(errp("suspending drivers..."));
715 	suspend_state = SYSC_STATE_DRIVER;
716 	if (rc = sysctrl_suspend_devices(ddi_root_node(), pkt)) {
717 		sysctrl_resume(pkt);
718 		return (rc);
719 	}
720 	DEBUGP(errp("done\n"));
721 
722 	/*
723 	 * handle the callout table
724 	 */
725 	sysctrl_stop_intr();
726 
727 	(void) callb_execute_class(CB_CL_CPR_CALLOUT, CB_CODE_CPR_CHKPT);
728 
729 	/*
730 	 * if watchdog was activated, disable it
731 	 */
732 	if (watchdog_activated) {
733 		mutex_enter(&tod_lock);
734 		(void) tod_ops.tod_clear_watchdog_timer();
735 		mutex_exit(&tod_lock);
736 		sysc_watchdog_suspended = 1;
737 	} else {
738 		sysc_watchdog_suspended = 0;
739 	}
740 
741 	/*
742 	 * finally, grab all cpus
743 	 */
744 	DEBUGP(errp("freezing all cpus...\n"));
745 	suspend_state = SYSC_STATE_FULL;
746 	sysctrl_grab_cpus();
747 #ifndef	Bug_4154263
748 	DEBUGP(errp("done\n"));
749 
750 	DEBUGP(errp("system is quiesced\n"));
751 #endif
752 
753 	return (rc);
754 }
755