xref: /titanic_50/usr/src/uts/sun4/os/mp_startup.c (revision b5a2d8455dfa3190fc977c4bec53e91c99012767)
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 2009 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #include <sys/sysmacros.h>
28 #include <sys/prom_plat.h>
29 #include <sys/prom_debug.h>
30 #include <vm/hat_sfmmu.h>
31 #include <vm/seg_kp.h>
32 #include <vm/seg_kmem.h>
33 #include <sys/machsystm.h>
34 #include <sys/callb.h>
35 #include <sys/cpu_module.h>
36 #include <sys/pg.h>
37 #include <sys/cmt.h>
38 #include <sys/dtrace.h>
39 #include <sys/reboot.h>
40 #include <sys/kdi.h>
41 #include <sys/traptrace.h>
42 #ifdef TRAPTRACE
43 #include <sys/bootconf.h>
44 #endif /* TRAPTRACE */
45 #include <sys/cpu_sgnblk_defs.h>
46 
47 extern int cpu_intrq_setup(struct cpu *);
48 extern void cpu_intrq_cleanup(struct cpu *);
49 extern void cpu_intrq_register(struct cpu *);
50 
51 struct cpu	*cpus;	/* pointer to other cpus; dynamically allocate */
52 struct cpu	*cpu[NCPU];	/* pointers to all CPUs */
53 uint64_t	cpu_pa[NCPU];	/* pointers to all CPUs in PA */
54 cpu_core_t	cpu_core[NCPU];	/* cpu_core structures */
55 
56 #ifdef TRAPTRACE
57 caddr_t	ttrace_buf;	/* kmem64 traptrace for all cpus except 0 */
58 #endif /* TRAPTRACE */
59 
60 /* bit mask of cpus ready for x-calls, protected by cpu_lock */
61 cpuset_t cpu_ready_set;
62 
63 /* bit mask used to communicate with cpus during bringup */
64 static cpuset_t proxy_ready_set;
65 
66 static void	slave_startup(void);
67 
68 /*
69  * Defined in $KARCH/os/mach_mp_startup.c
70  */
71 #pragma weak init_cpu_info
72 
73 /*
74  * Amount of time (in milliseconds) we should wait before giving up on CPU
75  * initialization and assuming that the CPU we're trying to wake up is dead
76  * or out of control.
77  */
78 #define	CPU_WAKEUP_GRACE_MSEC 1000
79 
80 #ifdef	TRAPTRACE
81 /*
82  * This function sets traptrace buffers for all cpus
83  * other than boot cpu.
84  */
85 size_t
86 calc_traptrace_sz(void)
87 {
88 	return (TRAP_TSIZE * (max_ncpus - 1));
89 }
90 #endif	/* TRAPTRACE */
91 
92 
93 /*
94  * common slave cpu initialization code
95  */
96 void
97 common_startup_init(cpu_t *cp, int cpuid)
98 {
99 	kthread_id_t tp;
100 	sfmmu_t *sfmmup;
101 	caddr_t	sp;
102 
103 	/*
104 	 * Allocate and initialize the startup thread for this CPU.
105 	 */
106 	tp = thread_create(NULL, 0, slave_startup, NULL, 0, &p0,
107 	    TS_STOPPED, maxclsyspri);
108 
109 	/*
110 	 * Set state to TS_ONPROC since this thread will start running
111 	 * as soon as the CPU comes online.
112 	 *
113 	 * All the other fields of the thread structure are setup by
114 	 * thread_create().
115 	 */
116 	THREAD_ONPROC(tp, cp);
117 	tp->t_preempt = 1;
118 	tp->t_bound_cpu = cp;
119 	tp->t_affinitycnt = 1;
120 	tp->t_cpu = cp;
121 	tp->t_disp_queue = cp->cpu_disp;
122 
123 	sfmmup = astosfmmu(&kas);
124 	CPUSET_ADD(sfmmup->sfmmu_cpusran, cpuid);
125 
126 	/*
127 	 * Setup thread to start in slave_startup.
128 	 */
129 	sp = tp->t_stk;
130 	tp->t_pc = (uintptr_t)slave_startup - 8;
131 	tp->t_sp = (uintptr_t)((struct rwindow *)sp - 1) - STACK_BIAS;
132 
133 	cp->cpu_id = cpuid;
134 	cp->cpu_self = cp;
135 	cp->cpu_thread = tp;
136 	cp->cpu_lwp = NULL;
137 	cp->cpu_dispthread = tp;
138 	cp->cpu_dispatch_pri = DISP_PRIO(tp);
139 	cp->cpu_startup_thread = tp;
140 }
141 
142 /*
143  * parametric flag setting functions.  these routines set the cpu
144  * state just prior to releasing the slave cpu.
145  */
146 void
147 cold_flag_set(int cpuid)
148 {
149 	cpu_t *cp;
150 
151 	ASSERT(MUTEX_HELD(&cpu_lock));
152 
153 	cp = cpu[cpuid];
154 	cp->cpu_flags |= CPU_RUNNING | CPU_ENABLE | CPU_EXISTS;
155 	cpu_add_active(cp);
156 	/*
157 	 * Add CPU_READY after the cpu_add_active() call
158 	 * to avoid pausing cp.
159 	 */
160 	cp->cpu_flags |= CPU_READY;		/* ready */
161 	cpu_set_state(cp);
162 }
163 
164 static void
165 warm_flag_set(int cpuid)
166 {
167 	cpu_t *cp;
168 
169 	ASSERT(MUTEX_HELD(&cpu_lock));
170 
171 	/*
172 	 * warm start activates cpus into the OFFLINE state
173 	 */
174 	cp = cpu[cpuid];
175 	cp->cpu_flags |= CPU_RUNNING | CPU_READY | CPU_EXISTS
176 	    | CPU_OFFLINE | CPU_QUIESCED;
177 	cpu_set_state(cp);
178 }
179 
180 /*
181  * Internal cpu startup sequencer
182  * The sequence is as follows:
183  *
184  * MASTER	SLAVE
185  * -------	----------
186  * assume the kernel data is initialized
187  * clear the proxy bit
188  * start the slave cpu
189  * wait for the slave cpu to set the proxy
190  *
191  *		the slave runs slave_startup and then sets the proxy
192  *		the slave waits for the master to add slave to the ready set
193  *
194  * the master finishes the initialization and
195  * adds the slave to the ready set
196  *
197  *		the slave exits the startup thread and is running
198  */
199 void
200 start_cpu(int cpuid, void(*flag_func)(int))
201 {
202 	extern void cpu_startup(int);
203 	int timout;
204 
205 	ASSERT(MUTEX_HELD(&cpu_lock));
206 
207 	/*
208 	 * Before we begin the dance, tell DTrace that we're about to start
209 	 * a CPU.
210 	 */
211 	if (dtrace_cpustart_init != NULL)
212 		(*dtrace_cpustart_init)();
213 
214 	/* start the slave cpu */
215 	CPUSET_DEL(proxy_ready_set, cpuid);
216 	if (prom_test("SUNW,start-cpu-by-cpuid") == 0) {
217 		(void) prom_startcpu_bycpuid(cpuid, (caddr_t)&cpu_startup,
218 		    cpuid);
219 	} else {
220 		/* "by-cpuid" interface didn't exist.  Do it the old way */
221 		pnode_t nodeid = cpunodes[cpuid].nodeid;
222 
223 		ASSERT(nodeid != (pnode_t)0);
224 		(void) prom_startcpu(nodeid, (caddr_t)&cpu_startup, cpuid);
225 	}
226 
227 	/* wait for the slave cpu to check in. */
228 	for (timout = CPU_WAKEUP_GRACE_MSEC; timout; timout--) {
229 		if (CPU_IN_SET(proxy_ready_set, cpuid))
230 			break;
231 		DELAY(1000);
232 	}
233 	if (timout == 0) {
234 		panic("cpu%d failed to start (2)", cpuid);
235 	}
236 
237 	/*
238 	 * The slave has started; we can tell DTrace that it's safe again.
239 	 */
240 	if (dtrace_cpustart_fini != NULL)
241 		(*dtrace_cpustart_fini)();
242 
243 	/* run the master side of stick synchronization for the slave cpu */
244 	sticksync_master();
245 
246 	/*
247 	 * deal with the cpu flags in a phase-specific manner
248 	 * for various reasons, this needs to run after the slave
249 	 * is checked in but before the slave is released.
250 	 */
251 	(*flag_func)(cpuid);
252 
253 	/* release the slave */
254 	CPUSET_ADD(cpu_ready_set, cpuid);
255 }
256 
257 #ifdef TRAPTRACE
258 int trap_tr0_inuse = 1;	/* it is always used on the boot cpu */
259 int trap_trace_inuse[NCPU];
260 #endif /* TRAPTRACE */
261 
262 #define	cpu_next_free	cpu_prev
263 
264 /*
265  * Routine to set up a CPU to prepare for starting it up.
266  */
267 int
268 setup_cpu_common(int cpuid)
269 {
270 	struct cpu *cp = NULL;
271 	kthread_id_t tp;
272 #ifdef TRAPTRACE
273 	int tt_index;
274 	TRAP_TRACE_CTL	*ctlp;
275 	caddr_t	newbuf;
276 #endif /* TRAPTRACE */
277 
278 	extern void idle();
279 	int	rval;
280 
281 	ASSERT(MUTEX_HELD(&cpu_lock));
282 	ASSERT(cpu[cpuid] == NULL);
283 
284 	ASSERT(ncpus <= max_ncpus);
285 
286 #ifdef TRAPTRACE
287 	/*
288 	 * allocate a traptrace buffer for this CPU.
289 	 */
290 	ctlp = &trap_trace_ctl[cpuid];
291 	if (!trap_tr0_inuse) {
292 		trap_tr0_inuse = 1;
293 		newbuf = trap_tr0;
294 		tt_index = -1;
295 	} else {
296 		for (tt_index = 0; tt_index < (max_ncpus-1); tt_index++)
297 			if (!trap_trace_inuse[tt_index])
298 				break;
299 		ASSERT(tt_index < max_ncpus - 1);
300 		trap_trace_inuse[tt_index] = 1;
301 		newbuf = (caddr_t)(ttrace_buf + (tt_index * TRAP_TSIZE));
302 	}
303 	ctlp->d.vaddr_base = newbuf;
304 	ctlp->d.offset = ctlp->d.last_offset = 0;
305 	ctlp->d.limit = trap_trace_bufsize;
306 	ctlp->d.paddr_base = va_to_pa(newbuf);
307 	ASSERT(ctlp->d.paddr_base != (uint64_t)-1);
308 #endif /* TRAPTRACE */
309 	/*
310 	 * initialize hv traptrace buffer for this CPU
311 	 */
312 	mach_htraptrace_setup(cpuid);
313 
314 	/*
315 	 * Obtain pointer to the appropriate cpu structure.
316 	 */
317 	if (cpu0.cpu_flags == 0) {
318 		cp = &cpu0;
319 	} else {
320 		/*
321 		 *  When dynamically allocating cpu structs,
322 		 *  cpus is used as a pointer to a list of freed
323 		 *  cpu structs.
324 		 */
325 		if (cpus) {
326 			/* grab the first cpu struct on the free list */
327 			cp = cpus;
328 			if (cp->cpu_next_free)
329 				cpus = cp->cpu_next_free;
330 			else
331 				cpus = NULL;
332 		}
333 	}
334 
335 	if (cp == NULL)
336 		cp = vmem_xalloc(static_alloc_arena, CPU_ALLOC_SIZE,
337 		    CPU_ALLOC_SIZE, 0, 0, NULL, NULL, VM_SLEEP);
338 
339 	bzero(cp, sizeof (*cp));
340 
341 	cp->cpu_id = cpuid;
342 	cp->cpu_self = cp;
343 
344 	/*
345 	 * Initialize ptl1_panic stack
346 	 */
347 	ptl1_init_cpu(cp);
348 
349 	/*
350 	 * Initialize the dispatcher for this CPU.
351 	 */
352 	disp_cpu_init(cp);
353 
354 	/*
355 	 * Bootstrap the CPU's PG data
356 	 */
357 	pg_cpu_bootstrap(cp);
358 
359 	cpu_vm_data_init(cp);
360 
361 	/*
362 	 * Now, initialize per-CPU idle thread for this CPU.
363 	 */
364 	tp = thread_create(NULL, 0, idle, NULL, 0, &p0, TS_ONPROC, -1);
365 
366 	cp->cpu_idle_thread = tp;
367 
368 	tp->t_preempt = 1;
369 	tp->t_bound_cpu = cp;
370 	tp->t_affinitycnt = 1;
371 	tp->t_cpu = cp;
372 	tp->t_disp_queue = cp->cpu_disp;
373 
374 	/*
375 	 * Registering a thread in the callback table is usually
376 	 * done in the initialization code of the thread. In this
377 	 * case, we do it right after thread creation to avoid
378 	 * blocking idle thread while registering itself. It also
379 	 * avoids the possibility of reregistration in case a CPU
380 	 * restarts its idle thread.
381 	 */
382 	CALLB_CPR_INIT_SAFE(tp, "idle");
383 
384 	init_cpu_info(cp);
385 
386 	/*
387 	 * Initialize the interrupt threads for this CPU
388 	 */
389 	cpu_intr_alloc(cp, NINTR_THREADS);
390 
391 	/*
392 	 * Add CPU to list of available CPUs.
393 	 * It'll be on the active list after it is started.
394 	 */
395 	cpu_add_unit(cp);
396 
397 	/*
398 	 * Allocate and init cpu module private data structures,
399 	 * including scrubber.
400 	 */
401 	cpu_init_private(cp);
402 	populate_idstr(cp);
403 
404 	/*
405 	 * Initialize the CPUs physical ID cache, and processor groups
406 	 */
407 	pghw_physid_create(cp);
408 	pg_cpu_init(cp);
409 
410 	if ((rval = cpu_intrq_setup(cp)) != 0) {
411 		return (rval);
412 	}
413 
414 	/*
415 	 * Initialize MMU context domain information.
416 	 */
417 	sfmmu_cpu_init(cp);
418 
419 	return (0);
420 }
421 
422 /*
423  * Routine to clean up a CPU after shutting it down.
424  */
425 int
426 cleanup_cpu_common(int cpuid)
427 {
428 	struct cpu *cp;
429 #ifdef TRAPTRACE
430 	int i;
431 	TRAP_TRACE_CTL	*ctlp;
432 	caddr_t	newbuf;
433 #endif /* TRAPTRACE */
434 
435 	ASSERT(MUTEX_HELD(&cpu_lock));
436 	ASSERT(cpu[cpuid] != NULL);
437 
438 	cp = cpu[cpuid];
439 
440 	/* Free cpu module private data structures, including scrubber. */
441 	cpu_uninit_private(cp);
442 
443 	/* Free cpu ID string and brand string. */
444 	if (cp->cpu_idstr)
445 		kmem_free(cp->cpu_idstr, strlen(cp->cpu_idstr) + 1);
446 	if (cp->cpu_brandstr)
447 		kmem_free(cp->cpu_brandstr, strlen(cp->cpu_brandstr) + 1);
448 
449 	cpu_vm_data_destroy(cp);
450 
451 	/*
452 	 * Remove CPU from list of available CPUs.
453 	 */
454 	cpu_del_unit(cpuid);
455 
456 	/*
457 	 * Clean any machine specific interrupt states.
458 	 */
459 	cpu_intrq_cleanup(cp);
460 
461 	/*
462 	 * At this point, the only threads bound to this CPU should be
463 	 * special per-cpu threads: it's idle thread, it's pause thread,
464 	 * and it's interrupt threads.  Clean these up.
465 	 */
466 	cpu_destroy_bound_threads(cp);
467 
468 	/*
469 	 * Free the interrupt stack.
470 	 */
471 	segkp_release(segkp, cp->cpu_intr_stack);
472 
473 	/*
474 	 * Free hv traptrace buffer for this CPU.
475 	 */
476 	mach_htraptrace_cleanup(cpuid);
477 #ifdef TRAPTRACE
478 	/*
479 	 * Free the traptrace buffer for this CPU.
480 	 */
481 	ctlp = &trap_trace_ctl[cpuid];
482 	newbuf = ctlp->d.vaddr_base;
483 	i = (newbuf - ttrace_buf) / (TRAP_TSIZE);
484 	if (((newbuf - ttrace_buf) % (TRAP_TSIZE) == 0) &&
485 	    ((i >= 0) && (i < (max_ncpus-1)))) {
486 		/*
487 		 * This CPU got it's trap trace buffer from the
488 		 * boot-alloc'd bunch of them.
489 		 */
490 		trap_trace_inuse[i] = 0;
491 		bzero(newbuf, (TRAP_TSIZE));
492 	} else if (newbuf == trap_tr0) {
493 		trap_tr0_inuse = 0;
494 		bzero(trap_tr0, (TRAP_TSIZE));
495 	} else {
496 		cmn_err(CE_WARN, "failed to free trap trace buffer from cpu%d",
497 		    cpuid);
498 	}
499 	bzero(ctlp, sizeof (*ctlp));
500 #endif /* TRAPTRACE */
501 
502 	/*
503 	 * There is a race condition with mutex_vector_enter() which
504 	 * caches a cpu pointer. The race is detected by checking cpu_next.
505 	 */
506 	disp_cpu_fini(cp);
507 	cpu_pa[cpuid] = 0;
508 	if (CPU_MMU_CTXP(cp))
509 		sfmmu_cpu_cleanup(cp);
510 	bzero(cp, sizeof (*cp));
511 
512 	/*
513 	 * Place the freed cpu structure on the list of freed cpus.
514 	 */
515 	if (cp != &cpu0) {
516 		if (cpus) {
517 			cp->cpu_next_free = cpus;
518 			cpus = cp;
519 		}
520 		else
521 			cpus = cp;
522 	}
523 
524 	return (0);
525 }
526 
527 /*
528  * This routine is used to start a previously powered off processor.
529  * Note that restarted cpus are initialized into the offline state.
530  */
531 void
532 restart_other_cpu(int cpuid)
533 {
534 	struct cpu *cp;
535 	kthread_id_t tp;
536 	caddr_t	sp;
537 	extern void idle();
538 
539 	ASSERT(MUTEX_HELD(&cpu_lock));
540 	ASSERT(cpuid < NCPU && cpu[cpuid] != NULL);
541 
542 	/*
543 	 * Obtain pointer to the appropriate cpu structure.
544 	 */
545 	cp = cpu[cpuid];
546 
547 	common_startup_init(cp, cpuid);
548 
549 	/*
550 	 * idle thread t_lock is held when the idle thread is suspended.
551 	 * Manually unlock the t_lock of idle loop so that we can resume
552 	 * the suspended idle thread.
553 	 * Also adjust the PC of idle thread for re-retry.
554 	 */
555 	cp->cpu_intr_actv = 0;	/* clear the value from previous life */
556 	cp->cpu_m.mutex_ready = 0; /* we are not ready yet */
557 	lock_clear(&cp->cpu_idle_thread->t_lock);
558 	tp = cp->cpu_idle_thread;
559 
560 	sp = tp->t_stk;
561 	tp->t_sp = (uintptr_t)((struct rwindow *)sp - 1) - STACK_BIAS;
562 	tp->t_pc = (uintptr_t)idle - 8;
563 
564 	/*
565 	 * restart the cpu now
566 	 */
567 	promsafe_pause_cpus();
568 	start_cpu(cpuid, warm_flag_set);
569 	start_cpus();
570 
571 	/* call cmn_err outside pause_cpus/start_cpus to avoid deadlock */
572 	cmn_err(CE_CONT, "!cpu%d initialization complete - restarted\n",
573 	    cpuid);
574 }
575 
576 /*
577  * Startup function executed on 'other' CPUs.  This is the first
578  * C function after cpu_start sets up the cpu registers.
579  */
580 static void
581 slave_startup(void)
582 {
583 	struct cpu	*cp = CPU;
584 	ushort_t	original_flags = cp->cpu_flags;
585 
586 	mach_htraptrace_configure(cp->cpu_id);
587 	cpu_intrq_register(CPU);
588 	cp->cpu_m.mutex_ready = 1;
589 	cp->cpu_m.poke_cpu_outstanding = B_FALSE;
590 
591 	/* acknowledge that we are done with initialization */
592 	CPUSET_ADD(proxy_ready_set, cp->cpu_id);
593 
594 	/* synchronize STICK */
595 	sticksync_slave();
596 
597 	if (boothowto & RB_DEBUG)
598 		kdi_dvec_cpu_init(cp);
599 
600 	/*
601 	 * the slave will wait here forever -- assuming that the master
602 	 * will get back to us.  if it doesn't we've got bigger problems
603 	 * than a master not replying to this slave.
604 	 * the small delay improves the slave's responsiveness to the
605 	 * master's ack and decreases the time window between master and
606 	 * slave operations.
607 	 */
608 	while (!CPU_IN_SET(cpu_ready_set, cp->cpu_id))
609 		DELAY(1);
610 
611 	/* enable interrupts */
612 	(void) spl0();
613 
614 	/*
615 	 * Signature block update to indicate that this CPU is in OS now.
616 	 * This needs to be done after the PIL is lowered since on
617 	 * some platforms the update code may block.
618 	 */
619 	CPU_SIGNATURE(OS_SIG, SIGST_RUN, SIGSUBST_NULL, cp->cpu_id);
620 
621 	/*
622 	 * park the slave thread in a safe/quiet state and wait for the master
623 	 * to finish configuring this CPU before proceeding to thread_exit().
624 	 */
625 	while (((volatile ushort_t)cp->cpu_flags) & CPU_QUIESCED)
626 		DELAY(1);
627 
628 	/*
629 	 * Initialize CPC CPU state.
630 	 */
631 	kcpc_hw_startup_cpu(original_flags);
632 
633 	/*
634 	 * Notify the PG subsystem that the CPU  has started
635 	 */
636 	pg_cmt_cpu_startup(CPU);
637 
638 	/*
639 	 * Now we are done with the startup thread, so free it up.
640 	 */
641 	thread_exit();
642 	cmn_err(CE_PANIC, "slave_startup: cannot return");
643 	/*NOTREACHED*/
644 }
645 
646 extern struct cpu	*cpu[NCPU];	/* pointers to all CPUs */
647 
648 /*
649  * cpu_bringup_set is a tunable (via /etc/system, debugger, etc.) that
650  * can be used during debugging to control which processors are brought
651  * online at boot time.  The variable represents a bitmap of the id's
652  * of the processors that will be brought online.  The initialization
653  * of this variable depends on the type of cpuset_t, which varies
654  * depending on the number of processors supported (see cpuvar.h).
655  */
656 cpuset_t cpu_bringup_set;
657 
658 
659 /*
660  * Generic start-all cpus entry.  Typically used during cold initialization.
661  * Note that cold start cpus are initialized into the online state.
662  */
663 /*ARGSUSED*/
664 void
665 start_other_cpus(int flag)
666 {
667 	int cpuid;
668 	extern void idlestop_init(void);
669 	int bootcpu;
670 
671 	/*
672 	 * Check if cpu_bringup_set has been explicitly set before
673 	 * initializing it.
674 	 */
675 	if (CPUSET_ISNULL(cpu_bringup_set)) {
676 #ifdef MPSAS
677 		/* just CPU 0 */
678 		CPUSET_ADD(cpu_bringup_set, 0);
679 #else
680 		CPUSET_ALL(cpu_bringup_set);
681 #endif
682 	}
683 
684 	if (&cpu_feature_init)
685 		cpu_feature_init();
686 
687 	/*
688 	 * Initialize CPC.
689 	 */
690 	kcpc_hw_init();
691 
692 	mutex_enter(&cpu_lock);
693 
694 	/*
695 	 * Initialize our own cpu_info.
696 	 */
697 	init_cpu_info(CPU);
698 
699 	/*
700 	 * Initialize CPU 0 cpu module private data area, including scrubber.
701 	 */
702 	cpu_init_private(CPU);
703 	populate_idstr(CPU);
704 
705 	/*
706 	 * perform such initialization as is needed
707 	 * to be able to take CPUs on- and off-line.
708 	 */
709 	cpu_pause_init();
710 	xc_init();		/* initialize processor crosscalls */
711 	idlestop_init();
712 
713 	if (!use_mp) {
714 		mutex_exit(&cpu_lock);
715 		cmn_err(CE_CONT, "?***** Not in MP mode\n");
716 		return;
717 	}
718 	/*
719 	 * should we be initializing this cpu?
720 	 */
721 	bootcpu = getprocessorid();
722 
723 	/*
724 	 * launch all the slave cpus now
725 	 */
726 	for (cpuid = 0; cpuid < NCPU; cpuid++) {
727 		pnode_t nodeid = cpunodes[cpuid].nodeid;
728 
729 		if (nodeid == (pnode_t)0)
730 			continue;
731 
732 		if (cpuid == bootcpu) {
733 			if (!CPU_IN_SET(cpu_bringup_set, cpuid)) {
734 				cmn_err(CE_WARN, "boot cpu not a member "
735 				    "of cpu_bringup_set, adding it");
736 				CPUSET_ADD(cpu_bringup_set, cpuid);
737 			}
738 			continue;
739 		}
740 		if (!CPU_IN_SET(cpu_bringup_set, cpuid))
741 			continue;
742 
743 		ASSERT(cpu[cpuid] == NULL);
744 
745 		if (setup_cpu_common(cpuid)) {
746 			cmn_err(CE_PANIC, "cpu%d: setup failed", cpuid);
747 		}
748 
749 		common_startup_init(cpu[cpuid], cpuid);
750 
751 		start_cpu(cpuid, cold_flag_set);
752 		/*
753 		 * Because slave_startup() gets fired off after init()
754 		 * starts, we can't use the '?' trick to do 'boot -v'
755 		 * printing - so we always direct the 'cpu .. online'
756 		 * messages to the log.
757 		 */
758 		cmn_err(CE_CONT, "!cpu%d initialization complete - online\n",
759 		    cpuid);
760 
761 		cpu_state_change_notify(cpuid, CPU_SETUP);
762 
763 		if (dtrace_cpu_init != NULL)
764 			(*dtrace_cpu_init)(cpuid);
765 	}
766 
767 	/*
768 	 * since all the cpus are online now, redistribute interrupts to them.
769 	 */
770 	intr_redist_all_cpus();
771 
772 	mutex_exit(&cpu_lock);
773 
774 	/*
775 	 * Start the Ecache scrubber.  Must be done after all calls to
776 	 * cpu_init_private for every cpu (including CPU 0).
777 	 */
778 	cpu_init_cache_scrub();
779 
780 	if (&cpu_mp_init)
781 		cpu_mp_init();
782 }
783