FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_smp.c
1 /*-
2 * Copyright (c) 2001, John Baldwin <jhb@FreeBSD.org>.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 /*
28 * This module holds the global variables and machine independent functions
29 * used for the kernel SMP support.
30 */
31
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/ktr.h>
39 #include <sys/proc.h>
40 #include <sys/bus.h>
41 #include <sys/lock.h>
42 #include <sys/mutex.h>
43 #include <sys/pcpu.h>
44 #include <sys/smp.h>
45 #include <sys/sysctl.h>
46
47 #include <machine/cpu.h>
48 #include <machine/smp.h>
49
50 #include "opt_sched.h"
51
52 #ifdef SMP
53 volatile cpuset_t stopped_cpus;
54 volatile cpuset_t started_cpus;
55 cpuset_t hlt_cpus_mask;
56 cpuset_t logical_cpus_mask;
57
58 void (*cpustop_restartfunc)(void);
59 #endif
60 /* This is used in modules that need to work in both SMP and UP. */
61 cpuset_t all_cpus;
62
63 int mp_ncpus;
64 /* export this for libkvm consumers. */
65 int mp_maxcpus = MAXCPU;
66
67 volatile int smp_started;
68 u_int mp_maxid;
69
70 static SYSCTL_NODE(_kern, OID_AUTO, smp, CTLFLAG_RD|CTLFLAG_CAPRD, NULL,
71 "Kernel SMP");
72
73 SYSCTL_INT(_kern_smp, OID_AUTO, maxid, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxid, 0,
74 "Max CPU ID.");
75
76 SYSCTL_INT(_kern_smp, OID_AUTO, maxcpus, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxcpus,
77 0, "Max number of CPUs that the system was compiled for.");
78
79 int smp_active = 0; /* are the APs allowed to run? */
80 SYSCTL_INT(_kern_smp, OID_AUTO, active, CTLFLAG_RW, &smp_active, 0,
81 "Number of Auxillary Processors (APs) that were successfully started");
82
83 int smp_disabled = 0; /* has smp been disabled? */
84 SYSCTL_INT(_kern_smp, OID_AUTO, disabled, CTLFLAG_RDTUN|CTLFLAG_CAPRD,
85 &smp_disabled, 0, "SMP has been disabled from the loader");
86 TUNABLE_INT("kern.smp.disabled", &smp_disabled);
87
88 int smp_cpus = 1; /* how many cpu's running */
89 SYSCTL_INT(_kern_smp, OID_AUTO, cpus, CTLFLAG_RD|CTLFLAG_CAPRD, &smp_cpus, 0,
90 "Number of CPUs online");
91
92 int smp_topology = 0; /* Which topology we're using. */
93 SYSCTL_INT(_kern_smp, OID_AUTO, topology, CTLFLAG_RD, &smp_topology, 0,
94 "Topology override setting; 0 is default provided by hardware.");
95 TUNABLE_INT("kern.smp.topology", &smp_topology);
96
97 #ifdef SMP
98 /* Enable forwarding of a signal to a process running on a different CPU */
99 static int forward_signal_enabled = 1;
100 SYSCTL_INT(_kern_smp, OID_AUTO, forward_signal_enabled, CTLFLAG_RW,
101 &forward_signal_enabled, 0,
102 "Forwarding of a signal to a process on a different CPU");
103
104 /* Variables needed for SMP rendezvous. */
105 static volatile int smp_rv_ncpus;
106 static void (*volatile smp_rv_setup_func)(void *arg);
107 static void (*volatile smp_rv_action_func)(void *arg);
108 static void (*volatile smp_rv_teardown_func)(void *arg);
109 static void *volatile smp_rv_func_arg;
110 static volatile int smp_rv_waiters[4];
111
112 /*
113 * Shared mutex to restrict busywaits between smp_rendezvous() and
114 * smp(_targeted)_tlb_shootdown(). A deadlock occurs if both of these
115 * functions trigger at once and cause multiple CPUs to busywait with
116 * interrupts disabled.
117 */
118 struct mtx smp_ipi_mtx;
119
120 /*
121 * Let the MD SMP code initialize mp_maxid very early if it can.
122 */
123 static void
124 mp_setmaxid(void *dummy)
125 {
126 cpu_mp_setmaxid();
127 }
128 SYSINIT(cpu_mp_setmaxid, SI_SUB_TUNABLES, SI_ORDER_FIRST, mp_setmaxid, NULL);
129
130 /*
131 * Call the MD SMP initialization code.
132 */
133 static void
134 mp_start(void *dummy)
135 {
136
137 mtx_init(&smp_ipi_mtx, "smp rendezvous", NULL, MTX_SPIN);
138
139 /* Probe for MP hardware. */
140 if (smp_disabled != 0 || cpu_mp_probe() == 0) {
141 mp_ncpus = 1;
142 CPU_SETOF(PCPU_GET(cpuid), &all_cpus);
143 return;
144 }
145
146 cpu_mp_start();
147 printf("FreeBSD/SMP: Multiprocessor System Detected: %d CPUs\n",
148 mp_ncpus);
149 cpu_mp_announce();
150 }
151 SYSINIT(cpu_mp, SI_SUB_CPU, SI_ORDER_THIRD, mp_start, NULL);
152
153 void
154 forward_signal(struct thread *td)
155 {
156 int id;
157
158 /*
159 * signotify() has already set TDF_ASTPENDING and TDF_NEEDSIGCHECK on
160 * this thread, so all we need to do is poke it if it is currently
161 * executing so that it executes ast().
162 */
163 THREAD_LOCK_ASSERT(td, MA_OWNED);
164 KASSERT(TD_IS_RUNNING(td),
165 ("forward_signal: thread is not TDS_RUNNING"));
166
167 CTR1(KTR_SMP, "forward_signal(%p)", td->td_proc);
168
169 if (!smp_started || cold || panicstr)
170 return;
171 if (!forward_signal_enabled)
172 return;
173
174 /* No need to IPI ourself. */
175 if (td == curthread)
176 return;
177
178 id = td->td_oncpu;
179 if (id == NOCPU)
180 return;
181 ipi_cpu(id, IPI_AST);
182 }
183
184 /*
185 * When called the executing CPU will send an IPI to all other CPUs
186 * requesting that they halt execution.
187 *
188 * Usually (but not necessarily) called with 'other_cpus' as its arg.
189 *
190 * - Signals all CPUs in map to stop.
191 * - Waits for each to stop.
192 *
193 * Returns:
194 * -1: error
195 * 0: NA
196 * 1: ok
197 *
198 */
199 static int
200 generic_stop_cpus(cpuset_t map, u_int type)
201 {
202 #ifdef KTR
203 char cpusetbuf[CPUSETBUFSIZ];
204 #endif
205 static volatile u_int stopping_cpu = NOCPU;
206 int i;
207
208 KASSERT(
209 #if defined(__amd64__) || defined(__i386__)
210 type == IPI_STOP || type == IPI_STOP_HARD || type == IPI_SUSPEND,
211 #else
212 type == IPI_STOP || type == IPI_STOP_HARD,
213 #endif
214 ("%s: invalid stop type", __func__));
215
216 if (!smp_started)
217 return (0);
218
219 CTR2(KTR_SMP, "stop_cpus(%s) with %u type",
220 cpusetobj_strprint(cpusetbuf, &map), type);
221
222 if (stopping_cpu != PCPU_GET(cpuid))
223 while (atomic_cmpset_int(&stopping_cpu, NOCPU,
224 PCPU_GET(cpuid)) == 0)
225 while (stopping_cpu != NOCPU)
226 cpu_spinwait(); /* spin */
227
228 /* send the stop IPI to all CPUs in map */
229 ipi_selected(map, type);
230
231 i = 0;
232 while (!CPU_SUBSET(&stopped_cpus, &map)) {
233 /* spin */
234 cpu_spinwait();
235 i++;
236 if (i == 100000000) {
237 printf("timeout stopping cpus\n");
238 break;
239 }
240 }
241
242 stopping_cpu = NOCPU;
243 return (1);
244 }
245
246 int
247 stop_cpus(cpuset_t map)
248 {
249
250 return (generic_stop_cpus(map, IPI_STOP));
251 }
252
253 int
254 stop_cpus_hard(cpuset_t map)
255 {
256
257 return (generic_stop_cpus(map, IPI_STOP_HARD));
258 }
259
260 #if defined(__amd64__) || defined(__i386__)
261 int
262 suspend_cpus(cpuset_t map)
263 {
264
265 return (generic_stop_cpus(map, IPI_SUSPEND));
266 }
267 #endif
268
269 /*
270 * Called by a CPU to restart stopped CPUs.
271 *
272 * Usually (but not necessarily) called with 'stopped_cpus' as its arg.
273 *
274 * - Signals all CPUs in map to restart.
275 * - Waits for each to restart.
276 *
277 * Returns:
278 * -1: error
279 * 0: NA
280 * 1: ok
281 */
282 int
283 restart_cpus(cpuset_t map)
284 {
285 #ifdef KTR
286 char cpusetbuf[CPUSETBUFSIZ];
287 #endif
288
289 if (!smp_started)
290 return 0;
291
292 CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map));
293
294 /* signal other cpus to restart */
295 CPU_COPY_STORE_REL(&map, &started_cpus);
296
297 /* wait for each to clear its bit */
298 while (CPU_OVERLAP(&stopped_cpus, &map))
299 cpu_spinwait();
300
301 return 1;
302 }
303
304 /*
305 * All-CPU rendezvous. CPUs are signalled, all execute the setup function
306 * (if specified), rendezvous, execute the action function (if specified),
307 * rendezvous again, execute the teardown function (if specified), and then
308 * resume.
309 *
310 * Note that the supplied external functions _must_ be reentrant and aware
311 * that they are running in parallel and in an unknown lock context.
312 */
313 void
314 smp_rendezvous_action(void)
315 {
316 struct thread *td;
317 void *local_func_arg;
318 void (*local_setup_func)(void*);
319 void (*local_action_func)(void*);
320 void (*local_teardown_func)(void*);
321 #ifdef INVARIANTS
322 int owepreempt;
323 #endif
324
325 /* Ensure we have up-to-date values. */
326 atomic_add_acq_int(&smp_rv_waiters[0], 1);
327 while (smp_rv_waiters[0] < smp_rv_ncpus)
328 cpu_spinwait();
329
330 /* Fetch rendezvous parameters after acquire barrier. */
331 local_func_arg = smp_rv_func_arg;
332 local_setup_func = smp_rv_setup_func;
333 local_action_func = smp_rv_action_func;
334 local_teardown_func = smp_rv_teardown_func;
335
336 /*
337 * Use a nested critical section to prevent any preemptions
338 * from occurring during a rendezvous action routine.
339 * Specifically, if a rendezvous handler is invoked via an IPI
340 * and the interrupted thread was in the critical_exit()
341 * function after setting td_critnest to 0 but before
342 * performing a deferred preemption, this routine can be
343 * invoked with td_critnest set to 0 and td_owepreempt true.
344 * In that case, a critical_exit() during the rendezvous
345 * action would trigger a preemption which is not permitted in
346 * a rendezvous action. To fix this, wrap all of the
347 * rendezvous action handlers in a critical section. We
348 * cannot use a regular critical section however as having
349 * critical_exit() preempt from this routine would also be
350 * problematic (the preemption must not occur before the IPI
351 * has been acknowledged via an EOI). Instead, we
352 * intentionally ignore td_owepreempt when leaving the
353 * critical section. This should be harmless because we do
354 * not permit rendezvous action routines to schedule threads,
355 * and thus td_owepreempt should never transition from 0 to 1
356 * during this routine.
357 */
358 td = curthread;
359 td->td_critnest++;
360 #ifdef INVARIANTS
361 owepreempt = td->td_owepreempt;
362 #endif
363
364 /*
365 * If requested, run a setup function before the main action
366 * function. Ensure all CPUs have completed the setup
367 * function before moving on to the action function.
368 */
369 if (local_setup_func != smp_no_rendevous_barrier) {
370 if (smp_rv_setup_func != NULL)
371 smp_rv_setup_func(smp_rv_func_arg);
372 atomic_add_int(&smp_rv_waiters[1], 1);
373 while (smp_rv_waiters[1] < smp_rv_ncpus)
374 cpu_spinwait();
375 }
376
377 if (local_action_func != NULL)
378 local_action_func(local_func_arg);
379
380 if (local_teardown_func != smp_no_rendevous_barrier) {
381 /*
382 * Signal that the main action has been completed. If a
383 * full exit rendezvous is requested, then all CPUs will
384 * wait here until all CPUs have finished the main action.
385 */
386 atomic_add_int(&smp_rv_waiters[2], 1);
387 while (smp_rv_waiters[2] < smp_rv_ncpus)
388 cpu_spinwait();
389
390 if (local_teardown_func != NULL)
391 local_teardown_func(local_func_arg);
392 }
393
394 /*
395 * Signal that the rendezvous is fully completed by this CPU.
396 * This means that no member of smp_rv_* pseudo-structure will be
397 * accessed by this target CPU after this point; in particular,
398 * memory pointed by smp_rv_func_arg.
399 */
400 atomic_add_int(&smp_rv_waiters[3], 1);
401
402 td->td_critnest--;
403 KASSERT(owepreempt == td->td_owepreempt,
404 ("rendezvous action changed td_owepreempt"));
405 }
406
407 void
408 smp_rendezvous_cpus(cpuset_t map,
409 void (* setup_func)(void *),
410 void (* action_func)(void *),
411 void (* teardown_func)(void *),
412 void *arg)
413 {
414 int curcpumap, i, ncpus = 0;
415
416 /* Look comments in the !SMP case. */
417 if (!smp_started) {
418 spinlock_enter();
419 if (setup_func != NULL)
420 setup_func(arg);
421 if (action_func != NULL)
422 action_func(arg);
423 if (teardown_func != NULL)
424 teardown_func(arg);
425 spinlock_exit();
426 return;
427 }
428
429 CPU_FOREACH(i) {
430 if (CPU_ISSET(i, &map))
431 ncpus++;
432 }
433 if (ncpus == 0)
434 panic("ncpus is 0 with non-zero map");
435
436 mtx_lock_spin(&smp_ipi_mtx);
437
438 /* Pass rendezvous parameters via global variables. */
439 smp_rv_ncpus = ncpus;
440 smp_rv_setup_func = setup_func;
441 smp_rv_action_func = action_func;
442 smp_rv_teardown_func = teardown_func;
443 smp_rv_func_arg = arg;
444 smp_rv_waiters[1] = 0;
445 smp_rv_waiters[2] = 0;
446 smp_rv_waiters[3] = 0;
447 atomic_store_rel_int(&smp_rv_waiters[0], 0);
448
449 /*
450 * Signal other processors, which will enter the IPI with
451 * interrupts off.
452 */
453 curcpumap = CPU_ISSET(curcpu, &map);
454 CPU_CLR(curcpu, &map);
455 ipi_selected(map, IPI_RENDEZVOUS);
456
457 /* Check if the current CPU is in the map */
458 if (curcpumap != 0)
459 smp_rendezvous_action();
460
461 /*
462 * Ensure that the master CPU waits for all the other
463 * CPUs to finish the rendezvous, so that smp_rv_*
464 * pseudo-structure and the arg are guaranteed to not
465 * be in use.
466 */
467 while (atomic_load_acq_int(&smp_rv_waiters[3]) < ncpus)
468 cpu_spinwait();
469
470 mtx_unlock_spin(&smp_ipi_mtx);
471 }
472
473 void
474 smp_rendezvous(void (* setup_func)(void *),
475 void (* action_func)(void *),
476 void (* teardown_func)(void *),
477 void *arg)
478 {
479 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg);
480 }
481
482 static struct cpu_group group[MAXCPU];
483
484 struct cpu_group *
485 smp_topo(void)
486 {
487 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ];
488 struct cpu_group *top;
489
490 /*
491 * Check for a fake topology request for debugging purposes.
492 */
493 switch (smp_topology) {
494 case 1:
495 /* Dual core with no sharing. */
496 top = smp_topo_1level(CG_SHARE_NONE, 2, 0);
497 break;
498 case 2:
499 /* No topology, all cpus are equal. */
500 top = smp_topo_none();
501 break;
502 case 3:
503 /* Dual core with shared L2. */
504 top = smp_topo_1level(CG_SHARE_L2, 2, 0);
505 break;
506 case 4:
507 /* quad core, shared l3 among each package, private l2. */
508 top = smp_topo_1level(CG_SHARE_L3, 4, 0);
509 break;
510 case 5:
511 /* quad core, 2 dualcore parts on each package share l2. */
512 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0);
513 break;
514 case 6:
515 /* Single-core 2xHTT */
516 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT);
517 break;
518 case 7:
519 /* quad core with a shared l3, 8 threads sharing L2. */
520 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8,
521 CG_FLAG_SMT);
522 break;
523 default:
524 /* Default, ask the system what it wants. */
525 top = cpu_topo();
526 break;
527 }
528 /*
529 * Verify the returned topology.
530 */
531 if (top->cg_count != mp_ncpus)
532 panic("Built bad topology at %p. CPU count %d != %d",
533 top, top->cg_count, mp_ncpus);
534 if (CPU_CMP(&top->cg_mask, &all_cpus))
535 panic("Built bad topology at %p. CPU mask (%s) != (%s)",
536 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask),
537 cpusetobj_strprint(cpusetbuf2, &all_cpus));
538 return (top);
539 }
540
541 struct cpu_group *
542 smp_topo_none(void)
543 {
544 struct cpu_group *top;
545
546 top = &group[0];
547 top->cg_parent = NULL;
548 top->cg_child = NULL;
549 top->cg_mask = all_cpus;
550 top->cg_count = mp_ncpus;
551 top->cg_children = 0;
552 top->cg_level = CG_SHARE_NONE;
553 top->cg_flags = 0;
554
555 return (top);
556 }
557
558 static int
559 smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share,
560 int count, int flags, int start)
561 {
562 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ];
563 cpuset_t mask;
564 int i;
565
566 CPU_ZERO(&mask);
567 for (i = 0; i < count; i++, start++)
568 CPU_SET(start, &mask);
569 child->cg_parent = parent;
570 child->cg_child = NULL;
571 child->cg_children = 0;
572 child->cg_level = share;
573 child->cg_count = count;
574 child->cg_flags = flags;
575 child->cg_mask = mask;
576 parent->cg_children++;
577 for (; parent != NULL; parent = parent->cg_parent) {
578 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask))
579 panic("Duplicate children in %p. mask (%s) child (%s)",
580 parent,
581 cpusetobj_strprint(cpusetbuf, &parent->cg_mask),
582 cpusetobj_strprint(cpusetbuf2, &child->cg_mask));
583 CPU_OR(&parent->cg_mask, &child->cg_mask);
584 parent->cg_count += child->cg_count;
585 }
586
587 return (start);
588 }
589
590 struct cpu_group *
591 smp_topo_1level(int share, int count, int flags)
592 {
593 struct cpu_group *child;
594 struct cpu_group *top;
595 int packages;
596 int cpu;
597 int i;
598
599 cpu = 0;
600 top = &group[0];
601 packages = mp_ncpus / count;
602 top->cg_child = child = &group[1];
603 top->cg_level = CG_SHARE_NONE;
604 for (i = 0; i < packages; i++, child++)
605 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu);
606 return (top);
607 }
608
609 struct cpu_group *
610 smp_topo_2level(int l2share, int l2count, int l1share, int l1count,
611 int l1flags)
612 {
613 struct cpu_group *top;
614 struct cpu_group *l1g;
615 struct cpu_group *l2g;
616 int cpu;
617 int i;
618 int j;
619
620 cpu = 0;
621 top = &group[0];
622 l2g = &group[1];
623 top->cg_child = l2g;
624 top->cg_level = CG_SHARE_NONE;
625 top->cg_children = mp_ncpus / (l2count * l1count);
626 l1g = l2g + top->cg_children;
627 for (i = 0; i < top->cg_children; i++, l2g++) {
628 l2g->cg_parent = top;
629 l2g->cg_child = l1g;
630 l2g->cg_level = l2share;
631 for (j = 0; j < l2count; j++, l1g++)
632 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count,
633 l1flags, cpu);
634 }
635 return (top);
636 }
637
638
639 struct cpu_group *
640 smp_topo_find(struct cpu_group *top, int cpu)
641 {
642 struct cpu_group *cg;
643 cpuset_t mask;
644 int children;
645 int i;
646
647 CPU_SETOF(cpu, &mask);
648 cg = top;
649 for (;;) {
650 if (!CPU_OVERLAP(&cg->cg_mask, &mask))
651 return (NULL);
652 if (cg->cg_children == 0)
653 return (cg);
654 children = cg->cg_children;
655 for (i = 0, cg = cg->cg_child; i < children; cg++, i++)
656 if (CPU_OVERLAP(&cg->cg_mask, &mask))
657 break;
658 }
659 return (NULL);
660 }
661 #else /* !SMP */
662
663 void
664 smp_rendezvous_cpus(cpuset_t map,
665 void (*setup_func)(void *),
666 void (*action_func)(void *),
667 void (*teardown_func)(void *),
668 void *arg)
669 {
670 /*
671 * In the !SMP case we just need to ensure the same initial conditions
672 * as the SMP case.
673 */
674 spinlock_enter();
675 if (setup_func != NULL)
676 setup_func(arg);
677 if (action_func != NULL)
678 action_func(arg);
679 if (teardown_func != NULL)
680 teardown_func(arg);
681 spinlock_exit();
682 }
683
684 void
685 smp_rendezvous(void (*setup_func)(void *),
686 void (*action_func)(void *),
687 void (*teardown_func)(void *),
688 void *arg)
689 {
690
691 /* Look comments in the smp_rendezvous_cpus() case. */
692 spinlock_enter();
693 if (setup_func != NULL)
694 setup_func(arg);
695 if (action_func != NULL)
696 action_func(arg);
697 if (teardown_func != NULL)
698 teardown_func(arg);
699 spinlock_exit();
700 }
701
702 /*
703 * Provide dummy SMP support for UP kernels. Modules that need to use SMP
704 * APIs will still work using this dummy support.
705 */
706 static void
707 mp_setvariables_for_up(void *dummy)
708 {
709 mp_ncpus = 1;
710 mp_maxid = PCPU_GET(cpuid);
711 CPU_SETOF(mp_maxid, &all_cpus);
712 KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero"));
713 }
714 SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST,
715 mp_setvariables_for_up, NULL);
716 #endif /* SMP */
717
718 void
719 smp_no_rendevous_barrier(void *dummy)
720 {
721 #ifdef SMP
722 KASSERT((!smp_started),("smp_no_rendevous called and smp is started"));
723 #endif
724 }
Cache object: 71426b11e8d2f784e35d2af8854379a8
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