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