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, NULL, "Kernel SMP"); 74 75 SYSCTL_UINT(_kern_smp, OID_AUTO, maxid, CTLFLAG_RD, &mp_maxid, 0, 76 "Max CPU ID."); 77 78 SYSCTL_INT(_kern_smp, OID_AUTO, maxcpus, CTLFLAG_RD, &mp_maxcpus, 0, 79 "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, &smp_disabled, 0, 87 "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, &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[3]; 113 static volatile int smp_rv_generation; 114 115 /* 116 * Shared mutex to restrict busywaits between smp_rendezvous() and 117 * smp(_targeted)_tlb_shootdown(). A deadlock occurs if both of these 118 * functions trigger at once and cause multiple CPUs to busywait with 119 * interrupts disabled. 120 */ 121 struct mtx smp_ipi_mtx; 122 123 /* 124 * Let the MD SMP code initialize mp_maxid very early if it can. 125 */ 126 static void 127 mp_setmaxid(void *dummy) 128 { 129 cpu_mp_setmaxid(); 130 } 131 SYSINIT(cpu_mp_setmaxid, SI_SUB_TUNABLES, SI_ORDER_FIRST, mp_setmaxid, NULL); 132 133 /* 134 * Call the MD SMP initialization code. 135 */ 136 static void 137 mp_start(void *dummy) 138 { 139 140 mtx_init(&smp_ipi_mtx, "smp rendezvous", NULL, MTX_SPIN); 141 142 /* Probe for MP hardware. */ 143 if (smp_disabled != 0 || cpu_mp_probe() == 0) { 144 mp_ncpus = 1; 145 all_cpus = PCPU_GET(cpumask); 146 return; 147 } 148 149 cpu_mp_start(); 150 printf("FreeBSD/SMP: Multiprocessor System Detected: %d CPUs\n", 151 mp_ncpus); 152 cpu_mp_announce(); 153 } 154 SYSINIT(cpu_mp, SI_SUB_CPU, SI_ORDER_THIRD, mp_start, NULL); 155 156 void 157 forward_signal(struct thread *td) 158 { 159 int id; 160 161 /* 162 * signotify() has already set TDF_ASTPENDING and TDF_NEEDSIGCHECK on 163 * this thread, so all we need to do is poke it if it is currently 164 * executing so that it executes ast(). 165 */ 166 THREAD_LOCK_ASSERT(td, MA_OWNED); 167 KASSERT(TD_IS_RUNNING(td), 168 ("forward_signal: thread is not TDS_RUNNING")); 169 170 CTR1(KTR_SMP, "forward_signal(%p)", td->td_proc); 171 172 if (!smp_started || cold || panicstr) 173 return; 174 if (!forward_signal_enabled) 175 return; 176 177 /* No need to IPI ourself. */ 178 if (td == curthread) 179 return; 180 181 id = td->td_oncpu; 182 if (id == NOCPU) 183 return; 184 ipi_cpu(id, IPI_AST); 185 } 186 187 /* 188 * When called the executing CPU will send an IPI to all other CPUs 189 * requesting that they halt execution. 190 * 191 * Usually (but not necessarily) called with 'other_cpus' as its arg. 192 * 193 * - Signals all CPUs in map to stop. 194 * - Waits for each to stop. 195 * 196 * Returns: 197 * -1: error 198 * 0: NA 199 * 1: ok 200 * 201 */ 202 static int 203 generic_stop_cpus(cpuset_t map, u_int type) 204 { 205 #ifdef KTR 206 char cpusetbuf[CPUSETBUFSIZ]; 207 #endif 208 static volatile u_int stopping_cpu = NOCPU; 209 int i; 210 211 KASSERT( 212 #if defined(__amd64__) 213 type == IPI_STOP || type == IPI_STOP_HARD || type == IPI_SUSPEND, 214 #else 215 type == IPI_STOP || type == IPI_STOP_HARD, 216 #endif 217 ("%s: invalid stop type", __func__)); 218 219 if (!smp_started) 220 return (0); 221 222 CTR2(KTR_SMP, "stop_cpus(%s) with %u type", 223 cpusetobj_strprint(cpusetbuf, &map), type); 224 225 if (stopping_cpu != PCPU_GET(cpuid)) 226 while (atomic_cmpset_int(&stopping_cpu, NOCPU, 227 PCPU_GET(cpuid)) == 0) 228 while (stopping_cpu != NOCPU) 229 cpu_spinwait(); /* spin */ 230 231 /* send the stop IPI to all CPUs in map */ 232 ipi_selected(map, type); 233 234 i = 0; 235 while (!CPU_SUBSET(&stopped_cpus, &map)) { 236 /* spin */ 237 cpu_spinwait(); 238 i++; 239 #ifdef DIAGNOSTIC 240 if (i == 100000) { 241 printf("timeout stopping cpus\n"); 242 break; 243 } 244 #endif 245 } 246 247 stopping_cpu = NOCPU; 248 return (1); 249 } 250 251 int 252 stop_cpus(cpuset_t map) 253 { 254 255 return (generic_stop_cpus(map, IPI_STOP)); 256 } 257 258 int 259 stop_cpus_hard(cpuset_t map) 260 { 261 262 return (generic_stop_cpus(map, IPI_STOP_HARD)); 263 } 264 265 #if defined(__amd64__) 266 int 267 suspend_cpus(cpuset_t map) 268 { 269 270 return (generic_stop_cpus(map, IPI_SUSPEND)); 271 } 272 #endif 273 274 /* 275 * Called by a CPU to restart stopped CPUs. 276 * 277 * Usually (but not necessarily) called with 'stopped_cpus' as its arg. 278 * 279 * - Signals all CPUs in map to restart. 280 * - Waits for each to restart. 281 * 282 * Returns: 283 * -1: error 284 * 0: NA 285 * 1: ok 286 */ 287 int 288 restart_cpus(cpuset_t map) 289 { 290 #ifdef KTR 291 char cpusetbuf[CPUSETBUFSIZ]; 292 #endif 293 294 if (!smp_started) 295 return 0; 296 297 CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); 298 299 /* signal other cpus to restart */ 300 CPU_COPY_STORE_REL(&map, &started_cpus); 301 302 /* wait for each to clear its bit */ 303 while (CPU_OVERLAP(&stopped_cpus, &map)) 304 cpu_spinwait(); 305 306 return 1; 307 } 308 309 /* 310 * All-CPU rendezvous. CPUs are signalled, all execute the setup function 311 * (if specified), rendezvous, execute the action function (if specified), 312 * rendezvous again, execute the teardown function (if specified), and then 313 * resume. 314 * 315 * Note that the supplied external functions _must_ be reentrant and aware 316 * that they are running in parallel and in an unknown lock context. 317 */ 318 void 319 smp_rendezvous_action(void) 320 { 321 struct thread *td; 322 void *local_func_arg; 323 void (*local_setup_func)(void*); 324 void (*local_action_func)(void*); 325 void (*local_teardown_func)(void*); 326 int generation; 327 #ifdef INVARIANTS 328 int owepreempt; 329 #endif 330 331 /* Ensure we have up-to-date values. */ 332 atomic_add_acq_int(&smp_rv_waiters[0], 1); 333 while (smp_rv_waiters[0] < smp_rv_ncpus) 334 cpu_spinwait(); 335 336 /* Fetch rendezvous parameters after acquire barrier. */ 337 local_func_arg = smp_rv_func_arg; 338 local_setup_func = smp_rv_setup_func; 339 local_action_func = smp_rv_action_func; 340 local_teardown_func = smp_rv_teardown_func; 341 generation = smp_rv_generation; 342 343 /* 344 * Use a nested critical section to prevent any preemptions 345 * from occurring during a rendezvous action routine. 346 * Specifically, if a rendezvous handler is invoked via an IPI 347 * and the interrupted thread was in the critical_exit() 348 * function after setting td_critnest to 0 but before 349 * performing a deferred preemption, this routine can be 350 * invoked with td_critnest set to 0 and td_owepreempt true. 351 * In that case, a critical_exit() during the rendezvous 352 * action would trigger a preemption which is not permitted in 353 * a rendezvous action. To fix this, wrap all of the 354 * rendezvous action handlers in a critical section. We 355 * cannot use a regular critical section however as having 356 * critical_exit() preempt from this routine would also be 357 * problematic (the preemption must not occur before the IPI 358 * has been acknowledged via an EOI). Instead, we 359 * intentionally ignore td_owepreempt when leaving the 360 * critical section. This should be harmless because we do 361 * not permit rendezvous action routines to schedule threads, 362 * and thus td_owepreempt should never transition from 0 to 1 363 * during this routine. 364 */ 365 td = curthread; 366 td->td_critnest++; 367 #ifdef INVARIANTS 368 owepreempt = td->td_owepreempt; 369 #endif 370 371 /* 372 * If requested, run a setup function before the main action 373 * function. Ensure all CPUs have completed the setup 374 * function before moving on to the action function. 375 */ 376 if (local_setup_func != smp_no_rendevous_barrier) { 377 if (smp_rv_setup_func != NULL) 378 smp_rv_setup_func(smp_rv_func_arg); 379 atomic_add_int(&smp_rv_waiters[1], 1); 380 while (smp_rv_waiters[1] < smp_rv_ncpus) 381 cpu_spinwait(); 382 } 383 384 if (local_action_func != NULL) 385 local_action_func(local_func_arg); 386 387 /* 388 * Signal that the main action has been completed. If a 389 * full exit rendezvous is requested, then all CPUs will 390 * wait here until all CPUs have finished the main action. 391 * 392 * Note that the write by the last CPU to finish the action 393 * may become visible to different CPUs at different times. 394 * As a result, the CPU that initiated the rendezvous may 395 * exit the rendezvous and drop the lock allowing another 396 * rendezvous to be initiated on the same CPU or a different 397 * CPU. In that case the exit sentinel may be cleared before 398 * all CPUs have noticed causing those CPUs to hang forever. 399 * Workaround this by using a generation count to notice when 400 * this race occurs and to exit the rendezvous in that case. 401 */ 402 MPASS(generation == smp_rv_generation); 403 atomic_add_int(&smp_rv_waiters[2], 1); 404 if (local_teardown_func != smp_no_rendevous_barrier) { 405 while (smp_rv_waiters[2] < smp_rv_ncpus && 406 generation == smp_rv_generation) 407 cpu_spinwait(); 408 409 if (local_teardown_func != NULL) 410 local_teardown_func(local_func_arg); 411 } 412 413 td->td_critnest--; 414 KASSERT(owepreempt == td->td_owepreempt, 415 ("rendezvous action changed td_owepreempt")); 416 } 417 418 void 419 smp_rendezvous_cpus(cpuset_t map, 420 void (* setup_func)(void *), 421 void (* action_func)(void *), 422 void (* teardown_func)(void *), 423 void *arg) 424 { 425 int curcpumap, i, ncpus = 0; 426 427 if (!smp_started) { 428 if (setup_func != NULL) 429 setup_func(arg); 430 if (action_func != NULL) 431 action_func(arg); 432 if (teardown_func != NULL) 433 teardown_func(arg); 434 return; 435 } 436 437 CPU_FOREACH(i) { 438 if (CPU_ISSET(i, &map)) 439 ncpus++; 440 } 441 if (ncpus == 0) 442 panic("ncpus is 0 with non-zero map"); 443 444 mtx_lock_spin(&smp_ipi_mtx); 445 446 atomic_add_acq_int(&smp_rv_generation, 1); 447 448 /* Pass rendezvous parameters via global variables. */ 449 smp_rv_ncpus = ncpus; 450 smp_rv_setup_func = setup_func; 451 smp_rv_action_func = action_func; 452 smp_rv_teardown_func = teardown_func; 453 smp_rv_func_arg = arg; 454 smp_rv_waiters[1] = 0; 455 smp_rv_waiters[2] = 0; 456 atomic_store_rel_int(&smp_rv_waiters[0], 0); 457 458 /* 459 * Signal other processors, which will enter the IPI with 460 * interrupts off. 461 */ 462 curcpumap = CPU_ISSET(curcpu, &map); 463 CPU_CLR(curcpu, &map); 464 ipi_selected(map, IPI_RENDEZVOUS); 465 466 /* Check if the current CPU is in the map */ 467 if (curcpumap != 0) 468 smp_rendezvous_action(); 469 470 /* 471 * If the caller did not request an exit barrier to be enforced 472 * on each CPU, ensure that this CPU waits for all the other 473 * CPUs to finish the rendezvous. 474 */ 475 if (teardown_func == smp_no_rendevous_barrier) 476 while (atomic_load_acq_int(&smp_rv_waiters[2]) < ncpus) 477 cpu_spinwait(); 478 479 mtx_unlock_spin(&smp_ipi_mtx); 480 } 481 482 void 483 smp_rendezvous(void (* setup_func)(void *), 484 void (* action_func)(void *), 485 void (* teardown_func)(void *), 486 void *arg) 487 { 488 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); 489 } 490 491 static struct cpu_group group[MAXCPU]; 492 493 struct cpu_group * 494 smp_topo(void) 495 { 496 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 497 struct cpu_group *top; 498 499 /* 500 * Check for a fake topology request for debugging purposes. 501 */ 502 switch (smp_topology) { 503 case 1: 504 /* Dual core with no sharing. */ 505 top = smp_topo_1level(CG_SHARE_NONE, 2, 0); 506 break; 507 case 2: 508 /* No topology, all cpus are equal. */ 509 top = smp_topo_none(); 510 break; 511 case 3: 512 /* Dual core with shared L2. */ 513 top = smp_topo_1level(CG_SHARE_L2, 2, 0); 514 break; 515 case 4: 516 /* quad core, shared l3 among each package, private l2. */ 517 top = smp_topo_1level(CG_SHARE_L3, 4, 0); 518 break; 519 case 5: 520 /* quad core, 2 dualcore parts on each package share l2. */ 521 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); 522 break; 523 case 6: 524 /* Single-core 2xHTT */ 525 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); 526 break; 527 case 7: 528 /* quad core with a shared l3, 8 threads sharing L2. */ 529 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, 530 CG_FLAG_SMT); 531 break; 532 default: 533 /* Default, ask the system what it wants. */ 534 top = cpu_topo(); 535 break; 536 } 537 /* 538 * Verify the returned topology. 539 */ 540 if (top->cg_count != mp_ncpus) 541 panic("Built bad topology at %p. CPU count %d != %d", 542 top, top->cg_count, mp_ncpus); 543 if (CPU_CMP(&top->cg_mask, &all_cpus)) 544 panic("Built bad topology at %p. CPU mask (%s) != (%s)", 545 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), 546 cpusetobj_strprint(cpusetbuf2, &all_cpus)); 547 return (top); 548 } 549 550 struct cpu_group * 551 smp_topo_none(void) 552 { 553 struct cpu_group *top; 554 555 top = &group[0]; 556 top->cg_parent = NULL; 557 top->cg_child = NULL; 558 top->cg_mask = all_cpus; 559 top->cg_count = mp_ncpus; 560 top->cg_children = 0; 561 top->cg_level = CG_SHARE_NONE; 562 top->cg_flags = 0; 563 564 return (top); 565 } 566 567 static int 568 smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, 569 int count, int flags, int start) 570 { 571 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 572 cpuset_t mask; 573 int i; 574 575 CPU_ZERO(&mask); 576 for (i = 0; i < count; i++, start++) 577 CPU_SET(start, &mask); 578 child->cg_parent = parent; 579 child->cg_child = NULL; 580 child->cg_children = 0; 581 child->cg_level = share; 582 child->cg_count = count; 583 child->cg_flags = flags; 584 child->cg_mask = mask; 585 parent->cg_children++; 586 for (; parent != NULL; parent = parent->cg_parent) { 587 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) 588 panic("Duplicate children in %p. mask (%s) child (%s)", 589 parent, 590 cpusetobj_strprint(cpusetbuf, &parent->cg_mask), 591 cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); 592 CPU_OR(&parent->cg_mask, &child->cg_mask); 593 parent->cg_count += child->cg_count; 594 } 595 596 return (start); 597 } 598 599 struct cpu_group * 600 smp_topo_1level(int share, int count, int flags) 601 { 602 struct cpu_group *child; 603 struct cpu_group *top; 604 int packages; 605 int cpu; 606 int i; 607 608 cpu = 0; 609 top = &group[0]; 610 packages = mp_ncpus / count; 611 top->cg_child = child = &group[1]; 612 top->cg_level = CG_SHARE_NONE; 613 for (i = 0; i < packages; i++, child++) 614 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); 615 return (top); 616 } 617 618 struct cpu_group * 619 smp_topo_2level(int l2share, int l2count, int l1share, int l1count, 620 int l1flags) 621 { 622 struct cpu_group *top; 623 struct cpu_group *l1g; 624 struct cpu_group *l2g; 625 int cpu; 626 int i; 627 int j; 628 629 cpu = 0; 630 top = &group[0]; 631 l2g = &group[1]; 632 top->cg_child = l2g; 633 top->cg_level = CG_SHARE_NONE; 634 top->cg_children = mp_ncpus / (l2count * l1count); 635 l1g = l2g + top->cg_children; 636 for (i = 0; i < top->cg_children; i++, l2g++) { 637 l2g->cg_parent = top; 638 l2g->cg_child = l1g; 639 l2g->cg_level = l2share; 640 for (j = 0; j < l2count; j++, l1g++) 641 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, 642 l1flags, cpu); 643 } 644 return (top); 645 } 646 647 648 struct cpu_group * 649 smp_topo_find(struct cpu_group *top, int cpu) 650 { 651 struct cpu_group *cg; 652 cpuset_t mask; 653 int children; 654 int i; 655 656 CPU_SETOF(cpu, &mask); 657 cg = top; 658 for (;;) { 659 if (!CPU_OVERLAP(&cg->cg_mask, &mask)) 660 return (NULL); 661 if (cg->cg_children == 0) 662 return (cg); 663 children = cg->cg_children; 664 for (i = 0, cg = cg->cg_child; i < children; cg++, i++) 665 if (CPU_OVERLAP(&cg->cg_mask, &mask)) 666 break; 667 } 668 return (NULL); 669 } 670 #else /* !SMP */ 671 672 void 673 smp_rendezvous_cpus(cpuset_t map, 674 void (*setup_func)(void *), 675 void (*action_func)(void *), 676 void (*teardown_func)(void *), 677 void *arg) 678 { 679 if (setup_func != NULL) 680 setup_func(arg); 681 if (action_func != NULL) 682 action_func(arg); 683 if (teardown_func != NULL) 684 teardown_func(arg); 685 } 686 687 void 688 smp_rendezvous(void (*setup_func)(void *), 689 void (*action_func)(void *), 690 void (*teardown_func)(void *), 691 void *arg) 692 { 693 694 if (setup_func != NULL) 695 setup_func(arg); 696 if (action_func != NULL) 697 action_func(arg); 698 if (teardown_func != NULL) 699 teardown_func(arg); 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 all_cpus = PCPU_GET(cpumask); 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 } 725