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[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 CPU_SETOF(PCPU_GET(cpuid), &all_cpus); 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 if (i == 100000000) { 240 printf("timeout stopping cpus\n"); 241 break; 242 } 243 } 244 245 stopping_cpu = NOCPU; 246 return (1); 247 } 248 249 int 250 stop_cpus(cpuset_t map) 251 { 252 253 return (generic_stop_cpus(map, IPI_STOP)); 254 } 255 256 int 257 stop_cpus_hard(cpuset_t map) 258 { 259 260 return (generic_stop_cpus(map, IPI_STOP_HARD)); 261 } 262 263 #if defined(__amd64__) 264 int 265 suspend_cpus(cpuset_t map) 266 { 267 268 return (generic_stop_cpus(map, IPI_SUSPEND)); 269 } 270 #endif 271 272 /* 273 * Called by a CPU to restart stopped CPUs. 274 * 275 * Usually (but not necessarily) called with 'stopped_cpus' as its arg. 276 * 277 * - Signals all CPUs in map to restart. 278 * - Waits for each to restart. 279 * 280 * Returns: 281 * -1: error 282 * 0: NA 283 * 1: ok 284 */ 285 int 286 restart_cpus(cpuset_t map) 287 { 288 #ifdef KTR 289 char cpusetbuf[CPUSETBUFSIZ]; 290 #endif 291 292 if (!smp_started) 293 return 0; 294 295 CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); 296 297 /* signal other cpus to restart */ 298 CPU_COPY_STORE_REL(&map, &started_cpus); 299 300 /* wait for each to clear its bit */ 301 while (CPU_OVERLAP(&stopped_cpus, &map)) 302 cpu_spinwait(); 303 304 return 1; 305 } 306 307 /* 308 * All-CPU rendezvous. CPUs are signalled, all execute the setup function 309 * (if specified), rendezvous, execute the action function (if specified), 310 * rendezvous again, execute the teardown function (if specified), and then 311 * resume. 312 * 313 * Note that the supplied external functions _must_ be reentrant and aware 314 * that they are running in parallel and in an unknown lock context. 315 */ 316 void 317 smp_rendezvous_action(void) 318 { 319 struct thread *td; 320 void *local_func_arg; 321 void (*local_setup_func)(void*); 322 void (*local_action_func)(void*); 323 void (*local_teardown_func)(void*); 324 int generation; 325 #ifdef INVARIANTS 326 int owepreempt; 327 #endif 328 329 /* Ensure we have up-to-date values. */ 330 atomic_add_acq_int(&smp_rv_waiters[0], 1); 331 while (smp_rv_waiters[0] < smp_rv_ncpus) 332 cpu_spinwait(); 333 334 /* Fetch rendezvous parameters after acquire barrier. */ 335 local_func_arg = smp_rv_func_arg; 336 local_setup_func = smp_rv_setup_func; 337 local_action_func = smp_rv_action_func; 338 local_teardown_func = smp_rv_teardown_func; 339 generation = smp_rv_generation; 340 341 /* 342 * Use a nested critical section to prevent any preemptions 343 * from occurring during a rendezvous action routine. 344 * Specifically, if a rendezvous handler is invoked via an IPI 345 * and the interrupted thread was in the critical_exit() 346 * function after setting td_critnest to 0 but before 347 * performing a deferred preemption, this routine can be 348 * invoked with td_critnest set to 0 and td_owepreempt true. 349 * In that case, a critical_exit() during the rendezvous 350 * action would trigger a preemption which is not permitted in 351 * a rendezvous action. To fix this, wrap all of the 352 * rendezvous action handlers in a critical section. We 353 * cannot use a regular critical section however as having 354 * critical_exit() preempt from this routine would also be 355 * problematic (the preemption must not occur before the IPI 356 * has been acknowledged via an EOI). Instead, we 357 * intentionally ignore td_owepreempt when leaving the 358 * critical section. This should be harmless because we do 359 * not permit rendezvous action routines to schedule threads, 360 * and thus td_owepreempt should never transition from 0 to 1 361 * during this routine. 362 */ 363 td = curthread; 364 td->td_critnest++; 365 #ifdef INVARIANTS 366 owepreempt = td->td_owepreempt; 367 #endif 368 369 /* 370 * If requested, run a setup function before the main action 371 * function. Ensure all CPUs have completed the setup 372 * function before moving on to the action function. 373 */ 374 if (local_setup_func != smp_no_rendevous_barrier) { 375 if (smp_rv_setup_func != NULL) 376 smp_rv_setup_func(smp_rv_func_arg); 377 atomic_add_int(&smp_rv_waiters[1], 1); 378 while (smp_rv_waiters[1] < smp_rv_ncpus) 379 cpu_spinwait(); 380 } 381 382 if (local_action_func != NULL) 383 local_action_func(local_func_arg); 384 385 /* 386 * Signal that the main action has been completed. If a 387 * full exit rendezvous is requested, then all CPUs will 388 * wait here until all CPUs have finished the main action. 389 * 390 * Note that the write by the last CPU to finish the action 391 * may become visible to different CPUs at different times. 392 * As a result, the CPU that initiated the rendezvous may 393 * exit the rendezvous and drop the lock allowing another 394 * rendezvous to be initiated on the same CPU or a different 395 * CPU. In that case the exit sentinel may be cleared before 396 * all CPUs have noticed causing those CPUs to hang forever. 397 * Workaround this by using a generation count to notice when 398 * this race occurs and to exit the rendezvous in that case. 399 */ 400 MPASS(generation == smp_rv_generation); 401 atomic_add_int(&smp_rv_waiters[2], 1); 402 if (local_teardown_func != smp_no_rendevous_barrier) { 403 while (smp_rv_waiters[2] < smp_rv_ncpus && 404 generation == smp_rv_generation) 405 cpu_spinwait(); 406 407 if (local_teardown_func != NULL) 408 local_teardown_func(local_func_arg); 409 } 410 411 td->td_critnest--; 412 KASSERT(owepreempt == td->td_owepreempt, 413 ("rendezvous action changed td_owepreempt")); 414 } 415 416 void 417 smp_rendezvous_cpus(cpuset_t map, 418 void (* setup_func)(void *), 419 void (* action_func)(void *), 420 void (* teardown_func)(void *), 421 void *arg) 422 { 423 int curcpumap, i, ncpus = 0; 424 425 if (!smp_started) { 426 if (setup_func != NULL) 427 setup_func(arg); 428 if (action_func != NULL) 429 action_func(arg); 430 if (teardown_func != NULL) 431 teardown_func(arg); 432 return; 433 } 434 435 CPU_FOREACH(i) { 436 if (CPU_ISSET(i, &map)) 437 ncpus++; 438 } 439 if (ncpus == 0) 440 panic("ncpus is 0 with non-zero map"); 441 442 mtx_lock_spin(&smp_ipi_mtx); 443 444 atomic_add_acq_int(&smp_rv_generation, 1); 445 446 /* Pass rendezvous parameters via global variables. */ 447 smp_rv_ncpus = ncpus; 448 smp_rv_setup_func = setup_func; 449 smp_rv_action_func = action_func; 450 smp_rv_teardown_func = teardown_func; 451 smp_rv_func_arg = arg; 452 smp_rv_waiters[1] = 0; 453 smp_rv_waiters[2] = 0; 454 atomic_store_rel_int(&smp_rv_waiters[0], 0); 455 456 /* 457 * Signal other processors, which will enter the IPI with 458 * interrupts off. 459 */ 460 curcpumap = CPU_ISSET(curcpu, &map); 461 CPU_CLR(curcpu, &map); 462 ipi_selected(map, IPI_RENDEZVOUS); 463 464 /* Check if the current CPU is in the map */ 465 if (curcpumap != 0) 466 smp_rendezvous_action(); 467 468 /* 469 * If the caller did not request an exit barrier to be enforced 470 * on each CPU, ensure that this CPU waits for all the other 471 * CPUs to finish the rendezvous. 472 */ 473 if (teardown_func == smp_no_rendevous_barrier) 474 while (atomic_load_acq_int(&smp_rv_waiters[2]) < ncpus) 475 cpu_spinwait(); 476 477 mtx_unlock_spin(&smp_ipi_mtx); 478 } 479 480 void 481 smp_rendezvous(void (* setup_func)(void *), 482 void (* action_func)(void *), 483 void (* teardown_func)(void *), 484 void *arg) 485 { 486 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); 487 } 488 489 static struct cpu_group group[MAXCPU]; 490 491 struct cpu_group * 492 smp_topo(void) 493 { 494 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 495 struct cpu_group *top; 496 497 /* 498 * Check for a fake topology request for debugging purposes. 499 */ 500 switch (smp_topology) { 501 case 1: 502 /* Dual core with no sharing. */ 503 top = smp_topo_1level(CG_SHARE_NONE, 2, 0); 504 break; 505 case 2: 506 /* No topology, all cpus are equal. */ 507 top = smp_topo_none(); 508 break; 509 case 3: 510 /* Dual core with shared L2. */ 511 top = smp_topo_1level(CG_SHARE_L2, 2, 0); 512 break; 513 case 4: 514 /* quad core, shared l3 among each package, private l2. */ 515 top = smp_topo_1level(CG_SHARE_L3, 4, 0); 516 break; 517 case 5: 518 /* quad core, 2 dualcore parts on each package share l2. */ 519 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); 520 break; 521 case 6: 522 /* Single-core 2xHTT */ 523 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); 524 break; 525 case 7: 526 /* quad core with a shared l3, 8 threads sharing L2. */ 527 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, 528 CG_FLAG_SMT); 529 break; 530 default: 531 /* Default, ask the system what it wants. */ 532 top = cpu_topo(); 533 break; 534 } 535 /* 536 * Verify the returned topology. 537 */ 538 if (top->cg_count != mp_ncpus) 539 panic("Built bad topology at %p. CPU count %d != %d", 540 top, top->cg_count, mp_ncpus); 541 if (CPU_CMP(&top->cg_mask, &all_cpus)) 542 panic("Built bad topology at %p. CPU mask (%s) != (%s)", 543 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), 544 cpusetobj_strprint(cpusetbuf2, &all_cpus)); 545 return (top); 546 } 547 548 struct cpu_group * 549 smp_topo_none(void) 550 { 551 struct cpu_group *top; 552 553 top = &group[0]; 554 top->cg_parent = NULL; 555 top->cg_child = NULL; 556 top->cg_mask = all_cpus; 557 top->cg_count = mp_ncpus; 558 top->cg_children = 0; 559 top->cg_level = CG_SHARE_NONE; 560 top->cg_flags = 0; 561 562 return (top); 563 } 564 565 static int 566 smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, 567 int count, int flags, int start) 568 { 569 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 570 cpuset_t mask; 571 int i; 572 573 CPU_ZERO(&mask); 574 for (i = 0; i < count; i++, start++) 575 CPU_SET(start, &mask); 576 child->cg_parent = parent; 577 child->cg_child = NULL; 578 child->cg_children = 0; 579 child->cg_level = share; 580 child->cg_count = count; 581 child->cg_flags = flags; 582 child->cg_mask = mask; 583 parent->cg_children++; 584 for (; parent != NULL; parent = parent->cg_parent) { 585 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) 586 panic("Duplicate children in %p. mask (%s) child (%s)", 587 parent, 588 cpusetobj_strprint(cpusetbuf, &parent->cg_mask), 589 cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); 590 CPU_OR(&parent->cg_mask, &child->cg_mask); 591 parent->cg_count += child->cg_count; 592 } 593 594 return (start); 595 } 596 597 struct cpu_group * 598 smp_topo_1level(int share, int count, int flags) 599 { 600 struct cpu_group *child; 601 struct cpu_group *top; 602 int packages; 603 int cpu; 604 int i; 605 606 cpu = 0; 607 top = &group[0]; 608 packages = mp_ncpus / count; 609 top->cg_child = child = &group[1]; 610 top->cg_level = CG_SHARE_NONE; 611 for (i = 0; i < packages; i++, child++) 612 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); 613 return (top); 614 } 615 616 struct cpu_group * 617 smp_topo_2level(int l2share, int l2count, int l1share, int l1count, 618 int l1flags) 619 { 620 struct cpu_group *top; 621 struct cpu_group *l1g; 622 struct cpu_group *l2g; 623 int cpu; 624 int i; 625 int j; 626 627 cpu = 0; 628 top = &group[0]; 629 l2g = &group[1]; 630 top->cg_child = l2g; 631 top->cg_level = CG_SHARE_NONE; 632 top->cg_children = mp_ncpus / (l2count * l1count); 633 l1g = l2g + top->cg_children; 634 for (i = 0; i < top->cg_children; i++, l2g++) { 635 l2g->cg_parent = top; 636 l2g->cg_child = l1g; 637 l2g->cg_level = l2share; 638 for (j = 0; j < l2count; j++, l1g++) 639 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, 640 l1flags, cpu); 641 } 642 return (top); 643 } 644 645 646 struct cpu_group * 647 smp_topo_find(struct cpu_group *top, int cpu) 648 { 649 struct cpu_group *cg; 650 cpuset_t mask; 651 int children; 652 int i; 653 654 CPU_SETOF(cpu, &mask); 655 cg = top; 656 for (;;) { 657 if (!CPU_OVERLAP(&cg->cg_mask, &mask)) 658 return (NULL); 659 if (cg->cg_children == 0) 660 return (cg); 661 children = cg->cg_children; 662 for (i = 0, cg = cg->cg_child; i < children; cg++, i++) 663 if (CPU_OVERLAP(&cg->cg_mask, &mask)) 664 break; 665 } 666 return (NULL); 667 } 668 #else /* !SMP */ 669 670 void 671 smp_rendezvous_cpus(cpuset_t map, 672 void (*setup_func)(void *), 673 void (*action_func)(void *), 674 void (*teardown_func)(void *), 675 void *arg) 676 { 677 if (setup_func != NULL) 678 setup_func(arg); 679 if (action_func != NULL) 680 action_func(arg); 681 if (teardown_func != NULL) 682 teardown_func(arg); 683 } 684 685 void 686 smp_rendezvous(void (*setup_func)(void *), 687 void (*action_func)(void *), 688 void (*teardown_func)(void *), 689 void *arg) 690 { 691 692 if (setup_func != NULL) 693 setup_func(arg); 694 if (action_func != NULL) 695 action_func(arg); 696 if (teardown_func != NULL) 697 teardown_func(arg); 698 } 699 700 /* 701 * Provide dummy SMP support for UP kernels. Modules that need to use SMP 702 * APIs will still work using this dummy support. 703 */ 704 static void 705 mp_setvariables_for_up(void *dummy) 706 { 707 mp_ncpus = 1; 708 mp_maxid = PCPU_GET(cpuid); 709 CPU_SETOF(mp_maxid, &all_cpus); 710 KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero")); 711 } 712 SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST, 713 mp_setvariables_for_up, NULL); 714 #endif /* SMP */ 715 716 void 717 smp_no_rendevous_barrier(void *dummy) 718 { 719 #ifdef SMP 720 KASSERT((!smp_started),("smp_no_rendevous called and smp is started")); 721 #endif 722 } 723