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 /* Look comments in the !SMP case. */ 419 if (!smp_started) { 420 spinlock_enter(); 421 if (setup_func != NULL) 422 setup_func(arg); 423 if (action_func != NULL) 424 action_func(arg); 425 if (teardown_func != NULL) 426 teardown_func(arg); 427 spinlock_exit(); 428 return; 429 } 430 431 CPU_FOREACH(i) { 432 if (CPU_ISSET(i, &map)) 433 ncpus++; 434 } 435 if (ncpus == 0) 436 panic("ncpus is 0 with non-zero map"); 437 438 mtx_lock_spin(&smp_ipi_mtx); 439 440 /* Pass rendezvous parameters via global variables. */ 441 smp_rv_ncpus = ncpus; 442 smp_rv_setup_func = setup_func; 443 smp_rv_action_func = action_func; 444 smp_rv_teardown_func = teardown_func; 445 smp_rv_func_arg = arg; 446 smp_rv_waiters[1] = 0; 447 smp_rv_waiters[2] = 0; 448 smp_rv_waiters[3] = 0; 449 atomic_store_rel_int(&smp_rv_waiters[0], 0); 450 451 /* 452 * Signal other processors, which will enter the IPI with 453 * interrupts off. 454 */ 455 curcpumap = CPU_ISSET(curcpu, &map); 456 CPU_CLR(curcpu, &map); 457 ipi_selected(map, IPI_RENDEZVOUS); 458 459 /* Check if the current CPU is in the map */ 460 if (curcpumap != 0) 461 smp_rendezvous_action(); 462 463 /* 464 * Ensure that the master CPU waits for all the other 465 * CPUs to finish the rendezvous, so that smp_rv_* 466 * pseudo-structure and the arg are guaranteed to not 467 * be in use. 468 */ 469 while (atomic_load_acq_int(&smp_rv_waiters[3]) < ncpus) 470 cpu_spinwait(); 471 472 mtx_unlock_spin(&smp_ipi_mtx); 473 } 474 475 void 476 smp_rendezvous(void (* setup_func)(void *), 477 void (* action_func)(void *), 478 void (* teardown_func)(void *), 479 void *arg) 480 { 481 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); 482 } 483 484 static struct cpu_group group[MAXCPU]; 485 486 struct cpu_group * 487 smp_topo(void) 488 { 489 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 490 struct cpu_group *top; 491 492 /* 493 * Check for a fake topology request for debugging purposes. 494 */ 495 switch (smp_topology) { 496 case 1: 497 /* Dual core with no sharing. */ 498 top = smp_topo_1level(CG_SHARE_NONE, 2, 0); 499 break; 500 case 2: 501 /* No topology, all cpus are equal. */ 502 top = smp_topo_none(); 503 break; 504 case 3: 505 /* Dual core with shared L2. */ 506 top = smp_topo_1level(CG_SHARE_L2, 2, 0); 507 break; 508 case 4: 509 /* quad core, shared l3 among each package, private l2. */ 510 top = smp_topo_1level(CG_SHARE_L3, 4, 0); 511 break; 512 case 5: 513 /* quad core, 2 dualcore parts on each package share l2. */ 514 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); 515 break; 516 case 6: 517 /* Single-core 2xHTT */ 518 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); 519 break; 520 case 7: 521 /* quad core with a shared l3, 8 threads sharing L2. */ 522 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, 523 CG_FLAG_SMT); 524 break; 525 default: 526 /* Default, ask the system what it wants. */ 527 top = cpu_topo(); 528 break; 529 } 530 /* 531 * Verify the returned topology. 532 */ 533 if (top->cg_count != mp_ncpus) 534 panic("Built bad topology at %p. CPU count %d != %d", 535 top, top->cg_count, mp_ncpus); 536 if (CPU_CMP(&top->cg_mask, &all_cpus)) 537 panic("Built bad topology at %p. CPU mask (%s) != (%s)", 538 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), 539 cpusetobj_strprint(cpusetbuf2, &all_cpus)); 540 return (top); 541 } 542 543 struct cpu_group * 544 smp_topo_none(void) 545 { 546 struct cpu_group *top; 547 548 top = &group[0]; 549 top->cg_parent = NULL; 550 top->cg_child = NULL; 551 top->cg_mask = all_cpus; 552 top->cg_count = mp_ncpus; 553 top->cg_children = 0; 554 top->cg_level = CG_SHARE_NONE; 555 top->cg_flags = 0; 556 557 return (top); 558 } 559 560 static int 561 smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, 562 int count, int flags, int start) 563 { 564 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 565 cpuset_t mask; 566 int i; 567 568 CPU_ZERO(&mask); 569 for (i = 0; i < count; i++, start++) 570 CPU_SET(start, &mask); 571 child->cg_parent = parent; 572 child->cg_child = NULL; 573 child->cg_children = 0; 574 child->cg_level = share; 575 child->cg_count = count; 576 child->cg_flags = flags; 577 child->cg_mask = mask; 578 parent->cg_children++; 579 for (; parent != NULL; parent = parent->cg_parent) { 580 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) 581 panic("Duplicate children in %p. mask (%s) child (%s)", 582 parent, 583 cpusetobj_strprint(cpusetbuf, &parent->cg_mask), 584 cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); 585 CPU_OR(&parent->cg_mask, &child->cg_mask); 586 parent->cg_count += child->cg_count; 587 } 588 589 return (start); 590 } 591 592 struct cpu_group * 593 smp_topo_1level(int share, int count, int flags) 594 { 595 struct cpu_group *child; 596 struct cpu_group *top; 597 int packages; 598 int cpu; 599 int i; 600 601 cpu = 0; 602 top = &group[0]; 603 packages = mp_ncpus / count; 604 top->cg_child = child = &group[1]; 605 top->cg_level = CG_SHARE_NONE; 606 for (i = 0; i < packages; i++, child++) 607 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); 608 return (top); 609 } 610 611 struct cpu_group * 612 smp_topo_2level(int l2share, int l2count, int l1share, int l1count, 613 int l1flags) 614 { 615 struct cpu_group *top; 616 struct cpu_group *l1g; 617 struct cpu_group *l2g; 618 int cpu; 619 int i; 620 int j; 621 622 cpu = 0; 623 top = &group[0]; 624 l2g = &group[1]; 625 top->cg_child = l2g; 626 top->cg_level = CG_SHARE_NONE; 627 top->cg_children = mp_ncpus / (l2count * l1count); 628 l1g = l2g + top->cg_children; 629 for (i = 0; i < top->cg_children; i++, l2g++) { 630 l2g->cg_parent = top; 631 l2g->cg_child = l1g; 632 l2g->cg_level = l2share; 633 for (j = 0; j < l2count; j++, l1g++) 634 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, 635 l1flags, cpu); 636 } 637 return (top); 638 } 639 640 641 struct cpu_group * 642 smp_topo_find(struct cpu_group *top, int cpu) 643 { 644 struct cpu_group *cg; 645 cpuset_t mask; 646 int children; 647 int i; 648 649 CPU_SETOF(cpu, &mask); 650 cg = top; 651 for (;;) { 652 if (!CPU_OVERLAP(&cg->cg_mask, &mask)) 653 return (NULL); 654 if (cg->cg_children == 0) 655 return (cg); 656 children = cg->cg_children; 657 for (i = 0, cg = cg->cg_child; i < children; cg++, i++) 658 if (CPU_OVERLAP(&cg->cg_mask, &mask)) 659 break; 660 } 661 return (NULL); 662 } 663 #else /* !SMP */ 664 665 void 666 smp_rendezvous_cpus(cpuset_t map, 667 void (*setup_func)(void *), 668 void (*action_func)(void *), 669 void (*teardown_func)(void *), 670 void *arg) 671 { 672 /* 673 * In the !SMP case we just need to ensure the same initial conditions 674 * as the SMP case. 675 */ 676 spinlock_enter(); 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 spinlock_exit(); 684 } 685 686 void 687 smp_rendezvous(void (*setup_func)(void *), 688 void (*action_func)(void *), 689 void (*teardown_func)(void *), 690 void *arg) 691 { 692 693 /* Look comments in the smp_rendezvous_cpus() case. */ 694 spinlock_enter(); 695 if (setup_func != NULL) 696 setup_func(arg); 697 if (action_func != NULL) 698 action_func(arg); 699 if (teardown_func != NULL) 700 teardown_func(arg); 701 spinlock_exit(); 702 } 703 704 /* 705 * Provide dummy SMP support for UP kernels. Modules that need to use SMP 706 * APIs will still work using this dummy support. 707 */ 708 static void 709 mp_setvariables_for_up(void *dummy) 710 { 711 mp_ncpus = 1; 712 mp_maxid = PCPU_GET(cpuid); 713 CPU_SETOF(mp_maxid, &all_cpus); 714 KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero")); 715 } 716 SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST, 717 mp_setvariables_for_up, NULL); 718 #endif /* SMP */ 719 720 void 721 smp_no_rendevous_barrier(void *dummy) 722 { 723 #ifdef SMP 724 KASSERT((!smp_started),("smp_no_rendevous called and smp is started")); 725 #endif 726 } 727