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 volatile cpuset_t suspended_cpus; 59 cpuset_t hlt_cpus_mask; 60 cpuset_t logical_cpus_mask; 61 62 void (*cpustop_restartfunc)(void); 63 #endif 64 /* This is used in modules that need to work in both SMP and UP. */ 65 cpuset_t all_cpus; 66 67 int mp_ncpus; 68 /* export this for libkvm consumers. */ 69 int mp_maxcpus = MAXCPU; 70 71 volatile int smp_started; 72 u_int mp_maxid; 73 74 static SYSCTL_NODE(_kern, OID_AUTO, smp, CTLFLAG_RD|CTLFLAG_CAPRD, NULL, 75 "Kernel SMP"); 76 77 SYSCTL_INT(_kern_smp, OID_AUTO, maxid, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxid, 0, 78 "Max CPU ID."); 79 80 SYSCTL_INT(_kern_smp, OID_AUTO, maxcpus, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxcpus, 81 0, "Max number of CPUs that the system was compiled for."); 82 83 int smp_active = 0; /* are the APs allowed to run? */ 84 SYSCTL_INT(_kern_smp, OID_AUTO, active, CTLFLAG_RW, &smp_active, 0, 85 "Number of Auxillary Processors (APs) that were successfully started"); 86 87 int smp_disabled = 0; /* has smp been disabled? */ 88 SYSCTL_INT(_kern_smp, OID_AUTO, disabled, CTLFLAG_RDTUN|CTLFLAG_CAPRD, 89 &smp_disabled, 0, "SMP has been disabled from the loader"); 90 TUNABLE_INT("kern.smp.disabled", &smp_disabled); 91 92 int smp_cpus = 1; /* how many cpu's running */ 93 SYSCTL_INT(_kern_smp, OID_AUTO, cpus, CTLFLAG_RD|CTLFLAG_CAPRD, &smp_cpus, 0, 94 "Number of CPUs online"); 95 96 int smp_topology = 0; /* Which topology we're using. */ 97 SYSCTL_INT(_kern_smp, OID_AUTO, topology, CTLFLAG_RD, &smp_topology, 0, 98 "Topology override setting; 0 is default provided by hardware."); 99 TUNABLE_INT("kern.smp.topology", &smp_topology); 100 101 #ifdef SMP 102 /* Enable forwarding of a signal to a process running on a different CPU */ 103 static int forward_signal_enabled = 1; 104 SYSCTL_INT(_kern_smp, OID_AUTO, forward_signal_enabled, CTLFLAG_RW, 105 &forward_signal_enabled, 0, 106 "Forwarding of a signal to a process on a different CPU"); 107 108 /* Variables needed for SMP rendezvous. */ 109 static volatile int smp_rv_ncpus; 110 static void (*volatile smp_rv_setup_func)(void *arg); 111 static void (*volatile smp_rv_action_func)(void *arg); 112 static void (*volatile smp_rv_teardown_func)(void *arg); 113 static void *volatile smp_rv_func_arg; 114 static volatile int smp_rv_waiters[4]; 115 116 /* 117 * Shared mutex to restrict busywaits between smp_rendezvous() and 118 * smp(_targeted)_tlb_shootdown(). A deadlock occurs if both of these 119 * functions trigger at once and cause multiple CPUs to busywait with 120 * interrupts disabled. 121 */ 122 struct mtx smp_ipi_mtx; 123 124 /* 125 * Let the MD SMP code initialize mp_maxid very early if it can. 126 */ 127 static void 128 mp_setmaxid(void *dummy) 129 { 130 cpu_mp_setmaxid(); 131 } 132 SYSINIT(cpu_mp_setmaxid, SI_SUB_TUNABLES, SI_ORDER_FIRST, mp_setmaxid, NULL); 133 134 /* 135 * Call the MD SMP initialization code. 136 */ 137 static void 138 mp_start(void *dummy) 139 { 140 141 mtx_init(&smp_ipi_mtx, "smp rendezvous", NULL, MTX_SPIN); 142 143 /* Probe for MP hardware. */ 144 if (smp_disabled != 0 || cpu_mp_probe() == 0) { 145 mp_ncpus = 1; 146 CPU_SETOF(PCPU_GET(cpuid), &all_cpus); 147 return; 148 } 149 150 cpu_mp_start(); 151 printf("FreeBSD/SMP: Multiprocessor System Detected: %d CPUs\n", 152 mp_ncpus); 153 cpu_mp_announce(); 154 } 155 SYSINIT(cpu_mp, SI_SUB_CPU, SI_ORDER_THIRD, mp_start, NULL); 156 157 void 158 forward_signal(struct thread *td) 159 { 160 int id; 161 162 /* 163 * signotify() has already set TDF_ASTPENDING and TDF_NEEDSIGCHECK on 164 * this thread, so all we need to do is poke it if it is currently 165 * executing so that it executes ast(). 166 */ 167 THREAD_LOCK_ASSERT(td, MA_OWNED); 168 KASSERT(TD_IS_RUNNING(td), 169 ("forward_signal: thread is not TDS_RUNNING")); 170 171 CTR1(KTR_SMP, "forward_signal(%p)", td->td_proc); 172 173 if (!smp_started || cold || panicstr) 174 return; 175 if (!forward_signal_enabled) 176 return; 177 178 /* No need to IPI ourself. */ 179 if (td == curthread) 180 return; 181 182 id = td->td_oncpu; 183 if (id == NOCPU) 184 return; 185 ipi_cpu(id, IPI_AST); 186 } 187 188 /* 189 * When called the executing CPU will send an IPI to all other CPUs 190 * requesting that they halt execution. 191 * 192 * Usually (but not necessarily) called with 'other_cpus' as its arg. 193 * 194 * - Signals all CPUs in map to stop. 195 * - Waits for each to stop. 196 * 197 * Returns: 198 * -1: error 199 * 0: NA 200 * 1: ok 201 * 202 */ 203 static int 204 generic_stop_cpus(cpuset_t map, u_int type) 205 { 206 #ifdef KTR 207 char cpusetbuf[CPUSETBUFSIZ]; 208 #endif 209 static volatile u_int stopping_cpu = NOCPU; 210 int i; 211 volatile cpuset_t *cpus; 212 213 KASSERT( 214 #if defined(__amd64__) || defined(__i386__) 215 type == IPI_STOP || type == IPI_STOP_HARD || type == IPI_SUSPEND, 216 #else 217 type == IPI_STOP || type == IPI_STOP_HARD, 218 #endif 219 ("%s: invalid stop type", __func__)); 220 221 if (!smp_started) 222 return (0); 223 224 CTR2(KTR_SMP, "stop_cpus(%s) with %u type", 225 cpusetobj_strprint(cpusetbuf, &map), type); 226 227 if (stopping_cpu != PCPU_GET(cpuid)) 228 while (atomic_cmpset_int(&stopping_cpu, NOCPU, 229 PCPU_GET(cpuid)) == 0) 230 while (stopping_cpu != NOCPU) 231 cpu_spinwait(); /* spin */ 232 233 /* send the stop IPI to all CPUs in map */ 234 ipi_selected(map, type); 235 236 #if defined(__amd64__) || defined(__i386__) 237 if (type == IPI_SUSPEND) 238 cpus = &suspended_cpus; 239 else 240 #endif 241 cpus = &stopped_cpus; 242 243 i = 0; 244 while (!CPU_SUBSET(cpus, &map)) { 245 /* spin */ 246 cpu_spinwait(); 247 i++; 248 if (i == 100000000) { 249 printf("timeout stopping cpus\n"); 250 break; 251 } 252 } 253 254 stopping_cpu = NOCPU; 255 return (1); 256 } 257 258 int 259 stop_cpus(cpuset_t map) 260 { 261 262 return (generic_stop_cpus(map, IPI_STOP)); 263 } 264 265 int 266 stop_cpus_hard(cpuset_t map) 267 { 268 269 return (generic_stop_cpus(map, IPI_STOP_HARD)); 270 } 271 272 #if defined(__amd64__) || defined(__i386__) 273 int 274 suspend_cpus(cpuset_t map) 275 { 276 277 return (generic_stop_cpus(map, IPI_SUSPEND)); 278 } 279 #endif 280 281 /* 282 * Called by a CPU to restart stopped CPUs. 283 * 284 * Usually (but not necessarily) called with 'stopped_cpus' as its arg. 285 * 286 * - Signals all CPUs in map to restart. 287 * - Waits for each to restart. 288 * 289 * Returns: 290 * -1: error 291 * 0: NA 292 * 1: ok 293 */ 294 int 295 restart_cpus(cpuset_t map) 296 { 297 #ifdef KTR 298 char cpusetbuf[CPUSETBUFSIZ]; 299 #endif 300 301 if (!smp_started) 302 return 0; 303 304 CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); 305 306 /* signal other cpus to restart */ 307 CPU_COPY_STORE_REL(&map, &started_cpus); 308 309 /* wait for each to clear its bit */ 310 while (CPU_OVERLAP(&stopped_cpus, &map)) 311 cpu_spinwait(); 312 313 return 1; 314 } 315 316 /* 317 * All-CPU rendezvous. CPUs are signalled, all execute the setup function 318 * (if specified), rendezvous, execute the action function (if specified), 319 * rendezvous again, execute the teardown function (if specified), and then 320 * resume. 321 * 322 * Note that the supplied external functions _must_ be reentrant and aware 323 * that they are running in parallel and in an unknown lock context. 324 */ 325 void 326 smp_rendezvous_action(void) 327 { 328 struct thread *td; 329 void *local_func_arg; 330 void (*local_setup_func)(void*); 331 void (*local_action_func)(void*); 332 void (*local_teardown_func)(void*); 333 #ifdef INVARIANTS 334 int owepreempt; 335 #endif 336 337 /* Ensure we have up-to-date values. */ 338 atomic_add_acq_int(&smp_rv_waiters[0], 1); 339 while (smp_rv_waiters[0] < smp_rv_ncpus) 340 cpu_spinwait(); 341 342 /* Fetch rendezvous parameters after acquire barrier. */ 343 local_func_arg = smp_rv_func_arg; 344 local_setup_func = smp_rv_setup_func; 345 local_action_func = smp_rv_action_func; 346 local_teardown_func = smp_rv_teardown_func; 347 348 /* 349 * Use a nested critical section to prevent any preemptions 350 * from occurring during a rendezvous action routine. 351 * Specifically, if a rendezvous handler is invoked via an IPI 352 * and the interrupted thread was in the critical_exit() 353 * function after setting td_critnest to 0 but before 354 * performing a deferred preemption, this routine can be 355 * invoked with td_critnest set to 0 and td_owepreempt true. 356 * In that case, a critical_exit() during the rendezvous 357 * action would trigger a preemption which is not permitted in 358 * a rendezvous action. To fix this, wrap all of the 359 * rendezvous action handlers in a critical section. We 360 * cannot use a regular critical section however as having 361 * critical_exit() preempt from this routine would also be 362 * problematic (the preemption must not occur before the IPI 363 * has been acknowledged via an EOI). Instead, we 364 * intentionally ignore td_owepreempt when leaving the 365 * critical section. This should be harmless because we do 366 * not permit rendezvous action routines to schedule threads, 367 * and thus td_owepreempt should never transition from 0 to 1 368 * during this routine. 369 */ 370 td = curthread; 371 td->td_critnest++; 372 #ifdef INVARIANTS 373 owepreempt = td->td_owepreempt; 374 #endif 375 376 /* 377 * If requested, run a setup function before the main action 378 * function. Ensure all CPUs have completed the setup 379 * function before moving on to the action function. 380 */ 381 if (local_setup_func != smp_no_rendevous_barrier) { 382 if (smp_rv_setup_func != NULL) 383 smp_rv_setup_func(smp_rv_func_arg); 384 atomic_add_int(&smp_rv_waiters[1], 1); 385 while (smp_rv_waiters[1] < smp_rv_ncpus) 386 cpu_spinwait(); 387 } 388 389 if (local_action_func != NULL) 390 local_action_func(local_func_arg); 391 392 if (local_teardown_func != smp_no_rendevous_barrier) { 393 /* 394 * Signal that the main action has been completed. If a 395 * full exit rendezvous is requested, then all CPUs will 396 * wait here until all CPUs have finished the main action. 397 */ 398 atomic_add_int(&smp_rv_waiters[2], 1); 399 while (smp_rv_waiters[2] < smp_rv_ncpus) 400 cpu_spinwait(); 401 402 if (local_teardown_func != NULL) 403 local_teardown_func(local_func_arg); 404 } 405 406 /* 407 * Signal that the rendezvous is fully completed by this CPU. 408 * This means that no member of smp_rv_* pseudo-structure will be 409 * accessed by this target CPU after this point; in particular, 410 * memory pointed by smp_rv_func_arg. 411 */ 412 atomic_add_int(&smp_rv_waiters[3], 1); 413 414 td->td_critnest--; 415 KASSERT(owepreempt == td->td_owepreempt, 416 ("rendezvous action changed td_owepreempt")); 417 } 418 419 void 420 smp_rendezvous_cpus(cpuset_t map, 421 void (* setup_func)(void *), 422 void (* action_func)(void *), 423 void (* teardown_func)(void *), 424 void *arg) 425 { 426 int curcpumap, i, ncpus = 0; 427 428 /* Look comments in the !SMP case. */ 429 if (!smp_started) { 430 spinlock_enter(); 431 if (setup_func != NULL) 432 setup_func(arg); 433 if (action_func != NULL) 434 action_func(arg); 435 if (teardown_func != NULL) 436 teardown_func(arg); 437 spinlock_exit(); 438 return; 439 } 440 441 CPU_FOREACH(i) { 442 if (CPU_ISSET(i, &map)) 443 ncpus++; 444 } 445 if (ncpus == 0) 446 panic("ncpus is 0 with non-zero map"); 447 448 mtx_lock_spin(&smp_ipi_mtx); 449 450 /* Pass rendezvous parameters via global variables. */ 451 smp_rv_ncpus = ncpus; 452 smp_rv_setup_func = setup_func; 453 smp_rv_action_func = action_func; 454 smp_rv_teardown_func = teardown_func; 455 smp_rv_func_arg = arg; 456 smp_rv_waiters[1] = 0; 457 smp_rv_waiters[2] = 0; 458 smp_rv_waiters[3] = 0; 459 atomic_store_rel_int(&smp_rv_waiters[0], 0); 460 461 /* 462 * Signal other processors, which will enter the IPI with 463 * interrupts off. 464 */ 465 curcpumap = CPU_ISSET(curcpu, &map); 466 CPU_CLR(curcpu, &map); 467 ipi_selected(map, IPI_RENDEZVOUS); 468 469 /* Check if the current CPU is in the map */ 470 if (curcpumap != 0) 471 smp_rendezvous_action(); 472 473 /* 474 * Ensure that the master CPU waits for all the other 475 * CPUs to finish the rendezvous, so that smp_rv_* 476 * pseudo-structure and the arg are guaranteed to not 477 * be in use. 478 */ 479 while (atomic_load_acq_int(&smp_rv_waiters[3]) < ncpus) 480 cpu_spinwait(); 481 482 mtx_unlock_spin(&smp_ipi_mtx); 483 } 484 485 void 486 smp_rendezvous(void (* setup_func)(void *), 487 void (* action_func)(void *), 488 void (* teardown_func)(void *), 489 void *arg) 490 { 491 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); 492 } 493 494 static struct cpu_group group[MAXCPU]; 495 496 struct cpu_group * 497 smp_topo(void) 498 { 499 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 500 struct cpu_group *top; 501 502 /* 503 * Check for a fake topology request for debugging purposes. 504 */ 505 switch (smp_topology) { 506 case 1: 507 /* Dual core with no sharing. */ 508 top = smp_topo_1level(CG_SHARE_NONE, 2, 0); 509 break; 510 case 2: 511 /* No topology, all cpus are equal. */ 512 top = smp_topo_none(); 513 break; 514 case 3: 515 /* Dual core with shared L2. */ 516 top = smp_topo_1level(CG_SHARE_L2, 2, 0); 517 break; 518 case 4: 519 /* quad core, shared l3 among each package, private l2. */ 520 top = smp_topo_1level(CG_SHARE_L3, 4, 0); 521 break; 522 case 5: 523 /* quad core, 2 dualcore parts on each package share l2. */ 524 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); 525 break; 526 case 6: 527 /* Single-core 2xHTT */ 528 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); 529 break; 530 case 7: 531 /* quad core with a shared l3, 8 threads sharing L2. */ 532 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, 533 CG_FLAG_SMT); 534 break; 535 default: 536 /* Default, ask the system what it wants. */ 537 top = cpu_topo(); 538 break; 539 } 540 /* 541 * Verify the returned topology. 542 */ 543 if (top->cg_count != mp_ncpus) 544 panic("Built bad topology at %p. CPU count %d != %d", 545 top, top->cg_count, mp_ncpus); 546 if (CPU_CMP(&top->cg_mask, &all_cpus)) 547 panic("Built bad topology at %p. CPU mask (%s) != (%s)", 548 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), 549 cpusetobj_strprint(cpusetbuf2, &all_cpus)); 550 return (top); 551 } 552 553 struct cpu_group * 554 smp_topo_none(void) 555 { 556 struct cpu_group *top; 557 558 top = &group[0]; 559 top->cg_parent = NULL; 560 top->cg_child = NULL; 561 top->cg_mask = all_cpus; 562 top->cg_count = mp_ncpus; 563 top->cg_children = 0; 564 top->cg_level = CG_SHARE_NONE; 565 top->cg_flags = 0; 566 567 return (top); 568 } 569 570 static int 571 smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, 572 int count, int flags, int start) 573 { 574 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 575 cpuset_t mask; 576 int i; 577 578 CPU_ZERO(&mask); 579 for (i = 0; i < count; i++, start++) 580 CPU_SET(start, &mask); 581 child->cg_parent = parent; 582 child->cg_child = NULL; 583 child->cg_children = 0; 584 child->cg_level = share; 585 child->cg_count = count; 586 child->cg_flags = flags; 587 child->cg_mask = mask; 588 parent->cg_children++; 589 for (; parent != NULL; parent = parent->cg_parent) { 590 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) 591 panic("Duplicate children in %p. mask (%s) child (%s)", 592 parent, 593 cpusetobj_strprint(cpusetbuf, &parent->cg_mask), 594 cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); 595 CPU_OR(&parent->cg_mask, &child->cg_mask); 596 parent->cg_count += child->cg_count; 597 } 598 599 return (start); 600 } 601 602 struct cpu_group * 603 smp_topo_1level(int share, int count, int flags) 604 { 605 struct cpu_group *child; 606 struct cpu_group *top; 607 int packages; 608 int cpu; 609 int i; 610 611 cpu = 0; 612 top = &group[0]; 613 packages = mp_ncpus / count; 614 top->cg_child = child = &group[1]; 615 top->cg_level = CG_SHARE_NONE; 616 for (i = 0; i < packages; i++, child++) 617 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); 618 return (top); 619 } 620 621 struct cpu_group * 622 smp_topo_2level(int l2share, int l2count, int l1share, int l1count, 623 int l1flags) 624 { 625 struct cpu_group *top; 626 struct cpu_group *l1g; 627 struct cpu_group *l2g; 628 int cpu; 629 int i; 630 int j; 631 632 cpu = 0; 633 top = &group[0]; 634 l2g = &group[1]; 635 top->cg_child = l2g; 636 top->cg_level = CG_SHARE_NONE; 637 top->cg_children = mp_ncpus / (l2count * l1count); 638 l1g = l2g + top->cg_children; 639 for (i = 0; i < top->cg_children; i++, l2g++) { 640 l2g->cg_parent = top; 641 l2g->cg_child = l1g; 642 l2g->cg_level = l2share; 643 for (j = 0; j < l2count; j++, l1g++) 644 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, 645 l1flags, cpu); 646 } 647 return (top); 648 } 649 650 651 struct cpu_group * 652 smp_topo_find(struct cpu_group *top, int cpu) 653 { 654 struct cpu_group *cg; 655 cpuset_t mask; 656 int children; 657 int i; 658 659 CPU_SETOF(cpu, &mask); 660 cg = top; 661 for (;;) { 662 if (!CPU_OVERLAP(&cg->cg_mask, &mask)) 663 return (NULL); 664 if (cg->cg_children == 0) 665 return (cg); 666 children = cg->cg_children; 667 for (i = 0, cg = cg->cg_child; i < children; cg++, i++) 668 if (CPU_OVERLAP(&cg->cg_mask, &mask)) 669 break; 670 } 671 return (NULL); 672 } 673 #else /* !SMP */ 674 675 void 676 smp_rendezvous_cpus(cpuset_t map, 677 void (*setup_func)(void *), 678 void (*action_func)(void *), 679 void (*teardown_func)(void *), 680 void *arg) 681 { 682 /* 683 * In the !SMP case we just need to ensure the same initial conditions 684 * as the SMP case. 685 */ 686 spinlock_enter(); 687 if (setup_func != NULL) 688 setup_func(arg); 689 if (action_func != NULL) 690 action_func(arg); 691 if (teardown_func != NULL) 692 teardown_func(arg); 693 spinlock_exit(); 694 } 695 696 void 697 smp_rendezvous(void (*setup_func)(void *), 698 void (*action_func)(void *), 699 void (*teardown_func)(void *), 700 void *arg) 701 { 702 703 /* Look comments in the smp_rendezvous_cpus() case. */ 704 spinlock_enter(); 705 if (setup_func != NULL) 706 setup_func(arg); 707 if (action_func != NULL) 708 action_func(arg); 709 if (teardown_func != NULL) 710 teardown_func(arg); 711 spinlock_exit(); 712 } 713 714 /* 715 * Provide dummy SMP support for UP kernels. Modules that need to use SMP 716 * APIs will still work using this dummy support. 717 */ 718 static void 719 mp_setvariables_for_up(void *dummy) 720 { 721 mp_ncpus = 1; 722 mp_maxid = PCPU_GET(cpuid); 723 CPU_SETOF(mp_maxid, &all_cpus); 724 KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero")); 725 } 726 SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST, 727 mp_setvariables_for_up, NULL); 728 #endif /* SMP */ 729 730 void 731 smp_no_rendevous_barrier(void *dummy) 732 { 733 #ifdef SMP 734 KASSERT((!smp_started),("smp_no_rendevous called and smp is started")); 735 #endif 736 } 737