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 static SYSCTL_NODE(_kern, OID_AUTO, smp, CTLFLAG_RD|CTLFLAG_CAPRD, NULL, 74 "Kernel SMP"); 75 76 SYSCTL_INT(_kern_smp, OID_AUTO, maxid, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxid, 0, 77 "Max CPU ID."); 78 79 SYSCTL_INT(_kern_smp, OID_AUTO, maxcpus, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxcpus, 80 0, "Max number of CPUs that the system was compiled for."); 81 82 int smp_active = 0; /* are the APs allowed to run? */ 83 SYSCTL_INT(_kern_smp, OID_AUTO, active, CTLFLAG_RW, &smp_active, 0, 84 "Number of Auxillary Processors (APs) that were successfully started"); 85 86 int smp_disabled = 0; /* has smp been disabled? */ 87 SYSCTL_INT(_kern_smp, OID_AUTO, disabled, CTLFLAG_RDTUN|CTLFLAG_CAPRD, 88 &smp_disabled, 0, "SMP has been disabled from the loader"); 89 TUNABLE_INT("kern.smp.disabled", &smp_disabled); 90 91 int smp_cpus = 1; /* how many cpu's running */ 92 SYSCTL_INT(_kern_smp, OID_AUTO, cpus, CTLFLAG_RD|CTLFLAG_CAPRD, &smp_cpus, 0, 93 "Number of CPUs online"); 94 95 int smp_topology = 0; /* Which topology we're using. */ 96 SYSCTL_INT(_kern_smp, OID_AUTO, topology, CTLFLAG_RD, &smp_topology, 0, 97 "Topology override setting; 0 is default provided by hardware."); 98 TUNABLE_INT("kern.smp.topology", &smp_topology); 99 100 #ifdef SMP 101 /* Enable forwarding of a signal to a process running on a different CPU */ 102 static int forward_signal_enabled = 1; 103 SYSCTL_INT(_kern_smp, OID_AUTO, forward_signal_enabled, CTLFLAG_RW, 104 &forward_signal_enabled, 0, 105 "Forwarding of a signal to a process on a different CPU"); 106 107 /* Variables needed for SMP rendezvous. */ 108 static volatile int smp_rv_ncpus; 109 static void (*volatile smp_rv_setup_func)(void *arg); 110 static void (*volatile smp_rv_action_func)(void *arg); 111 static void (*volatile smp_rv_teardown_func)(void *arg); 112 static void *volatile smp_rv_func_arg; 113 static volatile int smp_rv_waiters[4]; 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 #ifdef INVARIANTS 325 int owepreempt; 326 #endif 327 328 /* Ensure we have up-to-date values. */ 329 atomic_add_acq_int(&smp_rv_waiters[0], 1); 330 while (smp_rv_waiters[0] < smp_rv_ncpus) 331 cpu_spinwait(); 332 333 /* Fetch rendezvous parameters after acquire barrier. */ 334 local_func_arg = smp_rv_func_arg; 335 local_setup_func = smp_rv_setup_func; 336 local_action_func = smp_rv_action_func; 337 local_teardown_func = smp_rv_teardown_func; 338 339 /* 340 * Use a nested critical section to prevent any preemptions 341 * from occurring during a rendezvous action routine. 342 * Specifically, if a rendezvous handler is invoked via an IPI 343 * and the interrupted thread was in the critical_exit() 344 * function after setting td_critnest to 0 but before 345 * performing a deferred preemption, this routine can be 346 * invoked with td_critnest set to 0 and td_owepreempt true. 347 * In that case, a critical_exit() during the rendezvous 348 * action would trigger a preemption which is not permitted in 349 * a rendezvous action. To fix this, wrap all of the 350 * rendezvous action handlers in a critical section. We 351 * cannot use a regular critical section however as having 352 * critical_exit() preempt from this routine would also be 353 * problematic (the preemption must not occur before the IPI 354 * has been acknowledged via an EOI). Instead, we 355 * intentionally ignore td_owepreempt when leaving the 356 * critical section. This should be harmless because we do 357 * not permit rendezvous action routines to schedule threads, 358 * and thus td_owepreempt should never transition from 0 to 1 359 * during this routine. 360 */ 361 td = curthread; 362 td->td_critnest++; 363 #ifdef INVARIANTS 364 owepreempt = td->td_owepreempt; 365 #endif 366 367 /* 368 * If requested, run a setup function before the main action 369 * function. Ensure all CPUs have completed the setup 370 * function before moving on to the action function. 371 */ 372 if (local_setup_func != smp_no_rendevous_barrier) { 373 if (smp_rv_setup_func != NULL) 374 smp_rv_setup_func(smp_rv_func_arg); 375 atomic_add_int(&smp_rv_waiters[1], 1); 376 while (smp_rv_waiters[1] < smp_rv_ncpus) 377 cpu_spinwait(); 378 } 379 380 if (local_action_func != NULL) 381 local_action_func(local_func_arg); 382 383 if (local_teardown_func != smp_no_rendevous_barrier) { 384 /* 385 * Signal that the main action has been completed. If a 386 * full exit rendezvous is requested, then all CPUs will 387 * wait here until all CPUs have finished the main action. 388 */ 389 atomic_add_int(&smp_rv_waiters[2], 1); 390 while (smp_rv_waiters[2] < smp_rv_ncpus) 391 cpu_spinwait(); 392 393 if (local_teardown_func != NULL) 394 local_teardown_func(local_func_arg); 395 } 396 397 /* 398 * Signal that the rendezvous is fully completed by this CPU. 399 * This means that no member of smp_rv_* pseudo-structure will be 400 * accessed by this target CPU after this point; in particular, 401 * memory pointed by smp_rv_func_arg. 402 */ 403 atomic_add_int(&smp_rv_waiters[3], 1); 404 405 td->td_critnest--; 406 KASSERT(owepreempt == td->td_owepreempt, 407 ("rendezvous action changed td_owepreempt")); 408 } 409 410 void 411 smp_rendezvous_cpus(cpuset_t map, 412 void (* setup_func)(void *), 413 void (* action_func)(void *), 414 void (* teardown_func)(void *), 415 void *arg) 416 { 417 int curcpumap, i, ncpus = 0; 418 419 /* Look comments in the !SMP case. */ 420 if (!smp_started) { 421 spinlock_enter(); 422 if (setup_func != NULL) 423 setup_func(arg); 424 if (action_func != NULL) 425 action_func(arg); 426 if (teardown_func != NULL) 427 teardown_func(arg); 428 spinlock_exit(); 429 return; 430 } 431 432 CPU_FOREACH(i) { 433 if (CPU_ISSET(i, &map)) 434 ncpus++; 435 } 436 if (ncpus == 0) 437 panic("ncpus is 0 with non-zero map"); 438 439 mtx_lock_spin(&smp_ipi_mtx); 440 441 /* Pass rendezvous parameters via global variables. */ 442 smp_rv_ncpus = ncpus; 443 smp_rv_setup_func = setup_func; 444 smp_rv_action_func = action_func; 445 smp_rv_teardown_func = teardown_func; 446 smp_rv_func_arg = arg; 447 smp_rv_waiters[1] = 0; 448 smp_rv_waiters[2] = 0; 449 smp_rv_waiters[3] = 0; 450 atomic_store_rel_int(&smp_rv_waiters[0], 0); 451 452 /* 453 * Signal other processors, which will enter the IPI with 454 * interrupts off. 455 */ 456 curcpumap = CPU_ISSET(curcpu, &map); 457 CPU_CLR(curcpu, &map); 458 ipi_selected(map, IPI_RENDEZVOUS); 459 460 /* Check if the current CPU is in the map */ 461 if (curcpumap != 0) 462 smp_rendezvous_action(); 463 464 /* 465 * Ensure that the master CPU waits for all the other 466 * CPUs to finish the rendezvous, so that smp_rv_* 467 * pseudo-structure and the arg are guaranteed to not 468 * be in use. 469 */ 470 while (atomic_load_acq_int(&smp_rv_waiters[3]) < ncpus) 471 cpu_spinwait(); 472 473 mtx_unlock_spin(&smp_ipi_mtx); 474 } 475 476 void 477 smp_rendezvous(void (* setup_func)(void *), 478 void (* action_func)(void *), 479 void (* teardown_func)(void *), 480 void *arg) 481 { 482 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); 483 } 484 485 static struct cpu_group group[MAXCPU]; 486 487 struct cpu_group * 488 smp_topo(void) 489 { 490 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 491 struct cpu_group *top; 492 493 /* 494 * Check for a fake topology request for debugging purposes. 495 */ 496 switch (smp_topology) { 497 case 1: 498 /* Dual core with no sharing. */ 499 top = smp_topo_1level(CG_SHARE_NONE, 2, 0); 500 break; 501 case 2: 502 /* No topology, all cpus are equal. */ 503 top = smp_topo_none(); 504 break; 505 case 3: 506 /* Dual core with shared L2. */ 507 top = smp_topo_1level(CG_SHARE_L2, 2, 0); 508 break; 509 case 4: 510 /* quad core, shared l3 among each package, private l2. */ 511 top = smp_topo_1level(CG_SHARE_L3, 4, 0); 512 break; 513 case 5: 514 /* quad core, 2 dualcore parts on each package share l2. */ 515 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); 516 break; 517 case 6: 518 /* Single-core 2xHTT */ 519 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); 520 break; 521 case 7: 522 /* quad core with a shared l3, 8 threads sharing L2. */ 523 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, 524 CG_FLAG_SMT); 525 break; 526 default: 527 /* Default, ask the system what it wants. */ 528 top = cpu_topo(); 529 break; 530 } 531 /* 532 * Verify the returned topology. 533 */ 534 if (top->cg_count != mp_ncpus) 535 panic("Built bad topology at %p. CPU count %d != %d", 536 top, top->cg_count, mp_ncpus); 537 if (CPU_CMP(&top->cg_mask, &all_cpus)) 538 panic("Built bad topology at %p. CPU mask (%s) != (%s)", 539 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), 540 cpusetobj_strprint(cpusetbuf2, &all_cpus)); 541 return (top); 542 } 543 544 struct cpu_group * 545 smp_topo_none(void) 546 { 547 struct cpu_group *top; 548 549 top = &group[0]; 550 top->cg_parent = NULL; 551 top->cg_child = NULL; 552 top->cg_mask = all_cpus; 553 top->cg_count = mp_ncpus; 554 top->cg_children = 0; 555 top->cg_level = CG_SHARE_NONE; 556 top->cg_flags = 0; 557 558 return (top); 559 } 560 561 static int 562 smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, 563 int count, int flags, int start) 564 { 565 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 566 cpuset_t mask; 567 int i; 568 569 CPU_ZERO(&mask); 570 for (i = 0; i < count; i++, start++) 571 CPU_SET(start, &mask); 572 child->cg_parent = parent; 573 child->cg_child = NULL; 574 child->cg_children = 0; 575 child->cg_level = share; 576 child->cg_count = count; 577 child->cg_flags = flags; 578 child->cg_mask = mask; 579 parent->cg_children++; 580 for (; parent != NULL; parent = parent->cg_parent) { 581 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) 582 panic("Duplicate children in %p. mask (%s) child (%s)", 583 parent, 584 cpusetobj_strprint(cpusetbuf, &parent->cg_mask), 585 cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); 586 CPU_OR(&parent->cg_mask, &child->cg_mask); 587 parent->cg_count += child->cg_count; 588 } 589 590 return (start); 591 } 592 593 struct cpu_group * 594 smp_topo_1level(int share, int count, int flags) 595 { 596 struct cpu_group *child; 597 struct cpu_group *top; 598 int packages; 599 int cpu; 600 int i; 601 602 cpu = 0; 603 top = &group[0]; 604 packages = mp_ncpus / count; 605 top->cg_child = child = &group[1]; 606 top->cg_level = CG_SHARE_NONE; 607 for (i = 0; i < packages; i++, child++) 608 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); 609 return (top); 610 } 611 612 struct cpu_group * 613 smp_topo_2level(int l2share, int l2count, int l1share, int l1count, 614 int l1flags) 615 { 616 struct cpu_group *top; 617 struct cpu_group *l1g; 618 struct cpu_group *l2g; 619 int cpu; 620 int i; 621 int j; 622 623 cpu = 0; 624 top = &group[0]; 625 l2g = &group[1]; 626 top->cg_child = l2g; 627 top->cg_level = CG_SHARE_NONE; 628 top->cg_children = mp_ncpus / (l2count * l1count); 629 l1g = l2g + top->cg_children; 630 for (i = 0; i < top->cg_children; i++, l2g++) { 631 l2g->cg_parent = top; 632 l2g->cg_child = l1g; 633 l2g->cg_level = l2share; 634 for (j = 0; j < l2count; j++, l1g++) 635 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, 636 l1flags, cpu); 637 } 638 return (top); 639 } 640 641 642 struct cpu_group * 643 smp_topo_find(struct cpu_group *top, int cpu) 644 { 645 struct cpu_group *cg; 646 cpuset_t mask; 647 int children; 648 int i; 649 650 CPU_SETOF(cpu, &mask); 651 cg = top; 652 for (;;) { 653 if (!CPU_OVERLAP(&cg->cg_mask, &mask)) 654 return (NULL); 655 if (cg->cg_children == 0) 656 return (cg); 657 children = cg->cg_children; 658 for (i = 0, cg = cg->cg_child; i < children; cg++, i++) 659 if (CPU_OVERLAP(&cg->cg_mask, &mask)) 660 break; 661 } 662 return (NULL); 663 } 664 #else /* !SMP */ 665 666 void 667 smp_rendezvous_cpus(cpuset_t map, 668 void (*setup_func)(void *), 669 void (*action_func)(void *), 670 void (*teardown_func)(void *), 671 void *arg) 672 { 673 /* 674 * In the !SMP case we just need to ensure the same initial conditions 675 * as the SMP case. 676 */ 677 spinlock_enter(); 678 if (setup_func != NULL) 679 setup_func(arg); 680 if (action_func != NULL) 681 action_func(arg); 682 if (teardown_func != NULL) 683 teardown_func(arg); 684 spinlock_exit(); 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 /* Look comments in the smp_rendezvous_cpus() case. */ 695 spinlock_enter(); 696 if (setup_func != NULL) 697 setup_func(arg); 698 if (action_func != NULL) 699 action_func(arg); 700 if (teardown_func != NULL) 701 teardown_func(arg); 702 spinlock_exit(); 703 } 704 705 /* 706 * Provide dummy SMP support for UP kernels. Modules that need to use SMP 707 * APIs will still work using this dummy support. 708 */ 709 static void 710 mp_setvariables_for_up(void *dummy) 711 { 712 mp_ncpus = 1; 713 mp_maxid = PCPU_GET(cpuid); 714 CPU_SETOF(mp_maxid, &all_cpus); 715 KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero")); 716 } 717 SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST, 718 mp_setvariables_for_up, NULL); 719 #endif /* SMP */ 720 721 void 722 smp_no_rendevous_barrier(void *dummy) 723 { 724 #ifdef SMP 725 KASSERT((!smp_started),("smp_no_rendevous called and smp is started")); 726 #endif 727 } 728