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/sched.h> 48 #include <sys/smp.h> 49 #include <sys/sysctl.h> 50 51 #include <machine/cpu.h> 52 #include <machine/smp.h> 53 54 #include "opt_sched.h" 55 56 #ifdef SMP 57 volatile cpuset_t stopped_cpus; 58 volatile cpuset_t started_cpus; 59 volatile cpuset_t suspended_cpus; 60 cpuset_t hlt_cpus_mask; 61 cpuset_t logical_cpus_mask; 62 63 void (*cpustop_restartfunc)(void); 64 #endif 65 /* This is used in modules that need to work in both SMP and UP. */ 66 cpuset_t all_cpus; 67 68 int mp_ncpus; 69 /* export this for libkvm consumers. */ 70 int mp_maxcpus = MAXCPU; 71 72 volatile int smp_started; 73 u_int mp_maxid; 74 75 static SYSCTL_NODE(_kern, OID_AUTO, smp, CTLFLAG_RD|CTLFLAG_CAPRD, NULL, 76 "Kernel SMP"); 77 78 SYSCTL_INT(_kern_smp, OID_AUTO, maxid, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxid, 0, 79 "Max CPU ID."); 80 81 SYSCTL_INT(_kern_smp, OID_AUTO, maxcpus, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxcpus, 82 0, "Max number of CPUs that the system was compiled for."); 83 84 int smp_active = 0; /* are the APs allowed to run? */ 85 SYSCTL_INT(_kern_smp, OID_AUTO, active, CTLFLAG_RW, &smp_active, 0, 86 "Number of Auxillary Processors (APs) that were successfully started"); 87 88 int smp_disabled = 0; /* has smp been disabled? */ 89 SYSCTL_INT(_kern_smp, OID_AUTO, disabled, CTLFLAG_RDTUN|CTLFLAG_CAPRD, 90 &smp_disabled, 0, "SMP has been disabled from the loader"); 91 TUNABLE_INT("kern.smp.disabled", &smp_disabled); 92 93 int smp_cpus = 1; /* how many cpu's running */ 94 SYSCTL_INT(_kern_smp, OID_AUTO, cpus, CTLFLAG_RD|CTLFLAG_CAPRD, &smp_cpus, 0, 95 "Number of CPUs online"); 96 97 int smp_topology = 0; /* Which topology we're using. */ 98 SYSCTL_INT(_kern_smp, OID_AUTO, topology, CTLFLAG_RD, &smp_topology, 0, 99 "Topology override setting; 0 is default provided by hardware."); 100 TUNABLE_INT("kern.smp.topology", &smp_topology); 101 102 #ifdef SMP 103 /* Enable forwarding of a signal to a process running on a different CPU */ 104 static int forward_signal_enabled = 1; 105 SYSCTL_INT(_kern_smp, OID_AUTO, forward_signal_enabled, CTLFLAG_RW, 106 &forward_signal_enabled, 0, 107 "Forwarding of a signal to a process on a different CPU"); 108 109 /* Variables needed for SMP rendezvous. */ 110 static volatile int smp_rv_ncpus; 111 static void (*volatile smp_rv_setup_func)(void *arg); 112 static void (*volatile smp_rv_action_func)(void *arg); 113 static void (*volatile smp_rv_teardown_func)(void *arg); 114 static void *volatile smp_rv_func_arg; 115 static volatile int smp_rv_waiters[4]; 116 117 /* 118 * Shared mutex to restrict busywaits between smp_rendezvous() and 119 * smp(_targeted)_tlb_shootdown(). A deadlock occurs if both of these 120 * functions trigger at once and cause multiple CPUs to busywait with 121 * interrupts disabled. 122 */ 123 struct mtx smp_ipi_mtx; 124 125 /* 126 * Let the MD SMP code initialize mp_maxid very early if it can. 127 */ 128 static void 129 mp_setmaxid(void *dummy) 130 { 131 cpu_mp_setmaxid(); 132 } 133 SYSINIT(cpu_mp_setmaxid, SI_SUB_TUNABLES, SI_ORDER_FIRST, mp_setmaxid, NULL); 134 135 /* 136 * Call the MD SMP initialization code. 137 */ 138 static void 139 mp_start(void *dummy) 140 { 141 142 mtx_init(&smp_ipi_mtx, "smp rendezvous", NULL, MTX_SPIN); 143 144 /* Probe for MP hardware. */ 145 if (smp_disabled != 0 || cpu_mp_probe() == 0) { 146 mp_ncpus = 1; 147 CPU_SETOF(PCPU_GET(cpuid), &all_cpus); 148 return; 149 } 150 151 cpu_mp_start(); 152 printf("FreeBSD/SMP: Multiprocessor System Detected: %d CPUs\n", 153 mp_ncpus); 154 cpu_mp_announce(); 155 } 156 SYSINIT(cpu_mp, SI_SUB_CPU, SI_ORDER_THIRD, mp_start, NULL); 157 158 void 159 forward_signal(struct thread *td) 160 { 161 int id; 162 163 /* 164 * signotify() has already set TDF_ASTPENDING and TDF_NEEDSIGCHECK on 165 * this thread, so all we need to do is poke it if it is currently 166 * executing so that it executes ast(). 167 */ 168 THREAD_LOCK_ASSERT(td, MA_OWNED); 169 KASSERT(TD_IS_RUNNING(td), 170 ("forward_signal: thread is not TDS_RUNNING")); 171 172 CTR1(KTR_SMP, "forward_signal(%p)", td->td_proc); 173 174 if (!smp_started || cold || panicstr) 175 return; 176 if (!forward_signal_enabled) 177 return; 178 179 /* No need to IPI ourself. */ 180 if (td == curthread) 181 return; 182 183 id = td->td_oncpu; 184 if (id == NOCPU) 185 return; 186 ipi_cpu(id, IPI_AST); 187 } 188 189 /* 190 * When called the executing CPU will send an IPI to all other CPUs 191 * requesting that they halt execution. 192 * 193 * Usually (but not necessarily) called with 'other_cpus' as its arg. 194 * 195 * - Signals all CPUs in map to stop. 196 * - Waits for each to stop. 197 * 198 * Returns: 199 * -1: error 200 * 0: NA 201 * 1: ok 202 * 203 */ 204 static int 205 generic_stop_cpus(cpuset_t map, u_int type) 206 { 207 #ifdef KTR 208 char cpusetbuf[CPUSETBUFSIZ]; 209 #endif 210 static volatile u_int stopping_cpu = NOCPU; 211 int i; 212 volatile cpuset_t *cpus; 213 214 KASSERT( 215 #if defined(__amd64__) || defined(__i386__) 216 type == IPI_STOP || type == IPI_STOP_HARD || type == IPI_SUSPEND, 217 #else 218 type == IPI_STOP || type == IPI_STOP_HARD, 219 #endif 220 ("%s: invalid stop type", __func__)); 221 222 if (!smp_started) 223 return (0); 224 225 CTR2(KTR_SMP, "stop_cpus(%s) with %u type", 226 cpusetobj_strprint(cpusetbuf, &map), type); 227 228 #if defined(__amd64__) || defined(__i386__) 229 /* 230 * When suspending, ensure there are are no IPIs in progress. 231 * IPIs that have been issued, but not yet delivered (e.g. 232 * not pending on a vCPU when running under virtualization) 233 * will be lost, violating FreeBSD's assumption of reliable 234 * IPI delivery. 235 */ 236 if (type == IPI_SUSPEND) 237 mtx_lock_spin(&smp_ipi_mtx); 238 #endif 239 240 if (stopping_cpu != PCPU_GET(cpuid)) 241 while (atomic_cmpset_int(&stopping_cpu, NOCPU, 242 PCPU_GET(cpuid)) == 0) 243 while (stopping_cpu != NOCPU) 244 cpu_spinwait(); /* spin */ 245 246 /* send the stop IPI to all CPUs in map */ 247 ipi_selected(map, type); 248 249 #if defined(__amd64__) || defined(__i386__) 250 if (type == IPI_SUSPEND) 251 cpus = &suspended_cpus; 252 else 253 #endif 254 cpus = &stopped_cpus; 255 256 i = 0; 257 while (!CPU_SUBSET(cpus, &map)) { 258 /* spin */ 259 cpu_spinwait(); 260 i++; 261 if (i == 100000000) { 262 printf("timeout stopping cpus\n"); 263 break; 264 } 265 } 266 267 #if defined(__amd64__) || defined(__i386__) 268 if (type == IPI_SUSPEND) 269 mtx_unlock_spin(&smp_ipi_mtx); 270 #endif 271 272 stopping_cpu = NOCPU; 273 return (1); 274 } 275 276 int 277 stop_cpus(cpuset_t map) 278 { 279 280 return (generic_stop_cpus(map, IPI_STOP)); 281 } 282 283 int 284 stop_cpus_hard(cpuset_t map) 285 { 286 287 return (generic_stop_cpus(map, IPI_STOP_HARD)); 288 } 289 290 #if defined(__amd64__) || defined(__i386__) 291 int 292 suspend_cpus(cpuset_t map) 293 { 294 295 return (generic_stop_cpus(map, IPI_SUSPEND)); 296 } 297 #endif 298 299 /* 300 * Called by a CPU to restart stopped CPUs. 301 * 302 * Usually (but not necessarily) called with 'stopped_cpus' as its arg. 303 * 304 * - Signals all CPUs in map to restart. 305 * - Waits for each to restart. 306 * 307 * Returns: 308 * -1: error 309 * 0: NA 310 * 1: ok 311 */ 312 static int 313 generic_restart_cpus(cpuset_t map, u_int type) 314 { 315 #ifdef KTR 316 char cpusetbuf[CPUSETBUFSIZ]; 317 #endif 318 volatile cpuset_t *cpus; 319 320 KASSERT( 321 #if defined(__amd64__) || defined(__i386__) 322 type == IPI_STOP || type == IPI_STOP_HARD || type == IPI_SUSPEND, 323 #else 324 type == IPI_STOP || type == IPI_STOP_HARD, 325 #endif 326 ("%s: invalid stop type", __func__)); 327 328 if (!smp_started) 329 return 0; 330 331 CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); 332 333 #if defined(__amd64__) || defined(__i386__) 334 if (type == IPI_SUSPEND) 335 cpus = &suspended_cpus; 336 else 337 #endif 338 cpus = &stopped_cpus; 339 340 /* signal other cpus to restart */ 341 CPU_COPY_STORE_REL(&map, &started_cpus); 342 343 /* wait for each to clear its bit */ 344 while (CPU_OVERLAP(cpus, &map)) 345 cpu_spinwait(); 346 347 return 1; 348 } 349 350 int 351 restart_cpus(cpuset_t map) 352 { 353 354 return (generic_restart_cpus(map, IPI_STOP)); 355 } 356 357 #if defined(__amd64__) || defined(__i386__) 358 int 359 resume_cpus(cpuset_t map) 360 { 361 362 return (generic_restart_cpus(map, IPI_SUSPEND)); 363 } 364 #endif 365 366 /* 367 * All-CPU rendezvous. CPUs are signalled, all execute the setup function 368 * (if specified), rendezvous, execute the action function (if specified), 369 * rendezvous again, execute the teardown function (if specified), and then 370 * resume. 371 * 372 * Note that the supplied external functions _must_ be reentrant and aware 373 * that they are running in parallel and in an unknown lock context. 374 */ 375 void 376 smp_rendezvous_action(void) 377 { 378 struct thread *td; 379 void *local_func_arg; 380 void (*local_setup_func)(void*); 381 void (*local_action_func)(void*); 382 void (*local_teardown_func)(void*); 383 #ifdef INVARIANTS 384 int owepreempt; 385 #endif 386 387 /* Ensure we have up-to-date values. */ 388 atomic_add_acq_int(&smp_rv_waiters[0], 1); 389 while (smp_rv_waiters[0] < smp_rv_ncpus) 390 cpu_spinwait(); 391 392 /* Fetch rendezvous parameters after acquire barrier. */ 393 local_func_arg = smp_rv_func_arg; 394 local_setup_func = smp_rv_setup_func; 395 local_action_func = smp_rv_action_func; 396 local_teardown_func = smp_rv_teardown_func; 397 398 /* 399 * Use a nested critical section to prevent any preemptions 400 * from occurring during a rendezvous action routine. 401 * Specifically, if a rendezvous handler is invoked via an IPI 402 * and the interrupted thread was in the critical_exit() 403 * function after setting td_critnest to 0 but before 404 * performing a deferred preemption, this routine can be 405 * invoked with td_critnest set to 0 and td_owepreempt true. 406 * In that case, a critical_exit() during the rendezvous 407 * action would trigger a preemption which is not permitted in 408 * a rendezvous action. To fix this, wrap all of the 409 * rendezvous action handlers in a critical section. We 410 * cannot use a regular critical section however as having 411 * critical_exit() preempt from this routine would also be 412 * problematic (the preemption must not occur before the IPI 413 * has been acknowledged via an EOI). Instead, we 414 * intentionally ignore td_owepreempt when leaving the 415 * critical section. This should be harmless because we do 416 * not permit rendezvous action routines to schedule threads, 417 * and thus td_owepreempt should never transition from 0 to 1 418 * during this routine. 419 */ 420 td = curthread; 421 td->td_critnest++; 422 #ifdef INVARIANTS 423 owepreempt = td->td_owepreempt; 424 #endif 425 426 /* 427 * If requested, run a setup function before the main action 428 * function. Ensure all CPUs have completed the setup 429 * function before moving on to the action function. 430 */ 431 if (local_setup_func != smp_no_rendevous_barrier) { 432 if (smp_rv_setup_func != NULL) 433 smp_rv_setup_func(smp_rv_func_arg); 434 atomic_add_int(&smp_rv_waiters[1], 1); 435 while (smp_rv_waiters[1] < smp_rv_ncpus) 436 cpu_spinwait(); 437 } 438 439 if (local_action_func != NULL) 440 local_action_func(local_func_arg); 441 442 if (local_teardown_func != smp_no_rendevous_barrier) { 443 /* 444 * Signal that the main action has been completed. If a 445 * full exit rendezvous is requested, then all CPUs will 446 * wait here until all CPUs have finished the main action. 447 */ 448 atomic_add_int(&smp_rv_waiters[2], 1); 449 while (smp_rv_waiters[2] < smp_rv_ncpus) 450 cpu_spinwait(); 451 452 if (local_teardown_func != NULL) 453 local_teardown_func(local_func_arg); 454 } 455 456 /* 457 * Signal that the rendezvous is fully completed by this CPU. 458 * This means that no member of smp_rv_* pseudo-structure will be 459 * accessed by this target CPU after this point; in particular, 460 * memory pointed by smp_rv_func_arg. 461 */ 462 atomic_add_int(&smp_rv_waiters[3], 1); 463 464 td->td_critnest--; 465 KASSERT(owepreempt == td->td_owepreempt, 466 ("rendezvous action changed td_owepreempt")); 467 } 468 469 void 470 smp_rendezvous_cpus(cpuset_t map, 471 void (* setup_func)(void *), 472 void (* action_func)(void *), 473 void (* teardown_func)(void *), 474 void *arg) 475 { 476 int curcpumap, i, ncpus = 0; 477 478 /* Look comments in the !SMP case. */ 479 if (!smp_started) { 480 spinlock_enter(); 481 if (setup_func != NULL) 482 setup_func(arg); 483 if (action_func != NULL) 484 action_func(arg); 485 if (teardown_func != NULL) 486 teardown_func(arg); 487 spinlock_exit(); 488 return; 489 } 490 491 CPU_FOREACH(i) { 492 if (CPU_ISSET(i, &map)) 493 ncpus++; 494 } 495 if (ncpus == 0) 496 panic("ncpus is 0 with non-zero map"); 497 498 mtx_lock_spin(&smp_ipi_mtx); 499 500 /* Pass rendezvous parameters via global variables. */ 501 smp_rv_ncpus = ncpus; 502 smp_rv_setup_func = setup_func; 503 smp_rv_action_func = action_func; 504 smp_rv_teardown_func = teardown_func; 505 smp_rv_func_arg = arg; 506 smp_rv_waiters[1] = 0; 507 smp_rv_waiters[2] = 0; 508 smp_rv_waiters[3] = 0; 509 atomic_store_rel_int(&smp_rv_waiters[0], 0); 510 511 /* 512 * Signal other processors, which will enter the IPI with 513 * interrupts off. 514 */ 515 curcpumap = CPU_ISSET(curcpu, &map); 516 CPU_CLR(curcpu, &map); 517 ipi_selected(map, IPI_RENDEZVOUS); 518 519 /* Check if the current CPU is in the map */ 520 if (curcpumap != 0) 521 smp_rendezvous_action(); 522 523 /* 524 * Ensure that the master CPU waits for all the other 525 * CPUs to finish the rendezvous, so that smp_rv_* 526 * pseudo-structure and the arg are guaranteed to not 527 * be in use. 528 */ 529 while (atomic_load_acq_int(&smp_rv_waiters[3]) < ncpus) 530 cpu_spinwait(); 531 532 mtx_unlock_spin(&smp_ipi_mtx); 533 } 534 535 void 536 smp_rendezvous(void (* setup_func)(void *), 537 void (* action_func)(void *), 538 void (* teardown_func)(void *), 539 void *arg) 540 { 541 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); 542 } 543 544 static struct cpu_group group[MAXCPU]; 545 546 struct cpu_group * 547 smp_topo(void) 548 { 549 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 550 struct cpu_group *top; 551 552 /* 553 * Check for a fake topology request for debugging purposes. 554 */ 555 switch (smp_topology) { 556 case 1: 557 /* Dual core with no sharing. */ 558 top = smp_topo_1level(CG_SHARE_NONE, 2, 0); 559 break; 560 case 2: 561 /* No topology, all cpus are equal. */ 562 top = smp_topo_none(); 563 break; 564 case 3: 565 /* Dual core with shared L2. */ 566 top = smp_topo_1level(CG_SHARE_L2, 2, 0); 567 break; 568 case 4: 569 /* quad core, shared l3 among each package, private l2. */ 570 top = smp_topo_1level(CG_SHARE_L3, 4, 0); 571 break; 572 case 5: 573 /* quad core, 2 dualcore parts on each package share l2. */ 574 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); 575 break; 576 case 6: 577 /* Single-core 2xHTT */ 578 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); 579 break; 580 case 7: 581 /* quad core with a shared l3, 8 threads sharing L2. */ 582 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, 583 CG_FLAG_SMT); 584 break; 585 default: 586 /* Default, ask the system what it wants. */ 587 top = cpu_topo(); 588 break; 589 } 590 /* 591 * Verify the returned topology. 592 */ 593 if (top->cg_count != mp_ncpus) 594 panic("Built bad topology at %p. CPU count %d != %d", 595 top, top->cg_count, mp_ncpus); 596 if (CPU_CMP(&top->cg_mask, &all_cpus)) 597 panic("Built bad topology at %p. CPU mask (%s) != (%s)", 598 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), 599 cpusetobj_strprint(cpusetbuf2, &all_cpus)); 600 return (top); 601 } 602 603 struct cpu_group * 604 smp_topo_none(void) 605 { 606 struct cpu_group *top; 607 608 top = &group[0]; 609 top->cg_parent = NULL; 610 top->cg_child = NULL; 611 top->cg_mask = all_cpus; 612 top->cg_count = mp_ncpus; 613 top->cg_children = 0; 614 top->cg_level = CG_SHARE_NONE; 615 top->cg_flags = 0; 616 617 return (top); 618 } 619 620 static int 621 smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, 622 int count, int flags, int start) 623 { 624 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 625 cpuset_t mask; 626 int i; 627 628 CPU_ZERO(&mask); 629 for (i = 0; i < count; i++, start++) 630 CPU_SET(start, &mask); 631 child->cg_parent = parent; 632 child->cg_child = NULL; 633 child->cg_children = 0; 634 child->cg_level = share; 635 child->cg_count = count; 636 child->cg_flags = flags; 637 child->cg_mask = mask; 638 parent->cg_children++; 639 for (; parent != NULL; parent = parent->cg_parent) { 640 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) 641 panic("Duplicate children in %p. mask (%s) child (%s)", 642 parent, 643 cpusetobj_strprint(cpusetbuf, &parent->cg_mask), 644 cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); 645 CPU_OR(&parent->cg_mask, &child->cg_mask); 646 parent->cg_count += child->cg_count; 647 } 648 649 return (start); 650 } 651 652 struct cpu_group * 653 smp_topo_1level(int share, int count, int flags) 654 { 655 struct cpu_group *child; 656 struct cpu_group *top; 657 int packages; 658 int cpu; 659 int i; 660 661 cpu = 0; 662 top = &group[0]; 663 packages = mp_ncpus / count; 664 top->cg_child = child = &group[1]; 665 top->cg_level = CG_SHARE_NONE; 666 for (i = 0; i < packages; i++, child++) 667 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); 668 return (top); 669 } 670 671 struct cpu_group * 672 smp_topo_2level(int l2share, int l2count, int l1share, int l1count, 673 int l1flags) 674 { 675 struct cpu_group *top; 676 struct cpu_group *l1g; 677 struct cpu_group *l2g; 678 int cpu; 679 int i; 680 int j; 681 682 cpu = 0; 683 top = &group[0]; 684 l2g = &group[1]; 685 top->cg_child = l2g; 686 top->cg_level = CG_SHARE_NONE; 687 top->cg_children = mp_ncpus / (l2count * l1count); 688 l1g = l2g + top->cg_children; 689 for (i = 0; i < top->cg_children; i++, l2g++) { 690 l2g->cg_parent = top; 691 l2g->cg_child = l1g; 692 l2g->cg_level = l2share; 693 for (j = 0; j < l2count; j++, l1g++) 694 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, 695 l1flags, cpu); 696 } 697 return (top); 698 } 699 700 701 struct cpu_group * 702 smp_topo_find(struct cpu_group *top, int cpu) 703 { 704 struct cpu_group *cg; 705 cpuset_t mask; 706 int children; 707 int i; 708 709 CPU_SETOF(cpu, &mask); 710 cg = top; 711 for (;;) { 712 if (!CPU_OVERLAP(&cg->cg_mask, &mask)) 713 return (NULL); 714 if (cg->cg_children == 0) 715 return (cg); 716 children = cg->cg_children; 717 for (i = 0, cg = cg->cg_child; i < children; cg++, i++) 718 if (CPU_OVERLAP(&cg->cg_mask, &mask)) 719 break; 720 } 721 return (NULL); 722 } 723 #else /* !SMP */ 724 725 void 726 smp_rendezvous_cpus(cpuset_t map, 727 void (*setup_func)(void *), 728 void (*action_func)(void *), 729 void (*teardown_func)(void *), 730 void *arg) 731 { 732 /* 733 * In the !SMP case we just need to ensure the same initial conditions 734 * as the SMP case. 735 */ 736 spinlock_enter(); 737 if (setup_func != NULL) 738 setup_func(arg); 739 if (action_func != NULL) 740 action_func(arg); 741 if (teardown_func != NULL) 742 teardown_func(arg); 743 spinlock_exit(); 744 } 745 746 void 747 smp_rendezvous(void (*setup_func)(void *), 748 void (*action_func)(void *), 749 void (*teardown_func)(void *), 750 void *arg) 751 { 752 753 /* Look comments in the smp_rendezvous_cpus() case. */ 754 spinlock_enter(); 755 if (setup_func != NULL) 756 setup_func(arg); 757 if (action_func != NULL) 758 action_func(arg); 759 if (teardown_func != NULL) 760 teardown_func(arg); 761 spinlock_exit(); 762 } 763 764 /* 765 * Provide dummy SMP support for UP kernels. Modules that need to use SMP 766 * APIs will still work using this dummy support. 767 */ 768 static void 769 mp_setvariables_for_up(void *dummy) 770 { 771 mp_ncpus = 1; 772 mp_maxid = PCPU_GET(cpuid); 773 CPU_SETOF(mp_maxid, &all_cpus); 774 KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero")); 775 } 776 SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST, 777 mp_setvariables_for_up, NULL); 778 #endif /* SMP */ 779 780 void 781 smp_no_rendevous_barrier(void *dummy) 782 { 783 #ifdef SMP 784 KASSERT((!smp_started),("smp_no_rendevous called and smp is started")); 785 #endif 786 } 787 788 /* 789 * Wait specified idle threads to switch once. This ensures that even 790 * preempted threads have cycled through the switch function once, 791 * exiting their codepaths. This allows us to change global pointers 792 * with no other synchronization. 793 */ 794 int 795 quiesce_cpus(cpuset_t map, const char *wmesg, int prio) 796 { 797 struct pcpu *pcpu; 798 u_int gen[MAXCPU]; 799 int error; 800 int cpu; 801 802 error = 0; 803 for (cpu = 0; cpu <= mp_maxid; cpu++) { 804 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 805 continue; 806 pcpu = pcpu_find(cpu); 807 gen[cpu] = pcpu->pc_idlethread->td_generation; 808 } 809 for (cpu = 0; cpu <= mp_maxid; cpu++) { 810 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 811 continue; 812 pcpu = pcpu_find(cpu); 813 thread_lock(curthread); 814 sched_bind(curthread, cpu); 815 thread_unlock(curthread); 816 while (gen[cpu] == pcpu->pc_idlethread->td_generation) { 817 error = tsleep(quiesce_cpus, prio, wmesg, 1); 818 if (error != EWOULDBLOCK) 819 goto out; 820 error = 0; 821 } 822 } 823 out: 824 thread_lock(curthread); 825 sched_unbind(curthread); 826 thread_unlock(curthread); 827 828 return (error); 829 } 830 831 int 832 quiesce_all_cpus(const char *wmesg, int prio) 833 { 834 835 return quiesce_cpus(all_cpus, wmesg, prio); 836 } 837