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 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 /* 28 * This module holds the global variables and machine independent functions 29 * used for the kernel SMP support. 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/kernel.h> 38 #include <sys/ktr.h> 39 #include <sys/proc.h> 40 #include <sys/bus.h> 41 #include <sys/lock.h> 42 #include <sys/mutex.h> 43 #include <sys/pcpu.h> 44 #include <sys/sched.h> 45 #include <sys/smp.h> 46 #include <sys/sysctl.h> 47 48 #include <machine/cpu.h> 49 #include <machine/smp.h> 50 51 #include "opt_sched.h" 52 53 #ifdef SMP 54 volatile cpuset_t stopped_cpus; 55 volatile cpuset_t started_cpus; 56 volatile cpuset_t suspended_cpus; 57 cpuset_t hlt_cpus_mask; 58 cpuset_t logical_cpus_mask; 59 60 void (*cpustop_restartfunc)(void); 61 #endif 62 63 static int sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS); 64 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 SYSCTL_PROC(_kern_smp, OID_AUTO, active, CTLFLAG_RD | CTLTYPE_INT, NULL, 0, 85 sysctl_kern_smp_active, "I", "Indicates system is running in SMP mode"); 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 defined(__amd64__) || defined(__i386__) 228 /* 229 * When suspending, ensure there are are no IPIs in progress. 230 * IPIs that have been issued, but not yet delivered (e.g. 231 * not pending on a vCPU when running under virtualization) 232 * will be lost, violating FreeBSD's assumption of reliable 233 * IPI delivery. 234 */ 235 if (type == IPI_SUSPEND) 236 mtx_lock_spin(&smp_ipi_mtx); 237 #endif 238 239 if (stopping_cpu != PCPU_GET(cpuid)) 240 while (atomic_cmpset_int(&stopping_cpu, NOCPU, 241 PCPU_GET(cpuid)) == 0) 242 while (stopping_cpu != NOCPU) 243 cpu_spinwait(); /* spin */ 244 245 /* send the stop IPI to all CPUs in map */ 246 ipi_selected(map, type); 247 248 #if defined(__amd64__) || defined(__i386__) 249 if (type == IPI_SUSPEND) 250 cpus = &suspended_cpus; 251 else 252 #endif 253 cpus = &stopped_cpus; 254 255 i = 0; 256 while (!CPU_SUBSET(cpus, &map)) { 257 /* spin */ 258 cpu_spinwait(); 259 i++; 260 if (i == 100000000) { 261 printf("timeout stopping cpus\n"); 262 break; 263 } 264 } 265 266 #if defined(__amd64__) || defined(__i386__) 267 if (type == IPI_SUSPEND) 268 mtx_unlock_spin(&smp_ipi_mtx); 269 #endif 270 271 stopping_cpu = NOCPU; 272 return (1); 273 } 274 275 int 276 stop_cpus(cpuset_t map) 277 { 278 279 return (generic_stop_cpus(map, IPI_STOP)); 280 } 281 282 int 283 stop_cpus_hard(cpuset_t map) 284 { 285 286 return (generic_stop_cpus(map, IPI_STOP_HARD)); 287 } 288 289 #if defined(__amd64__) || defined(__i386__) 290 int 291 suspend_cpus(cpuset_t map) 292 { 293 294 return (generic_stop_cpus(map, IPI_SUSPEND)); 295 } 296 #endif 297 298 /* 299 * Called by a CPU to restart stopped CPUs. 300 * 301 * Usually (but not necessarily) called with 'stopped_cpus' as its arg. 302 * 303 * - Signals all CPUs in map to restart. 304 * - Waits for each to restart. 305 * 306 * Returns: 307 * -1: error 308 * 0: NA 309 * 1: ok 310 */ 311 static int 312 generic_restart_cpus(cpuset_t map, u_int type) 313 { 314 #ifdef KTR 315 char cpusetbuf[CPUSETBUFSIZ]; 316 #endif 317 volatile cpuset_t *cpus; 318 319 KASSERT( 320 #if defined(__amd64__) || defined(__i386__) 321 type == IPI_STOP || type == IPI_STOP_HARD || type == IPI_SUSPEND, 322 #else 323 type == IPI_STOP || type == IPI_STOP_HARD, 324 #endif 325 ("%s: invalid stop type", __func__)); 326 327 if (!smp_started) 328 return 0; 329 330 CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); 331 332 #if defined(__amd64__) || defined(__i386__) 333 if (type == IPI_SUSPEND) 334 cpus = &suspended_cpus; 335 else 336 #endif 337 cpus = &stopped_cpus; 338 339 /* signal other cpus to restart */ 340 CPU_COPY_STORE_REL(&map, &started_cpus); 341 342 /* wait for each to clear its bit */ 343 while (CPU_OVERLAP(cpus, &map)) 344 cpu_spinwait(); 345 346 return 1; 347 } 348 349 int 350 restart_cpus(cpuset_t map) 351 { 352 353 return (generic_restart_cpus(map, IPI_STOP)); 354 } 355 356 #if defined(__amd64__) || defined(__i386__) 357 int 358 resume_cpus(cpuset_t map) 359 { 360 361 return (generic_restart_cpus(map, IPI_SUSPEND)); 362 } 363 #endif 364 365 /* 366 * All-CPU rendezvous. CPUs are signalled, all execute the setup function 367 * (if specified), rendezvous, execute the action function (if specified), 368 * rendezvous again, execute the teardown function (if specified), and then 369 * resume. 370 * 371 * Note that the supplied external functions _must_ be reentrant and aware 372 * that they are running in parallel and in an unknown lock context. 373 */ 374 void 375 smp_rendezvous_action(void) 376 { 377 struct thread *td; 378 void *local_func_arg; 379 void (*local_setup_func)(void*); 380 void (*local_action_func)(void*); 381 void (*local_teardown_func)(void*); 382 #ifdef INVARIANTS 383 int owepreempt; 384 #endif 385 386 /* Ensure we have up-to-date values. */ 387 atomic_add_acq_int(&smp_rv_waiters[0], 1); 388 while (smp_rv_waiters[0] < smp_rv_ncpus) 389 cpu_spinwait(); 390 391 /* Fetch rendezvous parameters after acquire barrier. */ 392 local_func_arg = smp_rv_func_arg; 393 local_setup_func = smp_rv_setup_func; 394 local_action_func = smp_rv_action_func; 395 local_teardown_func = smp_rv_teardown_func; 396 397 /* 398 * Use a nested critical section to prevent any preemptions 399 * from occurring during a rendezvous action routine. 400 * Specifically, if a rendezvous handler is invoked via an IPI 401 * and the interrupted thread was in the critical_exit() 402 * function after setting td_critnest to 0 but before 403 * performing a deferred preemption, this routine can be 404 * invoked with td_critnest set to 0 and td_owepreempt true. 405 * In that case, a critical_exit() during the rendezvous 406 * action would trigger a preemption which is not permitted in 407 * a rendezvous action. To fix this, wrap all of the 408 * rendezvous action handlers in a critical section. We 409 * cannot use a regular critical section however as having 410 * critical_exit() preempt from this routine would also be 411 * problematic (the preemption must not occur before the IPI 412 * has been acknowledged via an EOI). Instead, we 413 * intentionally ignore td_owepreempt when leaving the 414 * critical section. This should be harmless because we do 415 * not permit rendezvous action routines to schedule threads, 416 * and thus td_owepreempt should never transition from 0 to 1 417 * during this routine. 418 */ 419 td = curthread; 420 td->td_critnest++; 421 #ifdef INVARIANTS 422 owepreempt = td->td_owepreempt; 423 #endif 424 425 /* 426 * If requested, run a setup function before the main action 427 * function. Ensure all CPUs have completed the setup 428 * function before moving on to the action function. 429 */ 430 if (local_setup_func != smp_no_rendevous_barrier) { 431 if (smp_rv_setup_func != NULL) 432 smp_rv_setup_func(smp_rv_func_arg); 433 atomic_add_int(&smp_rv_waiters[1], 1); 434 while (smp_rv_waiters[1] < smp_rv_ncpus) 435 cpu_spinwait(); 436 } 437 438 if (local_action_func != NULL) 439 local_action_func(local_func_arg); 440 441 if (local_teardown_func != smp_no_rendevous_barrier) { 442 /* 443 * Signal that the main action has been completed. If a 444 * full exit rendezvous is requested, then all CPUs will 445 * wait here until all CPUs have finished the main action. 446 */ 447 atomic_add_int(&smp_rv_waiters[2], 1); 448 while (smp_rv_waiters[2] < smp_rv_ncpus) 449 cpu_spinwait(); 450 451 if (local_teardown_func != NULL) 452 local_teardown_func(local_func_arg); 453 } 454 455 /* 456 * Signal that the rendezvous is fully completed by this CPU. 457 * This means that no member of smp_rv_* pseudo-structure will be 458 * accessed by this target CPU after this point; in particular, 459 * memory pointed by smp_rv_func_arg. 460 */ 461 atomic_add_int(&smp_rv_waiters[3], 1); 462 463 td->td_critnest--; 464 KASSERT(owepreempt == td->td_owepreempt, 465 ("rendezvous action changed td_owepreempt")); 466 } 467 468 void 469 smp_rendezvous_cpus(cpuset_t map, 470 void (* setup_func)(void *), 471 void (* action_func)(void *), 472 void (* teardown_func)(void *), 473 void *arg) 474 { 475 int curcpumap, i, ncpus = 0; 476 477 /* Look comments in the !SMP case. */ 478 if (!smp_started) { 479 spinlock_enter(); 480 if (setup_func != NULL) 481 setup_func(arg); 482 if (action_func != NULL) 483 action_func(arg); 484 if (teardown_func != NULL) 485 teardown_func(arg); 486 spinlock_exit(); 487 return; 488 } 489 490 CPU_FOREACH(i) { 491 if (CPU_ISSET(i, &map)) 492 ncpus++; 493 } 494 if (ncpus == 0) 495 panic("ncpus is 0 with non-zero map"); 496 497 mtx_lock_spin(&smp_ipi_mtx); 498 499 /* Pass rendezvous parameters via global variables. */ 500 smp_rv_ncpus = ncpus; 501 smp_rv_setup_func = setup_func; 502 smp_rv_action_func = action_func; 503 smp_rv_teardown_func = teardown_func; 504 smp_rv_func_arg = arg; 505 smp_rv_waiters[1] = 0; 506 smp_rv_waiters[2] = 0; 507 smp_rv_waiters[3] = 0; 508 atomic_store_rel_int(&smp_rv_waiters[0], 0); 509 510 /* 511 * Signal other processors, which will enter the IPI with 512 * interrupts off. 513 */ 514 curcpumap = CPU_ISSET(curcpu, &map); 515 CPU_CLR(curcpu, &map); 516 ipi_selected(map, IPI_RENDEZVOUS); 517 518 /* Check if the current CPU is in the map */ 519 if (curcpumap != 0) 520 smp_rendezvous_action(); 521 522 /* 523 * Ensure that the master CPU waits for all the other 524 * CPUs to finish the rendezvous, so that smp_rv_* 525 * pseudo-structure and the arg are guaranteed to not 526 * be in use. 527 */ 528 while (atomic_load_acq_int(&smp_rv_waiters[3]) < ncpus) 529 cpu_spinwait(); 530 531 mtx_unlock_spin(&smp_ipi_mtx); 532 } 533 534 void 535 smp_rendezvous(void (* setup_func)(void *), 536 void (* action_func)(void *), 537 void (* teardown_func)(void *), 538 void *arg) 539 { 540 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); 541 } 542 543 static struct cpu_group group[MAXCPU]; 544 545 struct cpu_group * 546 smp_topo(void) 547 { 548 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 549 struct cpu_group *top; 550 551 /* 552 * Check for a fake topology request for debugging purposes. 553 */ 554 switch (smp_topology) { 555 case 1: 556 /* Dual core with no sharing. */ 557 top = smp_topo_1level(CG_SHARE_NONE, 2, 0); 558 break; 559 case 2: 560 /* No topology, all cpus are equal. */ 561 top = smp_topo_none(); 562 break; 563 case 3: 564 /* Dual core with shared L2. */ 565 top = smp_topo_1level(CG_SHARE_L2, 2, 0); 566 break; 567 case 4: 568 /* quad core, shared l3 among each package, private l2. */ 569 top = smp_topo_1level(CG_SHARE_L3, 4, 0); 570 break; 571 case 5: 572 /* quad core, 2 dualcore parts on each package share l2. */ 573 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); 574 break; 575 case 6: 576 /* Single-core 2xHTT */ 577 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); 578 break; 579 case 7: 580 /* quad core with a shared l3, 8 threads sharing L2. */ 581 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, 582 CG_FLAG_SMT); 583 break; 584 default: 585 /* Default, ask the system what it wants. */ 586 top = cpu_topo(); 587 break; 588 } 589 /* 590 * Verify the returned topology. 591 */ 592 if (top->cg_count != mp_ncpus) 593 panic("Built bad topology at %p. CPU count %d != %d", 594 top, top->cg_count, mp_ncpus); 595 if (CPU_CMP(&top->cg_mask, &all_cpus)) 596 panic("Built bad topology at %p. CPU mask (%s) != (%s)", 597 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), 598 cpusetobj_strprint(cpusetbuf2, &all_cpus)); 599 return (top); 600 } 601 602 struct cpu_group * 603 smp_topo_none(void) 604 { 605 struct cpu_group *top; 606 607 top = &group[0]; 608 top->cg_parent = NULL; 609 top->cg_child = NULL; 610 top->cg_mask = all_cpus; 611 top->cg_count = mp_ncpus; 612 top->cg_children = 0; 613 top->cg_level = CG_SHARE_NONE; 614 top->cg_flags = 0; 615 616 return (top); 617 } 618 619 static int 620 smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, 621 int count, int flags, int start) 622 { 623 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 624 cpuset_t mask; 625 int i; 626 627 CPU_ZERO(&mask); 628 for (i = 0; i < count; i++, start++) 629 CPU_SET(start, &mask); 630 child->cg_parent = parent; 631 child->cg_child = NULL; 632 child->cg_children = 0; 633 child->cg_level = share; 634 child->cg_count = count; 635 child->cg_flags = flags; 636 child->cg_mask = mask; 637 parent->cg_children++; 638 for (; parent != NULL; parent = parent->cg_parent) { 639 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) 640 panic("Duplicate children in %p. mask (%s) child (%s)", 641 parent, 642 cpusetobj_strprint(cpusetbuf, &parent->cg_mask), 643 cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); 644 CPU_OR(&parent->cg_mask, &child->cg_mask); 645 parent->cg_count += child->cg_count; 646 } 647 648 return (start); 649 } 650 651 struct cpu_group * 652 smp_topo_1level(int share, int count, int flags) 653 { 654 struct cpu_group *child; 655 struct cpu_group *top; 656 int packages; 657 int cpu; 658 int i; 659 660 cpu = 0; 661 top = &group[0]; 662 packages = mp_ncpus / count; 663 top->cg_child = child = &group[1]; 664 top->cg_level = CG_SHARE_NONE; 665 for (i = 0; i < packages; i++, child++) 666 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); 667 return (top); 668 } 669 670 struct cpu_group * 671 smp_topo_2level(int l2share, int l2count, int l1share, int l1count, 672 int l1flags) 673 { 674 struct cpu_group *top; 675 struct cpu_group *l1g; 676 struct cpu_group *l2g; 677 int cpu; 678 int i; 679 int j; 680 681 cpu = 0; 682 top = &group[0]; 683 l2g = &group[1]; 684 top->cg_child = l2g; 685 top->cg_level = CG_SHARE_NONE; 686 top->cg_children = mp_ncpus / (l2count * l1count); 687 l1g = l2g + top->cg_children; 688 for (i = 0; i < top->cg_children; i++, l2g++) { 689 l2g->cg_parent = top; 690 l2g->cg_child = l1g; 691 l2g->cg_level = l2share; 692 for (j = 0; j < l2count; j++, l1g++) 693 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, 694 l1flags, cpu); 695 } 696 return (top); 697 } 698 699 700 struct cpu_group * 701 smp_topo_find(struct cpu_group *top, int cpu) 702 { 703 struct cpu_group *cg; 704 cpuset_t mask; 705 int children; 706 int i; 707 708 CPU_SETOF(cpu, &mask); 709 cg = top; 710 for (;;) { 711 if (!CPU_OVERLAP(&cg->cg_mask, &mask)) 712 return (NULL); 713 if (cg->cg_children == 0) 714 return (cg); 715 children = cg->cg_children; 716 for (i = 0, cg = cg->cg_child; i < children; cg++, i++) 717 if (CPU_OVERLAP(&cg->cg_mask, &mask)) 718 break; 719 } 720 return (NULL); 721 } 722 #else /* !SMP */ 723 724 void 725 smp_rendezvous_cpus(cpuset_t map, 726 void (*setup_func)(void *), 727 void (*action_func)(void *), 728 void (*teardown_func)(void *), 729 void *arg) 730 { 731 /* 732 * In the !SMP case we just need to ensure the same initial conditions 733 * as the SMP case. 734 */ 735 spinlock_enter(); 736 if (setup_func != NULL) 737 setup_func(arg); 738 if (action_func != NULL) 739 action_func(arg); 740 if (teardown_func != NULL) 741 teardown_func(arg); 742 spinlock_exit(); 743 } 744 745 void 746 smp_rendezvous(void (*setup_func)(void *), 747 void (*action_func)(void *), 748 void (*teardown_func)(void *), 749 void *arg) 750 { 751 752 /* Look comments in the smp_rendezvous_cpus() case. */ 753 spinlock_enter(); 754 if (setup_func != NULL) 755 setup_func(arg); 756 if (action_func != NULL) 757 action_func(arg); 758 if (teardown_func != NULL) 759 teardown_func(arg); 760 spinlock_exit(); 761 } 762 763 /* 764 * Provide dummy SMP support for UP kernels. Modules that need to use SMP 765 * APIs will still work using this dummy support. 766 */ 767 static void 768 mp_setvariables_for_up(void *dummy) 769 { 770 mp_ncpus = 1; 771 mp_maxid = PCPU_GET(cpuid); 772 CPU_SETOF(mp_maxid, &all_cpus); 773 KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero")); 774 } 775 SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST, 776 mp_setvariables_for_up, NULL); 777 #endif /* SMP */ 778 779 void 780 smp_no_rendevous_barrier(void *dummy) 781 { 782 #ifdef SMP 783 KASSERT((!smp_started),("smp_no_rendevous called and smp is started")); 784 #endif 785 } 786 787 /* 788 * Wait specified idle threads to switch once. This ensures that even 789 * preempted threads have cycled through the switch function once, 790 * exiting their codepaths. This allows us to change global pointers 791 * with no other synchronization. 792 */ 793 int 794 quiesce_cpus(cpuset_t map, const char *wmesg, int prio) 795 { 796 struct pcpu *pcpu; 797 u_int gen[MAXCPU]; 798 int error; 799 int cpu; 800 801 error = 0; 802 for (cpu = 0; cpu <= mp_maxid; cpu++) { 803 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 804 continue; 805 pcpu = pcpu_find(cpu); 806 gen[cpu] = pcpu->pc_idlethread->td_generation; 807 } 808 for (cpu = 0; cpu <= mp_maxid; cpu++) { 809 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 810 continue; 811 pcpu = pcpu_find(cpu); 812 thread_lock(curthread); 813 sched_bind(curthread, cpu); 814 thread_unlock(curthread); 815 while (gen[cpu] == pcpu->pc_idlethread->td_generation) { 816 error = tsleep(quiesce_cpus, prio, wmesg, 1); 817 if (error != EWOULDBLOCK) 818 goto out; 819 error = 0; 820 } 821 } 822 out: 823 thread_lock(curthread); 824 sched_unbind(curthread); 825 thread_unlock(curthread); 826 827 return (error); 828 } 829 830 int 831 quiesce_all_cpus(const char *wmesg, int prio) 832 { 833 834 return quiesce_cpus(all_cpus, wmesg, prio); 835 } 836 837 /* Extra care is taken with this sysctl because the data type is volatile */ 838 static int 839 sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS) 840 { 841 int error, active; 842 843 active = smp_started; 844 error = SYSCTL_OUT(req, &active, sizeof(active)); 845 return (error); 846 } 847 848