1/*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2001, John Baldwin <jhb@FreeBSD.org>. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28/* 29 * This module holds the global variables and machine independent functions 30 * used for the kernel SMP support. 31 */ 32 33#include <sys/cdefs.h> 34__FBSDID("$FreeBSD$"); 35 36#include <sys/param.h> 37#include <sys/systm.h> 38#include <sys/kernel.h> 39#include <sys/ktr.h> 40#include <sys/proc.h> 41#include <sys/bus.h> 42#include <sys/lock.h> 43#include <sys/malloc.h> 44#include <sys/mutex.h> 45#include <sys/pcpu.h> 46#include <sys/sched.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 56MALLOC_DEFINE(M_TOPO, "toponodes", "SMP topology data"); 57 58volatile cpuset_t stopped_cpus; 59volatile cpuset_t started_cpus; 60volatile cpuset_t suspended_cpus; 61cpuset_t hlt_cpus_mask; 62cpuset_t logical_cpus_mask; 63 64void (*cpustop_restartfunc)(void); 65#endif 66 67static int sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS); 68 69/* This is used in modules that need to work in both SMP and UP. */ 70cpuset_t all_cpus; 71 72int mp_ncpus; 73/* export this for libkvm consumers. */ 74int mp_maxcpus = MAXCPU; 75 76volatile int smp_started; 77u_int mp_maxid; 78 79static SYSCTL_NODE(_kern, OID_AUTO, smp, 80 CTLFLAG_RD | CTLFLAG_CAPRD | CTLFLAG_MPSAFE, NULL, 81 "Kernel SMP"); 82 83SYSCTL_INT(_kern_smp, OID_AUTO, maxid, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxid, 0, 84 "Max CPU ID."); 85 86SYSCTL_INT(_kern_smp, OID_AUTO, maxcpus, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxcpus, 87 0, "Max number of CPUs that the system was compiled for."); 88 89SYSCTL_PROC(_kern_smp, OID_AUTO, active, CTLFLAG_RD|CTLTYPE_INT|CTLFLAG_MPSAFE, 90 NULL, 0, sysctl_kern_smp_active, "I", 91 "Indicates system is running in SMP mode"); 92 93int smp_disabled = 0; /* has smp been disabled? */ 94SYSCTL_INT(_kern_smp, OID_AUTO, disabled, CTLFLAG_RDTUN|CTLFLAG_CAPRD, 95 &smp_disabled, 0, "SMP has been disabled from the loader"); 96 97int smp_cpus = 1; /* how many cpu's running */ 98SYSCTL_INT(_kern_smp, OID_AUTO, cpus, CTLFLAG_RD|CTLFLAG_CAPRD, &smp_cpus, 0, 99 "Number of CPUs online"); 100 101int smp_threads_per_core = 1; /* how many SMT threads are running per core */ 102SYSCTL_INT(_kern_smp, OID_AUTO, threads_per_core, CTLFLAG_RD|CTLFLAG_CAPRD, 103 &smp_threads_per_core, 0, "Number of SMT threads online per core"); 104 105int mp_ncores = -1; /* how many physical cores running */ 106SYSCTL_INT(_kern_smp, OID_AUTO, cores, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_ncores, 0, 107 "Number of physical cores online"); 108 109int smp_topology = 0; /* Which topology we're using. */ 110SYSCTL_INT(_kern_smp, OID_AUTO, topology, CTLFLAG_RDTUN, &smp_topology, 0, 111 "Topology override setting; 0 is default provided by hardware."); 112 113#ifdef SMP 114/* Enable forwarding of a signal to a process running on a different CPU */ 115static int forward_signal_enabled = 1; 116SYSCTL_INT(_kern_smp, OID_AUTO, forward_signal_enabled, CTLFLAG_RW, 117 &forward_signal_enabled, 0, 118 "Forwarding of a signal to a process on a different CPU"); 119 120/* Variables needed for SMP rendezvous. */ 121static volatile int smp_rv_ncpus; 122static void (*volatile smp_rv_setup_func)(void *arg); 123static void (*volatile smp_rv_action_func)(void *arg); 124static void (*volatile smp_rv_teardown_func)(void *arg); 125static void *volatile smp_rv_func_arg; 126static volatile int smp_rv_waiters[4]; 127 128/* 129 * Shared mutex to restrict busywaits between smp_rendezvous() and 130 * smp(_targeted)_tlb_shootdown(). A deadlock occurs if both of these 131 * functions trigger at once and cause multiple CPUs to busywait with 132 * interrupts disabled. 133 */ 134struct mtx smp_ipi_mtx; 135 136/* 137 * Let the MD SMP code initialize mp_maxid very early if it can. 138 */ 139static void 140mp_setmaxid(void *dummy) 141{ 142 143 cpu_mp_setmaxid(); 144 145 KASSERT(mp_ncpus >= 1, ("%s: CPU count < 1", __func__)); 146 KASSERT(mp_ncpus > 1 || mp_maxid == 0, 147 ("%s: one CPU but mp_maxid is not zero", __func__)); 148 KASSERT(mp_maxid >= mp_ncpus - 1, 149 ("%s: counters out of sync: max %d, count %d", __func__, 150 mp_maxid, mp_ncpus)); 151} 152SYSINIT(cpu_mp_setmaxid, SI_SUB_TUNABLES, SI_ORDER_FIRST, mp_setmaxid, NULL); 153 154/* 155 * Call the MD SMP initialization code. 156 */ 157static void 158mp_start(void *dummy) 159{ 160 161 mtx_init(&smp_ipi_mtx, "smp rendezvous", NULL, MTX_SPIN); 162 163 /* Probe for MP hardware. */ 164 if (smp_disabled != 0 || cpu_mp_probe() == 0) { 165 mp_ncores = 1; 166 mp_ncpus = 1; 167 CPU_SETOF(PCPU_GET(cpuid), &all_cpus); 168 return; 169 } 170 171 cpu_mp_start(); 172 printf("FreeBSD/SMP: Multiprocessor System Detected: %d CPUs\n", 173 mp_ncpus); 174 175 /* Provide a default for most architectures that don't have SMT/HTT. */ 176 if (mp_ncores < 0) 177 mp_ncores = mp_ncpus; 178 179 cpu_mp_announce(); 180} 181SYSINIT(cpu_mp, SI_SUB_CPU, SI_ORDER_THIRD, mp_start, NULL); 182 183void 184forward_signal(struct thread *td) 185{ 186 int id; 187 188 /* 189 * signotify() has already set TDF_ASTPENDING and TDF_NEEDSIGCHECK on 190 * this thread, so all we need to do is poke it if it is currently 191 * executing so that it executes ast(). 192 */ 193 THREAD_LOCK_ASSERT(td, MA_OWNED); 194 KASSERT(TD_IS_RUNNING(td), 195 ("forward_signal: thread is not TDS_RUNNING")); 196 197 CTR1(KTR_SMP, "forward_signal(%p)", td->td_proc); 198 199 if (!smp_started || cold || KERNEL_PANICKED()) 200 return; 201 if (!forward_signal_enabled) 202 return; 203 204 /* No need to IPI ourself. */ 205 if (td == curthread) 206 return; 207 208 id = td->td_oncpu; 209 if (id == NOCPU) 210 return; 211 ipi_cpu(id, IPI_AST); 212} 213 214/* 215 * When called the executing CPU will send an IPI to all other CPUs 216 * requesting that they halt execution. 217 * 218 * Usually (but not necessarily) called with 'other_cpus' as its arg. 219 * 220 * - Signals all CPUs in map to stop. 221 * - Waits for each to stop. 222 * 223 * Returns: 224 * -1: error 225 * 0: NA 226 * 1: ok 227 * 228 */ 229#if defined(__amd64__) || defined(__i386__) 230#define X86 1 231#else 232#define X86 0 233#endif 234static int 235generic_stop_cpus(cpuset_t map, u_int type) 236{ 237#ifdef KTR 238 char cpusetbuf[CPUSETBUFSIZ]; 239#endif 240 static volatile u_int stopping_cpu = NOCPU; 241 int i; 242 volatile cpuset_t *cpus; 243 244 KASSERT( 245 type == IPI_STOP || type == IPI_STOP_HARD 246#if X86 247 || type == IPI_SUSPEND 248#endif 249 , ("%s: invalid stop type", __func__)); 250 251 if (!smp_started) 252 return (0); 253 254 CTR2(KTR_SMP, "stop_cpus(%s) with %u type", 255 cpusetobj_strprint(cpusetbuf, &map), type); 256 257#if X86 258 /* 259 * When suspending, ensure there are are no IPIs in progress. 260 * IPIs that have been issued, but not yet delivered (e.g. 261 * not pending on a vCPU when running under virtualization) 262 * will be lost, violating FreeBSD's assumption of reliable 263 * IPI delivery. 264 */ 265 if (type == IPI_SUSPEND) 266 mtx_lock_spin(&smp_ipi_mtx); 267#endif 268 269#if X86 270 if (!nmi_is_broadcast || nmi_kdb_lock == 0) { 271#endif 272 if (stopping_cpu != PCPU_GET(cpuid)) 273 while (atomic_cmpset_int(&stopping_cpu, NOCPU, 274 PCPU_GET(cpuid)) == 0) 275 while (stopping_cpu != NOCPU) 276 cpu_spinwait(); /* spin */ 277 278 /* send the stop IPI to all CPUs in map */ 279 ipi_selected(map, type); 280#if X86 281 } 282#endif 283 284#if X86 285 if (type == IPI_SUSPEND) 286 cpus = &suspended_cpus; 287 else 288#endif 289 cpus = &stopped_cpus; 290 291 i = 0; 292 while (!CPU_SUBSET(cpus, &map)) { 293 /* spin */ 294 cpu_spinwait(); 295 i++; 296 if (i == 100000000) { 297 printf("timeout stopping cpus\n"); 298 break; 299 } 300 } 301 302#if X86 303 if (type == IPI_SUSPEND) 304 mtx_unlock_spin(&smp_ipi_mtx); 305#endif 306 307 stopping_cpu = NOCPU; 308 return (1); 309} 310 311int 312stop_cpus(cpuset_t map) 313{ 314 315 return (generic_stop_cpus(map, IPI_STOP)); 316} 317 318int 319stop_cpus_hard(cpuset_t map) 320{ 321 322 return (generic_stop_cpus(map, IPI_STOP_HARD)); 323} 324 325#if X86 326int 327suspend_cpus(cpuset_t map) 328{ 329 330 return (generic_stop_cpus(map, IPI_SUSPEND)); 331} 332#endif 333 334/* 335 * Called by a CPU to restart stopped CPUs. 336 * 337 * Usually (but not necessarily) called with 'stopped_cpus' as its arg. 338 * 339 * - Signals all CPUs in map to restart. 340 * - Waits for each to restart. 341 * 342 * Returns: 343 * -1: error 344 * 0: NA 345 * 1: ok 346 */ 347static int 348generic_restart_cpus(cpuset_t map, u_int type) 349{ 350#ifdef KTR 351 char cpusetbuf[CPUSETBUFSIZ]; 352#endif 353 volatile cpuset_t *cpus; 354 355#if X86 356 KASSERT(type == IPI_STOP || type == IPI_STOP_HARD 357 || type == IPI_SUSPEND, ("%s: invalid stop type", __func__)); 358 359 if (!smp_started) 360 return (0); 361 362 CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); 363 364 if (type == IPI_SUSPEND) 365 cpus = &resuming_cpus; 366 else 367 cpus = &stopped_cpus; 368 369 /* signal other cpus to restart */ 370 if (type == IPI_SUSPEND) 371 CPU_COPY_STORE_REL(&map, &toresume_cpus); 372 else 373 CPU_COPY_STORE_REL(&map, &started_cpus); 374 375 /* 376 * Wake up any CPUs stopped with MWAIT. From MI code we can't tell if 377 * MONITOR/MWAIT is enabled, but the potentially redundant writes are 378 * relatively inexpensive. 379 */ 380 if (type == IPI_STOP) { 381 struct monitorbuf *mb; 382 u_int id; 383 384 CPU_FOREACH(id) { 385 if (!CPU_ISSET(id, &map)) 386 continue; 387 388 mb = &pcpu_find(id)->pc_monitorbuf; 389 atomic_store_int(&mb->stop_state, 390 MONITOR_STOPSTATE_RUNNING); 391 } 392 } 393 394 if (!nmi_is_broadcast || nmi_kdb_lock == 0) { 395 /* wait for each to clear its bit */ 396 while (CPU_OVERLAP(cpus, &map)) 397 cpu_spinwait(); 398 } 399#else /* !X86 */ 400 KASSERT(type == IPI_STOP || type == IPI_STOP_HARD, 401 ("%s: invalid stop type", __func__)); 402 403 if (!smp_started) 404 return (0); 405 406 CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); 407 408 cpus = &stopped_cpus; 409 410 /* signal other cpus to restart */ 411 CPU_COPY_STORE_REL(&map, &started_cpus); 412 413 /* wait for each to clear its bit */ 414 while (CPU_OVERLAP(cpus, &map)) 415 cpu_spinwait(); 416#endif 417 return (1); 418} 419 420int 421restart_cpus(cpuset_t map) 422{ 423 424 return (generic_restart_cpus(map, IPI_STOP)); 425} 426 427#if X86 428int 429resume_cpus(cpuset_t map) 430{ 431 432 return (generic_restart_cpus(map, IPI_SUSPEND)); 433} 434#endif 435#undef X86 436 437/* 438 * All-CPU rendezvous. CPUs are signalled, all execute the setup function 439 * (if specified), rendezvous, execute the action function (if specified), 440 * rendezvous again, execute the teardown function (if specified), and then 441 * resume. 442 * 443 * Note that the supplied external functions _must_ be reentrant and aware 444 * that they are running in parallel and in an unknown lock context. 445 */ 446void 447smp_rendezvous_action(void) 448{ 449 struct thread *td; 450 void *local_func_arg; 451 void (*local_setup_func)(void*); 452 void (*local_action_func)(void*); 453 void (*local_teardown_func)(void*); 454#ifdef INVARIANTS 455 int owepreempt; 456#endif 457 458 /* Ensure we have up-to-date values. */ 459 atomic_add_acq_int(&smp_rv_waiters[0], 1); 460 while (smp_rv_waiters[0] < smp_rv_ncpus) 461 cpu_spinwait(); 462 463 /* Fetch rendezvous parameters after acquire barrier. */ 464 local_func_arg = smp_rv_func_arg; 465 local_setup_func = smp_rv_setup_func; 466 local_action_func = smp_rv_action_func; 467 local_teardown_func = smp_rv_teardown_func; 468 469 /* 470 * Use a nested critical section to prevent any preemptions 471 * from occurring during a rendezvous action routine. 472 * Specifically, if a rendezvous handler is invoked via an IPI 473 * and the interrupted thread was in the critical_exit() 474 * function after setting td_critnest to 0 but before 475 * performing a deferred preemption, this routine can be 476 * invoked with td_critnest set to 0 and td_owepreempt true. 477 * In that case, a critical_exit() during the rendezvous 478 * action would trigger a preemption which is not permitted in 479 * a rendezvous action. To fix this, wrap all of the 480 * rendezvous action handlers in a critical section. We 481 * cannot use a regular critical section however as having 482 * critical_exit() preempt from this routine would also be 483 * problematic (the preemption must not occur before the IPI 484 * has been acknowledged via an EOI). Instead, we 485 * intentionally ignore td_owepreempt when leaving the 486 * critical section. This should be harmless because we do 487 * not permit rendezvous action routines to schedule threads, 488 * and thus td_owepreempt should never transition from 0 to 1 489 * during this routine. 490 */ 491 td = curthread; 492 td->td_critnest++; 493#ifdef INVARIANTS 494 owepreempt = td->td_owepreempt; 495#endif 496 497 /* 498 * If requested, run a setup function before the main action 499 * function. Ensure all CPUs have completed the setup 500 * function before moving on to the action function. 501 */ 502 if (local_setup_func != smp_no_rendezvous_barrier) { 503 if (smp_rv_setup_func != NULL) 504 smp_rv_setup_func(smp_rv_func_arg); 505 atomic_add_int(&smp_rv_waiters[1], 1); 506 while (smp_rv_waiters[1] < smp_rv_ncpus) 507 cpu_spinwait(); 508 } 509 510 if (local_action_func != NULL) 511 local_action_func(local_func_arg); 512 513 if (local_teardown_func != smp_no_rendezvous_barrier) { 514 /* 515 * Signal that the main action has been completed. If a 516 * full exit rendezvous is requested, then all CPUs will 517 * wait here until all CPUs have finished the main action. 518 */ 519 atomic_add_int(&smp_rv_waiters[2], 1); 520 while (smp_rv_waiters[2] < smp_rv_ncpus) 521 cpu_spinwait(); 522 523 if (local_teardown_func != NULL) 524 local_teardown_func(local_func_arg); 525 } 526 527 /* 528 * Signal that the rendezvous is fully completed by this CPU. 529 * This means that no member of smp_rv_* pseudo-structure will be 530 * accessed by this target CPU after this point; in particular, 531 * memory pointed by smp_rv_func_arg. 532 * 533 * The release semantic ensures that all accesses performed by 534 * the current CPU are visible when smp_rendezvous_cpus() 535 * returns, by synchronizing with the 536 * atomic_load_acq_int(&smp_rv_waiters[3]). 537 */ 538 atomic_add_rel_int(&smp_rv_waiters[3], 1); 539 540 td->td_critnest--; 541 KASSERT(owepreempt == td->td_owepreempt, 542 ("rendezvous action changed td_owepreempt")); 543} 544 545void 546smp_rendezvous_cpus(cpuset_t map, 547 void (* setup_func)(void *), 548 void (* action_func)(void *), 549 void (* teardown_func)(void *), 550 void *arg) 551{ 552 int curcpumap, i, ncpus = 0; 553 554 /* See comments in the !SMP case. */ 555 if (!smp_started) { 556 spinlock_enter(); 557 if (setup_func != NULL) 558 setup_func(arg); 559 if (action_func != NULL) 560 action_func(arg); 561 if (teardown_func != NULL) 562 teardown_func(arg); 563 spinlock_exit(); 564 return; 565 } 566 567 /* 568 * Make sure we come here with interrupts enabled. Otherwise we 569 * livelock if smp_ipi_mtx is owned by a thread which sent us an IPI. 570 */ 571 MPASS(curthread->td_md.md_spinlock_count == 0); 572 573 CPU_FOREACH(i) { 574 if (CPU_ISSET(i, &map)) 575 ncpus++; 576 } 577 if (ncpus == 0) 578 panic("ncpus is 0 with non-zero map"); 579 580 mtx_lock_spin(&smp_ipi_mtx); 581 582 /* Pass rendezvous parameters via global variables. */ 583 smp_rv_ncpus = ncpus; 584 smp_rv_setup_func = setup_func; 585 smp_rv_action_func = action_func; 586 smp_rv_teardown_func = teardown_func; 587 smp_rv_func_arg = arg; 588 smp_rv_waiters[1] = 0; 589 smp_rv_waiters[2] = 0; 590 smp_rv_waiters[3] = 0; 591 atomic_store_rel_int(&smp_rv_waiters[0], 0); 592 593 /* 594 * Signal other processors, which will enter the IPI with 595 * interrupts off. 596 */ 597 curcpumap = CPU_ISSET(curcpu, &map); 598 CPU_CLR(curcpu, &map); 599 ipi_selected(map, IPI_RENDEZVOUS); 600 601 /* Check if the current CPU is in the map */ 602 if (curcpumap != 0) 603 smp_rendezvous_action(); 604 605 /* 606 * Ensure that the master CPU waits for all the other 607 * CPUs to finish the rendezvous, so that smp_rv_* 608 * pseudo-structure and the arg are guaranteed to not 609 * be in use. 610 * 611 * Load acquire synchronizes with the release add in 612 * smp_rendezvous_action(), which ensures that our caller sees 613 * all memory actions done by the called functions on other 614 * CPUs. 615 */ 616 while (atomic_load_acq_int(&smp_rv_waiters[3]) < ncpus) 617 cpu_spinwait(); 618 619 mtx_unlock_spin(&smp_ipi_mtx); 620} 621 622void 623smp_rendezvous(void (* setup_func)(void *), 624 void (* action_func)(void *), 625 void (* teardown_func)(void *), 626 void *arg) 627{ 628 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); 629} 630 631static struct cpu_group group[MAXCPU * MAX_CACHE_LEVELS + 1]; 632 633struct cpu_group * 634smp_topo(void) 635{ 636 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 637 struct cpu_group *top; 638 639 /* 640 * Check for a fake topology request for debugging purposes. 641 */ 642 switch (smp_topology) { 643 case 1: 644 /* Dual core with no sharing. */ 645 top = smp_topo_1level(CG_SHARE_NONE, 2, 0); 646 break; 647 case 2: 648 /* No topology, all cpus are equal. */ 649 top = smp_topo_none(); 650 break; 651 case 3: 652 /* Dual core with shared L2. */ 653 top = smp_topo_1level(CG_SHARE_L2, 2, 0); 654 break; 655 case 4: 656 /* quad core, shared l3 among each package, private l2. */ 657 top = smp_topo_1level(CG_SHARE_L3, 4, 0); 658 break; 659 case 5: 660 /* quad core, 2 dualcore parts on each package share l2. */ 661 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); 662 break; 663 case 6: 664 /* Single-core 2xHTT */ 665 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); 666 break; 667 case 7: 668 /* quad core with a shared l3, 8 threads sharing L2. */ 669 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, 670 CG_FLAG_SMT); 671 break; 672 default: 673 /* Default, ask the system what it wants. */ 674 top = cpu_topo(); 675 break; 676 } 677 /* 678 * Verify the returned topology. 679 */ 680 if (top->cg_count != mp_ncpus) 681 panic("Built bad topology at %p. CPU count %d != %d", 682 top, top->cg_count, mp_ncpus); 683 if (CPU_CMP(&top->cg_mask, &all_cpus)) 684 panic("Built bad topology at %p. CPU mask (%s) != (%s)", 685 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), 686 cpusetobj_strprint(cpusetbuf2, &all_cpus)); 687 688 /* 689 * Collapse nonsense levels that may be created out of convenience by 690 * the MD layers. They cause extra work in the search functions. 691 */ 692 while (top->cg_children == 1) { 693 top = &top->cg_child[0]; 694 top->cg_parent = NULL; 695 } 696 return (top); 697} 698 699struct cpu_group * 700smp_topo_alloc(u_int count) 701{ 702 static u_int index; 703 u_int curr; 704 705 curr = index; 706 index += count; 707 return (&group[curr]); 708} 709 710struct cpu_group * 711smp_topo_none(void) 712{ 713 struct cpu_group *top; 714 715 top = &group[0]; 716 top->cg_parent = NULL; 717 top->cg_child = NULL; 718 top->cg_mask = all_cpus; 719 top->cg_count = mp_ncpus; 720 top->cg_children = 0; 721 top->cg_level = CG_SHARE_NONE; 722 top->cg_flags = 0; 723 724 return (top); 725} 726 727static int 728smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, 729 int count, int flags, int start) 730{ 731 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 732 cpuset_t mask; 733 int i; 734 735 CPU_ZERO(&mask); 736 for (i = 0; i < count; i++, start++) 737 CPU_SET(start, &mask); 738 child->cg_parent = parent; 739 child->cg_child = NULL; 740 child->cg_children = 0; 741 child->cg_level = share; 742 child->cg_count = count; 743 child->cg_flags = flags; 744 child->cg_mask = mask; 745 parent->cg_children++; 746 for (; parent != NULL; parent = parent->cg_parent) { 747 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) 748 panic("Duplicate children in %p. mask (%s) child (%s)", 749 parent, 750 cpusetobj_strprint(cpusetbuf, &parent->cg_mask), 751 cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); 752 CPU_OR(&parent->cg_mask, &child->cg_mask); 753 parent->cg_count += child->cg_count; 754 } 755 756 return (start); 757} 758 759struct cpu_group * 760smp_topo_1level(int share, int count, int flags) 761{ 762 struct cpu_group *child; 763 struct cpu_group *top; 764 int packages; 765 int cpu; 766 int i; 767 768 cpu = 0; 769 top = &group[0]; 770 packages = mp_ncpus / count; 771 top->cg_child = child = &group[1]; 772 top->cg_level = CG_SHARE_NONE; 773 for (i = 0; i < packages; i++, child++) 774 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); 775 return (top); 776} 777 778struct cpu_group * 779smp_topo_2level(int l2share, int l2count, int l1share, int l1count, 780 int l1flags) 781{ 782 struct cpu_group *top; 783 struct cpu_group *l1g; 784 struct cpu_group *l2g; 785 int cpu; 786 int i; 787 int j; 788 789 cpu = 0; 790 top = &group[0]; 791 l2g = &group[1]; 792 top->cg_child = l2g; 793 top->cg_level = CG_SHARE_NONE; 794 top->cg_children = mp_ncpus / (l2count * l1count); 795 l1g = l2g + top->cg_children; 796 for (i = 0; i < top->cg_children; i++, l2g++) { 797 l2g->cg_parent = top; 798 l2g->cg_child = l1g; 799 l2g->cg_level = l2share; 800 for (j = 0; j < l2count; j++, l1g++) 801 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, 802 l1flags, cpu); 803 } 804 return (top); 805} 806 807struct cpu_group * 808smp_topo_find(struct cpu_group *top, int cpu) 809{ 810 struct cpu_group *cg; 811 cpuset_t mask; 812 int children; 813 int i; 814 815 CPU_SETOF(cpu, &mask); 816 cg = top; 817 for (;;) { 818 if (!CPU_OVERLAP(&cg->cg_mask, &mask)) 819 return (NULL); 820 if (cg->cg_children == 0) 821 return (cg); 822 children = cg->cg_children; 823 for (i = 0, cg = cg->cg_child; i < children; cg++, i++) 824 if (CPU_OVERLAP(&cg->cg_mask, &mask)) 825 break; 826 } 827 return (NULL); 828} 829#else /* !SMP */ 830 831void 832smp_rendezvous_cpus(cpuset_t map, 833 void (*setup_func)(void *), 834 void (*action_func)(void *), 835 void (*teardown_func)(void *), 836 void *arg) 837{ 838 /* 839 * In the !SMP case we just need to ensure the same initial conditions 840 * as the SMP case. 841 */ 842 spinlock_enter(); 843 if (setup_func != NULL) 844 setup_func(arg); 845 if (action_func != NULL) 846 action_func(arg); 847 if (teardown_func != NULL) 848 teardown_func(arg); 849 spinlock_exit(); 850} 851 852void 853smp_rendezvous(void (*setup_func)(void *), 854 void (*action_func)(void *), 855 void (*teardown_func)(void *), 856 void *arg) 857{ 858 859 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, 860 arg); 861} 862 863/* 864 * Provide dummy SMP support for UP kernels. Modules that need to use SMP 865 * APIs will still work using this dummy support. 866 */ 867static void 868mp_setvariables_for_up(void *dummy) 869{ 870 mp_ncpus = 1; 871 mp_ncores = 1; 872 mp_maxid = PCPU_GET(cpuid); 873 CPU_SETOF(mp_maxid, &all_cpus); 874 KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero")); 875} 876SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST, 877 mp_setvariables_for_up, NULL); 878#endif /* SMP */ 879 880void 881smp_no_rendezvous_barrier(void *dummy) 882{ 883#ifdef SMP 884 KASSERT((!smp_started),("smp_no_rendezvous called and smp is started")); 885#endif 886} 887 888void 889smp_rendezvous_cpus_retry(cpuset_t map, 890 void (* setup_func)(void *), 891 void (* action_func)(void *), 892 void (* teardown_func)(void *), 893 void (* wait_func)(void *, int), 894 struct smp_rendezvous_cpus_retry_arg *arg) 895{ 896 int cpu; 897 898 CPU_COPY(&map, &arg->cpus); 899 900 /* 901 * Only one CPU to execute on. 902 */ 903 if (!smp_started) { 904 spinlock_enter(); 905 if (setup_func != NULL) 906 setup_func(arg); 907 if (action_func != NULL) 908 action_func(arg); 909 if (teardown_func != NULL) 910 teardown_func(arg); 911 spinlock_exit(); 912 return; 913 } 914 915 /* 916 * Execute an action on all specified CPUs while retrying until they 917 * all acknowledge completion. 918 */ 919 for (;;) { 920 smp_rendezvous_cpus( 921 arg->cpus, 922 setup_func, 923 action_func, 924 teardown_func, 925 arg); 926 927 if (CPU_EMPTY(&arg->cpus)) 928 break; 929 930 CPU_FOREACH(cpu) { 931 if (!CPU_ISSET(cpu, &arg->cpus)) 932 continue; 933 wait_func(arg, cpu); 934 } 935 } 936} 937 938void 939smp_rendezvous_cpus_done(struct smp_rendezvous_cpus_retry_arg *arg) 940{ 941 942 CPU_CLR_ATOMIC(curcpu, &arg->cpus); 943} 944 945/* 946 * If (prio & PDROP) == 0: 947 * Wait for specified idle threads to switch once. This ensures that even 948 * preempted threads have cycled through the switch function once, 949 * exiting their codepaths. This allows us to change global pointers 950 * with no other synchronization. 951 * If (prio & PDROP) != 0: 952 * Force the specified CPUs to switch context at least once. 953 */ 954int 955quiesce_cpus(cpuset_t map, const char *wmesg, int prio) 956{ 957 struct pcpu *pcpu; 958 u_int *gen; 959 int error; 960 int cpu; 961 962 error = 0; 963 if ((prio & PDROP) == 0) { 964 gen = malloc(sizeof(u_int) * MAXCPU, M_TEMP, M_WAITOK); 965 for (cpu = 0; cpu <= mp_maxid; cpu++) { 966 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 967 continue; 968 pcpu = pcpu_find(cpu); 969 gen[cpu] = pcpu->pc_idlethread->td_generation; 970 } 971 } 972 for (cpu = 0; cpu <= mp_maxid; cpu++) { 973 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 974 continue; 975 pcpu = pcpu_find(cpu); 976 thread_lock(curthread); 977 sched_bind(curthread, cpu); 978 thread_unlock(curthread); 979 if ((prio & PDROP) != 0) 980 continue; 981 while (gen[cpu] == pcpu->pc_idlethread->td_generation) { 982 error = tsleep(quiesce_cpus, prio & ~PDROP, wmesg, 1); 983 if (error != EWOULDBLOCK) 984 goto out; 985 error = 0; 986 } 987 } 988out: 989 thread_lock(curthread); 990 sched_unbind(curthread); 991 thread_unlock(curthread); 992 if ((prio & PDROP) == 0) 993 free(gen, M_TEMP); 994 995 return (error); 996} 997 998int 999quiesce_all_cpus(const char *wmesg, int prio) 1000{ 1001 1002 return quiesce_cpus(all_cpus, wmesg, prio); 1003} 1004 1005/* 1006 * Observe all CPUs not executing in critical section. 1007 * We are not in one so the check for us is safe. If the found 1008 * thread changes to something else we know the section was 1009 * exited as well. 1010 */ 1011void 1012quiesce_all_critical(void) 1013{ 1014 struct thread *td, *newtd; 1015 struct pcpu *pcpu; 1016 int cpu; 1017 1018 MPASS(curthread->td_critnest == 0); 1019 1020 CPU_FOREACH(cpu) { 1021 pcpu = cpuid_to_pcpu[cpu]; 1022 td = pcpu->pc_curthread; 1023 for (;;) { 1024 if (td->td_critnest == 0) 1025 break; 1026 cpu_spinwait(); 1027 newtd = (struct thread *) 1028 atomic_load_acq_ptr((void *)pcpu->pc_curthread); 1029 if (td != newtd) 1030 break; 1031 } 1032 } 1033} 1034 1035static void 1036cpus_fence_seq_cst_issue(void *arg __unused) 1037{ 1038 1039 atomic_thread_fence_seq_cst(); 1040} 1041 1042/* 1043 * Send an IPI forcing a sequentially consistent fence. 1044 * 1045 * Allows replacement of an explicitly fence with a compiler barrier. 1046 * Trades speed up during normal execution for a significant slowdown when 1047 * the barrier is needed. 1048 */ 1049void 1050cpus_fence_seq_cst(void) 1051{ 1052 1053#ifdef SMP 1054 smp_rendezvous( 1055 smp_no_rendezvous_barrier, 1056 cpus_fence_seq_cst_issue, 1057 smp_no_rendezvous_barrier, 1058 NULL 1059 ); 1060#else 1061 cpus_fence_seq_cst_issue(NULL); 1062#endif 1063} 1064 1065/* Extra care is taken with this sysctl because the data type is volatile */ 1066static int 1067sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS) 1068{ 1069 int error, active; 1070 1071 active = smp_started; 1072 error = SYSCTL_OUT(req, &active, sizeof(active)); 1073 return (error); 1074} 1075 1076#ifdef SMP 1077void 1078topo_init_node(struct topo_node *node) 1079{ 1080 1081 bzero(node, sizeof(*node)); 1082 TAILQ_INIT(&node->children); 1083} 1084 1085void 1086topo_init_root(struct topo_node *root) 1087{ 1088 1089 topo_init_node(root); 1090 root->type = TOPO_TYPE_SYSTEM; 1091} 1092 1093/* 1094 * Add a child node with the given ID under the given parent. 1095 * Do nothing if there is already a child with that ID. 1096 */ 1097struct topo_node * 1098topo_add_node_by_hwid(struct topo_node *parent, int hwid, 1099 topo_node_type type, uintptr_t subtype) 1100{ 1101 struct topo_node *node; 1102 1103 TAILQ_FOREACH_REVERSE(node, &parent->children, 1104 topo_children, siblings) { 1105 if (node->hwid == hwid 1106 && node->type == type && node->subtype == subtype) { 1107 return (node); 1108 } 1109 } 1110 1111 node = malloc(sizeof(*node), M_TOPO, M_WAITOK); 1112 topo_init_node(node); 1113 node->parent = parent; 1114 node->hwid = hwid; 1115 node->type = type; 1116 node->subtype = subtype; 1117 TAILQ_INSERT_TAIL(&parent->children, node, siblings); 1118 parent->nchildren++; 1119 1120 return (node); 1121} 1122 1123/* 1124 * Find a child node with the given ID under the given parent. 1125 */ 1126struct topo_node * 1127topo_find_node_by_hwid(struct topo_node *parent, int hwid, 1128 topo_node_type type, uintptr_t subtype) 1129{ 1130 1131 struct topo_node *node; 1132 1133 TAILQ_FOREACH(node, &parent->children, siblings) { 1134 if (node->hwid == hwid 1135 && node->type == type && node->subtype == subtype) { 1136 return (node); 1137 } 1138 } 1139 1140 return (NULL); 1141} 1142 1143/* 1144 * Given a node change the order of its parent's child nodes such 1145 * that the node becomes the firt child while preserving the cyclic 1146 * order of the children. In other words, the given node is promoted 1147 * by rotation. 1148 */ 1149void 1150topo_promote_child(struct topo_node *child) 1151{ 1152 struct topo_node *next; 1153 struct topo_node *node; 1154 struct topo_node *parent; 1155 1156 parent = child->parent; 1157 next = TAILQ_NEXT(child, siblings); 1158 TAILQ_REMOVE(&parent->children, child, siblings); 1159 TAILQ_INSERT_HEAD(&parent->children, child, siblings); 1160 1161 while (next != NULL) { 1162 node = next; 1163 next = TAILQ_NEXT(node, siblings); 1164 TAILQ_REMOVE(&parent->children, node, siblings); 1165 TAILQ_INSERT_AFTER(&parent->children, child, node, siblings); 1166 child = node; 1167 } 1168} 1169 1170/* 1171 * Iterate to the next node in the depth-first search (traversal) of 1172 * the topology tree. 1173 */ 1174struct topo_node * 1175topo_next_node(struct topo_node *top, struct topo_node *node) 1176{ 1177 struct topo_node *next; 1178 1179 if ((next = TAILQ_FIRST(&node->children)) != NULL) 1180 return (next); 1181 1182 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1183 return (next); 1184 1185 while (node != top && (node = node->parent) != top) 1186 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1187 return (next); 1188 1189 return (NULL); 1190} 1191 1192/* 1193 * Iterate to the next node in the depth-first search of the topology tree, 1194 * but without descending below the current node. 1195 */ 1196struct topo_node * 1197topo_next_nonchild_node(struct topo_node *top, struct topo_node *node) 1198{ 1199 struct topo_node *next; 1200 1201 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1202 return (next); 1203 1204 while (node != top && (node = node->parent) != top) 1205 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1206 return (next); 1207 1208 return (NULL); 1209} 1210 1211/* 1212 * Assign the given ID to the given topology node that represents a logical 1213 * processor. 1214 */ 1215void 1216topo_set_pu_id(struct topo_node *node, cpuid_t id) 1217{ 1218 1219 KASSERT(node->type == TOPO_TYPE_PU, 1220 ("topo_set_pu_id: wrong node type: %u", node->type)); 1221 KASSERT(CPU_EMPTY(&node->cpuset) && node->cpu_count == 0, 1222 ("topo_set_pu_id: cpuset already not empty")); 1223 node->id = id; 1224 CPU_SET(id, &node->cpuset); 1225 node->cpu_count = 1; 1226 node->subtype = 1; 1227 1228 while ((node = node->parent) != NULL) { 1229 KASSERT(!CPU_ISSET(id, &node->cpuset), 1230 ("logical ID %u is already set in node %p", id, node)); 1231 CPU_SET(id, &node->cpuset); 1232 node->cpu_count++; 1233 } 1234} 1235 1236static struct topology_spec { 1237 topo_node_type type; 1238 bool match_subtype; 1239 uintptr_t subtype; 1240} topology_level_table[TOPO_LEVEL_COUNT] = { 1241 [TOPO_LEVEL_PKG] = { .type = TOPO_TYPE_PKG, }, 1242 [TOPO_LEVEL_GROUP] = { .type = TOPO_TYPE_GROUP, }, 1243 [TOPO_LEVEL_CACHEGROUP] = { 1244 .type = TOPO_TYPE_CACHE, 1245 .match_subtype = true, 1246 .subtype = CG_SHARE_L3, 1247 }, 1248 [TOPO_LEVEL_CORE] = { .type = TOPO_TYPE_CORE, }, 1249 [TOPO_LEVEL_THREAD] = { .type = TOPO_TYPE_PU, }, 1250}; 1251 1252static bool 1253topo_analyze_table(struct topo_node *root, int all, enum topo_level level, 1254 struct topo_analysis *results) 1255{ 1256 struct topology_spec *spec; 1257 struct topo_node *node; 1258 int count; 1259 1260 if (level >= TOPO_LEVEL_COUNT) 1261 return (true); 1262 1263 spec = &topology_level_table[level]; 1264 count = 0; 1265 node = topo_next_node(root, root); 1266 1267 while (node != NULL) { 1268 if (node->type != spec->type || 1269 (spec->match_subtype && node->subtype != spec->subtype)) { 1270 node = topo_next_node(root, node); 1271 continue; 1272 } 1273 if (!all && CPU_EMPTY(&node->cpuset)) { 1274 node = topo_next_nonchild_node(root, node); 1275 continue; 1276 } 1277 1278 count++; 1279 1280 if (!topo_analyze_table(node, all, level + 1, results)) 1281 return (false); 1282 1283 node = topo_next_nonchild_node(root, node); 1284 } 1285 1286 /* No explicit subgroups is essentially one subgroup. */ 1287 if (count == 0) { 1288 count = 1; 1289 1290 if (!topo_analyze_table(root, all, level + 1, results)) 1291 return (false); 1292 } 1293 1294 if (results->entities[level] == -1) 1295 results->entities[level] = count; 1296 else if (results->entities[level] != count) 1297 return (false); 1298 1299 return (true); 1300} 1301 1302/* 1303 * Check if the topology is uniform, that is, each package has the same number 1304 * of cores in it and each core has the same number of threads (logical 1305 * processors) in it. If so, calculate the number of packages, the number of 1306 * groups per package, the number of cachegroups per group, and the number of 1307 * logical processors per cachegroup. 'all' parameter tells whether to include 1308 * administratively disabled logical processors into the analysis. 1309 */ 1310int 1311topo_analyze(struct topo_node *topo_root, int all, 1312 struct topo_analysis *results) 1313{ 1314 1315 results->entities[TOPO_LEVEL_PKG] = -1; 1316 results->entities[TOPO_LEVEL_CORE] = -1; 1317 results->entities[TOPO_LEVEL_THREAD] = -1; 1318 results->entities[TOPO_LEVEL_GROUP] = -1; 1319 results->entities[TOPO_LEVEL_CACHEGROUP] = -1; 1320 1321 if (!topo_analyze_table(topo_root, all, TOPO_LEVEL_PKG, results)) 1322 return (0); 1323 1324 KASSERT(results->entities[TOPO_LEVEL_PKG] > 0, 1325 ("bug in topology or analysis")); 1326 1327 return (1); 1328} 1329 1330#endif /* SMP */ 1331