1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/kernel.h> 37 #include <sys/ktr.h> 38 #include <sys/proc.h> 39 #include <sys/bus.h> 40 #include <sys/lock.h> 41 #include <sys/malloc.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/pcb.h> 50 #include <machine/smp.h> 51 52 #include "opt_sched.h" 53 54 #ifdef SMP 55 MALLOC_DEFINE(M_TOPO, "toponodes", "SMP topology data"); 56 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 66 static int sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS); 67 68 /* This is used in modules that need to work in both SMP and UP. */ 69 cpuset_t all_cpus; 70 71 int mp_ncpus; 72 /* export this for libkvm consumers. */ 73 int mp_maxcpus = MAXCPU; 74 75 volatile int smp_started; 76 u_int mp_maxid; 77 78 /* Array of CPU contexts saved during a panic. */ 79 struct pcb *stoppcbs; 80 81 static SYSCTL_NODE(_kern, OID_AUTO, smp, 82 CTLFLAG_RD | CTLFLAG_CAPRD | CTLFLAG_MPSAFE, NULL, 83 "Kernel SMP"); 84 85 SYSCTL_INT(_kern_smp, OID_AUTO, maxid, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxid, 0, 86 "Max CPU ID."); 87 88 SYSCTL_INT(_kern_smp, OID_AUTO, maxcpus, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxcpus, 89 0, "Max number of CPUs that the system was compiled for."); 90 91 SYSCTL_PROC(_kern_smp, OID_AUTO, active, CTLFLAG_RD|CTLTYPE_INT|CTLFLAG_MPSAFE, 92 NULL, 0, sysctl_kern_smp_active, "I", 93 "Indicates system is running in SMP mode"); 94 95 int smp_disabled = 0; /* has smp been disabled? */ 96 SYSCTL_INT(_kern_smp, OID_AUTO, disabled, CTLFLAG_RDTUN|CTLFLAG_CAPRD, 97 &smp_disabled, 0, "SMP has been disabled from the loader"); 98 99 int smp_cpus = 1; /* how many cpu's running */ 100 SYSCTL_INT(_kern_smp, OID_AUTO, cpus, CTLFLAG_RD|CTLFLAG_CAPRD, &smp_cpus, 0, 101 "Number of CPUs online"); 102 103 int smp_threads_per_core = 1; /* how many SMT threads are running per core */ 104 SYSCTL_INT(_kern_smp, OID_AUTO, threads_per_core, CTLFLAG_RD|CTLFLAG_CAPRD, 105 &smp_threads_per_core, 0, "Number of SMT threads online per core"); 106 107 int mp_ncores = -1; /* how many physical cores running */ 108 SYSCTL_INT(_kern_smp, OID_AUTO, cores, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_ncores, 0, 109 "Number of physical cores online"); 110 111 int smp_topology = 0; /* Which topology we're using. */ 112 SYSCTL_INT(_kern_smp, OID_AUTO, topology, CTLFLAG_RDTUN, &smp_topology, 0, 113 "Topology override setting; 0 is default provided by hardware."); 114 115 #ifdef SMP 116 /* Variables needed for SMP rendezvous. */ 117 static volatile int smp_rv_ncpus; 118 static void (*volatile smp_rv_setup_func)(void *arg); 119 static void (*volatile smp_rv_action_func)(void *arg); 120 static void (*volatile smp_rv_teardown_func)(void *arg); 121 static void *volatile smp_rv_func_arg; 122 static volatile int smp_rv_waiters[4]; 123 124 /* 125 * Shared mutex to restrict busywaits between smp_rendezvous() and 126 * smp(_targeted)_tlb_shootdown(). A deadlock occurs if both of these 127 * functions trigger at once and cause multiple CPUs to busywait with 128 * interrupts disabled. 129 */ 130 struct mtx smp_ipi_mtx; 131 132 /* 133 * Let the MD SMP code initialize mp_maxid very early if it can. 134 */ 135 static void 136 mp_setmaxid(void *dummy) 137 { 138 139 cpu_mp_setmaxid(); 140 141 KASSERT(mp_ncpus >= 1, ("%s: CPU count < 1", __func__)); 142 KASSERT(mp_ncpus > 1 || mp_maxid == 0, 143 ("%s: one CPU but mp_maxid is not zero", __func__)); 144 KASSERT(mp_maxid >= mp_ncpus - 1, 145 ("%s: counters out of sync: max %d, count %d", __func__, 146 mp_maxid, mp_ncpus)); 147 148 cpusetsizemin = howmany(mp_maxid + 1, NBBY); 149 } 150 SYSINIT(cpu_mp_setmaxid, SI_SUB_TUNABLES, SI_ORDER_FIRST, mp_setmaxid, NULL); 151 152 /* 153 * Call the MD SMP initialization code. 154 */ 155 static void 156 mp_start(void *dummy) 157 { 158 159 mtx_init(&smp_ipi_mtx, "smp rendezvous", NULL, MTX_SPIN); 160 161 /* Probe for MP hardware. */ 162 if (smp_disabled != 0 || cpu_mp_probe() == 0) { 163 mp_ncores = 1; 164 mp_ncpus = 1; 165 CPU_SETOF(PCPU_GET(cpuid), &all_cpus); 166 return; 167 } 168 169 cpu_mp_start(); 170 printf("FreeBSD/SMP: Multiprocessor System Detected: %d CPUs\n", 171 mp_ncpus); 172 173 /* Provide a default for most architectures that don't have SMT/HTT. */ 174 if (mp_ncores < 0) 175 mp_ncores = mp_ncpus; 176 177 stoppcbs = mallocarray(mp_maxid + 1, sizeof(struct pcb), M_DEVBUF, 178 M_WAITOK | M_ZERO); 179 180 cpu_mp_announce(); 181 } 182 SYSINIT(cpu_mp, SI_SUB_CPU, SI_ORDER_THIRD, mp_start, NULL); 183 184 void 185 forward_signal(struct thread *td) 186 { 187 int id; 188 189 /* 190 * signotify() has already set TDA_AST and TDA_SIG on td_ast for 191 * this thread, so all we need to do is poke it if it is currently 192 * executing so that it executes ast(). 193 */ 194 THREAD_LOCK_ASSERT(td, MA_OWNED); 195 KASSERT(TD_IS_RUNNING(td), 196 ("forward_signal: thread is not TDS_RUNNING")); 197 198 CTR1(KTR_SMP, "forward_signal(%p)", td->td_proc); 199 200 if (!smp_started || cold || KERNEL_PANICKED()) 201 return; 202 203 /* No need to IPI ourself. */ 204 if (td == curthread) 205 return; 206 207 id = td->td_oncpu; 208 if (id == NOCPU) 209 return; 210 ipi_cpu(id, IPI_AST); 211 } 212 213 /* 214 * When called the executing CPU will send an IPI to all other CPUs 215 * requesting that they halt execution. 216 * 217 * Usually (but not necessarily) called with 'other_cpus' as its arg. 218 * 219 * - Signals all CPUs in map to stop. 220 * - Waits for each to stop. 221 * 222 * Returns: 223 * -1: error 224 * 0: NA 225 * 1: ok 226 * 227 */ 228 #if defined(__amd64__) || defined(__i386__) 229 #define X86 1 230 #else 231 #define X86 0 232 #endif 233 static int 234 generic_stop_cpus(cpuset_t map, u_int type) 235 { 236 #ifdef KTR 237 char cpusetbuf[CPUSETBUFSIZ]; 238 #endif 239 static volatile u_int stopping_cpu = NOCPU; 240 int i; 241 volatile cpuset_t *cpus; 242 243 KASSERT( 244 type == IPI_STOP || type == IPI_STOP_HARD 245 #if X86 246 || type == IPI_SUSPEND 247 #endif 248 , ("%s: invalid stop type", __func__)); 249 250 if (!smp_started) 251 return (0); 252 253 CTR2(KTR_SMP, "stop_cpus(%s) with %u type", 254 cpusetobj_strprint(cpusetbuf, &map), type); 255 256 #if X86 257 /* 258 * When suspending, ensure there are are no IPIs in progress. 259 * IPIs that have been issued, but not yet delivered (e.g. 260 * not pending on a vCPU when running under virtualization) 261 * will be lost, violating FreeBSD's assumption of reliable 262 * IPI delivery. 263 */ 264 if (type == IPI_SUSPEND) 265 mtx_lock_spin(&smp_ipi_mtx); 266 #endif 267 268 #if X86 269 if (!nmi_is_broadcast || nmi_kdb_lock == 0) { 270 #endif 271 if (stopping_cpu != PCPU_GET(cpuid)) 272 while (atomic_cmpset_int(&stopping_cpu, NOCPU, 273 PCPU_GET(cpuid)) == 0) 274 while (stopping_cpu != NOCPU) 275 cpu_spinwait(); /* spin */ 276 277 /* send the stop IPI to all CPUs in map */ 278 ipi_selected(map, type); 279 #if X86 280 } 281 #endif 282 283 #if X86 284 if (type == IPI_SUSPEND) 285 cpus = &suspended_cpus; 286 else 287 #endif 288 cpus = &stopped_cpus; 289 290 i = 0; 291 while (!CPU_SUBSET(cpus, &map)) { 292 /* spin */ 293 cpu_spinwait(); 294 i++; 295 if (i == 100000000) { 296 printf("timeout stopping cpus\n"); 297 break; 298 } 299 } 300 301 #if X86 302 if (type == IPI_SUSPEND) 303 mtx_unlock_spin(&smp_ipi_mtx); 304 #endif 305 306 stopping_cpu = NOCPU; 307 return (1); 308 } 309 310 int 311 stop_cpus(cpuset_t map) 312 { 313 314 return (generic_stop_cpus(map, IPI_STOP)); 315 } 316 317 int 318 stop_cpus_hard(cpuset_t map) 319 { 320 321 return (generic_stop_cpus(map, IPI_STOP_HARD)); 322 } 323 324 #if X86 325 int 326 suspend_cpus(cpuset_t map) 327 { 328 329 return (generic_stop_cpus(map, IPI_SUSPEND)); 330 } 331 #endif 332 333 /* 334 * Called by a CPU to restart stopped CPUs. 335 * 336 * Usually (but not necessarily) called with 'stopped_cpus' as its arg. 337 * 338 * - Signals all CPUs in map to restart. 339 * - Waits for each to restart. 340 * 341 * Returns: 342 * -1: error 343 * 0: NA 344 * 1: ok 345 */ 346 static int 347 generic_restart_cpus(cpuset_t map, u_int type) 348 { 349 #ifdef KTR 350 char cpusetbuf[CPUSETBUFSIZ]; 351 #endif 352 volatile cpuset_t *cpus; 353 354 #if X86 355 KASSERT(type == IPI_STOP || type == IPI_STOP_HARD 356 || type == IPI_SUSPEND, ("%s: invalid stop type", __func__)); 357 358 if (!smp_started) 359 return (0); 360 361 CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); 362 363 if (type == IPI_SUSPEND) 364 cpus = &resuming_cpus; 365 else 366 cpus = &stopped_cpus; 367 368 /* signal other cpus to restart */ 369 if (type == IPI_SUSPEND) 370 CPU_COPY_STORE_REL(&map, &toresume_cpus); 371 else 372 CPU_COPY_STORE_REL(&map, &started_cpus); 373 374 /* 375 * Wake up any CPUs stopped with MWAIT. From MI code we can't tell if 376 * MONITOR/MWAIT is enabled, but the potentially redundant writes are 377 * relatively inexpensive. 378 */ 379 if (type == IPI_STOP) { 380 struct monitorbuf *mb; 381 u_int id; 382 383 CPU_FOREACH(id) { 384 if (!CPU_ISSET(id, &map)) 385 continue; 386 387 mb = &pcpu_find(id)->pc_monitorbuf; 388 atomic_store_int(&mb->stop_state, 389 MONITOR_STOPSTATE_RUNNING); 390 } 391 } 392 393 if (!nmi_is_broadcast || nmi_kdb_lock == 0) { 394 /* wait for each to clear its bit */ 395 while (CPU_OVERLAP(cpus, &map)) 396 cpu_spinwait(); 397 } 398 #else /* !X86 */ 399 KASSERT(type == IPI_STOP || type == IPI_STOP_HARD, 400 ("%s: invalid stop type", __func__)); 401 402 if (!smp_started) 403 return (0); 404 405 CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); 406 407 cpus = &stopped_cpus; 408 409 /* signal other cpus to restart */ 410 CPU_COPY_STORE_REL(&map, &started_cpus); 411 412 /* wait for each to clear its bit */ 413 while (CPU_OVERLAP(cpus, &map)) 414 cpu_spinwait(); 415 #endif 416 return (1); 417 } 418 419 int 420 restart_cpus(cpuset_t map) 421 { 422 423 return (generic_restart_cpus(map, IPI_STOP)); 424 } 425 426 #if X86 427 int 428 resume_cpus(cpuset_t map) 429 { 430 431 return (generic_restart_cpus(map, IPI_SUSPEND)); 432 } 433 #endif 434 #undef X86 435 436 /* 437 * All-CPU rendezvous. CPUs are signalled, all execute the setup function 438 * (if specified), rendezvous, execute the action function (if specified), 439 * rendezvous again, execute the teardown function (if specified), and then 440 * resume. 441 * 442 * Note that the supplied external functions _must_ be reentrant and aware 443 * that they are running in parallel and in an unknown lock context. 444 */ 445 void 446 smp_rendezvous_action(void) 447 { 448 struct thread *td; 449 void *local_func_arg; 450 void (*local_setup_func)(void*); 451 void (*local_action_func)(void*); 452 void (*local_teardown_func)(void*); 453 #ifdef INVARIANTS 454 int owepreempt; 455 #endif 456 457 /* Ensure we have up-to-date values. */ 458 atomic_add_acq_int(&smp_rv_waiters[0], 1); 459 while (smp_rv_waiters[0] < smp_rv_ncpus) 460 cpu_spinwait(); 461 462 /* Fetch rendezvous parameters after acquire barrier. */ 463 local_func_arg = smp_rv_func_arg; 464 local_setup_func = smp_rv_setup_func; 465 local_action_func = smp_rv_action_func; 466 local_teardown_func = smp_rv_teardown_func; 467 468 /* 469 * Use a nested critical section to prevent any preemptions 470 * from occurring during a rendezvous action routine. 471 * Specifically, if a rendezvous handler is invoked via an IPI 472 * and the interrupted thread was in the critical_exit() 473 * function after setting td_critnest to 0 but before 474 * performing a deferred preemption, this routine can be 475 * invoked with td_critnest set to 0 and td_owepreempt true. 476 * In that case, a critical_exit() during the rendezvous 477 * action would trigger a preemption which is not permitted in 478 * a rendezvous action. To fix this, wrap all of the 479 * rendezvous action handlers in a critical section. We 480 * cannot use a regular critical section however as having 481 * critical_exit() preempt from this routine would also be 482 * problematic (the preemption must not occur before the IPI 483 * has been acknowledged via an EOI). Instead, we 484 * intentionally ignore td_owepreempt when leaving the 485 * critical section. This should be harmless because we do 486 * not permit rendezvous action routines to schedule threads, 487 * and thus td_owepreempt should never transition from 0 to 1 488 * during this routine. 489 */ 490 td = curthread; 491 td->td_critnest++; 492 #ifdef INVARIANTS 493 owepreempt = td->td_owepreempt; 494 #endif 495 496 /* 497 * If requested, run a setup function before the main action 498 * function. Ensure all CPUs have completed the setup 499 * function before moving on to the action function. 500 */ 501 if (local_setup_func != smp_no_rendezvous_barrier) { 502 if (local_setup_func != NULL) 503 local_setup_func(local_func_arg); 504 atomic_add_int(&smp_rv_waiters[1], 1); 505 while (smp_rv_waiters[1] < smp_rv_ncpus) 506 cpu_spinwait(); 507 } 508 509 if (local_action_func != NULL) 510 local_action_func(local_func_arg); 511 512 if (local_teardown_func != smp_no_rendezvous_barrier) { 513 /* 514 * Signal that the main action has been completed. If a 515 * full exit rendezvous is requested, then all CPUs will 516 * wait here until all CPUs have finished the main action. 517 */ 518 atomic_add_int(&smp_rv_waiters[2], 1); 519 while (smp_rv_waiters[2] < smp_rv_ncpus) 520 cpu_spinwait(); 521 522 if (local_teardown_func != NULL) 523 local_teardown_func(local_func_arg); 524 } 525 526 /* 527 * Signal that the rendezvous is fully completed by this CPU. 528 * This means that no member of smp_rv_* pseudo-structure will be 529 * accessed by this target CPU after this point; in particular, 530 * memory pointed by smp_rv_func_arg. 531 * 532 * The release semantic ensures that all accesses performed by 533 * the current CPU are visible when smp_rendezvous_cpus() 534 * returns, by synchronizing with the 535 * atomic_load_acq_int(&smp_rv_waiters[3]). 536 */ 537 atomic_add_rel_int(&smp_rv_waiters[3], 1); 538 539 td->td_critnest--; 540 KASSERT(owepreempt == td->td_owepreempt, 541 ("rendezvous action changed td_owepreempt")); 542 } 543 544 void 545 smp_rendezvous_cpus(cpuset_t map, 546 void (* setup_func)(void *), 547 void (* action_func)(void *), 548 void (* teardown_func)(void *), 549 void *arg) 550 { 551 int curcpumap, i, ncpus = 0; 552 553 /* See comments in the !SMP case. */ 554 if (!smp_started) { 555 spinlock_enter(); 556 if (setup_func != NULL) 557 setup_func(arg); 558 if (action_func != NULL) 559 action_func(arg); 560 if (teardown_func != NULL) 561 teardown_func(arg); 562 spinlock_exit(); 563 return; 564 } 565 566 /* 567 * Make sure we come here with interrupts enabled. Otherwise we 568 * livelock if smp_ipi_mtx is owned by a thread which sent us an IPI. 569 */ 570 MPASS(curthread->td_md.md_spinlock_count == 0); 571 572 CPU_FOREACH(i) { 573 if (CPU_ISSET(i, &map)) 574 ncpus++; 575 } 576 if (ncpus == 0) 577 panic("ncpus is 0 with non-zero map"); 578 579 mtx_lock_spin(&smp_ipi_mtx); 580 581 /* Pass rendezvous parameters via global variables. */ 582 smp_rv_ncpus = ncpus; 583 smp_rv_setup_func = setup_func; 584 smp_rv_action_func = action_func; 585 smp_rv_teardown_func = teardown_func; 586 smp_rv_func_arg = arg; 587 smp_rv_waiters[1] = 0; 588 smp_rv_waiters[2] = 0; 589 smp_rv_waiters[3] = 0; 590 atomic_store_rel_int(&smp_rv_waiters[0], 0); 591 592 /* 593 * Signal other processors, which will enter the IPI with 594 * interrupts off. 595 */ 596 curcpumap = CPU_ISSET(curcpu, &map); 597 CPU_CLR(curcpu, &map); 598 ipi_selected(map, IPI_RENDEZVOUS); 599 600 /* Check if the current CPU is in the map */ 601 if (curcpumap != 0) 602 smp_rendezvous_action(); 603 604 /* 605 * Ensure that the master CPU waits for all the other 606 * CPUs to finish the rendezvous, so that smp_rv_* 607 * pseudo-structure and the arg are guaranteed to not 608 * be in use. 609 * 610 * Load acquire synchronizes with the release add in 611 * smp_rendezvous_action(), which ensures that our caller sees 612 * all memory actions done by the called functions on other 613 * CPUs. 614 */ 615 while (atomic_load_acq_int(&smp_rv_waiters[3]) < ncpus) 616 cpu_spinwait(); 617 618 mtx_unlock_spin(&smp_ipi_mtx); 619 } 620 621 void 622 smp_rendezvous(void (* setup_func)(void *), 623 void (* action_func)(void *), 624 void (* teardown_func)(void *), 625 void *arg) 626 { 627 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); 628 } 629 630 static void 631 smp_topo_fill(struct cpu_group *cg) 632 { 633 int c; 634 635 for (c = 0; c < cg->cg_children; c++) 636 smp_topo_fill(&cg->cg_child[c]); 637 cg->cg_first = CPU_FFS(&cg->cg_mask) - 1; 638 cg->cg_last = CPU_FLS(&cg->cg_mask) - 1; 639 } 640 641 struct cpu_group * 642 smp_topo(void) 643 { 644 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 645 static struct cpu_group *top = NULL; 646 647 /* 648 * The first call to smp_topo() is guaranteed to occur 649 * during the kernel boot while we are still single-threaded. 650 */ 651 if (top != NULL) 652 return (top); 653 654 /* 655 * Check for a fake topology request for debugging purposes. 656 */ 657 switch (smp_topology) { 658 case 1: 659 /* Dual core with no sharing. */ 660 top = smp_topo_1level(CG_SHARE_NONE, 2, 0); 661 break; 662 case 2: 663 /* No topology, all cpus are equal. */ 664 top = smp_topo_none(); 665 break; 666 case 3: 667 /* Dual core with shared L2. */ 668 top = smp_topo_1level(CG_SHARE_L2, 2, 0); 669 break; 670 case 4: 671 /* quad core, shared l3 among each package, private l2. */ 672 top = smp_topo_1level(CG_SHARE_L3, 4, 0); 673 break; 674 case 5: 675 /* quad core, 2 dualcore parts on each package share l2. */ 676 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); 677 break; 678 case 6: 679 /* Single-core 2xHTT */ 680 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); 681 break; 682 case 7: 683 /* quad core with a shared l3, 8 threads sharing L2. */ 684 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, 685 CG_FLAG_SMT); 686 break; 687 default: 688 /* Default, ask the system what it wants. */ 689 top = cpu_topo(); 690 break; 691 } 692 /* 693 * Verify the returned topology. 694 */ 695 if (top->cg_count != mp_ncpus) 696 panic("Built bad topology at %p. CPU count %d != %d", 697 top, top->cg_count, mp_ncpus); 698 if (CPU_CMP(&top->cg_mask, &all_cpus)) 699 panic("Built bad topology at %p. CPU mask (%s) != (%s)", 700 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), 701 cpusetobj_strprint(cpusetbuf2, &all_cpus)); 702 703 /* 704 * Collapse nonsense levels that may be created out of convenience by 705 * the MD layers. They cause extra work in the search functions. 706 */ 707 while (top->cg_children == 1) { 708 top = &top->cg_child[0]; 709 top->cg_parent = NULL; 710 } 711 smp_topo_fill(top); 712 return (top); 713 } 714 715 struct cpu_group * 716 smp_topo_alloc(u_int count) 717 { 718 static struct cpu_group *group = NULL; 719 static u_int index; 720 u_int curr; 721 722 if (group == NULL) { 723 group = mallocarray((mp_maxid + 1) * MAX_CACHE_LEVELS + 1, 724 sizeof(*group), M_DEVBUF, M_WAITOK | M_ZERO); 725 } 726 curr = index; 727 index += count; 728 return (&group[curr]); 729 } 730 731 struct cpu_group * 732 smp_topo_none(void) 733 { 734 struct cpu_group *top; 735 736 top = smp_topo_alloc(1); 737 top->cg_parent = NULL; 738 top->cg_child = NULL; 739 top->cg_mask = all_cpus; 740 top->cg_count = mp_ncpus; 741 top->cg_children = 0; 742 top->cg_level = CG_SHARE_NONE; 743 top->cg_flags = 0; 744 745 return (top); 746 } 747 748 static int 749 smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, 750 int count, int flags, int start) 751 { 752 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 753 cpuset_t mask; 754 int i; 755 756 CPU_ZERO(&mask); 757 for (i = 0; i < count; i++, start++) 758 CPU_SET(start, &mask); 759 child->cg_parent = parent; 760 child->cg_child = NULL; 761 child->cg_children = 0; 762 child->cg_level = share; 763 child->cg_count = count; 764 child->cg_flags = flags; 765 child->cg_mask = mask; 766 parent->cg_children++; 767 for (; parent != NULL; parent = parent->cg_parent) { 768 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) 769 panic("Duplicate children in %p. mask (%s) child (%s)", 770 parent, 771 cpusetobj_strprint(cpusetbuf, &parent->cg_mask), 772 cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); 773 CPU_OR(&parent->cg_mask, &parent->cg_mask, &child->cg_mask); 774 parent->cg_count += child->cg_count; 775 } 776 777 return (start); 778 } 779 780 struct cpu_group * 781 smp_topo_1level(int share, int count, int flags) 782 { 783 struct cpu_group *child; 784 struct cpu_group *top; 785 int packages; 786 int cpu; 787 int i; 788 789 cpu = 0; 790 packages = mp_ncpus / count; 791 top = smp_topo_alloc(1 + packages); 792 top->cg_child = child = top + 1; 793 top->cg_level = CG_SHARE_NONE; 794 for (i = 0; i < packages; i++, child++) 795 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); 796 return (top); 797 } 798 799 struct cpu_group * 800 smp_topo_2level(int l2share, int l2count, int l1share, int l1count, 801 int l1flags) 802 { 803 struct cpu_group *top; 804 struct cpu_group *l1g; 805 struct cpu_group *l2g; 806 int cpu; 807 int i; 808 int j; 809 810 cpu = 0; 811 top = smp_topo_alloc(1 + mp_ncpus / (l2count * l1count) + 812 mp_ncpus / l1count); 813 l2g = top + 1; 814 top->cg_child = l2g; 815 top->cg_level = CG_SHARE_NONE; 816 top->cg_children = mp_ncpus / (l2count * l1count); 817 l1g = l2g + top->cg_children; 818 for (i = 0; i < top->cg_children; i++, l2g++) { 819 l2g->cg_parent = top; 820 l2g->cg_child = l1g; 821 l2g->cg_level = l2share; 822 for (j = 0; j < l2count; j++, l1g++) 823 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, 824 l1flags, cpu); 825 } 826 return (top); 827 } 828 829 struct cpu_group * 830 smp_topo_find(struct cpu_group *top, int cpu) 831 { 832 struct cpu_group *cg; 833 cpuset_t mask; 834 int children; 835 int i; 836 837 CPU_SETOF(cpu, &mask); 838 cg = top; 839 for (;;) { 840 if (!CPU_OVERLAP(&cg->cg_mask, &mask)) 841 return (NULL); 842 if (cg->cg_children == 0) 843 return (cg); 844 children = cg->cg_children; 845 for (i = 0, cg = cg->cg_child; i < children; cg++, i++) 846 if (CPU_OVERLAP(&cg->cg_mask, &mask)) 847 break; 848 } 849 return (NULL); 850 } 851 #else /* !SMP */ 852 853 void 854 smp_rendezvous_cpus(cpuset_t map, 855 void (*setup_func)(void *), 856 void (*action_func)(void *), 857 void (*teardown_func)(void *), 858 void *arg) 859 { 860 /* 861 * In the !SMP case we just need to ensure the same initial conditions 862 * as the SMP case. 863 */ 864 spinlock_enter(); 865 if (setup_func != NULL) 866 setup_func(arg); 867 if (action_func != NULL) 868 action_func(arg); 869 if (teardown_func != NULL) 870 teardown_func(arg); 871 spinlock_exit(); 872 } 873 874 void 875 smp_rendezvous(void (*setup_func)(void *), 876 void (*action_func)(void *), 877 void (*teardown_func)(void *), 878 void *arg) 879 { 880 881 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, 882 arg); 883 } 884 885 /* 886 * Provide dummy SMP support for UP kernels. Modules that need to use SMP 887 * APIs will still work using this dummy support. 888 */ 889 static void 890 mp_setvariables_for_up(void *dummy) 891 { 892 mp_ncpus = 1; 893 mp_ncores = 1; 894 mp_maxid = PCPU_GET(cpuid); 895 CPU_SETOF(mp_maxid, &all_cpus); 896 KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero")); 897 } 898 SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST, 899 mp_setvariables_for_up, NULL); 900 #endif /* SMP */ 901 902 void 903 smp_no_rendezvous_barrier(void *dummy) 904 { 905 #ifdef SMP 906 KASSERT((!smp_started),("smp_no_rendezvous called and smp is started")); 907 #endif 908 } 909 910 void 911 smp_rendezvous_cpus_retry(cpuset_t map, 912 void (* setup_func)(void *), 913 void (* action_func)(void *), 914 void (* teardown_func)(void *), 915 void (* wait_func)(void *, int), 916 struct smp_rendezvous_cpus_retry_arg *arg) 917 { 918 int cpu; 919 920 CPU_COPY(&map, &arg->cpus); 921 922 /* 923 * Only one CPU to execute on. 924 */ 925 if (!smp_started) { 926 spinlock_enter(); 927 if (setup_func != NULL) 928 setup_func(arg); 929 if (action_func != NULL) 930 action_func(arg); 931 if (teardown_func != NULL) 932 teardown_func(arg); 933 spinlock_exit(); 934 return; 935 } 936 937 /* 938 * Execute an action on all specified CPUs while retrying until they 939 * all acknowledge completion. 940 */ 941 for (;;) { 942 smp_rendezvous_cpus( 943 arg->cpus, 944 setup_func, 945 action_func, 946 teardown_func, 947 arg); 948 949 if (CPU_EMPTY(&arg->cpus)) 950 break; 951 952 CPU_FOREACH(cpu) { 953 if (!CPU_ISSET(cpu, &arg->cpus)) 954 continue; 955 wait_func(arg, cpu); 956 } 957 } 958 } 959 960 void 961 smp_rendezvous_cpus_done(struct smp_rendezvous_cpus_retry_arg *arg) 962 { 963 964 CPU_CLR_ATOMIC(curcpu, &arg->cpus); 965 } 966 967 /* 968 * If (prio & PDROP) == 0: 969 * Wait for specified idle threads to switch once. This ensures that even 970 * preempted threads have cycled through the switch function once, 971 * exiting their codepaths. This allows us to change global pointers 972 * with no other synchronization. 973 * If (prio & PDROP) != 0: 974 * Force the specified CPUs to switch context at least once. 975 */ 976 int 977 quiesce_cpus(cpuset_t map, const char *wmesg, int prio) 978 { 979 struct pcpu *pcpu; 980 u_int *gen; 981 int error; 982 int cpu; 983 984 error = 0; 985 if ((prio & PDROP) == 0) { 986 gen = mallocarray(sizeof(u_int), mp_maxid + 1, M_TEMP, 987 M_WAITOK); 988 for (cpu = 0; cpu <= mp_maxid; cpu++) { 989 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 990 continue; 991 pcpu = pcpu_find(cpu); 992 gen[cpu] = pcpu->pc_idlethread->td_generation; 993 } 994 } 995 for (cpu = 0; cpu <= mp_maxid; cpu++) { 996 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 997 continue; 998 pcpu = pcpu_find(cpu); 999 thread_lock(curthread); 1000 sched_bind(curthread, cpu); 1001 thread_unlock(curthread); 1002 if ((prio & PDROP) != 0) 1003 continue; 1004 while (gen[cpu] == pcpu->pc_idlethread->td_generation) { 1005 error = tsleep(quiesce_cpus, prio & ~PDROP, wmesg, 1); 1006 if (error != EWOULDBLOCK) 1007 goto out; 1008 error = 0; 1009 } 1010 } 1011 out: 1012 thread_lock(curthread); 1013 sched_unbind(curthread); 1014 thread_unlock(curthread); 1015 if ((prio & PDROP) == 0) 1016 free(gen, M_TEMP); 1017 1018 return (error); 1019 } 1020 1021 int 1022 quiesce_all_cpus(const char *wmesg, int prio) 1023 { 1024 1025 return quiesce_cpus(all_cpus, wmesg, prio); 1026 } 1027 1028 /* 1029 * Observe all CPUs not executing in critical section. 1030 * We are not in one so the check for us is safe. If the found 1031 * thread changes to something else we know the section was 1032 * exited as well. 1033 */ 1034 void 1035 quiesce_all_critical(void) 1036 { 1037 struct thread *td, *newtd; 1038 struct pcpu *pcpu; 1039 int cpu; 1040 1041 MPASS(curthread->td_critnest == 0); 1042 1043 CPU_FOREACH(cpu) { 1044 pcpu = cpuid_to_pcpu[cpu]; 1045 td = pcpu->pc_curthread; 1046 for (;;) { 1047 if (td->td_critnest == 0) 1048 break; 1049 cpu_spinwait(); 1050 newtd = (struct thread *) 1051 atomic_load_acq_ptr((void *)pcpu->pc_curthread); 1052 if (td != newtd) 1053 break; 1054 } 1055 } 1056 } 1057 1058 static void 1059 cpus_fence_seq_cst_issue(void *arg __unused) 1060 { 1061 1062 atomic_thread_fence_seq_cst(); 1063 } 1064 1065 /* 1066 * Send an IPI forcing a sequentially consistent fence. 1067 * 1068 * Allows replacement of an explicitly fence with a compiler barrier. 1069 * Trades speed up during normal execution for a significant slowdown when 1070 * the barrier is needed. 1071 */ 1072 void 1073 cpus_fence_seq_cst(void) 1074 { 1075 1076 #ifdef SMP 1077 smp_rendezvous( 1078 smp_no_rendezvous_barrier, 1079 cpus_fence_seq_cst_issue, 1080 smp_no_rendezvous_barrier, 1081 NULL 1082 ); 1083 #else 1084 cpus_fence_seq_cst_issue(NULL); 1085 #endif 1086 } 1087 1088 /* Extra care is taken with this sysctl because the data type is volatile */ 1089 static int 1090 sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS) 1091 { 1092 int error, active; 1093 1094 active = smp_started; 1095 error = SYSCTL_OUT(req, &active, sizeof(active)); 1096 return (error); 1097 } 1098 1099 #ifdef SMP 1100 void 1101 topo_init_node(struct topo_node *node) 1102 { 1103 1104 bzero(node, sizeof(*node)); 1105 TAILQ_INIT(&node->children); 1106 } 1107 1108 void 1109 topo_init_root(struct topo_node *root) 1110 { 1111 1112 topo_init_node(root); 1113 root->type = TOPO_TYPE_SYSTEM; 1114 } 1115 1116 /* 1117 * Add a child node with the given ID under the given parent. 1118 * Do nothing if there is already a child with that ID. 1119 */ 1120 struct topo_node * 1121 topo_add_node_by_hwid(struct topo_node *parent, int hwid, 1122 topo_node_type type, uintptr_t subtype) 1123 { 1124 struct topo_node *node; 1125 1126 TAILQ_FOREACH_REVERSE(node, &parent->children, 1127 topo_children, siblings) { 1128 if (node->hwid == hwid 1129 && node->type == type && node->subtype == subtype) { 1130 return (node); 1131 } 1132 } 1133 1134 node = malloc(sizeof(*node), M_TOPO, M_WAITOK); 1135 topo_init_node(node); 1136 node->parent = parent; 1137 node->hwid = hwid; 1138 node->type = type; 1139 node->subtype = subtype; 1140 TAILQ_INSERT_TAIL(&parent->children, node, siblings); 1141 parent->nchildren++; 1142 1143 return (node); 1144 } 1145 1146 /* 1147 * Find a child node with the given ID under the given parent. 1148 */ 1149 struct topo_node * 1150 topo_find_node_by_hwid(struct topo_node *parent, int hwid, 1151 topo_node_type type, uintptr_t subtype) 1152 { 1153 1154 struct topo_node *node; 1155 1156 TAILQ_FOREACH(node, &parent->children, siblings) { 1157 if (node->hwid == hwid 1158 && node->type == type && node->subtype == subtype) { 1159 return (node); 1160 } 1161 } 1162 1163 return (NULL); 1164 } 1165 1166 /* 1167 * Given a node change the order of its parent's child nodes such 1168 * that the node becomes the firt child while preserving the cyclic 1169 * order of the children. In other words, the given node is promoted 1170 * by rotation. 1171 */ 1172 void 1173 topo_promote_child(struct topo_node *child) 1174 { 1175 struct topo_node *next; 1176 struct topo_node *node; 1177 struct topo_node *parent; 1178 1179 parent = child->parent; 1180 next = TAILQ_NEXT(child, siblings); 1181 TAILQ_REMOVE(&parent->children, child, siblings); 1182 TAILQ_INSERT_HEAD(&parent->children, child, siblings); 1183 1184 while (next != NULL) { 1185 node = next; 1186 next = TAILQ_NEXT(node, siblings); 1187 TAILQ_REMOVE(&parent->children, node, siblings); 1188 TAILQ_INSERT_AFTER(&parent->children, child, node, siblings); 1189 child = node; 1190 } 1191 } 1192 1193 /* 1194 * Iterate to the next node in the depth-first search (traversal) of 1195 * the topology tree. 1196 */ 1197 struct topo_node * 1198 topo_next_node(struct topo_node *top, struct topo_node *node) 1199 { 1200 struct topo_node *next; 1201 1202 if ((next = TAILQ_FIRST(&node->children)) != NULL) 1203 return (next); 1204 1205 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1206 return (next); 1207 1208 while (node != top && (node = node->parent) != top) 1209 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1210 return (next); 1211 1212 return (NULL); 1213 } 1214 1215 /* 1216 * Iterate to the next node in the depth-first search of the topology tree, 1217 * but without descending below the current node. 1218 */ 1219 struct topo_node * 1220 topo_next_nonchild_node(struct topo_node *top, struct topo_node *node) 1221 { 1222 struct topo_node *next; 1223 1224 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1225 return (next); 1226 1227 while (node != top && (node = node->parent) != top) 1228 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1229 return (next); 1230 1231 return (NULL); 1232 } 1233 1234 /* 1235 * Assign the given ID to the given topology node that represents a logical 1236 * processor. 1237 */ 1238 void 1239 topo_set_pu_id(struct topo_node *node, cpuid_t id) 1240 { 1241 1242 KASSERT(node->type == TOPO_TYPE_PU, 1243 ("topo_set_pu_id: wrong node type: %u", node->type)); 1244 KASSERT(CPU_EMPTY(&node->cpuset) && node->cpu_count == 0, 1245 ("topo_set_pu_id: cpuset already not empty")); 1246 node->id = id; 1247 CPU_SET(id, &node->cpuset); 1248 node->cpu_count = 1; 1249 node->subtype = 1; 1250 1251 while ((node = node->parent) != NULL) { 1252 KASSERT(!CPU_ISSET(id, &node->cpuset), 1253 ("logical ID %u is already set in node %p", id, node)); 1254 CPU_SET(id, &node->cpuset); 1255 node->cpu_count++; 1256 } 1257 } 1258 1259 static struct topology_spec { 1260 topo_node_type type; 1261 bool match_subtype; 1262 uintptr_t subtype; 1263 } topology_level_table[TOPO_LEVEL_COUNT] = { 1264 [TOPO_LEVEL_PKG] = { .type = TOPO_TYPE_PKG, }, 1265 [TOPO_LEVEL_GROUP] = { .type = TOPO_TYPE_GROUP, }, 1266 [TOPO_LEVEL_CACHEGROUP] = { 1267 .type = TOPO_TYPE_CACHE, 1268 .match_subtype = true, 1269 .subtype = CG_SHARE_L3, 1270 }, 1271 [TOPO_LEVEL_CORE] = { .type = TOPO_TYPE_CORE, }, 1272 [TOPO_LEVEL_THREAD] = { .type = TOPO_TYPE_PU, }, 1273 }; 1274 1275 static bool 1276 topo_analyze_table(struct topo_node *root, int all, enum topo_level level, 1277 struct topo_analysis *results) 1278 { 1279 struct topology_spec *spec; 1280 struct topo_node *node; 1281 int count; 1282 1283 if (level >= TOPO_LEVEL_COUNT) 1284 return (true); 1285 1286 spec = &topology_level_table[level]; 1287 count = 0; 1288 node = topo_next_node(root, root); 1289 1290 while (node != NULL) { 1291 if (node->type != spec->type || 1292 (spec->match_subtype && node->subtype != spec->subtype)) { 1293 node = topo_next_node(root, node); 1294 continue; 1295 } 1296 if (!all && CPU_EMPTY(&node->cpuset)) { 1297 node = topo_next_nonchild_node(root, node); 1298 continue; 1299 } 1300 1301 count++; 1302 1303 if (!topo_analyze_table(node, all, level + 1, results)) 1304 return (false); 1305 1306 node = topo_next_nonchild_node(root, node); 1307 } 1308 1309 /* No explicit subgroups is essentially one subgroup. */ 1310 if (count == 0) { 1311 count = 1; 1312 1313 if (!topo_analyze_table(root, all, level + 1, results)) 1314 return (false); 1315 } 1316 1317 if (results->entities[level] == -1) 1318 results->entities[level] = count; 1319 else if (results->entities[level] != count) 1320 return (false); 1321 1322 return (true); 1323 } 1324 1325 /* 1326 * Check if the topology is uniform, that is, each package has the same number 1327 * of cores in it and each core has the same number of threads (logical 1328 * processors) in it. If so, calculate the number of packages, the number of 1329 * groups per package, the number of cachegroups per group, and the number of 1330 * logical processors per cachegroup. 'all' parameter tells whether to include 1331 * administratively disabled logical processors into the analysis. 1332 */ 1333 int 1334 topo_analyze(struct topo_node *topo_root, int all, 1335 struct topo_analysis *results) 1336 { 1337 1338 results->entities[TOPO_LEVEL_PKG] = -1; 1339 results->entities[TOPO_LEVEL_CORE] = -1; 1340 results->entities[TOPO_LEVEL_THREAD] = -1; 1341 results->entities[TOPO_LEVEL_GROUP] = -1; 1342 results->entities[TOPO_LEVEL_CACHEGROUP] = -1; 1343 1344 if (!topo_analyze_table(topo_root, all, TOPO_LEVEL_PKG, results)) 1345 return (0); 1346 1347 KASSERT(results->entities[TOPO_LEVEL_PKG] > 0, 1348 ("bug in topology or analysis")); 1349 1350 return (1); 1351 } 1352 1353 #endif /* SMP */ 1354