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 56 MALLOC_DEFINE(M_TOPO, "toponodes", "SMP topology data"); 57 58 volatile cpuset_t stopped_cpus; 59 volatile cpuset_t started_cpus; 60 volatile cpuset_t suspended_cpus; 61 cpuset_t hlt_cpus_mask; 62 cpuset_t logical_cpus_mask; 63 64 void (*cpustop_restartfunc)(void); 65 #endif 66 67 static int sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS); 68 69 /* This is used in modules that need to work in both SMP and UP. */ 70 cpuset_t all_cpus; 71 72 int mp_ncpus; 73 /* export this for libkvm consumers. */ 74 int mp_maxcpus = MAXCPU; 75 76 volatile int smp_started; 77 u_int mp_maxid; 78 79 static SYSCTL_NODE(_kern, OID_AUTO, smp, CTLFLAG_RD|CTLFLAG_CAPRD, NULL, 80 "Kernel SMP"); 81 82 SYSCTL_INT(_kern_smp, OID_AUTO, maxid, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxid, 0, 83 "Max CPU ID."); 84 85 SYSCTL_INT(_kern_smp, OID_AUTO, maxcpus, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxcpus, 86 0, "Max number of CPUs that the system was compiled for."); 87 88 SYSCTL_PROC(_kern_smp, OID_AUTO, active, CTLFLAG_RD|CTLTYPE_INT|CTLFLAG_MPSAFE, 89 NULL, 0, sysctl_kern_smp_active, "I", 90 "Indicates system is running in SMP mode"); 91 92 int smp_disabled = 0; /* has smp been disabled? */ 93 SYSCTL_INT(_kern_smp, OID_AUTO, disabled, CTLFLAG_RDTUN|CTLFLAG_CAPRD, 94 &smp_disabled, 0, "SMP has been disabled from the loader"); 95 96 int smp_cpus = 1; /* how many cpu's running */ 97 SYSCTL_INT(_kern_smp, OID_AUTO, cpus, CTLFLAG_RD|CTLFLAG_CAPRD, &smp_cpus, 0, 98 "Number of CPUs online"); 99 100 int smp_threads_per_core = 1; /* how many SMT threads are running per core */ 101 SYSCTL_INT(_kern_smp, OID_AUTO, threads_per_core, CTLFLAG_RD|CTLFLAG_CAPRD, 102 &smp_threads_per_core, 0, "Number of SMT threads online per core"); 103 104 int mp_ncores = -1; /* how many physical cores running */ 105 SYSCTL_INT(_kern_smp, OID_AUTO, cores, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_ncores, 0, 106 "Number of CPUs online"); 107 108 int smp_topology = 0; /* Which topology we're using. */ 109 SYSCTL_INT(_kern_smp, OID_AUTO, topology, CTLFLAG_RDTUN, &smp_topology, 0, 110 "Topology override setting; 0 is default provided by hardware."); 111 112 #ifdef SMP 113 /* Enable forwarding of a signal to a process running on a different CPU */ 114 static int forward_signal_enabled = 1; 115 SYSCTL_INT(_kern_smp, OID_AUTO, forward_signal_enabled, CTLFLAG_RW, 116 &forward_signal_enabled, 0, 117 "Forwarding of a signal to a process on a different CPU"); 118 119 /* Variables needed for SMP rendezvous. */ 120 static volatile int smp_rv_ncpus; 121 static void (*volatile smp_rv_setup_func)(void *arg); 122 static void (*volatile smp_rv_action_func)(void *arg); 123 static void (*volatile smp_rv_teardown_func)(void *arg); 124 static void *volatile smp_rv_func_arg; 125 static volatile int smp_rv_waiters[4]; 126 127 /* 128 * Shared mutex to restrict busywaits between smp_rendezvous() and 129 * smp(_targeted)_tlb_shootdown(). A deadlock occurs if both of these 130 * functions trigger at once and cause multiple CPUs to busywait with 131 * interrupts disabled. 132 */ 133 struct mtx smp_ipi_mtx; 134 135 /* 136 * Let the MD SMP code initialize mp_maxid very early if it can. 137 */ 138 static void 139 mp_setmaxid(void *dummy) 140 { 141 142 cpu_mp_setmaxid(); 143 144 KASSERT(mp_ncpus >= 1, ("%s: CPU count < 1", __func__)); 145 KASSERT(mp_ncpus > 1 || mp_maxid == 0, 146 ("%s: one CPU but mp_maxid is not zero", __func__)); 147 KASSERT(mp_maxid >= mp_ncpus - 1, 148 ("%s: counters out of sync: max %d, count %d", __func__, 149 mp_maxid, mp_ncpus)); 150 } 151 SYSINIT(cpu_mp_setmaxid, SI_SUB_TUNABLES, SI_ORDER_FIRST, mp_setmaxid, NULL); 152 153 /* 154 * Call the MD SMP initialization code. 155 */ 156 static void 157 mp_start(void *dummy) 158 { 159 160 mtx_init(&smp_ipi_mtx, "smp rendezvous", NULL, MTX_SPIN); 161 162 /* Probe for MP hardware. */ 163 if (smp_disabled != 0 || cpu_mp_probe() == 0) { 164 mp_ncores = 1; 165 mp_ncpus = 1; 166 CPU_SETOF(PCPU_GET(cpuid), &all_cpus); 167 return; 168 } 169 170 cpu_mp_start(); 171 printf("FreeBSD/SMP: Multiprocessor System Detected: %d CPUs\n", 172 mp_ncpus); 173 174 /* Provide a default for most architectures that don't have SMT/HTT. */ 175 if (mp_ncores < 0) 176 mp_ncores = mp_ncpus; 177 178 cpu_mp_announce(); 179 } 180 SYSINIT(cpu_mp, SI_SUB_CPU, SI_ORDER_THIRD, mp_start, NULL); 181 182 void 183 forward_signal(struct thread *td) 184 { 185 int id; 186 187 /* 188 * signotify() has already set TDF_ASTPENDING and TDF_NEEDSIGCHECK on 189 * this thread, so all we need to do is poke it if it is currently 190 * executing so that it executes ast(). 191 */ 192 THREAD_LOCK_ASSERT(td, MA_OWNED); 193 KASSERT(TD_IS_RUNNING(td), 194 ("forward_signal: thread is not TDS_RUNNING")); 195 196 CTR1(KTR_SMP, "forward_signal(%p)", td->td_proc); 197 198 if (!smp_started || cold || panicstr) 199 return; 200 if (!forward_signal_enabled) 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 KASSERT(type == IPI_STOP || type == IPI_STOP_HARD 355 #if X86 356 || type == IPI_SUSPEND 357 #endif 358 , ("%s: invalid stop type", __func__)); 359 360 if (!smp_started) 361 return (0); 362 363 CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); 364 365 #if X86 366 if (type == IPI_SUSPEND) 367 cpus = &resuming_cpus; 368 else 369 #endif 370 cpus = &stopped_cpus; 371 372 /* signal other cpus to restart */ 373 #if X86 374 if (type == IPI_SUSPEND) 375 CPU_COPY_STORE_REL(&map, &toresume_cpus); 376 else 377 #endif 378 CPU_COPY_STORE_REL(&map, &started_cpus); 379 380 #if X86 381 if (!nmi_is_broadcast || nmi_kdb_lock == 0) { 382 #endif 383 /* wait for each to clear its bit */ 384 while (CPU_OVERLAP(cpus, &map)) 385 cpu_spinwait(); 386 #if X86 387 } 388 #endif 389 390 return (1); 391 } 392 393 int 394 restart_cpus(cpuset_t map) 395 { 396 397 return (generic_restart_cpus(map, IPI_STOP)); 398 } 399 400 #if X86 401 int 402 resume_cpus(cpuset_t map) 403 { 404 405 return (generic_restart_cpus(map, IPI_SUSPEND)); 406 } 407 #endif 408 #undef X86 409 410 /* 411 * All-CPU rendezvous. CPUs are signalled, all execute the setup function 412 * (if specified), rendezvous, execute the action function (if specified), 413 * rendezvous again, execute the teardown function (if specified), and then 414 * resume. 415 * 416 * Note that the supplied external functions _must_ be reentrant and aware 417 * that they are running in parallel and in an unknown lock context. 418 */ 419 void 420 smp_rendezvous_action(void) 421 { 422 struct thread *td; 423 void *local_func_arg; 424 void (*local_setup_func)(void*); 425 void (*local_action_func)(void*); 426 void (*local_teardown_func)(void*); 427 #ifdef INVARIANTS 428 int owepreempt; 429 #endif 430 431 /* Ensure we have up-to-date values. */ 432 atomic_add_acq_int(&smp_rv_waiters[0], 1); 433 while (smp_rv_waiters[0] < smp_rv_ncpus) 434 cpu_spinwait(); 435 436 /* Fetch rendezvous parameters after acquire barrier. */ 437 local_func_arg = smp_rv_func_arg; 438 local_setup_func = smp_rv_setup_func; 439 local_action_func = smp_rv_action_func; 440 local_teardown_func = smp_rv_teardown_func; 441 442 /* 443 * Use a nested critical section to prevent any preemptions 444 * from occurring during a rendezvous action routine. 445 * Specifically, if a rendezvous handler is invoked via an IPI 446 * and the interrupted thread was in the critical_exit() 447 * function after setting td_critnest to 0 but before 448 * performing a deferred preemption, this routine can be 449 * invoked with td_critnest set to 0 and td_owepreempt true. 450 * In that case, a critical_exit() during the rendezvous 451 * action would trigger a preemption which is not permitted in 452 * a rendezvous action. To fix this, wrap all of the 453 * rendezvous action handlers in a critical section. We 454 * cannot use a regular critical section however as having 455 * critical_exit() preempt from this routine would also be 456 * problematic (the preemption must not occur before the IPI 457 * has been acknowledged via an EOI). Instead, we 458 * intentionally ignore td_owepreempt when leaving the 459 * critical section. This should be harmless because we do 460 * not permit rendezvous action routines to schedule threads, 461 * and thus td_owepreempt should never transition from 0 to 1 462 * during this routine. 463 */ 464 td = curthread; 465 td->td_critnest++; 466 #ifdef INVARIANTS 467 owepreempt = td->td_owepreempt; 468 #endif 469 470 /* 471 * If requested, run a setup function before the main action 472 * function. Ensure all CPUs have completed the setup 473 * function before moving on to the action function. 474 */ 475 if (local_setup_func != smp_no_rendezvous_barrier) { 476 if (smp_rv_setup_func != NULL) 477 smp_rv_setup_func(smp_rv_func_arg); 478 atomic_add_int(&smp_rv_waiters[1], 1); 479 while (smp_rv_waiters[1] < smp_rv_ncpus) 480 cpu_spinwait(); 481 } 482 483 if (local_action_func != NULL) 484 local_action_func(local_func_arg); 485 486 if (local_teardown_func != smp_no_rendezvous_barrier) { 487 /* 488 * Signal that the main action has been completed. If a 489 * full exit rendezvous is requested, then all CPUs will 490 * wait here until all CPUs have finished the main action. 491 */ 492 atomic_add_int(&smp_rv_waiters[2], 1); 493 while (smp_rv_waiters[2] < smp_rv_ncpus) 494 cpu_spinwait(); 495 496 if (local_teardown_func != NULL) 497 local_teardown_func(local_func_arg); 498 } 499 500 /* 501 * Signal that the rendezvous is fully completed by this CPU. 502 * This means that no member of smp_rv_* pseudo-structure will be 503 * accessed by this target CPU after this point; in particular, 504 * memory pointed by smp_rv_func_arg. 505 * 506 * The release semantic ensures that all accesses performed by 507 * the current CPU are visible when smp_rendezvous_cpus() 508 * returns, by synchronizing with the 509 * atomic_load_acq_int(&smp_rv_waiters[3]). 510 */ 511 atomic_add_rel_int(&smp_rv_waiters[3], 1); 512 513 td->td_critnest--; 514 KASSERT(owepreempt == td->td_owepreempt, 515 ("rendezvous action changed td_owepreempt")); 516 } 517 518 void 519 smp_rendezvous_cpus(cpuset_t map, 520 void (* setup_func)(void *), 521 void (* action_func)(void *), 522 void (* teardown_func)(void *), 523 void *arg) 524 { 525 int curcpumap, i, ncpus = 0; 526 527 /* Look comments in the !SMP case. */ 528 if (!smp_started) { 529 spinlock_enter(); 530 if (setup_func != NULL) 531 setup_func(arg); 532 if (action_func != NULL) 533 action_func(arg); 534 if (teardown_func != NULL) 535 teardown_func(arg); 536 spinlock_exit(); 537 return; 538 } 539 540 CPU_FOREACH(i) { 541 if (CPU_ISSET(i, &map)) 542 ncpus++; 543 } 544 if (ncpus == 0) 545 panic("ncpus is 0 with non-zero map"); 546 547 mtx_lock_spin(&smp_ipi_mtx); 548 549 /* Pass rendezvous parameters via global variables. */ 550 smp_rv_ncpus = ncpus; 551 smp_rv_setup_func = setup_func; 552 smp_rv_action_func = action_func; 553 smp_rv_teardown_func = teardown_func; 554 smp_rv_func_arg = arg; 555 smp_rv_waiters[1] = 0; 556 smp_rv_waiters[2] = 0; 557 smp_rv_waiters[3] = 0; 558 atomic_store_rel_int(&smp_rv_waiters[0], 0); 559 560 /* 561 * Signal other processors, which will enter the IPI with 562 * interrupts off. 563 */ 564 curcpumap = CPU_ISSET(curcpu, &map); 565 CPU_CLR(curcpu, &map); 566 ipi_selected(map, IPI_RENDEZVOUS); 567 568 /* Check if the current CPU is in the map */ 569 if (curcpumap != 0) 570 smp_rendezvous_action(); 571 572 /* 573 * Ensure that the master CPU waits for all the other 574 * CPUs to finish the rendezvous, so that smp_rv_* 575 * pseudo-structure and the arg are guaranteed to not 576 * be in use. 577 * 578 * Load acquire synchronizes with the release add in 579 * smp_rendezvous_action(), which ensures that our caller sees 580 * all memory actions done by the called functions on other 581 * CPUs. 582 */ 583 while (atomic_load_acq_int(&smp_rv_waiters[3]) < ncpus) 584 cpu_spinwait(); 585 586 mtx_unlock_spin(&smp_ipi_mtx); 587 } 588 589 void 590 smp_rendezvous(void (* setup_func)(void *), 591 void (* action_func)(void *), 592 void (* teardown_func)(void *), 593 void *arg) 594 { 595 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); 596 } 597 598 static struct cpu_group group[MAXCPU * MAX_CACHE_LEVELS + 1]; 599 600 struct cpu_group * 601 smp_topo(void) 602 { 603 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 604 struct cpu_group *top; 605 606 /* 607 * Check for a fake topology request for debugging purposes. 608 */ 609 switch (smp_topology) { 610 case 1: 611 /* Dual core with no sharing. */ 612 top = smp_topo_1level(CG_SHARE_NONE, 2, 0); 613 break; 614 case 2: 615 /* No topology, all cpus are equal. */ 616 top = smp_topo_none(); 617 break; 618 case 3: 619 /* Dual core with shared L2. */ 620 top = smp_topo_1level(CG_SHARE_L2, 2, 0); 621 break; 622 case 4: 623 /* quad core, shared l3 among each package, private l2. */ 624 top = smp_topo_1level(CG_SHARE_L3, 4, 0); 625 break; 626 case 5: 627 /* quad core, 2 dualcore parts on each package share l2. */ 628 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); 629 break; 630 case 6: 631 /* Single-core 2xHTT */ 632 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); 633 break; 634 case 7: 635 /* quad core with a shared l3, 8 threads sharing L2. */ 636 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, 637 CG_FLAG_SMT); 638 break; 639 default: 640 /* Default, ask the system what it wants. */ 641 top = cpu_topo(); 642 break; 643 } 644 /* 645 * Verify the returned topology. 646 */ 647 if (top->cg_count != mp_ncpus) 648 panic("Built bad topology at %p. CPU count %d != %d", 649 top, top->cg_count, mp_ncpus); 650 if (CPU_CMP(&top->cg_mask, &all_cpus)) 651 panic("Built bad topology at %p. CPU mask (%s) != (%s)", 652 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), 653 cpusetobj_strprint(cpusetbuf2, &all_cpus)); 654 655 /* 656 * Collapse nonsense levels that may be created out of convenience by 657 * the MD layers. They cause extra work in the search functions. 658 */ 659 while (top->cg_children == 1) { 660 top = &top->cg_child[0]; 661 top->cg_parent = NULL; 662 } 663 return (top); 664 } 665 666 struct cpu_group * 667 smp_topo_alloc(u_int count) 668 { 669 static u_int index; 670 u_int curr; 671 672 curr = index; 673 index += count; 674 return (&group[curr]); 675 } 676 677 struct cpu_group * 678 smp_topo_none(void) 679 { 680 struct cpu_group *top; 681 682 top = &group[0]; 683 top->cg_parent = NULL; 684 top->cg_child = NULL; 685 top->cg_mask = all_cpus; 686 top->cg_count = mp_ncpus; 687 top->cg_children = 0; 688 top->cg_level = CG_SHARE_NONE; 689 top->cg_flags = 0; 690 691 return (top); 692 } 693 694 static int 695 smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, 696 int count, int flags, int start) 697 { 698 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 699 cpuset_t mask; 700 int i; 701 702 CPU_ZERO(&mask); 703 for (i = 0; i < count; i++, start++) 704 CPU_SET(start, &mask); 705 child->cg_parent = parent; 706 child->cg_child = NULL; 707 child->cg_children = 0; 708 child->cg_level = share; 709 child->cg_count = count; 710 child->cg_flags = flags; 711 child->cg_mask = mask; 712 parent->cg_children++; 713 for (; parent != NULL; parent = parent->cg_parent) { 714 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) 715 panic("Duplicate children in %p. mask (%s) child (%s)", 716 parent, 717 cpusetobj_strprint(cpusetbuf, &parent->cg_mask), 718 cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); 719 CPU_OR(&parent->cg_mask, &child->cg_mask); 720 parent->cg_count += child->cg_count; 721 } 722 723 return (start); 724 } 725 726 struct cpu_group * 727 smp_topo_1level(int share, int count, int flags) 728 { 729 struct cpu_group *child; 730 struct cpu_group *top; 731 int packages; 732 int cpu; 733 int i; 734 735 cpu = 0; 736 top = &group[0]; 737 packages = mp_ncpus / count; 738 top->cg_child = child = &group[1]; 739 top->cg_level = CG_SHARE_NONE; 740 for (i = 0; i < packages; i++, child++) 741 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); 742 return (top); 743 } 744 745 struct cpu_group * 746 smp_topo_2level(int l2share, int l2count, int l1share, int l1count, 747 int l1flags) 748 { 749 struct cpu_group *top; 750 struct cpu_group *l1g; 751 struct cpu_group *l2g; 752 int cpu; 753 int i; 754 int j; 755 756 cpu = 0; 757 top = &group[0]; 758 l2g = &group[1]; 759 top->cg_child = l2g; 760 top->cg_level = CG_SHARE_NONE; 761 top->cg_children = mp_ncpus / (l2count * l1count); 762 l1g = l2g + top->cg_children; 763 for (i = 0; i < top->cg_children; i++, l2g++) { 764 l2g->cg_parent = top; 765 l2g->cg_child = l1g; 766 l2g->cg_level = l2share; 767 for (j = 0; j < l2count; j++, l1g++) 768 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, 769 l1flags, cpu); 770 } 771 return (top); 772 } 773 774 775 struct cpu_group * 776 smp_topo_find(struct cpu_group *top, int cpu) 777 { 778 struct cpu_group *cg; 779 cpuset_t mask; 780 int children; 781 int i; 782 783 CPU_SETOF(cpu, &mask); 784 cg = top; 785 for (;;) { 786 if (!CPU_OVERLAP(&cg->cg_mask, &mask)) 787 return (NULL); 788 if (cg->cg_children == 0) 789 return (cg); 790 children = cg->cg_children; 791 for (i = 0, cg = cg->cg_child; i < children; cg++, i++) 792 if (CPU_OVERLAP(&cg->cg_mask, &mask)) 793 break; 794 } 795 return (NULL); 796 } 797 #else /* !SMP */ 798 799 void 800 smp_rendezvous_cpus(cpuset_t map, 801 void (*setup_func)(void *), 802 void (*action_func)(void *), 803 void (*teardown_func)(void *), 804 void *arg) 805 { 806 /* 807 * In the !SMP case we just need to ensure the same initial conditions 808 * as the SMP case. 809 */ 810 spinlock_enter(); 811 if (setup_func != NULL) 812 setup_func(arg); 813 if (action_func != NULL) 814 action_func(arg); 815 if (teardown_func != NULL) 816 teardown_func(arg); 817 spinlock_exit(); 818 } 819 820 void 821 smp_rendezvous(void (*setup_func)(void *), 822 void (*action_func)(void *), 823 void (*teardown_func)(void *), 824 void *arg) 825 { 826 827 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, 828 arg); 829 } 830 831 /* 832 * Provide dummy SMP support for UP kernels. Modules that need to use SMP 833 * APIs will still work using this dummy support. 834 */ 835 static void 836 mp_setvariables_for_up(void *dummy) 837 { 838 mp_ncpus = 1; 839 mp_ncores = 1; 840 mp_maxid = PCPU_GET(cpuid); 841 CPU_SETOF(mp_maxid, &all_cpus); 842 KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero")); 843 } 844 SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST, 845 mp_setvariables_for_up, NULL); 846 #endif /* SMP */ 847 848 void 849 smp_no_rendezvous_barrier(void *dummy) 850 { 851 #ifdef SMP 852 KASSERT((!smp_started),("smp_no_rendezvous called and smp is started")); 853 #endif 854 } 855 856 /* 857 * Wait for specified idle threads to switch once. This ensures that even 858 * preempted threads have cycled through the switch function once, 859 * exiting their codepaths. This allows us to change global pointers 860 * with no other synchronization. 861 */ 862 int 863 quiesce_cpus(cpuset_t map, const char *wmesg, int prio) 864 { 865 struct pcpu *pcpu; 866 u_int gen[MAXCPU]; 867 int error; 868 int cpu; 869 870 error = 0; 871 for (cpu = 0; cpu <= mp_maxid; cpu++) { 872 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 873 continue; 874 pcpu = pcpu_find(cpu); 875 gen[cpu] = pcpu->pc_idlethread->td_generation; 876 } 877 for (cpu = 0; cpu <= mp_maxid; cpu++) { 878 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 879 continue; 880 pcpu = pcpu_find(cpu); 881 thread_lock(curthread); 882 sched_bind(curthread, cpu); 883 thread_unlock(curthread); 884 while (gen[cpu] == pcpu->pc_idlethread->td_generation) { 885 error = tsleep(quiesce_cpus, prio, wmesg, 1); 886 if (error != EWOULDBLOCK) 887 goto out; 888 error = 0; 889 } 890 } 891 out: 892 thread_lock(curthread); 893 sched_unbind(curthread); 894 thread_unlock(curthread); 895 896 return (error); 897 } 898 899 int 900 quiesce_all_cpus(const char *wmesg, int prio) 901 { 902 903 return quiesce_cpus(all_cpus, wmesg, prio); 904 } 905 906 /* Extra care is taken with this sysctl because the data type is volatile */ 907 static int 908 sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS) 909 { 910 int error, active; 911 912 active = smp_started; 913 error = SYSCTL_OUT(req, &active, sizeof(active)); 914 return (error); 915 } 916 917 918 #ifdef SMP 919 void 920 topo_init_node(struct topo_node *node) 921 { 922 923 bzero(node, sizeof(*node)); 924 TAILQ_INIT(&node->children); 925 } 926 927 void 928 topo_init_root(struct topo_node *root) 929 { 930 931 topo_init_node(root); 932 root->type = TOPO_TYPE_SYSTEM; 933 } 934 935 /* 936 * Add a child node with the given ID under the given parent. 937 * Do nothing if there is already a child with that ID. 938 */ 939 struct topo_node * 940 topo_add_node_by_hwid(struct topo_node *parent, int hwid, 941 topo_node_type type, uintptr_t subtype) 942 { 943 struct topo_node *node; 944 945 TAILQ_FOREACH_REVERSE(node, &parent->children, 946 topo_children, siblings) { 947 if (node->hwid == hwid 948 && node->type == type && node->subtype == subtype) { 949 return (node); 950 } 951 } 952 953 node = malloc(sizeof(*node), M_TOPO, M_WAITOK); 954 topo_init_node(node); 955 node->parent = parent; 956 node->hwid = hwid; 957 node->type = type; 958 node->subtype = subtype; 959 TAILQ_INSERT_TAIL(&parent->children, node, siblings); 960 parent->nchildren++; 961 962 return (node); 963 } 964 965 /* 966 * Find a child node with the given ID under the given parent. 967 */ 968 struct topo_node * 969 topo_find_node_by_hwid(struct topo_node *parent, int hwid, 970 topo_node_type type, uintptr_t subtype) 971 { 972 973 struct topo_node *node; 974 975 TAILQ_FOREACH(node, &parent->children, siblings) { 976 if (node->hwid == hwid 977 && node->type == type && node->subtype == subtype) { 978 return (node); 979 } 980 } 981 982 return (NULL); 983 } 984 985 /* 986 * Given a node change the order of its parent's child nodes such 987 * that the node becomes the firt child while preserving the cyclic 988 * order of the children. In other words, the given node is promoted 989 * by rotation. 990 */ 991 void 992 topo_promote_child(struct topo_node *child) 993 { 994 struct topo_node *next; 995 struct topo_node *node; 996 struct topo_node *parent; 997 998 parent = child->parent; 999 next = TAILQ_NEXT(child, siblings); 1000 TAILQ_REMOVE(&parent->children, child, siblings); 1001 TAILQ_INSERT_HEAD(&parent->children, child, siblings); 1002 1003 while (next != NULL) { 1004 node = next; 1005 next = TAILQ_NEXT(node, siblings); 1006 TAILQ_REMOVE(&parent->children, node, siblings); 1007 TAILQ_INSERT_AFTER(&parent->children, child, node, siblings); 1008 child = node; 1009 } 1010 } 1011 1012 /* 1013 * Iterate to the next node in the depth-first search (traversal) of 1014 * the topology tree. 1015 */ 1016 struct topo_node * 1017 topo_next_node(struct topo_node *top, struct topo_node *node) 1018 { 1019 struct topo_node *next; 1020 1021 if ((next = TAILQ_FIRST(&node->children)) != NULL) 1022 return (next); 1023 1024 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1025 return (next); 1026 1027 while (node != top && (node = node->parent) != top) 1028 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1029 return (next); 1030 1031 return (NULL); 1032 } 1033 1034 /* 1035 * Iterate to the next node in the depth-first search of the topology tree, 1036 * but without descending below the current node. 1037 */ 1038 struct topo_node * 1039 topo_next_nonchild_node(struct topo_node *top, struct topo_node *node) 1040 { 1041 struct topo_node *next; 1042 1043 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1044 return (next); 1045 1046 while (node != top && (node = node->parent) != top) 1047 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1048 return (next); 1049 1050 return (NULL); 1051 } 1052 1053 /* 1054 * Assign the given ID to the given topology node that represents a logical 1055 * processor. 1056 */ 1057 void 1058 topo_set_pu_id(struct topo_node *node, cpuid_t id) 1059 { 1060 1061 KASSERT(node->type == TOPO_TYPE_PU, 1062 ("topo_set_pu_id: wrong node type: %u", node->type)); 1063 KASSERT(CPU_EMPTY(&node->cpuset) && node->cpu_count == 0, 1064 ("topo_set_pu_id: cpuset already not empty")); 1065 node->id = id; 1066 CPU_SET(id, &node->cpuset); 1067 node->cpu_count = 1; 1068 node->subtype = 1; 1069 1070 while ((node = node->parent) != NULL) { 1071 KASSERT(!CPU_ISSET(id, &node->cpuset), 1072 ("logical ID %u is already set in node %p", id, node)); 1073 CPU_SET(id, &node->cpuset); 1074 node->cpu_count++; 1075 } 1076 } 1077 1078 static struct topology_spec { 1079 topo_node_type type; 1080 bool match_subtype; 1081 uintptr_t subtype; 1082 } topology_level_table[TOPO_LEVEL_COUNT] = { 1083 [TOPO_LEVEL_PKG] = { .type = TOPO_TYPE_PKG, }, 1084 [TOPO_LEVEL_GROUP] = { .type = TOPO_TYPE_GROUP, }, 1085 [TOPO_LEVEL_CACHEGROUP] = { 1086 .type = TOPO_TYPE_CACHE, 1087 .match_subtype = true, 1088 .subtype = CG_SHARE_L3, 1089 }, 1090 [TOPO_LEVEL_CORE] = { .type = TOPO_TYPE_CORE, }, 1091 [TOPO_LEVEL_THREAD] = { .type = TOPO_TYPE_PU, }, 1092 }; 1093 1094 static bool 1095 topo_analyze_table(struct topo_node *root, int all, enum topo_level level, 1096 struct topo_analysis *results) 1097 { 1098 struct topology_spec *spec; 1099 struct topo_node *node; 1100 int count; 1101 1102 if (level >= TOPO_LEVEL_COUNT) 1103 return (true); 1104 1105 spec = &topology_level_table[level]; 1106 count = 0; 1107 node = topo_next_node(root, root); 1108 1109 while (node != NULL) { 1110 if (node->type != spec->type || 1111 (spec->match_subtype && node->subtype != spec->subtype)) { 1112 node = topo_next_node(root, node); 1113 continue; 1114 } 1115 if (!all && CPU_EMPTY(&node->cpuset)) { 1116 node = topo_next_nonchild_node(root, node); 1117 continue; 1118 } 1119 1120 count++; 1121 1122 if (!topo_analyze_table(node, all, level + 1, results)) 1123 return (false); 1124 1125 node = topo_next_nonchild_node(root, node); 1126 } 1127 1128 /* No explicit subgroups is essentially one subgroup. */ 1129 if (count == 0) { 1130 count = 1; 1131 1132 if (!topo_analyze_table(root, all, level + 1, results)) 1133 return (false); 1134 } 1135 1136 if (results->entities[level] == -1) 1137 results->entities[level] = count; 1138 else if (results->entities[level] != count) 1139 return (false); 1140 1141 return (true); 1142 } 1143 1144 /* 1145 * Check if the topology is uniform, that is, each package has the same number 1146 * of cores in it and each core has the same number of threads (logical 1147 * processors) in it. If so, calculate the number of packages, the number of 1148 * groups per package, the number of cachegroups per group, and the number of 1149 * logical processors per cachegroup. 'all' parameter tells whether to include 1150 * administratively disabled logical processors into the analysis. 1151 */ 1152 int 1153 topo_analyze(struct topo_node *topo_root, int all, 1154 struct topo_analysis *results) 1155 { 1156 1157 results->entities[TOPO_LEVEL_PKG] = -1; 1158 results->entities[TOPO_LEVEL_CORE] = -1; 1159 results->entities[TOPO_LEVEL_THREAD] = -1; 1160 results->entities[TOPO_LEVEL_GROUP] = -1; 1161 results->entities[TOPO_LEVEL_CACHEGROUP] = -1; 1162 1163 if (!topo_analyze_table(topo_root, all, TOPO_LEVEL_PKG, results)) 1164 return (0); 1165 1166 KASSERT(results->entities[TOPO_LEVEL_PKG] > 0, 1167 ("bug in topology or analysis")); 1168 1169 return (1); 1170 } 1171 1172 #endif /* SMP */ 1173 1174