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 #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 (smp_rv_setup_func != NULL) 503 smp_rv_setup_func(smp_rv_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 /* Look 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 CPU_FOREACH(i) { 567 if (CPU_ISSET(i, &map)) 568 ncpus++; 569 } 570 if (ncpus == 0) 571 panic("ncpus is 0 with non-zero map"); 572 573 mtx_lock_spin(&smp_ipi_mtx); 574 575 /* Pass rendezvous parameters via global variables. */ 576 smp_rv_ncpus = ncpus; 577 smp_rv_setup_func = setup_func; 578 smp_rv_action_func = action_func; 579 smp_rv_teardown_func = teardown_func; 580 smp_rv_func_arg = arg; 581 smp_rv_waiters[1] = 0; 582 smp_rv_waiters[2] = 0; 583 smp_rv_waiters[3] = 0; 584 atomic_store_rel_int(&smp_rv_waiters[0], 0); 585 586 /* 587 * Signal other processors, which will enter the IPI with 588 * interrupts off. 589 */ 590 curcpumap = CPU_ISSET(curcpu, &map); 591 CPU_CLR(curcpu, &map); 592 ipi_selected(map, IPI_RENDEZVOUS); 593 594 /* Check if the current CPU is in the map */ 595 if (curcpumap != 0) 596 smp_rendezvous_action(); 597 598 /* 599 * Ensure that the master CPU waits for all the other 600 * CPUs to finish the rendezvous, so that smp_rv_* 601 * pseudo-structure and the arg are guaranteed to not 602 * be in use. 603 * 604 * Load acquire synchronizes with the release add in 605 * smp_rendezvous_action(), which ensures that our caller sees 606 * all memory actions done by the called functions on other 607 * CPUs. 608 */ 609 while (atomic_load_acq_int(&smp_rv_waiters[3]) < ncpus) 610 cpu_spinwait(); 611 612 mtx_unlock_spin(&smp_ipi_mtx); 613 } 614 615 void 616 smp_rendezvous(void (* setup_func)(void *), 617 void (* action_func)(void *), 618 void (* teardown_func)(void *), 619 void *arg) 620 { 621 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); 622 } 623 624 static struct cpu_group group[MAXCPU * MAX_CACHE_LEVELS + 1]; 625 626 struct cpu_group * 627 smp_topo(void) 628 { 629 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 630 struct cpu_group *top; 631 632 /* 633 * Check for a fake topology request for debugging purposes. 634 */ 635 switch (smp_topology) { 636 case 1: 637 /* Dual core with no sharing. */ 638 top = smp_topo_1level(CG_SHARE_NONE, 2, 0); 639 break; 640 case 2: 641 /* No topology, all cpus are equal. */ 642 top = smp_topo_none(); 643 break; 644 case 3: 645 /* Dual core with shared L2. */ 646 top = smp_topo_1level(CG_SHARE_L2, 2, 0); 647 break; 648 case 4: 649 /* quad core, shared l3 among each package, private l2. */ 650 top = smp_topo_1level(CG_SHARE_L3, 4, 0); 651 break; 652 case 5: 653 /* quad core, 2 dualcore parts on each package share l2. */ 654 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); 655 break; 656 case 6: 657 /* Single-core 2xHTT */ 658 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); 659 break; 660 case 7: 661 /* quad core with a shared l3, 8 threads sharing L2. */ 662 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, 663 CG_FLAG_SMT); 664 break; 665 default: 666 /* Default, ask the system what it wants. */ 667 top = cpu_topo(); 668 break; 669 } 670 /* 671 * Verify the returned topology. 672 */ 673 if (top->cg_count != mp_ncpus) 674 panic("Built bad topology at %p. CPU count %d != %d", 675 top, top->cg_count, mp_ncpus); 676 if (CPU_CMP(&top->cg_mask, &all_cpus)) 677 panic("Built bad topology at %p. CPU mask (%s) != (%s)", 678 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), 679 cpusetobj_strprint(cpusetbuf2, &all_cpus)); 680 681 /* 682 * Collapse nonsense levels that may be created out of convenience by 683 * the MD layers. They cause extra work in the search functions. 684 */ 685 while (top->cg_children == 1) { 686 top = &top->cg_child[0]; 687 top->cg_parent = NULL; 688 } 689 return (top); 690 } 691 692 struct cpu_group * 693 smp_topo_alloc(u_int count) 694 { 695 static u_int index; 696 u_int curr; 697 698 curr = index; 699 index += count; 700 return (&group[curr]); 701 } 702 703 struct cpu_group * 704 smp_topo_none(void) 705 { 706 struct cpu_group *top; 707 708 top = &group[0]; 709 top->cg_parent = NULL; 710 top->cg_child = NULL; 711 top->cg_mask = all_cpus; 712 top->cg_count = mp_ncpus; 713 top->cg_children = 0; 714 top->cg_level = CG_SHARE_NONE; 715 top->cg_flags = 0; 716 717 return (top); 718 } 719 720 static int 721 smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, 722 int count, int flags, int start) 723 { 724 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 725 cpuset_t mask; 726 int i; 727 728 CPU_ZERO(&mask); 729 for (i = 0; i < count; i++, start++) 730 CPU_SET(start, &mask); 731 child->cg_parent = parent; 732 child->cg_child = NULL; 733 child->cg_children = 0; 734 child->cg_level = share; 735 child->cg_count = count; 736 child->cg_flags = flags; 737 child->cg_mask = mask; 738 parent->cg_children++; 739 for (; parent != NULL; parent = parent->cg_parent) { 740 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) 741 panic("Duplicate children in %p. mask (%s) child (%s)", 742 parent, 743 cpusetobj_strprint(cpusetbuf, &parent->cg_mask), 744 cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); 745 CPU_OR(&parent->cg_mask, &child->cg_mask); 746 parent->cg_count += child->cg_count; 747 } 748 749 return (start); 750 } 751 752 struct cpu_group * 753 smp_topo_1level(int share, int count, int flags) 754 { 755 struct cpu_group *child; 756 struct cpu_group *top; 757 int packages; 758 int cpu; 759 int i; 760 761 cpu = 0; 762 top = &group[0]; 763 packages = mp_ncpus / count; 764 top->cg_child = child = &group[1]; 765 top->cg_level = CG_SHARE_NONE; 766 for (i = 0; i < packages; i++, child++) 767 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); 768 return (top); 769 } 770 771 struct cpu_group * 772 smp_topo_2level(int l2share, int l2count, int l1share, int l1count, 773 int l1flags) 774 { 775 struct cpu_group *top; 776 struct cpu_group *l1g; 777 struct cpu_group *l2g; 778 int cpu; 779 int i; 780 int j; 781 782 cpu = 0; 783 top = &group[0]; 784 l2g = &group[1]; 785 top->cg_child = l2g; 786 top->cg_level = CG_SHARE_NONE; 787 top->cg_children = mp_ncpus / (l2count * l1count); 788 l1g = l2g + top->cg_children; 789 for (i = 0; i < top->cg_children; i++, l2g++) { 790 l2g->cg_parent = top; 791 l2g->cg_child = l1g; 792 l2g->cg_level = l2share; 793 for (j = 0; j < l2count; j++, l1g++) 794 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, 795 l1flags, cpu); 796 } 797 return (top); 798 } 799 800 801 struct cpu_group * 802 smp_topo_find(struct cpu_group *top, int cpu) 803 { 804 struct cpu_group *cg; 805 cpuset_t mask; 806 int children; 807 int i; 808 809 CPU_SETOF(cpu, &mask); 810 cg = top; 811 for (;;) { 812 if (!CPU_OVERLAP(&cg->cg_mask, &mask)) 813 return (NULL); 814 if (cg->cg_children == 0) 815 return (cg); 816 children = cg->cg_children; 817 for (i = 0, cg = cg->cg_child; i < children; cg++, i++) 818 if (CPU_OVERLAP(&cg->cg_mask, &mask)) 819 break; 820 } 821 return (NULL); 822 } 823 #else /* !SMP */ 824 825 void 826 smp_rendezvous_cpus(cpuset_t map, 827 void (*setup_func)(void *), 828 void (*action_func)(void *), 829 void (*teardown_func)(void *), 830 void *arg) 831 { 832 /* 833 * In the !SMP case we just need to ensure the same initial conditions 834 * as the SMP case. 835 */ 836 spinlock_enter(); 837 if (setup_func != NULL) 838 setup_func(arg); 839 if (action_func != NULL) 840 action_func(arg); 841 if (teardown_func != NULL) 842 teardown_func(arg); 843 spinlock_exit(); 844 } 845 846 void 847 smp_rendezvous(void (*setup_func)(void *), 848 void (*action_func)(void *), 849 void (*teardown_func)(void *), 850 void *arg) 851 { 852 853 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, 854 arg); 855 } 856 857 /* 858 * Provide dummy SMP support for UP kernels. Modules that need to use SMP 859 * APIs will still work using this dummy support. 860 */ 861 static void 862 mp_setvariables_for_up(void *dummy) 863 { 864 mp_ncpus = 1; 865 mp_ncores = 1; 866 mp_maxid = PCPU_GET(cpuid); 867 CPU_SETOF(mp_maxid, &all_cpus); 868 KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero")); 869 } 870 SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST, 871 mp_setvariables_for_up, NULL); 872 #endif /* SMP */ 873 874 void 875 smp_no_rendezvous_barrier(void *dummy) 876 { 877 #ifdef SMP 878 KASSERT((!smp_started),("smp_no_rendezvous called and smp is started")); 879 #endif 880 } 881 882 /* 883 * Wait for specified idle threads to switch once. This ensures that even 884 * preempted threads have cycled through the switch function once, 885 * exiting their codepaths. This allows us to change global pointers 886 * with no other synchronization. 887 */ 888 int 889 quiesce_cpus(cpuset_t map, const char *wmesg, int prio) 890 { 891 struct pcpu *pcpu; 892 u_int gen[MAXCPU]; 893 int error; 894 int cpu; 895 896 error = 0; 897 for (cpu = 0; cpu <= mp_maxid; cpu++) { 898 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 899 continue; 900 pcpu = pcpu_find(cpu); 901 gen[cpu] = pcpu->pc_idlethread->td_generation; 902 } 903 for (cpu = 0; cpu <= mp_maxid; cpu++) { 904 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 905 continue; 906 pcpu = pcpu_find(cpu); 907 thread_lock(curthread); 908 sched_bind(curthread, cpu); 909 thread_unlock(curthread); 910 while (gen[cpu] == pcpu->pc_idlethread->td_generation) { 911 error = tsleep(quiesce_cpus, prio, wmesg, 1); 912 if (error != EWOULDBLOCK) 913 goto out; 914 error = 0; 915 } 916 } 917 out: 918 thread_lock(curthread); 919 sched_unbind(curthread); 920 thread_unlock(curthread); 921 922 return (error); 923 } 924 925 int 926 quiesce_all_cpus(const char *wmesg, int prio) 927 { 928 929 return quiesce_cpus(all_cpus, wmesg, prio); 930 } 931 932 /* Extra care is taken with this sysctl because the data type is volatile */ 933 static int 934 sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS) 935 { 936 int error, active; 937 938 active = smp_started; 939 error = SYSCTL_OUT(req, &active, sizeof(active)); 940 return (error); 941 } 942 943 944 #ifdef SMP 945 void 946 topo_init_node(struct topo_node *node) 947 { 948 949 bzero(node, sizeof(*node)); 950 TAILQ_INIT(&node->children); 951 } 952 953 void 954 topo_init_root(struct topo_node *root) 955 { 956 957 topo_init_node(root); 958 root->type = TOPO_TYPE_SYSTEM; 959 } 960 961 /* 962 * Add a child node with the given ID under the given parent. 963 * Do nothing if there is already a child with that ID. 964 */ 965 struct topo_node * 966 topo_add_node_by_hwid(struct topo_node *parent, int hwid, 967 topo_node_type type, uintptr_t subtype) 968 { 969 struct topo_node *node; 970 971 TAILQ_FOREACH_REVERSE(node, &parent->children, 972 topo_children, siblings) { 973 if (node->hwid == hwid 974 && node->type == type && node->subtype == subtype) { 975 return (node); 976 } 977 } 978 979 node = malloc(sizeof(*node), M_TOPO, M_WAITOK); 980 topo_init_node(node); 981 node->parent = parent; 982 node->hwid = hwid; 983 node->type = type; 984 node->subtype = subtype; 985 TAILQ_INSERT_TAIL(&parent->children, node, siblings); 986 parent->nchildren++; 987 988 return (node); 989 } 990 991 /* 992 * Find a child node with the given ID under the given parent. 993 */ 994 struct topo_node * 995 topo_find_node_by_hwid(struct topo_node *parent, int hwid, 996 topo_node_type type, uintptr_t subtype) 997 { 998 999 struct topo_node *node; 1000 1001 TAILQ_FOREACH(node, &parent->children, siblings) { 1002 if (node->hwid == hwid 1003 && node->type == type && node->subtype == subtype) { 1004 return (node); 1005 } 1006 } 1007 1008 return (NULL); 1009 } 1010 1011 /* 1012 * Given a node change the order of its parent's child nodes such 1013 * that the node becomes the firt child while preserving the cyclic 1014 * order of the children. In other words, the given node is promoted 1015 * by rotation. 1016 */ 1017 void 1018 topo_promote_child(struct topo_node *child) 1019 { 1020 struct topo_node *next; 1021 struct topo_node *node; 1022 struct topo_node *parent; 1023 1024 parent = child->parent; 1025 next = TAILQ_NEXT(child, siblings); 1026 TAILQ_REMOVE(&parent->children, child, siblings); 1027 TAILQ_INSERT_HEAD(&parent->children, child, siblings); 1028 1029 while (next != NULL) { 1030 node = next; 1031 next = TAILQ_NEXT(node, siblings); 1032 TAILQ_REMOVE(&parent->children, node, siblings); 1033 TAILQ_INSERT_AFTER(&parent->children, child, node, siblings); 1034 child = node; 1035 } 1036 } 1037 1038 /* 1039 * Iterate to the next node in the depth-first search (traversal) of 1040 * the topology tree. 1041 */ 1042 struct topo_node * 1043 topo_next_node(struct topo_node *top, struct topo_node *node) 1044 { 1045 struct topo_node *next; 1046 1047 if ((next = TAILQ_FIRST(&node->children)) != NULL) 1048 return (next); 1049 1050 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1051 return (next); 1052 1053 while (node != top && (node = node->parent) != top) 1054 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1055 return (next); 1056 1057 return (NULL); 1058 } 1059 1060 /* 1061 * Iterate to the next node in the depth-first search of the topology tree, 1062 * but without descending below the current node. 1063 */ 1064 struct topo_node * 1065 topo_next_nonchild_node(struct topo_node *top, struct topo_node *node) 1066 { 1067 struct topo_node *next; 1068 1069 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1070 return (next); 1071 1072 while (node != top && (node = node->parent) != top) 1073 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1074 return (next); 1075 1076 return (NULL); 1077 } 1078 1079 /* 1080 * Assign the given ID to the given topology node that represents a logical 1081 * processor. 1082 */ 1083 void 1084 topo_set_pu_id(struct topo_node *node, cpuid_t id) 1085 { 1086 1087 KASSERT(node->type == TOPO_TYPE_PU, 1088 ("topo_set_pu_id: wrong node type: %u", node->type)); 1089 KASSERT(CPU_EMPTY(&node->cpuset) && node->cpu_count == 0, 1090 ("topo_set_pu_id: cpuset already not empty")); 1091 node->id = id; 1092 CPU_SET(id, &node->cpuset); 1093 node->cpu_count = 1; 1094 node->subtype = 1; 1095 1096 while ((node = node->parent) != NULL) { 1097 KASSERT(!CPU_ISSET(id, &node->cpuset), 1098 ("logical ID %u is already set in node %p", id, node)); 1099 CPU_SET(id, &node->cpuset); 1100 node->cpu_count++; 1101 } 1102 } 1103 1104 static struct topology_spec { 1105 topo_node_type type; 1106 bool match_subtype; 1107 uintptr_t subtype; 1108 } topology_level_table[TOPO_LEVEL_COUNT] = { 1109 [TOPO_LEVEL_PKG] = { .type = TOPO_TYPE_PKG, }, 1110 [TOPO_LEVEL_GROUP] = { .type = TOPO_TYPE_GROUP, }, 1111 [TOPO_LEVEL_CACHEGROUP] = { 1112 .type = TOPO_TYPE_CACHE, 1113 .match_subtype = true, 1114 .subtype = CG_SHARE_L3, 1115 }, 1116 [TOPO_LEVEL_CORE] = { .type = TOPO_TYPE_CORE, }, 1117 [TOPO_LEVEL_THREAD] = { .type = TOPO_TYPE_PU, }, 1118 }; 1119 1120 static bool 1121 topo_analyze_table(struct topo_node *root, int all, enum topo_level level, 1122 struct topo_analysis *results) 1123 { 1124 struct topology_spec *spec; 1125 struct topo_node *node; 1126 int count; 1127 1128 if (level >= TOPO_LEVEL_COUNT) 1129 return (true); 1130 1131 spec = &topology_level_table[level]; 1132 count = 0; 1133 node = topo_next_node(root, root); 1134 1135 while (node != NULL) { 1136 if (node->type != spec->type || 1137 (spec->match_subtype && node->subtype != spec->subtype)) { 1138 node = topo_next_node(root, node); 1139 continue; 1140 } 1141 if (!all && CPU_EMPTY(&node->cpuset)) { 1142 node = topo_next_nonchild_node(root, node); 1143 continue; 1144 } 1145 1146 count++; 1147 1148 if (!topo_analyze_table(node, all, level + 1, results)) 1149 return (false); 1150 1151 node = topo_next_nonchild_node(root, node); 1152 } 1153 1154 /* No explicit subgroups is essentially one subgroup. */ 1155 if (count == 0) { 1156 count = 1; 1157 1158 if (!topo_analyze_table(root, all, level + 1, results)) 1159 return (false); 1160 } 1161 1162 if (results->entities[level] == -1) 1163 results->entities[level] = count; 1164 else if (results->entities[level] != count) 1165 return (false); 1166 1167 return (true); 1168 } 1169 1170 /* 1171 * Check if the topology is uniform, that is, each package has the same number 1172 * of cores in it and each core has the same number of threads (logical 1173 * processors) in it. If so, calculate the number of packages, the number of 1174 * groups per package, the number of cachegroups per group, and the number of 1175 * logical processors per cachegroup. 'all' parameter tells whether to include 1176 * administratively disabled logical processors into the analysis. 1177 */ 1178 int 1179 topo_analyze(struct topo_node *topo_root, int all, 1180 struct topo_analysis *results) 1181 { 1182 1183 results->entities[TOPO_LEVEL_PKG] = -1; 1184 results->entities[TOPO_LEVEL_CORE] = -1; 1185 results->entities[TOPO_LEVEL_THREAD] = -1; 1186 results->entities[TOPO_LEVEL_GROUP] = -1; 1187 results->entities[TOPO_LEVEL_CACHEGROUP] = -1; 1188 1189 if (!topo_analyze_table(topo_root, all, TOPO_LEVEL_PKG, results)) 1190 return (0); 1191 1192 KASSERT(results->entities[TOPO_LEVEL_PKG] > 0, 1193 ("bug in topology or analysis")); 1194 1195 return (1); 1196 } 1197 1198 #endif /* SMP */ 1199 1200