1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2001, John Baldwin <jhb@FreeBSD.org>. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 /* 30 * This module holds the global variables and machine independent functions 31 * used for the kernel SMP support. 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/kernel.h> 40 #include <sys/ktr.h> 41 #include <sys/proc.h> 42 #include <sys/bus.h> 43 #include <sys/lock.h> 44 #include <sys/malloc.h> 45 #include <sys/mutex.h> 46 #include <sys/pcpu.h> 47 #include <sys/sched.h> 48 #include <sys/smp.h> 49 #include <sys/sysctl.h> 50 51 #include <machine/cpu.h> 52 #include <machine/smp.h> 53 54 #include "opt_sched.h" 55 56 #ifdef SMP 57 MALLOC_DEFINE(M_TOPO, "toponodes", "SMP topology data"); 58 59 volatile cpuset_t stopped_cpus; 60 volatile cpuset_t started_cpus; 61 volatile cpuset_t suspended_cpus; 62 cpuset_t hlt_cpus_mask; 63 cpuset_t logical_cpus_mask; 64 65 void (*cpustop_restartfunc)(void); 66 #endif 67 68 static int sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS); 69 70 /* This is used in modules that need to work in both SMP and UP. */ 71 cpuset_t all_cpus; 72 73 int mp_ncpus; 74 /* export this for libkvm consumers. */ 75 int mp_maxcpus = MAXCPU; 76 77 volatile int smp_started; 78 u_int mp_maxid; 79 80 static SYSCTL_NODE(_kern, OID_AUTO, smp, CTLFLAG_RD|CTLFLAG_CAPRD, NULL, 81 "Kernel SMP"); 82 83 SYSCTL_INT(_kern_smp, OID_AUTO, maxid, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxid, 0, 84 "Max CPU ID."); 85 86 SYSCTL_INT(_kern_smp, OID_AUTO, maxcpus, CTLFLAG_RD|CTLFLAG_CAPRD, &mp_maxcpus, 87 0, "Max number of CPUs that the system was compiled for."); 88 89 SYSCTL_PROC(_kern_smp, OID_AUTO, active, CTLFLAG_RD|CTLTYPE_INT|CTLFLAG_MPSAFE, 90 NULL, 0, sysctl_kern_smp_active, "I", 91 "Indicates system is running in SMP mode"); 92 93 int smp_disabled = 0; /* has smp been disabled? */ 94 SYSCTL_INT(_kern_smp, OID_AUTO, disabled, CTLFLAG_RDTUN|CTLFLAG_CAPRD, 95 &smp_disabled, 0, "SMP has been disabled from the loader"); 96 97 int smp_cpus = 1; /* how many cpu's running */ 98 SYSCTL_INT(_kern_smp, OID_AUTO, cpus, CTLFLAG_RD|CTLFLAG_CAPRD, &smp_cpus, 0, 99 "Number of CPUs online"); 100 101 int smp_topology = 0; /* Which topology we're using. */ 102 SYSCTL_INT(_kern_smp, OID_AUTO, topology, CTLFLAG_RDTUN, &smp_topology, 0, 103 "Topology override setting; 0 is default provided by hardware."); 104 105 #ifdef SMP 106 /* Enable forwarding of a signal to a process running on a different CPU */ 107 static int forward_signal_enabled = 1; 108 SYSCTL_INT(_kern_smp, OID_AUTO, forward_signal_enabled, CTLFLAG_RW, 109 &forward_signal_enabled, 0, 110 "Forwarding of a signal to a process on a different CPU"); 111 112 /* Variables needed for SMP rendezvous. */ 113 static volatile int smp_rv_ncpus; 114 static void (*volatile smp_rv_setup_func)(void *arg); 115 static void (*volatile smp_rv_action_func)(void *arg); 116 static void (*volatile smp_rv_teardown_func)(void *arg); 117 static void *volatile smp_rv_func_arg; 118 static volatile int smp_rv_waiters[4]; 119 120 /* 121 * Shared mutex to restrict busywaits between smp_rendezvous() and 122 * smp(_targeted)_tlb_shootdown(). A deadlock occurs if both of these 123 * functions trigger at once and cause multiple CPUs to busywait with 124 * interrupts disabled. 125 */ 126 struct mtx smp_ipi_mtx; 127 128 /* 129 * Let the MD SMP code initialize mp_maxid very early if it can. 130 */ 131 static void 132 mp_setmaxid(void *dummy) 133 { 134 135 cpu_mp_setmaxid(); 136 137 KASSERT(mp_ncpus >= 1, ("%s: CPU count < 1", __func__)); 138 KASSERT(mp_ncpus > 1 || mp_maxid == 0, 139 ("%s: one CPU but mp_maxid is not zero", __func__)); 140 KASSERT(mp_maxid >= mp_ncpus - 1, 141 ("%s: counters out of sync: max %d, count %d", __func__, 142 mp_maxid, mp_ncpus)); 143 } 144 SYSINIT(cpu_mp_setmaxid, SI_SUB_TUNABLES, SI_ORDER_FIRST, mp_setmaxid, NULL); 145 146 /* 147 * Call the MD SMP initialization code. 148 */ 149 static void 150 mp_start(void *dummy) 151 { 152 153 mtx_init(&smp_ipi_mtx, "smp rendezvous", NULL, MTX_SPIN); 154 155 /* Probe for MP hardware. */ 156 if (smp_disabled != 0 || cpu_mp_probe() == 0) { 157 mp_ncpus = 1; 158 CPU_SETOF(PCPU_GET(cpuid), &all_cpus); 159 return; 160 } 161 162 cpu_mp_start(); 163 printf("FreeBSD/SMP: Multiprocessor System Detected: %d CPUs\n", 164 mp_ncpus); 165 cpu_mp_announce(); 166 } 167 SYSINIT(cpu_mp, SI_SUB_CPU, SI_ORDER_THIRD, mp_start, NULL); 168 169 void 170 forward_signal(struct thread *td) 171 { 172 int id; 173 174 /* 175 * signotify() has already set TDF_ASTPENDING and TDF_NEEDSIGCHECK on 176 * this thread, so all we need to do is poke it if it is currently 177 * executing so that it executes ast(). 178 */ 179 THREAD_LOCK_ASSERT(td, MA_OWNED); 180 KASSERT(TD_IS_RUNNING(td), 181 ("forward_signal: thread is not TDS_RUNNING")); 182 183 CTR1(KTR_SMP, "forward_signal(%p)", td->td_proc); 184 185 if (!smp_started || cold || panicstr) 186 return; 187 if (!forward_signal_enabled) 188 return; 189 190 /* No need to IPI ourself. */ 191 if (td == curthread) 192 return; 193 194 id = td->td_oncpu; 195 if (id == NOCPU) 196 return; 197 ipi_cpu(id, IPI_AST); 198 } 199 200 /* 201 * When called the executing CPU will send an IPI to all other CPUs 202 * requesting that they halt execution. 203 * 204 * Usually (but not necessarily) called with 'other_cpus' as its arg. 205 * 206 * - Signals all CPUs in map to stop. 207 * - Waits for each to stop. 208 * 209 * Returns: 210 * -1: error 211 * 0: NA 212 * 1: ok 213 * 214 */ 215 #if defined(__amd64__) || defined(__i386__) 216 #define X86 1 217 #else 218 #define X86 0 219 #endif 220 static int 221 generic_stop_cpus(cpuset_t map, u_int type) 222 { 223 #ifdef KTR 224 char cpusetbuf[CPUSETBUFSIZ]; 225 #endif 226 static volatile u_int stopping_cpu = NOCPU; 227 int i; 228 volatile cpuset_t *cpus; 229 230 KASSERT( 231 type == IPI_STOP || type == IPI_STOP_HARD 232 #if X86 233 || type == IPI_SUSPEND 234 #endif 235 , ("%s: invalid stop type", __func__)); 236 237 if (!smp_started) 238 return (0); 239 240 CTR2(KTR_SMP, "stop_cpus(%s) with %u type", 241 cpusetobj_strprint(cpusetbuf, &map), type); 242 243 #if X86 244 /* 245 * When suspending, ensure there are are no IPIs in progress. 246 * IPIs that have been issued, but not yet delivered (e.g. 247 * not pending on a vCPU when running under virtualization) 248 * will be lost, violating FreeBSD's assumption of reliable 249 * IPI delivery. 250 */ 251 if (type == IPI_SUSPEND) 252 mtx_lock_spin(&smp_ipi_mtx); 253 #endif 254 255 #if X86 256 if (!nmi_is_broadcast || nmi_kdb_lock == 0) { 257 #endif 258 if (stopping_cpu != PCPU_GET(cpuid)) 259 while (atomic_cmpset_int(&stopping_cpu, NOCPU, 260 PCPU_GET(cpuid)) == 0) 261 while (stopping_cpu != NOCPU) 262 cpu_spinwait(); /* spin */ 263 264 /* send the stop IPI to all CPUs in map */ 265 ipi_selected(map, type); 266 #if X86 267 } 268 #endif 269 270 #if X86 271 if (type == IPI_SUSPEND) 272 cpus = &suspended_cpus; 273 else 274 #endif 275 cpus = &stopped_cpus; 276 277 i = 0; 278 while (!CPU_SUBSET(cpus, &map)) { 279 /* spin */ 280 cpu_spinwait(); 281 i++; 282 if (i == 100000000) { 283 printf("timeout stopping cpus\n"); 284 break; 285 } 286 } 287 288 #if X86 289 if (type == IPI_SUSPEND) 290 mtx_unlock_spin(&smp_ipi_mtx); 291 #endif 292 293 stopping_cpu = NOCPU; 294 return (1); 295 } 296 297 int 298 stop_cpus(cpuset_t map) 299 { 300 301 return (generic_stop_cpus(map, IPI_STOP)); 302 } 303 304 int 305 stop_cpus_hard(cpuset_t map) 306 { 307 308 return (generic_stop_cpus(map, IPI_STOP_HARD)); 309 } 310 311 #if X86 312 int 313 suspend_cpus(cpuset_t map) 314 { 315 316 return (generic_stop_cpus(map, IPI_SUSPEND)); 317 } 318 #endif 319 320 /* 321 * Called by a CPU to restart stopped CPUs. 322 * 323 * Usually (but not necessarily) called with 'stopped_cpus' as its arg. 324 * 325 * - Signals all CPUs in map to restart. 326 * - Waits for each to restart. 327 * 328 * Returns: 329 * -1: error 330 * 0: NA 331 * 1: ok 332 */ 333 static int 334 generic_restart_cpus(cpuset_t map, u_int type) 335 { 336 #ifdef KTR 337 char cpusetbuf[CPUSETBUFSIZ]; 338 #endif 339 volatile cpuset_t *cpus; 340 341 KASSERT(type == IPI_STOP || type == IPI_STOP_HARD 342 #if X86 343 || type == IPI_SUSPEND 344 #endif 345 , ("%s: invalid stop type", __func__)); 346 347 if (!smp_started) 348 return (0); 349 350 CTR1(KTR_SMP, "restart_cpus(%s)", cpusetobj_strprint(cpusetbuf, &map)); 351 352 #if X86 353 if (type == IPI_SUSPEND) 354 cpus = &resuming_cpus; 355 else 356 #endif 357 cpus = &stopped_cpus; 358 359 /* signal other cpus to restart */ 360 #if X86 361 if (type == IPI_SUSPEND) 362 CPU_COPY_STORE_REL(&map, &toresume_cpus); 363 else 364 #endif 365 CPU_COPY_STORE_REL(&map, &started_cpus); 366 367 #if X86 368 if (!nmi_is_broadcast || nmi_kdb_lock == 0) { 369 #endif 370 /* wait for each to clear its bit */ 371 while (CPU_OVERLAP(cpus, &map)) 372 cpu_spinwait(); 373 #if X86 374 } 375 #endif 376 377 return (1); 378 } 379 380 int 381 restart_cpus(cpuset_t map) 382 { 383 384 return (generic_restart_cpus(map, IPI_STOP)); 385 } 386 387 #if X86 388 int 389 resume_cpus(cpuset_t map) 390 { 391 392 return (generic_restart_cpus(map, IPI_SUSPEND)); 393 } 394 #endif 395 #undef X86 396 397 /* 398 * All-CPU rendezvous. CPUs are signalled, all execute the setup function 399 * (if specified), rendezvous, execute the action function (if specified), 400 * rendezvous again, execute the teardown function (if specified), and then 401 * resume. 402 * 403 * Note that the supplied external functions _must_ be reentrant and aware 404 * that they are running in parallel and in an unknown lock context. 405 */ 406 void 407 smp_rendezvous_action(void) 408 { 409 struct thread *td; 410 void *local_func_arg; 411 void (*local_setup_func)(void*); 412 void (*local_action_func)(void*); 413 void (*local_teardown_func)(void*); 414 #ifdef INVARIANTS 415 int owepreempt; 416 #endif 417 418 /* Ensure we have up-to-date values. */ 419 atomic_add_acq_int(&smp_rv_waiters[0], 1); 420 while (smp_rv_waiters[0] < smp_rv_ncpus) 421 cpu_spinwait(); 422 423 /* Fetch rendezvous parameters after acquire barrier. */ 424 local_func_arg = smp_rv_func_arg; 425 local_setup_func = smp_rv_setup_func; 426 local_action_func = smp_rv_action_func; 427 local_teardown_func = smp_rv_teardown_func; 428 429 /* 430 * Use a nested critical section to prevent any preemptions 431 * from occurring during a rendezvous action routine. 432 * Specifically, if a rendezvous handler is invoked via an IPI 433 * and the interrupted thread was in the critical_exit() 434 * function after setting td_critnest to 0 but before 435 * performing a deferred preemption, this routine can be 436 * invoked with td_critnest set to 0 and td_owepreempt true. 437 * In that case, a critical_exit() during the rendezvous 438 * action would trigger a preemption which is not permitted in 439 * a rendezvous action. To fix this, wrap all of the 440 * rendezvous action handlers in a critical section. We 441 * cannot use a regular critical section however as having 442 * critical_exit() preempt from this routine would also be 443 * problematic (the preemption must not occur before the IPI 444 * has been acknowledged via an EOI). Instead, we 445 * intentionally ignore td_owepreempt when leaving the 446 * critical section. This should be harmless because we do 447 * not permit rendezvous action routines to schedule threads, 448 * and thus td_owepreempt should never transition from 0 to 1 449 * during this routine. 450 */ 451 td = curthread; 452 td->td_critnest++; 453 #ifdef INVARIANTS 454 owepreempt = td->td_owepreempt; 455 #endif 456 457 /* 458 * If requested, run a setup function before the main action 459 * function. Ensure all CPUs have completed the setup 460 * function before moving on to the action function. 461 */ 462 if (local_setup_func != smp_no_rendezvous_barrier) { 463 if (smp_rv_setup_func != NULL) 464 smp_rv_setup_func(smp_rv_func_arg); 465 atomic_add_int(&smp_rv_waiters[1], 1); 466 while (smp_rv_waiters[1] < smp_rv_ncpus) 467 cpu_spinwait(); 468 } 469 470 if (local_action_func != NULL) 471 local_action_func(local_func_arg); 472 473 if (local_teardown_func != smp_no_rendezvous_barrier) { 474 /* 475 * Signal that the main action has been completed. If a 476 * full exit rendezvous is requested, then all CPUs will 477 * wait here until all CPUs have finished the main action. 478 */ 479 atomic_add_int(&smp_rv_waiters[2], 1); 480 while (smp_rv_waiters[2] < smp_rv_ncpus) 481 cpu_spinwait(); 482 483 if (local_teardown_func != NULL) 484 local_teardown_func(local_func_arg); 485 } 486 487 /* 488 * Signal that the rendezvous is fully completed by this CPU. 489 * This means that no member of smp_rv_* pseudo-structure will be 490 * accessed by this target CPU after this point; in particular, 491 * memory pointed by smp_rv_func_arg. 492 * 493 * The release semantic ensures that all accesses performed by 494 * the current CPU are visible when smp_rendezvous_cpus() 495 * returns, by synchronizing with the 496 * atomic_load_acq_int(&smp_rv_waiters[3]). 497 */ 498 atomic_add_rel_int(&smp_rv_waiters[3], 1); 499 500 td->td_critnest--; 501 KASSERT(owepreempt == td->td_owepreempt, 502 ("rendezvous action changed td_owepreempt")); 503 } 504 505 void 506 smp_rendezvous_cpus(cpuset_t map, 507 void (* setup_func)(void *), 508 void (* action_func)(void *), 509 void (* teardown_func)(void *), 510 void *arg) 511 { 512 int curcpumap, i, ncpus = 0; 513 514 /* Look comments in the !SMP case. */ 515 if (!smp_started) { 516 spinlock_enter(); 517 if (setup_func != NULL) 518 setup_func(arg); 519 if (action_func != NULL) 520 action_func(arg); 521 if (teardown_func != NULL) 522 teardown_func(arg); 523 spinlock_exit(); 524 return; 525 } 526 527 CPU_FOREACH(i) { 528 if (CPU_ISSET(i, &map)) 529 ncpus++; 530 } 531 if (ncpus == 0) 532 panic("ncpus is 0 with non-zero map"); 533 534 mtx_lock_spin(&smp_ipi_mtx); 535 536 /* Pass rendezvous parameters via global variables. */ 537 smp_rv_ncpus = ncpus; 538 smp_rv_setup_func = setup_func; 539 smp_rv_action_func = action_func; 540 smp_rv_teardown_func = teardown_func; 541 smp_rv_func_arg = arg; 542 smp_rv_waiters[1] = 0; 543 smp_rv_waiters[2] = 0; 544 smp_rv_waiters[3] = 0; 545 atomic_store_rel_int(&smp_rv_waiters[0], 0); 546 547 /* 548 * Signal other processors, which will enter the IPI with 549 * interrupts off. 550 */ 551 curcpumap = CPU_ISSET(curcpu, &map); 552 CPU_CLR(curcpu, &map); 553 ipi_selected(map, IPI_RENDEZVOUS); 554 555 /* Check if the current CPU is in the map */ 556 if (curcpumap != 0) 557 smp_rendezvous_action(); 558 559 /* 560 * Ensure that the master CPU waits for all the other 561 * CPUs to finish the rendezvous, so that smp_rv_* 562 * pseudo-structure and the arg are guaranteed to not 563 * be in use. 564 * 565 * Load acquire synchronizes with the release add in 566 * smp_rendezvous_action(), which ensures that our caller sees 567 * all memory actions done by the called functions on other 568 * CPUs. 569 */ 570 while (atomic_load_acq_int(&smp_rv_waiters[3]) < ncpus) 571 cpu_spinwait(); 572 573 mtx_unlock_spin(&smp_ipi_mtx); 574 } 575 576 void 577 smp_rendezvous(void (* setup_func)(void *), 578 void (* action_func)(void *), 579 void (* teardown_func)(void *), 580 void *arg) 581 { 582 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg); 583 } 584 585 static struct cpu_group group[MAXCPU * MAX_CACHE_LEVELS + 1]; 586 587 struct cpu_group * 588 smp_topo(void) 589 { 590 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 591 struct cpu_group *top; 592 593 /* 594 * Check for a fake topology request for debugging purposes. 595 */ 596 switch (smp_topology) { 597 case 1: 598 /* Dual core with no sharing. */ 599 top = smp_topo_1level(CG_SHARE_NONE, 2, 0); 600 break; 601 case 2: 602 /* No topology, all cpus are equal. */ 603 top = smp_topo_none(); 604 break; 605 case 3: 606 /* Dual core with shared L2. */ 607 top = smp_topo_1level(CG_SHARE_L2, 2, 0); 608 break; 609 case 4: 610 /* quad core, shared l3 among each package, private l2. */ 611 top = smp_topo_1level(CG_SHARE_L3, 4, 0); 612 break; 613 case 5: 614 /* quad core, 2 dualcore parts on each package share l2. */ 615 top = smp_topo_2level(CG_SHARE_NONE, 2, CG_SHARE_L2, 2, 0); 616 break; 617 case 6: 618 /* Single-core 2xHTT */ 619 top = smp_topo_1level(CG_SHARE_L1, 2, CG_FLAG_HTT); 620 break; 621 case 7: 622 /* quad core with a shared l3, 8 threads sharing L2. */ 623 top = smp_topo_2level(CG_SHARE_L3, 4, CG_SHARE_L2, 8, 624 CG_FLAG_SMT); 625 break; 626 default: 627 /* Default, ask the system what it wants. */ 628 top = cpu_topo(); 629 break; 630 } 631 /* 632 * Verify the returned topology. 633 */ 634 if (top->cg_count != mp_ncpus) 635 panic("Built bad topology at %p. CPU count %d != %d", 636 top, top->cg_count, mp_ncpus); 637 if (CPU_CMP(&top->cg_mask, &all_cpus)) 638 panic("Built bad topology at %p. CPU mask (%s) != (%s)", 639 top, cpusetobj_strprint(cpusetbuf, &top->cg_mask), 640 cpusetobj_strprint(cpusetbuf2, &all_cpus)); 641 642 /* 643 * Collapse nonsense levels that may be created out of convenience by 644 * the MD layers. They cause extra work in the search functions. 645 */ 646 while (top->cg_children == 1) { 647 top = &top->cg_child[0]; 648 top->cg_parent = NULL; 649 } 650 return (top); 651 } 652 653 struct cpu_group * 654 smp_topo_alloc(u_int count) 655 { 656 static u_int index; 657 u_int curr; 658 659 curr = index; 660 index += count; 661 return (&group[curr]); 662 } 663 664 struct cpu_group * 665 smp_topo_none(void) 666 { 667 struct cpu_group *top; 668 669 top = &group[0]; 670 top->cg_parent = NULL; 671 top->cg_child = NULL; 672 top->cg_mask = all_cpus; 673 top->cg_count = mp_ncpus; 674 top->cg_children = 0; 675 top->cg_level = CG_SHARE_NONE; 676 top->cg_flags = 0; 677 678 return (top); 679 } 680 681 static int 682 smp_topo_addleaf(struct cpu_group *parent, struct cpu_group *child, int share, 683 int count, int flags, int start) 684 { 685 char cpusetbuf[CPUSETBUFSIZ], cpusetbuf2[CPUSETBUFSIZ]; 686 cpuset_t mask; 687 int i; 688 689 CPU_ZERO(&mask); 690 for (i = 0; i < count; i++, start++) 691 CPU_SET(start, &mask); 692 child->cg_parent = parent; 693 child->cg_child = NULL; 694 child->cg_children = 0; 695 child->cg_level = share; 696 child->cg_count = count; 697 child->cg_flags = flags; 698 child->cg_mask = mask; 699 parent->cg_children++; 700 for (; parent != NULL; parent = parent->cg_parent) { 701 if (CPU_OVERLAP(&parent->cg_mask, &child->cg_mask)) 702 panic("Duplicate children in %p. mask (%s) child (%s)", 703 parent, 704 cpusetobj_strprint(cpusetbuf, &parent->cg_mask), 705 cpusetobj_strprint(cpusetbuf2, &child->cg_mask)); 706 CPU_OR(&parent->cg_mask, &child->cg_mask); 707 parent->cg_count += child->cg_count; 708 } 709 710 return (start); 711 } 712 713 struct cpu_group * 714 smp_topo_1level(int share, int count, int flags) 715 { 716 struct cpu_group *child; 717 struct cpu_group *top; 718 int packages; 719 int cpu; 720 int i; 721 722 cpu = 0; 723 top = &group[0]; 724 packages = mp_ncpus / count; 725 top->cg_child = child = &group[1]; 726 top->cg_level = CG_SHARE_NONE; 727 for (i = 0; i < packages; i++, child++) 728 cpu = smp_topo_addleaf(top, child, share, count, flags, cpu); 729 return (top); 730 } 731 732 struct cpu_group * 733 smp_topo_2level(int l2share, int l2count, int l1share, int l1count, 734 int l1flags) 735 { 736 struct cpu_group *top; 737 struct cpu_group *l1g; 738 struct cpu_group *l2g; 739 int cpu; 740 int i; 741 int j; 742 743 cpu = 0; 744 top = &group[0]; 745 l2g = &group[1]; 746 top->cg_child = l2g; 747 top->cg_level = CG_SHARE_NONE; 748 top->cg_children = mp_ncpus / (l2count * l1count); 749 l1g = l2g + top->cg_children; 750 for (i = 0; i < top->cg_children; i++, l2g++) { 751 l2g->cg_parent = top; 752 l2g->cg_child = l1g; 753 l2g->cg_level = l2share; 754 for (j = 0; j < l2count; j++, l1g++) 755 cpu = smp_topo_addleaf(l2g, l1g, l1share, l1count, 756 l1flags, cpu); 757 } 758 return (top); 759 } 760 761 762 struct cpu_group * 763 smp_topo_find(struct cpu_group *top, int cpu) 764 { 765 struct cpu_group *cg; 766 cpuset_t mask; 767 int children; 768 int i; 769 770 CPU_SETOF(cpu, &mask); 771 cg = top; 772 for (;;) { 773 if (!CPU_OVERLAP(&cg->cg_mask, &mask)) 774 return (NULL); 775 if (cg->cg_children == 0) 776 return (cg); 777 children = cg->cg_children; 778 for (i = 0, cg = cg->cg_child; i < children; cg++, i++) 779 if (CPU_OVERLAP(&cg->cg_mask, &mask)) 780 break; 781 } 782 return (NULL); 783 } 784 #else /* !SMP */ 785 786 void 787 smp_rendezvous_cpus(cpuset_t map, 788 void (*setup_func)(void *), 789 void (*action_func)(void *), 790 void (*teardown_func)(void *), 791 void *arg) 792 { 793 /* 794 * In the !SMP case we just need to ensure the same initial conditions 795 * as the SMP case. 796 */ 797 spinlock_enter(); 798 if (setup_func != NULL) 799 setup_func(arg); 800 if (action_func != NULL) 801 action_func(arg); 802 if (teardown_func != NULL) 803 teardown_func(arg); 804 spinlock_exit(); 805 } 806 807 void 808 smp_rendezvous(void (*setup_func)(void *), 809 void (*action_func)(void *), 810 void (*teardown_func)(void *), 811 void *arg) 812 { 813 814 smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, 815 arg); 816 } 817 818 /* 819 * Provide dummy SMP support for UP kernels. Modules that need to use SMP 820 * APIs will still work using this dummy support. 821 */ 822 static void 823 mp_setvariables_for_up(void *dummy) 824 { 825 mp_ncpus = 1; 826 mp_maxid = PCPU_GET(cpuid); 827 CPU_SETOF(mp_maxid, &all_cpus); 828 KASSERT(PCPU_GET(cpuid) == 0, ("UP must have a CPU ID of zero")); 829 } 830 SYSINIT(cpu_mp_setvariables, SI_SUB_TUNABLES, SI_ORDER_FIRST, 831 mp_setvariables_for_up, NULL); 832 #endif /* SMP */ 833 834 void 835 smp_no_rendezvous_barrier(void *dummy) 836 { 837 #ifdef SMP 838 KASSERT((!smp_started),("smp_no_rendezvous called and smp is started")); 839 #endif 840 } 841 842 /* 843 * Wait for specified idle threads to switch once. This ensures that even 844 * preempted threads have cycled through the switch function once, 845 * exiting their codepaths. This allows us to change global pointers 846 * with no other synchronization. 847 */ 848 int 849 quiesce_cpus(cpuset_t map, const char *wmesg, int prio) 850 { 851 struct pcpu *pcpu; 852 u_int gen[MAXCPU]; 853 int error; 854 int cpu; 855 856 error = 0; 857 for (cpu = 0; cpu <= mp_maxid; cpu++) { 858 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 859 continue; 860 pcpu = pcpu_find(cpu); 861 gen[cpu] = pcpu->pc_idlethread->td_generation; 862 } 863 for (cpu = 0; cpu <= mp_maxid; cpu++) { 864 if (!CPU_ISSET(cpu, &map) || CPU_ABSENT(cpu)) 865 continue; 866 pcpu = pcpu_find(cpu); 867 thread_lock(curthread); 868 sched_bind(curthread, cpu); 869 thread_unlock(curthread); 870 while (gen[cpu] == pcpu->pc_idlethread->td_generation) { 871 error = tsleep(quiesce_cpus, prio, wmesg, 1); 872 if (error != EWOULDBLOCK) 873 goto out; 874 error = 0; 875 } 876 } 877 out: 878 thread_lock(curthread); 879 sched_unbind(curthread); 880 thread_unlock(curthread); 881 882 return (error); 883 } 884 885 int 886 quiesce_all_cpus(const char *wmesg, int prio) 887 { 888 889 return quiesce_cpus(all_cpus, wmesg, prio); 890 } 891 892 /* Extra care is taken with this sysctl because the data type is volatile */ 893 static int 894 sysctl_kern_smp_active(SYSCTL_HANDLER_ARGS) 895 { 896 int error, active; 897 898 active = smp_started; 899 error = SYSCTL_OUT(req, &active, sizeof(active)); 900 return (error); 901 } 902 903 904 #ifdef SMP 905 void 906 topo_init_node(struct topo_node *node) 907 { 908 909 bzero(node, sizeof(*node)); 910 TAILQ_INIT(&node->children); 911 } 912 913 void 914 topo_init_root(struct topo_node *root) 915 { 916 917 topo_init_node(root); 918 root->type = TOPO_TYPE_SYSTEM; 919 } 920 921 /* 922 * Add a child node with the given ID under the given parent. 923 * Do nothing if there is already a child with that ID. 924 */ 925 struct topo_node * 926 topo_add_node_by_hwid(struct topo_node *parent, int hwid, 927 topo_node_type type, uintptr_t subtype) 928 { 929 struct topo_node *node; 930 931 TAILQ_FOREACH_REVERSE(node, &parent->children, 932 topo_children, siblings) { 933 if (node->hwid == hwid 934 && node->type == type && node->subtype == subtype) { 935 return (node); 936 } 937 } 938 939 node = malloc(sizeof(*node), M_TOPO, M_WAITOK); 940 topo_init_node(node); 941 node->parent = parent; 942 node->hwid = hwid; 943 node->type = type; 944 node->subtype = subtype; 945 TAILQ_INSERT_TAIL(&parent->children, node, siblings); 946 parent->nchildren++; 947 948 return (node); 949 } 950 951 /* 952 * Find a child node with the given ID under the given parent. 953 */ 954 struct topo_node * 955 topo_find_node_by_hwid(struct topo_node *parent, int hwid, 956 topo_node_type type, uintptr_t subtype) 957 { 958 959 struct topo_node *node; 960 961 TAILQ_FOREACH(node, &parent->children, siblings) { 962 if (node->hwid == hwid 963 && node->type == type && node->subtype == subtype) { 964 return (node); 965 } 966 } 967 968 return (NULL); 969 } 970 971 /* 972 * Given a node change the order of its parent's child nodes such 973 * that the node becomes the firt child while preserving the cyclic 974 * order of the children. In other words, the given node is promoted 975 * by rotation. 976 */ 977 void 978 topo_promote_child(struct topo_node *child) 979 { 980 struct topo_node *next; 981 struct topo_node *node; 982 struct topo_node *parent; 983 984 parent = child->parent; 985 next = TAILQ_NEXT(child, siblings); 986 TAILQ_REMOVE(&parent->children, child, siblings); 987 TAILQ_INSERT_HEAD(&parent->children, child, siblings); 988 989 while (next != NULL) { 990 node = next; 991 next = TAILQ_NEXT(node, siblings); 992 TAILQ_REMOVE(&parent->children, node, siblings); 993 TAILQ_INSERT_AFTER(&parent->children, child, node, siblings); 994 child = node; 995 } 996 } 997 998 /* 999 * Iterate to the next node in the depth-first search (traversal) of 1000 * the topology tree. 1001 */ 1002 struct topo_node * 1003 topo_next_node(struct topo_node *top, struct topo_node *node) 1004 { 1005 struct topo_node *next; 1006 1007 if ((next = TAILQ_FIRST(&node->children)) != NULL) 1008 return (next); 1009 1010 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1011 return (next); 1012 1013 while (node != top && (node = node->parent) != top) 1014 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1015 return (next); 1016 1017 return (NULL); 1018 } 1019 1020 /* 1021 * Iterate to the next node in the depth-first search of the topology tree, 1022 * but without descending below the current node. 1023 */ 1024 struct topo_node * 1025 topo_next_nonchild_node(struct topo_node *top, struct topo_node *node) 1026 { 1027 struct topo_node *next; 1028 1029 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1030 return (next); 1031 1032 while (node != top && (node = node->parent) != top) 1033 if ((next = TAILQ_NEXT(node, siblings)) != NULL) 1034 return (next); 1035 1036 return (NULL); 1037 } 1038 1039 /* 1040 * Assign the given ID to the given topology node that represents a logical 1041 * processor. 1042 */ 1043 void 1044 topo_set_pu_id(struct topo_node *node, cpuid_t id) 1045 { 1046 1047 KASSERT(node->type == TOPO_TYPE_PU, 1048 ("topo_set_pu_id: wrong node type: %u", node->type)); 1049 KASSERT(CPU_EMPTY(&node->cpuset) && node->cpu_count == 0, 1050 ("topo_set_pu_id: cpuset already not empty")); 1051 node->id = id; 1052 CPU_SET(id, &node->cpuset); 1053 node->cpu_count = 1; 1054 node->subtype = 1; 1055 1056 while ((node = node->parent) != NULL) { 1057 KASSERT(!CPU_ISSET(id, &node->cpuset), 1058 ("logical ID %u is already set in node %p", id, node)); 1059 CPU_SET(id, &node->cpuset); 1060 node->cpu_count++; 1061 } 1062 } 1063 1064 static struct topology_spec { 1065 topo_node_type type; 1066 bool match_subtype; 1067 uintptr_t subtype; 1068 } topology_level_table[TOPO_LEVEL_COUNT] = { 1069 [TOPO_LEVEL_PKG] = { .type = TOPO_TYPE_PKG, }, 1070 [TOPO_LEVEL_GROUP] = { .type = TOPO_TYPE_GROUP, }, 1071 [TOPO_LEVEL_CACHEGROUP] = { 1072 .type = TOPO_TYPE_CACHE, 1073 .match_subtype = true, 1074 .subtype = CG_SHARE_L3, 1075 }, 1076 [TOPO_LEVEL_CORE] = { .type = TOPO_TYPE_CORE, }, 1077 [TOPO_LEVEL_THREAD] = { .type = TOPO_TYPE_PU, }, 1078 }; 1079 1080 static bool 1081 topo_analyze_table(struct topo_node *root, int all, enum topo_level level, 1082 struct topo_analysis *results) 1083 { 1084 struct topology_spec *spec; 1085 struct topo_node *node; 1086 int count; 1087 1088 if (level >= TOPO_LEVEL_COUNT) 1089 return (true); 1090 1091 spec = &topology_level_table[level]; 1092 count = 0; 1093 node = topo_next_node(root, root); 1094 1095 while (node != NULL) { 1096 if (node->type != spec->type || 1097 (spec->match_subtype && node->subtype != spec->subtype)) { 1098 node = topo_next_node(root, node); 1099 continue; 1100 } 1101 if (!all && CPU_EMPTY(&node->cpuset)) { 1102 node = topo_next_nonchild_node(root, node); 1103 continue; 1104 } 1105 1106 count++; 1107 1108 if (!topo_analyze_table(node, all, level + 1, results)) 1109 return (false); 1110 1111 node = topo_next_nonchild_node(root, node); 1112 } 1113 1114 /* No explicit subgroups is essentially one subgroup. */ 1115 if (count == 0) { 1116 count = 1; 1117 1118 if (!topo_analyze_table(root, all, level + 1, results)) 1119 return (false); 1120 } 1121 1122 if (results->entities[level] == -1) 1123 results->entities[level] = count; 1124 else if (results->entities[level] != count) 1125 return (false); 1126 1127 return (true); 1128 } 1129 1130 /* 1131 * Check if the topology is uniform, that is, each package has the same number 1132 * of cores in it and each core has the same number of threads (logical 1133 * processors) in it. If so, calculate the number of packages, the number of 1134 * groups per package, the number of cachegroups per group, and the number of 1135 * logical processors per cachegroup. 'all' parameter tells whether to include 1136 * administratively disabled logical processors into the analysis. 1137 */ 1138 int 1139 topo_analyze(struct topo_node *topo_root, int all, 1140 struct topo_analysis *results) 1141 { 1142 1143 results->entities[TOPO_LEVEL_PKG] = -1; 1144 results->entities[TOPO_LEVEL_CORE] = -1; 1145 results->entities[TOPO_LEVEL_THREAD] = -1; 1146 results->entities[TOPO_LEVEL_GROUP] = -1; 1147 results->entities[TOPO_LEVEL_CACHEGROUP] = -1; 1148 1149 if (!topo_analyze_table(topo_root, all, TOPO_LEVEL_PKG, results)) 1150 return (0); 1151 1152 KASSERT(results->entities[TOPO_LEVEL_PKG] > 0, 1153 ("bug in topology or analysis")); 1154 1155 return (1); 1156 } 1157 1158 #endif /* SMP */ 1159 1160