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