1 /* 2 * SMP support for ppc. 3 * 4 * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great 5 * deal of code from the sparc and intel versions. 6 * 7 * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu> 8 * 9 * PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and 10 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 */ 17 18 #undef DEBUG 19 20 #include <linux/kernel.h> 21 #include <linux/module.h> 22 #include <linux/sched.h> 23 #include <linux/smp.h> 24 #include <linux/interrupt.h> 25 #include <linux/delay.h> 26 #include <linux/init.h> 27 #include <linux/spinlock.h> 28 #include <linux/cache.h> 29 #include <linux/err.h> 30 #include <linux/sysdev.h> 31 #include <linux/cpu.h> 32 #include <linux/notifier.h> 33 #include <linux/topology.h> 34 35 #include <asm/ptrace.h> 36 #include <asm/atomic.h> 37 #include <asm/irq.h> 38 #include <asm/page.h> 39 #include <asm/pgtable.h> 40 #include <asm/prom.h> 41 #include <asm/smp.h> 42 #include <asm/time.h> 43 #include <asm/machdep.h> 44 #include <asm/cputhreads.h> 45 #include <asm/cputable.h> 46 #include <asm/system.h> 47 #include <asm/mpic.h> 48 #include <asm/vdso_datapage.h> 49 #ifdef CONFIG_PPC64 50 #include <asm/paca.h> 51 #endif 52 53 #ifdef DEBUG 54 #include <asm/udbg.h> 55 #define DBG(fmt...) udbg_printf(fmt) 56 #else 57 #define DBG(fmt...) 58 #endif 59 60 61 /* Store all idle threads, this can be reused instead of creating 62 * a new thread. Also avoids complicated thread destroy functionality 63 * for idle threads. 64 */ 65 #ifdef CONFIG_HOTPLUG_CPU 66 /* 67 * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is 68 * removed after init for !CONFIG_HOTPLUG_CPU. 69 */ 70 static DEFINE_PER_CPU(struct task_struct *, idle_thread_array); 71 #define get_idle_for_cpu(x) (per_cpu(idle_thread_array, x)) 72 #define set_idle_for_cpu(x, p) (per_cpu(idle_thread_array, x) = (p)) 73 #else 74 static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ; 75 #define get_idle_for_cpu(x) (idle_thread_array[(x)]) 76 #define set_idle_for_cpu(x, p) (idle_thread_array[(x)] = (p)) 77 #endif 78 79 struct thread_info *secondary_ti; 80 81 DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map); 82 DEFINE_PER_CPU(cpumask_var_t, cpu_core_map); 83 84 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map); 85 EXPORT_PER_CPU_SYMBOL(cpu_core_map); 86 87 /* SMP operations for this machine */ 88 struct smp_ops_t *smp_ops; 89 90 /* Can't be static due to PowerMac hackery */ 91 volatile unsigned int cpu_callin_map[NR_CPUS]; 92 93 int smt_enabled_at_boot = 1; 94 95 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL; 96 97 #ifdef CONFIG_PPC64 98 void __devinit smp_generic_kick_cpu(int nr) 99 { 100 BUG_ON(nr < 0 || nr >= NR_CPUS); 101 102 /* 103 * The processor is currently spinning, waiting for the 104 * cpu_start field to become non-zero After we set cpu_start, 105 * the processor will continue on to secondary_start 106 */ 107 paca[nr].cpu_start = 1; 108 smp_mb(); 109 } 110 #endif 111 112 void smp_message_recv(int msg) 113 { 114 switch(msg) { 115 case PPC_MSG_CALL_FUNCTION: 116 generic_smp_call_function_interrupt(); 117 break; 118 case PPC_MSG_RESCHEDULE: 119 /* we notice need_resched on exit */ 120 break; 121 case PPC_MSG_CALL_FUNC_SINGLE: 122 generic_smp_call_function_single_interrupt(); 123 break; 124 case PPC_MSG_DEBUGGER_BREAK: 125 if (crash_ipi_function_ptr) { 126 crash_ipi_function_ptr(get_irq_regs()); 127 break; 128 } 129 #ifdef CONFIG_DEBUGGER 130 debugger_ipi(get_irq_regs()); 131 break; 132 #endif /* CONFIG_DEBUGGER */ 133 /* FALLTHROUGH */ 134 default: 135 printk("SMP %d: smp_message_recv(): unknown msg %d\n", 136 smp_processor_id(), msg); 137 break; 138 } 139 } 140 141 static irqreturn_t call_function_action(int irq, void *data) 142 { 143 generic_smp_call_function_interrupt(); 144 return IRQ_HANDLED; 145 } 146 147 static irqreturn_t reschedule_action(int irq, void *data) 148 { 149 /* we just need the return path side effect of checking need_resched */ 150 return IRQ_HANDLED; 151 } 152 153 static irqreturn_t call_function_single_action(int irq, void *data) 154 { 155 generic_smp_call_function_single_interrupt(); 156 return IRQ_HANDLED; 157 } 158 159 static irqreturn_t debug_ipi_action(int irq, void *data) 160 { 161 smp_message_recv(PPC_MSG_DEBUGGER_BREAK); 162 return IRQ_HANDLED; 163 } 164 165 static irq_handler_t smp_ipi_action[] = { 166 [PPC_MSG_CALL_FUNCTION] = call_function_action, 167 [PPC_MSG_RESCHEDULE] = reschedule_action, 168 [PPC_MSG_CALL_FUNC_SINGLE] = call_function_single_action, 169 [PPC_MSG_DEBUGGER_BREAK] = debug_ipi_action, 170 }; 171 172 const char *smp_ipi_name[] = { 173 [PPC_MSG_CALL_FUNCTION] = "ipi call function", 174 [PPC_MSG_RESCHEDULE] = "ipi reschedule", 175 [PPC_MSG_CALL_FUNC_SINGLE] = "ipi call function single", 176 [PPC_MSG_DEBUGGER_BREAK] = "ipi debugger", 177 }; 178 179 /* optional function to request ipi, for controllers with >= 4 ipis */ 180 int smp_request_message_ipi(int virq, int msg) 181 { 182 int err; 183 184 if (msg < 0 || msg > PPC_MSG_DEBUGGER_BREAK) { 185 return -EINVAL; 186 } 187 #if !defined(CONFIG_DEBUGGER) && !defined(CONFIG_KEXEC) 188 if (msg == PPC_MSG_DEBUGGER_BREAK) { 189 return 1; 190 } 191 #endif 192 err = request_irq(virq, smp_ipi_action[msg], IRQF_DISABLED|IRQF_PERCPU, 193 smp_ipi_name[msg], 0); 194 WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n", 195 virq, smp_ipi_name[msg], err); 196 197 return err; 198 } 199 200 void smp_send_reschedule(int cpu) 201 { 202 if (likely(smp_ops)) 203 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE); 204 } 205 206 void arch_send_call_function_single_ipi(int cpu) 207 { 208 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE); 209 } 210 211 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 212 { 213 unsigned int cpu; 214 215 for_each_cpu(cpu, mask) 216 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION); 217 } 218 219 #ifdef CONFIG_DEBUGGER 220 void smp_send_debugger_break(int cpu) 221 { 222 if (likely(smp_ops)) 223 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK); 224 } 225 #endif 226 227 #ifdef CONFIG_KEXEC 228 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) 229 { 230 crash_ipi_function_ptr = crash_ipi_callback; 231 if (crash_ipi_callback && smp_ops) { 232 mb(); 233 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK); 234 } 235 } 236 #endif 237 238 static void stop_this_cpu(void *dummy) 239 { 240 /* Remove this CPU */ 241 set_cpu_online(smp_processor_id(), false); 242 243 local_irq_disable(); 244 while (1) 245 ; 246 } 247 248 void smp_send_stop(void) 249 { 250 smp_call_function(stop_this_cpu, NULL, 0); 251 } 252 253 struct thread_info *current_set[NR_CPUS]; 254 255 static void __devinit smp_store_cpu_info(int id) 256 { 257 per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR); 258 } 259 260 void __init smp_prepare_cpus(unsigned int max_cpus) 261 { 262 unsigned int cpu; 263 264 DBG("smp_prepare_cpus\n"); 265 266 /* 267 * setup_cpu may need to be called on the boot cpu. We havent 268 * spun any cpus up but lets be paranoid. 269 */ 270 BUG_ON(boot_cpuid != smp_processor_id()); 271 272 /* Fixup boot cpu */ 273 smp_store_cpu_info(boot_cpuid); 274 cpu_callin_map[boot_cpuid] = 1; 275 276 for_each_possible_cpu(cpu) { 277 zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu), 278 GFP_KERNEL, cpu_to_node(cpu)); 279 zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu), 280 GFP_KERNEL, cpu_to_node(cpu)); 281 } 282 283 cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid)); 284 cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid)); 285 286 if (smp_ops) 287 if (smp_ops->probe) 288 max_cpus = smp_ops->probe(); 289 else 290 max_cpus = NR_CPUS; 291 else 292 max_cpus = 1; 293 } 294 295 void __devinit smp_prepare_boot_cpu(void) 296 { 297 BUG_ON(smp_processor_id() != boot_cpuid); 298 #ifdef CONFIG_PPC64 299 paca[boot_cpuid].__current = current; 300 #endif 301 current_set[boot_cpuid] = task_thread_info(current); 302 } 303 304 #ifdef CONFIG_HOTPLUG_CPU 305 /* State of each CPU during hotplug phases */ 306 static DEFINE_PER_CPU(int, cpu_state) = { 0 }; 307 308 int generic_cpu_disable(void) 309 { 310 unsigned int cpu = smp_processor_id(); 311 312 if (cpu == boot_cpuid) 313 return -EBUSY; 314 315 set_cpu_online(cpu, false); 316 #ifdef CONFIG_PPC64 317 vdso_data->processorCount--; 318 #endif 319 migrate_irqs(); 320 return 0; 321 } 322 323 void generic_cpu_die(unsigned int cpu) 324 { 325 int i; 326 327 for (i = 0; i < 100; i++) { 328 smp_rmb(); 329 if (per_cpu(cpu_state, cpu) == CPU_DEAD) 330 return; 331 msleep(100); 332 } 333 printk(KERN_ERR "CPU%d didn't die...\n", cpu); 334 } 335 336 void generic_mach_cpu_die(void) 337 { 338 unsigned int cpu; 339 340 local_irq_disable(); 341 idle_task_exit(); 342 cpu = smp_processor_id(); 343 printk(KERN_DEBUG "CPU%d offline\n", cpu); 344 __get_cpu_var(cpu_state) = CPU_DEAD; 345 smp_wmb(); 346 while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE) 347 cpu_relax(); 348 } 349 350 void generic_set_cpu_dead(unsigned int cpu) 351 { 352 per_cpu(cpu_state, cpu) = CPU_DEAD; 353 } 354 #endif 355 356 struct create_idle { 357 struct work_struct work; 358 struct task_struct *idle; 359 struct completion done; 360 int cpu; 361 }; 362 363 static void __cpuinit do_fork_idle(struct work_struct *work) 364 { 365 struct create_idle *c_idle = 366 container_of(work, struct create_idle, work); 367 368 c_idle->idle = fork_idle(c_idle->cpu); 369 complete(&c_idle->done); 370 } 371 372 static int __cpuinit create_idle(unsigned int cpu) 373 { 374 struct thread_info *ti; 375 struct create_idle c_idle = { 376 .cpu = cpu, 377 .done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done), 378 }; 379 INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle); 380 381 c_idle.idle = get_idle_for_cpu(cpu); 382 383 /* We can't use kernel_thread since we must avoid to 384 * reschedule the child. We use a workqueue because 385 * we want to fork from a kernel thread, not whatever 386 * userspace process happens to be trying to online us. 387 */ 388 if (!c_idle.idle) { 389 schedule_work(&c_idle.work); 390 wait_for_completion(&c_idle.done); 391 } else 392 init_idle(c_idle.idle, cpu); 393 if (IS_ERR(c_idle.idle)) { 394 pr_err("Failed fork for CPU %u: %li", cpu, PTR_ERR(c_idle.idle)); 395 return PTR_ERR(c_idle.idle); 396 } 397 ti = task_thread_info(c_idle.idle); 398 399 #ifdef CONFIG_PPC64 400 paca[cpu].__current = c_idle.idle; 401 paca[cpu].kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD; 402 #endif 403 ti->cpu = cpu; 404 current_set[cpu] = ti; 405 406 return 0; 407 } 408 409 int __cpuinit __cpu_up(unsigned int cpu) 410 { 411 int rc, c; 412 413 secondary_ti = current_set[cpu]; 414 415 if (smp_ops == NULL || 416 (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu))) 417 return -EINVAL; 418 419 /* Make sure we have an idle thread */ 420 rc = create_idle(cpu); 421 if (rc) 422 return rc; 423 424 /* Make sure callin-map entry is 0 (can be leftover a CPU 425 * hotplug 426 */ 427 cpu_callin_map[cpu] = 0; 428 429 /* The information for processor bringup must 430 * be written out to main store before we release 431 * the processor. 432 */ 433 smp_mb(); 434 435 /* wake up cpus */ 436 DBG("smp: kicking cpu %d\n", cpu); 437 smp_ops->kick_cpu(cpu); 438 439 /* 440 * wait to see if the cpu made a callin (is actually up). 441 * use this value that I found through experimentation. 442 * -- Cort 443 */ 444 if (system_state < SYSTEM_RUNNING) 445 for (c = 50000; c && !cpu_callin_map[cpu]; c--) 446 udelay(100); 447 #ifdef CONFIG_HOTPLUG_CPU 448 else 449 /* 450 * CPUs can take much longer to come up in the 451 * hotplug case. Wait five seconds. 452 */ 453 for (c = 5000; c && !cpu_callin_map[cpu]; c--) 454 msleep(1); 455 #endif 456 457 if (!cpu_callin_map[cpu]) { 458 printk(KERN_ERR "Processor %u is stuck.\n", cpu); 459 return -ENOENT; 460 } 461 462 DBG("Processor %u found.\n", cpu); 463 464 if (smp_ops->give_timebase) 465 smp_ops->give_timebase(); 466 467 /* Wait until cpu puts itself in the online map */ 468 while (!cpu_online(cpu)) 469 cpu_relax(); 470 471 return 0; 472 } 473 474 /* Return the value of the reg property corresponding to the given 475 * logical cpu. 476 */ 477 int cpu_to_core_id(int cpu) 478 { 479 struct device_node *np; 480 const int *reg; 481 int id = -1; 482 483 np = of_get_cpu_node(cpu, NULL); 484 if (!np) 485 goto out; 486 487 reg = of_get_property(np, "reg", NULL); 488 if (!reg) 489 goto out; 490 491 id = *reg; 492 out: 493 of_node_put(np); 494 return id; 495 } 496 497 /* Helper routines for cpu to core mapping */ 498 int cpu_core_index_of_thread(int cpu) 499 { 500 return cpu >> threads_shift; 501 } 502 EXPORT_SYMBOL_GPL(cpu_core_index_of_thread); 503 504 int cpu_first_thread_of_core(int core) 505 { 506 return core << threads_shift; 507 } 508 EXPORT_SYMBOL_GPL(cpu_first_thread_of_core); 509 510 /* Must be called when no change can occur to cpu_present_map, 511 * i.e. during cpu online or offline. 512 */ 513 static struct device_node *cpu_to_l2cache(int cpu) 514 { 515 struct device_node *np; 516 struct device_node *cache; 517 518 if (!cpu_present(cpu)) 519 return NULL; 520 521 np = of_get_cpu_node(cpu, NULL); 522 if (np == NULL) 523 return NULL; 524 525 cache = of_find_next_cache_node(np); 526 527 of_node_put(np); 528 529 return cache; 530 } 531 532 /* Activate a secondary processor. */ 533 void __devinit start_secondary(void *unused) 534 { 535 unsigned int cpu = smp_processor_id(); 536 struct device_node *l2_cache; 537 int i, base; 538 539 atomic_inc(&init_mm.mm_count); 540 current->active_mm = &init_mm; 541 542 smp_store_cpu_info(cpu); 543 set_dec(tb_ticks_per_jiffy); 544 preempt_disable(); 545 cpu_callin_map[cpu] = 1; 546 547 if (smp_ops->setup_cpu) 548 smp_ops->setup_cpu(cpu); 549 if (smp_ops->take_timebase) 550 smp_ops->take_timebase(); 551 552 secondary_cpu_time_init(); 553 554 #ifdef CONFIG_PPC64 555 if (system_state == SYSTEM_RUNNING) 556 vdso_data->processorCount++; 557 #endif 558 ipi_call_lock(); 559 notify_cpu_starting(cpu); 560 set_cpu_online(cpu, true); 561 /* Update sibling maps */ 562 base = cpu_first_thread_sibling(cpu); 563 for (i = 0; i < threads_per_core; i++) { 564 if (cpu_is_offline(base + i)) 565 continue; 566 cpumask_set_cpu(cpu, cpu_sibling_mask(base + i)); 567 cpumask_set_cpu(base + i, cpu_sibling_mask(cpu)); 568 569 /* cpu_core_map should be a superset of 570 * cpu_sibling_map even if we don't have cache 571 * information, so update the former here, too. 572 */ 573 cpumask_set_cpu(cpu, cpu_core_mask(base + i)); 574 cpumask_set_cpu(base + i, cpu_core_mask(cpu)); 575 } 576 l2_cache = cpu_to_l2cache(cpu); 577 for_each_online_cpu(i) { 578 struct device_node *np = cpu_to_l2cache(i); 579 if (!np) 580 continue; 581 if (np == l2_cache) { 582 cpumask_set_cpu(cpu, cpu_core_mask(i)); 583 cpumask_set_cpu(i, cpu_core_mask(cpu)); 584 } 585 of_node_put(np); 586 } 587 of_node_put(l2_cache); 588 ipi_call_unlock(); 589 590 local_irq_enable(); 591 592 cpu_idle(); 593 594 BUG(); 595 } 596 597 int setup_profiling_timer(unsigned int multiplier) 598 { 599 return 0; 600 } 601 602 void __init smp_cpus_done(unsigned int max_cpus) 603 { 604 cpumask_var_t old_mask; 605 606 /* We want the setup_cpu() here to be called from CPU 0, but our 607 * init thread may have been "borrowed" by another CPU in the meantime 608 * se we pin us down to CPU 0 for a short while 609 */ 610 alloc_cpumask_var(&old_mask, GFP_NOWAIT); 611 cpumask_copy(old_mask, ¤t->cpus_allowed); 612 set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid)); 613 614 if (smp_ops && smp_ops->setup_cpu) 615 smp_ops->setup_cpu(boot_cpuid); 616 617 set_cpus_allowed_ptr(current, old_mask); 618 619 free_cpumask_var(old_mask); 620 621 if (smp_ops && smp_ops->bringup_done) 622 smp_ops->bringup_done(); 623 624 dump_numa_cpu_topology(); 625 626 } 627 628 int arch_sd_sibling_asym_packing(void) 629 { 630 if (cpu_has_feature(CPU_FTR_ASYM_SMT)) { 631 printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n"); 632 return SD_ASYM_PACKING; 633 } 634 return 0; 635 } 636 637 #ifdef CONFIG_HOTPLUG_CPU 638 int __cpu_disable(void) 639 { 640 struct device_node *l2_cache; 641 int cpu = smp_processor_id(); 642 int base, i; 643 int err; 644 645 if (!smp_ops->cpu_disable) 646 return -ENOSYS; 647 648 err = smp_ops->cpu_disable(); 649 if (err) 650 return err; 651 652 /* Update sibling maps */ 653 base = cpu_first_thread_sibling(cpu); 654 for (i = 0; i < threads_per_core; i++) { 655 cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i)); 656 cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu)); 657 cpumask_clear_cpu(cpu, cpu_core_mask(base + i)); 658 cpumask_clear_cpu(base + i, cpu_core_mask(cpu)); 659 } 660 661 l2_cache = cpu_to_l2cache(cpu); 662 for_each_present_cpu(i) { 663 struct device_node *np = cpu_to_l2cache(i); 664 if (!np) 665 continue; 666 if (np == l2_cache) { 667 cpumask_clear_cpu(cpu, cpu_core_mask(i)); 668 cpumask_clear_cpu(i, cpu_core_mask(cpu)); 669 } 670 of_node_put(np); 671 } 672 of_node_put(l2_cache); 673 674 675 return 0; 676 } 677 678 void __cpu_die(unsigned int cpu) 679 { 680 if (smp_ops->cpu_die) 681 smp_ops->cpu_die(cpu); 682 } 683 684 static DEFINE_MUTEX(powerpc_cpu_hotplug_driver_mutex); 685 686 void cpu_hotplug_driver_lock() 687 { 688 mutex_lock(&powerpc_cpu_hotplug_driver_mutex); 689 } 690 691 void cpu_hotplug_driver_unlock() 692 { 693 mutex_unlock(&powerpc_cpu_hotplug_driver_mutex); 694 } 695 696 void cpu_die(void) 697 { 698 if (ppc_md.cpu_die) 699 ppc_md.cpu_die(); 700 701 /* If we return, we re-enter start_secondary */ 702 start_secondary_resume(); 703 } 704 705 #endif 706