1/* 2 * linux/arch/arm/kernel/smp.c 3 * 4 * Copyright (C) 2002 ARM Limited, All Rights Reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10#include <linux/module.h> 11#include <linux/delay.h> 12#include <linux/init.h> 13#include <linux/spinlock.h> 14#include <linux/sched.h> 15#include <linux/interrupt.h> 16#include <linux/cache.h> 17#include <linux/profile.h> 18#include <linux/errno.h> 19#include <linux/mm.h> 20#include <linux/err.h> 21#include <linux/cpu.h> 22#include <linux/seq_file.h> 23#include <linux/irq.h> 24#include <linux/percpu.h> 25#include <linux/clockchips.h> 26#include <linux/completion.h> 27#include <linux/cpufreq.h> 28#include <linux/irq_work.h> 29 30#include <linux/atomic.h> 31#include <asm/smp.h> 32#include <asm/cacheflush.h> 33#include <asm/cpu.h> 34#include <asm/cputype.h> 35#include <asm/exception.h> 36#include <asm/idmap.h> 37#include <asm/topology.h> 38#include <asm/mmu_context.h> 39#include <asm/pgtable.h> 40#include <asm/pgalloc.h> 41#include <asm/processor.h> 42#include <asm/sections.h> 43#include <asm/tlbflush.h> 44#include <asm/ptrace.h> 45#include <asm/smp_plat.h> 46#include <asm/virt.h> 47#include <asm/mach/arch.h> 48#include <asm/mpu.h> 49 50#define CREATE_TRACE_POINTS 51#include <trace/events/ipi.h> 52 53/* 54 * as from 2.5, kernels no longer have an init_tasks structure 55 * so we need some other way of telling a new secondary core 56 * where to place its SVC stack 57 */ 58struct secondary_data secondary_data; 59 60/* 61 * control for which core is the next to come out of the secondary 62 * boot "holding pen" 63 */ 64volatile int pen_release = -1; 65 66enum ipi_msg_type { 67 IPI_WAKEUP, 68 IPI_TIMER, 69 IPI_RESCHEDULE, 70 IPI_CALL_FUNC, 71 IPI_CALL_FUNC_SINGLE, 72 IPI_CPU_STOP, 73 IPI_IRQ_WORK, 74 IPI_COMPLETION, 75}; 76 77static DECLARE_COMPLETION(cpu_running); 78 79static struct smp_operations smp_ops; 80 81void __init smp_set_ops(struct smp_operations *ops) 82{ 83 if (ops) 84 smp_ops = *ops; 85}; 86 87static unsigned long get_arch_pgd(pgd_t *pgd) 88{ 89 phys_addr_t pgdir = virt_to_idmap(pgd); 90 BUG_ON(pgdir & ARCH_PGD_MASK); 91 return pgdir >> ARCH_PGD_SHIFT; 92} 93 94int __cpu_up(unsigned int cpu, struct task_struct *idle) 95{ 96 int ret; 97 98 if (!smp_ops.smp_boot_secondary) 99 return -ENOSYS; 100 101 /* 102 * We need to tell the secondary core where to find 103 * its stack and the page tables. 104 */ 105 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP; 106#ifdef CONFIG_ARM_MPU 107 secondary_data.mpu_rgn_szr = mpu_rgn_info.rgns[MPU_RAM_REGION].drsr; 108#endif 109 110#ifdef CONFIG_MMU 111 secondary_data.pgdir = get_arch_pgd(idmap_pgd); 112 secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir); 113#endif 114 sync_cache_w(&secondary_data); 115 116 /* 117 * Now bring the CPU into our world. 118 */ 119 ret = smp_ops.smp_boot_secondary(cpu, idle); 120 if (ret == 0) { 121 /* 122 * CPU was successfully started, wait for it 123 * to come online or time out. 124 */ 125 wait_for_completion_timeout(&cpu_running, 126 msecs_to_jiffies(1000)); 127 128 if (!cpu_online(cpu)) { 129 pr_crit("CPU%u: failed to come online\n", cpu); 130 ret = -EIO; 131 } 132 } else { 133 pr_err("CPU%u: failed to boot: %d\n", cpu, ret); 134 } 135 136 137 memset(&secondary_data, 0, sizeof(secondary_data)); 138 return ret; 139} 140 141/* platform specific SMP operations */ 142void __init smp_init_cpus(void) 143{ 144 if (smp_ops.smp_init_cpus) 145 smp_ops.smp_init_cpus(); 146} 147 148int platform_can_secondary_boot(void) 149{ 150 return !!smp_ops.smp_boot_secondary; 151} 152 153int platform_can_cpu_hotplug(void) 154{ 155#ifdef CONFIG_HOTPLUG_CPU 156 if (smp_ops.cpu_kill) 157 return 1; 158#endif 159 160 return 0; 161} 162 163#ifdef CONFIG_HOTPLUG_CPU 164static int platform_cpu_kill(unsigned int cpu) 165{ 166 if (smp_ops.cpu_kill) 167 return smp_ops.cpu_kill(cpu); 168 return 1; 169} 170 171static int platform_cpu_disable(unsigned int cpu) 172{ 173 if (smp_ops.cpu_disable) 174 return smp_ops.cpu_disable(cpu); 175 176 /* 177 * By default, allow disabling all CPUs except the first one, 178 * since this is special on a lot of platforms, e.g. because 179 * of clock tick interrupts. 180 */ 181 return cpu == 0 ? -EPERM : 0; 182} 183/* 184 * __cpu_disable runs on the processor to be shutdown. 185 */ 186int __cpu_disable(void) 187{ 188 unsigned int cpu = smp_processor_id(); 189 int ret; 190 191 ret = platform_cpu_disable(cpu); 192 if (ret) 193 return ret; 194 195 /* 196 * Take this CPU offline. Once we clear this, we can't return, 197 * and we must not schedule until we're ready to give up the cpu. 198 */ 199 set_cpu_online(cpu, false); 200 201 /* 202 * OK - migrate IRQs away from this CPU 203 */ 204 migrate_irqs(); 205 206 /* 207 * Flush user cache and TLB mappings, and then remove this CPU 208 * from the vm mask set of all processes. 209 * 210 * Caches are flushed to the Level of Unification Inner Shareable 211 * to write-back dirty lines to unified caches shared by all CPUs. 212 */ 213 flush_cache_louis(); 214 local_flush_tlb_all(); 215 216 clear_tasks_mm_cpumask(cpu); 217 218 return 0; 219} 220 221static DECLARE_COMPLETION(cpu_died); 222 223/* 224 * called on the thread which is asking for a CPU to be shutdown - 225 * waits until shutdown has completed, or it is timed out. 226 */ 227void __cpu_die(unsigned int cpu) 228{ 229 if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) { 230 pr_err("CPU%u: cpu didn't die\n", cpu); 231 return; 232 } 233 pr_notice("CPU%u: shutdown\n", cpu); 234 235 /* 236 * platform_cpu_kill() is generally expected to do the powering off 237 * and/or cutting of clocks to the dying CPU. Optionally, this may 238 * be done by the CPU which is dying in preference to supporting 239 * this call, but that means there is _no_ synchronisation between 240 * the requesting CPU and the dying CPU actually losing power. 241 */ 242 if (!platform_cpu_kill(cpu)) 243 pr_err("CPU%u: unable to kill\n", cpu); 244} 245 246/* 247 * Called from the idle thread for the CPU which has been shutdown. 248 * 249 * Note that we disable IRQs here, but do not re-enable them 250 * before returning to the caller. This is also the behaviour 251 * of the other hotplug-cpu capable cores, so presumably coming 252 * out of idle fixes this. 253 */ 254void __ref cpu_die(void) 255{ 256 unsigned int cpu = smp_processor_id(); 257 258 idle_task_exit(); 259 260 local_irq_disable(); 261 262 /* 263 * Flush the data out of the L1 cache for this CPU. This must be 264 * before the completion to ensure that data is safely written out 265 * before platform_cpu_kill() gets called - which may disable 266 * *this* CPU and power down its cache. 267 */ 268 flush_cache_louis(); 269 270 /* 271 * Tell __cpu_die() that this CPU is now safe to dispose of. Once 272 * this returns, power and/or clocks can be removed at any point 273 * from this CPU and its cache by platform_cpu_kill(). 274 */ 275 complete(&cpu_died); 276 277 /* 278 * Ensure that the cache lines associated with that completion are 279 * written out. This covers the case where _this_ CPU is doing the 280 * powering down, to ensure that the completion is visible to the 281 * CPU waiting for this one. 282 */ 283 flush_cache_louis(); 284 285 /* 286 * The actual CPU shutdown procedure is at least platform (if not 287 * CPU) specific. This may remove power, or it may simply spin. 288 * 289 * Platforms are generally expected *NOT* to return from this call, 290 * although there are some which do because they have no way to 291 * power down the CPU. These platforms are the _only_ reason we 292 * have a return path which uses the fragment of assembly below. 293 * 294 * The return path should not be used for platforms which can 295 * power off the CPU. 296 */ 297 if (smp_ops.cpu_die) 298 smp_ops.cpu_die(cpu); 299 300 pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n", 301 cpu); 302 303 /* 304 * Do not return to the idle loop - jump back to the secondary 305 * cpu initialisation. There's some initialisation which needs 306 * to be repeated to undo the effects of taking the CPU offline. 307 */ 308 __asm__("mov sp, %0\n" 309 " mov fp, #0\n" 310 " b secondary_start_kernel" 311 : 312 : "r" (task_stack_page(current) + THREAD_SIZE - 8)); 313} 314#endif /* CONFIG_HOTPLUG_CPU */ 315 316/* 317 * Called by both boot and secondaries to move global data into 318 * per-processor storage. 319 */ 320static void smp_store_cpu_info(unsigned int cpuid) 321{ 322 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid); 323 324 cpu_info->loops_per_jiffy = loops_per_jiffy; 325 cpu_info->cpuid = read_cpuid_id(); 326 327 store_cpu_topology(cpuid); 328} 329 330/* 331 * This is the secondary CPU boot entry. We're using this CPUs 332 * idle thread stack, but a set of temporary page tables. 333 */ 334asmlinkage void secondary_start_kernel(void) 335{ 336 struct mm_struct *mm = &init_mm; 337 unsigned int cpu; 338 339 /* 340 * The identity mapping is uncached (strongly ordered), so 341 * switch away from it before attempting any exclusive accesses. 342 */ 343 cpu_switch_mm(mm->pgd, mm); 344 local_flush_bp_all(); 345 enter_lazy_tlb(mm, current); 346 local_flush_tlb_all(); 347 348 /* 349 * All kernel threads share the same mm context; grab a 350 * reference and switch to it. 351 */ 352 cpu = smp_processor_id(); 353 atomic_inc(&mm->mm_count); 354 current->active_mm = mm; 355 cpumask_set_cpu(cpu, mm_cpumask(mm)); 356 357 cpu_init(); 358 359 pr_debug("CPU%u: Booted secondary processor\n", cpu); 360 361 preempt_disable(); 362 trace_hardirqs_off(); 363 364 /* 365 * Give the platform a chance to do its own initialisation. 366 */ 367 if (smp_ops.smp_secondary_init) 368 smp_ops.smp_secondary_init(cpu); 369 370 notify_cpu_starting(cpu); 371 372 calibrate_delay(); 373 374 smp_store_cpu_info(cpu); 375 376 /* 377 * OK, now it's safe to let the boot CPU continue. Wait for 378 * the CPU migration code to notice that the CPU is online 379 * before we continue - which happens after __cpu_up returns. 380 */ 381 set_cpu_online(cpu, true); 382 complete(&cpu_running); 383 384 local_irq_enable(); 385 local_fiq_enable(); 386 387 /* 388 * OK, it's off to the idle thread for us 389 */ 390 cpu_startup_entry(CPUHP_ONLINE); 391} 392 393void __init smp_cpus_done(unsigned int max_cpus) 394{ 395 int cpu; 396 unsigned long bogosum = 0; 397 398 for_each_online_cpu(cpu) 399 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy; 400 401 printk(KERN_INFO "SMP: Total of %d processors activated " 402 "(%lu.%02lu BogoMIPS).\n", 403 num_online_cpus(), 404 bogosum / (500000/HZ), 405 (bogosum / (5000/HZ)) % 100); 406 407 hyp_mode_check(); 408} 409 410void __init smp_prepare_boot_cpu(void) 411{ 412 set_my_cpu_offset(per_cpu_offset(smp_processor_id())); 413} 414 415void __init smp_prepare_cpus(unsigned int max_cpus) 416{ 417 unsigned int ncores = num_possible_cpus(); 418 419 init_cpu_topology(); 420 421 smp_store_cpu_info(smp_processor_id()); 422 423 /* 424 * are we trying to boot more cores than exist? 425 */ 426 if (max_cpus > ncores) 427 max_cpus = ncores; 428 if (ncores > 1 && max_cpus) { 429 /* 430 * Initialise the present map, which describes the set of CPUs 431 * actually populated at the present time. A platform should 432 * re-initialize the map in the platforms smp_prepare_cpus() 433 * if present != possible (e.g. physical hotplug). 434 */ 435 init_cpu_present(cpu_possible_mask); 436 437 /* 438 * Initialise the SCU if there are more than one CPU 439 * and let them know where to start. 440 */ 441 if (smp_ops.smp_prepare_cpus) 442 smp_ops.smp_prepare_cpus(max_cpus); 443 } 444} 445 446static void (*__smp_cross_call)(const struct cpumask *, unsigned int); 447 448void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int)) 449{ 450 if (!__smp_cross_call) 451 __smp_cross_call = fn; 452} 453 454static const char *ipi_types[NR_IPI] __tracepoint_string = { 455#define S(x,s) [x] = s 456 S(IPI_WAKEUP, "CPU wakeup interrupts"), 457 S(IPI_TIMER, "Timer broadcast interrupts"), 458 S(IPI_RESCHEDULE, "Rescheduling interrupts"), 459 S(IPI_CALL_FUNC, "Function call interrupts"), 460 S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"), 461 S(IPI_CPU_STOP, "CPU stop interrupts"), 462 S(IPI_IRQ_WORK, "IRQ work interrupts"), 463 S(IPI_COMPLETION, "completion interrupts"), 464}; 465 466static void smp_cross_call(const struct cpumask *target, unsigned int ipinr) 467{ 468 trace_ipi_raise(target, ipi_types[ipinr]); 469 __smp_cross_call(target, ipinr); 470} 471 472void show_ipi_list(struct seq_file *p, int prec) 473{ 474 unsigned int cpu, i; 475 476 for (i = 0; i < NR_IPI; i++) { 477 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i); 478 479 for_each_online_cpu(cpu) 480 seq_printf(p, "%10u ", 481 __get_irq_stat(cpu, ipi_irqs[i])); 482 483 seq_printf(p, " %s\n", ipi_types[i]); 484 } 485} 486 487u64 smp_irq_stat_cpu(unsigned int cpu) 488{ 489 u64 sum = 0; 490 int i; 491 492 for (i = 0; i < NR_IPI; i++) 493 sum += __get_irq_stat(cpu, ipi_irqs[i]); 494 495 return sum; 496} 497 498void arch_send_call_function_ipi_mask(const struct cpumask *mask) 499{ 500 smp_cross_call(mask, IPI_CALL_FUNC); 501} 502 503void arch_send_wakeup_ipi_mask(const struct cpumask *mask) 504{ 505 smp_cross_call(mask, IPI_WAKEUP); 506} 507 508void arch_send_call_function_single_ipi(int cpu) 509{ 510 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE); 511} 512 513#ifdef CONFIG_IRQ_WORK 514void arch_irq_work_raise(void) 515{ 516 if (arch_irq_work_has_interrupt()) 517 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK); 518} 519#endif 520 521#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 522void tick_broadcast(const struct cpumask *mask) 523{ 524 smp_cross_call(mask, IPI_TIMER); 525} 526#endif 527 528static DEFINE_RAW_SPINLOCK(stop_lock); 529 530/* 531 * ipi_cpu_stop - handle IPI from smp_send_stop() 532 */ 533static void ipi_cpu_stop(unsigned int cpu) 534{ 535 if (system_state == SYSTEM_BOOTING || 536 system_state == SYSTEM_RUNNING) { 537 raw_spin_lock(&stop_lock); 538 pr_crit("CPU%u: stopping\n", cpu); 539 dump_stack(); 540 raw_spin_unlock(&stop_lock); 541 } 542 543 set_cpu_online(cpu, false); 544 545 local_fiq_disable(); 546 local_irq_disable(); 547 548 while (1) 549 cpu_relax(); 550} 551 552static DEFINE_PER_CPU(struct completion *, cpu_completion); 553 554int register_ipi_completion(struct completion *completion, int cpu) 555{ 556 per_cpu(cpu_completion, cpu) = completion; 557 return IPI_COMPLETION; 558} 559 560static void ipi_complete(unsigned int cpu) 561{ 562 complete(per_cpu(cpu_completion, cpu)); 563} 564 565/* 566 * Main handler for inter-processor interrupts 567 */ 568asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs) 569{ 570 handle_IPI(ipinr, regs); 571} 572 573void handle_IPI(int ipinr, struct pt_regs *regs) 574{ 575 unsigned int cpu = smp_processor_id(); 576 struct pt_regs *old_regs = set_irq_regs(regs); 577 578 if ((unsigned)ipinr < NR_IPI) { 579 trace_ipi_entry_rcuidle(ipi_types[ipinr]); 580 __inc_irq_stat(cpu, ipi_irqs[ipinr]); 581 } 582 583 switch (ipinr) { 584 case IPI_WAKEUP: 585 break; 586 587#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 588 case IPI_TIMER: 589 irq_enter(); 590 tick_receive_broadcast(); 591 irq_exit(); 592 break; 593#endif 594 595 case IPI_RESCHEDULE: 596 scheduler_ipi(); 597 break; 598 599 case IPI_CALL_FUNC: 600 irq_enter(); 601 generic_smp_call_function_interrupt(); 602 irq_exit(); 603 break; 604 605 case IPI_CALL_FUNC_SINGLE: 606 irq_enter(); 607 generic_smp_call_function_single_interrupt(); 608 irq_exit(); 609 break; 610 611 case IPI_CPU_STOP: 612 irq_enter(); 613 ipi_cpu_stop(cpu); 614 irq_exit(); 615 break; 616 617#ifdef CONFIG_IRQ_WORK 618 case IPI_IRQ_WORK: 619 irq_enter(); 620 irq_work_run(); 621 irq_exit(); 622 break; 623#endif 624 625 case IPI_COMPLETION: 626 irq_enter(); 627 ipi_complete(cpu); 628 irq_exit(); 629 break; 630 631 default: 632 pr_crit("CPU%u: Unknown IPI message 0x%x\n", 633 cpu, ipinr); 634 break; 635 } 636 637 if ((unsigned)ipinr < NR_IPI) 638 trace_ipi_exit_rcuidle(ipi_types[ipinr]); 639 set_irq_regs(old_regs); 640} 641 642void smp_send_reschedule(int cpu) 643{ 644 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); 645} 646 647void smp_send_stop(void) 648{ 649 unsigned long timeout; 650 struct cpumask mask; 651 652 cpumask_copy(&mask, cpu_online_mask); 653 cpumask_clear_cpu(smp_processor_id(), &mask); 654 if (!cpumask_empty(&mask)) 655 smp_cross_call(&mask, IPI_CPU_STOP); 656 657 /* Wait up to one second for other CPUs to stop */ 658 timeout = USEC_PER_SEC; 659 while (num_online_cpus() > 1 && timeout--) 660 udelay(1); 661 662 if (num_online_cpus() > 1) 663 pr_warn("SMP: failed to stop secondary CPUs\n"); 664} 665 666/* 667 * not supported here 668 */ 669int setup_profiling_timer(unsigned int multiplier) 670{ 671 return -EINVAL; 672} 673 674#ifdef CONFIG_CPU_FREQ 675 676static DEFINE_PER_CPU(unsigned long, l_p_j_ref); 677static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq); 678static unsigned long global_l_p_j_ref; 679static unsigned long global_l_p_j_ref_freq; 680 681static int cpufreq_callback(struct notifier_block *nb, 682 unsigned long val, void *data) 683{ 684 struct cpufreq_freqs *freq = data; 685 int cpu = freq->cpu; 686 687 if (freq->flags & CPUFREQ_CONST_LOOPS) 688 return NOTIFY_OK; 689 690 if (!per_cpu(l_p_j_ref, cpu)) { 691 per_cpu(l_p_j_ref, cpu) = 692 per_cpu(cpu_data, cpu).loops_per_jiffy; 693 per_cpu(l_p_j_ref_freq, cpu) = freq->old; 694 if (!global_l_p_j_ref) { 695 global_l_p_j_ref = loops_per_jiffy; 696 global_l_p_j_ref_freq = freq->old; 697 } 698 } 699 700 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) || 701 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) { 702 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref, 703 global_l_p_j_ref_freq, 704 freq->new); 705 per_cpu(cpu_data, cpu).loops_per_jiffy = 706 cpufreq_scale(per_cpu(l_p_j_ref, cpu), 707 per_cpu(l_p_j_ref_freq, cpu), 708 freq->new); 709 } 710 return NOTIFY_OK; 711} 712 713static struct notifier_block cpufreq_notifier = { 714 .notifier_call = cpufreq_callback, 715}; 716 717static int __init register_cpufreq_notifier(void) 718{ 719 return cpufreq_register_notifier(&cpufreq_notifier, 720 CPUFREQ_TRANSITION_NOTIFIER); 721} 722core_initcall(register_cpufreq_notifier); 723 724#endif 725