1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * linux/arch/arm/kernel/smp.c 4 * 5 * Copyright (C) 2002 ARM Limited, All Rights Reserved. 6 */ 7#include <linux/module.h> 8#include <linux/delay.h> 9#include <linux/init.h> 10#include <linux/spinlock.h> 11#include <linux/sched/mm.h> 12#include <linux/sched/hotplug.h> 13#include <linux/sched/task_stack.h> 14#include <linux/interrupt.h> 15#include <linux/cache.h> 16#include <linux/profile.h> 17#include <linux/errno.h> 18#include <linux/mm.h> 19#include <linux/err.h> 20#include <linux/cpu.h> 21#include <linux/seq_file.h> 22#include <linux/irq.h> 23#include <linux/nmi.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#include <linux/kernel_stat.h> 30 31#include <linux/atomic.h> 32#include <asm/bugs.h> 33#include <asm/smp.h> 34#include <asm/cacheflush.h> 35#include <asm/cpu.h> 36#include <asm/cputype.h> 37#include <asm/exception.h> 38#include <asm/idmap.h> 39#include <asm/topology.h> 40#include <asm/mmu_context.h> 41#include <asm/procinfo.h> 42#include <asm/processor.h> 43#include <asm/sections.h> 44#include <asm/tlbflush.h> 45#include <asm/ptrace.h> 46#include <asm/smp_plat.h> 47#include <asm/virt.h> 48#include <asm/mach/arch.h> 49#include <asm/mpu.h> 50 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 60enum ipi_msg_type { 61 IPI_WAKEUP, 62 IPI_TIMER, 63 IPI_RESCHEDULE, 64 IPI_CALL_FUNC, 65 IPI_CPU_STOP, 66 IPI_IRQ_WORK, 67 IPI_COMPLETION, 68 NR_IPI, 69 /* 70 * CPU_BACKTRACE is special and not included in NR_IPI 71 * or tracable with trace_ipi_* 72 */ 73 IPI_CPU_BACKTRACE = NR_IPI, 74 /* 75 * SGI8-15 can be reserved by secure firmware, and thus may 76 * not be usable by the kernel. Please keep the above limited 77 * to at most 8 entries. 78 */ 79 MAX_IPI 80}; 81 82static int ipi_irq_base __read_mostly; 83static int nr_ipi __read_mostly = NR_IPI; 84static struct irq_desc *ipi_desc[MAX_IPI] __read_mostly; 85 86static void ipi_setup(int cpu); 87 88static DECLARE_COMPLETION(cpu_running); 89 90static struct smp_operations smp_ops __ro_after_init; 91 92void __init smp_set_ops(const struct smp_operations *ops) 93{ 94 if (ops) 95 smp_ops = *ops; 96}; 97 98static unsigned long get_arch_pgd(pgd_t *pgd) 99{ 100#ifdef CONFIG_ARM_LPAE 101 return __phys_to_pfn(virt_to_phys(pgd)); 102#else 103 return virt_to_phys(pgd); 104#endif 105} 106 107#if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR) 108static int secondary_biglittle_prepare(unsigned int cpu) 109{ 110 if (!cpu_vtable[cpu]) 111 cpu_vtable[cpu] = kzalloc(sizeof(*cpu_vtable[cpu]), GFP_KERNEL); 112 113 return cpu_vtable[cpu] ? 0 : -ENOMEM; 114} 115 116static void secondary_biglittle_init(void) 117{ 118 init_proc_vtable(lookup_processor(read_cpuid_id())->proc); 119} 120#else 121static int secondary_biglittle_prepare(unsigned int cpu) 122{ 123 return 0; 124} 125 126static void secondary_biglittle_init(void) 127{ 128} 129#endif 130 131int __cpu_up(unsigned int cpu, struct task_struct *idle) 132{ 133 int ret; 134 135 if (!smp_ops.smp_boot_secondary) 136 return -ENOSYS; 137 138 ret = secondary_biglittle_prepare(cpu); 139 if (ret) 140 return ret; 141 142 /* 143 * We need to tell the secondary core where to find 144 * its stack and the page tables. 145 */ 146 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP; 147#ifdef CONFIG_ARM_MPU 148 secondary_data.mpu_rgn_info = &mpu_rgn_info; 149#endif 150 151#ifdef CONFIG_MMU 152 secondary_data.pgdir = virt_to_phys(idmap_pgd); 153 secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir); 154#endif 155 secondary_data.task = idle; 156 sync_cache_w(&secondary_data); 157 158 /* 159 * Now bring the CPU into our world. 160 */ 161 ret = smp_ops.smp_boot_secondary(cpu, idle); 162 if (ret == 0) { 163 /* 164 * CPU was successfully started, wait for it 165 * to come online or time out. 166 */ 167 wait_for_completion_timeout(&cpu_running, 168 msecs_to_jiffies(1000)); 169 170 if (!cpu_online(cpu)) { 171 pr_crit("CPU%u: failed to come online\n", cpu); 172 ret = -EIO; 173 } 174 } else { 175 pr_err("CPU%u: failed to boot: %d\n", cpu, ret); 176 } 177 178 179 memset(&secondary_data, 0, sizeof(secondary_data)); 180 return ret; 181} 182 183/* platform specific SMP operations */ 184void __init smp_init_cpus(void) 185{ 186 if (smp_ops.smp_init_cpus) 187 smp_ops.smp_init_cpus(); 188} 189 190int platform_can_secondary_boot(void) 191{ 192 return !!smp_ops.smp_boot_secondary; 193} 194 195int platform_can_cpu_hotplug(void) 196{ 197#ifdef CONFIG_HOTPLUG_CPU 198 if (smp_ops.cpu_kill) 199 return 1; 200#endif 201 202 return 0; 203} 204 205#ifdef CONFIG_HOTPLUG_CPU 206static int platform_cpu_kill(unsigned int cpu) 207{ 208 if (smp_ops.cpu_kill) 209 return smp_ops.cpu_kill(cpu); 210 return 1; 211} 212 213static int platform_cpu_disable(unsigned int cpu) 214{ 215 if (smp_ops.cpu_disable) 216 return smp_ops.cpu_disable(cpu); 217 218 return 0; 219} 220 221int platform_can_hotplug_cpu(unsigned int cpu) 222{ 223 /* cpu_die must be specified to support hotplug */ 224 if (!smp_ops.cpu_die) 225 return 0; 226 227 if (smp_ops.cpu_can_disable) 228 return smp_ops.cpu_can_disable(cpu); 229 230 /* 231 * By default, allow disabling all CPUs except the first one, 232 * since this is special on a lot of platforms, e.g. because 233 * of clock tick interrupts. 234 */ 235 return cpu != 0; 236} 237 238static void ipi_teardown(int cpu) 239{ 240 int i; 241 242 if (WARN_ON_ONCE(!ipi_irq_base)) 243 return; 244 245 for (i = 0; i < nr_ipi; i++) 246 disable_percpu_irq(ipi_irq_base + i); 247} 248 249/* 250 * __cpu_disable runs on the processor to be shutdown. 251 */ 252int __cpu_disable(void) 253{ 254 unsigned int cpu = smp_processor_id(); 255 int ret; 256 257 ret = platform_cpu_disable(cpu); 258 if (ret) 259 return ret; 260 261#ifdef CONFIG_GENERIC_ARCH_TOPOLOGY 262 remove_cpu_topology(cpu); 263#endif 264 265 /* 266 * Take this CPU offline. Once we clear this, we can't return, 267 * and we must not schedule until we're ready to give up the cpu. 268 */ 269 set_cpu_online(cpu, false); 270 ipi_teardown(cpu); 271 272 /* 273 * OK - migrate IRQs away from this CPU 274 */ 275 irq_migrate_all_off_this_cpu(); 276 277 /* 278 * Flush user cache and TLB mappings, and then remove this CPU 279 * from the vm mask set of all processes. 280 * 281 * Caches are flushed to the Level of Unification Inner Shareable 282 * to write-back dirty lines to unified caches shared by all CPUs. 283 */ 284 flush_cache_louis(); 285 local_flush_tlb_all(); 286 287 return 0; 288} 289 290/* 291 * called on the thread which is asking for a CPU to be shutdown after the 292 * shutdown completed. 293 */ 294void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu) 295{ 296 pr_debug("CPU%u: shutdown\n", cpu); 297 298 clear_tasks_mm_cpumask(cpu); 299 /* 300 * platform_cpu_kill() is generally expected to do the powering off 301 * and/or cutting of clocks to the dying CPU. Optionally, this may 302 * be done by the CPU which is dying in preference to supporting 303 * this call, but that means there is _no_ synchronisation between 304 * the requesting CPU and the dying CPU actually losing power. 305 */ 306 if (!platform_cpu_kill(cpu)) 307 pr_err("CPU%u: unable to kill\n", cpu); 308} 309 310/* 311 * Called from the idle thread for the CPU which has been shutdown. 312 * 313 * Note that we disable IRQs here, but do not re-enable them 314 * before returning to the caller. This is also the behaviour 315 * of the other hotplug-cpu capable cores, so presumably coming 316 * out of idle fixes this. 317 */ 318void __noreturn arch_cpu_idle_dead(void) 319{ 320 unsigned int cpu = smp_processor_id(); 321 322 idle_task_exit(); 323 324 local_irq_disable(); 325 326 /* 327 * Flush the data out of the L1 cache for this CPU. This must be 328 * before the completion to ensure that data is safely written out 329 * before platform_cpu_kill() gets called - which may disable 330 * *this* CPU and power down its cache. 331 */ 332 flush_cache_louis(); 333 334 /* 335 * Tell cpuhp_bp_sync_dead() that this CPU is now safe to dispose 336 * of. Once this returns, power and/or clocks can be removed at 337 * any point from this CPU and its cache by platform_cpu_kill(). 338 */ 339 cpuhp_ap_report_dead(); 340 341 /* 342 * Ensure that the cache lines associated with that completion are 343 * written out. This covers the case where _this_ CPU is doing the 344 * powering down, to ensure that the completion is visible to the 345 * CPU waiting for this one. 346 */ 347 flush_cache_louis(); 348 349 /* 350 * The actual CPU shutdown procedure is at least platform (if not 351 * CPU) specific. This may remove power, or it may simply spin. 352 * 353 * Platforms are generally expected *NOT* to return from this call, 354 * although there are some which do because they have no way to 355 * power down the CPU. These platforms are the _only_ reason we 356 * have a return path which uses the fragment of assembly below. 357 * 358 * The return path should not be used for platforms which can 359 * power off the CPU. 360 */ 361 if (smp_ops.cpu_die) 362 smp_ops.cpu_die(cpu); 363 364 pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n", 365 cpu); 366 367 /* 368 * Do not return to the idle loop - jump back to the secondary 369 * cpu initialisation. There's some initialisation which needs 370 * to be repeated to undo the effects of taking the CPU offline. 371 */ 372 __asm__("mov sp, %0\n" 373 " mov fp, #0\n" 374 " mov r0, %1\n" 375 " b secondary_start_kernel" 376 : 377 : "r" (task_stack_page(current) + THREAD_SIZE - 8), 378 "r" (current) 379 : "r0"); 380 381 unreachable(); 382} 383#endif /* CONFIG_HOTPLUG_CPU */ 384 385/* 386 * Called by both boot and secondaries to move global data into 387 * per-processor storage. 388 */ 389static void smp_store_cpu_info(unsigned int cpuid) 390{ 391 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid); 392 393 cpu_info->loops_per_jiffy = loops_per_jiffy; 394 cpu_info->cpuid = read_cpuid_id(); 395 396 store_cpu_topology(cpuid); 397 check_cpu_icache_size(cpuid); 398} 399 400static void set_current(struct task_struct *cur) 401{ 402 /* Set TPIDRURO */ 403 asm("mcr p15, 0, %0, c13, c0, 3" :: "r"(cur) : "memory"); 404} 405 406/* 407 * This is the secondary CPU boot entry. We're using this CPUs 408 * idle thread stack, but a set of temporary page tables. 409 */ 410asmlinkage void secondary_start_kernel(struct task_struct *task) 411{ 412 struct mm_struct *mm = &init_mm; 413 unsigned int cpu; 414 415 set_current(task); 416 417 secondary_biglittle_init(); 418 419 /* 420 * The identity mapping is uncached (strongly ordered), so 421 * switch away from it before attempting any exclusive accesses. 422 */ 423 cpu_switch_mm(mm->pgd, mm); 424 local_flush_bp_all(); 425 enter_lazy_tlb(mm, current); 426 local_flush_tlb_all(); 427 428 /* 429 * All kernel threads share the same mm context; grab a 430 * reference and switch to it. 431 */ 432 cpu = smp_processor_id(); 433 mmgrab(mm); 434 current->active_mm = mm; 435 cpumask_set_cpu(cpu, mm_cpumask(mm)); 436 437 cpu_init(); 438 439#ifndef CONFIG_MMU 440 setup_vectors_base(); 441#endif 442 pr_debug("CPU%u: Booted secondary processor\n", cpu); 443 444 trace_hardirqs_off(); 445 446 /* 447 * Give the platform a chance to do its own initialisation. 448 */ 449 if (smp_ops.smp_secondary_init) 450 smp_ops.smp_secondary_init(cpu); 451 452 notify_cpu_starting(cpu); 453 454 ipi_setup(cpu); 455 456 calibrate_delay(); 457 458 smp_store_cpu_info(cpu); 459 460 /* 461 * OK, now it's safe to let the boot CPU continue. Wait for 462 * the CPU migration code to notice that the CPU is online 463 * before we continue - which happens after __cpu_up returns. 464 */ 465 set_cpu_online(cpu, true); 466 467 check_other_bugs(); 468 469 complete(&cpu_running); 470 471 local_irq_enable(); 472 local_fiq_enable(); 473 local_abt_enable(); 474 475 /* 476 * OK, it's off to the idle thread for us 477 */ 478 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 479} 480 481void __init smp_cpus_done(unsigned int max_cpus) 482{ 483 int cpu; 484 unsigned long bogosum = 0; 485 486 for_each_online_cpu(cpu) 487 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy; 488 489 printk(KERN_INFO "SMP: Total of %d processors activated " 490 "(%lu.%02lu BogoMIPS).\n", 491 num_online_cpus(), 492 bogosum / (500000/HZ), 493 (bogosum / (5000/HZ)) % 100); 494 495 hyp_mode_check(); 496} 497 498void __init smp_prepare_boot_cpu(void) 499{ 500 set_my_cpu_offset(per_cpu_offset(smp_processor_id())); 501} 502 503void __init smp_prepare_cpus(unsigned int max_cpus) 504{ 505 unsigned int ncores = num_possible_cpus(); 506 507 init_cpu_topology(); 508 509 smp_store_cpu_info(smp_processor_id()); 510 511 /* 512 * are we trying to boot more cores than exist? 513 */ 514 if (max_cpus > ncores) 515 max_cpus = ncores; 516 if (ncores > 1 && max_cpus) { 517 /* 518 * Initialise the present map, which describes the set of CPUs 519 * actually populated at the present time. A platform should 520 * re-initialize the map in the platforms smp_prepare_cpus() 521 * if present != possible (e.g. physical hotplug). 522 */ 523 init_cpu_present(cpu_possible_mask); 524 525 /* 526 * Initialise the SCU if there are more than one CPU 527 * and let them know where to start. 528 */ 529 if (smp_ops.smp_prepare_cpus) 530 smp_ops.smp_prepare_cpus(max_cpus); 531 } 532} 533 534static const char *ipi_types[NR_IPI] __tracepoint_string = { 535 [IPI_WAKEUP] = "CPU wakeup interrupts", 536 [IPI_TIMER] = "Timer broadcast interrupts", 537 [IPI_RESCHEDULE] = "Rescheduling interrupts", 538 [IPI_CALL_FUNC] = "Function call interrupts", 539 [IPI_CPU_STOP] = "CPU stop interrupts", 540 [IPI_IRQ_WORK] = "IRQ work interrupts", 541 [IPI_COMPLETION] = "completion interrupts", 542}; 543 544static void smp_cross_call(const struct cpumask *target, unsigned int ipinr); 545 546void show_ipi_list(struct seq_file *p, int prec) 547{ 548 unsigned int cpu, i; 549 550 for (i = 0; i < NR_IPI; i++) { 551 if (!ipi_desc[i]) 552 continue; 553 554 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i); 555 556 for_each_online_cpu(cpu) 557 seq_printf(p, "%10u ", irq_desc_kstat_cpu(ipi_desc[i], cpu)); 558 559 seq_printf(p, " %s\n", ipi_types[i]); 560 } 561} 562 563void arch_send_call_function_ipi_mask(const struct cpumask *mask) 564{ 565 smp_cross_call(mask, IPI_CALL_FUNC); 566} 567 568void arch_send_wakeup_ipi_mask(const struct cpumask *mask) 569{ 570 smp_cross_call(mask, IPI_WAKEUP); 571} 572 573void arch_send_call_function_single_ipi(int cpu) 574{ 575 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC); 576} 577 578#ifdef CONFIG_IRQ_WORK 579void arch_irq_work_raise(void) 580{ 581 if (arch_irq_work_has_interrupt()) 582 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK); 583} 584#endif 585 586#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 587void tick_broadcast(const struct cpumask *mask) 588{ 589 smp_cross_call(mask, IPI_TIMER); 590} 591#endif 592 593static DEFINE_RAW_SPINLOCK(stop_lock); 594 595/* 596 * ipi_cpu_stop - handle IPI from smp_send_stop() 597 */ 598static void ipi_cpu_stop(unsigned int cpu) 599{ 600 local_fiq_disable(); 601 602 if (system_state <= SYSTEM_RUNNING) { 603 raw_spin_lock(&stop_lock); 604 pr_crit("CPU%u: stopping\n", cpu); 605 dump_stack(); 606 raw_spin_unlock(&stop_lock); 607 } 608 609 set_cpu_online(cpu, false); 610 611 while (1) { 612 cpu_relax(); 613 wfe(); 614 } 615} 616 617static DEFINE_PER_CPU(struct completion *, cpu_completion); 618 619int register_ipi_completion(struct completion *completion, int cpu) 620{ 621 per_cpu(cpu_completion, cpu) = completion; 622 return IPI_COMPLETION; 623} 624 625static void ipi_complete(unsigned int cpu) 626{ 627 complete(per_cpu(cpu_completion, cpu)); 628} 629 630/* 631 * Main handler for inter-processor interrupts 632 */ 633static void do_handle_IPI(int ipinr) 634{ 635 unsigned int cpu = smp_processor_id(); 636 637 if ((unsigned)ipinr < NR_IPI) 638 trace_ipi_entry(ipi_types[ipinr]); 639 640 switch (ipinr) { 641 case IPI_WAKEUP: 642 break; 643 644#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 645 case IPI_TIMER: 646 tick_receive_broadcast(); 647 break; 648#endif 649 650 case IPI_RESCHEDULE: 651 scheduler_ipi(); 652 break; 653 654 case IPI_CALL_FUNC: 655 generic_smp_call_function_interrupt(); 656 break; 657 658 case IPI_CPU_STOP: 659 ipi_cpu_stop(cpu); 660 break; 661 662#ifdef CONFIG_IRQ_WORK 663 case IPI_IRQ_WORK: 664 irq_work_run(); 665 break; 666#endif 667 668 case IPI_COMPLETION: 669 ipi_complete(cpu); 670 break; 671 672 case IPI_CPU_BACKTRACE: 673 printk_deferred_enter(); 674 nmi_cpu_backtrace(get_irq_regs()); 675 printk_deferred_exit(); 676 break; 677 678 default: 679 pr_crit("CPU%u: Unknown IPI message 0x%x\n", 680 cpu, ipinr); 681 break; 682 } 683 684 if ((unsigned)ipinr < NR_IPI) 685 trace_ipi_exit(ipi_types[ipinr]); 686} 687 688/* Legacy version, should go away once all irqchips have been converted */ 689void handle_IPI(int ipinr, struct pt_regs *regs) 690{ 691 struct pt_regs *old_regs = set_irq_regs(regs); 692 693 irq_enter(); 694 do_handle_IPI(ipinr); 695 irq_exit(); 696 697 set_irq_regs(old_regs); 698} 699 700static irqreturn_t ipi_handler(int irq, void *data) 701{ 702 do_handle_IPI(irq - ipi_irq_base); 703 return IRQ_HANDLED; 704} 705 706static void smp_cross_call(const struct cpumask *target, unsigned int ipinr) 707{ 708 trace_ipi_raise(target, ipi_types[ipinr]); 709 __ipi_send_mask(ipi_desc[ipinr], target); 710} 711 712static void ipi_setup(int cpu) 713{ 714 int i; 715 716 if (WARN_ON_ONCE(!ipi_irq_base)) 717 return; 718 719 for (i = 0; i < nr_ipi; i++) 720 enable_percpu_irq(ipi_irq_base + i, 0); 721} 722 723void __init set_smp_ipi_range(int ipi_base, int n) 724{ 725 int i; 726 727 WARN_ON(n < MAX_IPI); 728 nr_ipi = min(n, MAX_IPI); 729 730 for (i = 0; i < nr_ipi; i++) { 731 int err; 732 733 err = request_percpu_irq(ipi_base + i, ipi_handler, 734 "IPI", &irq_stat); 735 WARN_ON(err); 736 737 ipi_desc[i] = irq_to_desc(ipi_base + i); 738 irq_set_status_flags(ipi_base + i, IRQ_HIDDEN); 739 } 740 741 ipi_irq_base = ipi_base; 742 743 /* Setup the boot CPU immediately */ 744 ipi_setup(smp_processor_id()); 745} 746 747void arch_smp_send_reschedule(int cpu) 748{ 749 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); 750} 751 752void smp_send_stop(void) 753{ 754 unsigned long timeout; 755 struct cpumask mask; 756 757 cpumask_copy(&mask, cpu_online_mask); 758 cpumask_clear_cpu(smp_processor_id(), &mask); 759 if (!cpumask_empty(&mask)) 760 smp_cross_call(&mask, IPI_CPU_STOP); 761 762 /* Wait up to one second for other CPUs to stop */ 763 timeout = USEC_PER_SEC; 764 while (num_online_cpus() > 1 && timeout--) 765 udelay(1); 766 767 if (num_online_cpus() > 1) 768 pr_warn("SMP: failed to stop secondary CPUs\n"); 769} 770 771/* In case panic() and panic() called at the same time on CPU1 and CPU2, 772 * and CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop() 773 * CPU1 can't receive the ipi irqs from CPU2, CPU1 will be always online, 774 * kdump fails. So split out the panic_smp_self_stop() and add 775 * set_cpu_online(smp_processor_id(), false). 776 */ 777void __noreturn panic_smp_self_stop(void) 778{ 779 pr_debug("CPU %u will stop doing anything useful since another CPU has paniced\n", 780 smp_processor_id()); 781 set_cpu_online(smp_processor_id(), false); 782 while (1) 783 cpu_relax(); 784} 785 786#ifdef CONFIG_CPU_FREQ 787 788static DEFINE_PER_CPU(unsigned long, l_p_j_ref); 789static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq); 790static unsigned long global_l_p_j_ref; 791static unsigned long global_l_p_j_ref_freq; 792 793static int cpufreq_callback(struct notifier_block *nb, 794 unsigned long val, void *data) 795{ 796 struct cpufreq_freqs *freq = data; 797 struct cpumask *cpus = freq->policy->cpus; 798 int cpu, first = cpumask_first(cpus); 799 unsigned int lpj; 800 801 if (freq->flags & CPUFREQ_CONST_LOOPS) 802 return NOTIFY_OK; 803 804 if (!per_cpu(l_p_j_ref, first)) { 805 for_each_cpu(cpu, cpus) { 806 per_cpu(l_p_j_ref, cpu) = 807 per_cpu(cpu_data, cpu).loops_per_jiffy; 808 per_cpu(l_p_j_ref_freq, cpu) = freq->old; 809 } 810 811 if (!global_l_p_j_ref) { 812 global_l_p_j_ref = loops_per_jiffy; 813 global_l_p_j_ref_freq = freq->old; 814 } 815 } 816 817 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) || 818 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) { 819 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref, 820 global_l_p_j_ref_freq, 821 freq->new); 822 823 lpj = cpufreq_scale(per_cpu(l_p_j_ref, first), 824 per_cpu(l_p_j_ref_freq, first), freq->new); 825 for_each_cpu(cpu, cpus) 826 per_cpu(cpu_data, cpu).loops_per_jiffy = lpj; 827 } 828 return NOTIFY_OK; 829} 830 831static struct notifier_block cpufreq_notifier = { 832 .notifier_call = cpufreq_callback, 833}; 834 835static int __init register_cpufreq_notifier(void) 836{ 837 return cpufreq_register_notifier(&cpufreq_notifier, 838 CPUFREQ_TRANSITION_NOTIFIER); 839} 840core_initcall(register_cpufreq_notifier); 841 842#endif 843 844static void raise_nmi(cpumask_t *mask) 845{ 846 __ipi_send_mask(ipi_desc[IPI_CPU_BACKTRACE], mask); 847} 848 849void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu) 850{ 851 nmi_trigger_cpumask_backtrace(mask, exclude_cpu, raise_nmi); 852} 853