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 #define CREATE_TRACE_POINTS 52 #include <trace/events/ipi.h> 53 54 /* 55 * as from 2.5, kernels no longer have an init_tasks structure 56 * so we need some other way of telling a new secondary core 57 * where to place its SVC stack 58 */ 59 struct secondary_data secondary_data; 60 61 enum ipi_msg_type { 62 IPI_WAKEUP, 63 IPI_TIMER, 64 IPI_RESCHEDULE, 65 IPI_CALL_FUNC, 66 IPI_CPU_STOP, 67 IPI_IRQ_WORK, 68 IPI_COMPLETION, 69 NR_IPI, 70 /* 71 * CPU_BACKTRACE is special and not included in NR_IPI 72 * or tracable with trace_ipi_* 73 */ 74 IPI_CPU_BACKTRACE = NR_IPI, 75 /* 76 * SGI8-15 can be reserved by secure firmware, and thus may 77 * not be usable by the kernel. Please keep the above limited 78 * to at most 8 entries. 79 */ 80 MAX_IPI 81 }; 82 83 static int ipi_irq_base __read_mostly; 84 static int nr_ipi __read_mostly = NR_IPI; 85 static struct irq_desc *ipi_desc[MAX_IPI] __read_mostly; 86 87 static void ipi_setup(int cpu); 88 89 static DECLARE_COMPLETION(cpu_running); 90 91 static struct smp_operations smp_ops __ro_after_init; 92 93 void __init smp_set_ops(const struct smp_operations *ops) 94 { 95 if (ops) 96 smp_ops = *ops; 97 }; 98 99 static unsigned long get_arch_pgd(pgd_t *pgd) 100 { 101 #ifdef CONFIG_ARM_LPAE 102 return __phys_to_pfn(virt_to_phys(pgd)); 103 #else 104 return virt_to_phys(pgd); 105 #endif 106 } 107 108 #if defined(CONFIG_BIG_LITTLE) && defined(CONFIG_HARDEN_BRANCH_PREDICTOR) 109 static int secondary_biglittle_prepare(unsigned int cpu) 110 { 111 if (!cpu_vtable[cpu]) 112 cpu_vtable[cpu] = kzalloc(sizeof(*cpu_vtable[cpu]), GFP_KERNEL); 113 114 return cpu_vtable[cpu] ? 0 : -ENOMEM; 115 } 116 117 static void secondary_biglittle_init(void) 118 { 119 init_proc_vtable(lookup_processor(read_cpuid_id())->proc); 120 } 121 #else 122 static int secondary_biglittle_prepare(unsigned int cpu) 123 { 124 return 0; 125 } 126 127 static void secondary_biglittle_init(void) 128 { 129 } 130 #endif 131 132 int __cpu_up(unsigned int cpu, struct task_struct *idle) 133 { 134 int ret; 135 136 if (!smp_ops.smp_boot_secondary) 137 return -ENOSYS; 138 139 ret = secondary_biglittle_prepare(cpu); 140 if (ret) 141 return ret; 142 143 /* 144 * We need to tell the secondary core where to find 145 * its stack and the page tables. 146 */ 147 secondary_data.stack = task_stack_page(idle) + THREAD_START_SP; 148 #ifdef CONFIG_ARM_MPU 149 secondary_data.mpu_rgn_info = &mpu_rgn_info; 150 #endif 151 152 #ifdef CONFIG_MMU 153 secondary_data.pgdir = virt_to_phys(idmap_pgd); 154 secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir); 155 #endif 156 secondary_data.task = idle; 157 sync_cache_w(&secondary_data); 158 159 /* 160 * Now bring the CPU into our world. 161 */ 162 ret = smp_ops.smp_boot_secondary(cpu, idle); 163 if (ret == 0) { 164 /* 165 * CPU was successfully started, wait for it 166 * to come online or time out. 167 */ 168 wait_for_completion_timeout(&cpu_running, 169 msecs_to_jiffies(1000)); 170 171 if (!cpu_online(cpu)) { 172 pr_crit("CPU%u: failed to come online\n", cpu); 173 ret = -EIO; 174 } 175 } else { 176 pr_err("CPU%u: failed to boot: %d\n", cpu, ret); 177 } 178 179 180 memset(&secondary_data, 0, sizeof(secondary_data)); 181 return ret; 182 } 183 184 /* platform specific SMP operations */ 185 void __init smp_init_cpus(void) 186 { 187 if (smp_ops.smp_init_cpus) 188 smp_ops.smp_init_cpus(); 189 } 190 191 int platform_can_secondary_boot(void) 192 { 193 return !!smp_ops.smp_boot_secondary; 194 } 195 196 int platform_can_cpu_hotplug(void) 197 { 198 #ifdef CONFIG_HOTPLUG_CPU 199 if (smp_ops.cpu_kill) 200 return 1; 201 #endif 202 203 return 0; 204 } 205 206 #ifdef CONFIG_HOTPLUG_CPU 207 static int platform_cpu_kill(unsigned int cpu) 208 { 209 if (smp_ops.cpu_kill) 210 return smp_ops.cpu_kill(cpu); 211 return 1; 212 } 213 214 static int platform_cpu_disable(unsigned int cpu) 215 { 216 if (smp_ops.cpu_disable) 217 return smp_ops.cpu_disable(cpu); 218 219 return 0; 220 } 221 222 int platform_can_hotplug_cpu(unsigned int cpu) 223 { 224 /* cpu_die must be specified to support hotplug */ 225 if (!smp_ops.cpu_die) 226 return 0; 227 228 if (smp_ops.cpu_can_disable) 229 return smp_ops.cpu_can_disable(cpu); 230 231 /* 232 * By default, allow disabling all CPUs except the first one, 233 * since this is special on a lot of platforms, e.g. because 234 * of clock tick interrupts. 235 */ 236 return cpu != 0; 237 } 238 239 static void ipi_teardown(int cpu) 240 { 241 int i; 242 243 if (WARN_ON_ONCE(!ipi_irq_base)) 244 return; 245 246 for (i = 0; i < nr_ipi; i++) 247 disable_percpu_irq(ipi_irq_base + i); 248 } 249 250 /* 251 * __cpu_disable runs on the processor to be shutdown. 252 */ 253 int __cpu_disable(void) 254 { 255 unsigned int cpu = smp_processor_id(); 256 int ret; 257 258 ret = platform_cpu_disable(cpu); 259 if (ret) 260 return ret; 261 262 #ifdef CONFIG_GENERIC_ARCH_TOPOLOGY 263 remove_cpu_topology(cpu); 264 #endif 265 266 /* 267 * Take this CPU offline. Once we clear this, we can't return, 268 * and we must not schedule until we're ready to give up the cpu. 269 */ 270 set_cpu_online(cpu, false); 271 ipi_teardown(cpu); 272 273 /* 274 * OK - migrate IRQs away from this CPU 275 */ 276 irq_migrate_all_off_this_cpu(); 277 278 /* 279 * Flush user cache and TLB mappings, and then remove this CPU 280 * from the vm mask set of all processes. 281 * 282 * Caches are flushed to the Level of Unification Inner Shareable 283 * to write-back dirty lines to unified caches shared by all CPUs. 284 */ 285 flush_cache_louis(); 286 local_flush_tlb_all(); 287 288 return 0; 289 } 290 291 /* 292 * called on the thread which is asking for a CPU to be shutdown - 293 * waits until shutdown has completed, or it is timed out. 294 */ 295 void __cpu_die(unsigned int cpu) 296 { 297 if (!cpu_wait_death(cpu, 5)) { 298 pr_err("CPU%u: cpu didn't die\n", cpu); 299 return; 300 } 301 pr_debug("CPU%u: shutdown\n", cpu); 302 303 clear_tasks_mm_cpumask(cpu); 304 /* 305 * platform_cpu_kill() is generally expected to do the powering off 306 * and/or cutting of clocks to the dying CPU. Optionally, this may 307 * be done by the CPU which is dying in preference to supporting 308 * this call, but that means there is _no_ synchronisation between 309 * the requesting CPU and the dying CPU actually losing power. 310 */ 311 if (!platform_cpu_kill(cpu)) 312 pr_err("CPU%u: unable to kill\n", cpu); 313 } 314 315 /* 316 * Called from the idle thread for the CPU which has been shutdown. 317 * 318 * Note that we disable IRQs here, but do not re-enable them 319 * before returning to the caller. This is also the behaviour 320 * of the other hotplug-cpu capable cores, so presumably coming 321 * out of idle fixes this. 322 */ 323 void arch_cpu_idle_dead(void) 324 { 325 unsigned int cpu = smp_processor_id(); 326 327 idle_task_exit(); 328 329 local_irq_disable(); 330 331 /* 332 * Flush the data out of the L1 cache for this CPU. This must be 333 * before the completion to ensure that data is safely written out 334 * before platform_cpu_kill() gets called - which may disable 335 * *this* CPU and power down its cache. 336 */ 337 flush_cache_louis(); 338 339 /* 340 * Tell __cpu_die() that this CPU is now safe to dispose of. Once 341 * this returns, power and/or clocks can be removed at any point 342 * from this CPU and its cache by platform_cpu_kill(). 343 */ 344 (void)cpu_report_death(); 345 346 /* 347 * Ensure that the cache lines associated with that completion are 348 * written out. This covers the case where _this_ CPU is doing the 349 * powering down, to ensure that the completion is visible to the 350 * CPU waiting for this one. 351 */ 352 flush_cache_louis(); 353 354 /* 355 * The actual CPU shutdown procedure is at least platform (if not 356 * CPU) specific. This may remove power, or it may simply spin. 357 * 358 * Platforms are generally expected *NOT* to return from this call, 359 * although there are some which do because they have no way to 360 * power down the CPU. These platforms are the _only_ reason we 361 * have a return path which uses the fragment of assembly below. 362 * 363 * The return path should not be used for platforms which can 364 * power off the CPU. 365 */ 366 if (smp_ops.cpu_die) 367 smp_ops.cpu_die(cpu); 368 369 pr_warn("CPU%u: smp_ops.cpu_die() returned, trying to resuscitate\n", 370 cpu); 371 372 /* 373 * Do not return to the idle loop - jump back to the secondary 374 * cpu initialisation. There's some initialisation which needs 375 * to be repeated to undo the effects of taking the CPU offline. 376 */ 377 __asm__("mov sp, %0\n" 378 " mov fp, #0\n" 379 " mov r0, %1\n" 380 " b secondary_start_kernel" 381 : 382 : "r" (task_stack_page(current) + THREAD_SIZE - 8), 383 "r" (current) 384 : "r0"); 385 } 386 #endif /* CONFIG_HOTPLUG_CPU */ 387 388 /* 389 * Called by both boot and secondaries to move global data into 390 * per-processor storage. 391 */ 392 static void smp_store_cpu_info(unsigned int cpuid) 393 { 394 struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid); 395 396 cpu_info->loops_per_jiffy = loops_per_jiffy; 397 cpu_info->cpuid = read_cpuid_id(); 398 399 store_cpu_topology(cpuid); 400 check_cpu_icache_size(cpuid); 401 } 402 403 static void set_current(struct task_struct *cur) 404 { 405 /* Set TPIDRURO */ 406 asm("mcr p15, 0, %0, c13, c0, 3" :: "r"(cur) : "memory"); 407 } 408 409 /* 410 * This is the secondary CPU boot entry. We're using this CPUs 411 * idle thread stack, but a set of temporary page tables. 412 */ 413 asmlinkage void secondary_start_kernel(struct task_struct *task) 414 { 415 struct mm_struct *mm = &init_mm; 416 unsigned int cpu; 417 418 set_current(task); 419 420 secondary_biglittle_init(); 421 422 /* 423 * The identity mapping is uncached (strongly ordered), so 424 * switch away from it before attempting any exclusive accesses. 425 */ 426 cpu_switch_mm(mm->pgd, mm); 427 local_flush_bp_all(); 428 enter_lazy_tlb(mm, current); 429 local_flush_tlb_all(); 430 431 /* 432 * All kernel threads share the same mm context; grab a 433 * reference and switch to it. 434 */ 435 cpu = smp_processor_id(); 436 mmgrab(mm); 437 current->active_mm = mm; 438 cpumask_set_cpu(cpu, mm_cpumask(mm)); 439 440 cpu_init(); 441 442 #ifndef CONFIG_MMU 443 setup_vectors_base(); 444 #endif 445 pr_debug("CPU%u: Booted secondary processor\n", cpu); 446 447 trace_hardirqs_off(); 448 449 /* 450 * Give the platform a chance to do its own initialisation. 451 */ 452 if (smp_ops.smp_secondary_init) 453 smp_ops.smp_secondary_init(cpu); 454 455 notify_cpu_starting(cpu); 456 457 ipi_setup(cpu); 458 459 calibrate_delay(); 460 461 smp_store_cpu_info(cpu); 462 463 /* 464 * OK, now it's safe to let the boot CPU continue. Wait for 465 * the CPU migration code to notice that the CPU is online 466 * before we continue - which happens after __cpu_up returns. 467 */ 468 set_cpu_online(cpu, true); 469 470 check_other_bugs(); 471 472 complete(&cpu_running); 473 474 local_irq_enable(); 475 local_fiq_enable(); 476 local_abt_enable(); 477 478 /* 479 * OK, it's off to the idle thread for us 480 */ 481 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 482 } 483 484 void __init smp_cpus_done(unsigned int max_cpus) 485 { 486 int cpu; 487 unsigned long bogosum = 0; 488 489 for_each_online_cpu(cpu) 490 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy; 491 492 printk(KERN_INFO "SMP: Total of %d processors activated " 493 "(%lu.%02lu BogoMIPS).\n", 494 num_online_cpus(), 495 bogosum / (500000/HZ), 496 (bogosum / (5000/HZ)) % 100); 497 498 hyp_mode_check(); 499 } 500 501 void __init smp_prepare_boot_cpu(void) 502 { 503 set_my_cpu_offset(per_cpu_offset(smp_processor_id())); 504 } 505 506 void __init smp_prepare_cpus(unsigned int max_cpus) 507 { 508 unsigned int ncores = num_possible_cpus(); 509 510 init_cpu_topology(); 511 512 smp_store_cpu_info(smp_processor_id()); 513 514 /* 515 * are we trying to boot more cores than exist? 516 */ 517 if (max_cpus > ncores) 518 max_cpus = ncores; 519 if (ncores > 1 && max_cpus) { 520 /* 521 * Initialise the present map, which describes the set of CPUs 522 * actually populated at the present time. A platform should 523 * re-initialize the map in the platforms smp_prepare_cpus() 524 * if present != possible (e.g. physical hotplug). 525 */ 526 init_cpu_present(cpu_possible_mask); 527 528 /* 529 * Initialise the SCU if there are more than one CPU 530 * and let them know where to start. 531 */ 532 if (smp_ops.smp_prepare_cpus) 533 smp_ops.smp_prepare_cpus(max_cpus); 534 } 535 } 536 537 static const char *ipi_types[NR_IPI] __tracepoint_string = { 538 [IPI_WAKEUP] = "CPU wakeup interrupts", 539 [IPI_TIMER] = "Timer broadcast interrupts", 540 [IPI_RESCHEDULE] = "Rescheduling interrupts", 541 [IPI_CALL_FUNC] = "Function call interrupts", 542 [IPI_CPU_STOP] = "CPU stop interrupts", 543 [IPI_IRQ_WORK] = "IRQ work interrupts", 544 [IPI_COMPLETION] = "completion interrupts", 545 }; 546 547 static void smp_cross_call(const struct cpumask *target, unsigned int ipinr); 548 549 void show_ipi_list(struct seq_file *p, int prec) 550 { 551 unsigned int cpu, i; 552 553 for (i = 0; i < NR_IPI; i++) { 554 if (!ipi_desc[i]) 555 continue; 556 557 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i); 558 559 for_each_online_cpu(cpu) 560 seq_printf(p, "%10u ", irq_desc_kstat_cpu(ipi_desc[i], cpu)); 561 562 seq_printf(p, " %s\n", ipi_types[i]); 563 } 564 } 565 566 void arch_send_call_function_ipi_mask(const struct cpumask *mask) 567 { 568 smp_cross_call(mask, IPI_CALL_FUNC); 569 } 570 571 void arch_send_wakeup_ipi_mask(const struct cpumask *mask) 572 { 573 smp_cross_call(mask, IPI_WAKEUP); 574 } 575 576 void arch_send_call_function_single_ipi(int cpu) 577 { 578 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC); 579 } 580 581 #ifdef CONFIG_IRQ_WORK 582 void arch_irq_work_raise(void) 583 { 584 if (arch_irq_work_has_interrupt()) 585 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK); 586 } 587 #endif 588 589 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 590 void tick_broadcast(const struct cpumask *mask) 591 { 592 smp_cross_call(mask, IPI_TIMER); 593 } 594 #endif 595 596 static DEFINE_RAW_SPINLOCK(stop_lock); 597 598 /* 599 * ipi_cpu_stop - handle IPI from smp_send_stop() 600 */ 601 static void ipi_cpu_stop(unsigned int cpu) 602 { 603 if (system_state <= SYSTEM_RUNNING) { 604 raw_spin_lock(&stop_lock); 605 pr_crit("CPU%u: stopping\n", cpu); 606 dump_stack(); 607 raw_spin_unlock(&stop_lock); 608 } 609 610 set_cpu_online(cpu, false); 611 612 local_fiq_disable(); 613 local_irq_disable(); 614 615 while (1) { 616 cpu_relax(); 617 wfe(); 618 } 619 } 620 621 static DEFINE_PER_CPU(struct completion *, cpu_completion); 622 623 int register_ipi_completion(struct completion *completion, int cpu) 624 { 625 per_cpu(cpu_completion, cpu) = completion; 626 return IPI_COMPLETION; 627 } 628 629 static void ipi_complete(unsigned int cpu) 630 { 631 complete(per_cpu(cpu_completion, cpu)); 632 } 633 634 /* 635 * Main handler for inter-processor interrupts 636 */ 637 static void do_handle_IPI(int ipinr) 638 { 639 unsigned int cpu = smp_processor_id(); 640 641 if ((unsigned)ipinr < NR_IPI) 642 trace_ipi_entry_rcuidle(ipi_types[ipinr]); 643 644 switch (ipinr) { 645 case IPI_WAKEUP: 646 break; 647 648 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST 649 case IPI_TIMER: 650 tick_receive_broadcast(); 651 break; 652 #endif 653 654 case IPI_RESCHEDULE: 655 scheduler_ipi(); 656 break; 657 658 case IPI_CALL_FUNC: 659 generic_smp_call_function_interrupt(); 660 break; 661 662 case IPI_CPU_STOP: 663 ipi_cpu_stop(cpu); 664 break; 665 666 #ifdef CONFIG_IRQ_WORK 667 case IPI_IRQ_WORK: 668 irq_work_run(); 669 break; 670 #endif 671 672 case IPI_COMPLETION: 673 ipi_complete(cpu); 674 break; 675 676 case IPI_CPU_BACKTRACE: 677 printk_deferred_enter(); 678 nmi_cpu_backtrace(get_irq_regs()); 679 printk_deferred_exit(); 680 break; 681 682 default: 683 pr_crit("CPU%u: Unknown IPI message 0x%x\n", 684 cpu, ipinr); 685 break; 686 } 687 688 if ((unsigned)ipinr < NR_IPI) 689 trace_ipi_exit_rcuidle(ipi_types[ipinr]); 690 } 691 692 /* Legacy version, should go away once all irqchips have been converted */ 693 void handle_IPI(int ipinr, struct pt_regs *regs) 694 { 695 struct pt_regs *old_regs = set_irq_regs(regs); 696 697 irq_enter(); 698 do_handle_IPI(ipinr); 699 irq_exit(); 700 701 set_irq_regs(old_regs); 702 } 703 704 static irqreturn_t ipi_handler(int irq, void *data) 705 { 706 do_handle_IPI(irq - ipi_irq_base); 707 return IRQ_HANDLED; 708 } 709 710 static void smp_cross_call(const struct cpumask *target, unsigned int ipinr) 711 { 712 trace_ipi_raise_rcuidle(target, ipi_types[ipinr]); 713 __ipi_send_mask(ipi_desc[ipinr], target); 714 } 715 716 static void ipi_setup(int cpu) 717 { 718 int i; 719 720 if (WARN_ON_ONCE(!ipi_irq_base)) 721 return; 722 723 for (i = 0; i < nr_ipi; i++) 724 enable_percpu_irq(ipi_irq_base + i, 0); 725 } 726 727 void __init set_smp_ipi_range(int ipi_base, int n) 728 { 729 int i; 730 731 WARN_ON(n < MAX_IPI); 732 nr_ipi = min(n, MAX_IPI); 733 734 for (i = 0; i < nr_ipi; i++) { 735 int err; 736 737 err = request_percpu_irq(ipi_base + i, ipi_handler, 738 "IPI", &irq_stat); 739 WARN_ON(err); 740 741 ipi_desc[i] = irq_to_desc(ipi_base + i); 742 irq_set_status_flags(ipi_base + i, IRQ_HIDDEN); 743 } 744 745 ipi_irq_base = ipi_base; 746 747 /* Setup the boot CPU immediately */ 748 ipi_setup(smp_processor_id()); 749 } 750 751 void smp_send_reschedule(int cpu) 752 { 753 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); 754 } 755 756 void smp_send_stop(void) 757 { 758 unsigned long timeout; 759 struct cpumask mask; 760 761 cpumask_copy(&mask, cpu_online_mask); 762 cpumask_clear_cpu(smp_processor_id(), &mask); 763 if (!cpumask_empty(&mask)) 764 smp_cross_call(&mask, IPI_CPU_STOP); 765 766 /* Wait up to one second for other CPUs to stop */ 767 timeout = USEC_PER_SEC; 768 while (num_online_cpus() > 1 && timeout--) 769 udelay(1); 770 771 if (num_online_cpus() > 1) 772 pr_warn("SMP: failed to stop secondary CPUs\n"); 773 } 774 775 /* In case panic() and panic() called at the same time on CPU1 and CPU2, 776 * and CPU 1 calls panic_smp_self_stop() before crash_smp_send_stop() 777 * CPU1 can't receive the ipi irqs from CPU2, CPU1 will be always online, 778 * kdump fails. So split out the panic_smp_self_stop() and add 779 * set_cpu_online(smp_processor_id(), false). 780 */ 781 void panic_smp_self_stop(void) 782 { 783 pr_debug("CPU %u will stop doing anything useful since another CPU has paniced\n", 784 smp_processor_id()); 785 set_cpu_online(smp_processor_id(), false); 786 while (1) 787 cpu_relax(); 788 } 789 790 /* 791 * not supported here 792 */ 793 int setup_profiling_timer(unsigned int multiplier) 794 { 795 return -EINVAL; 796 } 797 798 #ifdef CONFIG_CPU_FREQ 799 800 static DEFINE_PER_CPU(unsigned long, l_p_j_ref); 801 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq); 802 static unsigned long global_l_p_j_ref; 803 static unsigned long global_l_p_j_ref_freq; 804 805 static int cpufreq_callback(struct notifier_block *nb, 806 unsigned long val, void *data) 807 { 808 struct cpufreq_freqs *freq = data; 809 struct cpumask *cpus = freq->policy->cpus; 810 int cpu, first = cpumask_first(cpus); 811 unsigned int lpj; 812 813 if (freq->flags & CPUFREQ_CONST_LOOPS) 814 return NOTIFY_OK; 815 816 if (!per_cpu(l_p_j_ref, first)) { 817 for_each_cpu(cpu, cpus) { 818 per_cpu(l_p_j_ref, cpu) = 819 per_cpu(cpu_data, cpu).loops_per_jiffy; 820 per_cpu(l_p_j_ref_freq, cpu) = freq->old; 821 } 822 823 if (!global_l_p_j_ref) { 824 global_l_p_j_ref = loops_per_jiffy; 825 global_l_p_j_ref_freq = freq->old; 826 } 827 } 828 829 if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) || 830 (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) { 831 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref, 832 global_l_p_j_ref_freq, 833 freq->new); 834 835 lpj = cpufreq_scale(per_cpu(l_p_j_ref, first), 836 per_cpu(l_p_j_ref_freq, first), freq->new); 837 for_each_cpu(cpu, cpus) 838 per_cpu(cpu_data, cpu).loops_per_jiffy = lpj; 839 } 840 return NOTIFY_OK; 841 } 842 843 static struct notifier_block cpufreq_notifier = { 844 .notifier_call = cpufreq_callback, 845 }; 846 847 static int __init register_cpufreq_notifier(void) 848 { 849 return cpufreq_register_notifier(&cpufreq_notifier, 850 CPUFREQ_TRANSITION_NOTIFIER); 851 } 852 core_initcall(register_cpufreq_notifier); 853 854 #endif 855 856 static void raise_nmi(cpumask_t *mask) 857 { 858 __ipi_send_mask(ipi_desc[IPI_CPU_BACKTRACE], mask); 859 } 860 861 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self) 862 { 863 nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_nmi); 864 } 865