arch/arm/kernel/smp.c

   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
  29 #include <linux/atomic.h>
  30 #include <asm/smp.h>
  31 #include <asm/cacheflush.h>
  32 #include <asm/cpu.h>
  33 #include <asm/cputype.h>
  34 #include <asm/exception.h>
  35 #include <asm/idmap.h>
  36 #include <asm/topology.h>
  37 #include <asm/mmu_context.h>
  38 #include <asm/pgtable.h>
  39 #include <asm/pgalloc.h>
  40 #include <asm/processor.h>
  41 #include <asm/sections.h>
  42 #include <asm/tlbflush.h>
  43 #include <asm/ptrace.h>
  44 #include <asm/localtimer.h>
  45 #include <asm/smp_plat.h>
  46 #include <asm/virt.h>
  47 #include <asm/mach/arch.h>
  48
  49 /*
  50  * as from 2.5, kernels no longer have an init_tasks structure
  51  * so we need some other way of telling a new secondary core
  52  * where to place its SVC stack
  53  */
  54 struct secondary_data secondary_data;
  55
  56 /*
  57  * control for which core is the next to come out of the secondary
  58  * boot "holding pen"
  59  */
  60 volatile int __cpuinitdata pen_release = -1;
  61
  62 enum ipi_msg_type {
  63         IPI_WAKEUP,
  64         IPI_TIMER,
  65         IPI_RESCHEDULE,
  66         IPI_CALL_FUNC,
  67         IPI_CALL_FUNC_SINGLE,
  68         IPI_CPU_STOP,
  69         IPI_CPU_BACKTRACE,
  70 };
  71
  72 static DECLARE_COMPLETION(cpu_running);
  73
  74 static struct smp_operations smp_ops;
  75
  76 void __init smp_set_ops(struct smp_operations *ops)
  77 {
  78         if (ops)
  79                 smp_ops = *ops;
  80 };
  81
  82 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
  83 {
  84         int ret;
  85
  86         /*
  87          * We need to tell the secondary core where to find
  88          * its stack and the page tables.
  89          */
  90         secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
  91         secondary_data.pgdir = virt_to_phys(idmap_pgd);
  92         secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir);
  93         __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
  94         outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
  95
  96         /*
  97          * Now bring the CPU into our world.
  98          */
  99         ret = boot_secondary(cpu, idle);
 100         if (ret == 0) {
 101                 /*
 102                  * CPU was successfully started, wait for it
 103                  * to come online or time out.
 104                  */
 105                 wait_for_completion_timeout(&cpu_running,
 106                                                  msecs_to_jiffies(1000));
 107
 108                 if (!cpu_online(cpu)) {
 109                         pr_crit("CPU%u: failed to come online\n", cpu);
 110                         ret = -EIO;
 111                 }
 112         } else {
 113                 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
 114         }
 115
 116         secondary_data.stack = NULL;
 117         secondary_data.pgdir = 0;
 118
 119         return ret;
 120 }
 121
 122 /* platform specific SMP operations */
 123 void __init smp_init_cpus(void)
 124 {
 125         if (smp_ops.smp_init_cpus)
 126                 smp_ops.smp_init_cpus();
 127 }
 128
 129 static void __init platform_smp_prepare_cpus(unsigned int max_cpus)
 130 {
 131         if (smp_ops.smp_prepare_cpus)
 132                 smp_ops.smp_prepare_cpus(max_cpus);
 133 }
 134
 135 static void __cpuinit platform_secondary_init(unsigned int cpu)
 136 {
 137         if (smp_ops.smp_secondary_init)
 138                 smp_ops.smp_secondary_init(cpu);
 139 }
 140
 141 int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
 142 {
 143         if (smp_ops.smp_boot_secondary)
 144                 return smp_ops.smp_boot_secondary(cpu, idle);
 145         return -ENOSYS;
 146 }
 147
 148 #ifdef CONFIG_HOTPLUG_CPU
 149 static void percpu_timer_stop(void);
 150
 151 static int platform_cpu_kill(unsigned int cpu)
 152 {
 153         if (smp_ops.cpu_kill)
 154                 return smp_ops.cpu_kill(cpu);
 155         return 1;
 156 }
 157
 158 static void platform_cpu_die(unsigned int cpu)
 159 {
 160         if (smp_ops.cpu_die)
 161                 smp_ops.cpu_die(cpu);
 162 }
 163
 164 static int platform_cpu_disable(unsigned int cpu)
 165 {
 166         if (smp_ops.cpu_disable)
 167                 return smp_ops.cpu_disable(cpu);
 168
 169         /*
 170          * By default, allow disabling all CPUs except the first one,
 171          * since this is special on a lot of platforms, e.g. because
 172          * of clock tick interrupts.
 173          */
 174         return cpu == 0 ? -EPERM : 0;
 175 }
 176 /*
 177  * __cpu_disable runs on the processor to be shutdown.
 178  */
 179 int __cpuinit __cpu_disable(void)
 180 {
 181         unsigned int cpu = smp_processor_id();
 182         int ret;
 183
 184         ret = platform_cpu_disable(cpu);
 185         if (ret)
 186                 return ret;
 187
 188         /*
 189          * Take this CPU offline.  Once we clear this, we can't return,
 190          * and we must not schedule until we're ready to give up the cpu.
 191          */
 192         set_cpu_online(cpu, false);
 193
 194         /*
 195          * OK - migrate IRQs away from this CPU
 196          */
 197         migrate_irqs();
 198
 199         /*
 200          * Stop the local timer for this CPU.
 201          */
 202         percpu_timer_stop();
 203
 204         /*
 205          * Flush user cache and TLB mappings, and then remove this CPU
 206          * from the vm mask set of all processes.
 207          *
 208          * Caches are flushed to the Level of Unification Inner Shareable
 209          * to write-back dirty lines to unified caches shared by all CPUs.
 210          */
 211         flush_cache_louis();
 212         local_flush_tlb_all();
 213
 214         clear_tasks_mm_cpumask(cpu);
 215
 216         return 0;
 217 }
 218
 219 static DECLARE_COMPLETION(cpu_died);
 220
 221 /*
 222  * called on the thread which is asking for a CPU to be shutdown -
 223  * waits until shutdown has completed, or it is timed out.
 224  */
 225 void __cpuinit __cpu_die(unsigned int cpu)
 226 {
 227         if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
 228                 pr_err("CPU%u: cpu didn't die\n", cpu);
 229                 return;
 230         }
 231         printk(KERN_NOTICE "CPU%u: shutdown\n", cpu);
 232
 233         if (!platform_cpu_kill(cpu))
 234                 printk("CPU%u: unable to kill\n", cpu);
 235 }
 236
 237 /*
 238  * Called from the idle thread for the CPU which has been shutdown.
 239  *
 240  * Note that we disable IRQs here, but do not re-enable them
 241  * before returning to the caller. This is also the behaviour
 242  * of the other hotplug-cpu capable cores, so presumably coming
 243  * out of idle fixes this.
 244  */
 245 void __ref cpu_die(void)
 246 {
 247         unsigned int cpu = smp_processor_id();
 248
 249         idle_task_exit();
 250
 251         local_irq_disable();
 252         mb();
 253
 254         /* Tell __cpu_die() that this CPU is now safe to dispose of */
 255         RCU_NONIDLE(complete(&cpu_died));
 256
 257         /*
 258          * actual CPU shutdown procedure is at least platform (if not
 259          * CPU) specific.
 260          */
 261         platform_cpu_die(cpu);
 262
 263         /*
 264          * Do not return to the idle loop - jump back to the secondary
 265          * cpu initialisation.  There's some initialisation which needs
 266          * to be repeated to undo the effects of taking the CPU offline.
 267          */
 268         __asm__("mov    sp, %0\n"
 269         "       mov     fp, #0\n"
 270         "       b       secondary_start_kernel"
 271                 :
 272                 : "r" (task_stack_page(current) + THREAD_SIZE - 8));
 273 }
 274 #endif /* CONFIG_HOTPLUG_CPU */
 275
 276 /*
 277  * Called by both boot and secondaries to move global data into
 278  * per-processor storage.
 279  */
 280 static void __cpuinit smp_store_cpu_info(unsigned int cpuid)
 281 {
 282         struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
 283
 284         cpu_info->loops_per_jiffy = loops_per_jiffy;
 285         cpu_info->cpuid = read_cpuid_id();
 286
 287         store_cpu_topology(cpuid);
 288 }
 289
 290 static void percpu_timer_setup(void);
 291
 292 /*
 293  * This is the secondary CPU boot entry.  We're using this CPUs
 294  * idle thread stack, but a set of temporary page tables.
 295  */
 296 asmlinkage void __cpuinit secondary_start_kernel(void)
 297 {
 298         struct mm_struct *mm = &init_mm;
 299         unsigned int cpu;
 300         static bool booted;
 301
 302         /*
 303          * The identity mapping is uncached (strongly ordered), so
 304          * switch away from it before attempting any exclusive accesses.
 305          */
 306         cpu_switch_mm(mm->pgd, mm);
 307         enter_lazy_tlb(mm, current);
 308         local_flush_tlb_all();
 309
 310         /*
 311          * All kernel threads share the same mm context; grab a
 312          * reference and switch to it.
 313          */
 314         cpu = smp_processor_id();
 315         atomic_inc(&mm->mm_count);
 316         current->active_mm = mm;
 317         cpumask_set_cpu(cpu, mm_cpumask(mm));
 318
 319         cpu_init();
 320
 321         printk("CPU%u: Booted secondary processor\n", cpu);
 322
 323         preempt_disable();
 324         trace_hardirqs_off();
 325
 326         /*
 327          * Give the platform a chance to do its own initialisation.
 328          */
 329         platform_secondary_init(cpu);
 330
 331         notify_cpu_starting(cpu);
 332
 333         if (!booted)
 334                 calibrate_delay();
 335         booted = true;
 336
 337         smp_store_cpu_info(cpu);
 338
 339         /*
 340          * OK, now it's safe to let the boot CPU continue.  Wait for
 341          * the CPU migration code to notice that the CPU is online
 342          * before we continue - which happens after __cpu_up returns.
 343          */
 344         set_cpu_online(cpu, true);
 345         complete(&cpu_running);
 346
 347         /*
 348          * Setup the percpu timer for this CPU.
 349          */
 350         percpu_timer_setup();
 351
 352         local_irq_enable();
 353         local_fiq_enable();
 354
 355         /*
 356          * OK, it's off to the idle thread for us
 357          */
 358         cpu_idle();
 359 }
 360
 361 void __init smp_cpus_done(unsigned int max_cpus)
 362 {
 363         int cpu;
 364         unsigned long bogosum = 0;
 365
 366         for_each_online_cpu(cpu)
 367                 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
 368
 369         printk(KERN_INFO "SMP: Total of %d processors activated "
 370                "(%lu.%02lu BogoMIPS).\n",
 371                num_online_cpus(),
 372                bogosum / (500000/HZ),
 373                (bogosum / (5000/HZ)) % 100);
 374
 375         hyp_mode_check();
 376 }
 377
 378 void __init smp_prepare_boot_cpu(void)
 379 {
 380         set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
 381 }
 382
 383 void __init smp_prepare_cpus(unsigned int max_cpus)
 384 {
 385         unsigned int ncores = num_possible_cpus();
 386
 387         init_cpu_topology();
 388
 389         smp_store_cpu_info(smp_processor_id());
 390
 391         /*
 392          * are we trying to boot more cores than exist?
 393          */
 394         if (max_cpus > ncores)
 395                 max_cpus = ncores;
 396         if (ncores > 1 && max_cpus) {
 397                 /*
 398                  * Enable the local timer or broadcast device for the
 399                  * boot CPU, but only if we have more than one CPU.
 400                  */
 401                 percpu_timer_setup();
 402
 403                 /*
 404                  * Initialise the present map, which describes the set of CPUs
 405                  * actually populated at the present time. A platform should
 406                  * re-initialize the map in platform_smp_prepare_cpus() if
 407                  * present != possible (e.g. physical hotplug).
 408                  */
 409                 init_cpu_present(cpu_possible_mask);
 410
 411                 /*
 412                  * Initialise the SCU if there are more than one CPU
 413                  * and let them know where to start.
 414                  */
 415                 platform_smp_prepare_cpus(max_cpus);
 416         }
 417 }
 418
 419 static void (*smp_cross_call)(const struct cpumask *, unsigned int);
 420
 421 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
 422 {
 423         smp_cross_call = fn;
 424 }
 425
 426 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 427 {
 428         smp_cross_call(mask, IPI_CALL_FUNC);
 429 }
 430
 431 void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
 432 {
 433         smp_cross_call(mask, IPI_WAKEUP);
 434 }
 435
 436 void arch_send_call_function_single_ipi(int cpu)
 437 {
 438         smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
 439 }
 440
 441 static const char *ipi_types[NR_IPI] = {
 442 #define S(x,s)  [x] = s
 443         S(IPI_WAKEUP, "CPU wakeup interrupts"),
 444         S(IPI_TIMER, "Timer broadcast interrupts"),
 445         S(IPI_RESCHEDULE, "Rescheduling interrupts"),
 446         S(IPI_CALL_FUNC, "Function call interrupts"),
 447         S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
 448         S(IPI_CPU_STOP, "CPU stop interrupts"),
 449         S(IPI_CPU_BACKTRACE, "CPU backtrace"),
 450 };
 451
 452 void show_ipi_list(struct seq_file *p, int prec)
 453 {
 454         unsigned int cpu, i;
 455
 456         for (i = 0; i < NR_IPI; i++) {
 457                 seq_printf(p, "%*s%u: ", prec - 1, "IPI", i);
 458
 459                 for_each_online_cpu(cpu)
 460                         seq_printf(p, "%10u ",
 461                                    __get_irq_stat(cpu, ipi_irqs[i]));
 462
 463                 seq_printf(p, " %s\n", ipi_types[i]);
 464         }
 465 }
 466
 467 u64 smp_irq_stat_cpu(unsigned int cpu)
 468 {
 469         u64 sum = 0;
 470         int i;
 471
 472         for (i = 0; i < NR_IPI; i++)
 473                 sum += __get_irq_stat(cpu, ipi_irqs[i]);
 474
 475         return sum;
 476 }
 477
 478 /*
 479  * Timer (local or broadcast) support
 480  */
 481 static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent);
 482
 483 static void ipi_timer(void)
 484 {
 485         struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent);
 486         evt->event_handler(evt);
 487 }
 488
 489 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 490 static void smp_timer_broadcast(const struct cpumask *mask)
 491 {
 492         smp_cross_call(mask, IPI_TIMER);
 493 }
 494 #else
 495 #define smp_timer_broadcast     NULL
 496 #endif
 497
 498 static void broadcast_timer_set_mode(enum clock_event_mode mode,
 499         struct clock_event_device *evt)
 500 {
 501 }
 502
 503 static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
 504 {
 505         evt->name       = "dummy_timer";
 506         evt->features   = CLOCK_EVT_FEAT_ONESHOT |
 507                           CLOCK_EVT_FEAT_PERIODIC |
 508                           CLOCK_EVT_FEAT_DUMMY;
 509         evt->rating     = 400;
 510         evt->mult       = 1;
 511         evt->set_mode   = broadcast_timer_set_mode;
 512
 513         clockevents_register_device(evt);
 514 }
 515
 516 static struct local_timer_ops *lt_ops;
 517
 518 #ifdef CONFIG_LOCAL_TIMERS
 519 int local_timer_register(struct local_timer_ops *ops)
 520 {
 521         if (!is_smp() || !setup_max_cpus)
 522                 return -ENXIO;
 523
 524         if (lt_ops)
 525                 return -EBUSY;
 526
 527         lt_ops = ops;
 528         return 0;
 529 }
 530 #endif
 531
 532 static void __cpuinit percpu_timer_setup(void)
 533 {
 534         unsigned int cpu = smp_processor_id();
 535         struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
 536
 537         evt->cpumask = cpumask_of(cpu);
 538         evt->broadcast = smp_timer_broadcast;
 539
 540         if (!lt_ops || lt_ops->setup(evt))
 541                 broadcast_timer_setup(evt);
 542 }
 543
 544 #ifdef CONFIG_HOTPLUG_CPU
 545 /*
 546  * The generic clock events code purposely does not stop the local timer
 547  * on CPU_DEAD/CPU_DEAD_FROZEN hotplug events, so we have to do it
 548  * manually here.
 549  */
 550 static void percpu_timer_stop(void)
 551 {
 552         unsigned int cpu = smp_processor_id();
 553         struct clock_event_device *evt = &per_cpu(percpu_clockevent, cpu);
 554
 555         if (lt_ops)
 556                 lt_ops->stop(evt);
 557 }
 558 #endif
 559
 560 static DEFINE_RAW_SPINLOCK(stop_lock);
 561
 562 /*
 563  * ipi_cpu_stop - handle IPI from smp_send_stop()
 564  */
 565 static void ipi_cpu_stop(unsigned int cpu)
 566 {
 567         if (system_state == SYSTEM_BOOTING ||
 568             system_state == SYSTEM_RUNNING) {
 569                 raw_spin_lock(&stop_lock);
 570                 printk(KERN_CRIT "CPU%u: stopping\n", cpu);
 571                 dump_stack();
 572                 raw_spin_unlock(&stop_lock);
 573         }
 574
 575         set_cpu_online(cpu, false);
 576
 577         local_fiq_disable();
 578         local_irq_disable();
 579
 580         while (1)
 581                 cpu_relax();
 582 }
 583
 584 static cpumask_t backtrace_mask;
 585 static DEFINE_RAW_SPINLOCK(backtrace_lock);
 586
 587 /* "in progress" flag of arch_trigger_all_cpu_backtrace */
 588 static unsigned long backtrace_flag;
 589
 590 void smp_send_all_cpu_backtrace(void)
 591 {
 592         unsigned int this_cpu = smp_processor_id();
 593         int i;
 594
 595         if (test_and_set_bit(0, &backtrace_flag))
 596                 /*
 597                  * If there is already a trigger_all_cpu_backtrace() in progress
 598                  * (backtrace_flag == 1), don't output double cpu dump infos.
 599                  */
 600                 return;
 601
 602         cpumask_copy(&backtrace_mask, cpu_online_mask);
 603         cpu_clear(this_cpu, backtrace_mask);
 604
 605         pr_info("Backtrace for cpu %d (current):\n", this_cpu);
 606         dump_stack();
 607
 608         pr_info("\nsending IPI to all other CPUs:\n");
 609         smp_cross_call(&backtrace_mask, IPI_CPU_BACKTRACE);
 610
 611         /* Wait for up to 10 seconds for all other CPUs to do the backtrace */
 612         for (i = 0; i < 10 * 1000; i++) {
 613                 if (cpumask_empty(&backtrace_mask))
 614                         break;
 615                 mdelay(1);
 616         }
 617
 618         clear_bit(0, &backtrace_flag);
 619         smp_mb__after_clear_bit();
 620 }
 621
 622 /*
 623  * ipi_cpu_backtrace - handle IPI from smp_send_all_cpu_backtrace()
 624  */
 625 static void ipi_cpu_backtrace(unsigned int cpu, struct pt_regs *regs)
 626 {
 627         if (cpu_isset(cpu, backtrace_mask)) {
 628                 raw_spin_lock(&backtrace_lock);
 629                 pr_warning("IPI backtrace for cpu %d\n", cpu);
 630                 show_regs(regs);
 631                 raw_spin_unlock(&backtrace_lock);
 632                 cpu_clear(cpu, backtrace_mask);
 633         }
 634 }
 635
 636 /*
 637  * Main handler for inter-processor interrupts
 638  */
 639 asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
 640 {
 641         handle_IPI(ipinr, regs);
 642 }
 643
 644 void handle_IPI(int ipinr, struct pt_regs *regs)
 645 {
 646         unsigned int cpu = smp_processor_id();
 647         struct pt_regs *old_regs = set_irq_regs(regs);
 648
 649         if (ipinr < NR_IPI)
 650                 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
 651
 652         switch (ipinr) {
 653         case IPI_WAKEUP:
 654                 break;
 655
 656         case IPI_TIMER:
 657                 irq_enter();
 658                 ipi_timer();
 659                 irq_exit();
 660                 break;
 661
 662         case IPI_RESCHEDULE:
 663                 scheduler_ipi();
 664                 break;
 665
 666         case IPI_CALL_FUNC:
 667                 irq_enter();
 668                 generic_smp_call_function_interrupt();
 669                 irq_exit();
 670                 break;
 671
 672         case IPI_CALL_FUNC_SINGLE:
 673                 irq_enter();
 674                 generic_smp_call_function_single_interrupt();
 675                 irq_exit();
 676                 break;
 677
 678         case IPI_CPU_STOP:
 679                 irq_enter();
 680                 ipi_cpu_stop(cpu);
 681                 irq_exit();
 682                 break;
 683
 684         case IPI_CPU_BACKTRACE:
 685                 ipi_cpu_backtrace(cpu, regs);
 686                 break;
 687
 688         default:
 689                 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
 690                        cpu, ipinr);
 691                 break;
 692         }
 693         set_irq_regs(old_regs);
 694 }
 695
 696 void smp_send_reschedule(int cpu)
 697 {
 698         smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 699 }
 700
 701 #ifdef CONFIG_HOTPLUG_CPU
 702 static void smp_kill_cpus(cpumask_t *mask)
 703 {
 704         unsigned int cpu;
 705         for_each_cpu(cpu, mask)
 706                 platform_cpu_kill(cpu);
 707 }
 708 #else
 709 static void smp_kill_cpus(cpumask_t *mask) { }
 710 #endif
 711
 712 void smp_send_stop(void)
 713 {
 714         unsigned long timeout;
 715         struct cpumask mask;
 716
 717         cpumask_copy(&mask, cpu_online_mask);
 718         cpumask_clear_cpu(smp_processor_id(), &mask);
 719         if (!cpumask_empty(&mask))
 720                 smp_cross_call(&mask, IPI_CPU_STOP);
 721
 722         /* Wait up to one second for other CPUs to stop */
 723         timeout = USEC_PER_SEC;
 724         while (num_online_cpus() > 1 && timeout--)
 725                 udelay(1);
 726
 727         if (num_online_cpus() > 1)
 728                 pr_warning("SMP: failed to stop secondary CPUs\n");
 729
 730         smp_kill_cpus(&mask);
 731 }
 732
 733 /*
 734  * not supported here
 735  */
 736 int setup_profiling_timer(unsigned int multiplier)
 737 {
 738         return -EINVAL;
 739 }
 740
 741 #ifdef CONFIG_CPU_FREQ
 742
 743 static DEFINE_PER_CPU(unsigned long, l_p_j_ref);
 744 static DEFINE_PER_CPU(unsigned long, l_p_j_ref_freq);
 745 static unsigned long global_l_p_j_ref;
 746 static unsigned long global_l_p_j_ref_freq;
 747
 748 static int cpufreq_callback(struct notifier_block *nb,
 749                                         unsigned long val, void *data)
 750 {
 751         struct cpufreq_freqs *freq = data;
 752         int cpu = freq->cpu;
 753
 754         if (freq->flags & CPUFREQ_CONST_LOOPS)
 755                 return NOTIFY_OK;
 756
 757         if (arm_delay_ops.const_clock)
 758                 return NOTIFY_OK;
 759
 760         if (!per_cpu(l_p_j_ref, cpu)) {
 761                 per_cpu(l_p_j_ref, cpu) =
 762                         per_cpu(cpu_data, cpu).loops_per_jiffy;
 763                 per_cpu(l_p_j_ref_freq, cpu) = freq->old;
 764                 if (!global_l_p_j_ref) {
 765                         global_l_p_j_ref = loops_per_jiffy;
 766                         global_l_p_j_ref_freq = freq->old;
 767                 }
 768         }
 769
 770         if ((val == CPUFREQ_PRECHANGE  && freq->old < freq->new) ||
 771             (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
 772             (val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
 773                 loops_per_jiffy = cpufreq_scale(global_l_p_j_ref,
 774                                                 global_l_p_j_ref_freq,
 775                                                 freq->new);
 776                 per_cpu(cpu_data, cpu).loops_per_jiffy =
 777                         cpufreq_scale(per_cpu(l_p_j_ref, cpu),
 778                                         per_cpu(l_p_j_ref_freq, cpu),
 779                                         freq->new);
 780         }
 781         return NOTIFY_OK;
 782 }
 783
 784 static struct notifier_block cpufreq_notifier = {
 785         .notifier_call  = cpufreq_callback,
 786 };
 787
 788 static int __init register_cpufreq_notifier(void)
 789 {
 790         return cpufreq_register_notifier(&cpufreq_notifier,
 791                                                 CPUFREQ_TRANSITION_NOTIFIER);
 792 }
 793 core_initcall(register_cpufreq_notifier);
 794
 795 #endif