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