arch/powerpc/kernel/smp.c

   1 /*
   2  * SMP support for ppc.
   3  *
   4  * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great
   5  * deal of code from the sparc and intel versions.
   6  *
   7  * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
   8  *
   9  * PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and
  10  * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  */
  17
  18 #undef DEBUG
  19
  20 #include <linux/kernel.h>
  21 #include <linux/export.h>
  22 #include <linux/sched.h>
  23 #include <linux/smp.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/delay.h>
  26 #include <linux/init.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/cache.h>
  29 #include <linux/err.h>
  30 #include <linux/sysdev.h>
  31 #include <linux/cpu.h>
  32 #include <linux/notifier.h>
  33 #include <linux/topology.h>
  34
  35 #include <asm/ptrace.h>
  36 #include <linux/atomic.h>
  37 #include <asm/irq.h>
  38 #include <asm/page.h>
  39 #include <asm/pgtable.h>
  40 #include <asm/prom.h>
  41 #include <asm/smp.h>
  42 #include <asm/time.h>
  43 #include <asm/machdep.h>
  44 #include <asm/cputhreads.h>
  45 #include <asm/cputable.h>
  46 #include <asm/system.h>
  47 #include <asm/mpic.h>
  48 #include <asm/vdso_datapage.h>
  49 #ifdef CONFIG_PPC64
  50 #include <asm/paca.h>
  51 #endif
  52
  53 #ifdef DEBUG
  54 #include <asm/udbg.h>
  55 #define DBG(fmt...) udbg_printf(fmt)
  56 #else
  57 #define DBG(fmt...)
  58 #endif
  59
  60
  61 /* Store all idle threads, this can be reused instead of creating
  62 * a new thread. Also avoids complicated thread destroy functionality
  63 * for idle threads.
  64 */
  65 #ifdef CONFIG_HOTPLUG_CPU
  66 /*
  67  * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
  68  * removed after init for !CONFIG_HOTPLUG_CPU.
  69  */
  70 static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
  71 #define get_idle_for_cpu(x)      (per_cpu(idle_thread_array, x))
  72 #define set_idle_for_cpu(x, p)   (per_cpu(idle_thread_array, x) = (p))
  73
  74 /* State of each CPU during hotplug phases */
  75 static DEFINE_PER_CPU(int, cpu_state) = { 0 };
  76
  77 #else
  78 static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
  79 #define get_idle_for_cpu(x)      (idle_thread_array[(x)])
  80 #define set_idle_for_cpu(x, p)   (idle_thread_array[(x)] = (p))
  81 #endif
  82
  83 struct thread_info *secondary_ti;
  84
  85 DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
  86 DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
  87
  88 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
  89 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
  90
  91 /* SMP operations for this machine */
  92 struct smp_ops_t *smp_ops;
  93
  94 /* Can't be static due to PowerMac hackery */
  95 volatile unsigned int cpu_callin_map[NR_CPUS];
  96
  97 int smt_enabled_at_boot = 1;
  98
  99 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
 100
 101 #ifdef CONFIG_PPC64
 102 int __devinit smp_generic_kick_cpu(int nr)
 103 {
 104         BUG_ON(nr < 0 || nr >= NR_CPUS);
 105
 106         /*
 107          * The processor is currently spinning, waiting for the
 108          * cpu_start field to become non-zero After we set cpu_start,
 109          * the processor will continue on to secondary_start
 110          */
 111         if (!paca[nr].cpu_start) {
 112                 paca[nr].cpu_start = 1;
 113                 smp_mb();
 114                 return 0;
 115         }
 116
 117 #ifdef CONFIG_HOTPLUG_CPU
 118         /*
 119          * Ok it's not there, so it might be soft-unplugged, let's
 120          * try to bring it back
 121          */
 122         per_cpu(cpu_state, nr) = CPU_UP_PREPARE;
 123         smp_wmb();
 124         smp_send_reschedule(nr);
 125 #endif /* CONFIG_HOTPLUG_CPU */
 126
 127         return 0;
 128 }
 129 #endif /* CONFIG_PPC64 */
 130
 131 static irqreturn_t call_function_action(int irq, void *data)
 132 {
 133         generic_smp_call_function_interrupt();
 134         return IRQ_HANDLED;
 135 }
 136
 137 static irqreturn_t reschedule_action(int irq, void *data)
 138 {
 139         scheduler_ipi();
 140         return IRQ_HANDLED;
 141 }
 142
 143 static irqreturn_t call_function_single_action(int irq, void *data)
 144 {
 145         generic_smp_call_function_single_interrupt();
 146         return IRQ_HANDLED;
 147 }
 148
 149 static irqreturn_t debug_ipi_action(int irq, void *data)
 150 {
 151         if (crash_ipi_function_ptr) {
 152                 crash_ipi_function_ptr(get_irq_regs());
 153                 return IRQ_HANDLED;
 154         }
 155
 156 #ifdef CONFIG_DEBUGGER
 157         debugger_ipi(get_irq_regs());
 158 #endif /* CONFIG_DEBUGGER */
 159
 160         return IRQ_HANDLED;
 161 }
 162
 163 static irq_handler_t smp_ipi_action[] = {
 164         [PPC_MSG_CALL_FUNCTION] =  call_function_action,
 165         [PPC_MSG_RESCHEDULE] = reschedule_action,
 166         [PPC_MSG_CALL_FUNC_SINGLE] = call_function_single_action,
 167         [PPC_MSG_DEBUGGER_BREAK] = debug_ipi_action,
 168 };
 169
 170 const char *smp_ipi_name[] = {
 171         [PPC_MSG_CALL_FUNCTION] =  "ipi call function",
 172         [PPC_MSG_RESCHEDULE] = "ipi reschedule",
 173         [PPC_MSG_CALL_FUNC_SINGLE] = "ipi call function single",
 174         [PPC_MSG_DEBUGGER_BREAK] = "ipi debugger",
 175 };
 176
 177 /* optional function to request ipi, for controllers with >= 4 ipis */
 178 int smp_request_message_ipi(int virq, int msg)
 179 {
 180         int err;
 181
 182         if (msg < 0 || msg > PPC_MSG_DEBUGGER_BREAK) {
 183                 return -EINVAL;
 184         }
 185 #if !defined(CONFIG_DEBUGGER) && !defined(CONFIG_KEXEC)
 186         if (msg == PPC_MSG_DEBUGGER_BREAK) {
 187                 return 1;
 188         }
 189 #endif
 190         err = request_irq(virq, smp_ipi_action[msg], IRQF_DISABLED|IRQF_PERCPU,
 191                           smp_ipi_name[msg], 0);
 192         WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n",
 193                 virq, smp_ipi_name[msg], err);
 194
 195         return err;
 196 }
 197
 198 #ifdef CONFIG_PPC_SMP_MUXED_IPI
 199 struct cpu_messages {
 200         int messages;                   /* current messages */
 201         unsigned long data;             /* data for cause ipi */
 202 };
 203 static DEFINE_PER_CPU_SHARED_ALIGNED(struct cpu_messages, ipi_message);
 204
 205 void smp_muxed_ipi_set_data(int cpu, unsigned long data)
 206 {
 207         struct cpu_messages *info = &per_cpu(ipi_message, cpu);
 208
 209         info->data = data;
 210 }
 211
 212 void smp_muxed_ipi_message_pass(int cpu, int msg)
 213 {
 214         struct cpu_messages *info = &per_cpu(ipi_message, cpu);
 215         char *message = (char *)&info->messages;
 216
 217         message[msg] = 1;
 218         mb();
 219         smp_ops->cause_ipi(cpu, info->data);
 220 }
 221
 222 irqreturn_t smp_ipi_demux(void)
 223 {
 224         struct cpu_messages *info = &__get_cpu_var(ipi_message);
 225         unsigned int all;
 226
 227         mb();   /* order any irq clear */
 228
 229         do {
 230                 all = xchg_local(&info->messages, 0);
 231
 232 #ifdef __BIG_ENDIAN
 233                 if (all & (1 << (24 - 8 * PPC_MSG_CALL_FUNCTION)))
 234                         generic_smp_call_function_interrupt();
 235                 if (all & (1 << (24 - 8 * PPC_MSG_RESCHEDULE)))
 236                         scheduler_ipi();
 237                 if (all & (1 << (24 - 8 * PPC_MSG_CALL_FUNC_SINGLE)))
 238                         generic_smp_call_function_single_interrupt();
 239                 if (all & (1 << (24 - 8 * PPC_MSG_DEBUGGER_BREAK)))
 240                         debug_ipi_action(0, NULL);
 241 #else
 242 #error Unsupported ENDIAN
 243 #endif
 244         } while (info->messages);
 245
 246         return IRQ_HANDLED;
 247 }
 248 #endif /* CONFIG_PPC_SMP_MUXED_IPI */
 249
 250 static inline void do_message_pass(int cpu, int msg)
 251 {
 252         if (smp_ops->message_pass)
 253                 smp_ops->message_pass(cpu, msg);
 254 #ifdef CONFIG_PPC_SMP_MUXED_IPI
 255         else
 256                 smp_muxed_ipi_message_pass(cpu, msg);
 257 #endif
 258 }
 259
 260 void smp_send_reschedule(int cpu)
 261 {
 262         if (likely(smp_ops))
 263                 do_message_pass(cpu, PPC_MSG_RESCHEDULE);
 264 }
 265 EXPORT_SYMBOL_GPL(smp_send_reschedule);
 266
 267 void arch_send_call_function_single_ipi(int cpu)
 268 {
 269         do_message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
 270 }
 271
 272 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 273 {
 274         unsigned int cpu;
 275
 276         for_each_cpu(cpu, mask)
 277                 do_message_pass(cpu, PPC_MSG_CALL_FUNCTION);
 278 }
 279
 280 #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
 281 void smp_send_debugger_break(void)
 282 {
 283         int cpu;
 284         int me = raw_smp_processor_id();
 285
 286         if (unlikely(!smp_ops))
 287                 return;
 288
 289         for_each_online_cpu(cpu)
 290                 if (cpu != me)
 291                         do_message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 292 }
 293 #endif
 294
 295 #ifdef CONFIG_KEXEC
 296 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 297 {
 298         crash_ipi_function_ptr = crash_ipi_callback;
 299         if (crash_ipi_callback) {
 300                 mb();
 301                 smp_send_debugger_break();
 302         }
 303 }
 304 #endif
 305
 306 static void stop_this_cpu(void *dummy)
 307 {
 308         /* Remove this CPU */
 309         set_cpu_online(smp_processor_id(), false);
 310
 311         local_irq_disable();
 312         while (1)
 313                 ;
 314 }
 315
 316 void smp_send_stop(void)
 317 {
 318         smp_call_function(stop_this_cpu, NULL, 0);
 319 }
 320
 321 struct thread_info *current_set[NR_CPUS];
 322
 323 static void __devinit smp_store_cpu_info(int id)
 324 {
 325         per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR);
 326 #ifdef CONFIG_PPC_FSL_BOOK3E
 327         per_cpu(next_tlbcam_idx, id)
 328                 = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) - 1;
 329 #endif
 330 }
 331
 332 void __init smp_prepare_cpus(unsigned int max_cpus)
 333 {
 334         unsigned int cpu;
 335
 336         DBG("smp_prepare_cpus\n");
 337
 338         /*
 339          * setup_cpu may need to be called on the boot cpu. We havent
 340          * spun any cpus up but lets be paranoid.
 341          */
 342         BUG_ON(boot_cpuid != smp_processor_id());
 343
 344         /* Fixup boot cpu */
 345         smp_store_cpu_info(boot_cpuid);
 346         cpu_callin_map[boot_cpuid] = 1;
 347
 348         for_each_possible_cpu(cpu) {
 349                 zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu),
 350                                         GFP_KERNEL, cpu_to_node(cpu));
 351                 zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
 352                                         GFP_KERNEL, cpu_to_node(cpu));
 353         }
 354
 355         cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid));
 356         cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
 357
 358         if (smp_ops)
 359                 if (smp_ops->probe)
 360                         max_cpus = smp_ops->probe();
 361                 else
 362                         max_cpus = NR_CPUS;
 363         else
 364                 max_cpus = 1;
 365 }
 366
 367 void __devinit smp_prepare_boot_cpu(void)
 368 {
 369         BUG_ON(smp_processor_id() != boot_cpuid);
 370 #ifdef CONFIG_PPC64
 371         paca[boot_cpuid].__current = current;
 372 #endif
 373         current_set[boot_cpuid] = task_thread_info(current);
 374 }
 375
 376 #ifdef CONFIG_HOTPLUG_CPU
 377
 378 int generic_cpu_disable(void)
 379 {
 380         unsigned int cpu = smp_processor_id();
 381
 382         if (cpu == boot_cpuid)
 383                 return -EBUSY;
 384
 385         set_cpu_online(cpu, false);
 386 #ifdef CONFIG_PPC64
 387         vdso_data->processorCount--;
 388 #endif
 389         migrate_irqs();
 390         return 0;
 391 }
 392
 393 void generic_cpu_die(unsigned int cpu)
 394 {
 395         int i;
 396
 397         for (i = 0; i < 100; i++) {
 398                 smp_rmb();
 399                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 400                         return;
 401                 msleep(100);
 402         }
 403         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 404 }
 405
 406 void generic_mach_cpu_die(void)
 407 {
 408         unsigned int cpu;
 409
 410         local_irq_disable();
 411         idle_task_exit();
 412         cpu = smp_processor_id();
 413         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 414         __get_cpu_var(cpu_state) = CPU_DEAD;
 415         smp_wmb();
 416         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 417                 cpu_relax();
 418 }
 419
 420 void generic_set_cpu_dead(unsigned int cpu)
 421 {
 422         per_cpu(cpu_state, cpu) = CPU_DEAD;
 423 }
 424
 425 int generic_check_cpu_restart(unsigned int cpu)
 426 {
 427         return per_cpu(cpu_state, cpu) == CPU_UP_PREPARE;
 428 }
 429 #endif
 430
 431 struct create_idle {
 432         struct work_struct work;
 433         struct task_struct *idle;
 434         struct completion done;
 435         int cpu;
 436 };
 437
 438 static void __cpuinit do_fork_idle(struct work_struct *work)
 439 {
 440         struct create_idle *c_idle =
 441                 container_of(work, struct create_idle, work);
 442
 443         c_idle->idle = fork_idle(c_idle->cpu);
 444         complete(&c_idle->done);
 445 }
 446
 447 static int __cpuinit create_idle(unsigned int cpu)
 448 {
 449         struct thread_info *ti;
 450         struct create_idle c_idle = {
 451                 .cpu    = cpu,
 452                 .done   = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
 453         };
 454         INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
 455
 456         c_idle.idle = get_idle_for_cpu(cpu);
 457
 458         /* We can't use kernel_thread since we must avoid to
 459          * reschedule the child. We use a workqueue because
 460          * we want to fork from a kernel thread, not whatever
 461          * userspace process happens to be trying to online us.
 462          */
 463         if (!c_idle.idle) {
 464                 schedule_work(&c_idle.work);
 465                 wait_for_completion(&c_idle.done);
 466         } else
 467                 init_idle(c_idle.idle, cpu);
 468         if (IS_ERR(c_idle.idle)) {
 469                 pr_err("Failed fork for CPU %u: %li", cpu, PTR_ERR(c_idle.idle));
 470                 return PTR_ERR(c_idle.idle);
 471         }
 472         ti = task_thread_info(c_idle.idle);
 473
 474 #ifdef CONFIG_PPC64
 475         paca[cpu].__current = c_idle.idle;
 476         paca[cpu].kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD;
 477 #endif
 478         ti->cpu = cpu;
 479         current_set[cpu] = ti;
 480
 481         return 0;
 482 }
 483
 484 int __cpuinit __cpu_up(unsigned int cpu)
 485 {
 486         int rc, c;
 487
 488         if (smp_ops == NULL ||
 489             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 490                 return -EINVAL;
 491
 492         /* Make sure we have an idle thread */
 493         rc = create_idle(cpu);
 494         if (rc)
 495                 return rc;
 496
 497         secondary_ti = current_set[cpu];
 498
 499         /* Make sure callin-map entry is 0 (can be leftover a CPU
 500          * hotplug
 501          */
 502         cpu_callin_map[cpu] = 0;
 503
 504         /* The information for processor bringup must
 505          * be written out to main store before we release
 506          * the processor.
 507          */
 508         smp_mb();
 509
 510         /* wake up cpus */
 511         DBG("smp: kicking cpu %d\n", cpu);
 512         rc = smp_ops->kick_cpu(cpu);
 513         if (rc) {
 514                 pr_err("smp: failed starting cpu %d (rc %d)\n", cpu, rc);
 515                 return rc;
 516         }
 517
 518         /*
 519          * wait to see if the cpu made a callin (is actually up).
 520          * use this value that I found through experimentation.
 521          * -- Cort
 522          */
 523         if (system_state < SYSTEM_RUNNING)
 524                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
 525                         udelay(100);
 526 #ifdef CONFIG_HOTPLUG_CPU
 527         else
 528                 /*
 529                  * CPUs can take much longer to come up in the
 530                  * hotplug case.  Wait five seconds.
 531                  */
 532                 for (c = 5000; c && !cpu_callin_map[cpu]; c--)
 533                         msleep(1);
 534 #endif
 535
 536         if (!cpu_callin_map[cpu]) {
 537                 printk(KERN_ERR "Processor %u is stuck.\n", cpu);
 538                 return -ENOENT;
 539         }
 540
 541         DBG("Processor %u found.\n", cpu);
 542
 543         if (smp_ops->give_timebase)
 544                 smp_ops->give_timebase();
 545
 546         /* Wait until cpu puts itself in the online map */
 547         while (!cpu_online(cpu))
 548                 cpu_relax();
 549
 550         return 0;
 551 }
 552
 553 /* Return the value of the reg property corresponding to the given
 554  * logical cpu.
 555  */
 556 int cpu_to_core_id(int cpu)
 557 {
 558         struct device_node *np;
 559         const int *reg;
 560         int id = -1;
 561
 562         np = of_get_cpu_node(cpu, NULL);
 563         if (!np)
 564                 goto out;
 565
 566         reg = of_get_property(np, "reg", NULL);
 567         if (!reg)
 568                 goto out;
 569
 570         id = *reg;
 571 out:
 572         of_node_put(np);
 573         return id;
 574 }
 575
 576 /* Helper routines for cpu to core mapping */
 577 int cpu_core_index_of_thread(int cpu)
 578 {
 579         return cpu >> threads_shift;
 580 }
 581 EXPORT_SYMBOL_GPL(cpu_core_index_of_thread);
 582
 583 int cpu_first_thread_of_core(int core)
 584 {
 585         return core << threads_shift;
 586 }
 587 EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);
 588
 589 /* Must be called when no change can occur to cpu_present_mask,
 590  * i.e. during cpu online or offline.
 591  */
 592 static struct device_node *cpu_to_l2cache(int cpu)
 593 {
 594         struct device_node *np;
 595         struct device_node *cache;
 596
 597         if (!cpu_present(cpu))
 598                 return NULL;
 599
 600         np = of_get_cpu_node(cpu, NULL);
 601         if (np == NULL)
 602                 return NULL;
 603
 604         cache = of_find_next_cache_node(np);
 605
 606         of_node_put(np);
 607
 608         return cache;
 609 }
 610
 611 /* Activate a secondary processor. */
 612 void __devinit start_secondary(void *unused)
 613 {
 614         unsigned int cpu = smp_processor_id();
 615         struct device_node *l2_cache;
 616         int i, base;
 617
 618         atomic_inc(&init_mm.mm_count);
 619         current->active_mm = &init_mm;
 620
 621         smp_store_cpu_info(cpu);
 622         set_dec(tb_ticks_per_jiffy);
 623         preempt_disable();
 624         cpu_callin_map[cpu] = 1;
 625
 626         if (smp_ops->setup_cpu)
 627                 smp_ops->setup_cpu(cpu);
 628         if (smp_ops->take_timebase)
 629                 smp_ops->take_timebase();
 630
 631         secondary_cpu_time_init();
 632
 633 #ifdef CONFIG_PPC64
 634         if (system_state == SYSTEM_RUNNING)
 635                 vdso_data->processorCount++;
 636 #endif
 637         ipi_call_lock();
 638         notify_cpu_starting(cpu);
 639         set_cpu_online(cpu, true);
 640         /* Update sibling maps */
 641         base = cpu_first_thread_sibling(cpu);
 642         for (i = 0; i < threads_per_core; i++) {
 643                 if (cpu_is_offline(base + i))
 644                         continue;
 645                 cpumask_set_cpu(cpu, cpu_sibling_mask(base + i));
 646                 cpumask_set_cpu(base + i, cpu_sibling_mask(cpu));
 647
 648                 /* cpu_core_map should be a superset of
 649                  * cpu_sibling_map even if we don't have cache
 650                  * information, so update the former here, too.
 651                  */
 652                 cpumask_set_cpu(cpu, cpu_core_mask(base + i));
 653                 cpumask_set_cpu(base + i, cpu_core_mask(cpu));
 654         }
 655         l2_cache = cpu_to_l2cache(cpu);
 656         for_each_online_cpu(i) {
 657                 struct device_node *np = cpu_to_l2cache(i);
 658                 if (!np)
 659                         continue;
 660                 if (np == l2_cache) {
 661                         cpumask_set_cpu(cpu, cpu_core_mask(i));
 662                         cpumask_set_cpu(i, cpu_core_mask(cpu));
 663                 }
 664                 of_node_put(np);
 665         }
 666         of_node_put(l2_cache);
 667         ipi_call_unlock();
 668
 669         local_irq_enable();
 670
 671         cpu_idle();
 672
 673         BUG();
 674 }
 675
 676 int setup_profiling_timer(unsigned int multiplier)
 677 {
 678         return 0;
 679 }
 680
 681 void __init smp_cpus_done(unsigned int max_cpus)
 682 {
 683         cpumask_var_t old_mask;
 684
 685         /* We want the setup_cpu() here to be called from CPU 0, but our
 686          * init thread may have been "borrowed" by another CPU in the meantime
 687          * se we pin us down to CPU 0 for a short while
 688          */
 689         alloc_cpumask_var(&old_mask, GFP_NOWAIT);
 690         cpumask_copy(old_mask, tsk_cpus_allowed(current));
 691         set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid));
 692
 693         if (smp_ops && smp_ops->setup_cpu)
 694                 smp_ops->setup_cpu(boot_cpuid);
 695
 696         set_cpus_allowed_ptr(current, old_mask);
 697
 698         free_cpumask_var(old_mask);
 699
 700         if (smp_ops && smp_ops->bringup_done)
 701                 smp_ops->bringup_done();
 702
 703         dump_numa_cpu_topology();
 704
 705 }
 706
 707 int arch_sd_sibling_asym_packing(void)
 708 {
 709         if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
 710                 printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
 711                 return SD_ASYM_PACKING;
 712         }
 713         return 0;
 714 }
 715
 716 #ifdef CONFIG_HOTPLUG_CPU
 717 int __cpu_disable(void)
 718 {
 719         struct device_node *l2_cache;
 720         int cpu = smp_processor_id();
 721         int base, i;
 722         int err;
 723
 724         if (!smp_ops->cpu_disable)
 725                 return -ENOSYS;
 726
 727         err = smp_ops->cpu_disable();
 728         if (err)
 729                 return err;
 730
 731         /* Update sibling maps */
 732         base = cpu_first_thread_sibling(cpu);
 733         for (i = 0; i < threads_per_core; i++) {
 734                 cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i));
 735                 cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu));
 736                 cpumask_clear_cpu(cpu, cpu_core_mask(base + i));
 737                 cpumask_clear_cpu(base + i, cpu_core_mask(cpu));
 738         }
 739
 740         l2_cache = cpu_to_l2cache(cpu);
 741         for_each_present_cpu(i) {
 742                 struct device_node *np = cpu_to_l2cache(i);
 743                 if (!np)
 744                         continue;
 745                 if (np == l2_cache) {
 746                         cpumask_clear_cpu(cpu, cpu_core_mask(i));
 747                         cpumask_clear_cpu(i, cpu_core_mask(cpu));
 748                 }
 749                 of_node_put(np);
 750         }
 751         of_node_put(l2_cache);
 752
 753
 754         return 0;
 755 }
 756
 757 void __cpu_die(unsigned int cpu)
 758 {
 759         if (smp_ops->cpu_die)
 760                 smp_ops->cpu_die(cpu);
 761 }
 762
 763 static DEFINE_MUTEX(powerpc_cpu_hotplug_driver_mutex);
 764
 765 void cpu_hotplug_driver_lock()
 766 {
 767         mutex_lock(&powerpc_cpu_hotplug_driver_mutex);
 768 }
 769
 770 void cpu_hotplug_driver_unlock()
 771 {
 772         mutex_unlock(&powerpc_cpu_hotplug_driver_mutex);
 773 }
 774
 775 void cpu_die(void)
 776 {
 777         if (ppc_md.cpu_die)
 778                 ppc_md.cpu_die();
 779
 780         /* If we return, we re-enter start_secondary */
 781         start_secondary_resume();
 782 }
 783
 784 #endif