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/device.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],
 191                           IRQF_PERCPU | IRQF_NO_THREAD,
 192                           smp_ipi_name[msg], 0);
 193         WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n",
 194                 virq, smp_ipi_name[msg], err);
 195
 196         return err;
 197 }
 198
 199 #ifdef CONFIG_PPC_SMP_MUXED_IPI
 200 struct cpu_messages {
 201         int messages;                   /* current messages */
 202         unsigned long data;             /* data for cause ipi */
 203 };
 204 static DEFINE_PER_CPU_SHARED_ALIGNED(struct cpu_messages, ipi_message);
 205
 206 void smp_muxed_ipi_set_data(int cpu, unsigned long data)
 207 {
 208         struct cpu_messages *info = &per_cpu(ipi_message, cpu);
 209
 210         info->data = data;
 211 }
 212
 213 void smp_muxed_ipi_message_pass(int cpu, int msg)
 214 {
 215         struct cpu_messages *info = &per_cpu(ipi_message, cpu);
 216         char *message = (char *)&info->messages;
 217
 218         message[msg] = 1;
 219         mb();
 220         smp_ops->cause_ipi(cpu, info->data);
 221 }
 222
 223 irqreturn_t smp_ipi_demux(void)
 224 {
 225         struct cpu_messages *info = &__get_cpu_var(ipi_message);
 226         unsigned int all;
 227
 228         mb();   /* order any irq clear */
 229
 230         do {
 231                 all = xchg_local(&info->messages, 0);
 232
 233 #ifdef __BIG_ENDIAN
 234                 if (all & (1 << (24 - 8 * PPC_MSG_CALL_FUNCTION)))
 235                         generic_smp_call_function_interrupt();
 236                 if (all & (1 << (24 - 8 * PPC_MSG_RESCHEDULE)))
 237                         scheduler_ipi();
 238                 if (all & (1 << (24 - 8 * PPC_MSG_CALL_FUNC_SINGLE)))
 239                         generic_smp_call_function_single_interrupt();
 240                 if (all & (1 << (24 - 8 * PPC_MSG_DEBUGGER_BREAK)))
 241                         debug_ipi_action(0, NULL);
 242 #else
 243 #error Unsupported ENDIAN
 244 #endif
 245         } while (info->messages);
 246
 247         return IRQ_HANDLED;
 248 }
 249 #endif /* CONFIG_PPC_SMP_MUXED_IPI */
 250
 251 static inline void do_message_pass(int cpu, int msg)
 252 {
 253         if (smp_ops->message_pass)
 254                 smp_ops->message_pass(cpu, msg);
 255 #ifdef CONFIG_PPC_SMP_MUXED_IPI
 256         else
 257                 smp_muxed_ipi_message_pass(cpu, msg);
 258 #endif
 259 }
 260
 261 void smp_send_reschedule(int cpu)
 262 {
 263         if (likely(smp_ops))
 264                 do_message_pass(cpu, PPC_MSG_RESCHEDULE);
 265 }
 266 EXPORT_SYMBOL_GPL(smp_send_reschedule);
 267
 268 void arch_send_call_function_single_ipi(int cpu)
 269 {
 270         do_message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
 271 }
 272
 273 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 274 {
 275         unsigned int cpu;
 276
 277         for_each_cpu(cpu, mask)
 278                 do_message_pass(cpu, PPC_MSG_CALL_FUNCTION);
 279 }
 280
 281 #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
 282 void smp_send_debugger_break(void)
 283 {
 284         int cpu;
 285         int me = raw_smp_processor_id();
 286
 287         if (unlikely(!smp_ops))
 288                 return;
 289
 290         for_each_online_cpu(cpu)
 291                 if (cpu != me)
 292                         do_message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 293 }
 294 #endif
 295
 296 #ifdef CONFIG_KEXEC
 297 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 298 {
 299         crash_ipi_function_ptr = crash_ipi_callback;
 300         if (crash_ipi_callback) {
 301                 mb();
 302                 smp_send_debugger_break();
 303         }
 304 }
 305 #endif
 306
 307 static void stop_this_cpu(void *dummy)
 308 {
 309         /* Remove this CPU */
 310         set_cpu_online(smp_processor_id(), false);
 311
 312         local_irq_disable();
 313         while (1)
 314                 ;
 315 }
 316
 317 void smp_send_stop(void)
 318 {
 319         smp_call_function(stop_this_cpu, NULL, 0);
 320 }
 321
 322 struct thread_info *current_set[NR_CPUS];
 323
 324 static void __devinit smp_store_cpu_info(int id)
 325 {
 326         per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR);
 327 #ifdef CONFIG_PPC_FSL_BOOK3E
 328         per_cpu(next_tlbcam_idx, id)
 329                 = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) - 1;
 330 #endif
 331 }
 332
 333 void __init smp_prepare_cpus(unsigned int max_cpus)
 334 {
 335         unsigned int cpu;
 336
 337         DBG("smp_prepare_cpus\n");
 338
 339         /*
 340          * setup_cpu may need to be called on the boot cpu. We havent
 341          * spun any cpus up but lets be paranoid.
 342          */
 343         BUG_ON(boot_cpuid != smp_processor_id());
 344
 345         /* Fixup boot cpu */
 346         smp_store_cpu_info(boot_cpuid);
 347         cpu_callin_map[boot_cpuid] = 1;
 348
 349         for_each_possible_cpu(cpu) {
 350                 zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu),
 351                                         GFP_KERNEL, cpu_to_node(cpu));
 352                 zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
 353                                         GFP_KERNEL, cpu_to_node(cpu));
 354         }
 355
 356         cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid));
 357         cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
 358
 359         if (smp_ops)
 360                 if (smp_ops->probe)
 361                         max_cpus = smp_ops->probe();
 362                 else
 363                         max_cpus = NR_CPUS;
 364         else
 365                 max_cpus = 1;
 366 }
 367
 368 void __devinit smp_prepare_boot_cpu(void)
 369 {
 370         BUG_ON(smp_processor_id() != boot_cpuid);
 371 #ifdef CONFIG_PPC64
 372         paca[boot_cpuid].__current = current;
 373 #endif
 374         current_set[boot_cpuid] = task_thread_info(current);
 375 }
 376
 377 #ifdef CONFIG_HOTPLUG_CPU
 378
 379 int generic_cpu_disable(void)
 380 {
 381         unsigned int cpu = smp_processor_id();
 382
 383         if (cpu == boot_cpuid)
 384                 return -EBUSY;
 385
 386         set_cpu_online(cpu, false);
 387 #ifdef CONFIG_PPC64
 388         vdso_data->processorCount--;
 389 #endif
 390         migrate_irqs();
 391         return 0;
 392 }
 393
 394 void generic_cpu_die(unsigned int cpu)
 395 {
 396         int i;
 397
 398         for (i = 0; i < 100; i++) {
 399                 smp_rmb();
 400                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 401                         return;
 402                 msleep(100);
 403         }
 404         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 405 }
 406
 407 void generic_mach_cpu_die(void)
 408 {
 409         unsigned int cpu;
 410
 411         local_irq_disable();
 412         idle_task_exit();
 413         cpu = smp_processor_id();
 414         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 415         __get_cpu_var(cpu_state) = CPU_DEAD;
 416         smp_wmb();
 417         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 418                 cpu_relax();
 419 }
 420
 421 void generic_set_cpu_dead(unsigned int cpu)
 422 {
 423         per_cpu(cpu_state, cpu) = CPU_DEAD;
 424 }
 425
 426 int generic_check_cpu_restart(unsigned int cpu)
 427 {
 428         return per_cpu(cpu_state, cpu) == CPU_UP_PREPARE;
 429 }
 430 #endif
 431
 432 struct create_idle {
 433         struct work_struct work;
 434         struct task_struct *idle;
 435         struct completion done;
 436         int cpu;
 437 };
 438
 439 static void __cpuinit do_fork_idle(struct work_struct *work)
 440 {
 441         struct create_idle *c_idle =
 442                 container_of(work, struct create_idle, work);
 443
 444         c_idle->idle = fork_idle(c_idle->cpu);
 445         complete(&c_idle->done);
 446 }
 447
 448 static int __cpuinit create_idle(unsigned int cpu)
 449 {
 450         struct thread_info *ti;
 451         struct create_idle c_idle = {
 452                 .cpu    = cpu,
 453                 .done   = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
 454         };
 455         INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
 456
 457         c_idle.idle = get_idle_for_cpu(cpu);
 458
 459         /* We can't use kernel_thread since we must avoid to
 460          * reschedule the child. We use a workqueue because
 461          * we want to fork from a kernel thread, not whatever
 462          * userspace process happens to be trying to online us.
 463          */
 464         if (!c_idle.idle) {
 465                 schedule_work(&c_idle.work);
 466                 wait_for_completion(&c_idle.done);
 467         } else
 468                 init_idle(c_idle.idle, cpu);
 469         if (IS_ERR(c_idle.idle)) {
 470                 pr_err("Failed fork for CPU %u: %li", cpu, PTR_ERR(c_idle.idle));
 471                 return PTR_ERR(c_idle.idle);
 472         }
 473         ti = task_thread_info(c_idle.idle);
 474
 475 #ifdef CONFIG_PPC64
 476         paca[cpu].__current = c_idle.idle;
 477         paca[cpu].kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD;
 478 #endif
 479         ti->cpu = cpu;
 480         current_set[cpu] = ti;
 481
 482         return 0;
 483 }
 484
 485 int __cpuinit __cpu_up(unsigned int cpu)
 486 {
 487         int rc, c;
 488
 489         if (smp_ops == NULL ||
 490             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 491                 return -EINVAL;
 492
 493         /* Make sure we have an idle thread */
 494         rc = create_idle(cpu);
 495         if (rc)
 496                 return rc;
 497
 498         secondary_ti = current_set[cpu];
 499
 500         /* Make sure callin-map entry is 0 (can be leftover a CPU
 501          * hotplug
 502          */
 503         cpu_callin_map[cpu] = 0;
 504
 505         /* The information for processor bringup must
 506          * be written out to main store before we release
 507          * the processor.
 508          */
 509         smp_mb();
 510
 511         /* wake up cpus */
 512         DBG("smp: kicking cpu %d\n", cpu);
 513         rc = smp_ops->kick_cpu(cpu);
 514         if (rc) {
 515                 pr_err("smp: failed starting cpu %d (rc %d)\n", cpu, rc);
 516                 return rc;
 517         }
 518
 519         /*
 520          * wait to see if the cpu made a callin (is actually up).
 521          * use this value that I found through experimentation.
 522          * -- Cort
 523          */
 524         if (system_state < SYSTEM_RUNNING)
 525                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
 526                         udelay(100);
 527 #ifdef CONFIG_HOTPLUG_CPU
 528         else
 529                 /*
 530                  * CPUs can take much longer to come up in the
 531                  * hotplug case.  Wait five seconds.
 532                  */
 533                 for (c = 5000; c && !cpu_callin_map[cpu]; c--)
 534                         msleep(1);
 535 #endif
 536
 537         if (!cpu_callin_map[cpu]) {
 538                 printk(KERN_ERR "Processor %u is stuck.\n", cpu);
 539                 return -ENOENT;
 540         }
 541
 542         DBG("Processor %u found.\n", cpu);
 543
 544         if (smp_ops->give_timebase)
 545                 smp_ops->give_timebase();
 546
 547         /* Wait until cpu puts itself in the online map */
 548         while (!cpu_online(cpu))
 549                 cpu_relax();
 550
 551         return 0;
 552 }
 553
 554 /* Return the value of the reg property corresponding to the given
 555  * logical cpu.
 556  */
 557 int cpu_to_core_id(int cpu)
 558 {
 559         struct device_node *np;
 560         const int *reg;
 561         int id = -1;
 562
 563         np = of_get_cpu_node(cpu, NULL);
 564         if (!np)
 565                 goto out;
 566
 567         reg = of_get_property(np, "reg", NULL);
 568         if (!reg)
 569                 goto out;
 570
 571         id = *reg;
 572 out:
 573         of_node_put(np);
 574         return id;
 575 }
 576
 577 /* Helper routines for cpu to core mapping */
 578 int cpu_core_index_of_thread(int cpu)
 579 {
 580         return cpu >> threads_shift;
 581 }
 582 EXPORT_SYMBOL_GPL(cpu_core_index_of_thread);
 583
 584 int cpu_first_thread_of_core(int core)
 585 {
 586         return core << threads_shift;
 587 }
 588 EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);
 589
 590 /* Must be called when no change can occur to cpu_present_mask,
 591  * i.e. during cpu online or offline.
 592  */
 593 static struct device_node *cpu_to_l2cache(int cpu)
 594 {
 595         struct device_node *np;
 596         struct device_node *cache;
 597
 598         if (!cpu_present(cpu))
 599                 return NULL;
 600
 601         np = of_get_cpu_node(cpu, NULL);
 602         if (np == NULL)
 603                 return NULL;
 604
 605         cache = of_find_next_cache_node(np);
 606
 607         of_node_put(np);
 608
 609         return cache;
 610 }
 611
 612 /* Activate a secondary processor. */
 613 void __devinit start_secondary(void *unused)
 614 {
 615         unsigned int cpu = smp_processor_id();
 616         struct device_node *l2_cache;
 617         int i, base;
 618
 619         atomic_inc(&init_mm.mm_count);
 620         current->active_mm = &init_mm;
 621
 622         smp_store_cpu_info(cpu);
 623         set_dec(tb_ticks_per_jiffy);
 624         preempt_disable();
 625         cpu_callin_map[cpu] = 1;
 626
 627         if (smp_ops->setup_cpu)
 628                 smp_ops->setup_cpu(cpu);
 629         if (smp_ops->take_timebase)
 630                 smp_ops->take_timebase();
 631
 632         secondary_cpu_time_init();
 633
 634 #ifdef CONFIG_PPC64
 635         if (system_state == SYSTEM_RUNNING)
 636                 vdso_data->processorCount++;
 637 #endif
 638         ipi_call_lock();
 639         notify_cpu_starting(cpu);
 640         set_cpu_online(cpu, true);
 641         /* Update sibling maps */
 642         base = cpu_first_thread_sibling(cpu);
 643         for (i = 0; i < threads_per_core; i++) {
 644                 if (cpu_is_offline(base + i))
 645                         continue;
 646                 cpumask_set_cpu(cpu, cpu_sibling_mask(base + i));
 647                 cpumask_set_cpu(base + i, cpu_sibling_mask(cpu));
 648
 649                 /* cpu_core_map should be a superset of
 650                  * cpu_sibling_map even if we don't have cache
 651                  * information, so update the former here, too.
 652                  */
 653                 cpumask_set_cpu(cpu, cpu_core_mask(base + i));
 654                 cpumask_set_cpu(base + i, cpu_core_mask(cpu));
 655         }
 656         l2_cache = cpu_to_l2cache(cpu);
 657         for_each_online_cpu(i) {
 658                 struct device_node *np = cpu_to_l2cache(i);
 659                 if (!np)
 660                         continue;
 661                 if (np == l2_cache) {
 662                         cpumask_set_cpu(cpu, cpu_core_mask(i));
 663                         cpumask_set_cpu(i, cpu_core_mask(cpu));
 664                 }
 665                 of_node_put(np);
 666         }
 667         of_node_put(l2_cache);
 668         ipi_call_unlock();
 669
 670         local_irq_enable();
 671
 672         cpu_idle();
 673
 674         BUG();
 675 }
 676
 677 int setup_profiling_timer(unsigned int multiplier)
 678 {
 679         return 0;
 680 }
 681
 682 void __init smp_cpus_done(unsigned int max_cpus)
 683 {
 684         cpumask_var_t old_mask;
 685
 686         /* We want the setup_cpu() here to be called from CPU 0, but our
 687          * init thread may have been "borrowed" by another CPU in the meantime
 688          * se we pin us down to CPU 0 for a short while
 689          */
 690         alloc_cpumask_var(&old_mask, GFP_NOWAIT);
 691         cpumask_copy(old_mask, tsk_cpus_allowed(current));
 692         set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid));
 693
 694         if (smp_ops && smp_ops->setup_cpu)
 695                 smp_ops->setup_cpu(boot_cpuid);
 696
 697         set_cpus_allowed_ptr(current, old_mask);
 698
 699         free_cpumask_var(old_mask);
 700
 701         if (smp_ops && smp_ops->bringup_done)
 702                 smp_ops->bringup_done();
 703
 704         dump_numa_cpu_topology();
 705
 706 }
 707
 708 int arch_sd_sibling_asym_packing(void)
 709 {
 710         if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
 711                 printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
 712                 return SD_ASYM_PACKING;
 713         }
 714         return 0;
 715 }
 716
 717 #ifdef CONFIG_HOTPLUG_CPU
 718 int __cpu_disable(void)
 719 {
 720         struct device_node *l2_cache;
 721         int cpu = smp_processor_id();
 722         int base, i;
 723         int err;
 724
 725         if (!smp_ops->cpu_disable)
 726                 return -ENOSYS;
 727
 728         err = smp_ops->cpu_disable();
 729         if (err)
 730                 return err;
 731
 732         /* Update sibling maps */
 733         base = cpu_first_thread_sibling(cpu);
 734         for (i = 0; i < threads_per_core; i++) {
 735                 cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i));
 736                 cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu));
 737                 cpumask_clear_cpu(cpu, cpu_core_mask(base + i));
 738                 cpumask_clear_cpu(base + i, cpu_core_mask(cpu));
 739         }
 740
 741         l2_cache = cpu_to_l2cache(cpu);
 742         for_each_present_cpu(i) {
 743                 struct device_node *np = cpu_to_l2cache(i);
 744                 if (!np)
 745                         continue;
 746                 if (np == l2_cache) {
 747                         cpumask_clear_cpu(cpu, cpu_core_mask(i));
 748                         cpumask_clear_cpu(i, cpu_core_mask(cpu));
 749                 }
 750                 of_node_put(np);
 751         }
 752         of_node_put(l2_cache);
 753
 754
 755         return 0;
 756 }
 757
 758 void __cpu_die(unsigned int cpu)
 759 {
 760         if (smp_ops->cpu_die)
 761                 smp_ops->cpu_die(cpu);
 762 }
 763
 764 static DEFINE_MUTEX(powerpc_cpu_hotplug_driver_mutex);
 765
 766 void cpu_hotplug_driver_lock()
 767 {
 768         mutex_lock(&powerpc_cpu_hotplug_driver_mutex);
 769 }
 770
 771 void cpu_hotplug_driver_unlock()
 772 {
 773         mutex_unlock(&powerpc_cpu_hotplug_driver_mutex);
 774 }
 775
 776 void cpu_die(void)
 777 {
 778         if (ppc_md.cpu_die)
 779                 ppc_md.cpu_die();
 780
 781         /* If we return, we re-enter start_secondary */
 782         start_secondary_resume();
 783 }
 784
 785 #endif