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