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