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