arch/powerpc/kernel/smp.c

   1 /*
   2  * SMP support for ppc.
   3  *
   4  * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great
   5  * deal of code from the sparc and intel versions.
   6  *
   7  * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
   8  *
   9  * PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and
  10  * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  */
  17
  18 #undef DEBUG
  19
  20 #include <linux/kernel.h>
  21 #include <linux/export.h>
  22 #include <linux/sched.h>
  23 #include <linux/smp.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/delay.h>
  26 #include <linux/init.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/cache.h>
  29 #include <linux/err.h>
  30 #include <linux/sysdev.h>
  31 #include <linux/cpu.h>
  32 #include <linux/notifier.h>
  33 #include <linux/topology.h>
  34
  35 #include <asm/ptrace.h>
  36 #include <linux/atomic.h>
  37 #include <asm/irq.h>
  38 #include <asm/page.h>
  39 #include <asm/pgtable.h>
  40 #include <asm/prom.h>
  41 #include <asm/smp.h>
  42 #include <asm/time.h>
  43 #include <asm/machdep.h>
  44 #include <asm/cputhreads.h>
  45 #include <asm/cputable.h>
  46 #include <asm/system.h>
  47 #include <asm/mpic.h>
  48 #include <asm/vdso_datapage.h>
  49 #ifdef CONFIG_PPC64
  50 #include <asm/paca.h>
  51 #endif
  52
  53 #ifdef DEBUG
  54 #include <asm/udbg.h>
  55 #define DBG(fmt...) udbg_printf(fmt)
  56 #else
  57 #define DBG(fmt...)
  58 #endif
  59
  60
  61 /* Store all idle threads, this can be reused instead of creating
  62 * a new thread. Also avoids complicated thread destroy functionality
  63 * for idle threads.
  64 */
  65 #ifdef CONFIG_HOTPLUG_CPU
  66 /*
  67  * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
  68  * removed after init for !CONFIG_HOTPLUG_CPU.
  69  */
  70 static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
  71 #define get_idle_for_cpu(x)      (per_cpu(idle_thread_array, x))
  72 #define set_idle_for_cpu(x, p)   (per_cpu(idle_thread_array, x) = (p))
  73 #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 EXPORT_SYMBOL_GPL(smp_send_reschedule);
 249
 250 void arch_send_call_function_single_ipi(int cpu)
 251 {
 252         do_message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
 253 }
 254
 255 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 256 {
 257         unsigned int cpu;
 258
 259         for_each_cpu(cpu, mask)
 260                 do_message_pass(cpu, PPC_MSG_CALL_FUNCTION);
 261 }
 262
 263 #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
 264 void smp_send_debugger_break(void)
 265 {
 266         int cpu;
 267         int me = raw_smp_processor_id();
 268
 269         if (unlikely(!smp_ops))
 270                 return;
 271
 272         for_each_online_cpu(cpu)
 273                 if (cpu != me)
 274                         do_message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 275 }
 276 #endif
 277
 278 #ifdef CONFIG_KEXEC
 279 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 280 {
 281         crash_ipi_function_ptr = crash_ipi_callback;
 282         if (crash_ipi_callback) {
 283                 mb();
 284                 smp_send_debugger_break();
 285         }
 286 }
 287 #endif
 288
 289 static void stop_this_cpu(void *dummy)
 290 {
 291         /* Remove this CPU */
 292         set_cpu_online(smp_processor_id(), false);
 293
 294         local_irq_disable();
 295         while (1)
 296                 ;
 297 }
 298
 299 void smp_send_stop(void)
 300 {
 301         smp_call_function(stop_this_cpu, NULL, 0);
 302 }
 303
 304 struct thread_info *current_set[NR_CPUS];
 305
 306 static void __devinit smp_store_cpu_info(int id)
 307 {
 308         per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR);
 309 #ifdef CONFIG_PPC_FSL_BOOK3E
 310         per_cpu(next_tlbcam_idx, id)
 311                 = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) - 1;
 312 #endif
 313 }
 314
 315 void __init smp_prepare_cpus(unsigned int max_cpus)
 316 {
 317         unsigned int cpu;
 318
 319         DBG("smp_prepare_cpus\n");
 320
 321         /*
 322          * setup_cpu may need to be called on the boot cpu. We havent
 323          * spun any cpus up but lets be paranoid.
 324          */
 325         BUG_ON(boot_cpuid != smp_processor_id());
 326
 327         /* Fixup boot cpu */
 328         smp_store_cpu_info(boot_cpuid);
 329         cpu_callin_map[boot_cpuid] = 1;
 330
 331         for_each_possible_cpu(cpu) {
 332                 zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu),
 333                                         GFP_KERNEL, cpu_to_node(cpu));
 334                 zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
 335                                         GFP_KERNEL, cpu_to_node(cpu));
 336         }
 337
 338         cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid));
 339         cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
 340
 341         if (smp_ops)
 342                 if (smp_ops->probe)
 343                         max_cpus = smp_ops->probe();
 344                 else
 345                         max_cpus = NR_CPUS;
 346         else
 347                 max_cpus = 1;
 348 }
 349
 350 void __devinit smp_prepare_boot_cpu(void)
 351 {
 352         BUG_ON(smp_processor_id() != boot_cpuid);
 353 #ifdef CONFIG_PPC64
 354         paca[boot_cpuid].__current = current;
 355 #endif
 356         current_set[boot_cpuid] = task_thread_info(current);
 357 }
 358
 359 #ifdef CONFIG_HOTPLUG_CPU
 360 /* State of each CPU during hotplug phases */
 361 static DEFINE_PER_CPU(int, cpu_state) = { 0 };
 362
 363 int generic_cpu_disable(void)
 364 {
 365         unsigned int cpu = smp_processor_id();
 366
 367         if (cpu == boot_cpuid)
 368                 return -EBUSY;
 369
 370         set_cpu_online(cpu, false);
 371 #ifdef CONFIG_PPC64
 372         vdso_data->processorCount--;
 373 #endif
 374         migrate_irqs();
 375         return 0;
 376 }
 377
 378 void generic_cpu_die(unsigned int cpu)
 379 {
 380         int i;
 381
 382         for (i = 0; i < 100; i++) {
 383                 smp_rmb();
 384                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 385                         return;
 386                 msleep(100);
 387         }
 388         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 389 }
 390
 391 void generic_mach_cpu_die(void)
 392 {
 393         unsigned int cpu;
 394
 395         local_irq_disable();
 396         idle_task_exit();
 397         cpu = smp_processor_id();
 398         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 399         __get_cpu_var(cpu_state) = CPU_DEAD;
 400         smp_wmb();
 401         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 402                 cpu_relax();
 403 }
 404
 405 void generic_set_cpu_dead(unsigned int cpu)
 406 {
 407         per_cpu(cpu_state, cpu) = CPU_DEAD;
 408 }
 409 #endif
 410
 411 struct create_idle {
 412         struct work_struct work;
 413         struct task_struct *idle;
 414         struct completion done;
 415         int cpu;
 416 };
 417
 418 static void __cpuinit do_fork_idle(struct work_struct *work)
 419 {
 420         struct create_idle *c_idle =
 421                 container_of(work, struct create_idle, work);
 422
 423         c_idle->idle = fork_idle(c_idle->cpu);
 424         complete(&c_idle->done);
 425 }
 426
 427 static int __cpuinit create_idle(unsigned int cpu)
 428 {
 429         struct thread_info *ti;
 430         struct create_idle c_idle = {
 431                 .cpu    = cpu,
 432                 .done   = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
 433         };
 434         INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
 435
 436         c_idle.idle = get_idle_for_cpu(cpu);
 437
 438         /* We can't use kernel_thread since we must avoid to
 439          * reschedule the child. We use a workqueue because
 440          * we want to fork from a kernel thread, not whatever
 441          * userspace process happens to be trying to online us.
 442          */
 443         if (!c_idle.idle) {
 444                 schedule_work(&c_idle.work);
 445                 wait_for_completion(&c_idle.done);
 446         } else
 447                 init_idle(c_idle.idle, cpu);
 448         if (IS_ERR(c_idle.idle)) {
 449                 pr_err("Failed fork for CPU %u: %li", cpu, PTR_ERR(c_idle.idle));
 450                 return PTR_ERR(c_idle.idle);
 451         }
 452         ti = task_thread_info(c_idle.idle);
 453
 454 #ifdef CONFIG_PPC64
 455         paca[cpu].__current = c_idle.idle;
 456         paca[cpu].kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD;
 457 #endif
 458         ti->cpu = cpu;
 459         current_set[cpu] = ti;
 460
 461         return 0;
 462 }
 463
 464 int __cpuinit __cpu_up(unsigned int cpu)
 465 {
 466         int rc, c;
 467
 468         if (smp_ops == NULL ||
 469             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 470                 return -EINVAL;
 471
 472         /* Make sure we have an idle thread */
 473         rc = create_idle(cpu);
 474         if (rc)
 475                 return rc;
 476
 477         secondary_ti = current_set[cpu];
 478
 479         /* Make sure callin-map entry is 0 (can be leftover a CPU
 480          * hotplug
 481          */
 482         cpu_callin_map[cpu] = 0;
 483
 484         /* The information for processor bringup must
 485          * be written out to main store before we release
 486          * the processor.
 487          */
 488         smp_mb();
 489
 490         /* wake up cpus */
 491         DBG("smp: kicking cpu %d\n", cpu);
 492         rc = smp_ops->kick_cpu(cpu);
 493         if (rc) {
 494                 pr_err("smp: failed starting cpu %d (rc %d)\n", cpu, rc);
 495                 return rc;
 496         }
 497
 498         /*
 499          * wait to see if the cpu made a callin (is actually up).
 500          * use this value that I found through experimentation.
 501          * -- Cort
 502          */
 503         if (system_state < SYSTEM_RUNNING)
 504                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
 505                         udelay(100);
 506 #ifdef CONFIG_HOTPLUG_CPU
 507         else
 508                 /*
 509                  * CPUs can take much longer to come up in the
 510                  * hotplug case.  Wait five seconds.
 511                  */
 512                 for (c = 5000; c && !cpu_callin_map[cpu]; c--)
 513                         msleep(1);
 514 #endif
 515
 516         if (!cpu_callin_map[cpu]) {
 517                 printk(KERN_ERR "Processor %u is stuck.\n", cpu);
 518                 return -ENOENT;
 519         }
 520
 521         DBG("Processor %u found.\n", cpu);
 522
 523         if (smp_ops->give_timebase)
 524                 smp_ops->give_timebase();
 525
 526         /* Wait until cpu puts itself in the online map */
 527         while (!cpu_online(cpu))
 528                 cpu_relax();
 529
 530         return 0;
 531 }
 532
 533 /* Return the value of the reg property corresponding to the given
 534  * logical cpu.
 535  */
 536 int cpu_to_core_id(int cpu)
 537 {
 538         struct device_node *np;
 539         const int *reg;
 540         int id = -1;
 541
 542         np = of_get_cpu_node(cpu, NULL);
 543         if (!np)
 544                 goto out;
 545
 546         reg = of_get_property(np, "reg", NULL);
 547         if (!reg)
 548                 goto out;
 549
 550         id = *reg;
 551 out:
 552         of_node_put(np);
 553         return id;
 554 }
 555
 556 /* Helper routines for cpu to core mapping */
 557 int cpu_core_index_of_thread(int cpu)
 558 {
 559         return cpu >> threads_shift;
 560 }
 561 EXPORT_SYMBOL_GPL(cpu_core_index_of_thread);
 562
 563 int cpu_first_thread_of_core(int core)
 564 {
 565         return core << threads_shift;
 566 }
 567 EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);
 568
 569 /* Must be called when no change can occur to cpu_present_mask,
 570  * i.e. during cpu online or offline.
 571  */
 572 static struct device_node *cpu_to_l2cache(int cpu)
 573 {
 574         struct device_node *np;
 575         struct device_node *cache;
 576
 577         if (!cpu_present(cpu))
 578                 return NULL;
 579
 580         np = of_get_cpu_node(cpu, NULL);
 581         if (np == NULL)
 582                 return NULL;
 583
 584         cache = of_find_next_cache_node(np);
 585
 586         of_node_put(np);
 587
 588         return cache;
 589 }
 590
 591 /* Activate a secondary processor. */
 592 void __devinit start_secondary(void *unused)
 593 {
 594         unsigned int cpu = smp_processor_id();
 595         struct device_node *l2_cache;
 596         int i, base;
 597
 598         atomic_inc(&init_mm.mm_count);
 599         current->active_mm = &init_mm;
 600
 601         smp_store_cpu_info(cpu);
 602         set_dec(tb_ticks_per_jiffy);
 603         preempt_disable();
 604         cpu_callin_map[cpu] = 1;
 605
 606         if (smp_ops->setup_cpu)
 607                 smp_ops->setup_cpu(cpu);
 608         if (smp_ops->take_timebase)
 609                 smp_ops->take_timebase();
 610
 611         secondary_cpu_time_init();
 612
 613 #ifdef CONFIG_PPC64
 614         if (system_state == SYSTEM_RUNNING)
 615                 vdso_data->processorCount++;
 616 #endif
 617         ipi_call_lock();
 618         notify_cpu_starting(cpu);
 619         set_cpu_online(cpu, true);
 620         /* Update sibling maps */
 621         base = cpu_first_thread_sibling(cpu);
 622         for (i = 0; i < threads_per_core; i++) {
 623                 if (cpu_is_offline(base + i))
 624                         continue;
 625                 cpumask_set_cpu(cpu, cpu_sibling_mask(base + i));
 626                 cpumask_set_cpu(base + i, cpu_sibling_mask(cpu));
 627
 628                 /* cpu_core_map should be a superset of
 629                  * cpu_sibling_map even if we don't have cache
 630                  * information, so update the former here, too.
 631                  */
 632                 cpumask_set_cpu(cpu, cpu_core_mask(base + i));
 633                 cpumask_set_cpu(base + i, cpu_core_mask(cpu));
 634         }
 635         l2_cache = cpu_to_l2cache(cpu);
 636         for_each_online_cpu(i) {
 637                 struct device_node *np = cpu_to_l2cache(i);
 638                 if (!np)
 639                         continue;
 640                 if (np == l2_cache) {
 641                         cpumask_set_cpu(cpu, cpu_core_mask(i));
 642                         cpumask_set_cpu(i, cpu_core_mask(cpu));
 643                 }
 644                 of_node_put(np);
 645         }
 646         of_node_put(l2_cache);
 647         ipi_call_unlock();
 648
 649         local_irq_enable();
 650
 651         cpu_idle();
 652
 653         BUG();
 654 }
 655
 656 int setup_profiling_timer(unsigned int multiplier)
 657 {
 658         return 0;
 659 }
 660
 661 void __init smp_cpus_done(unsigned int max_cpus)
 662 {
 663         cpumask_var_t old_mask;
 664
 665         /* We want the setup_cpu() here to be called from CPU 0, but our
 666          * init thread may have been "borrowed" by another CPU in the meantime
 667          * se we pin us down to CPU 0 for a short while
 668          */
 669         alloc_cpumask_var(&old_mask, GFP_NOWAIT);
 670         cpumask_copy(old_mask, tsk_cpus_allowed(current));
 671         set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid));
 672
 673         if (smp_ops && smp_ops->setup_cpu)
 674                 smp_ops->setup_cpu(boot_cpuid);
 675
 676         set_cpus_allowed_ptr(current, old_mask);
 677
 678         free_cpumask_var(old_mask);
 679
 680         if (smp_ops && smp_ops->bringup_done)
 681                 smp_ops->bringup_done();
 682
 683         dump_numa_cpu_topology();
 684
 685 }
 686
 687 int arch_sd_sibling_asym_packing(void)
 688 {
 689         if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
 690                 printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
 691                 return SD_ASYM_PACKING;
 692         }
 693         return 0;
 694 }
 695
 696 #ifdef CONFIG_HOTPLUG_CPU
 697 int __cpu_disable(void)
 698 {
 699         struct device_node *l2_cache;
 700         int cpu = smp_processor_id();
 701         int base, i;
 702         int err;
 703
 704         if (!smp_ops->cpu_disable)
 705                 return -ENOSYS;
 706
 707         err = smp_ops->cpu_disable();
 708         if (err)
 709                 return err;
 710
 711         /* Update sibling maps */
 712         base = cpu_first_thread_sibling(cpu);
 713         for (i = 0; i < threads_per_core; i++) {
 714                 cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i));
 715                 cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu));
 716                 cpumask_clear_cpu(cpu, cpu_core_mask(base + i));
 717                 cpumask_clear_cpu(base + i, cpu_core_mask(cpu));
 718         }
 719
 720         l2_cache = cpu_to_l2cache(cpu);
 721         for_each_present_cpu(i) {
 722                 struct device_node *np = cpu_to_l2cache(i);
 723                 if (!np)
 724                         continue;
 725                 if (np == l2_cache) {
 726                         cpumask_clear_cpu(cpu, cpu_core_mask(i));
 727                         cpumask_clear_cpu(i, cpu_core_mask(cpu));
 728                 }
 729                 of_node_put(np);
 730         }
 731         of_node_put(l2_cache);
 732
 733
 734         return 0;
 735 }
 736
 737 void __cpu_die(unsigned int cpu)
 738 {
 739         if (smp_ops->cpu_die)
 740                 smp_ops->cpu_die(cpu);
 741 }
 742
 743 static DEFINE_MUTEX(powerpc_cpu_hotplug_driver_mutex);
 744
 745 void cpu_hotplug_driver_lock()
 746 {
 747         mutex_lock(&powerpc_cpu_hotplug_driver_mutex);
 748 }
 749
 750 void cpu_hotplug_driver_unlock()
 751 {
 752         mutex_unlock(&powerpc_cpu_hotplug_driver_mutex);
 753 }
 754
 755 void cpu_die(void)
 756 {
 757         if (ppc_md.cpu_die)
 758                 ppc_md.cpu_die();
 759
 760         /* If we return, we re-enter start_secondary */
 761         start_secondary_resume();
 762 }
 763
 764 #endif