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/mm.h>
  23 #include <linux/sched/topology.h>
  24 #include <linux/smp.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/delay.h>
  27 #include <linux/init.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/cache.h>
  30 #include <linux/err.h>
  31 #include <linux/device.h>
  32 #include <linux/cpu.h>
  33 #include <linux/notifier.h>
  34 #include <linux/topology.h>
  35 #include <linux/profile.h>
  36
  37 #include <asm/ptrace.h>
  38 #include <linux/atomic.h>
  39 #include <asm/irq.h>
  40 #include <asm/hw_irq.h>
  41 #include <asm/kvm_ppc.h>
  42 #include <asm/page.h>
  43 #include <asm/pgtable.h>
  44 #include <asm/prom.h>
  45 #include <asm/smp.h>
  46 #include <asm/time.h>
  47 #include <asm/machdep.h>
  48 #include <asm/cputhreads.h>
  49 #include <asm/cputable.h>
  50 #include <asm/mpic.h>
  51 #include <asm/vdso_datapage.h>
  52 #ifdef CONFIG_PPC64
  53 #include <asm/paca.h>
  54 #endif
  55 #include <asm/vdso.h>
  56 #include <asm/debug.h>
  57 #include <asm/kexec.h>
  58 #include <asm/asm-prototypes.h>
  59 #include <asm/cpu_has_feature.h>
  60
  61 #ifdef DEBUG
  62 #include <asm/udbg.h>
  63 #define DBG(fmt...) udbg_printf(fmt)
  64 #else
  65 #define DBG(fmt...)
  66 #endif
  67
  68 #ifdef CONFIG_HOTPLUG_CPU
  69 /* State of each CPU during hotplug phases */
  70 static DEFINE_PER_CPU(int, cpu_state) = { 0 };
  71 #endif
  72
  73 struct thread_info *secondary_ti;
  74
  75 DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
  76 DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
  77
  78 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
  79 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
  80
  81 /* SMP operations for this machine */
  82 struct smp_ops_t *smp_ops;
  83
  84 /* Can't be static due to PowerMac hackery */
  85 volatile unsigned int cpu_callin_map[NR_CPUS];
  86
  87 int smt_enabled_at_boot = 1;
  88
  89 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
  90
  91 /*
  92  * Returns 1 if the specified cpu should be brought up during boot.
  93  * Used to inhibit booting threads if they've been disabled or
  94  * limited on the command line
  95  */
  96 int smp_generic_cpu_bootable(unsigned int nr)
  97 {
  98         /* Special case - we inhibit secondary thread startup
  99          * during boot if the user requests it.
 100          */
 101         if (system_state == SYSTEM_BOOTING && cpu_has_feature(CPU_FTR_SMT)) {
 102                 if (!smt_enabled_at_boot && cpu_thread_in_core(nr) != 0)
 103                         return 0;
 104                 if (smt_enabled_at_boot
 105                     && cpu_thread_in_core(nr) >= smt_enabled_at_boot)
 106                         return 0;
 107         }
 108
 109         return 1;
 110 }
 111
 112
 113 #ifdef CONFIG_PPC64
 114 int smp_generic_kick_cpu(int nr)
 115 {
 116         BUG_ON(nr < 0 || nr >= NR_CPUS);
 117
 118         /*
 119          * The processor is currently spinning, waiting for the
 120          * cpu_start field to become non-zero After we set cpu_start,
 121          * the processor will continue on to secondary_start
 122          */
 123         if (!paca[nr].cpu_start) {
 124                 paca[nr].cpu_start = 1;
 125                 smp_mb();
 126                 return 0;
 127         }
 128
 129 #ifdef CONFIG_HOTPLUG_CPU
 130         /*
 131          * Ok it's not there, so it might be soft-unplugged, let's
 132          * try to bring it back
 133          */
 134         generic_set_cpu_up(nr);
 135         smp_wmb();
 136         smp_send_reschedule(nr);
 137 #endif /* CONFIG_HOTPLUG_CPU */
 138
 139         return 0;
 140 }
 141 #endif /* CONFIG_PPC64 */
 142
 143 static irqreturn_t call_function_action(int irq, void *data)
 144 {
 145         generic_smp_call_function_interrupt();
 146         return IRQ_HANDLED;
 147 }
 148
 149 static irqreturn_t reschedule_action(int irq, void *data)
 150 {
 151         scheduler_ipi();
 152         return IRQ_HANDLED;
 153 }
 154
 155 static irqreturn_t tick_broadcast_ipi_action(int irq, void *data)
 156 {
 157         tick_broadcast_ipi_handler();
 158         return IRQ_HANDLED;
 159 }
 160
 161 static irqreturn_t debug_ipi_action(int irq, void *data)
 162 {
 163         if (crash_ipi_function_ptr) {
 164                 crash_ipi_function_ptr(get_irq_regs());
 165                 return IRQ_HANDLED;
 166         }
 167
 168 #ifdef CONFIG_DEBUGGER
 169         debugger_ipi(get_irq_regs());
 170 #endif /* CONFIG_DEBUGGER */
 171
 172         return IRQ_HANDLED;
 173 }
 174
 175 static irq_handler_t smp_ipi_action[] = {
 176         [PPC_MSG_CALL_FUNCTION] =  call_function_action,
 177         [PPC_MSG_RESCHEDULE] = reschedule_action,
 178         [PPC_MSG_TICK_BROADCAST] = tick_broadcast_ipi_action,
 179         [PPC_MSG_DEBUGGER_BREAK] = debug_ipi_action,
 180 };
 181
 182 const char *smp_ipi_name[] = {
 183         [PPC_MSG_CALL_FUNCTION] =  "ipi call function",
 184         [PPC_MSG_RESCHEDULE] = "ipi reschedule",
 185         [PPC_MSG_TICK_BROADCAST] = "ipi tick-broadcast",
 186         [PPC_MSG_DEBUGGER_BREAK] = "ipi debugger",
 187 };
 188
 189 /* optional function to request ipi, for controllers with >= 4 ipis */
 190 int smp_request_message_ipi(int virq, int msg)
 191 {
 192         int err;
 193
 194         if (msg < 0 || msg > PPC_MSG_DEBUGGER_BREAK) {
 195                 return -EINVAL;
 196         }
 197 #if !defined(CONFIG_DEBUGGER) && !defined(CONFIG_KEXEC_CORE)
 198         if (msg == PPC_MSG_DEBUGGER_BREAK) {
 199                 return 1;
 200         }
 201 #endif
 202         err = request_irq(virq, smp_ipi_action[msg],
 203                           IRQF_PERCPU | IRQF_NO_THREAD | IRQF_NO_SUSPEND,
 204                           smp_ipi_name[msg], NULL);
 205         WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n",
 206                 virq, smp_ipi_name[msg], err);
 207
 208         return err;
 209 }
 210
 211 #ifdef CONFIG_PPC_SMP_MUXED_IPI
 212 struct cpu_messages {
 213         long messages;                  /* current messages */
 214         unsigned long data;             /* data for cause ipi */
 215 };
 216 static DEFINE_PER_CPU_SHARED_ALIGNED(struct cpu_messages, ipi_message);
 217
 218 void smp_muxed_ipi_set_data(int cpu, unsigned long data)
 219 {
 220         struct cpu_messages *info = &per_cpu(ipi_message, cpu);
 221
 222         info->data = data;
 223 }
 224
 225 void smp_muxed_ipi_set_message(int cpu, int msg)
 226 {
 227         struct cpu_messages *info = &per_cpu(ipi_message, cpu);
 228         char *message = (char *)&info->messages;
 229
 230         /*
 231          * Order previous accesses before accesses in the IPI handler.
 232          */
 233         smp_mb();
 234         message[msg] = 1;
 235 }
 236
 237 void smp_muxed_ipi_message_pass(int cpu, int msg)
 238 {
 239         struct cpu_messages *info = &per_cpu(ipi_message, cpu);
 240
 241         smp_muxed_ipi_set_message(cpu, msg);
 242         /*
 243          * cause_ipi functions are required to include a full barrier
 244          * before doing whatever causes the IPI.
 245          */
 246         smp_ops->cause_ipi(cpu, info->data);
 247 }
 248
 249 #ifdef __BIG_ENDIAN__
 250 #define IPI_MESSAGE(A) (1uL << ((BITS_PER_LONG - 8) - 8 * (A)))
 251 #else
 252 #define IPI_MESSAGE(A) (1uL << (8 * (A)))
 253 #endif
 254
 255 irqreturn_t smp_ipi_demux(void)
 256 {
 257         struct cpu_messages *info = this_cpu_ptr(&ipi_message);
 258         unsigned long all;
 259
 260         mb();   /* order any irq clear */
 261
 262         do {
 263                 all = xchg(&info->messages, 0);
 264 #if defined(CONFIG_KVM_XICS) && defined(CONFIG_KVM_BOOK3S_HV_POSSIBLE)
 265                 /*
 266                  * Must check for PPC_MSG_RM_HOST_ACTION messages
 267                  * before PPC_MSG_CALL_FUNCTION messages because when
 268                  * a VM is destroyed, we call kick_all_cpus_sync()
 269                  * to ensure that any pending PPC_MSG_RM_HOST_ACTION
 270                  * messages have completed before we free any VCPUs.
 271                  */
 272                 if (all & IPI_MESSAGE(PPC_MSG_RM_HOST_ACTION))
 273                         kvmppc_xics_ipi_action();
 274 #endif
 275                 if (all & IPI_MESSAGE(PPC_MSG_CALL_FUNCTION))
 276                         generic_smp_call_function_interrupt();
 277                 if (all & IPI_MESSAGE(PPC_MSG_RESCHEDULE))
 278                         scheduler_ipi();
 279                 if (all & IPI_MESSAGE(PPC_MSG_TICK_BROADCAST))
 280                         tick_broadcast_ipi_handler();
 281                 if (all & IPI_MESSAGE(PPC_MSG_DEBUGGER_BREAK))
 282                         debug_ipi_action(0, NULL);
 283         } while (info->messages);
 284
 285         return IRQ_HANDLED;
 286 }
 287 #endif /* CONFIG_PPC_SMP_MUXED_IPI */
 288
 289 static inline void do_message_pass(int cpu, int msg)
 290 {
 291         if (smp_ops->message_pass)
 292                 smp_ops->message_pass(cpu, msg);
 293 #ifdef CONFIG_PPC_SMP_MUXED_IPI
 294         else
 295                 smp_muxed_ipi_message_pass(cpu, msg);
 296 #endif
 297 }
 298
 299 void smp_send_reschedule(int cpu)
 300 {
 301         if (likely(smp_ops))
 302                 do_message_pass(cpu, PPC_MSG_RESCHEDULE);
 303 }
 304 EXPORT_SYMBOL_GPL(smp_send_reschedule);
 305
 306 void arch_send_call_function_single_ipi(int cpu)
 307 {
 308         do_message_pass(cpu, PPC_MSG_CALL_FUNCTION);
 309 }
 310
 311 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 312 {
 313         unsigned int cpu;
 314
 315         for_each_cpu(cpu, mask)
 316                 do_message_pass(cpu, PPC_MSG_CALL_FUNCTION);
 317 }
 318
 319 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 320 void tick_broadcast(const struct cpumask *mask)
 321 {
 322         unsigned int cpu;
 323
 324         for_each_cpu(cpu, mask)
 325                 do_message_pass(cpu, PPC_MSG_TICK_BROADCAST);
 326 }
 327 #endif
 328
 329 #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC_CORE)
 330 void smp_send_debugger_break(void)
 331 {
 332         int cpu;
 333         int me = raw_smp_processor_id();
 334
 335         if (unlikely(!smp_ops))
 336                 return;
 337
 338         for_each_online_cpu(cpu)
 339                 if (cpu != me)
 340                         do_message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 341 }
 342 #endif
 343
 344 #ifdef CONFIG_KEXEC_CORE
 345 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 346 {
 347         crash_ipi_function_ptr = crash_ipi_callback;
 348         if (crash_ipi_callback) {
 349                 mb();
 350                 smp_send_debugger_break();
 351         }
 352 }
 353 #endif
 354
 355 static void stop_this_cpu(void *dummy)
 356 {
 357         /* Remove this CPU */
 358         set_cpu_online(smp_processor_id(), false);
 359
 360         local_irq_disable();
 361         while (1)
 362                 ;
 363 }
 364
 365 void smp_send_stop(void)
 366 {
 367         smp_call_function(stop_this_cpu, NULL, 0);
 368 }
 369
 370 struct thread_info *current_set[NR_CPUS];
 371
 372 static void smp_store_cpu_info(int id)
 373 {
 374         per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR);
 375 #ifdef CONFIG_PPC_FSL_BOOK3E
 376         per_cpu(next_tlbcam_idx, id)
 377                 = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) - 1;
 378 #endif
 379 }
 380
 381 void __init smp_prepare_cpus(unsigned int max_cpus)
 382 {
 383         unsigned int cpu;
 384
 385         DBG("smp_prepare_cpus\n");
 386
 387         /*
 388          * setup_cpu may need to be called on the boot cpu. We havent
 389          * spun any cpus up but lets be paranoid.
 390          */
 391         BUG_ON(boot_cpuid != smp_processor_id());
 392
 393         /* Fixup boot cpu */
 394         smp_store_cpu_info(boot_cpuid);
 395         cpu_callin_map[boot_cpuid] = 1;
 396
 397         for_each_possible_cpu(cpu) {
 398                 zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu),
 399                                         GFP_KERNEL, cpu_to_node(cpu));
 400                 zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
 401                                         GFP_KERNEL, cpu_to_node(cpu));
 402                 /*
 403                  * numa_node_id() works after this.
 404                  */
 405                 if (cpu_present(cpu)) {
 406                         set_cpu_numa_node(cpu, numa_cpu_lookup_table[cpu]);
 407                         set_cpu_numa_mem(cpu,
 408                                 local_memory_node(numa_cpu_lookup_table[cpu]));
 409                 }
 410         }
 411
 412         cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid));
 413         cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
 414
 415         if (smp_ops && smp_ops->probe)
 416                 smp_ops->probe();
 417 }
 418
 419 void smp_prepare_boot_cpu(void)
 420 {
 421         BUG_ON(smp_processor_id() != boot_cpuid);
 422 #ifdef CONFIG_PPC64
 423         paca[boot_cpuid].__current = current;
 424 #endif
 425         set_numa_node(numa_cpu_lookup_table[boot_cpuid]);
 426         current_set[boot_cpuid] = task_thread_info(current);
 427 }
 428
 429 #ifdef CONFIG_HOTPLUG_CPU
 430
 431 int generic_cpu_disable(void)
 432 {
 433         unsigned int cpu = smp_processor_id();
 434
 435         if (cpu == boot_cpuid)
 436                 return -EBUSY;
 437
 438         set_cpu_online(cpu, false);
 439 #ifdef CONFIG_PPC64
 440         vdso_data->processorCount--;
 441 #endif
 442         /* Update affinity of all IRQs previously aimed at this CPU */
 443         irq_migrate_all_off_this_cpu();
 444
 445         /* Give the CPU time to drain in-flight ones */
 446         local_irq_enable();
 447         mdelay(1);
 448         local_irq_disable();
 449
 450         return 0;
 451 }
 452
 453 void generic_cpu_die(unsigned int cpu)
 454 {
 455         int i;
 456
 457         for (i = 0; i < 100; i++) {
 458                 smp_rmb();
 459                 if (is_cpu_dead(cpu))
 460                         return;
 461                 msleep(100);
 462         }
 463         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 464 }
 465
 466 void generic_set_cpu_dead(unsigned int cpu)
 467 {
 468         per_cpu(cpu_state, cpu) = CPU_DEAD;
 469 }
 470
 471 /*
 472  * The cpu_state should be set to CPU_UP_PREPARE in kick_cpu(), otherwise
 473  * the cpu_state is always CPU_DEAD after calling generic_set_cpu_dead(),
 474  * which makes the delay in generic_cpu_die() not happen.
 475  */
 476 void generic_set_cpu_up(unsigned int cpu)
 477 {
 478         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 479 }
 480
 481 int generic_check_cpu_restart(unsigned int cpu)
 482 {
 483         return per_cpu(cpu_state, cpu) == CPU_UP_PREPARE;
 484 }
 485
 486 int is_cpu_dead(unsigned int cpu)
 487 {
 488         return per_cpu(cpu_state, cpu) == CPU_DEAD;
 489 }
 490
 491 static bool secondaries_inhibited(void)
 492 {
 493         return kvm_hv_mode_active();
 494 }
 495
 496 #else /* HOTPLUG_CPU */
 497
 498 #define secondaries_inhibited()         0
 499
 500 #endif
 501
 502 static void cpu_idle_thread_init(unsigned int cpu, struct task_struct *idle)
 503 {
 504         struct thread_info *ti = task_thread_info(idle);
 505
 506 #ifdef CONFIG_PPC64
 507         paca[cpu].__current = idle;
 508         paca[cpu].kstack = (unsigned long)ti + THREAD_SIZE - STACK_FRAME_OVERHEAD;
 509 #endif
 510         ti->cpu = cpu;
 511         secondary_ti = current_set[cpu] = ti;
 512 }
 513
 514 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 515 {
 516         int rc, c;
 517
 518         /*
 519          * Don't allow secondary threads to come online if inhibited
 520          */
 521         if (threads_per_core > 1 && secondaries_inhibited() &&
 522             cpu_thread_in_subcore(cpu))
 523                 return -EBUSY;
 524
 525         if (smp_ops == NULL ||
 526             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 527                 return -EINVAL;
 528
 529         cpu_idle_thread_init(cpu, tidle);
 530
 531         /*
 532          * The platform might need to allocate resources prior to bringing
 533          * up the CPU
 534          */
 535         if (smp_ops->prepare_cpu) {
 536                 rc = smp_ops->prepare_cpu(cpu);
 537                 if (rc)
 538                         return rc;
 539         }
 540
 541         /* Make sure callin-map entry is 0 (can be leftover a CPU
 542          * hotplug
 543          */
 544         cpu_callin_map[cpu] = 0;
 545
 546         /* The information for processor bringup must
 547          * be written out to main store before we release
 548          * the processor.
 549          */
 550         smp_mb();
 551
 552         /* wake up cpus */
 553         DBG("smp: kicking cpu %d\n", cpu);
 554         rc = smp_ops->kick_cpu(cpu);
 555         if (rc) {
 556                 pr_err("smp: failed starting cpu %d (rc %d)\n", cpu, rc);
 557                 return rc;
 558         }
 559
 560         /*
 561          * wait to see if the cpu made a callin (is actually up).
 562          * use this value that I found through experimentation.
 563          * -- Cort
 564          */
 565         if (system_state < SYSTEM_RUNNING)
 566                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
 567                         udelay(100);
 568 #ifdef CONFIG_HOTPLUG_CPU
 569         else
 570                 /*
 571                  * CPUs can take much longer to come up in the
 572                  * hotplug case.  Wait five seconds.
 573                  */
 574                 for (c = 5000; c && !cpu_callin_map[cpu]; c--)
 575                         msleep(1);
 576 #endif
 577
 578         if (!cpu_callin_map[cpu]) {
 579                 printk(KERN_ERR "Processor %u is stuck.\n", cpu);
 580                 return -ENOENT;
 581         }
 582
 583         DBG("Processor %u found.\n", cpu);
 584
 585         if (smp_ops->give_timebase)
 586                 smp_ops->give_timebase();
 587
 588         /* Wait until cpu puts itself in the online & active maps */
 589         while (!cpu_online(cpu))
 590                 cpu_relax();
 591
 592         return 0;
 593 }
 594
 595 /* Return the value of the reg property corresponding to the given
 596  * logical cpu.
 597  */
 598 int cpu_to_core_id(int cpu)
 599 {
 600         struct device_node *np;
 601         const __be32 *reg;
 602         int id = -1;
 603
 604         np = of_get_cpu_node(cpu, NULL);
 605         if (!np)
 606                 goto out;
 607
 608         reg = of_get_property(np, "reg", NULL);
 609         if (!reg)
 610                 goto out;
 611
 612         id = be32_to_cpup(reg);
 613 out:
 614         of_node_put(np);
 615         return id;
 616 }
 617 EXPORT_SYMBOL_GPL(cpu_to_core_id);
 618
 619 /* Helper routines for cpu to core mapping */
 620 int cpu_core_index_of_thread(int cpu)
 621 {
 622         return cpu >> threads_shift;
 623 }
 624 EXPORT_SYMBOL_GPL(cpu_core_index_of_thread);
 625
 626 int cpu_first_thread_of_core(int core)
 627 {
 628         return core << threads_shift;
 629 }
 630 EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);
 631
 632 static void traverse_siblings_chip_id(int cpu, bool add, int chipid)
 633 {
 634         const struct cpumask *mask;
 635         struct device_node *np;
 636         int i, plen;
 637         const __be32 *prop;
 638
 639         mask = add ? cpu_online_mask : cpu_present_mask;
 640         for_each_cpu(i, mask) {
 641                 np = of_get_cpu_node(i, NULL);
 642                 if (!np)
 643                         continue;
 644                 prop = of_get_property(np, "ibm,chip-id", &plen);
 645                 if (prop && plen == sizeof(int) &&
 646                     of_read_number(prop, 1) == chipid) {
 647                         if (add) {
 648                                 cpumask_set_cpu(cpu, cpu_core_mask(i));
 649                                 cpumask_set_cpu(i, cpu_core_mask(cpu));
 650                         } else {
 651                                 cpumask_clear_cpu(cpu, cpu_core_mask(i));
 652                                 cpumask_clear_cpu(i, cpu_core_mask(cpu));
 653                         }
 654                 }
 655                 of_node_put(np);
 656         }
 657 }
 658
 659 /* Must be called when no change can occur to cpu_present_mask,
 660  * i.e. during cpu online or offline.
 661  */
 662 static struct device_node *cpu_to_l2cache(int cpu)
 663 {
 664         struct device_node *np;
 665         struct device_node *cache;
 666
 667         if (!cpu_present(cpu))
 668                 return NULL;
 669
 670         np = of_get_cpu_node(cpu, NULL);
 671         if (np == NULL)
 672                 return NULL;
 673
 674         cache = of_find_next_cache_node(np);
 675
 676         of_node_put(np);
 677
 678         return cache;
 679 }
 680
 681 static void traverse_core_siblings(int cpu, bool add)
 682 {
 683         struct device_node *l2_cache, *np;
 684         const struct cpumask *mask;
 685         int i, chip, plen;
 686         const __be32 *prop;
 687
 688         /* First see if we have ibm,chip-id properties in cpu nodes */
 689         np = of_get_cpu_node(cpu, NULL);
 690         if (np) {
 691                 chip = -1;
 692                 prop = of_get_property(np, "ibm,chip-id", &plen);
 693                 if (prop && plen == sizeof(int))
 694                         chip = of_read_number(prop, 1);
 695                 of_node_put(np);
 696                 if (chip >= 0) {
 697                         traverse_siblings_chip_id(cpu, add, chip);
 698                         return;
 699                 }
 700         }
 701
 702         l2_cache = cpu_to_l2cache(cpu);
 703         mask = add ? cpu_online_mask : cpu_present_mask;
 704         for_each_cpu(i, mask) {
 705                 np = cpu_to_l2cache(i);
 706                 if (!np)
 707                         continue;
 708                 if (np == l2_cache) {
 709                         if (add) {
 710                                 cpumask_set_cpu(cpu, cpu_core_mask(i));
 711                                 cpumask_set_cpu(i, cpu_core_mask(cpu));
 712                         } else {
 713                                 cpumask_clear_cpu(cpu, cpu_core_mask(i));
 714                                 cpumask_clear_cpu(i, cpu_core_mask(cpu));
 715                         }
 716                 }
 717                 of_node_put(np);
 718         }
 719         of_node_put(l2_cache);
 720 }
 721
 722 /* Activate a secondary processor. */
 723 void start_secondary(void *unused)
 724 {
 725         unsigned int cpu = smp_processor_id();
 726         int i, base;
 727
 728         mmgrab(&init_mm);
 729         current->active_mm = &init_mm;
 730
 731         smp_store_cpu_info(cpu);
 732         set_dec(tb_ticks_per_jiffy);
 733         preempt_disable();
 734         cpu_callin_map[cpu] = 1;
 735
 736         if (smp_ops->setup_cpu)
 737                 smp_ops->setup_cpu(cpu);
 738         if (smp_ops->take_timebase)
 739                 smp_ops->take_timebase();
 740
 741         secondary_cpu_time_init();
 742
 743 #ifdef CONFIG_PPC64
 744         if (system_state == SYSTEM_RUNNING)
 745                 vdso_data->processorCount++;
 746
 747         vdso_getcpu_init();
 748 #endif
 749         /* Update sibling maps */
 750         base = cpu_first_thread_sibling(cpu);
 751         for (i = 0; i < threads_per_core; i++) {
 752                 if (cpu_is_offline(base + i) && (cpu != base + i))
 753                         continue;
 754                 cpumask_set_cpu(cpu, cpu_sibling_mask(base + i));
 755                 cpumask_set_cpu(base + i, cpu_sibling_mask(cpu));
 756
 757                 /* cpu_core_map should be a superset of
 758                  * cpu_sibling_map even if we don't have cache
 759                  * information, so update the former here, too.
 760                  */
 761                 cpumask_set_cpu(cpu, cpu_core_mask(base + i));
 762                 cpumask_set_cpu(base + i, cpu_core_mask(cpu));
 763         }
 764         traverse_core_siblings(cpu, true);
 765
 766         set_numa_node(numa_cpu_lookup_table[cpu]);
 767         set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
 768
 769         smp_wmb();
 770         notify_cpu_starting(cpu);
 771         set_cpu_online(cpu, true);
 772
 773         local_irq_enable();
 774
 775         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 776
 777         BUG();
 778 }
 779
 780 int setup_profiling_timer(unsigned int multiplier)
 781 {
 782         return 0;
 783 }
 784
 785 #ifdef CONFIG_SCHED_SMT
 786 /* cpumask of CPUs with asymetric SMT dependancy */
 787 static int powerpc_smt_flags(void)
 788 {
 789         int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
 790
 791         if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
 792                 printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
 793                 flags |= SD_ASYM_PACKING;
 794         }
 795         return flags;
 796 }
 797 #endif
 798
 799 static struct sched_domain_topology_level powerpc_topology[] = {
 800 #ifdef CONFIG_SCHED_SMT
 801         { cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
 802 #endif
 803         { cpu_cpu_mask, SD_INIT_NAME(DIE) },
 804         { NULL, },
 805 };
 806
 807 void __init smp_cpus_done(unsigned int max_cpus)
 808 {
 809         cpumask_var_t old_mask;
 810
 811         /* We want the setup_cpu() here to be called from CPU 0, but our
 812          * init thread may have been "borrowed" by another CPU in the meantime
 813          * se we pin us down to CPU 0 for a short while
 814          */
 815         alloc_cpumask_var(&old_mask, GFP_NOWAIT);
 816         cpumask_copy(old_mask, &current->cpus_allowed);
 817         set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid));
 818
 819         if (smp_ops && smp_ops->setup_cpu)
 820                 smp_ops->setup_cpu(boot_cpuid);
 821
 822         set_cpus_allowed_ptr(current, old_mask);
 823
 824         free_cpumask_var(old_mask);
 825
 826         if (smp_ops && smp_ops->bringup_done)
 827                 smp_ops->bringup_done();
 828
 829         dump_numa_cpu_topology();
 830
 831         set_sched_topology(powerpc_topology);
 832
 833 }
 834
 835 #ifdef CONFIG_HOTPLUG_CPU
 836 int __cpu_disable(void)
 837 {
 838         int cpu = smp_processor_id();
 839         int base, i;
 840         int err;
 841
 842         if (!smp_ops->cpu_disable)
 843                 return -ENOSYS;
 844
 845         err = smp_ops->cpu_disable();
 846         if (err)
 847                 return err;
 848
 849         /* Update sibling maps */
 850         base = cpu_first_thread_sibling(cpu);
 851         for (i = 0; i < threads_per_core && base + i < nr_cpu_ids; i++) {
 852                 cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i));
 853                 cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu));
 854                 cpumask_clear_cpu(cpu, cpu_core_mask(base + i));
 855                 cpumask_clear_cpu(base + i, cpu_core_mask(cpu));
 856         }
 857         traverse_core_siblings(cpu, false);
 858
 859         return 0;
 860 }
 861
 862 void __cpu_die(unsigned int cpu)
 863 {
 864         if (smp_ops->cpu_die)
 865                 smp_ops->cpu_die(cpu);
 866 }
 867
 868 void cpu_die(void)
 869 {
 870         if (ppc_md.cpu_die)
 871                 ppc_md.cpu_die();
 872
 873         /* If we return, we re-enter start_secondary */
 874         start_secondary_resume();
 875 }
 876
 877 #endif