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 struct thread_info *secondary_ti;
  61
  62 DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
  63 DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
  64
  65 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
  66 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
  67
  68 /* SMP operations for this machine */
  69 struct smp_ops_t *smp_ops;
  70
  71 /* Can't be static due to PowerMac hackery */
  72 volatile unsigned int cpu_callin_map[NR_CPUS];
  73
  74 int smt_enabled_at_boot = 1;
  75
  76 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
  77
  78 #ifdef CONFIG_PPC64
  79 void __devinit smp_generic_kick_cpu(int nr)
  80 {
  81         BUG_ON(nr < 0 || nr >= NR_CPUS);
  82
  83         /*
  84          * The processor is currently spinning, waiting for the
  85          * cpu_start field to become non-zero After we set cpu_start,
  86          * the processor will continue on to secondary_start
  87          */
  88         paca[nr].cpu_start = 1;
  89         smp_mb();
  90 }
  91 #endif
  92
  93 void smp_message_recv(int msg)
  94 {
  95         switch(msg) {
  96         case PPC_MSG_CALL_FUNCTION:
  97                 generic_smp_call_function_interrupt();
  98                 break;
  99         case PPC_MSG_RESCHEDULE:
 100                 /* we notice need_resched on exit */
 101                 break;
 102         case PPC_MSG_CALL_FUNC_SINGLE:
 103                 generic_smp_call_function_single_interrupt();
 104                 break;
 105         case PPC_MSG_DEBUGGER_BREAK:
 106                 if (crash_ipi_function_ptr) {
 107                         crash_ipi_function_ptr(get_irq_regs());
 108                         break;
 109                 }
 110 #ifdef CONFIG_DEBUGGER
 111                 debugger_ipi(get_irq_regs());
 112                 break;
 113 #endif /* CONFIG_DEBUGGER */
 114                 /* FALLTHROUGH */
 115         default:
 116                 printk("SMP %d: smp_message_recv(): unknown msg %d\n",
 117                        smp_processor_id(), msg);
 118                 break;
 119         }
 120 }
 121
 122 static irqreturn_t call_function_action(int irq, void *data)
 123 {
 124         generic_smp_call_function_interrupt();
 125         return IRQ_HANDLED;
 126 }
 127
 128 static irqreturn_t reschedule_action(int irq, void *data)
 129 {
 130         /* we just need the return path side effect of checking need_resched */
 131         return IRQ_HANDLED;
 132 }
 133
 134 static irqreturn_t call_function_single_action(int irq, void *data)
 135 {
 136         generic_smp_call_function_single_interrupt();
 137         return IRQ_HANDLED;
 138 }
 139
 140 static irqreturn_t debug_ipi_action(int irq, void *data)
 141 {
 142         smp_message_recv(PPC_MSG_DEBUGGER_BREAK);
 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 void smp_send_reschedule(int cpu)
 182 {
 183         if (likely(smp_ops))
 184                 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
 185 }
 186
 187 void arch_send_call_function_single_ipi(int cpu)
 188 {
 189         smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
 190 }
 191
 192 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 193 {
 194         unsigned int cpu;
 195
 196         for_each_cpu(cpu, mask)
 197                 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);
 198 }
 199
 200 #ifdef CONFIG_DEBUGGER
 201 void smp_send_debugger_break(int cpu)
 202 {
 203         if (likely(smp_ops))
 204                 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 205 }
 206 #endif
 207
 208 #ifdef CONFIG_KEXEC
 209 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 210 {
 211         crash_ipi_function_ptr = crash_ipi_callback;
 212         if (crash_ipi_callback && smp_ops) {
 213                 mb();
 214                 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
 215         }
 216 }
 217 #endif
 218
 219 static void stop_this_cpu(void *dummy)
 220 {
 221         /* Remove this CPU */
 222         set_cpu_online(smp_processor_id(), false);
 223
 224         local_irq_disable();
 225         while (1)
 226                 ;
 227 }
 228
 229 void smp_send_stop(void)
 230 {
 231         smp_call_function(stop_this_cpu, NULL, 0);
 232 }
 233
 234 struct thread_info *current_set[NR_CPUS];
 235
 236 static void __devinit smp_store_cpu_info(int id)
 237 {
 238         per_cpu(cpu_pvr, id) = mfspr(SPRN_PVR);
 239 }
 240
 241 static void __init smp_create_idle(unsigned int cpu)
 242 {
 243         struct task_struct *p;
 244
 245         /* create a process for the processor */
 246         p = fork_idle(cpu);
 247         if (IS_ERR(p))
 248                 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
 249 #ifdef CONFIG_PPC64
 250         paca[cpu].__current = p;
 251         paca[cpu].kstack = (unsigned long) task_thread_info(p)
 252                 + THREAD_SIZE - STACK_FRAME_OVERHEAD;
 253 #endif
 254         current_set[cpu] = task_thread_info(p);
 255         task_thread_info(p)->cpu = cpu;
 256 }
 257
 258 void __init smp_prepare_cpus(unsigned int max_cpus)
 259 {
 260         unsigned int cpu;
 261
 262         DBG("smp_prepare_cpus\n");
 263
 264         /*
 265          * setup_cpu may need to be called on the boot cpu. We havent
 266          * spun any cpus up but lets be paranoid.
 267          */
 268         BUG_ON(boot_cpuid != smp_processor_id());
 269
 270         /* Fixup boot cpu */
 271         smp_store_cpu_info(boot_cpuid);
 272         cpu_callin_map[boot_cpuid] = 1;
 273
 274         for_each_possible_cpu(cpu) {
 275                 zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu),
 276                                         GFP_KERNEL, cpu_to_node(cpu));
 277                 zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
 278                                         GFP_KERNEL, cpu_to_node(cpu));
 279         }
 280
 281         cpumask_set_cpu(boot_cpuid, cpu_sibling_mask(boot_cpuid));
 282         cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
 283
 284         if (smp_ops)
 285                 if (smp_ops->probe)
 286                         max_cpus = smp_ops->probe();
 287                 else
 288                         max_cpus = NR_CPUS;
 289         else
 290                 max_cpus = 1;
 291
 292         for_each_possible_cpu(cpu)
 293                 if (cpu != boot_cpuid)
 294                         smp_create_idle(cpu);
 295 }
 296
 297 void __devinit smp_prepare_boot_cpu(void)
 298 {
 299         BUG_ON(smp_processor_id() != boot_cpuid);
 300 #ifdef CONFIG_PPC64
 301         paca[boot_cpuid].__current = current;
 302 #endif
 303         current_set[boot_cpuid] = task_thread_info(current);
 304 }
 305
 306 #ifdef CONFIG_HOTPLUG_CPU
 307 /* State of each CPU during hotplug phases */
 308 DEFINE_PER_CPU(int, cpu_state) = { 0 };
 309
 310 int generic_cpu_disable(void)
 311 {
 312         unsigned int cpu = smp_processor_id();
 313
 314         if (cpu == boot_cpuid)
 315                 return -EBUSY;
 316
 317         set_cpu_online(cpu, false);
 318 #ifdef CONFIG_PPC64
 319         vdso_data->processorCount--;
 320         fixup_irqs(cpu_online_mask);
 321 #endif
 322         return 0;
 323 }
 324
 325 int generic_cpu_enable(unsigned int cpu)
 326 {
 327         /* Do the normal bootup if we haven't
 328          * already bootstrapped. */
 329         if (system_state != SYSTEM_RUNNING)
 330                 return -ENOSYS;
 331
 332         /* get the target out of it's holding state */
 333         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 334         smp_wmb();
 335
 336         while (!cpu_online(cpu))
 337                 cpu_relax();
 338
 339 #ifdef CONFIG_PPC64
 340         fixup_irqs(cpu_online_mask);
 341         /* counter the irq disable in fixup_irqs */
 342         local_irq_enable();
 343 #endif
 344         return 0;
 345 }
 346
 347 void generic_cpu_die(unsigned int cpu)
 348 {
 349         int i;
 350
 351         for (i = 0; i < 100; i++) {
 352                 smp_rmb();
 353                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 354                         return;
 355                 msleep(100);
 356         }
 357         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 358 }
 359
 360 void generic_mach_cpu_die(void)
 361 {
 362         unsigned int cpu;
 363
 364         local_irq_disable();
 365         cpu = smp_processor_id();
 366         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 367         __get_cpu_var(cpu_state) = CPU_DEAD;
 368         smp_wmb();
 369         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 370                 cpu_relax();
 371         set_cpu_online(cpu, true);
 372         local_irq_enable();
 373 }
 374 #endif
 375
 376 static int __devinit cpu_enable(unsigned int cpu)
 377 {
 378         if (smp_ops && smp_ops->cpu_enable)
 379                 return smp_ops->cpu_enable(cpu);
 380
 381         return -ENOSYS;
 382 }
 383
 384 int __cpuinit __cpu_up(unsigned int cpu)
 385 {
 386         int c;
 387
 388         secondary_ti = current_set[cpu];
 389         if (!cpu_enable(cpu))
 390                 return 0;
 391
 392         if (smp_ops == NULL ||
 393             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 394                 return -EINVAL;
 395
 396         /* Make sure callin-map entry is 0 (can be leftover a CPU
 397          * hotplug
 398          */
 399         cpu_callin_map[cpu] = 0;
 400
 401         /* The information for processor bringup must
 402          * be written out to main store before we release
 403          * the processor.
 404          */
 405         smp_mb();
 406
 407         /* wake up cpus */
 408         DBG("smp: kicking cpu %d\n", cpu);
 409         smp_ops->kick_cpu(cpu);
 410
 411         /*
 412          * wait to see if the cpu made a callin (is actually up).
 413          * use this value that I found through experimentation.
 414          * -- Cort
 415          */
 416         if (system_state < SYSTEM_RUNNING)
 417                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
 418                         udelay(100);
 419 #ifdef CONFIG_HOTPLUG_CPU
 420         else
 421                 /*
 422                  * CPUs can take much longer to come up in the
 423                  * hotplug case.  Wait five seconds.
 424                  */
 425                 for (c = 5000; c && !cpu_callin_map[cpu]; c--)
 426                         msleep(1);
 427 #endif
 428
 429         if (!cpu_callin_map[cpu]) {
 430                 printk(KERN_ERR "Processor %u is stuck.\n", cpu);
 431                 return -ENOENT;
 432         }
 433
 434         DBG("Processor %u found.\n", cpu);
 435
 436         if (smp_ops->give_timebase)
 437                 smp_ops->give_timebase();
 438
 439         /* Wait until cpu puts itself in the online map */
 440         while (!cpu_online(cpu))
 441                 cpu_relax();
 442
 443         return 0;
 444 }
 445
 446 /* Return the value of the reg property corresponding to the given
 447  * logical cpu.
 448  */
 449 int cpu_to_core_id(int cpu)
 450 {
 451         struct device_node *np;
 452         const int *reg;
 453         int id = -1;
 454
 455         np = of_get_cpu_node(cpu, NULL);
 456         if (!np)
 457                 goto out;
 458
 459         reg = of_get_property(np, "reg", NULL);
 460         if (!reg)
 461                 goto out;
 462
 463         id = *reg;
 464 out:
 465         of_node_put(np);
 466         return id;
 467 }
 468
 469 /* Helper routines for cpu to core mapping */
 470 int cpu_core_index_of_thread(int cpu)
 471 {
 472         return cpu >> threads_shift;
 473 }
 474 EXPORT_SYMBOL_GPL(cpu_core_index_of_thread);
 475
 476 int cpu_first_thread_of_core(int core)
 477 {
 478         return core << threads_shift;
 479 }
 480 EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);
 481
 482 /* Must be called when no change can occur to cpu_present_map,
 483  * i.e. during cpu online or offline.
 484  */
 485 static struct device_node *cpu_to_l2cache(int cpu)
 486 {
 487         struct device_node *np;
 488         struct device_node *cache;
 489
 490         if (!cpu_present(cpu))
 491                 return NULL;
 492
 493         np = of_get_cpu_node(cpu, NULL);
 494         if (np == NULL)
 495                 return NULL;
 496
 497         cache = of_find_next_cache_node(np);
 498
 499         of_node_put(np);
 500
 501         return cache;
 502 }
 503
 504 /* Activate a secondary processor. */
 505 int __devinit start_secondary(void *unused)
 506 {
 507         unsigned int cpu = smp_processor_id();
 508         struct device_node *l2_cache;
 509         int i, base;
 510
 511         atomic_inc(&init_mm.mm_count);
 512         current->active_mm = &init_mm;
 513
 514         smp_store_cpu_info(cpu);
 515         set_dec(tb_ticks_per_jiffy);
 516         preempt_disable();
 517         cpu_callin_map[cpu] = 1;
 518
 519         if (smp_ops->setup_cpu)
 520                 smp_ops->setup_cpu(cpu);
 521         if (smp_ops->take_timebase)
 522                 smp_ops->take_timebase();
 523
 524         secondary_cpu_time_init();
 525
 526         ipi_call_lock();
 527         notify_cpu_starting(cpu);
 528         set_cpu_online(cpu, true);
 529         /* Update sibling maps */
 530         base = cpu_first_thread_sibling(cpu);
 531         for (i = 0; i < threads_per_core; i++) {
 532                 if (cpu_is_offline(base + i))
 533                         continue;
 534                 cpumask_set_cpu(cpu, cpu_sibling_mask(base + i));
 535                 cpumask_set_cpu(base + i, cpu_sibling_mask(cpu));
 536
 537                 /* cpu_core_map should be a superset of
 538                  * cpu_sibling_map even if we don't have cache
 539                  * information, so update the former here, too.
 540                  */
 541                 cpumask_set_cpu(cpu, cpu_core_mask(base + i));
 542                 cpumask_set_cpu(base + i, cpu_core_mask(cpu));
 543         }
 544         l2_cache = cpu_to_l2cache(cpu);
 545         for_each_online_cpu(i) {
 546                 struct device_node *np = cpu_to_l2cache(i);
 547                 if (!np)
 548                         continue;
 549                 if (np == l2_cache) {
 550                         cpumask_set_cpu(cpu, cpu_core_mask(i));
 551                         cpumask_set_cpu(i, cpu_core_mask(cpu));
 552                 }
 553                 of_node_put(np);
 554         }
 555         of_node_put(l2_cache);
 556         ipi_call_unlock();
 557
 558         local_irq_enable();
 559
 560         cpu_idle();
 561         return 0;
 562 }
 563
 564 int setup_profiling_timer(unsigned int multiplier)
 565 {
 566         return 0;
 567 }
 568
 569 void __init smp_cpus_done(unsigned int max_cpus)
 570 {
 571         cpumask_var_t old_mask;
 572
 573         /* We want the setup_cpu() here to be called from CPU 0, but our
 574          * init thread may have been "borrowed" by another CPU in the meantime
 575          * se we pin us down to CPU 0 for a short while
 576          */
 577         alloc_cpumask_var(&old_mask, GFP_NOWAIT);
 578         cpumask_copy(old_mask, &current->cpus_allowed);
 579         set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid));
 580
 581         if (smp_ops && smp_ops->setup_cpu)
 582                 smp_ops->setup_cpu(boot_cpuid);
 583
 584         set_cpus_allowed_ptr(current, old_mask);
 585
 586         free_cpumask_var(old_mask);
 587
 588         dump_numa_cpu_topology();
 589 }
 590
 591 int arch_sd_sibling_asym_packing(void)
 592 {
 593         if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
 594                 printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
 595                 return SD_ASYM_PACKING;
 596         }
 597         return 0;
 598 }
 599
 600 #ifdef CONFIG_HOTPLUG_CPU
 601 int __cpu_disable(void)
 602 {
 603         struct device_node *l2_cache;
 604         int cpu = smp_processor_id();
 605         int base, i;
 606         int err;
 607
 608         if (!smp_ops->cpu_disable)
 609                 return -ENOSYS;
 610
 611         err = smp_ops->cpu_disable();
 612         if (err)
 613                 return err;
 614
 615         /* Update sibling maps */
 616         base = cpu_first_thread_sibling(cpu);
 617         for (i = 0; i < threads_per_core; i++) {
 618                 cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i));
 619                 cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu));
 620                 cpumask_clear_cpu(cpu, cpu_core_mask(base + i));
 621                 cpumask_clear_cpu(base + i, cpu_core_mask(cpu));
 622         }
 623
 624         l2_cache = cpu_to_l2cache(cpu);
 625         for_each_present_cpu(i) {
 626                 struct device_node *np = cpu_to_l2cache(i);
 627                 if (!np)
 628                         continue;
 629                 if (np == l2_cache) {
 630                         cpumask_clear_cpu(cpu, cpu_core_mask(i));
 631                         cpumask_clear_cpu(i, cpu_core_mask(cpu));
 632                 }
 633                 of_node_put(np);
 634         }
 635         of_node_put(l2_cache);
 636
 637
 638         return 0;
 639 }
 640
 641 void __cpu_die(unsigned int cpu)
 642 {
 643         if (smp_ops->cpu_die)
 644                 smp_ops->cpu_die(cpu);
 645 }
 646
 647 static DEFINE_MUTEX(powerpc_cpu_hotplug_driver_mutex);
 648
 649 void cpu_hotplug_driver_lock()
 650 {
 651         mutex_lock(&powerpc_cpu_hotplug_driver_mutex);
 652 }
 653
 654 void cpu_hotplug_driver_unlock()
 655 {
 656         mutex_unlock(&powerpc_cpu_hotplug_driver_mutex);
 657 }
 658
 659 void cpu_die(void)
 660 {
 661         if (ppc_md.cpu_die)
 662                 ppc_md.cpu_die();
 663 }
 664 #endif