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_t, cpu_sibling_map) = CPU_MASK_NONE;
  63 DEFINE_PER_CPU(cpumask_t, cpu_core_map) = CPU_MASK_NONE;
  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         if (smp_ops)
 275                 if (smp_ops->probe)
 276                         max_cpus = smp_ops->probe();
 277                 else
 278                         max_cpus = NR_CPUS;
 279         else
 280                 max_cpus = 1;
 281
 282         smp_space_timers(max_cpus);
 283
 284         for_each_possible_cpu(cpu)
 285                 if (cpu != boot_cpuid)
 286                         smp_create_idle(cpu);
 287 }
 288
 289 void __devinit smp_prepare_boot_cpu(void)
 290 {
 291         BUG_ON(smp_processor_id() != boot_cpuid);
 292
 293         set_cpu_online(boot_cpuid, true);
 294         cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid));
 295         cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid));
 296 #ifdef CONFIG_PPC64
 297         paca[boot_cpuid].__current = current;
 298 #endif
 299         current_set[boot_cpuid] = task_thread_info(current);
 300 }
 301
 302 #ifdef CONFIG_HOTPLUG_CPU
 303 /* State of each CPU during hotplug phases */
 304 DEFINE_PER_CPU(int, cpu_state) = { 0 };
 305
 306 int generic_cpu_disable(void)
 307 {
 308         unsigned int cpu = smp_processor_id();
 309
 310         if (cpu == boot_cpuid)
 311                 return -EBUSY;
 312
 313         set_cpu_online(cpu, false);
 314 #ifdef CONFIG_PPC64
 315         vdso_data->processorCount--;
 316         fixup_irqs(cpu_online_map);
 317 #endif
 318         return 0;
 319 }
 320
 321 int generic_cpu_enable(unsigned int cpu)
 322 {
 323         /* Do the normal bootup if we haven't
 324          * already bootstrapped. */
 325         if (system_state != SYSTEM_RUNNING)
 326                 return -ENOSYS;
 327
 328         /* get the target out of it's holding state */
 329         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 330         smp_wmb();
 331
 332         while (!cpu_online(cpu))
 333                 cpu_relax();
 334
 335 #ifdef CONFIG_PPC64
 336         fixup_irqs(cpu_online_map);
 337         /* counter the irq disable in fixup_irqs */
 338         local_irq_enable();
 339 #endif
 340         return 0;
 341 }
 342
 343 void generic_cpu_die(unsigned int cpu)
 344 {
 345         int i;
 346
 347         for (i = 0; i < 100; i++) {
 348                 smp_rmb();
 349                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 350                         return;
 351                 msleep(100);
 352         }
 353         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 354 }
 355
 356 void generic_mach_cpu_die(void)
 357 {
 358         unsigned int cpu;
 359
 360         local_irq_disable();
 361         cpu = smp_processor_id();
 362         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 363         __get_cpu_var(cpu_state) = CPU_DEAD;
 364         smp_wmb();
 365         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 366                 cpu_relax();
 367         set_cpu_online(cpu, true);
 368         local_irq_enable();
 369 }
 370 #endif
 371
 372 static int __devinit cpu_enable(unsigned int cpu)
 373 {
 374         if (smp_ops && smp_ops->cpu_enable)
 375                 return smp_ops->cpu_enable(cpu);
 376
 377         return -ENOSYS;
 378 }
 379
 380 int __cpuinit __cpu_up(unsigned int cpu)
 381 {
 382         int c;
 383
 384         secondary_ti = current_set[cpu];
 385         if (!cpu_enable(cpu))
 386                 return 0;
 387
 388         if (smp_ops == NULL ||
 389             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 390                 return -EINVAL;
 391
 392         /* Make sure callin-map entry is 0 (can be leftover a CPU
 393          * hotplug
 394          */
 395         cpu_callin_map[cpu] = 0;
 396
 397         /* The information for processor bringup must
 398          * be written out to main store before we release
 399          * the processor.
 400          */
 401         smp_mb();
 402
 403         /* wake up cpus */
 404         DBG("smp: kicking cpu %d\n", cpu);
 405         smp_ops->kick_cpu(cpu);
 406
 407         /*
 408          * wait to see if the cpu made a callin (is actually up).
 409          * use this value that I found through experimentation.
 410          * -- Cort
 411          */
 412         if (system_state < SYSTEM_RUNNING)
 413                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
 414                         udelay(100);
 415 #ifdef CONFIG_HOTPLUG_CPU
 416         else
 417                 /*
 418                  * CPUs can take much longer to come up in the
 419                  * hotplug case.  Wait five seconds.
 420                  */
 421                 for (c = 5000; c && !cpu_callin_map[cpu]; c--)
 422                         msleep(1);
 423 #endif
 424
 425         if (!cpu_callin_map[cpu]) {
 426                 printk("Processor %u is stuck.\n", cpu);
 427                 return -ENOENT;
 428         }
 429
 430         printk("Processor %u found.\n", cpu);
 431
 432         if (smp_ops->give_timebase)
 433                 smp_ops->give_timebase();
 434
 435         /* Wait until cpu puts itself in the online map */
 436         while (!cpu_online(cpu))
 437                 cpu_relax();
 438
 439         return 0;
 440 }
 441
 442 /* Return the value of the reg property corresponding to the given
 443  * logical cpu.
 444  */
 445 int cpu_to_core_id(int cpu)
 446 {
 447         struct device_node *np;
 448         const int *reg;
 449         int id = -1;
 450
 451         np = of_get_cpu_node(cpu, NULL);
 452         if (!np)
 453                 goto out;
 454
 455         reg = of_get_property(np, "reg", NULL);
 456         if (!reg)
 457                 goto out;
 458
 459         id = *reg;
 460 out:
 461         of_node_put(np);
 462         return id;
 463 }
 464
 465 /* Must be called when no change can occur to cpu_present_map,
 466  * i.e. during cpu online or offline.
 467  */
 468 static struct device_node *cpu_to_l2cache(int cpu)
 469 {
 470         struct device_node *np;
 471         struct device_node *cache;
 472
 473         if (!cpu_present(cpu))
 474                 return NULL;
 475
 476         np = of_get_cpu_node(cpu, NULL);
 477         if (np == NULL)
 478                 return NULL;
 479
 480         cache = of_find_next_cache_node(np);
 481
 482         of_node_put(np);
 483
 484         return cache;
 485 }
 486
 487 /* Activate a secondary processor. */
 488 int __devinit start_secondary(void *unused)
 489 {
 490         unsigned int cpu = smp_processor_id();
 491         struct device_node *l2_cache;
 492         int i, base;
 493
 494         atomic_inc(&init_mm.mm_count);
 495         current->active_mm = &init_mm;
 496
 497         smp_store_cpu_info(cpu);
 498         set_dec(tb_ticks_per_jiffy);
 499         preempt_disable();
 500         cpu_callin_map[cpu] = 1;
 501
 502         if (smp_ops->setup_cpu)
 503                 smp_ops->setup_cpu(cpu);
 504         if (smp_ops->take_timebase)
 505                 smp_ops->take_timebase();
 506
 507         if (system_state > SYSTEM_BOOTING)
 508                 snapshot_timebase();
 509
 510         secondary_cpu_time_init();
 511
 512         ipi_call_lock();
 513         notify_cpu_starting(cpu);
 514         set_cpu_online(cpu, true);
 515         /* Update sibling maps */
 516         base = cpu_first_thread_in_core(cpu);
 517         for (i = 0; i < threads_per_core; i++) {
 518                 if (cpu_is_offline(base + i))
 519                         continue;
 520                 cpu_set(cpu, per_cpu(cpu_sibling_map, base + i));
 521                 cpu_set(base + i, per_cpu(cpu_sibling_map, cpu));
 522
 523                 /* cpu_core_map should be a superset of
 524                  * cpu_sibling_map even if we don't have cache
 525                  * information, so update the former here, too.
 526                  */
 527                 cpu_set(cpu, per_cpu(cpu_core_map, base +i));
 528                 cpu_set(base + i, per_cpu(cpu_core_map, cpu));
 529         }
 530         l2_cache = cpu_to_l2cache(cpu);
 531         for_each_online_cpu(i) {
 532                 struct device_node *np = cpu_to_l2cache(i);
 533                 if (!np)
 534                         continue;
 535                 if (np == l2_cache) {
 536                         cpu_set(cpu, per_cpu(cpu_core_map, i));
 537                         cpu_set(i, per_cpu(cpu_core_map, cpu));
 538                 }
 539                 of_node_put(np);
 540         }
 541         of_node_put(l2_cache);
 542         ipi_call_unlock();
 543
 544         local_irq_enable();
 545
 546         cpu_idle();
 547         return 0;
 548 }
 549
 550 int setup_profiling_timer(unsigned int multiplier)
 551 {
 552         return 0;
 553 }
 554
 555 void __init smp_cpus_done(unsigned int max_cpus)
 556 {
 557         cpumask_t old_mask;
 558
 559         /* We want the setup_cpu() here to be called from CPU 0, but our
 560          * init thread may have been "borrowed" by another CPU in the meantime
 561          * se we pin us down to CPU 0 for a short while
 562          */
 563         old_mask = current->cpus_allowed;
 564         set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
 565
 566         if (smp_ops && smp_ops->setup_cpu)
 567                 smp_ops->setup_cpu(boot_cpuid);
 568
 569         set_cpus_allowed(current, old_mask);
 570
 571         snapshot_timebases();
 572
 573         dump_numa_cpu_topology();
 574 }
 575
 576 #ifdef CONFIG_HOTPLUG_CPU
 577 int __cpu_disable(void)
 578 {
 579         struct device_node *l2_cache;
 580         int cpu = smp_processor_id();
 581         int base, i;
 582         int err;
 583
 584         if (!smp_ops->cpu_disable)
 585                 return -ENOSYS;
 586
 587         err = smp_ops->cpu_disable();
 588         if (err)
 589                 return err;
 590
 591         /* Update sibling maps */
 592         base = cpu_first_thread_in_core(cpu);
 593         for (i = 0; i < threads_per_core; i++) {
 594                 cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i));
 595                 cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu));
 596                 cpu_clear(cpu, per_cpu(cpu_core_map, base +i));
 597                 cpu_clear(base + i, per_cpu(cpu_core_map, cpu));
 598         }
 599
 600         l2_cache = cpu_to_l2cache(cpu);
 601         for_each_present_cpu(i) {
 602                 struct device_node *np = cpu_to_l2cache(i);
 603                 if (!np)
 604                         continue;
 605                 if (np == l2_cache) {
 606                         cpu_clear(cpu, per_cpu(cpu_core_map, i));
 607                         cpu_clear(i, per_cpu(cpu_core_map, cpu));
 608                 }
 609                 of_node_put(np);
 610         }
 611         of_node_put(l2_cache);
 612
 613
 614         return 0;
 615 }
 616
 617 void __cpu_die(unsigned int cpu)
 618 {
 619         if (smp_ops->cpu_die)
 620                 smp_ops->cpu_die(cpu);
 621 }
 622 #endif