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 static volatile unsigned int cpu_callin_map[NR_CPUS];
  72
  73 int smt_enabled_at_boot = 1;
  74
  75 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
  76
  77 #ifdef CONFIG_PPC64
  78 void __devinit smp_generic_kick_cpu(int nr)
  79 {
  80         BUG_ON(nr < 0 || nr >= NR_CPUS);
  81
  82         /*
  83          * The processor is currently spinning, waiting for the
  84          * cpu_start field to become non-zero After we set cpu_start,
  85          * the processor will continue on to secondary_start
  86          */
  87         paca[nr].cpu_start = 1;
  88         smp_mb();
  89 }
  90 #endif
  91
  92 void smp_message_recv(int msg)
  93 {
  94         switch(msg) {
  95         case PPC_MSG_CALL_FUNCTION:
  96                 generic_smp_call_function_interrupt();
  97                 break;
  98         case PPC_MSG_RESCHEDULE:
  99                 /* we notice need_resched on exit */
 100                 break;
 101         case PPC_MSG_CALL_FUNC_SINGLE:
 102                 generic_smp_call_function_single_interrupt();
 103                 break;
 104         case PPC_MSG_DEBUGGER_BREAK:
 105                 if (crash_ipi_function_ptr) {
 106                         crash_ipi_function_ptr(get_irq_regs());
 107                         break;
 108                 }
 109 #ifdef CONFIG_DEBUGGER
 110                 debugger_ipi(get_irq_regs());
 111                 break;
 112 #endif /* CONFIG_DEBUGGER */
 113                 /* FALLTHROUGH */
 114         default:
 115                 printk("SMP %d: smp_message_recv(): unknown msg %d\n",
 116                        smp_processor_id(), msg);
 117                 break;
 118         }
 119 }
 120
 121 static irqreturn_t call_function_action(int irq, void *data)
 122 {
 123         generic_smp_call_function_interrupt();
 124         return IRQ_HANDLED;
 125 }
 126
 127 static irqreturn_t reschedule_action(int irq, void *data)
 128 {
 129         /* we just need the return path side effect of checking need_resched */
 130         return IRQ_HANDLED;
 131 }
 132
 133 static irqreturn_t call_function_single_action(int irq, void *data)
 134 {
 135         generic_smp_call_function_single_interrupt();
 136         return IRQ_HANDLED;
 137 }
 138
 139 static irqreturn_t debug_ipi_action(int irq, void *data)
 140 {
 141         smp_message_recv(PPC_MSG_DEBUGGER_BREAK);
 142         return IRQ_HANDLED;
 143 }
 144
 145 static irq_handler_t smp_ipi_action[] = {
 146         [PPC_MSG_CALL_FUNCTION] =  call_function_action,
 147         [PPC_MSG_RESCHEDULE] = reschedule_action,
 148         [PPC_MSG_CALL_FUNC_SINGLE] = call_function_single_action,
 149         [PPC_MSG_DEBUGGER_BREAK] = debug_ipi_action,
 150 };
 151
 152 const char *smp_ipi_name[] = {
 153         [PPC_MSG_CALL_FUNCTION] =  "ipi call function",
 154         [PPC_MSG_RESCHEDULE] = "ipi reschedule",
 155         [PPC_MSG_CALL_FUNC_SINGLE] = "ipi call function single",
 156         [PPC_MSG_DEBUGGER_BREAK] = "ipi debugger",
 157 };
 158
 159 /* optional function to request ipi, for controllers with >= 4 ipis */
 160 int smp_request_message_ipi(int virq, int msg)
 161 {
 162         int err;
 163
 164         if (msg < 0 || msg > PPC_MSG_DEBUGGER_BREAK) {
 165                 return -EINVAL;
 166         }
 167 #if !defined(CONFIG_DEBUGGER) && !defined(CONFIG_KEXEC)
 168         if (msg == PPC_MSG_DEBUGGER_BREAK) {
 169                 return 1;
 170         }
 171 #endif
 172         err = request_irq(virq, smp_ipi_action[msg], IRQF_DISABLED|IRQF_PERCPU,
 173                           smp_ipi_name[msg], 0);
 174         WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n",
 175                 virq, smp_ipi_name[msg], err);
 176
 177         return err;
 178 }
 179
 180 void smp_send_reschedule(int cpu)
 181 {
 182         if (likely(smp_ops))
 183                 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
 184 }
 185
 186 void arch_send_call_function_single_ipi(int cpu)
 187 {
 188         smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
 189 }
 190
 191 void arch_send_call_function_ipi(cpumask_t mask)
 192 {
 193         unsigned int cpu;
 194
 195         for_each_cpu_mask(cpu, mask)
 196                 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);
 197 }
 198
 199 #ifdef CONFIG_DEBUGGER
 200 void smp_send_debugger_break(int cpu)
 201 {
 202         if (likely(smp_ops))
 203                 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 204 }
 205 #endif
 206
 207 #ifdef CONFIG_KEXEC
 208 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 209 {
 210         crash_ipi_function_ptr = crash_ipi_callback;
 211         if (crash_ipi_callback && smp_ops) {
 212                 mb();
 213                 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
 214         }
 215 }
 216 #endif
 217
 218 static void stop_this_cpu(void *dummy)
 219 {
 220         local_irq_disable();
 221         while (1)
 222                 ;
 223 }
 224
 225 void smp_send_stop(void)
 226 {
 227         smp_call_function(stop_this_cpu, NULL, 0);
 228 }
 229
 230 struct thread_info *current_set[NR_CPUS];
 231
 232 static void __devinit smp_store_cpu_info(int id)
 233 {
 234         per_cpu(pvr, id) = mfspr(SPRN_PVR);
 235 }
 236
 237 static void __init smp_create_idle(unsigned int cpu)
 238 {
 239         struct task_struct *p;
 240
 241         /* create a process for the processor */
 242         p = fork_idle(cpu);
 243         if (IS_ERR(p))
 244                 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
 245 #ifdef CONFIG_PPC64
 246         paca[cpu].__current = p;
 247         paca[cpu].kstack = (unsigned long) task_thread_info(p)
 248                 + THREAD_SIZE - STACK_FRAME_OVERHEAD;
 249 #endif
 250         current_set[cpu] = task_thread_info(p);
 251         task_thread_info(p)->cpu = cpu;
 252 }
 253
 254 void __init smp_prepare_cpus(unsigned int max_cpus)
 255 {
 256         unsigned int cpu;
 257
 258         DBG("smp_prepare_cpus\n");
 259
 260         /*
 261          * setup_cpu may need to be called on the boot cpu. We havent
 262          * spun any cpus up but lets be paranoid.
 263          */
 264         BUG_ON(boot_cpuid != smp_processor_id());
 265
 266         /* Fixup boot cpu */
 267         smp_store_cpu_info(boot_cpuid);
 268         cpu_callin_map[boot_cpuid] = 1;
 269
 270         if (smp_ops)
 271                 max_cpus = smp_ops->probe();
 272         else
 273                 max_cpus = 1;
 274
 275         smp_space_timers(max_cpus);
 276
 277         for_each_possible_cpu(cpu)
 278                 if (cpu != boot_cpuid)
 279                         smp_create_idle(cpu);
 280 }
 281
 282 void __devinit smp_prepare_boot_cpu(void)
 283 {
 284         BUG_ON(smp_processor_id() != boot_cpuid);
 285
 286         cpu_set(boot_cpuid, cpu_online_map);
 287         cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid));
 288         cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid));
 289 #ifdef CONFIG_PPC64
 290         paca[boot_cpuid].__current = current;
 291 #endif
 292         current_set[boot_cpuid] = task_thread_info(current);
 293 }
 294
 295 #ifdef CONFIG_HOTPLUG_CPU
 296 /* State of each CPU during hotplug phases */
 297 DEFINE_PER_CPU(int, cpu_state) = { 0 };
 298
 299 int generic_cpu_disable(void)
 300 {
 301         unsigned int cpu = smp_processor_id();
 302
 303         if (cpu == boot_cpuid)
 304                 return -EBUSY;
 305
 306         cpu_clear(cpu, cpu_online_map);
 307 #ifdef CONFIG_PPC64
 308         vdso_data->processorCount--;
 309         fixup_irqs(cpu_online_map);
 310 #endif
 311         return 0;
 312 }
 313
 314 int generic_cpu_enable(unsigned int cpu)
 315 {
 316         /* Do the normal bootup if we haven't
 317          * already bootstrapped. */
 318         if (system_state != SYSTEM_RUNNING)
 319                 return -ENOSYS;
 320
 321         /* get the target out of it's holding state */
 322         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 323         smp_wmb();
 324
 325         while (!cpu_online(cpu))
 326                 cpu_relax();
 327
 328 #ifdef CONFIG_PPC64
 329         fixup_irqs(cpu_online_map);
 330         /* counter the irq disable in fixup_irqs */
 331         local_irq_enable();
 332 #endif
 333         return 0;
 334 }
 335
 336 void generic_cpu_die(unsigned int cpu)
 337 {
 338         int i;
 339
 340         for (i = 0; i < 100; i++) {
 341                 smp_rmb();
 342                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 343                         return;
 344                 msleep(100);
 345         }
 346         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 347 }
 348
 349 void generic_mach_cpu_die(void)
 350 {
 351         unsigned int cpu;
 352
 353         local_irq_disable();
 354         cpu = smp_processor_id();
 355         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 356         __get_cpu_var(cpu_state) = CPU_DEAD;
 357         smp_wmb();
 358         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 359                 cpu_relax();
 360         cpu_set(cpu, cpu_online_map);
 361         local_irq_enable();
 362 }
 363 #endif
 364
 365 static int __devinit cpu_enable(unsigned int cpu)
 366 {
 367         if (smp_ops && smp_ops->cpu_enable)
 368                 return smp_ops->cpu_enable(cpu);
 369
 370         return -ENOSYS;
 371 }
 372
 373 int __cpuinit __cpu_up(unsigned int cpu)
 374 {
 375         int c;
 376
 377         secondary_ti = current_set[cpu];
 378         if (!cpu_enable(cpu))
 379                 return 0;
 380
 381         if (smp_ops == NULL ||
 382             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 383                 return -EINVAL;
 384
 385         /* Make sure callin-map entry is 0 (can be leftover a CPU
 386          * hotplug
 387          */
 388         cpu_callin_map[cpu] = 0;
 389
 390         /* The information for processor bringup must
 391          * be written out to main store before we release
 392          * the processor.
 393          */
 394         smp_mb();
 395
 396         /* wake up cpus */
 397         DBG("smp: kicking cpu %d\n", cpu);
 398         smp_ops->kick_cpu(cpu);
 399
 400         /*
 401          * wait to see if the cpu made a callin (is actually up).
 402          * use this value that I found through experimentation.
 403          * -- Cort
 404          */
 405         if (system_state < SYSTEM_RUNNING)
 406                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
 407                         udelay(100);
 408 #ifdef CONFIG_HOTPLUG_CPU
 409         else
 410                 /*
 411                  * CPUs can take much longer to come up in the
 412                  * hotplug case.  Wait five seconds.
 413                  */
 414                 for (c = 25; c && !cpu_callin_map[cpu]; c--) {
 415                         msleep(200);
 416                 }
 417 #endif
 418
 419         if (!cpu_callin_map[cpu]) {
 420                 printk("Processor %u is stuck.\n", cpu);
 421                 return -ENOENT;
 422         }
 423
 424         printk("Processor %u found.\n", cpu);
 425
 426         if (smp_ops->give_timebase)
 427                 smp_ops->give_timebase();
 428
 429         /* Wait until cpu puts itself in the online map */
 430         while (!cpu_online(cpu))
 431                 cpu_relax();
 432
 433         return 0;
 434 }
 435
 436 /* Return the value of the reg property corresponding to the given
 437  * logical cpu.
 438  */
 439 int cpu_to_core_id(int cpu)
 440 {
 441         struct device_node *np;
 442         const int *reg;
 443         int id = -1;
 444
 445         np = of_get_cpu_node(cpu, NULL);
 446         if (!np)
 447                 goto out;
 448
 449         reg = of_get_property(np, "reg", NULL);
 450         if (!reg)
 451                 goto out;
 452
 453         id = *reg;
 454 out:
 455         of_node_put(np);
 456         return id;
 457 }
 458
 459 /* Must be called when no change can occur to cpu_present_map,
 460  * i.e. during cpu online or offline.
 461  */
 462 static struct device_node *cpu_to_l2cache(int cpu)
 463 {
 464         struct device_node *np;
 465         struct device_node *cache;
 466
 467         if (!cpu_present(cpu))
 468                 return NULL;
 469
 470         np = of_get_cpu_node(cpu, NULL);
 471         if (np == NULL)
 472                 return NULL;
 473
 474         cache = of_find_next_cache_node(np);
 475
 476         of_node_put(np);
 477
 478         return cache;
 479 }
 480
 481 /* Activate a secondary processor. */
 482 int __devinit start_secondary(void *unused)
 483 {
 484         unsigned int cpu = smp_processor_id();
 485         struct device_node *l2_cache;
 486         int i, base;
 487
 488         atomic_inc(&init_mm.mm_count);
 489         current->active_mm = &init_mm;
 490
 491         smp_store_cpu_info(cpu);
 492         set_dec(tb_ticks_per_jiffy);
 493         preempt_disable();
 494         cpu_callin_map[cpu] = 1;
 495
 496         smp_ops->setup_cpu(cpu);
 497         if (smp_ops->take_timebase)
 498                 smp_ops->take_timebase();
 499
 500         if (system_state > SYSTEM_BOOTING)
 501                 snapshot_timebase();
 502
 503         secondary_cpu_time_init();
 504
 505         ipi_call_lock();
 506         notify_cpu_starting(cpu);
 507         cpu_set(cpu, cpu_online_map);
 508         /* Update sibling maps */
 509         base = cpu_first_thread_in_core(cpu);
 510         for (i = 0; i < threads_per_core; i++) {
 511                 if (cpu_is_offline(base + i))
 512                         continue;
 513                 cpu_set(cpu, per_cpu(cpu_sibling_map, base + i));
 514                 cpu_set(base + i, per_cpu(cpu_sibling_map, cpu));
 515
 516                 /* cpu_core_map should be a superset of
 517                  * cpu_sibling_map even if we don't have cache
 518                  * information, so update the former here, too.
 519                  */
 520                 cpu_set(cpu, per_cpu(cpu_core_map, base +i));
 521                 cpu_set(base + i, per_cpu(cpu_core_map, cpu));
 522         }
 523         l2_cache = cpu_to_l2cache(cpu);
 524         for_each_online_cpu(i) {
 525                 struct device_node *np = cpu_to_l2cache(i);
 526                 if (!np)
 527                         continue;
 528                 if (np == l2_cache) {
 529                         cpu_set(cpu, per_cpu(cpu_core_map, i));
 530                         cpu_set(i, per_cpu(cpu_core_map, cpu));
 531                 }
 532                 of_node_put(np);
 533         }
 534         of_node_put(l2_cache);
 535         ipi_call_unlock();
 536
 537         local_irq_enable();
 538
 539         cpu_idle();
 540         return 0;
 541 }
 542
 543 int setup_profiling_timer(unsigned int multiplier)
 544 {
 545         return 0;
 546 }
 547
 548 void __init smp_cpus_done(unsigned int max_cpus)
 549 {
 550         cpumask_t old_mask;
 551
 552         /* We want the setup_cpu() here to be called from CPU 0, but our
 553          * init thread may have been "borrowed" by another CPU in the meantime
 554          * se we pin us down to CPU 0 for a short while
 555          */
 556         old_mask = current->cpus_allowed;
 557         set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
 558
 559         if (smp_ops)
 560                 smp_ops->setup_cpu(boot_cpuid);
 561
 562         set_cpus_allowed(current, old_mask);
 563
 564         snapshot_timebases();
 565
 566         dump_numa_cpu_topology();
 567 }
 568
 569 #ifdef CONFIG_HOTPLUG_CPU
 570 int __cpu_disable(void)
 571 {
 572         struct device_node *l2_cache;
 573         int cpu = smp_processor_id();
 574         int base, i;
 575         int err;
 576
 577         if (!smp_ops->cpu_disable)
 578                 return -ENOSYS;
 579
 580         err = smp_ops->cpu_disable();
 581         if (err)
 582                 return err;
 583
 584         /* Update sibling maps */
 585         base = cpu_first_thread_in_core(cpu);
 586         for (i = 0; i < threads_per_core; i++) {
 587                 cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i));
 588                 cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu));
 589                 cpu_clear(cpu, per_cpu(cpu_core_map, base +i));
 590                 cpu_clear(base + i, per_cpu(cpu_core_map, cpu));
 591         }
 592
 593         l2_cache = cpu_to_l2cache(cpu);
 594         for_each_present_cpu(i) {
 595                 struct device_node *np = cpu_to_l2cache(i);
 596                 if (!np)
 597                         continue;
 598                 if (np == l2_cache) {
 599                         cpu_clear(cpu, per_cpu(cpu_core_map, i));
 600                         cpu_clear(i, per_cpu(cpu_core_map, cpu));
 601                 }
 602                 of_node_put(np);
 603         }
 604         of_node_put(l2_cache);
 605
 606
 607         return 0;
 608 }
 609
 610 void __cpu_die(unsigned int cpu)
 611 {
 612         if (smp_ops->cpu_die)
 613                 smp_ops->cpu_die(cpu);
 614 }
 615 #endif