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 cpumask_t cpu_possible_map = CPU_MASK_NONE;
  63 cpumask_t cpu_online_map = CPU_MASK_NONE;
  64 DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE;
  65 DEFINE_PER_CPU(cpumask_t, cpu_core_map) = CPU_MASK_NONE;
  66
  67 EXPORT_SYMBOL(cpu_online_map);
  68 EXPORT_SYMBOL(cpu_possible_map);
  69 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
  70 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
  71
  72 /* SMP operations for this machine */
  73 struct smp_ops_t *smp_ops;
  74
  75 static volatile unsigned int cpu_callin_map[NR_CPUS];
  76
  77 int smt_enabled_at_boot = 1;
  78
  79 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
  80
  81 #ifdef CONFIG_PPC64
  82 void __devinit smp_generic_kick_cpu(int nr)
  83 {
  84         BUG_ON(nr < 0 || nr >= NR_CPUS);
  85
  86         /*
  87          * The processor is currently spinning, waiting for the
  88          * cpu_start field to become non-zero After we set cpu_start,
  89          * the processor will continue on to secondary_start
  90          */
  91         paca[nr].cpu_start = 1;
  92         smp_mb();
  93 }
  94 #endif
  95
  96 void smp_message_recv(int msg)
  97 {
  98         switch(msg) {
  99         case PPC_MSG_CALL_FUNCTION:
 100                 generic_smp_call_function_interrupt();
 101                 break;
 102         case PPC_MSG_RESCHEDULE:
 103                 /* we notice need_resched on exit */
 104                 break;
 105         case PPC_MSG_CALL_FUNC_SINGLE:
 106                 generic_smp_call_function_single_interrupt();
 107                 break;
 108         case PPC_MSG_DEBUGGER_BREAK:
 109                 if (crash_ipi_function_ptr) {
 110                         crash_ipi_function_ptr(get_irq_regs());
 111                         break;
 112                 }
 113 #ifdef CONFIG_DEBUGGER
 114                 debugger_ipi(get_irq_regs());
 115                 break;
 116 #endif /* CONFIG_DEBUGGER */
 117                 /* FALLTHROUGH */
 118         default:
 119                 printk("SMP %d: smp_message_recv(): unknown msg %d\n",
 120                        smp_processor_id(), msg);
 121                 break;
 122         }
 123 }
 124
 125 static irqreturn_t call_function_action(int irq, void *data)
 126 {
 127         generic_smp_call_function_interrupt();
 128         return IRQ_HANDLED;
 129 }
 130
 131 static irqreturn_t reschedule_action(int irq, void *data)
 132 {
 133         /* we just need the return path side effect of checking need_resched */
 134         return IRQ_HANDLED;
 135 }
 136
 137 static irqreturn_t call_function_single_action(int irq, void *data)
 138 {
 139         generic_smp_call_function_single_interrupt();
 140         return IRQ_HANDLED;
 141 }
 142
 143 static irqreturn_t debug_ipi_action(int irq, void *data)
 144 {
 145         smp_message_recv(PPC_MSG_DEBUGGER_BREAK);
 146         return IRQ_HANDLED;
 147 }
 148
 149 static irq_handler_t smp_ipi_action[] = {
 150         [PPC_MSG_CALL_FUNCTION] =  call_function_action,
 151         [PPC_MSG_RESCHEDULE] = reschedule_action,
 152         [PPC_MSG_CALL_FUNC_SINGLE] = call_function_single_action,
 153         [PPC_MSG_DEBUGGER_BREAK] = debug_ipi_action,
 154 };
 155
 156 const char *smp_ipi_name[] = {
 157         [PPC_MSG_CALL_FUNCTION] =  "ipi call function",
 158         [PPC_MSG_RESCHEDULE] = "ipi reschedule",
 159         [PPC_MSG_CALL_FUNC_SINGLE] = "ipi call function single",
 160         [PPC_MSG_DEBUGGER_BREAK] = "ipi debugger",
 161 };
 162
 163 /* optional function to request ipi, for controllers with >= 4 ipis */
 164 int smp_request_message_ipi(int virq, int msg)
 165 {
 166         int err;
 167
 168         if (msg < 0 || msg > PPC_MSG_DEBUGGER_BREAK) {
 169                 return -EINVAL;
 170         }
 171 #if !defined(CONFIG_DEBUGGER) && !defined(CONFIG_KEXEC)
 172         if (msg == PPC_MSG_DEBUGGER_BREAK) {
 173                 return 1;
 174         }
 175 #endif
 176         err = request_irq(virq, smp_ipi_action[msg], IRQF_DISABLED|IRQF_PERCPU,
 177                           smp_ipi_name[msg], 0);
 178         WARN(err < 0, "unable to request_irq %d for %s (rc %d)\n",
 179                 virq, smp_ipi_name[msg], err);
 180
 181         return err;
 182 }
 183
 184 void smp_send_reschedule(int cpu)
 185 {
 186         if (likely(smp_ops))
 187                 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
 188 }
 189
 190 void arch_send_call_function_single_ipi(int cpu)
 191 {
 192         smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
 193 }
 194
 195 void arch_send_call_function_ipi(cpumask_t mask)
 196 {
 197         unsigned int cpu;
 198
 199         for_each_cpu_mask(cpu, mask)
 200                 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);
 201 }
 202
 203 #ifdef CONFIG_DEBUGGER
 204 void smp_send_debugger_break(int cpu)
 205 {
 206         if (likely(smp_ops))
 207                 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 208 }
 209 #endif
 210
 211 #ifdef CONFIG_KEXEC
 212 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 213 {
 214         crash_ipi_function_ptr = crash_ipi_callback;
 215         if (crash_ipi_callback && smp_ops) {
 216                 mb();
 217                 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
 218         }
 219 }
 220 #endif
 221
 222 static void stop_this_cpu(void *dummy)
 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(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                 max_cpus = smp_ops->probe();
 276         else
 277                 max_cpus = 1;
 278
 279         smp_space_timers(max_cpus);
 280
 281         for_each_possible_cpu(cpu)
 282                 if (cpu != boot_cpuid)
 283                         smp_create_idle(cpu);
 284 }
 285
 286 void __devinit smp_prepare_boot_cpu(void)
 287 {
 288         BUG_ON(smp_processor_id() != boot_cpuid);
 289
 290         cpu_set(boot_cpuid, cpu_online_map);
 291         cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid));
 292         cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid));
 293 #ifdef CONFIG_PPC64
 294         paca[boot_cpuid].__current = current;
 295 #endif
 296         current_set[boot_cpuid] = task_thread_info(current);
 297 }
 298
 299 #ifdef CONFIG_HOTPLUG_CPU
 300 /* State of each CPU during hotplug phases */
 301 DEFINE_PER_CPU(int, cpu_state) = { 0 };
 302
 303 int generic_cpu_disable(void)
 304 {
 305         unsigned int cpu = smp_processor_id();
 306
 307         if (cpu == boot_cpuid)
 308                 return -EBUSY;
 309
 310         cpu_clear(cpu, cpu_online_map);
 311 #ifdef CONFIG_PPC64
 312         vdso_data->processorCount--;
 313         fixup_irqs(cpu_online_map);
 314 #endif
 315         return 0;
 316 }
 317
 318 int generic_cpu_enable(unsigned int cpu)
 319 {
 320         /* Do the normal bootup if we haven't
 321          * already bootstrapped. */
 322         if (system_state != SYSTEM_RUNNING)
 323                 return -ENOSYS;
 324
 325         /* get the target out of it's holding state */
 326         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 327         smp_wmb();
 328
 329         while (!cpu_online(cpu))
 330                 cpu_relax();
 331
 332 #ifdef CONFIG_PPC64
 333         fixup_irqs(cpu_online_map);
 334         /* counter the irq disable in fixup_irqs */
 335         local_irq_enable();
 336 #endif
 337         return 0;
 338 }
 339
 340 void generic_cpu_die(unsigned int cpu)
 341 {
 342         int i;
 343
 344         for (i = 0; i < 100; i++) {
 345                 smp_rmb();
 346                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 347                         return;
 348                 msleep(100);
 349         }
 350         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 351 }
 352
 353 void generic_mach_cpu_die(void)
 354 {
 355         unsigned int cpu;
 356
 357         local_irq_disable();
 358         cpu = smp_processor_id();
 359         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 360         __get_cpu_var(cpu_state) = CPU_DEAD;
 361         smp_wmb();
 362         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 363                 cpu_relax();
 364         cpu_set(cpu, cpu_online_map);
 365         local_irq_enable();
 366 }
 367 #endif
 368
 369 static int __devinit cpu_enable(unsigned int cpu)
 370 {
 371         if (smp_ops && smp_ops->cpu_enable)
 372                 return smp_ops->cpu_enable(cpu);
 373
 374         return -ENOSYS;
 375 }
 376
 377 int __cpuinit __cpu_up(unsigned int cpu)
 378 {
 379         int c;
 380
 381         secondary_ti = current_set[cpu];
 382         if (!cpu_enable(cpu))
 383                 return 0;
 384
 385         if (smp_ops == NULL ||
 386             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 387                 return -EINVAL;
 388
 389         /* Make sure callin-map entry is 0 (can be leftover a CPU
 390          * hotplug
 391          */
 392         cpu_callin_map[cpu] = 0;
 393
 394         /* The information for processor bringup must
 395          * be written out to main store before we release
 396          * the processor.
 397          */
 398         smp_mb();
 399
 400         /* wake up cpus */
 401         DBG("smp: kicking cpu %d\n", cpu);
 402         smp_ops->kick_cpu(cpu);
 403
 404         /*
 405          * wait to see if the cpu made a callin (is actually up).
 406          * use this value that I found through experimentation.
 407          * -- Cort
 408          */
 409         if (system_state < SYSTEM_RUNNING)
 410                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
 411                         udelay(100);
 412 #ifdef CONFIG_HOTPLUG_CPU
 413         else
 414                 /*
 415                  * CPUs can take much longer to come up in the
 416                  * hotplug case.  Wait five seconds.
 417                  */
 418                 for (c = 25; c && !cpu_callin_map[cpu]; c--) {
 419                         msleep(200);
 420                 }
 421 #endif
 422
 423         if (!cpu_callin_map[cpu]) {
 424                 printk("Processor %u is stuck.\n", cpu);
 425                 return -ENOENT;
 426         }
 427
 428         printk("Processor %u found.\n", cpu);
 429
 430         if (smp_ops->give_timebase)
 431                 smp_ops->give_timebase();
 432
 433         /* Wait until cpu puts itself in the online map */
 434         while (!cpu_online(cpu))
 435                 cpu_relax();
 436
 437         return 0;
 438 }
 439
 440 /* Return the value of the reg property corresponding to the given
 441  * logical cpu.
 442  */
 443 int cpu_to_core_id(int cpu)
 444 {
 445         struct device_node *np;
 446         const int *reg;
 447         int id = -1;
 448
 449         np = of_get_cpu_node(cpu, NULL);
 450         if (!np)
 451                 goto out;
 452
 453         reg = of_get_property(np, "reg", NULL);
 454         if (!reg)
 455                 goto out;
 456
 457         id = *reg;
 458 out:
 459         of_node_put(np);
 460         return id;
 461 }
 462
 463 /* Must be called when no change can occur to cpu_present_map,
 464  * i.e. during cpu online or offline.
 465  */
 466 static struct device_node *cpu_to_l2cache(int cpu)
 467 {
 468         struct device_node *np;
 469         struct device_node *cache;
 470
 471         if (!cpu_present(cpu))
 472                 return NULL;
 473
 474         np = of_get_cpu_node(cpu, NULL);
 475         if (np == NULL)
 476                 return NULL;
 477
 478         cache = of_find_next_cache_node(np);
 479
 480         of_node_put(np);
 481
 482         return cache;
 483 }
 484
 485 /* Activate a secondary processor. */
 486 int __devinit start_secondary(void *unused)
 487 {
 488         unsigned int cpu = smp_processor_id();
 489         struct device_node *l2_cache;
 490         int i, base;
 491
 492         atomic_inc(&init_mm.mm_count);
 493         current->active_mm = &init_mm;
 494
 495         smp_store_cpu_info(cpu);
 496         set_dec(tb_ticks_per_jiffy);
 497         preempt_disable();
 498         cpu_callin_map[cpu] = 1;
 499
 500         smp_ops->setup_cpu(cpu);
 501         if (smp_ops->take_timebase)
 502                 smp_ops->take_timebase();
 503
 504         if (system_state > SYSTEM_BOOTING)
 505                 snapshot_timebase();
 506
 507         secondary_cpu_time_init();
 508
 509         ipi_call_lock();
 510         notify_cpu_starting(cpu);
 511         cpu_set(cpu, cpu_online_map);
 512         /* Update sibling maps */
 513         base = cpu_first_thread_in_core(cpu);
 514         for (i = 0; i < threads_per_core; i++) {
 515                 if (cpu_is_offline(base + i))
 516                         continue;
 517                 cpu_set(cpu, per_cpu(cpu_sibling_map, base + i));
 518                 cpu_set(base + i, per_cpu(cpu_sibling_map, cpu));
 519
 520                 /* cpu_core_map should be a superset of
 521                  * cpu_sibling_map even if we don't have cache
 522                  * information, so update the former here, too.
 523                  */
 524                 cpu_set(cpu, per_cpu(cpu_core_map, base +i));
 525                 cpu_set(base + i, per_cpu(cpu_core_map, cpu));
 526         }
 527         l2_cache = cpu_to_l2cache(cpu);
 528         for_each_online_cpu(i) {
 529                 struct device_node *np = cpu_to_l2cache(i);
 530                 if (!np)
 531                         continue;
 532                 if (np == l2_cache) {
 533                         cpu_set(cpu, per_cpu(cpu_core_map, i));
 534                         cpu_set(i, per_cpu(cpu_core_map, cpu));
 535                 }
 536                 of_node_put(np);
 537         }
 538         of_node_put(l2_cache);
 539         ipi_call_unlock();
 540
 541         local_irq_enable();
 542
 543         cpu_idle();
 544         return 0;
 545 }
 546
 547 int setup_profiling_timer(unsigned int multiplier)
 548 {
 549         return 0;
 550 }
 551
 552 void __init smp_cpus_done(unsigned int max_cpus)
 553 {
 554         cpumask_t old_mask;
 555
 556         /* We want the setup_cpu() here to be called from CPU 0, but our
 557          * init thread may have been "borrowed" by another CPU in the meantime
 558          * se we pin us down to CPU 0 for a short while
 559          */
 560         old_mask = current->cpus_allowed;
 561         set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
 562
 563         if (smp_ops)
 564                 smp_ops->setup_cpu(boot_cpuid);
 565
 566         set_cpus_allowed(current, old_mask);
 567
 568         snapshot_timebases();
 569
 570         dump_numa_cpu_topology();
 571 }
 572
 573 #ifdef CONFIG_HOTPLUG_CPU
 574 int __cpu_disable(void)
 575 {
 576         struct device_node *l2_cache;
 577         int cpu = smp_processor_id();
 578         int base, i;
 579         int err;
 580
 581         if (!smp_ops->cpu_disable)
 582                 return -ENOSYS;
 583
 584         err = smp_ops->cpu_disable();
 585         if (err)
 586                 return err;
 587
 588         /* Update sibling maps */
 589         base = cpu_first_thread_in_core(cpu);
 590         for (i = 0; i < threads_per_core; i++) {
 591                 cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i));
 592                 cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu));
 593                 cpu_clear(cpu, per_cpu(cpu_core_map, base +i));
 594                 cpu_clear(base + i, per_cpu(cpu_core_map, cpu));
 595         }
 596
 597         l2_cache = cpu_to_l2cache(cpu);
 598         for_each_present_cpu(i) {
 599                 struct device_node *np = cpu_to_l2cache(i);
 600                 if (!np)
 601                         continue;
 602                 if (np == l2_cache) {
 603                         cpu_clear(cpu, per_cpu(cpu_core_map, i));
 604                         cpu_clear(i, per_cpu(cpu_core_map, cpu));
 605                 }
 606                 of_node_put(np);
 607         }
 608         of_node_put(l2_cache);
 609
 610
 611         return 0;
 612 }
 613
 614 void __cpu_die(unsigned int cpu)
 615 {
 616         if (smp_ops->cpu_die)
 617                 smp_ops->cpu_die(cpu);
 618 }
 619 #endif