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 #endif
 321         migrate_irqs();
 322         return 0;
 323 }
 324
 325 void generic_cpu_die(unsigned int cpu)
 326 {
 327         int i;
 328
 329         for (i = 0; i < 100; i++) {
 330                 smp_rmb();
 331                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 332                         return;
 333                 msleep(100);
 334         }
 335         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 336 }
 337
 338 void generic_mach_cpu_die(void)
 339 {
 340         unsigned int cpu;
 341
 342         local_irq_disable();
 343         idle_task_exit();
 344         cpu = smp_processor_id();
 345         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 346         __get_cpu_var(cpu_state) = CPU_DEAD;
 347         smp_wmb();
 348         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 349                 cpu_relax();
 350 }
 351 #endif
 352
 353 int __cpuinit __cpu_up(unsigned int cpu)
 354 {
 355         int c;
 356
 357         secondary_ti = current_set[cpu];
 358
 359         if (smp_ops == NULL ||
 360             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 361                 return -EINVAL;
 362
 363         /* Make sure callin-map entry is 0 (can be leftover a CPU
 364          * hotplug
 365          */
 366         cpu_callin_map[cpu] = 0;
 367
 368         /* The information for processor bringup must
 369          * be written out to main store before we release
 370          * the processor.
 371          */
 372         smp_mb();
 373
 374         /* wake up cpus */
 375         DBG("smp: kicking cpu %d\n", cpu);
 376         smp_ops->kick_cpu(cpu);
 377
 378         /*
 379          * wait to see if the cpu made a callin (is actually up).
 380          * use this value that I found through experimentation.
 381          * -- Cort
 382          */
 383         if (system_state < SYSTEM_RUNNING)
 384                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
 385                         udelay(100);
 386 #ifdef CONFIG_HOTPLUG_CPU
 387         else
 388                 /*
 389                  * CPUs can take much longer to come up in the
 390                  * hotplug case.  Wait five seconds.
 391                  */
 392                 for (c = 5000; c && !cpu_callin_map[cpu]; c--)
 393                         msleep(1);
 394 #endif
 395
 396         if (!cpu_callin_map[cpu]) {
 397                 printk(KERN_ERR "Processor %u is stuck.\n", cpu);
 398                 return -ENOENT;
 399         }
 400
 401         DBG("Processor %u found.\n", cpu);
 402
 403         if (smp_ops->give_timebase)
 404                 smp_ops->give_timebase();
 405
 406         /* Wait until cpu puts itself in the online map */
 407         while (!cpu_online(cpu))
 408                 cpu_relax();
 409
 410         return 0;
 411 }
 412
 413 /* Return the value of the reg property corresponding to the given
 414  * logical cpu.
 415  */
 416 int cpu_to_core_id(int cpu)
 417 {
 418         struct device_node *np;
 419         const int *reg;
 420         int id = -1;
 421
 422         np = of_get_cpu_node(cpu, NULL);
 423         if (!np)
 424                 goto out;
 425
 426         reg = of_get_property(np, "reg", NULL);
 427         if (!reg)
 428                 goto out;
 429
 430         id = *reg;
 431 out:
 432         of_node_put(np);
 433         return id;
 434 }
 435
 436 /* Helper routines for cpu to core mapping */
 437 int cpu_core_index_of_thread(int cpu)
 438 {
 439         return cpu >> threads_shift;
 440 }
 441 EXPORT_SYMBOL_GPL(cpu_core_index_of_thread);
 442
 443 int cpu_first_thread_of_core(int core)
 444 {
 445         return core << threads_shift;
 446 }
 447 EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);
 448
 449 /* Must be called when no change can occur to cpu_present_map,
 450  * i.e. during cpu online or offline.
 451  */
 452 static struct device_node *cpu_to_l2cache(int cpu)
 453 {
 454         struct device_node *np;
 455         struct device_node *cache;
 456
 457         if (!cpu_present(cpu))
 458                 return NULL;
 459
 460         np = of_get_cpu_node(cpu, NULL);
 461         if (np == NULL)
 462                 return NULL;
 463
 464         cache = of_find_next_cache_node(np);
 465
 466         of_node_put(np);
 467
 468         return cache;
 469 }
 470
 471 /* Activate a secondary processor. */
 472 void __devinit start_secondary(void *unused)
 473 {
 474         unsigned int cpu = smp_processor_id();
 475         struct device_node *l2_cache;
 476         int i, base;
 477
 478         atomic_inc(&init_mm.mm_count);
 479         current->active_mm = &init_mm;
 480
 481         smp_store_cpu_info(cpu);
 482         set_dec(tb_ticks_per_jiffy);
 483         preempt_disable();
 484         cpu_callin_map[cpu] = 1;
 485
 486         if (smp_ops->setup_cpu)
 487                 smp_ops->setup_cpu(cpu);
 488         if (smp_ops->take_timebase)
 489                 smp_ops->take_timebase();
 490
 491         secondary_cpu_time_init();
 492
 493         ipi_call_lock();
 494         notify_cpu_starting(cpu);
 495         set_cpu_online(cpu, true);
 496         /* Update sibling maps */
 497         base = cpu_first_thread_sibling(cpu);
 498         for (i = 0; i < threads_per_core; i++) {
 499                 if (cpu_is_offline(base + i))
 500                         continue;
 501                 cpumask_set_cpu(cpu, cpu_sibling_mask(base + i));
 502                 cpumask_set_cpu(base + i, cpu_sibling_mask(cpu));
 503
 504                 /* cpu_core_map should be a superset of
 505                  * cpu_sibling_map even if we don't have cache
 506                  * information, so update the former here, too.
 507                  */
 508                 cpumask_set_cpu(cpu, cpu_core_mask(base + i));
 509                 cpumask_set_cpu(base + i, cpu_core_mask(cpu));
 510         }
 511         l2_cache = cpu_to_l2cache(cpu);
 512         for_each_online_cpu(i) {
 513                 struct device_node *np = cpu_to_l2cache(i);
 514                 if (!np)
 515                         continue;
 516                 if (np == l2_cache) {
 517                         cpumask_set_cpu(cpu, cpu_core_mask(i));
 518                         cpumask_set_cpu(i, cpu_core_mask(cpu));
 519                 }
 520                 of_node_put(np);
 521         }
 522         of_node_put(l2_cache);
 523         ipi_call_unlock();
 524
 525         local_irq_enable();
 526
 527         cpu_idle();
 528
 529         BUG();
 530 }
 531
 532 int setup_profiling_timer(unsigned int multiplier)
 533 {
 534         return 0;
 535 }
 536
 537 void __init smp_cpus_done(unsigned int max_cpus)
 538 {
 539         cpumask_var_t old_mask;
 540
 541         /* We want the setup_cpu() here to be called from CPU 0, but our
 542          * init thread may have been "borrowed" by another CPU in the meantime
 543          * se we pin us down to CPU 0 for a short while
 544          */
 545         alloc_cpumask_var(&old_mask, GFP_NOWAIT);
 546         cpumask_copy(old_mask, &current->cpus_allowed);
 547         set_cpus_allowed_ptr(current, cpumask_of(boot_cpuid));
 548
 549         if (smp_ops && smp_ops->setup_cpu)
 550                 smp_ops->setup_cpu(boot_cpuid);
 551
 552         set_cpus_allowed_ptr(current, old_mask);
 553
 554         free_cpumask_var(old_mask);
 555
 556         dump_numa_cpu_topology();
 557 }
 558
 559 int arch_sd_sibling_asym_packing(void)
 560 {
 561         if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
 562                 printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
 563                 return SD_ASYM_PACKING;
 564         }
 565         return 0;
 566 }
 567
 568 #ifdef CONFIG_HOTPLUG_CPU
 569 int __cpu_disable(void)
 570 {
 571         struct device_node *l2_cache;
 572         int cpu = smp_processor_id();
 573         int base, i;
 574         int err;
 575
 576         if (!smp_ops->cpu_disable)
 577                 return -ENOSYS;
 578
 579         err = smp_ops->cpu_disable();
 580         if (err)
 581                 return err;
 582
 583         /* Update sibling maps */
 584         base = cpu_first_thread_sibling(cpu);
 585         for (i = 0; i < threads_per_core; i++) {
 586                 cpumask_clear_cpu(cpu, cpu_sibling_mask(base + i));
 587                 cpumask_clear_cpu(base + i, cpu_sibling_mask(cpu));
 588                 cpumask_clear_cpu(cpu, cpu_core_mask(base + i));
 589                 cpumask_clear_cpu(base + i, cpu_core_mask(cpu));
 590         }
 591
 592         l2_cache = cpu_to_l2cache(cpu);
 593         for_each_present_cpu(i) {
 594                 struct device_node *np = cpu_to_l2cache(i);
 595                 if (!np)
 596                         continue;
 597                 if (np == l2_cache) {
 598                         cpumask_clear_cpu(cpu, cpu_core_mask(i));
 599                         cpumask_clear_cpu(i, cpu_core_mask(cpu));
 600                 }
 601                 of_node_put(np);
 602         }
 603         of_node_put(l2_cache);
 604
 605
 606         return 0;
 607 }
 608
 609 void __cpu_die(unsigned int cpu)
 610 {
 611         if (smp_ops->cpu_die)
 612                 smp_ops->cpu_die(cpu);
 613 }
 614
 615 static DEFINE_MUTEX(powerpc_cpu_hotplug_driver_mutex);
 616
 617 void cpu_hotplug_driver_lock()
 618 {
 619         mutex_lock(&powerpc_cpu_hotplug_driver_mutex);
 620 }
 621
 622 void cpu_hotplug_driver_unlock()
 623 {
 624         mutex_unlock(&powerpc_cpu_hotplug_driver_mutex);
 625 }
 626
 627 void cpu_die(void)
 628 {
 629         if (ppc_md.cpu_die)
 630                 ppc_md.cpu_die();
 631
 632         /* If we return, we re-enter start_secondary */
 633         start_secondary_resume();
 634 }
 635
 636 #endif