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/cputable.h>
  45 #include <asm/system.h>
  46 #include <asm/mpic.h>
  47 #include <asm/vdso_datapage.h>
  48 #ifdef CONFIG_PPC64
  49 #include <asm/paca.h>
  50 #endif
  51
  52 #ifdef DEBUG
  53 #include <asm/udbg.h>
  54 #define DBG(fmt...) udbg_printf(fmt)
  55 #else
  56 #define DBG(fmt...)
  57 #endif
  58
  59 int smp_hw_index[NR_CPUS];
  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 cpumask_t cpu_sibling_map[NR_CPUS] = { [0 ... NR_CPUS-1] = CPU_MASK_NONE };
  65
  66 EXPORT_SYMBOL(cpu_online_map);
  67 EXPORT_SYMBOL(cpu_possible_map);
  68 EXPORT_SYMBOL(cpu_sibling_map);
  69
  70 /* SMP operations for this machine */
  71 struct smp_ops_t *smp_ops;
  72
  73 static volatile unsigned int cpu_callin_map[NR_CPUS];
  74
  75 void smp_call_function_interrupt(void);
  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                 smp_call_function_interrupt();
 101                 break;
 102         case PPC_MSG_RESCHEDULE:
 103                 /* XXX Do we have to do this? */
 104                 set_need_resched();
 105                 break;
 106         case PPC_MSG_DEBUGGER_BREAK:
 107                 if (crash_ipi_function_ptr) {
 108                         crash_ipi_function_ptr(get_irq_regs());
 109                         break;
 110                 }
 111 #ifdef CONFIG_DEBUGGER
 112                 debugger_ipi(get_irq_regs());
 113                 break;
 114 #endif /* CONFIG_DEBUGGER */
 115                 /* FALLTHROUGH */
 116         default:
 117                 printk("SMP %d: smp_message_recv(): unknown msg %d\n",
 118                        smp_processor_id(), msg);
 119                 break;
 120         }
 121 }
 122
 123 void smp_send_reschedule(int cpu)
 124 {
 125         if (likely(smp_ops))
 126                 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
 127 }
 128
 129 #ifdef CONFIG_DEBUGGER
 130 void smp_send_debugger_break(int cpu)
 131 {
 132         if (likely(smp_ops))
 133                 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 134 }
 135 #endif
 136
 137 #ifdef CONFIG_KEXEC
 138 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 139 {
 140         crash_ipi_function_ptr = crash_ipi_callback;
 141         if (crash_ipi_callback && smp_ops) {
 142                 mb();
 143                 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
 144         }
 145 }
 146 #endif
 147
 148 static void stop_this_cpu(void *dummy)
 149 {
 150         local_irq_disable();
 151         while (1)
 152                 ;
 153 }
 154
 155 /*
 156  * Structure and data for smp_call_function(). This is designed to minimise
 157  * static memory requirements. It also looks cleaner.
 158  * Stolen from the i386 version.
 159  */
 160 static  __cacheline_aligned_in_smp DEFINE_SPINLOCK(call_lock);
 161
 162 static struct call_data_struct {
 163         void (*func) (void *info);
 164         void *info;
 165         atomic_t started;
 166         atomic_t finished;
 167         int wait;
 168 } *call_data;
 169
 170 /* delay of at least 8 seconds */
 171 #define SMP_CALL_TIMEOUT        8
 172
 173 /*
 174  * These functions send a 'generic call function' IPI to other online
 175  * CPUS in the system.
 176  *
 177  * [SUMMARY] Run a function on other CPUs.
 178  * <func> The function to run. This must be fast and non-blocking.
 179  * <info> An arbitrary pointer to pass to the function.
 180  * <nonatomic> currently unused.
 181  * <wait> If true, wait (atomically) until function has completed on other CPUs.
 182  * [RETURNS] 0 on success, else a negative status code. Does not return until
 183  * remote CPUs are nearly ready to execute <<func>> or are or have executed.
 184  *
 185  * You must not call this function with disabled interrupts or from a
 186  * hardware interrupt handler or from a bottom half handler.
 187  */
 188 int smp_call_function_map(void (*func) (void *info), void *info, int nonatomic,
 189                         int wait, cpumask_t map)
 190 {
 191         struct call_data_struct data;
 192         int ret = -1, num_cpus;
 193         int cpu;
 194         u64 timeout;
 195
 196         if (unlikely(smp_ops == NULL))
 197                 return ret;
 198
 199         data.func = func;
 200         data.info = info;
 201         atomic_set(&data.started, 0);
 202         data.wait = wait;
 203         if (wait)
 204                 atomic_set(&data.finished, 0);
 205
 206         spin_lock(&call_lock);
 207
 208         /* remove 'self' from the map */
 209         if (cpu_isset(smp_processor_id(), map))
 210                 cpu_clear(smp_processor_id(), map);
 211
 212         /* sanity check the map, remove any non-online processors. */
 213         cpus_and(map, map, cpu_online_map);
 214
 215         num_cpus = cpus_weight(map);
 216         if (!num_cpus)
 217                 goto done;
 218
 219         call_data = &data;
 220         smp_wmb();
 221         /* Send a message to all CPUs in the map */
 222         for_each_cpu_mask(cpu, map)
 223                 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);
 224
 225         timeout = get_tb() + (u64) SMP_CALL_TIMEOUT * tb_ticks_per_sec;
 226
 227         /* Wait for indication that they have received the message */
 228         while (atomic_read(&data.started) != num_cpus) {
 229                 HMT_low();
 230                 if (get_tb() >= timeout) {
 231                         printk("smp_call_function on cpu %d: other cpus not "
 232                                 "responding (%d)\n", smp_processor_id(),
 233                                 atomic_read(&data.started));
 234                         debugger(NULL);
 235                         goto out;
 236                 }
 237         }
 238
 239         /* optionally wait for the CPUs to complete */
 240         if (wait) {
 241                 while (atomic_read(&data.finished) != num_cpus) {
 242                         HMT_low();
 243                         if (get_tb() >= timeout) {
 244                                 printk("smp_call_function on cpu %d: other "
 245                                         "cpus not finishing (%d/%d)\n",
 246                                         smp_processor_id(),
 247                                         atomic_read(&data.finished),
 248                                         atomic_read(&data.started));
 249                                 debugger(NULL);
 250                                 goto out;
 251                         }
 252                 }
 253         }
 254
 255  done:
 256         ret = 0;
 257
 258  out:
 259         call_data = NULL;
 260         HMT_medium();
 261         spin_unlock(&call_lock);
 262         return ret;
 263 }
 264
 265 static int __smp_call_function(void (*func)(void *info), void *info,
 266                                int nonatomic, int wait)
 267 {
 268         return smp_call_function_map(func,info,nonatomic,wait,cpu_online_map);
 269 }
 270
 271 int smp_call_function(void (*func) (void *info), void *info, int nonatomic,
 272                         int wait)
 273 {
 274         /* Can deadlock when called with interrupts disabled */
 275         WARN_ON(irqs_disabled());
 276
 277         return __smp_call_function(func, info, nonatomic, wait);
 278 }
 279 EXPORT_SYMBOL(smp_call_function);
 280
 281 int smp_call_function_single(int cpu, void (*func) (void *info), void *info, int nonatomic,
 282                         int wait)
 283 {
 284         cpumask_t map = CPU_MASK_NONE;
 285         int ret = 0;
 286
 287         /* Can deadlock when called with interrupts disabled */
 288         WARN_ON(irqs_disabled());
 289
 290         if (!cpu_online(cpu))
 291                 return -EINVAL;
 292
 293         cpu_set(cpu, map);
 294         if (cpu != get_cpu())
 295                 ret = smp_call_function_map(func,info,nonatomic,wait,map);
 296         else {
 297                 local_irq_disable();
 298                 func(info);
 299                 local_irq_enable();
 300         }
 301         put_cpu();
 302         return ret;
 303 }
 304 EXPORT_SYMBOL(smp_call_function_single);
 305
 306 void smp_send_stop(void)
 307 {
 308         __smp_call_function(stop_this_cpu, NULL, 1, 0);
 309 }
 310
 311 void smp_call_function_interrupt(void)
 312 {
 313         void (*func) (void *info);
 314         void *info;
 315         int wait;
 316
 317         /* call_data will be NULL if the sender timed out while
 318          * waiting on us to receive the call.
 319          */
 320         if (!call_data)
 321                 return;
 322
 323         func = call_data->func;
 324         info = call_data->info;
 325         wait = call_data->wait;
 326
 327         if (!wait)
 328                 smp_mb__before_atomic_inc();
 329
 330         /*
 331          * Notify initiating CPU that I've grabbed the data and am
 332          * about to execute the function
 333          */
 334         atomic_inc(&call_data->started);
 335         /*
 336          * At this point the info structure may be out of scope unless wait==1
 337          */
 338         (*func)(info);
 339         if (wait) {
 340                 smp_mb__before_atomic_inc();
 341                 atomic_inc(&call_data->finished);
 342         }
 343 }
 344
 345 extern struct gettimeofday_struct do_gtod;
 346
 347 struct thread_info *current_set[NR_CPUS];
 348
 349 DECLARE_PER_CPU(unsigned int, pvr);
 350
 351 static void __devinit smp_store_cpu_info(int id)
 352 {
 353         per_cpu(pvr, id) = mfspr(SPRN_PVR);
 354 }
 355
 356 static void __init smp_create_idle(unsigned int cpu)
 357 {
 358         struct task_struct *p;
 359
 360         /* create a process for the processor */
 361         p = fork_idle(cpu);
 362         if (IS_ERR(p))
 363                 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
 364 #ifdef CONFIG_PPC64
 365         paca[cpu].__current = p;
 366 #endif
 367         current_set[cpu] = task_thread_info(p);
 368         task_thread_info(p)->cpu = cpu;
 369 }
 370
 371 void __init smp_prepare_cpus(unsigned int max_cpus)
 372 {
 373         unsigned int cpu;
 374
 375         DBG("smp_prepare_cpus\n");
 376
 377         /*
 378          * setup_cpu may need to be called on the boot cpu. We havent
 379          * spun any cpus up but lets be paranoid.
 380          */
 381         BUG_ON(boot_cpuid != smp_processor_id());
 382
 383         /* Fixup boot cpu */
 384         smp_store_cpu_info(boot_cpuid);
 385         cpu_callin_map[boot_cpuid] = 1;
 386
 387         if (smp_ops)
 388                 max_cpus = smp_ops->probe();
 389         else
 390                 max_cpus = 1;
 391
 392         smp_space_timers(max_cpus);
 393
 394         for_each_possible_cpu(cpu)
 395                 if (cpu != boot_cpuid)
 396                         smp_create_idle(cpu);
 397 }
 398
 399 void __devinit smp_prepare_boot_cpu(void)
 400 {
 401         BUG_ON(smp_processor_id() != boot_cpuid);
 402
 403         cpu_set(boot_cpuid, cpu_online_map);
 404 #ifdef CONFIG_PPC64
 405         paca[boot_cpuid].__current = current;
 406 #endif
 407         current_set[boot_cpuid] = task_thread_info(current);
 408 }
 409
 410 #ifdef CONFIG_HOTPLUG_CPU
 411 /* State of each CPU during hotplug phases */
 412 DEFINE_PER_CPU(int, cpu_state) = { 0 };
 413
 414 int generic_cpu_disable(void)
 415 {
 416         unsigned int cpu = smp_processor_id();
 417
 418         if (cpu == boot_cpuid)
 419                 return -EBUSY;
 420
 421         cpu_clear(cpu, cpu_online_map);
 422 #ifdef CONFIG_PPC64
 423         vdso_data->processorCount--;
 424         fixup_irqs(cpu_online_map);
 425 #endif
 426         return 0;
 427 }
 428
 429 int generic_cpu_enable(unsigned int cpu)
 430 {
 431         /* Do the normal bootup if we haven't
 432          * already bootstrapped. */
 433         if (system_state != SYSTEM_RUNNING)
 434                 return -ENOSYS;
 435
 436         /* get the target out of it's holding state */
 437         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 438         smp_wmb();
 439
 440         while (!cpu_online(cpu))
 441                 cpu_relax();
 442
 443 #ifdef CONFIG_PPC64
 444         fixup_irqs(cpu_online_map);
 445         /* counter the irq disable in fixup_irqs */
 446         local_irq_enable();
 447 #endif
 448         return 0;
 449 }
 450
 451 void generic_cpu_die(unsigned int cpu)
 452 {
 453         int i;
 454
 455         for (i = 0; i < 100; i++) {
 456                 smp_rmb();
 457                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 458                         return;
 459                 msleep(100);
 460         }
 461         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 462 }
 463
 464 void generic_mach_cpu_die(void)
 465 {
 466         unsigned int cpu;
 467
 468         local_irq_disable();
 469         cpu = smp_processor_id();
 470         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 471         __get_cpu_var(cpu_state) = CPU_DEAD;
 472         smp_wmb();
 473         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 474                 cpu_relax();
 475         cpu_set(cpu, cpu_online_map);
 476         local_irq_enable();
 477 }
 478 #endif
 479
 480 static int __devinit cpu_enable(unsigned int cpu)
 481 {
 482         if (smp_ops && smp_ops->cpu_enable)
 483                 return smp_ops->cpu_enable(cpu);
 484
 485         return -ENOSYS;
 486 }
 487
 488 int __cpuinit __cpu_up(unsigned int cpu)
 489 {
 490         int c;
 491
 492         secondary_ti = current_set[cpu];
 493         if (!cpu_enable(cpu))
 494                 return 0;
 495
 496         if (smp_ops == NULL ||
 497             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 498                 return -EINVAL;
 499
 500         /* Make sure callin-map entry is 0 (can be leftover a CPU
 501          * hotplug
 502          */
 503         cpu_callin_map[cpu] = 0;
 504
 505         /* The information for processor bringup must
 506          * be written out to main store before we release
 507          * the processor.
 508          */
 509         smp_mb();
 510
 511         /* wake up cpus */
 512         DBG("smp: kicking cpu %d\n", cpu);
 513         smp_ops->kick_cpu(cpu);
 514
 515         /*
 516          * wait to see if the cpu made a callin (is actually up).
 517          * use this value that I found through experimentation.
 518          * -- Cort
 519          */
 520         if (system_state < SYSTEM_RUNNING)
 521                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
 522                         udelay(100);
 523 #ifdef CONFIG_HOTPLUG_CPU
 524         else
 525                 /*
 526                  * CPUs can take much longer to come up in the
 527                  * hotplug case.  Wait five seconds.
 528                  */
 529                 for (c = 25; c && !cpu_callin_map[cpu]; c--) {
 530                         msleep(200);
 531                 }
 532 #endif
 533
 534         if (!cpu_callin_map[cpu]) {
 535                 printk("Processor %u is stuck.\n", cpu);
 536                 return -ENOENT;
 537         }
 538
 539         printk("Processor %u found.\n", cpu);
 540
 541         if (smp_ops->give_timebase)
 542                 smp_ops->give_timebase();
 543
 544         /* Wait until cpu puts itself in the online map */
 545         while (!cpu_online(cpu))
 546                 cpu_relax();
 547
 548         return 0;
 549 }
 550
 551
 552 /* Activate a secondary processor. */
 553 int __devinit start_secondary(void *unused)
 554 {
 555         unsigned int cpu = smp_processor_id();
 556
 557         atomic_inc(&init_mm.mm_count);
 558         current->active_mm = &init_mm;
 559
 560         smp_store_cpu_info(cpu);
 561         set_dec(tb_ticks_per_jiffy);
 562         preempt_disable();
 563         cpu_callin_map[cpu] = 1;
 564
 565         smp_ops->setup_cpu(cpu);
 566         if (smp_ops->take_timebase)
 567                 smp_ops->take_timebase();
 568
 569         if (system_state > SYSTEM_BOOTING)
 570                 snapshot_timebase();
 571
 572         secondary_cpu_time_init();
 573
 574         spin_lock(&call_lock);
 575         cpu_set(cpu, cpu_online_map);
 576         spin_unlock(&call_lock);
 577
 578         local_irq_enable();
 579
 580         cpu_idle();
 581         return 0;
 582 }
 583
 584 int setup_profiling_timer(unsigned int multiplier)
 585 {
 586         return 0;
 587 }
 588
 589 void __init smp_cpus_done(unsigned int max_cpus)
 590 {
 591         cpumask_t old_mask;
 592
 593         /* We want the setup_cpu() here to be called from CPU 0, but our
 594          * init thread may have been "borrowed" by another CPU in the meantime
 595          * se we pin us down to CPU 0 for a short while
 596          */
 597         old_mask = current->cpus_allowed;
 598         set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
 599
 600         if (smp_ops)
 601                 smp_ops->setup_cpu(boot_cpuid);
 602
 603         set_cpus_allowed(current, old_mask);
 604
 605         snapshot_timebases();
 606
 607         dump_numa_cpu_topology();
 608 }
 609
 610 #ifdef CONFIG_HOTPLUG_CPU
 611 int __cpu_disable(void)
 612 {
 613         if (smp_ops->cpu_disable)
 614                 return smp_ops->cpu_disable();
 615
 616         return -ENOSYS;
 617 }
 618
 619 void __cpu_die(unsigned int cpu)
 620 {
 621         if (smp_ops->cpu_die)
 622                 smp_ops->cpu_die(cpu);
 623 }
 624 #endif