arch/ppc64/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/config.h>
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/sched.h>
  24 #include <linux/smp.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/delay.h>
  27 #include <linux/init.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/cache.h>
  30 #include <linux/err.h>
  31 #include <linux/sysdev.h>
  32 #include <linux/cpu.h>
  33 #include <linux/notifier.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/paca.h>
  43 #include <asm/time.h>
  44 #include <asm/machdep.h>
  45 #include <asm/cputable.h>
  46 #include <asm/system.h>
  47 #include <asm/abs_addr.h>
  48 #include <asm/mpic.h>
  49
  50 #ifdef DEBUG
  51 #define DBG(fmt...) udbg_printf(fmt)
  52 #else
  53 #define DBG(fmt...)
  54 #endif
  55
  56 cpumask_t cpu_possible_map = CPU_MASK_NONE;
  57 cpumask_t cpu_online_map = CPU_MASK_NONE;
  58 cpumask_t cpu_sibling_map[NR_CPUS] = { [0 ... NR_CPUS-1] = CPU_MASK_NONE };
  59
  60 EXPORT_SYMBOL(cpu_online_map);
  61 EXPORT_SYMBOL(cpu_possible_map);
  62
  63 struct smp_ops_t *smp_ops;
  64
  65 static volatile unsigned int cpu_callin_map[NR_CPUS];
  66
  67 void smp_call_function_interrupt(void);
  68
  69 int smt_enabled_at_boot = 1;
  70
  71 #ifdef CONFIG_MPIC
  72 int __init smp_mpic_probe(void)
  73 {
  74         int nr_cpus;
  75
  76         DBG("smp_mpic_probe()...\n");
  77
  78         nr_cpus = cpus_weight(cpu_possible_map);
  79
  80         DBG("nr_cpus: %d\n", nr_cpus);
  81
  82         if (nr_cpus > 1)
  83                 mpic_request_ipis();
  84
  85         return nr_cpus;
  86 }
  87
  88 void __devinit smp_mpic_setup_cpu(int cpu)
  89 {
  90         mpic_setup_this_cpu();
  91 }
  92
  93 void __devinit smp_generic_kick_cpu(int nr)
  94 {
  95         BUG_ON(nr < 0 || nr >= NR_CPUS);
  96
  97         /*
  98          * The processor is currently spinning, waiting for the
  99          * cpu_start field to become non-zero After we set cpu_start,
 100          * the processor will continue on to secondary_start
 101          */
 102         paca[nr].cpu_start = 1;
 103         smp_mb();
 104 }
 105
 106 #endif /* CONFIG_MPIC */
 107
 108 void smp_message_recv(int msg, struct pt_regs *regs)
 109 {
 110         switch(msg) {
 111         case PPC_MSG_CALL_FUNCTION:
 112                 smp_call_function_interrupt();
 113                 break;
 114         case PPC_MSG_RESCHEDULE:
 115                 /* XXX Do we have to do this? */
 116                 set_need_resched();
 117                 break;
 118 #if 0
 119         case PPC_MSG_MIGRATE_TASK:
 120                 /* spare */
 121                 break;
 122 #endif
 123 #ifdef CONFIG_DEBUGGER
 124         case PPC_MSG_DEBUGGER_BREAK:
 125                 debugger_ipi(regs);
 126                 break;
 127 #endif
 128         default:
 129                 printk("SMP %d: smp_message_recv(): unknown msg %d\n",
 130                        smp_processor_id(), msg);
 131                 break;
 132         }
 133 }
 134
 135 void smp_send_reschedule(int cpu)
 136 {
 137         smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
 138 }
 139
 140 #ifdef CONFIG_DEBUGGER
 141 void smp_send_debugger_break(int cpu)
 142 {
 143         smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 144 }
 145 #endif
 146
 147 static void stop_this_cpu(void *dummy)
 148 {
 149         local_irq_disable();
 150         while (1)
 151                 ;
 152 }
 153
 154 void smp_send_stop(void)
 155 {
 156         smp_call_function(stop_this_cpu, NULL, 1, 0);
 157 }
 158
 159 /*
 160  * Structure and data for smp_call_function(). This is designed to minimise
 161  * static memory requirements. It also looks cleaner.
 162  * Stolen from the i386 version.
 163  */
 164 static  __cacheline_aligned_in_smp DEFINE_SPINLOCK(call_lock);
 165
 166 static struct call_data_struct {
 167         void (*func) (void *info);
 168         void *info;
 169         atomic_t started;
 170         atomic_t finished;
 171         int wait;
 172 } *call_data;
 173
 174 /* delay of at least 8 seconds on 1GHz cpu */
 175 #define SMP_CALL_TIMEOUT (1UL << (30 + 3))
 176
 177 /*
 178  * This function sends a 'generic call function' IPI to all other CPUs
 179  * in the system.
 180  *
 181  * [SUMMARY] Run a function on all other CPUs.
 182  * <func> The function to run. This must be fast and non-blocking.
 183  * <info> An arbitrary pointer to pass to the function.
 184  * <nonatomic> currently unused.
 185  * <wait> If true, wait (atomically) until function has completed on other CPUs.
 186  * [RETURNS] 0 on success, else a negative status code. Does not return until
 187  * remote CPUs are nearly ready to execute <<func>> or are or have executed.
 188  *
 189  * You must not call this function with disabled interrupts or from a
 190  * hardware interrupt handler or from a bottom half handler.
 191  */
 192 int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
 193                        int wait)
 194 {
 195         struct call_data_struct data;
 196         int ret = -1, cpus;
 197         unsigned long timeout;
 198
 199         /* Can deadlock when called with interrupts disabled */
 200         WARN_ON(irqs_disabled());
 201
 202         data.func = func;
 203         data.info = info;
 204         atomic_set(&data.started, 0);
 205         data.wait = wait;
 206         if (wait)
 207                 atomic_set(&data.finished, 0);
 208
 209         spin_lock(&call_lock);
 210         /* Must grab online cpu count with preempt disabled, otherwise
 211          * it can change. */
 212         cpus = num_online_cpus() - 1;
 213         if (!cpus) {
 214                 ret = 0;
 215                 goto out;
 216         }
 217
 218         call_data = &data;
 219         smp_wmb();
 220         /* Send a message to all other CPUs and wait for them to respond */
 221         smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_CALL_FUNCTION);
 222
 223         /* Wait for response */
 224         timeout = SMP_CALL_TIMEOUT;
 225         while (atomic_read(&data.started) != cpus) {
 226                 HMT_low();
 227                 if (--timeout == 0) {
 228                         printk("smp_call_function on cpu %d: other cpus not "
 229                                "responding (%d)\n", smp_processor_id(),
 230                                atomic_read(&data.started));
 231                         debugger(NULL);
 232                         goto out;
 233                 }
 234         }
 235
 236         if (wait) {
 237                 timeout = SMP_CALL_TIMEOUT;
 238                 while (atomic_read(&data.finished) != cpus) {
 239                         HMT_low();
 240                         if (--timeout == 0) {
 241                                 printk("smp_call_function on cpu %d: other "
 242                                        "cpus not finishing (%d/%d)\n",
 243                                        smp_processor_id(),
 244                                        atomic_read(&data.finished),
 245                                        atomic_read(&data.started));
 246                                 debugger(NULL);
 247                                 goto out;
 248                         }
 249                 }
 250         }
 251
 252         ret = 0;
 253
 254 out:
 255         call_data = NULL;
 256         HMT_medium();
 257         spin_unlock(&call_lock);
 258         return ret;
 259 }
 260
 261 EXPORT_SYMBOL(smp_call_function);
 262
 263 void smp_call_function_interrupt(void)
 264 {
 265         void (*func) (void *info);
 266         void *info;
 267         int wait;
 268
 269         /* call_data will be NULL if the sender timed out while
 270          * waiting on us to receive the call.
 271          */
 272         if (!call_data)
 273                 return;
 274
 275         func = call_data->func;
 276         info = call_data->info;
 277         wait = call_data->wait;
 278
 279         if (!wait)
 280                 smp_mb__before_atomic_inc();
 281
 282         /*
 283          * Notify initiating CPU that I've grabbed the data and am
 284          * about to execute the function
 285          */
 286         atomic_inc(&call_data->started);
 287         /*
 288          * At this point the info structure may be out of scope unless wait==1
 289          */
 290         (*func)(info);
 291         if (wait) {
 292                 smp_mb__before_atomic_inc();
 293                 atomic_inc(&call_data->finished);
 294         }
 295 }
 296
 297 extern struct gettimeofday_struct do_gtod;
 298
 299 struct thread_info *current_set[NR_CPUS];
 300
 301 DECLARE_PER_CPU(unsigned int, pvr);
 302
 303 static void __devinit smp_store_cpu_info(int id)
 304 {
 305         per_cpu(pvr, id) = mfspr(SPRN_PVR);
 306 }
 307
 308 static void __init smp_create_idle(unsigned int cpu)
 309 {
 310         struct task_struct *p;
 311
 312         /* create a process for the processor */
 313         p = fork_idle(cpu);
 314         if (IS_ERR(p))
 315                 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
 316         paca[cpu].__current = p;
 317         current_set[cpu] = p->thread_info;
 318 }
 319
 320 void __init smp_prepare_cpus(unsigned int max_cpus)
 321 {
 322         unsigned int cpu;
 323
 324         DBG("smp_prepare_cpus\n");
 325
 326         /*
 327          * setup_cpu may need to be called on the boot cpu. We havent
 328          * spun any cpus up but lets be paranoid.
 329          */
 330         BUG_ON(boot_cpuid != smp_processor_id());
 331
 332         /* Fixup boot cpu */
 333         smp_store_cpu_info(boot_cpuid);
 334         cpu_callin_map[boot_cpuid] = 1;
 335
 336 #ifndef CONFIG_PPC_ISERIES
 337         paca[boot_cpuid].next_jiffy_update_tb = tb_last_stamp = get_tb();
 338
 339         /*
 340          * Should update do_gtod.stamp_xsec.
 341          * For now we leave it which means the time can be some
 342          * number of msecs off until someone does a settimeofday()
 343          */
 344         do_gtod.varp->tb_orig_stamp = tb_last_stamp;
 345         systemcfg->tb_orig_stamp = tb_last_stamp;
 346 #endif
 347
 348         max_cpus = smp_ops->probe();
 349
 350         smp_space_timers(max_cpus);
 351
 352         for_each_cpu(cpu)
 353                 if (cpu != boot_cpuid)
 354                         smp_create_idle(cpu);
 355 }
 356
 357 void __devinit smp_prepare_boot_cpu(void)
 358 {
 359         BUG_ON(smp_processor_id() != boot_cpuid);
 360
 361         cpu_set(boot_cpuid, cpu_online_map);
 362
 363         paca[boot_cpuid].__current = current;
 364         current_set[boot_cpuid] = current->thread_info;
 365 }
 366
 367 #ifdef CONFIG_HOTPLUG_CPU
 368 /* State of each CPU during hotplug phases */
 369 DEFINE_PER_CPU(int, cpu_state) = { 0 };
 370
 371 int generic_cpu_disable(void)
 372 {
 373         unsigned int cpu = smp_processor_id();
 374
 375         if (cpu == boot_cpuid)
 376                 return -EBUSY;
 377
 378         systemcfg->processorCount--;
 379         cpu_clear(cpu, cpu_online_map);
 380         fixup_irqs(cpu_online_map);
 381         return 0;
 382 }
 383
 384 int generic_cpu_enable(unsigned int cpu)
 385 {
 386         /* Do the normal bootup if we haven't
 387          * already bootstrapped. */
 388         if (system_state != SYSTEM_RUNNING)
 389                 return -ENOSYS;
 390
 391         /* get the target out of it's holding state */
 392         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 393         smp_wmb();
 394
 395         while (!cpu_online(cpu))
 396                 cpu_relax();
 397
 398         fixup_irqs(cpu_online_map);
 399         /* counter the irq disable in fixup_irqs */
 400         local_irq_enable();
 401         return 0;
 402 }
 403
 404 void generic_cpu_die(unsigned int cpu)
 405 {
 406         int i;
 407
 408         for (i = 0; i < 100; i++) {
 409                 smp_rmb();
 410                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 411                         return;
 412                 msleep(100);
 413         }
 414         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 415 }
 416
 417 void generic_mach_cpu_die(void)
 418 {
 419         unsigned int cpu;
 420
 421         local_irq_disable();
 422         cpu = smp_processor_id();
 423         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 424         __get_cpu_var(cpu_state) = CPU_DEAD;
 425         smp_wmb();
 426         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 427                 cpu_relax();
 428
 429         flush_tlb_pending();
 430         cpu_set(cpu, cpu_online_map);
 431         local_irq_enable();
 432 }
 433 #endif
 434
 435 static int __devinit cpu_enable(unsigned int cpu)
 436 {
 437         if (smp_ops->cpu_enable)
 438                 return smp_ops->cpu_enable(cpu);
 439
 440         return -ENOSYS;
 441 }
 442
 443 int __devinit __cpu_up(unsigned int cpu)
 444 {
 445         int c;
 446
 447         if (!cpu_enable(cpu))
 448                 return 0;
 449
 450         if (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu))
 451                 return -EINVAL;
 452
 453         paca[cpu].default_decr = tb_ticks_per_jiffy;
 454
 455         /* Make sure callin-map entry is 0 (can be leftover a CPU
 456          * hotplug
 457          */
 458         cpu_callin_map[cpu] = 0;
 459
 460         /* The information for processor bringup must
 461          * be written out to main store before we release
 462          * the processor.
 463          */
 464         smp_mb();
 465
 466         /* wake up cpus */
 467         DBG("smp: kicking cpu %d\n", cpu);
 468         smp_ops->kick_cpu(cpu);
 469
 470         /*
 471          * wait to see if the cpu made a callin (is actually up).
 472          * use this value that I found through experimentation.
 473          * -- Cort
 474          */
 475         if (system_state < SYSTEM_RUNNING)
 476                 for (c = 5000; c && !cpu_callin_map[cpu]; c--)
 477                         udelay(100);
 478 #ifdef CONFIG_HOTPLUG_CPU
 479         else
 480                 /*
 481                  * CPUs can take much longer to come up in the
 482                  * hotplug case.  Wait five seconds.
 483                  */
 484                 for (c = 25; c && !cpu_callin_map[cpu]; c--) {
 485                         msleep(200);
 486                 }
 487 #endif
 488
 489         if (!cpu_callin_map[cpu]) {
 490                 printk("Processor %u is stuck.\n", cpu);
 491                 return -ENOENT;
 492         }
 493
 494         printk("Processor %u found.\n", cpu);
 495
 496         if (smp_ops->give_timebase)
 497                 smp_ops->give_timebase();
 498
 499         /* Wait until cpu puts itself in the online map */
 500         while (!cpu_online(cpu))
 501                 cpu_relax();
 502
 503         return 0;
 504 }
 505
 506
 507 /* Activate a secondary processor. */
 508 int __devinit start_secondary(void *unused)
 509 {
 510         unsigned int cpu = smp_processor_id();
 511
 512         atomic_inc(&init_mm.mm_count);
 513         current->active_mm = &init_mm;
 514
 515         smp_store_cpu_info(cpu);
 516         set_dec(paca[cpu].default_decr);
 517         cpu_callin_map[cpu] = 1;
 518
 519         smp_ops->setup_cpu(cpu);
 520         if (smp_ops->take_timebase)
 521                 smp_ops->take_timebase();
 522
 523         spin_lock(&call_lock);
 524         cpu_set(cpu, cpu_online_map);
 525         spin_unlock(&call_lock);
 526
 527         local_irq_enable();
 528
 529         cpu_idle();
 530         return 0;
 531 }
 532
 533 int setup_profiling_timer(unsigned int multiplier)
 534 {
 535         return 0;
 536 }
 537
 538 void __init smp_cpus_done(unsigned int max_cpus)
 539 {
 540         cpumask_t old_mask;
 541
 542         /* We want the setup_cpu() here to be called from CPU 0, but our
 543          * init thread may have been "borrowed" by another CPU in the meantime
 544          * se we pin us down to CPU 0 for a short while
 545          */
 546         old_mask = current->cpus_allowed;
 547         set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
 548
 549         smp_ops->setup_cpu(boot_cpuid);
 550
 551         set_cpus_allowed(current, old_mask);
 552 }
 553
 554 #ifdef CONFIG_HOTPLUG_CPU
 555 int __cpu_disable(void)
 556 {
 557         if (smp_ops->cpu_disable)
 558                 return smp_ops->cpu_disable();
 559
 560         return -ENOSYS;
 561 }
 562
 563 void __cpu_die(unsigned int cpu)
 564 {
 565         if (smp_ops->cpu_die)
 566                 smp_ops->cpu_die(cpu);
 567 }
 568 #endif