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/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 #include <linux/topology.h>
  35
  36 #include <asm/ptrace.h>
  37 #include <asm/atomic.h>
  38 #include <asm/irq.h>
  39 #include <asm/page.h>
  40 #include <asm/pgtable.h>
  41 #include <asm/prom.h>
  42 #include <asm/smp.h>
  43 #include <asm/time.h>
  44 #include <asm/machdep.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 int smp_hw_index[NR_CPUS];
  61 struct thread_info *secondary_ti;
  62
  63 cpumask_t cpu_possible_map = CPU_MASK_NONE;
  64 cpumask_t cpu_online_map = CPU_MASK_NONE;
  65 cpumask_t cpu_sibling_map[NR_CPUS] = { [0 ... NR_CPUS-1] = CPU_MASK_NONE };
  66
  67 EXPORT_SYMBOL(cpu_online_map);
  68 EXPORT_SYMBOL(cpu_possible_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_MPIC
  82 int __init smp_mpic_probe(void)
  83 {
  84         int nr_cpus;
  85
  86         DBG("smp_mpic_probe()...\n");
  87
  88         nr_cpus = cpus_weight(cpu_possible_map);
  89
  90         DBG("nr_cpus: %d\n", nr_cpus);
  91
  92         if (nr_cpus > 1)
  93                 mpic_request_ipis();
  94
  95         return nr_cpus;
  96 }
  97
  98 void __devinit smp_mpic_setup_cpu(int cpu)
  99 {
 100         mpic_setup_this_cpu();
 101 }
 102 #endif /* CONFIG_MPIC */
 103
 104 #ifdef CONFIG_PPC64
 105 void __devinit smp_generic_kick_cpu(int nr)
 106 {
 107         BUG_ON(nr < 0 || nr >= NR_CPUS);
 108
 109         /*
 110          * The processor is currently spinning, waiting for the
 111          * cpu_start field to become non-zero After we set cpu_start,
 112          * the processor will continue on to secondary_start
 113          */
 114         paca[nr].cpu_start = 1;
 115         smp_mb();
 116 }
 117 #endif
 118
 119 void smp_message_recv(int msg, struct pt_regs *regs)
 120 {
 121         switch(msg) {
 122         case PPC_MSG_CALL_FUNCTION:
 123                 smp_call_function_interrupt();
 124                 break;
 125         case PPC_MSG_RESCHEDULE:
 126                 /* XXX Do we have to do this? */
 127                 set_need_resched();
 128                 break;
 129         case PPC_MSG_DEBUGGER_BREAK:
 130                 if (crash_ipi_function_ptr) {
 131                         crash_ipi_function_ptr(regs);
 132                         break;
 133                 }
 134 #ifdef CONFIG_DEBUGGER
 135                 debugger_ipi(regs);
 136                 break;
 137 #endif /* CONFIG_DEBUGGER */
 138                 /* FALLTHROUGH */
 139         default:
 140                 printk("SMP %d: smp_message_recv(): unknown msg %d\n",
 141                        smp_processor_id(), msg);
 142                 break;
 143         }
 144 }
 145
 146 void smp_send_reschedule(int cpu)
 147 {
 148         smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
 149 }
 150
 151 #ifdef CONFIG_DEBUGGER
 152 void smp_send_debugger_break(int cpu)
 153 {
 154         smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 155 }
 156 #endif
 157
 158 #ifdef CONFIG_KEXEC
 159 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 160 {
 161         crash_ipi_function_ptr = crash_ipi_callback;
 162         if (crash_ipi_callback) {
 163                 mb();
 164                 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
 165         }
 166 }
 167 #endif
 168
 169 static void stop_this_cpu(void *dummy)
 170 {
 171         local_irq_disable();
 172         while (1)
 173                 ;
 174 }
 175
 176 void smp_send_stop(void)
 177 {
 178         smp_call_function(stop_this_cpu, NULL, 1, 0);
 179 }
 180
 181 /*
 182  * Structure and data for smp_call_function(). This is designed to minimise
 183  * static memory requirements. It also looks cleaner.
 184  * Stolen from the i386 version.
 185  */
 186 static  __cacheline_aligned_in_smp DEFINE_SPINLOCK(call_lock);
 187
 188 static struct call_data_struct {
 189         void (*func) (void *info);
 190         void *info;
 191         atomic_t started;
 192         atomic_t finished;
 193         int wait;
 194 } *call_data;
 195
 196 /* delay of at least 8 seconds */
 197 #define SMP_CALL_TIMEOUT        8
 198
 199 /*
 200  * This function sends a 'generic call function' IPI to all other CPUs
 201  * in the system.
 202  *
 203  * [SUMMARY] Run a function on all other CPUs.
 204  * <func> The function to run. This must be fast and non-blocking.
 205  * <info> An arbitrary pointer to pass to the function.
 206  * <nonatomic> currently unused.
 207  * <wait> If true, wait (atomically) until function has completed on other CPUs.
 208  * [RETURNS] 0 on success, else a negative status code. Does not return until
 209  * remote CPUs are nearly ready to execute <<func>> or are or have executed.
 210  *
 211  * You must not call this function with disabled interrupts or from a
 212  * hardware interrupt handler or from a bottom half handler.
 213  */
 214 int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
 215                        int wait)
 216 {
 217         struct call_data_struct data;
 218         int ret = -1, cpus;
 219         u64 timeout;
 220
 221         /* Can deadlock when called with interrupts disabled */
 222         WARN_ON(irqs_disabled());
 223
 224         data.func = func;
 225         data.info = info;
 226         atomic_set(&data.started, 0);
 227         data.wait = wait;
 228         if (wait)
 229                 atomic_set(&data.finished, 0);
 230
 231         spin_lock(&call_lock);
 232         /* Must grab online cpu count with preempt disabled, otherwise
 233          * it can change. */
 234         cpus = num_online_cpus() - 1;
 235         if (!cpus) {
 236                 ret = 0;
 237                 goto out;
 238         }
 239
 240         call_data = &data;
 241         smp_wmb();
 242         /* Send a message to all other CPUs and wait for them to respond */
 243         smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_CALL_FUNCTION);
 244
 245         timeout = get_tb() + (u64) SMP_CALL_TIMEOUT * tb_ticks_per_sec;
 246
 247         /* Wait for response */
 248         while (atomic_read(&data.started) != cpus) {
 249                 HMT_low();
 250                 if (get_tb() >= timeout) {
 251                         printk("smp_call_function on cpu %d: other cpus not "
 252                                "responding (%d)\n", smp_processor_id(),
 253                                atomic_read(&data.started));
 254                         debugger(NULL);
 255                         goto out;
 256                 }
 257         }
 258
 259         if (wait) {
 260                 while (atomic_read(&data.finished) != cpus) {
 261                         HMT_low();
 262                         if (get_tb() >= timeout) {
 263                                 printk("smp_call_function on cpu %d: other "
 264                                        "cpus not finishing (%d/%d)\n",
 265                                        smp_processor_id(),
 266                                        atomic_read(&data.finished),
 267                                        atomic_read(&data.started));
 268                                 debugger(NULL);
 269                                 goto out;
 270                         }
 271                 }
 272         }
 273
 274         ret = 0;
 275
 276  out:
 277         call_data = NULL;
 278         HMT_medium();
 279         spin_unlock(&call_lock);
 280         return ret;
 281 }
 282
 283 EXPORT_SYMBOL(smp_call_function);
 284
 285 void smp_call_function_interrupt(void)
 286 {
 287         void (*func) (void *info);
 288         void *info;
 289         int wait;
 290
 291         /* call_data will be NULL if the sender timed out while
 292          * waiting on us to receive the call.
 293          */
 294         if (!call_data)
 295                 return;
 296
 297         func = call_data->func;
 298         info = call_data->info;
 299         wait = call_data->wait;
 300
 301         if (!wait)
 302                 smp_mb__before_atomic_inc();
 303
 304         /*
 305          * Notify initiating CPU that I've grabbed the data and am
 306          * about to execute the function
 307          */
 308         atomic_inc(&call_data->started);
 309         /*
 310          * At this point the info structure may be out of scope unless wait==1
 311          */
 312         (*func)(info);
 313         if (wait) {
 314                 smp_mb__before_atomic_inc();
 315                 atomic_inc(&call_data->finished);
 316         }
 317 }
 318
 319 extern struct gettimeofday_struct do_gtod;
 320
 321 struct thread_info *current_set[NR_CPUS];
 322
 323 DECLARE_PER_CPU(unsigned int, pvr);
 324
 325 static void __devinit smp_store_cpu_info(int id)
 326 {
 327         per_cpu(pvr, id) = mfspr(SPRN_PVR);
 328 }
 329
 330 static void __init smp_create_idle(unsigned int cpu)
 331 {
 332         struct task_struct *p;
 333
 334         /* create a process for the processor */
 335         p = fork_idle(cpu);
 336         if (IS_ERR(p))
 337                 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
 338 #ifdef CONFIG_PPC64
 339         paca[cpu].__current = p;
 340 #endif
 341         current_set[cpu] = p->thread_info;
 342         p->thread_info->cpu = cpu;
 343 }
 344
 345 void __init smp_prepare_cpus(unsigned int max_cpus)
 346 {
 347         unsigned int cpu;
 348
 349         DBG("smp_prepare_cpus\n");
 350
 351         /*
 352          * setup_cpu may need to be called on the boot cpu. We havent
 353          * spun any cpus up but lets be paranoid.
 354          */
 355         BUG_ON(boot_cpuid != smp_processor_id());
 356
 357         /* Fixup boot cpu */
 358         smp_store_cpu_info(boot_cpuid);
 359         cpu_callin_map[boot_cpuid] = 1;
 360
 361         max_cpus = smp_ops->probe();
 362
 363         smp_space_timers(max_cpus);
 364
 365         for_each_cpu(cpu)
 366                 if (cpu != boot_cpuid)
 367                         smp_create_idle(cpu);
 368 }
 369
 370 void __devinit smp_prepare_boot_cpu(void)
 371 {
 372         BUG_ON(smp_processor_id() != boot_cpuid);
 373
 374         cpu_set(boot_cpuid, cpu_online_map);
 375 #ifdef CONFIG_PPC64
 376         paca[boot_cpuid].__current = current;
 377 #endif
 378         current_set[boot_cpuid] = current->thread_info;
 379 }
 380
 381 #ifdef CONFIG_HOTPLUG_CPU
 382 /* State of each CPU during hotplug phases */
 383 DEFINE_PER_CPU(int, cpu_state) = { 0 };
 384
 385 int generic_cpu_disable(void)
 386 {
 387         unsigned int cpu = smp_processor_id();
 388
 389         if (cpu == boot_cpuid)
 390                 return -EBUSY;
 391
 392         cpu_clear(cpu, cpu_online_map);
 393 #ifdef CONFIG_PPC64
 394         vdso_data->processorCount--;
 395         fixup_irqs(cpu_online_map);
 396 #endif
 397         return 0;
 398 }
 399
 400 int generic_cpu_enable(unsigned int cpu)
 401 {
 402         /* Do the normal bootup if we haven't
 403          * already bootstrapped. */
 404         if (system_state != SYSTEM_RUNNING)
 405                 return -ENOSYS;
 406
 407         /* get the target out of it's holding state */
 408         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 409         smp_wmb();
 410
 411         while (!cpu_online(cpu))
 412                 cpu_relax();
 413
 414 #ifdef CONFIG_PPC64
 415         fixup_irqs(cpu_online_map);
 416         /* counter the irq disable in fixup_irqs */
 417         local_irq_enable();
 418 #endif
 419         return 0;
 420 }
 421
 422 void generic_cpu_die(unsigned int cpu)
 423 {
 424         int i;
 425
 426         for (i = 0; i < 100; i++) {
 427                 smp_rmb();
 428                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 429                         return;
 430                 msleep(100);
 431         }
 432         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 433 }
 434
 435 void generic_mach_cpu_die(void)
 436 {
 437         unsigned int cpu;
 438
 439         local_irq_disable();
 440         cpu = smp_processor_id();
 441         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 442         __get_cpu_var(cpu_state) = CPU_DEAD;
 443         smp_wmb();
 444         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 445                 cpu_relax();
 446
 447 #ifdef CONFIG_PPC64
 448         flush_tlb_pending();
 449 #endif
 450         cpu_set(cpu, cpu_online_map);
 451         local_irq_enable();
 452 }
 453 #endif
 454
 455 static int __devinit cpu_enable(unsigned int cpu)
 456 {
 457         if (smp_ops->cpu_enable)
 458                 return smp_ops->cpu_enable(cpu);
 459
 460         return -ENOSYS;
 461 }
 462
 463 int __devinit __cpu_up(unsigned int cpu)
 464 {
 465         int c;
 466
 467         secondary_ti = current_set[cpu];
 468         if (!cpu_enable(cpu))
 469                 return 0;
 470
 471         if (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu))
 472                 return -EINVAL;
 473
 474         /* Make sure callin-map entry is 0 (can be leftover a CPU
 475          * hotplug
 476          */
 477         cpu_callin_map[cpu] = 0;
 478
 479         /* The information for processor bringup must
 480          * be written out to main store before we release
 481          * the processor.
 482          */
 483         smp_mb();
 484
 485         /* wake up cpus */
 486         DBG("smp: kicking cpu %d\n", cpu);
 487         smp_ops->kick_cpu(cpu);
 488
 489         /*
 490          * wait to see if the cpu made a callin (is actually up).
 491          * use this value that I found through experimentation.
 492          * -- Cort
 493          */
 494         if (system_state < SYSTEM_RUNNING)
 495                 for (c = 5000; c && !cpu_callin_map[cpu]; c--)
 496                         udelay(100);
 497 #ifdef CONFIG_HOTPLUG_CPU
 498         else
 499                 /*
 500                  * CPUs can take much longer to come up in the
 501                  * hotplug case.  Wait five seconds.
 502                  */
 503                 for (c = 25; c && !cpu_callin_map[cpu]; c--) {
 504                         msleep(200);
 505                 }
 506 #endif
 507
 508         if (!cpu_callin_map[cpu]) {
 509                 printk("Processor %u is stuck.\n", cpu);
 510                 return -ENOENT;
 511         }
 512
 513         printk("Processor %u found.\n", cpu);
 514
 515         if (smp_ops->give_timebase)
 516                 smp_ops->give_timebase();
 517
 518         /* Wait until cpu puts itself in the online map */
 519         while (!cpu_online(cpu))
 520                 cpu_relax();
 521
 522         return 0;
 523 }
 524
 525
 526 /* Activate a secondary processor. */
 527 int __devinit start_secondary(void *unused)
 528 {
 529         unsigned int cpu = smp_processor_id();
 530
 531         atomic_inc(&init_mm.mm_count);
 532         current->active_mm = &init_mm;
 533
 534         smp_store_cpu_info(cpu);
 535         set_dec(tb_ticks_per_jiffy);
 536         preempt_disable();
 537         cpu_callin_map[cpu] = 1;
 538
 539         smp_ops->setup_cpu(cpu);
 540         if (smp_ops->take_timebase)
 541                 smp_ops->take_timebase();
 542
 543         spin_lock(&call_lock);
 544         cpu_set(cpu, cpu_online_map);
 545         spin_unlock(&call_lock);
 546
 547         local_irq_enable();
 548
 549         cpu_idle();
 550         return 0;
 551 }
 552
 553 int setup_profiling_timer(unsigned int multiplier)
 554 {
 555         return 0;
 556 }
 557
 558 void __init smp_cpus_done(unsigned int max_cpus)
 559 {
 560         cpumask_t old_mask;
 561
 562         /* We want the setup_cpu() here to be called from CPU 0, but our
 563          * init thread may have been "borrowed" by another CPU in the meantime
 564          * se we pin us down to CPU 0 for a short while
 565          */
 566         old_mask = current->cpus_allowed;
 567         set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
 568
 569         smp_ops->setup_cpu(boot_cpuid);
 570
 571         set_cpus_allowed(current, old_mask);
 572
 573         dump_numa_cpu_topology();
 574 }
 575
 576 #ifdef CONFIG_HOTPLUG_CPU
 577 int __cpu_disable(void)
 578 {
 579         if (smp_ops->cpu_disable)
 580                 return smp_ops->cpu_disable();
 581
 582         return -ENOSYS;
 583 }
 584
 585 void __cpu_die(unsigned int cpu)
 586 {
 587         if (smp_ops->cpu_die)
 588                 smp_ops->cpu_die(cpu);
 589 }
 590 #endif