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 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 DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE;
  66 DEFINE_PER_CPU(cpumask_t, cpu_core_map) = CPU_MASK_NONE;
  67
  68 EXPORT_SYMBOL(cpu_online_map);
  69 EXPORT_SYMBOL(cpu_possible_map);
  70 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
  71 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
  72
  73 /* SMP operations for this machine */
  74 struct smp_ops_t *smp_ops;
  75
  76 static volatile unsigned int cpu_callin_map[NR_CPUS];
  77
  78 int smt_enabled_at_boot = 1;
  79
  80 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
  81
  82 #ifdef CONFIG_PPC64
  83 void __devinit smp_generic_kick_cpu(int nr)
  84 {
  85         BUG_ON(nr < 0 || nr >= NR_CPUS);
  86
  87         /*
  88          * The processor is currently spinning, waiting for the
  89          * cpu_start field to become non-zero After we set cpu_start,
  90          * the processor will continue on to secondary_start
  91          */
  92         paca[nr].cpu_start = 1;
  93         smp_mb();
  94 }
  95 #endif
  96
  97 void smp_message_recv(int msg)
  98 {
  99         switch(msg) {
 100         case PPC_MSG_CALL_FUNCTION:
 101                 generic_smp_call_function_interrupt();
 102                 break;
 103         case PPC_MSG_RESCHEDULE:
 104                 /* we notice need_resched on exit */
 105                 break;
 106         case PPC_MSG_CALL_FUNC_SINGLE:
 107                 generic_smp_call_function_single_interrupt();
 108                 break;
 109         case PPC_MSG_DEBUGGER_BREAK:
 110                 if (crash_ipi_function_ptr) {
 111                         crash_ipi_function_ptr(get_irq_regs());
 112                         break;
 113                 }
 114 #ifdef CONFIG_DEBUGGER
 115                 debugger_ipi(get_irq_regs());
 116                 break;
 117 #endif /* CONFIG_DEBUGGER */
 118                 /* FALLTHROUGH */
 119         default:
 120                 printk("SMP %d: smp_message_recv(): unknown msg %d\n",
 121                        smp_processor_id(), msg);
 122                 break;
 123         }
 124 }
 125
 126 void smp_send_reschedule(int cpu)
 127 {
 128         if (likely(smp_ops))
 129                 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
 130 }
 131
 132 void arch_send_call_function_single_ipi(int cpu)
 133 {
 134         smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
 135 }
 136
 137 void arch_send_call_function_ipi(cpumask_t mask)
 138 {
 139         unsigned int cpu;
 140
 141         for_each_cpu_mask(cpu, mask)
 142                 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);
 143 }
 144
 145 #ifdef CONFIG_DEBUGGER
 146 void smp_send_debugger_break(int cpu)
 147 {
 148         if (likely(smp_ops))
 149                 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 150 }
 151 #endif
 152
 153 #ifdef CONFIG_KEXEC
 154 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 155 {
 156         crash_ipi_function_ptr = crash_ipi_callback;
 157         if (crash_ipi_callback && smp_ops) {
 158                 mb();
 159                 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
 160         }
 161 }
 162 #endif
 163
 164 static void stop_this_cpu(void *dummy)
 165 {
 166         local_irq_disable();
 167         while (1)
 168                 ;
 169 }
 170
 171 void smp_send_stop(void)
 172 {
 173         smp_call_function(stop_this_cpu, NULL, 0);
 174 }
 175
 176 struct thread_info *current_set[NR_CPUS];
 177
 178 static void __devinit smp_store_cpu_info(int id)
 179 {
 180         per_cpu(pvr, id) = mfspr(SPRN_PVR);
 181 }
 182
 183 static void __init smp_create_idle(unsigned int cpu)
 184 {
 185         struct task_struct *p;
 186
 187         /* create a process for the processor */
 188         p = fork_idle(cpu);
 189         if (IS_ERR(p))
 190                 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
 191 #ifdef CONFIG_PPC64
 192         paca[cpu].__current = p;
 193         paca[cpu].kstack = (unsigned long) task_thread_info(p)
 194                 + THREAD_SIZE - STACK_FRAME_OVERHEAD;
 195 #endif
 196         current_set[cpu] = task_thread_info(p);
 197         task_thread_info(p)->cpu = cpu;
 198 }
 199
 200 void __init smp_prepare_cpus(unsigned int max_cpus)
 201 {
 202         unsigned int cpu;
 203
 204         DBG("smp_prepare_cpus\n");
 205
 206         /*
 207          * setup_cpu may need to be called on the boot cpu. We havent
 208          * spun any cpus up but lets be paranoid.
 209          */
 210         BUG_ON(boot_cpuid != smp_processor_id());
 211
 212         /* Fixup boot cpu */
 213         smp_store_cpu_info(boot_cpuid);
 214         cpu_callin_map[boot_cpuid] = 1;
 215
 216         if (smp_ops)
 217                 max_cpus = smp_ops->probe();
 218         else
 219                 max_cpus = 1;
 220
 221         smp_space_timers(max_cpus);
 222
 223         for_each_possible_cpu(cpu)
 224                 if (cpu != boot_cpuid)
 225                         smp_create_idle(cpu);
 226 }
 227
 228 void __devinit smp_prepare_boot_cpu(void)
 229 {
 230         BUG_ON(smp_processor_id() != boot_cpuid);
 231
 232         cpu_set(boot_cpuid, cpu_online_map);
 233         cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid));
 234         cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid));
 235 #ifdef CONFIG_PPC64
 236         paca[boot_cpuid].__current = current;
 237 #endif
 238         current_set[boot_cpuid] = task_thread_info(current);
 239 }
 240
 241 #ifdef CONFIG_HOTPLUG_CPU
 242 /* State of each CPU during hotplug phases */
 243 DEFINE_PER_CPU(int, cpu_state) = { 0 };
 244
 245 int generic_cpu_disable(void)
 246 {
 247         unsigned int cpu = smp_processor_id();
 248
 249         if (cpu == boot_cpuid)
 250                 return -EBUSY;
 251
 252         cpu_clear(cpu, cpu_online_map);
 253 #ifdef CONFIG_PPC64
 254         vdso_data->processorCount--;
 255         fixup_irqs(cpu_online_map);
 256 #endif
 257         return 0;
 258 }
 259
 260 int generic_cpu_enable(unsigned int cpu)
 261 {
 262         /* Do the normal bootup if we haven't
 263          * already bootstrapped. */
 264         if (system_state != SYSTEM_RUNNING)
 265                 return -ENOSYS;
 266
 267         /* get the target out of it's holding state */
 268         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 269         smp_wmb();
 270
 271         while (!cpu_online(cpu))
 272                 cpu_relax();
 273
 274 #ifdef CONFIG_PPC64
 275         fixup_irqs(cpu_online_map);
 276         /* counter the irq disable in fixup_irqs */
 277         local_irq_enable();
 278 #endif
 279         return 0;
 280 }
 281
 282 void generic_cpu_die(unsigned int cpu)
 283 {
 284         int i;
 285
 286         for (i = 0; i < 100; i++) {
 287                 smp_rmb();
 288                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 289                         return;
 290                 msleep(100);
 291         }
 292         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 293 }
 294
 295 void generic_mach_cpu_die(void)
 296 {
 297         unsigned int cpu;
 298
 299         local_irq_disable();
 300         cpu = smp_processor_id();
 301         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 302         __get_cpu_var(cpu_state) = CPU_DEAD;
 303         smp_wmb();
 304         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 305                 cpu_relax();
 306         cpu_set(cpu, cpu_online_map);
 307         local_irq_enable();
 308 }
 309 #endif
 310
 311 static int __devinit cpu_enable(unsigned int cpu)
 312 {
 313         if (smp_ops && smp_ops->cpu_enable)
 314                 return smp_ops->cpu_enable(cpu);
 315
 316         return -ENOSYS;
 317 }
 318
 319 int __cpuinit __cpu_up(unsigned int cpu)
 320 {
 321         int c;
 322
 323         secondary_ti = current_set[cpu];
 324         if (!cpu_enable(cpu))
 325                 return 0;
 326
 327         if (smp_ops == NULL ||
 328             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 329                 return -EINVAL;
 330
 331         /* Make sure callin-map entry is 0 (can be leftover a CPU
 332          * hotplug
 333          */
 334         cpu_callin_map[cpu] = 0;
 335
 336         /* The information for processor bringup must
 337          * be written out to main store before we release
 338          * the processor.
 339          */
 340         smp_mb();
 341
 342         /* wake up cpus */
 343         DBG("smp: kicking cpu %d\n", cpu);
 344         smp_ops->kick_cpu(cpu);
 345
 346         /*
 347          * wait to see if the cpu made a callin (is actually up).
 348          * use this value that I found through experimentation.
 349          * -- Cort
 350          */
 351         if (system_state < SYSTEM_RUNNING)
 352                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
 353                         udelay(100);
 354 #ifdef CONFIG_HOTPLUG_CPU
 355         else
 356                 /*
 357                  * CPUs can take much longer to come up in the
 358                  * hotplug case.  Wait five seconds.
 359                  */
 360                 for (c = 25; c && !cpu_callin_map[cpu]; c--) {
 361                         msleep(200);
 362                 }
 363 #endif
 364
 365         if (!cpu_callin_map[cpu]) {
 366                 printk("Processor %u is stuck.\n", cpu);
 367                 return -ENOENT;
 368         }
 369
 370         printk("Processor %u found.\n", cpu);
 371
 372         if (smp_ops->give_timebase)
 373                 smp_ops->give_timebase();
 374
 375         /* Wait until cpu puts itself in the online map */
 376         while (!cpu_online(cpu))
 377                 cpu_relax();
 378
 379         return 0;
 380 }
 381
 382 /* Return the value of the reg property corresponding to the given
 383  * logical cpu.
 384  */
 385 int cpu_to_core_id(int cpu)
 386 {
 387         struct device_node *np;
 388         const int *reg;
 389         int id = -1;
 390
 391         np = of_get_cpu_node(cpu, NULL);
 392         if (!np)
 393                 goto out;
 394
 395         reg = of_get_property(np, "reg", NULL);
 396         if (!reg)
 397                 goto out;
 398
 399         id = *reg;
 400 out:
 401         of_node_put(np);
 402         return id;
 403 }
 404
 405 /* Must be called when no change can occur to cpu_present_map,
 406  * i.e. during cpu online or offline.
 407  */
 408 static struct device_node *cpu_to_l2cache(int cpu)
 409 {
 410         struct device_node *np;
 411         const phandle *php;
 412         phandle ph;
 413
 414         if (!cpu_present(cpu))
 415                 return NULL;
 416
 417         np = of_get_cpu_node(cpu, NULL);
 418         if (np == NULL)
 419                 return NULL;
 420
 421         php = of_get_property(np, "l2-cache", NULL);
 422         if (php == NULL)
 423                 return NULL;
 424         ph = *php;
 425         of_node_put(np);
 426
 427         return of_find_node_by_phandle(ph);
 428 }
 429
 430 /* Activate a secondary processor. */
 431 int __devinit start_secondary(void *unused)
 432 {
 433         unsigned int cpu = smp_processor_id();
 434         struct device_node *l2_cache;
 435         int i, base;
 436
 437         atomic_inc(&init_mm.mm_count);
 438         current->active_mm = &init_mm;
 439
 440         smp_store_cpu_info(cpu);
 441         set_dec(tb_ticks_per_jiffy);
 442         preempt_disable();
 443         cpu_callin_map[cpu] = 1;
 444
 445         smp_ops->setup_cpu(cpu);
 446         if (smp_ops->take_timebase)
 447                 smp_ops->take_timebase();
 448
 449         if (system_state > SYSTEM_BOOTING)
 450                 snapshot_timebase();
 451
 452         secondary_cpu_time_init();
 453
 454         ipi_call_lock();
 455         notify_cpu_starting(cpu);
 456         cpu_set(cpu, cpu_online_map);
 457         /* Update sibling maps */
 458         base = cpu_first_thread_in_core(cpu);
 459         for (i = 0; i < threads_per_core; i++) {
 460                 if (cpu_is_offline(base + i))
 461                         continue;
 462                 cpu_set(cpu, per_cpu(cpu_sibling_map, base + i));
 463                 cpu_set(base + i, per_cpu(cpu_sibling_map, cpu));
 464
 465                 /* cpu_core_map should be a superset of
 466                  * cpu_sibling_map even if we don't have cache
 467                  * information, so update the former here, too.
 468                  */
 469                 cpu_set(cpu, per_cpu(cpu_core_map, base +i));
 470                 cpu_set(base + i, per_cpu(cpu_core_map, cpu));
 471         }
 472         l2_cache = cpu_to_l2cache(cpu);
 473         for_each_online_cpu(i) {
 474                 struct device_node *np = cpu_to_l2cache(i);
 475                 if (!np)
 476                         continue;
 477                 if (np == l2_cache) {
 478                         cpu_set(cpu, per_cpu(cpu_core_map, i));
 479                         cpu_set(i, per_cpu(cpu_core_map, cpu));
 480                 }
 481                 of_node_put(np);
 482         }
 483         of_node_put(l2_cache);
 484         ipi_call_unlock();
 485
 486         local_irq_enable();
 487
 488         cpu_idle();
 489         return 0;
 490 }
 491
 492 int setup_profiling_timer(unsigned int multiplier)
 493 {
 494         return 0;
 495 }
 496
 497 void __init smp_cpus_done(unsigned int max_cpus)
 498 {
 499         cpumask_t old_mask;
 500
 501         /* We want the setup_cpu() here to be called from CPU 0, but our
 502          * init thread may have been "borrowed" by another CPU in the meantime
 503          * se we pin us down to CPU 0 for a short while
 504          */
 505         old_mask = current->cpus_allowed;
 506         set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
 507
 508         if (smp_ops)
 509                 smp_ops->setup_cpu(boot_cpuid);
 510
 511         set_cpus_allowed(current, old_mask);
 512
 513         snapshot_timebases();
 514
 515         dump_numa_cpu_topology();
 516 }
 517
 518 #ifdef CONFIG_HOTPLUG_CPU
 519 int __cpu_disable(void)
 520 {
 521         struct device_node *l2_cache;
 522         int cpu = smp_processor_id();
 523         int base, i;
 524         int err;
 525
 526         if (!smp_ops->cpu_disable)
 527                 return -ENOSYS;
 528
 529         err = smp_ops->cpu_disable();
 530         if (err)
 531                 return err;
 532
 533         /* Update sibling maps */
 534         base = cpu_first_thread_in_core(cpu);
 535         for (i = 0; i < threads_per_core; i++) {
 536                 cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i));
 537                 cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu));
 538                 cpu_clear(cpu, per_cpu(cpu_core_map, base +i));
 539                 cpu_clear(base + i, per_cpu(cpu_core_map, cpu));
 540         }
 541
 542         l2_cache = cpu_to_l2cache(cpu);
 543         for_each_present_cpu(i) {
 544                 struct device_node *np = cpu_to_l2cache(i);
 545                 if (!np)
 546                         continue;
 547                 if (np == l2_cache) {
 548                         cpu_clear(cpu, per_cpu(cpu_core_map, i));
 549                         cpu_clear(i, per_cpu(cpu_core_map, cpu));
 550                 }
 551                 of_node_put(np);
 552         }
 553         of_node_put(l2_cache);
 554
 555
 556         return 0;
 557 }
 558
 559 void __cpu_die(unsigned int cpu)
 560 {
 561         if (smp_ops->cpu_die)
 562                 smp_ops->cpu_die(cpu);
 563 }
 564 #endif