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