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   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 DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE;
  64 DEFINE_PER_CPU(cpumask_t, cpu_core_map) = CPU_MASK_NONE;
  65
  66 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
  67 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
  68
  69 /* SMP operations for this machine */
  70 struct smp_ops_t *smp_ops;
  71
  72 static volatile unsigned int cpu_callin_map[NR_CPUS];
  73
  74 int smt_enabled_at_boot = 1;
  75
  76 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
  77
  78 #ifdef CONFIG_PPC64
  79 void __devinit smp_generic_kick_cpu(int nr)
  80 {
  81         BUG_ON(nr < 0 || nr >= NR_CPUS);
  82
  83         /*
  84          * The processor is currently spinning, waiting for the
  85          * cpu_start field to become non-zero After we set cpu_start,
  86          * the processor will continue on to secondary_start
  87          */
  88         paca[nr].cpu_start = 1;
  89         smp_mb();
  90 }
  91 #endif
  92
  93 void smp_message_recv(int msg)
  94 {
  95         switch(msg) {
  96         case PPC_MSG_CALL_FUNCTION:
  97                 generic_smp_call_function_interrupt();
  98                 break;
  99         case PPC_MSG_RESCHEDULE:
 100                 /* we notice need_resched on exit */
 101                 break;
 102         case PPC_MSG_CALL_FUNC_SINGLE:
 103                 generic_smp_call_function_single_interrupt();
 104                 break;
 105         case PPC_MSG_DEBUGGER_BREAK:
 106                 if (crash_ipi_function_ptr) {
 107                         crash_ipi_function_ptr(get_irq_regs());
 108                         break;
 109                 }
 110 #ifdef CONFIG_DEBUGGER
 111                 debugger_ipi(get_irq_regs());
 112                 break;
 113 #endif /* CONFIG_DEBUGGER */
 114                 /* FALLTHROUGH */
 115         default:
 116                 printk("SMP %d: smp_message_recv(): unknown msg %d\n",
 117                        smp_processor_id(), msg);
 118                 break;
 119         }
 120 }
 121
 122 void smp_send_reschedule(int cpu)
 123 {
 124         if (likely(smp_ops))
 125                 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
 126 }
 127
 128 void arch_send_call_function_single_ipi(int cpu)
 129 {
 130         smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
 131 }
 132
 133 void arch_send_call_function_ipi(cpumask_t mask)
 134 {
 135         unsigned int cpu;
 136
 137         for_each_cpu_mask(cpu, mask)
 138                 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);
 139 }
 140
 141 #ifdef CONFIG_DEBUGGER
 142 void smp_send_debugger_break(int cpu)
 143 {
 144         if (likely(smp_ops))
 145                 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 146 }
 147 #endif
 148
 149 #ifdef CONFIG_KEXEC
 150 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 151 {
 152         crash_ipi_function_ptr = crash_ipi_callback;
 153         if (crash_ipi_callback && smp_ops) {
 154                 mb();
 155                 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
 156         }
 157 }
 158 #endif
 159
 160 static void stop_this_cpu(void *dummy)
 161 {
 162         local_irq_disable();
 163         while (1)
 164                 ;
 165 }
 166
 167 void smp_send_stop(void)
 168 {
 169         smp_call_function(stop_this_cpu, NULL, 0);
 170 }
 171
 172 struct thread_info *current_set[NR_CPUS];
 173
 174 static void __devinit smp_store_cpu_info(int id)
 175 {
 176         per_cpu(pvr, id) = mfspr(SPRN_PVR);
 177 }
 178
 179 static void __init smp_create_idle(unsigned int cpu)
 180 {
 181         struct task_struct *p;
 182
 183         /* create a process for the processor */
 184         p = fork_idle(cpu);
 185         if (IS_ERR(p))
 186                 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
 187 #ifdef CONFIG_PPC64
 188         paca[cpu].__current = p;
 189         paca[cpu].kstack = (unsigned long) task_thread_info(p)
 190                 + THREAD_SIZE - STACK_FRAME_OVERHEAD;
 191 #endif
 192         current_set[cpu] = task_thread_info(p);
 193         task_thread_info(p)->cpu = cpu;
 194 }
 195
 196 void __init smp_prepare_cpus(unsigned int max_cpus)
 197 {
 198         unsigned int cpu;
 199
 200         DBG("smp_prepare_cpus\n");
 201
 202         /*
 203          * setup_cpu may need to be called on the boot cpu. We havent
 204          * spun any cpus up but lets be paranoid.
 205          */
 206         BUG_ON(boot_cpuid != smp_processor_id());
 207
 208         /* Fixup boot cpu */
 209         smp_store_cpu_info(boot_cpuid);
 210         cpu_callin_map[boot_cpuid] = 1;
 211
 212         if (smp_ops)
 213                 max_cpus = smp_ops->probe();
 214         else
 215                 max_cpus = 1;
 216
 217         smp_space_timers(max_cpus);
 218
 219         for_each_possible_cpu(cpu)
 220                 if (cpu != boot_cpuid)
 221                         smp_create_idle(cpu);
 222 }
 223
 224 void __devinit smp_prepare_boot_cpu(void)
 225 {
 226         BUG_ON(smp_processor_id() != boot_cpuid);
 227
 228         cpu_set(boot_cpuid, cpu_online_map);
 229         cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid));
 230         cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid));
 231 #ifdef CONFIG_PPC64
 232         paca[boot_cpuid].__current = current;
 233 #endif
 234         current_set[boot_cpuid] = task_thread_info(current);
 235 }
 236
 237 #ifdef CONFIG_HOTPLUG_CPU
 238 /* State of each CPU during hotplug phases */
 239 DEFINE_PER_CPU(int, cpu_state) = { 0 };
 240
 241 int generic_cpu_disable(void)
 242 {
 243         unsigned int cpu = smp_processor_id();
 244
 245         if (cpu == boot_cpuid)
 246                 return -EBUSY;
 247
 248         cpu_clear(cpu, cpu_online_map);
 249 #ifdef CONFIG_PPC64
 250         vdso_data->processorCount--;
 251         fixup_irqs(cpu_online_map);
 252 #endif
 253         return 0;
 254 }
 255
 256 int generic_cpu_enable(unsigned int cpu)
 257 {
 258         /* Do the normal bootup if we haven't
 259          * already bootstrapped. */
 260         if (system_state != SYSTEM_RUNNING)
 261                 return -ENOSYS;
 262
 263         /* get the target out of it's holding state */
 264         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 265         smp_wmb();
 266
 267         while (!cpu_online(cpu))
 268                 cpu_relax();
 269
 270 #ifdef CONFIG_PPC64
 271         fixup_irqs(cpu_online_map);
 272         /* counter the irq disable in fixup_irqs */
 273         local_irq_enable();
 274 #endif
 275         return 0;
 276 }
 277
 278 void generic_cpu_die(unsigned int cpu)
 279 {
 280         int i;
 281
 282         for (i = 0; i < 100; i++) {
 283                 smp_rmb();
 284                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 285                         return;
 286                 msleep(100);
 287         }
 288         printk(KERN_ERR "CPU%d didn't die...\n", cpu);
 289 }
 290
 291 void generic_mach_cpu_die(void)
 292 {
 293         unsigned int cpu;
 294
 295         local_irq_disable();
 296         cpu = smp_processor_id();
 297         printk(KERN_DEBUG "CPU%d offline\n", cpu);
 298         __get_cpu_var(cpu_state) = CPU_DEAD;
 299         smp_wmb();
 300         while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
 301                 cpu_relax();
 302         cpu_set(cpu, cpu_online_map);
 303         local_irq_enable();
 304 }
 305 #endif
 306
 307 static int __devinit cpu_enable(unsigned int cpu)
 308 {
 309         if (smp_ops && smp_ops->cpu_enable)
 310                 return smp_ops->cpu_enable(cpu);
 311
 312         return -ENOSYS;
 313 }
 314
 315 int __cpuinit __cpu_up(unsigned int cpu)
 316 {
 317         int c;
 318
 319         secondary_ti = current_set[cpu];
 320         if (!cpu_enable(cpu))
 321                 return 0;
 322
 323         if (smp_ops == NULL ||
 324             (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
 325                 return -EINVAL;
 326
 327         /* Make sure callin-map entry is 0 (can be leftover a CPU
 328          * hotplug
 329          */
 330         cpu_callin_map[cpu] = 0;
 331
 332         /* The information for processor bringup must
 333          * be written out to main store before we release
 334          * the processor.
 335          */
 336         smp_mb();
 337
 338         /* wake up cpus */
 339         DBG("smp: kicking cpu %d\n", cpu);
 340         smp_ops->kick_cpu(cpu);
 341
 342         /*
 343          * wait to see if the cpu made a callin (is actually up).
 344          * use this value that I found through experimentation.
 345          * -- Cort
 346          */
 347         if (system_state < SYSTEM_RUNNING)
 348                 for (c = 50000; c && !cpu_callin_map[cpu]; c--)
 349                         udelay(100);
 350 #ifdef CONFIG_HOTPLUG_CPU
 351         else
 352                 /*
 353                  * CPUs can take much longer to come up in the
 354                  * hotplug case.  Wait five seconds.
 355                  */
 356                 for (c = 25; c && !cpu_callin_map[cpu]; c--) {
 357                         msleep(200);
 358                 }
 359 #endif
 360
 361         if (!cpu_callin_map[cpu]) {
 362                 printk("Processor %u is stuck.\n", cpu);
 363                 return -ENOENT;
 364         }
 365
 366         printk("Processor %u found.\n", cpu);
 367
 368         if (smp_ops->give_timebase)
 369                 smp_ops->give_timebase();
 370
 371         /* Wait until cpu puts itself in the online map */
 372         while (!cpu_online(cpu))
 373                 cpu_relax();
 374
 375         return 0;
 376 }
 377
 378 /* Return the value of the reg property corresponding to the given
 379  * logical cpu.
 380  */
 381 int cpu_to_core_id(int cpu)
 382 {
 383         struct device_node *np;
 384         const int *reg;
 385         int id = -1;
 386
 387         np = of_get_cpu_node(cpu, NULL);
 388         if (!np)
 389                 goto out;
 390
 391         reg = of_get_property(np, "reg", NULL);
 392         if (!reg)
 393                 goto out;
 394
 395         id = *reg;
 396 out:
 397         of_node_put(np);
 398         return id;
 399 }
 400
 401 /* Must be called when no change can occur to cpu_present_map,
 402  * i.e. during cpu online or offline.
 403  */
 404 static struct device_node *cpu_to_l2cache(int cpu)
 405 {
 406         struct device_node *np;
 407         const phandle *php;
 408         phandle ph;
 409
 410         if (!cpu_present(cpu))
 411                 return NULL;
 412
 413         np = of_get_cpu_node(cpu, NULL);
 414         if (np == NULL)
 415                 return NULL;
 416
 417         php = of_get_property(np, "l2-cache", NULL);
 418         if (php == NULL)
 419                 return NULL;
 420         ph = *php;
 421         of_node_put(np);
 422
 423         return of_find_node_by_phandle(ph);
 424 }
 425
 426 /* Activate a secondary processor. */
 427 int __devinit start_secondary(void *unused)
 428 {
 429         unsigned int cpu = smp_processor_id();
 430         struct device_node *l2_cache;
 431         int i, base;
 432
 433         atomic_inc(&init_mm.mm_count);
 434         current->active_mm = &init_mm;
 435
 436         smp_store_cpu_info(cpu);
 437         set_dec(tb_ticks_per_jiffy);
 438         preempt_disable();
 439         cpu_callin_map[cpu] = 1;
 440
 441         smp_ops->setup_cpu(cpu);
 442         if (smp_ops->take_timebase)
 443                 smp_ops->take_timebase();
 444
 445         if (system_state > SYSTEM_BOOTING)
 446                 snapshot_timebase();
 447
 448         secondary_cpu_time_init();
 449
 450         ipi_call_lock();
 451         notify_cpu_starting(cpu);
 452         cpu_set(cpu, cpu_online_map);
 453         /* Update sibling maps */
 454         base = cpu_first_thread_in_core(cpu);
 455         for (i = 0; i < threads_per_core; i++) {
 456                 if (cpu_is_offline(base + i))
 457                         continue;
 458                 cpu_set(cpu, per_cpu(cpu_sibling_map, base + i));
 459                 cpu_set(base + i, per_cpu(cpu_sibling_map, cpu));
 460
 461                 /* cpu_core_map should be a superset of
 462                  * cpu_sibling_map even if we don't have cache
 463                  * information, so update the former here, too.
 464                  */
 465                 cpu_set(cpu, per_cpu(cpu_core_map, base +i));
 466                 cpu_set(base + i, per_cpu(cpu_core_map, cpu));
 467         }
 468         l2_cache = cpu_to_l2cache(cpu);
 469         for_each_online_cpu(i) {
 470                 struct device_node *np = cpu_to_l2cache(i);
 471                 if (!np)
 472                         continue;
 473                 if (np == l2_cache) {
 474                         cpu_set(cpu, per_cpu(cpu_core_map, i));
 475                         cpu_set(i, per_cpu(cpu_core_map, cpu));
 476                 }
 477                 of_node_put(np);
 478         }
 479         of_node_put(l2_cache);
 480         ipi_call_unlock();
 481
 482         local_irq_enable();
 483
 484         cpu_idle();
 485         return 0;
 486 }
 487
 488 int setup_profiling_timer(unsigned int multiplier)
 489 {
 490         return 0;
 491 }
 492
 493 void __init smp_cpus_done(unsigned int max_cpus)
 494 {
 495         cpumask_t old_mask;
 496
 497         /* We want the setup_cpu() here to be called from CPU 0, but our
 498          * init thread may have been "borrowed" by another CPU in the meantime
 499          * se we pin us down to CPU 0 for a short while
 500          */
 501         old_mask = current->cpus_allowed;
 502         set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
 503
 504         if (smp_ops)
 505                 smp_ops->setup_cpu(boot_cpuid);
 506
 507         set_cpus_allowed(current, old_mask);
 508
 509         snapshot_timebases();
 510
 511         dump_numa_cpu_topology();
 512 }
 513
 514 #ifdef CONFIG_HOTPLUG_CPU
 515 int __cpu_disable(void)
 516 {
 517         struct device_node *l2_cache;
 518         int cpu = smp_processor_id();
 519         int base, i;
 520         int err;
 521
 522         if (!smp_ops->cpu_disable)
 523                 return -ENOSYS;
 524
 525         err = smp_ops->cpu_disable();
 526         if (err)
 527                 return err;
 528
 529         /* Update sibling maps */
 530         base = cpu_first_thread_in_core(cpu);
 531         for (i = 0; i < threads_per_core; i++) {
 532                 cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i));
 533                 cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu));
 534                 cpu_clear(cpu, per_cpu(cpu_core_map, base +i));
 535                 cpu_clear(base + i, per_cpu(cpu_core_map, cpu));
 536         }
 537
 538         l2_cache = cpu_to_l2cache(cpu);
 539         for_each_present_cpu(i) {
 540                 struct device_node *np = cpu_to_l2cache(i);
 541                 if (!np)
 542                         continue;
 543                 if (np == l2_cache) {
 544                         cpu_clear(cpu, per_cpu(cpu_core_map, i));
 545                         cpu_clear(i, per_cpu(cpu_core_map, cpu));
 546                 }
 547                 of_node_put(np);
 548         }
 549         of_node_put(l2_cache);
 550
 551
 552         return 0;
 553 }
 554
 555 void __cpu_die(unsigned int cpu)
 556 {
 557         if (smp_ops->cpu_die)
 558                 smp_ops->cpu_die(cpu);
 559 }
 560 #endif