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/cputable.h>
  45 #include <asm/system.h>
  46 #include <asm/mpic.h>
  47 #include <asm/vdso_datapage.h>
  48 #ifdef CONFIG_PPC64
  49 #include <asm/paca.h>
  50 #endif
  51
  52 #ifdef DEBUG
  53 #include <asm/udbg.h>
  54 #define DBG(fmt...) udbg_printf(fmt)
  55 #else
  56 #define DBG(fmt...)
  57 #endif
  58
  59 int smp_hw_index[NR_CPUS];
  60 struct thread_info *secondary_ti;
  61
  62 cpumask_t cpu_possible_map = CPU_MASK_NONE;
  63 cpumask_t cpu_online_map = CPU_MASK_NONE;
  64 DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE;
  65
  66 EXPORT_SYMBOL(cpu_online_map);
  67 EXPORT_SYMBOL(cpu_possible_map);
  68 EXPORT_PER_CPU_SYMBOL(cpu_sibling_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 int smt_enabled_at_boot = 1;
  76
  77 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
  78
  79 #ifdef CONFIG_PPC64
  80 void __devinit smp_generic_kick_cpu(int nr)
  81 {
  82         BUG_ON(nr < 0 || nr >= NR_CPUS);
  83
  84         /*
  85          * The processor is currently spinning, waiting for the
  86          * cpu_start field to become non-zero After we set cpu_start,
  87          * the processor will continue on to secondary_start
  88          */
  89         paca[nr].cpu_start = 1;
  90         smp_mb();
  91 }
  92 #endif
  93
  94 void smp_message_recv(int msg)
  95 {
  96         switch(msg) {
  97         case PPC_MSG_CALL_FUNCTION:
  98                 generic_smp_call_function_interrupt();
  99                 break;
 100         case PPC_MSG_RESCHEDULE:
 101                 /* XXX Do we have to do this? */
 102                 set_need_resched();
 103                 break;
 104         case PPC_MSG_CALL_FUNC_SINGLE:
 105                 generic_smp_call_function_single_interrupt();
 106                 break;
 107         case PPC_MSG_DEBUGGER_BREAK:
 108                 if (crash_ipi_function_ptr) {
 109                         crash_ipi_function_ptr(get_irq_regs());
 110                         break;
 111                 }
 112 #ifdef CONFIG_DEBUGGER
 113                 debugger_ipi(get_irq_regs());
 114                 break;
 115 #endif /* CONFIG_DEBUGGER */
 116                 /* FALLTHROUGH */
 117         default:
 118                 printk("SMP %d: smp_message_recv(): unknown msg %d\n",
 119                        smp_processor_id(), msg);
 120                 break;
 121         }
 122 }
 123
 124 void smp_send_reschedule(int cpu)
 125 {
 126         if (likely(smp_ops))
 127                 smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
 128 }
 129
 130 void arch_send_call_function_single_ipi(int cpu)
 131 {
 132         smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
 133 }
 134
 135 void arch_send_call_function_ipi(cpumask_t mask)
 136 {
 137         unsigned int cpu;
 138
 139         for_each_cpu_mask(cpu, mask)
 140                 smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);
 141 }
 142
 143 #ifdef CONFIG_DEBUGGER
 144 void smp_send_debugger_break(int cpu)
 145 {
 146         if (likely(smp_ops))
 147                 smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
 148 }
 149 #endif
 150
 151 #ifdef CONFIG_KEXEC
 152 void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
 153 {
 154         crash_ipi_function_ptr = crash_ipi_callback;
 155         if (crash_ipi_callback && smp_ops) {
 156                 mb();
 157                 smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
 158         }
 159 }
 160 #endif
 161
 162 static void stop_this_cpu(void *dummy)
 163 {
 164         local_irq_disable();
 165         while (1)
 166                 ;
 167 }
 168
 169 void smp_send_stop(void)
 170 {
 171         smp_call_function(stop_this_cpu, NULL, 0);
 172 }
 173
 174 struct thread_info *current_set[NR_CPUS];
 175
 176 static void __devinit smp_store_cpu_info(int id)
 177 {
 178         per_cpu(pvr, id) = mfspr(SPRN_PVR);
 179 }
 180
 181 static void __init smp_create_idle(unsigned int cpu)
 182 {
 183         struct task_struct *p;
 184
 185         /* create a process for the processor */
 186         p = fork_idle(cpu);
 187         if (IS_ERR(p))
 188                 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
 189 #ifdef CONFIG_PPC64
 190         paca[cpu].__current = p;
 191         paca[cpu].kstack = (unsigned long) task_thread_info(p)
 192                 + THREAD_SIZE - STACK_FRAME_OVERHEAD;
 193 #endif
 194         current_set[cpu] = task_thread_info(p);
 195         task_thread_info(p)->cpu = cpu;
 196 }
 197
 198 void __init smp_prepare_cpus(unsigned int max_cpus)
 199 {
 200         unsigned int cpu;
 201
 202         DBG("smp_prepare_cpus\n");
 203
 204         /*
 205          * setup_cpu may need to be called on the boot cpu. We havent
 206          * spun any cpus up but lets be paranoid.
 207          */
 208         BUG_ON(boot_cpuid != smp_processor_id());
 209
 210         /* Fixup boot cpu */
 211         smp_store_cpu_info(boot_cpuid);
 212         cpu_callin_map[boot_cpuid] = 1;
 213
 214         if (smp_ops)
 215                 max_cpus = smp_ops->probe();
 216         else
 217                 max_cpus = 1;
 218
 219         smp_space_timers(max_cpus);
 220
 221         for_each_possible_cpu(cpu)
 222                 if (cpu != boot_cpuid)
 223                         smp_create_idle(cpu);
 224 }
 225
 226 void __devinit smp_prepare_boot_cpu(void)
 227 {
 228         BUG_ON(smp_processor_id() != boot_cpuid);
 229
 230         cpu_set(boot_cpuid, cpu_online_map);
 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
 379 /* Activate a secondary processor. */
 380 int __devinit start_secondary(void *unused)
 381 {
 382         unsigned int cpu = smp_processor_id();
 383
 384         atomic_inc(&init_mm.mm_count);
 385         current->active_mm = &init_mm;
 386
 387         smp_store_cpu_info(cpu);
 388         set_dec(tb_ticks_per_jiffy);
 389         preempt_disable();
 390         cpu_callin_map[cpu] = 1;
 391
 392         smp_ops->setup_cpu(cpu);
 393         if (smp_ops->take_timebase)
 394                 smp_ops->take_timebase();
 395
 396         if (system_state > SYSTEM_BOOTING)
 397                 snapshot_timebase();
 398
 399         secondary_cpu_time_init();
 400
 401         ipi_call_lock();
 402         cpu_set(cpu, cpu_online_map);
 403         ipi_call_unlock();
 404
 405         local_irq_enable();
 406
 407         cpu_idle();
 408         return 0;
 409 }
 410
 411 int setup_profiling_timer(unsigned int multiplier)
 412 {
 413         return 0;
 414 }
 415
 416 void __init smp_cpus_done(unsigned int max_cpus)
 417 {
 418         cpumask_t old_mask;
 419
 420         /* We want the setup_cpu() here to be called from CPU 0, but our
 421          * init thread may have been "borrowed" by another CPU in the meantime
 422          * se we pin us down to CPU 0 for a short while
 423          */
 424         old_mask = current->cpus_allowed;
 425         set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
 426
 427         if (smp_ops)
 428                 smp_ops->setup_cpu(boot_cpuid);
 429
 430         set_cpus_allowed(current, old_mask);
 431
 432         snapshot_timebases();
 433
 434         dump_numa_cpu_topology();
 435 }
 436
 437 #ifdef CONFIG_HOTPLUG_CPU
 438 int __cpu_disable(void)
 439 {
 440         if (smp_ops->cpu_disable)
 441                 return smp_ops->cpu_disable();
 442
 443         return -ENOSYS;
 444 }
 445
 446 void __cpu_die(unsigned int cpu)
 447 {
 448         if (smp_ops->cpu_die)
 449                 smp_ops->cpu_die(cpu);
 450 }
 451 #endif