Logo Search packages:      
Sourcecode: linux version File versions  Download package

smp.c

/*
 * SMP support for ppc.
 *
 * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great
 * deal of code from the sparc and intel versions.
 *
 * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
 *
 * PowerPC-64 Support added by Dave Engebretsen, Peter Bergner, and
 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#undef DEBUG

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/cache.h>
#include <linux/err.h>
#include <linux/sysdev.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/topology.h>

#include <asm/ptrace.h>
#include <asm/atomic.h>
#include <asm/irq.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include <asm/cputhreads.h>
#include <asm/cputable.h>
#include <asm/system.h>
#include <asm/mpic.h>
#include <asm/vdso_datapage.h>
#ifdef CONFIG_PPC64
#include <asm/paca.h>
#endif

#ifdef DEBUG
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif

int smp_hw_index[NR_CPUS];
struct thread_info *secondary_ti;

cpumask_t cpu_possible_map = CPU_MASK_NONE;
cpumask_t cpu_online_map = CPU_MASK_NONE;
DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE;
DEFINE_PER_CPU(cpumask_t, cpu_core_map) = CPU_MASK_NONE;

EXPORT_SYMBOL(cpu_online_map);
EXPORT_SYMBOL(cpu_possible_map);
EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
EXPORT_PER_CPU_SYMBOL(cpu_core_map);

/* SMP operations for this machine */
struct smp_ops_t *smp_ops;

static volatile unsigned int cpu_callin_map[NR_CPUS];

int smt_enabled_at_boot = 1;

static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;

#ifdef CONFIG_PPC64
void __devinit smp_generic_kick_cpu(int nr)
{
      BUG_ON(nr < 0 || nr >= NR_CPUS);

      /*
       * The processor is currently spinning, waiting for the
       * cpu_start field to become non-zero After we set cpu_start,
       * the processor will continue on to secondary_start
       */
      paca[nr].cpu_start = 1;
      smp_mb();
}
#endif

void smp_message_recv(int msg)
{
      switch(msg) {
      case PPC_MSG_CALL_FUNCTION:
            generic_smp_call_function_interrupt();
            break;
      case PPC_MSG_RESCHEDULE:
            /* we notice need_resched on exit */
            break;
      case PPC_MSG_CALL_FUNC_SINGLE:
            generic_smp_call_function_single_interrupt();
            break;
      case PPC_MSG_DEBUGGER_BREAK:
            if (crash_ipi_function_ptr) {
                  crash_ipi_function_ptr(get_irq_regs());
                  break;
            }
#ifdef CONFIG_DEBUGGER
            debugger_ipi(get_irq_regs());
            break;
#endif /* CONFIG_DEBUGGER */
            /* FALLTHROUGH */
      default:
            printk("SMP %d: smp_message_recv(): unknown msg %d\n",
                   smp_processor_id(), msg);
            break;
      }
}

void smp_send_reschedule(int cpu)
{
      if (likely(smp_ops))
            smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE);
}

void arch_send_call_function_single_ipi(int cpu)
{
      smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE);
}

void arch_send_call_function_ipi(cpumask_t mask)
{
      unsigned int cpu;

      for_each_cpu_mask(cpu, mask)
            smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);
}

#ifdef CONFIG_DEBUGGER
void smp_send_debugger_break(int cpu)
{
      if (likely(smp_ops))
            smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK);
}
#endif

#ifdef CONFIG_KEXEC
void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
{
      crash_ipi_function_ptr = crash_ipi_callback;
      if (crash_ipi_callback && smp_ops) {
            mb();
            smp_ops->message_pass(MSG_ALL_BUT_SELF, PPC_MSG_DEBUGGER_BREAK);
      }
}
#endif

static void stop_this_cpu(void *dummy)
{
      local_irq_disable();
      while (1)
            ;
}

void smp_send_stop(void)
{
      smp_call_function(stop_this_cpu, NULL, 0);
}

struct thread_info *current_set[NR_CPUS];

static void __devinit smp_store_cpu_info(int id)
{
      per_cpu(pvr, id) = mfspr(SPRN_PVR);
}

static void __init smp_create_idle(unsigned int cpu)
{
      struct task_struct *p;

      /* create a process for the processor */
      p = fork_idle(cpu);
      if (IS_ERR(p))
            panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
#ifdef CONFIG_PPC64
      paca[cpu].__current = p;
      paca[cpu].kstack = (unsigned long) task_thread_info(p)
            + THREAD_SIZE - STACK_FRAME_OVERHEAD;
#endif
      current_set[cpu] = task_thread_info(p);
      task_thread_info(p)->cpu = cpu;
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
      unsigned int cpu;

      DBG("smp_prepare_cpus\n");

      /* 
       * setup_cpu may need to be called on the boot cpu. We havent
       * spun any cpus up but lets be paranoid.
       */
      BUG_ON(boot_cpuid != smp_processor_id());

      /* Fixup boot cpu */
      smp_store_cpu_info(boot_cpuid);
      cpu_callin_map[boot_cpuid] = 1;

      if (smp_ops)
            max_cpus = smp_ops->probe();
      else
            max_cpus = 1;
 
      smp_space_timers(max_cpus);

      for_each_possible_cpu(cpu)
            if (cpu != boot_cpuid)
                  smp_create_idle(cpu);
}

void __devinit smp_prepare_boot_cpu(void)
{
      BUG_ON(smp_processor_id() != boot_cpuid);

      cpu_set(boot_cpuid, cpu_online_map);
      cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid));
      cpu_set(boot_cpuid, per_cpu(cpu_core_map, boot_cpuid));
#ifdef CONFIG_PPC64
      paca[boot_cpuid].__current = current;
#endif
      current_set[boot_cpuid] = task_thread_info(current);
}

#ifdef CONFIG_HOTPLUG_CPU
/* State of each CPU during hotplug phases */
DEFINE_PER_CPU(int, cpu_state) = { 0 };

int generic_cpu_disable(void)
{
      unsigned int cpu = smp_processor_id();

      if (cpu == boot_cpuid)
            return -EBUSY;

      cpu_clear(cpu, cpu_online_map);
#ifdef CONFIG_PPC64
      vdso_data->processorCount--;
      fixup_irqs(cpu_online_map);
#endif
      return 0;
}

int generic_cpu_enable(unsigned int cpu)
{
      /* Do the normal bootup if we haven't
       * already bootstrapped. */
      if (system_state != SYSTEM_RUNNING)
            return -ENOSYS;

      /* get the target out of it's holding state */
      per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
      smp_wmb();

      while (!cpu_online(cpu))
            cpu_relax();

#ifdef CONFIG_PPC64
      fixup_irqs(cpu_online_map);
      /* counter the irq disable in fixup_irqs */
      local_irq_enable();
#endif
      return 0;
}

void generic_cpu_die(unsigned int cpu)
{
      int i;

      for (i = 0; i < 100; i++) {
            smp_rmb();
            if (per_cpu(cpu_state, cpu) == CPU_DEAD)
                  return;
            msleep(100);
      }
      printk(KERN_ERR "CPU%d didn't die...\n", cpu);
}

void generic_mach_cpu_die(void)
{
      unsigned int cpu;

      local_irq_disable();
      cpu = smp_processor_id();
      printk(KERN_DEBUG "CPU%d offline\n", cpu);
      __get_cpu_var(cpu_state) = CPU_DEAD;
      smp_wmb();
      while (__get_cpu_var(cpu_state) != CPU_UP_PREPARE)
            cpu_relax();
      cpu_set(cpu, cpu_online_map);
      local_irq_enable();
}
#endif

static int __devinit cpu_enable(unsigned int cpu)
{
      if (smp_ops && smp_ops->cpu_enable)
            return smp_ops->cpu_enable(cpu);

      return -ENOSYS;
}

int __cpuinit __cpu_up(unsigned int cpu)
{
      int c;

      secondary_ti = current_set[cpu];
      if (!cpu_enable(cpu))
            return 0;

      if (smp_ops == NULL ||
          (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu)))
            return -EINVAL;

      /* Make sure callin-map entry is 0 (can be leftover a CPU
       * hotplug
       */
      cpu_callin_map[cpu] = 0;

      /* The information for processor bringup must
       * be written out to main store before we release
       * the processor.
       */
      smp_mb();

      /* wake up cpus */
      DBG("smp: kicking cpu %d\n", cpu);
      smp_ops->kick_cpu(cpu);

      /*
       * wait to see if the cpu made a callin (is actually up).
       * use this value that I found through experimentation.
       * -- Cort
       */
      if (system_state < SYSTEM_RUNNING)
            for (c = 50000; c && !cpu_callin_map[cpu]; c--)
                  udelay(100);
#ifdef CONFIG_HOTPLUG_CPU
      else
            /*
             * CPUs can take much longer to come up in the
             * hotplug case.  Wait five seconds.
             */
            for (c = 25; c && !cpu_callin_map[cpu]; c--) {
                  msleep(200);
            }
#endif

      if (!cpu_callin_map[cpu]) {
            printk("Processor %u is stuck.\n", cpu);
            return -ENOENT;
      }

      printk("Processor %u found.\n", cpu);

      if (smp_ops->give_timebase)
            smp_ops->give_timebase();

      /* Wait until cpu puts itself in the online map */
      while (!cpu_online(cpu))
            cpu_relax();

      return 0;
}

/* Return the value of the reg property corresponding to the given
 * logical cpu.
 */
int cpu_to_core_id(int cpu)
{
      struct device_node *np;
      const int *reg;
      int id = -1;

      np = of_get_cpu_node(cpu, NULL);
      if (!np)
            goto out;

      reg = of_get_property(np, "reg", NULL);
      if (!reg)
            goto out;

      id = *reg;
out:
      of_node_put(np);
      return id;
}

/* Must be called when no change can occur to cpu_present_map,
 * i.e. during cpu online or offline.
 */
static struct device_node *cpu_to_l2cache(int cpu)
{
      struct device_node *np;
      const phandle *php;
      phandle ph;

      if (!cpu_present(cpu))
            return NULL;

      np = of_get_cpu_node(cpu, NULL);
      if (np == NULL)
            return NULL;

      php = of_get_property(np, "l2-cache", NULL);
      if (php == NULL)
            return NULL;
      ph = *php;
      of_node_put(np);

      return of_find_node_by_phandle(ph);
}

/* Activate a secondary processor. */
int __devinit start_secondary(void *unused)
{
      unsigned int cpu = smp_processor_id();
      struct device_node *l2_cache;
      int i, base;

      atomic_inc(&init_mm.mm_count);
      current->active_mm = &init_mm;

      smp_store_cpu_info(cpu);
      set_dec(tb_ticks_per_jiffy);
      preempt_disable();
      cpu_callin_map[cpu] = 1;

      smp_ops->setup_cpu(cpu);
      if (smp_ops->take_timebase)
            smp_ops->take_timebase();

      if (system_state > SYSTEM_BOOTING)
            snapshot_timebase();

      secondary_cpu_time_init();

      ipi_call_lock();
      notify_cpu_starting(cpu);
      cpu_set(cpu, cpu_online_map);
      /* Update sibling maps */
      base = cpu_first_thread_in_core(cpu);
      for (i = 0; i < threads_per_core; i++) {
            if (cpu_is_offline(base + i))
                  continue;
            cpu_set(cpu, per_cpu(cpu_sibling_map, base + i));
            cpu_set(base + i, per_cpu(cpu_sibling_map, cpu));

            /* cpu_core_map should be a superset of
             * cpu_sibling_map even if we don't have cache
             * information, so update the former here, too.
             */
            cpu_set(cpu, per_cpu(cpu_core_map, base +i));
            cpu_set(base + i, per_cpu(cpu_core_map, cpu));
      }
      l2_cache = cpu_to_l2cache(cpu);
      for_each_online_cpu(i) {
            struct device_node *np = cpu_to_l2cache(i);
            if (!np)
                  continue;
            if (np == l2_cache) {
                  cpu_set(cpu, per_cpu(cpu_core_map, i));
                  cpu_set(i, per_cpu(cpu_core_map, cpu));
            }
            of_node_put(np);
      }
      of_node_put(l2_cache);
      ipi_call_unlock();

      local_irq_enable();

      cpu_idle();
      return 0;
}

int setup_profiling_timer(unsigned int multiplier)
{
      return 0;
}

void __init smp_cpus_done(unsigned int max_cpus)
{
      cpumask_t old_mask;

      /* We want the setup_cpu() here to be called from CPU 0, but our
       * init thread may have been "borrowed" by another CPU in the meantime
       * se we pin us down to CPU 0 for a short while
       */
      old_mask = current->cpus_allowed;
      set_cpus_allowed(current, cpumask_of_cpu(boot_cpuid));
      
      if (smp_ops)
            smp_ops->setup_cpu(boot_cpuid);

      set_cpus_allowed(current, old_mask);

      snapshot_timebases();

      dump_numa_cpu_topology();
}

#ifdef CONFIG_HOTPLUG_CPU
int __cpu_disable(void)
{
      struct device_node *l2_cache;
      int cpu = smp_processor_id();
      int base, i;
      int err;

      if (!smp_ops->cpu_disable)
            return -ENOSYS;

      err = smp_ops->cpu_disable();
      if (err)
            return err;

      /* Update sibling maps */
      base = cpu_first_thread_in_core(cpu);
      for (i = 0; i < threads_per_core; i++) {
            cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i));
            cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu));
            cpu_clear(cpu, per_cpu(cpu_core_map, base +i));
            cpu_clear(base + i, per_cpu(cpu_core_map, cpu));
      }

      l2_cache = cpu_to_l2cache(cpu);
      for_each_present_cpu(i) {
            struct device_node *np = cpu_to_l2cache(i);
            if (!np)
                  continue;
            if (np == l2_cache) {
                  cpu_clear(cpu, per_cpu(cpu_core_map, i));
                  cpu_clear(i, per_cpu(cpu_core_map, cpu));
            }
            of_node_put(np);
      }
      of_node_put(l2_cache);


      return 0;
}

void __cpu_die(unsigned int cpu)
{
      if (smp_ops->cpu_die)
            smp_ops->cpu_die(cpu);
}
#endif

Generated by  Doxygen 1.6.0   Back to index