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/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;

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

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

static volatile unsigned int cpu_callin_map[NR_CPUS];

void smp_call_function_interrupt(void);

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:
            smp_call_function_interrupt();
            break;
      case PPC_MSG_RESCHEDULE:
            /* XXX Do we have to do this? */
            set_need_resched();
            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);
}

#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)
            ;
}

/*
 * Structure and data for smp_call_function(). This is designed to minimise
 * static memory requirements. It also looks cleaner.
 * Stolen from the i386 version.
 */
static  __cacheline_aligned_in_smp DEFINE_SPINLOCK(call_lock);

static struct call_data_struct {
      void (*func) (void *info);
      void *info;
      atomic_t started;
      atomic_t finished;
      int wait;
} *call_data;

/* delay of at least 8 seconds */
#define SMP_CALL_TIMEOUT      8

/*
 * These functions send a 'generic call function' IPI to other online
 * CPUS in the system.
 *
 * [SUMMARY] Run a function on other CPUs.
 * <func> The function to run. This must be fast and non-blocking.
 * <info> An arbitrary pointer to pass to the function.
 * <nonatomic> currently unused.
 * <wait> If true, wait (atomically) until function has completed on other CPUs.
 * [RETURNS] 0 on success, else a negative status code. Does not return until
 * remote CPUs are nearly ready to execute <<func>> or are or have executed.
 *
 * You must not call this function with disabled interrupts or from a
 * hardware interrupt handler or from a bottom half handler.
 */
int smp_call_function_map(void (*func) (void *info), void *info, int nonatomic,
                  int wait, cpumask_t map)
{
      struct call_data_struct data;
      int ret = -1, num_cpus;
      int cpu;
      u64 timeout;

      if (unlikely(smp_ops == NULL))
            return ret;

      data.func = func;
      data.info = info;
      atomic_set(&data.started, 0);
      data.wait = wait;
      if (wait)
            atomic_set(&data.finished, 0);

      spin_lock(&call_lock);

      /* remove 'self' from the map */
      if (cpu_isset(smp_processor_id(), map))
            cpu_clear(smp_processor_id(), map);

      /* sanity check the map, remove any non-online processors. */
      cpus_and(map, map, cpu_online_map);

      num_cpus = cpus_weight(map);
      if (!num_cpus)
            goto done;

      call_data = &data;
      smp_wmb();
      /* Send a message to all CPUs in the map */
      for_each_cpu_mask(cpu, map)
            smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION);

      timeout = get_tb() + (u64) SMP_CALL_TIMEOUT * tb_ticks_per_sec;

      /* Wait for indication that they have received the message */
      while (atomic_read(&data.started) != num_cpus) {
            HMT_low();
            if (get_tb() >= timeout) {
                  printk("smp_call_function on cpu %d: other cpus not "
                        "responding (%d)\n", smp_processor_id(),
                        atomic_read(&data.started));
                  debugger(NULL);
                  goto out;
            }
      }

      /* optionally wait for the CPUs to complete */
      if (wait) {
            while (atomic_read(&data.finished) != num_cpus) {
                  HMT_low();
                  if (get_tb() >= timeout) {
                        printk("smp_call_function on cpu %d: other "
                              "cpus not finishing (%d/%d)\n",
                              smp_processor_id(),
                              atomic_read(&data.finished),
                              atomic_read(&data.started));
                        debugger(NULL);
                        goto out;
                  }
            }
      }

 done:
      ret = 0;

 out:
      call_data = NULL;
      HMT_medium();
      spin_unlock(&call_lock);
      return ret;
}

static int __smp_call_function(void (*func)(void *info), void *info,
                         int nonatomic, int wait)
{
      return smp_call_function_map(func,info,nonatomic,wait,cpu_online_map);
}

int smp_call_function(void (*func) (void *info), void *info, int nonatomic,
                  int wait)
{
      /* Can deadlock when called with interrupts disabled */
      WARN_ON(irqs_disabled());

      return __smp_call_function(func, info, nonatomic, wait);
}
EXPORT_SYMBOL(smp_call_function);

int smp_call_function_single(int cpu, void (*func) (void *info), void *info, int nonatomic,
                  int wait)
{
      cpumask_t map = CPU_MASK_NONE;
      int ret = 0;

      /* Can deadlock when called with interrupts disabled */
      WARN_ON(irqs_disabled());

      if (!cpu_online(cpu))
            return -EINVAL;

      cpu_set(cpu, map);
      if (cpu != get_cpu())
            ret = smp_call_function_map(func,info,nonatomic,wait,map);
      else {
            local_irq_disable();
            func(info);
            local_irq_enable();
      }
      put_cpu();
      return ret;
}
EXPORT_SYMBOL(smp_call_function_single);

void smp_send_stop(void)
{
      __smp_call_function(stop_this_cpu, NULL, 1, 0);
}

void smp_call_function_interrupt(void)
{
      void (*func) (void *info);
      void *info;
      int wait;

      /* call_data will be NULL if the sender timed out while
       * waiting on us to receive the call.
       */
      if (!call_data)
            return;

      func = call_data->func;
      info = call_data->info;
      wait = call_data->wait;

      if (!wait)
            smp_mb__before_atomic_inc();

      /*
       * Notify initiating CPU that I've grabbed the data and am
       * about to execute the function
       */
      atomic_inc(&call_data->started);
      /*
       * At this point the info structure may be out of scope unless wait==1
       */
      (*func)(info);
      if (wait) {
            smp_mb__before_atomic_inc();
            atomic_inc(&call_data->finished);
      }
}

extern struct gettimeofday_struct do_gtod;

struct thread_info *current_set[NR_CPUS];

DECLARE_PER_CPU(unsigned int, pvr);

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;
#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);
#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;
}


/* Activate a secondary processor. */
int __devinit start_secondary(void *unused)
{
      unsigned int cpu = smp_processor_id();

      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();

      spin_lock(&call_lock);
      cpu_set(cpu, cpu_online_map);
      spin_unlock(&call_lock);

      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)
{
      if (smp_ops->cpu_disable)
            return smp_ops->cpu_disable();

      return -ENOSYS;
}

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