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smp.c

/*
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * Copyright (C) 2000, 2001 Kanoj Sarcar
 * Copyright (C) 2000, 2001 Ralf Baechle
 * Copyright (C) 2000, 2001 Silicon Graphics, Inc.
 * Copyright (C) 2000, 2001, 2003 Broadcom Corporation
 */
#include <linux/cache.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/threads.h>
#include <linux/module.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/sched.h>
#include <linux/cpumask.h>
#include <linux/cpu.h>
#include <linux/err.h>

#include <asm/atomic.h>
#include <asm/cpu.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/mmu_context.h>
#include <asm/smp.h>
#include <asm/time.h>

#ifdef CONFIG_MIPS_MT_SMTC
#include <asm/mipsmtregs.h>
#endif /* CONFIG_MIPS_MT_SMTC */

cpumask_t phys_cpu_present_map;           /* Bitmask of available CPUs */
volatile cpumask_t cpu_callin_map;  /* Bitmask of started secondaries */
cpumask_t cpu_online_map;           /* Bitmask of currently online CPUs */
int __cpu_number_map[NR_CPUS];            /* Map physical to logical */
int __cpu_logical_map[NR_CPUS];           /* Map logical to physical */

EXPORT_SYMBOL(phys_cpu_present_map);
EXPORT_SYMBOL(cpu_online_map);

extern void __init calibrate_delay(void);
extern void cpu_idle(void);

/*
 * First C code run on the secondary CPUs after being started up by
 * the master.
 */
asmlinkage __cpuinit void start_secondary(void)
{
      unsigned int cpu;

#ifdef CONFIG_MIPS_MT_SMTC
      /* Only do cpu_probe for first TC of CPU */
      if ((read_c0_tcbind() & TCBIND_CURTC) == 0)
#endif /* CONFIG_MIPS_MT_SMTC */
      cpu_probe();
      cpu_report();
      per_cpu_trap_init();
      mips_clockevent_init();
      prom_init_secondary();

      /*
       * XXX parity protection should be folded in here when it's converted
       * to an option instead of something based on .cputype
       */

      calibrate_delay();
      preempt_disable();
      cpu = smp_processor_id();
      cpu_data[cpu].udelay_val = loops_per_jiffy;

      prom_smp_finish();

      cpu_set(cpu, cpu_callin_map);

      cpu_idle();
}

DEFINE_SPINLOCK(smp_call_lock);

struct call_data_struct *call_data;

/*
 * Run a function on all other CPUs.
 *
 *  <mask>  cpuset_t of all processors to run the function on.
 *  <func>      The function to run. This must be fast and non-blocking.
 *  <info>      An arbitrary pointer to pass to the function.
 *  <retry>     If true, keep retrying until ready.
 *  <wait>      If true, wait 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:
 *
 * CPU A                               CPU B
 * Disable interrupts
 *                                     smp_call_function()
 *                                     Take call_lock
 *                                     Send IPIs
 *                                     Wait for all cpus to acknowledge IPI
 *                                     CPU A has not responded, spin waiting
 *                                     for cpu A to respond, holding call_lock
 * smp_call_function()
 * Spin waiting for call_lock
 * Deadlock                            Deadlock
 */
int smp_call_function_mask(cpumask_t mask, void (*func) (void *info),
      void *info, int retry, int wait)
{
      struct call_data_struct data;
      int cpu = smp_processor_id();
      int cpus;

      /*
       * Can die spectacularly if this CPU isn't yet marked online
       */
      BUG_ON(!cpu_online(cpu));

      cpu_clear(cpu, mask);
      cpus = cpus_weight(mask);
      if (!cpus)
            return 0;

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

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

      spin_lock(&smp_call_lock);
      call_data = &data;
      smp_mb();

      /* Send a message to all other CPUs and wait for them to respond */
      core_send_ipi_mask(mask, SMP_CALL_FUNCTION);

      /* Wait for response */
      /* FIXME: lock-up detection, backtrace on lock-up */
      while (atomic_read(&data.started) != cpus)
            barrier();

      if (wait)
            while (atomic_read(&data.finished) != cpus)
                  barrier();
      call_data = NULL;
      spin_unlock(&smp_call_lock);

      return 0;
}

int smp_call_function(void (*func) (void *info), void *info, int retry,
      int wait)
{
      return smp_call_function_mask(cpu_online_map, func, info, retry, wait);
}

void smp_call_function_interrupt(void)
{
      void (*func) (void *info) = call_data->func;
      void *info = call_data->info;
      int wait = call_data->wait;

      /*
       * Notify initiating CPU that I've grabbed the data and am
       * about to execute the function.
       */
      smp_mb();
      atomic_inc(&call_data->started);

      /*
       * At this point the info structure may be out of scope unless wait==1.
       */
      irq_enter();
      (*func)(info);
      irq_exit();

      if (wait) {
            smp_mb();
            atomic_inc(&call_data->finished);
      }
}

int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
                       int retry, int wait)
{
      int ret, me;

      /*
       * Can die spectacularly if this CPU isn't yet marked online
       */
      if (!cpu_online(cpu))
            return 0;

      me = get_cpu();
      BUG_ON(!cpu_online(me));

      if (cpu == me) {
            local_irq_disable();
            func(info);
            local_irq_enable();
            put_cpu();
            return 0;
      }

      ret = smp_call_function_mask(cpumask_of_cpu(cpu), func, info, retry,
                             wait);

      put_cpu();
      return 0;
}

static void stop_this_cpu(void *dummy)
{
      /*
       * Remove this CPU:
       */
      cpu_clear(smp_processor_id(), cpu_online_map);
      local_irq_enable();     /* May need to service _machine_restart IPI */
      for (;;);         /* Wait if available. */
}

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

void __init smp_cpus_done(unsigned int max_cpus)
{
      prom_cpus_done();
}

/* called from main before smp_init() */
void __init smp_prepare_cpus(unsigned int max_cpus)
{
      init_new_context(current, &init_mm);
      current_thread_info()->cpu = 0;
      plat_prepare_cpus(max_cpus);
#ifndef CONFIG_HOTPLUG_CPU
      cpu_present_map = cpu_possible_map;
#endif
}

/* preload SMP state for boot cpu */
void __devinit smp_prepare_boot_cpu(void)
{
      /*
       * This assumes that bootup is always handled by the processor
       * with the logic and physical number 0.
       */
      __cpu_number_map[0] = 0;
      __cpu_logical_map[0] = 0;
      cpu_set(0, phys_cpu_present_map);
      cpu_set(0, cpu_online_map);
      cpu_set(0, cpu_callin_map);
}

/*
 * Called once for each "cpu_possible(cpu)".  Needs to spin up the cpu
 * and keep control until "cpu_online(cpu)" is set.  Note: cpu is
 * physical, not logical.
 */
int __cpuinit __cpu_up(unsigned int cpu)
{
      struct task_struct *idle;

      /*
       * Processor goes to start_secondary(), sets online flag
       * The following code is purely to make sure
       * Linux can schedule processes on this slave.
       */
      idle = fork_idle(cpu);
      if (IS_ERR(idle))
            panic(KERN_ERR "Fork failed for CPU %d", cpu);

      prom_boot_secondary(cpu, idle);

      /*
       * Trust is futile.  We should really have timeouts ...
       */
      while (!cpu_isset(cpu, cpu_callin_map))
            udelay(100);

      cpu_set(cpu, cpu_online_map);

      return 0;
}

/* Not really SMP stuff ... */
int setup_profiling_timer(unsigned int multiplier)
{
      return 0;
}

static void flush_tlb_all_ipi(void *info)
{
      local_flush_tlb_all();
}

void flush_tlb_all(void)
{
      on_each_cpu(flush_tlb_all_ipi, NULL, 1, 1);
}

static void flush_tlb_mm_ipi(void *mm)
{
      local_flush_tlb_mm((struct mm_struct *)mm);
}

/*
 * Special Variant of smp_call_function for use by TLB functions:
 *
 *  o No return value
 *  o collapses to normal function call on UP kernels
 *  o collapses to normal function call on systems with a single shared
 *    primary cache.
 *  o CONFIG_MIPS_MT_SMTC currently implies there is only one physical core.
 */
static inline void smp_on_other_tlbs(void (*func) (void *info), void *info)
{
#ifndef CONFIG_MIPS_MT_SMTC
      smp_call_function(func, info, 1, 1);
#endif
}

static inline void smp_on_each_tlb(void (*func) (void *info), void *info)
{
      preempt_disable();

      smp_on_other_tlbs(func, info);
      func(info);

      preempt_enable();
}

/*
 * The following tlb flush calls are invoked when old translations are
 * being torn down, or pte attributes are changing. For single threaded
 * address spaces, a new context is obtained on the current cpu, and tlb
 * context on other cpus are invalidated to force a new context allocation
 * at switch_mm time, should the mm ever be used on other cpus. For
 * multithreaded address spaces, intercpu interrupts have to be sent.
 * Another case where intercpu interrupts are required is when the target
 * mm might be active on another cpu (eg debuggers doing the flushes on
 * behalf of debugees, kswapd stealing pages from another process etc).
 * Kanoj 07/00.
 */

void flush_tlb_mm(struct mm_struct *mm)
{
      preempt_disable();

      if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
            smp_on_other_tlbs(flush_tlb_mm_ipi, mm);
      } else {
            cpumask_t mask = cpu_online_map;
            unsigned int cpu;

            cpu_clear(smp_processor_id(), mask);
            for_each_cpu_mask(cpu, mask)
                  if (cpu_context(cpu, mm))
                        cpu_context(cpu, mm) = 0;
      }
      local_flush_tlb_mm(mm);

      preempt_enable();
}

struct flush_tlb_data {
      struct vm_area_struct *vma;
      unsigned long addr1;
      unsigned long addr2;
};

static void flush_tlb_range_ipi(void *info)
{
      struct flush_tlb_data *fd = info;

      local_flush_tlb_range(fd->vma, fd->addr1, fd->addr2);
}

void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
      struct mm_struct *mm = vma->vm_mm;

      preempt_disable();
      if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
            struct flush_tlb_data fd = {
                  .vma = vma,
                  .addr1 = start,
                  .addr2 = end,
            };

            smp_on_other_tlbs(flush_tlb_range_ipi, &fd);
      } else {
            cpumask_t mask = cpu_online_map;
            unsigned int cpu;

            cpu_clear(smp_processor_id(), mask);
            for_each_cpu_mask(cpu, mask)
                  if (cpu_context(cpu, mm))
                        cpu_context(cpu, mm) = 0;
      }
      local_flush_tlb_range(vma, start, end);
      preempt_enable();
}

static void flush_tlb_kernel_range_ipi(void *info)
{
      struct flush_tlb_data *fd = info;

      local_flush_tlb_kernel_range(fd->addr1, fd->addr2);
}

void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
      struct flush_tlb_data fd = {
            .addr1 = start,
            .addr2 = end,
      };

      on_each_cpu(flush_tlb_kernel_range_ipi, &fd, 1, 1);
}

static void flush_tlb_page_ipi(void *info)
{
      struct flush_tlb_data *fd = info;

      local_flush_tlb_page(fd->vma, fd->addr1);
}

void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
      preempt_disable();
      if ((atomic_read(&vma->vm_mm->mm_users) != 1) || (current->mm != vma->vm_mm)) {
            struct flush_tlb_data fd = {
                  .vma = vma,
                  .addr1 = page,
            };

            smp_on_other_tlbs(flush_tlb_page_ipi, &fd);
      } else {
            cpumask_t mask = cpu_online_map;
            unsigned int cpu;

            cpu_clear(smp_processor_id(), mask);
            for_each_cpu_mask(cpu, mask)
                  if (cpu_context(cpu, vma->vm_mm))
                        cpu_context(cpu, vma->vm_mm) = 0;
      }
      local_flush_tlb_page(vma, page);
      preempt_enable();
}

static void flush_tlb_one_ipi(void *info)
{
      unsigned long vaddr = (unsigned long) info;

      local_flush_tlb_one(vaddr);
}

void flush_tlb_one(unsigned long vaddr)
{
      smp_on_each_tlb(flush_tlb_one_ipi, (void *) vaddr);
}

EXPORT_SYMBOL(flush_tlb_page);
EXPORT_SYMBOL(flush_tlb_one);

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