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smp.c

/*
 * arch/sh/kernel/smp.c
 *
 * SMP support for the SuperH processors.
 *
 * Copyright (C) 2002 - 2007 Paul Mundt
 * Copyright (C) 2006 - 2007 Akio Idehara
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/err.h>
#include <linux/cache.h>
#include <linux/cpumask.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <asm/atomic.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/mmu_context.h>
#include <asm/smp.h>
#include <asm/cacheflush.h>
#include <asm/sections.h>

int __cpu_number_map[NR_CPUS];            /* Map physical to logical */
int __cpu_logical_map[NR_CPUS];           /* Map logical to physical */

cpumask_t cpu_possible_map;
EXPORT_SYMBOL(cpu_possible_map);

cpumask_t cpu_online_map;
EXPORT_SYMBOL(cpu_online_map);

static inline void __init smp_store_cpu_info(unsigned int cpu)
{
      struct sh_cpuinfo *c = cpu_data + cpu;

      c->loops_per_jiffy = loops_per_jiffy;
}

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

      init_new_context(current, &init_mm);
      current_thread_info()->cpu = cpu;
      plat_prepare_cpus(max_cpus);

#ifndef CONFIG_HOTPLUG_CPU
      cpu_present_map = cpu_possible_map;
#endif
}

void __devinit smp_prepare_boot_cpu(void)
{
      unsigned int cpu = smp_processor_id();

      __cpu_number_map[0] = cpu;
      __cpu_logical_map[0] = cpu;

      cpu_set(cpu, cpu_online_map);
      cpu_set(cpu, cpu_possible_map);
}

asmlinkage void __cpuinit start_secondary(void)
{
      unsigned int cpu;
      struct mm_struct *mm = &init_mm;

      atomic_inc(&mm->mm_count);
      atomic_inc(&mm->mm_users);
      current->active_mm = mm;
      BUG_ON(current->mm);
      enter_lazy_tlb(mm, current);

      per_cpu_trap_init();

      preempt_disable();

      local_irq_enable();

      calibrate_delay();

      cpu = smp_processor_id();
      smp_store_cpu_info(cpu);

      cpu_set(cpu, cpu_online_map);

      cpu_idle();
}

extern struct {
      unsigned long sp;
      unsigned long bss_start;
      unsigned long bss_end;
      void *start_kernel_fn;
      void *cpu_init_fn;
      void *thread_info;
} stack_start;

int __cpuinit __cpu_up(unsigned int cpu)
{
      struct task_struct *tsk;
      unsigned long timeout;

      tsk = fork_idle(cpu);
      if (IS_ERR(tsk)) {
            printk(KERN_ERR "Failed forking idle task for cpu %d\n", cpu);
            return PTR_ERR(tsk);
      }

      /* Fill in data in head.S for secondary cpus */
      stack_start.sp = tsk->thread.sp;
      stack_start.thread_info = tsk->stack;
      stack_start.bss_start = 0; /* don't clear bss for secondary cpus */
      stack_start.start_kernel_fn = start_secondary;

      flush_cache_all();

      plat_start_cpu(cpu, (unsigned long)_stext);

      timeout = jiffies + HZ;
      while (time_before(jiffies, timeout)) {
            if (cpu_online(cpu))
                  break;

            udelay(10);
      }

      if (cpu_online(cpu))
            return 0;

      return -ENOENT;
}

void __init smp_cpus_done(unsigned int max_cpus)
{
      unsigned long bogosum = 0;
      int cpu;

      for_each_online_cpu(cpu)
            bogosum += cpu_data[cpu].loops_per_jiffy;

      printk(KERN_INFO "SMP: Total of %d processors activated "
             "(%lu.%02lu BogoMIPS).\n", num_online_cpus(),
             bogosum / (500000/HZ),
             (bogosum / (5000/HZ)) % 100);
}

void smp_send_reschedule(int cpu)
{
      plat_send_ipi(cpu, SMP_MSG_RESCHEDULE);
}

static void stop_this_cpu(void *unused)
{
      cpu_clear(smp_processor_id(), cpu_online_map);
      local_irq_disable();

      for (;;)
            cpu_relax();
}

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

void arch_send_call_function_ipi(cpumask_t mask)
{
      int cpu;

      for_each_cpu_mask(cpu, mask)
            plat_send_ipi(cpu, SMP_MSG_FUNCTION);
}

void arch_send_call_function_single_ipi(int cpu)
{
      plat_send_ipi(cpu, SMP_MSG_FUNCTION_SINGLE);
}

/* 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, 0, 1);
}

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

/*
 * 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_call_function(flush_tlb_mm_ipi, (void *)mm, 1);
      } else {
            int i;
            for (i = 0; i < num_online_cpus(); i++)
                  if (smp_processor_id() != i)
                        cpu_context(i, 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 = (struct flush_tlb_data *)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;

            fd.vma = vma;
            fd.addr1 = start;
            fd.addr2 = end;
            smp_call_function(flush_tlb_range_ipi, (void *)&fd, 1);
      } else {
            int i;
            for (i = 0; i < num_online_cpus(); i++)
                  if (smp_processor_id() != i)
                        cpu_context(i, 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 = (struct flush_tlb_data *)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;

      fd.addr1 = start;
      fd.addr2 = end;
      on_each_cpu(flush_tlb_kernel_range_ipi, (void *)&fd, 1);
}

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

            fd.vma = vma;
            fd.addr1 = page;
            smp_call_function(flush_tlb_page_ipi, (void *)&fd, 1);
      } else {
            int i;
            for (i = 0; i < num_online_cpus(); i++)
                  if (smp_processor_id() != i)
                        cpu_context(i, vma->vm_mm) = 0;
      }
      local_flush_tlb_page(vma, page);
      preempt_enable();
}

static void flush_tlb_one_ipi(void *info)
{
      struct flush_tlb_data *fd = (struct flush_tlb_data *)info;
      local_flush_tlb_one(fd->addr1, fd->addr2);
}

void flush_tlb_one(unsigned long asid, unsigned long vaddr)
{
      struct flush_tlb_data fd;

      fd.addr1 = asid;
      fd.addr2 = vaddr;

      smp_call_function(flush_tlb_one_ipi, (void *)&fd, 1);
      local_flush_tlb_one(asid, vaddr);
}

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