smp.c

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/*
 * arch/sh/kernel/smp.c
 *
 * SMP support for the SuperH processors.
 *
 * Copyright (C) 2002 - 2010 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/cpu.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/atomic.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>
#include <asm/smp.h>
#include <asm/cacheflush.h>
#include <asm/sections.h>
#include <asm/setup.h>

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

struct plat_smp_ops *mp_ops = NULL;

/* State of each CPU */
DEFINE_PER_CPU(int, cpu_state) = { 0 };

void __cpuinit register_smp_ops(struct plat_smp_ops *ops)
{
    if (mp_ops)
        printk(KERN_WARNING "Overriding previously set SMP ops\n");

    mp_ops = ops;
}

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

    memcpy(c, &boot_cpu_data, sizeof(struct sh_cpuinfo));

    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;
    mp_ops->prepare_cpus(max_cpus);

#ifndef CONFIG_HOTPLUG_CPU
    init_cpu_present(cpu_possible_mask);
#endif
}

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

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

    set_cpu_online(cpu, true);
    set_cpu_possible(cpu, true);

    per_cpu(cpu_state, cpu) = CPU_ONLINE;
}

#ifdef CONFIG_HOTPLUG_CPU
void native_cpu_die(unsigned int cpu)
{
    unsigned int i;

    for (i = 0; i < 10; i++) {
        smp_rmb();
        if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
            if (system_state == SYSTEM_RUNNING)
                pr_info("CPU %u is now offline\n", cpu);

            return;
        }

        msleep(100);
    }

    pr_err("CPU %u didn't die...\n", cpu);
}

int native_cpu_disable(unsigned int cpu)
{
    return cpu == 0 ? -EPERM : 0;
}

void play_dead_common(void)
{
    idle_task_exit();
    irq_ctx_exit(raw_smp_processor_id());
    mb();

    __get_cpu_var(cpu_state) = CPU_DEAD;
    local_irq_disable();
}

void native_play_dead(void)
{
    play_dead_common();
}

int __cpu_disable(void)
{
    unsigned int cpu = smp_processor_id();
    int ret;

    ret = mp_ops->cpu_disable(cpu);
    if (ret)
        return ret;

    /*
     * Take this CPU offline.  Once we clear this, we can't return,
     * and we must not schedule until we're ready to give up the cpu.
     */
    set_cpu_online(cpu, false);

    /*
     * OK - migrate IRQs away from this CPU
     */
    migrate_irqs();

    /*
     * Stop the local timer for this CPU.
     */
    local_timer_stop(cpu);

    /*
     * Flush user cache and TLB mappings, and then remove this CPU
     * from the vm mask set of all processes.
     */
    flush_cache_all();
    local_flush_tlb_all();

    clear_tasks_mm_cpumask(cpu);

    return 0;
}
#else /* ... !CONFIG_HOTPLUG_CPU */
int native_cpu_disable(unsigned int cpu)
{
    return -ENOSYS;
}

void native_cpu_die(unsigned int cpu)
{
    /* We said "no" in __cpu_disable */
    BUG();
}

void native_play_dead(void)
{
    BUG();
}
#endif

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

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

    per_cpu_trap_init();

    preempt_disable();

    notify_cpu_starting(cpu);

    local_irq_enable();

    /* Enable local timers */
    local_timer_setup(cpu);
    calibrate_delay();

    smp_store_cpu_info(cpu);

    set_cpu_online(cpu, true);
    per_cpu(cpu_state, cpu) = CPU_ONLINE;

    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;

    per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;

    /* 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_icache_range((unsigned long)&stack_start,
               (unsigned long)&stack_start + sizeof(stack_start));
    wmb();

    mp_ops->start_cpu(cpu, (unsigned long)_stext);

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

        udelay(10);
        barrier();
    }

    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)
{
    mp_ops->send_ipi(cpu, SMP_MSG_RESCHEDULE);
}

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

void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
    int cpu;

    for_each_cpu(cpu, mask)
        mp_ops->send_ipi(cpu, SMP_MSG_FUNCTION);
}

void arch_send_call_function_single_ipi(int cpu)
{
    mp_ops->send_ipi(cpu, SMP_MSG_FUNCTION_SINGLE);
}

void smp_timer_broadcast(const struct cpumask *mask)
{
    int cpu;

    for_each_cpu(cpu, mask)
        mp_ops->send_ipi(cpu, SMP_MSG_TIMER);
}

static void ipi_timer(void)
{
    irq_enter();
    local_timer_interrupt();
    irq_exit();
}

void smp_message_recv(unsigned int msg)
{
    switch (msg) {
    case SMP_MSG_FUNCTION:
        generic_smp_call_function_interrupt();
        break;
    case SMP_MSG_RESCHEDULE:
        scheduler_ipi();
        break;
    case SMP_MSG_FUNCTION_SINGLE:
        generic_smp_call_function_single_interrupt();
        break;
    case SMP_MSG_TIMER:
        ipi_timer();
        break;
    default:
        printk(KERN_WARNING "SMP %d: %s(): unknown IPI %d\n",
               smp_processor_id(), __func__, msg);
        break;
    }
}

/* 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);
}