mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race

[linux/fpc-iii.git] / arch / mn10300 / kernel / smp.c

/* SMP support routines.
 *
 * Copyright (C) 2006-2008 Panasonic Corporation
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * 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.
 */

#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/cpumask.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched/mm.h>
#include <linux/sched/task.h>
#include <linux/profile.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <asm/tlbflush.h>
#include <asm/bitops.h>
#include <asm/processor.h>
#include <asm/bug.h>
#include <asm/exceptions.h>
#include <asm/hardirq.h>
#include <asm/fpu.h>
#include <asm/mmu_context.h>
#include <asm/thread_info.h>
#include <asm/cpu-regs.h>
#include <asm/intctl-regs.h>
#include "internal.h"

#ifdef CONFIG_HOTPLUG_CPU
#include <asm/cacheflush.h>

static unsigned long sleep_mode[NR_CPUS];

static void run_sleep_cpu(unsigned int cpu);
static void run_wakeup_cpu(unsigned int cpu);
#endif /* CONFIG_HOTPLUG_CPU */

/*
 * Debug Message function
 */

#undef DEBUG_SMP
#ifdef DEBUG_SMP
#define Dprintk(fmt, ...) printk(KERN_DEBUG fmt, ##__VA_ARGS__)
#else
#define Dprintk(fmt, ...) no_printk(KERN_DEBUG fmt, ##__VA_ARGS__)
#endif

/* timeout value in msec for smp_nmi_call_function. zero is no timeout. */
#define CALL_FUNCTION_NMI_IPI_TIMEOUT   0

/*
 * Structure and data for smp_nmi_call_function().
 */
struct nmi_call_data_struct {
        smp_call_func_t func;
        void            *info;
        cpumask_t       started;
        cpumask_t       finished;
        int             wait;
        char            size_alignment[0]
        __attribute__ ((__aligned__(SMP_CACHE_BYTES)));
} __attribute__ ((__aligned__(SMP_CACHE_BYTES)));

static DEFINE_SPINLOCK(smp_nmi_call_lock);
static struct nmi_call_data_struct *nmi_call_data;

/*
 * Data structures and variables
 */
static cpumask_t cpu_callin_map;        /* Bitmask of callin CPUs */
static cpumask_t cpu_callout_map;       /* Bitmask of callout CPUs */
cpumask_t cpu_boot_map;                 /* Bitmask of boot APs */
unsigned long start_stack[NR_CPUS - 1];

/*
 * Per CPU parameters
 */
struct mn10300_cpuinfo cpu_data[NR_CPUS] __cacheline_aligned;

static int cpucount;                    /* The count of boot CPUs */
static cpumask_t smp_commenced_mask;
cpumask_t cpu_initialized __initdata = CPU_MASK_NONE;

/*
 * Function Prototypes
 */
static int do_boot_cpu(int);
static void smp_show_cpu_info(int cpu_id);
static void smp_callin(void);
static void smp_online(void);
static void smp_store_cpu_info(int);
static void smp_cpu_init(void);
static void smp_tune_scheduling(void);
static void send_IPI_mask(const cpumask_t *cpumask, int irq);
static void init_ipi(void);

/*
 * IPI Initialization interrupt definitions
 */
static void mn10300_ipi_disable(unsigned int irq);
static void mn10300_ipi_enable(unsigned int irq);
static void mn10300_ipi_chip_disable(struct irq_data *d);
static void mn10300_ipi_chip_enable(struct irq_data *d);
static void mn10300_ipi_ack(struct irq_data *d);
static void mn10300_ipi_nop(struct irq_data *d);

static struct irq_chip mn10300_ipi_type = {
        .name           = "cpu_ipi",
        .irq_disable    = mn10300_ipi_chip_disable,
        .irq_enable     = mn10300_ipi_chip_enable,
        .irq_ack        = mn10300_ipi_ack,
        .irq_eoi        = mn10300_ipi_nop
};

static irqreturn_t smp_reschedule_interrupt(int irq, void *dev_id);
static irqreturn_t smp_call_function_interrupt(int irq, void *dev_id);

static struct irqaction reschedule_ipi = {
        .handler        = smp_reschedule_interrupt,
        .flags          = IRQF_NOBALANCING,
        .name           = "smp reschedule IPI"
};
static struct irqaction call_function_ipi = {
        .handler        = smp_call_function_interrupt,
        .flags          = IRQF_NOBALANCING,
        .name           = "smp call function IPI"
};

#if !defined(CONFIG_GENERIC_CLOCKEVENTS) || defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)
static irqreturn_t smp_ipi_timer_interrupt(int irq, void *dev_id);
static struct irqaction local_timer_ipi = {
        .handler        = smp_ipi_timer_interrupt,
        .flags          = IRQF_NOBALANCING,
        .name           = "smp local timer IPI"
};
#endif

/**
 * init_ipi - Initialise the IPI mechanism
 */
static void init_ipi(void)
{
        unsigned long flags;
        u16 tmp16;

        /* set up the reschedule IPI */
        irq_set_chip_and_handler(RESCHEDULE_IPI, &mn10300_ipi_type,
                                 handle_percpu_irq);
        setup_irq(RESCHEDULE_IPI, &reschedule_ipi);
        set_intr_level(RESCHEDULE_IPI, RESCHEDULE_GxICR_LV);
        mn10300_ipi_enable(RESCHEDULE_IPI);

        /* set up the call function IPI */
        irq_set_chip_and_handler(CALL_FUNC_SINGLE_IPI, &mn10300_ipi_type,
                                 handle_percpu_irq);
        setup_irq(CALL_FUNC_SINGLE_IPI, &call_function_ipi);
        set_intr_level(CALL_FUNC_SINGLE_IPI, CALL_FUNCTION_GxICR_LV);
        mn10300_ipi_enable(CALL_FUNC_SINGLE_IPI);

        /* set up the local timer IPI */
#if !defined(CONFIG_GENERIC_CLOCKEVENTS) || \
    defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)
        irq_set_chip_and_handler(LOCAL_TIMER_IPI, &mn10300_ipi_type,
                                 handle_percpu_irq);
        setup_irq(LOCAL_TIMER_IPI, &local_timer_ipi);
        set_intr_level(LOCAL_TIMER_IPI, LOCAL_TIMER_GxICR_LV);
        mn10300_ipi_enable(LOCAL_TIMER_IPI);
#endif

#ifdef CONFIG_MN10300_CACHE_ENABLED
        /* set up the cache flush IPI */
        irq_set_chip(FLUSH_CACHE_IPI, &mn10300_ipi_type);
        flags = arch_local_cli_save();
        __set_intr_stub(NUM2EXCEP_IRQ_LEVEL(FLUSH_CACHE_GxICR_LV),
                        mn10300_low_ipi_handler);
        GxICR(FLUSH_CACHE_IPI) = FLUSH_CACHE_GxICR_LV | GxICR_DETECT;
        mn10300_ipi_enable(FLUSH_CACHE_IPI);
        arch_local_irq_restore(flags);
#endif

        /* set up the NMI call function IPI */
        irq_set_chip(CALL_FUNCTION_NMI_IPI, &mn10300_ipi_type);
        flags = arch_local_cli_save();
        GxICR(CALL_FUNCTION_NMI_IPI) = GxICR_NMI | GxICR_ENABLE | GxICR_DETECT;
        tmp16 = GxICR(CALL_FUNCTION_NMI_IPI);
        arch_local_irq_restore(flags);

        /* set up the SMP boot IPI */
        flags = arch_local_cli_save();
        __set_intr_stub(NUM2EXCEP_IRQ_LEVEL(SMP_BOOT_GxICR_LV),
                        mn10300_low_ipi_handler);
        arch_local_irq_restore(flags);

#ifdef CONFIG_KERNEL_DEBUGGER
        irq_set_chip(DEBUGGER_NMI_IPI, &mn10300_ipi_type);
#endif
}

/**
 * mn10300_ipi_shutdown - Shut down handling of an IPI
 * @irq: The IPI to be shut down.
 */
static void mn10300_ipi_shutdown(unsigned int irq)
{
        unsigned long flags;
        u16 tmp;

        flags = arch_local_cli_save();

        tmp = GxICR(irq);
        GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_DETECT;
        tmp = GxICR(irq);

        arch_local_irq_restore(flags);
}

/**
 * mn10300_ipi_enable - Enable an IPI
 * @irq: The IPI to be enabled.
 */
static void mn10300_ipi_enable(unsigned int irq)
{
        unsigned long flags;
        u16 tmp;

        flags = arch_local_cli_save();

        tmp = GxICR(irq);
        GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE;
        tmp = GxICR(irq);

        arch_local_irq_restore(flags);
}

static void mn10300_ipi_chip_enable(struct irq_data *d)
{
        mn10300_ipi_enable(d->irq);
}

/**
 * mn10300_ipi_disable - Disable an IPI
 * @irq: The IPI to be disabled.
 */
static void mn10300_ipi_disable(unsigned int irq)
{
        unsigned long flags;
        u16 tmp;

        flags = arch_local_cli_save();

        tmp = GxICR(irq);
        GxICR(irq) = tmp & GxICR_LEVEL;
        tmp = GxICR(irq);

        arch_local_irq_restore(flags);
}

static void mn10300_ipi_chip_disable(struct irq_data *d)
{
        mn10300_ipi_disable(d->irq);
}


/**
 * mn10300_ipi_ack - Acknowledge an IPI interrupt in the PIC
 * @irq: The IPI to be acknowledged.
 *
 * Clear the interrupt detection flag for the IPI on the appropriate interrupt
 * channel in the PIC.
 */
static void mn10300_ipi_ack(struct irq_data *d)
{
        unsigned int irq = d->irq;
        unsigned long flags;
        u16 tmp;

        flags = arch_local_cli_save();
        GxICR_u8(irq) = GxICR_DETECT;
        tmp = GxICR(irq);
        arch_local_irq_restore(flags);
}

/**
 * mn10300_ipi_nop - Dummy IPI action
 * @irq: The IPI to be acted upon.
 */
static void mn10300_ipi_nop(struct irq_data *d)
{
}

/**
 * send_IPI_mask - Send IPIs to all CPUs in list
 * @cpumask: The list of CPUs to target.
 * @irq: The IPI request to be sent.
 *
 * Send the specified IPI to all the CPUs in the list, not waiting for them to
 * finish before returning.  The caller is responsible for synchronisation if
 * that is needed.
 */
static void send_IPI_mask(const cpumask_t *cpumask, int irq)
{
        int i;
        u16 tmp;

        for (i = 0; i < NR_CPUS; i++) {
                if (cpumask_test_cpu(i, cpumask)) {
                        /* send IPI */
                        tmp = CROSS_GxICR(irq, i);
                        CROSS_GxICR(irq, i) =
                                tmp | GxICR_REQUEST | GxICR_DETECT;
                        tmp = CROSS_GxICR(irq, i); /* flush write buffer */
                }
        }
}

/**
 * send_IPI_self - Send an IPI to this CPU.
 * @irq: The IPI request to be sent.
 *
 * Send the specified IPI to the current CPU.
 */
void send_IPI_self(int irq)
{
        send_IPI_mask(cpumask_of(smp_processor_id()), irq);
}

/**
 * send_IPI_allbutself - Send IPIs to all the other CPUs.
 * @irq: The IPI request to be sent.
 *
 * Send the specified IPI to all CPUs in the system barring the current one,
 * not waiting for them to finish before returning.  The caller is responsible
 * for synchronisation if that is needed.
 */
void send_IPI_allbutself(int irq)
{
        cpumask_t cpumask;

        cpumask_copy(&cpumask, cpu_online_mask);
        cpumask_clear_cpu(smp_processor_id(), &cpumask);
        send_IPI_mask(&cpumask, irq);
}

void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
        BUG();
        /*send_IPI_mask(mask, CALL_FUNCTION_IPI);*/
}

void arch_send_call_function_single_ipi(int cpu)
{
        send_IPI_mask(cpumask_of(cpu), CALL_FUNC_SINGLE_IPI);
}

/**
 * smp_send_reschedule - Send reschedule IPI to a CPU
 * @cpu: The CPU to target.
 */
void smp_send_reschedule(int cpu)
{
        send_IPI_mask(cpumask_of(cpu), RESCHEDULE_IPI);
}

/**
 * smp_nmi_call_function - Send a call function NMI IPI to all CPUs
 * @func: The function to ask to be run.
 * @info: The context data to pass to that function.
 * @wait: If true, wait (atomically) until function is run on all CPUs.
 *
 * Send a non-maskable request to all CPUs in the system, requesting them to
 * run the specified function with the given context data, and, potentially, to
 * wait for completion of that function on all CPUs.
 *
 * Returns 0 if successful, -ETIMEDOUT if we were asked to wait, but hit the
 * timeout.
 */
int smp_nmi_call_function(smp_call_func_t func, void *info, int wait)
{
        struct nmi_call_data_struct data;
        unsigned long flags;
        unsigned int cnt;
        int cpus, ret = 0;

        cpus = num_online_cpus() - 1;
        if (cpus < 1)
                return 0;

        data.func = func;
        data.info = info;
        cpumask_copy(&data.started, cpu_online_mask);
        cpumask_clear_cpu(smp_processor_id(), &data.started);
        data.wait = wait;
        if (wait)
                data.finished = data.started;

        spin_lock_irqsave(&smp_nmi_call_lock, flags);
        nmi_call_data = &data;
        smp_mb();

        /* Send a message to all other CPUs and wait for them to respond */
        send_IPI_allbutself(CALL_FUNCTION_NMI_IPI);

        /* Wait for response */
        if (CALL_FUNCTION_NMI_IPI_TIMEOUT > 0) {
                for (cnt = 0;
                     cnt < CALL_FUNCTION_NMI_IPI_TIMEOUT &&
                             !cpumask_empty(&data.started);
                     cnt++)
                        mdelay(1);

                if (wait && cnt < CALL_FUNCTION_NMI_IPI_TIMEOUT) {
                        for (cnt = 0;
                             cnt < CALL_FUNCTION_NMI_IPI_TIMEOUT &&
                                     !cpumask_empty(&data.finished);
                             cnt++)
                                mdelay(1);
                }

                if (cnt >= CALL_FUNCTION_NMI_IPI_TIMEOUT)
                        ret = -ETIMEDOUT;

        } else {
                /* If timeout value is zero, wait until cpumask has been
                 * cleared */
                while (!cpumask_empty(&data.started))
                        barrier();
                if (wait)
                        while (!cpumask_empty(&data.finished))
                                barrier();
        }

        spin_unlock_irqrestore(&smp_nmi_call_lock, flags);
        return ret;
}

/**
 * smp_jump_to_debugger - Make other CPUs enter the debugger by sending an IPI
 *
 * Send a non-maskable request to all other CPUs in the system, instructing
 * them to jump into the debugger.  The caller is responsible for checking that
 * the other CPUs responded to the instruction.
 *
 * The caller should make sure that this CPU's debugger IPI is disabled.
 */
void smp_jump_to_debugger(void)
{
        if (num_online_cpus() > 1)
                /* Send a message to all other CPUs */
                send_IPI_allbutself(DEBUGGER_NMI_IPI);
}

/**
 * stop_this_cpu - Callback to stop a CPU.
 * @unused: Callback context (ignored).
 */
void stop_this_cpu(void *unused)
{
        static volatile int stopflag;
        unsigned long flags;

#ifdef CONFIG_GDBSTUB
        /* In case of single stepping smp_send_stop by other CPU,
         * clear procindebug to avoid deadlock.
         */
        atomic_set(&procindebug[smp_processor_id()], 0);
#endif  /* CONFIG_GDBSTUB */

        flags = arch_local_cli_save();
        set_cpu_online(smp_processor_id(), false);

        while (!stopflag)
                cpu_relax();

        set_cpu_online(smp_processor_id(), true);
        arch_local_irq_restore(flags);
}

/**
 * smp_send_stop - Send a stop request to all CPUs.
 */
void smp_send_stop(void)
{
        smp_nmi_call_function(stop_this_cpu, NULL, 0);
}

/**
 * smp_reschedule_interrupt - Reschedule IPI handler
 * @irq: The interrupt number.
 * @dev_id: The device ID.
 *
 * Returns IRQ_HANDLED to indicate we handled the interrupt successfully.
 */
static irqreturn_t smp_reschedule_interrupt(int irq, void *dev_id)
{
        scheduler_ipi();
        return IRQ_HANDLED;
}

/**
 * smp_call_function_interrupt - Call function IPI handler
 * @irq: The interrupt number.
 * @dev_id: The device ID.
 *
 * Returns IRQ_HANDLED to indicate we handled the interrupt successfully.
 */
static irqreturn_t smp_call_function_interrupt(int irq, void *dev_id)
{
        /* generic_smp_call_function_interrupt(); */
        generic_smp_call_function_single_interrupt();
        return IRQ_HANDLED;
}

/**
 * smp_nmi_call_function_interrupt - Non-maskable call function IPI handler
 */
void smp_nmi_call_function_interrupt(void)
{
        smp_call_func_t func = nmi_call_data->func;
        void *info = nmi_call_data->info;
        int wait = nmi_call_data->wait;

        /* Notify the initiating CPU that I've grabbed the data and am about to
         * execute the function
         */
        smp_mb();
        cpumask_clear_cpu(smp_processor_id(), &nmi_call_data->started);
        (*func)(info);

        if (wait) {
                smp_mb();
                cpumask_clear_cpu(smp_processor_id(),
                                  &nmi_call_data->finished);
        }
}

#if !defined(CONFIG_GENERIC_CLOCKEVENTS) || \
    defined(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST)
/**
 * smp_ipi_timer_interrupt - Local timer IPI handler
 * @irq: The interrupt number.
 * @dev_id: The device ID.
 *
 * Returns IRQ_HANDLED to indicate we handled the interrupt successfully.
 */
static irqreturn_t smp_ipi_timer_interrupt(int irq, void *dev_id)
{
        return local_timer_interrupt();
}
#endif

void __init smp_init_cpus(void)
{
        int i;
        for (i = 0; i < NR_CPUS; i++) {
                set_cpu_possible(i, true);
                set_cpu_present(i, true);
        }
}

/**
 * smp_cpu_init - Initialise AP in start_secondary.
 *
 * For this Application Processor, set up init_mm, initialise FPU and set
 * interrupt level 0-6 setting.
 */
static void __init smp_cpu_init(void)
{
        unsigned long flags;
        int cpu_id = smp_processor_id();
        u16 tmp16;

        if (test_and_set_bit(cpu_id, &cpu_initialized)) {
                printk(KERN_WARNING "CPU#%d already initialized!\n", cpu_id);
                for (;;)
                        local_irq_enable();
        }
        printk(KERN_INFO "Initializing CPU#%d\n", cpu_id);

        mmgrab(&init_mm);
        current->active_mm = &init_mm;
        BUG_ON(current->mm);

        enter_lazy_tlb(&init_mm, current);

        /* Force FPU initialization */
        clear_using_fpu(current);

        GxICR(CALL_FUNC_SINGLE_IPI) = CALL_FUNCTION_GxICR_LV | GxICR_DETECT;
        mn10300_ipi_enable(CALL_FUNC_SINGLE_IPI);

        GxICR(LOCAL_TIMER_IPI) = LOCAL_TIMER_GxICR_LV | GxICR_DETECT;
        mn10300_ipi_enable(LOCAL_TIMER_IPI);

        GxICR(RESCHEDULE_IPI) = RESCHEDULE_GxICR_LV | GxICR_DETECT;
        mn10300_ipi_enable(RESCHEDULE_IPI);

#ifdef CONFIG_MN10300_CACHE_ENABLED
        GxICR(FLUSH_CACHE_IPI) = FLUSH_CACHE_GxICR_LV | GxICR_DETECT;
        mn10300_ipi_enable(FLUSH_CACHE_IPI);
#endif

        mn10300_ipi_shutdown(SMP_BOOT_IRQ);

        /* Set up the non-maskable call function IPI */
        flags = arch_local_cli_save();
        GxICR(CALL_FUNCTION_NMI_IPI) = GxICR_NMI | GxICR_ENABLE | GxICR_DETECT;
        tmp16 = GxICR(CALL_FUNCTION_NMI_IPI);
        arch_local_irq_restore(flags);
}

/**
 * smp_prepare_cpu_init - Initialise CPU in startup_secondary
 *
 * Set interrupt level 0-6 setting and init ICR of the kernel debugger.
 */
void smp_prepare_cpu_init(void)
{
        int loop;

        /* Set the interrupt vector registers */
        IVAR0 = EXCEP_IRQ_LEVEL0;
        IVAR1 = EXCEP_IRQ_LEVEL1;
        IVAR2 = EXCEP_IRQ_LEVEL2;
        IVAR3 = EXCEP_IRQ_LEVEL3;
        IVAR4 = EXCEP_IRQ_LEVEL4;
        IVAR5 = EXCEP_IRQ_LEVEL5;
        IVAR6 = EXCEP_IRQ_LEVEL6;

        /* Disable all interrupts and set to priority 6 (lowest) */
        for (loop = 0; loop < GxICR_NUM_IRQS; loop++)
                GxICR(loop) = GxICR_LEVEL_6 | GxICR_DETECT;

#ifdef CONFIG_KERNEL_DEBUGGER
        /* initialise the kernel debugger interrupt */
        do {
                unsigned long flags;
                u16 tmp16;

                flags = arch_local_cli_save();
                GxICR(DEBUGGER_NMI_IPI) = GxICR_NMI | GxICR_ENABLE | GxICR_DETECT;
                tmp16 = GxICR(DEBUGGER_NMI_IPI);
                arch_local_irq_restore(flags);
        } while (0);
#endif
}

/**
 * start_secondary - Activate a secondary CPU (AP)
 * @unused: Thread parameter (ignored).
 */
int __init start_secondary(void *unused)
{
        smp_cpu_init();
        smp_callin();
        while (!cpumask_test_cpu(smp_processor_id(), &smp_commenced_mask))
                cpu_relax();

        local_flush_tlb();
        preempt_disable();
        smp_online();

#ifdef CONFIG_GENERIC_CLOCKEVENTS
        init_clockevents();
#endif
        cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
        return 0;
}

/**
 * smp_prepare_cpus - Boot up secondary CPUs (APs)
 * @max_cpus: Maximum number of CPUs to boot.
 *
 * Call do_boot_cpu, and boot up APs.
 */
void __init smp_prepare_cpus(unsigned int max_cpus)
{
        int phy_id;

        /* Setup boot CPU information */
        smp_store_cpu_info(0);
        smp_tune_scheduling();

        init_ipi();

        /* If SMP should be disabled, then finish */
        if (max_cpus == 0) {
                printk(KERN_INFO "SMP mode deactivated.\n");
                goto smp_done;
        }

        /* Boot secondary CPUs (for which phy_id > 0) */
        for (phy_id = 0; phy_id < NR_CPUS; phy_id++) {
                /* Don't boot primary CPU */
                if (max_cpus <= cpucount + 1)
                        continue;
                if (phy_id != 0)
                        do_boot_cpu(phy_id);
                set_cpu_possible(phy_id, true);
                smp_show_cpu_info(phy_id);
        }

smp_done:
        Dprintk("Boot done.\n");
}

/**
 * smp_store_cpu_info - Save a CPU's information
 * @cpu: The CPU to save for.
 *
 * Save boot_cpu_data and jiffy for the specified CPU.
 */
static void __init smp_store_cpu_info(int cpu)
{
        struct mn10300_cpuinfo *ci = &cpu_data[cpu];

        *ci = boot_cpu_data;
        ci->loops_per_jiffy = loops_per_jiffy;
        ci->type = CPUREV;
}

/**
 * smp_tune_scheduling - Set time slice value
 *
 * Nothing to do here.
 */
static void __init smp_tune_scheduling(void)
{
}

/**
 * do_boot_cpu: Boot up one CPU
 * @phy_id: Physical ID of CPU to boot.
 *
 * Send an IPI to a secondary CPU to boot it.  Returns 0 on success, 1
 * otherwise.
 */
static int __init do_boot_cpu(int phy_id)
{
        struct task_struct *idle;
        unsigned long send_status, callin_status;
        int timeout, cpu_id;

        send_status = GxICR_REQUEST;
        callin_status = 0;
        timeout = 0;
        cpu_id = phy_id;

        cpucount++;

        /* Create idle thread for this CPU */
        idle = fork_idle(cpu_id);
        if (IS_ERR(idle))
                panic("Failed fork for CPU#%d.", cpu_id);

        idle->thread.pc = (unsigned long)start_secondary;

        printk(KERN_NOTICE "Booting CPU#%d\n", cpu_id);
        start_stack[cpu_id - 1] = idle->thread.sp;

        task_thread_info(idle)->cpu = cpu_id;

        /* Send boot IPI to AP */
        send_IPI_mask(cpumask_of(phy_id), SMP_BOOT_IRQ);

        Dprintk("Waiting for send to finish...\n");

        /* Wait for AP's IPI receive in 100[ms] */
        do {
                udelay(1000);
                send_status =
                        CROSS_GxICR(SMP_BOOT_IRQ, phy_id) & GxICR_REQUEST;
        } while (send_status == GxICR_REQUEST && timeout++ < 100);

        Dprintk("Waiting for cpu_callin_map.\n");

        if (send_status == 0) {
                /* Allow AP to start initializing */
                cpumask_set_cpu(cpu_id, &cpu_callout_map);

                /* Wait for setting cpu_callin_map */
                timeout = 0;
                do {
                        udelay(1000);
                        callin_status = cpumask_test_cpu(cpu_id,
                                                         &cpu_callin_map);
                } while (callin_status == 0 && timeout++ < 5000);

                if (callin_status == 0)
                        Dprintk("Not responding.\n");
        } else {
                printk(KERN_WARNING "IPI not delivered.\n");
        }

        if (send_status == GxICR_REQUEST || callin_status == 0) {
                cpumask_clear_cpu(cpu_id, &cpu_callout_map);
                cpumask_clear_cpu(cpu_id, &cpu_callin_map);
                cpumask_clear_cpu(cpu_id, &cpu_initialized);
                cpucount--;
                return 1;
        }
        return 0;
}

/**
 * smp_show_cpu_info - Show SMP CPU information
 * @cpu: The CPU of interest.
 */
static void __init smp_show_cpu_info(int cpu)
{
        struct mn10300_cpuinfo *ci = &cpu_data[cpu];

        printk(KERN_INFO
               "CPU#%d : ioclk speed: %lu.%02luMHz : bogomips : %lu.%02lu\n",
               cpu,
               MN10300_IOCLK / 1000000,
               (MN10300_IOCLK / 10000) % 100,
               ci->loops_per_jiffy / (500000 / HZ),
               (ci->loops_per_jiffy / (5000 / HZ)) % 100);
}

/**
 * smp_callin - Set cpu_callin_map of the current CPU ID
 */
static void __init smp_callin(void)
{
        unsigned long timeout;
        int cpu;

        cpu = smp_processor_id();
        timeout = jiffies + (2 * HZ);

        if (cpumask_test_cpu(cpu, &cpu_callin_map)) {
                printk(KERN_ERR "CPU#%d already present.\n", cpu);
                BUG();
        }
        Dprintk("CPU#%d waiting for CALLOUT\n", cpu);

        /* Wait for AP startup 2s total */
        while (time_before(jiffies, timeout)) {
                if (cpumask_test_cpu(cpu, &cpu_callout_map))
                        break;
                cpu_relax();
        }

        if (!time_before(jiffies, timeout)) {
                printk(KERN_ERR
                       "BUG: CPU#%d started up but did not get a callout!\n",
                       cpu);
                BUG();
        }

#ifdef CONFIG_CALIBRATE_DELAY
        calibrate_delay();              /* Get our bogomips */
#endif

        /* Save our processor parameters */
        smp_store_cpu_info(cpu);

        /* Allow the boot processor to continue */
        cpumask_set_cpu(cpu, &cpu_callin_map);
}

/**
 * smp_online - Set cpu_online_mask
 */
static void __init smp_online(void)
{
        int cpu;

        cpu = smp_processor_id();

        notify_cpu_starting(cpu);

        set_cpu_online(cpu, true);

        local_irq_enable();
}

/**
 * smp_cpus_done -
 * @max_cpus: Maximum CPU count.
 *
 * Do nothing.
 */
void __init smp_cpus_done(unsigned int max_cpus)
{
}

/*
 * smp_prepare_boot_cpu - Set up stuff for the boot processor.
 *
 * Set up the cpu_online_mask, cpu_callout_map and cpu_callin_map of the boot
 * processor (CPU 0).
 */
void smp_prepare_boot_cpu(void)
{
        cpumask_set_cpu(0, &cpu_callout_map);
        cpumask_set_cpu(0, &cpu_callin_map);
        current_thread_info()->cpu = 0;
}

/*
 * initialize_secondary - Initialise a secondary CPU (Application Processor).
 *
 * Set SP register and jump to thread's PC address.
 */
void initialize_secondary(void)
{
        asm volatile (
                "mov    %0,sp   \n"
                "jmp    (%1)    \n"
                :
                : "a"(current->thread.sp), "a"(current->thread.pc));
}

/**
 * __cpu_up - Set smp_commenced_mask for the nominated CPU
 * @cpu: The target CPU.
 */
int __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
        int timeout;

#ifdef CONFIG_HOTPLUG_CPU
        if (sleep_mode[cpu])
                run_wakeup_cpu(cpu);
#endif /* CONFIG_HOTPLUG_CPU */

        cpumask_set_cpu(cpu, &smp_commenced_mask);

        /* Wait 5s total for a response */
        for (timeout = 0 ; timeout < 5000 ; timeout++) {
                if (cpu_online(cpu))
                        break;
                udelay(1000);
        }

        BUG_ON(!cpu_online(cpu));
        return 0;
}

/**
 * setup_profiling_timer - Set up the profiling timer
 * @multiplier - The frequency multiplier to use
 *
 * The frequency of the profiling timer can be changed by writing a multiplier
 * value into /proc/profile.
 */
int setup_profiling_timer(unsigned int multiplier)
{
        return -EINVAL;
}

/*
 * CPU hotplug routines
 */
#ifdef CONFIG_HOTPLUG_CPU

static DEFINE_PER_CPU(struct cpu, cpu_devices);

static int __init topology_init(void)
{
        int cpu, ret;

        for_each_cpu(cpu) {
                ret = register_cpu(&per_cpu(cpu_devices, cpu), cpu, NULL);
                if (ret)
                        printk(KERN_WARNING
                               "topology_init: register_cpu %d failed (%d)\n",
                               cpu, ret);
        }
        return 0;
}

subsys_initcall(topology_init);

int __cpu_disable(void)
{
        int cpu = smp_processor_id();
        if (cpu == 0)
                return -EBUSY;

        migrate_irqs();
        cpumask_clear_cpu(cpu, &mm_cpumask(current->active_mm));
        return 0;
}

void __cpu_die(unsigned int cpu)
{
        run_sleep_cpu(cpu);
}

#ifdef CONFIG_MN10300_CACHE_ENABLED
static inline void hotplug_cpu_disable_cache(void)
{
        int tmp;
        asm volatile(
                "       movhu   (%1),%0 \n"
                "       and     %2,%0   \n"
                "       movhu   %0,(%1) \n"
                "1:     movhu   (%1),%0 \n"
                "       btst    %3,%0   \n"
                "       bne     1b      \n"
                : "=&r"(tmp)
                : "a"(&CHCTR),
                  "i"(~(CHCTR_ICEN | CHCTR_DCEN)),
                  "i"(CHCTR_ICBUSY | CHCTR_DCBUSY)
                : "memory", "cc");
}

static inline void hotplug_cpu_enable_cache(void)
{
        int tmp;
        asm volatile(
                "movhu  (%1),%0 \n"
                "or     %2,%0   \n"
                "movhu  %0,(%1) \n"
                : "=&r"(tmp)
                : "a"(&CHCTR),
                  "i"(CHCTR_ICEN | CHCTR_DCEN)
                : "memory", "cc");
}

static inline void hotplug_cpu_invalidate_cache(void)
{
        int tmp;
        asm volatile (
                "movhu  (%1),%0 \n"
                "or     %2,%0   \n"
                "movhu  %0,(%1) \n"
                : "=&r"(tmp)
                : "a"(&CHCTR),
                  "i"(CHCTR_ICINV | CHCTR_DCINV)
                : "cc");
}

#else /* CONFIG_MN10300_CACHE_ENABLED */
#define hotplug_cpu_disable_cache()     do {} while (0)
#define hotplug_cpu_enable_cache()      do {} while (0)
#define hotplug_cpu_invalidate_cache()  do {} while (0)
#endif /* CONFIG_MN10300_CACHE_ENABLED */

/**
 * hotplug_cpu_nmi_call_function - Call a function on other CPUs for hotplug
 * @cpumask: List of target CPUs.
 * @func: The function to call on those CPUs.
 * @info: The context data for the function to be called.
 * @wait: Whether to wait for the calls to complete.
 *
 * Non-maskably call a function on another CPU for hotplug purposes.
 *
 * This function must be called with maskable interrupts disabled.
 */
static int hotplug_cpu_nmi_call_function(cpumask_t cpumask,
                                         smp_call_func_t func, void *info,
                                         int wait)
{
        /*
         * The address and the size of nmi_call_func_mask_data
         * need to be aligned on L1_CACHE_BYTES.
         */
        static struct nmi_call_data_struct nmi_call_func_mask_data
                __cacheline_aligned;
        unsigned long start, end;

        start = (unsigned long)&nmi_call_func_mask_data;
        end = start + sizeof(struct nmi_call_data_struct);

        nmi_call_func_mask_data.func = func;
        nmi_call_func_mask_data.info = info;
        nmi_call_func_mask_data.started = cpumask;
        nmi_call_func_mask_data.wait = wait;
        if (wait)
                nmi_call_func_mask_data.finished = cpumask;

        spin_lock(&smp_nmi_call_lock);
        nmi_call_data = &nmi_call_func_mask_data;
        mn10300_local_dcache_flush_range(start, end);
        smp_wmb();

        send_IPI_mask(cpumask, CALL_FUNCTION_NMI_IPI);

        do {
                mn10300_local_dcache_inv_range(start, end);
                barrier();
        } while (!cpumask_empty(&nmi_call_func_mask_data.started));

        if (wait) {
                do {
                        mn10300_local_dcache_inv_range(start, end);
                        barrier();
                } while (!cpumask_empty(&nmi_call_func_mask_data.finished));
        }

        spin_unlock(&smp_nmi_call_lock);
        return 0;
}

static void restart_wakeup_cpu(void)
{
        unsigned int cpu = smp_processor_id();

        cpumask_set_cpu(cpu, &cpu_callin_map);
        local_flush_tlb();
        set_cpu_online(cpu, true);
        smp_wmb();
}

static void prepare_sleep_cpu(void *unused)
{
        sleep_mode[smp_processor_id()] = 1;
        smp_mb();
        mn10300_local_dcache_flush_inv();
        hotplug_cpu_disable_cache();
        hotplug_cpu_invalidate_cache();
}

/* when this function called, IE=0, NMID=0. */
static void sleep_cpu(void *unused)
{
        unsigned int cpu_id = smp_processor_id();
        /*
         * CALL_FUNCTION_NMI_IPI for wakeup_cpu() shall not be requested,
         * before this cpu goes in SLEEP mode.
         */
        do {
                smp_mb();
                __sleep_cpu();
        } while (sleep_mode[cpu_id]);
        restart_wakeup_cpu();
}

static void run_sleep_cpu(unsigned int cpu)
{
        unsigned long flags;
        cpumask_t cpumask;

        cpumask_copy(&cpumask, &cpumask_of(cpu));
        flags = arch_local_cli_save();
        hotplug_cpu_nmi_call_function(cpumask, prepare_sleep_cpu, NULL, 1);
        hotplug_cpu_nmi_call_function(cpumask, sleep_cpu, NULL, 0);
        udelay(1);              /* delay for the cpu to sleep. */
        arch_local_irq_restore(flags);
}

static void wakeup_cpu(void)
{
        hotplug_cpu_invalidate_cache();
        hotplug_cpu_enable_cache();
        smp_mb();
        sleep_mode[smp_processor_id()] = 0;
}

static void run_wakeup_cpu(unsigned int cpu)
{
        unsigned long flags;

        flags = arch_local_cli_save();
#if NR_CPUS == 2
        mn10300_local_dcache_flush_inv();
#else
        /*
         * Before waking up the cpu,
         * all online cpus should stop and flush D-Cache for global data.
         */
#error not support NR_CPUS > 2, when CONFIG_HOTPLUG_CPU=y.
#endif
        hotplug_cpu_nmi_call_function(cpumask_of(cpu), wakeup_cpu, NULL, 1);
        arch_local_irq_restore(flags);
}

#endif /* CONFIG_HOTPLUG_CPU */