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/*

 * SMP Support

 *

 * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>

 * Copyright (C) 1999, 2001 David Mosberger-Tang <davidm@hpl.hp.com>

 *

 * Lots of stuff stolen from arch/alpha/kernel/smp.c

 *

 * 01/05/16 Rohit Seth <rohit.seth@intel.com>  IA64-SMP functions. Reorganized

 * the existing code (on the lines of x86 port).

 * 00/09/11 David Mosberger <davidm@hpl.hp.com> Do loops_per_jiffy

 * calibration on each CPU.

 * 00/08/23 Asit Mallick <asit.k.mallick@intel.com> fixed logical processor id

 * 00/03/31 Rohit Seth <rohit.seth@intel.com>   Fixes for Bootstrap Processor

 * & cpu_online_map now gets done here (instead of setup.c)

 * 99/10/05 davidm      Update to bring it in sync with new command-line processing

 *  scheme.

 * 10/13/00 Goutham Rao <goutham.rao@intel.com> Updated smp_call_function and

 *              smp_call_function_single to resend IPI on timeouts

 */

#define __KERNEL_SYSCALLS__

#include <linux/config.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/init.h>

#include <linux/interrupt.h>

#include <linux/smp.h>

#include <linux/kernel_stat.h>

#include <linux/mm.h>

#include <linux/delay.h>

#include <linux/cache.h>

#include <linux/efi.h>

#include <asm/atomic.h>

#include <asm/bitops.h>

#include <asm/current.h>

#include <asm/delay.h>

#include <asm/machvec.h>

#include <asm/io.h>

#include <asm/irq.h>

#include <asm/page.h>

#include <asm/pgalloc.h>

#include <asm/pgtable.h>

#include <asm/processor.h>

#include <asm/ptrace.h>

#include <asm/sal.h>

#include <asm/system.h>

#include <asm/unistd.h>

#include <asm/mca.h>

/* The 'big kernel lock' */

spinlock_t kernel_flag __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;

/*

 * Structure and data for smp_call_function(). This is designed to minimise static memory

 * requirements. It also looks cleaner.

 */

static spinlock_t call_lock = SPIN_LOCK_UNLOCKED;

struct call_data_struct {

        void (*func) (void *info);

        void *info;

        long wait;

        atomic_t started;

        atomic_t finished;

};

static volatile struct call_data_struct *call_data;

#define IPI_CALL_FUNC           0

#define IPI_CPU_STOP            1

static void

stop_this_cpu (void)

{

        extern void cpu_halt (void);

        /*

         * Remove this CPU:

         */

        clear_bit(smp_processor_id(), &cpu_online_map);

        max_xtp();

        __cli();

        cpu_halt();

}

void

handle_IPI (int irq, void *dev_id, struct pt_regs *regs)

{

        int this_cpu = smp_processor_id();

        unsigned long *pending_ipis = &local_cpu_data->ipi.operation;

        unsigned long ops;

        /* Count this now; we may make a call that never returns. */

        local_cpu_data->ipi_count++;

        mb();   /* Order interrupt and bit testing. */

        while ((ops = xchg(pending_ipis, 0)) != 0) {

          mb(); /* Order bit clearing and data access. */

          do {

                unsigned long which;

                which = ffz(~ops);

                ops &= ~(1 << which);

                switch (which) {

                case IPI_CALL_FUNC:

                        {

                                struct call_data_struct *data;

                                void (*func)(void *info);

                                void *info;

                                int wait;

                                /* release the 'pointer lock' */

                                data = (struct call_data_struct *) call_data;

                                func = data->func;

                                info = data->info;

                                wait = data->wait;

                                mb();

                                atomic_inc(&data->started);

                                /* At this point the structure may be gone unless wait is true.  */

                                (*func)(info);

                                /* Notify the sending CPU that the task is done.  */

                                mb();

                                if (wait)

                                        atomic_inc(&data->finished);

                        }

                        break;

                case IPI_CPU_STOP:

                        stop_this_cpu();

                        break;

                default:

                        printk(KERN_CRIT "Unknown IPI on CPU %d: %lu\n", this_cpu, which);

                        break;

                } /* Switch */

          } while (ops);

          mb(); /* Order data access and bit testing. */

        }

}

static inline void

send_IPI_single (int dest_cpu, int op)

{

        set_bit(op, &cpu_data(dest_cpu)->ipi.operation);

        platform_send_ipi(dest_cpu, IA64_IPI_VECTOR, IA64_IPI_DM_INT, 0);

}

static inline void

send_IPI_allbutself (int op)

{

        int i;

        for (i = 0; i < smp_num_cpus; i++) {

                if (i != smp_processor_id())

                        send_IPI_single(i, op);

        }

}

static inline void

send_IPI_all (int op)

{

        int i;

        for (i = 0; i < smp_num_cpus; i++)

                send_IPI_single(i, op);

}

static inline void

send_IPI_self (int op)

{

        send_IPI_single(smp_processor_id(), op);

}

void

smp_send_reschedule (int cpu)

{

        platform_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);

}

void

smp_flush_tlb_all (void)

{

        smp_call_function((void (*)(void *))local_flush_tlb_all, 0, 1, 1);

        local_flush_tlb_all();

}

void

smp_flush_tlb_mm (struct mm_struct *mm)

{

        local_flush_tlb_mm(mm);

        /* this happens for the common case of a single-threaded fork():  */

        if (likely(mm == current->active_mm && atomic_read(&mm->mm_users) == 1))

                return;

        smp_call_function((void (*)(void *))local_flush_tlb_mm, mm, 1, 1);

}

/*

 * Run a function on another CPU

 *  <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 until function has completed on other CPUs.

 *  [RETURNS]   0 on success, else a negative status code.

 *

 * Does not return until the remote CPU is nearly ready to execute <func>

 * or is or has executed.

 */

int

smp_call_function_single (int cpuid, void (*func) (void *info), void *info, int nonatomic,

                          int wait)

{

        struct call_data_struct data;

        int cpus = 1;

        if (cpuid == smp_processor_id()) {

                printk("%s: trying to call self\n", __FUNCTION__);

                return -EBUSY;

        }

        data.func = func;

        data.info = info;

        atomic_set(&data.started, 0);

        data.wait = wait;

        if (wait)

                atomic_set(&data.finished, 0);

        spin_lock_bh(&call_lock);

        call_data = &data;

        mb();   /* ensure store to call_data precedes setting of IPI_CALL_FUNC */

        send_IPI_single(cpuid, IPI_CALL_FUNC);

        /* Wait for response */

        while (atomic_read(&data.started) != cpus)

                barrier();

        if (wait)

                while (atomic_read(&data.finished) != cpus)

                        barrier();

        call_data = NULL;

        spin_unlock_bh(&call_lock);

        return 0;

}

/*

 * this function sends a 'generic call function' IPI to all other CPUs

 * in the system.

 */

/*

 *  [SUMMARY]   Run a function on all 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, you may call it from a bottom half handler.

 */

int

smp_call_function (void (*func) (void *info), void *info, int nonatomic, int wait)

{

        struct call_data_struct data;

        int cpus = smp_num_cpus-1;

        if (!cpus)

                return 0;

        data.func = func;

        data.info = info;

        atomic_set(&data.started, 0);

        data.wait = wait;

        if (wait)

                atomic_set(&data.finished, 0);

        spin_lock_bh(&call_lock);

        call_data = &data;

        mb();   /* ensure store to call_data precedes setting of IPI_CALL_FUNC */

        send_IPI_allbutself(IPI_CALL_FUNC);

        /* Wait for response */

        while (atomic_read(&data.started) != cpus)

                barrier();

        if (wait)

                while (atomic_read(&data.finished) != cpus)

                        barrier();

        call_data = NULL;

        spin_unlock_bh(&call_lock);

        return 0;

}

void

smp_do_timer (struct pt_regs *regs)

{

        int user = user_mode(regs);

        if (--local_cpu_data->prof_counter <= 0) {

                local_cpu_data->prof_counter = local_cpu_data->prof_multiplier;

                update_process_times(user);

        }

}

/*

 * this function calls the 'stop' function on all other CPUs in the system.

 */

void

smp_send_stop (void)

{

        send_IPI_allbutself(IPI_CPU_STOP);

        smp_num_cpus = 1;

}

int __init

setup_profiling_timer (unsigned int multiplier)

{

        return -EINVAL;

}