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/* smp_lock.h: Locking and unlocking the kernel on the Sparc.

 *

 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)

 */

#ifndef __SPARC_SMPLOCK_H

#define __SPARC_SMPLOCK_H

#include <asm/smp.h>

#include <asm/bitops.h>

#include <asm/atops.h>

#include <asm/pgtable.h>

#ifdef __SMP__

/*

 *      Locking the kernel

 */

/* Knock knock... */

extern __inline void lock_kernel(void)

{

        unsigned long flags;

        int proc = smp_processor_id();

        save_flags(flags); cli(); /* need this on sparc? */

        while(ldstub(&kernel_flag)) {

                if(proc == active_kernel_processor)

                        break;

                do {

#ifdef __SMP_PROF__             

                        smp_spins[smp_processor_id()]++;

#endif                  

                        barrier();

                } while(kernel_flag); /* Don't lock the bus more than we have to. */

        }

        active_kernel_processor = proc;

        kernel_counter++;

        restore_flags(flags);

}

/* I want out... */

extern __inline void unlock_kernel(void)

{

        unsigned long flags;

        save_flags(flags); cli(); /* need this on sparc? */

        if(kernel_counter == 0)

                panic("Bogus kernel counter.\n");

        if(!--kernel_counter) {

                active_kernel_processor = NO_PROC_ID;

                kernel_flag = KLOCK_CLEAR;

        }

        restore_flags(flags);

}

#endif /* !(__SPARC_SMPLOCK_H) */

#endif /* (__SMP__) */