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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__) */