Source to osfmk/i386/mp_desc.h

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 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
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/* 
 * Mach Operating System
 * Copyright (c) 1991,1990 Carnegie Mellon University
 * All Rights Reserved.
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 */

/*
 */

#ifndef	_I386_MP_DESC_H_
#define	_I386_MP_DESC_H_

#include <cpus.h>
#include <mach_kdb.h>

/*
 * Multiprocessor i386/i486 systems use a separate copy of the
 * GDT, IDT, LDT, and kernel TSS per processor.  The first three
 * are separate to avoid lock contention: the i386 uses locked
 * memory cycles to access the descriptor tables.  The TSS is
 * separate since each processor needs its own kernel stack,
 * and since using a TSS marks it busy.
 */

#include <i386/seg.h>
#include <i386/tss.h>

/*
 * The descriptor tables are together in a structure
 * allocated one per processor (except for the boot processor).
 * Note that dbtss could be conditionalized on MACH_KDB, but
 * doing so increases misconfiguration risk.
 */
struct mp_desc_table {
	struct fake_descriptor	idt[IDTSZ];	/* IDT */
	struct fake_descriptor	gdt[GDTSZ];	/* GDT */
	struct fake_descriptor	ldt[LDTSZ];	/* LDT */
	struct i386_tss		ktss;
	struct i386_tss		dbtss;
};

/*
 * They are pointed to by a per-processor array.
 */
extern struct mp_desc_table	*mp_desc_table[NCPUS];

/*
 * The kernel TSS gets its own pointer.
 */
extern struct i386_tss		*mp_ktss[NCPUS];
#if	MACH_KDB
extern struct i386_tss		*mp_dbtss[NCPUS];
#endif	/* MACH_KDB */

/*
 * So does the GDT and IDT.
 */
extern struct fake_descriptor	*mp_gdt[NCPUS];
extern struct fake_descriptor	*mp_idt[NCPUS];


/*
 * Each CPU calls this routine to set up its descriptor tables.
 */

extern struct mp_desc_table *	mp_desc_init(
					int		cpu);
extern void			interrupt_stack_alloc(void);

#endif	/* _I386_MP_DESC_H_ */