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/*
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
#ifndef _I386_MP_DESC_H_
#define _I386_MP_DESC_H_
#if MULTIPROCESSOR
/*
* 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 "seg.h"
#include "tss.h"
#include "idt.h"
#include "gdt.h"
#include "ldt.h"
/*
* The descriptor tables are together in a structure
* allocated one per processor (except for the boot processor).
*/
struct mp_desc_table {
struct real_gate idt[IDTSZ]; /* IDT */
struct real_descriptor gdt[GDTSZ]; /* GDT */
struct real_descriptor ldt[LDTSZ]; /* LDT */
struct task_tss ktss;
};
/*
* 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 task_tss *mp_ktss[NCPUS];
/*
* So does the GDT.
*/
extern struct real_descriptor *mp_gdt[NCPUS];
/*
* Each CPU calls this routine to set up its descriptor tables.
*/
extern struct mp_desc_table * mp_desc_init(int);
#endif /* MULTIPROCESSOR */
#endif /* _I386_MP_DESC_H_ */
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