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/*
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* Copyright (c) 1991 IBM Corporation
* 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,
* and that the name IBM not be used in advertising or publicity
* pertaining to distribution of the software without specific, written
* prior permission.
*
* CARNEGIE MELLON AND IBM ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON AND IBM DISCLAIM 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.
*/
/*
* Global descriptor table.
*/
#include <mach/machine/vm_types.h>
#include "vm_param.h"
#include "seg.h"
#include "gdt.h"
#if PS2
extern unsigned long abios_int_return;
extern unsigned long abios_th_return;
extern char intstack[];
#endif /* PS2 */
struct real_descriptor gdt[GDTSZ];
void
gdt_init()
{
/* Initialize the kernel code and data segment descriptors. */
fill_gdt_descriptor(KERNEL_CS,
LINEAR_MIN_KERNEL_ADDRESS,
LINEAR_MAX_KERNEL_ADDRESS - LINEAR_MIN_KERNEL_ADDRESS - 1,
ACC_PL_K|ACC_CODE_R, SZ_32);
fill_gdt_descriptor(KERNEL_DS,
LINEAR_MIN_KERNEL_ADDRESS,
LINEAR_MAX_KERNEL_ADDRESS - LINEAR_MIN_KERNEL_ADDRESS - 1,
ACC_PL_K|ACC_DATA_W, SZ_32);
/* Load the new GDT. */
{
struct pseudo_descriptor pdesc;
pdesc.limit = sizeof(gdt)-1;
pdesc.linear_base = kvtolin(&gdt);
lgdt(&pdesc);
}
/* Reload all the segment registers from the new GDT.
We must load ds and es with 0 before loading them with KERNEL_DS
because some processors will "optimize out" the loads
if the previous selector values happen to be the same. */
asm volatile("ljmp %0,$1f\n"
"1:\n"
"movw %w2,%%ds\n"
"movw %w2,%%es\n"
"movw %w2,%%fs\n"
"movw %w2,%%gs\n"
"movw %w1,%%ds\n"
"movw %w1,%%es\n"
"movw %w1,%%ss\n"
: : "i" (KERNEL_CS), "r" (KERNEL_DS), "r" (0));
}
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