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80 lines
1.8 KiB
C
80 lines
1.8 KiB
C
#ifndef _PAGING_H
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#define _PAGING_H
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/*
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* Copyright (C) 2021 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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/**
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* @file
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*
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* Paging
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*
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*/
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#include <stddef.h>
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/** Get CPU features */
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#define CPUID_FEATURES 0x00000001
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/** CPU supports PAE */
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#define CPUID_FEATURE_EDX_PAE 0x00000040
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/* CR0: paging */
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#define CR0_PG 0x80000000
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/* CR4: physical address extensions */
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#define CR4_PAE 0x00000020
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/* Page: present */
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#define PG_P 0x01
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/* Page: read/write */
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#define PG_RW 0x02
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/* Page: user/supervisor */
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#define PG_US 0x04
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/* Page: page size */
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#define PG_PS 0x80
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/** 2MB page size */
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#define PAGE_SIZE_2MB 0x200000
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/** 32-bit address space size */
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#define ADDR_4GB 0x100000000ULL
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/** Saved paging state */
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struct paging_state {
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/** Control register 0 */
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unsigned long cr0;
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/** Control register 3 */
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unsigned long cr3;
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/** Control register 4 */
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unsigned long cr4;
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};
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extern int paging;
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extern void init_paging ( void );
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extern void enable_paging ( struct paging_state *state );
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extern void disable_paging ( struct paging_state *state );
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extern uint64_t relocate_memory_high ( void *start, size_t len );
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#endif /* _PAGING_H */
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