wimboot/wimboot-2.7.3/src/paging.h

   1 #ifndef _PAGING_H
   2 #define _PAGING_H
   3
   4 /*
   5  * Copyright (C) 2021 Michael Brown <mbrown@fensystems.co.uk>.
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  20  * 02110-1301, USA.
  21  */
  22
  23 /**
  24  * @file
  25  *
  26  * Paging
  27  *
  28  */
  29
  30 #include <stddef.h>
  31
  32 /** Get CPU features */
  33 #define CPUID_FEATURES 0x00000001
  34
  35 /** CPU supports PAE */
  36 #define CPUID_FEATURE_EDX_PAE 0x00000040
  37
  38 /* CR0: paging */
  39 #define CR0_PG 0x80000000
  40
  41 /* CR4: physical address extensions */
  42 #define CR4_PAE 0x00000020
  43
  44 /* Page: present */
  45 #define PG_P 0x01
  46
  47 /* Page: read/write */
  48 #define PG_RW 0x02
  49
  50 /* Page: user/supervisor */
  51 #define PG_US 0x04
  52
  53 /* Page: page size */
  54 #define PG_PS 0x80
  55
  56 /** 2MB page size */
  57 #define PAGE_SIZE_2MB 0x200000
  58
  59 /** 32-bit address space size */
  60 #define ADDR_4GB 0x100000000ULL
  61
  62 /** Saved paging state */
  63 struct paging_state {
  64         /** Control register 0 */
  65         unsigned long cr0;
  66         /** Control register 3 */
  67         unsigned long cr3;
  68         /** Control register 4 */
  69         unsigned long cr4;
  70 };
  71
  72 extern int paging;
  73
  74 extern void init_paging ( void );
  75 extern void enable_paging ( struct paging_state *state );
  76 extern void disable_paging ( struct paging_state *state );
  77 extern uint64_t relocate_memory_high ( void *start, size_t len );
  78
  79 #endif /* _PAGING_H */