grub/loader/i386/bsd_pagetable.c
2009-05-03 10:14:19 +00:00

88 lines
3.2 KiB
C

/*
* GRUB -- GRand Unified Bootloader
* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
* Copyright (C) 2009 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
/* Based on the code from FreeBSD originally distributed under the
following terms: */
/*-
* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
static void
fill_bsd64_pagetable (grub_uint8_t *target)
{
grub_uint64_t *pt2, *pt3, *pt4;
int i;
#define PG_V 0x001
#define PG_RW 0x002
#define PG_U 0x004
#define PG_PS 0x080
pt4 = (grub_uint64_t *) target;
pt3 = (grub_uint64_t *) (target + 4096);
pt2 = (grub_uint64_t *) (target + 8192);
grub_memset ((char *) target, 0, 4096 * 3);
/*
* This is kinda brutal, but every single 1GB VM memory segment points to
* the same first 1GB of physical memory. But it is how BSD expects
* it to be.
*/
for (i = 0; i < 512; i++)
{
/* Each slot of the level 4 pages points to the same level 3 page */
pt4[i] = (grub_addr_t) &pt3[0];
pt4[i] |= PG_V | PG_RW | PG_U;
/* Each slot of the level 3 pages points to the same level 2 page */
pt3[i] = (grub_addr_t) &pt2[0];
pt3[i] |= PG_V | PG_RW | PG_U;
/* The level 2 page slots are mapped with 2MB pages for 1GB. */
pt2[i] = i * (2 * 1024 * 1024);
pt2[i] |= PG_V | PG_RW | PG_PS | PG_U;
}
}