grub/grub-core/commands/i386/pc/acpi.c
Andrei Borzenkov 07258815e9 acpi: do not skip BIOS scan if EBDA length is zero
EBDA layout is not standardized so we cannot assume first two bytes
are length. Neither is it required by ACPI standard. HP 8710W is known
to contain zeroes here.

Closes: 45002
2015-05-08 06:15:16 +03:00

83 lines
3.2 KiB
C

/* acpi.c - get acpi tables. */
/*
* GRUB -- GRand Unified Bootloader
* 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/>.
*/
#include <grub/acpi.h>
#include <grub/misc.h>
struct grub_acpi_rsdp_v10 *
grub_machine_acpi_get_rsdpv1 (void)
{
int ebda_len;
grub_uint8_t *ebda, *ptr;
grub_dprintf ("acpi", "Looking for RSDP. Scanning EBDA\n");
ebda = (grub_uint8_t *) ((* ((grub_uint16_t *) 0x40e)) << 4);
ebda_len = * (grub_uint16_t *) ebda;
if (! ebda_len) /* FIXME do we really need this check? */
goto scan_bios;
for (ptr = ebda; ptr < ebda + 0x400; ptr += 16)
if (grub_memcmp (ptr, GRUB_RSDP_SIGNATURE, GRUB_RSDP_SIGNATURE_SIZE) == 0
&& grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
&& ((struct grub_acpi_rsdp_v10 *) ptr)->revision == 0)
return (struct grub_acpi_rsdp_v10 *) ptr;
scan_bios:
grub_dprintf ("acpi", "Looking for RSDP. Scanning BIOS\n");
for (ptr = (grub_uint8_t *) 0xe0000; ptr < (grub_uint8_t *) 0x100000;
ptr += 16)
if (grub_memcmp (ptr, GRUB_RSDP_SIGNATURE, GRUB_RSDP_SIGNATURE_SIZE) == 0
&& grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
&& ((struct grub_acpi_rsdp_v10 *) ptr)->revision == 0)
return (struct grub_acpi_rsdp_v10 *) ptr;
return 0;
}
struct grub_acpi_rsdp_v20 *
grub_machine_acpi_get_rsdpv2 (void)
{
int ebda_len;
grub_uint8_t *ebda, *ptr;
grub_dprintf ("acpi", "Looking for RSDP. Scanning EBDA\n");
ebda = (grub_uint8_t *) ((* ((grub_uint16_t *) 0x40e)) << 4);
ebda_len = * (grub_uint16_t *) ebda;
if (! ebda_len) /* FIXME do we really need this check? */
goto scan_bios;
for (ptr = ebda; ptr < ebda + 0x400; ptr += 16)
if (grub_memcmp (ptr, GRUB_RSDP_SIGNATURE, GRUB_RSDP_SIGNATURE_SIZE) == 0
&& grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
&& ((struct grub_acpi_rsdp_v10 *) ptr)->revision != 0
&& ((struct grub_acpi_rsdp_v20 *) ptr)->length < 1024
&& grub_byte_checksum (ptr, ((struct grub_acpi_rsdp_v20 *) ptr)->length)
== 0)
return (struct grub_acpi_rsdp_v20 *) ptr;
scan_bios:
grub_dprintf ("acpi", "Looking for RSDP. Scanning BIOS\n");
for (ptr = (grub_uint8_t *) 0xe0000; ptr < (grub_uint8_t *) 0x100000;
ptr += 16)
if (grub_memcmp (ptr, GRUB_RSDP_SIGNATURE, GRUB_RSDP_SIGNATURE_SIZE) == 0
&& grub_byte_checksum (ptr, sizeof (struct grub_acpi_rsdp_v10)) == 0
&& ((struct grub_acpi_rsdp_v10 *) ptr)->revision != 0
&& ((struct grub_acpi_rsdp_v20 *) ptr)->length < 1024
&& grub_byte_checksum (ptr, ((struct grub_acpi_rsdp_v20 *) ptr)->length)
== 0)
return (struct grub_acpi_rsdp_v20 *) ptr;
return 0;
}