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2005-07-17 Yoshinori Okuji <okuji@enbug.org>

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* boot/i386/pc/boot.S (boot_drive_check): New label.

	* include/grub/i386/pc/boot.h (GRUB_BOOT_MACHINE_DRIVE_CHECK): New
	macro.

	* util/i386/pc/grub-setup.c (setup): Added a workaround for BIOSes
	which do not pass a boot drive correctly. Copied from GRUB Legacy.
This commit is contained in:
okuji 2005-07-17 14:57:07 +00:00
parent e293232b8e
commit f806d18efd
4 changed files with 42 additions and 4 deletions
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10
ChangeLog
View file

@ -1,3 +1,13 @@
2005-07-17 Yoshinori Okuji <okuji@enbug.org>
* boot/i386/pc/boot.S (boot_drive_check): New label.
* include/grub/i386/pc/boot.h (GRUB_BOOT_MACHINE_DRIVE_CHECK): New
macro.
* util/i386/pc/grub-setup.c (setup): Added a workaround for BIOSes
which do not pass a boot drive correctly. Copied from GRUB Legacy.
2005-07-17 Yoshinori Okuji <okuji@enbug.org>
* kern/i386/pc/startup.S (gate_a20_try_system_control_port_a):

17
boot/i386/pc/boot.S
View file

@ -1,7 +1,7 @@
/* -*-Asm-*- */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002 Free Software Foundation, Inc.
* Copyright (C) 1999,2000,2001,2002,2005 Free Software Foundation, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@ -108,6 +108,21 @@ after_BPB:
/* general setup */
cli /* we're not safe here! */
/*
* This is a workaround for buggy BIOSes which don't pass boot
* drive correctly. If GRUB is installed into a HDD, check if
* DL is masked correctly. If not, assume that the BIOS passed
* a bogus value and set DL to 0x80, since this is the only
* possible boot drive. If GRUB is installed into a floppy,
* this does nothing (only jump).
*/
boot_drive_check:
jmp 1f
testb $0x80, %dl
jnz 1f
movb $0x80, %dl
1:
/*
* ljmp to the next instruction because some bogus BIOSes
* jump to 07C0:0000 instead of 0000:7C00.

5
include/grub/i386/pc/boot.h
View file

@ -1,6 +1,6 @@
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2002 Free Software Foundation, Inc.
* Copyright (C) 1999,2000,2002,2005 Free Software Foundation, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@ -47,6 +47,9 @@
/* The offset of KERNEL_SEGMENT. */
#define GRUB_BOOT_MACHINE_KERNEL_SEGMENT 0x48
/* The offset of BOOT_DRIVE_CHECK. */
#define GRUB_BOOT_MACHINE_DRIVE_CHECK 0x4b
/* The offset of a magic number used by Windows NT. */
#define GRUB_BOOT_MACHINE_WINDOWS_NT_MAGIC 0x1b8

14
util/i386/pc/grub-setup.c
View file

@ -1,7 +1,7 @@
/* grub-setup.c - make GRUB usable */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2004 Free Software Foundation, Inc.
* Copyright (C) 1999,2000,2001,2002,2003,2004,2005 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
@ -86,6 +86,7 @@ setup (const char *prefix, const char *dir,
grub_device_t root_dev, dest_dev;
grub_uint8_t *boot_drive;
grub_uint32_t *kernel_sector;
grub_uint16_t *boot_drive_check;
struct boot_blocklist *first_block, *block;
grub_int32_t *install_dos_part, *install_bsd_part;
char *install_prefix;
@ -168,10 +169,12 @@ setup (const char *prefix, const char *dir,
boot_img = grub_util_read_image (boot_path);
free (boot_path);
/* Set the addresses of BOOT_DRIVE and KERNEL_SECTOR. */
/* Set the addresses of BOOT_DRIVE, KERNEL_SECTOR and BOOT_DRIVE_CHECK. */
boot_drive = (grub_uint8_t *) (boot_img + GRUB_BOOT_MACHINE_BOOT_DRIVE);
kernel_sector = (grub_uint32_t *) (boot_img
+ GRUB_BOOT_MACHINE_KERNEL_SECTOR);
boot_drive_check = (grub_uint16_t *) (boot_img
+ GRUB_BOOT_MACHINE_DRIVE_CHECK);
core_path = grub_util_get_path (dir, core_file);
core_size = grub_util_get_image_size (core_path);
@ -228,6 +231,13 @@ setup (const char *prefix, const char *dir,
free (tmp_img);
/* If DEST_DRIVE is a hard disk, enable the workaround, which is
for buggy BIOSes which don't pass boot drive correctly. Instead,
they pass 0x00 or 0x01 even when booted from 0x80. */
if (dest_dev->disk->id & 0x80)
/* Replace the jmp (2 bytes) with double nop's. */
*boot_drive_check = 0x9090;
/* If the destination device can have partitions and it is the MBR,
try to embed the core image into after the MBR. */
if (dest_dev->disk->has_partitions && ! dest_dev->disk->partition)