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fix linuxboot.bin and multiboot.bin to not hijack int19

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Currently linuxboot.bin and multiboot.bin option roms override int19
vector to intercept boot process. No sane option rom should do that.
Provide bev entry instead that will be called by BIOS if option rom
is selected for booting.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Gleb Natapov 2011-01-31 15:11:01 +02:00 committed by Aurelien Jarno
parent 31b7c261a2
commit 75b9f69057
3 changed files with 29 additions and 15 deletions
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2
pc-bios/optionrom/linuxboot.S
View File

@ -22,6 +22,8 @@
#include "optionrom.h"
#define BOOT_ROM_PRODUCT "Linux loader"
BOOT_ROM_START
run_linuxboot:

2
pc-bios/optionrom/multiboot.S
View File

@ -20,6 +20,8 @@
#include "optionrom.h"
#define BOOT_ROM_PRODUCT "multiboot loader"
#define MULTIBOOT_MAGIC 0x2badb002
#define GS_PROT_JUMP 0

40
pc-bios/optionrom/optionrom.h
View File

@ -97,22 +97,28 @@
#define BOOT_ROM_START \
OPTION_ROM_START \
push %eax; \
push %ds; \
\
/* setup ds so we can access the IVT */ \
xor %ax, %ax; \
mov %ax, %ds; \
\
/* install our int 19 handler */ \
movw $int19_handler, (0x19*4); \
mov %cs, (0x19*4+2); \
\
pop %ds; \
pop %eax; \
lret; \
\
int19_handler:; \
.org 0x18; \
.short 0; \
.short _pnph; \
_pnph: \
.ascii "$PnP"; \
.byte 0x01; \
.byte ( _pnph_len / 16 ); \
.short 0x0000; \
.byte 0x00; \
.byte 0x00; \
.long 0x00000000; \
.short _manufacturer; \
.short _product; \
.long 0x00000000; \
.short 0x0000; \
.short 0x0000; \
.short _bev; \
.short 0x0000; \
.short 0x0000; \
.equ _pnph_len, . - _pnph; \
_bev:; \
/* DS = CS */ \
movw %cs, %ax; \
movw %ax, %ds;
@ -122,5 +128,9 @@
_end:
#define BOOT_ROM_END \
_manufacturer:; \
.asciz "QEMU"; \
_product:; \
.asciz BOOT_ROM_PRODUCT; \
OPTION_ROM_END