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Move chainloader_real_boot out of the kernel

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This commit is contained in:
Vladimir 'phcoder' Serbinenko 2011-10-21 00:16:59 +02:00
parent 766f7d0809
commit db1326f5fb
11 changed files with 148 additions and 69 deletions
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85
grub-core/lib/i386/relocator16.S
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@ -93,6 +93,85 @@ LOCAL(segment):
.word 0
LOCAL(cont3):
/* movw imm16, %ax. */
.byte 0xb8
VARIABLE(grub_relocator16_keep_a20_enabled)
.word 0
test %ax, %ax
jnz LOCAL(gate_a20_done)
/* first of all, test if already in a good state */
call LOCAL(gate_a20_check_state)
testb %al, %al
jz LOCAL(gate_a20_done)
/* second, try a BIOS call */
movw $0x2400, %ax
int $0x15
call LOCAL(gate_a20_check_state)
testb %al, %al
jz LOCAL(gate_a20_done)
/*
* In macbook, the keyboard test would hang the machine, so we move
* this forward.
*/
/* fourth, try the system control port A */
inb $0x92
andb $(~0x03), %al
outb $0x92
/* When turning off Gate A20, do not check the state strictly,
because a failure is not fatal usually, and Gate A20 is always
on some modern machines. */
jmp LOCAL(gate_a20_done)
LOCAL(gate_a20_check_state):
/* iterate the checking for a while */
movw $100, %cx
1:
call 3f
testb %al, %al
jz 2f
loop 1b
2:
ret
3:
xorw %ax, %ax
movw %ax, %ds
decw %ax
movw %ax, %es
xorw %ax, %ax
movw $0x8000, %ax
/* compare the byte at ADDR with that at 0x100000 + ADDR */
movw %ax, %si
addw $0x10, %ax
movw %ax, %di
/* save the original byte in DL */
movb %ds:(%si), %dl
movb %es:(%di), %al
/* try to set one less value at ADDR */
movb %al, %dh
decb %dh
movb %dh, %ds:(%si)
/* serialize */
outb %al, $0x80
outb %al, $0x80
/* obtain the value at 0x100000 + ADDR in CH */
movb %es:(%di), %dh
/* this result is 1 if A20 is on or 0 if it is off */
subb %dh, %al
xorb $1, %al
/* restore the original */
movb %dl, %es:(%di)
ret
LOCAL(gate_a20_done):
/* we are in real mode now
* set up the real mode segment registers : DS, SS, ES
*/
@ -132,6 +211,12 @@ VARIABLE(grub_relocator16_sp)
.word 0
movzwl %ax, %esp
/* movw imm32, %eax. */
.byte 0x66, 0xb8
VARIABLE(grub_relocator16_esi)
.long 0
movl %eax, %esi
/* movw imm32, %edx. */
.byte 0x66, 0xba
VARIABLE(grub_relocator16_edx)