vbatts/grub
1
0
Fork 0
Code Issues Pull requests Releases Wiki Activity

Move chainloader_real_boot out of the kernel

Browse source
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
Download patch file Download diff file Expand all files Collapse all files

1
grub-core/lib/i386/reboot.c
View file

@ -49,6 +49,7 @@ grub_reboot (void)
state.sp = 0;
state.cs = segment;
state.ip = 0;
state.a20 = 0;
grub_stop_floppy ();

9
grub-core/lib/i386/relocator.c
View file

@ -51,6 +51,9 @@ extern grub_uint16_t grub_relocator16_ss;
extern grub_uint16_t grub_relocator16_sp;
extern grub_uint32_t grub_relocator16_edx;
extern grub_uint32_t grub_relocator16_ebx;
extern grub_uint32_t grub_relocator16_esi;
extern grub_uint16_t grub_relocator16_keep_a20_enabled;
extern grub_uint8_t grub_relocator32_start;
extern grub_uint8_t grub_relocator32_end;
@ -195,7 +198,8 @@ grub_relocator16_boot (struct grub_relocator *rel,
void *relst;
grub_relocator_chunk_t ch;
err = grub_relocator_alloc_chunk_align (rel, &ch, 0,
/* Put it higher than the byte it checks for A20 check. */
err = grub_relocator_alloc_chunk_align (rel, &ch, 0x8010,
0xa0000 - RELOCATOR_SIZEOF (16),
RELOCATOR_SIZEOF (16), 16,
GRUB_RELOCATOR_PREFERENCE_NONE);
@ -215,6 +219,9 @@ grub_relocator16_boot (struct grub_relocator *rel,
grub_relocator16_ebx = state.ebx;
grub_relocator16_edx = state.edx;
grub_relocator16_esi = state.esi;
grub_relocator16_keep_a20_enabled = state.a20;
grub_memmove (get_virtual_current_address (ch), &grub_relocator16_start,
RELOCATOR_SIZEOF (16));

85
grub-core/lib/i386/relocator16.S
View file

@ -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)