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* grub-core/boot/i386/pc/startup_raw.S (grub_gate_a20): Remove

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argument. We don't disable Gate A20 in this code.
This commit is contained in:
Vladimir Serbinenko 2013-10-25 11:03:39 +02:00
parent b46684ae53
commit ad2dc00309
2 changed files with 18 additions and 30 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
2013-10-25 Vladimir Serbinenko <phcoder@gmail.com>
* grub-core/boot/i386/pc/startup_raw.S (grub_gate_a20): Remove
argument. We don't disable Gate A20 in this code.
2013-10-25 Vladimir Serbinenko <phcoder@gmail.com>
* grub-core/boot/i386/qemu/boot.S: Ensure that A20 is enabled.

43
grub-core/boot/i386/pc/startup_raw.S
View file

@ -100,7 +100,6 @@ LOCAL (codestart):
/* The ".code32" directive takes GAS out of 16-bit mode. */
.code32
incl %eax
cld
call grub_gate_a20
@ -124,7 +123,7 @@ LOCAL (codestart):
.text
/*
* grub_gate_a20(int on)
* grub_gate_a20(void)
*
* Gate address-line 20 for high memory.
*
@ -134,12 +133,10 @@ LOCAL (codestart):
*/
grub_gate_a20:
movl %eax, %edx
gate_a20_test_current_state:
/* first of all, test if already in a good state */
call gate_a20_check_state
cmpb %al, %dl
testb %al, %al
jnz gate_a20_try_bios
ret
@ -149,18 +146,15 @@ gate_a20_try_bios:
call prot_to_real
.code16
movw $0x2400, %ax
testb %dl, %dl
jz 1f
incw %ax
1: int $0x15
movw $0x2401, %ax
int $0x15
DATA32 call real_to_prot
.code32
popl %ebp
call gate_a20_check_state
cmpb %al, %dl
testb %al, %al
jnz gate_a20_try_system_control_port_a
ret
@ -172,20 +166,13 @@ gate_a20_try_system_control_port_a:
/* fourth, try the system control port A */
inb $0x92
andb $(~0x03), %al
testb %dl, %dl
jz 6f
orb $0x02, %al
6: outb $0x92
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. */
testb %dl, %dl
jz 7f
call gate_a20_check_state
cmpb %al, %dl
testb %al, %al
jnz gate_a20_try_keyboard_controller
7: ret
ret
gate_a20_flush_keyboard_buffer:
inb $0x64
@ -211,11 +198,8 @@ gate_a20_try_keyboard_controller:
andb $0x02, %al
jnz 4b
movb $0xdd, %al
testb %dl, %dl
jz 5f
orb $0x02, %al
5: outb $0x60
movb $0xdf, %al
outb $0x60
call gate_a20_flush_keyboard_buffer
/* output a dummy command (USB keyboard hack) */
@ -224,7 +208,7 @@ gate_a20_try_keyboard_controller:
call gate_a20_flush_keyboard_buffer
call gate_a20_check_state
cmpb %al, %dl
testb %al, %al
/* everything failed, so restart from the beginning */
jnz gate_a20_try_bios
ret
@ -234,7 +218,7 @@ gate_a20_check_state:
movl $100, %ecx
1:
call 3f
cmpb %al, %dl
testb %al, %al
jz 2f
loop 1b
2:
@ -263,9 +247,8 @@ gate_a20_check_state:
pushl %ebx
addl $0x100000, %ebx
movb (%ebx), %ch
/* this result is 1 if A20 is on or 0 if it is off */
/* this result is 0 if A20 is on or 1 if it is off */
subb %ch, %al
xorb $1, %al
/* restore the original */
popl %ebx
movb %cl, (%ebx)