1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
|
[GLOBAL read_eip]
read_eip:
pop eax
jmp eax
[GLOBAL idle_task]
idle_task:
sti
hlt
jmp idle_task
[GLOBAL atomic_exchange]
atomic_exchange:
mov ecx, [esp+4] ; Get lock address
mov eax, [esp+8] ; Get new value
xchg eax, [ecx] ; Old value goes in eax
ret
[GLOBAL copy_page_physical]
copy_page_physical:
push ebx ; According to __cdecl, we must preserve the contents of EBX.
pushf ; push EFLAGS, so we can pop it and reenable interrupts
; later, if they were enabled anyway.
cli ; Disable interrupts, so we aren't interrupted.
; Load these in BEFORE we disable paging!
mov ebx, [esp+12] ; Source address
mov ecx, [esp+16] ; Destination address
mov edx, cr0 ; Get the control register...
and edx, 0x7fffffff ; and...
mov cr0, edx ; Disable paging.
mov edx, 1024 ; 1024*4bytes = 4096 bytes to copy
.loop:
mov eax, [ebx] ; Get the word at the source address
mov [ecx], eax ; Store it at the dest address
add ebx, 4 ; Source address += sizeof(word)
add ecx, 4 ; Dest address += sizeof(word)
dec edx ; One less word to do
jnz .loop
mov edx, cr0 ; Get the control register again
or edx, 0x80000000 ; and...
mov cr0, edx ; Enable paging.
popf ; Pop EFLAGS back.
pop ebx ; Get the original value of EBX back.
ret
|
