Long Mode 1GByte Pagesize: Page Fault in Bochs!
Posted: Thu May 21, 2009 5:54 am
Hello,
I am already in PMode (Bochs) with no Interrupts working (I implement them in LongMode).
I tried to switch to long mode and want to use 1Gbyte Identitypaging the first GByte.
Therefore I need only one Entry in PML4 and PML3. Both are 4KByte aligned, thats
sure (tested with bochs debugger). The First Entry of the PML4 is (PML3 OR 0x07).
First Entry of PML3 is set to 0x87.
I followed the tutorial in the wiki to enable Long Mode and everytime I enable paging
(last step) I got a page fault. And Bochs say: Physical Address is not available for
linear 0x0000...00. I think I made a mistake with the PML Entries, but don't know wich.
PAE and PGE of EFER is enabled,
also LMA and LME of CR4,
and PG, CD, NW, ET and PE of CR0.
My Code assumes that a binary 64bit file is loaded as first module. Then it is copied
to 0x2000000 (32MByte).
Does anyone see my mistake?
TIA
Sebihepp
I am already in PMode (Bochs) with no Interrupts working (I implement them in LongMode).
I tried to switch to long mode and want to use 1Gbyte Identitypaging the first GByte.
Therefore I need only one Entry in PML4 and PML3. Both are 4KByte aligned, thats
sure (tested with bochs debugger). The First Entry of the PML4 is (PML3 OR 0x07).
First Entry of PML3 is set to 0x87.
I followed the tutorial in the wiki to enable Long Mode and everytime I enable paging
(last step) I got a page fault. And Bochs say: Physical Addr
Code: Select all
linear 0x0000...00. I think I made a mistake with the PML Entries, but don't know wich.
PAE and PGE of EFER is enabled,
also LMA and LME of CR4,
and PG, CD, NW, ET and PE of CR0.
My Code assumes that a binary 64bit file is loaded as first module. Then it is copied
to 0x2000000 (32MByte).
Code: Select all
global start
MULTIBOOT_FLAGS equ 0x00
MULTIBOOT_MAGIC equ 0x1BADB002
MULTIBOOT_CHECKSUM equ -(MULTIBOOT_FLAGS + MULTIBOOT_MAGIC)
START equ 0x1000000
DEST_ADDRESS equ 0x2000000
ADDRESS_PML4 equ 0x00000000
ADDRESS_PML3 equ 0x00000000
ADDRESS_PML2 equ 0x00000000
ADDRESS_PML1 equ 0x00000000
section .text
bits 32
align 4
Multiboot_Header:
dd MULTIBOOT_MAGIC
dd MULTIBOOT_FLAGS
dd MULTIBOOT_CHECKSUM
start:
mov esp, 0x900000
push eax
push ebx
mov esi, ebx
add esi, 0x14
lodsd
test eax, eax
jnz test_long_mode
jmp end
test_long_mode:
mov eax, 0x80000000
CPUID
test eax, eax
jnz .ext_test
jmp end
.ext_test:
mov eax, 0x80000001
CPUID
test edx, 0x20000000
jnz copy_kernel2
jmp end
copy_kernel2:
call copy_kernel
init_paging:
;1 GByte Pagesize
;Identity first Gigabyte
;Set First entry of PML4
mov edi, PML4
mov eax, PML3
or eax, 0x07
stosd
xor eax, eax
stosd
;Set First entry of PML3
mov edi, PML3
mov eax, 0x87
stosd
xor eax, eax
stosd
init_long_mode:
mov eax, 0xA0
mov cr4, eax
mov eax, PML4
mov cr3, eax
mov ecx, 0xC0000080
rdmsr
or eax, 0x100
wrmsr
mov eax, cr0
or eax, 0x80000000
mov cr0, eax
lgdt [GDT]
mov ax, 0x20
mov ds, ax
mov es, ax
mov gs, ax
mov fs, ax
mov ss, ax
mov esp, 0x900000
jmp 0x18:DEST_ADDRESS
end:
hlt
jmp end
copy_kernel:
mov esi, [esi]
lodsd
mov ebx, [esi]
mov edx, ebx
sub edx, eax
mov esi, ebx
mov edi, DEST_ADDRESS
add edi, edx
mov ebx, eax
.loop:
mov eax, [esi]
mov [edi], eax
sub esi, 4
sub edi, 4
cmp esi, ebx
jae .loop
ret
section .data
bits 32
GDT:
dw GDT_END - GDT_NULL - 1
dd GDT_NULL
GDT_NULL:
dd 0x00000000
dd 0x00000000
GDT_CODE32:
dw 0xFFFF
dw 0x0000
db 0x00
db 0x9A
db 0xCF
db 0x00
GDT_DATA32:
dw 0xFFFF
dw 0x0000
db 0x00
db 0x92
db 0xCF
db 0x00
GDT_CODE64:
dw 0xFFFF
dw 0x0000
db 0x00
db 0x9A
db 0x8F
db 0x00
GDT_DATA64:
dw 0xFFFF
dw 0x0000
db 0x00
db 0x92
db 0x8F
db 0x00
GDT_END:
section .page
PML4:
TIMES 512 dq 0x00
PML3:
TIMES 512 dq 0x00
TIA
Sebihepp
