coreboot-kgpe-d16/util/ADLO/loader.s

462 lines
8.8 KiB
ArmAsm

;*****************************************************
; $Id: loader.s,v 1.1 2002/11/25 02:07:53 rminnich Exp $
;*****************************************************
USE32
; code it is loaded into memory at 0x7C00
;*****************************************************
nop
nop
;*****************************************************
; A) setup GDT, so that we do not depend on program
; that loaded us for GDT.
; Ex: coreboot and EtherBOOT use different GDT's.
;-----------------------------------------------------
; 0)
cli
;-----------------------------------------------------
; I)
lgdt [0x7C00+protected_gdt]
;-----------------------------------------------------
; II) setup CS
jmp 0x08:0x7C00+newpgdt
newpgdt: nop
;-----------------------------------------------------
; III) setup all other segments
mov ax, #0x10
mov ss, ax
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
;-----------------------------------------------------
; IV)
; not now
;sti
;*****************************************************
nop
nop
;*****************************************************
; B) shadow - ON (enable/read/write)
mov eax, #0x80000070
mov dx, #0x0cf8
out dx, eax
mov eax, #0xFFFFFFFF
mov dx, #0x0cfc
out dx, eax
;*****************************************************
nop
nop
;*****************************************************
; C) copy -- boch bios
; counter - 64kb.
mov ecx, #0x10000
; source - 0x8000 ( 0x7C00+0x400 = 0x8000 )
mov ax, #0x10 ; src-segment - 2nd entry in GDT
mov ds, ax
mov eax, #0x8000 ; src-offset - 0x8000
mov esi, eax
; destination - 0xE0000
mov ax, #0x10 ; dst-segment - 2nd entry in GDT
mov es, ax
mov eax, #0xF0000 ; dst-offset - 0xF0000
mov edi, eax
; clear direction flag
cld
; the copy
rep
movsb
;*****************************************************
nop
nop
;*****************************************************
; X) copy -- coreboot table into safe place.
;; TODO.
;; Q1 : what is the size of table.
;; Q2 : where to copy?
;*****************************************************
nop
nop
;*****************************************************
; E) shadow - OFF (write)
mov eax, #0x80000070
mov dx, #0x0cf8
out dx, eax
;mov eax, #0xFFFFFFFF
mov eax, #0x0000FFFF
mov dx, #0x0cfc
out dx, eax
;*****************************************************
nop
nop
;*****************************************************
; F) do a little prep work.
;-----------------------------------------------------
; I) disable cache
; if you disable cache, GRUB's GFX mode will be VERY slow.
; so DO NOT DISABLE
;mov eax, cr0
;or eax, #0x60000000
;wbinvd
;mov cr0, eax
;wbinvd
;-----------------------------------------------------
; II) disable MTRR
; clear the "E" (0x800) and "FE" (0x400) flags in
; IA32_MTRRdefType register (0x2FF)
;-----------------------
;mov ECX,#0x2FF
; select either of the two below
; depending on if your compiler suports
; {RD,WR}MSR or not
;rdmsr
; .byte 0x0F, 0x32
;xor edx, edx
; xor eax, eax
;and eax, #0xFFFFF3FF
; select either of the two below
; depending on if your compiler suports
; {RD,WR}MSR or not
;wrmsr
; .byte 0x0F, 0x30
;-----------------------
;; This is what PC BIOS is setting. -- P6STMT.
; add VIDEO BIOS cacheable!!!!
;-----------------------
; Fixed Range C0--C8
;mov ECX,#0x268
;mov EDX,#0x05050505
;mov EAX,#0x05050505
;wrmsr
;-----------------------
; Fixed Range C8--CF
;mov ECX,#0x269
;mov EDX,#0x0
;mov EAX,#0x05050505
;wrmsr
;-----------------------
;-----------------------------------------------------
; III) tell BOCHS' BIOS we want to boot from hdd.
; 0x00 - floppy
; 0x02 - hdd
; In future there will be 'fd failover'option in bochs.
mov al, #0x3d ;; cmos_reg
out 0x70, al
mov al, #0x02 ;; val (hdd)
out 0x71, al
;-----------------------------------------------------
; IV) tell BOCHS' BIOS length of our mem block @ 1mb.
; This is for Int 15 / EAX=E820
; 119mb = 0x77 00 00 00
; (this is for 128mb of ram)
; (FIXME: this value is currently hard coded)
; (it should be being passed from coreboot )
; for WinFast 6300
; 07 70 = 0770
; 06 80 = 0770 - 00F0 << ALT (for unpatched bochs)
; for P6STMT - 10kb less ram
; 077F - 10 = 07 6F
; 07 6F - 00 F0 = 06 7F
mov al, #0x35 ;; cmos_reg
out 0x70, al
mov al, #0x06 ;; val
out 0x71, al
mov al, #0x34 ;; cmos_reg
out 0x70, al
mov al, #0x7F ;; val
out 0x71, al
mov al, #0x31 ;; cmos_reg
out 0x70, al
mov al, #0x00 ;; val
out 0x71, al
mov al, #0x30 ;; cmos_reg
out 0x70, al
mov al, #0x00 ;; val
out 0x71, al
;-----------------------------------------------------
; V) tell BOCHS' BIOS we want to have LBA translation.
; 0x00 - NONE
; 0x01 - LBA <<<<
; 0x02 - LARGE
; 0x03 - R-CHS
; In future there will be 'fd failover'option in bochs.
mov al, #0x39 ;; cmos_reg
out 0x70, al
mov al, #0x01 ;; val (LBA)
out 0x71, al
;*****************************************************
nop
nop
;*****************************************************
; G) the switch -- protected to real mode
; IASDM, Vol 3
; (8-14) 8.8.2 Switching Back to Real-Address Mode
;=====================================================
; 1) disable interrupts
cli
;=====================================================
nop
;=====================================================
; 2) paging
;not enabled, so not applicable.
;=====================================================
; 3) setup CS segment limit (64kb)
; I)
lgdt [0x7C00+new_gdt]
;-----------------------------------------------------
; II)
jmp 0x08:0x7C00+new64lim
new64lim: nop
;=====================================================
nop
;=====================================================
; 4) setup all other segments
mov ax, #0x10
mov ss, ax
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
;=====================================================
nop
;=====================================================
; 5) LIDT
; I)
; set up Real Mode IDT table (0...3FF)
; for BOCH's BIOS the address 0xF000:0xFF53
; cantains value 0xCF which is IRET opcode.
; counter
mov cx, #0xFF ;1024 bytes(255 interrupts)(4*255=0x3FF)
; destination - 0x00000 = ES:EDI
mov ax, #0x10 ; dst-segment - 2nd entry in GDT
mov es, ax
mov eax, #0x00000 ; dst-offset - 0x00000
mov edi, eax
; data to store -- 0xF000:FF53
mov eax, #0xF000FF53
; clear direction flag
cld
; the store
rep
stosd
;-----------------------------------------------------
; II)
; load interrupt descriptor table
lidt [0x7C00+new_idt]
;=====================================================
nop
nop
;=====================================================
; 6) clear the PE flag in CR0 register.
; I)
; switch to 16 bit segments
mov ax, #0x20
mov ss, ax
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
;-----------------------------------------------------
; II)
; switch to 16 bit CS
jmp 0x018:0x7C00+new16bit
USE16
new16bit: nop
;-----------------------------------------------------
; III)
; the switch
;xor eax, eax
mov eax, cr0
and eax, #0xFFFFFFFE
mov cr0, eax ;switch to RM
;=====================================================
nop
nop
;=====================================================
; 7) far jump -- (to real mode address)
jmp 0x0:0x7C00+realcs
realcs: nop
;=====================================================
; 8) set all segment registers to 0's
mov ax, #0x0
mov ss, ax
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
;=====================================================
; 9) re-enable interrupts
sti
;*****************************************************
nop
nop
;*****************************************************
; G) jump to BIOS.
jmp 0xFFFF:0x0000
;jmp 0xF000:0xFFF0
;*****************************************************
;*****************************************************
nop
nop
nop
nop
;*****************************************************
;*****************************************************
USE32
new_idt:
dw 0x03ff ;; limit 15:00
dw 0x0000 ;; base 15:00
dw 0x0000 ;; base 23:16
new_gdt:
dw 0x0028 ;; limit 15:00
dw 0x7C00+new_gdt_table ;; base 15:00
dw 0x0000 ;; base 23:16
protected_gdt:
dw 0x0018 ;; limit 15:00
dw 0x7C00+pmode_gdt_table ;; base 15:00
dw 0x0000 ;; base 23:16
;-----------------------------------------------------
new_gdt_table:
;// 1 2 3 4
;//0
dd 0x00000000
dd 0x00000000
;//8
dd 0x0000ffff
dd 0x00409E00
;//10
dd 0x0000ffff
dd 0x00409200
;//18
dd 0x0000ffff
dd 0x00009a00
;//20
dd 0x0000ffff
dd 0x00009200
;-------------------------
pmode_gdt_table:
;// 1 2 3 4
;//0
dd 0x00000000
dd 0x00000000
;//8
dd 0x0000ffff
dd 0x00CF9E00
;//10
dd 0x0000ffff
dd 0x00CF9200
;*****************************************************
;*****************************************************
; the file size must be 1024 bytes.
.org 0x400-1
; dd 0xdeadbeef
db 0x0
;*****************************************************