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3faa92d094
os-k/boot/loader.asm
Julian Barathieu 3faa92d094 Big reorganization & stuff
2019-01-14 14:31:49 +01:00

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;=----------------------------------------------------------------------------=;
; GNU GPL OS/K ;
; ;
; Authors: spectral` ;
; NeoX ;
; ;
; Desc: Kernel (second stage) Loader for OS/K ;
; (x86_64 architecture only) ;
;=----------------------------------------------------------------------------=;
;;VIDEO
%define TRAM 0x0B8000 ; [T]ext[RAM]
%define VRAM 0x0A0000 ; [V]ideo[RAM]
;; BPB
%define OEMName bp+0x03 ; Disk label
%define bytesPerSector bp+0x0b ; Bytes per sector
%define sectorsPerCluster bp+0x0d ; Sectors per cluster
%define reservedSectors bp+0x0e ; Reserved sectors
%define fats bp+0x10 ; Number of fats
%define rootDirEntries bp+0x11 ; Number of entries in root dir
%define sectors bp+0x13 ; Logical sectors
%define mediaType bp+0x15 ; Media descriptor byte
%define fatSectors bp+0x16 ; Sectors per FAT
%define sectorsPerTrack bp+0x18 ; Sectors per track
%define heads bp+0x1a ; Number of sides/heads
%define hiddenSectors bp+0x1c ; Hidden sectors
%define hugeSectors bp+0x20 ; LBA sectors
%define biosBootdrvNum bp+0x24 ; Bootdrv number
%define reserved bp+0x25 ; This is not used
%define bootSignature bp+0x26 ; Bootdrv signature
%define volumeId bp+0x27 ; Volume ID
%define volumeLabel bp+0x2b ; Volume Label
%define fatTypeLabel bp+0x36 ; File system type
[BITS 16]
[ORG 0x1000]
mov ax, cs ; correcting cs after the horrible far jump
mov ds, ax ; hm... And ds too
mov es, ax ; And es because it is jealous
mov [Bootdrv], dl
jmp 0x0000:main
;; DATA
Bootdrv db 0
VGA_HEIGHT dq 0
VIDEO_MODE dw 0
;; GDT WITH DOC
GDT64:
NULL_SELECTOR: ;; null selector within 64 bits
dw GDT_LENGTH ; limit of GDT
dw GDT64 ; linear address of GDT
dd 0x0 ;
CODE_SELECTOR: ;; 32-bit code selector (ring 0)
dw 0x0FFFF ; Segment Limit
db 0x0, 0x0, 0x0 ; Base Address
db 10011010b ; |7|6|5|4|3|2|1|0|
; | | | | | | | `----- 1 when segment used.
; | | | | | | `------ 1 when writable.
; | | | | | `------- 1 if "conformant". Don't know what is it... spectral ? xD
; | | | | `-------- 1 always
; | | | `--------- 1 for segment descriptor, 0 for system descriptor
; | | `---------- DPL !!! 0 for ring 0
; | `----------- DPL (2/2)
; `------------ 1 if in physical memory, 0 if page fault
db 11001111b ; |7|6|5|4|3|2|1|0|
; | | | | | | | `----- Limit 16
; | | | | | | `------ Limit 17
; | | | | | `------- Limit 18
; | | | | `-------- Limit 19
; | | | `--------- available for use
; | | `---------- 0 always
; | `----------- size of data. 1 for 32bits
; `------------ 0 if limit is in Bytes, 1 if it's in pages (4ko)
db 0x0 ; Base Address
DATA_SELECTOR: ;; flat data selector (ring 0)
dw 0x0FFFF ; Segment Limit
db 0x0, 0x0, 0x0 ; Base Address
db 10010010b ; |7|6|5|4|3|2|1|0|
; | | | | | | | `----- 1 when segment used.
; | | | | | | `------ 1 when writable.
; | | | | | `------- expansion direction. 1 for a LIFO
; | | | | `-------- 1 always
; | | | `--------- 1 for segment descriptor, 0 for system descriptor
; | | `---------- DPL !!! 0 for ring 0
; | `----------- DPL (2/2)
; `------------ 1 if in physical memory, 0 if page fault
db 10001111b ; |7|6|5|4|3|2|1|0|
; | | | | | | | `----- Limit 16
; | | | | | | `------ Limit 17
; | | | | | `------- Limit 18
; | | | | `-------- Limit 19
; | | | `--------- available for use
; | | `---------- 0 always
; | `----------- size of data. 1 for 32bits
; `------------ 0 if limit is in Bytes, 1 if it's in pages (4ko)
db 0x0 ; Base Address
LONG_SELECTOR: ;; 64-bit code selector (ring 0)
dw 0x0FFFF ; Segment Limit
db 0x0, 0x0, 0x0 ; Base Address
db 10011010b ; |7|6|5|4|3|2|1|0|
; | | | | | | | `----- 1 when segment used.
; | | | | | | `------ 1 when writable.
; | | | | | `------- 1 if "conformant". Don't know what is it... spectral ? xD
; | | | | `-------- 1 always
; | | | `--------- 1 for segment descriptor, 0 for system descriptor
; | | `---------- DPL !!! 0 for ring 0
; | `----------- DPL (2/2)
; `------------ 1 if in physical memory, 0 if page fault
db 10101111b ; |7|6|5|4|3|2|1|0|
; | | | | | | | `----- Limit 16
; | | | | | | `------ Limit 17
; | | | | | `------- Limit 18
; | | | | `-------- Limit 19
; | | | `--------- available for use
; | | `---------- 0 always
; | `----------- size of data. 1 for 32bits
; `------------ 0 if limit is in Bytes, 1 if it's in pages (4ko)
db 0x0 ; Base Address
GDT_LENGTH:
%include "boot/loader16.inc"
main:
;; compatibility check
mov si, Init
call PrintB
pop si
call Is64bits
jc ErrorNo64
push si
mov si, Pass
call PrintB
;; Enabling A20
mov si, EnA20
call PrintB
pop si
in al, 0x92
or al, 2
out 0x92, al
push si
mov si, Pass
call PrintB
;; DISABLING CURSOR BLINKING AND GETTING INFOS
call get_dimensions
call disable_cursor
;;GO GDT64
cli ; disable interrupts
lgdt [GDT64]
;; ACTIVATE PROTECTED MODE
mov eax, cr0
or al, 1b ; PE = 1
mov cr0, eax
;; DISABLE PAGING
mov eax, cr0
and eax, 0x7FFFFFFF ; PG = 0
; |0|111111111111111111111111111111
; |
; `------ Paging bit
mov cr0, eax
push dword [VIDEO_MODE]
push dword [VGA_HEIGHT]
jmp (CODE_SELECTOR-GDT64):main32
[BITS 32]
VIDEO_MODE32 dw 0
VGA_HEIGHT32 dw 0
main32:
pop dword [VGA_HEIGHT32]
pop dword [VIDEO_MODE32]
;; INITIALIZE PROTECTED MODE SEGMENT REGISTERS
mov ax, DATA_SELECTOR-GDT64
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ss, ax
;; ACTIVATE PHYSICAL ADRESS EXTENSION
mov eax, cr4
or eax, 100000b ; PAE = 1 = 4 Mo / page. 0 = 4 Ko
mov cr4, eax
;;cleanup
mov edi, 0x70000
mov ecx, 0x10000
xor eax, eax
rep stosd
;;formatting
mov dword [0x70000], 0x71000 + 7 ; first PDP table
mov dword [0x71000], 0x72000 + 7 ; first page directory
mov dword [0x72000], 0x73000 + 7 ; first page table
mov edi, 0x73000 ; address of first page table
mov eax, 7
mov ecx, 256 ; number of pages to map (1 MB)
.make_page_entries:
stosd
add edi, 4
add eax, 0x1000
loop .make_page_entries
;; pointing pml4
mov eax, 0x70000 ; Bass address of PML4
mov cr3, eax ; load page-map level-4 base
;; ACTIVATE LONG MODE
mov ecx, 0xC0000080 ; address of MSR
rdmsr ; read MSR
or eax, 100000000b ; LME = 1. (Long Mode Enable)
wrmsr ; write MSR
;; ACTIVATE PAGING
mov eax, cr0
or eax, 0x80000000 ; make bit 31 (PG = Paging) to 1 :
; |1|000000000000000000000000000000
; |
; `------ Paging bit
mov cr0, eax
push dword 0
push dword [VIDEO_MODE]
push dword 0
push dword [VGA_HEIGHT]
jmp (LONG_SELECTOR-GDT64):main64
[BITS 64]
%include "boot/loader64.inc"
;; DATA
txt db 0x09, " Switching to Long Mode... ", 0
Init db "Booting OS/K !", 0x0D, 0x0A, 0x0D, 0x0A, 0x09, " Checking CPUID...",0
Reinit db "Booting OS/K !", 0x0D, 0x0A, 0x0D, 0x0A, 0
CPUIDD db 0x09, " Checking CPUID...", 0
EnA20 db 0x09, " Enabling A20 line...", 0
NoLongMode db 0x0A, 0x0D, "ERROR : Your computer is not designed for x64 OS", 0
Pass db " OK", 0x0A, 0x0D, 0
NextTRAM dq 0x0B8000 ; Last position of cursor
VIDEO_MODE64 dq 0
VGA_HEIGHT64 dq 0
VGA_X dq 0x0
msg db "The system is now in x64 mode. Is this not beautiful ?", 0x0A, 0x0D, 0
main64:
pop qword [VGA_HEIGHT64]
pop qword [VIDEO_MODE64]
;; INITIALIZE STACK
mov rsp, 0x9F000
call clear
;; Printing
mov bl, 0x0B
mov esi, Reinit
call write
mov bl, 0x0F
mov esi, CPUIDD
call write
mov bl, 0x0A
mov esi, Pass
call write
mov bl, 0x0F
mov esi, EnA20
call write
mov bl, 0x0A
mov esi, Pass
call write
mov bl, 0x0F
mov esi, txt
call write
mov bl, 0x0A
mov esi, Pass
call write
mov bl, 0x0D
mov esi, msg
call write
jmp Die
[BITS 16]
ErrorNo64:
mov si, NoLongMode
call PrintB
Die:
cli
hlt ; die nooooow
jmp 0xF000:0xFFF0
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