added copyright tags

[palacios.git] / palacios / src / geekos / setup.asm

; -*- fundamental -*-
; GeekOS setup code
; Copyright (c) 2001,2004 David H. Hovemeyer <daveho@cs.umd.edu>
; Copyright (c) 2008 Jack Lange <jarusl@cs.northwestern.edu>
; $Revision: 1.8 $

; This is free software.  You are permitted to use,
; redistribute, and modify it as specified in the file "COPYING".

; A lot of this code is adapted from Kernel Toolkit 0.2
; and Linux version 2.2.x, so the following copyrights apply:

; Copyright (C) 1991, 1992 Linus Torvalds
; modified by Drew Eckhardt
; modified by Bruce Evans (bde)
; adapted for Kernel Toolkit by Luigi Sgro

%define __BIG_KERNEL__

%include "defs.asm"

[BITS 16]
[ORG 0x0]

start:
                db      0xEB
                db      46 ;trampoline

; This is the setup header, and it must start at %cs:2 (old 0x9020:2)

                db      'H'             ; header signature
                db      'd'
                db      'r'
                db      'S'
                dw      0x0203          ; header version number (>= 0x0105)
                                        ; or else old loadlin-1.5 will fail)
realmode_swtch: dw      0, 0            ; default_switch, SETUPSEG
start_sys_seg:  dw      SYSSEG
                dw      kernel_version  ; pointing to kernel version string
                                        ; above section of header is compatible
                                        ; with loadlin-1.5 (header v1.5). Don't
                                        ; change it.

type_of_loader: db      0               ; = 0, old one (LILO, Loadlin,
                                        ;      Bootlin, SYSLX, bootsect...)
                                        ; See Documentation/i386/boot.txt for
                                        ; assigned ids
        
; flags, unused bits must be zero (RFU) bit within loadflags
loadflags:  db 1
;LOADED_HIGH    equ 1                   ; If set, the kernel is loaded high
;CAN_USE_HEAP   equ 0x80                        ; If set, the loader also has set
                                        ; heap_end_ptr to tell how much
                                        ; space behind setup.S can be used for
                                        ; heap purposes.
                                        ; Only the loader knows what is free
;%ifndef __BIG_KERNEL__
;               db      1
;%else
;               db      1
;%endif

setup_move_size: dw  0x8000             ; size to move, when setup is not
                                        ; loaded at 0x90000. We will move setup 
                                        ; to 0x90000 then just before jumping
                                        ; into the kernel. However, only the
                                        ; loader knows how much data behind
                                        ; us also needs to be loaded.

code32_start: dd 0x100000                               ; here loaders can put a different
                                        ; start address for 32-bit code.
;%ifndef __BIG_KERNEL__
;               dd      0x100000        ;   0x1000 = default for zImage
;%else
;               dd      0x100000        ; 0x100000 = default for big kernel
;%endif

ramdisk_image:  dd      0               ; address of loaded ramdisk image
                                        ; Here the loader puts the 32-bit
                                        ; address where it loaded the image.
                                        ; This only will be read by the kernel.

ramdisk_size:   dd      0               ; its size in bytes

bootsect_kludge:
                dd      0               ; obsolete

heap_end_ptr:   dw      modelist+1024   ; (Header version 0x0201 or later)
                                        ; space from here (exclusive) down to
                                        ; end of setup code can be used by setup
                                        ; for local heap purposes.

pad1:           dw      0
cmd_line_ptr:   dd      0               ; (Header version 0x0202 or later)
                                        ; If nonzero, a 32-bit pointer
                                        ; to the kernel command line.
                                        ; The command line should be
                                        ; located between the start of
                                        ; setup and the end of low
                                        ; memory (0xa0000), or it may
                                        ; get overwritten before it
                                        ; gets read.  If this field is
                                        ; used, there is no longer
                                        ; anything magical about the
                                        ; 0x90000 segment; the setup
                                        ; can be located anywhere in
                                        ; low memory 0x10000 or higher.

ramdisk_max:      dd 0xffffffff
;kernel_alignment:  dd 0x200000          ; physical addr alignment required for
                                        ; protected mode relocatable kernel
;%ifdef CONFIG_RELOCATABLE
;relocatable_kernel:    db 1
;%else
;relocatable_kernel:    db 0
;%endif
;pad2:                  db 0
;pad3:                  dw 0

;cmdline_size:   dd   COMMAND_LINE_SIZE-1     ;length of the command line,
                                              ;added with boot protocol
                                              ;version 2.06

trampoline:     call    start_setup
;               ALIGN 16
space: 
       %rep  1024
             db 0
       %endrep                          ; The offset at this point is 0x240     
                                        
; End of setup header ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


start_setup:

        ; Redefine the data segment so we can access variables
        ; declared in this file.
        mov     ax, SETUPSEG
        mov     ds, ax

        ; Use int 15h to find out size of extended memory in KB.
        ; Extended memory is the memory above 1MB.  So by
        ; adding 1MB to this amount, we get the total amount
        ; of system memory.  We can only detect 64MB this way,
        ; but that's OK for now.
        ;mov    ah, 0x88
        ;int    0x15
        ;add    ax, 1024        ; 1024 KB == 1 MB
        mov     ax, 0xe801
        int     0x15
        add     ax, 1024        ; 1024 KB == 1 MB
        mov     [mem_size_kbytes], ax
        mov     [mem_size_eblocks], bx

        ; Kill the floppy motor.
        call    Kill_Motor

        ; Block interrupts, since we can't meaningfully handle them yet
        ; and we no longer need BIOS services.
        cli

        ; Set up IDT and GDT registers
        lidt    [IDT_Pointer]
        lgdt    [GDT_Pointer]

        ; Initialize the interrupt controllers, and enable the
        ; A20 address line
        call    Init_PIC
        call    Enable_A20

        ; Switch to protected mode!
        mov     ax, 0x01
        lmsw    ax


        ; Jump to 32 bit code.
        jmp     dword KERNEL_CS:(SETUPSEG << 4) + setup_32

[BITS 32]
setup_32:

        ; set up data segment registers
        mov     ax, KERNEL_DS
        mov     ds, ax
        mov     es, ax
        mov     fs, ax
        mov     gs, ax
        mov     ss, ax

        ; Create the stack for the initial kernel thread.
        mov     esp, KERN_STACK + 4096

        ; Build Boot_Info struct on stack.
        ; Note that we push the fields on in reverse order,
        ; since the stack grows downwards.

        ;Zheng 08/02/2008
        xor eax, eax
        mov eax, [(SETUPSEG<<4)+ramdisk_size]
        push eax

        xor eax, eax
        mov eax, [(SETUPSEG<<4)+ramdisk_image]
        push eax        

        xor     eax, eax
        mov     ax, [(SETUPSEG<<4)+mem_size_kbytes]
        xor     ebx, ebx
        mov     bx, [(SETUPSEG<<4)+mem_size_eblocks]
        shl     ebx, 6
        add     eax, ebx
        push    eax             ; memSizeKB
        
        mov     eax, VMM_SIZE
        shl     eax, 9          ; Multiply the vmm size by 512 to get byte size
        push    ebx             ; size of the VMM

        push    dword 8         ; bootInfoSize

        ; Pass pointer to Boot_Info struct as argument to kernel
        ; entry point.
        push    esp

        ; Push return address to make this look like a call
        ; XXX - untested
        push    dword (SETUPSEG<<4)+.returnAddr


        ; Far jump into kernel
        jmp     KERNEL_CS:ENTRY_POINT

.returnAddr:
        ; We shouldn't return here.
.here:  jmp .here




[BITS 16]

; Kill the floppy motor.
; This code was shamelessly stolen from Linux.
Kill_Motor:
        mov     dx, 0x3f2
        xor     al, al
        out     dx, al
        ret

Init_PIC:
        ; Initialize master and slave PIC!
        mov     al, ICW1
        out     0x20, al                ; ICW1 to master
        call    Delay
        out     0xA0, al                ; ICW1 to slave
        call    Delay
        mov     al, ICW2_MASTER
        out     0x21, al                ; ICW2 to master
        call    Delay
        mov     al, ICW2_SLAVE
        out     0xA1, al                ; ICW2 to slave
        call    Delay
        mov     al, ICW3_MASTER
        out     0x21, al                ; ICW3 to master
        call    Delay
        mov     al, ICW3_SLAVE
        out     0xA1, al                ; ICW3 to slave
        call    Delay
        mov     al, ICW4
        out     0x21, al                ; ICW4 to master
        call    Delay
        out     0xA1, al                ; ICW4 to slave
        call    Delay
        mov     al, 0xff                ; mask all ints in slave
        out     0xA1, al                ; OCW1 to slave
        call    Delay
        mov     al, 0xfb                ; mask all ints but 2 in master
        out     0x21, al                ; OCW1 to master
        call    Delay
        ret

; Linux uses this code.
; The idea is that some systems issue port I/O instructions
; faster than the device hardware can deal with them.
Delay:
        jmp     .done
.done:  ret

; Enable the A20 address line, so we can correctly address
; memory above 1MB.
Enable_A20:
        mov     al, 0xD1
        out     0x64, al
        call    Delay
        mov     al, 0xDF
        out     0x60, al
        call    Delay
        ret


; ----------------------------------------------------------------------
; Setup data
; ----------------------------------------------------------------------

mem_size_kbytes: dw 0
mem_size_eblocks: dw 0


; ----------------------------------------------------------------------
; The GDT.  Creates flat 32-bit address space for the kernel
; code, data, and stack.  Note that this GDT is just used
; to create an environment where we can start running 32 bit
; code.  The kernel will create and manage its own GDT.
; ----------------------------------------------------------------------

; GDT initialization stuff
NUM_GDT_ENTRIES equ 3           ; number of entries in GDT
GDT_ENTRY_SZ equ 8              ; size of a single GDT entry

align 8, db 0
GDT:
        ; Descriptor 0 is not used
        dw 0
        dw 0
        dw 0
        dw 0

        ; Descriptor 1: kernel code segment
        dw 0xFFFF       ; bytes 0 and 1 of segment size
        dw 0x0000       ; bytes 0 and 1 of segment base address
        db 0x00         ; byte 2 of segment base address
        db 0x9A         ; present, DPL=0, non-system, code, non-conforming,
                        ;   readable, not accessed
        db 0xCF         ; granularity=page, 32 bit code, upper nibble of size
        db 0x00         ; byte 3 of segment base address

        ; Descriptor 2: kernel data and stack segment
        ; NOTE: what Intel calls an "expand-up" segment
        ; actually means that the stack will grow DOWN,
        ; towards lower memory.  So, we can use this descriptor
        ; for both data and stack references.
        dw 0xFFFF       ; bytes 0 and 1 of segment size
        dw 0x0000       ; bytes 0 and 1 of segment base address
        db 0x00         ; byte 2 of segment base address
        db 0x92         ; present, DPL=0, non-system, data, expand-up,
                        ;   writable, not accessed
        db 0xCF         ; granularity=page, big, upper nibble of size
        db 0x00         ; byte 3 of segment base address

GDT_Pointer:
        dw NUM_GDT_ENTRIES*GDT_ENTRY_SZ ; limit
        dd (SETUPSEG<<4) + GDT          ; base address

IDT_Pointer:
        dw 0
        dd 00

; Here's a bunch of information about your current kernel..
kernel_version: db      "1.0.0VMMHack"
                db      " ("
                db      "copyright"
                db      "@"
                db      "2008"
                db      ") "
                db      ""
                db      0

modelist: