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|
; $Id: VMMR0TripleFaultHackA.asm $
;; @file
; VMM - Host Context Ring 0, Assembly Code for The Triple Fault Debugging Hack.
;
;
; Copyright (C) 2011-2023 Oracle and/or its affiliates.
;
; This file is part of VirtualBox base platform packages, as
; available from https://www.virtualbox.org.
;
; This program is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public License
; as published by the Free Software Foundation, in version 3 of the
; License.
;
; This program is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, see <https://www.gnu.org/licenses>.
;
; SPDX-License-Identifier: GPL-3.0-only
;
;*******************************************************************************
;* Header Files *
;*******************************************************************************
%include "VBox/asmdefs.mac"
BEGINCODE
GLOBALNAME vmmR0TripleFaultHackStart
%define CALC_ADDR(a_Addr) ( (a_Addr) - NAME(vmmR0TripleFaultHackStart) + 07000h )
BITS 16
BEGINPROC vmmR0TripleFaultHack
; Set up stack.
cli ; paranoia
mov sp, 0ffffh
mov ax, cs
mov ss, ax
mov ds, ax
mov es, ax
cld ; paranoia
COM_INIT
; Beep and say hello to the post-reset world.
call NAME(vmmR0TripleFaultHackBeep)
mov si, CALC_ADDR(.s_szHello)
call NAME(vmmR0TripleFaultHackPrint)
.forever:
hlt
jmp .forever
.s_szHello:
db 'Hello post-reset world', 0ah, 0dh, 0
ENDPROC vmmR0TripleFaultHack
;; ds:si = zero terminated string.
BEGINPROC vmmR0TripleFaultHackPrint
push eax
push esi
.outer_loop:
lodsb
cmp al, 0
je .done
call NAME(vmmR0TripleFaultHackPrintCh)
jmp .outer_loop
.done:
pop esi
pop eax
ret
ENDPROC vmmR0TripleFaultHackPrint
;; al = char to print
BEGINPROC vmmR0TripleFaultHackPrintCh
push eax
push edx
push ecx
mov ah, al ; save char.
; Wait for status.
mov ecx, _1G
mov dx, VBOX_UART_BASE + 5
.pre_status:
in al, dx
test al, 20h
jnz .put_char
dec ecx
jnz .pre_status
; Write the character.
.put_char:
mov al, ah
mov dx, VBOX_UART_BASE
out dx, al
; Wait for status.
mov ecx, _1G
mov dx, VBOX_UART_BASE + 5
.post_status:
in al, dx
test al, 20h
jnz .done
dec ecx
jnz .post_status
.done:
pop ecx
pop edx
pop eax
ret
ENDPROC vmmR0TripleFaultHackPrintCh
;;
; make a 440 BEEP.
BEGINPROC vmmR0TripleFaultHackBeep
push eax
push edx
push ecx
; program PIT(1) and stuff.
mov al, 10110110b
out 43h, al
mov ax, 0a79h ; A = 440
out 42h, al
shr ax, 8
out 42h, al
in al, 61h
or al, 3
out 61h, al
; delay
mov ecx, _1G
.delay:
inc ecx
dec ecx
dec ecx
jnz .delay
; shut up speaker.
in al, 61h
and al, 11111100b
out 61h, al
.done:
pop ecx
pop edx
pop eax
ret
ENDPROC vmmR0TripleFaultHackBeep
GLOBALNAME vmmR0TripleFaultHackEnd
;;;
;;;
;;;
;;;
;;;
BITS ARCH_BITS
BEGINPROC vmmR0TripleFaultHackKbdWait
push xAX
.check_status:
in al, 64h
test al, 1 ; KBD_STAT_OBF
jnz .read_data_and_status
test al, 2 ; KBD_STAT_IBF
jnz .check_status
pop xAX
ret
.read_data_and_status:
in al, 60h
jmp .check_status
ENDPROC vmmR0TripleFaultHackKbdWait
BEGINPROC vmmR0TripleFaultHackKbdRead
out 64h, al ; Write the command.
.check_status:
in al, 64h
test al, 1 ; KBD_STAT_OBF
jz .check_status
in al, 60h ; Read the data.
ret
ENDPROC vmmR0TripleFaultHackKbdRead
BEGINPROC vmmR0TripleFaultHackKbdWrite
out 64h, al ; Write the command.
call NAME(vmmR0TripleFaultHackKbdWait)
xchg al, ah
out 60h, al ; Write the data.
call NAME(vmmR0TripleFaultHackKbdWait)
xchg al, ah
ret
ENDPROC vmmR0TripleFaultHackKbdWrite
BEGINPROC vmmR0TripleFaultHackTripleFault
push xAX
push xSI
xor eax, eax
push xAX
push xAX
push xAX
push xAX
COM_CHAR 'B'
COM_CHAR 'y'
COM_CHAR 'e'
COM_CHAR '!'
COM_CHAR 0ah
COM_CHAR 0dh
;call NAME(vmmR0TripleFaultHackBeep32)
%if 1
lidt [xSP]
%elif 0
in al, 92h
or al, 1
out 92h, al
in al, 92h
cli
hlt
%else
mov al, 0d0h ; KBD_CCMD_READ_OUTPORT
call NAME(vmmR0TripleFaultHackKbdRead)
mov ah, 0feh
and ah, al
mov al, 0d1h ; KBD_CCMD_WRITE_OUTPORT
call NAME(vmmR0TripleFaultHackKbdWrite)
cli
hlt
%endif
int3
pop xAX
pop xAX
pop xAX
pop xAX
pop xSI
pop xAX
ret
ENDPROC vmmR0TripleFaultHackTripleFault
|
