diff options
Diffstat (limited to 'src/VBox/VMM/VMMR0/VMMR0TripleFaultHackA.asm')
| -rw-r--r-- | src/VBox/VMM/VMMR0/VMMR0TripleFaultHackA.asm | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/src/VBox/VMM/VMMR0/VMMR0TripleFaultHackA.asm b/src/VBox/VMM/VMMR0/VMMR0TripleFaultHackA.asm new file mode 100644 index 00000000..64817920 --- /dev/null +++ b/src/VBox/VMM/VMMR0/VMMR0TripleFaultHackA.asm @@ -0,0 +1,264 @@ +; $Id: VMMR0TripleFaultHackA.asm $ +;; @file +; VMM - Host Context Ring 0, Assembly Code for The Triple Fault Debugging Hack. +; + +; +; Copyright (C) 2011-2019 Oracle Corporation +; +; This file is part of VirtualBox Open Source Edition (OSE), as +; available from http://www.virtualbox.org. This file is free software; +; you can redistribute it and/or modify it under the terms of the GNU +; General Public License (GPL) as published by the Free Software +; Foundation, in version 2 as it comes in the "COPYING" file of the +; VirtualBox OSE distribution. VirtualBox OSE is distributed in the +; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. +; + +;******************************************************************************* +;* 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 + |