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|
; $Id: bs3-mode-SwitchToPE32.asm $
;; @file
; BS3Kit - Bs3SwitchToPE32
;
;
; Copyright (C) 2007-2019 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.
;
; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
; VirtualBox OSE distribution, in which case the provisions of the
; CDDL are applicable instead of those of the GPL.
;
; You may elect to license modified versions of this file under the
; terms and conditions of either the GPL or the CDDL or both.
;
%include "bs3kit-template-header.mac"
;;
; Switch to 32-bit unpaged protected mode from any other mode.
;
; @cproto BS3_DECL(void) Bs3SwitchToPE32(void);
;
; @uses Nothing (except high 32-bit register parts), upper part of ESP is
; cleared if caller is in 16-bit mode.
;
; @remarks Obviously returns to 32-bit mode, even if the caller was
; in 16-bit or 64-bit mode.
;
; @remarks Does not require 20h of parameter scratch space in 64-bit mode.
;
BS3_GLOBAL_NAME_EX TMPL_NM(Bs3SwitchToPE32_Safe), function, 0
BS3_PROC_BEGIN_MODE Bs3SwitchToPE32, BS3_PBC_NEAR
%ifdef TMPL_PE32
ret
%elif BS3_MODE_IS_V86(TMPL_MODE)
;
; V8086 - Switch to 16-bit ring-0 and call worker for that mode.
;
extern BS3_CMN_NM(Bs3SwitchToRing0)
call BS3_CMN_NM(Bs3SwitchToRing0)
extern %[BS3_MODE_R0_NM_ %+ TMPL_MODE](Bs3SwitchToPE32)
jmp %[BS3_MODE_R0_NM_ %+ TMPL_MODE](Bs3SwitchToPE32)
%else
;
; Switch to real mode.
;
%if TMPL_BITS != 32
%if TMPL_BITS > 32
shl xPRE [xSP], 32 ; Adjust the return address from 64-bit to 32-bit.
add rsp, xCB - 4
%else
push word 0 ; Reserve space to expand the return address.
%endif
%endif
%if TMPL_BITS != 16
; Must be in 16-bit segment when calling Bs3SwitchTo16Bit.
jmp .sixteen_bit_segment
BS3_BEGIN_TEXT16
BS3_SET_BITS TMPL_BITS
BS3_GLOBAL_LOCAL_LABEL .sixteen_bit_segment
%endif
;
; Switch to real mode.
;
extern TMPL_NM(Bs3SwitchToRM)
call TMPL_NM(Bs3SwitchToRM)
BS3_SET_BITS 16
push eax
pushfd
cli
;
; Load the GDT and enable PE32.
;
BS3_EXTERN_SYSTEM16 Bs3LgdtDef_Gdt
BS3_EXTERN_SYSTEM16 Bs3Lgdt_Gdt
BS3_BEGIN_TEXT16
mov ax, BS3SYSTEM16
mov ds, ax
lgdt [Bs3LgdtDef_Gdt] ; Will only load 24-bit base!
mov eax, cr0
or eax, X86_CR0_PE
mov cr0, eax
jmp BS3_SEL_R0_CS32:dword .thirty_two_bit wrt FLAT
BS3_BEGIN_TEXT32
BS3_GLOBAL_LOCAL_LABEL .thirty_two_bit
;
; Convert the (now) real mode stack pointer to 32-bit flat.
;
xor eax, eax
mov ax, ss
shl eax, 4
and esp, 0ffffh
add esp, eax
mov ax, BS3_SEL_R0_SS32
mov ss, ax
;
; Call rountine for doing mode specific setups.
;
extern NAME(Bs3EnteredMode_pe32)
call NAME(Bs3EnteredMode_pe32)
; Load full 32-bit GDT base address.
lgdt [Bs3Lgdt_Gdt wrt FLAT]
;
; Restore eax and flags (IF).
;
%if TMPL_BITS < 32
and esp, 0ffffh ; Make sure the high word is zero.
movzx eax, word [esp + 8 + 2] ; Load return address.
add eax, BS3_ADDR_BS3TEXT16 ; Convert it to a flat address.
mov [esp + 8], eax ; Store it in the place right for 32-bit returns.
%endif
popfd
pop eax
ret
%if TMPL_BITS != 32
TMPL_BEGIN_TEXT
%endif
%endif
BS3_PROC_END_MODE Bs3SwitchToPE32
%if TMPL_BITS == 16
;;
; Custom far stub.
BS3_BEGIN_TEXT16_FARSTUBS
BS3_PROC_BEGIN_MODE Bs3SwitchToPE32, BS3_PBC_FAR
inc bp
push bp
mov bp, sp
; Call the real thing.
call TMPL_NM(Bs3SwitchToPE32)
BS3_SET_BITS 32
; Jmp to common code for the tedious conversion.
%if BS3_MODE_IS_RM_OR_V86(TMPL_MODE)
extern _Bs3SwitchHlpConvRealModeRetfPopBpDecBpAndReturn_c32
jmp _Bs3SwitchHlpConvRealModeRetfPopBpDecBpAndReturn_c32
%else
extern _Bs3SwitchHlpConvProtModeRetfPopBpDecBpAndReturn_c32
jmp _Bs3SwitchHlpConvProtModeRetfPopBpDecBpAndReturn_c32
%endif
BS3_SET_BITS 16
BS3_PROC_END_MODE Bs3SwitchToPE32
%endif
|
