diff options
Diffstat (limited to 'src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPE32.asm')
| -rw-r--r-- | src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPE32.asm | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPE32.asm b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPE32.asm new file mode 100644 index 00000000..9030dd5b --- /dev/null +++ b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPE32.asm @@ -0,0 +1,179 @@ +; $Id: bs3-mode-SwitchToPE32.asm $ +;; @file +; BS3Kit - Bs3SwitchToPE32 +; + +; +; Copyright (C) 2007-2023 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>. +; +; The contents of this file may alternatively be used under the terms +; of the Common Development and Distribution License Version 1.0 +; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included +; in the VirtualBox 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. +; +; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 +; + +%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 + |