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|
; $Id: bs3-mode-SwitchToLM32.asm $
;; @file
; BS3Kit - Bs3SwitchToLM32
;
;
; 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 long mode from any other mode.
;
; @cproto BS3_DECL(void) Bs3SwitchToLM32(void);
;
; @uses Nothing (except possibly high 32-bit and/or upper 64-bit register parts).
;
; @remarks There are no IDT or TSS differences between LM16, LM32 and LM64 (unlike
; PE16 & PE32, PP16 & PP32, and PAE16 & PAE32).
;
; @remarks Obviously returns to 32-bit mode, even if the caller was in 16-bit
; or 64-bit mode. It doesn't not preserve the callers ring, but
; instead changes to ring-0.
;
; @remarks Does not require 20h of parameter scratch space in 64-bit mode.
;
BS3_GLOBAL_NAME_EX TMPL_NM(Bs3SwitchToLM32_Safe), function, 0
BS3_PROC_BEGIN_MODE Bs3SwitchToLM32, BS3_PBC_NEAR
%ifdef TMPL_LM32
ret
%elifdef TMPL_CMN_LM
;
; Already in long mode, just switch to 32-bit.
;
extern BS3_CMN_NM(Bs3SwitchTo32Bit)
jmp BS3_CMN_NM(Bs3SwitchTo32Bit)
%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](Bs3SwitchToLM32)
jmp %[BS3_MODE_R0_NM_ %+ TMPL_MODE](Bs3SwitchToLM32)
%else
%if TMPL_BITS == 16
push word 0 ; save space for extending the return value.
%endif
;
; Switch to 32-bit protected mode (for identify mapped pages).
;
extern TMPL_NM(Bs3SwitchToPE32)
call TMPL_NM(Bs3SwitchToPE32)
BS3_SET_BITS 32
%if TMPL_BITS == 16
jmp .thirty_two_bit_segment
BS3_BEGIN_TEXT32
BS3_GLOBAL_LOCAL_LABEL .thirty_two_bit_segment
%endif
push eax
push ecx
push edx
pushfd
;
; Make sure both PAE and PSE are enabled (requires pentium pro).
;
mov eax, cr4
mov ecx, eax
or eax, X86_CR4_PAE | X86_CR4_PSE
cmp eax, ecx
je .cr4_is_fine
mov cr4, eax
.cr4_is_fine:
;
; Get the page directory (returned in eax).
; Will lazy init page tables.
;
extern NAME(Bs3PagingGetRootForLM64_pe32)
call NAME(Bs3PagingGetRootForLM64_pe32)
cli
mov cr3, eax
;
; Enable long mode in EFER.
;
mov ecx, MSR_K6_EFER
rdmsr
or eax, MSR_K6_EFER_LME
wrmsr
;
; Enable paging and thereby activating LM64.
;
BS3_EXTERN_SYSTEM16 Bs3Lgdt_Gdt
BS3_BEGIN_TEXT32
mov eax, cr0
or eax, X86_CR0_PG
mov cr0, eax
jmp .in_lm32
.in_lm32:
;
; Call rountine for doing mode specific setups.
;
extern NAME(Bs3EnteredMode_lm32)
call NAME(Bs3EnteredMode_lm32)
;
; Load full 64-bit GDT base address from 64-bit segment.
;
jmp dword BS3_SEL_R0_CS64:.load_full_gdt_base wrt FLAT
.load_full_gdt_base:
BS3_SET_BITS 64
lgdt [Bs3Lgdt_Gdt wrt FLAT]
push BS3_SEL_R0_CS32
push .back_to_32bit wrt FLAT
o64 retf
.back_to_32bit:
BS3_SET_BITS 32
;
; Restore ecx, eax and flags (IF).
;
%if TMPL_BITS == 16
movzx eax, word [esp + 16 + 2] ; Load return address.
add eax, BS3_ADDR_BS3TEXT16 ; Convert it to a flat address.
mov [esp + 16], eax ; Store it in the place right for 32-bit returns.
%endif
popfd
pop edx
pop ecx
pop eax
ret
%if TMPL_BITS != 32
TMPL_BEGIN_TEXT
%endif
%endif
BS3_PROC_END_MODE Bs3SwitchToLM32
%if TMPL_BITS == 16
;;
; Custom far stub.
BS3_BEGIN_TEXT16_FARSTUBS
BS3_PROC_BEGIN_MODE Bs3SwitchToLM32, BS3_PBC_FAR
inc bp
push bp
mov bp, sp
; Call the real thing.
call TMPL_NM(Bs3SwitchToLM32)
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 Bs3SwitchToLM32
%endif
|
