| 1 | ; $Id: bs3-cmn-RegGetCr4.asm 106061 2024-09-16 14:03:52Z vboxsync $
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| 2 | ;; @file
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| 3 | ; BS3Kit - Bs3RegGetCr4
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| 4 | ;
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| 5 |
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| 6 | ;
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| 7 | ; Copyright (C) 2007-2024 Oracle and/or its affiliates.
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| 8 | ;
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| 9 | ; This file is part of VirtualBox base platform packages, as
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| 10 | ; available from https://www.virtualbox.org.
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| 11 | ;
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| 12 | ; This program is free software; you can redistribute it and/or
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| 13 | ; modify it under the terms of the GNU General Public License
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| 14 | ; as published by the Free Software Foundation, in version 3 of the
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| 15 | ; License.
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| 16 | ;
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| 17 | ; This program is distributed in the hope that it will be useful, but
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| 18 | ; WITHOUT ANY WARRANTY; without even the implied warranty of
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| 19 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 20 | ; General Public License for more details.
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| 21 | ;
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| 22 | ; You should have received a copy of the GNU General Public License
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| 23 | ; along with this program; if not, see <https://www.gnu.org/licenses>.
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| 24 | ;
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| 25 | ; The contents of this file may alternatively be used under the terms
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| 26 | ; of the Common Development and Distribution License Version 1.0
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| 27 | ; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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| 28 | ; in the VirtualBox distribution, in which case the provisions of the
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| 29 | ; CDDL are applicable instead of those of the GPL.
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| 30 | ;
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| 31 | ; You may elect to license modified versions of this file under the
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| 32 | ; terms and conditions of either the GPL or the CDDL or both.
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| 33 | ;
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| 34 | ; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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| 35 | ;
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| 36 |
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| 37 | %include "bs3kit-template-header.mac"
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| 38 |
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| 39 |
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| 40 | BS3_EXTERN_CMN Bs3Panic
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| 41 | BS3_EXTERN_CMN Bs3Syscall
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| 42 | %if TMPL_BITS == 16
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| 43 | BS3_EXTERN_DATA16 g_bBs3CurrentMode
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| 44 | %endif
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| 45 | TMPL_BEGIN_TEXT
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| 46 |
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| 47 |
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| 48 | ;;
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| 49 | ; @cproto BS3_CMN_PROTO_STUB(RTCCUINTXREG, Bs3RegGetCr4,(void));
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| 50 | ;
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| 51 | ; @returns Register value.
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| 52 | ; @remarks Does not require 20h of parameter scratch space in 64-bit mode.
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| 53 | ;
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| 54 | ; @uses No GPRs (only return full register(s)).
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| 55 | ;
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| 56 | BS3_PROC_BEGIN_CMN Bs3RegGetCr4, BS3_PBC_HYBRID_SAFE
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| 57 | BS3_CALL_CONV_PROLOG 0
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| 58 | push xBP
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| 59 | mov xBP, xSP
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| 60 |
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| 61 | %if TMPL_BITS == 16
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| 62 | ; If V8086 mode we have to go thru a syscall.
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| 63 | test byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], BS3_MODE_CODE_V86
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| 64 | jnz .via_system_call
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| 65 | cmp byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], BS3_MODE_RM
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| 66 | je .direct_access
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| 67 | %endif
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| 68 | ; If not in ring-0, we have to make a system call.
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| 69 | mov ax, ss
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| 70 | and ax, X86_SEL_RPL
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| 71 | jnz .via_system_call
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| 72 |
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| 73 | .direct_access:
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| 74 | mov sAX, cr4
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| 75 | TONLY16 mov edx, eax
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| 76 | TONLY16 shr edx, 16
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| 77 | jmp .return
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| 78 |
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| 79 | .via_system_call:
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| 80 | mov xAX, BS3_SYSCALL_GET_CRX
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| 81 | mov dl, 4
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| 82 | call Bs3Syscall
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| 83 |
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| 84 | .return:
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| 85 | pop xBP
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| 86 | BS3_CALL_CONV_EPILOG 0
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| 87 | BS3_HYBRID_RET
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| 88 | BS3_PROC_END_CMN Bs3RegGetCr4
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| 89 |
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