| 1 | ; $Id: bs3-cmn-RegSetTr.asm 82968 2020-02-04 10:35:17Z vboxsync $
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| 2 | ;; @file
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| 3 | ; BS3Kit - Bs3RegSetTr
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| 4 | ;
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| 5 |
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| 6 | ;
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| 7 | ; Copyright (C) 2007-2020 Oracle Corporation
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| 8 | ;
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| 9 | ; This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | ; available from http://www.virtualbox.org. This file is free software;
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| 11 | ; you can redistribute it and/or modify it under the terms of the GNU
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| 12 | ; General Public License (GPL) as published by the Free Software
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| 13 | ; Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | ; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | ; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | ;
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| 17 | ; The contents of this file may alternatively be used under the terms
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| 18 | ; of the Common Development and Distribution License Version 1.0
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| 19 | ; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 20 | ; VirtualBox OSE distribution, in which case the provisions of the
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| 21 | ; CDDL are applicable instead of those of the GPL.
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| 22 | ;
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| 23 | ; You may elect to license modified versions of this file under the
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| 24 | ; terms and conditions of either the GPL or the CDDL or both.
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| 25 | ;
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| 26 |
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| 27 | %include "bs3kit-template-header.mac"
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| 28 |
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| 29 |
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| 30 | BS3_EXTERN_CMN Bs3Syscall
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| 31 | %if TMPL_BITS == 16
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| 32 | BS3_EXTERN_DATA16 g_bBs3CurrentMode
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| 33 | %endif
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| 34 | BS3_EXTERN_SYSTEM16 Bs3Gdt
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| 35 | TMPL_BEGIN_TEXT
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| 36 |
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| 37 |
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| 38 | ;;
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| 39 | ; @cproto BS3_CMN_PROTO_STUB(void, Bs3RegSetTr,(uint16_t uValue));
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| 40 | ;
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| 41 | ; @param uValue The value to set.
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| 42 |
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| 43 | ; @remarks Does not require 20h of parameter scratch space in 64-bit mode.
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| 44 | ;
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| 45 | ; @uses No GPRs.
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| 46 | ;
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| 47 | BS3_PROC_BEGIN_CMN Bs3RegSetTr, BS3_PBC_HYBRID_SAFE
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| 48 | BS3_CALL_CONV_PROLOG 1
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| 49 | push xBP
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| 50 | mov xBP, xSP
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| 51 | push xDX
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| 52 | push xAX
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| 53 | push xDI
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| 54 |
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| 55 | mov dx, [xBP + xCB + cbCurRetAddr]
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| 56 |
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| 57 | %if TMPL_BITS == 16
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| 58 | ; If V8086 mode we have to go thru a syscall.
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| 59 | test byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], BS3_MODE_CODE_V86
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| 60 | jnz .via_system_call
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| 61 | %endif
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| 62 | ; If not in ring-0, we have to make a system call.
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| 63 | mov ax, ss
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| 64 | and ax, X86_SEL_RPL
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| 65 | jnz .via_system_call
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| 66 |
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| 67 | ; Before we can load it, we must mark it non-busy.
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| 68 | %if TMPL_BITS == 16
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| 69 | push ds
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| 70 | mov ax, BS3_SEL_SYSTEM16
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| 71 | mov ds, ax
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| 72 | add xDI, Bs3Gdt wrt BS3SYSTEM16
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| 73 | %else
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| 74 | add xDI, Bs3Gdt wrt FLAT
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| 75 | %endif
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| 76 | add xDI, X86DESCGENERIC_BIT_OFF_TYPE / 8
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| 77 | and byte [xDI], ~(X86_SEL_TYPE_SYS_TSS_BUSY_MASK << (X86DESCGENERIC_BIT_OFF_TYPE % 8))
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| 78 | %if TMPL_BITS == 16
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| 79 | pop ds
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| 80 | %endif
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| 81 | ltr dx
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| 82 | jmp .return
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| 83 |
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| 84 | .via_system_call:
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| 85 | mov ax, BS3_SYSCALL_SET_TR
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| 86 | call Bs3Syscall
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| 87 |
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| 88 | .return:
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| 89 | pop xDI
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| 90 | pop xAX
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| 91 | pop xDX
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| 92 | pop xBP
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| 93 | BS3_CALL_CONV_EPILOG 1
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| 94 | BS3_HYBRID_RET
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| 95 | BS3_PROC_END_CMN Bs3RegSetTr
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| 96 |
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