1 | /* $Id: bs3-cmn-Trap16Init.c 59984 2016-03-11 00:56:10Z vboxsync $ */
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2 | /** @file
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3 | * BS3Kit - Bs3Trap16Init
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4 | */
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5 |
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6 | /*
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7 | * Copyright (C) 2007-2016 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 | /*********************************************************************************************************************************
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28 | * Header Files *
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29 | *********************************************************************************************************************************/
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30 | #include "bs3kit-template-header.h"
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31 |
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32 |
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33 | /*********************************************************************************************************************************
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34 | * Global Variables *
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35 | *********************************************************************************************************************************/
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36 | /* We ASSUME that BS3CODE16 is 64KB aligned, so the low 16-bit of the
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37 | flat address matches. Also, these symbols are defined both with
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38 | and without underscore prefixes. */
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39 | extern BS3_DECL(void) BS3_FAR_CODE Bs3Trap16DoubleFaultHandler80386(void);
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40 | extern BS3_DECL(void) BS3_FAR_CODE Bs3Trap16DoubleFaultHandler80286(void);
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41 | extern BS3_DECL(void) BS3_FAR_CODE Bs3Trap16GenericEntries(void);
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42 |
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43 | /* These two are ugly. Need data access for patching purposes. */
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44 | extern uint8_t BS3_FAR_DATA bs3Trap16GenericTrapOrInt[];
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45 | extern uint8_t BS3_FAR_DATA bs3Trap16GenericTrapErrCode[];
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46 |
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47 |
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48 | BS3_DECL(void) Bs3Trap16Init(bool f386Plus)
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49 | {
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50 | X86TSS16 BS3_FAR *pTss;
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51 | unsigned iIdt;
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52 |
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53 | /*
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54 | * If 386 or later, patch the trap handler code to not jump to the 80286
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55 | * code but continue with the next instruction (the 386+ code).
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56 | */
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57 | if (f386Plus)
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58 | {
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59 | bs3Trap16GenericTrapErrCode[1] = 0;
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60 | bs3Trap16GenericTrapErrCode[2] = 0;
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61 | bs3Trap16GenericTrapOrInt[1] = 0;
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62 | bs3Trap16GenericTrapOrInt[2] = 0;
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63 | }
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64 |
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65 | /*
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66 | * IDT entries, except the system call gate.
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67 | */
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68 | for (iIdt = 0; iIdt < BS3_TRAP_SYSCALL; iIdt++)
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69 | Bs3Trap16SetGate(iIdt, X86_SEL_TYPE_SYS_286_INT_GATE, 0 /*bDpl*/,
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70 | BS3_SEL_R0_CS16, (uint16_t)(uintptr_t)Bs3Trap16GenericEntries + iIdt * 8, 0 /*cParams*/);
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71 | for (iIdt = BS3_TRAP_SYSCALL + 1; iIdt < 256; iIdt++)
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72 | Bs3Trap16SetGate(iIdt, X86_SEL_TYPE_SYS_286_INT_GATE, 0 /*bDpl*/,
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73 | BS3_SEL_R0_CS16, (uint16_t)(uintptr_t)Bs3Trap16GenericEntries + iIdt * 8, 0 /*cParams*/);
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74 |
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75 | /*
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76 | * Initialize the normal TSS so we can do ring transitions via the IDT.
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77 | */
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78 | pTss = &BS3_DATA_NM(Bs3Tss16);
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79 | Bs3MemZero(pTss, sizeof(*pTss));
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80 | pTss->sp0 = BS3_ADDR_STACK_R0;
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81 | pTss->ss0 = BS3_SEL_R0_SS16;
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82 | pTss->sp1 = BS3_ADDR_STACK_R1;
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83 | pTss->ss1 = BS3_SEL_R1_SS16 | 1;
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84 | pTss->sp2 = BS3_ADDR_STACK_R2;
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85 | pTss->ss2 = BS3_SEL_R2_SS16 | 2;
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86 |
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87 | /*
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88 | * Initialize the double fault TSS.
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89 | * cr3 is filled in by switcher code, when needed.
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90 | */
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91 | pTss = &BS3_DATA_NM(Bs3Tss16DoubleFault);
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92 | Bs3MemZero(pTss, sizeof(*pTss));
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93 | pTss->sp0 = BS3_ADDR_STACK_R0;
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94 | pTss->ss0 = BS3_SEL_R0_SS16;
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95 | pTss->sp1 = BS3_ADDR_STACK_R1;
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96 | pTss->ss1 = BS3_SEL_R1_SS16 | 1;
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97 | pTss->sp2 = BS3_ADDR_STACK_R2;
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98 | pTss->ss2 = BS3_SEL_R2_SS16 | 2;
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99 | pTss->ip = (uint16_t)(uintptr_t)(f386Plus ? &Bs3Trap16DoubleFaultHandler80386 : &Bs3Trap16DoubleFaultHandler80286);
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100 | pTss->flags = X86_EFL_1;
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101 | pTss->sp = BS3_ADDR_STACK_R0_IST1;
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102 | pTss->es = BS3_SEL_R0_DS16;
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103 | pTss->ds = BS3_SEL_R0_DS16;
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104 | pTss->cs = BS3_SEL_R0_CS16;
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105 | pTss->ss = BS3_SEL_R0_SS16;
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106 | pTss->dx = f386Plus;
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107 |
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108 | Bs3Trap16SetGate(X86_XCPT_DF, X86_SEL_TYPE_SYS_TASK_GATE, 0 /*bDpl*/, BS3_SEL_TSS16_DF, 0, 0 /*cParams*/);
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109 | }
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110 |
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