1 | /* $Id: system-page-size-posix.cpp 100307 2023-06-28 10:17:34Z vboxsync $ */
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2 | /** @file
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3 | * IPRT - RTSystemGetPageSize(), RTSystemGetPageShift(), RTSystemGetPageOffsetMask() and RTSystemPageAlignSize(), Posix ring-3.
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4 | */
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5 |
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6 | /*
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7 | * Copyright (C) 2023 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 |
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38 | /*********************************************************************************************************************************
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39 | * Header Files *
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40 | *********************************************************************************************************************************/
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41 | #include <iprt/system.h>
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42 | #include "internal/iprt.h"
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43 | #include "internal/system.h"
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44 |
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45 | #include <iprt/asm.h>
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46 | #include <iprt/assert.h>
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47 | #include <iprt/errcore.h>
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48 |
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49 | #include <unistd.h>
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50 | #include <errno.h>
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51 |
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52 |
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53 | /*********************************************************************************************************************************
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54 | * Global Variables *
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55 | *********************************************************************************************************************************/
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56 | /** The page size used in bytes. */
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57 | static uint32_t g_cbPage = 0;
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58 | /** The page shift in bits. */
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59 | static uint32_t g_cPageShift = 0;
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60 | /** The page offset mask. */
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61 | static uintptr_t g_fPageOff = 0;
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62 |
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63 |
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64 | DECLHIDDEN(int) rtSystemInitPageSize(void)
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65 | {
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66 | long cbPage = sysconf(_SC_PAGESIZE);
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67 | if (cbPage == -1)
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68 | return RTErrConvertFromErrno(errno);
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69 |
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70 | /* Some sanity check to fend of bogus values (should not happen). */
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71 | AssertReturn(cbPage == _4K || cbPage == _16K || cbPage == _64K,
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72 | VERR_NOT_SUPPORTED);
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73 |
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74 | g_cbPage = (uint32_t)cbPage;
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75 | g_fPageOff = (uintptr_t)cbPage - 1;
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76 | g_cPageShift = ASMBitFirstSet(&g_cbPage, sizeof(uint32_t) * 8);
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77 | return VINF_SUCCESS;
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78 | }
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79 |
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80 |
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81 | RTDECL(uint32_t) RTSystemGetPageSize(void)
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82 | {
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83 | Assert(g_cbPage > 0);
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84 | return g_cbPage;
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85 | }
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86 |
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87 |
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88 | RTDECL(uint32_t) RTSystemGetPageShift(void)
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89 | {
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90 | Assert(g_cPageShift > 0);
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91 | return g_cPageShift;
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92 | }
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93 |
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94 |
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95 | RTDECL(uintptr_t) RTSystemGetPageOffsetMask(void)
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96 | {
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97 | Assert(g_fPageOff > 0);
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98 | return g_fPageOff;
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99 | }
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100 |
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101 |
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102 | RTDECL(size_t) RTSystemPageAlignSize(size_t cb)
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103 | {
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104 | Assert(g_cbPage > 0);
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105 | return RT_ALIGN_Z(cb, g_cbPage);
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106 | }
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