| 1 | /* $Id: memuserkernel-r0drv-linux.c 100191 2023-06-16 08:04:11Z vboxsync $ */
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| 2 | /** @file
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| 3 | * IPRT - User & Kernel Memory, Ring-0 Driver, Linux.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2009-2023 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 "the-linux-kernel.h"
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| 42 | #include "internal/iprt.h"
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| 43 |
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| 44 | #include <iprt/mem.h>
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| 45 | #include <iprt/errcore.h>
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| 46 |
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| 47 |
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| 48 | RTR0DECL(int) RTR0MemUserCopyFrom(void *pvDst, RTR3PTR R3PtrSrc, size_t cb)
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| 49 | {
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| 50 | IPRT_LINUX_SAVE_EFL_AC();
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| 51 | if (RT_LIKELY(copy_from_user(pvDst, (void *)R3PtrSrc, cb) == 0))
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| 52 | {
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| 53 | IPRT_LINUX_RESTORE_EFL_AC();
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| 54 | return VINF_SUCCESS;
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| 55 | }
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| 56 | IPRT_LINUX_RESTORE_EFL_AC();
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| 57 | return VERR_ACCESS_DENIED;
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| 58 | }
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| 59 | RT_EXPORT_SYMBOL(RTR0MemUserCopyFrom);
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| 60 |
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| 61 |
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| 62 | RTR0DECL(int) RTR0MemUserCopyTo(RTR3PTR R3PtrDst, void const *pvSrc, size_t cb)
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| 63 | {
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| 64 | IPRT_LINUX_SAVE_EFL_AC();
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| 65 | if (RT_LIKELY(copy_to_user((void *)R3PtrDst, pvSrc, cb) == 0))
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| 66 | {
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| 67 | IPRT_LINUX_RESTORE_EFL_AC();
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| 68 | return VINF_SUCCESS;
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| 69 | }
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| 70 | IPRT_LINUX_RESTORE_EFL_AC();
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| 71 | return VERR_ACCESS_DENIED;
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| 72 | }
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| 73 | RT_EXPORT_SYMBOL(RTR0MemUserCopyTo);
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| 74 |
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| 75 |
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| 76 | RTR0DECL(bool) RTR0MemUserIsValidAddr(RTR3PTR R3Ptr)
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| 77 | {
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| 78 | IPRT_LINUX_SAVE_EFL_AC();
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| 79 | #if RTLNX_VER_MIN(5,0,0) || RTLNX_RHEL_MIN(8,1)
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| 80 | bool fRc = access_ok((void *)R3Ptr, 1);
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| 81 | #else
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| 82 | bool fRc = access_ok(VERIFY_READ, (void *)R3Ptr, 1);
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| 83 | #endif
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| 84 | IPRT_LINUX_RESTORE_EFL_AC();
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| 85 | return fRc;
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| 86 | }
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| 87 | RT_EXPORT_SYMBOL(RTR0MemUserIsValidAddr);
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| 88 |
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| 89 |
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| 90 | RTR0DECL(bool) RTR0MemKernelIsValidAddr(void *pv)
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| 91 | {
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| 92 | /* Couldn't find a straight forward way of doing this... */
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| 93 | #if defined(RT_ARCH_X86) && defined(CONFIG_X86_HIGH_ENTRY)
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| 94 | return true; /* ?? */
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| 95 | #elif defined(RT_ARCH_X86) || defined(RT_ARCH_AMD64) || defined(RT_ARCH_ARM64) || defined(RT_ARCH_ARM32)
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| 96 | return (uintptr_t)pv >= PAGE_OFFSET;
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| 97 | #else
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| 98 | # error "PORT ME"
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| 99 | #if RTLNX_VER_MIN(5,0,0) || RTLNX_RHEL_MIN(8,1)
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| 100 | return !access_ok(pv, 1);
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| 101 | #else
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| 102 | return !access_ok(VERIFY_READ, pv, 1);
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| 103 | #endif
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| 104 | #endif
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| 105 | }
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| 106 | RT_EXPORT_SYMBOL(RTR0MemKernelIsValidAddr);
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| 107 |
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| 108 |
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| 109 | RTR0DECL(bool) RTR0MemAreKrnlAndUsrDifferent(void)
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| 110 | {
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| 111 | #if defined(RT_ARCH_X86) && defined(CONFIG_X86_HIGH_ENTRY) /* ?? */
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| 112 | return false;
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| 113 | #else
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| 114 | return true;
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| 115 | #endif
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| 116 | }
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| 117 | RT_EXPORT_SYMBOL(RTR0MemAreKrnlAndUsrDifferent);
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| 118 |
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| 119 |
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| 120 | #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
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| 121 | /**
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| 122 | * Treats both source and destination as unsafe buffers.
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| 123 | */
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| 124 | static int rtR0MemKernelCopyLnxWorker(void *pvDst, void const *pvSrc, size_t cb)
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| 125 | {
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| 126 | # if RTLNX_VER_MIN(2,5,55)
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| 127 | /* _ASM_EXTABLE was introduced in 2.6.25 from what I can tell. Using #ifndef
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| 128 | here since it has to be a macro and you never know what someone might have
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| 129 | backported to an earlier kernel release. */
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| 130 | # ifndef _ASM_EXTABLE
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| 131 | # if ARCH_BITS == 32
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| 132 | # define _ASM_EXTABLE(a_Instr, a_Resume) \
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| 133 | ".section __ex_table,\"a\"\n" \
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| 134 | ".balign 4\n" \
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| 135 | ".long " #a_Instr "\n" \
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| 136 | ".long " #a_Resume "\n" \
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| 137 | ".previous\n"
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| 138 | # else
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| 139 | # define _ASM_EXTABLE(a_Instr, a_Resume) \
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| 140 | ".section __ex_table,\"a\"\n" \
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| 141 | ".balign 8\n" \
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| 142 | ".quad " #a_Instr "\n" \
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| 143 | ".quad " #a_Resume "\n" \
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| 144 | ".previous\n"
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| 145 | # endif
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| 146 | # endif /* !_ASM_EXTABLE */
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| 147 | int rc;
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| 148 | IPRT_LINUX_SAVE_EFL_AC(); /* paranoia */
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| 149 | if (!cb)
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| 150 | return VINF_SUCCESS;
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| 151 |
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| 152 | __asm__ __volatile__ ("cld\n"
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| 153 | "1:\n\t"
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| 154 | "rep; movsb\n"
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| 155 | "2:\n\t"
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| 156 | ".section .fixup,\"ax\"\n"
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| 157 | "3:\n\t"
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| 158 | "movl %4, %0\n\t"
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| 159 | "jmp 2b\n\t"
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| 160 | ".previous\n"
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| 161 | _ASM_EXTABLE(1b, 3b)
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| 162 | : "=r" (rc),
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| 163 | "=D" (pvDst),
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| 164 | "=S" (pvSrc),
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| 165 | "=c" (cb)
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| 166 | : "i" (VERR_ACCESS_DENIED),
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| 167 | "0" (VINF_SUCCESS),
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| 168 | "1" (pvDst),
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| 169 | "2" (pvSrc),
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| 170 | "3" (cb)
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| 171 | : "memory");
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| 172 | IPRT_LINUX_RESTORE_EFL_AC();
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| 173 | return rc;
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| 174 | # else
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| 175 | return VERR_NOT_SUPPORTED;
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| 176 | # endif
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| 177 | }
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| 178 |
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| 179 |
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| 180 | RTR0DECL(int) RTR0MemKernelCopyFrom(void *pvDst, void const *pvSrc, size_t cb)
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| 181 | {
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| 182 | return rtR0MemKernelCopyLnxWorker(pvDst, pvSrc, cb);
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| 183 | }
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| 184 | RT_EXPORT_SYMBOL(RTR0MemKernelCopyFrom);
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| 185 |
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| 186 |
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| 187 | RTR0DECL(int) RTR0MemKernelCopyTo(void *pvDst, void const *pvSrc, size_t cb)
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| 188 | {
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| 189 | return rtR0MemKernelCopyLnxWorker(pvDst, pvSrc, cb);
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| 190 | }
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| 191 | RT_EXPORT_SYMBOL(RTR0MemKernelCopyTo);
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| 192 | #endif /* !RT_ARCH_AMD64 && !RT_ARCH_X86 */
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| 193 |
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