ubuntu/vbox/r0drv/linux/memuserkernel-r0drv-linux.c

   1 /* $Id: memuserkernel-r0drv-linux.c $ */
   2 /** @file
   3  * IPRT - User & Kernel Memory, Ring-0 Driver, Linux.
   4  */
   5
   6 /*
   7  * Copyright (C) 2009-2016 Oracle Corporation
   8  *
   9  * This file is part of VirtualBox Open Source Edition (OSE), as
  10  * available from http://www.virtualbox.org. This file is free software;
  11  * you can redistribute it and/or modify it under the terms of the GNU
  12  * General Public License (GPL) as published by the Free Software
  13  * Foundation, in version 2 as it comes in the "COPYING" file of the
  14  * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
  15  * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
  16  *
  17  * The contents of this file may alternatively be used under the terms
  18  * of the Common Development and Distribution License Version 1.0
  19  * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
  20  * VirtualBox OSE distribution, in which case the provisions of the
  21  * CDDL are applicable instead of those of the GPL.
  22  *
  23  * You may elect to license modified versions of this file under the
  24  * terms and conditions of either the GPL or the CDDL or both.
  25  */
  26
  27
  28 /*********************************************************************************************************************************
  29 *   Header Files                                                                                                                 *
  30 *********************************************************************************************************************************/
  31 #include "the-linux-kernel.h"
  32 #include "internal/iprt.h"
  33
  34 #include <iprt/mem.h>
  35 #include <iprt/err.h>
  36
  37
  38 RTR0DECL(int) RTR0MemUserCopyFrom(void *pvDst, RTR3PTR R3PtrSrc, size_t cb)
  39 {
  40     IPRT_LINUX_SAVE_EFL_AC();
  41     if (RT_LIKELY(copy_from_user(pvDst, (void *)R3PtrSrc, cb) == 0))
  42     {
  43         IPRT_LINUX_RESTORE_EFL_AC();
  44         return VINF_SUCCESS;
  45     }
  46     IPRT_LINUX_RESTORE_EFL_AC();
  47     return VERR_ACCESS_DENIED;
  48 }
  49 RT_EXPORT_SYMBOL(RTR0MemUserCopyFrom);
  50
  51
  52 RTR0DECL(int) RTR0MemUserCopyTo(RTR3PTR R3PtrDst, void const *pvSrc, size_t cb)
  53 {
  54     IPRT_LINUX_SAVE_EFL_AC();
  55     if (RT_LIKELY(copy_to_user((void *)R3PtrDst, pvSrc, cb) == 0))
  56     {
  57         IPRT_LINUX_RESTORE_EFL_AC();
  58         return VINF_SUCCESS;
  59     }
  60     IPRT_LINUX_RESTORE_EFL_AC();
  61     return VERR_ACCESS_DENIED;
  62 }
  63 RT_EXPORT_SYMBOL(RTR0MemUserCopyTo);
  64
  65
  66 RTR0DECL(bool) RTR0MemUserIsValidAddr(RTR3PTR R3Ptr)
  67 {
  68     IPRT_LINUX_SAVE_EFL_AC();
  69     bool fRc = access_ok(VERIFY_READ, (void *)R3Ptr, 1);
  70     IPRT_LINUX_RESTORE_EFL_AC();
  71     return fRc;
  72 }
  73 RT_EXPORT_SYMBOL(RTR0MemUserIsValidAddr);
  74
  75
  76 RTR0DECL(bool) RTR0MemKernelIsValidAddr(void *pv)
  77 {
  78     /* Couldn't find a straight forward way of doing this... */
  79 #if defined(RT_ARCH_X86) && defined(CONFIG_X86_HIGH_ENTRY)
  80     return true; /* ?? */
  81 #elif defined(RT_ARCH_X86) || defined(RT_ARCH_AMD64)
  82     return (uintptr_t)pv >= PAGE_OFFSET;
  83 #else
  84 # error "PORT ME"
  85     return !access_ok(VERIFY_READ, pv, 1);
  86 #endif
  87 }
  88 RT_EXPORT_SYMBOL(RTR0MemKernelIsValidAddr);
  89
  90
  91 RTR0DECL(bool) RTR0MemAreKrnlAndUsrDifferent(void)
  92 {
  93 #if defined(RT_ARCH_X86) && defined(CONFIG_X86_HIGH_ENTRY) /* ?? */
  94     return false;
  95 #else
  96     return true;
  97 #endif
  98 }
  99 RT_EXPORT_SYMBOL(RTR0MemAreKrnlAndUsrDifferent);
 100
 101
 102 /**
 103  * Treats both source and destination as unsafe buffers.
 104  */
 105 static int rtR0MemKernelCopyLnxWorker(void *pvDst, void const *pvSrc, size_t cb)
 106 {
 107 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 5, 55)
 108 /* _ASM_EXTABLE was introduced in 2.6.25 from what I can tell. Using #ifndef
 109    here since it has to be a macro and you never know what someone might have
 110    backported to an earlier kernel release. */
 111 # ifndef _ASM_EXTABLE
 112 #  if ARCH_BITS == 32
 113 #   define _ASM_EXTABLE(a_Instr, a_Resume) \
 114     ".section __ex_table,\"a\"\n" \
 115     ".balign 4\n" \
 116     ".long   " #a_Instr "\n" \
 117     ".long   " #a_Resume "\n" \
 118     ".previous\n"
 119 #  else
 120 #   define _ASM_EXTABLE(a_Instr, a_Resume) \
 121     ".section __ex_table,\"a\"\n" \
 122     ".balign 8\n" \
 123     ".quad   " #a_Instr "\n" \
 124     ".quad   " #a_Resume "\n" \
 125     ".previous\n"
 126 #  endif
 127 # endif /* !_ASM_EXTABLE */
 128     int rc;
 129     IPRT_LINUX_SAVE_EFL_AC(); /* paranoia */
 130     if (!cb)
 131         return VINF_SUCCESS;
 132
 133     __asm__ __volatile__ ("cld\n"
 134                           "1:\n\t"
 135                           "rep; movsb\n"
 136                           "2:\n\t"
 137                           ".section .fixup,\"ax\"\n"
 138                           "3:\n\t"
 139                           "movl %4, %0\n"
 140                           ".previous\n"
 141                           _ASM_EXTABLE(1b, 3b)
 142                           : "=r" (rc),
 143                             "=D" (pvDst),
 144                             "=S" (pvSrc),
 145                             "=c" (cb)
 146                           : "i" (VERR_ACCESS_DENIED),
 147                             "0" (VINF_SUCCESS),
 148                             "1" (pvDst),
 149                             "2" (pvSrc),
 150                             "3" (cb)
 151                           : "memory");
 152     IPRT_LINUX_RESTORE_EFL_AC();
 153     return rc;
 154 #else
 155     return VERR_NOT_SUPPORTED;
 156 #endif
 157 }
 158
 159
 160 RTR0DECL(int) RTR0MemKernelCopyFrom(void *pvDst, void const *pvSrc, size_t cb)
 161 {
 162     return rtR0MemKernelCopyLnxWorker(pvDst, pvSrc, cb);
 163 }
 164 RT_EXPORT_SYMBOL(RTR0MemKernelCopyFrom);
 165
 166
 167 RTR0DECL(int) RTR0MemKernelCopyTo(void *pvDst, void const *pvSrc, size_t cb)
 168 {
 169     return rtR0MemKernelCopyLnxWorker(pvDst, pvSrc, cb);
 170 }
 171 RT_EXPORT_SYMBOL(RTR0MemKernelCopyTo);
 172