Current File : //usr/src/vboxhost-6.0.14/vboxdrv/r0drv/linux/memuserkernel-r0drv-linux.c
/* $Id: memuserkernel-r0drv-linux.c 133264 2019-09-11 09:56:19Z paulson $ */
/** @file
* IPRT - User & Kernel Memory, Ring-0 Driver, Linux.
*/
/*
* Copyright (C) 2009-2019 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#include "the-linux-kernel.h"
#include "internal/iprt.h"
#include <iprt/mem.h>
#include <iprt/errcore.h>
RTR0DECL(int) RTR0MemUserCopyFrom(void *pvDst, RTR3PTR R3PtrSrc, size_t cb)
{
IPRT_LINUX_SAVE_EFL_AC();
if (RT_LIKELY(copy_from_user(pvDst, (void *)R3PtrSrc, cb) == 0))
{
IPRT_LINUX_RESTORE_EFL_AC();
return VINF_SUCCESS;
}
IPRT_LINUX_RESTORE_EFL_AC();
return VERR_ACCESS_DENIED;
}
RT_EXPORT_SYMBOL(RTR0MemUserCopyFrom);
RTR0DECL(int) RTR0MemUserCopyTo(RTR3PTR R3PtrDst, void const *pvSrc, size_t cb)
{
IPRT_LINUX_SAVE_EFL_AC();
if (RT_LIKELY(copy_to_user((void *)R3PtrDst, pvSrc, cb) == 0))
{
IPRT_LINUX_RESTORE_EFL_AC();
return VINF_SUCCESS;
}
IPRT_LINUX_RESTORE_EFL_AC();
return VERR_ACCESS_DENIED;
}
RT_EXPORT_SYMBOL(RTR0MemUserCopyTo);
RTR0DECL(bool) RTR0MemUserIsValidAddr(RTR3PTR R3Ptr)
{
IPRT_LINUX_SAVE_EFL_AC();
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 0, 0) || defined(RHEL_81)
bool fRc = access_ok((void *)R3Ptr, 1);
#else
bool fRc = access_ok(VERIFY_READ, (void *)R3Ptr, 1);
#endif
IPRT_LINUX_RESTORE_EFL_AC();
return fRc;
}
RT_EXPORT_SYMBOL(RTR0MemUserIsValidAddr);
RTR0DECL(bool) RTR0MemKernelIsValidAddr(void *pv)
{
/* Couldn't find a straight forward way of doing this... */
#if defined(RT_ARCH_X86) && defined(CONFIG_X86_HIGH_ENTRY)
return true; /* ?? */
#elif defined(RT_ARCH_X86) || defined(RT_ARCH_AMD64)
return (uintptr_t)pv >= PAGE_OFFSET;
#else
# error "PORT ME"
#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 0, 0) || defined(RHEL_81)
return !access_ok(pv, 1);
#else
return !access_ok(VERIFY_READ, pv, 1);
#endif /* LINUX_VERSION_CODE */
#endif
}
RT_EXPORT_SYMBOL(RTR0MemKernelIsValidAddr);
RTR0DECL(bool) RTR0MemAreKrnlAndUsrDifferent(void)
{
#if defined(RT_ARCH_X86) && defined(CONFIG_X86_HIGH_ENTRY) /* ?? */
return false;
#else
return true;
#endif
}
RT_EXPORT_SYMBOL(RTR0MemAreKrnlAndUsrDifferent);
/**
* Treats both source and destination as unsafe buffers.
*/
static int rtR0MemKernelCopyLnxWorker(void *pvDst, void const *pvSrc, size_t cb)
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 5, 55)
/* _ASM_EXTABLE was introduced in 2.6.25 from what I can tell. Using #ifndef
here since it has to be a macro and you never know what someone might have
backported to an earlier kernel release. */
# ifndef _ASM_EXTABLE
# if ARCH_BITS == 32
# define _ASM_EXTABLE(a_Instr, a_Resume) \
".section __ex_table,\"a\"\n" \
".balign 4\n" \
".long " #a_Instr "\n" \
".long " #a_Resume "\n" \
".previous\n"
# else
# define _ASM_EXTABLE(a_Instr, a_Resume) \
".section __ex_table,\"a\"\n" \
".balign 8\n" \
".quad " #a_Instr "\n" \
".quad " #a_Resume "\n" \
".previous\n"
# endif
# endif /* !_ASM_EXTABLE */
int rc;
IPRT_LINUX_SAVE_EFL_AC(); /* paranoia */
if (!cb)
return VINF_SUCCESS;
__asm__ __volatile__ ("cld\n"
"1:\n\t"
"rep; movsb\n"
"2:\n\t"
".section .fixup,\"ax\"\n"
"3:\n\t"
"movl %4, %0\n\t"
"jmp 2b\n\t"
".previous\n"
_ASM_EXTABLE(1b, 3b)
: "=r" (rc),
"=D" (pvDst),
"=S" (pvSrc),
"=c" (cb)
: "i" (VERR_ACCESS_DENIED),
"0" (VINF_SUCCESS),
"1" (pvDst),
"2" (pvSrc),
"3" (cb)
: "memory");
IPRT_LINUX_RESTORE_EFL_AC();
return rc;
#else
return VERR_NOT_SUPPORTED;
#endif
}
RTR0DECL(int) RTR0MemKernelCopyFrom(void *pvDst, void const *pvSrc, size_t cb)
{
return rtR0MemKernelCopyLnxWorker(pvDst, pvSrc, cb);
}
RT_EXPORT_SYMBOL(RTR0MemKernelCopyFrom);
RTR0DECL(int) RTR0MemKernelCopyTo(void *pvDst, void const *pvSrc, size_t cb)
{
return rtR0MemKernelCopyLnxWorker(pvDst, pvSrc, cb);
}
RT_EXPORT_SYMBOL(RTR0MemKernelCopyTo);
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