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Kernel: Introduce the MemoryDevice

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This is a character device that is being used by the dmidecode utility.
We only allow to map the BIOS ROM area to userspace with this device.
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Liav A 2021-01-29 14:03:25 +02:00 • committed by Andreas Kling
parent df59b80e23
commit 5ab1864497
6 changed files with 235 additions and 0 deletions
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78
Kernel/Devices/MemoryDevice.cpp Normal file
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/*
* Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "MemoryDevice.h"
#include <AK/Memory.h>
#include <AK/StdLibExtras.h>
#include <Kernel/Arch/PC/BIOS.h>
#include <Kernel/VM/AnonymousVMObject.h>
#include <Kernel/VM/TypedMapping.h>
namespace Kernel {
MemoryDevice::MemoryDevice()
: CharacterDevice(1, 1)
{
}
MemoryDevice::~MemoryDevice()
{
}
KResultOr<size_t> MemoryDevice::read(FileDescription&, size_t, UserOrKernelBuffer&, size_t)
{
TODO();
}
void MemoryDevice::did_seek(FileDescription&, off_t)
{
TODO();
}
KResultOr<Region*> MemoryDevice::mmap(Process& process, FileDescription&, const Range& range, size_t offset, int prot, bool shared)
{
auto viewed_address = PhysicalAddress(offset);
dbgln("MemoryDevice: Trying to mmap physical memory at {} for range of {} bytes", viewed_address, range.size());
if (!MM.is_allowed_to_mmap_to_userspace(viewed_address, range)) {
dbgln("MemoryDevice: Trying to mmap physical memory at {} for range of {} bytes failed due to violation of access", viewed_address, range.size());
return EINVAL;
}
auto vmobject = AnonymousVMObject::create_for_physical_range(viewed_address, range.size());
if (!vmobject)
return ENOMEM;
dbgln("MemoryDevice: Mapped physical memory at {} for range of {} bytes", viewed_address, range.size());
return process.allocate_region_with_vmobject(
range,
vmobject.release_nonnull(),
0,
"Mapped Physical Memory",
prot,
shared);
}
}