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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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61
Kernel/Devices/MemoryDevice.h 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.
*/
#pragma once
#include <AK/String.h>
#include <AK/Types.h>
#include <Kernel/Devices/CharacterDevice.h>
#include <Kernel/PhysicalAddress.h>
namespace Kernel {
class MemoryDevice final : public CharacterDevice {
AK_MAKE_ETERNAL
public:
MemoryDevice();
~MemoryDevice();
virtual KResultOr<Region*> mmap(Process&, FileDescription&, const Range&, size_t offset, int prot, bool shared) override;
// ^Device
virtual mode_t required_mode() const override { return 0660; }
virtual String device_name() const override { return "mem"; };
private:
virtual const char* class_name() const override { return "MemoryDevice"; }
virtual bool can_read(const FileDescription&, size_t) const override { return true; }
virtual bool can_write(const FileDescription&, size_t) const override { return false; }
virtual bool is_seekable() const { return true; }
virtual KResultOr<size_t> read(FileDescription&, size_t, UserOrKernelBuffer&, size_t) override;
virtual KResultOr<size_t> write(FileDescription&, size_t, const UserOrKernelBuffer&, size_t) override { return -EINVAL; }
virtual void did_seek(FileDescription&, off_t) override;
bool is_allowed_range(PhysicalAddress, const Range&) const;
};
}