ladybird/Kernel/Devices/MemoryDevice.cpp
Liav A aee4786d8e Kernel: Introduce the DeviceManagement singleton
This singleton simplifies many aspects that we struggled with before:
1. There's no need to make derived classes of Device expose the
constructor as public anymore. The singleton is a friend of them, so he
can call the constructor. This solves the issue with try_create_device
helper neatly, hopefully for good.
2. Getting a reference of the NullDevice is now being done from this
singleton, which means that NullDevice no longer needs to use its own
singleton, and we can apply the try_create_device helper on it too :)
3. We can now defer registration completely after the Device constructor
which means the Device constructor is merely assigning the major and
minor numbers of the Device, and the try_create_device helper ensures it
calls the after_inserting method immediately after construction. This
creates a great opportunity to make registration more OOM-safe.
2021-09-17 01:02:48 +03:00

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/*
* Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Memory.h>
#include <AK/StdLibExtras.h>
#include <Kernel/Devices/DeviceManagement.h>
#include <Kernel/Devices/MemoryDevice.h>
#include <Kernel/Firmware/BIOS.h>
#include <Kernel/Memory/AnonymousVMObject.h>
#include <Kernel/Sections.h>
namespace Kernel {
UNMAP_AFTER_INIT NonnullRefPtr<MemoryDevice> MemoryDevice::must_create()
{
auto memory_device_or_error = DeviceManagement::try_create_device<MemoryDevice>();
// FIXME: Find a way to propagate errors
VERIFY(!memory_device_or_error.is_error());
return memory_device_or_error.release_value();
}
UNMAP_AFTER_INIT MemoryDevice::MemoryDevice()
: CharacterDevice(1, 1)
{
}
UNMAP_AFTER_INIT MemoryDevice::~MemoryDevice()
{
}
KResultOr<size_t> MemoryDevice::read(OpenFileDescription&, u64, UserOrKernelBuffer&, size_t)
{
TODO();
}
void MemoryDevice::did_seek(OpenFileDescription&, off_t)
{
TODO();
}
KResultOr<Memory::Region*> MemoryDevice::mmap(Process& process, OpenFileDescription&, Memory::VirtualRange const& range, u64 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 = TRY(Memory::AnonymousVMObject::try_create_for_physical_range(viewed_address, range.size()));
dbgln("MemoryDevice: Mapped physical memory at {} for range of {} bytes", viewed_address, range.size());
return process.address_space().allocate_region_with_vmobject(
range,
move(vmobject),
0,
"Mapped Physical Memory",
prot,
shared);
}
}