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ca254699ec
So far we only had mmap(2) functionality on the /dev/mem device, but now we can also do read(2) on it. The test unit was updated to check we are doing it safely.
70 lines
2.4 KiB
C++
70 lines
2.4 KiB
C++
/*
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* Copyright (c) 2021, Liav A. <liavalb@hotmail.co.il>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Memory.h>
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#include <AK/StdLibExtras.h>
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#include <Kernel/Devices/DeviceManagement.h>
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#include <Kernel/Devices/MemoryDevice.h>
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#include <Kernel/Firmware/BIOS.h>
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#include <Kernel/Memory/AnonymousVMObject.h>
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#include <Kernel/Memory/TypedMapping.h>
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#include <Kernel/Sections.h>
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namespace Kernel {
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UNMAP_AFTER_INIT NonnullRefPtr<MemoryDevice> MemoryDevice::must_create()
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{
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auto memory_device_or_error = DeviceManagement::try_create_device<MemoryDevice>();
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// FIXME: Find a way to propagate errors
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VERIFY(!memory_device_or_error.is_error());
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return memory_device_or_error.release_value();
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}
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UNMAP_AFTER_INIT MemoryDevice::MemoryDevice()
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: CharacterDevice(1, 1)
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{
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}
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UNMAP_AFTER_INIT MemoryDevice::~MemoryDevice()
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{
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}
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ErrorOr<size_t> MemoryDevice::read(OpenFileDescription&, u64 offset, UserOrKernelBuffer& buffer, size_t length)
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{
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if (!MM.is_allowed_to_read_physical_memory_for_userspace(PhysicalAddress(offset), length)) {
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dbgln("MemoryDevice: Trying to read physical memory at {} for range of {} bytes failed due to violation of access", PhysicalAddress(offset), length);
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return EINVAL;
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}
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auto mapping = Memory::map_typed<u8>(PhysicalAddress(offset), length);
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auto bytes = ReadonlyBytes { mapping.ptr(), length };
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TRY(buffer.write(bytes));
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return length;
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}
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ErrorOr<Memory::Region*> MemoryDevice::mmap(Process& process, OpenFileDescription&, Memory::VirtualRange const& range, u64 offset, int prot, bool shared)
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{
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auto viewed_address = PhysicalAddress(offset);
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dbgln("MemoryDevice: Trying to mmap physical memory at {} for range of {} bytes", viewed_address, range.size());
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if (!MM.is_allowed_to_read_physical_memory_for_userspace(viewed_address, range.size())) {
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dbgln("MemoryDevice: Trying to mmap physical memory at {} for range of {} bytes failed due to violation of access", viewed_address, range.size());
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return EINVAL;
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}
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auto vmobject = TRY(Memory::AnonymousVMObject::try_create_for_physical_range(viewed_address, range.size()));
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dbgln("MemoryDevice: Mapped physical memory at {} for range of {} bytes", viewed_address, range.size());
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return process.address_space().allocate_region_with_vmobject(
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range,
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move(vmobject),
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0,
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"Mapped Physical Memory",
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prot,
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shared);
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}
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}
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