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f614f0e2cb
There was a frequently occurring pattern of "map this physical address into kernel VM, then read from it, then unmap it again". This new typed_map() encapsulates that logic by giving you back a typed pointer to the kind of structure you're interested in accessing. It returns a TypedMapping<T> that can be used mostly like a pointer. When destroyed, the TypedMapping object will unmap the memory. :^)
67 lines
2.5 KiB
C++
67 lines
2.5 KiB
C++
/*
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* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include <AK/StringView.h>
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#include <Kernel/VM/MemoryManager.h>
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namespace Kernel {
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template<typename T>
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struct TypedMapping {
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const T* ptr() const { return reinterpret_cast<const T*>(region->vaddr().offset(offset).as_ptr()); }
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T* ptr() { return reinterpret_cast<T*>(region->vaddr().offset(offset).as_ptr()); }
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const T* operator->() const { return ptr(); }
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const T& operator*() const { return *ptr(); }
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T& operator*() { return *ptr(); }
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OwnPtr<Region> region;
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size_t offset { 0 };
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};
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template<typename T>
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static TypedMapping<T> map_typed(PhysicalAddress paddr, size_t length, u8 access = Region::Access::Read)
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{
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TypedMapping<T> table;
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table.region = MM.allocate_kernel_region(paddr.page_base(), PAGE_ROUND_UP(length), {}, access);
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table.offset = paddr.offset_in_page();
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return table;
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}
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template<typename T>
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static TypedMapping<T> map_typed(PhysicalAddress paddr)
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{
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return map_typed<T>(paddr, sizeof(T));
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}
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template<typename T>
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static TypedMapping<T> map_typed_writable(PhysicalAddress paddr)
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{
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return map_typed<T>(paddr, sizeof(T), Region::Access::Read | Region::Access::Write);
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}
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}
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