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Kernel: Add typed_map<T>(PhysicalAddress) and use it in ACPI parsing

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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. :^)
This commit is contained in:
Andreas Kling 2020-04-09 17:12:58 +02:00
parent 4644217094
commit f614f0e2cb
5 changed files with 140 additions and 98 deletions
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66
Kernel/VM/TypedMapping.h Normal file
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/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* 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/StringView.h>
#include <Kernel/VM/MemoryManager.h>
namespace Kernel {
template<typename T>
struct TypedMapping {
const T* ptr() const { return reinterpret_cast<const T*>(region->vaddr().offset(offset).as_ptr()); }
T* ptr() { return reinterpret_cast<T*>(region->vaddr().offset(offset).as_ptr()); }
const T* operator->() const { return ptr(); }
const T& operator*() const { return *ptr(); }
T& operator*() { return *ptr(); }
OwnPtr<Region> region;
size_t offset { 0 };
};
template<typename T>
static TypedMapping<T> map_typed(PhysicalAddress paddr, size_t length, u8 access = Region::Access::Read)
{
TypedMapping<T> table;
table.region = MM.allocate_kernel_region(paddr.page_base(), PAGE_ROUND_UP(length), {}, access);
table.offset = paddr.offset_in_page();
return table;
}
template<typename T>
static TypedMapping<T> map_typed(PhysicalAddress paddr)
{
return map_typed<T>(paddr, sizeof(T));
}
template<typename T>
static TypedMapping<T> map_typed_writable(PhysicalAddress paddr)
{
return map_typed<T>(paddr, sizeof(T), Region::Access::Read | Region::Access::Write);
}
}