ladybird/Kernel/VM/TypedMapping.h
Andreas Kling 09b1b09c19 Kernel: Assert if rounding-up-to-page-size would wrap around to 0
If we try to align a number above 0xfffff000 to the next multiple of
the page size (4 KiB), it would wrap around to 0. This is most likely
never what we want, so let's assert if that happens.
2021-02-14 10:01:50 +01:00

68 lines
2.5 KiB
C++

/*
* 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
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* 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(); }
T* operator->() { 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);
}
}