mirror of
https://github.com/Atmosphere-NX/Atmosphere.git
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60 lines
2.8 KiB
C++
60 lines
2.8 KiB
C++
/*
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* Copyright (c) 2018-2020 Atmosphère-NX
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <vapours.hpp>
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namespace ams::kern {
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class KPageHeap {
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private:
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class Block {
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private:
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class Bitmap {
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/* TODO: This is a four-level bitmap tracking page usage. */
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private:
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static constexpr s32 GetRequiredDepth(size_t region_size) {
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s32 depth = 0;
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while (true) {
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region_size /= BITSIZEOF(u64);
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depth++;
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if (region_size == 0) {
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return depth;
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}
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}
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}
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public:
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static constexpr size_t CalculateMetadataOverheadSize(size_t region_size) {
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size_t overhead_bits = 0;
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for (s32 depth = GetRequiredDepth(region_size) - 1; depth >= 0; depth--) {
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region_size = util::AlignUp(region_size, BITSIZEOF(u64)) / BITSIZEOF(u64);
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overhead_bits += region_size;
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}
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return overhead_bits * sizeof(u64);
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}
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};
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public:
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static constexpr size_t CalculateMetadataOverheadSize(size_t region_size, size_t cur_block_shift, size_t next_block_shift) {
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const size_t cur_block_size = (1ul << cur_block_shift);
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const size_t next_block_size = (1ul << next_block_shift);
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const size_t align = (next_block_shift != 0) ? next_block_size : cur_block_size;
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return Bitmap::CalculateMetadataOverheadSize((align * 2 + util::AlignUp(region_size, align)) / cur_block_size);
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}
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};
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public:
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static size_t CalculateMetadataOverheadSize(size_t region_size, const size_t *block_shifts, size_t num_block_shifts);
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};
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}
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