// Copyright 2020 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
// This file references various implementation details from Atmosphere, an open-source firmware for
// the Nintendo Switch. Copyright 2018-2020 Atmosphere-NX.
#pragma once
#include <array>
#include <bit>
#include <vector>
#include "common/alignment.h"
#include "common/assert.h"
#include "common/common_funcs.h"
#include "common/common_types.h"
#include "core/hle/kernel/k_page_bitmap.h"
#include "core/hle/kernel/memory/memory_types.h"
namespace Kernel::Memory {
class PageHeap final : NonCopyable {
public:
static constexpr s32 GetAlignedBlockIndex(std::size_t num_pages, std::size_t align_pages) {
const auto target_pages{std::max(num_pages, align_pages)};
for (std::size_t i = 0; i < NumMemoryBlockPageShifts; i++) {
if (target_pages <=
(static_cast<std::size_t>(1) << MemoryBlockPageShifts[i]) / PageSize) {
return static_cast<s32>(i);
}
}
return -1;
}
static constexpr s32 GetBlockIndex(std::size_t num_pages) {
for (s32 i{static_cast<s32>(NumMemoryBlockPageShifts) - 1}; i >= 0; i--) {
if (num_pages >= (static_cast<std::size_t>(1) << MemoryBlockPageShifts[i]) / PageSize) {
return i;
}
}
return -1;
}
static constexpr std::size_t GetBlockSize(std::size_t index) {
return static_cast<std::size_t>(1) << MemoryBlockPageShifts[index];
}
static constexpr std::size_t GetBlockNumPages(std::size_t index) {
return GetBlockSize(index) / PageSize;
}
private:
static constexpr std::size_t NumMemoryBlockPageShifts{7};
static constexpr std::array<std::size_t, NumMemoryBlockPageShifts> MemoryBlockPageShifts{
0xC, 0x10, 0x15, 0x16, 0x19, 0x1D, 0x1E,
};
class Block final : NonCopyable {
private:
KPageBitmap bitmap;
VAddr heap_address{};
uintptr_t end_offset{};
std::size_t block_shift{};
std::size_t next_block_shift{};
public:
Block() = default;
constexpr std::size_t GetShift() const {
return block_shift;
}
constexpr std::size_t GetNextShift() const {
return next_block_shift;
}
constexpr std::size_t GetSize() const {
return static_cast<std::size_t>(1) << GetShift();
}
constexpr std::size_t GetNumPages() const {
return GetSize() / PageSize;
}
constexpr std::size_t GetNumFreeBlocks() const {
return bitmap.GetNumBits();
}
constexpr std::size_t GetNumFreePages() const {
return GetNumFreeBlocks() * GetNumPages();
}
u64* Initialize(VAddr addr, std::size_t size, std::size_t bs, std::size_t nbs,
u64* bit_storage) {
// Set shifts
block_shift = bs;
next_block_shift = nbs;
// Align up the address
VAddr end{addr + size};
const auto align{(next_block_shift != 0) ? (1ULL << next_block_shift)
: (1ULL << block_shift)};
addr = Common::AlignDown((addr), align);
end = Common::AlignUp((end), align);
heap_address = addr;
end_offset = (end - addr) / (1ULL << block_shift);
return bitmap.Initialize(bit_storage, end_offset);
}
VAddr PushBlock(VAddr address) {
// Set the bit for the free block
std::size_t offset{(address - heap_address) >> GetShift()};
bitmap.SetBit(offset);
// If we have a next shift, try to clear the blocks below and return the address
if (GetNextShift()) {
const auto diff{1ULL << (GetNextShift() - GetShift())};
offset = Common::AlignDown(offset, diff);
if (bitmap.ClearRange(offset, diff)) {
return heap_address + (offset << GetShift());
}
}
// We couldn't coalesce, or we're already as big as possible
return 0;
}
VAddr PopBlock(bool random) {
// Find a free block
const s64 soffset{bitmap.FindFreeBlock(random)};
if (soffset < 0) {
return 0;
}
const auto offset{static_cast<std::size_t>(soffset)};
// Update our tracking and return it
bitmap.ClearBit(offset);
return heap_address + (offset << GetShift());
}
public:
static constexpr std::size_t CalculateManagementOverheadSize(std::size_t region_size,
std::size_t cur_block_shift,
std::size_t next_block_shift) {
const auto cur_block_size{(1ULL << cur_block_shift)};
const auto next_block_size{(1ULL << next_block_shift)};
const auto align{(next_block_shift != 0) ? next_block_size : cur_block_size};
return KPageBitmap::CalculateManagementOverheadSize(
(align * 2 + Common::AlignUp(region_size, align)) / cur_block_size);
}
};
public:
PageHeap() = default;
constexpr VAddr GetAddress() const {
return heap_address;
}
constexpr std::size_t GetSize() const {
return heap_size;
}
constexpr VAddr GetEndAddress() const {
return GetAddress() + GetSize();
}
constexpr std::size_t GetPageOffset(VAddr block) const {
return (block - GetAddress()) / PageSize;
}
void Initialize(VAddr heap_address, std::size_t heap_size, std::size_t metadata_size);
VAddr AllocateBlock(s32 index, bool random);
void Free(VAddr addr, std::size_t num_pages);
void UpdateUsedSize() {
used_size = heap_size - (GetNumFreePages() * PageSize);
}
static std::size_t CalculateManagementOverheadSize(std::size_t region_size);
private:
constexpr std::size_t GetNumFreePages() const {
std::size_t num_free{};
for (const auto& block : blocks) {
num_free += block.GetNumFreePages();
}
return num_free;
}
void FreeBlock(VAddr block, s32 index);
VAddr heap_address{};
std::size_t heap_size{};
std::size_t used_size{};
std::array<Block, NumMemoryBlockPageShifts> blocks{};
std::vector<u64> metadata;
};
} // namespace Kernel::Memory