diff options
Diffstat (limited to 'src/core/hle/kernel/memory/page_heap.cpp')
-rw-r--r-- | src/core/hle/kernel/memory/page_heap.cpp | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/src/core/hle/kernel/memory/page_heap.cpp b/src/core/hle/kernel/memory/page_heap.cpp new file mode 100644 index 000000000..efcbb3cad --- /dev/null +++ b/src/core/hle/kernel/memory/page_heap.cpp @@ -0,0 +1,119 @@ +// 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 Atmosphère, an open-source firmware for +// the Nintendo Switch. Copyright 2018-2020 Atmosphère-NX. + +#include "core/core.h" +#include "core/hle/kernel/memory/page_heap.h" +#include "core/memory.h" + +namespace Kernel::Memory { + +void PageHeap::Initialize(VAddr address, std::size_t size, std::size_t metadata_size) { + // Check our assumptions + ASSERT(Common::IsAligned((address), PageSize)); + ASSERT(Common::IsAligned(size, PageSize)); + + // Set our members + heap_address = address; + heap_size = size; + + // Setup bitmaps + metadata.resize(metadata_size / sizeof(u64)); + u64* cur_bitmap_storage{metadata.data()}; + for (std::size_t i = 0; i < MemoryBlockPageShifts.size(); i++) { + const std::size_t cur_block_shift{MemoryBlockPageShifts[i]}; + const std::size_t next_block_shift{ + (i != MemoryBlockPageShifts.size() - 1) ? MemoryBlockPageShifts[i + 1] : 0}; + cur_bitmap_storage = blocks[i].Initialize(heap_address, heap_size, cur_block_shift, + next_block_shift, cur_bitmap_storage); + } +} + +VAddr PageHeap::AllocateBlock(s32 index) { + const std::size_t needed_size{blocks[index].GetSize()}; + + for (s32 i{index}; i < static_cast<s32>(MemoryBlockPageShifts.size()); i++) { + if (const VAddr addr{blocks[i].PopBlock()}; addr) { + if (const std::size_t allocated_size{blocks[i].GetSize()}; + allocated_size > needed_size) { + Free(addr + needed_size, (allocated_size - needed_size) / PageSize); + } + return addr; + } + } + + return 0; +} + +void PageHeap::FreeBlock(VAddr block, s32 index) { + do { + block = blocks[index++].PushBlock(block); + } while (block != 0); +} + +void PageHeap::Free(VAddr addr, std::size_t num_pages) { + // Freeing no pages is a no-op + if (num_pages == 0) { + return; + } + + // Find the largest block size that we can free, and free as many as possible + s32 big_index{static_cast<s32>(MemoryBlockPageShifts.size()) - 1}; + const VAddr start{addr}; + const VAddr end{(num_pages * PageSize) + addr}; + VAddr before_start{start}; + VAddr before_end{start}; + VAddr after_start{end}; + VAddr after_end{end}; + while (big_index >= 0) { + const std::size_t block_size{blocks[big_index].GetSize()}; + const VAddr big_start{Common::AlignUp((start), block_size)}; + const VAddr big_end{Common::AlignDown((end), block_size)}; + if (big_start < big_end) { + // Free as many big blocks as we can + for (auto block{big_start}; block < big_end; block += block_size) { + FreeBlock(block, big_index); + } + before_end = big_start; + after_start = big_end; + break; + } + big_index--; + } + ASSERT(big_index >= 0); + + // Free space before the big blocks + for (s32 i{big_index - 1}; i >= 0; i--) { + const std::size_t block_size{blocks[i].GetSize()}; + while (before_start + block_size <= before_end) { + before_end -= block_size; + FreeBlock(before_end, i); + } + } + + // Free space after the big blocks + for (s32 i{big_index - 1}; i >= 0; i--) { + const std::size_t block_size{blocks[i].GetSize()}; + while (after_start + block_size <= after_end) { + FreeBlock(after_start, i); + after_start += block_size; + } + } +} + +std::size_t PageHeap::CalculateMetadataOverheadSize(std::size_t region_size) { + std::size_t overhead_size = 0; + for (std::size_t i = 0; i < MemoryBlockPageShifts.size(); i++) { + const std::size_t cur_block_shift{MemoryBlockPageShifts[i]}; + const std::size_t next_block_shift{ + (i != MemoryBlockPageShifts.size() - 1) ? MemoryBlockPageShifts[i + 1] : 0}; + overhead_size += PageHeap::Block::CalculateMetadataOverheadSize( + region_size, cur_block_shift, next_block_shift); + } + return Common::AlignUp(overhead_size, PageSize); +} + +} // namespace Kernel::Memory |