mirror of
https://github.com/Atmosphere-NX/Atmosphere
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116 lines
4.4 KiB
C++
116 lines
4.4 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 <mesosphere/kern_common.hpp>
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#include <mesosphere/kern_k_spin_lock.hpp>
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#include <mesosphere/kern_k_slab_heap.hpp>
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#include <mesosphere/kern_k_page_group.hpp>
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#include <mesosphere/kern_k_memory_block.hpp>
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#include <mesosphere/kern_k_page_bitmap.hpp>
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#include <mesosphere/kern_select_interrupt_manager.hpp>
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namespace ams::kern {
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class KDynamicPageManager {
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public:
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class PageBuffer {
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private:
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u8 buffer[PageSize];
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};
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static_assert(sizeof(PageBuffer) == PageSize);
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private:
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KSpinLock lock;
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KPageBitmap page_bitmap;
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size_t used;
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size_t peak;
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size_t count;
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KVirtualAddress address;
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size_t size;
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public:
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KDynamicPageManager() : lock(), page_bitmap(), used(), peak(), count(), address(), size() { /* ... */ }
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Result Initialize(KVirtualAddress memory, size_t sz) {
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/* We need to have positive size. */
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R_UNLESS(sz > 0, svc::ResultOutOfMemory());
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/* Calculate metadata overhead. */
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const size_t metadata_size = KPageBitmap::CalculateMetadataOverheadSize(sz / sizeof(PageBuffer));
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const size_t allocatable_size = sz - metadata_size;
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/* Set tracking fields. */
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this->address = memory;
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this->size = util::AlignDown(allocatable_size, sizeof(PageBuffer));
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this->count = allocatable_size / sizeof(PageBuffer);
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R_UNLESS(this->count > 0, svc::ResultOutOfMemory());
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/* Clear the metadata region. */
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u64 *metadata_ptr = GetPointer<u64>(this->address + allocatable_size);
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std::memset(metadata_ptr, 0, metadata_size);
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/* Initialize the bitmap. */
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this->page_bitmap.Initialize(metadata_ptr, this->count);
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/* Free the pages to the bitmap. */
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std::memset(GetPointer<PageBuffer>(this->address), 0, this->count * sizeof(PageBuffer));
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for (size_t i = 0; i < this->count; i++) {
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this->page_bitmap.SetBit(i);
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}
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return ResultSuccess();
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}
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constexpr KVirtualAddress GetAddress() const { return this->address; }
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constexpr size_t GetSize() const { return this->size; }
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constexpr size_t GetUsed() const { return this->used; }
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constexpr size_t GetPeak() const { return this->peak; }
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constexpr size_t GetCount() const { return this->count; }
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PageBuffer *Allocate() {
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/* Take the lock. */
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KScopedInterruptDisable di;
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KScopedSpinLock lk(this->lock);
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/* Find a random free block. */
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ssize_t soffset = this->page_bitmap.FindFreeBlock(true);
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if (AMS_UNLIKELY(soffset < 0)) {
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return nullptr;
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}
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const size_t offset = static_cast<size_t>(soffset);
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/* Update our tracking. */
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this->page_bitmap.ClearBit(offset);
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this->peak = std::max(this->peak, (++this->used));
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return GetPointer<PageBuffer>(this->address) + offset;
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}
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void Free(PageBuffer *pb) {
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/* Take the lock. */
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KScopedInterruptDisable di;
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KScopedSpinLock lk(this->lock);
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/* Set the bit for the free page. */
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size_t offset = (reinterpret_cast<uintptr_t>(pb) - GetInteger(this->address)) / sizeof(PageBuffer);
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this->page_bitmap.SetBit(offset);
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/* Decrement our used count. */
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--this->used;
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}
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};
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}
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