mirror of
https://github.com/Atmosphere-NX/Atmosphere
synced 2024-12-23 12:51:13 +00:00
108 lines
3.7 KiB
C++
108 lines
3.7 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_slab_helpers.hpp>
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#include <mesosphere/kern_k_dynamic_slab_heap.hpp>
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namespace ams::kern {
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namespace impl {
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class PageTablePage {
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private:
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u8 buffer[PageSize];
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};
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static_assert(sizeof(PageTablePage) == PageSize);
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}
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class KPageTableManager : public KDynamicSlabHeap<impl::PageTablePage> {
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public:
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using RefCount = u16;
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static constexpr size_t PageTableSize = sizeof(impl::PageTablePage);
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static_assert(PageTableSize == PageSize);
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private:
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using BaseHeap = KDynamicSlabHeap<impl::PageTablePage>;
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private:
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RefCount *ref_counts;
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public:
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static constexpr size_t CalculateReferenceCountSize(size_t size) {
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return (size / PageSize) * sizeof(RefCount);
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}
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public:
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constexpr KPageTableManager() : BaseHeap(), ref_counts() { /* ... */ }
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private:
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void Initialize(RefCount *rc) {
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this->ref_counts = rc;
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for (size_t i = 0; i < this->GetSize() / PageSize; i++) {
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this->ref_counts[i] = 0;
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}
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}
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constexpr RefCount *GetRefCountPointer(KVirtualAddress addr) const {
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return std::addressof(this->ref_counts[(addr - this->GetAddress()) / PageSize]);
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}
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public:
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void Initialize(KDynamicPageManager *next_allocator, RefCount *rc) {
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BaseHeap::Initialize(next_allocator);
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this->Initialize(rc);
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}
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void Initialize(KVirtualAddress memory, size_t sz, RefCount *rc) {
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BaseHeap::Initialize(memory, sz);
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this->Initialize(rc);
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}
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KVirtualAddress Allocate() {
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return KVirtualAddress(BaseHeap::Allocate());
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}
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void Free(KVirtualAddress addr) {
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/* Ensure all pages in the heap are zero. */
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cpu::ClearPageToZero(GetVoidPointer(addr));
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/* Free the page. */
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BaseHeap::Free(GetPointer<impl::PageTablePage>(addr));
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}
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RefCount GetRefCount(KVirtualAddress addr) const {
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MESOSPHERE_ASSERT(this->IsInRange(addr));
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return *this->GetRefCountPointer(addr);
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}
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void Open(KVirtualAddress addr, int count) {
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MESOSPHERE_ASSERT(this->IsInRange(addr));
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*this->GetRefCountPointer(addr) += count;
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MESOSPHERE_ABORT_UNLESS(this->GetRefCount(addr) > 0);
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}
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bool Close(KVirtualAddress addr, int count) {
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MESOSPHERE_ASSERT(this->IsInRange(addr));
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MESOSPHERE_ABORT_UNLESS(this->GetRefCount(addr) >= count);
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*this->GetRefCountPointer(addr) -= count;
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return this->GetRefCount(addr) == 0;
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}
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constexpr bool IsInPageTableHeap(KVirtualAddress addr) const {
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return this->IsInRange(addr);
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}
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};
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}
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