From b4fc2e52a2d51f8958b77fbe4fb76c854cd4593b Mon Sep 17 00:00:00 2001
From: bunnei <bunneidev@gmail.com>
Date: Thu, 20 May 2021 18:15:59 -0700
Subject: hle: kernel: Use host memory allocations for KSlabMemory.

- There are some issues with the current workaround, we will just use host memory until we have a complete kernel memory implementation.
---
 src/core/hle/kernel/k_slab_heap.h | 154 +++-----------------------------------
 1 file changed, 11 insertions(+), 143 deletions(-)

(limited to 'src/core/hle/kernel/k_slab_heap.h')

diff --git a/src/core/hle/kernel/k_slab_heap.h b/src/core/hle/kernel/k_slab_heap.h
index 5ce9a1d7c..81d472a3e 100644
--- a/src/core/hle/kernel/k_slab_heap.h
+++ b/src/core/hle/kernel/k_slab_heap.h
@@ -4,165 +4,33 @@
 
 #pragma once
 
-#include <atomic>
-
-#include "common/assert.h"
-#include "common/common_types.h"
-
 namespace Kernel {
 
-namespace impl {
-
-class KSlabHeapImpl final : NonCopyable {
-public:
-    struct Node {
-        Node* next{};
-    };
-
-    constexpr KSlabHeapImpl() = default;
-
-    void Initialize(std::size_t size) {
-        ASSERT(head == nullptr);
-        obj_size = size;
-    }
-
-    constexpr std::size_t GetObjectSize() const {
-        return obj_size;
-    }
-
-    Node* GetHead() const {
-        return head;
-    }
-
-    void* Allocate() {
-        Node* ret = head.load();
-
-        do {
-            if (ret == nullptr) {
-                break;
-            }
-        } while (!head.compare_exchange_weak(ret, ret->next));
-
-        return ret;
-    }
-
-    void Free(void* obj) {
-        Node* node = static_cast<Node*>(obj);
-
-        Node* cur_head = head.load();
-        do {
-            node->next = cur_head;
-        } while (!head.compare_exchange_weak(cur_head, node));
-    }
-
-private:
-    std::atomic<Node*> head{};
-    std::size_t obj_size{};
-};
-
-} // namespace impl
-
-class KSlabHeapBase : NonCopyable {
-public:
-    constexpr KSlabHeapBase() = default;
-
-    constexpr bool Contains(uintptr_t addr) const {
-        return start <= addr && addr < end;
-    }
-
-    constexpr std::size_t GetSlabHeapSize() const {
-        return (end - start) / GetObjectSize();
-    }
-
-    constexpr std::size_t GetObjectSize() const {
-        return impl.GetObjectSize();
-    }
+class KernelCore;
 
-    constexpr uintptr_t GetSlabHeapAddress() const {
-        return start;
-    }
-
-    std::size_t GetObjectIndexImpl(const void* obj) const {
-        return (reinterpret_cast<uintptr_t>(obj) - start) / GetObjectSize();
-    }
-
-    std::size_t GetPeakIndex() const {
-        return GetObjectIndexImpl(reinterpret_cast<const void*>(peak));
-    }
-
-    void* AllocateImpl() {
-        return impl.Allocate();
-    }
-
-    void FreeImpl(void* obj) {
-        // Don't allow freeing an object that wasn't allocated from this heap
-        ASSERT(Contains(reinterpret_cast<uintptr_t>(obj)));
-
-        impl.Free(obj);
-    }
-
-    void InitializeImpl(std::size_t obj_size, void* memory, std::size_t memory_size) {
-        // Ensure we don't initialize a slab using null memory
-        ASSERT(memory != nullptr);
-
-        // Initialize the base allocator
-        impl.Initialize(obj_size);
-
-        // Set our tracking variables
-        const std::size_t num_obj = (memory_size / obj_size);
-        start = reinterpret_cast<uintptr_t>(memory);
-        end = start + num_obj * obj_size;
-        peak = start;
-
-        // Free the objects
-        u8* cur = reinterpret_cast<u8*>(end);
-
-        for (std::size_t i{}; i < num_obj; i++) {
-            cur -= obj_size;
-            impl.Free(cur);
-        }
-    }
-
-private:
-    using Impl = impl::KSlabHeapImpl;
-
-    Impl impl;
-    uintptr_t peak{};
-    uintptr_t start{};
-    uintptr_t end{};
-};
+/// This is a placeholder class to manage slab heaps for kernel objects. For now, we just allocate
+/// these with new/delete, but this can be re-implemented later to allocate these in emulated
+/// memory.
 
 template <typename T>
-class KSlabHeap final : public KSlabHeapBase {
+class KSlabHeap final : NonCopyable {
 public:
-    constexpr KSlabHeap() : KSlabHeapBase() {}
+    KSlabHeap() = default;
 
-    void Initialize(void* memory, std::size_t memory_size) {
-        InitializeImpl(sizeof(T), memory, memory_size);
+    void Initialize([[maybe_unused]] void* memory, [[maybe_unused]] std::size_t memory_size) {
+        // Placeholder that should initialize the backing slab heap implementation.
     }
 
     T* Allocate() {
-        T* obj = static_cast<T*>(AllocateImpl());
-        if (obj != nullptr) {
-            new (obj) T();
-        }
-        return obj;
+        return new T();
     }
 
     T* AllocateWithKernel(KernelCore& kernel) {
-        T* obj = static_cast<T*>(AllocateImpl());
-        if (obj != nullptr) {
-            new (obj) T(kernel);
-        }
-        return obj;
+        return new T(kernel);
     }
 
     void Free(T* obj) {
-        FreeImpl(obj);
-    }
-
-    constexpr std::size_t GetObjectIndex(const T* obj) const {
-        return GetObjectIndexImpl(obj);
+        delete obj;
     }
 };
 
-- 
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