Kernel: fork() now copies allocations through FixedWidthAllocator

kernel/include/kernel/Memory/FixedWidthAllocator.h

@@ -15,6 +15,8 @@ namespace Kernel
 		FixedWidthAllocator(MMU&, uint32_t);
 		~FixedWidthAllocator();
 
+		BAN::ErrorOr<FixedWidthAllocator*> clone(MMU&);
+
 		vaddr_t allocate();
 		bool deallocate(vaddr_t);
 
@@ -24,6 +26,8 @@ namespace Kernel
 		uint32_t max_allocations() const;
 
 	private:
+		bool allocate_page_if_needed(vaddr_t, uint8_t flags);
+
 		struct node
 		{
 			node* prev { nullptr };
@@ -34,6 +38,9 @@ namespace Kernel
 		node* node_from_address(vaddr_t) const;
 		void allocate_page_for_node_if_needed(const node*);
 
+		void allocate_node(node*);
+		void deallocate_node(node*);
+
 	private:
 		static constexpr uint32_t m_min_allocation_size = 16;