Kernel: Implement new abstract MemoryRegion

MemoryBackedRegion now inherits from this and is used for private
anonymous mappigs. This will make shared mappings and file backed
mappings much easier to implement.

kernel/include/kernel/Memory/MemoryBackedRegion.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <kernel/Memory/MemoryRegion.h>
+
+namespace Kernel
+{
+
+	class MemoryBackedRegion final : public MemoryRegion
+	{
+		BAN_NON_COPYABLE(MemoryBackedRegion);
+		BAN_NON_MOVABLE(MemoryBackedRegion);
+	
+	public:
+		static BAN::ErrorOr<BAN::UniqPtr<MemoryBackedRegion>> create(PageTable&, size_t size, AddressRange, Type, PageTable::flags_t);
+		~MemoryBackedRegion();
+
+		virtual BAN::ErrorOr<bool> allocate_page_containing(vaddr_t vaddr) override;
+
+		virtual BAN::ErrorOr<BAN::UniqPtr<MemoryRegion>> clone(PageTable& new_page_table) override;
+
+		// Copy data from buffer into this region
+		// This can fail if no memory is mapped and no free memory was available
+		BAN::ErrorOr<void> copy_data_to_region(size_t offset_into_region, const uint8_t* buffer, size_t buffer_size);
+
+	private:
+		MemoryBackedRegion(PageTable&, size_t size, Type, PageTable::flags_t);
+	};
+
+}