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);
+	};
+
+}

kernel/include/kernel/Memory/MemoryRegion.h

@@ -0,0 +1,59 @@
+#pragma once
+
+#include <BAN/UniqPtr.h>
+#include <kernel/Memory/PageTable.h>
+#include <kernel/Memory/Types.h>
+
+#include <stddef.h>
+
+namespace Kernel
+{
+
+	struct AddressRange
+	{
+		vaddr_t start;
+		vaddr_t end;
+	};
+
+	class MemoryRegion
+	{
+		BAN_NON_COPYABLE(MemoryRegion);
+		BAN_NON_MOVABLE(MemoryRegion);
+
+	public:
+		enum Type : uint8_t
+		{
+			PRIVATE,
+			SHARED
+		};
+
+	public:
+		virtual ~MemoryRegion();
+
+		bool contains(vaddr_t address) const;
+		bool contains_fully(vaddr_t address, size_t size) const;
+		bool overlaps(vaddr_t address, size_t size) const;
+
+		size_t size() const { return m_size; }
+		vaddr_t vaddr() const { return m_vaddr; }
+
+		// Returns error if no memory was available
+		// Returns true if page was succesfully allocated
+		// Returns false if page was already allocated
+		virtual BAN::ErrorOr<bool> allocate_page_containing(vaddr_t address) = 0;
+
+		virtual BAN::ErrorOr<BAN::UniqPtr<MemoryRegion>> clone(PageTable& new_page_table) = 0;
+	
+	protected:
+		MemoryRegion(PageTable&, size_t size, Type type, PageTable::flags_t flags);
+		BAN::ErrorOr<void> initialize(AddressRange);
+
+	protected:
+		PageTable& m_page_table;
+		const size_t m_size;
+		const Type m_type;
+		const PageTable::flags_t m_flags;
+		vaddr_t m_vaddr { 0 };
+	};
+
+}

kernel/include/kernel/Process.h

@@ -7,7 +7,7 @@
 #include <kernel/Credentials.h>
 #include <kernel/FS/Inode.h>
 #include <kernel/Memory/Heap.h>
-#include <kernel/Memory/VirtualRange.h>
+#include <kernel/Memory/MemoryRegion.h>
 #include <kernel/OpenFileDescriptorSet.h>
 #include <kernel/SpinLock.h>
 #include <kernel/Terminal/TTY.h>
@@ -174,7 +174,7 @@ namespace Kernel
 		OpenFileDescriptorSet m_open_file_descriptors;
 
 		BAN::UniqPtr<LibELF::LoadableELF> m_loadable_elf;
-		BAN::Vector<BAN::UniqPtr<VirtualRange>> m_mapped_ranges;
+		BAN::Vector<BAN::UniqPtr<MemoryRegion>> m_mapped_regions;
 
 		pid_t m_sid;
 		pid_t m_pgrp;