Kernel/LibC: Implement very basic msync

kernel/include/kernel/Memory/FileBackedRegion.h

@@ -10,6 +10,8 @@ namespace Kernel
 	{
 		~SharedFileData();
 
+		void sync(size_t page_index);
+
 		// FIXME: this should probably be ordered tree like map
 		//        for fast lookup and less memory usage
 		BAN::Vector<paddr_t> pages;
@@ -26,6 +28,8 @@ namespace Kernel
 		static BAN::ErrorOr<BAN::UniqPtr<FileBackedRegion>> create(BAN::RefPtr<Inode>, PageTable&, off_t offset, size_t size, AddressRange address_range, Type, PageTable::flags_t);
 		~FileBackedRegion();
 
+		virtual BAN::ErrorOr<void> msync(vaddr_t, size_t, int) override;
+
 		virtual BAN::ErrorOr<BAN::UniqPtr<MemoryRegion>> clone(PageTable& new_page_table) override;
 
 	protected:

kernel/include/kernel/Memory/MemoryBackedRegion.h

@@ -14,9 +14,10 @@ namespace Kernel
 		static BAN::ErrorOr<BAN::UniqPtr<MemoryBackedRegion>> create(PageTable&, size_t size, AddressRange, Type, PageTable::flags_t);
 		~MemoryBackedRegion();
 
-
 		virtual BAN::ErrorOr<BAN::UniqPtr<MemoryRegion>> clone(PageTable& new_page_table) override;
 
+		virtual BAN::ErrorOr<void> msync(vaddr_t, size_t, int) override { return {}; }
+
 		// 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);

kernel/include/kernel/Memory/MemoryRegion.h

@@ -40,6 +40,8 @@ namespace Kernel
 		size_t virtual_page_count() const { return BAN::Math::div_round_up<size_t>(m_size, PAGE_SIZE); }
 		size_t physical_page_count() const { return m_physical_page_count; }
 
+		virtual BAN::ErrorOr<void> msync(vaddr_t, size_t, int) = 0;
+
 		// Returns error if no memory was available
 		// Returns true if page was succesfully allocated
 		// Returns false if page was already allocated

kernel/include/kernel/Process.h

@@ -130,6 +130,7 @@ namespace Kernel
 
 		BAN::ErrorOr<long> sys_mmap(const sys_mmap_t*);
 		BAN::ErrorOr<long> sys_munmap(void* addr, size_t len);
+		BAN::ErrorOr<long> sys_msync(void* addr, size_t len, int flags);
 
 		BAN::ErrorOr<long> sys_tty_ctrl(int fildes, int command, int flags);