Add clone methods to Page(public) and Frame(private)

src/memory/mod.rs

@@ -29,6 +29,10 @@ impl Frame {
     fn start_address(&self) -> PhysicalAddress {
         self.number * PAGE_SIZE
     }
+
+    fn clone(&self) -> Frame {
+        Frame { number: self.number }
+    }
 }
 
 pub trait FrameAllocator {

src/memory/paging/mod.rs

@@ -20,6 +20,7 @@ const ENTRY_COUNT: usize = 512;
 pub type PhysicalAddress = usize;
 pub type VirtualAddress = usize;
 
+#[derive(Debug, Clone, Copy)]
 pub struct Page {
     number: usize,
 }