Create TSS and GDT modules and use a double fault stack

src/memory/paging/mod.rs

@@ -11,7 +11,7 @@ pub use self::entry::*;
 use memory::{PAGE_SIZE, Frame, FrameAllocator};
 use self::temporary_page::TemporaryPage;
 pub use self::mapper::Mapper;
-use core::ops::{Deref, DerefMut};
+use core::ops::{Deref, DerefMut, Add};
 use multiboot2::BootInformation;
 
 mod entry;
@@ -37,7 +37,7 @@ impl Page {
         Page { number: address / PAGE_SIZE }
     }
 
-    fn start_address(&self) -> usize {
+    pub fn start_address(&self) -> usize {
         self.number * PAGE_SIZE
     }
 
@@ -62,6 +62,14 @@ impl Page {
     }
 }
 
+impl Add<usize> for Page {
+    type Output = Page;
+
+    fn add(self, rhs: usize) -> Page {
+        Page { number: self.number + rhs }
+    }
+}
+
 pub struct PageIter {
     start: Page,
     end: Page,