Cleanup Redox repo, update Rust, remove old target

kernel/arch/x86_64/src/paging/temporary_page.rs

@@ -0,0 +1,45 @@
+//! Temporarily map a page
+//! From [Phil Opp's Blog](http://os.phil-opp.com/remap-the-kernel.html)
+
+use memory::Frame;
+
+use super::{ActivePageTable, Page, VirtualAddress};
+use super::entry::EntryFlags;
+use super::table::{Table, Level1};
+
+pub struct TemporaryPage {
+    page: Page,
+}
+
+impl TemporaryPage {
+    pub fn new(page: Page) -> TemporaryPage {
+        TemporaryPage {
+            page: page,
+        }
+    }
+
+    pub fn start_address (&self) -> VirtualAddress {
+        self.page.start_address()
+    }
+
+    /// Maps the temporary page to the given frame in the active table.
+    /// Returns the start address of the temporary page.
+    pub fn map(&mut self, frame: Frame, flags: EntryFlags, active_table: &mut ActivePageTable) -> VirtualAddress {
+        assert!(active_table.translate_page(self.page).is_none(), "temporary page is already mapped");
+        let result = active_table.map_to(self.page, frame, flags);
+        result.flush(active_table);
+        self.page.start_address()
+    }
+
+    /// Maps the temporary page to the given page table frame in the active
+    /// table. Returns a reference to the now mapped table.
+    pub fn map_table_frame(&mut self, frame: Frame, flags: EntryFlags, active_table: &mut ActivePageTable) -> &mut Table<Level1> {
+        unsafe { &mut *(self.map(frame, flags, active_table).get() as *mut Table<Level1>) }
+    }
+
+    /// Unmaps the temporary page in the active table.
+    pub fn unmap(&mut self, active_table: &mut ActivePageTable) {
+        let result = active_table.unmap(self.page);
+        result.flush(active_table);
+    }
+}