Split mapping functions of ActivePageTable into mapper subtype

src/memory/paging/mapper.rs

@@ -0,0 +1,118 @@
+// Copyright 2015 Philipp Oppermann. See the README.md
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use super::{VirtualAddress, PhysicalAddress, Page, ENTRY_COUNT};
+use super::entry::*;
+use super::table::{self, Table, Level4, Level1};
+use memory::{PAGE_SIZE, Frame, FrameAllocator};
+use core::ptr::Unique;
+
+pub struct Mapper {
+    p4: Unique<Table<Level4>>,
+}
+
+impl Mapper {
+    pub unsafe fn new() -> Mapper {
+        Mapper { p4: Unique::new(table::P4) }
+    }
+
+    pub fn p4(&self) -> &Table<Level4> {
+        unsafe { self.p4.get() }
+    }
+
+    pub fn p4_mut(&mut self) -> &mut Table<Level4> {
+        unsafe { self.p4.get_mut() }
+    }
+
+    pub fn translate(&self, virtual_address: VirtualAddress) -> Option<PhysicalAddress> {
+        let offset = virtual_address % PAGE_SIZE;
+        self.translate_page(Page::containing_address(virtual_address))
+            .map(|frame| frame.number * PAGE_SIZE + offset)
+    }
+
+    pub fn translate_page(&self, page: Page) -> Option<Frame> {
+        let p3 = self.p4().next_table(page.p4_index());
+
+        let huge_page = || {
+            p3.and_then(|p3| {
+                let p3_entry = &p3[page.p3_index()];
+                // 1GiB page?
+                if let Some(start_frame) = p3_entry.pointed_frame() {
+                    if p3_entry.flags().contains(HUGE_PAGE) {
+                        // address must be 1GiB aligned
+                        assert!(start_frame.number % (ENTRY_COUNT * ENTRY_COUNT) == 0);
+                        return Some(Frame {
+                            number: start_frame.number + page.p2_index() * ENTRY_COUNT +
+                                    page.p1_index(),
+                        });
+                    }
+                }
+                if let Some(p2) = p3.next_table(page.p3_index()) {
+                    let p2_entry = &p2[page.p2_index()];
+                    // 2MiB page?
+                    if let Some(start_frame) = p2_entry.pointed_frame() {
+                        if p2_entry.flags().contains(HUGE_PAGE) {
+                            // address must be 2MiB aligned
+                            assert!(start_frame.number % ENTRY_COUNT == 0);
+                            return Some(Frame { number: start_frame.number + page.p1_index() });
+                        }
+                    }
+                }
+                None
+            })
+        };
+
+        p3.and_then(|p3| p3.next_table(page.p3_index()))
+          .and_then(|p2| p2.next_table(page.p2_index()))
+          .and_then(|p1| p1[page.p1_index()].pointed_frame())
+          .or_else(huge_page)
+    }
+
+    pub fn map_to<A>(&mut self, page: Page, frame: Frame, flags: EntryFlags, allocator: &mut A)
+        where A: FrameAllocator
+    {
+        let mut p3 = self.p4_mut().next_table_create(page.p4_index(), allocator);
+        let mut p2 = p3.next_table_create(page.p3_index(), allocator);
+        let mut p1 = p2.next_table_create(page.p2_index(), allocator);
+
+        assert!(p1[page.p1_index()].is_unused());
+        p1[page.p1_index()].set(frame, flags | PRESENT);
+    }
+
+    pub fn map<A>(&mut self, page: Page, flags: EntryFlags, allocator: &mut A)
+        where A: FrameAllocator
+    {
+        let frame = allocator.allocate_frame().expect("out of memory");
+        self.map_to(page, frame, flags, allocator)
+    }
+
+    pub fn identity_map<A>(&mut self, frame: Frame, flags: EntryFlags, allocator: &mut A)
+        where A: FrameAllocator
+    {
+        let page = Page::containing_address(frame.start_address());
+        self.map_to(page, frame, flags, allocator)
+    }
+
+    pub fn unmap<A>(&mut self, page: Page, allocator: &mut A)
+        where A: FrameAllocator
+    {
+        assert!(self.translate(page.start_address()).is_some());
+
+        let p1 = self.p4_mut()
+                     .next_table_mut(page.p4_index())
+                     .and_then(|p3| p3.next_table_mut(page.p3_index()))
+                     .and_then(|p2| p2.next_table_mut(page.p2_index()))
+                     .expect("mapping code does not support huge pages");
+        let frame = p1[page.p1_index()].pointed_frame().unwrap();
+        p1[page.p1_index()].set_unused();
+        unsafe { ::x86::tlb::flush(page.start_address()) };
+        // TODO free p(1,2,3) table if empty
+        // allocator.deallocate_frame(frame);
+    }
+}

src/memory/paging/mod.rs

@@ -11,11 +11,14 @@ pub use self::entry::*;
 use memory::{PAGE_SIZE, Frame, FrameAllocator};
 use self::table::{Table, Level4};
 use self::temporary_page::TemporaryPage;
+pub use self::mapper::Mapper;
+use core::ops::{Deref, DerefMut};
 use core::ptr::Unique;
 
 mod entry;
 mod table;
 mod temporary_page;
+mod mapper;
 
 const ENTRY_COUNT: usize = 512;
 
@@ -54,106 +57,26 @@ impl Page {
 }
 
 pub struct ActivePageTable {
-    p4: Unique<Table<Level4>>,
+    mapper: Mapper,
+}
+
+impl Deref for ActivePageTable {
+    type Target = Mapper;
+
+    fn deref(&self) -> &Mapper {
+        &self.mapper
+    }
+}
+
+impl DerefMut for ActivePageTable {
+    fn deref_mut(&mut self) -> &mut Mapper {
+        &mut self.mapper
+    }
 }
 
 impl ActivePageTable {
-    pub unsafe fn new() -> ActivePageTable {
+    unsafe fn new() -> ActivePageTable {
-        ActivePageTable { p4: Unique::new(table::P4) }
+        ActivePageTable { mapper: Mapper::new() }
-    }
-
-    fn p4(&self) -> &Table<Level4> {
-        unsafe { self.p4.get() }
-    }
-
-    fn p4_mut(&mut self) -> &mut Table<Level4> {
-        unsafe { self.p4.get_mut() }
-    }
-
-    pub fn translate(&self, virtual_address: VirtualAddress) -> Option<PhysicalAddress> {
-        let offset = virtual_address % PAGE_SIZE;
-        self.translate_page(Page::containing_address(virtual_address))
-            .map(|frame| frame.number * PAGE_SIZE + offset)
-    }
-
-    fn translate_page(&self, page: Page) -> Option<Frame> {
-        let p3 = self.p4().next_table(page.p4_index());
-
-        let huge_page = || {
-            p3.and_then(|p3| {
-                let p3_entry = &p3[page.p3_index()];
-                // 1GiB page?
-                if let Some(start_frame) = p3_entry.pointed_frame() {
-                    if p3_entry.flags().contains(HUGE_PAGE) {
-                        // address must be 1GiB aligned
-                        assert!(start_frame.number % (ENTRY_COUNT * ENTRY_COUNT) == 0);
-                        return Some(Frame {
-                            number: start_frame.number + page.p2_index() * ENTRY_COUNT +
-                                    page.p1_index(),
-                        });
-                    }
-                }
-                if let Some(p2) = p3.next_table(page.p3_index()) {
-                    let p2_entry = &p2[page.p2_index()];
-                    // 2MiB page?
-                    if let Some(start_frame) = p2_entry.pointed_frame() {
-                        if p2_entry.flags().contains(HUGE_PAGE) {
-                            // address must be 2MiB aligned
-                            assert!(start_frame.number % ENTRY_COUNT == 0);
-                            return Some(Frame { number: start_frame.number + page.p1_index() });
-                        }
-                    }
-                }
-                None
-            })
-        };
-
-        p3.and_then(|p3| p3.next_table(page.p3_index()))
-          .and_then(|p2| p2.next_table(page.p2_index()))
-          .and_then(|p1| p1[page.p1_index()].pointed_frame())
-          .or_else(huge_page)
-    }
-
-    pub fn map_to<A>(&mut self, page: Page, frame: Frame, flags: EntryFlags, allocator: &mut A)
-        where A: FrameAllocator
-    {
-        let mut p3 = self.p4_mut().next_table_create(page.p4_index(), allocator);
-        let mut p2 = p3.next_table_create(page.p3_index(), allocator);
-        let mut p1 = p2.next_table_create(page.p2_index(), allocator);
-
-        assert!(p1[page.p1_index()].is_unused());
-        p1[page.p1_index()].set(frame, flags | PRESENT);
-    }
-
-    pub fn map<A>(&mut self, page: Page, flags: EntryFlags, allocator: &mut A)
-        where A: FrameAllocator
-    {
-        let frame = allocator.allocate_frame().expect("out of memory");
-        self.map_to(page, frame, flags, allocator)
-    }
-
-    pub fn identity_map<A>(&mut self, frame: Frame, flags: EntryFlags, allocator: &mut A)
-        where A: FrameAllocator
-    {
-        let page = Page::containing_address(frame.start_address());
-        self.map_to(page, frame, flags, allocator)
-    }
-
-    fn unmap<A>(&mut self, page: Page, allocator: &mut A)
-        where A: FrameAllocator
-    {
-        assert!(self.translate(page.start_address()).is_some());
-
-        let p1 = self.p4_mut()
-                     .next_table_mut(page.p4_index())
-                     .and_then(|p3| p3.next_table_mut(page.p3_index()))
-                     .and_then(|p2| p2.next_table_mut(page.p2_index()))
-                     .expect("mapping code does not support huge pages");
-        let frame = p1[page.p1_index()].pointed_frame().unwrap();
-        p1[page.p1_index()].set_unused();
-        unsafe { ::x86::tlb::flush(page.start_address()) };
-        // TODO free p(1,2,3) table if empty
-        // allocator.deallocate_frame(frame);
     }
 }