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Split mapping functions of ActivePageTable into mapper subtype
This commit is contained in:
Philipp Oppermann
118
src/memory/paging/mapper.rs
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118
src/memory/paging/mapper.rs
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@@ -0,0 +1,118 @@
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// Copyright 2015 Philipp Oppermann. See the README.md
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// file at the top-level directory of this distribution.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use super::{VirtualAddress, PhysicalAddress, Page, ENTRY_COUNT};
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use super::entry::*;
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use super::table::{self, Table, Level4, Level1};
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use memory::{PAGE_SIZE, Frame, FrameAllocator};
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use core::ptr::Unique;
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pub struct Mapper {
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p4: Unique<Table<Level4>>,
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}
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impl Mapper {
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pub unsafe fn new() -> Mapper {
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Mapper { p4: Unique::new(table::P4) }
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}
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pub fn p4(&self) -> &Table<Level4> {
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unsafe { self.p4.get() }
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}
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pub fn p4_mut(&mut self) -> &mut Table<Level4> {
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unsafe { self.p4.get_mut() }
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}
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pub fn translate(&self, virtual_address: VirtualAddress) -> Option<PhysicalAddress> {
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let offset = virtual_address % PAGE_SIZE;
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self.translate_page(Page::containing_address(virtual_address))
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.map(|frame| frame.number * PAGE_SIZE + offset)
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}
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pub fn translate_page(&self, page: Page) -> Option<Frame> {
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let p3 = self.p4().next_table(page.p4_index());
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let huge_page = || {
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p3.and_then(|p3| {
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let p3_entry = &p3[page.p3_index()];
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// 1GiB page?
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if let Some(start_frame) = p3_entry.pointed_frame() {
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if p3_entry.flags().contains(HUGE_PAGE) {
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// address must be 1GiB aligned
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assert!(start_frame.number % (ENTRY_COUNT * ENTRY_COUNT) == 0);
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return Some(Frame {
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number: start_frame.number + page.p2_index() * ENTRY_COUNT +
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page.p1_index(),
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});
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}
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}
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if let Some(p2) = p3.next_table(page.p3_index()) {
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let p2_entry = &p2[page.p2_index()];
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// 2MiB page?
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if let Some(start_frame) = p2_entry.pointed_frame() {
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if p2_entry.flags().contains(HUGE_PAGE) {
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// address must be 2MiB aligned
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assert!(start_frame.number % ENTRY_COUNT == 0);
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return Some(Frame { number: start_frame.number + page.p1_index() });
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}
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}
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}
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None
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})
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};
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p3.and_then(|p3| p3.next_table(page.p3_index()))
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.and_then(|p2| p2.next_table(page.p2_index()))
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.and_then(|p1| p1[page.p1_index()].pointed_frame())
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.or_else(huge_page)
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}
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pub fn map_to<A>(&mut self, page: Page, frame: Frame, flags: EntryFlags, allocator: &mut A)
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where A: FrameAllocator
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{
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let mut p3 = self.p4_mut().next_table_create(page.p4_index(), allocator);
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let mut p2 = p3.next_table_create(page.p3_index(), allocator);
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let mut p1 = p2.next_table_create(page.p2_index(), allocator);
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assert!(p1[page.p1_index()].is_unused());
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p1[page.p1_index()].set(frame, flags | PRESENT);
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}
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pub fn map<A>(&mut self, page: Page, flags: EntryFlags, allocator: &mut A)
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where A: FrameAllocator
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{
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let frame = allocator.allocate_frame().expect("out of memory");
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self.map_to(page, frame, flags, allocator)
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}
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pub fn identity_map<A>(&mut self, frame: Frame, flags: EntryFlags, allocator: &mut A)
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where A: FrameAllocator
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{
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let page = Page::containing_address(frame.start_address());
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self.map_to(page, frame, flags, allocator)
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}
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pub fn unmap<A>(&mut self, page: Page, allocator: &mut A)
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where A: FrameAllocator
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{
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assert!(self.translate(page.start_address()).is_some());
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let p1 = self.p4_mut()
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.next_table_mut(page.p4_index())
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.and_then(|p3| p3.next_table_mut(page.p3_index()))
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.and_then(|p2| p2.next_table_mut(page.p2_index()))
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.expect("mapping code does not support huge pages");
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let frame = p1[page.p1_index()].pointed_frame().unwrap();
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p1[page.p1_index()].set_unused();
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unsafe { ::x86::tlb::flush(page.start_address()) };
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// TODO free p(1,2,3) table if empty
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// allocator.deallocate_frame(frame);
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}
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}
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@@ -11,11 +11,14 @@ pub use self::entry::*;
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use memory::{PAGE_SIZE, Frame, FrameAllocator};
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use self::table::{Table, Level4};
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use self::temporary_page::TemporaryPage;
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pub use self::mapper::Mapper;
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use core::ops::{Deref, DerefMut};
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use core::ptr::Unique;
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mod entry;
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mod table;
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mod temporary_page;
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mod mapper;
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const ENTRY_COUNT: usize = 512;
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@@ -54,106 +57,26 @@ impl Page {
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}
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pub struct ActivePageTable {
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p4: Unique<Table<Level4>>,
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mapper: Mapper,
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}
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impl Deref for ActivePageTable {
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type Target = Mapper;
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fn deref(&self) -> &Mapper {
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&self.mapper
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}
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}
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impl DerefMut for ActivePageTable {
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fn deref_mut(&mut self) -> &mut Mapper {
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&mut self.mapper
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}
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}
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impl ActivePageTable {
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pub unsafe fn new() -> ActivePageTable {
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ActivePageTable { p4: Unique::new(table::P4) }
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}
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fn p4(&self) -> &Table<Level4> {
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unsafe { self.p4.get() }
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}
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fn p4_mut(&mut self) -> &mut Table<Level4> {
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unsafe { self.p4.get_mut() }
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}
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pub fn translate(&self, virtual_address: VirtualAddress) -> Option<PhysicalAddress> {
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let offset = virtual_address % PAGE_SIZE;
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self.translate_page(Page::containing_address(virtual_address))
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.map(|frame| frame.number * PAGE_SIZE + offset)
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}
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fn translate_page(&self, page: Page) -> Option<Frame> {
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let p3 = self.p4().next_table(page.p4_index());
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let huge_page = || {
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p3.and_then(|p3| {
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let p3_entry = &p3[page.p3_index()];
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// 1GiB page?
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if let Some(start_frame) = p3_entry.pointed_frame() {
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if p3_entry.flags().contains(HUGE_PAGE) {
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// address must be 1GiB aligned
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assert!(start_frame.number % (ENTRY_COUNT * ENTRY_COUNT) == 0);
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return Some(Frame {
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number: start_frame.number + page.p2_index() * ENTRY_COUNT +
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page.p1_index(),
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});
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}
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}
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if let Some(p2) = p3.next_table(page.p3_index()) {
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let p2_entry = &p2[page.p2_index()];
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// 2MiB page?
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if let Some(start_frame) = p2_entry.pointed_frame() {
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if p2_entry.flags().contains(HUGE_PAGE) {
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// address must be 2MiB aligned
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assert!(start_frame.number % ENTRY_COUNT == 0);
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return Some(Frame { number: start_frame.number + page.p1_index() });
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}
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}
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}
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None
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})
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};
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p3.and_then(|p3| p3.next_table(page.p3_index()))
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.and_then(|p2| p2.next_table(page.p2_index()))
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.and_then(|p1| p1[page.p1_index()].pointed_frame())
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.or_else(huge_page)
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}
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pub fn map_to<A>(&mut self, page: Page, frame: Frame, flags: EntryFlags, allocator: &mut A)
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where A: FrameAllocator
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{
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let mut p3 = self.p4_mut().next_table_create(page.p4_index(), allocator);
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let mut p2 = p3.next_table_create(page.p3_index(), allocator);
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let mut p1 = p2.next_table_create(page.p2_index(), allocator);
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assert!(p1[page.p1_index()].is_unused());
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p1[page.p1_index()].set(frame, flags | PRESENT);
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}
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pub fn map<A>(&mut self, page: Page, flags: EntryFlags, allocator: &mut A)
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where A: FrameAllocator
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{
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let frame = allocator.allocate_frame().expect("out of memory");
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self.map_to(page, frame, flags, allocator)
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}
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pub fn identity_map<A>(&mut self, frame: Frame, flags: EntryFlags, allocator: &mut A)
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where A: FrameAllocator
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{
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let page = Page::containing_address(frame.start_address());
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self.map_to(page, frame, flags, allocator)
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}
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fn unmap<A>(&mut self, page: Page, allocator: &mut A)
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where A: FrameAllocator
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{
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assert!(self.translate(page.start_address()).is_some());
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let p1 = self.p4_mut()
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.next_table_mut(page.p4_index())
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.and_then(|p3| p3.next_table_mut(page.p3_index()))
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.and_then(|p2| p2.next_table_mut(page.p2_index()))
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.expect("mapping code does not support huge pages");
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let frame = p1[page.p1_index()].pointed_frame().unwrap();
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p1[page.p1_index()].set_unused();
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unsafe { ::x86::tlb::flush(page.start_address()) };
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// TODO free p(1,2,3) table if empty
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// allocator.deallocate_frame(frame);
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unsafe fn new() -> ActivePageTable {
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ActivePageTable { mapper: Mapper::new() }
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}
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}
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