michaelkuc6/blog_os
1
0
Fork 0
mirror of https://github.com/phil-opp/blog_os.git synced 2025-12-17 06:47:49 +00:00
Code Issues Projects Releases Wiki Activity

Split mapping functions of ActivePageTable into mapper subtype

Browse Source
This commit is contained in:
Philipp Oppermann
2015-12-31 02:23:02 +01:00
parent 716e3f7359
commit a100d5f63f
2 changed files with 138 additions and 97 deletions
Download Patch File Download Diff File Expand all files Collapse all files

117
src/memory/paging/mod.rs
View File

@@ -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 {
ActivePageTable { p4: Unique::new(table::P4) }
}
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);
unsafe fn new() -> ActivePageTable {
ActivePageTable { mapper: Mapper::new() }
}
}