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Refactor: Move ActivePageTable to new mapper submodule and rename to `Mapper`

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master
Philipp Oppermann 8 years ago
parent 4160cb6d7e
commit ce9c4d6e43
2 changed files with 119 additions and 132 deletions
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118
src/memory/paging/mapper.rs
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@ -0,0 +1,118 @@
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_unchecked(table::P4),
}
}
pub fn p4(&self) -> &Table<Level4> {
unsafe { self.p4.as_ref() }
}
pub fn p4_mut(&mut self) -> &mut Table<Level4> {
unsafe { self.p4.as_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 p4 = self.p4_mut();
let mut p3 = p4.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
{
use x86_64::instructions::tlb;
use x86_64::VirtualAddress;
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();
tlb::flush(VirtualAddress(page.start_address()));
// TODO free p(1,2,3) table if empty
//allocator.deallocate_frame(frame);
}
}

133
src/memory/paging/mod.rs
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@ -7,6 +7,7 @@ use self::temporary_page::TemporaryPage;
mod entry;
mod table;
mod temporary_page;
mod mapper;
const ENTRY_COUNT: usize = 512;
@ -44,138 +45,6 @@ impl Page {
}
}
pub struct ActivePageTable {
p4: Unique<Table<Level4>>,
}
impl ActivePageTable {
pub unsafe fn new() -> ActivePageTable {
ActivePageTable {
p4: Unique::new_unchecked(table::P4),
}
}
fn p4(&self) -> &Table<Level4> {
unsafe { self.p4.as_ref() }
}
fn p4_mut(&mut self) -> &mut Table<Level4> {
unsafe { self.p4.as_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> {
use self::entry::HUGE_PAGE;
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 p4 = self.p4_mut();
let mut p3 = p4.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
{
use x86_64::instructions::tlb;
use x86_64::VirtualAddress;
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();
tlb::flush(VirtualAddress(page.start_address()));
// TODO free p(1,2,3) table if empty
//allocator.deallocate_frame(frame);
}
pub fn with<F>(&mut self,
table: &mut InactivePageTable,
f: F)
where F: FnOnce(&mut ActivePageTable)
{
use x86_64::instructions::tlb;
// overwrite recursive mapping
self.p4_mut()[511].set(table.p4_frame.clone(), PRESENT | WRITABLE);
tlb::flush_all();
// execute f in the new context
f(self);
// TODO restore recursive mapping to original p4 table
}
}
pub struct InactivePageTable {
p4_frame: Frame,
}

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