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Updates for the old paging code

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This commit is contained in:
Philipp Oppermann
2015-12-03 18:36:53 +01:00
parent ae49ab5072
commit ace53fad91
2 changed files with 42 additions and 45 deletions
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85
src/memory/paging/mod.rs
View File

@@ -1,4 +1,4 @@
use memory::Frame;
use memory::{Frame, FrameAllocator};
pub const PAGE_SIZE: usize = 4096;
const ENTRY_SIZE: usize = 8;
@@ -7,48 +7,6 @@ const ENTRY_COUNT: usize = 512;
pub type PhysicalAddress = usize;
pub type VirtualAddress = usize;
// pub fn translate(virtual_address: usize) -> Option<PhysicalAddress> {
// let page = Page::containing_address(virtual_address);
// let offset = virtual_address % PAGE_SIZE;
//
// let p4_entry = page.p4_table().entry(page.p4_index());
// assert!(!p4_entry.flags().contains(HUGE_PAGE));
// if !p4_entry.flags().contains(PRESENT) {
// return None;
// }
//
// let p3_entry = page.p3_table().entry(page.p3_index());
// if !p3_entry.flags().contains(PRESENT) {
// return None;
// }
// if p3_entry.flags().contains(HUGE_PAGE) {
// 1GiB page (address must be 1GiB aligned)
// let start_frame_number = p3_entry.pointed_frame().number;
// assert!(start_frame_number % (ENTRY_COUNT * ENTRY_COUNT) == 0);
// let frame_number = start_frame_number + page.p2_index() * ENTRY_COUNT + page.p1_index();
// return Some(frame_number * PAGE_SIZE + offset);
// }
//
// let p2_entry = page.p2_table().entry(page.p2_index());
// if !p2_entry.flags().contains(PRESENT) {
// return None;
// }
// if p2_entry.flags().contains(HUGE_PAGE) {
// 2MiB page (address must be 2MiB aligned)
// let start_frame_number = p2_entry.pointed_frame().number;
// assert!(start_frame_number % ENTRY_COUNT == 0);
// let frame_number = start_frame_number + page.p1_index();
// return Some(frame_number * PAGE_SIZE + offset);
// }
//
// let p1_entry = page.p1_table().entry(page.p1_index());
// assert!(!p1_entry.flags().contains(HUGE_PAGE));
// if !p1_entry.flags().contains(PRESENT) {
// return None;
// }
// Some(p1_entry.pointed_frame().number * PAGE_SIZE + offset)
// }
pub fn translate(virtual_address: usize) -> Option<PhysicalAddress> {
let page = Page::containing_address(virtual_address);
let offset = virtual_address % PAGE_SIZE;
@@ -94,6 +52,37 @@ pub fn translate(virtual_address: usize) -> Option<PhysicalAddress> {
Some(frame_number * PAGE_SIZE + offset)
}
pub fn map_to<A>(page: &Page, frame: Frame, flags: TableEntryFlags, allocator: &mut A)
where A: FrameAllocator
{
let p4_index = page.p4_index();
let p3_index = page.p3_index();
let p2_index = page.p2_index();
let p1_index = page.p1_index();
let mut p4 = page.p4_table();
if !p4.entry(p4_index).flags().contains(PRESENT) {
let frame = allocator.allocate_frame().expect("no frames available");
p4.set_entry(p4_index, TableEntry::new(frame, PRESENT | WRITABLE));
unsafe { page.p3_table() }.zero();
}
let mut p3 = unsafe { page.p3_table() };
if !p3.entry(p3_index).flags().contains(PRESENT) {
let frame = allocator.allocate_frame().expect("no frames available");
p3.set_entry(p3_index, TableEntry::new(frame, PRESENT | WRITABLE));
unsafe { page.p2_table() }.zero();
}
let mut p2 = unsafe { page.p2_table() };
if !p2.entry(p2_index).flags().contains(PRESENT) {
let frame = allocator.allocate_frame().expect("no frames available");
p2.set_entry(p2_index, TableEntry::new(frame, PRESENT | WRITABLE));
unsafe { page.p1_table() }.zero();
}
let mut p1 = unsafe { page.p1_table() };
assert!(!p1.entry(p1_index).flags().contains(PRESENT));
p1.set_entry(p1_index, TableEntry::new(frame, flags));
}
pub struct Page {
number: usize,
}
@@ -171,13 +160,18 @@ impl Table {
let entry_address = self.0.start_address() + index * ENTRY_SIZE;
unsafe { *(entry_address as *mut _) = value }
}
fn zero(&mut self) {
let page = self.0.start_address() as *mut [TableEntry; ENTRY_COUNT];
unsafe { *page = [TableEntry::unused(); ENTRY_COUNT] };
}
}
#[derive(Debug, Clone, Copy)]
struct TableEntry(u64);
impl TableEntry {
fn ununsed() -> TableEntry {
const fn unused() -> TableEntry {
TableEntry(0)
}
@@ -209,3 +203,6 @@ bitflags! {
const NO_EXECUTE = 1 << 63,
}
}
mod tables;

2
src/memory/paging/tables.rs
View File

@@ -187,7 +187,7 @@ impl<L> Table<L> where L: HierachicalLevel
fn next_table_internal(&self) -> Table<L::NextLevel> {
Table {
table_page: Page {
number: ((self.target_page_number << 9) & 0o_777_777_777_777) | self.index(),
number: ((self.table_page.number << 9) & 0o_777_777_777_777) | self.index(),
},
target_page_number: self.target_page_number,
_phantom: PhantomData,