[WIP]: memory paging

master
Mahdi Dibaiee 7 years ago
parent f300229fa4
commit 23fe830220

6
Cargo.lock generated

@ -2,6 +2,7 @@
name = "mahdi_os"
version = "0.1.0"
dependencies = [
"bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
"multiboot2 0.1.0 (git+https://github.com/phil-opp/multiboot2-elf64)",
"rlibc 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
"spin 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
@ -12,6 +13,11 @@ name = "bitflags"
version = "0.4.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "bitflags"
version = "0.7.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "multiboot2"
version = "0.1.0"

@ -9,6 +9,7 @@ crate-type = ["staticlib"]
[dependencies]
rlibc = "0.1.4"
spin = "0.3.4"
bitflags = "0.7.0"
[dependencies.multiboot2]
git = "https://github.com/phil-opp/multiboot2-elf64"

@ -13,6 +13,9 @@ start:
call check_long_mode
call set_up_page_tables
mov eax, p4_table
or eax, 0b11 ; present + writable
mov [p4_table + 511 * 8], eax
call enable_paging
call set_up_SSE

@ -3,6 +3,8 @@
#![feature(unique)]
#![feature(const_fn)]
#[macro_use]
extern crate bitflags;
extern crate rlibc;
extern crate spin;
extern crate multiboot2;

@ -1,5 +1,8 @@
pub use self::area_frame_allocator::AreaFrameAllocator;
use self::paging::PhysicalAddress;
mod area_frame_allocator;
mod paging;
pub const PAGE_SIZE: usize = 4096;
@ -12,6 +15,10 @@ impl Frame {
fn containing_address(address: usize) -> Frame {
Frame { number: address / PAGE_SIZE }
}
fn start_address(&self) -> PhysicalAddress {
self.number * PAGE_SIZE
}
}
pub trait FrameAllocator {

@ -0,0 +1,49 @@
use memory::PAGE_SIZE;
pub struct Entry(u64);
impl Entry {
pub fn is_unused(&self) -> bool {
self.0 == 0
}
pub fn set_unused(&mut self) {
self.0 = 0;
}
pub fn flags(&self) -> EntryFlags {
EntryFlags::from_bits_truncate(self.0)
}
pub fn pointed_frame(&self) -> Option<Frame> {
if self.flags().contains(PRESENT) {
Some(Frame::containing_address(
self.0 as usize & 0x000fffff_fffff000
))
} else {
None
}
}
pub fn set (&mut self, frame: Frame, flags: EntryFlags) {
assert!(frame.start_address() & !x000fffff_fffff000 == 0);
self.0 = (frame.start_address() as u64) | flags.bits();
}
}
bitflags! {
pub flags EntryFlags: u64 {
const PRESENT = 1 << 0,
const WRITABLE = 1 << 1,
const USER_ACCESSABLE = 1 << 2,
const WRITE_THROUGH = 1 << 3,
const NO_CACHE = 1 << 4,
const ACCESSED = 1 << 5,
const DIRTY = 1 << 6,
const HUGE_PAGE = 1 << 7,
const GLOBAL = 1 << 8,
const NO_EXECUTE = 1 << 63,
}
}

@ -0,0 +1,57 @@
use memory::PAGE_SIZE;
use memory::Frame;
const ENTRY_COUNT: usize = 512;
pub type PhysicalAddress = usize;
pub type VirtualAddress = usize;
pub struct Page {
number: usize,
}
pub struct Entry(u64);
impl Entry {
pub fn is_unused(&self) -> bool {
self.0 == 0
}
pub fn set_unused(&mut self) {
self.0 = 0;
}
pub fn flags(&self) -> EntryFlags {
EntryFlags::from_bits_truncate(self.0)
}
pub fn pointed_frame(&self) -> Option<Frame> {
if self.flags().contains(PRESENT) {
Some(Frame::containing_address(
self.0 as usize & 0x000fffff_fffff000
))
} else {
None
}
}
pub fn set(&mut self, frame: Frame, flags: EntryFlags) {
assert!(frame.start_address() & !0x000fffff_fffff000 == 0);
self.0 = (frame.start_address() as u64) | flags.bits();
}
}
bitflags! {
pub flags EntryFlags: u64 {
const PRESENT = 1 << 0,
const WRITABLE = 1 << 1,
const USER_ACCESSABLE = 1 << 2,
const WRITE_THROUGH = 1 << 3,
const NO_CACHE = 1 << 4,
const ACCESSED = 1 << 5,
const DIRTY = 1 << 6,
const HUGE_PAGE = 1 << 7,
const GLOBAL = 1 << 8,
const NO_EXECUTE = 1 << 63,
}
}

@ -0,0 +1,89 @@
use memory::paging::entry::*;
use memory::paging::ENTRY_COUNT;
use core::ops::{Index, IndexMut};
use core::marker::PhantomData;
pub const P4: *mut Table<Level4> = 0xffffffff_fffff000 as *mut _;
pub trait TableLevel {}
pub enum Level 4 {}
pub enum Level 3 {}
pub enum Level 2 {}
pub enum Level 1 {}
impl TableLevel for Level4 {}
impl TableLevel for Level3 {}
impl TableLevel for Level2 {}
impl TableLevel for Level1 {}
pub trait HierarchicalLevel: TableLevel {
type NextLevel: TableLevel;
}
impl HierarchicalLevel for Level4 {
type NextLevel: Level3
}
impl HierarchicalLevel for Level3 {
type NextLevel: Level2
}
impl HierarchicalLevel for Level2 {
type NextLevel: Level1
}
pub struct Table<L: TableLevel> {
entries : [Entry; ENTRY_COUNT],
level: PhantomData<L>
}
impl<L> Table<L> where L: TableLevel {
pub fn zero(&mut self) {
for entry in self.entries.iter_mut() {
entry.set_unused();
}
}
}
impl<L> Table<L> where L: HierarchicalLevel {
fn next_table_address(&self, index: usize) -> Option<usize> {
let entry_flags = self[index].flags();
if entry_flags.contains(PRESENT) && !entry_flags.contains(HUGE_PAGE) {
let table_address = self as *const _ as usize;
Some((table_address << 9) | (index << 12))
} else {
None
}
}
pub fn next_table(&self, index: usize) -> Option<&Table<L::NextLevel>> {
self.next_table_address(index)
.map(|address| unsafe { &*(address as *const _) })
}
pub fn next_table_mut(&mut self, index: usize) -> Option<&mut Table<L::NextLevel>> {
self.next_table_address(index)
.map(|address| unsafe { &mut *(address as *mut _) })
}
}
impl<L> Index<usize> for Table<L> where L: TableLevel {
type Output = Entry;
fn index(&self, index: usize) -> &Entry {
&self.entries[index]
}
}
impl<L> IndexMut<usize> for Table<L> where L: TableLevel {
fn index_mut(&mut self, index: usize) -> &mut Entry {
&mut self.entries[index]
}
}
fn test() {
let p4 = unsafe { &*P4 };
p4.next_table(4@)
.and_then(|p3| p3.next_table(1337))
.and_then(|p2| p2.next_table(0xdeadbeaf))
.and_then(|p1| p1.next_table(0xcafebabe))
}
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