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page_table.rs
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page_table.rs
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use addr::*;
use core::convert::TryInto;
use core::fmt::{Debug, Error, Formatter};
use core::marker::PhantomData;
use core::ops::{Index, IndexMut};
pub type Entries32 = [PageTableEntryX32; RV32_ENTRY_COUNT];
pub type Entries64 = [PageTableEntryX64; RV64_ENTRY_COUNT];
// To avoid const generic.
pub trait PTEIterableSlice<T> {
fn to_pte_slice<'a>(&'a self) -> &'a [T];
fn to_pte_slice_mut<'a>(&'a mut self) -> &'a mut [T];
fn pte_index(&self, index: usize) -> &T;
fn pte_index_mut(&mut self, index: usize) -> &mut T;
}
impl PTEIterableSlice<PageTableEntryX32> for Entries32 {
fn to_pte_slice(&self) -> &[PageTableEntryX32] {
self
}
fn to_pte_slice_mut(&mut self) -> &mut [PageTableEntryX32] {
self
}
fn pte_index(&self, index: usize) -> &PageTableEntryX32 {
&self[index]
}
fn pte_index_mut(&mut self, index: usize) -> &mut PageTableEntryX32 {
&mut self[index]
}
}
impl PTEIterableSlice<PageTableEntryX64> for Entries64 {
fn to_pte_slice(&self) -> &[PageTableEntryX64] {
self
}
fn to_pte_slice_mut(&mut self) -> &mut [PageTableEntryX64] {
self
}
fn pte_index(&self, index: usize) -> &PageTableEntryX64 {
&self[index]
}
fn pte_index_mut(&mut self, index: usize) -> &mut PageTableEntryX64 {
&mut self[index]
}
}
#[repr(C)]
pub struct PageTableWith<T: PTEIterableSlice<E>, E: PTE> {
entries: T,
phantom: PhantomData<E>,
}
impl<T: PTEIterableSlice<E>, E: PTE> PageTableWith<T, E> {
/// Clears all entries.
pub fn zero(&mut self) {
for entry in self.entries.to_pte_slice_mut().iter_mut() {
entry.set_unused();
}
}
}
impl<T: PTEIterableSlice<E>, E: PTE> Index<usize> for PageTableWith<T, E> {
type Output = E;
fn index(&self, index: usize) -> &Self::Output {
self.entries.pte_index(index)
}
}
impl<T: PTEIterableSlice<E>, E: PTE> IndexMut<usize> for PageTableWith<T, E> {
fn index_mut(&mut self, index: usize) -> &mut Self::Output {
self.entries.pte_index_mut(index)
}
}
impl<T: PTEIterableSlice<E>, E: PTE + Debug> Debug for PageTableWith<T, E> {
fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
f.debug_map()
.entries(
self.entries
.to_pte_slice()
.iter()
.enumerate()
.filter(|p| !p.1.is_unused()),
)
.finish()
}
}
pub trait PTE {
fn is_unused(&self) -> bool;
fn set_unused(&mut self);
fn flags(&self) -> PageTableFlags;
fn ppn(&self) -> usize;
fn ppn_u64(&self) -> u64;
fn addr<T: PhysicalAddress>(&self) -> T;
fn frame<T: PhysicalAddress>(&self) -> FrameWith<T>;
fn set<T: PhysicalAddress>(&mut self, frame: FrameWith<T>, flags: PageTableFlags);
fn flags_mut(&mut self) -> &mut PageTableFlags;
}
#[derive(Copy, Clone)]
#[repr(C)]
pub struct PageTableEntryX32(u32);
impl PTE for PageTableEntryX32 {
fn is_unused(&self) -> bool {
self.0 == 0
}
fn set_unused(&mut self) {
self.0 = 0;
}
fn flags(&self) -> PageTableFlags {
PageTableFlags::from_bits_truncate(self.0 as usize)
}
fn ppn(&self) -> usize {
self.ppn_u64().try_into().unwrap()
}
fn ppn_u64(&self) -> u64 {
(self.0 >> 10) as u64
}
fn addr<T: PhysicalAddress>(&self) -> T {
T::new_u64((self.ppn() as u64) << 12)
}
fn frame<T: PhysicalAddress>(&self) -> FrameWith<T> {
FrameWith::of_addr(self.addr())
}
fn set<T: PhysicalAddress>(&mut self, frame: FrameWith<T>, mut flags: PageTableFlags) {
// U540 will raise page fault when accessing page with A=0 or D=0
flags |= EF::ACCESSED | EF::DIRTY;
self.0 = ((frame.number() << 10) | flags.bits()) as u32;
}
fn flags_mut(&mut self) -> &mut PageTableFlags {
unsafe { &mut *(self as *mut _ as *mut PageTableFlags) }
}
}
impl Debug for PageTableEntryX32 {
fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
f.debug_struct("PageTableEntryX32")
.field("frame", &self.frame::<PhysAddrSv32>())
.field("flags", &self.flags())
.finish()
}
}
#[derive(Copy, Clone)]
pub struct PageTableEntryX64(u64);
impl PTE for PageTableEntryX64 {
fn is_unused(&self) -> bool {
self.0 == 0
}
fn set_unused(&mut self) {
self.0 = 0;
}
fn flags(&self) -> PageTableFlags {
PageTableFlags::from_bits_truncate(self.0 as usize)
}
fn ppn(&self) -> usize {
self.ppn_u64().try_into().unwrap()
}
fn ppn_u64(&self) -> u64 {
(self.0 >> 10) as u64
}
fn addr<T: PhysicalAddress>(&self) -> T {
T::new_u64((self.ppn() as u64) << 12)
}
fn frame<T: PhysicalAddress>(&self) -> FrameWith<T> {
FrameWith::of_addr(self.addr())
}
fn set<T: PhysicalAddress>(&mut self, frame: FrameWith<T>, mut flags: PageTableFlags) {
// U540 will raise page fault when accessing page with A=0 or D=0
flags |= EF::ACCESSED | EF::DIRTY;
self.0 = ((frame.number() << 10) | flags.bits()) as u64;
}
fn flags_mut(&mut self) -> &mut PageTableFlags {
unsafe { &mut *(self as *mut _ as *mut PageTableFlags) }
}
}
pub struct PageTableEntryX64Printer<'a, P: PhysicalAddress>(
&'a PageTableEntryX64,
PhantomData<*const P>,
);
impl<'a, P: PhysicalAddress> Debug for PageTableEntryX64Printer<'a, P> {
fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
f.debug_struct("PageTableEntryX64")
.field("frame", &self.0.frame::<P>())
.field("flags", &self.0.flags())
.finish()
}
}
impl PageTableEntryX64 {
pub fn debug_sv39<'a>(&'a self) -> PageTableEntryX64Printer<'a, PhysAddrSv39> {
PageTableEntryX64Printer(self, PhantomData)
}
pub fn debug_sv48<'a>(&'a self) -> PageTableEntryX64Printer<'a, PhysAddrSv48> {
PageTableEntryX64Printer(self, PhantomData)
}
}
impl Debug for PageTableEntryX64 {
fn fmt(&self, f: &mut Formatter) -> Result<(), Error> {
self.debug_sv48().fmt(f)
}
}
pub const RV64_ENTRY_COUNT: usize = 1 << 9;
pub const RV32_ENTRY_COUNT: usize = 1 << 10;
#[cfg(riscv64)]
pub const ENTRY_COUNT: usize = RV64_ENTRY_COUNT;
#[cfg(riscv32)]
pub const ENTRY_COUNT: usize = RV32_ENTRY_COUNT;
#[cfg(riscv64)]
pub type PageTableEntry = PageTableEntryX64;
#[cfg(riscv32)]
pub type PageTableEntry = PageTableEntryX32;
#[cfg(riscv64)]
pub type Entries = Entries64;
#[cfg(riscv32)]
pub type Entries = Entries32;
#[cfg(not(any(riscv32, riscv64)))]
pub const ENTRY_COUNT: usize = 1 << 0;
#[cfg(not(any(riscv32, riscv64)))]
pub type Entries = Entries64;
pub type PageTableX32 = PageTableWith<Entries32, PageTableEntryX32>;
pub type PageTableX64 = PageTableWith<Entries64, PageTableEntryX64>;
#[cfg(riscv64)]
pub type PageTable = PageTableX64;
#[cfg(riscv32)]
pub type PageTable = PageTableX32;
bitflags! {
/// Possible flags for a page table entry.
pub struct PageTableFlags: usize {
const VALID = 1 << 0;
const READABLE = 1 << 1;
const WRITABLE = 1 << 2;
const EXECUTABLE = 1 << 3;
const USER = 1 << 4;
const GLOBAL = 1 << 5;
const ACCESSED = 1 << 6;
const DIRTY = 1 << 7;
const RESERVED1 = 1 << 8;
const RESERVED2 = 1 << 9;
}
}
type EF = PageTableFlags;