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use super::{
frame_alloc, FrameTracker, MapPermission, PhysAddr, PhysPageNum, StepByOne, VirtAddr,
VirtPageNum,
};
use _core::ops::{Index, IndexMut};
use alloc::vec;
use alloc::vec::Vec;
use alloc::{string::String, sync::Arc};
use bitflags::*;
use core::fmt::Error;
bitflags! {
pub struct PTEFlags: u8 {
const V = 1 << 0;
const R = 1 << 1;
const W = 1 << 2;
const X = 1 << 3;
const U = 1 << 4;
const G = 1 << 5;
const A = 1 << 6;
const D = 1 << 7;
}
}
#[derive(Copy, Clone)]
#[repr(C)]
pub struct PageTableEntry {
pub bits: usize,
}
impl PageTableEntry {
pub fn new(ppn: PhysPageNum, flags: PTEFlags) -> Self {
PageTableEntry {
bits: ppn.0 << 10 | flags.bits as usize,
}
}
pub fn empty() -> Self {
PageTableEntry { bits: 0 }
}
pub fn ppn(&self) -> PhysPageNum {
(self.bits >> 10 & ((1usize << 44) - 1)).into()
}
pub fn flags(&self) -> PTEFlags {
PTEFlags::from_bits(self.bits as u8).unwrap()
}
pub fn is_valid(&self) -> bool {
(self.flags() & PTEFlags::V) != PTEFlags::empty()
}
pub fn is_dirty(&self) -> bool {
(self.flags() & PTEFlags::D) != PTEFlags::empty()
}
pub fn readable(&self) -> bool {
(self.flags() & PTEFlags::R) != PTEFlags::empty()
}
pub fn writable(&self) -> bool {
(self.flags() & PTEFlags::W) != PTEFlags::empty()
}
pub fn executable(&self) -> bool {
(self.flags() & PTEFlags::X) != PTEFlags::empty()
}
pub fn set_permission(&mut self, flags: MapPermission) {
self.bits = (self.bits & 0xffff_ffff_ffff_ffe1) | (flags.bits() as usize)
}
}
pub struct PageTable {
root_ppn: PhysPageNum,
frames: Vec<Arc<FrameTracker>>,
}
impl PageTable {
pub fn new() -> Self {
let frame = frame_alloc().unwrap();
PageTable {
root_ppn: frame.ppn,
frames: vec![frame],
}
}
pub fn from_token(satp: usize) -> Self {
Self {
root_ppn: PhysPageNum::from(satp & ((1usize << 44) - 1)),
frames: Vec::new(),
}
}
pub fn is_mapped(&mut self, vpn: VirtPageNum) -> bool {
if let Some(i) = self.find_pte(vpn) {
if i.is_valid() {
true
} else {
false
}
} else {
false
}
}
fn find_pte_create(&mut self, vpn: VirtPageNum) -> Option<&mut PageTableEntry> {
let idxs = vpn.indexes();
let mut ppn = self.root_ppn;
let mut result: Option<&mut PageTableEntry> = None;
for i in 0..3 {
let pte = &mut ppn.get_pte_array()[idxs[i]];
if i == 2 {
result = Some(pte);
break;
}
if !pte.is_valid() {
let frame = frame_alloc().unwrap();
*pte = PageTableEntry::new(frame.ppn, PTEFlags::V);
self.frames.push(frame);
}
ppn = pte.ppn();
}
result
}
fn find_pte(&self, vpn: VirtPageNum) -> Option<&PageTableEntry> {
let idxs = vpn.indexes();
let mut ppn = self.root_ppn;
let mut result: Option<&PageTableEntry> = None;
for i in 0..3 {
let pte = &ppn.get_pte_array()[idxs[i]];
if !pte.is_valid() {
return None;
}
if i == 2 {
result = Some(pte);
break;
}
ppn = pte.ppn();
}
result
}
fn find_pte_refmut(&self, vpn: VirtPageNum) -> Option<&mut PageTableEntry> {
let idxs = vpn.indexes();
let mut ppn = self.root_ppn;
let mut result: Option<&mut PageTableEntry> = None;
for i in 0..3 {
let pte = &mut ppn.get_pte_array()[idxs[i]];
if !pte.is_valid() {
return None;
}
if i == 2 {
result = Some(pte);
break;
}
ppn = pte.ppn();
}
result
}
#[allow(unused)]
pub fn map(&mut self, vpn: VirtPageNum, ppn: PhysPageNum, flags: PTEFlags) {
let pte = self.find_pte_create(vpn).unwrap();
assert!(!pte.is_valid(), "vpn {:?} is mapped before mapping", vpn);
*pte = PageTableEntry::new(ppn, flags | PTEFlags::V);
}
#[allow(unused)]
pub fn unmap(&mut self, vpn: VirtPageNum) {
let pte = self.find_pte_refmut(vpn).unwrap();
assert!(pte.is_valid(), "vpn {:?} is invalid before unmapping", vpn);
*pte = PageTableEntry::empty();
}
pub fn translate(&self, vpn: VirtPageNum) -> Option<PageTableEntry> {
self.find_pte(vpn).map(|pte| pte.clone())
}
pub fn translate_va(&self, va: VirtAddr) -> Option<PhysAddr> {
self.find_pte(va.clone().floor()).map(|pte| {
let aligned_pa: PhysAddr = pte.ppn().into();
let offset = va.page_offset();
let aligned_pa_usize: usize = aligned_pa.into();
(aligned_pa_usize + offset).into()
})
}
pub fn translate_refmut(&self, vpn: VirtPageNum) -> Option<&mut PageTableEntry> {
self.find_pte_refmut(vpn)
}
pub fn token(&self) -> usize {
8usize << 60 | self.root_ppn.0
}
pub fn set_pte_flags(&mut self, vpn: VirtPageNum, flags: MapPermission) -> Result<(), Error> {
if let Some(pte) = self.find_pte_refmut(vpn) {
pte.set_permission(flags);
Ok(())
} else {
Err(Error)
}
}
}
pub fn translated_byte_buffer_append_to_existed_vec(
existed_vec: Option<Vec<&'static mut [u8]>>,
token: usize,
ptr: *const u8,
len: usize,
) -> Vec<&'static mut [u8]> {
let page_table = PageTable::from_token(token);
let mut start = ptr as usize;
let end = start + len;
let mut v = existed_vec.unwrap_or_default();
while start < end {
let start_va = VirtAddr::from(start);
let mut vpn = start_va.floor();
let ppn = page_table.translate(vpn).unwrap().ppn();
vpn.step();
let mut end_va: VirtAddr = vpn.into();
end_va = end_va.min(VirtAddr::from(end));
if end_va.page_offset() == 0 {
v.push(&mut ppn.get_bytes_array()[start_va.page_offset()..]);
} else {
v.push(&mut ppn.get_bytes_array()[start_va.page_offset()..end_va.page_offset()]);
}
start = end_va.into();
}
v
}
pub fn translated_byte_buffer(token: usize, ptr: *const u8, len: usize) -> Vec<&'static mut [u8]> {
translated_byte_buffer_append_to_existed_vec(None, token, ptr, len)
}
pub fn translated_str(token: usize, ptr: *const u8) -> String {
let page_table = PageTable::from_token(token);
let mut string = String::new();
let mut va = ptr as usize;
loop {
let ch: u8 = *(page_table
.translate_va(VirtAddr::from(va))
.unwrap()
.get_mut());
if ch == 0 {
break;
}
string.push(ch as char);
va += 1;
}
string
}
pub fn translated_ref<T>(token: usize, ptr: *const T) -> &'static T {
let page_table = PageTable::from_token(token);
page_table
.translate_va(VirtAddr::from(ptr as usize))
.unwrap()
.get_ref()
}
pub fn translated_refmut<T>(token: usize, ptr: *mut T) -> &'static mut T {
let page_table = PageTable::from_token(token);
let va = ptr as usize;
page_table
.translate_va(VirtAddr::from(va))
.unwrap()
.get_mut()
}
pub struct UserBuffer {
pub buffers: Vec<&'static mut [u8]>,
pub len: usize,
}
impl UserBuffer {
pub fn new(buffers: Vec<&'static mut [u8]>) -> Self {
Self {
len: buffers.iter().map(|buffer| buffer.len()).sum(),
buffers,
}
}
pub fn len(&self) -> usize {
self.len
}
pub fn read(&self, dst: &mut [u8]) -> usize {
let mut start = 0;
let dst_len = dst.len();
for buffer in self.buffers.iter() {
let end = start + buffer.len();
if end > dst_len {
dst[start..].copy_from_slice(&buffer[..dst_len - start]);
return dst_len;
} else {
dst[start..end].copy_from_slice(buffer);
}
start = end;
}
self.len
}
pub fn write(&mut self, src: &[u8]) -> usize {
let mut start = 0;
let src_len = src.len();
for buffer in self.buffers.iter_mut() {
let end = start + buffer.len();
if end > src_len {
buffer[..src_len - start].copy_from_slice(&src[start..]);
return src_len;
} else {
buffer.copy_from_slice(&src[start..end]);
}
start = end;
}
self.len
}
pub fn write_at(&mut self, offset: usize, src: &[u8]) -> usize {
if offset >= self.len {
return 0;
}
let mut write_bytes = 0usize;
let mut dst_start = 0usize;
for buffer in self.buffers.iter_mut() {
let dst_end = dst_start + buffer.len();
let copy_dst_start = dst_start.max(offset);
let copy_dst_end = dst_end.min(src.len() + offset);
if copy_dst_start >= copy_dst_end {
dst_start = dst_end;
continue;
}
let copy_src_start = copy_dst_start - offset;
let copy_src_end = copy_dst_end - offset;
let copy_buffer_start = copy_dst_start - dst_start;
let copy_buffer_end = copy_dst_end - dst_start;
buffer[copy_buffer_start..copy_buffer_end]
.copy_from_slice(&src[copy_src_start..copy_src_end]);
write_bytes += copy_dst_end - copy_dst_start;
dst_start = dst_end;
}
write_bytes
}
pub fn clear(&mut self) {
self.buffers.iter_mut().for_each(|buffer| {
buffer.fill(0);
})
}
}
impl Index<usize> for UserBuffer {
type Output = u8;
fn index(&self, index: usize) -> &Self::Output {
assert!((index as usize) < self.len);
let mut left = index;
for buffer in &self.buffers {
if (left as usize) < buffer.len() {
return &buffer[left];
} else {
left -= buffer.len();
}
}
unreachable!();
}
}
impl IndexMut<usize> for UserBuffer {
fn index_mut(&mut self, index: usize) -> &mut Self::Output {
assert!((index as usize) < self.len);
let mut left = index;
for buffer in &mut self.buffers {
if (left as usize) < buffer.len() {
return &mut buffer[left];
} else {
left -= buffer.len();
}
}
unreachable!();
}
}
impl IntoIterator for UserBuffer {
type Item = *mut u8;
type IntoIter = UserBufferIterator;
fn into_iter(self) -> Self::IntoIter {
UserBufferIterator {
buffers: self.buffers,
current_buffer: 0,
current_idx: 0,
}
}
}
pub struct UserBufferIterator {
buffers: Vec<&'static mut [u8]>,
current_buffer: usize,
current_idx: usize,
}
impl Iterator for UserBufferIterator {
type Item = *mut u8;
fn next(&mut self) -> Option<Self::Item> {
if self.current_buffer >= self.buffers.len() {
None
} else {
let r = &mut self.buffers[self.current_buffer][self.current_idx] as *mut _;
if self.current_idx + 1 == self.buffers[self.current_buffer].len() {
self.current_idx = 0;
self.current_buffer += 1;
} else {
self.current_idx += 1;
}
Some(r)
}
}
}
pub fn copy_from_user<T: 'static + Copy>(token: usize, src: *const T, dst: *mut T) {
let size = core::mem::size_of::<T>();
if VirtPageNum::from(src as usize) == VirtPageNum::from(src as usize + size - 1) {
unsafe { *dst = *translated_ref(token, src) };
} else {
UserBuffer::new(translated_byte_buffer(token, src as *const u8, size))
.read(unsafe { core::slice::from_raw_parts_mut(dst as *mut u8, size) });
}
}
pub fn copy_from_user_array<T: 'static + Copy>(
token: usize,
src: *const T,
dst: *mut T,
len: usize,
) {
let size = core::mem::size_of::<T>() * len;
if VirtPageNum::from(src as usize) == VirtPageNum::from(src as usize + size - 1) {
let page_table = PageTable::from_token(token);
let src_pa = page_table
.translate_va(VirtAddr::from(src as usize))
.unwrap();
unsafe {
core::slice::from_raw_parts_mut(dst as *mut T, len)
.copy_from_slice(core::slice::from_raw_parts(src_pa.0 as *const T, len))
};
} else {
UserBuffer::new(translated_byte_buffer(token, src as *const u8, size))
.read(unsafe { core::slice::from_raw_parts_mut(dst as *mut u8, size) });
}
}
pub fn copy_to_user<T: 'static + Copy>(token: usize, src: *const T, dst: *mut T) {
let size = core::mem::size_of::<T>();
if VirtPageNum::from(dst as usize) == VirtPageNum::from(dst as usize + size - 1) {
unsafe { *translated_refmut(token, dst) = *src };
} else {
UserBuffer::new(translated_byte_buffer(token, dst as *mut u8, size))
.write(unsafe { core::slice::from_raw_parts(src as *const u8, size) });
}
}
pub fn copy_to_user_array<T: 'static + Copy>(token: usize, src: *const T, dst: *mut T, len: usize) {
let size = core::mem::size_of::<T>() * len;
if VirtPageNum::from(dst as usize) == VirtPageNum::from(dst as usize + size - 1) {
let page_table = PageTable::from_token(token);
let dst_pa = page_table
.translate_va(VirtAddr::from(dst as usize))
.unwrap();
unsafe {
core::slice::from_raw_parts_mut(dst_pa.0 as *mut T, len)
.copy_from_slice(core::slice::from_raw_parts(src as *const T, len))
};
} else {
UserBuffer::new(translated_byte_buffer(token, dst as *mut u8, size))
.write(unsafe { core::slice::from_raw_parts(src as *const u8, size) });
}
}
pub fn copy_to_user_string(token: usize, src: &str, dst: *mut u8) {
let size = src.len();
if VirtPageNum::from(dst as usize) == VirtPageNum::from(dst as usize + size) {
let page_table = PageTable::from_token(token);
let dst_pa = page_table
.translate_va(VirtAddr::from(dst as usize))
.unwrap();
unsafe {
let dst_ptr = dst_pa.0 as *mut u8;
core::slice::from_raw_parts_mut(dst_ptr, size)
.copy_from_slice(core::slice::from_raw_parts(src.as_ptr(), size));
*dst_ptr.add(size) = b'\0';
}
} else {
UserBuffer::new(translated_byte_buffer(token, dst as *mut u8, size))
.write(unsafe { core::slice::from_raw_parts(src.as_ptr(), size) });
let page_table = PageTable::from_token(token);
let dst_pa = page_table
.translate_va(VirtAddr::from(dst as usize + size))
.unwrap();
unsafe {
*(dst_pa.0 as *mut u8) = b'\0';
}
}
}