moros/src/kernel/allocator.rs

120 lines
3.2 KiB
Rust

use crate::kernel;
use alloc::slice::SliceIndex;
use alloc::sync::Arc;
use alloc::vec::Vec;
use core::ops::{Index, IndexMut};
use linked_list_allocator::LockedHeap;
use spin::Mutex;
use x86_64::structures::paging::mapper::MapToError;
use x86_64::structures::paging::{FrameAllocator, Mapper, Page, PageTableFlags, Size4KiB};
use x86_64::VirtAddr;
pub const HEAP_START: usize = 0x_4444_4444_0000;
pub const HEAP_SIZE: usize = 1 << 20; // 1 MB
#[global_allocator]
static ALLOCATOR: LockedHeap = LockedHeap::empty();
pub fn init_heap(mapper: &mut impl Mapper<Size4KiB>, frame_allocator: &mut impl FrameAllocator<Size4KiB>) -> Result<(), MapToError<Size4KiB>> {
let page_range = {
let heap_start = VirtAddr::new(HEAP_START as u64);
let heap_end = heap_start + HEAP_SIZE - 1u64;
let heap_start_page = Page::containing_address(heap_start);
let heap_end_page = Page::containing_address(heap_end);
Page::range_inclusive(heap_start_page, heap_end_page)
};
for page in page_range {
let frame = frame_allocator.allocate_frame().ok_or(MapToError::FrameAllocationFailed)?;
let flags = PageTableFlags::PRESENT | PageTableFlags::WRITABLE;
unsafe {
mapper.map_to(page, frame, flags, frame_allocator)?.flush();
}
}
unsafe {
ALLOCATOR.lock().init(HEAP_START, HEAP_SIZE);
}
Ok(())
}
#[derive(Clone)]
pub struct PhysBuf {
buf: Arc<Mutex<Vec<u8>>>,
}
impl PhysBuf {
pub fn new(len: usize) -> Self {
let mut vec: Vec<u8> = Vec::with_capacity(len);
vec.resize(len, 0);
Self::from(vec)
}
// Realloc vec until it uses a chunk of contiguous physical memory
fn from(vec: Vec<u8>) -> Self {
let buffer_len = vec.len() - 1;
let memory_len = phys_addr(&vec[buffer_len]) - phys_addr(&vec[0]);
if buffer_len == memory_len as usize {
Self { buf: Arc::new(Mutex::new(vec)) }
} else {
Self::from(vec.clone())
}
}
pub fn addr(&self) -> u64 {
phys_addr(&self.buf.lock()[0])
}
}
fn phys_addr(ptr: &u8) -> u64 {
let rx_ptr = ptr as *const u8;
let virt_addr = VirtAddr::new(rx_ptr as u64);
let phys_addr = kernel::mem::virt_to_phys(virt_addr).unwrap();
phys_addr.as_u64()
}
impl<I: SliceIndex<[u8]>> Index<I> for PhysBuf {
type Output = I::Output;
#[inline]
fn index(&self, index: I) -> &Self::Output {
Index::index(&**self, index)
}
}
impl<I: SliceIndex<[u8]>> IndexMut<I> for PhysBuf {
#[inline]
fn index_mut(&mut self, index: I) -> &mut Self::Output {
IndexMut::index_mut(&mut **self, index)
}
}
impl core::ops::Deref for PhysBuf {
type Target = [u8];
fn deref(&self) -> &[u8] {
let vec = self.buf.lock();
unsafe { alloc::slice::from_raw_parts(vec.as_ptr(), vec.len()) }
}
}
impl core::ops::DerefMut for PhysBuf {
fn deref_mut(&mut self) -> &mut [u8] {
let mut vec = self.buf.lock();
unsafe { alloc::slice::from_raw_parts_mut(vec.as_mut_ptr(), vec.len()) }
}
}
pub fn size() -> usize {
ALLOCATOR.lock().size()
}
pub fn used() -> usize {
ALLOCATOR.lock().used()
}
pub fn free() -> usize {
ALLOCATOR.lock().free()
}