68 lines
1.9 KiB
Rust
68 lines
1.9 KiB
Rust
use core::{
|
|
ops::{Deref, DerefMut},
|
|
mem::{align_of, size_of},
|
|
};
|
|
use alloc::alloc::{dealloc, Layout, LayoutErr};
|
|
use crate::mmu::{L1_PAGE_SIZE, L1Table};
|
|
|
|
pub struct UncachedSlice<T: 'static> {
|
|
layout: Layout,
|
|
slice: &'static mut [T],
|
|
}
|
|
|
|
impl<T> UncachedSlice<T> {
|
|
/// allocates in chunks of 1 MB
|
|
pub fn new<F: Fn() -> T>(len: usize, default: F) -> Result<Self, LayoutErr> {
|
|
// round to full pages
|
|
let size = ((len * size_of::<T>() - 1) | (L1_PAGE_SIZE - 1)) + 1;
|
|
let align = align_of::<T>()
|
|
.max(L1_PAGE_SIZE);
|
|
let layout = Layout::from_size_align(size, align)?;
|
|
let ptr = unsafe { alloc::alloc::alloc(layout).cast::<T>() };
|
|
let start = ptr as usize;
|
|
assert_eq!(start & (L1_PAGE_SIZE - 1), 0);
|
|
|
|
for page_start in (start..(start + size)).step_by(L1_PAGE_SIZE) {
|
|
// non-shareable device
|
|
L1Table::get()
|
|
.update(page_start as *const (), |l1_section| {
|
|
l1_section.tex = 0b10;
|
|
l1_section.cacheable = true;
|
|
l1_section.bufferable = false;
|
|
});
|
|
}
|
|
|
|
let slice = unsafe { core::slice::from_raw_parts_mut(ptr, len) };
|
|
// verify size
|
|
assert!(unsafe { slice.get_unchecked(len) } as *const _ as usize <= start + size);
|
|
// initialize
|
|
for e in slice.iter_mut() {
|
|
*e = default();
|
|
}
|
|
Ok(UncachedSlice { layout, slice })
|
|
}
|
|
}
|
|
|
|
/// Does not yet mark the pages cachable again
|
|
impl<T> Drop for UncachedSlice<T> {
|
|
fn drop(&mut self) {
|
|
unsafe {
|
|
dealloc(self.slice.as_mut_ptr() as *mut _ as *mut u8, self.layout);
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<T> Deref for UncachedSlice<T> {
|
|
type Target = [T];
|
|
|
|
fn deref(&self) -> &Self::Target {
|
|
self.slice
|
|
}
|
|
}
|
|
|
|
impl<T> DerefMut for UncachedSlice<T> {
|
|
fn deref_mut(&mut self) -> &mut Self::Target {
|
|
self.slice
|
|
}
|
|
}
|