36 lines
1005 B
Rust
36 lines
1005 B
Rust
use core::cell::UnsafeCell;
|
|
use core::mem::MaybeUninit;
|
|
use core::sync::atomic::{AtomicBool, Ordering};
|
|
|
|
pub struct KernelCell<T> {
|
|
initialized: AtomicBool,
|
|
inner: UnsafeCell<MaybeUninit<T>>,
|
|
}
|
|
|
|
// Single-core: no concurrent access. Initialized once before traps are enabled.
|
|
unsafe impl<T> Sync for KernelCell<T> {}
|
|
|
|
impl<T> KernelCell<T> {
|
|
pub const fn uninit() -> Self {
|
|
Self {
|
|
initialized: AtomicBool::new(false),
|
|
inner: UnsafeCell::new(MaybeUninit::uninit()),
|
|
}
|
|
}
|
|
|
|
pub fn init(&self, value: T) {
|
|
unsafe { (*self.inner.get()).write(value) };
|
|
self.initialized.store(true, Ordering::Release);
|
|
}
|
|
|
|
pub fn get(&self) -> &T {
|
|
debug_assert!(self.initialized.load(Ordering::Acquire));
|
|
unsafe { (*self.inner.get()).assume_init_ref() }
|
|
}
|
|
|
|
pub fn get_mut(&self) -> &mut T {
|
|
debug_assert!(self.initialized.load(Ordering::Acquire));
|
|
unsafe { (*self.inner.get()).assume_init_mut() }
|
|
}
|
|
}
|