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Implement CurrentTask

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This commit is contained in:
Ruihan Li
2024-11-03 23:11:58 +08:00
committed by Tate, Hongliang Tian
parent 51db2da151
commit 1469059888
4 changed files with 70 additions and 22 deletions
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17
ostd/src/task/processor.rs
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@ -1,6 +1,7 @@
// SPDX-License-Identifier: MPL-2.0
use alloc::sync::Arc;
use core::ptr::NonNull;
use super::{context_switch, Task, TaskContext};
use crate::cpu_local_cell;
@ -16,21 +17,11 @@ cpu_local_cell! {
static BOOTSTRAP_CONTEXT: TaskContext = TaskContext::new();
}
/// Retrieves a reference to the current task running on the processor.
/// Returns a pointer to the current task running on the processor.
///
/// It returns `None` if the function is called in the bootstrap context.
pub(super) fn current_task() -> Option<Arc<Task>> {
let ptr = CURRENT_TASK_PTR.load();
if ptr.is_null() {
return None;
}
// SAFETY: The pointer is set by `switch_to_task` and is guaranteed to be
// built with `Arc::into_raw`.
let restored = unsafe { Arc::from_raw(ptr) };
// To let the `CURRENT_TASK_PTR` still own the task, we clone and forget it
// to increment the reference count.
let _ = core::mem::ManuallyDrop::new(restored.clone());
Some(restored)
pub(super) fn current_task() -> Option<NonNull<Task>> {
NonNull::new(CURRENT_TASK_PTR.load().cast_mut())
}
/// Calls this function to switch to other task