rcore-tutorial/os/src/task/processor.rs
2022-04-30 16:04:58 +08:00

93 lines
3.2 KiB
Rust

//!Implementation of [`Processor`] and Intersection of control flow
use super::__switch;
use super::{fetch_task, TaskStatus};
use super::{TaskContext, TaskControlBlock};
use crate::sync::UPSafeCell;
use crate::trap::TrapContext;
use alloc::sync::Arc;
use lazy_static::*;
///Processor management structure
pub struct Processor {
///The task currently executing on the current processor
current: Option<Arc<TaskControlBlock>>,
///The basic control flow of each core, helping to select and switch process
idle_task_cx: TaskContext,
}
impl Processor {
///Create an empty Processor
pub fn new() -> Self {
Self {
current: None,
idle_task_cx: TaskContext::zero_init(),
}
}
///Get mutable reference to `idle_task_cx`
fn get_idle_task_cx_ptr(&mut self) -> *mut TaskContext {
&mut self.idle_task_cx as *mut _
}
///Get current task in moving semanteme
pub fn take_current(&mut self) -> Option<Arc<TaskControlBlock>> {
self.current.take()
}
///Get current task in cloning semanteme
pub fn current(&self) -> Option<Arc<TaskControlBlock>> {
self.current.as_ref().map(Arc::clone)
}
}
lazy_static! {
pub static ref PROCESSOR: UPSafeCell<Processor> = unsafe { UPSafeCell::new(Processor::new()) };
}
///The main part of process execution and scheduling
///Loop `fetch_task` to get the process that needs to run, and switch the process through `__switch`
pub fn run_tasks() {
loop {
let mut processor = PROCESSOR.exclusive_access();
if let Some(task) = fetch_task() {
let idle_task_cx_ptr = processor.get_idle_task_cx_ptr();
// access coming task TCB exclusively
let mut task_inner = task.inner_exclusive_access();
let next_task_cx_ptr = &task_inner.task_cx as *const TaskContext;
task_inner.task_status = TaskStatus::Running;
drop(task_inner);
// release coming task TCB manually
processor.current = Some(task);
// release processor manually
drop(processor);
unsafe {
__switch(idle_task_cx_ptr, next_task_cx_ptr);
}
}
}
}
///Take the current task,leaving a None in its place
pub fn take_current_task() -> Option<Arc<TaskControlBlock>> {
PROCESSOR.exclusive_access().take_current()
}
///Get running task
pub fn current_task() -> Option<Arc<TaskControlBlock>> {
PROCESSOR.exclusive_access().current()
}
///Get token of the address space of current task
pub fn current_user_token() -> usize {
let task = current_task().unwrap();
let token = task.inner_exclusive_access().get_user_token();
token
}
///Get the mutable reference to trap context of current task
pub fn current_trap_cx() -> &'static mut TrapContext {
current_task()
.unwrap()
.inner_exclusive_access()
.get_trap_cx()
}
///Return to idle control flow for new scheduling
pub fn schedule(switched_task_cx_ptr: *mut TaskContext) {
let mut processor = PROCESSOR.exclusive_access();
let idle_task_cx_ptr = processor.get_idle_task_cx_ptr();
drop(processor);
unsafe {
__switch(switched_task_cx_ptr, idle_task_cx_ptr);
}
}