Struct aster_frame::user::UserMode

pub struct UserMode<'a> { /* private fields */ }

Code execution in the user mode.

This type enables executing the code in user space from a task in the kernel space safely.

Here is a sample code on how to use UserMode.

use aster_frame::task::Task;

let current = Task::current();
let user_space = current.user_space()
    .expect("the current task is associated with a user space");
let mut user_mode = user_space.user_mode();
loop {
    // Execute in the user space until some interesting events occur.
    let return_reason = user_mode.execute(|| false);
    todo!("handle the event, e.g., syscall");
}

Implementations

impl<'a> UserMode<'a>

pub fn new(user_space: &'a Arc<UserSpace>) -> Self

Creates a new UserMode.

pub fn execute<F>(&mut self, has_kernel_event: F) -> ReturnReason

where F: FnMut() -> bool,

Starts executing in the user mode. Make sure current task is the task in UserMode.

The method returns for one of three possible reasons indicated by ReturnReason.

1. A system call is issued by the user space;
2. A CPU exception is triggered by the user space;
3. A kernel event is pending, as indicated by the given closure.

After handling whatever user or kernel events that cause the method to return and updating the user-mode CPU context, this method can be invoked again to go back to the user space.

pub fn context(&self) -> &UserContext

Returns an immutable reference the user-mode CPU context.

pub fn context_mut(&mut self) -> &mut UserContext

Returns a mutable reference the user-mode CPU context.

Trait Implementations

impl<'a> !Send for UserMode<'a>