75 lines
2.6 KiB
Rust
75 lines
2.6 KiB
Rust
|
use core::marker::PhantomData;
|
||
|
|
use core::ptr;
|
||
|
|
|
||
|
|
use atomic_polyfill::{AtomicBool, Ordering};
|
||
|
|
|
||
|
|
use super::{raw, Spawner};
|
||
|
|
|
||
|
|
/// global atomic used to keep track of whether there is work to do since sev() is not available on RISCV
|
||
|
|
///
|
||
|
|
static SIGNAL_WORK_THREAD_MODE: AtomicBool = AtomicBool::new(false);
|
||
|
|
|
||
|
|
/// RISCV32 Executor
|
||
|
|
pub struct Executor {
|
||
|
|
inner: raw::Executor,
|
||
|
|
not_send: PhantomData<*mut ()>,
|
||
|
|
}
|
||
|
|
|
||
|
|
impl Executor {
|
||
|
|
/// Create a new Executor.
|
||
|
|
pub fn new() -> Self {
|
||
|
|
Self {
|
||
|
|
// use Signal_Work_Thread_Mode as substitute for local interrupt register
|
||
|
|
inner: raw::Executor::new(
|
||
|
|
|_| {
|
||
|
|
SIGNAL_WORK_THREAD_MODE.store(true, Ordering::SeqCst);
|
||
|
|
},
|
||
|
|
ptr::null_mut(),
|
||
|
|
),
|
||
|
|
not_send: PhantomData,
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/// Run the executor.
|
||
|
|
///
|
||
|
|
/// The `init` closure is called with a [`Spawner`] that spawns tasks on
|
||
|
|
/// this executor. Use it to spawn the initial task(s). After `init` returns,
|
||
|
|
/// the executor starts running the tasks.
|
||
|
|
///
|
||
|
|
/// To spawn more tasks later, you may keep copies of the [`Spawner`] (it is `Copy`),
|
||
|
|
/// for example by passing it as an argument to the initial tasks.
|
||
|
|
///
|
||
|
|
/// This function requires `&'static mut self`. This means you have to store the
|
||
|
|
/// Executor instance in a place where it'll live forever and grants you mutable
|
||
|
|
/// access. There's a few ways to do this:
|
||
|
|
///
|
||
|
|
/// - a [Forever](crate::util::Forever) (safe)
|
||
|
|
/// - a `static mut` (unsafe)
|
||
|
|
/// - a local variable in a function you know never returns (like `fn main() -> !`), upgrading its lifetime with `transmute`. (unsafe)
|
||
|
|
///
|
||
|
|
/// This function never returns.
|
||
|
|
pub fn run(&'static mut self, init: impl FnOnce(Spawner)) -> ! {
|
||
|
|
init(self.inner.spawner());
|
||
|
|
|
||
|
|
loop {
|
||
|
|
unsafe {
|
||
|
|
self.inner.poll();
|
||
|
|
// we do not care about race conditions between the load and store operations, interrupts
|
||
|
|
//will only set this value to true.
|
||
|
|
critical_section::with(|_| {
|
||
|
|
// if there is work to do, loop back to polling
|
||
|
|
// TODO can we relax this?
|
||
|
|
if SIGNAL_WORK_THREAD_MODE.load(Ordering::SeqCst) {
|
||
|
|
SIGNAL_WORK_THREAD_MODE.store(false, Ordering::SeqCst);
|
||
|
|
}
|
||
|
|
// if not, wait for interrupt
|
||
|
|
else {
|
||
|
|
core::arch::asm!("wfi");
|
||
|
|
}
|
||
|
|
});
|
||
|
|
// if an interrupt occurred while waiting, it will be serviced here
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|