ax-runtime 0.12.0

Runtime library of ArceOS
Documentation 
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//! Shared IPI transport for scheduler doorbells and synchronous hard calls.

#[cfg(feature = "ipi")]
pub(crate) unsafe fn run_on_cpu_sync(
    cpu: usize,
    f: unsafe fn(*mut ()),
    arg: *mut (),
) -> Result<(), ax_hal::irq::IrqError> {
    // SAFETY: the caller supplies the hard-call ABI and lifetime required by
    // ax-ipi; this adapter only forwards the typed platform hook.
    unsafe { ax_ipi::call_on_cpu(ax_hal::irq::CpuId(cpu), f, arg) }
}

#[cfg(any(feature = "ipi", feature = "wake-ipi", test))]
fn dispatch_scheduler_doorbell(
    scheduler_work_pending: impl FnOnce() -> bool,
    publish_scheduler_work: impl FnOnce(),
) {
    if scheduler_work_pending() {
        publish_scheduler_work();
    }
}

#[cfg(any(feature = "ipi", feature = "wake-ipi"))]
fn local_scheduler_work_pending() -> bool {
    let pending = crate::task::runtime::cpu::current_cpu_needs_resched()
        .expect("IPI delivery requires an online scheduler CPU");
    #[cfg(feature = "qperf-metrics")]
    if pending {
        crate::thread::record_scheduler_ipi_consume();
    }
    pending
}

#[cfg(feature = "ipi")]
pub(crate) fn irq_handler(_ctx: ax_hal::irq::IrqContext) -> ax_hal::irq::IrqReturn {
    ax_ipi::claim_current_delivery();
    dispatch_scheduler_doorbell(local_scheduler_work_pending, || {
        let _self_serviced = crate::guard::publish_local_scheduler_work();
    });
    ax_ipi::drain_hard_calls()
        .unwrap_or_else(|error| panic!("failed to continue hard-call draining: {error:?}"));
    ax_hal::irq::IrqReturn::Handled
}

#[cfg(all(feature = "wake-ipi", not(feature = "ipi")))]
pub(crate) fn irq_handler(_ctx: ax_hal::irq::IrqContext) -> ax_hal::irq::IrqReturn {
    ax_ipi::claim_current_delivery();
    dispatch_scheduler_doorbell(local_scheduler_work_pending, || {
        let _self_serviced = crate::guard::publish_local_scheduler_work();
    });
    ax_hal::irq::IrqReturn::Handled
}

#[cfg(test)]
mod tests {
    use core::cell::RefCell;

    #[test]
    fn shared_ipi_dispatch_publishes_pending_scheduler_work() {
        let events = RefCell::new(alloc::vec::Vec::new());

        super::dispatch_scheduler_doorbell(
            || {
                events.borrow_mut().push("consume");
                true
            },
            || events.borrow_mut().push("publish"),
        );

        assert_eq!(*events.borrow(), ["consume", "publish"]);
    }

    #[test]
    fn unrelated_shared_ipi_only_checks_the_scheduler_doorbell() {
        let events = RefCell::new(alloc::vec::Vec::new());

        super::dispatch_scheduler_doorbell(
            || {
                events.borrow_mut().push("consume");
                false
            },
            || events.borrow_mut().push("publish"),
        );

        assert_eq!(*events.borrow(), ["consume"]);
    }
}