report async errors upon kernel termination

Port of 4a6bea479a

Co-authored-by: Steve Fan <sf@m-labs.hk>
Reviewed-on: M-Labs/artiq-zynq#156
Co-authored-by: stevefan1999 <sf@m-labs.hk>
Co-committed-by: stevefan1999 <sf@m-labs.hk>

src/runtime/src/comms.rs

@@ -224,13 +224,14 @@ async fn handle_run_kernel(stream: Option<&TcpStream>, control: &Rc<RefCell<kern
                     }
                 }
             },
-            kernel::Message::KernelFinished => {
+            kernel::Message::KernelFinished(async_errors) => {
                 if let Some(stream) = stream {
                     write_header(stream, Reply::KernelFinished).await?;
+                    write_i8(stream, async_errors as i8).await?;
                 }
                 break;
             },
-            kernel::Message::KernelException(exception, backtrace) => {
+            kernel::Message::KernelException(exception, backtrace, async_errors) => {
                 match stream {
                     Some(stream) => {
                         // only send the exception data to host if there is host,
@@ -249,6 +250,7 @@ async fn handle_run_kernel(stream: Option<&TcpStream>, control: &Rc<RefCell<kern
                         for &addr in backtrace {
                             write_i32(stream, addr as i32).await?;
                         }
+                        write_i8(stream, async_errors as i8).await?;
                     },
                     None => {
                         error!("Uncaught kernel exception: {:?}", exception);

src/runtime/src/kernel/core1.rs

@@ -14,7 +14,7 @@ use libcortex_a9::{
 use libboard_zynq::{mpcore, gic};
 use libsupport_zynq::ram;
 use dyld::{self, Library};
-use crate::{eh_artiq, rtio};
+use crate::{eh_artiq, get_async_errors, rtio};
 use super::{
     api::resolve,
     rpc::rpc_send_async,
@@ -192,7 +192,8 @@ pub extern "C" fn main_core1() {
                     }
                 }
                 info!("kernel finished");
-                core1_tx.send(Message::KernelFinished);
+                let async_errors = unsafe { get_async_errors() };
+                core1_tx.send(Message::KernelFinished(async_errors));
             }
             _ => error!("Core1 received unexpected message: {:?}", message),
         }
@@ -216,7 +217,8 @@ pub fn terminate(exception: &'static eh_artiq::Exception<'static>, backtrace: &'
 
     {
         let core1_tx = unsafe { KERNEL_CHANNEL_1TO0.as_mut().unwrap() };
-        core1_tx.send(Message::KernelException(exception, &backtrace[..cursor]));
+        let errors = unsafe { get_async_errors() };
+        core1_tx.send(Message::KernelException(exception, &backtrace[..cursor], errors));
     }
     loop {}
 }

src/runtime/src/kernel/mod.rs

@@ -30,8 +30,8 @@ pub enum Message {
     LoadCompleted,
     LoadFailed,
     StartRequest,
-    KernelFinished,
+    KernelFinished(u8),
-    KernelException(&'static eh_artiq::Exception<'static>, &'static [usize]),
+    KernelException(&'static eh_artiq::Exception<'static>, &'static [usize], u8),
     RpcSend { is_async: bool, data: Vec<u8> },
     RpcRecvRequest(*mut ()),
     RpcRecvReply(Result<usize, RPCException>),

src/runtime/src/main.rs

@@ -42,6 +42,13 @@ mod analyzer;
 mod irq;
 mod i2c;
 
+static mut SEEN_ASYNC_ERRORS: u8 = 0;
+
+pub unsafe fn get_async_errors() -> u8 {
+    let errors = SEEN_ASYNC_ERRORS;
+    SEEN_ASYNC_ERRORS = 0;
+    errors
+}
 
 fn wait_for_async_rtio_error() -> nb::Result<(), Void> {
     unsafe {
@@ -70,6 +77,7 @@ async fn report_async_rtio_errors() {
                 error!("RTIO sequence error involving channel {}",
                        pl::csr::rtio_core::sequence_error_channel_read());
             }
+            SEEN_ASYNC_ERRORS = errors;
             pl::csr::rtio_core::async_error_write(errors);
         }
     }