master: drtioaux:

- support async flag
- source in packets
- rerouting packets

src/libboard_artiq/src/drtioaux_proto.rs

@@ -5,7 +5,7 @@ use io::proto::{ProtoRead, ProtoWrite};
 // used by satellite -> master analyzer, subkernel exceptions
 pub const SAT_PAYLOAD_MAX_SIZE: usize  = /*max size*/512 - /*CRC*/4 - /*packet ID*/1 - /*last*/1 - /*length*/2;
 // used by DDMA, subkernel program data (need to provide extra ID and destination)
-pub const MASTER_PAYLOAD_MAX_SIZE: usize = SAT_PAYLOAD_MAX_SIZE - /*destination*/1 - /*ID*/4;
+pub const MASTER_PAYLOAD_MAX_SIZE: usize = SAT_PAYLOAD_MAX_SIZE - /*source*/1 - /*destination*/1 - /*ID*/4;
 
 #[derive(Debug)]
 pub enum Error {
@@ -89,6 +89,8 @@ pub enum Packet {
     RoutingSetRank {
         rank: u8,
     },
+    RoutingRetrievePackets,
+    RoutingNoPackets,
     RoutingAck,
 
     MonitorRequest {
@@ -197,6 +199,7 @@ pub enum Packet {
     },
 
     DmaAddTraceRequest {
+        source: u8,
         destination: u8,
         id: u32,
         status: PayloadStatus,
@@ -204,24 +207,30 @@ pub enum Packet {
         trace: [u8; MASTER_PAYLOAD_MAX_SIZE],
     },
     DmaAddTraceReply {
+        destination: u8,
         succeeded: bool,
     },
     DmaRemoveTraceRequest {
+        source: u8,
         destination: u8,
         id: u32,
     },
     DmaRemoveTraceReply {
+        destination: u8,
         succeeded: bool,
     },
     DmaPlaybackRequest {
+        source: u8,
         destination: u8,
         id: u32,
         timestamp: u64,
     },
     DmaPlaybackReply {
+        destination: u8,
         succeeded: bool,
     },
     DmaPlaybackStatus {
+        source: u8,
         destination: u8,
         id: u32,
         error: u8,
@@ -240,22 +249,20 @@ pub enum Packet {
         succeeded: bool,
     },
     SubkernelLoadRunRequest {
+        source: u8,
         destination: u8,
         id: u32,
         run: bool,
     },
     SubkernelLoadRunReply {
-        succeeded: bool,
-    },
-    SubkernelStopRequest {
         destination: u8,
-    },
-    SubkernelStopReply {
         succeeded: bool,
     },
     SubkernelFinished {
+        destination: u8,
         id: u32,
         with_exception: bool,
+        exception_src: u8,
     },
     SubkernelExceptionRequest {
         destination: u8,
@@ -266,6 +273,7 @@ pub enum Packet {
         data: [u8; SAT_PAYLOAD_MAX_SIZE],
     },
     SubkernelMessage {
+        source: u8,
         destination: u8,
         id: u32,
         status: PayloadStatus,
@@ -315,6 +323,8 @@ impl Packet {
                 rank: reader.read_u8()?,
             },
             0x32 => Packet::RoutingAck,
+            0x33 => Packet::RoutingRetrievePackets,
+            0x34 => Packet::RoutingNoPackets,
 
             0x40 => Packet::MonitorRequest {
                 destination: reader.read_u8()?,
@@ -429,39 +439,47 @@ impl Packet {
             }
 
             0xb0 => {
+                let source = reader.read_u8()?;
                 let destination = reader.read_u8()?;
                 let id = reader.read_u32()?;
-                let status = PayloadStatus::from(reader.read_u8()?);
+                let status = reader.read_u8()?;
                 let length = reader.read_u16()?;
                 let mut trace: [u8; MASTER_PAYLOAD_MAX_SIZE] = [0; MASTER_PAYLOAD_MAX_SIZE];
                 reader.read_exact(&mut trace[0..length as usize])?;
                 Packet::DmaAddTraceRequest {
+                    source: source,
                     destination: destination,
                     id: id,
-                    status: status,
+                    status: PayloadStatus::from(status),
                     length: length as u16,
                     trace: trace,
                 }
             }
             0xb1 => Packet::DmaAddTraceReply {
+                destination: reader.read_u8()?,
                 succeeded: reader.read_bool()?,
             },
             0xb2 => Packet::DmaRemoveTraceRequest {
+                source: reader.read_u8()?,
                 destination: reader.read_u8()?,
                 id: reader.read_u32()?,
             },
             0xb3 => Packet::DmaRemoveTraceReply {
+                destination: reader.read_u8()?,
                 succeeded: reader.read_bool()?,
             },
             0xb4 => Packet::DmaPlaybackRequest {
+                source: reader.read_u8()?,
                 destination: reader.read_u8()?,
                 id: reader.read_u32()?,
                 timestamp: reader.read_u64()?,
             },
             0xb5 => Packet::DmaPlaybackReply {
+                destination: reader.read_u8()?,
                 succeeded: reader.read_bool()?,
             },
             0xb6 => Packet::DmaPlaybackStatus {
+                source: reader.read_u8()?,
                 destination: reader.read_u8()?,
                 id: reader.read_u32()?,
                 error: reader.read_u8()?,
@@ -488,22 +506,20 @@ impl Packet {
                 succeeded: reader.read_bool()?,
             },
             0xc4 => Packet::SubkernelLoadRunRequest {
+                source: reader.read_u8()?,
                 destination: reader.read_u8()?,
                 id: reader.read_u32()?,
                 run: reader.read_bool()?,
             },
             0xc5 => Packet::SubkernelLoadRunReply {
-                succeeded: reader.read_bool()?,
-            },
-            0xc6 => Packet::SubkernelStopRequest {
                 destination: reader.read_u8()?,
-            },
-            0xc7 => Packet::SubkernelStopReply {
                 succeeded: reader.read_bool()?,
             },
             0xc8 => Packet::SubkernelFinished {
+                destination: reader.read_u8()?,
                 id: reader.read_u32()?,
                 with_exception: reader.read_bool()?,
+                exception_src: reader.read_u8()?,
             },
             0xc9 => Packet::SubkernelExceptionRequest {
                 destination: reader.read_u8()?,
@@ -520,16 +536,18 @@ impl Packet {
                 }
             }
             0xcb => {
+                let source = reader.read_u8()?;
                 let destination = reader.read_u8()?;
                 let id = reader.read_u32()?;
-                let status = PayloadStatus::from(reader.read_u8()?);
+                let status = reader.read_u8()?;
                 let length = reader.read_u16()?;
                 let mut data: [u8; MASTER_PAYLOAD_MAX_SIZE] = [0; MASTER_PAYLOAD_MAX_SIZE];
                 reader.read_exact(&mut data[0..length as usize])?;
                 Packet::SubkernelMessage {
+                    source: source,
                     destination: destination,
                     id: id,
-                    status: status,
+                    status: PayloadStatus::from(status),
                     length: length as u16,
                     data: data,
                 }
@@ -580,6 +598,8 @@ impl Packet {
                 writer.write_u8(rank)?;
             }
             Packet::RoutingAck => writer.write_u8(0x32)?,
+            Packet::RoutingRetrievePackets => writer.write_u8(0x33)?,
+            Packet::RoutingNoPackets => writer.write_u8(0x34)?,
 
             Packet::MonitorRequest {
                 destination,
@@ -751,6 +771,7 @@ impl Packet {
             }
 
             Packet::DmaAddTraceRequest {
+                source,
                 destination,
                 id,
                 status,
@@ -758,6 +779,7 @@ impl Packet {
                 length,
             } => {
                 writer.write_u8(0xb0)?;
+                writer.write_u8(source)?;
                 writer.write_u8(destination)?;
                 writer.write_u32(id)?;
                 writer.write_u8(status as u8)?;
@@ -766,34 +788,45 @@ impl Packet {
                 writer.write_u16(length)?;
                 writer.write_all(&trace[0..length as usize])?;
             }
-            Packet::DmaAddTraceReply { succeeded } => {
+            Packet::DmaAddTraceReply { destination, succeeded } => {
                 writer.write_u8(0xb1)?;
+                writer.write_u8(destination)?;
                 writer.write_bool(succeeded)?;
             }
-            Packet::DmaRemoveTraceRequest { destination, id } => {
+            Packet::DmaRemoveTraceRequest {
+                source,
+                destination,
+                id,
+            } => {
                 writer.write_u8(0xb2)?;
+                writer.write_u8(source)?;
                 writer.write_u8(destination)?;
                 writer.write_u32(id)?;
             }
-            Packet::DmaRemoveTraceReply { succeeded } => {
+            Packet::DmaRemoveTraceReply { destination, succeeded } => {
                 writer.write_u8(0xb3)?;
+                writer.write_u8(destination)?;
                 writer.write_bool(succeeded)?;
             }
             Packet::DmaPlaybackRequest {
+                source,
                 destination,
                 id,
                 timestamp,
             } => {
                 writer.write_u8(0xb4)?;
+                writer.write_u8(source)?;
                 writer.write_u8(destination)?;
                 writer.write_u32(id)?;
                 writer.write_u64(timestamp)?;
             }
-            Packet::DmaPlaybackReply { succeeded } => {
+            Packet::DmaPlaybackReply { destination, succeeded } => {
                 writer.write_u8(0xb5)?;
+                writer.write_u8(destination)?;
                 writer.write_bool(succeeded)?;
             }
             Packet::DmaPlaybackStatus {
+                source,
                 destination,
                 id,
                 error,
@@ -801,6 +834,7 @@ impl Packet {
                 timestamp,
             } => {
                 writer.write_u8(0xb6)?;
+                writer.write_u8(source)?;
                 writer.write_u8(destination)?;
                 writer.write_u32(id)?;
                 writer.write_u8(error)?;
@@ -826,28 +860,34 @@ impl Packet {
                 writer.write_u8(0xc1)?;
                 writer.write_bool(succeeded)?;
             }
-            Packet::SubkernelLoadRunRequest { destination, id, run } => {
+            Packet::SubkernelLoadRunRequest {
+                source,
+                destination,
+                id,
+                run,
+            } => {
                 writer.write_u8(0xc4)?;
+                writer.write_u8(source)?;
                 writer.write_u8(destination)?;
                 writer.write_u32(id)?;
                 writer.write_bool(run)?;
             }
-            Packet::SubkernelLoadRunReply { succeeded } => {
+            Packet::SubkernelLoadRunReply { destination, succeeded } => {
                 writer.write_u8(0xc5)?;
-                writer.write_bool(succeeded)?;
-            }
-            Packet::SubkernelStopRequest { destination } => {
-                writer.write_u8(0xc6)?;
                 writer.write_u8(destination)?;
-            }
-            Packet::SubkernelStopReply { succeeded } => {
-                writer.write_u8(0xc7)?;
                 writer.write_bool(succeeded)?;
             }
-            Packet::SubkernelFinished { id, with_exception } => {
+            Packet::SubkernelFinished {
+                destination,
+                id,
+                with_exception,
+                exception_src,
+            } => {
                 writer.write_u8(0xc8)?;
+                writer.write_u8(destination)?;
                 writer.write_u32(id)?;
                 writer.write_bool(with_exception)?;
+                writer.write_u8(exception_src)?;
             }
             Packet::SubkernelExceptionRequest { destination } => {
                 writer.write_u8(0xc9)?;
@@ -860,6 +900,7 @@ impl Packet {
                 writer.write_all(&data[0..length as usize])?;
             }
             Packet::SubkernelMessage {
+                source,
                 destination,
                 id,
                 status,
@@ -867,6 +908,7 @@ impl Packet {
                 length,
             } => {
                 writer.write_u8(0xcb)?;
+                writer.write_u8(source)?;
                 writer.write_u8(destination)?;
                 writer.write_u32(id)?;
                 writer.write_u8(status as u8)?;

src/libksupport/src/kernel/mod.rs

@@ -77,6 +77,7 @@ pub enum Message {
     #[cfg(has_drtio)]
     SubkernelLoadRunRequest {
         id: u32,
+        destination: u8,
         run: bool,
     },
     #[cfg(has_drtio)]
@@ -95,6 +96,7 @@ pub enum Message {
     #[cfg(has_drtio)]
     SubkernelMsgSend {
         id: u32,
+        destination: Option<u8>,
         data: Vec<u8>,
     },
     #[cfg(has_drtio)]

src/libksupport/src/kernel/subkernel.rs

@@ -5,12 +5,16 @@ use cslice::CSlice;
 use super::{Message, SubkernelStatus, KERNEL_CHANNEL_0TO1, KERNEL_CHANNEL_1TO0};
 use crate::{artiq_raise, rpc::send_args};
 
-pub extern "C" fn load_run(id: u32, run: bool) {
+pub extern "C" fn load_run(id: u32, destination: u8, run: bool) {
     unsafe {
         KERNEL_CHANNEL_1TO0
             .as_mut()
             .unwrap()
-            .send(Message::SubkernelLoadRunRequest { id: id, run: run });
+            .send(Message::SubkernelLoadRunRequest {
+                id: id,
+                destination: destination,
+                run: run,
+            });
     }
     match unsafe { KERNEL_CHANNEL_0TO1.as_mut().unwrap() }.recv() {
         Message::SubkernelLoadRunReply { succeeded: true } => (),
@@ -51,7 +55,14 @@ pub extern "C" fn await_finish(id: u32, timeout: u64) {
     }
 }
 
-pub extern "C" fn send_message(id: u32, count: u8, tag: &CSlice<u8>, data: *const *const ()) {
+pub extern "C" fn send_message(
+    id: u32,
+    is_return: bool,
+    destination: u8,
+    count: u8,
+    tag: &CSlice<u8>,
+    data: *const *const (),
+) {
     let mut buffer = Vec::<u8>::new();
     send_args(&mut buffer, 0, tag.as_ref(), data, false).expect("RPC encoding failed");
     // overwrite service tag, include how many tags are in the message
@@ -59,6 +70,7 @@ pub extern "C" fn send_message(id: u32, count: u8, tag: &CSlice<u8>, data: *cons
     unsafe {
         KERNEL_CHANNEL_1TO0.as_mut().unwrap().send(Message::SubkernelMsgSend {
             id: id,
+            destination: if is_return { None } else { Some(destination) },
             data: buffer[3..].to_vec(),
         });
     }

src/runtime/src/comms.rs

@@ -401,7 +401,11 @@ async fn handle_run_kernel(
                 control.borrow_mut().tx.async_send(reply).await;
             }
             #[cfg(has_drtio)]
-            kernel::Message::SubkernelLoadRunRequest { id, run } => {
+            kernel::Message::SubkernelLoadRunRequest {
+                id,
+                destination: _,
+                run,
+            } => {
                 let succeeded = match subkernel::load(aux_mutex, routing_table, timer, id, run).await {
                     Ok(()) => true,
                     Err(e) => {
@@ -447,7 +451,11 @@ async fn handle_run_kernel(
                     .await;
             }
             #[cfg(has_drtio)]
-            kernel::Message::SubkernelMsgSend { id, data } => {
+            kernel::Message::SubkernelMsgSend {
+                id,
+                destination: _,
+                data,
+            } => {
                 let res = subkernel::message_send(aux_mutex, routing_table, timer, id, data).await;
                 match res {
                     Ok(_) => (),

src/runtime/src/rtio_mgt.rs

@@ -43,26 +43,44 @@ pub mod drtio {
         unsafe { (csr::DRTIO[linkno].rx_up_read)() == 1 }
     }
 
-    async fn process_async_packets(aux_mutex: &Mutex<bool>, linkno: u8, packet: Packet) -> Option<Packet> {
+    async fn link_has_async_ready(linkno: u8) -> bool {
-        // returns None if an async packet has been consumed
+        let linkno = linkno as usize;
+        let async_ready;
+        unsafe {
+            async_ready = (csr::DRTIO[linkno].async_messages_ready_read)() == 1;
+            (csr::DRTIO[linkno].async_messages_ready_write)(1);
+        }
+        async_ready
+    }
+
+    async fn process_async_packets(aux_mutex: &Mutex<bool>, linkno: u8, routing_table: &drtio_routing::RoutingTable, timer: GlobalTimer) {
+        if link_has_async_ready(linkno).await {
+            loop {
+                let reply = aux_transact(aux_mutex, linkno, &Packet::RoutingRetrievePackets, timer).await;
+                if let Ok(packet) = reply {
                     match packet {
                         Packet::DmaPlaybackStatus {
                             id,
-                destination,
+                            source,
+                            destination: 0,
                             error,
                             channel,
                             timestamp,
                         } => {
-                remote_dma::playback_done(id, destination, error, channel, timestamp).await;
+                            remote_dma::playback_done(id, source, error, channel, timestamp).await;
-                None
                         }
-            Packet::SubkernelFinished { id, with_exception } => {
+                        Packet::SubkernelFinished {
-                subkernel::subkernel_finished(id, with_exception).await;
+                            id,
-                None
+                            destination: 0,
+                            with_exception,
+                            exception_src,
+                        } => {
+                            subkernel::subkernel_finished(id, with_exception, exception_src).await;
                         }
                         Packet::SubkernelMessage {
                             id,
-                destination: from,
+                            source,
+                            destination: 0,
                             status,
                             length,
                             data,
@@ -70,12 +88,52 @@ pub mod drtio {
                             subkernel::message_handle_incoming(id, status, length as usize, &data).await;
                             // acknowledge receiving part of the message
                             let _lock = aux_mutex.async_lock().await;
-                drtioaux_async::send(linkno, &Packet::SubkernelMessageAck { destination: from })
+                            drtioaux_async::send(linkno, &Packet::SubkernelMessageAck { destination: source })
                                 .await
                                 .unwrap();
-                None
+                            let mut countdown = timer.countdown();
+                            // give the satellites some time to process
+                            delay(&mut countdown, Milliseconds(10)).await;
+                        }
+                        // routable packets
+                        Packet::DmaAddTraceRequest { destination, .. }
+                        | Packet::DmaAddTraceReply { destination, .. }
+                        | Packet::DmaRemoveTraceRequest { destination, .. }
+                        | Packet::DmaRemoveTraceReply { destination, .. }
+                        | Packet::DmaPlaybackRequest { destination, .. }
+                        | Packet::DmaPlaybackReply { destination, .. }
+                        | Packet::SubkernelLoadRunRequest { destination, .. }
+                        | Packet::SubkernelLoadRunReply { destination, .. }
+                        | Packet::SubkernelMessage { destination, .. }
+                        | Packet::SubkernelMessageAck { destination, .. }
+                        | Packet::DmaPlaybackStatus { destination, .. }
+                        | Packet::SubkernelFinished { destination, .. } => {
+                            let dest_link = routing_table.0[destination as usize][0] - 1;
+                            if dest_link == linkno {
+                                warn!(
+                                    "[LINK#{}] Re-routed packet would return to the same link, dropping: {:?}",
+                                    linkno, packet
+                                );
+                            } else if destination == 0 {
+                                warn!("[LINK#{}] Received invalid routable packet: {:?}", linkno, packet)
+                            } else {
+                                drtioaux_async::send(dest_link, &packet).await.unwrap();
+                            }
+                        }
+
+                        Packet::RoutingNoPackets => break,
+
+                        other => warn!("[LINK#{}] Received an unroutable packet: {:?}", linkno, other),
+                    }
+                } else {
+                    warn!(
+                        "[LINK#{}] Error handling async packets ({})",
+                        linkno,
+                        reply.unwrap_err()
+                    );
+                    return;
+                }
             }
-            other => Some(other),
         }
     }
 
@@ -210,11 +268,7 @@ pub mod drtio {
     async fn process_unsolicited_aux(aux_mutex: &Rc<Mutex<bool>>, linkno: u8) {
         let _lock = aux_mutex.async_lock().await;
         match drtioaux_async::recv(linkno).await {
-            Ok(Some(packet)) => {
+            Ok(Some(packet)) => warn!("[LINK#{}] unsolicited aux packet: {:?}", linkno, packet),
-                if let Some(packet) = process_async_packets(aux_mutex, linkno, packet).await {
-                    warn!("[LINK#{}] unsolicited aux packet: {:?}", linkno, packet);
-                }
-            }
             Ok(None) => (),
             Err(_) => warn!("[LINK#{}] aux packet error", linkno),
         }
@@ -283,7 +337,6 @@ pub mod drtio {
                 let linkno = hop - 1;
                 if destination_up(up_destinations, destination).await {
                     if up_links[linkno as usize] {
-                        loop {
                         let reply = aux_transact(
                             aux_mutex,
                             linkno,
@@ -296,13 +349,7 @@ pub mod drtio {
                         match reply {
                             Ok(Packet::DestinationDownReply) => {
                                 destination_set_up(routing_table, up_destinations, destination, false).await;
-                                    remote_dma::destination_changed(
+                                remote_dma::destination_changed(aux_mutex, routing_table, timer, destination, false)
-                                        aux_mutex,
-                                        routing_table,
-                                        timer,
-                                        destination,
-                                        false,
-                                    )
                                     .await;
                                 subkernel::destination_changed(aux_mutex, routing_table, timer, destination, false)
                                     .await;
@@ -335,16 +382,9 @@ pub mod drtio {
                                 );
                                 unsafe { SEEN_ASYNC_ERRORS |= ASYNC_ERROR_BUSY };
                             }
-                                Ok(packet) => match process_async_packets(aux_mutex, linkno, packet).await {
+                            Ok(packet) => error!("[DEST#{}] received unexpected aux packet: {:?}", destination, packet),
-                                    Some(packet) => {
-                                        error!("[DEST#{}] received unexpected aux packet: {:?}", destination, packet)
-                                    }
-                                    None => continue,
-                                },
                             Err(e) => error!("[DEST#{}] communication failed ({})", destination, e),
                         }
-                            break;
-                        }
                     } else {
                         destination_set_up(routing_table, up_destinations, destination, false).await;
                         remote_dma::destination_changed(aux_mutex, routing_table, timer, destination, false).await;
@@ -393,6 +433,7 @@ pub mod drtio {
                 if up_links[linkno as usize] {
                     /* link was previously up */
                     if link_rx_up(linkno).await {
+                        process_async_packets(aux_mutex, linkno, routing_table, timer).await;
                         process_unsolicited_aux(aux_mutex, linkno).await;
                         process_local_errors(linkno).await;
                     } else {
@@ -504,14 +545,21 @@ pub mod drtio {
             trace,
             |slice, status, len| Packet::DmaAddTraceRequest {
                 id: id,
+                source: 0,
                 destination: destination,
                 status: status,
                 length: len as u16,
                 trace: *slice,
             },
             |reply| match reply {
-                Packet::DmaAddTraceReply { succeeded: true } => Ok(()),
+                Packet::DmaAddTraceReply {
-                Packet::DmaAddTraceReply { succeeded: false } => Err("error adding trace on satellite"),
+                    destination: 0,
+                    succeeded: true,
+                } => Ok(()),
+                Packet::DmaAddTraceReply {
+                    destination: 0,
+                    succeeded: false,
+                } => Err("error adding trace on satellite"),
                 _ => Err("adding DMA trace failed, unexpected aux packet"),
             },
         )
@@ -531,14 +579,21 @@ pub mod drtio {
             linkno,
             &Packet::DmaRemoveTraceRequest {
                 id: id,
+                source: 0,
                 destination: destination,
             },
             timer,
         )
         .await;
         match reply {
-            Ok(Packet::DmaRemoveTraceReply { succeeded: true }) => Ok(()),
+            Ok(Packet::DmaRemoveTraceReply {
-            Ok(Packet::DmaRemoveTraceReply { succeeded: false }) => Err("satellite DMA erase error"),
+                destination: 0,
+                succeeded: true,
+            }) => Ok(()),
+            Ok(Packet::DmaRemoveTraceReply {
+                destination: 0,
+                succeeded: false,
+            }) => Err("satellite DMA erase error"),
             Ok(_) => Err("adding trace failed, unexpected aux packet"),
             Err(_) => Err("erasing trace failed, aux error"),
         }
@@ -558,6 +613,7 @@ pub mod drtio {
             linkno,
             &Packet::DmaPlaybackRequest {
                 id: id,
+                source: 0,
                 destination: destination,
                 timestamp: timestamp,
             },
@@ -565,8 +621,14 @@ pub mod drtio {
         )
         .await;
         match reply {
-            Ok(Packet::DmaPlaybackReply { succeeded: true }) => Ok(()),
+            Ok(Packet::DmaPlaybackReply {
-            Ok(Packet::DmaPlaybackReply { succeeded: false }) => Err("error on DMA playback request"),
+                destination: 0,
+                succeeded: true,
+            }) => Ok(()),
+            Ok(Packet::DmaPlaybackReply {
+                destination: 0,
+                succeeded: false,
+            }) => Err("error on DMA playback request"),
             Ok(_) => Err("received unexpected aux packet during DMA playback"),
             Err(_) => Err("aux error on DMA playback"),
         }
@@ -689,6 +751,7 @@ pub mod drtio {
             linkno,
             &Packet::SubkernelLoadRunRequest {
                 id: id,
+                source: 0,
                 destination: destination,
                 run: run,
             },
@@ -696,8 +759,14 @@ pub mod drtio {
         )
         .await?;
         match reply {
-            Packet::SubkernelLoadRunReply { succeeded: true } => return Ok(()),
+            Packet::SubkernelLoadRunReply {
-            Packet::SubkernelLoadRunReply { succeeded: false } => return Err("error on subkernel run request"),
+                destination: 0,
+                succeeded: true,
+            } => return Ok(()),
+            Packet::SubkernelLoadRunReply {
+                destination: 0,
+                succeeded: false,
+            } => return Err("error on subkernel run request"),
             _ => return Err("received unexpected aux packet during subkernel run"),
         }
     }
@@ -747,6 +816,7 @@ pub mod drtio {
             timer,
             message,
             |slice, status, len| Packet::SubkernelMessage {
+                source: 0,
                 destination: destination,
                 id: id,
                 status: status,

src/runtime/src/subkernel.rs

@@ -13,7 +13,7 @@ use crate::rtio_mgt::drtio;
 pub enum FinishStatus {
     Ok,
     CommLost,
-    Exception,
+    Exception(u8), // exception source
 }
 
 #[derive(Debug, PartialEq, Clone, Copy)]
@@ -121,14 +121,14 @@ pub async fn clear_subkernels() {
     CURRENT_MESSAGES.async_lock().await.clear();
 }
 
-pub async fn subkernel_finished(id: u32, with_exception: bool) {
+pub async fn subkernel_finished(id: u32, with_exception: bool, exception_src: u8) {
     // called upon receiving DRTIO SubkernelRunDone
     // may be None if session ends and is cleared
     if let Some(subkernel) = SUBKERNELS.async_lock().await.get_mut(&id) {
         if subkernel.state == SubkernelState::Running {
             subkernel.state = SubkernelState::Finished {
                 status: match with_exception {
-                    true => FinishStatus::Exception,
+                    true => FinishStatus::Exception(exception_src),
                     false => FinishStatus::Ok,
                 },
             }
@@ -196,11 +196,8 @@ pub async fn await_finish(
                 Ok(SubkernelFinished {
                     id: id,
                     status: status,
-                    exception: if status == FinishStatus::Exception {
+                    exception: if let FinishStatus::Exception(dest) = status {
-                        Some(
+                        Some(drtio::subkernel_retrieve_exception(aux_mutex, routing_table, timer, dest).await?)
-                            drtio::subkernel_retrieve_exception(aux_mutex, routing_table, timer, subkernel.destination)
-                                .await?,
-                        )
                     } else {
                         None
                     },
@@ -292,7 +289,7 @@ pub async fn message_await(id: u32, timeout: u64, timer: GlobalTimer) -> Result<
                 status: FinishStatus::CommLost,
             } => return Err(Error::CommLost),
             SubkernelState::Finished {
-                status: FinishStatus::Exception,
+                status: FinishStatus::Exception(_),
             } => return Err(Error::SubkernelException),
             _ => (),
         }