src/libksupport/src/kernel/mod.rs

@@ -103,6 +103,7 @@ pub enum Message {
     SubkernelMsgRecvRequest {
         id: u32,
         timeout: u64,
+        tags: Vec<u8>,
     },
     #[cfg(has_drtio)]
     SubkernelMsgRecvReply {

src/libksupport/src/kernel/rpc.rs

@@ -10,7 +10,7 @@ use crate::{eh_artiq, rpc::send_args};
 fn rpc_send_common(is_async: bool, service: u32, tag: &CSlice<u8>, data: *const *const ()) {
     let core1_tx = unsafe { KERNEL_CHANNEL_1TO0.as_mut().unwrap() };
     let mut buffer = Vec::<u8>::new();
-    send_args(&mut buffer, service, tag.as_ref(), data).expect("RPC encoding failed");
+    send_args(&mut buffer, service, tag.as_ref(), data, true).expect("RPC encoding failed");
     core1_tx.send(Message::RpcSend { is_async, data: buffer });
 }
 

src/libksupport/src/kernel/subkernel.rs

@@ -53,7 +53,7 @@ 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 ()) {
     let mut buffer = Vec::<u8>::new();
-    send_args(&mut buffer, 0, tag.as_ref(), data).expect("RPC encoding failed");
+    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
     buffer[3] = count;
     unsafe {
@@ -68,7 +68,7 @@ pub extern "C" fn send_message(id: u32, count: u8, tag: &CSlice<u8>, data: *cons
     }
 }
 
-pub extern "C" fn await_message(id: u32, timeout: u64, min: u8, max: u8) {
+pub extern "C" fn await_message(id: u32, timeout: u64, tags: &CSlice<u8>, min: u8, max: u8) {
     unsafe {
         KERNEL_CHANNEL_1TO0
             .as_mut()
@@ -76,6 +76,7 @@ pub extern "C" fn await_message(id: u32, timeout: u64, min: u8, max: u8) {
             .send(Message::SubkernelMsgRecvRequest {
                 id: id,
                 timeout: timeout,
+                tags: tags.as_ref().to_vec(),
             });
     }
     match unsafe { KERNEL_CHANNEL_0TO1.as_mut().unwrap() }.recv() {

src/libksupport/src/rpc.rs

@@ -175,7 +175,12 @@ where
     }
 }
 
-pub fn recv_return<F, R>(reader: &mut R, tag_bytes: &[u8], data: *mut (), alloc: &mut F) -> Result<(), Error>
+pub fn recv_return<'a, F, R>(
+    reader: &mut R,
+    tag_bytes: &'a [u8],
+    data: *mut (),
+    alloc: &mut F,
+) -> Result<&'a [u8], Error>
 where
     F: FnMut(usize) -> *mut (),
     R: Read + ?Sized,
@@ -187,12 +192,22 @@ where
     let mut data = data;
     unsafe { recv_value(reader, tag, &mut data, alloc)? };
 
-    Ok(())
+    Ok(it.data)
 }
 
-unsafe fn send_elements<W>(writer: &mut W, elt_tag: Tag, length: usize, data: *const ()) -> Result<(), Error>
-where W: Write + ?Sized {
+unsafe fn send_elements<W>(
+    writer: &mut W,
+    elt_tag: Tag,
+    length: usize,
+    data: *const (),
+    write_tags: bool,
+) -> Result<(), Error>
+where
+    W: Write + ?Sized,
+{
+    if write_tags {
         writer.write_u8(elt_tag.as_u8())?;
+    }
     match elt_tag {
         // we cannot use NativeEndian::from_slice_i32 as the data is not mutable,
         // and that is not needed as the data is already in native endian
@@ -211,14 +226,14 @@ where W: Write + ?Sized {
         _ => {
             let mut data = data;
             for _ in 0..length {
-                send_value(writer, elt_tag, &mut data)?;
+                send_value(writer, elt_tag, &mut data, write_tags)?;
             }
         }
     }
     Ok(())
 }
 
-unsafe fn send_value<W>(writer: &mut W, tag: Tag, data: &mut *const ()) -> Result<(), Error>
+unsafe fn send_value<W>(writer: &mut W, tag: Tag, data: &mut *const (), write_tags: bool) -> Result<(), Error>
 where W: Write + ?Sized {
     macro_rules! consume_value {
         ($ty:ty, | $ptr:ident | $map:expr) => {{
@@ -228,7 +243,9 @@ where W: Write + ?Sized {
         }};
     }
 
+    if write_tags {
         writer.write_u8(tag.as_u8())?;
+    }
     match tag {
         Tag::None => Ok(()),
         Tag::Bool => consume_value!(u8, |ptr| writer.write_u8(*ptr)),
@@ -240,12 +257,14 @@ where W: Write + ?Sized {
         Tag::Bytes | Tag::ByteArray => consume_value!(CSlice<u8>, |ptr| writer.write_bytes((*ptr).as_ref())),
         Tag::Tuple(it, arity) => {
             let mut it = it.clone();
+            if write_tags {
                 writer.write_u8(arity)?;
+            }
             let mut max_alignment = 0;
             for _ in 0..arity {
                 let tag = it.next().expect("truncated tag");
                 max_alignment = core::cmp::max(max_alignment, tag.alignment());
-                send_value(writer, tag, data)?
+                send_value(writer, tag, data, write_tags)?
             }
             *data = round_up_const(*data, max_alignment);
             Ok(())
@@ -260,11 +279,13 @@ where W: Write + ?Sized {
                 let length = (**ptr).length as usize;
                 writer.write_u32((*ptr).length)?;
                 let tag = it.clone().next().expect("truncated tag");
-                send_elements(writer, tag, length, (**ptr).elements)
+                send_elements(writer, tag, length, (**ptr).elements, write_tags)
             })
         }
         Tag::Array(it, num_dims) => {
+            if write_tags {
                 writer.write_u8(num_dims)?;
+            }
             consume_value!(*const (), |buffer| {
                 let elt_tag = it.clone().next().expect("truncated tag");
 
@@ -276,14 +297,14 @@ where W: Write + ?Sized {
                     })
                 }
                 let length = total_len as usize;
-                send_elements(writer, elt_tag, length, *buffer)
+                send_elements(writer, elt_tag, length, *buffer, write_tags)
             })
         }
         Tag::Range(it) => {
             let tag = it.clone().next().expect("truncated tag");
-            send_value(writer, tag, data)?;
-            send_value(writer, tag, data)?;
-            send_value(writer, tag, data)?;
+            send_value(writer, tag, data, write_tags)?;
+            send_value(writer, tag, data, write_tags)?;
+            send_value(writer, tag, data, write_tags)?;
             Ok(())
         }
         Tag::Keyword(it) => {
@@ -295,7 +316,7 @@ where W: Write + ?Sized {
                 writer.write_string(str::from_utf8((*ptr).name.as_ref()).unwrap())?;
                 let tag = it.clone().next().expect("truncated tag");
                 let mut data = ptr.offset(1) as *const ();
-                send_value(writer, tag, &mut data)
+                send_value(writer, tag, &mut data, write_tags)
             })
             // Tag::Keyword never appears in composite types, so we don't have
             // to accurately advance data.
@@ -310,8 +331,16 @@ where W: Write + ?Sized {
     }
 }
 
-pub fn send_args<W>(writer: &mut W, service: u32, tag_bytes: &[u8], data: *const *const ()) -> Result<(), Error>
-where W: Write + ?Sized {
+pub fn send_args<W>(
+    writer: &mut W,
+    service: u32,
+    tag_bytes: &[u8],
+    data: *const *const (),
+    write_tags: bool,
+) -> Result<(), Error>
+where
+    W: Write + ?Sized,
+{
     let (arg_tags_bytes, return_tag_bytes) = split_tag(tag_bytes);
 
     let mut args_it = TagIterator::new(arg_tags_bytes);
@@ -322,7 +351,7 @@ where W: Write + ?Sized {
     for index in 0.. {
         if let Some(arg_tag) = args_it.next() {
             let mut data = unsafe { *data.offset(index) };
-            unsafe { send_value(writer, arg_tag, &mut data)? };
+            unsafe { send_value(writer, arg_tag, &mut data, write_tags)? };
         } else {
             break;
         }
@@ -450,7 +479,7 @@ pub mod tag {
 
     #[derive(Debug, Clone, Copy)]
     pub struct TagIterator<'a> {
-        data: &'a [u8],
+        pub data: &'a [u8],
     }
 
     impl<'a> TagIterator<'a> {

src/runtime/src/comms.rs

@@ -5,7 +5,7 @@ use core_io::Error as IoError;
 use cslice::CSlice;
 use futures::{future::FutureExt, select_biased};
 #[cfg(has_drtio)]
-use io::{Cursor, ProtoRead};
+use io::Cursor;
 #[cfg(has_drtio)]
 use ksupport::rpc;
 use ksupport::{kernel, resolve_channel_name};
@@ -451,7 +451,7 @@ async fn handle_run_kernel(
                     .await;
             }
             #[cfg(has_drtio)]
-            kernel::Message::SubkernelMsgRecvRequest { id, timeout } => {
+            kernel::Message::SubkernelMsgRecvRequest { id, timeout, tags } => {
                 let message_received = subkernel::message_await(id, timeout, timer).await;
                 let (status, count) = match message_received {
                     Ok(ref message) => (kernel::SubkernelStatus::NoError, message.count),
@@ -471,7 +471,7 @@ async fn handle_run_kernel(
                 if let Ok(message) = message_received {
                     // receive code almost identical to RPC recv, except we are not reading from a stream
                     let mut reader = Cursor::new(message.data);
-                    let mut tag: [u8; 1] = [message.tag];
+                    let mut current_tags: &[u8] = &tags;
                     let mut i = 0;
                     loop {
                         // kernel has to consume all arguments in the whole message
@@ -479,7 +479,7 @@ async fn handle_run_kernel(
                             kernel::Message::RpcRecvRequest(slot) => slot,
                             other => panic!("expected root value slot from core1, not {:?}", other),
                         };
-                        rpc::recv_return(&mut reader, &tag, slot, &mut |size| {
+                        let remaining_tags = rpc::recv_return(&mut reader, &current_tags, slot, &mut |size| {
                             if size == 0 {
                                 0 as *mut ()
                             } else {
@@ -500,7 +500,7 @@ async fn handle_run_kernel(
                             .await;
                         i += 1;
                         if i < count {
-                            tag[0] = reader.read_u8()?;
+                            current_tags = remaining_tags;
                         } else {
                             break;
                         }

src/runtime/src/main.rs

@@ -62,6 +62,7 @@ mod grabber {
     use libasync::delay;
     use libboard_artiq::grabber;
     use libboard_zynq::time::Milliseconds;
+
     use crate::GlobalTimer;
     pub async fn grabber_thread(timer: GlobalTimer) {
         let mut countdown = timer.countdown();

src/runtime/src/subkernel.rs

@@ -212,7 +212,6 @@ pub async fn await_finish(
 pub struct Message {
     from_id: u32,
     pub count: u8,
-    pub tag: u8,
     pub data: Vec<u8>,
 }
 
@@ -236,8 +235,7 @@ pub async fn message_handle_incoming(id: u32, last: bool, length: usize, data: &
                 Message {
                     from_id: id,
                     count: data[0],
-                    tag: data[1],
-                    data: data[2..length].to_vec(),
+                    data: data[1..length].to_vec(),
                 },
             );
         }

src/satman/src/subkernel.rs

@@ -6,7 +6,7 @@ use core::{cmp::min, option::NoneError, slice, str};
 
 use core_io::{Error as IoError, Write};
 use cslice::AsCSlice;
-use io::{Cursor, ProtoRead, ProtoWrite};
+use io::{Cursor, ProtoWrite};
 use ksupport::{eh_artiq, kernel, rpc};
 use libboard_artiq::{drtioaux_proto::{MASTER_PAYLOAD_MAX_SIZE, SAT_PAYLOAD_MAX_SIZE},
                      pl::csr};
@@ -14,12 +14,12 @@ use libboard_zynq::{time::Milliseconds, timer::GlobalTimer};
 use libcortex_a9::sync_channel::Receiver;
 use log::warn;
 
-#[derive(Debug, Clone, Copy, PartialEq)]
+#[derive(Debug, Clone, PartialEq)]
 enum KernelState {
     Absent,
     Loaded,
     Running,
-    MsgAwait(Milliseconds),
+    MsgAwait(Milliseconds, Vec<u8>),
     MsgSending,
 }
 
@@ -66,7 +66,6 @@ pub struct Sliceable {
 /* represents interkernel messages */
 struct Message {
     count: u8,
-    tag: u8,
     data: Vec<u8>,
 }
 
@@ -183,8 +182,7 @@ impl MessageManager {
             None => {
                 self.in_buffer = Some(Message {
                     count: data[0],
-                    tag: data[1],
-                    data: data[2..length].to_vec(),
+                    data: data[1..length].to_vec(),
                 });
             }
         };
@@ -509,9 +507,9 @@ impl<'a> Manager<'_> {
                 self.session.messages.accept_outgoing(data)?;
                 self.session.kernel_state = KernelState::MsgSending;
             }
-            kernel::Message::SubkernelMsgRecvRequest { id: _, timeout } => {
+            kernel::Message::SubkernelMsgRecvRequest { id: _, timeout, tags } => {
                 let max_time = timer.get_time() + Milliseconds(timeout);
-                self.session.kernel_state = KernelState::MsgAwait(max_time);
+                self.session.kernel_state = KernelState::MsgAwait(max_time, tags);
             }
             kernel::Message::UpDestinationsRequest(destination) => {
                 self.control
@@ -526,9 +524,9 @@ impl<'a> Manager<'_> {
     }
 
     fn process_external_messages(&mut self, timer: GlobalTimer) -> Result<(), Error> {
-        match self.session.kernel_state {
-            KernelState::MsgAwait(timeout) => {
-                if timer.get_time() > timeout {
+        match &self.session.kernel_state {
+            KernelState::MsgAwait(timeout, tags) => {
+                if timer.get_time() > *timeout {
                     self.control.tx.send(kernel::Message::SubkernelMsgRecvReply {
                         status: kernel::SubkernelStatus::Timeout,
                         count: 0,
@@ -541,8 +539,9 @@ impl<'a> Manager<'_> {
                         status: kernel::SubkernelStatus::NoError,
                         count: message.count,
                     });
+                    let tags = tags.clone();
                     self.session.kernel_state = KernelState::Running;
-                    self.pass_message_to_kernel(&message, timer)
+                    self.pass_message_to_kernel(&message, tags, timer)
                 } else {
                     Err(Error::AwaitingMessage)
                 }
@@ -560,9 +559,9 @@ impl<'a> Manager<'_> {
         }
     }
 
-    fn pass_message_to_kernel(&mut self, message: &Message, timer: GlobalTimer) -> Result<(), Error> {
+    fn pass_message_to_kernel(&mut self, message: &Message, tags: Vec<u8>, timer: GlobalTimer) -> Result<(), Error> {
         let mut reader = Cursor::new(&message.data);
-        let mut tag: [u8; 1] = [message.tag];
+        let mut current_tags: &[u8] = &tags;
         let mut i = message.count;
         loop {
             let slot = match recv_w_timeout(&mut self.control.rx, timer, 100)? {
@@ -571,7 +570,7 @@ impl<'a> Manager<'_> {
             };
             let mut exception: Option<Sliceable> = None;
             let mut unexpected: Option<String> = None;
-            rpc::recv_return(&mut reader, &tag, slot, &mut |size| {
+            let remaining_tags = rpc::recv_return(&mut reader, current_tags, slot, &mut |size| {
                 if size == 0 {
                     0 as *mut ()
                 } else {
@@ -610,8 +609,7 @@ impl<'a> Manager<'_> {
             if i == 0 {
                 break;
             } else {
-                // update the tag for next read
-                tag[0] = reader.read_u8()?;
+                current_tags = remaining_tags;
             }
         }
         Ok(())