process RPC replies (WIP)

src/runtime/src/comms.rs

@@ -2,6 +2,8 @@ use core::mem::transmute;
 use core::fmt;
 use core::cell::RefCell;
 use alloc::rc::Rc;
+use alloc::sync::Arc;
+use alloc::{vec, vec::Vec};
 use log::{debug, warn, error};
 
 use num_derive::{FromPrimitive, ToPrimitive};
@@ -17,12 +19,11 @@ use libboard_zynq::{
     },
     timer::GlobalTimer,
 };
-use libsupport_zynq::alloc::{vec, vec::Vec};
 use libasync::{smoltcp::{Sockets, TcpStream}, task};
-use alloc::sync::Arc;
 
 use crate::proto_async::*;
 use crate::kernel;
+use crate::rpc;
 use crate::moninj;
 
 
@@ -85,35 +86,93 @@ async fn write_header(stream: &TcpStream, reply: Reply) -> Result<()> {
     Ok(())
 }
 
-async fn handle_connection(stream: &TcpStream, control: Rc<RefCell<kernel::Control>>) -> Result<()> {
-    expect(&stream, b"ARTIQ coredev\n").await?;
-    debug!("received connection");
-    loop {
+async fn read_request(stream: &TcpStream, allow_close: bool) -> Result<Option<Request>> {
     match expect(&stream, &[0x5a, 0x5a, 0x5a, 0x5a]).await {
         Ok(true) => {}
         Ok(false) =>
             return Err(Error::UnexpectedPattern),
-            // Peer has closed the connection.
-            // Closing here is a normal condition so do not report an error.
-            // An error is still reported if the connection is unexpectedly closed elsewhere.
-            Err(smoltcp::Error::Illegal) =>
-                return Ok(()),
+        Err(smoltcp::Error::Illegal) => {
+            if allow_close {
+                debug!("peer closed connection");
+                return Ok(None);
+            } else {
+                error!("peer unexpectedly closed connection");
+                return Err(smoltcp::Error::Illegal)?;
+            }
+        },
         Err(e) =>
             return Err(e)?,
     }
-        let request: Request = FromPrimitive::from_i8(read_i8(&stream).await?)
-            .ok_or(Error::UnrecognizedPacket)?;
+    Ok(Some(FromPrimitive::from_i8(read_i8(&stream).await?).ok_or(Error::UnrecognizedPacket)?))
+}
+
+async fn handle_run_kernel(stream: &TcpStream, control: &mut kernel::Control) -> Result<()> {
+    control.tx.async_send(kernel::Message::StartRequest).await;
+    loop {
+        let reply = control.rx.async_recv().await;
+        match *reply {
+            kernel::Message::RpcSend { is_async, data } => {
+                write_header(&stream, Reply::RPCRequest).await?;
+                write_bool(&stream, is_async).await?;
+                stream.send(data.iter().copied()).await?;
+                if !is_async {
+                    let host_request = read_request(stream, false).await?.unwrap();
+                    match host_request {
+                        Request::RPCReply => {
+                            let tag = read_bytes(&stream, 512).await?;
+                            let rpc_recv_request = control.rx.async_recv().await;
+                            let slot = if let kernel::Message::RpcRecvRequest(slot) = *rpc_recv_request {
+                                slot
+                            } else {
+                                panic!(
+                                    "expected root value slot from core1, not {:?}", rpc_recv_request);
+                            };
+                            rpc::recv_return(stream, &tag, slot, &async move |size| -> *mut () {
+                                if size == 0 {
+                                    // Don't try to allocate zero-length values, as RpcRecvReply(0) is
+                                    // used to terminate the kernel-side receive loop.
+                                    return 0 as *mut ()
+                                }
+                                unimplemented!();
+                            }).await?;
+                            control.tx.async_send(kernel::Message::RpcRecvReply(Ok(0))).await;
+                        },
+                        Request::RPCException => unimplemented!(),
+                        _ => {
+                            error!("unexpected RPC request from host: {:?}", host_request);
+                            return Err(Error::UnrecognizedPacket)
+                        }
+                    }
+                }
+            },
+            kernel::Message::KernelFinished => {
+                write_header(&stream, Reply::KernelFinished).await?;
+                break;
+            },
+            _ => {
+                panic!("unexpected message from core1 while kernel was running: {:?}", reply);
+            }
+        }
+    }
+    Ok(())
+}
+
+async fn handle_connection(stream: &TcpStream, control: Rc<RefCell<kernel::Control>>) -> Result<()> {
+    expect(&stream, b"ARTIQ coredev\n").await?;
+    debug!("received connection");
+    loop {
+        let request = read_request(stream, true).await?;
+        if request.is_none() {
+            return Ok(());
+        }
+        let request = request.unwrap();
         match request {
             Request::SystemInfo => {
                 write_header(&stream, Reply::SystemInfo).await?;
                 stream.send("ARZQ".bytes()).await?;
             },
             Request::LoadKernel => {
-                let length = read_i32(&stream).await? as usize;
-                if length < 1024*1024 {
-                    let mut buffer = vec![0; length];
-                    read_chunk(&stream, &mut buffer).await?;
-
+                let buffer = read_bytes(&stream, 1024*1024).await?;
                 let mut control = control.borrow_mut();
                 control.restart();
                 control.tx.async_send(kernel::Message::LoadRequest(Arc::new(buffer))).await;
@@ -125,42 +184,22 @@ async fn handle_connection(stream: &TcpStream, control: Rc<RefCell<kernel::Contr
                         write_chunk(&stream, b"core1 failed to process data").await?;
                     },
                     _ => {
-                            error!("received unexpected message from core1: {:?}", reply);
+                        error!("unexpected message from core1: {:?}", reply);
                         write_header(&stream, Reply::LoadFailed).await?;
                         write_chunk(&stream, b"core1 sent unexpected reply").await?;
                     }
                 }
-                } else {
-                    read_drain(&stream, length).await?;
-                    write_header(&stream, Reply::LoadFailed).await?;
-                    write_chunk(&stream, b"kernel is too large").await?;
-                }
             },
             Request::RunKernel => {
-                let mut control = control.borrow_mut();
-                control.tx.async_send(kernel::Message::StartRequest).await;
-                loop {
-                    let reply = control.rx.async_recv().await;
-                    match *reply {
-                        kernel::Message::KernelFinished => {
-                            write_header(&stream, Reply::KernelFinished).await?;
-                            break;
-                        },
-                        kernel::Message::RpcSend { is_async, data } => {
-                            write_header(&stream, Reply::RPCRequest).await?;
-                            write_bool(&stream, is_async).await?;
-                            stream.send(data.iter().copied()).await?;
+                handle_run_kernel(stream, &mut control.borrow_mut()).await?;
             },
             _ => {
-                            error!("received unexpected message from core1 while kernel was running: {:?}", reply);
+                error!("unexpected request from host: {:?}", request);
+                return Err(Error::UnrecognizedPacket)
             }
         }
     }
 }
-            _ => return Err(Error::UnrecognizedPacket)
-        }
-    }
-}
 
 
 const HWADDR: [u8; 6] = [0, 0x23, 0xab, 0xad, 0x1d, 0xea];

src/runtime/src/kernel.rs

@@ -19,6 +19,8 @@ pub enum Message {
     StartRequest,
     KernelFinished,
     RpcSend { is_async: bool, data: Arc<Vec<u8>> },
+    RpcRecvRequest(*mut ()),
+    RpcRecvReply(Result<usize, ()>),
 }
 
 static CHANNEL_0TO1: Mutex<Option<sync_channel::Receiver<Message>>> = Mutex::new(None);
@@ -64,23 +66,31 @@ impl Control {
 static mut KERNEL_CHANNEL_0TO1: *mut () = ptr::null_mut();
 static mut KERNEL_CHANNEL_1TO0: *mut () = ptr::null_mut();
 
-extern fn rpc_send(service: u32, tag: &CSlice<u8>, data: *const *const ()) {
-    let core1_rx: &mut sync_channel::Receiver<Message> = unsafe { mem::transmute(KERNEL_CHANNEL_0TO1) };
+fn rpc_send_common(is_async: bool, service: u32, tag: &CSlice<u8>, data: *const *const ()) {
     let core1_tx: &mut sync_channel::Sender<Message> = unsafe { mem::transmute(KERNEL_CHANNEL_1TO0) };
     let mut buffer = Vec::<u8>::new();
     rpc::send_args(&mut buffer, service, tag.as_ref(), data).expect("RPC encoding failed");
-    core1_tx.send(Message::RpcSend { is_async: false, data: Arc::new(buffer) })
+    core1_tx.send(Message::RpcSend { is_async: is_async, data: Arc::new(buffer) });
+}
+
+extern fn rpc_send(service: u32, tag: &CSlice<u8>, data: *const *const ()) {
+    rpc_send_common(false, service, tag, data);
 }
 
 extern fn rpc_send_async(service: u32, tag: &CSlice<u8>, data: *const *const ()) {
-    let core1_tx: &mut sync_channel::Sender<Message> = unsafe { mem::transmute(KERNEL_CHANNEL_1TO0) };
-    let mut buffer = Vec::<u8>::new();
-    rpc::send_args(&mut buffer, service, tag.as_ref(), data).expect("RPC encoding failed");
-    core1_tx.send(Message::RpcSend { is_async: true, data: Arc::new(buffer) })
+    rpc_send_common(true, service, tag, data);
 }
 
 extern fn rpc_recv(slot: *mut ()) -> usize {
-    unimplemented!();
+    let core1_rx: &mut sync_channel::Receiver<Message> = unsafe { mem::transmute(KERNEL_CHANNEL_0TO1) };
+    let core1_tx: &mut sync_channel::Sender<Message> = unsafe { mem::transmute(KERNEL_CHANNEL_1TO0) };
+    core1_tx.send(Message::RpcRecvRequest(slot));
+    let reply = core1_rx.recv();
+    match *reply {
+        Message::RpcRecvReply(Ok(alloc_size)) => alloc_size,
+        Message::RpcRecvReply(Err(_)) => unimplemented!(),
+        _ => panic!("received unexpected reply to RpcRecvRequest: {:?}", reply)
+    }
 }
 
 macro_rules! api {

src/runtime/src/main.rs

@@ -2,6 +2,7 @@
 #![no_main]
 #![recursion_limit="1024"]  // for futures_util::select!
 #![feature(llvm_asm)]
+#![feature(async_closure)]
 
 extern crate alloc;
 

src/runtime/src/proto_async.rs

@@ -1,6 +1,7 @@
 use core::task::Poll;
 use core::cmp::min;
 use core::cell::RefCell;
+use alloc::{vec, vec::Vec};
 
 use libboard_zynq::smoltcp;
 use libasync::smoltcp::TcpStream;
@@ -86,16 +87,14 @@ pub async fn read_chunk(stream: &TcpStream, destination: &mut [u8]) -> Result<()
     Ok(())
 }
 
-pub async fn read_drain(stream: &TcpStream, total: usize) -> Result<()> {
-    let mut done = 0;
-    while done < total {
-        let count = stream.recv(|buf| {
-            let count = min(total - done, buf.len());
-            Poll::Ready((count, count))
-        }).await?;
-        done += count;
+pub async fn read_bytes(stream: &TcpStream, max_length: usize) -> Result<Vec<u8>> {
+    let length = read_i32(&stream).await? as usize;
+    if length > max_length {
+        return Err(smoltcp::Error::Exhausted);
     }
-    Ok(())
+    let mut buffer = vec![0; length];
+    read_chunk(&stream, &mut buffer).await?;
+    Ok(buffer)
 }
 
 pub async fn write_i8(stream: &TcpStream, value: i8) -> Result<()> {