Handle network media loss

pixie-uefi/src/os/executor/mod.rs

@@ -15,6 +15,7 @@ use futures::channel::oneshot;
 use spin::Mutex;
 use uefi::proto::console::text::Color;
 
+use crate::os;
 use crate::os::executor::event::{Event, EventTrigger};
 use crate::os::send_wrapper::SendWrapper;
 use crate::os::timer::Timer;
@@ -239,11 +240,7 @@ impl Executor {
             let task = EXECUTOR.lock().ready_tasks.pop_front();
             let Some(task) = task else {
                 // If we don't have anything ready, sleep until the next interrupt.
-                // SAFETY: hlt is available on all reasonable x86 processors and has no safety
-                // requirements.
-                unsafe {
-                    core::arch::asm!("hlt");
-                }
+                os::util::hlt();
                 do_wake(true);
                 continue;
             };

pixie-uefi/src/os/input.rs

@@ -3,6 +3,7 @@ use spin::Mutex;
 use uefi::boot::ScopedProtocol;
 use uefi::proto::console::text::{Input, Key};
 
+use crate::os;
 use crate::os::error::Result;
 use crate::os::executor::Executor;
 use crate::os::send_wrapper::SendWrapper;
@@ -21,3 +22,12 @@ pub async fn read_key() -> Result<Key> {
         Executor::wait_for_interrupt().await;
     }
 }
+
+pub fn wait_for_key() -> Result<()> {
+    loop {
+        os::util::hlt();
+        if INPUT.lock().read_key()?.is_some() {
+            return Ok(());
+        }
+    }
+}

pixie-uefi/src/os/mod.rs

@@ -22,6 +22,7 @@ pub mod net;
 mod send_wrapper;
 mod timer;
 pub mod ui;
+pub mod util;
 
 static INITIALIZED: AtomicBool = AtomicBool::new(false);
 

pixie-uefi/src/os/net/interface.rs

@@ -6,6 +6,8 @@ use uefi::Status;
 
 use super::ETH_PACKET_SIZE;
 use crate::os::send_wrapper::SendWrapper;
+use crate::os::{input, ui};
+use crate::power_control;
 
 type Snp = SendWrapper<ScopedProtocol<SimpleNetwork>>;
 
@@ -68,7 +70,19 @@ impl TxToken for SnpTxToken<'_> {
         snp.transmit(0, payload, None, None, None)
             .expect("Failed to transmit frame");
         // Wait until sending is complete.
-        while snp.get_recycled_transmit_buffer_status().unwrap().is_none() {}
+        while snp.get_recycled_transmit_buffer_status().unwrap().is_none() {
+            if snp.mode().media_present.0 == 0 {
+                let err = uefi::boot::set_watchdog_timer(0, 0x10000, None);
+                if let Err(err) = err {
+                    if err.status() != Status::UNSUPPORTED {
+                        log::error!("Error disabling watchdog: {err:?}");
+                    }
+                }
+                ui::red_screen();
+                input::wait_for_key().expect("Failed to wait for input");
+                power_control::reset();
+            }
+        }
         ret
     }
 }

pixie-uefi/src/os/ui.rs

@@ -307,3 +307,13 @@ pub fn update_content<F: Fn(&mut DrawArea)>(f: F) {
         .try_lock()
         .expect("content draw area is locked"));
 }
+
+pub fn red_screen() {
+    let mut s = SCREEN.lock();
+    s.back_buffer.fill(ScreenChar {
+        c: ' '.try_into().unwrap(),
+        fg: Color::Red,
+        bg: Color::Red,
+    });
+    s.flush();
+}

pixie-uefi/src/os/util.rs

@@ -0,0 +1,7 @@
+pub fn hlt() {
+    // SAFETY: hlt is available on all reasonable x86 processors and has no safety
+    // requirements.
+    unsafe {
+        core::arch::asm!("hlt");
+    }
+}