Update third_party/lang-items to support OpenSK.

third_party/lang-items/src/panic_handler.rs

@@ -1,72 +1,26 @@
-//! Lang item required to make the normal `main` work in applications
-//!
-//! This is how the `start` lang item works:
-//! When `rustc` compiles a binary crate, it creates a `main` function that looks
-//! like this:
-//!
-//! ```
-//! #[export_name = "main"]
-//! pub extern "C" fn rustc_main(argc: isize, argv: *const *const u8) -> isize {
-//!     start(main, argc, argv)
-//! }
-//! ```
-//!
-//! Where `start` is this function and `main` is the binary crate's `main`
-//! function.
-//!
-//! The final piece is that the entry point of our program, _start, has to call
-//! `rustc_main`. That's covered by the `_start` function in the root of this
-//! crate.
-
-use crate::led;
-use crate::timer;
-use crate::timer::Duration;
-use core::alloc::Layout;
+use crate::util;
+#[cfg(feature = "panic_console")]
+use core::fmt::Write;
 use core::panic::PanicInfo;
-
-#[lang = "start"]
-extern "C" fn start<T>(main: fn() -> T, _argc: isize, _argv: *const *const u8) -> i32
-where
-    T: Termination,
-{
-    main().report()
-}
-
-pub trait Termination {
-    fn report(self) -> i32;
-}
-
-impl Termination for () {
-    fn report(self) -> i32 {
-        0
-    }
-}
+#[cfg(feature = "panic_console")]
+use libtock_drivers::console::Console;
 
 #[panic_handler]
 fn panic_handler(_info: &PanicInfo) -> ! {
-    // Signal a panic using the LowLevelDebug capsule (if available).
-    super::debug::low_level_status_code(1);
+    util::signal_panic();
 
-    // Flash all LEDs (if available).
-    loop {
-        for led in led::all() {
-            led.on();
-        }
-        timer::sleep(Duration::from_ms(100));
-        for led in led::all() {
-            led.off();
-        }
-        timer::sleep(Duration::from_ms(100));
-    }
-}
-
-#[alloc_error_handler]
-fn cycle_leds(_: Layout) -> ! {
-    loop {
-        for led in led::all() {
-            led.on();
-            timer::sleep(Duration::from_ms(100));
-            led.off();
+    #[cfg(feature = "panic_console")]
+    {
+        let mut console = Console::new();
+        writeln!(console, "{}", _info).ok();
+        console.flush();
+        // Force the kernel to report the panic cause, by reading an invalid address.
+        // The memory protection unit should be setup by the Tock kernel to prevent apps from accessing
+        // address zero.
+        unsafe {
+            core::ptr::read_volatile(0 as *const usize);
         }
     }
+
+    util::flash_all_leds();
 }