From f156c7c6d1e7832eb75f9e80b1922f7e064f8b0d Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Sun, 6 Aug 2017 19:52:11 +0800
Subject: [PATCH] print panic messages on UART

---
 firmware/Cargo.toml  | 2 +-
 firmware/src/main.rs | 9 ++++++++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/firmware/Cargo.toml b/firmware/Cargo.toml
index ec00b96..2ef1c05 100644
--- a/firmware/Cargo.toml
+++ b/firmware/Cargo.toml
@@ -5,7 +5,7 @@ authors = ["whitequark <whitequark@whitequark.org>"]
 
 [dependencies]
 cortex-m = "0.3.1"
-cortex-m-rt = { version = "0.3.5", features = ["abort-on-panic"] }
+cortex-m-rt = { version = "0.3.5" }
 
 [dependencies.tm4c129x]
 git = "https://github.com/m-labs/dslite2svd"
diff --git a/firmware/src/main.rs b/firmware/src/main.rs
index ba0883a..05e9864 100644
--- a/firmware/src/main.rs
+++ b/firmware/src/main.rs
@@ -1,4 +1,4 @@
-#![feature(used, const_fn, core_float, asm)]
+#![feature(used, const_fn, core_float, asm, lang_items)]
 #![no_std]
 
 extern crate cortex_m;
@@ -30,6 +30,13 @@ macro_rules! println {
     ($fmt:expr, $($arg:tt)*) => (print!(concat!($fmt, "\n"), $($arg)*));
 }
 
+#[no_mangle]
+#[lang = "panic_fmt"]
+fn panic_fmt(args: core::fmt::Arguments, file: &'static str, line: u32) -> ! {
+    println!("panic at {}:{}: {}", file, line, args);
+    loop {}
+}
+
 #[macro_use]
 mod board;
 mod ethmac;