drop linker-flavor, port more examples

examples/hello.rs

@@ -2,17 +2,19 @@
 //!
 //! ---
 
-#![feature(asm)]
 #![no_main]
 #![no_std]
 
+extern crate cortex_m;
 #[macro_use]
-extern crate cortex_m_rt;
+extern crate cortex_m_rt as rt;
 extern crate cortex_m_semihosting as sh;
 extern crate panic_abort; // panicking behavior
 
 use core::fmt::Write;
 
+use cortex_m::asm;
+use rt::ExceptionFrame;
 use sh::hio;
 
 main!(main);
@@ -26,7 +28,17 @@ fn main() -> ! {
 
 exception!(DefaultHandler, dh);
 
-fn dh(_nr: u8) -> ! {
+#[inline(always)]
+fn dh(_nr: u8) {
+    asm::bkpt();
+}
+
+exception!(HardFault, hf);
+
+#[inline(always)]
+fn hf(_ef: &ExceptionFrame) -> ! {
+    asm::bkpt();
+
     loop {}
 }