Merge pull request #19 from japaric/panic

[RFC] default panic! to abort, drop panic-* features, add panic_fmt! macro

Author: japaric

cortex-m-rt/Cargo.toml

@@ -7,7 +7,7 @@ keywords = ["arm", "cortex-m", "runtime", "startup"]
 license = "MIT OR Apache-2.0"
 name = "cortex-m-rt"
 repository = "https://github.com/japaric/cortex-m-rt"
-version = "0.2.4"
+version = "0.3.0"
 
 [dependencies]
 r0 = "0.2.1"
@@ -16,17 +16,11 @@ r0 = "0.2.1"
 optional = true
 version = "0.2.7"
 
-[dependencies.cortex-m-semihosting]
-optional = true
-version = "0.1.3"
-
 [features]
 default = ["exceptions", "linker-script"]
 # service all exceptions using the default handler
 exceptions = ["cortex-m"]
 # generic linker script
 linker-script = []
-# prints panic messages to the ITM
-panic-over-itm = ["cortex-m"]
-# prints panic messages to the host stdout
-panic-over-semihosting = ["cortex-m-semihosting"]
+# provides a panic_fmt implementation that calls the abort instruction (`udf 0xfe`)
+abort-on-panic = []

cortex-m-rt/src/lang_items.rs

@@ -1,37 +1,12 @@
 /// Default panic handler
+#[cfg(feature = "abort-on-panic")]
 #[lang = "panic_fmt"]
-#[linkage = "weak"]
 unsafe extern "C" fn panic_fmt(
-    _args: ::core::fmt::Arguments,
-    _file: &'static str,
-    _line: u32,
+    _: ::core::fmt::Arguments,
+    _: &'static str,
+    _: u32,
 ) -> ! {
-    match () {
-        #[cfg(feature = "panic-over-itm")]
-        () => {
-            use cortex_m::itm;
-            use cortex_m::peripheral::ITM;
-
-            let port = &(*ITM.get()).stim[0];
-            iprint!(port, "panicked at '");
-            itm::write_fmt(port, _args);
-            iprintln!(port, "', {}:{}", _file, _line);
-        }
-        #[cfg(feature = "panic-over-semihosting")]
-        () => {
-            hprint!("panicked at '");
-            ::cortex_m_semihosting::io::write_fmt(_args);
-            hprintln!("', {}:{}", _file, _line);
-        }
-        #[cfg(not(any(feature = "panic-over-itm",
-                      feature = "panic-over-semihosting")))]
-        () => {}
-    }
-
-    #[cfg(target_arch = "arm")]
-    asm!("bkpt" :::: "volatile");
-
-    loop {}
+    ::core::intrinsics::abort()
 }
 
 /// Lang item required to make the normal `main` work in applications

cortex-m-rt/src/lib.rs

@@ -145,6 +145,7 @@
 //!  8000404:       b084            sub     sp, #16
 //! ```
 
+#![cfg_attr(feature = "abort-on-panic", feature(core_intrinsics))]
 #![deny(missing_docs)]
 #![deny(warnings)]
 #![feature(asm)]
@@ -154,13 +155,9 @@
 #![feature(used)]
 #![no_std]
 
-#[cfg(any(feature = "panic-over-itm", feature = "exceptions"))]
-#[cfg_attr(feature = "panic-over-itm", macro_use)]
+#[cfg(feature = "exceptions")]
 extern crate cortex_m;
 extern crate compiler_builtins;
-#[cfg(feature = "panic-over-semihosting")]
-#[macro_use]
-extern crate cortex_m_semihosting;
 extern crate r0;
 
 mod lang_items;
@@ -189,8 +186,8 @@ extern "C" {
 /// This is the entry point of all programs
 #[link_section = ".reset_handler"]
 unsafe extern "C" fn reset_handler() -> ! {
-    ::r0::zero_bss(&mut _sbss, &mut _ebss);
-    ::r0::init_data(&mut _sdata, &mut _edata, &_sidata);
+    r0::zero_bss(&mut _sbss, &mut _ebss);
+    r0::init_data(&mut _sdata, &mut _edata, &_sidata);
 
     // Neither `argc` or `argv` make sense in bare metal context so we just
     // stub them