Merge #56

56: Exception handler may return r=Disasm a=laanwj

We need exceptions to be able to return. For example, after fixing the issue that caused them in the first place (e.g. paging), or after emulating missing instructions and possibly updating `mepc`.

Co-authored-by: Wladimir J. van der Laan <laanwj@protonmail.com>

Author: bors[bot]

riscv-rt/src/lib.rs

@@ -416,7 +416,7 @@ pub struct TrapFrame {
 #[export_name = "_start_trap_rust"]
 pub extern "C" fn start_trap_rust(trap_frame: *const TrapFrame) {
     extern "C" {
-        fn ExceptionHandler(trap_frame: &TrapFrame) -> !;
+        fn ExceptionHandler(trap_frame: &TrapFrame);
         fn DefaultHandler();
     }