Clean up emergency console and use panic for unexpected exceptions.
This removes `eprintln`, which was easy to misuse and not really sound.
Instead, use `emergency_uart`, which has been made unsafe with a clearly
documented safety requirement that it can only be called when the normal
UART instance will never be used again, e.g. just before rebooting.
Also changed `emergency_uart` to return an error rather than panicking,
so panic handler can ignore the error.
Test: atest vmbase_example.integration_test
Change-Id: I76ac1911cf905fde0010054cfd8bc239699298f6
diff --git a/libs/libvmbase/src/logger.rs b/libs/libvmbase/src/logger.rs
index 9130918..0059d11 100644
--- a/libs/libvmbase/src/logger.rs
+++ b/libs/libvmbase/src/logger.rs
@@ -16,7 +16,7 @@
//!
//! Internally uses the println! vmbase macro, which prints to crosvm's UART.
//! Note: may not work if the VM is in an inconsistent state. Exception handlers
-//! should avoid using this logger and instead print with eprintln!.
+//! should avoid using this logger.
use crate::console::println;
use core::sync::atomic::{AtomicBool, Ordering};