feat(core/rust): introduce dbg_print and improve errors printing

[no changelog]

core/embed/rust/src/debug.rs

@@ -0,0 +1,33 @@
+use ufmt;
+
+#[cfg(feature = "micropython")]
+use crate::micropython;
+
+pub struct DebugConsole;
+
+impl ufmt::uWrite for DebugConsole {
+    type Error = core::convert::Infallible;
+
+    fn write_str(&mut self, s: &str) -> Result<(), Self::Error> {
+        #[cfg(feature = "micropython")]
+        micropython::print::print(s);
+
+        // TODO: add alternative if micropython is not available
+
+        Ok(())
+    }
+}
+
+#[macro_export]
+macro_rules! dbg_println {
+    ($($args:tt)*) => {
+        ufmt::uwriteln!($crate::debug::DebugConsole, $($args)*).ok();
+    };
+}
+
+#[macro_export]
+macro_rules! dbg_print {
+    ($($args:tt)*) => {
+        ufmt::uwrite!($crate::debug::DebugConsole, $($args)*).ok();
+    };
+}

core/embed/rust/src/lib.rs

@@ -39,6 +39,10 @@ pub mod translations;
 pub mod ui;
 pub mod strutil;
 
+#[cfg(feature = "debug")]
+#[macro_use]
+pub mod debug;
+
 #[cfg(feature = "debug")]
 #[cfg(not(test))]
 #[panic_handler]
@@ -48,13 +52,8 @@ pub mod strutil;
 fn panic_debug(panic_info: &core::panic::PanicInfo) -> ! {
     // Filling at least the file and line information, if available.
     // TODO: find out how to display message from panic_info.message()
-
     if let Some(location) = panic_info.location() {
-        let file = location.file();
+        trezorhal::fatal_error::__fatal_error("", "rs", location.file(), location.line(), "");
-        print!(file);
-        print!(":");
-        println!(inttostr!(location.line()));
-        trezorhal::fatal_error::__fatal_error("", "rs", file, location.line(), "");
     } else {
         trezorhal::fatal_error::__fatal_error("", "rs", "", 0, "");
     }

core/embed/rust/src/trezorhal/fatal_error.rs

@@ -10,6 +10,9 @@ use crate::ui::{
     ui_features::{ModelUI, UIFeaturesCommon},
 };
 
+#[cfg(feature = "debug")]
+use crate::dbg_println;
+
 fn shutdown() -> ! {
     unsafe { ffi::trezor_shutdown() }
 }
@@ -32,6 +35,23 @@ pub fn error_shutdown(title: &str, msg: &str, footer: &str) -> ! {
 /// In debug mode, also prints the error message to the console.
 #[inline(never)] // saves few kilobytes of flash
 pub fn __fatal_error(_expr: &str, msg: &str, _file: &str, _line: u32, _func: &str) -> ! {
+    #[cfg(feature = "debug")]
+    {
+        dbg_println!("=== FATAL ERROR");
+
+        if _line != 0 {
+            dbg_println!("Location: {}:{}", _file, _line);
+        }
+        if !_expr.is_empty() {
+            dbg_println!("Expression: {}", _expr);
+        }
+        if !msg.is_empty() {
+            dbg_println!("Message: {}", msg);
+        }
+
+        dbg_println!("===");
+    }
+
     error_shutdown("INTERNAL_ERROR", msg, "PLEASE VISIT\nTREZOR.IO/RSOD");
 }
 

core/embed/rust/src/ui/shape/display/bumps.rs

@@ -66,15 +66,15 @@ where
     };
 }
 
-// This function enables nested invocations of `run_with_bumps()`,
+/// This function enables nested invocations of `run_with_bumps()`,
-// which is necessary when the application needs to display a
+/// which is necessary when the application needs to display a
-// fatal error message and subsequently terminate.
+/// fatal error message and subsequently terminate.
-//
+///
-// SAFETY:
+/// # Safety
-// This function must be invoked exclusively in failure scenarios
+/// This function must be invoked exclusively in failure scenarios
-// where the application is required to display a fatal error
+/// where the application is required to display a fatal error
-// message and then shut down. It is safe to call this function
+/// message and then shut down. It is safe to call this function
-// only under these specific conditions.
+/// only under these specific conditions.
 pub unsafe fn unlock_bumps_on_failure() {
     // The application is single-threaded, so we can safely use a
     // static variable as a lock against nested calls.