riscv-rt: use pac_enum macro for exception handling

riscv-rt/CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
-## v0.19.0 - Unreleased
+## v0.18.0 - Unreleased
 
 ### Added
 
@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Changed
 
+- Use `riscv::pac_enum` macro for exceptions
 - Deprecate `no-interrupts` feature in favor of `custom-interrupts`
 - Deprecate `no-exceptions` feature in favor of `custom-exceptions`
 - `_setup_interrupts` can now optionally receive an `usize` input argument
@@ -26,7 +27,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - We no longer re-export the `pre_init` macro. Use `core::arch::global_asm` instead.
 
-## v0.18.0 - 2026-01-13
+## v0.17.1 - 2026-01-13
 
 ### Fixed
 

riscv-rt/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "riscv-rt"
-version = "0.19.0"
+version = "0.18.0"
 rust-version = "1.81"
 repository = "https://github.com/rust-embedded/riscv"
 authors = ["The RISC-V Team <risc-v@teams.rust-embedded.org>"]

riscv-rt/src/exceptions.rs

@@ -11,59 +11,23 @@
 //! code to adapt for the target needs. In this case, you may need to opt out this module.
 //! To do so, activate the `custom-exceptions` feature of the `riscv-rt` crate.
 
-use crate::TrapFrame;
-
-extern "C" {
-    fn InstructionMisaligned(trap_frame: &TrapFrame);
-    fn InstructionFault(trap_frame: &TrapFrame);
-    fn IllegalInstruction(trap_frame: &TrapFrame);
-    fn Breakpoint(trap_frame: &TrapFrame);
-    fn LoadMisaligned(trap_frame: &TrapFrame);
-    fn LoadFault(trap_frame: &TrapFrame);
-    fn StoreMisaligned(trap_frame: &TrapFrame);
-    fn StoreFault(trap_frame: &TrapFrame);
-    fn UserEnvCall(trap_frame: &TrapFrame);
-    fn SupervisorEnvCall(trap_frame: &TrapFrame);
-    fn MachineEnvCall(trap_frame: &TrapFrame);
-    fn InstructionPageFault(trap_frame: &TrapFrame);
-    fn LoadPageFault(trap_frame: &TrapFrame);
-    fn StorePageFault(trap_frame: &TrapFrame);
-}
-
-/// Array with all the exception handlers sorted according to their exception source code.
-#[no_mangle]
-pub static __EXCEPTIONS: [Option<unsafe extern "C" fn(&TrapFrame)>; 16] = [
-    Some(InstructionMisaligned),
-    Some(InstructionFault),
-    Some(IllegalInstruction),
-    Some(Breakpoint),
-    Some(LoadMisaligned),
-    Some(LoadFault),
-    Some(StoreMisaligned),
-    Some(StoreFault),
-    Some(UserEnvCall),
-    Some(SupervisorEnvCall),
-    None,
-    Some(MachineEnvCall),
-    Some(InstructionPageFault),
-    Some(LoadPageFault),
-    None,
-    Some(StorePageFault),
-];
-
-/// It calls the corresponding exception handler depending on the exception source code.
-///
-/// # Safety
-///
-/// This function must be called only from the [`crate::start_trap_rust`] function.
-/// Do **NOT** call this function directly.
-#[no_mangle]
-pub unsafe extern "C" fn _dispatch_exception(trap_frame: &TrapFrame, code: usize) {
-    extern "C" {
-        fn ExceptionHandler(trap_frame: &TrapFrame);
-    }
-    match __EXCEPTIONS.get(code) {
-        Some(Some(handler)) => handler(trap_frame),
-        _ => ExceptionHandler(trap_frame),
-    }
+#[riscv::pac_enum(unsafe ExceptionNumber)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[allow(dead_code)] // otherwise compiler complains about Exception not being used
+enum Exception {
+    InstructionMisaligned = 0,
+    InstructionFault = 1,
+    IllegalInstruction = 2,
+    Breakpoint = 3,
+    LoadMisaligned = 4,
+    LoadFault = 5,
+    StoreMisaligned = 6,
+    StoreFault = 7,
+    UserEnvCall = 8,
+    SupervisorEnvCall = 9,
+    MachineEnvCall = 11,
+    InstructionPageFault = 12,
+    LoadPageFault = 13,
+    StorePageFault = 15,
 }

riscv-rt/src/lib.rs

@@ -683,6 +683,8 @@
 #![no_std]
 #![deny(missing_docs)]
 
+extern crate self as riscv_rt; // To use macros that refer to items in this crate.
+
 /// Backwards-compatibility deprecation warnings for renamed feature `no-interrupts`.
 /// If a user enables the old feature, emit a warning pointing them to the new `custom-interrupts`.
 #[cfg(feature = "no-interrupts")]