Added clippy workflow

Author: romancardenas

riscv-rt/.github/workflows/clippy.yaml

@@ -0,0 +1,42 @@
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+  merge_group:
+
+name: Lints compliance check
+
+env:
+  CLIPPY_PARAMS: -W clippy::all -W clippy::pedantic -W clippy::nursery -W clippy::cargo
+
+jobs:
+  clippy:
+    strategy:
+      matrix:
+        toolchain: [ stable, nightly ]
+        cargo_flags:
+          - "--no-default-features"
+          - "--all-features"
+        include:
+          # Nightly is only for reference and allowed to fail
+          - toolchain: nightly
+            experimental: true
+    runs-on: ubuntu-latest
+    continue-on-error: ${{ matrix.experimental || false }}
+    steps:
+      - uses: actions/checkout@v3
+      - uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ matrix.toolchain }}
+          components: clippy
+      - name: Run clippy
+        run: cargo clippy --all ${{ matrix.cargo_flags }} -- -D warnings
+
+   # Job to check that all the lint checks succeeded
+  clippy-check:
+    needs:
+    - clippy
+    runs-on: ubuntu-latest
+    if: always()
+    steps:
+      - run: jq --exit-status 'all(.result == "success")' <<< '${{ toJson(needs) }}'

riscv-rt/CHANGELOG.md

@@ -7,10 +7,15 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+### Added
+
+- New GitHub workflow for checking clippy lints in PRs
+
 ### Changed
 
 - Use inline assembly instead of pre-compiled blobs
 - Removed bors in favor of GitHub Merge Queue
+- `start_trap_rust` is now marked as `unsafe`
 
 ## [v0.11.0] - 2023-01-18
 

riscv-rt/src/lib.rs

@@ -106,9 +106,9 @@
 //! Disassembly of section .text:
 //!
 //! 20000000 <_start>:
-//! 20000000:	800011b7          	lui	gp,0x80001
-//! 20000004:	80018193          	addi	gp,gp,-2048 # 80000800 <_stack_start+0xffffc800>
-//! 20000008:	80004137          	lui	sp,0x80004
+//! 20000000:    800011b7        lui     gp,0x80001
+//! 20000004:    80018193        addi    gp,gp,-2048 # 80000800 <_stack_start+0xffffc800>
+//! 20000008:    80004137        lui     sp,0x80004
 //! ```
 //!
 //! # Symbol interfaces
@@ -393,8 +393,12 @@ extern "C" {
 
 /// Rust entry point (_start_rust)
 ///
-/// Zeros bss section, initializes data section and calls main. This function
-/// never returns.
+/// Zeros bss section, initializes data section and calls main. This function never returns.
+///
+/// # Safety
+///
+/// This function must be called only from assembly `_start` function.
+/// Do **NOT** call this function directly.
 #[link_section = ".init.rust"]
 #[export_name = "_start_rust"]
 pub unsafe extern "C" fn start_rust(a0: usize, a1: usize, a2: usize) -> ! {
@@ -459,29 +463,32 @@ pub struct TrapFrame {
 /// `scause`/`mcause` is read to determine the cause of the trap. XLEN-1 bit indicates
 /// if it's an interrupt or an exception. The result is examined and ExceptionHandler
 /// or one of the core interrupt handlers is called.
+///
+/// # Safety
+///
+/// This function must be called only from assembly `_start_trap` function.
+/// Do **NOT** call this function directly.
 #[link_section = ".trap.rust"]
 #[export_name = "_start_trap_rust"]
-pub extern "C" fn start_trap_rust(trap_frame: *const TrapFrame) {
+pub unsafe extern "C" fn start_trap_rust(trap_frame: *const TrapFrame) {
     extern "C" {
         fn ExceptionHandler(trap_frame: &TrapFrame);
         fn DefaultHandler();
     }
 
-    unsafe {
-        let cause = xcause::read();
-
-        if cause.is_exception() {
-            ExceptionHandler(&*trap_frame)
-        } else if cause.code() < __INTERRUPTS.len() {
-            let h = &__INTERRUPTS[cause.code()];
-            if h.reserved == 0 {
-                DefaultHandler();
-            } else {
-                (h.handler)();
-            }
-        } else {
+    let cause = xcause::read();
+
+    if cause.is_exception() {
+        ExceptionHandler(&*trap_frame)
+    } else if cause.code() < __INTERRUPTS.len() {
+        let h = &__INTERRUPTS[cause.code()];
+        if h.reserved == 0 {
             DefaultHandler();
+        } else {
+            (h.handler)();
         }
+    } else {
+        DefaultHandler();
     }
 }