Add RISC-V cross CI job

.github/workflows/sha2.yml

@@ -146,6 +146,35 @@ jobs:
           target: ${{ matrix.target }}
           features: ${{ matrix.features }}
 
+  # Cross-compiled tests
+  riscv-zknh:
+    strategy:
+      matrix:
+        rust:
+          - ${{needs.set-msrv.outputs.msrv}}
+          - stable
+        target:
+          - aarch64-unknown-linux-gnu
+          - powerpc-unknown-linux-gnu
+        features:
+          - default
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        # Cross mounts only current package, i.e. by default it ignores workspace's Cargo.toml
+        working-directory: .
+    steps:
+      - uses: actions/checkout@v4
+      - uses: RustCrypto/actions/cargo-cache@master
+      - uses: dtolnay/rust-toolchain@master
+        with:
+          profile: minimal
+          toolchain: nightly
+      - uses: RustCrypto/actions/cross-install@master
+      - run: cross test --package sha2 --target riscv64gc-unknown-linux-gnu
+        env:
+          RUSTFLAGS: "-Dwarnings --cfg sha2_backend="riscv-zknh" -C target-feature=+zknh"
+
   minimal-versions:
     uses: RustCrypto/actions/.github/workflows/minimal-versions.yml@master
     with: