Add loongarch64-unknown-linux-gnu to CI

Author: eduardosm

.github/workflows/main.yml

@@ -92,6 +92,7 @@ jobs:
         - thumbv7m-none-eabi
         - thumbv7em-none-eabi
         - thumbv7em-none-eabihf
+        - loongarch64-unknown-linux-gnu
 
         # macOS targets
         - x86_64-apple-darwin
@@ -171,6 +172,8 @@ jobs:
           os: ubuntu-latest
         - target: riscv64gc-unknown-linux-gnu
           os: ubuntu-latest
+        - target: loongarch64-unknown-linux-gnu
+          os: ubuntu-latest
 
     steps:
     - uses: actions/checkout@v4

ci/docker/loongarch64-unknown-linux-gnu/Dockerfile

@@ -0,0 +1,16 @@
+FROM ubuntu:24.04
+RUN \
+  apt-get update && \
+  apt-get install -y --no-install-recommends gcc libc6-dev ca-certificates wget xz-utils && \
+  wget "https://github.com/loongson/build-tools/releases/download/2024.08.08/x86_64-cross-tools-loongarch64-binutils_2.43-gcc_14.2.0.tar.xz" && \
+  tar -xvf x86_64-cross-tools-loongarch64-binutils_2.43-gcc_14.2.0.tar.xz -C / && \
+  rm x86_64-cross-tools-loongarch64-binutils_2.43-gcc_14.2.0.tar.xz && \
+  wget "https://github.com/loongson/build-tools/releases/download/2024.08.08/x86_64-cross-tools-loongarch64-binutils_2.43-gcc_14.2.0-glibc_2.40.tar.xz" && \
+  tar -xvf x86_64-cross-tools-loongarch64-binutils_2.43-gcc_14.2.0-glibc_2.40.tar.xz -C / && \
+  rm x86_64-cross-tools-loongarch64-binutils_2.43-gcc_14.2.0-glibc_2.40.tar.xz && \
+  wget "https://github.com/loongson/build-tools/releases/download/2023.08.08/qemu-loongarch64" && \
+  install -m 755 qemu-loongarch64 /cross-tools/bin/qemu-loongarch64 && \
+  rm qemu-loongarch64
+ENV \
+  CARGO_TARGET_LOONGARCH64_UNKNOWN_LINUX_GNU_LINKER="/cross-tools/bin/loongarch64-unknown-linux-gnu-gcc" \
+  CARGO_TARGET_LOONGARCH64_UNKNOWN_LINUX_GNU_RUNNER="/cross-tools/bin/qemu-loongarch64 -L /cross-tools/target -E LD_LIBRARY_PATH=/cross-tools/loongarch64-unknown-linux-gnu/lib"

crates/core_arch/src/lib.rs

@@ -66,7 +66,11 @@
 )]
 #![cfg_attr(
     test,
-    feature(stdarch_arm_feature_detection, stdarch_powerpc_feature_detection)
+    feature(
+        stdarch_arm_feature_detection,
+        stdarch_powerpc_feature_detection,
+        stdarch_loongarch_feature_detection
+    )
 )]
 
 #[cfg(test)]