ci: Test powerpc64-unknown-linux-musl in tier 2

.github/workflows/ci.yaml

@@ -217,6 +217,10 @@ jobs:
             env: { TEST_MUSL_V1_2_3: 1 }
             artifact-tag: new-musl
           - target: powerpc64-unknown-linux-gnu
+          - target: powerpc64-unknown-linux-musl
+          - target: powerpc64-unknown-linux-musl
+            env: { RUST_LIBC_UNSTABLE_MUSL_V1_2_3: 1 }
+            artifact-tag: new-musl
           - target: powerpc64le-unknown-linux-gnu
           - target: powerpc64le-unknown-linux-musl
           - target: powerpc64le-unknown-linux-musl

Cargo.toml

@@ -39,6 +39,7 @@ targets = [
     "loongarch64-unknown-linux-musl",
     "powerpc-unknown-linux-gnu",
     "powerpc64-unknown-linux-gnu",
+    "powerpc64-unknown-linux-musl",
     "powerpc64le-unknown-linux-gnu",
     "powerpc64le-unknown-linux-musl",
     "riscv64gc-unknown-linux-gnu",
@@ -126,7 +127,6 @@ targets = [
     "powerpc64-ibm-aix",
     "powerpc64-unknown-freebsd",
     "powerpc64-unknown-linux-gnu",
-    "powerpc64-unknown-linux-musl",
     "powerpc64-wrs-vxworks",
     "riscv32-wrs-vxworks",
     "riscv32gc-unknown-linux-musl",

ci/docker/powerpc64-unknown-linux-musl/Dockerfile

@@ -0,0 +1,34 @@
+FROM ubuntu:25.04
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    ca-certificates \
+    curl \
+    gcc \
+    gcc-powerpc64-linux-gnu \
+    git \
+    libc6-dev \
+    make \
+    patch \
+    qemu-user \
+    rsync \
+    xz-utils
+
+RUN curl -O https://static.rust-lang.org/dist/2026-06-26/rust-std-nightly-powerpc64-unknown-linux-musl.tar.xz && \
+    tar xf rust-std-nightly-powerpc64-unknown-linux-musl.tar.xz && \
+    find rust-std-nightly-powerpc64-unknown-linux-musl/ -name libcompiler_builtins*.rlib -exec sh -c "cp {} /compiler_builtins.rlib" \;
+
+ARG MUSL_VERSION
+COPY install-musl.sh /
+RUN /install-musl.sh powerpc64 "$MUSL_VERSION"
+
+# Rust's unwind unconditionally links to libgcc_s.so.1
+# We instead get the unwinding symbols from the self-contained libunwind.a
+# since that's included in the toolchain
+RUN touch /musl-powerpc64/lib/libgcc_s.so.1
+
+ENV PATH=$PATH:/musl-powerpc64/bin:/rust/bin \
+    CC_powerpc64_unknown_linux_musl=musl-gcc \
+    CFLAGS_powerpc64_unknown_linux_musl="-mabi=elfv2" \
+    CARGO_TARGET_POWERPC64_UNKNOWN_LINUX_MUSL_LINKER=musl-gcc \
+    CARGO_TARGET_POWERPC64_UNKNOWN_LINUX_MUSL_RUNNER="qemu-ppc64 -L /musl-powerpc64" \
+    EXTRA_RUSTFLAGS="-Clink-args=-lunwind -Clink-self-contained=yes -L /musl-powerpc64/lib"

ci/install-musl.sh

@@ -80,10 +80,21 @@ case ${1} in
             ./configure --prefix="/musl-${musl_arch}" --enable-wrapper=yes
         make install -j4
         ;;
-    powerpc64*)
+    powerpc64le)
         musl_arch=powerpc64
         kernel_arch=powerpc
-        CC="${1}-linux-gnu-gcc" CFLAGS="-mlong-double-64" \
+        CC=powerpc64le-linux-gnu-gcc CFLAGS="-mlong-double-64" \
+            ./configure --prefix="/musl-${musl_arch}" --enable-wrapper=yes
+        make install -j4
+        ;;
+    powerpc64)
+        musl_arch=powerpc64
+        kernel_arch=powerpc
+        # Ubuntu's powerpc64 cross toolchain is for ELFv1, but we need a
+        # libgcc that's for ELFv2, which we can't trivially get.
+        # Luckily, compiler-builtins provides all the necessary symbols,
+        # so we resort to using that instead
+        CC=powerpc64-linux-gnu-gcc CFLAGS="-mlong-double-64 -mabi=elfv2" LIBCC="/compiler_builtins.rlib" \
             ./configure --prefix="/musl-${musl_arch}" --enable-wrapper=yes
         make install -j4
         ;;

ci/verify-build.py

@@ -103,6 +103,7 @@ class TargetResult:
     Target("loongarch64-unknown-linux-musl", min_toolchain=Toolchain.STABLE),
     Target("powerpc-unknown-linux-gnu"),
     Target("powerpc64-unknown-linux-gnu"),
+    Target("powerpc64-unknown-linux-musl", min_toolchain=Toolchain.STABLE),
     Target("powerpc64le-unknown-linux-gnu"),
     Target("powerpc64le-unknown-linux-musl", min_toolchain=Toolchain.STABLE),
     Target("riscv64gc-unknown-linux-gnu"),
@@ -188,7 +189,6 @@ class TargetResult:
     Target("powerpc-wrs-vxworks-spe", dist=False),
     Target("powerpc64-ibm-aix", dist=False),
     Target("powerpc64-unknown-freebsd", dist=False),
-    Target("powerpc64-unknown-linux-musl", dist=False),
     Target("powerpc64-wrs-vxworks", dist=False),
     Target("riscv32-wrs-vxworks", dist=False),
     Target("riscv32gc-unknown-linux-gnu", dist=False),