Add build-bpf-gcc action

.github/workflows/kernel-build.yml

@@ -46,9 +46,13 @@ jobs:
     timeout-minutes: 100
     env:
         ARTIFACTS_ARCHIVE: "vmlinux-${{ inputs.arch }}-${{ inputs.toolchain_full }}.tar.zst"
+
+        BUILD_BPF_GCC: ${{ inputs.arch == 'x86_64' && 'true' || '' }}
+        BPF_GCC_INSTALL_DIR: ${{ github.workspace }}/bpf-gcc
+
         BPF_NEXT_BASE_BRANCH: 'master'
         BPF_NEXT_FETCH_DEPTH: 64 # A bit of history is needed to facilitate incremental builds
-        BUILD_SCHED_EXT_SELFTESTS: ${{ inputs.arch == 'x86_64' || inputs.arch == 'aarch64' && 'true' || '' }}
+        # BUILD_SCHED_EXT_SELFTESTS: ${{ inputs.arch == 'x86_64' || inputs.arch == 'aarch64' && 'true' || '' }}
         KBUILD_OUTPUT: ${{ github.workspace }}/kbuild-output
         KERNEL: ${{ inputs.kernel }}
         KERNEL_ROOT: ${{ github.workspace }}
@@ -87,23 +91,18 @@ jobs:
           cd ..
           rmdir .kernel
       - uses:  ./patch-kernel
+
         with:
           patches-root: '${{ github.workspace }}/ci/diffs'
           repo-root: ${{ env.REPO_ROOT }}
+
       - name: Setup build environment
         uses: ./setup-build-env
         with:
           arch: ${{ inputs.arch }}
           llvm-version: ${{ inputs.llvm-version }}
           pahole: master
-      - name: Print toolchain version used
-        shell: bash
-        run: |
-          TOOLCHAIN=${{ inputs.toolchain }}
-          if [ $TOOLCHAIN = "llvm" ]; then
-            TOOLCHAIN="clang-${{ inputs.llvm-version }}"
-          fi
-          ${TOOLCHAIN} --version
+
       - name: Build kernel image
         uses: ./build-linux
         with:
@@ -112,11 +111,19 @@ jobs:
           kbuild-output: ${{ env.KBUILD_OUTPUT }}
           max-make-jobs: 32
           llvm-version: ${{ inputs.llvm-version }}
+
+      - if: ${{ env.BUILD_BPF_GCC }}
+        name: Build GCC for BPF selftests
+        uses: theihor/libbpf-ci/build-bpf-gcc@bpf-gcc
+        with:
+          install-dir: ${{ env.BPF_GCC_INSTALL_DIR }}
+
       - name: Build selftests/bpf
         uses: ./build-selftests
         env:
           MAX_MAKE_JOBS: 32
           RELEASE: ${{ inputs.release && '1' || '' }}
+          BPF_GCC: ${{ env.BUILD_BPF_GCC && env.BPF_GCC_INSTALL_DIR || '' }}
         with:
           arch: ${{ inputs.arch }}
           kernel-root: ${{ env.KERNEL_ROOT }}
@@ -133,6 +140,7 @@ jobs:
           toolchain: ${{ inputs.toolchain }}
           llvm-version: ${{ inputs.llvm-version }}
           max-make-jobs: 32
+
       - if: ${{ github.event_name != 'push' }}
         name: Build samples
         uses: ./build-samples
@@ -147,7 +155,7 @@ jobs:
         uses: ./tar-artifacts
         env:
           ARCHIVE_BPF_SELFTESTS: 'true'
-          ARCHIVE_MAKE_HELPERS: ${{ github.repository != 'kernel-patches/bpf' && 'true' || '' }}
+          ARCHIVE_MAKE_HELPERS: 'true'
           ARCHIVE_SCHED_EXT_SELFTESTS: ${{ env.BUILD_SCHED_EXT_SELFTESTS }}
         with:
           arch: ${{ inputs.arch }}

build-bpf-gcc/action.yml

@@ -0,0 +1,32 @@
+name: 'Build BPF GCC'
+description: 'Fetch latest GCC and binutils snapshots, bulid GCC and install into the target directory'
+inputs:
+  install-dir:
+    description: "Path to the GCC installation directory"
+    required: true
+
+runs:
+  using: "composite"
+  steps:
+
+    - name: Determine latest snapshots
+      id: latest-snapshots
+      shell: bash
+      run: ${GITHUB_ACTION_PATH}/latest-snapshots.sh
+
+    - uses: actions/cache@v4
+      id: cache
+      with:
+        path: ${{ inputs.install-dir }}
+        key: BPF-GCC-${{ steps.latest-snapshots.outputs.GCC_BASENAME }}-${{ steps.latest-snapshots.outputs.BINUTILS_BASENAME }}
+
+    - if: steps.cache.outputs.cache-hit != 'true'
+      name: Build BPF GCC
+      env:
+        LOGFILE: /tmp/build-bpf-gcc.log
+      shell: bash
+      run: |
+        ${GITHUB_ACTION_PATH}/build-and-install.sh ${{ inputs.install-dir }} \
+          || { cat $LOGFILE; exit 1; }
+
+

build-bpf-gcc/build-and-install.sh

@@ -0,0 +1,42 @@
+#!/bin/bash
+set -euo pipefail
+
+INSTALLDIR=$(realpath $1)
+LOGFILE=${LOGFILE:-build-bpf-gcc.log}
+
+source ${GITHUB_ACTION_PATH}/.env
+
+test -f $BINUTILS_TARBALL || {
+  echo -n "Fetching $BINUTILS_URL... ";
+  wget -o /dev/null $BINUTILS_URL || { echo -e "\nerror: could not fetch $BINUTILS_URL"; exit 1; };
+  echo done;
+}
+
+test -f $GCC_TARBALL || {
+  echo -n "Fetching $GCC_URL... ";
+  wget -o /dev/null $GCC_URL || { echo -e "\nerror: could not fetch $GCC_URL"; exit 1; };
+  echo done;
+}
+
+if [ ! -f  "${INSTALLDIR}/${BINUTILS_BASENAME}.built" ]; then
+  echo -n "Building and installing $BINUTILS_BASENAME... ";
+  (tar xJf $BINUTILS_TARBALL;
+  cd ${BINUTILS_BASENAME};
+   mkdir build-bpf;
+   cd build-bpf && ../configure --target=bpf-unknown-none --prefix=$INSTALLDIR && make -j $(nproc) && make install && touch ${INSTALLDIR}/${BINUTILS_BASENAME}.built;
+   ) >> $LOGFILE 2>&1 || { echo -e "\nerror: building $BINUTILS_TARBALL"; exit 1; }
+  echo done
+fi
+
+if [ ! -f  "${INSTALLDIR}/${GCC_BASENAME}.built" ]; then
+  echo -n "Building and installing $GCC_BASENAME... ";
+  (tar xJf $GCC_TARBALL;
+   cd ${GCC_BASENAME};
+   ./contrib/download_prerequisites
+   mkdir build-bpf;
+   cd build-bpf && ../configure --target=bpf-unknown-none --prefix=$INSTALLDIR && make -j $(nproc) && make install && touch ${INSTALLDIR}/${GCC_BASENAME}.built;
+   ) >> $LOGFILE 2>&1 || { echo -e "\nerror: building $GCC_TARBALL"; exit 1; }
+  echo done
+fi
+
+exit 0

build-bpf-gcc/latest-snapshots.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+set -euo pipefail
+
+BINUTILS_TARBALL=`wget https://snapshots.sourceware.org/binutils/trunk/latest/src/sha512.sum -O - -o /dev/null | grep -E 'binutils-[0-9a-f.-]+.tar.xz' | sed -e 's/.*\(binutils-[^<]*\).*/\1/'`
+GCC_TARBALL=`wget https://gcc.gnu.org/pub/gcc/snapshots/LATEST-15 -O - -o /dev/null | grep -E 'gcc-15-[0-9]+.tar.xz' | sed -e 's/.*\(gcc-15-[^<]*\).*/\1/'`
+
+BINUTILS_URL="https://snapshots.sourceware.org/binutils/trunk/latest/src/$BINUTILS_TARBALL"
+GCC_URL="https://gcc.gnu.org/pub/gcc/snapshots/LATEST-15/$GCC_TARBALL"
+
+BINUTILS_BASENAME=$(basename $BINUTILS_TARBALL .tar.xz)
+GCC_BASENAME=$(basename $GCC_TARBALL .tar.xz)
+
+cat > ${GITHUB_ACTION_PATH}/.env <<EOF
+BINUTILS_TARBALL=$BINUTILS_TARBALL
+GCC_TARBALL=$GCC_TARBALL
+BINUTILS_URL=$BINUTILS_URL
+GCC_URL=$GCC_URL
+BINUTILS_BASENAME=$BINUTILS_BASENAME
+GCC_BASENAME=$GCC_BASENAME
+EOF
+
+echo "BINUTILS_BASENAME=${BINUTILS_BASENAME}" >> "$GITHUB_OUTPUT"
+echo "GCC_BASENAME=${GCC_BASENAME}" >> "$GITHUB_OUTPUT"
+
+exit 0

build-selftests/action.yml

@@ -18,6 +18,12 @@ inputs:
 runs:
   using: "composite"
   steps:
+
+    - if: ${{ env.BPF_GCC }}
+      uses: ./build-bpf-gcc
+      with:
+        install-dir: ${{ env.BPF_GCC }}
+
     - name: build selftests
       shell: bash
       env:

build-selftests/build_selftests.sh

@@ -25,10 +25,17 @@ if [[ $TOOLCHAIN = "llvm" ]]; then
 	TOOLCHAIN="llvm-$LLVM_VERSION"
 fi
 
+if [ -n "${BPF_GCC:-}" ]; then
+    BPF_GCC="${BPF_GCC}/bin/bpf-unknown-none-gcc"
+else
+    BPF_GCC=
+fi
+
 foldable start build_selftests "Building selftests with $TOOLCHAIN"
 
 MAKE_OPTS=$(cat <<EOF
 	ARCH=${ARCH}
+	BPF_GCC=${BPF_GCC}
 	CROSS_COMPILE=${CROSS_COMPILE}
 	CLANG=clang-${LLVM_VERSION}
 	LLC=llc-${LLVM_VERSION}

setup-build-env/action.yml

@@ -24,7 +24,7 @@ runs:
       run: |
         echo "::group::Setup"
         sudo apt-get update
-        sudo apt-get install -y cmake flex bison build-essential libssl-dev ncurses-dev xz-utils bc rsync libguestfs-tools qemu-kvm qemu-utils zstd libzstd-dev binutils-dev elfutils libcap-dev libelf-dev libdw-dev python3-docutils
+        sudo apt-get install -y cmake flex bison build-essential libssl-dev ncurses-dev xz-utils bc rsync libguestfs-tools qemu-kvm qemu-utils zstd libzstd-dev binutils-dev elfutils libcap-dev libelf-dev libdw-dev python3-docutils texinfo
         echo "::endgroup::"
     - name: Install clang
       shell: bash