kernel-build.yml

name: Reusable build workflow

on:
  workflow_call:
    inputs:
      arch:
        required: true
        type: string
        description: The architecture to build against, e.g x86_64, aarch64, s390x...
      toolchain_full:
        required: true
        type: string
        description: The toolchain and for llvm, its version, e.g gcc, llvm-15
      toolchain:
        required: true
        type: string
        description: The toolchain, e.g gcc, llvm
      runs_on:
        required: true
        type: string
        description: The runners to run the test on. This is a json string representing an array of labels.
      llvm-version:
        required: true
        type: string
        description: The version of LLVM used to build selftest.... for llvm toolchain, this should match the one from toolchain_full, for gcc it is an arbritrary version we decide to build selftests against.
      kernel:
        required: true
        type: string
        description: The kernel to run the test against. For KPD this is always LATEST, which runs against a newly built kernel.
      download_sources:
        required: true
        type: boolean
        description: Whether to download the linux sources into the working directory.
        default: false
      release:
        required: false
        type: boolean
        description: Build selftest with -O2 optimization
        default: false

jobs:
  build:
    name: build for ${{ inputs.arch }} with ${{ inputs.toolchain_full }}${{ inputs.release && ' and -O2 optimization' || '' }}
    runs-on: ${{ fromJSON(inputs.runs_on) }}
    timeout-minutes: 100
    env:
        KERNEL: ${{ inputs.kernel }}
        REPO_ROOT: ${{ github.workspace }}
        REPO_PATH: ""
        KBUILD_OUTPUT: kbuild-output/
    steps:
      - uses: actions/checkout@v4
        # We fetch an actual bit of history here to facilitate incremental
        # builds (which may check out some earlier upstream change).
        with:
          fetch-depth: 50
      - if: ${{ inputs.download_sources }}
        name: Download bpf-next tree
        uses: libbpf/ci/get-linux-source@main
        with:
          dest: '.kernel'
      - if: ${{ inputs.download_sources }}
        name: Move linux source in place
        shell: bash
        run: |
          rm -rf .kernel/.git
          cp -rf .kernel/. .
          rm -rf .kernel
      - name: Get commit meta-data
        id: get-commit-metadata
        run: |
          bash .github/scripts/get-commit-metadata.sh
      - name: Pull recent KBUILD_OUTPUT contents
        uses: actions/cache@v4
        with:
          path: ${{ env.KBUILD_OUTPUT }}
          key: kbuild-output-${{ inputs.arch }}-${{ inputs.toolchain_full }}-${{ steps.get-commit-metadata.outputs.branch }}-${{ steps.get-commit-metadata.outputs.timestamp }}-${{ steps.get-commit-metadata.outputs.commit }}
          restore-keys: |
            kbuild-output-${{ inputs.arch }}-${{ inputs.toolchain_full }}-${{ steps.get-commit-metadata.outputs.branch }}-${{ steps.get-commit-metadata.outputs.timestamp }}-
            kbuild-output-${{ inputs.arch }}-${{ inputs.toolchain_full }}-${{ steps.get-commit-metadata.outputs.branch }}-
            kbuild-output-${{ inputs.arch }}-${{ inputs.toolchain_full }}-
      - name: Prepare incremental build
        shell: bash
        run: |
          bash .github/scripts/prepare-incremental-builds.sh ${{ steps.get-commit-metadata.outputs.commit }}
      - uses: libbpf/ci/patch-kernel@main
        with:
          patches-root: '${{ github.workspace }}/ci/diffs'
          repo-root: '${{ github.workspace }}'
      - name: Setup build environment
        uses: libbpf/ci/setup-build-env@main
        with:
          arch: ${{ inputs.arch }}
          llvm-version: ${{ inputs.llvm-version }}
      - name: Build kernel image
        uses: libbpf/ci/build-linux@main
        with:
          arch: ${{ inputs.arch }}
          toolchain: ${{ inputs.toolchain }}
          kbuild-output: ${{ env.KBUILD_OUTPUT }}
          max-make-jobs: 32
          llvm-version: ${{ inputs.llvm-version }}
      - name: Build selftests
        uses: libbpf/ci/build-selftests@main
        with:
          arch: ${{ inputs.arch }}
          toolchain: ${{ inputs.toolchain }}
          kbuild-output: ${{ env.KBUILD_OUTPUT }}
          max-make-jobs: 32
          llvm-version: ${{ inputs.llvm-version }}
        env:
          # RELEASE= disables all optimizaions
          # RELEASE=0 adds -O0 make flag
          # RELEASE=1 adds -O2 make flag
          RELEASE: ${{ inputs.release && '1' || '' }}
      - if: ${{ github.event_name != 'push' }}
        name: Build samples
        uses: libbpf/ci/build-samples@main
        with:
          arch: ${{ inputs.arch }}
          toolchain: ${{ inputs.toolchain }}
          kbuild-output: ${{ env.KBUILD_OUTPUT }}
          max-make-jobs: 32
          llvm-version: ${{ inputs.llvm-version }}
      - name: Tar artifacts
        run: |
          bash .github/scripts/tar-artifact.sh ${{ inputs.arch }} ${{ inputs.toolchain_full }}
      - if: ${{ github.event_name != 'push' }}
        name: Remove KBUILD_OUTPUT content
        shell: bash
        run: |
          # Remove $KBUILD_OUTPUT to prevent cache creation for pull requests.
          # Only on pushed changes are build artifacts actually cached, because
          # of github.com/actions/cache's cache isolation logic.
          rm -rf "${KBUILD_OUTPUT}"
      - uses: actions/upload-artifact@v4
        with:
          name: vmlinux-${{ inputs.arch }}-${{ inputs.toolchain_full }}${{ inputs.release && '-release' || '' }}
          if-no-files-found: error
          path: vmlinux-${{ inputs.arch }}-${{ inputs.toolchain_full }}.tar.zst