User/namjain/reprobuild gh testing#143
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Add NixOS flake configuration and helper scripts for reproducible kernel builds. Files added: - flake.nix: Nix environment with pinned toolchain (GCC 13.2.0, binutils, etc.) - flake.lock: Locked package versions for reproducibility - Microsoft/nix-setup.sh: One-time Nix installation helper - Microsoft/nix-clean.sh: Build artifact cleanup - .gitignore: Add Nix-related entries This establishes the foundation for bit-reproducible kernel builds across different machines by providing a hermetic build environment with pinned dependencies. Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
Add nix-build.sh that orchestrates reproducible kernel builds using the Nix environment established in the previous commit. Features: - Pure Nix environment with --ignore-environment flag - Fixed build paths for reproducible absolute path embeddings - Reproducible environment variables: - SOURCE_DATE_EPOCH= timestamp of top git commit embedded - KBUILD_BUILD_USER=builder - KBUILD_BUILD_HOST=nixos - KBUILD_BUILD_VERSION=1 - Copies source to fixed path to ensure identical embedded paths - Invokes build-hcl-kernel.sh within the controlled environment - Copies artifacts back to original location - Cleanup on exit Usage: ./Microsoft/nix-build.sh x64 # Build x64 kernel ./Microsoft/nix-build.sh arm64 # Build arm64 kernel ./Microsoft/nix-build.sh x64 cvm # Build x64 cvm kernel ./Microsoft/nix-build.sh arm64 cvm # Build arm64 cvm kernel Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
Enhance build-hcl-kernel.sh to support reproducible builds when invoked from nix-build.sh or other reproducible environments. Changes: - Detect host architecture to avoid unnecessary cross-compilation - Set CC explicitly to gcc/cross-compiler for Nix toolchain - Add LOCALVERSION= to prevent '+' suffix in version string - Add KCFLAGS=-fdebug-prefix-map to normalize debug paths - Add SHA256 checksum output of vmlinux for verification - Remove KBUILD_BUILD_ID=none (not needed) When REPRODUCIBLE_BUILD=1: - Uses Nix's gcc instead of system gcc for native builds - Only uses cross-compiler when actually cross-compiling - Ensures consistent compiler identification in kernel binary Otherwise, let users continue using this script for dev work as before. Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
Add build-hcl-kernel-pipeline.sh for Azure DevOps CI integration with reproducible build support. Features: - Supports amd64 and arm64 architectures - CVM config merge support via merge_cvm_config() - Optional reproducible build mode (--reproducible flag) - Generates kernel, headers, modules, and debug symbols - Progress indicators for build stages [1/5] through [5/5] - SHA256 checksum output for reproducibility verification Key differences from build-hcl-kernel.sh: - Standalone script that doesn't depend on nix-build.sh wrapper - Implements complete build workflow in one script - Uses KBUILD_OUTPUT=$BUILD_DIR/linux subdirectory structure - Handles CVM config merging inline - Moves artifacts from /linux subdirectory to BUILD_DIR root for pipeline - When --reproducible: sets up Nix environment and reproducible variables Build directory structure: - $BUILD_DIR/linux/ # KBUILD_OUTPUT during build - $BUILD_DIR/vmlinux # Final artifacts at root - $BUILD_DIR/linux-headers/ - $BUILD_DIR/debug_symbols/ Usage: ./build-hcl-kernel-pipeline.sh -s <source> -b <build> -c <config> -a <arch> ./build-hcl-kernel-pipeline.sh ... --reproducible ./build-hcl-kernel-pipeline.sh ... --cvm-config <config> Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
Use the Nix-pinned toolchain in build_linux so x64, cvm-x64, and arm64 produce deterministic outputs for a given commit. - Build via Microsoft/build-hcl-kernel-pipeline.sh --reproducible. - Set SOURCE_DATE_EPOCH from the commit timestamp. - Add Microsoft/package-ci-artifacts.sh for deterministic packaging and sha256 reporting. - Keep build_perf and create_release behavior unchanged.
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| name: Build Linux kernel (reproducible, run ${{ matrix.repro_run }}) | ||
| runs-on: ubuntu-latest | ||
| strategy: | ||
| fail-fast: false | ||
| matrix: | ||
| arch: ['x64', 'cvm-x64', 'arm64'] | ||
| repro_run: [1, 2] | ||
| env: | ||
| # Stable build identity used to derive SOURCE_DATE_EPOCH and metadata. | ||
| KBUILD_BUILD_USER: builder | ||
| KBUILD_BUILD_HOST: nixos | ||
| steps: | ||
| - name: Checkout source | ||
| uses: actions/checkout@v4 | ||
| with: | ||
| # Need the HEAD commit's timestamp for SOURCE_DATE_EPOCH; depth=1 is sufficient. | ||
| fetch-depth: 1 | ||
|
|
||
| - name: Install dependencies | ||
| run: | | ||
| sudo apt-get update | ||
| sudo apt-get install -y build-essential libncurses-dev bison flex libssl-dev libelf-dev | ||
| [ "${{ matrix.arch }}" == "arm64" ] && sudo apt-get install -y gcc-aarch64-linux-gnu || true | ||
| - name: Install Nix | ||
| uses: cachix/install-nix-action@v27 | ||
| with: | ||
| extra_nix_config: | | ||
| experimental-features = nix-command flakes | ||
| accept-flake-config = true | ||
|
|
||
| - name: Build kernel | ||
| - name: Map ci arch to build args | ||
| id: args | ||
| run: | | ||
| if [ "${{ matrix.arch }}" == "x64" ] || [ "${{ matrix.arch }}" == "cvm-x64" ]; then | ||
| export makeargs="ARCH=x86_64 KCONFIG_CONFIG=Microsoft/hcl-x64.config INSTALL_MOD_PATH=$PWD/out/modules" | ||
| export targets="olddefconfig vmlinux modules modules_install" | ||
| elif [ "${{ matrix.arch }}" == "arm64" ]; then | ||
| export makeargs="ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- KCONFIG_CONFIG=Microsoft/hcl-arm64.config INSTALL_MOD_PATH=$PWD/out/modules" | ||
| export targets="olddefconfig vmlinux Image modules modules_install" | ||
| fi | ||
| case "${{ matrix.arch }}" in | ||
| x64) | ||
| echo "build_arch=amd64" >> "$GITHUB_OUTPUT" | ||
| echo "config=Microsoft/hcl-x64.config" >> "$GITHUB_OUTPUT" | ||
| echo "is_cvm=0" >> "$GITHUB_OUTPUT" | ||
| ;; | ||
| cvm-x64) | ||
| echo "build_arch=amd64" >> "$GITHUB_OUTPUT" | ||
| echo "config=Microsoft/hcl-x64.config" >> "$GITHUB_OUTPUT" | ||
| echo "is_cvm=1" >> "$GITHUB_OUTPUT" | ||
| ;; | ||
| arm64) | ||
| echo "build_arch=arm64" >> "$GITHUB_OUTPUT" | ||
| echo "config=Microsoft/hcl-arm64.config" >> "$GITHUB_OUTPUT" | ||
| echo "is_cvm=0" >> "$GITHUB_OUTPUT" | ||
| ;; | ||
| esac | ||
|
|
||
| [ "${{ matrix.arch }}" == "cvm-x64" ] && ./Microsoft/merge-cvm-config.sh | ||
| make $makeargs -j$(nproc) $targets | ||
| - name: Merge CVM config fragment | ||
| if: steps.args.outputs.is_cvm == '1' | ||
| run: | | ||
| # Run the merge inside the Nix dev shell so flex/bison/gcc are present | ||
| # and so that scripts/kconfig builds against the same toolchain that | ||
| # will be used for the actual kernel compile. | ||
| nix develop -i \ | ||
| -k HOME -k USER -k TERM \ | ||
| --command bash -ec './Microsoft/merge-cvm-config.sh' | ||
|
|
||
| - name: Prepare for packaging | ||
| - name: Build kernel reproducibly | ||
| env: | ||
| # SOURCE_DATE_EPOCH is derived from the HEAD commit by the pipeline | ||
| # script when not pre-set; exporting it here makes it visible in logs. | ||
| GIT_SHA: ${{ github.sha }} | ||
| run: | | ||
| export artifacts_dir="release_artifacts/${{ matrix.arch }}" | ||
| if [ "${{ matrix.arch }}" == "arm64" ]; then | ||
| export objcopy="aarch64-linux-gnu-objcopy" | ||
| else | ||
| export objcopy="objcopy" | ||
| fi | ||
| # The pipeline script copies the source into /tmp/ohcl-kernel-build/src | ||
| # to normalise embedded paths. Place the build dir OUTSIDE the source | ||
| # so it survives that rsync (which excludes ./build, ./out, ./compare). | ||
| BUILD_DIR="${RUNNER_TEMP:-/tmp}/build-output-${{ matrix.arch }}-run${{ matrix.repro_run }}" | ||
| rm -rf "$BUILD_DIR" | ||
| mkdir -p "$BUILD_DIR" | ||
| echo "BUILD_DIR=$BUILD_DIR" >> "$GITHUB_ENV" | ||
|
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| mkdir -p $artifacts_dir | ||
| cp vmlinux $artifacts_dir | ||
| $objcopy --only-keep-debug --compress-debug-sections $artifacts_dir/vmlinux $artifacts_dir/vmlinux.dbg | ||
| $objcopy --strip-all --add-gnu-debuglink=$artifacts_dir/vmlinux.dbg $artifacts_dir/vmlinux | ||
| [ "${{ matrix.arch }}" == "arm64" ] && cp arch/arm64/boot/Image $artifacts_dir/Image || true | ||
| export SOURCE_DATE_EPOCH="$(git log -1 --pretty=%ct)" | ||
| echo "SOURCE_DATE_EPOCH=$SOURCE_DATE_EPOCH" | ||
| echo "SOURCE_DATE_EPOCH=$SOURCE_DATE_EPOCH" >> "$GITHUB_ENV" | ||
|
|
||
| if [ "${{ matrix.arch }}" == "cvm-x64" ]; then | ||
| cp Microsoft/hcl-x64.config $artifacts_dir/kernel_config | ||
| else | ||
| cp Microsoft/hcl-${{ matrix.arch }}.config $artifacts_dir/kernel_config | ||
| fi | ||
| ./Microsoft/build-hcl-kernel-pipeline.sh \ | ||
| --source-dir "$PWD" \ | ||
| --build-dir "$BUILD_DIR" \ | ||
| --config "${{ steps.args.outputs.config }}" \ | ||
| --arch "${{ steps.args.outputs.build_arch }}" \ | ||
| --reproducible | ||
|
|
||
| echo "{" > $artifacts_dir/kernel_build_metadata.json | ||
| echo " \"git_branch\": \"${{ github.ref_name }}\"," >> $artifacts_dir/kernel_build_metadata.json | ||
| echo " \"git_revision\": \"${{ github.sha }}\"," >> $artifacts_dir/kernel_build_metadata.json | ||
| echo " \"build_id\": \"${{ github.run_id }}\"," >> $artifacts_dir/kernel_build_metadata.json | ||
| echo " \"build_name\": \"$(date +"%Y%m%d")\"" >> $artifacts_dir/kernel_build_metadata.json | ||
| echo "}" >> $artifacts_dir/kernel_build_metadata.json | ||
|
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| mv out/modules/lib/modules/*/ $artifacts_dir/modules | ||
| rm $artifacts_dir/modules/build | ||
| mkdir $artifacts_dir/modules/debug-files/ | ||
| find $artifacts_dir/modules -name '*.ko' | while read -r mod; do | ||
| export outmod="$artifacts_dir/modules/debug-files/$(basename $mod)" | ||
| $objcopy --only-keep-debug --compress-debug-sections "$mod" "$outmod.dbg" | ||
| $objcopy --strip-unneeded --add-gnu-debuglink "$outmod.dbg" "$mod" | ||
| done | ||
| - name: Package artifacts | ||
| run: | | ||
| # Packaging runs inside the Nix shell so the cross objcopy is on PATH | ||
| # for arm64 module stripping. | ||
| nix develop -i \ | ||
| -k HOME -k USER -k TERM \ | ||
| -k BUILD_DIR \ | ||
| --command bash -ec ' | ||
| bash ./Microsoft/package-ci-artifacts.sh \ | ||
| "$BUILD_DIR" \ | ||
| "${{ matrix.arch }}" \ | ||
| "$PWD" \ | ||
| "$PWD/release_artifacts" \ | ||
| "${{ github.ref_name }}" \ | ||
| "${{ github.sha }}" \ | ||
| "${{ github.run_id }}" | ||
| ' | ||
|
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| - name: Print reproducibility hashes | ||
| run: | | ||
| ART="release_artifacts/${{ matrix.arch }}" | ||
| echo "## Reproducibility hashes (${{ matrix.arch }} / run ${{ matrix.repro_run }})" >> "$GITHUB_STEP_SUMMARY" | ||
| echo '```' >> "$GITHUB_STEP_SUMMARY" | ||
| ( cd "$ART" && sha256sum vmlinux vmlinux.dbg kernel_config \ | ||
| $( [ -f Image ] && echo Image ) ) | tee -a "$GITHUB_STEP_SUMMARY" | ||
| echo '```' >> "$GITHUB_STEP_SUMMARY" | ||
|
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| - name: Upload build artifacts | ||
| uses: actions/upload-artifact@v4 | ||
| with: | ||
| name: ${{ matrix.arch }}-build | ||
| name: ${{ matrix.arch }}-build-run${{ matrix.repro_run }} | ||
| path: release_artifacts/${{ matrix.arch }}/ | ||
|
|
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| compare_repro: |
- Build each Linux arch variant twice in parallel (run1/run2) - Preserve per-run logs and artifact uploads - Add compare_repro job to diff full artifact hashes across runs - Keep release creation tag-gated and publish artifacts from run1
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