ut_SG560D/UM.9.14/device/qcom/kernelscripts/abi

ABI Monitoring Utilities

This directory contains scripts and utilities to compare, track and mitigate changes to the kernel ABI. The comparison framework used is libabigail, but this might change in the future. Follow the instructions below to set up the current prerequisites.

Set up the prerequisites

The script bootstrap will ensure the following system prerequisites are installed. At the moment, only apt based package managers are supported.

• autoconf
• elfutils
• g++
• libtool
• libxml2-dev
• libdw-dev
• make
• pkg-config
• python3

It will then acquire the libabigail sources and build the required binaries. At the very end the script will print instructions how to add the binaries to the local ${PATH} to be used by the remaining utilities.

You can skip this step if your host system provides a suitable version of the libabigail tooling including the binaries abidw and abidiff.

Creating ABI dumps from kernel trees

Provided a linux kernel tree with built vmlinux and kernel modules, the tool dump_abi creates an ABI representation using the selected abi tool. As of now there is only one option: 'libabigail' (default). A sample invocation looks as follows: $ dump_abi --linux-tree path/to/out --out-file /path/to/abi.xml

To ensure a consistent environment and stable toolchain, a wrapper script is provided at the topmost directory of this project: build_abi.sh. It builds the kernel using build.sh and therefore accepts the same environment variables to customize the build, such as BUILD_CONFIG, CC and the various SKIP_* variables to speed up incremental builds. Following a successful build, build_abi.sh will create an ABI dump in the DIST_DIR of the build. A sample invocation from the top of the repo tree looks as follows: $ BUILD_CONFIG=path/to/build.config build/build_abi.sh

Comparing ABI dumps

ABI dumps created by dump_abi can be compared with diff_abi. Ensure to use the same abi-tool for dump_abi and diff_abi. A sample invocation looks as follows: $ diff_abi --baseline abi1.xml --new abi2.xml --report report.out

The report created is tool specific, but generally lists ABI changes detected that affect the Kernel's module interface.

Updating ABI dumps

To update the ABI dump, build_abi.sh can be invoked with the --update flag. It will update the corresponding abi.xml file that is defined via the build.config. It might be useful to invoke the script also with --print-report to print the differences the update cleans up. That information is useful in the commit message when updating the abi.xml in the source control.