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 install the system prerequisites
- libxml2-dev
- elfutils

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/abidump.out

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 dump1.out --new dump2.out --report report.out

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