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Diffstat (limited to 'Documentation/dev-tools/kselftest.rst')
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1 files changed, 121 insertions, 15 deletions
diff --git a/Documentation/dev-tools/kselftest.rst b/Documentation/dev-tools/kselftest.rst index 7756f7a7c23b..25604904fa6e 100644 --- a/Documentation/dev-tools/kselftest.rst +++ b/Documentation/dev-tools/kselftest.rst @@ -7,6 +7,11 @@ directory. These are intended to be small tests to exercise individual code paths in the kernel. Tests are intended to be run after building, installing and booting a kernel. +You can find additional information on Kselftest framework, how to +write new tests using the framework on Kselftest wiki: + +https://kselftest.wiki.kernel.org/ + On some systems, hot-plug tests could hang forever waiting for cpu and memory to be ready to be offlined. A special hot-plug target is created to run the full range of hot-plug tests. In default mode, hot-plug tests run @@ -14,6 +19,10 @@ in safe mode with a limited scope. In limited mode, cpu-hotplug test is run on a single cpu as opposed to all hotplug capable cpus, and memory hotplug test is run on 2% of hotplug capable memory instead of 10%. +kselftest runs as a userspace process. Tests that can be written/run in +userspace may wish to use the `Test Harness`_. Tests that need to be +run in kernel space may wish to use a `Test Module`_. + Running the selftests (hotplug tests are run in limited mode) ============================================================= @@ -31,17 +40,32 @@ To build and run the tests with a single command, use:: Note that some tests will require root privileges. -Build and run from user specific object directory (make O=dir):: +Kselftest supports saving output files in a separate directory and then +running tests. To locate output files in a separate directory two syntaxes +are supported. In both cases the working directory must be the root of the +kernel src. This is applicable to "Running a subset of selftests" section +below. + +To build, save output files in a separate directory with O= :: $ make O=/tmp/kselftest kselftest -Build and run KBUILD_OUTPUT directory (make KBUILD_OUTPUT=):: +To build, save output files in a separate directory with KBUILD_OUTPUT :: + + $ export KBUILD_OUTPUT=/tmp/kselftest; make kselftest - $ make KBUILD_OUTPUT=/tmp/kselftest kselftest +The O= assignment takes precedence over the KBUILD_OUTPUT environment +variable. -The above commands run the tests and print pass/fail summary to make it -easier to understand the test results. Please find the detailed individual -test results for each test in /tmp/testname file(s). +The above commands by default run the tests and print full pass/fail report. +Kselftest supports "summary" option to make it easier to understand the test +results. Please find the detailed individual test results for each test in +/tmp/testname file(s) when summary option is specified. This is applicable +to "Running a subset of selftests" section below. + +To run kselftest with summary option enabled :: + + $ make summary=1 kselftest Running a subset of selftests ============================= @@ -57,17 +81,13 @@ You can specify multiple tests to build and run:: $ make TARGETS="size timers" kselftest -Build and run from user specific object directory (make O=dir):: +To build, save output files in a separate directory with O= :: $ make O=/tmp/kselftest TARGETS="size timers" kselftest -Build and run KBUILD_OUTPUT directory (make KBUILD_OUTPUT=):: +To build, save output files in a separate directory with KBUILD_OUTPUT :: - $ make KBUILD_OUTPUT=/tmp/kselftest TARGETS="size timers" kselftest - -The above commands run the tests and print pass/fail summary to make it -easier to understand the test results. Please find the detailed individual -test results for each test in /tmp/testname file(s). + $ export KBUILD_OUTPUT=/tmp/kselftest; make TARGETS="size timers" kselftest See the top-level tools/testing/selftests/Makefile for the list of all possible targets. @@ -161,11 +181,97 @@ Contributing new tests (details) e.g: tools/testing/selftests/android/config +Test Module +=========== + +Kselftest tests the kernel from userspace. Sometimes things need +testing from within the kernel, one method of doing this is to create a +test module. We can tie the module into the kselftest framework by +using a shell script test runner. ``kselftest_module.sh`` is designed +to facilitate this process. There is also a header file provided to +assist writing kernel modules that are for use with kselftest: + +- ``tools/testing/kselftest/kselftest_module.h`` +- ``tools/testing/kselftest/kselftest_module.sh`` + +How to use +---------- + +Here we show the typical steps to create a test module and tie it into +kselftest. We use kselftests for lib/ as an example. + +1. Create the test module + +2. Create the test script that will run (load/unload) the module + e.g. ``tools/testing/selftests/lib/printf.sh`` + +3. Add line to config file e.g. ``tools/testing/selftests/lib/config`` + +4. Add test script to makefile e.g. ``tools/testing/selftests/lib/Makefile`` + +5. Verify it works: + +.. code-block:: sh + + # Assumes you have booted a fresh build of this kernel tree + cd /path/to/linux/tree + make kselftest-merge + make modules + sudo make modules_install + make TARGETS=lib kselftest + +Example Module +-------------- + +A bare bones test module might look like this: + +.. code-block:: c + + // SPDX-License-Identifier: GPL-2.0+ + + #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + + #include "../tools/testing/selftests/kselftest_module.h" + + KSTM_MODULE_GLOBALS(); + + /* + * Kernel module for testing the foobinator + */ + + static int __init test_function() + { + ... + } + + static void __init selftest(void) + { + KSTM_CHECK_ZERO(do_test_case("", 0)); + } + + KSTM_MODULE_LOADERS(test_foo); + MODULE_AUTHOR("John Developer <jd@fooman.org>"); + MODULE_LICENSE("GPL"); + +Example test script +------------------- + +.. code-block:: sh + + #!/bin/bash + # SPDX-License-Identifier: GPL-2.0+ + $(dirname $0)/../kselftest_module.sh "foo" test_foo + + Test Harness ============ -The kselftest_harness.h file contains useful helpers to build tests. The tests -from tools/testing/selftests/seccomp/seccomp_bpf.c can be used as example. +The kselftest_harness.h file contains useful helpers to build tests. The +test harness is for userspace testing, for kernel space testing see `Test +Module`_ above. + +The tests from tools/testing/selftests/seccomp/seccomp_bpf.c can be used as +example. Example ------- |