From ea08eeccae9297f7aabd2ef7f0c2517ac4549acc Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:18:26 +0000
Subject: [PATCH] write in 30M
---
kernel/Documentation/dev-tools/kselftest.rst | 213 ++++++++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 184 insertions(+), 29 deletions(-)
diff --git a/kernel/Documentation/dev-tools/kselftest.rst b/kernel/Documentation/dev-tools/kselftest.rst
index 6f653ac..a901def 100644
--- a/kernel/Documentation/dev-tools/kselftest.rst
+++ b/kernel/Documentation/dev-tools/kselftest.rst
@@ -7,12 +7,21 @@
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 full range of hot-plug tests. In default mode, hot-plug tests run
+to run the full range of hot-plug tests. In default mode, hot-plug tests run
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 @@
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 ::
- $ make KBUILD_OUTPUT=/tmp/kselftest kselftest
+ $ export KBUILD_OUTPUT=/tmp/kselftest; make 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).
+The O= assignment takes precedence over the KBUILD_OUTPUT environment
+variable.
+
+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 +81,29 @@
$ 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
+ $ export KBUILD_OUTPUT=/tmp/kselftest; make 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).
+Additionally you can use the "SKIP_TARGETS" variable on the make command
+line to specify one or more targets to exclude from the TARGETS list.
+
+To run all tests but a single subsystem::
+
+ $ make -C tools/testing/selftests SKIP_TARGETS=ptrace run_tests
+
+You can specify multiple tests to skip::
+
+ $ make SKIP_TARGETS="size timers" kselftest
+
+You can also specify a restricted list of tests to run together with a
+dedicated skiplist::
+
+ $ make TARGETS="bpf breakpoints size timers" SKIP_TARGETS=bpf kselftest
See the top-level tools/testing/selftests/Makefile for the list of all
possible targets.
@@ -89,31 +125,63 @@
Install selftests
=================
-You can use kselftest_install.sh tool installs selftests in default
-location which is tools/testing/selftests/kselftest or a user specified
-location.
+You can use the "install" target of "make" (which calls the `kselftest_install.sh`
+tool) to install selftests in the default location (`tools/testing/selftests/kselftest_install`),
+or in a user specified location via the `INSTALL_PATH` "make" variable.
To install selftests in default location::
- $ cd tools/testing/selftests
- $ ./kselftest_install.sh
+ $ make -C tools/testing/selftests install
To install selftests in a user specified location::
- $ cd tools/testing/selftests
- $ ./kselftest_install.sh install_dir
+ $ make -C tools/testing/selftests install INSTALL_PATH=/some/other/path
Running installed selftests
===========================
-Kselftest install as well as the Kselftest tarball provide a script
-named "run_kselftest.sh" to run the tests.
+Found in the install directory, as well as in the Kselftest tarball,
+is a script named `run_kselftest.sh` to run the tests.
-You can simply do the following to run the installed Kselftests. Please
+You can simply do the following to run the installed Kselftests. Please
note some tests will require root privileges::
- $ cd kselftest
+ $ cd kselftest_install
$ ./run_kselftest.sh
+
+To see the list of available tests, the `-l` option can be used::
+
+ $ ./run_kselftest.sh -l
+
+The `-c` option can be used to run all the tests from a test collection, or
+the `-t` option for specific single tests. Either can be used multiple times::
+
+ $ ./run_kselftest.sh -c bpf -c seccomp -t timers:posix_timers -t timer:nanosleep
+
+For other features see the script usage output, seen with the `-h` option.
+
+Packaging selftests
+===================
+
+In some cases packaging is desired, such as when tests need to run on a
+different system. To package selftests, run::
+
+ $ make -C tools/testing/selftests gen_tar
+
+This generates a tarball in the `INSTALL_PATH/kselftest-packages` directory. By
+default, `.gz` format is used. The tar compression format can be overridden by
+specifying a `FORMAT` make variable. Any value recognized by `tar's auto-compress`_
+option is supported, such as::
+
+ $ make -C tools/testing/selftests gen_tar FORMAT=.xz
+
+`make gen_tar` invokes `make install` so you can use it to package a subset of
+tests by using variables specified in `Running a subset of selftests`_
+section::
+
+ $ make -C tools/testing/selftests gen_tar TARGETS="bpf" FORMAT=.xz
+
+.. _tar's auto-compress: https://www.gnu.org/software/tar/manual/html_node/gzip.html#auto_002dcompress
Contributing new tests
======================
@@ -139,7 +207,7 @@
default.
TEST_CUSTOM_PROGS should be used by tests that require custom build
- rule and prevent common build rule use.
+ rules and prevent common build rule use.
TEST_PROGS are for test shell scripts. Please ensure shell script has
its exec bit set. Otherwise, lib.mk run_tests will generate a warning.
@@ -159,13 +227,99 @@
* If a test needs specific kernel config options enabled, add a config file in
the test directory to enable them.
- e.g: tools/testing/selftests/android/ion/config
+ 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
-------
@@ -179,7 +333,8 @@
.. kernel-doc:: tools/testing/selftests/kselftest_harness.h
:functions: TH_LOG TEST TEST_SIGNAL FIXTURE FIXTURE_DATA FIXTURE_SETUP
- FIXTURE_TEARDOWN TEST_F TEST_HARNESS_MAIN
+ FIXTURE_TEARDOWN TEST_F TEST_HARNESS_MAIN FIXTURE_VARIANT
+ FIXTURE_VARIANT_ADD
Operators
---------
--
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