diff --git a/Documentation/dev-tools/kunit/faq.rst b/Documentation/dev-tools/kunit/faq.rst index fae426f2634a..b1341c1a62d9 100644 --- a/Documentation/dev-tools/kunit/faq.rst +++ b/Documentation/dev-tools/kunit/faq.rst @@ -25,19 +25,21 @@ disqualifying any of them from being considered unit testing frameworks. Does KUnit support running on architectures other than UML? =========================================================== -Yes, mostly. +Yes. KUnit can run on any architecture, though the kunit.py tool can only +build and run kernels for some architectures (of which UML is the default). -For the most part, the KUnit core framework (what we use to write the tests) -can compile to any architecture. It compiles like just another part of the -kernel and runs when the kernel boots, or when built as a module, when the -module is loaded. However, there is infrastructure, like the KUnit Wrapper -(``tools/testing/kunit/kunit.py``) that might not support some architectures -(see :ref:`kunit-on-qemu`). +You can build and run tests without kunit.py at all on any architecture by +enabling ``CONFIG_KUNIT=y`` and booting the kernel. +See Documentation/dev-tools/kunit/run_manual.rst for more details. -In short, yes, you can run KUnit on other architectures, but it might require -more work than using KUnit on UML. +Alternatively, kunit.py supports many common architectures using +cross-compilers and the qemu emulator. This can be done using the ``--arch`` +parameter when running the tests, and the ``--cross_compile`` parameter +when building (if the architecture is not supported by the host compiler). +See :ref:`kunit-on-qemu` for more details. -For more information, see :ref:`kunit-on-non-uml`. +When writing tests targeting other architectures, it's worth keeping the tips +on the :ref:`kunit-on-non-uml` page in mind. .. _kinds-of-tests: @@ -78,27 +80,30 @@ things to try. down where an issue is occurring. (If you think the parser is at fault, you can run it manually against ``stdin`` or a file with ``kunit.py parse``.) 3. Running the UML kernel directly can often reveal issues or error messages, - ``kunit_tool`` ignores. This should be as simple as running ``./vmlinux`` - after building the UML kernel (for example, by using ``kunit.py build``). + ``kunit_tool`` ignores. This should be as simple as runningi the ``vmlinux`` + binary in the output directory (by default ``./.kunit/vmlinux``) after + building the UML kernel (for example, by using ``kunit.py build``). Note that UML has some unusual requirements (such as the host having a tmpfs filesystem mounted), and has had issues in the past when built statically and the host has KASLR enabled. (On older host kernels, you may need to run ``setarch `uname -m` -R ./vmlinux`` to disable KASLR.) -4. Make sure the kernel .config has ``CONFIG_KUNIT=y`` and at least one test +4. Try running KUnit on a different architecture by using the ``--arch`` + option. On an x86_64 host, using ``--arch=x86_64`` is a good first step. +5. Make sure the kernel .config has ``CONFIG_KUNIT=y`` and at least one test (e.g. ``CONFIG_KUNIT_EXAMPLE_TEST=y``). kunit_tool will keep its .config around, so you can see what config was used after running ``kunit.py run``. It also preserves any config changes you might make, so you can enable/disable things with ``make ARCH=um menuconfig`` or similar, and then re-run kunit_tool. -5. Try to run ``make ARCH=um defconfig`` before running ``kunit.py run``. This +6. Try to run ``make ARCH=um defconfig`` before running ``kunit.py run``. This may help clean up any residual config items which could be causing problems. -6. Finally, try running KUnit outside UML. KUnit and KUnit tests can be - built into any kernel, or can be built as a module and loaded at runtime. - Doing so should allow you to determine if UML is causing the issue you're - seeing. When tests are built-in, they will execute when the kernel boots, and +7. Finally, try running KUnit manually, instead of via ``kunit.py``. KUnit can + be built into any kernel, or can be built as a module and loaded at runtime. + When tests are built-in, they will execute when the kernel boots, and modules will automatically execute associated tests when loaded. Test results can be collected from ``/sys/kernel/debug/kunit//results``, and - can be parsed with ``kunit.py parse``. For more details, see :ref:`kunit-on-qemu`. + can be parsed with ``kunit.py parse``. For more details, see + Documentation/dev-tools/kunit/run_manual.rst If none of the above tricks help, you are always welcome to email any issues to kunit-dev@googlegroups.com.