kunit: Allow kunit test modules to use test filtering

External tools, e.g., Intel GPU tools (IGT), support execution of
individual selftests provided by kernel modules. That could be also
applicable to kunit test modules if they provided test filtering. But
test filtering is now possible only when kunit code is built into the
kernel. Moreover, a filter can be specified only at boot time, then
reboot is required each time a different filter is needed.

Build the test filtering code also when kunit is configured as a module,
expose test filtering functions to other kunit source files, and use them
in kunit module notifier callback functions. Userspace can then reload
the kunit module with a value of the filter_glob parameter tuned to a
specific kunit test module every time it wants to limit the scope of tests
executed on that module load. Make the kunit.filter* parameters visible
in sysfs for user convenience.

v5: Refresh on tpp of attributes filtering fix
v4: Refresh on top of newly applied attributes patches and changes
introdced by new versions of other patches submitted in series with
this one.
v3: Fix CONFIG_GLOB, required by filtering functions, not selected when
building as a module (lkp@intel.com).
v2: Fix new name of a structure moved to kunit namespace not updated
across all uses (lkp@intel.com).

Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: add kunit.enable to enable/disable KUnit test

This patch adds the kunit.enable module parameter that will need to be
set to true in addition to KUNIT being enabled for KUnit tests to run.
The default value is true giving backwards compatibility. However, for
the production+testing use case the new config option
KUNIT_DEFAULT_ENABLED can be set to N requiring the tester to opt-in
by passing kunit.enable=1 to the kernel.

Signed-off-by: Joe Fradley <joefradley@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: add kunit.filter_glob cmdline option to filter suites

E.g. specifying this would run suites with "list" in their name.
kunit.filter_glob=list*

Note: the executor prints out a TAP header that includes the number of
suites we intend to run.
So unless we want to report empty results for filtered-out suites, we
need to do the filtering here in the executor.
It's also probably better in the executor since we most likely don't
want any filtering to apply to tests built as modules.

This code does add a CONFIG_GLOB=y dependency for CONFIG_KUNIT=y.
But the code seems light enough that it shouldn't be an issue.

For now, we only filter on suite names so we don't have to create copies
of the suites themselves, just the array (of arrays) holding them.

The name is rather generic since in the future, we could consider
extending it to a syntax like:
kunit.filter_glob=<suite_glob>.<test_glob>
E.g. to run all the del list tests
kunit.filter_glob=list-kunit-test.*del*

But at the moment, it's far easier to manually comment out test cases in
test files as opposed to messing with sets of Kconfig entries to select
specific suites.
So even just doing this makes using kunit far less annoying.

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: default KUNIT_* fragments to KUNIT_ALL_TESTS

This makes it easier to enable all KUnit fragments.

Adding 'if !KUNIT_ALL_TESTS' so individual tests can not be turned off.
Therefore if KUNIT_ALL_TESTS is enabled that will hide the prompt in
menuconfig.

Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: Kconfig: enable a KUNIT_ALL_TESTS fragment

Make it easier to enable all KUnit fragments. This is useful for kernel
devs or testers, so its easy to get all KUnit tests enabled and if new
gets added they will be enabled as well. Fragments that has to be
builtin will be missed if CONFIG_KUNIT_ALL_TESTS is set as a module.

Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: add debugfs /sys/kernel/debug/kunit/<suite>/results display

add debugfs support for displaying kunit test suite results; this is
especially useful for module-loaded tests to allow disentangling of
test result display from other dmesg events. debugfs support is
provided if CONFIG_KUNIT_DEBUGFS=y.

As well as printk()ing messages, we append them to a per-test log.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: allow kunit to be loaded as a module

Making kunit itself buildable as a module allows for "always-on"
kunit configuration; specifying CONFIG_KUNIT=m means the module
is built but only used when loaded. Kunit test modules will load
kunit.ko as an implicit dependency, so simply running
"modprobe my-kunit-tests" will load the tests along with the kunit
module and run them.

Co-developed-by: Knut Omang <knut.omang@oracle.com>
Signed-off-by: Knut Omang <knut.omang@oracle.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: allow kunit tests to be loaded as a module

As tests are added to kunit, it will become less feasible to execute
all built tests together. By supporting modular tests we provide
a simple way to do selective execution on a running system; specifying

CONFIG_KUNIT=y
CONFIG_KUNIT_EXAMPLE_TEST=m

...means we can simply "insmod example-test.ko" to run the tests.

To achieve this we need to do the following:

o export the required symbols in kunit
o string-stream tests utilize non-exported symbols so for now we skip
building them when CONFIG_KUNIT_TEST=m.
o drivers/base/power/qos-test.c contains a few unexported interface
references, namely freq_qos_read_value() and freq_constraints_init().
Both of these could be potentially defined as static inline functions
in include/linux/pm_qos.h, but for now we simply avoid supporting
module build for that test suite.
o support a new way of declaring test suites. Because a module cannot
do multiple late_initcall()s, we provide a kunit_test_suites() macro
to declare multiple suites within the same module at once.
o some test module names would have been too general ("test-test"
and "example-test" for kunit tests, "inode-test" for ext4 tests);
rename these as appropriate ("kunit-test", "kunit-example-test"
and "ext4-inode-test" respectively).

Also define kunit_test_suite() via kunit_test_suites()
as callers in other trees may need the old definition.

Co-developed-by: Knut Omang <knut.omang@oracle.com>
Signed-off-by: Knut Omang <knut.omang@oracle.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Acked-by: Theodore Ts'o <tytso@mit.edu> # for ext4 bits
Acked-by: David Gow <davidgow@google.com> # For list-test
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: test: add initial tests

Add a test for string stream along with a simpler example.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

kunit: test: add KUnit test runner core

Add core facilities for defining unit tests; this provides a common way
to define test cases, functions that execute code which is under test
and determine whether the code under test behaves as expected; this also
provides a way to group together related test cases in test suites (here
we call them test_modules).

Just define test cases and how to execute them for now; setting
expectations on code will be defined later.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>