selftests: livepatch: Test livepatching a heavily called syscall

The test proves that a syscall can be livepatched. It is interesting
because syscalls are called a tricky way. Also the process gets
livepatched either when sleeping in the userspace or when entering
or leaving the kernel space.

The livepatch is a bit tricky:
1. The syscall function name is architecture specific. Also
ARCH_HAS_SYSCALL_WRAPPER must be taken in account.

2. The syscall must stay working the same way for other processes
on the system. It is solved by decrementing a counter only
for PIDs of the test processes. It means that the test processes
has to call the livepatched syscall at least once.

The test creates one userspace process per online cpu. The processes
are calling getpid in a busy loop. The intention is to create random
locations when the livepatch gets enabled. Nothing is guarantted.
The magic is in the randomness.

Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

livepatch: Move tests from lib/livepatch to selftests/livepatch

The modules are being moved from lib/livepatch to
tools/testing/selftests/livepatch/test_modules.

This code moving will allow writing more complex tests, like for example an
userspace C code that will call a livepatched kernel function.

The modules are now built as out-of-tree
modules, but being part of the kernel source means they will be maintained.

Another advantage of the code moving is to be able to easily change,
debug and rebuild the tests by running make on the selftests/livepatch
directory, which is not currently possible since the modules on
lib/livepatch are build and installed using the "modules" target.

The current approach also keeps the ability to execute the tests manually
by executing the scripts inside selftests/livepatch directory, as it's
currently supported. If the modules are modified, they needed to be
rebuilt before running the scripts though.

The modules are built before running the selftests when using the
kselftest invocations:

make kselftest TARGETS=livepatch
or
make -C tools/testing/selftests/livepatch run_tests

Having the modules being built as out-of-modules requires changing the
currently used 'modprobe' by 'insmod' and adapt the test scripts that
check for the kernel message buffer.

Now it is possible to only compile the modules by running:

make -C tools/testing/selftests/livepatch/

This way the test modules and other test program can be built in order
to be packaged if so desired.

As there aren't any modules being built on lib/livepatch, remove the
TEST_LIVEPATCH Kconfig and it's references.

Note: "make gen_tar" packages the pre-built binaries into the tarball.
It means that it will store the test modules pre-built for
the kernel running on the build host.

Note that these modules need not binary compatible with
the kernel built from the same sources. But the same
is true for other packaged selftest binaries.

The entire kernel sources are needed for rebuilding
the selftests on another system.

Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/livepatch: add sysfs test

Add a test for livepatch sysfs entries.

Signed-off-by: Song Liu <song@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220902205208.3117798-3-song@kernel.org

selftests: Install settings files to fix TIMEOUT failures

Commit 852c8cbf34d3 ("selftests/kselftest/runner.sh: Add 45 second
timeout per test") added a 45 second timeout for tests, and also added
a way for tests to customise the timeout via a settings file.

For example the ftrace tests take multiple minutes to run, so they
were given longer in commit b43e78f65b1d ("tracing/selftests: Turn off
timeout setting").

This works when the tests are run from the source tree. However if the
tests are installed with "make -C tools/testing/selftests install",
the settings files are not copied into the install directory. When the
tests are then run from the install directory the longer timeouts are
not applied and the tests timeout incorrectly.

So add the settings files to TEST_FILES of the appropriate Makefiles
to cause the settings files to be installed using the existing install
logic.

Fixes: 852c8cbf34d3 ("selftests/kselftest/runner.sh: Add 45 second timeout per test")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/livepatch: Test interaction with ftrace_enabled

Since livepatching depends upon ftrace handlers to implement "patched"
code functionality, verify that the ftrace_enabled sysctl value
interacts with livepatch registration as expected. At the same time,
ensure that ftrace_enabled is set and part of the test environment
configuration that is saved and restored when running the selftests.

Link: http://lkml.kernel.org/r/20191016113316.13415-4-mbenes@suse.cz

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

livepatch: Selftests of the API for tracking system state changes

Four selftests for the new API.

Link: http://lkml.kernel.org/r/20191030154313.13263-6-pmladek@suse.com
To: Jiri Kosina <jikos@kernel.org>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Cc: Nicolai Stange <nstange@suse.de>
Cc: live-patching@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>

selftests/livepatch: Add functions.sh to TEST_PROGS_EXTENDED

Add functions.sh to TEST_PROGS_EXTENDED so that it is installed along
with the rest of the selftests and they can be run.

Originally-by: Shuah Khan <shuah@kernel.org>
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>

selftests/livepatch: use TEST_PROGS for test scripts

Adrian reports that 'make -C tools clean' results in removal of the
livepatch selftest shell scripts.

As per the selftest lib.mk file, TEST_PROGS are for test shell scripts,
not TEST_GEN_PROGS. Adjust the livepatch selftest Makefile accordingly.

Reported-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Tested-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>

selftests/livepatch: introduce tests

Add a few livepatch modules and simple target modules that the included
regression suite can run tests against:

- basic livepatching (multiple patches, atomic replace)
- pre/post (un)patch callbacks
- shadow variable API

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Tested-by: Miroslav Benes <mbenes@suse.cz>
Tested-by: Alice Ferrazzi <alice.ferrazzi@gmail.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>