selftests/user_events: Test persist flag cases

Now that we have exposed USER_EVENT_REG_PERSIST events can persist both
via the ABI and in the /sys/kernel/tracing/dynamic_events file.

Ensure both the ABI and DYN cases work by calling both during the parse
tests. Add new flags test that ensures only USER_EVENT_REG_PERSIST is
honored and any other flag is invalid.

Link: https://lkml.kernel.org/r/20230912180704.1284-3-beaub@linux.microsoft.com

Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

selftests/user_events: Fix to unmount tracefs when test created mount

Fix to unmount tracefs if the self-test mounted it to allow testing.
If tracefs was already mounted, this does nothing.

Suggested-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/all/29fce076-746c-4650-8358-b4e0fa215cf7@sirena.org.uk/
Fixes: a06023a8f78d ("selftests/user_events: Fix failures when user_events is not installed")

Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/user_events: Fix failures when user_events is not installed

When user_events is not installed the self tests currently fail. Now
that these self tests run by default we need to ensure they don't fail
when user_events was not enabled for the kernel being tested.

Add common methods to detect if tracefs and user_events is enabled. If
either is not enabled skip the test. If tracefs is enabled, but is not
mounted, mount tracefs and fail if there were any errors. Fail if not
run as root.

Fixes: 68b4d2d58389 ("selftests/user_events: Reenable build")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Link: https://lore.kernel.org/all/CA+G9fYuugZ0OMeS6HvpSS4nuf_A3s455ecipGBvER0LJHojKZg@mail.gmail.com/

Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/user_events: Test struct size match cases

The self tests for user_events currently does not ensure that the edge
case for struct types work properly with size differences.

Add cases for mis-matching struct names and sizes to ensure they work
properly.

Link: https://lkml.kernel.org/r/20230629235049.581-3-beaub@linux.microsoft.com

Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

selftests/user_events: Adapt dyn_test to non-persist events

Now that user_events does not honor persist events the dynamic_events
file cannot be easily used to test parsing and matching cases.

Update dyn_test to use the direct ABI file instead of dynamic_events so
that we still have testing coverage until persist events and
dynamic_events file integration has been decided.

Link: https://lkml.kernel.org/r/20230614163336.5797-6-beaub@linux.microsoft.com

Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

selftests: use canonical ftrace path

The canonical location for the tracefs filesystem is at /sys/kernel/tracing.

But, from Documentation/trace/ftrace.rst:

Before 4.1, all ftrace tracing control files were within the debugfs
file system, which is typically located at /sys/kernel/debug/tracing.
For backward compatibility, when mounting the debugfs file system,
the tracefs file system will be automatically mounted at:

/sys/kernel/debug/tracing

A few spots in tools/testing/selftests still refer to this older debugfs
path, so let's update them to avoid confusion.

Link: https://lkml.kernel.org/r/20230313211746.1541525-1-zwisler@kernel.org

Cc: "Tobin C. Harding" <me@tobin.cc>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tycho Andersen <tycho@tycho.pizza>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Ross Zwisler <zwisler@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

user_events: Add self-test for dynamic_events integration

Tests matching deletes, creation of basic and complex types. Ensures
common patterns work correctly when interacting with dynamic_events
file.

Link: https://lkml.kernel.org/r/20220118204326.2169-9-beaub@linux.microsoft.com

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>