[FEATURE] Add fuzzing endpoints for math functions

[cujomalainey]

Is your feature request related to a problem? Please describe.
We have a lot of math functions with precise lookups. If not implemented correctly they could in theory be overflowed resulting in either broken audio or bad memory accesses.

Describe the solution you'd like
Fuzz endpoints for the math functions. Fuzzing time should be quite short since there is no state.

Describe alternatives you've considered
N/A

Additional context
Recommended by @lgirdwood

[cujomalainey]

@afq984 I set you as the placeholder owner, if you have time to do this great, otherwise I might bump it to Eddy once I add him to the org

[lgirdwood]

@singalsu @ShriramShastry fyi.
@cujomalainey I guess we can do this via the cmocka or host based build ? If this works well we could extend to other APIs that take host data (at the layers down from the IPC like the components set / get config()).

[cujomalainey]

We really just need to copy the ipc fuzz endpoint, drop all the calls to initialize SOF since the math should not need it. Drop the initialize function. Register the new endpoint and setup for short fuzzing (like 5-10s should probably be good). And we are good.

Thinking about it, it might be better to simply sample the domain of the functions and run it with something like valgrind or the sanitizers as part of the cmocka test like Liam suggested for the math.

The set/get APIs will get hit once we add the components, but significantly less frequently. So it might is worth doing a fuzzing endpoint in which we call those APIs on the components directly to make sure we get good coverage.

[lgirdwood]

Fwiw, all the mocka and testbench can all run with valgrind now (and testbench pulls in more of pipeline logic too).

[cujomalainey]

that looks good, I think if we add sanitizers we should be good, specifically ubsan and maybe address, memory i think should not matter as we are not doing allocs in math

[cujomalainey]

The more I think about this, we could just run the range of values with ubsan and that should cover this as part of something like a unit test

[lgirdwood]

@singalsu @andrula-song @ShriramShastry I know we have UTs for testing maths APIs, can we expand these a little and use ubsan ?
https://developers.redhat.com/blog/2014/10/16/gcc-undefined-behavior-sanitizer-ubsan

[singalsu]

@singalsu @andrula-song @ShriramShastry I know we have UTs for testing maths APIs, can we expand these a little and use ubsan ? https://developers.redhat.com/blog/2014/10/16/gcc-undefined-behavior-sanitizer-ubsan

I didn't know such exist, seems like it's good to add to UT x86 build at least, probably also to testbench since valgrind is not detecting all of that.