Don't hard-code object sizes

[Ivan-Velickovic]

We need to know the object sizes for the target kernel being used inside the tool

microkit/tool/microkit/src/sel4.rs

Line 433 in a7f037c

pub fn fixed_size_bits(self, config: &Config) -> Option<u64> {

.

It is vital that these are the exact same as what is in the architecture specific constants.h. These values are often highly configuration dependent which results in the tool being fragile in this area.

We should instead change the kernel build system to output a format readable by the tool (e.g JSON instead of C header) so that we don't have to hard-code all these values, or we add another step in build_sdk.py to do the same thing.

[lsf37]

json output from the kernel side would be great, then I can use that on the verification side as well.