C64-Secure ABI demo.

[jacobbramley]

This demo illustrates a few calling-convention options for weak (but potentially fast) compartmentalisation across function calls.

[ltratt]

@jacobbramley This looks good, and useful -- thanks!

@0152la Is there an easy way of only building this example in CI on Morello? I must admit that I've forgotten how to navigate the infrastructure for this repo...

[jacobbramley]

@0152la Is there an easy way of only building this example in CI on Morello? I must admit that I've forgotten how to navigate the infrastructure for this repo...

I think I could add it to .buildbot.sh fairly easily. I'll do that whilst I fix the other issues.

[ltratt]

@jacobbramley I remember there's some fiddling because we and try and support multiple platforms. Good luck!

[0152la]

@0152la Is there an easy way of only building this example in CI on Morello? I must admit that I've forgotten how to navigate the infrastructure for this repo...

I think I could add it to .buildbot.sh fairly easily. I'll do that whilst I fix the other issues.

I think the process is:
(a) to build, it'll need to be added to .buildbot.sh. Currently we seem to build both riscv and morello together [1], so you'll probably need another block that'll be (pseudocode) push; make morello-purecap clean; make morello-purecap all; pop.
(b) to run, add it somewhere in the appropriate block in run_tests.sh [2]. I think since it's built only for morello, it'll only be run for morello, but unsure here.

However, since the infrastructure is a bit flimsy I'd think, perhaps as long as it builds it's fine, or even could preclude adding it. I think there's some stuff that's not been ran in CI, and we should probably add everything once (if) we redo the CI.

[1] https://github.com/capablevms/cheri-examples/blob/master/.buildbot.sh#L16-L25
[2] https://github.com/capablevms/cheri-examples/blob/master/tests/run_tests.sh#L64

[probablytom]

Thanks for the patience with this review being so late. Mostly small notes on comments & explanatory text! Great example.

[ltratt]

@probablytom Can you mark your comments as resolved (if they're resolved) or comment further? I have the impression this is more-or-less mergeable now, but I'm not 100% sure!

[jacobbramley]

Ok, I pushed a change that replaces TODO with NB in a few places. I think that's all the outstanding comments.

I had already integrated this with .buildbot.sh but it's not added to runtests.sh because it's purely interactive, and there's no suitable mode for scripted use. It could be scripted, but a failure is likely to manifest as a timeout, so it makes more sense to have a special batch mode, but then that's more code, etc. Let me know if you still think it's worthwhile.

[ltratt]

I think we should get this in now, and if we can polish it further in the future, even better!

Please squash.

[jacobbramley]

Squashed!

[0152la]

We don't have CI set up on this repo, so merge queues won't work.

Ignore that.