typo

How widely used is bcopy_data in CHERI? Is it reasonable to move those to memmove_data (possibly moving to memmove first in FreeBSD)? It seems slightly unfortunate to make a new version of a legacy/obsolete interface.

None of these are widely used. memmove_data is currently completely unused except to implement bcopy_data. I actually think most (or even all) could be memcpy_data (I don't think any of these overlap).

The one slightly perverse argument for bcopy_data is that it's safely outside the reserved mem* namespace.

I'll make the s/bcopy/memcpy changes and do some consolidation along the way.

where is "pointer provenance" defined?

Now linked to a discussion in arch(7).

Do you not get a warning about keeptags being unused in non-CHERI kernels?

Given our explicit decision of making this the non-default case, do we want to make this read a bit more in an active sense -- something along the lines of "discards" rather than "does not preserve"?

"Discards pointer provenance" is not quite right though. In a CHERI sense we could maybe use "discards capability validity." Anyway, a suggestion if you can find a good way to express this, otherwise we can leave it until CHERI-specific content starts getting added.

Same comment as above

I've added some more active CHERI-specific content. In the non-CHERI case it's probably best to be somewhat passive here since it's literally a no-op today.

I've added a __maybe_unused.

Not part of your change but this is a stray .Pp

Which pointer?
I suspect the pointers contained in the copied object?