[v3,0/7] x86: some assembler macro rework

Message

Jan Beulich Oct. 23, 2020, 8:34 a.m. UTC

Parts of this were discussed in the context of Andrew's CET-SS work.
Further parts simply fit the underlying picture. And a few patches
towards the end get attached here simply because of their dependency.
Patch 7 is new.

All patches except for the new ones in principle have acks / R-b-s
which would allow them to go in. However, there still the controversy
on the naming of the newly introduced header in patch 1 (which
subsequent patches then add to). There hasn't been a name suggestion
which would - imo - truly represent an improvement.

It's also still not really clear to me what - if any - changes to
make to patch 2. As said there I'd be willing to drop some of the
changes made, but not all. Prior discussion hasn't led to a clear
understanding on my part of what's wanted to be kept / dropped. It
could have looked like the entire patch was wanted to go away, but I
don't think I can agree with this. (I could see about moving this to
the end of the series, to unblock what's currently the remainder.)

1: replace __ASM_{CL,ST}AC
2: reduce CET-SS related #ifdef-ary
3: drop ASM_{CL,ST}AC
4: fold indirect_thunk_asm.h into asm-defns.h
5: guard against straight-line speculation past RET
6: limit amount of INT3 in IND_THUNK_*
7: make guarding against straight-line speculation optional

Jan