[PATCH v2 00/11] Fix up SRSO stuff

[Peter Zijlstra]

Hi!

Second version of the SRSO fixes/cleanup.

I've redone some, reorderd most and left out the interface bits entirely for
now. Although I do strongly feel the extra interface is superfluous (and ugly).

This is based on top of current tip/x86/urgent 833fd800bf56.

The one open techinical issue I have with the mitigation is the alignment of
the RET inside srso_safe_ret(). The details given for retbleed stated that RET
should be on a 64byte boundary, which is not the case here.

I'll go prod at bringing the rest of the patches forward after I stare at some
other email.