[PATCH v2 0/6] x86: Add stright-line-speculation mitigations

[Peter Zijlstra]

Respin and split of the SLS patch.

Since the old patch hit a snag, I've split up the patch as per popular demand.

New this time are patches 1 and 5 and some minor edits to the last patch, the
rest is mostly identical.

Patch 1 removes a 32bit (abuse) of the RET macro; which got exposed by the
build robot due to a change in the last patch (defining RET even for
!CONFIG_SLS). It would've been possible to revert to the old method of relying
on AS being case insensitive and RET being a valid instruction etc.. but I
figured that code was convoluted enough to warrant cleaning up anyway.

Patch 5 is what made Boris' machine go BUG when he tried to use the SLS patch.

Combined it seems to boot and build a kernel for me, so it must be perfect this
time (fingers crossed).