[bionic] LP#1758856 -- retpoline hinting support

[Andy Whitcroft]

On Tue, Mar 27, 2018 at 05:23:52PM -0500, Seth Forshee wrote:
> On Mon, Mar 26, 2018 at 04:07:45PM +0100, Andy Whitcroft wrote:
> > We have been having horrible problems with the retpoline information as
> > recorded in the ABI changing on every update.  The below pull-request
> > brings in some new support utilising the upstream retpoline annotations.
> > As well as bringing in some new annotations where needed.
> > 
> > This should in time bring us to the situation where the retpoline
> > information for every branch is empty.  Where unannotated entries remain
> > they are in review and will be coverered off in later updates.  These
> > are not regressions.
> > 
> > Proposing for bionic.
> 
> I tested this with bionic, for non-amd64 arches I'm getting an error
> packaging the headers:
> 
> # We do not need the retpoline information.
> find /tmp/kernel-sforshee-dc36af1-llEk/build/debian/linux-headers-4.15.0-14-generic/usr/src/linux-headers-4.15.0-14-generic -name \*.o.ur-\* | xargs rm
> rm: missing operand
> 
> Surprisingly I got that for i386 too, which I would have expected to
> have some of these files.

You only get it is something 'prepare' creates has .o files, which is
only objtool which is only amd64.  The error should be benign, but
changing that to xargs rm -f would be appropriate there.

-apw