On Sat, 2018-01-13 at 14:10 +0100, Peter Zijlstra wrote:
> On Sat, Jan 13, 2018 at 12:30:11PM +0000, David Woodhouse wrote:
> > 
> > On Sat, 2018-01-13 at 13:08 +0100, Peter Zijlstra wrote:
> > > 
> > > 
> > >         ALTERNATIVE "orq $(PTI_SWITCH_PGTABLE_MASK), \scratch_reg",
> > >                     "orq $(PTI_SWITCH_MASK), \scratch_reg", X86_FEATURE_PCID
> > > 
> > > Is not wanting to compile though; probably that whole alternative vs
> > > macro thing again :/
> > Welcome to my world. Try
> > 
> >  ALTERNATIVE __stringify(orq $(PTI_SWITCH_PGTABLE_MASK), \scratch_reg), \
> >              __stringify(orq $(PTI_SWITCH_MASK), \scratch_reg), \
> >              X86_FEATURE_PCID
> Doesn't seem to work, gets literal __stringy() crud in the .s file.

You do have to #include <linux/stringify.h> too...