On Tue, 2022-02-08 at 14:27 +0100, Pierre Morel wrote: > We check the PTF instruction. You could test some very basic things as well: - you get a privileged pgm int in problem state, - reserved bits in first operand cause specification pgm int, - reserved FC values result in a specification pgm int, - second operand is ignored. > > - We do not expect to support vertical polarization. > > - We do not expect the Modified Topology Change Report to be [...] Forgive me if I'm missing something, but why _Modified_ Topology Change Report? > diff --git a/s390x/topology.c b/s390x/topology.c > new file mode 100644 > index 00000000..a1f9ce51 > --- /dev/null > +++ b/s390x/topology.c [...] > +static int ptf(unsigned long fc, unsigned long *rc) > +{ > + int cc; > + > + asm volatile( > + " .insn rre,0xb9a20000,%1,0\n" > + " ipm %0\n" > + " srl %0,28\n" > + : "=d" (cc), "+d" (fc) > + : "d" (fc) Why list fc here again?