PERF_REG_S390_R0
if (idx >= PERF_REG_S390_R0 && idx <= PERF_REG_S390_R15)
[PERF_REG_S390_R0] = 0,
return unw_regnum - UNW_S390X_R0 + PERF_REG_S390_R0;
case PERF_REG_S390_R0: