CONFIG_MARCH_Z990 is not available for thedefaultarchitecture x86.
Result is shown for architecture s390

IBM zSeries model z890 and z990

configname: CONFIG_MARCH_Z990

Processor type
└─>IBM zSeries model z890 and z990
In linux kernel since version 2.6.12  
Select this to enable optimizations for model z890/z990 (2084 and
2086 series). The kernel will be slightly faster but will not work
on older machines.


depends
CONFIG_cc-option