[CentOS] sysconf and _SC_LEVEL1_DCACHE_LINESIZE returns 0?

Hi Everyone,

I'm working on GCC112, which is POWER System S822 (Power8) machine
running CentOS 7 machine (https://gcc.gnu.org/wiki/CompileFarm):

    $ cat /etc/centos-release
    CentOS Linux release 7.3.1611 (AltArch)

I'm trying to determine L1 data cache size. When the following code
runs it returns 0. The man pages state -1 is an error, so I think its
claiming to succeed.

    cacheLineSize = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);

GCC119, which is also a S822 Power8 running AIX, returns 128.

Does anyone know what I might be doing wrong under Cent? Or maybe, how
can I retrieve the L1 data cache line size?

Thanks in advance.