uclibc-ng/libc/sysdeps/linux/README

This directory level abstracts out the Linux Operating System dependent
features of uClibc for suported Linux architectures/CPUs.  If you wanted to
port uClibc to some new Linux architecture (arm, mips, etc), this is the place
to add that support.

All the common stuff that is not at all dependent on a particular Linux architecture
goes in the 'common' directory.