sysdeps/unix/sysv/linux directory structure question

[Joseph Myers]

On Thu, 3 Nov 2016, Steve Ellcey wrote:

> So I have several questions.  What is the difference between
> sysdeps/unix/sysv/linux and sysdeps/unix/sysv/linux/generic and why
> are some files in one vs. the other vs. both?   Is generic only for 64-

generic is for newer architectures using the generic syscall ABI, where 
syscalls that can be implemented in terms of newer syscalls are generally 
omitted (so only statat syscalls not the older stat ones, for example), 
and where structures are the same between different architectures as far 
as possible (whereas various structures on older architectures commonly 
tried to follow the layout used by some proprietary Unix on that 
architecture).

> bit kernels?  Is that why it has a wordsize-32 subdirectory?  Are

The generic syscall ABI only has 64-bit versions of various structures, 
with 32-bit architectures expected to do EOVERFLOW handling in userspace.

-- 
Joseph S. Myers
joseph@codesourcery.com