Re: [PATCH] prctl: implement PR_GET_ENDIAN for all architectures

On Wed, 1 Feb 2017 20:47:06 +0100 Helge Deller [off-list ref] wrote:

Hi Andrew,

On 01.02.2017 01:26, Andrew Morton wrote:

quoted

On Sat, 28 Jan 2017 12:13:10 +0100 Helge Deller [off-list ref] wrote:

quoted

The prctl(PR_GET_ENDIAN) syscall was added to Kernel 2.6.18, but
implemented for PowerPC only.
This trivial patch adds support for this syscall for all other architectures.

Seems reasonable.  I guess.

Heck, I did forgot but I submitted a similar patch 8 years ago:
http://www.serverphorums.com/read.php?12,51902

quoted

Why is this needed?

It's not actually needed beside the trivial reason of providing an interface
not just for one single architecture.

After reading the discussion from 2009 again, I'm fine if 
you would simply drop the patch. The decision up to you.

Can't decide.  I guess that moving it into the kernel will, over time,
eliminate some irritating ifdefs from userspace code.

The implementation itself is a bit half-assed.  The put_user() in
arch/powerpc/kernel/process.c:get_endian() should be moved into
kernel/sys.c.  So the arch code only does the "what endianness am I"
function and common code copies that out to userspace.