On Tue, 20 Jan 2015, Joshua Kinard wrote:
> > Userspace C code doesn't need this as it has its own standard ways of
> > determining endianness.
> >
> > If you need to know as a user you can do:
> >
> > readelf -h /bin/sh | grep Data | cut -d, -f2
I tend to use `file /sbin/init' if I need to check it for some reason --
less typing. ;)
> This would only tell you the endianness of the userland binary, not of the
> kernel. While they should be one and the same (otherwise, you're not going to
> get very far anyways), they are, technically, distinctly different properties.
Well, several MIPS processors can reverse the user-mode endianness via
the CP0.Status.RE bit; though as you may be aware it has never been
implemented for Linux. Otherwise it would obviously have to be a
per-process property (and execve(2) could flip it back).
What you may find more interesting, we actually used to include this
information in /proc/cpuinfo, long ago, and I believe it was removed for
the very reason of the existence of this reverse-endianness feature.
Which I find sort of weak an argument given that we don't support this
stuff anyway, but given the simple ways to extract this information from
elsewhere (/proc/config.gz is another candidate place) I have doubts if
having it in /proc/cpuinfo adds any value too. Not that I'd object it
strongly either though.
See:
commit 874124ebb6309433a2e1acf1deb95baa1c34db0b
Author: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Date: Sun Dec 2 11:34:32 2001 +0000
Merge with Linux 2.4.15.
-- which actually makes me wonder what happened here as Linus's 2.4.15
change does not include any of this stuff. Only 2.4.19 does, 8 months
later -- a CVS to GIT conversion problem?
Maciej
