[PATCH 1/1] ARM: thumb: Have the machine name indicate operation in thumb mode.

[linux@arm.linux.org.uk (Russell King - ARM Linux)]

On Wed, May 25, 2011 at 03:08:05PM -0700, Vadim Bendebury (??) wrote:
> On Wed, May 18, 2011 at 3:57 PM, Russell King - ARM Linux <
> linux at arm.linux.org.uk> wrote:
> > In which case I think we'll have to talk to kbuild people to get
> > mkcompile_h modified.  Also maybe asking what other architectures
> > do for this kind of problem may be a good idea - especially before
> > we start abusing and hacking stuff like the hardware name.
> 
> So, what would be an equivalent in other architectures to ask about - it
> seems that the ability to run in Thumb/ARM mode is fairly unique for ARM.

What about 32-bit vs 64-bit x86 ?

> Consulting /boot/config file is not reliable: in my own setup I can netboot
> either thumb or ARM kernel without changing the root file system contents. I
> agree though that changing the hardware name is not the best way to do this
> either.
> 
> I could look into adding 'thumb' to any element of the uname output, or as a
> watered down version - just add a line to dmesg output?

The thing that I worry about is that userspace will start using this
information inappropriately.  Whether the kernel is built as T2 or ARM
is really only a matter for the kernel itself (and people debugging the
kernel), rather than random userspace programs.

Maybe a way forward would be to produce a patch for mkcompile_h, post it
to here, kbuild people and LKML and see what response is forthcoming.