Re: _ioperm support for Arm

[Phil Blundell <pb at pbcl dot net>]

On Wed, May 29, 2019 at 02:11:42PM +0200, Florian Weimer wrote:
> In the kernel, I only see a call to register_isa_ports in
> arch/arm/mach-footbridge/dc21285.c.

Right, I think that functionality was only ever supported on
DC21285 platforms.  There were more of those than just NetWinder,
but they were all StrongARM (ARMv4).

You're correct that it isn't practical for an ARMv4 machine to be 
EABI conformant because the EABI mandates interworking and ARMv4 
doesn't have BX/BLX, but last time I looked glibc did still have
all the right conditional guards in place to allow for compilation
on an ARMv4 platform.  I haven't checked recently though and it's
possible that it might have bit-rotted.  If we did want to make a
policy decision that glibc doesn't support older ARM architectures
anymore then there are probably quite a lot of #ifdefs that could
be eliminated.

All that said, I don't imagine anybody would notice if the 
ioperm() support in glibc were to go away, and in the unlikely 
event that there is some application somewhere that relies on it, 
it wouldn't be very difficult to patch ioperm() into the 
application itself.  It doesn't interact with anything else 
inside glibc.

Is there a particular reason for wanting to remove it, or is it 
just that it seems like useless cruft we could do without?

p.