Re: [PATCH 1/7] [RFC] ARM: remove Intel iop33x and iop13xx support

[Aaro Koskinen <aaro.koskinen@xxxxxx>]

Hi,

On Fri, Aug 16, 2019 at 04:58:33PM +0100, Russell King - ARM Linux admin wrote:
> On Fri, Aug 16, 2019 at 06:42:49PM +0300, Aaro Koskinen wrote:
> > On Wed, Aug 14, 2019 at 10:36:01AM +0200, Linus Walleij wrote:
> > > On Mon, Aug 12, 2019 at 11:45 AM Martin Michlmayr <tbm@xxxxxxxxxx> wrote:
> > > > As Arnd points out, Debian used to have support for various iop32x
> > > > devices.  While Debian hasn't supported iop32x in a number of years,
> > > > these devices are still usable and in use (RMK being a prime example).
> > > 
> > > I suppose it could be a good idea to add support for iop32x to
> > > OpenWrt and/or OpenEmbedded, both of which support some
> > > pretty constrained systems.
> > 
> > This platform is not really too constrained... E.g. on N2100 you have
> > 512 MB RAM, SATA disks and gigabit ethernet. Not that different from
> > mvebu that Debian currently (?) supports. Maybe with multiplatform they
> > could support iop32x again.
> 
> Probably not.  The kernel has a dividing line between ARMv5 and ARMv6
> where it's not possible to multiplatform across that boundary, so
> you're already needing separate kernel images there.
> 
> Secondly, armhf distros won't be compatible with ARMv5, and to make
> them compatible will make performance on armhf suffer - you have to
> stop using barriers, exclusive load/store and a few other things.
> You have to rely on the kuser page exported by the kernel (which is
> now optional as it's deemed to be a security issue for ROP attacks)
> for some things that such a userspace requires - such as NPTL support.
> 
> Effectively, ARMv5 is an entirely separate userspace distro from armhf.

I thought they still had armel for ARMv5 and mvebu (kirkwood).

A.