Re: [PATCH v5 0/4] ARM: ep93xx: ts72xx: Add support for BK3 board

From: Arnd Bergmann
Date: Mon Dec 18 2017 - 06:56:01 EST

On Sun, Dec 17, 2017 at 10:28 PM, Lukasz Majewski <lukma@xxxxxxx> wrote:
> Hi Arnd,
>> On Sun, Dec 17, 2017 at 8:41 PM, Lukasz Majewski <lukma@xxxxxxx>
>> wrote:
>> >> >> We also need to think about upholding support in GCC for
>> >> >> ARMv4(t) for the foreseeable future if there is a big web of
>> >> >> random deeply embedded systems out there that will need
>> >> >> updates.
>> >> >
>> >> > But we should definitely preserve at least what we have.
>> >>
>> >> Plain ARMv4 (and earlier) support in gcc is already marked
>> >> 'deprecated' and will likely be gone in gcc-8 (it's still there as
>> >> of last week). ARMv4T is going to be around for a while, and you
>> >> can even keep building for ARMv4 using "-march=armv4t -marm" when
>> >> linking with 'ld --fix-v4bx'.
>> >
>> > I think that we shall start complaining on the gcc-devel mailing
>> > list now.
>> >
>> > I would be hard to wake up in 2 years time and realise that we don't
>> > have a modern compiler.
>> What distro or build system are you using?
> I'm using OE with the "include conf/machine/include/"
> GCC 7.2 is working

Ah wait, this is still for ep93xx, which is always at least armv4t, right?
So it won't have a problem with the armv4 deprecation anyway, even
the older ep72xx/73xx were ARM720T based and don't have a problem.
I'm not entirely sure about their clps711x predecessors, which were some
earlier arm7 variant, but Linux doesn't support them any more anyway,
and the ARM710T would already be fine without --fix-v4bx.

>> It would also be helpful
>> to test whether the -march=armv4t/--fix-v4bx workaround produces
>> working binaries for you, in that case you could report to the gcc
>> developers that the removal of armv4 can continue but that
>> the --fix-v4bx option in ld needs to stay around.
> I may ask this issue on OE/Yocto mailing list as well....

To clarify, the only affected platforms are those based on either
DEC/Intel StrongARM or Faraday FA526, i.e. EBSA-110,
FootBridge, RPC, SA1100, Moxart and Gemini.