[PATCH] ARM: PJ4: allow building in Thumb-2 mode

[Olof Johansson]

On Mon, Nov 24, 2014 at 10:28 AM, Ard Biesheuvel
<ard.biesheuvel at linaro.org> wrote:
> On 24 November 2014 at 18:56, Olof Johansson <olof at lixom.net> wrote:
>> On Mon, Nov 24, 2014 at 9:17 AM, Arnd Bergmann <arnd at arndb.de> wrote:
>>> On Monday 24 November 2014 16:34:47 Ard Biesheuvel wrote:
>>>> On 24 November 2014 at 16:29, Arnd Bergmann <arnd at arndb.de> wrote:
>>>> > On Monday 24 November 2014 12:56:40 Ard Biesheuvel wrote:
>>>> >> Two files that get included when building the multi_v7_defconfig target
>>>> >> fail to build when selecting THUMB2_KERNEL for this configuration.
>>>> >>
>>>> >> In both cases, we can just build the file as ARM code, as none of its
>>>> >> symbols are exported to modules, so there are no interworking concerns.
>>>> >> In the iwmmxt.S case, add ENDPROC() declarations so the symbols are
>>>> >> annotated as functions, resulting in the linker to emit the appropriate
>>>> >> mode switches.
>>>> >>
>>>> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
>>>> >
>>>> > Ah, very nice. I tried this before, but my version didn't actually
>>>> > work, presumably because I didn't know about the ENDPROC() stuff.
>>>> >
>>>> > Have you tested this on a machine that has IWMMXT enabled?
>>>> >
>>>>
>>>> No, I don't have access to such a machine, unfortunately.
>>>
>>> Adding a few mvebu folks to Cc, maybe one of them can test your patch.
>>> It's also possible that Olof or Kevin have a PJ4 machine with iwmmxt
>>> in their boot farms.
>>
>> I have a Cubox with Dove, which does implement iWMMXt v2, based on
>> boot messages.
>>
>> I however do not have any kind of userspace programs that make use of
>> it to test with.
>>
>
> Well, I think the idea is to make sure it doesn't explode when running
> multi_v7_defconfig in thumb2 mode. That requires a machine that has
> the actual coprocessor, but as far as I can figure out from the code,
> this should not require any actual floating point use.

Well, that's easy to confirm, and I've done so now.

Not sure I'd claim that's worth a tested-by though, but whatever:

Tested-by: Olof Johansson <olof at lixom.net>

-Olof