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

Ard Biesheuvel ard.biesheuvel at linaro.org
Mon Nov 24 11:49:36 PST 2014


On 24 November 2014 at 20:01, Gregory CLEMENT
<gregory.clement at free-electrons.com> wrote:
> On 24/11/2014 18:48, Ard Biesheuvel wrote:
>> On 24 November 2014 at 18:36, Gregory CLEMENT
>> <gregory.clement at free-electrons.com> wrote:
>>> Hi Arnd,
>>>
>>> On 24/11/2014 18:17, Arnd Bergmann 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.
>>>
>>> Actually even it is a feature of the PJ4 machine non of the mvebu machines
>>> currently use it. I only see this configuration enabled for the pxa family.
>>> So I think you would have more feedback with the pxa maintainers/owners.
>>>
>>
>> Are you saying PJ4 should be dropped from 'default' here?
>
> Not at all. I didn't find it in the configuration file, but I didn't realized
> it was because of this "default y".
>
> Sorry for the noise.
>

Ah, ok.

In that case, could you perhaps also test this patch on a PJ4 machine
with multi_v7_defconfig but with CONFIG_THUMB2_KERNEL enabled?
Olof has already done so successfully, but just to be sure.

Thanks,
Ard.



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