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

Ard Biesheuvel ard.biesheuvel at linaro.org
Mon Nov 24 10:28:23 PST 2014

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.


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