[PATCH] ARM: zImage: add support for ARMv7-M

[Joachim Eastwood]

On 18 September 2014 19:38, Arnd Bergmann <arnd at arndb.de> wrote:
> On Thursday 18 September 2014, Joachim Eastwood wrote:
>>   ARM(          mov     pc, r4  )               @ call kernel
>> - THUMB(                bx      r4      )               @ entry point is always ARM
>> +#ifdef CONFIG_CPU_V7M
>> +               add     r4, r4, #1              @ enter in Thumb mode for ARMv7M
>> +#endif
>> + THUMB(                bx      r4      )               @ entry point is always ARM for non ARMv7M CPUs
>>
>
> I think it would be much nicer to avoid sprinkling #ifdefs here. We already
> have the ARM() and THUMB() macros to deal with the two cases we support, which
> are booting in ARM mode vs ARMv7-A with THUMB2 mode. We can probably add
> another macro like this to deal with the ARMv7-M case that does not have
> ARM mode.

Well, I guess I could make a THUMBONLY macro or something like that.
But I think that the macro would only be useful in the case you quoted
above. The other ifdefs in the patch are either for large blocks or
removing code. So I don't think it would improve the patch a great
deal.

btw, do you have better name suggestion than THUMBONLY?

regards
Joachim Eastwood