v7-M: Fixing XIP when the kernel is in ROM

[Stefan Agner]

On 2015-10-27 13:25, Maxime Coquelin wrote:
> 2015-10-27 17:03 GMT+01:00 Maxime Coquelin <maxime.coquelin at st.com>:
>> Hi Ezequiel,
>>
>> On 10/27/2015 04:35 PM, Ezequiel Garcia wrote:
>>>>
>>>> >>>The temporary stack is allocated in the .text.init section
>>>> >>>and so this doesn't work when the kernel is executing from ROM.
>>>
>>> >>
>>> >>If sp isn't used, how does it break you setup?
>>
>> STM32 machine works fine with XIP from internal flash memory, so as Uwe, I'm
>> surprised it solves your problem.
>>
>> I will have a try with your patch later today.
> 
> Just tested, and confirm it works with (and without) your patch in XIP on STM32.

It probably depends what exactly happens when the CPU core tries to use
the stack. I mean, the CPU core will issue a write to the flash, and how
that behaves is probably implementation specific. However, I would
expect that it should lead to some kind of fault... Do we have fault
handlers at that time?

Anyway, I guess Ezequiel's fix is the right thing to do...

--
Stefan