[U-Boot] ARM: Incorrect ROM protection range?

[Po-Yu Chuang]

Hi Albert,

On Thu, Feb 24, 2011 at 7:58 PM, Albert ARIBAUD <albert.aribaud at free.fr> wrote:
> Le 24/02/2011 10:39, Wolfgang Denk a écrit :
>>
>> Dear Albert ARIBAUD,
>>
>> In message<4D6611A7.5050802 at free.fr>  you wrote:
>>>
>>>>>> In the U-Boot image itself, knowing the image size could be achieved
>>>>>> in
>>>>>> ARM by using a general _end symbol that would be set after the last
>>>>>> image output section, so _end-_start would equal the image size.
>>>>>
>>>>> we have such a "_end" in u-boot.lds files.
>>>
>>> I *knew* this name did not pop up in my mind without a reason. :)
>>>
>>> Apologies for not having checked.
>>>
>>>> I guess we need a __dynsym_end in all u-boot.lds files.
>>>
>>> I'd rather go for "_end", which does not tie the solution to dynsym
>>> being the last section in the image -- imagine for some reason we move
>>> dynsym inside the image rather than at the end, end the image size will
>>> be wrong again. With _end, and a suitable comment in the LD file... this
>>> will be averted where-ever dynsym ends up.
>>>
>>> After all, the bug you uncovered was due to using the wrong symbol, a
>>> BSS related one rather than an image-related one, in the first place; so
>>> let's try and learn from past mistakes.
>>
>> I think the location of _end in the linker scripts needs to be changed
>> - so far it covers the maximum of dynsym and bss, but it should refer
>> to the end of dynsym only.
>
> Po-Yu Chuang, can you verify Wolfgang's suggestion (and make sure no other
> place depends on _end) and submit a patch? As this is a fix, a quick patch
> could still be pulled in for the upcoming release.

I think there is a problem in Wolfgang's suggestion.

Those start.S files assume that BSS section is from __bss_start to _end.
If we change _end to the end of .dynsym, then we will not clear BSS correctly.

I agree with your comment about _end is a better choice than __dynsym_end,
but if we changed _end, maybe we need __bss_end? Either way, we need to
modify all the u-boot.lds and/or start.S.

I still don't know what is the best solution.

best regards,
Po-Yu Chuang