[U-Boot] [PATCH 4/4] ARM: tegra: increase CONFIG_SYS_TEXT_BASE

[Stephen Warren]

On 10/17/2012 06:05 PM, Simon Glass wrote:
> Hi Stephen.
> 
> On Tue, Oct 16, 2012 at 3:43 PM, Stephen Warren <swarren at wwwdotorg.org> wrote:
>> On 10/16/2012 04:09 PM, Lucas Stach wrote:
>>> Am Dienstag, den 16.10.2012, 15:50 -0600 schrieb Stephen Warren:
>>>> From: Stephen Warren <swarren at nvidia.com>
>>>>
>>>> The SPL has grown. Increase CONFIG_SYS_TEXT_BASE so SPL's BSS does not
>>>> overlap the main U-Boot.
>>>
>>> Is there any specific reason why the SPL is now bigger than before? Or
>>> is this just because of the general U-Boot rework (like serial multi
>>> anywhere)? And by how much has it grown? This is really more out of
>>> curiosity rather than any real objection.
>>
>> Looking at this more, I built commit cca6076 "tegra20: Remove armv4t
>> build flags" which was the last patch in the series that enabled SPL on
>> Tegra, and it overflows even there:
>>
>> Configuring for ventana board...
>>    text    data     bss     dec     hex filename
>>  226085    4384  274228  504697   7b379 ./u-boot
>>   13857     153    4516   18526    485e ./spl/u-boot-spl
>>
>> u-boot/master currently has:
>>
>> Configuring for ventana board...
>>    text    data     bss     dec     hex filename
>>  233579    4432  274368  512379   7d17b ./u-boot
>>   14382     201    4520   19103    4a9f ./spl/u-boot-spl
>>
>> So, there is slight growth, but mainly I think we've just been getting
>> lucky.
>>
>> Also, the overflow might possibly only have been exposed by the recent
>> serial rework; when I found the problem the serial rework caused on
>> Tegra, Allen mentioned that the missing BSS clearing hadn't been a
>> problem before since no global variables were used, but the serial
>> rework caused some to be.
> 
> To ask the opposite question, is it worth increasing by a whole 16KB
> so that the base address of U-Boot is a more aligned number?

That would bloat the binary by about 12KB more than it needs to be. I
don't believe there's any particular need for the main U-Boot to be
built for any particular address, and we can just continue to bump up
this value as/when the SPL grows.