[U-Boot] [PATCH] arm: Disable the strict alignment of data on armv7

Michal Simek michal.simek at xilinx.com
Fri Mar 9 06:59:03 UTC 2018


Hi Wolfgang,

On 8.3.2018 23:52, Wolfgang Denk wrote:
> Dear Michal,
> 
> In message <029f7f8f6d89cc77c92e04223a7402376e050f56.1520433579.git.michal.simek at xilinx.com> you wrote:
>> From: Nitin Jain <nitin.jain at xilinx.com>
>>
>> This patch is used for disable the strict alignment of data
>> to avoid the memory alignment issues.
> 
> Can you please add some comments what the consequences of this
> change are?  I guess there are advantages, but I also guess these
> come at a price?

That's something what I am expecting from this discussion if there are
any corner cases which we are not aware of.

We found this setting based on randomized testing where simply non
aligned access for memory read was causing exception.
The same tests were running fine on arm64 where non aligned accesses are
permitted.
It is hard to compare performance impact on u-boot but from
functionality point of view we are not able to see difference.
If there is any performance impact that it is quite low.

Thanks,
Michal


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