[U-Boot] [PATCH v3 1/5] sunxi: a64: Enable FIT Signature

[Andre Przywara <andre.przywara@arm.com>]

Hi,

On 15/12/17 15:05, Jagan Teki wrote:
> On Fri, Dec 15, 2017 at 8:06 PM, Andre Przywara <andre.przywara@arm.com> wrote:
>> Hi,
>>
>> On 15/12/17 13:41, Maxime Ripard wrote:
>>> On Thu, Dec 14, 2017 at 02:03:12PM +0530, Jagan Teki wrote:
>>>> On Wed, Dec 13, 2017 at 9:09 PM, Maxime Ripard
>>>> <maxime.ripard@free-electrons.com> wrote:
>>>>> On Wed, Dec 13, 2017 at 11:33:02AM +0530, Jagan Teki wrote:
>>>>>> From: Jagan Teki <jagannadh.teki@gmail.com>
>>>>>>
>>>>>> Enable FIT_SIGNATURE for sunxi a64.
>>>>>>
>>>>>> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
>>>>>> ---
>>>>>> Changes for v3:
>>>>>> - Move imply outside block
>>>>>> Changes for v2:
>>>>>> - Use imply instead of select
>>>>>>
>>>>>>  arch/arm/mach-sunxi/Kconfig | 1 +
>>>>>>  1 file changed, 1 insertion(+)
>>>>>>
>>>>>> diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig
>>>>>> index 1fededd..05e2d47 100644
>>>>>> --- a/arch/arm/mach-sunxi/Kconfig
>>>>>> +++ b/arch/arm/mach-sunxi/Kconfig
>>>>>> @@ -179,6 +179,7 @@ config MACH_SUN50I
>>>>>>       select SUNXI_DRAM_DW_32BIT
>>>>>>       select FIT
>>>>>>       select SPL_LOAD_FIT
>>>>>> +     imply FIT_SIGNATURE
>>>>>
>>>>> I'm really not sure we should force it by default. How much code size
>>>>> is it adding?
>>>>
>>>> Why we need to consider u-boot size? (because it may cross the loader2 size?)
>>>> Here is the delta of u-boot elf
>>>
>>> The same reason than anything else on our arm64 builds lately: we have
>>> a u-boot binary too big for the size compared to our environment offset.
>>
>> I agree, and aside from that I don't see how this is useful:
>> - We don't *need* this for Allwinner boards.
> 
> why? can you elaborate?

I guess *you* have to present why we would need it. Fact is it happily
runs without it, it's just some optional feature. Most users which rely
on the defconfig don't have a need for this. If someone wants to use it,
enabling this is the config is their least problem.

>> - It is not usable without some more setup (which that other doc patch
>> describes).
> 
> doc patch is rejected since we have redundant docs on the same topic.

I know ;-)
As mentioned above, for this feature to be useful you have to go through
quite some other steps, so there is no reason for it to be enabled by
default.

>> - As Maxime mentioned, this is not very helpful on it's own, due to it
>> inherent vulnerability without a protected SPL as well.
>> - No other boards seems to set FIT_SIGNATURE.
> 
> I'm mentioning this again, please check the other platforms as well
> this is verified-boot not secure-boot, other platforms will do use
> same.

Sure, but none of them sets this unconditionally in their Kconfig. And
given that most users are totally happy with an unsigned firmware for
their Allwinner board ...

You could market it as some upsell of your product ;-)

Cheers,
Andre.