[U-Boot] Regarding learning reference of uboot loading secondary uboot

[pratapnaidu at gmail.com]

Hi Simon,
                Thanks for of your time and quick replies.  The idea seems to be good, but still confused with the way to implement it. Please help me to give a final thought to solve this with the existing framework, sorry for my inexperience with u-boot, kindly enlighten with the following:

1) How to sign the primary and secondary u-boot image with the same key, after that  do i need to write a routine similar to  “bootm_find_os”  or “bootm_find_loadables" to find the secondary uboot image and load it into the memory,
2) can we have a dummy fit image with only secondary u-boot image within the .its file for the first u-boot loader
3)Sorry to ask you this, do you have any  partial code i can follow and shred some light to carry on further.


I really thanks you to answer my all questions with patience,i would have not disturbed you, but because of project dead-line i was forced to be carried out with the situation.

Thanks,
pratap







> On May 23, 2015, at 2:12 PM, Simon Glass <sjg at chromium.org> wrote:
> 
> Hi,
> 
> On 23 May 2015 at 13:02, Maddimsetty Pratap <pratapnaidu at gmail.com> wrote:
>> Hi Simon,
>>              Thanks for you quick reply and sorry for the confusion over
>> forum,here is my request for help
>> 
>>             1)  Do you know any repository which had already did it
>> "verify second u-boot signature" over beaglebone.
> 
> I'm not sure if this was done or not. You could look in cros/amxx here:
> 
> https://chromium.googlesource.com/chromiumos/third_party/u-boot/+/chromeos-v2013.06
> 
> or a newer version that doesn't currently support beaglebone.
> 
> https://chromium.googlesource.com/chromiumos/third_party/u-boot/+/chromeos-v2015.07-rc1
> 
> The Chrome OS implementation uses the same crypto but has custom
> binary data structures. I'm working a bit on trying to bridge the gap
> but we are not there yet.
> 
> So the easiest way to make this work is probably to use the FIT
> signature verification and put your second U-Boot into the FIT. That
> should handle the verification and then after it loads you can turn
> off the cache and jump to it. It already works on Beaglebone and the
> only difference is that it is currently set up to load a kernel, but
> you want to load U-Boot.
> 
>> 
>>             2) Please verify and confirm the following link, if i was going
>> in the right direction.
>> 
>> http://git.chromium.org/gitweb/?p=chromiumos/third_party/u-boot.git;a=commit;h=b9e8864294d8f2143ce17b4e0d4ba019b6348199
>> 
>> Thanks,
>> pratap
>> 
> 
> Regards,
> Simon
> 
>> 
>> Thanks,
>> pratap
>> 
>> On Thu, May 21, 2015 at 6:32 PM, Simon Glass <sjg at chromium.org> wrote:
>>> 
>>> Hi,
>>> 
>>> It's here:
>>> 
>>> https://chromium.googlesource.com/chromiumos/third_party/u-boot
>>> 
>>> in branch chromeos-v2013.06. It is implemented for chromeos_peach.
>>> 
>>> If you have further questions, please send them to the U-Boot mailing list
>>> and cc me.
>>> 
>>> Regards,
>>> Simon
>>> 
>>> 
>>> On 21 May 2015 at 17:25, Maddimsetty Pratap <pratapnaidu at gmail.com> wrote:
>>>> 
>>>> Hi Simon,
>>>>               I am apologize to e-mail you directly. In one of your
>>>> presentations regarding FIT, you had stated uboot loading a signed secondary
>>>> uboot loader in chromium. I would be glad if you provide me with any
>>>> reference regarding the same.
>>>> 
>>>> 
>>>> Here is the statement from LWN.net.
>>>> 
>>>> 
>>>> "Chrome OS starts up U-Boot, loads and verifies a second U-Boot, loads
>>>> and verifies a kernel and jumps to it all in under 700ms on a modern SoC"
>>>> 
>>>> Thanks,
>>>> pratap
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>> 
>>> 
>> 
>> 
>> 
>> --
>> pratap naidu