[U-Boot] Giving control to standalone app.

[U-Boot] Giving control to standalone app.

[mazen.e]

Dear all,

At the moment U-Boot branches to the OS entry point, U-Boot  is dead and no
longer exists, does this property hold also when u-boot loads a standalone
application.

In fact, I want to 'give control' to a standalone application,  what does
exactly  the word 'give control' mean? e.g. 'giving control' is established 
by implementing an infinite loop in the standalone such that the  body of
the loop executes continuously specific tasks or responding to particular
interrupts? in such case what happens to u-boot? what if after a particular
event in the standalone  app I want to return to u-boot?

Please excuse me for this beginner question.


Best wishes.



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[U-Boot] Giving control to standalone app.

[Jeroen Hofstee]

On 06-07-14 13:10, mazen.e wrote:
> Dear all,
>
> At the moment U-Boot branches to the OS entry point, U-Boot  is dead and no
> longer exists, does this property hold also when u-boot loads a standalone
> application.
>
> In fact, I want to 'give control' to a standalone application,  what does
> exactly  the word 'give control' mean? e.g. 'giving control' is established
> by implementing an infinite loop in the standalone such that the  body of
> the loop executes continuously specific tasks or responding to particular
> interrupts? in such case what happens to u-boot? what if after a particular
> event in the standalone  app I want to return to u-boot?
>
> Please excuse me for this beginner question.
>
>
Yes you loop as long as you want to keep doing something, when you
return you should end up in u-boot again.

Regards,
Jeroen

[U-Boot] Giving control to standalone app.

[mazen.e]

Dear 

Many thanks for your reply.

But what if mistakenly or accidentally the standalone application write to
the memory where u-boot resides, would that cause the standalone application
to crash? Otherwise (in case the standalone application has written to
u-boot memory without crash )  what happens if the standalone app exit the
loop.


Regards, 






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[U-Boot] Giving control to standalone app.

[Albert ARIBAUD]

Hi mazen.e,

On Sun, 6 Jul 2014 06:00:03 -0700 (PDT), "mazen.e"
<mazen.ezzeddine@gmail.com> wrote:

> Dear 
> 
> Many thanks for your reply.
> 
> But what if mistakenly or accidentally the standalone application write to
> the memory where u-boot resides, would that cause the standalone application
> to crash? Otherwise (in case the standalone application has written to
> u-boot memory without crash )  what happens if the standalone app exit the
> loop.

You're actually asking the very general question "what happens if some
code behaves badly", and the very general answer is "then bad things
happen".

Specifically, you do realize already that if an application overwrites
the U-Boot code in RAM, then upon returning it'll give control back to
a corrupted U-Boot, which can have all sorts of bad effects.

> Regards, 

Amicalement,
-- 
Albert.

[U-Boot] Giving control to standalone app.

[mazen.e]

OK, my best thanks for your great answer. 



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