[ECOS] Arm user mode

Jonathan Larmour jifl@eCosCentric.com
Tue Apr 8 01:58:00 GMT 2003


Pierre Habraken wrote:
> I discovered yesterday that Arm user mode has not been considered in
> exception processing in hal/arm/arch/current/src/vectors.S.
> Can someone tell me what has been the reason for that (apart the fact
> that most of embedded applications do not need to run user mode
> tasks) ?
> I added a few lines to vectors.S (see patch below) in order to take in
> account the case where an exception occured while the processor was
> running in user mode (this patch does not deal with either FIQ or IRQ
> for the time being).
> I'd like to know advices from Ecos/Redboot experts about this topic...

Okay, given my misunderstanding about Mark's work this patch would be 
worthwhile, *but* can you please do a few things first?

Could it be configurable with a CDL option so as to optionally preserve 
the existing behaviour? Checking for user mode every time adds delay to 
the interrupt/exception path and not every program needs user mode... in 
fact by default no "native" eCos program will.

Could you add a ChangeLog entry?

And then can you submit it (the right way round ;-)) to 
ecos-patches@sources.redhat.com which is the proper place for patch 
submissions.

Thanks for contributing back!

Jifl
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