ISR Argument Proposal Request

[Joel Sherrill]

gregory.menke at gsfc.nasa.gov wrote:
> 
> Joel Sherrill writes:
>  >
>  > Till,
>  >
>  > I think that we are all as much in agreement over this as we
>  > will ever be.  Let's see if I can summarize and request that
>  > you write up the API changes with a list of "key" area to
>  > change.
>  >
>  > Some issues that must be resolved:
>  >
>  >  + should rtems_interrupt_catch be backward compatable and
>  >    this functionality have a new entry point?  I lean to yes.
>  >  + should this feature be optional and conditionally compiled?
>  >
>  > The development plan needs to have volunteers for each of
>  > the following:
>  >
>  >   + generic change from table of handlers to table of
>  >     handlers/arguments
>  >   + each port's irq handling
>  >   + API changes to original interrupt API, ppc, x86, and ARM
>  >   + documentation changes
>  >   + any work break down I am missing?
>  >
>  >   NOTE: When you change a port, I would consider that to include
>  >   getting all the BSPs modified.  Everything should still build.
>  >   I regularly build all BSPs so this is somethign I can provide
>  >   feedback on.
>  >
>  > We can't start this until we are confident all
>  > the ports will get updated.
> 
> I can work on the mips side and test it on our hardware once theres
> consensus on the implementation.
> 
> I would like to preserve the ability to pass a pointer to the stack
> frame to the vector, preferably as an extra argument to the vector
> call itself.  This is essential for some of our interrupt processing
> and avoids unpleasant hacks.  In fact, we don't use the vector # at
> all at present.

I hesitated mentioning this but in fact a handful of 
ports which pass a 2nd argument which is the address of the
exception/interrupt stack frame.  The format of the data
at that pointer is port defined although I believe the
name of the data type is universal.  So I would REALLY
like to see:

void _ISR_HANDLER( void *, frame * );

with better names.  :)

The frame * is generally also known at ISR vectoring time.

> WRT backwards compatibility, as long as we can continue symbolically
> refer to bsp-specific interrupt lines when calling
> rtems_interrupt_catch, most any changes are fine with us.
> 
> Gregm

-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel at OARcorp.com                 On-Line Applications Research
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