Countdown to 4.9 Branching Point

Sebastian Huber sebastian.huber at
Wed Jul 9 16:00:43 UTC 2008


In order to support operating system functions in critical interrupt 
exceptions we need to set the interrupt disable mask during runtime (see 
"PowerPC exceptions and critical interrupts" thread). We intended to use 
SPRG0 for this purpose which was previously denoted to indicate the 
PR288 bugfix. This change effects all PowerPC BSPs. I searched the code 
for occurrences of PPC_BSP_HAS_FIXED_PR288 and now two things are blurry 
to me:

1. There is a comment in the MVME3100 BSP:

    printk("Testing exception handling Part 1\n");
     * Cause a software exception
    __asm__ __volatile ("sc");
     * Check we can still catch exceptions and return coorectly.
    printk("Testing exception handling Part 2\n");
    __asm__ __volatile ("sc");

     *  Somehow doing the above seems to clobber SPRG0 on the mvme2100.  It
     *  is probably a not so subtle hint that you do not want to use PPCBug
     *  once RTEMS is up and running.  Anyway, we still needs to indicate
     *  that we have fixed PR288.  Eventually, this should go away.

Is there a problem if we use SPRG0 for the interrupt disable mask in 
this case?

2. It seems that the score603e BSP does not use PPC_BSP_HAS_FIXED_PR288?

Joel Sherrill wrote:
> Hi,
> Ralf has laid the groundwork for 4.10 tools and
> I had want to cut the 4.9 branch this week. RTEMS
> itself looks better than it has at any previous
> branching point.
> At this point, I know of a few outstanding
> development efforts I think are close and wanted
> to make 4.9.
> + Chris - some bdbuf work that greatly improves
>   flash file system performance.
> + Thomas - has mentioned a couple of BSPs on the
>   user's list.  Hint (two weeks :-D).  Are they
>   going to make it?
> How close are these? 
> Is there anything else?
> If you have something you want in, submit it ASAP.
> Otherwise, the branch will be cut by the end
> of this week.
> GSOC work will go into 4.10. 

Sebastian Huber, Embedded Brains GmbH

Address : Obere Lagerstr. 30, D-82178 Puchheim, Germany
Phone   : +49 89 18 90 80 79-6
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E-Mail  : sebastian.huber at
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