[U-Boot] p4080ds starts OS with MSR[EE]=1 and DEC armed?

Jimi Xenidis jimix at watson.ibm.com
Sun Mar 13 16:46:44 CET 2011


On Mar 12, 2011, at 4:56 PM, Kumar Gala wrote:
> 
> 
> On Mar 3, 2011, at 8:59 AM, Jimi Xenidis wrote:
> 
>> I was surprised to find myself at the decrement interrupt when running my new stuff.
>> That is against ePAPR, right?
>> Does u-boot at least make sure that the DEC is set to some large value before it leaps at me?
>> I don't mind forcing EE=0 but I'd like to make sure I make it that far into the code :)
>> -JX
> 
> Jimi,
> 
> Not sure how or why you are seeing this, but u-boot should disable interrupts in common/cmd_bootm.c
> 
> Look for disable_interrupts() -> this should set MSR[EE] = 0.

Sorry, this is my brain fart.
I was running my unit tests (on SimiCS p4080ds) and when I set MSR[EE]=1 to get a doorbell, I got a DEC (as one should according to interrupt order).
Turns out that TSR[DIS] was on when my program took over, and this is ePAPR legal.
I need to reset the DEC in my code.

Sorry for the confusion.
-JX

> 
> - k
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