On Fri, 2011-10-21 at 16:39 -0400, David Daney wrote:
> On 10/21/2011 01:18 PM, Noor wrote:
> > what does it mean if cause register IP bits are zero after
> > interrupt exception has already been invoked ?
> It might mean that something was asserting a '1' on to those bits, but
> quit doing so before you could read the cause register, or it could be
> that you get random interrupt exceptions for no reason at all.
In my case it was the following:
index dedef7d..7500c55 100644
@@ -63,6 +63,10 @@
# CN30XX Disable instruction prefetching
or v0, v0, 0x2000
+ # Set CvmCtl[IPTI] to 7
+ ori v0, v0, (7 << 4)
# First clear off CvmCtl[IPPCI] bit and move the performance
# counters interrupt to IRQ 6
li v1, ~(7 << 7)
This should not be needed in the Linux code, but CvmCtl[IPTI] was set to
0 by ROMMON.