MMU failure, Virtex4-FX60

Grant Likely grant.likely at
Tue Jan 8 05:21:21 EST 2008

On 1/7/08, Robert Woodworth <rwoodworth at> wrote:
> Hello!
> I'm building a new Virtex4-FX60 device.  I have built it with the new
> MPMC3 and a 256MB SO-DIMM.  It works successfully with a "mem-test" type
> embedded program.
> I cannot get it to boot a Linux kernel.  I have traced it down to the
> MMU not getting mapped correctly.
> I can load the kernel via jtag, get the pre-boot messages on the serial
> but then when it tries to jump to 0xc0002218 (start_here: head_4xxx.S)
> it fails with a "Machine check exception; invalid instruction address".
> Using the debugger and examining the memory once the mmu is suppose to
> be configured, I see that it is not mapping 0xc0000000  to the proper
> location.  I'm sure I've set something up wrong in my FPGA and I need to
> re-synthesize.  But what?

Hmmm, I haven't seen that failure mode before.  MMU handling on an of
my virtex platforms has never been a problem.  Take a look at the TLB
registers to see how they are configured to see if the mappings are
really getting written.

What kernel version are you using?


Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
grant.likely at
(403) 399-0195

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