Re: User mode address error problems on 7763

Dale Larson
2009-09-15T11:54:35Z

On Tue, Sep 15, 2009 at 3:39 AM, Matt Fleming <matt@console-pimps.org> wrote:
> OK, these are unexpected fixups and similar to the issues I've been
> seeing. The current train of thought is that these unaligned accesses
> are a symptom of having aliases in the D-cache. I've been trawling
> through the cache/tlb code for SH4 and so far haven't found the bug.
>
> As a little experiment, could you try bumping the page size from 4K to
> 8K and see if the unaligned accesses go away? If they are caused by
> D-cache aliasing, in theory, they should disappear with 8K pages.

The 7763 only supports 1K, 4K, 64K and 1M pages. Would a 64K page
yield any useful info?

> Can you reliably reproduce this? A little tip when doing development is
> to turn on Verbose BUG() reporting, which is located in the Kernel
> Hacking menu. That'll give you a line and number in the source file.

I can certainly try. I see I forget to turn on BUG(). I'll post
results. Anything I can do to assist in finding this I'm open to.
Clearly I don't want to run my system without I/D Cache. :)

Thanks,
Dale Larson
Johnson Controls, Inc