[PATCH] PPC40x: Limit Allocable RAM During Early Mapping

[Grant Erickson]

On 10/30/08 7:03 AM, Josh Boyer wrote:
> On Wed, 29 Oct 2008 14:41:14 -0700
> Grant Erickson <gerickson at nuovations.com> wrote:
>> If the size of RAM is not an exact power of two, we may not have
>> covered RAM in its entirety with large 16 and 4 MiB
>> pages. Consequently, restrict the top end of RAM currently allocable
>> by updating '__initial_memory_limit_addr' so that calls to the LMB to
>> allocate PTEs for "tail" coverage with normal-sized pages (or other
>> reasons) do not attempt to allocate outside the allowed range.
> 
> Nice catch.  I was looking to see if 44x had the same problem, but I
> don't think it does because we simply over-map DRAM there.  Does that
> seem correct to you, or am I missing something on 44x that would cause
> this same problem?

Josh,

Because I do not have 44x hardware to validate against and because this
particular fix was localized to the 40x path, I did not take the time to
walk through the 44x path.

Regards,

Grant