Re: [PATCH 1/2] powerpc: add 16K/64K pages support for the 44x PPC32 architectures.

[Hollis Blanchard <hollisb@us.ibm.com>]

On Tue, 2008-11-11 at 08:19 -0500, Josh Boyer wrote:
> On Fri, Oct 31, 2008 at 06:23:28PM -0500, Hollis Blanchard wrote:
> >On Wed, Oct 22, 2008 at 9:28 AM, Christian Ehrhardt
> ><ehrhardt@linux.vnet.ibm.com> wrote:
> >> Hi Ilya,
> >> I just tried your patch on my 440 board because it would help us in our
> >> environment.
> >> Unfortunately I run into a bug on early boot (mark_bootmem).
> >>
> >> A log can be found in this mail, this is the bug when running with 64k page
> >> size.
> >> I tried this with and without your 2/2 265k patch and also with page size
> >> configured to 16k, the error is the same in all cases.
> >>
> >> I used an earlier version of your patch in the past and it worked fine.
> >> Applying this old patch causes the same problem.
> >> Therefore I expect that there was some other code changed that breaks with
> >> page size != 4k.
> >
> >This patch seems to solve the problem for me, but I have to run and
> >haven't yet worked out if it's the right fix.
> >
> >diff --git a/mm/bootmem.c b/mm/bootmem.c
> >--- a/mm/bootmem.c
> >+++ b/mm/bootmem.c
> >@@ -300,7 +300,7 @@ static int __init mark_bootmem(unsigned
> >                unsigned long max;
> >
> >                if (pos < bdata->node_min_pfn ||
> >-                   pos >= bdata->node_low_pfn) {
> >+                   pos > bdata->node_low_pfn) {
> >                        BUG_ON(pos != start);
> >                        continue;
> >                }
> >@@ -399,7 +399,7 @@ int __init reserve_bootmem(unsigned long
> >        unsigned long start, end;
> >
> >        start = PFN_DOWN(addr);
> >-       end = PFN_UP(addr + size);
> >+       end = PFN_DOWN(addr + size);
> >
> >        return mark_bootmem(start, end, 1, flags);
> > }
> 
> 
> Hollis,  if I'm understanding things correctly this patch is no
> longer needed if we do the memory reserve in the boot wrapper for
> the errata.  Correct?

Correct.

-- 
Hollis Blanchard
IBM Linux Technology Center