On Wed, 12 Nov 2008 15:37:43 +1100
Benjamin Herrenschmidt <[EMAIL PROTECTED]> wrote:

> On Tue, 2008-11-11 at 18:06 -0600, Hollis Blanchard wrote:
> > The current CHIP11 errata truncates the device tree memory node, and 
> > subtracts
> > (hardcoded) 4096 bytes. This breaks kernels with larger PAGE_SIZE, since the
> > bootmem allocator assumes that total memory is a multiple of PAGE_SIZE.
> > 
> > Instead, use a device tree memory reservation to reserve only the 256 bytes
> > actually affected by the errata, leaving the total memory size unaltered.
> > 
> > Signed-off-by: Hollis Blanchard <[EMAIL PROTECTED]>
> 
> While I prefer this approach, won't it break kexec ?

Break it how?  Particularly given that kexec doesn't work on 4xx (yet).

> I don't understand why we don't just have a bit of code in the kernel
> itself that reserve that page on 44x at boot time and be done with it.
> 
> It's like we are trying to be too smart and over-engineer the solution.

I don't think that's it.  I think it's more that we're opportunistic and
the wrapper is the easiest place to do this, given that U-Boot itself
will be doing the reserve for platforms that don't require the
wrapper.

So we could do the fixup in-kernel, but how do you do that
deterministically given that U-Boot might have already done it?

josh
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