RE: [PATCH] [RESEND] arm: limit memblock base address for early_pte_alloc

Nicolas Pitre
2012-06-28T06:26:05Z

On Thu, 28 Jun 2012, Kim, Jong-Sung wrote:

> > From: Dave Martin [mailto:dave.martin@linaro.org]
> > Sent: Thursday, June 28, 2012 1:02 AM
> >
> > For me, it appears that this block just contains the initial region passed
> > in ATAG_MEM or on the command line, with some reservations for
> > swapper_pg_dir, the kernel text/data, device tree and initramfs.
> >
> > So far as I can tell, the only memory guaranteed to be mapped here is the
> > kernel image: there may be no guarantee that there is any unused space in
> > this region which could be used to allocate extra page tables.
> > The rest appears during the execution of map_lowmem().
> >
> > Cheers
> > ---Dave
>
> Thank you for your comment, Dave! It was not that sophisticated choice, but
> I thought that normal embedded system trying to reduce the BOM would have a
> big-enough first memblock memory region. However you're right. There can be
> exceptional systems. Then, how do you think about following manner:
[...]

This still has some possibilities for failure.

Please have a look at the two patches I've posted to fix this in a
better way.

Nicolas