[PATCH V4] powerpc/prom: Export device tree physical address via proc

Grant Likely grant.likely at secretlab.ca
Fri Jul 16 02:22:21 EST 2010

On Thu, Jul 15, 2010 at 9:19 AM, Matthew McClintock <msm at freescale.com> wrote:
> On Thu, 2010-07-15 at 00:21 -0600, Grant Likely wrote:
>> On Wed, Jul 14, 2010 at 9:18 AM, Matthew McClintock
>> <msm at freescale.com> wrote:
>> > To build a proper flat device tree for kexec we need to know which
>> > memreserve region was used for the device tree for the currently
>> > running kernel, so we can remove it and replace it with the new
>> > memreserve for the kexec'ed kernel
>> >
>> > Signed-off-by: Matthew McClintock <msm at freescale.com>
>> Hi Matthew.
>> I don't understand.  Why does userspace need to know about the old
>> memreserve sections?  Doesn't kexec tear down all of the old
>> allocations anyway?  How are they relevant for constructing the dtb
>> for the kexec kernel?  I'll need a lot more details before I consider
>> merging this.
>> Also, please cc: me and Ben Herrenschmidt on powerpc related device
>> tree changes.
>> Cheers,
>> g.
> Grant,
> Thanks for taking a look. My first thought was to just blow away all the
> memreserve regions and start over. But, there are reserve regions for
> other things that I might not want to blow away. For example, on mpc85xx
> SMP systems we have an additional reserve region for our boot page.

What is your starting point?  Where does the device tree (and
memreserve list) come from
that you're passing to kexec?  My first impression is that if you have
to scrub the memreserve list, then the source being used to
obtain the memreserves is either faulty or unsuitable to the task.


More information about the Linuxppc-dev mailing list