[PATCH v5.5] of/fdt: export fdt blob as /sys/firmware/fdt

Grant Likely grant.likely at linaro.org
Fri Nov 21 06:58:47 PST 2014

On Wed, Nov 19, 2014 at 6:32 PM, Geoff Levand <geoff.levand at linaro.org> wrote:
> Hi Ian,
> On Wed, 2014-11-19 at 13:09 +0000, Ian Campbell wrote:
>> On Tue, 2014-11-18 at 22:11 +0000, Grant Likely wrote:
>> > > > * It also helps with exposing the reserved map to userspace, but kexec
>> > > >   has done without that feature for years, and it is in the process of
>> > > >   being deprecated in favour of /reserved-memory anyway.
>> > >
>> > > This is the first I'd heard of the reserve map being deprecated, and
>> > > we're going to have DTs with reserved map entries for a long time going
>> > > forwards.
>> >
>> > Deprecated, not removed or disabled. It will still work pretty much
>> > forever, but users should be encouraged to move to the reserve-memory
>> > tree.
>> I'm curious why that should be for the "OS should never touch this, here
>> be dragons" type memory, what are the benefits of the new scheme in that
>> case?
> /memreserve/ device tree entries are not available in /proc/device-tree,
> but reserved-memory nodes are.  Some solution is needed to get all
> reserved memory info into the dtb passed to the second stage kernel
> during a kexec re-boot.

We could also add a file to export the memreserve sections, but now
that we've got the whole DTB exported, I think it should be fine for
that also to be the interface for obtaining memreserve.


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