Re: [PATCH v16 06/16] lib: fdt: add a helper function for handling memory range property

[AKASHI, Takahiro]

James,

On Fri, Dec 07, 2018 at 10:12:47AM +0000, James Morse wrote:
> Hi Akashi, Will,
> 
> On 06/12/2018 15:54, Will Deacon wrote:
> > On Thu, Dec 06, 2018 at 08:47:04AM -0600, Rob Herring wrote:
> >> On Wed, Nov 14, 2018 at 11:52 PM AKASHI Takahiro
> >> <takahiro.akashi@xxxxxxxxxx> wrote:
> >>>
> >>> Added function, fdt_setprop_reg(), will be used later to handle
> >>> kexec-specific property in arm64's kexec_file implementation.
> >>> It will possibly be merged into libfdt in the future.
> >>
> >> You generally can't modify libfdt files. Any changes will be blown
> >> away with the next dtc sync (there's one in -next now). Though here
> >> you are creating a new location with fdt code. lib/ is just a shim to
> >> the actual libfdt code. Don't put any implementation there. You can
> >> add this to drivers/of/fdt_address.c for the short term, but it still
> >> needs to go upstream.
> >>
> >> Otherwise, the implementation looks fine to me.
> > 
> > I agree, but I don't think there's a real need for us to hack
> > drivers/of/fdt_address.c in the meantime -- let's just target upstream
> > and not carry this in the kernel.
> > 
> > Akashi -- for now, I'll drop the kdump parts of this series which rely
> > on this helper. The majority of the series is actually independent and
> > can go in as-is.
> > 
> > I've pushed out a kexec branch to the arm64 tree for you to take a look
> > at:
> > 
> > https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/log/?h=kexec
> 
> I gave this a quick spin. Without the elfcorehdr/usable-memory-range arm64 needs
> to explicitly forbid kdump via kexec_file_load. (like powerpc does already).

Thank you for pointing this out.

> Without this kdump works, but the second kernel overwrites the first as those DT
> properties are missing.
> 
> I'll post a patch momentarily,

Fine, but anyhow I'm going to submit a new version (*without* kdump),
I will fix the issue along with others.

-Takahiro Akashi


> 
> Thanks,
> 
> James
>