Re: [PATCH v7 2/2] arm64: boot: Support Flat Image Tree
From: Tom Rini
Date: Wed Nov 29 2023 - 15:10:17 EST
On Wed, Nov 29, 2023 at 08:16:20PM +0100, Ahmad Fatoum wrote:
> Hello Tom,
>
> On 29.11.23 20:02, Tom Rini wrote:
> > On Wed, Nov 29, 2023 at 07:59:00PM +0100, Ahmad Fatoum wrote:
> >> Hi,
> >>
> >> a few more comments after decompiling the FIT image:
> >>
> >> On 29.11.23 18:21, Simon Glass wrote:
> >>> + with fsw.add_node('kernel'):
> >>> + fsw.property_string('description', args.name)
> >>> + fsw.property_string('type', 'kernel_noload')
> >>
> >> The specification only says no loading done, but doesn't explain what it
> >> means for a bootloader to _not_ load an image. Looking into the U-Boot commit
> >> b9b50e89d317 ("image: Implement IH_TYPE_KERNEL_NOLOAD") that introduces this,
> >> apparently no loading means ignoring load and entry address?
> >>
> >> I presume missing load and entry is something older U-Boot versions
> >> were unhappy about? Please let me know if the semantics are as I understood,
> >> so I can prepare a barebox patch supporting it.
> >
> > So the matching side for this series in U-Boot is:
> > https://patchwork.ozlabs.org/project/uboot/list/?series=382849&state=*
> >
> > And in short, for IH_TYPE_KERNEL_NOLOAD we do our best to use it
> > in-place. For decompression we allocate some space to decompress to.
>
> Thanks. I am still curious why "kernel" couldn't have been used back then
> with missing entry and load address to arrive at the same result?
Some level or another of historical oversight, yeah.
--
Tom
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