[PATCH v2 2/2] ARM: OMAP2+: Pad SPL binary to 8-byte alignment before DTB

[Tom Rini]

On Mon, Jan 12, 2026 at 06:38:19PM +0530, Anshul Dalal wrote:
> On Mon Jan 12, 2026 at 3:41 PM IST, Beleswar Padhi wrote:
> > The OMAP2 SPL linker script (also used for K3 platforms) currently uses
> > a 4-byte alignment directive after the __u_boot_list section. This
> > alignment directive only advances the location counter without padding
> > the actual binary output.
> >
> > When objcopy extracts u-boot-spl-nodtb.bin, it includes only actual
> > data, stopping at the last byte of __u_boot_list (e.g., 0x41c359fc),
> > not an aligned address (e.g., 0x41c35a00). So, when the FIT image
> > containing device trees is concatenated to the SPL binary, it gets
> > appended at this unaligned file size, causing libfdt validation failure.
> >
> > To fix this, move the alignment directive into the __u_boot_list section
> > itself and make it 8-byte aligned as per DT spec. This forces the linker
> > to include padding as part of the section data, ensuring objcopy
> > includes the padding bytes in the binary and the appended FIT image
> > starts at an 8-byte aligned boundary.
> >
> > Reported-by: Anshul Dalal <anshuld at ti.com>
> > Closes: https://lore.kernel.org/u-boot/DFJ950O0QM0D.380U0N16ZO19E@ti.com
> > Fixes: 0535e46d55d7 ("scripts/dtc: Update to upstream version v1.7.2-35-g52f07dcca47c")
> > Signed-off-by: Beleswar Padhi <b-padhi at ti.com>
> > ---
> > v2: Changelog:
> > 1. Get rid of extra ALIGN() directive, replace it with a comment
> > 2. Carry Reported-by, Closes and Fixes tag.
> >
> > Link to v1:
> > https://lore.kernel.org/all/20260109190026.58464-3-b-padhi@ti.com/
> >
> >  arch/arm/mach-omap2/u-boot-spl.lds | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/arm/mach-omap2/u-boot-spl.lds b/arch/arm/mach-omap2/u-boot-spl.lds
> > index 3bb759d8a1c..5ad169a37b7 100644
> > --- a/arch/arm/mach-omap2/u-boot-spl.lds
> > +++ b/arch/arm/mach-omap2/u-boot-spl.lds
> > @@ -35,9 +35,13 @@ SECTIONS
> >  	. = ALIGN(4);
> >  	__u_boot_list : {
> >  		KEEP(*(SORT(__u_boot_list*)));
> > +		/*
> > +		 * Ensure 8-byte alignment at the end of the last section before
> > +		 * DTB is appended, to satisfy DT spec alignment requirements
> > +		 */
> > +		. = ALIGN(8);
> 
> I wonder if there could be a better way to handle this constraint,
> currently we have two major problems with this approach:
> 
> 1. All platforms facing similar alignment issues would have to modify
> their linker scripts.

Yes, agreed.

> 2. The FDT only gets appended directly to SPL binary in cases of
> CONFIG_SPL_SEPARATE_BSS. Otherwise we do (SPL binary + BSS + FDT) as per
> the $(obj)/$(SPL_BIN)-dtb.bin make target. Which means BSS would have to
> be 8-byte aligned as well as the SPL binary.
> 
> I wonder if we could have a new make target for say
> u-boot-spl-nodtb-aligned.bin which is just (SPL binary + optionally BSS
> + padding for alignment) and at runtime we modify the fdt addr in gd to
> point to the correctly aligned address?

Looking back at
https://lore.kernel.org/all/87h65ihumb.fsf@bloch.sibelius.xs4all.nl/ we
can use dd as a portable way to ensure that a file ends with 8-byte
alignmnent by doing:
dd if=testfile bs=8 conv=sync of=testfile_pad
and we get a zero-padded 8-byte aligned output file, and at the end of
that we can concatenate our dtb.

That would just leave the FIT images as the issue, which Marek provided
feedback on in 1/2, yes?

-- 
Tom
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