On 1/12/26 11:05 PM, Tom Rini wrote:
On Mon, Jan 12, 2026 at 10:56:04PM +0100, Marek Vasut wrote:
On 1/12/26 5:48 PM, Tom Rini wrote:
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 <[email protected]>
Closes: https://lore.kernel.org/u-boot/[email protected]
Fixes: 0535e46d55d7 ("scripts/dtc: Update to upstream version
v1.7.2-35-g52f07dcca47c")
Signed-off-by: Beleswar Padhi <[email protected]>
---
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/[email protected]/
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/[email protected]/ 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.
You still need to make sure there is a symbol generated by the linker that
points at the END of the u-boot binary . dd happens too late, so you cannot
do that. The alignment has to be done by the linker, in the linker script I
think.
I guess the question is are we:
a) Look at $sym for device tree, and so $sym must be 8-byte aligned.
b) Look at end of self, rounded up to alignment, for device tree
c) (a) on some platforms (b) on other platforms
?
$sym is at the end, which is not always 8 byte aligned . See
lib/fdtdec.c for the relevant code:
1243 static void *fdt_find_separate(void)
1244 {
1245 void *fdt_blob = NULL;
1246
1247 if (IS_ENABLED(CONFIG_SANDBOX))
1248 return NULL;
1249
1250 #ifdef CONFIG_XPL_BUILD
1251 /* FDT is at end of BSS unless it is in a different memory
region */
1252 if (CONFIG_IS_ENABLED(SEPARATE_BSS))
1253 fdt_blob = (ulong *)_image_binary_end;
1254 else
1255 fdt_blob = (ulong *)__bss_end;
