Hi Eugen,
On Thu, 15 Dec 2022 at 06:37, Eugen.Hristev@microchip.com wrote:
On 12/15/22 16:24, Simon Glass wrote:
Hi Eugen,
On Thu, 15 Dec 2022 at 03:58, Eugen Hristev eugen.hristev@microchip.com wrote:
Newer DTC require that the DTB start address is aligned at 8 bytes. In the u-boot.bin case, the u-boot-nodtb.bin is concatenated with the DTB, but there is no alignment/padding to the next 8byte aligned address. This causes the board to fail booting, because the FDT will claim that the DTB inside u-boot.bin is not a valid DTB, it will fail with -FDT_ERR_ALIGNMENT. To solve this, have the u-boot binary `_end` aligned with 8 bytes. The objcopy in the Makefile will create the u-boot-nodtb.bin and it has to be truncated to 8 bytes to correspond to the u-boot.map file which will have the `_end` aligned to 8 bytes. The lds files which use devicetrees have been changed to align the `_end` tag with 8 bytes.
This patch is also a prerequisite to have the possibility to update the dtc inside u-boot to newer versions (1.6.1+)
Signed-off-by: Eugen Hristev eugen.hristev@microchip.com
Hi,
I could not test all affected boards, it's an impossible task. I tried this on at91 boards which I have, and ran the CI on denx. I cannot guarantee that no other boards are affected, so this patch is a bit of an RFC. If the u-boot-nodtb.bin does not have the size equal with the corresponding one in u-boot.map, the binary_size_check will fail at build time with something like this:
u-boot.map shows a binary size of 502684 but u-boot-nodtb.bin shows 502688
Thanks, Eugen
Makefile | 2 ++ arch/arm/cpu/armv8/u-boot.lds | 4 ++-- arch/arm/cpu/u-boot-spl.lds | 1 + arch/arm/cpu/u-boot.lds | 1 + arch/arm/lib/elf_arm_efi.lds | 5 +++++ arch/arm/mach-at91/arm926ejs/u-boot-spl.lds | 2 +- arch/arm/mach-at91/armv7/u-boot-spl.lds | 2 +- arch/arm/mach-zynq/u-boot-spl.lds | 2 +- arch/mips/cpu/u-boot.lds | 2 +- arch/sandbox/cpu/u-boot.lds | 6 ++++++ arch/sh/cpu/u-boot.lds | 2 ++ board/ti/am335x/u-boot.lds | 1 + tools/binman/test/u_boot_binman_embed.lds | 2 +- 13 files changed, 25 insertions(+), 7 deletions(-)
diff --git a/Makefile b/Makefile index 9d84f96481..b4d387bcce 100644 --- a/Makefile +++ b/Makefile @@ -1317,6 +1317,8 @@ endif
u-boot-nodtb.bin: u-boot FORCE $(call if_changed,objcopy_uboot) +# Make sure the size is 8 byte-aligned.
@truncate -s %8 $@ $(BOARD_SIZE_CHECK)I agree this line is needed, since otherwise we will only get 4-byte alignment. But it would be better if we could have the linker scripts fill bytes out to the required alignment. Is that possible?
Reviewed-by: Simon Glass sjg@chromium.org
Regards, Simon
Hi Simon,
I tried to check the objcopy option --pad-to , to use it at the time of objcopy, but this requires a real number to be passed to it. And this number could only be found by inspecting the u-boot.map file, since u-boot-nodtb.bin still does not exist. And if we pad to the size specified in u-boot.map, then binary_size_check does not make much sense anymore, as we will basically use the same information to fit the file, and it will always pass with a success. (even if we would pad many more bytes than 4 ) Hence it would lose it's purpose ( binary_size_check ), which I think was created to make sure no objects were lost when doing objcopy and creating the u-boot-nodtb.bin file.
Yes, I was more thinking of something like:
fill { . = ALIGN(8); QUAD(0) };
in the link script, or something that actually writes the padding bytes.
On a side note, do you think I covered all the implied lds files ? I would hate to break someone's boards.
If CI passes you should be able to rely on the binary size check.
And also, P.S. : I would require to have the same change when building a FIT image with mkimage... all subimages inside a FIT must be aligned to 8 bytes. However mkimage only aligns the start address and header of the FIT (-B option). Out of your knowledge, is this possible and where could I have a look to do this change ?
I lean towards the view that this 8-byte alignment is a bad idea.
Does libfdt itself support this sort of thing? We'll need to be able to tell it to align the value of a property to 8 bytes, both in the sw interface and the normal one.
For binman to support it this is pretty easy once the sw interface is updated - see _add_node() in fit.py.
For mkimage to support it, see fit_import_data(). Perhaps need a libfdt function like fdt_setprop_align()...?
Regards, Simon