On Mon, Feb 24, 2025 at 04:54:09PM +0100, Heinrich Schuchardt wrote: > On 24.02.25 15:56, Tom Rini wrote: > > On Mon, Feb 24, 2025 at 09:59:42AM +0100, Heinrich Schuchardt wrote: > > > On 2/24/25 06:55, Sam Edwards wrote: > > > > While the image size is generally a multiple of 8 bytes, this is not > > > > actually guaranteed; some linkers (like LLD) may shave a few bytes off > > > > of the end of output sections if there are no content bytes there. Since > > > > libfdt imposes a hard rule of 8-byte alignment, make the SPL also be > > > > explicit about the alignment when loading the FDT. > > > > > > > > Signed-off-by: Sam Edwards <cfswo...@gmail.com> > > > > --- > > > > common/spl/spl_fit.c | 2 +- > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c > > > > index 49b4df60560..86506d6905c 100644 > > > > --- a/common/spl/spl_fit.c > > > > +++ b/common/spl/spl_fit.c > > > > @@ -397,7 +397,7 @@ static int spl_fit_append_fdt(struct spl_image_info > > > > *spl_image, > > > > * Use the address following the image as target address for the > > > > * device tree. > > > > */ > > > > - image_info.load_addr = spl_image->load_addr + spl_image->size; > > > > + image_info.load_addr = ALIGN(spl_image->load_addr + > > > > spl_image->size, 8); > > > > > > We want to keep the SPL code size as small as possible as on many > > > platforms it is restricted to the cache size. > > > > > > Can't we fix this linker issue in the linker script by properly aligning > > > the SPL image end address? > > > > Size growth is always something to watch for, but not at the expense of > > correctness and saving a few bytes. We really do need to fix the places > > where U-Boot could but doesn't ensure the device tree is correctly > > aligned in memory. > > > > Hello Tom, > > spl_image->load_addr is always a multiple of 8. > > Adding > > . = ALIGN(8)" > > in arch/riscv/cpu/u-boot-spl.lds before > > _end = .; > _image_binary_end = .; > > is all it takes.
But this is generic code and I don't see how we know that in every case every way we could be reading the device tree that it will be at an 8 byte aligned location. There's a number of ways today where it's not, which is what Patrice found as part of updating our own libfdt to one that enforces the alignment check. -- Tom
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