Hey Peter, On Friday, 29 May 2026 at 8:18 PM, Peter Robinson <[email protected]> wrote:
> Hi Sam, > > > Since 5c71f8110, the u-boot.elf produced by dragonboard410c_defconfig no > > longer fits in the 1MiB aboot partition it is intended for. > > > > To be precise, this issue occurs on toolchains that have a linker with a > > COMMONPAGESIZE > 4K. Since u-boot is hardcoded for 4K granules, we > > ensure that the linker doesn't try to align to anything larger than > > that, otherwise we're just filling our ELFs with a bunch of useless > > zeros. > > Is this just applicable to ELFs or can it be applied more widely? I'm not completely sure :) These linker options control ld's constants [1]. COMMONPAGESIZE is used to align sections in arm32/arm64 linker scripts [2]. Whether this affects anything else besides that is not fully clear to me. > > > Suggested-by: Stephan Gerhold <[email protected]> > > Signed-off-by: Sam Day <[email protected]> > Tested-by: Peter Robinson <[email protected]> > > Tested on a Rock960 where the elf output went from 9498864 to 9437424 This isn't much of a change at all, I wonder what toolchain you're using, and what its default COMMONPAGESIZE is? You can run the snippet below to find out. ```sh echo 'SECTIONS { cps = CONSTANT(COMMONPAGESIZE); }' > /tmp/pg.lds && echo 'int x;' | aarch64-linux-gnu-gcc -x c - -c -o /tmp/pg.o && aarch64-linux-gnu-ld -T /tmp/pg.lds -o /tmp/pg.elf /tmp/pg.o && aarch64-linux-gnu-nm /tmp/pg.elf \ | awk '/cps/{print strtonum("0x"$1), "("$1")"}' ``` [1]: https://sourceware.org/binutils/docs/ld/Symbolic-Constants.html [2]: https://github.com/search?q=repo%3Au-boot%2Fu-boot%20COMMONPAGESIZE&type=code Cheers, -Sam > > > --- > > arch/arm/config.mk | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/arch/arm/config.mk b/arch/arm/config.mk > > index a7eff84a267..bce9a31e966 100644 > > --- a/arch/arm/config.mk > > +++ b/arch/arm/config.mk > > @@ -112,6 +112,14 @@ endif > > # needed for relocation > > LDFLAGS_u-boot += -pie > > > > +ifeq ($(CONFIG_ARM64),y) > > +# U-Boot uses fixed 4K granules, so we force the linker to match. > > +# Otherwise, we're subject to toolchain preferences, (e.g Fedora's > > +# aarch64-linux-none toolchain selects 64K granules) and we end up wasting > > +# a lot of space in ELFs with MMU_PGPROT enabled. > > +LDFLAGS_u-boot += -z common-page-size=0x1000 -z max-page-size=0x1000 > > +endif > > + > > # > > # FIXME: binutils versions < 2.22 have a bug in the assembler where > > # branches to weak symbols can be incorrectly optimized in thumb mode > > > > --- > > base-commit: 987907ae4bcc5d6055bdf7d318a3edf53e14d5fa > > change-id: 20260528-4k-page-alignment-6cb594a073b0 > > > > Best regards, > > -- > > Sam Day <[email protected]> > > > > >
