[PATCH u-boot v2019.04-aspeed-openbmc v2 6/6] config: ast2600: Reduce SPL image size

[Joel Stanley]

On Wed, 27 Jan 2021 at 19:46, Klaus Heinrich Kiwi
<klaus at linux.vnet.ibm.com> wrote:
>
> Hi Joel,
>
> On 1/27/2021 4:00 AM, Joel Stanley wrote:
> > This modifies some features of the SPL to ensure it fits in the 64KB
> > payload size.
> >
> > This set of options reduceds the binary size by 4760 bytes with GCC 10.
> typo here..
>
>
> > Signed-off-by: Joel Stanley <joel at jms.id.au>
> > ---
> >   configs/ast2600_openbmc_spl_emmc_defconfig | 6 +++++-
> >   1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/configs/ast2600_openbmc_spl_emmc_defconfig b/configs/ast2600_openbmc_spl_emmc_defconfig
> > index c55a70c5c1c9..345225131075 100644
> > --- a/configs/ast2600_openbmc_spl_emmc_defconfig
> > +++ b/configs/ast2600_openbmc_spl_emmc_defconfig
> > @@ -2,8 +2,9 @@ CONFIG_ARM=y
> >   CONFIG_SYS_CONFIG_NAME="evb_ast2600a1_spl"
> >   CONFIG_SYS_DCACHE_OFF=y
> >   CONFIG_POSITION_INDEPENDENT=y
> > -CONFIG_SPL_SYS_THUMB_BUILD=y
> Are we sure this is reducing the size? From the Kconfig file..
> "Thumb instruction set provides better code density"

This is a defconfing change only. We are still building with thumb;
check the output .config.

>
> >   CONFIG_SYS_THUMB_BUILD=y
> > +# CONFIG_SPL_USE_ARCH_MEMCPY is not set
> > +# CONFIG_SPL_USE_ARCH_MEMSET is not set
> Ack, sounds good.
>
> >   CONFIG_SPL_LDSCRIPT="arch/$(ARCH)/mach-aspeed/ast2600/u-boot-spl.lds"
> >   CONFIG_ARCH_ASPEED=y
> >   CONFIG_SYS_TEXT_BASE=0x10000
> > @@ -51,6 +52,8 @@ CONFIG_BOARD_EARLY_INIT_F=y
> >   CONFIG_SPL_SYS_MALLOC_SIMPLE=y
> >   CONFIG_SPL_STACK_R=y
> >   CONFIG_SPL_SEPARATE_BSS=y
> > +# CONFIG_TPL_BANNER_PRINT is not set
> Is this unrelated?

Yes, this can be dropped.

>
> > +CONFIG_SPL_FIT_IMAGE_TINY=y
> I am unsure about this one. I know that we *may* need that to
> secureboot, but we may loose good tracking of the image that
> was actually loaded in the fdt, which sounds like a desirable
> feature in secureboot scenarios, specially where we don't have
> a TPM for measurements.

I don't see any need in our design for updating the u-boot device tree
with any information from the SPL. If we have that requirement in the
future we can consider turning this code on.

>
> I'd put that low on the priority list (i.e., below the ymodem support)?
>
> >   CONFIG_SPL_DM_RESET=y
> >   CONFIG_SPL_RAM_SUPPORT=y
> >   CONFIG_SPL_RAM_DEVICE=y
> > @@ -130,6 +133,7 @@ CONFIG_SYSRESET=y
> >   CONFIG_WDT=y
> >   CONFIG_USE_TINY_PRINTF=y
> >   # CONFIG_REGEX is not set
> bikeshedding, but I'd recommend combining the necessary changes to make
> SPL fit the 64KB size in one patch, and enable the SPL signing in another
> patch in the same set, while leaving out unrelated / optional changes
> to another set.

ok.

>
> > +CONFIG_SPL_TINY_MEMSET=y
> ack
>
> >   CONFIG_TPM=y
> >   CONFIG_SPL_TPM=y
> >   # CONFIG_EFI_LOADER is not set
>
> Thanks,
>
>   -Klaus
>
> --
> Klaus Heinrich Kiwi <klaus at linux.vnet.ibm.com>