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

[Klaus Heinrich Kiwi]

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"

>   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?

> +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'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.

> +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>