[U-Boot] [PATCH v3 2/2] sunxi: binman: Add U-Boot binary size check

[Måns Rullgård]

Maxime Ripard <maxime.ripard at free-electrons.com> writes:

> The U-Boot binary may trip over its actual allocated size in the storage.
> In such a case, the environment will not be readable anymore (because
> corrupted when the new image was flashed), and any attempt at using saveenv
> to reconstruct the environment will result in a corrupted U-Boot binary.
>
> Reviewed-by: Andre Przywara <andre.przywara at arm.com>
> Signed-off-by: Maxime Ripard <maxime.ripard at free-electrons.com>
> ---
>  arch/arm/dts/sunxi-u-boot.dtsi | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/arch/arm/dts/sunxi-u-boot.dtsi b/arch/arm/dts/sunxi-u-boot.dtsi
> index 5adfd9bca2ec..72e95afd780e 100644
> --- a/arch/arm/dts/sunxi-u-boot.dtsi
> +++ b/arch/arm/dts/sunxi-u-boot.dtsi
> @@ -1,5 +1,14 @@
>  #include <config.h>
>
> +/*
> + * This is the maximum size the U-Boot binary can be, which is basically
> + * the start of the environment, minus the start of the U-Boot binary in
> + * the MMC. This makes the assumption that the MMC is using 512-bytes
> + * blocks, but devices using something other than that remains to be
> + * seen.
> + */
> +#define UBOOT_MMC_MAX_SIZE	(CONFIG_ENV_OFFSET - (CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR * 512))
> +
>  / {
>  	binman {
>  		filename = "u-boot-sunxi-with-spl.bin";
> @@ -8,6 +17,9 @@
>  			filename = "spl/sunxi-spl.bin";
>  		};
>  		u-boot-img {
> +#ifdef CONFIG_MMC
> +			size = <UBOOT_MMC_MAX_SIZE>;
> +#endif
>  			pos = <CONFIG_SPL_PAD_TO>;
>  		};
>  	};
> -- 

This is broken in (at least) two ways:

1. It is simply nonsensical if u-boot and env are on different devices
   or not on mmc even if mmc support is enabled.

2. It causes u-boot-sunxi-with-spl.bin to be padded to the env offset.
   At best, this is useless.  If the env doesn't immediately follow
   u-boot, it really breaks things.

Please fix or revert, I don't really care which.

-- 
Måns Rullgård