Re: [ImageBuilder PATCH v3] uboot-script-gen: use size from arm64 Image header

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 13 Sep 2023, Stewart Hildebrand wrote:
> There is a corner case where the filesizes of the xen and Linux kernel images
> are not sufficient. These binaries likely contain NOLOAD sections (e.g. bss),
> which are not accounted in the filesize.
> 
> Check for the presence of an arm64 kernel image header, and get the effective
> image size from the header. Use the effective image size for calculating the
> next load address and for populating the size in the /chosen/dom*/reg 
> property.
> 
> Signed-off-by: Stewart Hildebrand <stewart.hildebrand@xxxxxxx>
> Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> v2->v3:
> * simplify awk parsing
> * add R-b
> 
> v1->v2:
> * add in-code comments
> * use variables more
> ---
>  scripts/uboot-script-gen | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/uboot-script-gen b/scripts/uboot-script-gen
> index 9656a458ac00..b284887f065e 100755
> --- a/scripts/uboot-script-gen
> +++ b/scripts/uboot-script-gen
> @@ -2,7 +2,7 @@
>  
>  offset=$((2*1024*1024))
>  filesize=0
> -prog_req=(mkimage file fdtput mktemp awk)
> +prog_req=(mkimage file fdtput mktemp awk od)
>  
>  function cleanup_and_return_err()
>  {
> @@ -435,6 +435,21 @@ function add_size()
>  {
>      local filename=$1
>      local size=`stat -L --printf="%s" $filename`
> +    # Read arm64 header magic 
> (https://www.kernel.org/doc/Documentation/arm64/booting.txt)
> +    local arm64_header_magic=$(od -j 56 -N 4 -t x4 ${filename} | awk 'NR==1 
> {print $2}')
> +
> +    # Check for valid arm64 header magic value 0x644d5241
> +    if [ "${arm64_header_magic}" = "644d5241" ]
> +    then
> +        # Read effective size, which may be larger than the filesize due to 
> noload sections, e.g. bss
> +        local arm64_header_size=$(od -j 16 -N 8 -t u8 ${filename} | awk 
> 'NR==1 {print $2}')
> +
> +        if [ "${arm64_header_size}" -gt "${size}" ]
> +        then
> +            size=${arm64_header_size}
> +        fi
> +    fi
> +
>      memaddr=$(( $memaddr + $size + $offset - 1))
>      memaddr=$(( $memaddr & ~($offset - 1) ))
>      memaddr=`printf "0x%X\n" $memaddr`
> -- 
> 2.42.0
>