Re: [PATCH 1/3] xz: add arch-specific tuning for alpha

[Magnus Lindholm]

Hi Matt,

On Sat, Sep 12, 2026 at 9:55 PM Matt Turner <mattst88@xxxxxxxxx> wrote:
>
> Alpha has fixed-length, 4-byte-aligned instructions and no XZ BCJ
> filter, so it wants the same LZMA2 settings as the other 4-byte-aligned
> targets. Without an entry it hits the default case, which warns
>
>   scripts/xz_wrap.sh: Arch-specific tuning is missing for 'alpha'
>
> and conservatively assumes 2-byte alignment. Alpha gains HAVE_KERNEL_XZ
> later in this series; the correct alignment also shrinks a UP1500
> kernel's XZ image from 6469320 to 6448840 bytes.
>
> Signed-off-by: Matt Turner <mattst88@xxxxxxxxx>
> ---
>  scripts/xz_wrap.sh | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/scripts/xz_wrap.sh b/scripts/xz_wrap.sh
> index f19369687030..5af0d9045cbc 100755
> --- a/scripts/xz_wrap.sh
> +++ b/scripts/xz_wrap.sh
> @@ -10,6 +10,7 @@
>  # XZ-compressed kernel isn't currently supported on every listed arch.
>  #
>  #   Arch        Align   Notes
> +#   alpha         4
>  #   arm          2/4    ARM and ARM-Thumb2
>  #   arm64         4
>  #   csky          2
> @@ -44,6 +45,10 @@ BCJ=
>  # Set the BCJ filter if one is available.
>  # It must match the #ifdef usage in lib/decompress_unxz.c.
>  case $SRCARCH in
> +       alpha)
> +               ALIGN=4
> +               ;;
> +
>         arm)
>                 if is_enabled CONFIG_THUMB2_KERNEL; then
>                         ALIGN=2
>
> --
> 2.54.0
>

I built the complete series with CONFIG_KERNEL_XZ=y  and successfully
boot-tested the resulting XZ self-extracting kernel on an UP2000+ through
SRM and aboot.

Reviewed-by: Magnus Lindholm <linmag7@xxxxxxxxx>
Tested-by: Magnus Lindholm <linmag7@xxxxxxxxx>