Re: [PATCH] kbuild: Enable armthumb BCJ filter for Thumb-2 kernel

From: Jubin Zhong
Date: Fri Nov 19 2021 - 22:18:53 EST


> If a Thumb-2 kernel will always use the ARM-Thumb BCJ filter, one can
> save a few bytes from the pre-boot code by omitting the ARM BCJ filter:
>
> --- a/lib/decompress_unxz.c
> +++ b/lib/decompress_unxz.c
> @@ -129,7 +129,11 @@
> # define XZ_DEC_POWERPC
> #endif
> #ifdef CONFIG_ARM
> -# define XZ_DEC_ARM
> +# ifdef CONFIG_THUMB2_KERNEL
> +# define XZ_DEC_ARMTHUMB
> +# else
> +# define XZ_DEC_ARM
> +# endif
> #endif
> #ifdef CONFIG_IA64
> # define XZ_DEC_IA64
>
>> --- a/scripts/xz_wrap.sh
>> +++ b/scripts/xz_wrap.sh
>> @@ -8,6 +8,7 @@
>> # This file has been put into the public domain.
>> # You can do whatever you want with this file.
>> #
>> +. include/config/auto.conf
>
> I suggest adding an empty line before this new line so that it is
> clearly separated from the header comment.
>
>> +if [ -n "${CONFIG_THUMB2_KERNEL}" ];then
>
> I suggest adding a space after the semi-colon: ]; then
>
> With or without the above modifications:

Thanks for your advices. I will incorporate the above modifications and send patch v2.