[PATCH] arm64: Support CMDLINE_EXTEND

[Mark Rutland]

On Tue, Mar 21, 2023 at 10:14:51AM +1300, Chris Packham wrote:
> Support extending the bootloader provided command line for arm64
> targets. This support is already present via generic DT/EFI code the
> only thing required is for the architecture to make it selectable.
> 
> Signed-off-by: Chris Packham <chris.packham at alliedtelesis.co.nz>

We deliberately dropped support for CMDLINE_EXTEND in commit:

  cae118b6acc3 ("arm64: Drop support for CMDLINE_EXTEND")

... which was mentioned the last time somone tried to re-add it:

  https://lore.kernel.org/linux-arm-kernel/ZAh8dWvbNkVQT11C@arm.com/

Has something changes such that those issues no longer apply? If so, please
call that out explicitly in the commit message. If not, I do not think we
should take this patch.

Thanks,
Mark.

> ---
>  arch/arm64/Kconfig | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 1023e896d46b..3c837b085f21 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -2228,6 +2228,12 @@ config CMDLINE_FROM_BOOTLOADER
>  	  the boot loader doesn't provide any, the default kernel command
>  	  string provided in CMDLINE will be used.
>  
> +config CMDLINE_EXTEND
> +	bool "Extend bootloader kernel arguments"
> +	help
> +	  The command-line arguments provided by the boot loader will be
> +	  appended to the default kernel command string.
> +
>  config CMDLINE_FORCE
>  	bool "Always use the default kernel command string"
>  	help
> -- 
> 2.40.0
>