[PATCH] arm64: Kconfig: add CONFIG_CMDLINE_EXTEND

[PATCH] arm64: Kconfig: add CONFIG_CMDLINE_EXTEND

[Paul Cercueil]

Other archs have it, and it is supported in arch-independent code, so I
see no reason why it is not provided on Aarch64. Add it there.

Signed-off-by: Paul Cercueil <paul.cercueil@bootlin.com>
---
 arch/arm64/Kconfig | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1075bc661833..f8542e532b50 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -2551,6 +2551,12 @@ 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
-- 
2.47.3

Re: [PATCH] arm64: Kconfig: add CONFIG_CMDLINE_EXTEND

[Will Deacon]

On Tue, Nov 03, 2026 at 09:41:40AM +0100, Paul Cercueil wrote:
> Other archs have it, and it is supported in arch-independent code, so I
> see no reason why it is not provided on Aarch64. Add it there.
> 
> Signed-off-by: Paul Cercueil <paul.cercueil@bootlin.com>
> ---
>  arch/arm64/Kconfig | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 1075bc661833..f8542e532b50 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -2551,6 +2551,12 @@ 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.

We previously reverted this in cae118b6acc3 ("arm64: Drop support for
CMDLINE_EXTEND") and I think that reasoning still applies. The thing
that _has_ changed since then, is that I think bootconfig now has some
support for early params, so that's really what people should be using
here.

Will

Re: [PATCH] arm64: Kconfig: add CONFIG_CMDLINE_EXTEND

[Paul Cercueil]

Hi Will,

Le mardi 03 novembre 2026 à 11:17 +0000, Will Deacon a écrit :
> On Tue, Nov 03, 2026 at 09:41:40AM +0100, Paul Cercueil wrote:
> > Other archs have it, and it is supported in arch-independent code, so I
> > see no reason why it is not provided on Aarch64. Add it there.
> > 
> > Signed-off-by: Paul Cercueil <paul.cercueil@bootlin.com>
> > ---
> >  arch/arm64/Kconfig | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index 1075bc661833..f8542e532b50 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -2551,6 +2551,12 @@ 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.
> 
> We previously reverted this in cae118b6acc3 ("arm64: Drop support for
> CMDLINE_EXTEND") and I think that reasoning still applies. The thing
> that _has_ changed since then, is that I think bootconfig now has some
> support for early params, so that's really what people should be using
> here.

I didn't know about bootconfig, that looks like exactly what I need, thanks!

Cheers,
-Paul

Re: [PATCH] arm64: Kconfig: add CONFIG_CMDLINE_EXTEND

[Will Deacon]

[+Breno & Masami]

On Tue, Nov 03, 2026 at 12:49:21PM +0100, Paul Cercueil wrote:
> Le mardi 03 novembre 2026 à 11:17 +0000, Will Deacon a écrit :
> > On Tue, Nov 03, 2026 at 09:41:40AM +0100, Paul Cercueil wrote:
> > > Other archs have it, and it is supported in arch-independent code, so I
> > > see no reason why it is not provided on Aarch64. Add it there.
> > > 
> > > Signed-off-by: Paul Cercueil <paul.cercueil@bootlin.com>
> > > ---
> > >  arch/arm64/Kconfig | 6 ++++++
> > >  1 file changed, 6 insertions(+)
> > > 
> > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > > index 1075bc661833..f8542e532b50 100644
> > > --- a/arch/arm64/Kconfig
> > > +++ b/arch/arm64/Kconfig
> > > @@ -2551,6 +2551,12 @@ 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.
> > 
> > We previously reverted this in cae118b6acc3 ("arm64: Drop support for
> > CMDLINE_EXTEND") and I think that reasoning still applies. The thing
> > that _has_ changed since then, is that I think bootconfig now has some
> > support for early params, so that's really what people should be using
> > here.
> 
> I didn't know about bootconfig, that looks like exactly what I need, thanks!

Great! Just watch out for the early_param support. Historically,
bootconfig silently dropped early parameters, so it was quite limited in
what you could use it for. However, I think Breno and Masami have recently
fixed that but I'm not entirely sure. I wanted to attend the recent LPC
session about it, but I had a conflict and haven't had chance to dig up
the recording.

Will