Re: [PATCH] ARM: Allow for kernel command line concatenation

[Nicolas Pitre]

On Thu, 7 Apr 2011, oskar.andero@xxxxxxxxxxxxxxxx wrote:

> From: Victor Boivie <victor.boivie@xxxxxxxxxxxxxxxx>
> 
> This patch allows the provided CONFIG_CMDLINE to be concatenated
> with the one provided by the boot loader. This is useful to
> merge the static values defined in CONFIG_CMDLINE with the
> boot loader's (possibly) more dynamic values, such as startup
> reasons and more.
> 
> Signed-off-by: Victor Boivie <victor.boivie@xxxxxxxxxxxxxxxx>
> Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxxxx>
> Signed-off-by: Oskar Andero <oskar.andero@xxxxxxxxxxxxxxxx>

Acked-by: Nicolas Pitre <nicolas.pitre@xxxxxxxxxx>

> ---
>  arch/arm/Kconfig        |   21 ++++++++++++++++++---
>  arch/arm/kernel/setup.c |   13 +++++++++----
>  2 files changed, 27 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 5b9f78b..fe34ed7 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1743,16 +1743,31 @@ config CMDLINE
>  	  time by entering them here. As a minimum, you should specify the
>  	  memory size and the root device (e.g., mem=64M root=/dev/nfs).
>  
> +choice
> +	prompt "Kernel command line type" if CMDLINE != ""
> +	default CMDLINE_FROM_BOOTLOADER
> +
> +config CMDLINE_FROM_BOOTLOADER
> +	bool "Use bootloader kernel arguments if available"
> +	help
> +	  Uses the command-line options passed by the boot loader. If
> +	  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"
> -	depends on CMDLINE != ""
>  	help
>  	  Always use the default kernel command string, even if the boot
>  	  loader passes other arguments to the kernel.
>  	  This is useful if you cannot or don't want to change the
>  	  command-line options your boot loader passes to the kernel.
> -
> -	  If unsure, say N.
> +endchoice
>  
>  config XIP_KERNEL
>  	bool "Kernel Execute-In-Place from ROM"
> diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> index 006c1e8..6dce209 100644
> --- a/arch/arm/kernel/setup.c
> +++ b/arch/arm/kernel/setup.c
> @@ -672,11 +672,16 @@ __tagtable(ATAG_REVISION, parse_tag_revision);
>  
>  static int __init parse_tag_cmdline(const struct tag *tag)
>  {
> -#ifndef CONFIG_CMDLINE_FORCE
> -	strlcpy(default_command_line, tag->u.cmdline.cmdline, COMMAND_LINE_SIZE);
> -#else
> +#if defined(CONFIG_CMDLINE_EXTEND)
> +	strlcat(default_command_line, " ", COMMAND_LINE_SIZE);
> +	strlcat(default_command_line, tag->u.cmdline.cmdline,
> +		COMMAND_LINE_SIZE);
> +#elif defined(CONFIG_CMDLINE_FORCE)
>  	pr_warning("Ignoring tag cmdline (using the default kernel command line)\n");
> -#endif /* CONFIG_CMDLINE_FORCE */
> +#else
> +	strlcpy(default_command_line, tag->u.cmdline.cmdline,
> +		COMMAND_LINE_SIZE);
> +#endif
>  	return 0;
>  }
>  
> -- 
> 1.7.4.2
> 
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