[PATCH] riscv: Fix an off-by-one in get_early_cmdline()

[Alexandre Ghiti]

Hi Christophe,

On 29/10/2023 08:20, Christophe JAILLET wrote:
> The ending NULL is not taken into account by strncat(), so switch to
> strlcat() to correctly compute the size of the available memory when
> appending CONFIG_CMDLINE to 'early_cmdline'.
>
> Fixes: 26e7aacb83df ("riscv: Allow to downgrade paging mode from the command line")
> Signed-off-by: Christophe JAILLET <christophe.jaillet at wanadoo.fr>
> ---
>   arch/riscv/kernel/pi/cmdline_early.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/arch/riscv/kernel/pi/cmdline_early.c b/arch/riscv/kernel/pi/cmdline_early.c
> index 68e786c84c94..f6d4dedffb84 100644
> --- a/arch/riscv/kernel/pi/cmdline_early.c
> +++ b/arch/riscv/kernel/pi/cmdline_early.c
> @@ -38,8 +38,7 @@ static char *get_early_cmdline(uintptr_t dtb_pa)
>   	if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
>   	    IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
>   	    fdt_cmdline_size == 0 /* CONFIG_CMDLINE_FALLBACK */) {
> -		strncat(early_cmdline, CONFIG_CMDLINE,
> -			COMMAND_LINE_SIZE - fdt_cmdline_size);
> +		strlcat(early_cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
>   	}
>   
>   	return early_cmdline;

This looks good to me, you can add:

Reviewed-by: Alexandre Ghiti <alexghiti at rivosinc.com>

Thanks,

Alex