Re: [PATCH] LoongArch: Change COMMAND_LINE_SIZE to 4096

[Chenghao Duan <duanchenghao@kylinos.cn>]

On Mon, Sep 22, 2025 at 10:10:57AM +0800, Chenghao Duan wrote:
> The default COMMAND_LINE_SIZE inherited from asm-generic is 512, which
> is too small for modern use cases. For example, when the parameter path
> in the cmdline of the kdump first kernel is too long, the limit is
> easily exceeded when loading the second kernel.
> 
> Increase the command line size to 4096 bytes, In LoongArch, this is
> consistent with the upstream configuration of the Linux kernel.
> linux kernel commit: f7794a4d92ade518c813de69a01b27ca6d8d86f3.

I'm very sorry, but the commit ID in the previous email was incorrect.
linux kernel commit: f7794a4d92ad(LoongArch: Increase COMMAND_LINE_SIZE up to 4096).

> 
> This patch is necessary because the Linux kernel has been changed to
> 4096. When the kernel cmdline size exceeds 512, the --reuse-cmdline
> option of the kexec command will inevitably result in an error.
> 
> The COMMAND_LINE_SIZE in kexec/arch/loongarch/crashdump-loongarch.h
> is unused, so it is removed here.
> 
> Suggested-by: Youling Tang <tangyouling@kylinos.cn>
> Signed-off-by: Chenghao Duan <duanchenghao@kylinos.cn>
> ---
>  kexec/arch/loongarch/crashdump-loongarch.h | 2 --
>  kexec/arch/loongarch/kexec-loongarch.h     | 2 +-
>  2 files changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/kexec/arch/loongarch/crashdump-loongarch.h b/kexec/arch/loongarch/crashdump-loongarch.h
> index 25ff24b..dac9e71 100644
> --- a/kexec/arch/loongarch/crashdump-loongarch.h
> +++ b/kexec/arch/loongarch/crashdump-loongarch.h
> @@ -20,7 +20,5 @@ int get_crash_kernel_load_range(uint64_t *start, uint64_t *end);
>  /* crash dump kernel support at most two regions, low_region and high region. */
>  #define CRASH_MAX_RESERVED_RANGES      2
>  
> -#define COMMAND_LINE_SIZE	512
> -
>  extern struct arch_options_t arch_options;
>  #endif /* CRASHDUMP_LOONGARCH_H */
> diff --git a/kexec/arch/loongarch/kexec-loongarch.h b/kexec/arch/loongarch/kexec-loongarch.h
> index 2c7624f..0bd462f 100644
> --- a/kexec/arch/loongarch/kexec-loongarch.h
> +++ b/kexec/arch/loongarch/kexec-loongarch.h
> @@ -13,7 +13,7 @@
>  
>  #define CORE_TYPE_ELF64 1
>  
> -#define COMMAND_LINE_SIZE 512
> +#define COMMAND_LINE_SIZE 4096
>  
>  #define KiB(x) ((x) * 1024UL)
>  #define MiB(x) (KiB(x) * 1024UL)
> -- 
> 2.25.1