linux-kernel - Re: [PATCH v8 2/5] x86: Add cmdline

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Date:   Mon, 14 Nov 2022 15:28:55 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Evgeniy Baskov <baskov@...ras.ru>
Cc:     Dave Hansen <dave.hansen@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org, x86@...nel.org,
        Alexey Khoroshilov <khoroshilov@...ras.ru>
Subject: Re: [PATCH v8 2/5] x86: Add cmdline_prepare() helper

On Thu, Nov 10, 2022 at 04:09:30PM +0300, Evgeniy Baskov wrote:
> Command line needs to be combined in both compressed and uncompressed
> kernel from built-in and boot command line strings, which requires
> non-trivial logic depending on CONFIG_CMDLINE_BOOL and
> CONFIG_CMDLINE_OVERRIDE.
> 
> Add a helper function to avoid code duplication.
> 
> Signed-off-by: Evgeniy Baskov <baskov@...ras.ru>
> ---
>  arch/x86/include/asm/shared/cmdline.h | 35 +++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
>  create mode 100644 arch/x86/include/asm/shared/cmdline.h
> 
> diff --git a/arch/x86/include/asm/shared/cmdline.h b/arch/x86/include/asm/shared/cmdline.h
> new file mode 100644
> index 000000000000..01736d66028d
> --- /dev/null
> +++ b/arch/x86/include/asm/shared/cmdline.h
> @@ -0,0 +1,35 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef _ASM_X86_SETUP_CMDLINE_H
> +#define _ASM_X86_SETUP_CMDLINE_H
> +
> +#define _SETUP
> +#include <asm/setup.h> /* For COMMAND_LINE_SIZE */
> +#undef _SETUP
> +
> +#include <linux/string.h>
> +
> +#ifdef CONFIG_CMDLINE_BOOL
> +#define BUILTIN_COMMAND_LINE CONFIG_CMDLINE
> +#else
> +#define BUILTIN_COMMAND_LINE ""
> +#endif
> +
> +static inline void cmdline_prepare(char *dst, const char *boot_command_line)
> +{
> +	if (!IS_ENABLED(CONFIG_CMDLINE_BOOL)) {
> +		strscpy(dst, boot_command_line, COMMAND_LINE_SIZE);
> +	} else {
> +		strscpy(dst, BUILTIN_COMMAND_LINE, COMMAND_LINE_SIZE);
> +		/*
> +		 * Append boot loader cmdline to builtin, if it exists
> +		 * and should not be overriden.
> +		 */
> +		if (!IS_ENABLED(CONFIG_CMDLINE_OVERRIDE) && boot_command_line[0]) {
> +			strlcat(dst, " ", COMMAND_LINE_SIZE);
> +			strlcat(dst, boot_command_line, COMMAND_LINE_SIZE);
> +		}

You keep changing what I'm suggesting and the next patch has a strscpy()
outside of the function.

When I say it should be all concentrated in one function, I really mean
it.

So now it is my turn: I'll do it how I think it should be done and you
can review it.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette