linux-kernel - Re: [PATCH] x86: mtrr: cyrix: Mark expected switch fall-through

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Message-ID: <201908051319.B3B8858@keescook>
Date:   Mon, 5 Aug 2019 13:19:31 -0700
From:   Kees Cook <keescook@...omium.org>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        "x86@...nel.orgCc:linux-kernel"@vger.kernel.org
Subject: Re: [PATCH] x86: mtrr: cyrix: Mark expected switch fall-through

On Mon, Aug 05, 2019 at 03:17:12PM -0500, Gustavo A. R. Silva wrote:
> Mark switch cases where we are expecting to fall through.
> 
> Fix the following warning (Building: i386_defconfig i386):
> 
> arch/x86/kernel/cpu/mtrr/cyrix.c:99:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>

Reviewed-by: Kees Cook <keescook@...omium.org>

-Kees

> ---
>  arch/x86/kernel/cpu/mtrr/cyrix.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/x86/kernel/cpu/mtrr/cyrix.c b/arch/x86/kernel/cpu/mtrr/cyrix.c
> index 4296c702a3f7..72182809b333 100644
> --- a/arch/x86/kernel/cpu/mtrr/cyrix.c
> +++ b/arch/x86/kernel/cpu/mtrr/cyrix.c
> @@ -98,6 +98,7 @@ cyrix_get_free_region(unsigned long base, unsigned long size, int replace_reg)
>  	case 7:
>  		if (size < 0x40)
>  			break;
> +		/* Else, fall through */
>  	case 6:
>  	case 5:
>  	case 4:
> -- 
> 2.22.0
> 

-- 
Kees Cook