linux-kernel - Re: [PATCH v2 1/6] bus: arm-cci: use asm unreachable

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Date:   Mon, 16 Apr 2018 17:59:10 +0200
From:   Stefan Agner <stefan@...er.ch>
To:     arnd@...db.de
Cc:     robin.murphy@....com, nicolas.pitre@...aro.org,
        marc.zyngier@....com, behanw@...verseincode.com,
        keescook@...omium.org, Bernhard.Rosenkranzer@...aro.org,
        mka@...omium.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, linux@...linux.org.uk,
        ard.biesheuvel@...aro.org
Subject: Re: [PATCH v2 1/6] bus: arm-cci: use asm unreachable

On 25.03.2018 20:09, Stefan Agner wrote:
> Mixing asm and C code is not recommended in a naked function by
> gcc and leads to an error when using clang:
>   drivers/bus/arm-cci.c:2107:2: error: non-ASM statement in naked
>   function is not supported
>         unreachable();
>         ^
> 
> While the function is marked __naked it actually properly return
> in asm. There is no need for the unreachable() call.

Hi Arnd,

I think previously changes to this driver went through one of your
trees, can you pick this up?

--
Stefan


> 
> Suggested-by: Russell King <linux@....linux.org.uk>
> Signed-off-by: Stefan Agner <stefan@...er.ch>
> ---
> Changes in v2:
> - Don't add assembly ASM_UNREACHABLE, just drop unreachable()
> 
>  drivers/bus/arm-cci.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
> index 5426c04fe24b..fc2da3a617ac 100644
> --- a/drivers/bus/arm-cci.c
> +++ b/drivers/bus/arm-cci.c
> @@ -2103,8 +2103,6 @@ asmlinkage void __naked cci_enable_port_for_self(void)
>  	[sizeof_struct_cpu_port] "i" (sizeof(struct cpu_port)),
>  	[sizeof_struct_ace_port] "i" (sizeof(struct cci_ace_port)),
>  	[offsetof_port_phys] "i" (offsetof(struct cci_ace_port, phys)) );
> -
> -	unreachable();
>  }
>  
>  /**