linux-kernel - Re: [PATCH] ARM: kexec: drop invalid assembly argument

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Date:   Wed, 5 Feb 2020 23:54:40 +0000
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Stefan Agner <stefan@...er.ch>
Cc:     clang-built-linux@...glegroups.com, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] ARM: kexec: drop invalid assembly argument

On Wed, Feb 05, 2020 at 11:59:26PM +0100, Stefan Agner wrote:
> The tst menomic has only a single #<const> argument in Thumb mode. There
> is an ARM variant which allows to write #<const> as #<byte>, #<rot>
> which probably is where the current syntax comes from.
> 
> It seems that binutils does not care about the additional parameter.
> Clang however complains in Thumb2 mode:
> arch/arm/kernel/relocate_kernel.S:28:12: error: too many operands for
> instruction
>  tst r3,#1,0
>            ^
> 
> Drop the unnecessary parameter. This fixes building this file in Thumb2
> mode with the Clang integrated assembler.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/770
> Signed-off-by: Stefan Agner <stefan@...er.ch>

Please drop it in the patch system, thanks.

> ---
>  arch/arm/kernel/relocate_kernel.S | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm/kernel/relocate_kernel.S b/arch/arm/kernel/relocate_kernel.S
> index 7eaa2ae7aff5..72a08786e16e 100644
> --- a/arch/arm/kernel/relocate_kernel.S
> +++ b/arch/arm/kernel/relocate_kernel.S
> @@ -25,26 +25,26 @@ ENTRY(relocate_new_kernel)
>  	ldr	r3, [r0],#4
>  
>  	/* Is it a destination page. Put destination address to r4 */
> -	tst	r3,#1,0
> +	tst	r3,#1
>  	beq	1f
>  	bic	r4,r3,#1
>  	b	0b
>  1:
>  	/* Is it an indirection page */
> -	tst	r3,#2,0
> +	tst	r3,#2
>  	beq	1f
>  	bic	r0,r3,#2
>  	b	0b
>  1:
>  
>  	/* are we done ? */
> -	tst	r3,#4,0
> +	tst	r3,#4
>  	beq	1f
>  	b	2f
>  
>  1:
>  	/* is it source ? */
> -	tst	r3,#8,0
> +	tst	r3,#8
>  	beq	0b
>  	bic r3,r3,#8
>  	mov r6,#1024
> -- 
> 2.25.0
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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