linux-kernel - Re: [RFC V3 11/18] arm64: alternative: Mark .altinstr_replacement as containing executable instructions

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Message-ID: <20190701145104.GE21774@arrakis.emea.arm.com>
Date:   Mon, 1 Jul 2019 15:51:04 +0100
From:   Catalin Marinas <catalin.marinas@....com>
To:     Raphael Gault <raphael.gault@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        jpoimboe@...hat.com, peterz@...radead.org, will.deacon@....com,
        julien.thierry@....com
Subject: Re: [RFC V3 11/18] arm64: alternative: Mark .altinstr_replacement as
 containing executable instructions

On Mon, Jun 24, 2019 at 10:55:41AM +0100, Raphael Gault wrote:
> Until now, the section .altinstr_replacement wasn't marked as containing
> executable instructions on arm64. This patch changes that so that it is
> coherent with what is done on x86.
> 
> Signed-off-by: Raphael Gault <raphael.gault@....com>
> ---
>  arch/arm64/include/asm/alternative.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h
> index b9f8d787eea9..e9e6b81e3eb4 100644
> --- a/arch/arm64/include/asm/alternative.h
> +++ b/arch/arm64/include/asm/alternative.h
> @@ -71,7 +71,7 @@ static inline void apply_alternatives_module(void *start, size_t length) { }
>  	ALTINSTR_ENTRY(feature,cb)					\
>  	".popsection\n"							\
>  	" .if " __stringify(cb) " == 0\n"				\
> -	".pushsection .altinstr_replacement, \"a\"\n"			\
> +	".pushsection .altinstr_replacement, \"ax\"\n"			\
>  	"663:\n\t"							\
>  	newinstr "\n"							\
>  	"664:\n\t"							\

I guess that's an inconsistency we missed since the asm macro has "ax".

-- 
Catalin