Subject: Re: [PATCH] module: set .init_array alignment to 8
To: David Daney <david.daney@cavium.com>, Jessica Yu <jeyu@redhat.com>,
        Rusty Russell <rusty@rustcorp.com.au>, <linux-kernel@vger.kernel.org>
References: <20170308013108.13345-1-david.daney@cavium.com>
CC: Andrew Morton <akpm@linux-foundation.org>
From: Andrey Ryabinin <aryabinin@virtuozzo.com>
Message-ID: <e30975ba-0e5b-218f-0edf-04377d55e7b2@virtuozzo.com>
Date: Thu, 9 Mar 2017 17:26:03 +0300
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On 03/08/2017 04:31 AM, David Daney wrote:
> The proper idiom for aligning linker sections in modules is different
> than for built-in sections.  ". = ALIGN();" followed by a forced
> output address of 0 does nothing, as forcing the address changes the
> value of ".".
> 
> Use output section alignment specifier instead.
> 
> Fixes: 9ddf82521c86 ("kernel: add support for .init_array.* constructors")
> Signed-off-by: David Daney <david.daney@cavium.com>

Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>

> ---
> 
> I noticed this when doing the __jump_table thing.  Doesn't seem to
> break a defconfig build, but otherwise untested.
> 
>  scripts/module-common.lds | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/scripts/module-common.lds b/scripts/module-common.lds
> index 9b6e246..d61b9e8 100644
> --- a/scripts/module-common.lds
> +++ b/scripts/module-common.lds
> @@ -20,8 +20,7 @@ SECTIONS {
>  	__kcrctab_unused_gpl	0 : { *(SORT(___kcrctab_unused_gpl+*)) }
>  	__kcrctab_gpl_future	0 : { *(SORT(___kcrctab_gpl_future+*)) }
>  
> -	. = ALIGN(8);
> -	.init_array		0 : { *(SORT(.init_array.*)) *(.init_array) }
> +	.init_array		0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) }
>  
>  	__jump_table		0 : ALIGN(8) { KEEP(*(__jump_table)) }
>  }
>