linux-kernel - Re: [RFC v4 01/18] objtool: Add abstraction for computation of symbols offsets

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Message-ID: <20190822195722.gx36v32x2zfythwy@treble>
Date:   Thu, 22 Aug 2019 14:57:22 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Raphael Gault <raphael.gault@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        peterz@...radead.org, catalin.marinas@....com, will.deacon@....com,
        julien.thierry.kdev@...il.com, raph.gault+kdev@...il.com
Subject: Re: [RFC v4 01/18] objtool: Add abstraction for computation of
 symbols offsets

On Fri, Aug 16, 2019 at 01:23:46PM +0100, Raphael Gault wrote:
> @@ -672,14 +672,19 @@ static int add_call_destinations(struct objtool_file *file)
>  			}
>  
>  		} else if (rela->sym->type == STT_SECTION) {
> +			/*
> +			 * the original x86_64 code adds 4 to the rela->addend
> +			 * which is not needed on arm64 architecture.
> +			 */
> +			dest_off = arch_dest_rela_offset(rela->addend);

I agree with Julien that this comment isn't needed.  The "arch_" prefix
already implies there are arch-specific differences.

Also, this patch should replace all the other "addend + 4" usages:

$ git grep "addend + 4" tools/objtool
tools/objtool/arch/x86/decode.c:        return addend + 4;
tools/objtool/check.c:                  dest_off = rela->addend + 4;
tools/objtool/check.c:                  dest_off = rela->sym->sym.st_value + rela->addend + 4;

-- 
Josh