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Date: Thu, 11 Jan 2018 17:58:07 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>, x86@kernel.org,
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        Andy Lutomirski <luto@amacapital.net>,
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Subject: Re: [PATCH 2/3] objtool: Ignore retpoline alternatives
Message-ID: <20180111165807.GF6176@hirez.programming.kicks-ass.net>
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On Thu, Jan 11, 2018 at 10:48:26AM -0600, Josh Poimboeuf wrote:
> I think I heard that retpolines won't be ported to anything older than
> GCC 4.9, so maybe it's safe to use '%='.  I don't remember when it was
> introduced into GCC though.

root@interlagos:~/tmp# gcc-4.8 -o test test.c
root@interlagos:~/tmp# ./test
11

--- test.c

#include <stdio.h>

void main(void)
{
        int val;

        asm ("mov $(%=),%0" : "=A" (val));

        printf("%d\n", val);
}