linux-kernel - Re: [PATCH v2 11/12] retpoline/objtool: Disable some objtool warnings

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Message-ID: <20180104160601.w2l2wdabuxa26xzq@treble>
Date:   Thu, 4 Jan 2018 10:06:01 -0600
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Andi Kleen <ak@...ux.intel.com>
Cc:     Andi Kleen <andi@...stfloor.org>, tglx@...utronix.de,
        torvalds@...ux-foundation.org, gregkh@...ux-foundation.org,
        linux-kernel@...r.kernel.org, tim.c.chen@...ux.intel.com
Subject: Re: [PATCH v2 11/12] retpoline/objtool: Disable some objtool warnings

On Thu, Jan 04, 2018 at 07:59:14AM -0800, Andi Kleen wrote:
> > NAK.  We can't blindly disable objtool warnings, that will break
> > livepatch and the ORC unwinder.  If you share a .o file (or the GCC
> > code) I can look at adding retpoline support.
> 
> I don't think we can wait for that. We can disable livepatch and the
> unwinder for now. They are not essential. Frame pointers should work
> well enough for unwinding

If you want to make this feature conflict with livepatch and ORC,
silencing objtool warnings is not the way to do it.

> and afaik nobody can use livepatch in mainline anyways.

Why not?  The patch creation tooling is still out-of-tree, but livepatch
itself is fully supported in mainline.

-- 
Josh