Date: Tue, 9 Jan 2018 13:36:31 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
        David Woodhouse <dwmw@amazon.co.uk>,
        Andi Kleen <ak@linux.intel.com>, Paul Turner <pjt@google.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linux-foundation.org>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Kees Cook <keescook@google.com>,
        Rik van Riel <riel@redhat.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Jiri Kosina <jikos@kernel.org>, gnomes@lxorguk.ukuu.org.uk
Subject: Re: [PATCH v6 01/10] x86/retpoline: Add initial retpoline support
Message-ID: <20180109123631.GH6176@hirez.programming.kicks-ass.net>
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On Mon, Jan 08, 2018 at 02:46:32PM +0100, Thomas Gleixner wrote:
> On Mon, 8 Jan 2018, Josh Poimboeuf wrote:

> > I wonder if an error might be more appropriate than a warning.  I
> > learned from experience that a lot of people don't see these Makefile
> > warnings, and this would be a dangerous one to miss.
> > 
> > Also if this were an error, you could get rid of the RETPOLINE define,
> > and that would be one less define cluttering up the already way-too-long
> > GCC arg list.
> 
> It still allows to get the ASM part covered. If that's worth it I can't tell.

So elsewhere you stated we're dropping support for GCC without asm-goto
(<4.5), does it then make sense to make one more step and mandate a
retpoline capable compiler, which would put us at >=4.9 (for x86).

That would get rid of this weird case as well.