Re: [PATCH v6 01/10] x86/retpoline: Add initial retpoline support

[Peter Zijlstra]

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.