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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Thu, 25 Oct 2018 16:31:13 -0700
Message-ID: <CAHk-=wjHs_wff==pT=auhC4dzNYu1e+DfgN7WGWpr-Vsfv-d8w@mail.gmail.com>
Subject: Re: [v3 03/12] x86/fsgsbase/64: Add intrinsics/macros for FSGSBASE instructions
To:     luto@kernel.org
Cc:     ak@linux.intel.com, chang.seok.bae@intel.com,
        Ingo Molnar <mingo@kernel.org>, tglx@linutronix.de,
        Peter Anvin <hpa@zytor.com>, dave.hansen@linux.intel.com,
        markus.t.metzger@intel.com, ravi.v.shankar@intel.com,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Thu, Oct 25, 2018 at 4:14 PM Andy Lutomirski <luto@kernel.org> wrote:
>
> On Wed, Oct 24, 2018 at 12:21 PM Andi Kleen <ak@linux.intel.com> wrote:
> >
> > BTW the other option would be to update the min-binutils requirement
> > to 2.21 (currently it is 2.20) and then write it directly without .byte.
> > I believe 2.21 added support for these instructions.
> >
> > (It's only a binutils requirement, don't need gcc support)
>
> I'd personally be fine with this.  Linus? Thomas? Ingo?

I always vote for "require modern tools" as long as it doesn't cause problems.

binutils-2.21 is something like seven years old by now, but the real
issue would be what versions distros are actually shipping. I don't
want people to have to build their own binutils just to build a
kernel.

It's usually some ancient enterprise distro that is stuck on old
versions. Anybody have any idea?

                 Linus