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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun, 29 Mar 2020 15:12:29 -0700
Message-ID: <CAHk-=wgmkAvRqOe9B6Nt3X8yFtiFHshoTU2B9tn2hvPug2Wc-Q@mail.gmail.com>
Subject: Re: [RFC][PATCH 01/22] x86 user stack frame reads: switch to explicit __get_user()
To:     Andy Lutomirski <luto@kernel.org>
Cc:     David Laight <David.Laight@aculab.com>,
        Ingo Molnar <mingo@kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Thomas Gleixner <tglx@linutronix.de>, X86 ML <x86@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Borislav Petkov <bp@alien8.de>
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On Sun, Mar 29, 2020 at 3:06 PM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> Anyway, just in case people want to see it, I'm attaching my current
> unconditional patch.

Side note: I've actually been running variations of this patch for a
couple of months now, so it's even tested, but I debugged one of the
problems with the clang asm goto support it exposed only this last
week. I thought it was a problem with my patch for the longest time,
and couldn't figure it out.

So to work it needs tip-of-tree clang *and* an additional llvm bugfix
from Nick Desaulniers for that problem I reported that hasn't landed
yet.

So I included that patch just for people to look at. If you actually
want to test it, I can send you Nick's llvm fix too, and you need to
have the ability to build your own clang.

                 Linus