linux-kernel - Re: [PATCH v2 00/10] x86: Clean up percpu operations

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Date:   Wed, 8 Jul 2020 12:36:18 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
        "H . Peter Anvin" <hpa@...or.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Brian Gerst <brgerst@...il.com>,
        Dmitry Golovin <dima@...ovin.in>,
        Alistair Delva <adelva@...gle.com>
Subject: Re: [PATCH v2 00/10] x86: Clean up percpu operations

On Mon, Jun 1, 2020 at 2:00 PM Nick Desaulniers <ndesaulniers@...gle.com> wrote:
>
> On Sat, May 30, 2020 at 3:11 PM Brian Gerst <brgerst@...il.com> wrote:
> >
> > The core percpu operations already have a switch on the width of the
> > data type, which resulted in an extra amount of dead code being
> > generated with the x86 operations having another switch.  This patch set
> > rewrites the x86 ops to remove the switch.  Additional cleanups are to
> > use named assembly operands, and to cast variables to the width used in
> > the assembly to make Clang happy.
>
> Thanks for all of the work that went into this series.  I think I've
> reviewed all of them.
> With this series plus this hunk:
> https://github.com/ClangBuiltLinux/continuous-integration/blob/master/patches/llvm-all/linux-next/x86/x86-support-i386-with-Clang.patch#L219-L237
> I can build and boot i386_defconfig with Clang! So for the series:
>
> Reviewed-by: Nick Desaulniers <ndesaulniers@...gle.com>
> Tested-by: Nick Desaulniers <ndesaulniers@...gle.com>

tglx, Ingo, Boris, Linus,
Do you all have thoughts on this series?  I can understand "let
sleeping dogs lie" but some Android folks are really interested in
i386 testing, and randconfigs/allnoconfigs are doing i386 builds which
are currently broken w/ Clang. This series gets us closer to having
test coverage of this ISA with another toolchain, FWIW.

-- 
Thanks,
~Nick Desaulniers