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

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Date:   Mon, 1 Jun 2020 14:00:51 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Brian Gerst <brgerst@...il.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Dmitry Golovin <dima@...ovin.in>
Subject: Re: [PATCH v2 00/10] x86: Clean up percpu operations

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>

>
> Changes from v1:
> - Add separate patch for XADD constraint fix
> - Fixed sparse truncation warning
> - Add cleanup of percpu_stable_op()
> - Add patch to Remove PER_CPU()
>
> Brian Gerst (10):
>   x86/percpu: Introduce size abstraction macros
>   x86/percpu: Clean up percpu_to_op()
>   x86/percpu: Clean up percpu_from_op()
>   x86/percpu: Clean up percpu_add_op()
>   x86/percpu: Remove "e" constraint from XADD
>   x86/percpu: Clean up percpu_add_return_op()
>   x86/percpu: Clean up percpu_xchg_op()
>   x86/percpu: Clean up percpu_cmpxchg_op()
>   x86/percpu: Clean up percpu_stable_op()
>   x86/percpu: Remove unused PER_CPU() macro
>
>  arch/x86/include/asm/percpu.h | 510 ++++++++++++----------------------
>  1 file changed, 172 insertions(+), 338 deletions(-)
>
>
> base-commit: 229aaa8c059f2c908e0561453509f996f2b2d5c4
> --
> 2.25.4
>


-- 
Thanks,
~Nick Desaulniers