linux-kernel - Re: [PATCH] kbuild, x86: revert macros in extended asm workarounds

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Message-ID: <20181213105146.GH5289@hirez.programming.kicks-ass.net>
Date:   Thu, 13 Dec 2018 11:51:46 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Richard Biener <rguenther@...e.de>,
        Nadav Amit <namit@...are.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Sedat Dilek <sedat.dilek@...il.com>,
        Segher Boessenkool <segher@...nel.crashing.org>,
        linux-arch@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        Luc Van Oostenryck <luc.vanoostenryck@...il.com>,
        linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org,
        Michal Marek <michal.lkml@...kovi.net>,
        linux-sparse@...r.kernel.org, Alok Kataria <akataria@...are.com>,
        Juergen Gross <jgross@...e.com>,
        Andy Lutomirski <luto@...nel.org>, linux-kbuild@...r.kernel.org
Subject: Re: [PATCH] kbuild, x86: revert macros in extended asm workarounds

On Thu, Dec 13, 2018 at 06:17:41PM +0900, Masahiro Yamada wrote:
> Revert the following commits:
> 
> - 5bdcd510c2ac9efaf55c4cbd8d46421d8e2320cd
>   ("x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs")
> 
> - d5a581d84ae6b8a4a740464b80d8d9cf1e7947b2
>   ("x86/cpufeature: Macrofy inline assembly code to work around GCC inlining bugs")
> 
> - 0474d5d9d2f7f3b11262f7bf87d0e7314ead9200.
>   ("x86/extable: Macrofy inline assembly code to work around GCC inlining bugs")
> 
> - 494b5168f2de009eb80f198f668da374295098dd.
>   ("x86/paravirt: Work around GCC inlining bugs when compiling paravirt ops")
> 
> - f81f8ad56fd1c7b99b2ed1c314527f7d9ac447c6.
>   ("x86/bug: Macrofy the BUG table section handling, to work around GCC inlining bugs")
> 
> - 77f48ec28e4ccff94d2e5f4260a83ac27a7f3099.
>   ("x86/alternatives: Macrofy lock prefixes to work around GCC inlining bugs")
> 
> - 9e1725b410594911cc5981b6c7b4cea4ec054ca8.
>   ("x86/refcount: Work around GCC inlining bug")
>   (Conflicts: arch/x86/include/asm/refcount.h)
> 
> - c06c4d8090513f2974dfdbed2ac98634357ac475.
>   ("x86/objtool: Use asm macros to work around GCC inlining bugs")
> 
> - 77b0bf55bc675233d22cd5df97605d516d64525e.
>   ("kbuild/Makefile: Prepare for using macros in inline assembly code to work around asm() related GCC inlining bugs")
> 

I don't think we want to blindly revert all that. Some of them actually
made sense and did clean up things irrespective of the asm-inline issue.

In particular I like the jump-label one. The cpufeature one OTOh, yeah,
I'd love to get that reverted.

And as a note; the normal commit quoting style is:

  d5a581d84ae6 ("x86/cpufeature: Macrofy inline assembly code to work around GCC inlining bugs")