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From:   Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Date:   Tue, 18 Sep 2018 20:56:04 +0200
Message-ID: <CANiq72=ZU61EaoWm2N4G1SZF0QUvzquULo50uEvDRU-hitOJVQ@mail.gmail.com>
Subject: Re: [PATCH v2 2/2] Compiler Attributes: naked can be shared
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-kernel <linux-kernel@vger.kernel.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Eli Friedman <efriedma@codeaurora.org>,
        Christopher Li <sparse@chrisli.org>,
        Kees Cook <keescook@chromium.org>,
        Ingo Molnar <mingo@kernel.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Joe Perches <joe@perches.com>,
        Dominique Martinet <asmadeus@codewreck.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-sparse@vger.kernel.org
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Hi Greg,

On Tue, Sep 18, 2018 at 7:34 PM, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
> On Tue, Sep 18, 2018 at 06:55:42PM +0200, Miguel Ojeda wrote:
>> The naked attribute is supported by at least gcc >= 4.6 (for ARM,
>> which is the only current user), gcc >= 8 (for x86), clang >= 3.1
>> and icc >= 13. See https://godbolt.org/z/350Dyc
>>
>> Therefore, move it out of compiler-gcc.h so that the definition
>> is shared by all compilers.
>>
>> This also fixes Clang support for ARM32 --- 815f0ddb346c
>> ("include/linux/compiler*.h: make compiler-*.h mutually exclusive").
>
> So, with this applied, does clang really build an arm32 kernel
> successfully?  No other problem at all?  And this isn't really a
> regression, arm32 never really worked with clang yet, right?
>

To recap a bit: these two patches come from the "Compiler Attributes"
series which is meant as a general improvement. Since Linus/Andrew/you
didn't comment on whether you wanted or not this for 4.19, we are
assuming they would go in for 4.20. However, Stefan/Nick/... wanted
this for 4.19 instead, they asked me to extract these patches two
separately for 4.19. I let them comment further on the status of Clang
on arm32.

I am going to send a v5 of the entire series without these two
patches, based on -rc4 (or -next, which one do you prefer? I would say
these patches should be applied early in the -next branches, so that
everyone is ready for the change, given it "touches" every translation
unit).

Cheers,
Miguel