linux-kernel - Re: [PATCH 02/17] x86, lto: Mark all top level asm statements as .text

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Date:   Wed, 27 Mar 2019 22:55:44 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Andi Kleen <ak@...ux.intel.com>
cc:     Andi Kleen <andi@...stfloor.org>, x86@...nel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>
Subject: Re: [PATCH 02/17] x86, lto: Mark all top level asm statements as
 .text

On Wed, 27 Mar 2019, Andi Kleen wrote:
> > 
> > It's static so it's scope is within the file and whatever GCC does with
> > that C function it has to respect that it accesses static data. If that's
> > not true then this really needs to be fixed at the compiler side and not in
> > the kernel.
> 
> Ok so you did the statics with undefined size, so kind of an extern static. 
> That's a weird construct (not sure if it's even allowed in standard C), but
> somehow it seems to work in gcc with the inline assembler.

Strict C89 does not allow that, but it does not allow a lot of other things
the kernel does.

> I checked the code general and with the .globl in NATIVE_LABEL the

With or without? I removed that as well.

> generated assembler looks like it should work even for LTO yes.
> 
> I guess it's an interesting alternative to making them all global.
> Maybe that will work for more cases too.

Pretty much preferred over making static stuff global all over the place.

Thanks,

	tglx