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

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Date:   Tue, 26 Mar 2019 18:03:59 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Andi Kleen <andi@...stfloor.org>
cc:     x86@...nel.org, akpm@...ux-foundation.org,
        linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH 02/17] x86, lto: Mark all top level asm statements as
 .text

Andi,

On Thu, 21 Mar 2019, Andi Kleen wrote:

> With gcc 8 toplevel assembler statements that do not mark themselves
> as .text may end up in other sections.

Which is clearly a change in behaviour. Is that intended or just yet
another feature of GCC?

Your subject says: 'x86, lto:'

So is this a LTO related problem or is the section randomization
independent of LTO?

This wants to be clearly documented in the changelog.

Aside of that the proper Subject prefix is either:

    x86/asm/lto:

or

    x86/asm:

dependent on the nature. Like it or not, but this has been the prefix x86
uses for a very long time already.

> I had boot crashes because
> various assembler statements ended up in the middle of the initcall
> section.
> 
> Always mark all the top level assembler statements as text
> so that they switch to the right section.
> 
> For AMD "vide", which is only used on 32bit kernels, I also
> marked it as 32bit only.

Once more. See

  https://www.kernel.org/doc/html/latest/process/submitting-patches.html#describe-your-changes

  "Describe your changes in imperative mood, e.g. “make xyzzy do frotz”
  instead of “[This patch] makes xyzzy do frotz” or “[I] changed xyzzy to
  do frotz”, as if you are giving orders to the codebase to change its
  behaviour."

This is the last time, I'm asking for this.

Thanks,

	tglx