linux-kernel - Re: [PATCH] x86/purgatory: Switch to the position-independent small code model

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Message-ID: <20240429123022.GBZi-S3p4vlPK10pYM@fat_crate.local>
Date: Mon, 29 Apr 2024 14:30:22 +0200
From: Borislav Petkov <bp@...en8.de>
To: Michael Matz <matz@...e.de>
Cc: Jiri Slaby <jirislaby@...nel.org>, Ard Biesheuvel <ardb+git@...gle.com>,
	linux-kernel@...r.kernel.org, x86@...nel.org,
	Ard Biesheuvel <ardb@...nel.org>,
	Nathan Chancellor <nathan@...nel.org>,
	Nick Desaulniers <ndesaulniers@...gle.com>,
	Bill Wendling <morbo@...gle.com>,
	Justin Stitt <justinstitt@...gle.com>, Song Liu <song@...nel.org>,
	Ricardo Ribalda <ribalda@...nel.org>,
	Fangrui Song <maskray@...gle.com>,
	Arthur Eubanks <aeubanks@...gle.com>, stable@...r.kernel.org
Subject: Re: [PATCH] x86/purgatory: Switch to the position-independent small
 code model

On Mon, Apr 29, 2024 at 02:05:12PM +0200, Michael Matz wrote:
> It may be so ingrained in my brain that I'm not _always_ saying it when 
> talking about the large code model over a beer.

Doh, you should. This is what you start with! :-P

> And indeed I know of no particular problems with it vis GCC, but that
> doesn't mean it's a good idea to use :-)
>
> So once again: "everyone should simply stop using -mcmodel=large.  Noone
> should use it."
>
> So the patch goes strictly into the direction of betterment of the
> universe. :)

Yeah, it is already on its way to every kernel near you. And looka here:

$ git grep mcmodel=large
arch/powerpc/Makefile:125:      # 64bit relocation for this to work, hence -mcmodel=large.
arch/powerpc/Makefile:126:      KBUILD_CFLAGS_MODULE += -mcmodel=large
arch/um/Makefile:34:    KBUILD_CFLAGS += -mcmodel=large

x86 is all free of the large model now.

One less thing to worry about - gazillion more to go.

:-P

See ya on Thu.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette