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

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Message-ID: <4ce6cf96-685d-4792-b2fd-949c07eff707@kernel.org>
Date: Tue, 30 Apr 2024 07:15:29 +0200
From: Jiri Slaby <jirislaby@...nel.org>
To: Michael Matz <matz@...e.de>, Borislav Petkov <bp@...en8.de>
Cc: 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

Hi,

On 29. 04. 24, 14:05, Michael Matz wrote:
> On Sat, 20 Apr 2024, Borislav Petkov wrote:
> 
>> Interesting. I thought gcc doesn't have problems here yet and was
>> talking to Matz on Thu about it and it seems he's forgotten about his
>> statement too that "you should simply stop using -mcmodel=large.  Noone
>> should use it." :-)
> 
> 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.  And indeed I know of no
> particular problems with it vis GCC,

Of course you do :). That bsc#1211853 I linked earlier. I.e. gcc-13 + 
-fstrict-flex-arrays=3 + -mcmodel=large + some asm() expecting __FILE__ 
to be constant (not true with the large model).

regards,
-- 
js
suse labs