From: David Laight <David.Laight@ACULAB.COM>
To: 'Nick Desaulniers' <ndesaulniers@google.com>,
Tor Vic <torvic9@mailbox.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"nathan@kernel.org" <nathan@kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"clang-built-linux@googlegroups.com"
<clang-built-linux@googlegroups.com>,
"x86@kernel.org" <x86@kernel.org>
Subject: RE: [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0
Date: Fri, 11 Jun 2021 08:07:54 +0000 [thread overview]
Message-ID: <6c8315ef3ebb45b59dd531c634bcff48@AcuMS.aculab.com> (raw)
In-Reply-To: <CAKwvOdmU9TUiZ6AatJja=ksneRKP5saNCkx0qodLMOi_BshSSg@mail.gmail.com>
From: Nick Desaulniers
> Sent: 10 June 2021 20:21
>
> On Thu, Jun 10, 2021 at 2:28 AM <torvic9@mailbox.org> wrote:
> >
> > Since LLVM commit 3787ee4, the '-stack-alignment' flag has been dropped [1],
> > leading to the following error message when building a LTO kernel with
> > Clang-13 and LLD-13:
> >
> > ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument
> > '-stack-alignment=8'. Try 'ld.lld --help'
> > ld.lld: Did you mean '--stackrealign=8'?
> >
> > It also appears that the '-code-model' flag is not necessary anymore starting
> > with LLVM-9 [2].
> >
> > Drop '-code-model' and make '-stack-alignment' conditional on LLD < 13.0.0.
>
> Please include this additional context in v2:
> ```
> These flags were necessary because these flags were not encoded in the
> IR properly, so the link would restart optimizations without them. Now
> there are properly encoded in the IR, and these flags exposing
> implementation details are no longer necessary.
> ```
> That way it doesn't sound like we're not using an 8B stack alignment
> on x86; we very much are so; AMDGPU GPFs without it!
Actually, give that LTO is still 'experimental' is it worth just
removing the flags and requiring clang-13 for LTO builds?
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
prev parent reply other threads:[~2021-06-11 8:08 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-10 9:28 [PATCH] x86/Makefile: make -stack-alignment conditional on LLD < 13.0.0 torvic9
2021-06-10 10:04 ` Greg KH
2021-06-10 16:42 ` Nathan Chancellor
2021-06-10 18:39 ` Tor Vic
2021-06-10 19:17 ` Nick Desaulniers
2021-06-10 19:20 ` Nick Desaulniers
2021-06-10 20:16 ` Tor Vic
2021-06-10 20:40 ` Nathan Chancellor
2021-06-11 8:07 ` David Laight [this message]
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