From: "Arnd Bergmann" <arnd@arndb.de>
To: "David Laight" <david.laight.linux@gmail.com>,
"Arnd Bergmann" <arnd@kernel.org>
Cc: "Ingo Molnar" <mingo@redhat.com>,
"Richard Weinberger" <richard@nod.at>,
"Anton Ivanov" <anton.ivanov@cambridgegreys.com>,
"Johannes Berg" <johannes@sipsolutions.net>,
"Thomas Gleixner" <tglx@kernel.org>,
"Borislav Petkov" <bp@alien8.de>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Will Deacon" <will@kernel.org>, "Boqun Feng" <boqun@kernel.org>,
"Gary Guo" <gary@garyguo.net>,
"Yury Norov" <yury.norov@gmail.com>,
"Rasmus Villemoes" <linux@rasmusvillemoes.dk>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"Alexander Usyskin" <alexander.usyskin@intel.com>,
"Anthony L Nguyen" <anthony.l.nguyen@intel.com>,
"Przemek Kitszel" <przemyslaw.kitszel@intel.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
linux-um@lists.infradead.org
Subject: Re: [PATCH 3/7] x86: make CX8 usage unconditional
Date: Mon, 09 Nov 2026 11:24:10 +0100 [thread overview]
Message-ID: <b0e3b33c-37fe-401e-9f97-a2753ed6e22a@app.fastmail.com> (raw)
In-Reply-To: <20261108203042.7e36f15b@pumpkin>
On Sun, Nov 8, 2026, at 21:30, David Laight wrote:
> On Thu, 5 Nov 2026 17:34:34 +0100
> Arnd Bergmann <arnd@kernel.org> wrote:
>
>> From: Arnd Bergmann <arnd@arndb.de>
>>
>> All supported CPUs now provide the cmpxchg8b instruction, so remove
>> all compile-time and runtime checks for its presence and the fallback
>> implementation, to assume it just works.
>
> Is it worth doing a run-time check early on any (trying) to output
> a message and fail to boot?
I think the existing checks in arch/x86/boot/cpucheck.c should be
enough here, as they cover all known pre-586 CPUs and anyone running
some other CPU that we can't detect is already on their own.
Arnd
next prev parent reply other threads:[~2026-11-09 10:25 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-05 16:34 [PATCH v2 0/7] x86-32 CPU configuration cleanups Arnd Bergmann
2026-11-05 16:34 ` [PATCH 1/7] x86: remove AMD Élan remnants Arnd Bergmann
2026-11-05 16:34 ` [PATCH 2/7] x86: make TSC usage unconditional Arnd Bergmann
2026-11-05 16:34 ` [PATCH 3/7] x86: make CX8 " Arnd Bergmann
2026-11-05 22:30 ` Uros Bizjak
2026-11-09 10:20 ` Arnd Bergmann
2026-11-06 2:29 ` kernel test robot
2026-11-06 15:43 ` David Gow
2026-11-08 20:30 ` David Laight
2026-11-09 10:24 ` Arnd Bergmann [this message]
2026-11-05 16:34 ` [PATCH 4/7] x86: require minimum 64 byte cache lines Arnd Bergmann
2026-11-05 16:34 ` [PATCH 5/7] x86: remove dependencies on CONFIG_M... CPU options Arnd Bergmann
2026-11-05 16:34 ` [PATCH 6/7] x86: remove dependencies on per-CPU options Arnd Bergmann
2026-11-05 16:34 ` [PATCH 7/7] x86: simplify 32-bit instruction set selection Arnd Bergmann
2026-11-05 20:17 ` H. Peter Anvin
2026-11-05 22:01 ` Arnd Bergmann
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