From: "Arnd Bergmann" <arnd@kernel.org>
To: "Linus Torvalds" <torvalds@linuxfoundation.org>,
"Thomas Gleixner" <tglx@linutronix.de>
Cc: "Guenter Roeck" <linux@roeck-us.net>,
LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, "Uros Bizjak" <ubizjak@gmail.com>,
linux-sparse@vger.kernel.org, "kernel test robot" <lkp@intel.com>,
oe-kbuild-all@lists.linux.dev
Subject: Re: [patch 5/9] x86: Cure per CPU madness on UP
Date: Sat, 16 Mar 2024 22:34:55 +0100 [thread overview]
Message-ID: <dd494544-6dbf-4e83-8060-1f8b7b07a8c4@app.fastmail.com> (raw)
In-Reply-To: <CAHk-=wg50AGnzhmOK0TNqDN99T3dWd747h3y-ZFuv4bNZ4Q0tw@mail.gmail.com>
On Sat, Mar 16, 2024, at 02:23, Linus Torvalds wrote:
> On Fri, 15 Mar 2024 at 18:11, Thomas Gleixner <tglx@linutronix.de> wrote:
>>
>> You wish. We still support 486 and some of the still produced 486 clones
>> do not have a local APIC.
>
> Ouch. I was _sure_ we had dropped i486 support too due to cmpxchg8b.
>
> But apparently that was just a discussion, and my wishful thinking,
> and we never actually followed through.
Maciej Rozycki still cares about i486 type hardware, and he was
asking for it to be kept around in the thread following [1]
I think the best suggestion at the time was to make cmpxchg8b
a compile-time feature and I had expected Maciej to follow up with
a patch for that, but this never happend, and nobody sent a patch
to remove support 486 and the early 586 clones either.
I saw recently that there are still distros that advertise 486
support on modern kernels: Tiny Core Linux and Damn Small
Linux. Both ship with a 486 SMP kernel but fail to boot
on qemu unless an APIC is enabled (DSL also requires i686 or
higher to run userspace).
Arnd
[1] https://lore.kernel.org/all/20220815071332.627393-9-yuzhao@google.com/
next prev parent reply other threads:[~2024-03-16 21:37 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-04 10:12 [patch 0/9] x86: Cure tons of sparse warnings (mostly __percpu) Thomas Gleixner
2024-03-04 10:12 ` [patch 1/9] perf/x86/amd/uncore: Fix __percpu annotation Thomas Gleixner
2024-03-04 10:12 ` [patch 2/9] x86/msr: Prepare for including percpu.h Thomas Gleixner
2024-03-04 10:12 ` [patch 3/9] x86/msr: Add missing __percpu annotations Thomas Gleixner
2024-03-04 10:12 ` [patch 4/9] smp: Consolidate smp_prepare_boot_cpu() Thomas Gleixner
2024-03-04 10:12 ` [patch 5/9] x86: Cure per CPU madness on UP Thomas Gleixner
2024-03-15 16:17 ` Guenter Roeck
2024-03-15 16:42 ` Linus Torvalds
2024-03-15 17:02 ` Guenter Roeck
2024-03-15 17:40 ` Thomas Gleixner
2024-03-15 22:55 ` Thomas Gleixner
2024-03-15 23:23 ` Linus Torvalds
2024-03-16 1:11 ` Thomas Gleixner
2024-03-16 1:23 ` Linus Torvalds
2024-03-16 21:34 ` Arnd Bergmann [this message]
2024-03-17 21:03 ` David Laight
2024-03-18 11:11 ` Thomas Gleixner
2024-03-18 17:27 ` Thomas Gleixner
2024-03-18 19:13 ` Arnd Bergmann
2024-03-19 16:21 ` Thomas Gleixner
2024-03-19 18:26 ` Guenter Roeck
2024-03-16 0:56 ` Guenter Roeck
2024-03-20 8:58 ` Thomas Gleixner
2024-03-20 15:46 ` Guenter Roeck
2024-03-21 11:14 ` Thomas Gleixner
2024-03-21 14:06 ` Guenter Roeck
2024-03-21 16:49 ` Thomas Gleixner
2024-03-04 10:12 ` [patch 6/9] x86/uaccess: Add missing __force to casts in __access_ok() and valid_user_address() Thomas Gleixner
2024-03-04 10:12 ` [patch 7/9] x86/cpu: Use EXPORT_PER_CPU_SYMBOL_GPL() for x86_spec_ctrl_current Thomas Gleixner
2024-03-04 10:12 ` [patch 8/9] x86/cpu: Provide a declaration for itlb_multihit_kvm_mitigation Thomas Gleixner
2024-03-04 10:12 ` [patch 9/9] x86/callthunks: Use EXPORT_PER_CPU_SYMBOL_GPL() for per CPU variables Thomas Gleixner
2024-03-04 11:08 ` [patch 0/9] x86: Cure tons of sparse warnings (mostly __percpu) Ingo Molnar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=dd494544-6dbf-4e83-8060-1f8b7b07a8c4@app.fastmail.com \
--to=arnd@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-sparse@vger.kernel.org \
--cc=linux@roeck-us.net \
--cc=lkp@intel.com \
--cc=oe-kbuild-all@lists.linux.dev \
--cc=tglx@linutronix.de \
--cc=torvalds@linuxfoundation.org \
--cc=ubizjak@gmail.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).