From: "Luck, Tony" <tony.luck@intel.com>
To: David Laight <David.Laight@ACULAB.COM>,
'Thomas Gleixner' <tglx@linutronix.de>,
Pavel Machek <pavel@denx.de>
Cc: "Yu, Fenghua" <fenghua.yu@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"patches@lists.linux.dev" <patches@lists.linux.dev>
Subject: RE: [PATCH v2 1/2] x86/split_lock: Make life miserable for split lockers
Date: Thu, 17 Mar 2022 22:40:16 +0000 [thread overview]
Message-ID: <8ceaa1e7624b46feafb15da0935e161c@intel.com> (raw)
In-Reply-To: <e2baf93885684512b4c7dc5363620a6f@AcuMS.aculab.com>
> They are actually more likely to happen in the kernel
> when code casts int[] to long[] and then uses the 'BIT' functions to
> set/clear bits - which do locked operations.
> Quite often then don't need the locks anyway.
> And that cast is surprisingly common and completely broken on BE.
Default split lock mode is "kernel dies". We had to fix up a dozen or
so places (mostly involving set_bit/clr_bit as you describe). But
all Ice Lake. Tiger Lake and Alder Lake systems are running in
that mode ... and we haven't heard of widespread death (or disabling
the boot option).
-Tony
next prev parent reply other threads:[~2022-03-17 22:40 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-17 1:27 [PATCH] x86/split_lock: Make life miserable for split lockers Tony Luck
2022-03-07 22:30 ` Thomas Gleixner
2022-03-08 0:37 ` Luck, Tony
2022-03-08 14:59 ` Thomas Gleixner
2022-03-08 17:12 ` Luck, Tony
2022-03-10 20:48 ` [PATCH v2 0/2] " Tony Luck
2022-03-10 20:48 ` [PATCH v2 1/2] x86/split_lock: " Tony Luck
2022-03-17 11:13 ` Pavel Machek
2022-03-17 16:27 ` Luck, Tony
2022-03-17 18:06 ` Thomas Gleixner
2022-03-17 22:21 ` David Laight
2022-03-17 22:40 ` Luck, Tony [this message]
2022-03-18 12:21 ` Fenghua Yu
2022-04-27 13:49 ` [tip: x86/splitlock] " tip-bot2 for Tony Luck
2022-03-10 20:48 ` [PATCH v2 2/2] x86/split-lock: Remove unused TIF_SLD bit Tony Luck
2022-04-27 13:49 ` [tip: x86/splitlock] " tip-bot2 for Tony Luck
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