From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Karl Mehltretter <kmehltretter@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>,
Dmitry Baryshkov <lumag@kernel.org>,
Sudeep Holla <sudeep.holla@kernel.org>,
Pierre Gondois <pierre.gondois@arm.com>,
Linus Walleij <linusw@kernel.org>,
Radu Rendec <rrendec@redhat.com>,
Clark Williams <clrkwllms@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
linux-arm-kernel@lists.infradead.org,
linux-rt-devel@lists.linux.dev, linux-kernel@vger.kernel.org,
Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH 0/4] ARM: allocate the cacheinfo early to fix the PREEMPT_RT boot warning
Date: Wed, 16 Sep 2026 10:44:04 +0200 [thread overview]
Message-ID: <20260916084404.fjkCQKUK@linutronix.de> (raw)
In-Reply-To: <20260912195552.76673-1-kmehltretter@gmail.com>
On 2026-09-12 21:55:48 [+0200], Karl Mehltretter wrote:
> This series moves ARM cacheinfo allocation to the boot CPU to avoid
> sleeping-lock warnings during PREEMPT_RT secondary-CPU startup. It is
> based on 5225b8eec4c9 (7.3-rc2 plus one day).
>
> Patches 1-3 prepare for early allocation: bound cache-leaf writes,
> include external caches in the allocation size, and guard CLIDR reads
> on older CPUs. Patch 4 enables early allocation. Please take all four
> patches together for stable.
>
> Tested on QEMU virt (Cortex-A15), vexpress-a9 (Cortex-A9 with PL310),
> and realview-eb-mpcore (ARM11 MPCore) with PREEMPT_RT, plus non-RT
> virt and vexpress-a9 builds. Cache sysfs output is unchanged for the
> normal platform DTs, and CPU hotplug passes where supported. Additional
> checks cover DT leaf undercounting with KASAN and ARM11 DT cache
> descriptions.
>
> The full series also passes on a Raspberry Pi 400 with a 32-bit
> PREEMPT_RT 7.2.6-rc1 kernel: the boot warning is absent and all 12 cache
> sysfs entries match the baseline. CPU hotplug is unavailable there.
This makes sense.
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Sebastian
prev parent reply other threads:[~2026-09-16 8:44 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-12 19:55 Karl Mehltretter
2026-09-12 19:55 ` [PATCH 1/4] ARM: cacheinfo: avoid out-of-bounds write in populate_cache_leaves() Karl Mehltretter
2026-09-12 19:55 ` [PATCH 2/4] ARM: cacheinfo: count external caches in early_cache_level() Karl Mehltretter
2026-09-12 20:09 ` sashiko-bot
2026-09-12 19:55 ` [PATCH 3/4] ARM: cacheinfo: guard the CLIDR read in populate_cache_leaves() Karl Mehltretter
2026-09-12 19:55 ` [PATCH 4/4] ARM: topology: allocate the cacheinfo early on the boot CPU Karl Mehltretter
2026-09-16 8:44 ` Sebastian Andrzej Siewior [this message]
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