Linux Kernel Selftest development
 help / color / mirror / Atom feed
From: Yeoreum Yun <yeoreum.yun@arm.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Mark Brown <broonie@kernel.org>,
	Oliver Upton <oliver.upton@linux.dev>,
	miko.lenczewski@arm.com, Kevin Brodsky <kevin.brodsky@arm.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Lorenzo Pieralisi <lpieralisi@kernel.org>,
	yangyicong@hisilicon.com, scott@os.amperecomputing.com,
	Joey Gouly <joey.gouly@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Paolo Bonzini <pbonzini@redhat.com>, shuah <shuah@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev,
	kvm@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v11 9/9] arm64: armv8_deprecated: apply FEAT_LSUI for swpX emulation.
Date: Fri, 7 Nov 2025 15:57:03 +0000	[thread overview]
Message-ID: <aQ4WzxQl+aVJcBaL@e129823.arm.com> (raw)
In-Reply-To: <a9f4eb49-b06e-4941-a75a-df39f5d3d735@app.fastmail.com>

Hi Arnd,

> >> > apply FEAT_LSUI instruction to emulate deprecated swpX instruction.
> >>
> >> Can you explain in the changrelog why you do this?
> >>
> >> In particular, is this a performance optimization or is this required
> >> for correctness in some scenario?
> >
> > I think the main purpose using for this is to "remove the toggling the
> > PSTATE.PAN" bit. so that remove some *potential* problem which can
> > happen when PAN bit is cleared.
>
> Ok, I see. This should definitely be part of the commit
> log for the patch in addition to the cover letter.

Thanks. I'll add detail in next spin after receving other comments.

[...]

--
Sincerely,
Yeoreum Yun

      reply	other threads:[~2025-11-07 15:57 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-06  9:40 [PATCH v11 0/9] support FEAT_LSUI Yeoreum Yun
2025-11-06  9:40 ` [PATCH v11 1/9] arm64: cpufeature: add FEAT_LSUI Yeoreum Yun
2025-11-06  9:40 ` [PATCH v11 2/9] KVM: arm64: expose FEAT_LSUI to guest Yeoreum Yun
2025-11-06  9:40 ` [PATCH v11 3/9] KVM: arm64: kselftest: set_id_regs: add test for FEAT_LSUI Yeoreum Yun
2025-11-06  9:40 ` [PATCH v11 4/9] arm64: Kconfig: Detect toolchain support for LSUI Yeoreum Yun
2025-11-06  9:40 ` [PATCH v11 5/9] arm64: futex: refactor futex atomic operation Yeoreum Yun
2025-11-06  9:40 ` [PATCH v11 6/9] arm64: futex: support futex with FEAT_LSUI Yeoreum Yun
2025-11-06  9:40 ` [PATCH v11 7/9] arm64: separate common LSUI definitions into lsui.h Yeoreum Yun
2025-11-06  9:40 ` [PATCH v11 8/9] arm64: armv8_deprecated: convert user_swpX to inline function Yeoreum Yun
2025-11-06  9:40 ` [PATCH v11 9/9] arm64: armv8_deprecated: apply FEAT_LSUI for swpX emulation Yeoreum Yun
2025-11-07 11:52   ` Arnd Bergmann
2025-11-07 14:19     ` Yeoreum Yun
2025-11-07 14:24       ` Arnd Bergmann
2025-11-07 15:57         ` Yeoreum Yun [this message]

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=aQ4WzxQl+aVJcBaL@e129823.arm.com \
    --to=yeoreum.yun@arm.com \
    --cc=ardb@kernel.org \
    --cc=arnd@arndb.de \
    --cc=broonie@kernel.org \
    --cc=catalin.marinas@arm.com \
    --cc=joey.gouly@arm.com \
    --cc=kevin.brodsky@arm.com \
    --cc=kvm@vger.kernel.org \
    --cc=kvmarm@lists.linux.dev \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=lpieralisi@kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=maz@kernel.org \
    --cc=miko.lenczewski@arm.com \
    --cc=oliver.upton@linux.dev \
    --cc=pbonzini@redhat.com \
    --cc=scott@os.amperecomputing.com \
    --cc=shuah@kernel.org \
    --cc=suzuki.poulose@arm.com \
    --cc=will@kernel.org \
    --cc=yangyicong@hisilicon.com \
    --cc=yuzenghui@huawei.com \
    /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