linux-kernel - Re: [PATCH v11 RESEND 9/9] arm64: armv8_deprecated: apply FEAT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <86ms3knl6s.wl-maz@kernel.org>
Date: Mon, 15 Dec 2025 09:33:47 +0000
From: Marc Zyngier <maz@...nel.org>
To: Yeoreum Yun <yeoreum.yun@....com>
Cc: catalin.marinas@....com,
	will@...nel.org,
	broonie@...nel.org,
	oliver.upton@...ux.dev,
	miko.lenczewski@....com,
	kevin.brodsky@....com,
	ardb@...nel.org,
	suzuki.poulose@....com,
	lpieralisi@...nel.org,
	yangyicong@...ilicon.com,
	scott@...amperecomputing.com,
	joey.gouly@....com,
	yuzenghui@...wei.com,
	pbonzini@...hat.com,
	shuah@...nel.org,
	mark.rutland@....com,
	arnd@...db.de,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	kvmarm@...ts.linux.dev,
	kvm@...r.kernel.org,
	linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v11 RESEND 9/9] arm64: armv8_deprecated: apply FEAT_LSUI for swpX emulation.

On Sun, 14 Dec 2025 11:22:48 +0000,
Yeoreum Yun <yeoreum.yun@....com> wrote:
> 
> Apply the FEAT_LSUI instruction to emulate the deprecated swpX
> instruction, so that toggling of the PSTATE.PAN bit can be removed when
> LSUI-related instructions are used.
> 
> Signed-off-by: Yeoreum Yun <yeoreum.yun@....com>

It really begs the question: what are the odds of ever seeing a CPU
that implements both LSUI and AArch32?

This seems extremely unlikely to me.

	M.

-- 
Without deviation from the norm, progress is not possible.