linux-kernel - Re: [PATCH v2 0/3] arm64/sme: Support disabling streaming mode via ptrace on SME only systems

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] [day] [month] [year] [list]

Message-ID: <176341325906.789443.15370787298292895484.b4-ty@arm.com>
Date: Mon, 17 Nov 2025 21:00:59 +0000
From: Catalin Marinas <cmarinas@...nel.org>
To: Will Deacon <will@...nel.org>,
	Shuah Khan <shuah@...nel.org>,
	Jonathan Corbet <corbet@....net>,
	Oleg Nesterov <oleg@...hat.com>,
	Mark Brown <broonie@...nel.org>
Cc: Catalin Marinas <catalin.marinas@....com>,
	Mark Rutland <mark.rutland@....com>,
	David Spickett <david.spickett@....com>,
	Thiago Jung Bauermann <thiago.bauermann@...aro.org>,
	Luis Machado <luis.machado.foss@...il.com>,
	linux-arm-kernel@...ts.infradead.org,
	linux-kselftest@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-doc@...r.kernel.org
Subject: Re: [PATCH v2 0/3] arm64/sme: Support disabling streaming mode via ptrace on SME only systems

From: Catalin Marinas <catalin.marinas@....com>

On Wed, 15 Oct 2025 18:56:35 +0100, Mark Brown wrote:
> Currently it is not possible to disable streaming mode via ptrace on SME
> only systems, the interface for doing this is to write via NT_ARM_SVE but
> such writes will be rejected on a system without SVE support. Enable this
> functionality by allowing userspace to write SVE_PT_REGS_FPSIMD format data
> via NT_ARM_SVE with the vector length set to 0 on SME only systems. Such
> writes currently error since we require that a vector length is specified
> which should minimise the risk that existing software is relying on current
> behaviour.
> 
> [...]

I don't think we'll get gdb feedback soon. Thanks David for the LLDB
ack.

Applied to arm64 (for-next/sme-ptrace-disable), thanks!

[1/3] arm64/sme: Support disabling streaming mode via ptrace on SME only systems
      https://git.kernel.org/arm64/c/472800cd5e38
[2/3] kselftst/arm64: Test NT_ARM_SVE FPSIMD format writes on non-SVE systems
      https://git.kernel.org/arm64/c/eb9df6d69a96
[3/3] kselftest/arm64: Cover disabling streaming mode without SVE in fp-ptrace
      https://git.kernel.org/arm64/c/a0245b42f881

-- 
Catalin