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

Message-ID: <05dd180e-f12f-44ef-96e2-2a6013da14df@gmail.com>
Date: Fri, 21 Nov 2025 11:25:30 +0000
From: Luis <luis.machado.foss@...il.com>
To: Catalin Marinas <cmarinas@...nel.org>, 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>, 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

[off-list, as I'm having bouncing issues]

Hi,

On 17/11/2025 21:00, Catalin Marinas wrote:
> 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.

Unfortunately this flew under the radar for me, and I haven´t been 
following these discussions closely.

Is there someone working to rectify/validate this in GDB from Arm's side?

I´d gladly review it and get it through into upstream gdb.