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Fri, 21 Nov 2025 08:30:43 -0800 (PST) From: Thiago Jung Bauermann To: Luis Cc: Catalin Marinas , Will Deacon , Shuah Khan , Jonathan Corbet , Oleg Nesterov , Mark Brown , Catalin Marinas , Mark Rutland , David Spickett , linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH v2 0/3] arm64/sme: Support disabling streaming mode via ptrace on SME only systems In-Reply-To: <05dd180e-f12f-44ef-96e2-2a6013da14df@gmail.com> (Luis's message of "Fri, 21 Nov 2025 11:25:30 +0000") References: <20251015-arm64-sme-ptrace-sme-only-v2-0-33c7b2f27cbf@kernel.org> <176341325906.789443.15370787298292895484.b4-ty@arm.com> <05dd180e-f12f-44ef-96e2-2a6013da14df@gmail.com> User-Agent: mu4e 1.12.13; emacs 30.2 Date: Fri, 21 Nov 2025 13:30:41 -0300 Message-ID: <87ms4fmjpq.fsf@linaro.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Luis writes: > [off-list, as I'm having bouncing issues] > > Hi, > > On 17/11/2025 21:00, Catalin Marinas wrote: >> From: Catalin Marinas >> 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 b= ut >>> such writes will be rejected on a system without SVE support. Enable th= is >>> 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 specifi= ed >>> which should minimise the risk that existing software is relying on cur= rent >>> 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=C2=B4t been f= ollowing these > discussions closely. > > Is there someone working to rectify/validate this in GDB from Arm's side? > > I=C2=B4d gladly review it and get it through into upstream gdb. I will work on it next week. --=20 Thiago