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

Luis
2025-11-21T11:25:33Z

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

Hi,

On 17/11/2025 21:00, Catalin Marinas wrote:
> From: Catalin Marinas <catalin.marinas@arm.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.