Re: [PATCH v5 4/9] riscv: ptrace: validate input vector csr registers

Andy Chiu
2026-01-21T21:07:40Z

Hi Sergey,

On Sun, Dec 14, 2025 at 10:35 AM Sergey Matyukevich <geomatsi@gmail.com> wrote:
>
> Add strict validation for vector csr registers when setting them via
> ptrace:
> - reject attempts to set reserved bits or invalid field combinations
> - enforce strict VL checks against calculated VLMAX values
>
> Vector specs 0.7.1 and 1.0 allow normal applications to set candidate
> VL values and read back the hardware-adjusted results, see section 6
> for details. Disallow such flexibility in vector ptrace operations
> and strictly enforce valid VL input.
>
> The traced process may not update its saved vector context if no vector
> instructions execute between breakpoints. So the purpose of the strict
> ptrace approach is to make sure that debuggers maintain an accurate view
> of the tracee's vector context across multiple halt/resume debug cycles.
>
> Signed-off-by: Sergey Matyukevich <geomatsi@gmail.com>

Reviewed-by: Andy Chiu <andybnac@gmail.com>

Thanks,
Andy