Re: [PATCH 00/15] exec: Remove AT_VECTOR_SIZE_ARCH from UAPI

[Kees Cook]

On Mon, Mar 02, 2026 at 01:25:24PM +0100, Thomas Weißschuh wrote:
> There is nothing userspace can do with this value. In the kernel is
> always combined with AT_VECTOR_SIZE_BASE, which is not exposed to
> userspace and also changes from time to time.
> 
> Move the symbol to kernel-internal headers.
> 
> Meant to be applied through the asm-generic tree.
> The default recipient list was huge. I trimmed it to only the
> architecture lists.

I don't see anything in Debian Code Search that actually uses this
symbol, so that seems fine. Userspace already parses auxvec looking for
AT_NULL, so length isn't useful.

Reviewed-by: Kees Cook <kees@xxxxxxxxxx>

> 
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
> ---
> Thomas Weißschuh (15):
>       MAINTAINERS: exec: Add more auxvec.h variants
>       auxvec.h: Move AT_VECTOR_SIZE definitions to linux/auxvec.h
>       asm-generic: add an in-kernel auxvec.h header
>       ARM: drop custom asm/auxvec.h
>       x86: Remove AT_VECTOR_SIZE_ARCH from UAPI
>       arm64: Remove AT_VECTOR_SIZE_ARCH from UAPI
>       RISC-V: Remove AT_VECTOR_SIZE_ARCH from UAPI
>       LoongArch: Remove AT_VECTOR_SIZE_ARCH from UAPI
>       s390: Remove AT_VECTOR_SIZE_ARCH from UAPI
>       powerpc: Remove AT_VECTOR_SIZE_ARCH from UAPI
>       MIPS: Remove AT_VECTOR_SIZE_ARCH from UAPI
>       sparc: Remove AT_VECTOR_SIZE_ARCH from UAPI
>       sh: Remove AT_VECTOR_SIZE_ARCH from UAPI
>       alpha: remove AT_VECTOR_SIZE_ARCH from UAPI
>       auxvec.h: Drop fallback AT_VECTOR_SIZE_ARCH
> 
>  MAINTAINERS                              |  5 +++++
>  arch/alpha/include/asm/auxvec.h          |  7 +++++++
>  arch/alpha/include/uapi/asm/auxvec.h     |  8 +++-----
>  arch/arm/include/asm/auxvec.h            |  1 -
>  arch/arm64/include/asm/auxvec.h          |  7 +++++++
>  arch/arm64/include/uapi/asm/auxvec.h     |  6 ++----
>  arch/loongarch/include/asm/auxvec.h      | 14 ++++++++++++++
>  arch/loongarch/include/uapi/asm/auxvec.h |  8 +++-----
>  arch/mips/include/asm/auxvec.h           | 17 +++++++++++++++++
>  arch/mips/include/uapi/asm/auxvec.h      |  8 +++-----
>  arch/powerpc/include/asm/auxvec.h        |  7 +++++++
>  arch/powerpc/include/uapi/asm/auxvec.h   |  6 ++----
>  arch/riscv/include/asm/auxvec.h          | 13 +++++++++++++
>  arch/riscv/include/uapi/asm/auxvec.h     |  2 --
>  arch/s390/include/asm/auxvec.h           |  7 +++++++
>  arch/s390/include/uapi/asm/auxvec.h      |  6 ++----
>  arch/sh/include/asm/auxvec.h             |  7 +++++++
>  arch/sh/include/uapi/asm/auxvec.h        |  8 +++-----
>  arch/sparc/include/asm/auxvec.h          |  6 ++++++
>  arch/sparc/include/uapi/asm/auxvec.h     |  8 +++-----
>  arch/x86/include/asm/auxvec.h            | 12 ++++++++++++
>  arch/x86/include/uapi/asm/auxvec.h       | 13 +++----------
>  include/asm-generic/Kbuild               |  1 +
>  include/asm-generic/auxvec.h             |  7 +++++++
>  include/linux/auxvec.h                   |  5 +++++
>  include/linux/mm_types.h                 |  6 ------
>  26 files changed, 139 insertions(+), 56 deletions(-)
> ---
> base-commit: f6b3b0a4c85882ad75bce3b093173203e3f39f28
> change-id: 20260109-at-vector-size-arch-6e0f2e9ff8b6
> 
> Best regards,
> -- 
> Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
> 

-- 
Kees Cook