[PATCH v5 12/24] vdso: Add the vdsocheck tool

[Peter Zijlstra]

On Tue, Sep 08, 2026 at 08:33:46AM +0200, Thomas Weißschuh wrote:
> All vDSO code needs to be completely position independent. Symbol
> references are marked as hidden so the compiler emits PC-relative
> relocations. However there are cases where the compiler may still
> emit absolute relocations, as they are valid in regular PIC DSO code.
> These would be resolved by the linker and will break at runtime.
> This has been observed on arm64, see commit 0c314cda9325 ("arm64: vdso:
> Work around invalid absolute relocations from GCC")
> 
> Introduce a tool to check for absolute relocations during the build,
> as the current inline-shell logic is not expressive enough.
> The check is done on the object files as the relocations will not exist
> anymore in the final DSO. As there is no extension point for the
> compilation of each object file, perform the validation in vdso_check.
> 
> Signed-off-by: Thomas Weißschuh <thomas.weissschuh at linutronix.de>
> ---
>  Makefile                    |  19 ++
>  lib/vdso/Kconfig            |   5 +
>  lib/vdso/Makefile           |   2 +
>  lib/vdso/Makefile.include   |  14 ++
>  lib/vdso/check/.gitignore   |   3 +
>  lib/vdso/check/Makefile     |  34 +++
>  lib/vdso/check/elf.rs       | 498 ++++++++++++++++++++++++++++++++++++++++++++
>  lib/vdso/check/vdsocheck.rs | 154 ++++++++++++++
>  8 files changed, 729 insertions(+)

Urgh, does this mean I have to have rust installed just to build a
kernel now?