Re: [PATCH v1] rust: jump_label: skip arch-specific asm in `testlib` builds

On Sun, Aug 9, 2026 at 3:49 PM FUJITA Tomonori <[email protected]> wrote:
>
> From: FUJITA Tomonori <[email protected]>
>
> Running `make rusttest` with `ARCH=` set to an architecture other than
> the host's fails, e.g. `ARCH=arm64` on an x86_64 host:
>
> error: alignment must be a power of 2
>   --> rust/kernel/jump_label.rs:51:13
>    |
> 51 |     include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_static_branch_asm.rs"));
>    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>    |
> note: instantiated into assembly here
>   --> <inline asm>:3:10
>    |
>  3 |     .align        3
>    |                   ^
>
> The reason is that `rusttest` builds the kernel crate as a host
> library: it passes the `CONFIG_*` cfgs of the configured architecture,
> but not `--target`, so code generation happens for the
> host. `arch_static_branch!` then selects the arch-specific inline asm
> arm based on CONFIG_*, and the host assembler rejects it.
>
> This does not happen with the current master because
> `arch_static_branch!` has no user inside the kernel crate itself yet,
> but fix it now to avoid surprises later.
>
> Signed-off-by: FUJITA Tomonori <[email protected]>

Applied to `rust-fixes` -- thanks!

    [ Reworded slightly to clarify it "may fail in the future". - Miguel ]

Cheers,
Miguel