Re: [PATCH v2 1/6] rust: module: add static pointer to `{init,cleanup}_module()`

[Gary Guo <gary@garyguo.net>]

On Wed, 24 Jul 2024 18:14:54 +0200
Miguel Ojeda <ojeda@kernel.org> wrote:

> Add the equivalent of the `___ADDRESSABLE()` annotation in the
> `module_{init,exit}` macros to the Rust `module!` macro.
> 
> Without this, `objtool` would complain if enabled for Rust, e.g.:
> 
>     samples/rust/rust_print.o: warning: objtool: cleanup_module(): not an indirect call target
>     samples/rust/rust_print.o: warning: objtool: init_module(): not an indirect call target
> 
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
> ---
>  rust/macros/module.rs | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/rust/macros/module.rs b/rust/macros/module.rs
> index 411dc103d82e..571ffa2e189c 100644
> --- a/rust/macros/module.rs
> +++ b/rust/macros/module.rs
> @@ -256,6 +256,12 @@ mod __module_init {{
>                          unsafe {{ __init() }}
>                      }}
>  
> +                    #[cfg(MODULE)]
> +                    #[doc(hidden)]
> +                    #[used]
> +                    #[link_section = \".init.data\"]

Should this be in section `.discard.addressable` instead?

> +                    static __UNIQUE_ID___addressable_init_module: unsafe extern \"C\" fn() -> i32 = init_module;
> +
>                      #[cfg(MODULE)]
>                      #[doc(hidden)]
>                      #[no_mangle]
> @@ -269,6 +275,12 @@ mod __module_init {{
>                          unsafe {{ __exit() }}
>                      }}
>  
> +                    #[cfg(MODULE)]
> +                    #[doc(hidden)]
> +                    #[used]
> +                    #[link_section = \".exit.data\"]
> +                    static __UNIQUE_ID___addressable_cleanup_module: extern \"C\" fn() = cleanup_module;
> +
>                      // Built-in modules are initialized through an initcall pointer
>                      // and the identifiers need to be unique.
>                      #[cfg(not(MODULE))]