Re: [PATCH v9 1/2] module: Extend module_blacklist parameter to built-in modules

[Petr Pavlu <petr.pavlu@suse.com>]

On 8/7/26 3:26 AM, Aaron Tomlin wrote:
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index 5659f4b5a125..799d912dcbc0 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -734,7 +734,9 @@
>  	EARLYCON_TABLE()						\
>  	LSM_TABLE()							\
>  	EARLY_LSM_TABLE()						\
> -	KUNIT_INIT_TABLE()
> +	KUNIT_INIT_TABLE()						\
> +	STRUCT_ALIGN();							\
> +	BOUNDED_SECTION_BY(.initcall.modnames, _initcall_modnames)
>  
>  #define INIT_TEXT							\
>  	*(.init.text .init.text.*)					\

I realized that instead of using STRUCT_ALIGN(), a cleaner and less
wasteful approach is to prevent any potential over-alignment of
individual .initcall.modnames sections by having
____define_initcall_modname() define each `struct initcall_modname` with
`__aligned(__alignof__(struct initcall_modname))`.

> diff --git a/rust/macros/module.rs b/rust/macros/module.rs
> index 06c18e207508..13353b43b38d 100644
> --- a/rust/macros/module.rs
> +++ b/rust/macros/module.rs
> @@ -479,6 +479,7 @@ pub(crate) fn module(info: ModuleInfo) -> Result<TokenStream> {
>      let ident_init = format_ident!("__{ident}_init");
>      let ident_exit = format_ident!("__{ident}_exit");
>      let ident_initcall = format_ident!("__{ident}_initcall");
> +    let ident_modname = format_ident!("__{ident}_modname");
>      let initcall_section = ".initcall6.init";
>  
>      let global_asm = format!(
> @@ -590,6 +591,21 @@ pub extern "C" fn cleanup_module() {
>                  #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
>                  ::core::arch::global_asm!(#global_asm);
>  
> +                #[cfg(not(MODULE))]
> +                #[repr(C)]
> +                struct InitcallModname {
> +                    initcall_fn: extern "C" fn() -> ::kernel::ffi::c_int,
> +                    modname: *const ::kernel::ffi::c_char,
> +                }
> +
> +                #[cfg(not(MODULE))]
> +                #[used(compiler)]
> +                #[link_section = ".initcall.modnames"]
> +                static #ident_modname: InitcallModname = InitcallModname {

Can Rust directly use the C definition of initcall_modname via
::kernel::bindings::initcall_modname?

> +                    initcall_fn: #ident_init,
> +                    modname: #name_cstr.as_ptr().cast(),

Can the modname string be placed in .init.rodata to match the behavior
on the C side?

> +                };
> +
>                  #[cfg(not(MODULE))]
>                  #[no_mangle]
>                  pub extern "C" fn #ident_init() -> ::kernel::ffi::c_int {

-- 
Thanks,
Petr