On 5/2/25 16:12, Peter Zijlstra wrote:
> Helper macro to more easily limit the export of a symbol to a given
> list of modules.
> 
> Eg:
> 
>   EXPORT_SYMBOL_GPL_FOR_MODULES(preempt_notifier_inc, "kvm");
> 
> will limit the use of said function to kvm.ko, any other module trying
> to use this symbol will refure to load (and get modpost build
> failures).
> 
> Requested-by: Masahiro Yamada <masahi...@kernel.org>
> Requested-by: Christoph Hellwig <h...@infradead.org>
> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
> ---
> [...]
> --- a/include/linux/export.h
> +++ b/include/linux/export.h
> @@ -24,11 +24,17 @@
>       .long sym
>  #endif
>  
> -#define ___EXPORT_SYMBOL(sym, license, ns)           \
> +/*
> + * LLVM integrated assembler cam merge adjacent string literals (like
> + * C and GNU-as) passed to '.ascii', but not to '.asciz' and chokes on:
> + *
> + *   .asciz "MODULE_" "kvm" ;
> + */

Typo: "cam" -> "can't". I can correct it when picking up the series.

Reviewed-by: Petr Pavlu <petr.pa...@suse.com>

-- Petr

> +#define ___EXPORT_SYMBOL(sym, license, ns...)                \
>       .section ".export_symbol","a"           ASM_NL  \
>       __export_symbol_##sym:                  ASM_NL  \
>               .asciz license                  ASM_NL  \
> -             .asciz ns                       ASM_NL  \
> +             .ascii ns "\0"                  ASM_NL  \
>               __EXPORT_SYMBOL_REF(sym)        ASM_NL  \
>       .previous
>  
> @@ -85,4 +91,6 @@
>  #define EXPORT_SYMBOL_NS(sym, ns)    __EXPORT_SYMBOL(sym, "", ns)
>  #define EXPORT_SYMBOL_NS_GPL(sym, ns)        __EXPORT_SYMBOL(sym, "GPL", ns)
>  
> +#define EXPORT_SYMBOL_GPL_FOR_MODULES(sym, mods) __EXPORT_SYMBOL(sym, "GPL", 
> "module:" mods)
> +
>  #endif /* _LINUX_EXPORT_H */
> 
> 

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