Re: [musl] [PATCH] make __getauxval a public ABI symbol

[Rich Felker <dalias@libc.org>]

On Thu, Oct 12, 2023 at 08:31:48PM +0200, Szabolcs Nagy wrote:
> This is needed so that libgcc can access AT_HWCAP without violating
> link namespace rules.
> 
> Internally musl already used __getauxval symbol for the same reason,
> we just remove the hidden marking.
> 
> Currently libgcc only uses __getauxval on aarch64 for outline atomics
> and only on glibc, but there is plan to add more usage (this time in
> the unwinder) which may cause link failure on musl in the future.
> (libgcc cannot easily check for libc symbols due to bootstrap order,
> the feature could be unconditionally disabled for *-linux-musl, but
> it's probably more future proof to provide the symbol.)
> ---
>  src/include/sys/auxv.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/include/sys/auxv.h b/src/include/sys/auxv.h
> index 9358a4a5..63c5bfe9 100644
> --- a/src/include/sys/auxv.h
> +++ b/src/include/sys/auxv.h
> @@ -5,6 +5,6 @@
>  
>  #include <features.h>
>  
> -hidden unsigned long __getauxval(unsigned long);
> +unsigned long __getauxval(unsigned long);
>  
>  #endif
> -- 
> 2.41.0

This is probably okay. Are error/errno semantics expected to be the
same as the public getauxval? IIRC this was a topic of confusion at
one point in the past.

Rich