Re: [PATCH] [v2] kallsyms: ignore ARMv4 thunks along with others

[Ard Biesheuvel]

On Thu, 15 Feb 2024 at 09:32, Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
>
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> lld is now able to build ARMv4 and ARMv4T kernels, which means it can
> generate thunks for those (__ARMv4PILongThunk_*, __ARMv4PILongBXThunk_*)
> that can interfere with kallsyms table generation since they do not get
> ignore like the corresponding ARMv5+ ones are:
>
> Inconsistent kallsyms data
> Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
>
> Replace the hardcoded list of thunk symbols with a more general regex that
> covers this one along with future symbols that follow the same pattern.
>
> Fixes: 5eb6e280432d ("ARM: 9289/1: Allow pre-ARMv5 builds with ld.lld 16.0.0 and newer")
> Fixes: efe6e3068067 ("kallsyms: fix nonconverging kallsyms table with lld")
> Suggested-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Reviewed-by: Ard Biesheuvel <ardb@xxxxxxxxxx>

> ---
> v2: use a regular expression instead of listing each one.
> ---
>  scripts/mksysmap | 13 ++-----------
>  1 file changed, 2 insertions(+), 11 deletions(-)
>
> diff --git a/scripts/mksysmap b/scripts/mksysmap
> index 9ba1c9da0a40..57ff5656d566 100755
> --- a/scripts/mksysmap
> +++ b/scripts/mksysmap
> @@ -48,17 +48,8 @@ ${NM} -n ${1} | sed >${2} -e "
>  / __kvm_nvhe_\\$/d
>  / __kvm_nvhe_\.L/d
>
> -# arm64 lld
> -/ __AArch64ADRPThunk_/d
> -
> -# arm lld
> -/ __ARMV5PILongThunk_/d
> -/ __ARMV7PILongThunk_/d
> -/ __ThumbV7PILongThunk_/d
> -
> -# mips lld
> -/ __LA25Thunk_/d
> -/ __microLA25Thunk_/d
> +# lld arm/aarch64/mips thunks
> +/ __[[:alnum:]]*Thunk_/d
>
>  # CFI type identifiers
>  / __kcfi_typeid_/d
> --
> 2.39.2
>