Re: [PATCH] ppc: add "-z notext" flag to disable diagnostic

[Nick Desaulniers]

On Thu, Aug 12, 2021 at 1:49 PM Bill Wendling <morbo@xxxxxxxxxx> wrote:
>
> The "-z notext" flag disables reporting an error if DT_TEXTREL is set on
> PPC with CONFIG=kdump:
>
>   ld.lld: error: can't create dynamic relocation R_PPC64_ADDR64 against
>     local symbol in readonly segment; recompile object files with -fPIC
>     or pass '-Wl,-z,notext' to allow text relocations in the output
>   >>> defined in built-in.a(arch/powerpc/kernel/misc.o)
>   >>> referenced by arch/powerpc/kernel/misc.o:(.text+0x20) in archive
>       built-in.a
>
> The BFD linker disables this by default (though it's configurable in
> current versions). LLD enables this by default. So we add the flag to
> keep LLD from emitting the error.
>
> Signed-off-by: Bill Wendling <morbo@xxxxxxxxxx>

Link: https://github.com/ClangBuiltLinux/linux/issues/811
Reported-by: Itaru Kitayama <itaru.kitayama@xxxxxxxx>
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>

>
> ---
> The output of the "get_maintainer.pl" run just in case no one believes me. :-)

LOL!

>
> $ ./scripts/get_maintainer.pl arch/powerpc/Makefile
> Michael Ellerman <mpe@xxxxxxxxxxxxxx> (supporter:LINUX FOR POWERPC (32-BIT AND 64-BIT))
> Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> (reviewer:LINUX FOR POWERPC (32-BIT AND 64-BIT))
> Paul Mackerras <paulus@xxxxxxxxx> (reviewer:LINUX FOR POWERPC (32-BIT AND 64-BIT))
> Nathan Chancellor <nathan@xxxxxxxxxx> (supporter:CLANG/LLVM BUILD SUPPORT)
> Nick Desaulniers <ndesaulniers@xxxxxxxxxx> (supporter:CLANG/LLVM BUILD SUPPORT)
> linuxppc-dev@xxxxxxxxxxxxxxxx (open list:LINUX FOR POWERPC (32-BIT AND 64-BIT))
> linux-kernel@xxxxxxxxxxxxxxx (open list)
> clang-built-linux@xxxxxxxxxxxxxxxx (open list:CLANG/LLVM BUILD SUPPORT)
> ---
>  arch/powerpc/Makefile | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
> index 6505d66f1193..17a9fbf9b789 100644
> --- a/arch/powerpc/Makefile
> +++ b/arch/powerpc/Makefile
> @@ -122,6 +122,7 @@ endif
>
>  LDFLAGS_vmlinux-y := -Bstatic
>  LDFLAGS_vmlinux-$(CONFIG_RELOCATABLE) := -pie
> +LDFLAGS_vmlinux-$(CONFIG_RELOCATABLE) += -z notext
>  LDFLAGS_vmlinux        := $(LDFLAGS_vmlinux-y)
>
>  ifdef CONFIG_PPC64
> --
> 2.33.0.rc1.237.g0d66db33f3-goog
>


-- 
Thanks,
~Nick Desaulniers