[PATCH] x86: Fix linking u-boot with ld.lld

[Simon Glass]

On Wed, 20 Oct 2021 at 15:31, Alistair Delva <adelva at google.com> wrote:
>
> When linking the final u-boot binary with LLD, the following link errors
> are seen:
>
> ld.lld: error: can't create dynamic relocation R_386_32 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 arch/x86/cpu/start.o
> >>> referenced by arch/x86/cpu/start.o:(.text.start+0x32)
> [...]
> >>> defined in arch/x86/cpu/start16.o
> >>> referenced by arch/x86/cpu/start16.o:(.start16+0x1C)
>
> According to Nick Desaulniers:
>
> "This is a known difference between GNU and LLVM linkers; the GNU
>  linkers permit relocations in readonly segments (making them not read
>  only), LLVM does not (by default)."
>
> Since U-Boot apparently seems to use relocations in readonly segments,
> change the global linker flags to permit them when linking with LLD by
> specifying '-z notext'.
>
> Signed-off-by: Alistair Delva <adelva at google.com>
> Cc: Nick Desaulniers <ndesaulniers at google.com>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Bin Meng <bmeng.cn at gmail.com>
> ---
>  Makefile | 3 +++
>  1 file changed, 3 insertions(+)

Reviewed-by: Simon Glass <sjg at chromium.org>


>
> diff --git a/Makefile b/Makefile
> index 6f2474baeb..3488b83e14 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -997,6 +997,9 @@ LDFLAGS_u-boot += $(LDFLAGS_FINAL)
>  # Avoid 'Not enough room for program headers' error on binutils 2.28 onwards.
>  LDFLAGS_u-boot += $(call ld-option, --no-dynamic-linker)
>
> +# ld.lld support
> +LDFLAGS_u-boot += -z notext
> +
>  LDFLAGS_u-boot += --build-id=none
>
>  ifeq ($(CONFIG_ARC)$(CONFIG_NIOS2)$(CONFIG_X86)$(CONFIG_XTENSA),)
> --
> 2.30.2
>