Re: [RFC PATCH 4/4] LoongArch: Remove -fno-jump-tables for objtool

[Huacai Chen]

Hi, Tiezhu,

On Fri, Jul 12, 2024 at 5:15 PM Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> wrote:
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> ---
>  arch/loongarch/Kconfig  | 8 +++++++-
>  arch/loongarch/Makefile | 6 ++----
>  2 files changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index ddc042895d01..57f28450a2ed 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -143,7 +143,7 @@ config LOONGARCH
>         select HAVE_LIVEPATCH
>         select HAVE_MOD_ARCH_SPECIFIC
>         select HAVE_NMI
> -       select HAVE_OBJTOOL if AS_HAS_EXPLICIT_RELOCS && AS_HAS_THIN_ADD_SUB && !CC_IS_CLANG
> +       select HAVE_OBJTOOL if TOOLCHAIN_SUPPORTS_OBJTOOL && !CC_IS_CLANG
>         select HAVE_PCI
>         select HAVE_PERF_EVENTS
>         select HAVE_PERF_REGS
> @@ -276,6 +276,12 @@ config AS_HAS_LBT_EXTENSION
>  config AS_HAS_LVZ_EXTENSION
>         def_bool $(as-instr,hvcl 0)
>
> +config CC_HAS_ANNOTATE_TABLEJUMP
> +       def_bool $(cc-option,-mannotate-tablejump)
> +
> +config TOOLCHAIN_SUPPORTS_OBJTOOL
> +       def_bool AS_HAS_EXPLICIT_RELOCS && AS_HAS_THIN_ADD_SUB && CC_HAS_ANNOTATE_TABLEJUMP
Can AS_HAS_THIN_ADD_SUB be removed now?

Huacai

> +
>  menu "Kernel type and options"
>
>  source "kernel/Kconfig.hz"
> diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
> index 8674e7e24c4a..186c75c80daa 100644
> --- a/arch/loongarch/Makefile
> +++ b/arch/loongarch/Makefile
> @@ -99,10 +99,8 @@ KBUILD_AFLAGS                        += $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno
>  KBUILD_CFLAGS                  += $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)
>  KBUILD_AFLAGS                  += $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)
>  KBUILD_CFLAGS                  += $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)
> -
> -ifdef CONFIG_OBJTOOL
> -KBUILD_CFLAGS                  += -fno-jump-tables
> -endif
> +KBUILD_AFLAGS                  += $(call cc-option,-mannotate-tablejump) $(call cc-option,-Wa$(comma)-mannotate-tablejump)
> +KBUILD_CFLAGS                  += $(call cc-option,-mannotate-tablejump) $(call cc-option,-Wa$(comma)-mannotate-tablejump)
>
>  KBUILD_RUSTFLAGS               += --target=loongarch64-unknown-none-softfloat
>  KBUILD_RUSTFLAGS_MODULE                += -Crelocation-model=pic
> --
> 2.42.0
>
>