Re: [PATCH v2 18/21] gcc-plugins: move GCC version check for PowerPC to Kconfig

[Kees Cook]

On Mon, Mar 26, 2018 at 10:29 PM, Masahiro Yamada
<yamada.masahiro@xxxxxxxxxxxxx> wrote:
> For PowerPC, GCC 5.2 is the requirement for GCC plugins.  Move the
> version check to Kconfig so that the GCC plugin menus will be hidden
> if an older compiler is in use.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> Acked-by: Andrew Donnellan <andrew.donnellan@xxxxxxxxxxx>
> ---
>
> Changes in v2: None
>
>  arch/powerpc/Kconfig         | 2 +-
>  scripts/Makefile.gcc-plugins | 8 --------
>  2 files changed, 1 insertion(+), 9 deletions(-)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 73ce5dd..b8474c2 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -195,7 +195,7 @@ config PPC
>         select HAVE_FTRACE_MCOUNT_RECORD
>         select HAVE_FUNCTION_GRAPH_TRACER
>         select HAVE_FUNCTION_TRACER
> -       select HAVE_GCC_PLUGINS
> +       select HAVE_GCC_PLUGINS                 if GCC_VERSION >= 50200
>         select HAVE_GENERIC_GUP
>         select HAVE_HW_BREAKPOINT               if PERF_EVENTS && (PPC_BOOK3S || PPC_8xx)
>         select HAVE_IDE
> diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
> index b0f9108..25da4c0 100644
> --- a/scripts/Makefile.gcc-plugins
> +++ b/scripts/Makefile.gcc-plugins
> @@ -56,14 +56,6 @@ gcc-plugins-check: FORCE
>  ifdef CONFIG_GCC_PLUGINS
>    ifeq ($(PLUGINCC),)
>      ifneq ($(GCC_PLUGINS_CFLAGS),)
> -      # Various gccs between 4.5 and 5.1 have bugs on powerpc due to missing
> -      # header files. gcc <= 4.6 doesn't work at all, gccs from 4.8 to 5.1 have
> -      # issues with 64-bit targets.
> -      ifeq ($(ARCH),powerpc)
> -        ifeq ($(call cc-ifversion, -le, 0501, y), y)
> -         @echo "Cannot use CONFIG_GCC_PLUGINS: plugin support on gcc <= 5.1 is buggy on powerpc, please upgrade to gcc 5.2 or newer" >&2 && exit 1

I think we should retain the "buggy" note as a comment in Kconfig
since that knowledge isn't obvious just from the GCC_VERSION test.

> -        endif
> -      endif
>        $(Q)$(srctree)/scripts/gcc-plugin.sh --show-error $(HOSTCXX) $(CC) || true
>        @echo "Cannot use CONFIG_GCC_PLUGINS: your gcc installation does not support plugins, perhaps the necessary headers are missing?" >&2 && exit 1
>      endif
> --
> 2.7.4
>

-Kees

-- 
Kees Cook
Pixel Security