linux-kernel - Re: [PATCH] kbuild: dummy-tools, fix inverted tests for gcc

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Date:   Sat, 6 Mar 2021 19:40:01 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     Jiri Slaby <jslaby@...e.cz>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kbuild: dummy-tools, fix inverted tests for gcc

On Wed, Mar 3, 2021 at 7:43 PM Jiri Slaby <jslaby@...e.cz> wrote:
>
> There is a test in Kconfig which takes inverted value of a compiler
> check:
> * config CC_HAS_INT128
>         def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0)
>
> This results in CC_HAS_INT128 not being in super-config generated by
> dummy-tools. So take this into account in the gcc script.
>
> Signed-off-by: Jiri Slaby <jslaby@...e.cz>
> Cc: Masahiro Yamada <masahiroy@...nel.org>
> ---


Applied to linux-kbuild/fixes.
Thanks.


We could fix init/Kconfig to use the positive logic as follows,
but I guess (hope) this conditional will go away
when we raise the GCC min version next time.
So, I am fine with fixing this in dummy-tools.




diff --git a/init/Kconfig b/init/Kconfig
index 22946fe5ded9..502594a78282 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -849,7 +849,7 @@ config ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
        bool

 config CC_HAS_INT128
-       def_bool !$(cc-option,$(m64-flag) -D__SIZEOF_INT128__=0) && 64BIT
+       def_bool $(success,echo '__int128 x;' | $(CC) $(CLANG_FLAGS)
-x c - -c -o /dev/null) && 64BIT

 #
 # For architectures that know their GCC __int128 support is sound





-- 
Best Regards
Masahiro Yamada