Re: [PATCH] MIPS: Add comment about CONFIG_MIPS32_O32 in loongson3_defconfig when build with Clang

[Tiezhu Yang]

On 03/04/2021 10:02 AM, Nathan Chancellor wrote:
> On Thu, Mar 04, 2021 at 09:15:44AM +0800, Tiezhu Yang wrote:
> > When build kernel with Clang [1]:
> >
> > $ make CC=clang loongson3_defconfig
> > $ make CC=clang

[snip]

> I think this might be a better solution. I know that I personally never
> read defconfig files if a build fails.
>
> If CONFIG_MIPS32_O32 is broken with clang and the MIPS backend
> maintainer has said that it will not be supported due to lack of
> resources, then the config should not even be selectable in my opinion.
>
> Cheers,
> Nathan
>
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index d89efba3d8a4..ed35318a759d 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -3315,6 +3315,8 @@ config SYSVIPC_COMPAT
>   config MIPS32_O32
>   	bool "Kernel support for o32 binaries"
>   	depends on 64BIT
> +	# https://bugs.llvm.org/show_bug.cgi?id=38063
> +	depends on $(success,$(CC) $(CLANG_FLAGS) -march=mips64 -o32 -c -x c /dev/null -o /dev/null)
>   	select ARCH_WANT_OLD_COMPAT_IPC
>   	select COMPAT
>   	select MIPS32_COMPAT

Hi Nathan,

Thank you very much for your reply and suggestion, maybe the following
change is simple, clear and better? If yes, I will send v2 later.

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 3a38d27..f6ba59f 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -3318,6 +3318,8 @@ config SYSVIPC_COMPAT
 config MIPS32_O32
        bool "Kernel support for o32 binaries"
        depends on 64BIT
+       # https://bugs.llvm.org/show_bug.cgi?id=38063
+       depends on !CC_IS_CLANG
        select ARCH_WANT_OLD_COMPAT_IPC
        select COMPAT
        select MIPS32_COMPAT

Thanks,
Tiezhu