[PATCH] powerpc: Kconfig: disable CONFIG_COMPAT for clang < 12

[Nathan Chancellor]

On 5/18/2021 1:58 PM, Nick Desaulniers wrote:
> Until clang-12, clang would attempt to assemble 32b powerpc assembler in
> 64b emulation mode when using a 64b target triple with -m32, leading to
> errors during the build of the compat VDSO. Simply disable all of
> CONFIG_COMPAT; users should upgrade to the latest release of clang for
> proper support.
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1160
> Link: https://github.com/llvm/llvm-project/commits/2288319733cd5f525bf7e24dece08bfcf9d0ff9e
> Link: https://groups.google.com/g/clang-built-linux/c/ayNmi3HoNdY/m/XJAGj_G2AgAJ
> Suggested-by: Nathan Chancellor <nathan at kernel.org>
> Signed-off-by: Nick Desaulniers <ndesaulniers at google.com>

Reviewed-by: Nathan Chancellor <nathan at kernel.org>

> ---
>   arch/powerpc/Kconfig | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index ce3f59531b51..2a02784b7ef0 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -289,6 +289,7 @@ config PANIC_TIMEOUT
>   config COMPAT
>   	bool "Enable support for 32bit binaries"
>   	depends on PPC64
> +	depends on !CC_IS_CLANG || CLANG_VERSION >= 120000
>   	default y if !CPU_LITTLE_ENDIAN
>   	select ARCH_WANT_OLD_COMPAT_IPC
>   	select COMPAT_OLD_SIGACTION
>