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Date:   Sat, 3 Jul 2021 17:16:55 -0700
From:   Nathan Chancellor <nathan@kernel.org>
To:     Lecopzer Chen <lecopzer.chen@mediatek.com>
Cc:     ndesaulniers@google.com, keescook@chromium.org,
        samitolvanen@google.com, linux-kbuild@vger.kernel.org,
        clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org,
        yj.chiang@mediatek.com, masahiroy@kernel.org,
        michal.lkml@markovi.net
Subject: Re: [PATCH v3 2/2] Kbuild: lto: add make version checking
Message-ID: <YOD998U8ekXX7IYh@Ryzen-9-3900X.localdomain>
References: <20210702032943.7865-1-lecopzer.chen@mediatek.com>
 <20210702032943.7865-3-lecopzer.chen@mediatek.com>
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On Fri, Jul 02, 2021 at 11:29:43AM +0800, Lecopzer Chen wrote:
> LTO with MODVERSIONS will fail in generating correct CRC because
> the makefile rule doesn't work for make with version 3.8X.[1]
> 
> Thus we need to check make version during selecting on LTO Kconfig.
> and the suitable version should be 4.2(40200) which released in 2016[2].
> 
> [1] https://lore.kernel.org/lkml/20210616080252.32046-1-lecopzer.chen@mediatek.com/
> [2] https://ftp.gnu.org/gnu/make/
> Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>

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

> ---
>  arch/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 129df498a8e1..beee68149da8 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -639,6 +639,7 @@ config HAS_LTO_CLANG
>  	def_bool y
>  	# Clang >= 11: https://github.com/ClangBuiltLinux/linux/issues/510
>  	depends on CC_IS_CLANG && CLANG_VERSION >= 110000 && LD_IS_LLD && AS_IS_LLVM
> +	depends on !MODVERSIONS || MAKE_VERSION >= 40200
>  	depends on $(success,$(NM) --help | head -n 1 | grep -qi llvm)
>  	depends on $(success,$(AR) --help | head -n 1 | grep -qi llvm)
>  	depends on ARCH_SUPPORTS_LTO_CLANG
> -- 
> 2.18.0