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From:   Lecopzer Chen <lecopzer.chen@mediatek.com>
To:     <keescook@chromium.org>, <samitolvanen@google.com>,
        <linux-kbuild@vger.kernel.org>
CC:     <clang-built-linux@googlegroups.com>,
        <linux-kernel@vger.kernel.org>, <yj.chiang@mediatek.com>,
        <masahiroy@kernel.org>, <michal.lkml@markovi.net>,
        Lecopzer Chen <lecopzer.chen@mediatek.com>
Subject: [PATCH 2/2] Kbuild: lto: add make version checking
Date:   Wed, 30 Jun 2021 20:14:36 +0800
Message-ID: <20210630121436.19581-3-lecopzer.chen@mediatek.com>
In-Reply-To: <20210630121436.19581-1-lecopzer.chen@mediatek.com>
References: <20210630121436.19581-1-lecopzer.chen@mediatek.com>
MIME-Version: 1.0
Content-Type: text/plain
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LTO with MODVERSION 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 release 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>
---
 arch/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/Kconfig b/arch/Kconfig
index c45b770d3579..1571957bade5 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -632,6 +632,7 @@ 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 MAKE_VERSION_INT >= 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