[PATCH v3 1/2] Kbuild: lto: add CONFIG_MAKE_VERSION

From: Lecopzer Chen <lecopzer.chen@mediatek.com>
To: <ndesaulniers@google.com>, <keescook@chromium.org>,
	<samitolvanen@google.com>, <linux-kbuild@vger.kernel.org>,
	<nathan@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 v3 1/2] Kbuild: lto: add CONFIG_MAKE_VERSION
Date: Fri, 2 Jul 2021 11:29:42 +0800	[thread overview]
Message-ID: <20210702032943.7865-2-lecopzer.chen@mediatek.com> (raw)
In-Reply-To: <20210702032943.7865-1-lecopzer.chen@mediatek.com>

To check the GNU make version. Used by the LTO Kconfig.

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.
Add CONFIG_MAKE_VERSION which means MAKE_VERSION in canonical digits
for arithmetic comparisons.

[1] https://lore.kernel.org/lkml/20210616080252.32046-1-lecopzer.chen@mediatek.com/
Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
---
 Makefile                |  2 +-
 init/Kconfig            |  4 ++++
 scripts/make-version.sh | 13 +++++++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100755 scripts/make-version.sh

diff --git a/Makefile b/Makefile
index 88888fff4c62..2402745b2ba9 100644
--- a/Makefile
+++ b/Makefile
@@ -516,7 +516,7 @@ CLANG_FLAGS :=
 
 export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL
-export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
+export PERL PYTHON3 CHECK CHECKFLAGS MAKE MAKE_VERSION UTS_MACHINE HOSTCXX
 export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD
 export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
 
diff --git a/init/Kconfig b/init/Kconfig
index 55f9f7738ebb..ecc110504f87 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -86,6 +86,10 @@ config CC_HAS_ASM_INLINE
 config CC_HAS_NO_PROFILE_FN_ATTR
 	def_bool $(success,echo '__attribute__((no_profile_instrument_function)) int x();' | $(CC) -x c - -c -o /dev/null -Werror)
 
+config MAKE_VERSION
+	int
+	default $(shell,$(srctree)/scripts/make-version.sh $(MAKE_VERSION))
+
 config CONSTRUCTORS
 	bool
 
diff --git a/scripts/make-version.sh b/scripts/make-version.sh
new file mode 100755
index 000000000000..3a451db3c067
--- /dev/null
+++ b/scripts/make-version.sh
@@ -0,0 +1,13 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Print the GNU make version in a 5 or 6-digit form.
+
+set -e
+
+# Convert the version string x.y.z to a canonical 5 or 6-digit form.
+IFS=.
+set -- $1
+
+# If the 2nd or 3rd field is missing, fill it with a zero.
+echo $((10000 * $1 + 100 * ${2:-0} + ${3:-0}))
-- 
2.18.0

