[PATCH 1/2] Kbuild: lto: add make-version macros

[Lecopzer Chen]

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

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.
The MAKE_VERSION_INT means MAKE_VERSION in canonical digits integer and
implemnted by imitating CLANG_VERSION.

[1] https://lore.kernel.org/lkml/20210616080252.32046-1-lecopzer.chen@xxxxxxxxxxxx/
Signed-off-by: Lecopzer Chen <lecopzer.chen@xxxxxxxxxxxx>
---
 Makefile                |  2 +-
 init/Kconfig            |  4 ++++
 scripts/Kconfig.include |  3 +++
 scripts/make-version.sh | 13 +++++++++++++
 4 files changed, 21 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 a61c92066c2e..9f2b71fdf23e 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -83,6 +83,10 @@ config TOOLS_SUPPORT_RELR
 config CC_HAS_ASM_INLINE
 	def_bool $(success,echo 'void foo(void) { asm inline (""); }' | $(CC) -x c - -c -o /dev/null)
 
+config MAKE_VERSION_INT
+	int
+	default $(make-version)
+
 config CONSTRUCTORS
 	bool
 
diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
index 0496efd6e117..f956953d0236 100644
--- a/scripts/Kconfig.include
+++ b/scripts/Kconfig.include
@@ -63,3 +63,6 @@ ld-version := $(shell,set -- $(ld-info) && echo $2)
 cc-option-bit = $(if-success,$(CC) -Werror $(1) -E -x c /dev/null -o /dev/null,$(1))
 m32-flag := $(cc-option-bit,-m32)
 m64-flag := $(cc-option-bit,-m64)
+
+# Get the GNU make version with a canonical digit.
+make-version := $(shell,$(srctree)/scripts/make-version.sh $(MAKE_VERSION))
diff --git a/scripts/make-version.sh b/scripts/make-version.sh
new file mode 100755
index 000000000000..ce5af96696cc
--- /dev/null
+++ b/scripts/make-version.sh
@@ -0,0 +1,13 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Print the linker name and its 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