kconfig: show compiler version text in the top comment

The kernel configuration phase is now tightly coupled with the compiler
in use.  It will be nice to show the compiler information in Kconfig.

The compiler information will be displayed like this:

  $ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- config
  scripts/kconfig/conf  --oldaskconfig Kconfig
  *
  * Linux/arm64 4.16.0-rc1 Kernel Configuration
  *
  *
  * Compiler: aarch64-linux-gnu-gcc (Linaro GCC 7.2-2017.11) 7.2.1 20171011
  *
  *
  * General setup
  *
  Compile also drivers which will not load (COMPILE_TEST) [N/y/?]

If you use GUI methods such as menuconfig, it will be displayed in the
top menu.

This is simply implemented by using the 'comment' statement.  So, it
will be saved into the .config file as well.

This commit has a very important meaning.  If the compiler is upgraded,
Kconfig must be re-run since different compilers have different sets
of supported options.

All referenced environments are written to include/config/auto.conf.cmd
so that any environment change triggers syncconfig, and prompt the user
to input new values if needed.

With this commit, something like follows will be added to
include/config/auto.conf.cmd

  ifneq "$(CC_VERSION_TEXT)" "aarch64-linux-gnu-gcc (Linaro GCC 7.2-2017.11) 7.2.1 20171011"
  include/config/auto.conf: FORCE
  endif

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Kees Cook <keescook@chromium.org>

diff --git a/Kconfig b/Kconfig
index 4af1b42ef62eed16632a5bf613973f7af810d0e8..5b55d876af03346a4f1436ffdd2f0221b68ee91c 100644 (file)
--- a/Kconfig
+++ b/Kconfig
@@ -5,4 +5,6 @@
 #
 mainmenu "Linux/$(ARCH) $(KERNELVERSION) Kernel Configuration"
 
+comment "Compiler: $(CC_VERSION_TEXT)"
+
 source "arch/$(SRCARCH)/Kconfig"

diff --git a/Makefile b/Makefile
index 58afa07bdf404b3d861ac53745a89276a38c2773..defb383d8f6caf66590a168f8cd902bda978bfe9 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -442,6 +442,8 @@ export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
 export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
 export KBUILD_ARFLAGS
 
+export CC_VERSION_TEXT := $(shell $(CC) --version | head -n 1)
+
 # When compiling out-of-tree modules, put MODVERDIR in the module
 # tree rather than in the kernel tree. The kernel tree might
 # even be read-only.

diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
index 6a15c4dcc7461b2c426cddb9348f32670fa0df3f..a992f8e94887f9134c0f5ca0362d24afd4ea285c 100644 (file)
--- a/arch/x86/um/Kconfig
+++ b/arch/x86/um/Kconfig
@@ -1,6 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 mainmenu "User Mode Linux/$(SUBARCH) $(KERNELVERSION) Kernel Configuration"
 
+comment "Compiler: $(CC_VERSION_TEXT)"
+
 source "arch/um/Kconfig.common"
 
 menu "UML-specific options"