kbuild: remove CONFIG_CROSS_COMPILE support

Kbuild provides a couple of ways to specify CROSS_COMPILE:

[1] Command line
[2] Environment
[3] arch/*/Makefile (only some architectures)
[4] CONFIG_CROSS_COMPILE

[4] is problematic for the compiler capability tests in Kconfig.
CONFIG_CROSS_COMPILE allows users to change the compiler prefix from
'make menuconfig', etc.  It means, the compiler options would have
to be all re-calculated everytime CONFIG_CROSS_COMPILE is changed.

To avoid complexity and performance issues, I'd like to evaluate
the shell commands statically, i.e. only parsing Kconfig files.

I guess the majority is [1] or [2].  Currently, there are only
5 defconfig files that specify CONFIG_CROSS_COMPILE.
  arch/arm/configs/lpc18xx_defconfig
  arch/hexagon/configs/comet_defconfig
  arch/nds32/configs/defconfig
  arch/openrisc/configs/or1ksim_defconfig
  arch/openrisc/configs/simple_smp_defconfig

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

diff --git a/Makefile b/Makefile
index 02202d3249624251485e63982a8c59476cbc8f71..58afa07bdf404b3d861ac53745a89276a38c2773 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -316,12 +316,9 @@ SUBARCH := $(shell uname -m | sed -e s/i.86/x86/ -e s/x86_64/x86/ \
 # CROSS_COMPILE can be set on the command line
 # make CROSS_COMPILE=ia64-linux-
 # Alternatively CROSS_COMPILE can be set in the environment.
-# A third alternative is to store a setting in .config so that plain
-# "make" in the configured kernel build directory always uses that.
 # Default value for CROSS_COMPILE is not to prefix executables
 # Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
 ARCH           ?= $(SUBARCH)
-CROSS_COMPILE  ?= $(CONFIG_CROSS_COMPILE:"%"=%)
 
 # Architecture as present in compile.h
 UTS_MACHINE    := $(ARCH)

diff --git a/init/Kconfig b/init/Kconfig
index 18b151f0ddc1fba93777e1ca9f40b9f0fd072711..15aae32e07190e2bbc78348a23c176ffe390ac8e 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -54,15 +54,6 @@ config INIT_ENV_ARG_LIMIT
          Maximum of each of the number of arguments and environment
          variables passed to init from the kernel command line.
 
-
-config CROSS_COMPILE
-       string "Cross-compiler tool prefix"
-       help
-         Same as running 'make CROSS_COMPILE=prefix-' but stored for
-         default make runs in this kernel build directory.  You don't
-         need to set this unless you want the configured kernel build
-         directory to select the cross-compiler automatically.
-
 config COMPILE_TEST
        bool "Compile also drivers which will not load"
        depends on !UML