kbuild: revert "save ARCH & CROSS_COMPILE ..."

Revert commit 575543347b

It caused following issues:

- On architectures where ARCH= setting is used to select between
  32 and 64 bit this was no longer possible without "make mrproper"
- If ARCH was changed then kbuild refused to run "make mrproper"
  because ARCH had changed
- When CROSS_COMPILE was changed people were asked to run "make mrproper"
  but kbuild refused to run "make mrproper" because CROSS_COMPILE changed.
- Spaces in CROSS_COMPILE was not 'supported'
- If an non-existing ARCH= was used kbuild could get stuck

Lessons learned:
. Despite being simple and straghtforward people uses very different
  approaches when building the kernel.

. CROSS_COMPILE is sometimes used for ccache despite cache being
  only a CC frontend so one would have expected CC to be
  used for this purpose.

. And obviously this was not tested widely enough.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Sam Ravnborg 2009-10-11 23:22:58 +02:00
parent c01226c314
commit 2331d1a6cd

View file

@ -179,46 +179,9 @@ SUBARCH := $(shell uname -m | sed -e s/i.86/i386/ -e s/sun4u/sparc64/ \
# Alternatively CROSS_COMPILE can be set in the environment.
# Default value for CROSS_COMPILE is not to prefix executables
# Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
#
# To force ARCH and CROSS_COMPILE settings include kernel.* files
# in the kernel tree - do not patch this file.
export KBUILD_BUILDHOST := $(SUBARCH)
# Kbuild save the ARCH and CROSS_COMPILE setting in kernel.* files.
# Restore these settings and check that user did not specify
# conflicting values.
saved_arch := $(shell cat include/generated/kernel.arch 2> /dev/null)
saved_cross := $(shell cat include/generated/kernel.cross 2> /dev/null)
ifneq ($(CROSS_COMPILE),)
ifneq ($(saved_cross),)
ifneq ($(CROSS_COMPILE),$(saved_cross))
$(error CROSS_COMPILE changed from \
"$(saved_cross)" to \
to "$(CROSS_COMPILE)". \
Use "make mrproper" to fix it up)
endif
endif
else
CROSS_COMPILE := $(saved_cross)
endif
ifneq ($(ARCH),)
ifneq ($(saved_arch),)
ifneq ($(saved_arch),$(ARCH))
$(error ARCH changed from \
"$(saved_arch)" to "$(ARCH)". \
Use "make mrproper" to fix it up)
endif
endif
else
ifneq ($(saved_arch),)
ARCH := $(saved_arch)
else
ARCH := $(SUBARCH)
endif
endif
ARCH ?= $(SUBARCH)
CROSS_COMPILE ?=
# Architecture as present in compile.h
UTS_MACHINE := $(ARCH)
@ -483,11 +446,6 @@ ifeq ($(config-targets),1)
include $(srctree)/arch/$(SRCARCH)/Makefile
export KBUILD_DEFCONFIG KBUILD_KCONFIG
# save ARCH & CROSS_COMPILE settings
$(shell mkdir -p include/generated && \
echo $(ARCH) > include/generated/kernel.arch && \
echo $(CROSS_COMPILE) > include/generated/kernel.cross)
config: scripts_basic outputmakefile FORCE
$(Q)mkdir -p include/linux include/config
$(Q)$(MAKE) $(build)=scripts/kconfig $@