Commit 2331d1a6 authored by Sam Ravnborg's avatar Sam Ravnborg
Browse files

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



Revert commit 57554334

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: default avatarSam 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>
parent c01226c3

Makefile

+2 −44
Original line number Diff line number Diff line
@@ -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 $@

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