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| author | Sam Ravnborg <sam@ravnborg.org> | 2009-09-20 12:24:55 +0200 |
|---|---|---|
| committer | Sam Ravnborg <sam@ravnborg.org> | 2009-09-20 12:24:55 +0200 |
| commit | 575543347b5baed0ca927cb90ba8807396fe9cc9 (patch) | |
| tree | 2ca85e5c092edef5a779562ebf227b6449e21f6f /Makefile | |
| parent | caa27b66bd7188fd063769eaf4b33533ef0709e6 (diff) | |
| download | lwn-575543347b5baed0ca927cb90ba8807396fe9cc9.tar.gz lwn-575543347b5baed0ca927cb90ba8807396fe9cc9.zip | |
kbuild: save ARCH & CROSS_COMPILE when building a kernel
When building a kernel for a different architecture
kbuild requires the user always to specify ARCH and
CROSS_COMPILE on the command-line.
We use the asm symlink to detect if user forgets to
specify the correct ARCH value - but that symlink
is about to die. And we do now want to loose this check.
This patch save the settings of ARCH and CROSS_COMPILE
in two files named:
include/generated/kernel.arch
include/generated/kernel.cross
The settings are saved during "make *config" time
and always read.
If user try to change the settings we error out.
This works both for plain builds and for O=...
builds.
So now you can do:
$ mkdir sparc64
$ make O=sparc64 ARCH=sparc64 CROSS_COMPILE=sparc64-linux- defconfig
$ cd sparc64
$ make
Notice that you no longer need to tell kbuild
the settings of ARCH and CROSS_COMPILE when you type make
in the output directory.
Likewise for plain builds where you do not use O=...
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Roland McGrath <roland@redhat.com>
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 46 |
1 files changed, 44 insertions, 2 deletions
@@ -179,9 +179,46 @@ 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) -ARCH ?= $(SUBARCH) -CROSS_COMPILE ?= + +# 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 # Architecture as present in compile.h UTS_MACHINE := $(ARCH) @@ -446,6 +483,11 @@ ifeq ($(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 $@ |