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authorSam Ravnborg <sam@ravnborg.org>2009-09-20 10:24:55 (GMT)
committerSam Ravnborg <sam@ravnborg.org>2009-09-20 10:24:55 (GMT)
commit575543347b5baed0ca927cb90ba8807396fe9cc9 (patch)
tree2ca85e5c092edef5a779562ebf227b6449e21f6f /Makefile
parentcaa27b66bd7188fd063769eaf4b33533ef0709e6 (diff)
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--Makefile46
1 files changed, 44 insertions, 2 deletions
diff --git a/Makefile b/Makefile
index 305d005..a45b0a2 100644
--- a/Makefile
+++ b/Makefile
@@ -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 $@

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