Commit 575543347b5baed0ca927cb90ba8807396fe9cc9
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caa27b66bd
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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>
Showing 1 changed file with 44 additions and 2 deletions Side-by-side Diff
Makefile
| ... | ... | @@ -179,10 +179,47 @@ |
| 179 | 179 | # Alternatively CROSS_COMPILE can be set in the environment. |
| 180 | 180 | # Default value for CROSS_COMPILE is not to prefix executables |
| 181 | 181 | # Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile |
| 182 | +# | |
| 183 | +# To force ARCH and CROSS_COMPILE settings include kernel.* files | |
| 184 | +# in the kernel tree - do not patch this file. | |
| 182 | 185 | export KBUILD_BUILDHOST := $(SUBARCH) |
| 183 | -ARCH ?= $(SUBARCH) | |
| 184 | -CROSS_COMPILE ?= | |
| 185 | 186 | |
| 187 | +# Kbuild save the ARCH and CROSS_COMPILE setting in kernel.* files. | |
| 188 | +# Restore these settings and check that user did not specify | |
| 189 | +# conflicting values. | |
| 190 | + | |
| 191 | +saved_arch := $(shell cat include/generated/kernel.arch 2> /dev/null) | |
| 192 | +saved_cross := $(shell cat include/generated/kernel.cross 2> /dev/null) | |
| 193 | + | |
| 194 | +ifneq ($(CROSS_COMPILE),) | |
| 195 | + ifneq ($(saved_cross),) | |
| 196 | + ifneq ($(CROSS_COMPILE),$(saved_cross)) | |
| 197 | + $(error CROSS_COMPILE changed from \ | |
| 198 | + "$(saved_cross)" to \ | |
| 199 | + to "$(CROSS_COMPILE)". \ | |
| 200 | + Use "make mrproper" to fix it up) | |
| 201 | + endif | |
| 202 | + endif | |
| 203 | +else | |
| 204 | + CROSS_COMPILE := $(saved_cross) | |
| 205 | +endif | |
| 206 | + | |
| 207 | +ifneq ($(ARCH),) | |
| 208 | + ifneq ($(saved_arch),) | |
| 209 | + ifneq ($(saved_arch),$(ARCH)) | |
| 210 | + $(error ARCH changed from \ | |
| 211 | + "$(saved_arch)" to "$(ARCH)". \ | |
| 212 | + Use "make mrproper" to fix it up) | |
| 213 | + endif | |
| 214 | + endif | |
| 215 | +else | |
| 216 | + ifneq ($(saved_arch),) | |
| 217 | + ARCH := $(saved_arch) | |
| 218 | + else | |
| 219 | + ARCH := $(SUBARCH) | |
| 220 | + endif | |
| 221 | +endif | |
| 222 | + | |
| 186 | 223 | # Architecture as present in compile.h |
| 187 | 224 | UTS_MACHINE := $(ARCH) |
| 188 | 225 | SRCARCH := $(ARCH) |
| ... | ... | @@ -445,6 +482,11 @@ |
| 445 | 482 | # used for 'make defconfig' |
| 446 | 483 | include $(srctree)/arch/$(SRCARCH)/Makefile |
| 447 | 484 | export KBUILD_DEFCONFIG KBUILD_KCONFIG |
| 485 | + | |
| 486 | +# save ARCH & CROSS_COMPILE settings | |
| 487 | +$(shell mkdir -p include/generated && \ | |
| 488 | + echo $(ARCH) > include/generated/kernel.arch && \ | |
| 489 | + echo $(CROSS_COMPILE) > include/generated/kernel.cross) | |
| 448 | 490 | |
| 449 | 491 | config: scripts_basic outputmakefile FORCE |
| 450 | 492 | $(Q)mkdir -p include/linux include/config |