ANDROID: arm64: Image.gz-dtb build target depends on Image.gz
While doing parallel builds using "make -j" option, I ran into
a build race condition a few times where-in Image.gz-dtb target
starts building before Image.gz is even ready, resulting in a
corrupt Image.gz-dtb kernel image.
How to reproduce -->
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-androidkernel- defconfig menuconfig
+
CONFIG_BUILD_ARM64_APPENDED_DTB_IMAGE=y
CONFIG_BUILD_ARM64_APPENDED_DTB_IMAGE_NAMES="qcom/apq8096-db820c"
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-androidkernel- -j9
<snip> ..
SYSMAP System.map
OBJCOPY arch/arm64/boot/Image
GZIP arch/arm64/boot/Image.gz
DTC arch/arm64/boot/dts/qcom/apq8096-db820c.dtb
Building modules, stage 2.
CAT arch/arm64/boot/Image.gz-dtb
GZIP arch/arm64/boot/Image.gz
.. <snip>
$ du -sh arch/arm64/boot/Image.gz-dtb
28K arch/arm64/boot/Image.gz-dtb
When built with this patch -->
$ du -sh arch/arm64/boot/Image.gz-dtb
8.9M arch/arm64/boot/Image.gz-dtb
Let's make Image.gz-dtb build target depend on Image.gz explicitly.
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 3132997..78df900 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -157,7 +157,10 @@
dtbs_install:
$(Q)$(MAKE) $(dtbinst)=$(boot)/dts
-Image-dtb Image.gz-dtb: vmlinux scripts dtbs
+Image-dtb: vmlinux scripts dtbs
+ $(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
+
+Image.gz-dtb: vmlinux scripts dtbs Image.gz
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
PHONY += vdso_install
