[PATCH 2/2] ARM: descend into arch/arm/boot only once to generate boot images

From: Masahiro Yamada
Date: Mon Feb 08 2016 - 00:05:47 EST


Commit 3939f3345050 ("ARM: 8418/1: add boot image dependencies to not
generate invalid images") fixed bad images generation in the parallel
building, but it is not efficient to descend into arch/arm/boot over
and over again. It is also clumsy to display the same log message
"Kernel: arch/arm/boot/Image is ready" a couple of times.

$ make ARCH=arm UIMAGE_LOADADDR=0x80208000 all uImage
[snip]
Kernel: arch/arm/boot/Image is ready
Kernel: arch/arm/boot/Image is ready
Kernel: arch/arm/boot/zImage is ready
Building modules, stage 2.
MODPOST 279 modules
Kernel: arch/arm/boot/Image is ready
Kernel: arch/arm/boot/zImage is ready
UIMAGE arch/arm/boot/uImage
Image Name: Linux-4.5.0-rc3
Created: Mon Feb 8 13:22:53 2016
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 6768768 Bytes = 6610.12 kB = 6.46 MB
Load Address: 80208000
Entry Point: 80208000
Image arch/arm/boot/uImage is ready

This commit allows arch/arm/boot/Makefile to build boot images at once
instead of generating them one by one. Of course, it works correctly
also in parallel building.

Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
---

arch/arm/Makefile | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index d6d453f..6db669e 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -315,13 +315,17 @@ archprepare:
BOOT_TARGETS = zImage Image xipImage bootpImage uImage
INSTALL_TARGETS = zinstall uinstall install

-PHONY += $(BOOT_TARGETS) $(INSTALL_TARGETS)
+PHONY += $(BOOT_TARGETS) $(INSTALL_TARGETS) __build_images

-bootpImage uImage: zImage
-zImage: Image
+$(BOOT_TARGETS): __build_images
+ @:

-$(BOOT_TARGETS): vmlinux
- $(Q)$(MAKE) $(build)=$(boot) MACHINE=$(MACHINE) $(boot)/$@
+__build_images: vmlinux
+ $(Q)$(MAKE) $(build)=$(boot) MACHINE=$(MACHINE) \
+ $(addprefix $(boot)/,
+ $(sort $(filter $(BOOT_TARGETS),$(MAKECMDGOALS)) \
+ $(if $(filter all,$(MAKECMDGOALS)), $(KBUILD_IMAGE)) \
+ $(if $(MAKECMDGOALS),,$(KBUILD_IMAGE))))

$(INSTALL_TARGETS):
$(Q)$(MAKE) $(build)=$(boot) MACHINE=$(MACHINE) $@
--
1.9.1