[PATCH 2/3] Kbuild: Implement CONFIG_UIMAGE_KERNEL_NOLOAD

Stephen Warren
2012-03-07T00:30:52Z

This allows the user to use U-Boot's mkimage's -T kernel_noload option
if their arch Kconfig allows it, and they desire.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
---
The next patch enables this new CONFIG_ALLOW_ option for ARM. I assume
that some other architectures will also be able to enable it, but I'm
not familiar enough with any to know which.

init/Kconfig | 15 +++++++++++++++
scripts/Makefile.lib | 15 ++++++++++++---
2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index 6cfd71d..2035562 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -203,6 +203,21 @@ config KERNEL_LZO

endchoice

+config ALLOW_UIMAGE_KERNEL_NOLOAD
+ bool
+
+config UIMAGE_KERNEL_NOLOAD
+ bool "Use mkimage's -T kernel_noload instead of -T kernel"
+ depends on ALLOW_UIMAGE_KERNEL_NOLOAD
+ help
+ uImage files of type "kernel" embed an absolute load and entry point
+ address. If the uImage is loaded to a different address, then the
+ image must be copied the uImage file to the specified load address.
+ This copy is a waste of time if the uImage is in fact completely
+ relocatable. If your kernel and bootloader support it, you can build
+ a "kernel_noload" uImage rather than a "kernel" uImage, which
+ prevents any such copying. If unsure say N.
+
config DEFAULT_HOSTNAME
string "Default hostname"
default "(none)"
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 7b0be18..d9c1c87 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -314,9 +314,18 @@ MKIMAGE := $(srctree)/scripts/mkuboot.sh
UIMAGE_ARCH = $(SRCARCH)
UIMAGE_COMPRESSION = $(if $(2),$(2),none)
UIMAGE_OPTS-y =
-UIMAGE_TYPE = kernel
-UIMAGE_LOADADDR=arch_must_set_this
-UIMAGE_ENTRYADDR=$(UIMAGE_LOADADDR)
+ifeq ($(CONFIG_UIMAGE_KERNEL_NOLOAD),y)
+ UIMAGE_TYPE = kernel_noload
+ # Unused by bootloader:
+ UIMAGE_LOADADDR=0
+ # Entry point relative to actual load address:
+ UIMAGE_ENTRYADDR=0
+else
+ UIMAGE_TYPE = kernel
+ # Absolute addresses:
+ UIMAGE_LOADADDR=arch_must_set_this
+ UIMAGE_ENTRYADDR=$(UIMAGE_LOADADDR)
+endif
UIMAGE_NAME = 'Linux-$(KERNELRELEASE)'
UIMAGE_IN = $<
UIMAGE_OUT = $@
--
1.7.0.4