Failure to boot...

[Nicolas Pitre]

On Wed, 30 Jan 2013, Olof Johansson wrote:

> My Panda ES works with omap2plus_defconfig, but I just noticed that the
> in-kernel uImage target will use a bad load/entry address so loading and
> booting that uImage will hang u-boot:
> 
> Image Name:   Linux-3.8.0-rc5-00389-g120d4a8
> Created:      Wed Jan 30 18:30:39 2013
> Image Type:   ARM Linux Kernel Image (uncompressed)
> Data Size:    3843912 Bytes = 3753.82 kB = 3.67 MB
> Load Address: fffffff2
> Entry Point:  fffffff2
> 
> Looking at the latest build and boot log for SDP (oldconfig) on your build
> status site verifies that you hit that case too. :(
> 
> Wrapping by hand (which my scripts already do) produces a bootable image; just
> verified both with and without device-tree on my panda.
> 
> git bisect points at a069486162a59513053cf772515217ca61727704 (ARM: OMAP2+:
> Enable ARCH_MULTIPLATFORM support)
> 
> Hmm. This happens because nothing sources arch/arm/mach-*/Makefile.boot for
> CONFIG_ARCH_MULTIPLATFORM builds, even if only a single platform is enabled,
> since $MACHINE is empty.

The uImage format is incompatible with multi-platform builds, period.

The uImage wrapping should be done at kernel _installation_ time, not at 
_build_ time.  That is, people shoud get into the habit of distributing 
a zImage binary, and the installation procedure on a particular platform 
should take care of running mkimage on it.

Better yet (IMHO): just enable the zboot command in U-Boot to let you 
boot a zImage binary directly.

> It seems like most of the available options to deal with this are bad. One
> thing we should never do though, is to pretend to make a working uImage
> when we're not.  Maybe abort building just like in the case of multiple
> load addresses?

Absolutely.

> diff --git a/arch/arm/boot/Makefile b/arch/arm/boot/Makefile
> index abfce28..71768b8 100644
> --- a/arch/arm/boot/Makefile
> +++ b/arch/arm/boot/Makefile
> @@ -68,8 +68,8 @@ else
>  endif
>  
>  check_for_multiple_loadaddr = \
> -if [ $(words $(UIMAGE_LOADADDR)) -gt 1 ]; then \
> -	echo 'multiple load addresses: $(UIMAGE_LOADADDR)'; \
> +if [ $(words $(UIMAGE_LOADADDR)) -ne 1 ]; then \
> +	echo 'multiple (or no) load addresses: $(UIMAGE_LOADADDR)'; \
>  	echo 'This is incompatible with uImages'; \
>  	echo 'Specify LOADADDR on the commandline to build an uImage'; \
>  	false; \

Acked-by: Nicolas Pitre <nico at linaro.org>


Nicolas