[U-Boot-Users] Debugging U-Boot on arm920t using BDI2000

Wed Oct 5 21:06:22 CEST 2005

In message <81E628E8AA1F464C89A772D5018B6D200C4E48 at excbikor.ikor.local> you wrote:
> 
> I'm using BDI2000, and when I try to debug U-Boot the code hangs
> in relocate function in start.S file. The exact instruction that hangs
> the 
> gdb is: "sub r2, r3, r2     /* r2 <- size of u-boot */" 

It's pretty unlikely that it hangs on this specific instruction as it
has register operands only, so there is no reason it could abort

>     1- One problem is that I don't see how the general purpose 
>     registers (r0, r1...) values change, i.e. when "ldr r0, _start"
>     is executed, r0 doesn't change, is this normal? (Is it possible

No, this is not normal.

Are you sure that:

* You have the correct firmware loaded into your BDI2000?
* You use the correct debug cable?
* You use a correct config file?

> When I compile the code,there are no errors or warnings, but a 
> UNDEF_SYM appears:

What do you mean by "appears"? That it's used in the commands?

> UNDEF_SYM=`arm-unknown-linux-gnu-objdump -x lib_generic/libgeneric.a \
> board/LinCon/libLinCon.a cpu/arm920t/libarm920t.a
> cpu/arm920t/imx/libimx.a \
> lib_arm/libarm.a fs/cramfs/libcramfs.a fs/fat/libfat.a fs/fdos/libfdos.a
> \
> fs/jffs2/libjffs2.a fs/reiserfs/libreiserfs.a fs/ext2/libext2fs.a
> net/libnet.a \
> disk/libdisk.a rtc/librtc.a dtt/libdtt.a drivers/libdrivers.a
> drivers/sk98lin/libsk98lin.a \
> post/libpost.a post/cpu/libcpu.a common/libcommon.a |sed  -n -e \
> 's/.*\(__u_boot_cmd_.*\)/-u\1/p'|sort|uniq`;\

The shell variable "UNDEF_SYM" gets defined by the previous statement...

> 	arm-unknown-linux-gnu-ld -Bstatic -T \
> /home/iim/IKOR/LinuxEmpotrado/LinCon/build_tools/u-boot/u-boot-1.1.3/boar
> d/LinCon/u-boot.lds \
> -Ttext 0x08f00000  $UNDEF_SYM cpu/arm920t/start.o \

...and is used here. Thi sis perfectly OK - no reason to worry.

>     2- When I compile u-boot for my Evaluation Board (MX1ADS),
>     this UNDEF_SYM appears, but u-boot works without any problem!
>     Is this a problem, or only a "warning"?

This is no problem, and no warning either. It is perfectly fine.

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Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
A woman should have compassion.
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