Debug Galileo

Mostly it is related to connection problem.

DHCP Server Mis-configuration

Just connect a normal device (your cell phone, laptop) to your DHCP server. If it works, your DHCP server is fine.

Network Problem

If you think maybe it is the network problem, the routing process is wrong, try assign Galileo a static IP to make things simpler. Mount the image's file system on your host by mount -t ext3 -o loop image-full-galileo-clanton.ext3 /tmp/sdcard and edit /etc/network/interfaces to assign eth0 a static IP and gateway. They manually set up path from your host by adding static arp entry arp -s static-ip-of-galileo mac-of-galileo. If all these does not work, your image could be corrupted.

Corrupted Image

1. Are you using partition type master boot record with a FAT32 partition?
2. Did you rename the files corrected? Maybe you delete one more character?
3. Did you copy the images from the same build? For example, every build updates image-full-galileo-clanton.ext3, and core-image-minimal-initramfs-clanton.cpio.gz. Combining two files from different build might not work.

Illegal instruction (SIGILL)

Usually this is due to the wrong flag during cross compilation. SIGILL is sent to a process if it tries to execute an illegal machine-language instructions. Two possible cases are

1. Incorrectly formed machine-language instruction by compiler. In this case, you are probably helpless as you need to fix your compiler.... Usually though, gcc is fairly stable, you get SIGILL because of the second case.
2. Your CPU encounters a unknown instruction (note from CPU's point of view, an ill-formed instruction is the same as an unknown instruction).

The unknown instruction could be generated by your compiler when you issued the wrong flag during cross compilation. But if you cross compiled a bunch of stuff, and the dependencies are a huge mess, how do you quickly know which program or libraries contains the illegal instruction?

The answer is core dump. A core dump is a file containing a memory image of the process at the time it terminated. (The term core derives from an old memory technology.) This memory image can be loaded into a debugger in order to examine the state of a program’s code and data at the moment when the signal arrived.

The following table from tlpi illustrates the default behabior of a process when it receive a signal. core means generating a core dump file. Here we see SIGILL generates a core dump.

However, Galileo's Yocto image is a small system with limited storage, unlike your PC, it does not generate core dump by default (otherwise the filesystem is quickly overloaded with the core file). Enable the core dump by

ulimit -c unlimited

ulimit is a shell utility that set shell and process resource limite. -c flag means to set the limit on the size of a core dump file (default is 0 for the Yocto image, so no core dump is generated). unlimited means... well... unlimited.

In this linux image, core dump is generated to the executing directory of the process that generate core dump. The name of the core dump is core (All this is adjustable, see core pattern). After obtaining a core dump, we can use gdb to analyze it.

Assuming gdb is not available in your Galileo, copy the core file to your SDK tool chain, open it with the executable that generate it gdb ./build/bin/ndnsec -c core -tui you will see something like Here I set sysroot to $PKG_CONFIG_SYSROOT_DIR so that it links to correct libraries.

next give

layout next
r

layout next will show the following machine-language instruction. r will run the program until SIGILL, you can see exactly which instruction in which file gives you the error. And now you can further see if the instruction is in the ISA of Galileo's Intel Quark SoC X1000 Core (see Developer’s Manual).

If it is not, that means when you compile that file, instructions outside i586 architecture is used.