> The doc says place IPL at the reset vector, but the other exception vectors 
> like irq, abort and so on are not mentioned. I have took a look at a portion 
> of codes of a bsp for arm, and did not found information about them too. 
> Anyone can tell me what is done about the other vectors of the arm? Thanks! 

The IPL, or a jump to the IPL, needs to be at the reset vector because the CPU will go there upon power-up. Everything 
else needed to bring up the board will either be done in startup code (e.g. interrupt callouts) or in the drivers for 
each hardware component.

IPL stands for Initial Program Loader. This Program to be loaded will be the startup code. You don't have to worry about
 any other vectors than the reset vector for the IPL. But, of course, as soon as the IPL executes you need to set up 
certain registers to make sure startup can run. Look at an existing IPL to see what it does.

In many cases, a boot loader, e.g. U-Boot, can be used as long as there is no IPL. It will do the very basic init stuff 
for you so you can do startup code.

- Malte