> I've noticed arm/mainbus/mainbus_io_asm.S is broken, and would like to
> commit a fix something like below.
> Are there any problem commiting this?
>
Yes the function used on the RiscPC to access the motherboard IO devices 
including IDE, serial and parallel which make use of all of these routines.
Some of these machines are ARMv3 architecture and have no LDRH support. 

> I greped mainbus_bs in arm32, and arm32 doesn't seem to use these
> functions.
> 
All bus space routines are accessed through pointers to functions so you will 
never find them on a direct grep. I switched mainbus_bs_w_2 for 
bs_notimpl_bs_w_2 and mainbus_bs_r_2 for bs_notimpl_bs_r_2 in mainbus_io.c. I 
then did a recompile and rebooted. At that point the new kernel paniced 
complaining about the missing mainbus functions.

> Half word load and store are ARMv4 only, but I think it's ok.
> They cannot be implemented for v3 and older anyway.
> 
This change will break the RISCPC and GENERIC configs on arm32.

Mike