Subject: Re: What's difference between ARM_VECTORS_LOW and ARM_VECTORS_HIGH?
To: None <port-arm@netbsd.org>
From: Toru Nishimura <locore64@alkyltechnology.com>
List: port-arm
Date: 04/13/2007 23:15:12
Steve Woodford says;
> The vector table on older ARM CPUs was hard-wired to 0x0. This requires
> some additional work on the part of the OS to ensure there is always a
> valid kernel mapping at that address in every process, and to deal with
> page faults if userland touches the vector page.
The fact, reset starts at address 0 and exception vector populated next
to it, is the weak point of ARM design. What amused me is PDF says that
the reset value of V bit can be controlled by VINITHI strap, thus not for
the peace mind of SW constract. This can not be a solution for the nature
of reset and runtime exception entry live in the same house. It's the point
I enphasis.
Toru Nishimura/ALKYL Technology