Subject: Re: change arm link address?
To: Chris Gilbert <>
From: Ben Harris <>
List: port-arm
Date: 10/23/2003 11:31:31
On Thu, 23 Oct 2003, Chris Gilbert wrote:

> Just browsing over the pmap code, and noticed this comment:
>  *     o If the vector_page is at 0x00000000 instead of 0xffff0000, then
>  *       MP systems will lose big-time because of the MMU domain hack.
>  *       The only way this can be solved (apart from moving the vector
>  *       page to 0xffff0000) is to reserve the first 1MB of user address
>  *       space for kernel use only. This would require re-linking all
>  *       applications so that the text section starts above this 1MB
>  *       boundary.
> I know that currently we don't do MP on arm, there was some work done to
> support hydra MP, and long term I believe that arch v6 chips will
> support SMP (although I'd guess they can remap the vector table)
> However I was wondering if NetBSD 2.0 would be a good day time to do
> this?

This would be bad for arm26, since it would lose a megabyte of our 24 MB
user address space.  If I ever get Hydra support to go properly, I'll
reconsider this, but for now I think it's unnecessary.

If there's any sane (cache-coherent) ARM SMP that doesn't support a high
vector table, that's a different matter, obviously.

Ben Harris                                                   <>
Portmaster, NetBSD/acorn26           <URL:>