Subject: Re: change arm link address?
To: Chris Gilbert <firstname.lastname@example.org>
From: Ben Harris <bjh21@NetBSD.org>
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 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 <bjh21@NetBSD.org>
Portmaster, NetBSD/acorn26 <URL:http://www.NetBSD.org/Ports/acorn26/>