Subject: Re: Per process und_sp
To: Steve Woodford <firstname.lastname@example.org>
From: Chris Gilbert <email@example.com>
Date: 10/30/2005 22:48:01
On Sat, 29 Oct 2005 22:39:43 +0100
Steve Woodford <firstname.lastname@example.org> wrote:
> Is there still a need for a per-process und_sp on our arm32 ports? As
> far as I can tell, it is completely vestigial; all processes can share
> the same und_sp set up by initarm().
I think it might be needed by ARMFPE, but then we don't really use ARMFPE any more. (Is it worth keeping the ARMFPE stuff in tree?)
Is a shared und_sp safe for debugging? (I guess it probably is, as I suspect we used a shared undefined stack for debugging on other platforms)
I presume you're looking for further ways to improve performance? I know that I wondered if we could remove the und_sp stuff from cpuswitch.S, as we've got to change processor modes twice to set and read the und_sp. Which I believe is quite slow.