WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-ia64-devel

Re: [Xen-ia64-devel] PATCH: [resent] cleanup + fph handling

To: "Tian, Kevin" <kevin.tian@xxxxxxxxx>, <xen-ia64-devel@xxxxxxxxxxxxxxxxxxx>, "Magenheimer, Dan \(HP Labs Fort Collins\)" <dan.magenheimer@xxxxxx>, "Alex Williamson" <alex.williamson@xxxxxx>
Subject: Re: [Xen-ia64-devel] PATCH: [resent] cleanup + fph handling
From: Tristan Gingold <Tristan.Gingold@xxxxxxxx>
Date: Mon, 24 Apr 2006 11:43:23 +0200
Delivery-date: Mon, 24 Apr 2006 02:39:29 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <571ACEFD467F7749BC50E0A98C17CDD8094E7B7B@pdsmsx403>
List-help: <mailto:xen-ia64-devel-request@lists.xensource.com?subject=help>
List-id: Discussion of the ia64 port of Xen <xen-ia64-devel.lists.xensource.com>
List-post: <mailto:xen-ia64-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ia64-devel>, <mailto:xen-ia64-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ia64-devel>, <mailto:xen-ia64-devel-request@lists.xensource.com?subject=unsubscribe>
References: <571ACEFD467F7749BC50E0A98C17CDD8094E7B7B@pdsmsx403>
Sender: xen-ia64-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: KMail/1.5
Le Lundi 24 Avril 2006 11:06, Tian, Kevin a écrit :
> From: Tristan Gingold
>
> >Sent: 2006年4月24日 16:40
> >Hi,
> >
> >
> >this patch moves switch_to macro from xensystem.h and put its body
> >directly in
> >context_switch.  FP saved and restore is slighly optimized: fph is *still*
> >enabled and not anymore disabled.
> >
> >Misc cleanup.
> >
> >Note: not enabling fph before saving fph in context switch does not work.
> >I
> >will look on this issue.  However,  I think it is worth adding this patch.
>
> If you failed at the first context switch, the possible cause is in head.S
> where psr.dfh is initialized as disabled for idle domain. Then the first
> time when you switch from idle to domain0, disabled fp fault occurs
> unless you explicitly enable psr.dfh like in your patch. This is one place
> where psr value doesn't get from hardware exception.
Good idea, but xensetup() initializes fpu and also calls  ia64_fph_enable() !

Tristan.



_______________________________________________
Xen-ia64-devel mailing list
Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ia64-devel