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-ppc-devel

[XenPPC] fast_resume instead of full_resume after hdec_out

To: "xen-ppc-devel@xxxxxxxxxxxxxxxxxxx" <xen-ppc-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [XenPPC] fast_resume instead of full_resume after hdec_out
From: HYEONSEUNG JANG <hs8848.jang@xxxxxxxxxxx>
Date: Tue, 11 Sep 2007 04:22:52 +0000 (GMT)
Cc: Seung-Mo Cho <seungm.cho@xxxxxxxxxxx>
Delivery-date: Mon, 10 Sep 2007 21:23:08 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-ppc-devel-request@lists.xensource.com?subject=help>
List-id: Xen PPC development <xen-ppc-devel.lists.xensource.com>
List-post: <mailto:xen-ppc-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ppc-devel>, <mailto:xen-ppc-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-ppc-devel>, <mailto:xen-ppc-devel-request@lists.xensource.com?subject=unsubscribe>
Msgkey: 20070911042252535@xxxxxxxxxxx
Reply-to: hs8848.jang@xxxxxxxxxxx
Sender: xen-ppc-devel-bounces@xxxxxxxxxxxxxxxxxxx
In handling hdec exception, non-volatile registers are saved because
context_switch() may be called in the do_softirq(). The fact that we
reach to 'hdec_out' means that there has been no context_switch()
called. But currently 'fast_resume' is called after 'hdec_out'

I think there seems to be no reason to restore non-volatiles at this
point. Becasue MSR_EE is alwyas 0, 'fast_resume' will be enough like the
following. It seems to work well in our HW. Please give me comments or
something.

- Hyeonseung Jang.



diff -r 9071521d4864 xen/arch/powerpc/powerpc64/exceptions.S
--- a/xen/arch/powerpc/powerpc64/exceptions.S   Fri Sep 07 11:39:10 2007 +0100
+++ b/xen/arch/powerpc/powerpc64/exceptions.S   Tue Sep 11 11:38:25 2007 +0900
@@ -514,6 +514,7 @@ hdec_out:
 hdec_out:
     addi r1, r1, STACK_FRAME_OVERHEAD   /* restore stack to cpu_user_regs */
     LOAD_GPRS r14, r15, r1              /* we clobbered r14/r15 in the loop */
+    b fast_resume
 
 /* r1 points to the to-be-restored cpu_user_regs. These could be mid-hypervisor
  * stack (returning into elsewhere in Xen) or at the top of the stack



_______________________________________________
Xen-ppc-devel mailing list
Xen-ppc-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ppc-devel
<Prev in Thread] Current Thread [Next in Thread>