Re: [XenPPC] fast_resume instead of full_resume after hdec_out

[HYEONSEUNG JANG <hs8848.jang@xxxxxxxxxxx>]

> But currently 'fast_resume' is called after 'hdec_out'

It should be "But currently 'full_resume' is called after 'hdec_out'"

Sorry for the confusion.




------- Original Message -------
Sender : HYEONSEUNG JANG<hs8848.jang@xxxxxxxxxxx>  E5(??)/Software 
Laboratories/Samsung Electronics
Date   : Sep 11, 2007 13:22
Title  : [XenPPC] fast_resume instead of full_resume after hdec_out

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






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