cvs commit: src/sys/i386/i386 vm_machdep.c

[Kris Kennaway]

On Tue, Dec 14, 2004 at 02:55:00PM -0800, Nate Lawson wrote:

> >Erm, well, that's not always easy since sometimes when you panic you can't 
> >talk to the other CPUs for whatever reason.  Putting back the proxy reset 
> >doesn't hurt for now but does restore functionality in at least some 
> >cases.  I'd rather have that then certain hard panics not get into ddb 
> >because we couldn't get onto the BSP to run ddb.
> 
> Perhaps you could give me some pointers on what is counted on to be 
> working when panic() is called?  I can't come up with a situation where 
> the proxy code couldn't be used upon entry to ddb.  If there were any 
> cases like this, the proxy code wouldn't work for cpu_reset() either. 
> Also, in such a case, it's hard to see how ddb could be usable since it 
> tries to stop other processors, which requires similar code to the proxy.
> 
> Or in other words, if you have enough capability to call panic() or 
> break to ddb, then you have enough resources to do an IPI and get onto 
> the BSP.

NB: DDB often isn't usable on SMP machines thesedays, and will hang
when a panic tries to enter it.

Kris
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