lkml.org 
[lkml]   [2001]   [Mar]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] serial console vs NMI watchdog
Keith Owens wrote:
>
> On Sun, 11 Mar 2001 20:43:16 -0800,
> george anzinger <george@mvista.com> wrote:
> >Consider this. Why not use the NMI to sync the cpus. Kdb would have a
> >function that is called each NMI.
>
> kdb uses NMI IPI to get the other cpu's attention. One cpu is in
> control and may or may not be accepting NMI, it depends on the event
> that entered kdb. The other cpus end up in kdb code, spinning waiting
> for a cpu switch. Initially they are not receiving NMI because they
> were invoked via NMI which is masked until they exit. However if the
> user does a cpu switch then single steps the interrupted code, the cpu
> has to return from the NMI handler to the interrupted code at which
> time this cpu starts receiving NMI again.

Are you actually twiddling the hardware, or just changing what happens
on NMI?
>
> The kdb context can change from ignoring NMI to accepting NMI. It is
> easier to bring all the cpus into kdb and let the kdb code decide if it
> ignores any NMI that is being received.

Yes. Exactly.

George
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:22    [W:0.055 / U:0.148 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site