Messages in this thread | | | Date | Mon, 12 Mar 2001 00:27:14 -0800 | From | george anzinger <> | Subject | Re: [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/
| |