IPMI: new NMI handling

Convert over to the new NMI handling for getting IPMI watchdog timeouts via an
NMI.  This add config options to know if there is the ability to receive NMIs
and if it has an NMI post processing call.  Then it modifies the IPMI watchdog
to take advantage of this so that it can know if an NMI comes in.

It also adds testing that the IPMI NMI watchdog works.

Signed-off-by: Corey Minyard <minyard@acm.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 3 deletions

diff --git a/Documentation/IPMI.txt b/Documentation/IPMI.txt
index 83b05459eb5c..bc38283379f0 100644
--- a/Documentation/IPMI.txt
+++ b/Documentation/IPMI.txt
@@ -584,9 +584,11 @@ The watchdog will panic and start a 120 second reset timeout if it
 gets a pre-action.  During a panic or a reboot, the watchdog will
 start a 120 timer if it is running to make sure the reboot occurs.
 
-Note that if you use the NMI preaction for the watchdog, you MUST
-NOT use nmi watchdog mode 1.  If you use the NMI watchdog, you
-must use mode 2.
+Note that if you use the NMI preaction for the watchdog, you MUST NOT
+use the nmi watchdog.  There is no reasonable way to tell if an NMI
+comes from the IPMI controller, so it must assume that if it gets an
+otherwise unhandled NMI, it must be from IPMI and it will panic
+immediately.
 
 Once you open the watchdog timer, you must write a 'V' character to the
 device to close it, or the timer will not stop.  This is a new semantic