[v2,0/3] watchdog/hpwdt: Cleanup Claiming NMI

Message

Jerry Hoemann Dec. 13, 2023, 9:53 p.m. UTC

In addition to being a watchdog, hpwdt participates in error
containment on ProLiant systems.

On legacy platforms, Gen 9 and earlier, Fatal IO errors would be
signaled as an IO CHECK NMI with expectation that hpwdt would be present
to receive the NMI and crash the systems thus containing the error.

A problem was that hwpdt did not discriminate enough in accepting NMIs.
This could lead to problems if an NMI generated for another subsystem
was not claimed by that subsystem and became UNKNOWN and was claimed
by hpwdt.  Application profiling was such an example.  Although the known
profiling issue was fixed, hpwdt should avoid claiming NMI not intended
for it.

In iLO 5 time frame, checks were added to make hpwdt more selective
in claiming NMI.  This patchset cleans up the checks and enables them
for future versions of iLO.

Updates from V1
---------------
Refactor second patch into two creating a three patch series.
Update and clarify patch documentation.



Jerry Hoemann (3):
  watchdog/hpwdt: Only claim UNKNOWN NMI if from iLO
  watchdog/hpwdt: Remove redundant test.
  watchdog/hpwdt: Remove unused variable

 drivers/watchdog/hpwdt.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)