core: Add support for quiescing OPAL

Quiescing is ensuring all host controlled CPUs (except the current
one) are out of OPAL and prevented from entering. This can be use in
debug and shutdown paths, particularly with system reset sequences.

This patch adds per-CPU entry and exit tracking for OPAL calls, and
adds logic to "hold" or "reject" at entry time, if OPAL is quiesced.

An OPAL call is added, to expose the functionality to Linux, where it
can be used for shutdown, kexec, and before generating sreset IPIs for
debugging (so the debug code does not recurse into OPAL).

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

0 files changed, 0 insertions, 0 deletions