On EEH events the kernel will print a dump of relevant registers. If EEH is unavailable (i.e. CONFIG_EEH is disabled, a new platform doesn't have EEH support, etc) this information isn't readily available. Add a new debugfs handler to trigger a PHB register dump, so that this information can be made available on demand. Signed-off-by: Russell Currey <ruscur@russell.cc> Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>