tree f46c7f42332b598e7cd0a9d50c0f475ebf60ed29
parent 7dbda0377dbc0044f8087eab662ae952039cece9
author Nicholas Piggin <npiggin@gmail.com> 1634036118 +1000
committer Vasant Hegde <hegdevasant@linux.vnet.ibm.com> 1634121480 +0530

HBRT: fix clobbered r16 when host services handlers are called

Skiboot is using r16 as a fixed register containing this CPU pointer,
but we can be called back into from hostboot via the host services
interface, where r16 may have been set by hostboot. Switch this back to
skiboot's CPU pointer before running host services handlers, and then
restore it to the hostboot value before returning.

Fixes: 11ce9612b3aa ("move the __this_cpu register to r16, reserve r13-r15")
Reported-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com>
Tested-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>