ACPI: CPPC: Validate SystemIO overlaps across processors

System I/O port space is global, but the overlap check only compares
registers within one _CPC package. Whole-width accesses from different
processors can therefore target partially overlapping port ranges and
clobber each other.

Extend the physical interval registry to SystemIO and remove the
redundant same-descriptor overlap pass, now covered by the registry.
Retain the direction-aware policy from the SystemIO layout check: a
read-only entry may alias a write-only control, but not a readable control
whose readback would then select the wrong register. Also permit read-only
overlaps and exact full-width aliases of the same logical writable CPPC
entry. Reject other overlaps involving a writable entry.

Fixes: a2c8f92bea5f ("ACPI: CPPC: Implement support for SystemIO registers")
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Tested-by: Sumit Gupta <sumitg@nvidia.com>
Link: https://patch.msgid.link/20260916162805.1039247-14-christian.loehle@arm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

0 files changed, 0 insertions, 0 deletions