- Define user_aarch64_gcs_entry in core-aarch64.proto to store
Guarded Control Stack state (gcspr_el0, features_enabled).
- Extend thread_info_aarch64 with an optional gcs field
Also extend thread_info_aarch64 with an optional gcs field
Signed-off-by: Igor Svilenkov Bozic <svilenkov@gmail.com>