公开(公告)号：US10942865B2

公开(公告)日：2021-03-09

申请号：US16440533

申请日：2019-06-13

Applicant: Arm Limited

Inventor： Gurunath Ramagiri ,  Tushar P. Ringe ,  Mukesh Patel ,  Jamshed Jalal ,  Iat Pui Chan ,  Lakshmi Joga Vishnu Vardhan Badukonda

IPC: G06F12/1081 ,  G06F12/0864 ,  G06F12/0877

Abstract: A method and apparatus are provided to enable snoop forwarding to occur together with memory protection. A data processing apparatus in, for instance, the form of a home node forwards a snoop forwarding request on behalf of a requester to a target, the snoop forwarding request being capable of indicating one or more access permissions of the target in relation to the data. A further data processing apparatus in the form of, for instance, a receiver node may receive the snoop forwarding request and based on its own permissions that are provided in the snoop forwarding request, together with the state of the data, either provide a response back to the requester or the home node. In a still further data processing apparatus in the form of, for instance, a Memory Protection Unit (MPU), a regular snoop forwarding request made to a target in relation to data can be forwarded to the target or demoted to a non-forwarding snoop request based on the permissions of the target in relation to the data at the MPU.