Patent ID: 8881265

Claim:
A computer system including a memory having a secure area, and a first processor and a second processor using the memory, the computer system comprising, as functional components realized by at least one of the first processor and the second processor executing a program stored in the memory: a execution controller managing execution control of a plurality of program units executed by the first processor and the second processor; a start notification receiver receiving an access start notification from one or more access-allowed program units being one or more of the program units for which access to the secure area is allowed, the access start notification indicating that an access to the secure area by the first processor is starting; an end notification receiver receiving an access end notification indicating that the access to the secure area by the first processor is ending; and an execution control value manager managing an execution control value for each of the access-allowed program units, wherein when the access start notification is received by the start notification receiver, the execution controller manages limited execution control such that the second processor is limited to executing one of the access-allowed program units, when the access end notification is received by the end notification receiver during the limited execution control, the execution controller manages execution control such that the limitation is removed, when the access start notification is received by the start notification receiver, the execution control value manager sets the execution control value for each of the access-allowed program units to a predetermined value, and when the access end notification is received by the end notification receiver while the execution control value for each of the access-allowed program units is set to the predetermined value, the execution control value manager sets the execution control value for each of the access-allowed program units to a value other than the predetermined value, and the execution controller manages the limited execution control such that the second processor is limited to executing one of the program units that is one of the access-allowed program units as long as the execution control value for each of the access-allowed program units is set to the predetermined value.