7.13. Domain Access Control

MMU accesses are primarily controlled via domains. There are 16 domains, and each has a 2-bit field to define it.

Two basic kinds of users are supported:


use a domain


control the behavior of the domain

The domains are defined in the Domain Access Control Register. Figure 7.8 illustrates how the 32 bits of the register are allocated to define the 16 2-bit domains.

Figure 7.8. Domain access control register format

Table 7.6 defines how the bits within each domain are interpreted to specify the access permissions

Table 7.6. Interpreting access bits in domain access control register

00No AccessAny access generates a Domain Fault.
01Client Accesses are checked against the access permission bits in the Section or Page descriptor.
10ReservedReserved. Currently behaves like the no access mode.
11ManagerAccesses are not checked against the Access Permission bits so a Permission fault cannot be generated.
Copyright © 1997, 1998 ARM Limited. All rights reserved.DDI 0087E