5.5.1. Data access permissions

The access permission bits control access to the corresponding memory region. If an access is made to an area of memory without the required permissions, then a permission fault is raised.

The access permissions are determined by the AP[2:0] bits in the Data Access Permission Registers.

Table 5.7 shows the bit values of the AP[2:0] bits that determines the permissions for Privileged and User data access.

Table 5.7. Access data permission bit encoding

AP[2:0]Privileged permissionsUser permissionsDescription
b000No accessNo access

All accesses generate a permission fault

b001Read/writeNo access

Privileged access only

b010Read/writeRead-only

Writes in User mode generate permission faults

b011Read/writeRead/write

Full access

b100UNPUNP

Reserved

b101Read-onlyNo access

Privileged read-only

b110Read-onlyRead-only

Privileged/User read-only

b111UNPUNP

Reserved

Copyright ©  2005-2007 ARM Limited. All rights reserved.ARM DDI 0338G
Non-Confidential