B1.47 Domain Access Control Register

The DACR characteristics are:

Purpose
Defines the access permission for each of the sixteen memory domains.
Usage constraints

This register is accessible as follows:

EL0

(NS)

EL0

(S)

EL1

(NS)

EL1

(S)

EL2

EL3

(SCR.NS = 1)

EL3

(SCR.NS = 0)

- - RW RW RW RW RW
Configurations

There are separate Secure and Non-secure instances of this register at EL3.

DACR has no function when TTBCR.EAE is set to 1, to select the Long-descriptor translation table format.

Attributes
DACR is a 32-bit register.
Figure B1-11 DACR bit assignments
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D<n>, bits [2n+1:2n], for n = 0 to 15, [31:0]

Domain n access permission, where n = 0 to 15. Permitted values are:

0b00No access. Any access to the domain generates a Domain fault.
0b01Client. Accesses are checked against the permission bits in the translation tables.
0b11Manager. Accesses are not checked against the permission bits in the translation tables.

The value 0b10 is reserved.

To access the DACR:

MRC p15, 0, <Rt>, c3, c0, 0 ; Read DACR into Rt
MCR p15, 0, <Rt>, c3, c0, 0 ; Write Rt to DACR

Register access is encoded as follows:

Table B1-41 DACR access encoding

coproc opc1 CRn CRm opc2
1111 000 0011 0000 000
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