B1.99 Normal Memory Remap Register

The NMRR characteristics are:

Purpose
Provides additional mapping controls for memory regions that are mapped as Normal memory by their entry in the PRRR.
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

The register is:

  • Used in conjunction with the PRRR.
  • Not accessible when using the Long-descriptor translation table format.
Configurations

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

Attributes
NMRR is a 32-bit register when TTBCR.EAE is 0.
Figure B1-53 NMRR bit assignments
To view this graphic, your browser must support the SVG format. Either install a browser with native support, or install an appropriate plugin such as Adobe SVG Viewer.


ORn, [2n+17:2n+16]

Outer Cacheable property mapping for memory attributes n, where n is 0-7, if the region is mapped as Normal memory by the PRRR.TRn entry. n is the value of the TEX[0], C and B bits, see Memory attributes and the n value for the PRRR field descriptions. The possible values of this field are:

0b00Region is Non-cacheable.
0b01Region is Write-Back, Write-Allocate.
0b10Region is Write-Through, no Write-Allocate.
0b11Region is Write-Back, no Write-Allocate.
IRn, [2n+1:2n]

Inner Cacheable property mapping for memory attributes n, where n is 0-7, if the region is mapped as Normal Memory by the PRRR.TRn entry. n is the value of the TEX[0], C and B bits, see Memory attributes and the n value for the PRRR field descriptions. The possible values of this field are the same as those given for the ORn field.

To access the NMRR:

MRC p15, 0, <Rt>, c10, c2, 1    ; Read NMRR into Rt
MCR p15, 0, <Rt>, c10, c2, 1    ; Write Rt to NMRR

Register access is encoded as follows:

Table B1-84 NMRR access encoding

coproc opc1 CRn CRm opc2
1111 000 1010 0010 001
Non-ConfidentialPDF file icon PDF versionARM 100241_0001_00_en
Copyright © 2016, 2017 ARM Limited or its affiliates. All rights reserved.