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
If EL3 is using AArch32, there are separate Secure and Non-secure instances of this register.
If EL3 is using AArch32, write access to NMRR(S) is disabled when the
CP15SDISABLE2
signal is asserted HIGH.
The Non-secure NMRR is architecturally mapped to the AArch64 MAIR_EL1[63:32] register
when TTBCR.EAE==0. See
B2.77 Memory Attribute Indirection Register, EL1
.
The Secure NMRR is mapped to the AArch64 MAIR_EL3[63:32] register when
TTBCR.EAE==0. See
B2.79 Memory Attribute Indirection Register, EL3
.
Attributes
NMRR is a 32-bit register when TTBCR.EAE is 0.
31 30 29 28 27 26 25 24 23
20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
IR0
IR1
IR7
IR6
IR5
IR4
IR3
IR2
22 21
OR0
OR1
OR7 OR6 OR5 OR4 OR3 OR2
Figure B1-53 NMRR bit assignments
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.TR
n
entry.
n
is the value of the TEX[0], C and B bits,
Memory attributes and the n value for the PRRR field descriptions
. The
possible values of this field are:
0b00
Region is Non-cacheable.
0b01
Region is Write-Back, Write-Allocate.
0b10
Region is Write-Through, no Write-Allocate.
0b11
Region 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.TR
n
entry.
n
is the value of the TEX[0], C and B bits,
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 OR
n
field.
B1 AArch32 system registers
B1.99 Normal Memory Remap Register
100236_0100_00_en
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B1-319
Non-Confidential
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