Normal Memory Remap Register.
The NMRR characteristics are:
- Provides additional mapping controls for memory regions that are mapped as Normal memory by their entry in the PRRR.
- Usage constraints
The accessibility to the NMRR by Exception level is:
EL0 EL1(NS) EL1(S) EL2 EL3(SCR.NS = 1) EL3(SCR.NS = 0) - RW RW RW RW RW
Write access to the Secure copy of NMRR is disabled when the CP15SDISABLE signal is HIGH.
The NMRR is:
- Banked for the Secure and Non-secure states.
- Only relevant if the TTBCR.EAE bit is 0.
- Architecturally mapped on to the MAIR1 register in AArch32 state.
The Non-secure NMRR is architecturally mapped to the AArch64 MAIR_EL1[63:32] register.
The Secure NMRR is mapped to the AArch64 MAIR_EL3[63:32] register.
- See the register summary in Table 4-94 c10 register summary.
See the ARM® Architecture Reference Manual ARMv8 for more information.
To access the NMRR in AArch32 state, read or write the CP15 register with:
MRC p15, 0, <Rt>, c10, c2, 1; Read Normal Memory Remap Register MCR p15, 0, <Rt>, c10, c2, 1; Write Normal Memory Remap Register