ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

B3.7.4 The effect of the Security Extensions on TEX remapping
Virtual Memory System Architecture (VMSA)
When the Security Extensions are implemented, the MMU remap registers are banked in the Secure and
Non-secure security states. The register versions for the current security state apply to all TLB lookups. The
SCTLR.TRE bit is banked in the Secure and Non-secure copies of the register, and the appropriate version
of this bit determines whether TEX remapping is applied to TLB lookups in the current security state.
When the Security Extensions are implemented, the translation table descriptors include an NS bit. For
security reasons, the NS bit is not accessible through the MMU remap registers.
Write accesses to the Secure copies of the MMU remap registers are disabled when the CP15SDISABLE
input is asserted HIGH, and the MCR operations to access these registers become UNDEFINED. For more
information, see The CP15SDISABLE input on page B3-76.
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