CPTR_EL3, Architectural Feature Trap Register, EL3
The CPTR_EL3 controls trapping to EL3 of access to CPACR_EL1, CPTR_EL2, trace functionality and registers associated with Advanced SIMD and floating-point execution.
It also controls EL3 access to trace functionality and registers associated with Advanced SIMD and floating-point execution.
Bit field descriptions
CPTR_EL3 is a 32-bit register, and is part of the Security registers functional group.
Figure B2-18 CPTR_EL3 bit assignments
- TTA, 
Trap Trace Access.
Not implemented. RES0.
- TFP, 
Traps all accesses to SVE, Advanced SIMD and floating-point functionality to EL3. This applies to all Exception levels, both Security states, and both Execution states. The possible values are:
Does not cause any instruction to be trapped. This is the reset value.
Any attempt at any Exception level to execute an instruction that uses the registers that are associated with SVE, Advanced SIMD and floating-point is trapped to EL3, subject to the exception prioritization rules.
There are no configuration notes.
Bit fields and details that are not provided in this description are architecturally defined. See the Arm® Architecture Reference Manual Armv8, for Armv8-A architecture profile.