System Control
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
4-2
ID021414
Non-Confidential
4.1
About system control
The system registers control and provides status information for the functions implemented in
the processor. The main functions of the system registers are:
•
Overall system control and configuration.
•
Memory Management Unit
(MMU) configuration and management.
•
Cache configuration and management.
•
System performance monitoring.
•
GIC configuration and management.
The system registers are accessible in the AArch64 and AArch32 Execution states. The
execution states are described in the
ARMv8-A architecture concepts
on page 3-4
.
The system registers accessed in the AArch64 Execution state are described in the
AArch64
register descriptions
on page 4-14
.
The system registers accessed in the AArch32 Execution state are described in the
AArch32
register descriptions
on page 4-157
.
Some of the system registers can be accessed through the memory-mapped or external debug
interfaces.
Bits in the system registers that are described in the ARMv7 architecture are redefined in the
ARMv8-A architecture:
•
UNK/SBZP, RAZ/SBZP, and RAZ/WI are redefined as
RES
0.
•
UNK/SBOP and RAO/SBOP are redefined as
RES
1.
RES
0 and
RES
1 are described in the
ARM
®
Architecture Reference Manual ARMv8, for ARMv8-A
architecture profile
.
For more information on the execution states, see the
ARM
®
Architecture Reference Manual
ARMv8, for ARMv8-A architecture profile
.
4.1.1
AArch32 registers affected by CP15SDISABLE
In AArch32 state, the
CP15SDISABLE
input disables write access to certain system registers.
The Cortex-A53 processor does not have any
IMPLEMENTATION
DEFINED
registers that are
affected by
CP15SDISABLE
.
For a list of registers affected by
CP15SDISABLE
, see the
ARM
®
Architecture Reference
Manual ARMv8, for ARMv8-A architecture profile
.