Cortex-A53 Processor AArch32 unpredictable Behaviors
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
B-11
ID021414
Non-Confidential
B.5
Other
UNPREDICTABLE
behaviors
This section describes other
UNPREDICTABLE
behaviors:
•
CSSELR indicates a cache that is not implemented
•
HDCR.HPMN is set to 0, or to a value larger than PMCR.N
B.5.1
CSSELR indicates a cache that is not implemented
If CSSELR indicates a cache that is not implemented, then on a read of the CCSIDR the
behavior is
CONSTRAINED
UNPREDICTABLE
, and can be one of the following:
•
The CCSIDR read is treated as
NOP
.
•
The CCSIDR read is
UNDEFINED
.
•
The CCSIDR read returns an
UNKNOWN
value (preferred).
B.5.2
HDCR.HPMN is set to 0, or to a value larger than PMCR.N
If HDCR.HPMN is set to 0, or to a value larger than PMCR.N, then the behavior in Non-secure
EL0 and EL1 is
CONSTRAINED
UNPREDICTABLE
, and one of the following must happen:
•
The number of counters accessible is an
UNKNOWN
non-zero value less than PMCR.N.
•
There is no access to any counters.
For reads of HDCR.HPMN by EL2 or higher, if this field is set to 0 or to a value larger than
PMCR.N, the processor must return a
CONSTRAINED
UNPREDICTABLE
value that is one of:
•
PMCR.N.
•
The value that was written to HDCR.HPMN.
•
(The value that was written to HDCR.HPMN) modulo 2h, where h is the smallest number
of bits required for a value in the range 0 to PMCR.N.