A8.2
AXI privilege information
AXI provides information about the privilege level of an access on the
ARPROTM[0]
and
AWPROTM[0]
signals. However, when accesses might be cached or merged together, the resulting
transaction can have both privileged and unprivileged data combined. If this happens, the processor
marks the transaction as privileged, even it if was initiated by an unprivileged process.
The following table shows exception levels and corresponding
ARPROTM[0]
and
AWPROTM[0]
values.
Table A8-1 ARPROT and AWPROT values
Processor exception level Type of access
Value of ARPROT[0] and
AWPROT[0]
EL0, EL1, EL2, EL3
Cacheable read access
Privileged access
EL0
Device, or normal Non-cacheable read access
Unprivileged access
EL1, EL2, EL3
Privileged access
EL0, EL1, EL2, EL3
Cacheable write access
Privileged access
EL0
Device, nGnRnE, nGnRE, and nGRE write
Unprivileged access
EL1, EL2, EL3
Privileged access
EL0
Normal Non-cacheable or Device GRE write, except for
STREX
,
STREXB
,
STREXH
,
STREXD
,
STXR
,
STXRB
,
STXRH
,
STXP
,
STLXR
,
STLXRB
,
STLXRH
and
STLXP
to shareable memory
Privileged access
EL0
Normal Non-cacheable write for
STREX
,
STREXB
,
STREXH
,
STREXD
,
STXR
STXRB
,
STXRH
,
STXP
,
STLXR
,
STLXRB
,
STLXRH
and
STLXP
to shareable memory
Unprivileged access
EL1, EL2, EL3
Normal Non-cacheable write
Privileged access
EL0, EL1, EL2, EL3
TLB pagewalk
Privileged access
A8 AXI Master Interface
A8.2 AXI privilege information
100236_0100_00_en
Copyright © 2015–2017, 2019 Arm Limited or its affiliates. All rights
reserved.
A8-107
Non-Confidential
Summary of Contents for Cortex-A35
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