Programmers Model
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
3-9
ID021414
Non-Confidential
Figure 3-1 ARMv8 security model when EL3 is using AArch64
Security model when EL3 is using AArch32
To provide software compatibility with VMSAv7 implementations that include the security
extensions, in Secure AArch32 state, all modes other than User mode have the same execution
privilege. This means that, in an implementation where EL3 is using AArch32, the security
model is as shown in
Figure 3-2 on page 3-10
. This figure also shows the expected use of the
different exception levels and processor modes.
Secure App2
Secure App1
App2
App1
App2
App1
AArch32 or
AArch64
†
Guest OS1
AArch32 or AArch64
‡
AArch32 or
AArch64
†
AArch32 or
AArch64
†
AArch32 or
AArch64
†
AArch32 or
AArch64
†
AArch32 or
AArch64
†
Guest OS2
AArch32 or AArch64
‡
Secure OS
AArch32 or AArch64
Hypervisor
AArch32 or AArch64
Secure monitor
AArch64
EL0
† AArch64 permitted only if EL1 is using AArch64
‡ AArch64 permitted only if EL2 is using AArch64
EL1
EL2
EL3
Non-secure state
Secure state