ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Application Level Memory Model
A3.7 Virtual and physical addressing
ARMv7 provides three alternative architectural profiles, ARMv7-A, ARMv7-R and ARMv7-M. Each of the
profiles specifies a different memory system. This manual describes two of these profiles:
ARMv7-A profile
The ARMv7-A memory system incorporates a Memory Management Unit (MMU),
controlled by CP15 registers. The memory system supports virtual addressing, with the
MMU performing virtual to physical address translation, in hardware, as part of program
execution.
ARMv7-R profile
The ARMv7-R memory system incorporates a Memory Protection Unit (MPU), controlled
by CP15 registers. The MPU does not support virtual addressing.
At the application level, the difference between the ARMv7-A and ARMv7-R memory systems is
transparent. Regardless of which profile is implemented, an application accesses the memory map described
in Address space on page A3-2, and the implemented memory system makes the features described in this
chapter available to the application.
For a system-level description of the ARMv7-A and ARMv7-R memory models see:
Chapter B2 Common Memory System Architecture Features
Chapter B3 Virtual Memory System Architecture (VMSA)
Chapter B4 Protected Memory System Architecture (PMSA).
Note
This manual does not describe the ARMv7-M profile. For details of this profile see:
ARMv7-M Architecture Application Level Reference Manual, for an application-level description
ARMv7-M Architecture Reference Manual, for a full description.
A3-40 Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. ARM DDI 0406B