System Control Coprocessor
ARM DDI 0301H Copyright © 2004-2009 ARM Limited. All rights reserved. 3-151
ID012310 Non-Confidential, Unrestricted Access
Table 3-151 lists the encoding for the access permissions for bit fields APX and AP.
Figure 3-79 shows the arrangement of bits in the TLB Lockdown Attributes Register.
Figure 3-79 TLB Lockdown Attributes Register format
Table 3-152 lists how the bit values correspond with the TLB Lockdown Attributes Register
functions.
[3] APX Access permissions extension bit.
Defines the access permissions for this page table entry. See Table 3-151.
[2:1] AP Access permissions, or first sub-page access permissions if the page table entry supports
sub-pages.
[0] V Indicates if this page table entry is valid:
0 = Entry is not valid
1 = Entry is valid.
Table 3-150 TLB Lockdown PA Register bit functions (continued)
Bits Field name Function
Table 3-151 Access permissions APX and AP bit fields encoding
APX AP Supervisor permissions User permissions Access type
0 b00 No access No access All accesses generate a permission fault
0 b01 Read/write No access Supervisor access only
0 b10 Read/write Read only Writes in user mode generate permission faults
0 b11 Read/write Read/write Full access
1 b00 No access No access Domain fault encoded field
1 b01 Read only No access Supervisor read only
1 b10 Read only Read only Supervisor/User read only
1 b11 Read only Read only Supervisor/User read only
C SAP3
31 30 29 28 27 26 25 24 11 10 7 6 5 2 1 0
AP2 AP1
S
P
V
SBZ Domain
X
N
TEX B
3
Table 3-152 TLB Lockdown Attributes Register bit functions
Bits Field name Function
[31:30] AP3 Sub-page access permissions for the fourth sub-page. If the page table entry does not support
sub-pages this field Should Be Zero.
[29:28] AP2 Sub-page access permissions for the third sub-page. If the page table entry does not support
sub-pages this field Should Be Zero.
[27:26] AP1 Sub-page access permissions for the second sub-page. If the page table entry does not support
sub-pages this field Should Be Zero.
To Next Page
Loading...
Need help?
General
