Level 1 Memory System
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
6-18
ID021414
Non-Confidential
Table 6-14
shows the main TLB memory types and shareability.
[65]
NS, descriptor
Security state allocated to memory region.
[64:63]
HAP
Hypervisor access permissions.
[62:60]
AP or HYP
Access permissions from stage-1 translation, or select EL2 or flag.
[59]
nG
Not global.
[58:56]
Size
This field shows the encoding for the page size:
VMSAv8-32 Short-descriptor translation table format:
0b000
4KB.
0b010
64KB.
0b100
1MB.
0b110
16MB.
VMSAv8-32 Long-descriptor translation table format or VMSAv8-64 translation table
format:
0b001
4KB.
0b011
64KB.
0b101
2MB.
0b111
512MB.
[55:40]
ASID
Address Space Identifier.
[39:32]
VMID
Virtual Machine Identifier.
[31]
NS (walk)
Security state that the entry was fetched in.
[30:2]
VA
Virtual Address.
[1]
Address Sign bit
VA[48] sign bit.
[0]
Valid
Valid bit:
0
Entry does not contain valid data.
1
Entry contains valid data.
Table 6-13 Main TLB descriptor data fields (continued)
Bits
Name
Description
Table 6-14 Main TLB memory types and shareability
Bits
Memory type
Description
[7]
Device
0
Non-coherent, Outer WB
Non-coherent, Outer NC
Non-coherent, Outer WT
Coherent, Inner WB and Outer WB
1