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Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 82
UG585 (v1.11) September 27, 2016
Chapter 3: Application Processing Unit
Memory Attributes (TEX, C and B bits)
TEX, C, and B bits within the page table entry are used to set the memory attributes of a page and
also the cache policies to be used. Memory attributes are discussed in 3.2.4 Memory Ordering, and
for various cache policies refer to the ARM Technical Reference Manual. Table 3-3 and Table 3-4
summarize these memory attributes.
Table 3-2: Access Permission Encodings
APX AP1 AP0 Privileged Unprivileged Description
00 0No access No access Permission fault
00 1Read/Write No access Privileged access only
01 0Read/Write Read No user-mode write
01 1Read/Write Read/Write Full access
10 0~~ Reserved
10 1Read No access Privileged Read only
11 0Read Read Read only
11 1~ ~~ Reserved
Table 3-3: Memory Attributes Encodings
TEX [2:0] C B Description Memory Type
000Strongly-ordered Strongly ordered
001shareable device Device
010Outer and Inner write through, no allocate on write Normal
011Outer and Inner write back, no allocate on write Normal
100Outer and Inner non-cacheable Normal
1 --Reserved -
10 1 0 Non-Shareable device Device
10 --Reserved -
11 --Reserved -
1XX Y Y Cached memory
XX – Outer Policy
YY – Inner Policy
Normal
Table 3-4: Memory Attributes Encodings
Encoding Bits
Cache Attribute
CB
00Non-cacheable
0 1 Write-back, write-allocate
1 0 Write-through, no write-allocate
1 1 Write-back, no write-allocate